The implementation of the compact gearless elevator system with Permanent Magnet Synchronous Motor is presented. For the purpose of the voltage suppression in the motor input side, the LRC filter is used. The automatic encoder alignment algorithm with rotor pole position is developed, and it is available in the full range of the load. The implemented system makes 11% energy savings comparing the system with the induction motor.

A new control method for precision robust position control of a brushless DC (BLDC) motor using asymptotically stable adaptive load torque observer is presented in the paper. Precision position control is obtained for the BLDC motor system approximately linearized using the field-orientation method Recently, many of these drive systems use BLDC motors to avoid backlashe. However, the disadvantages of the motor are high cost and complex control because of nonlinear characteristics. Also, the load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in [1] using fixed gain. However, the motor flux linkage is not exactly known for a load torque observer. There is the problem of uncertainty to obtain very high precision position control. Therefore a model reference adaptive observer is considered to overcome the problem of unknown parameter and torque disturbance in this paper. The system stability analysis is carried out using Lyapunov stability theorem. As a result, asymptotically stable observe gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current which gives fast response. The experimenta results are presented in the paper.

본 논문에서는 선단부 유니폴라 PWM 방식의 전압원 인버터에 의해 구형파 형태의 전류로 여자되는 브러시리스 직류전동기에서 토크맥동 발생의 주된 원인이 되는 상 전류 전환 및 비이상적인 역기전력 파형에 희한 토크맥동을 저감시킬 수 있는 방식을 제안한다. 또한 실험을 통하여 제안한 토크맥동 저감기법의 효용성을 살펴본다.

This paper describes the controller for the improving speed control the AC servo motor. The microprocessor provides an output to the difference in command. The servo system improves the characteristics of speed control. When the motor is running at the same speed as set by the reference signal, the speed encoder also provides a signal the same frequency. Thus, the microprocessor controlled digital techniques enable to realize the flexible performance and control which was possible with time constant. We can know that PI control using neural networks by 80196 can control efficiently speed of AC Servo motor. Finally experimental results prove excellent performance of this control system. The system can be adaptable to CNC machine.

This paper presents a speed and position sensorless control of permanent magnet synchronous motors using an integral binary observer. In order to improve the steady state performance of the binary observer, the binary observer is formed by adding extra integral dynamics to the switching hyperplane equation. The observer structure and its deign method are described. The experimetntal results of the proposed algorithm are presented to demonstrate the effectiveness of the approach.

A brushless DC motor has the high quality of torque output and silence, has been more widely used in industrial area. As the driver and controller of BLDC motor have been more complicated and precise, simulation method has been much used in motor design. And the output characteristics of BLDC motor is determined by the waveform of BACK-KMF in instinct. But because the conventional model of BLDC motor is obtained by approximation of real nonlinear waveform to ideal trapezoidal waveform, the error is occurred in simulation result. Thus in this paper, for the correction of this error in simulation, the model of real nonlinear waveform considered is proposed, and the simulation result is obtained in case of three-phase, four-poles Y-connected, surface mounted permanent magnet BLDC motor.

The constraint condition is the stator voltage and the stator current to operate the motor in the flux weakening region. The maximum current is limited by the inverter current rating and the machine thermal rating. Given DC link voltage to control the motor in the flux weakening the maximum voltage is determined by considering PWM strategy, dead time, voltage drop of the inverter switching device, and the margin of the voltage for current forcing. In this paper, the new method to determine the available maximum voltage is derived by the analythic method and by considering the factors of the voltage drop. So Determining the maximum voltage is very useful to enlarge the speed operation region in the flux weakening operation, the utility of the maximum voltage is increased.

In this paper, a novel indirect rotor position sensing method is proposed to improve the performance of sensorless drive of brushless DC motors. Fast mode change to the sensorless operation is difficult in the existing indirect rotor position sensing methods because precise rotor position can not be obtained when an excessive input is applied to the drive during synchronous operation mode. To cope with this problem, the relationship between terminal voltage and back-emf waveform is analyzed in this paper, also a novel indirect position sensing method which can detect a precise rotor position at low speed range is proposed. The effectiveness of the proposed method is verified through the experimental results.

DSP를 이용한 Brushless DC (BLDC) 모터의 초고속 센서리스 제어 기법 및 그 결과가 제시된다. 초고속 BLDC 모터의 센서리스 제어를 위해서 주 제어기로 DSP TMS320C240이 사용되며 제어 기법으로는 Pulse Amplitude Modulation(PAM) 기법이 사용된다. RAM 제어 기법을 사용함으로서 인버터는 six-step 방식으로 구동되며 속도 제어는 인버터 DC 링크 앞 단 쵸퍼의 전압 제어에 의해 이루어진다. 회전자 위치는 역기전력 센싱 방식에 의해 추정되며 TMS320C240의 Event Manager Module에 입력되어 Commutation 위치 및 속도가 계산된다. 계산된 속도는 디지털 PI 제어 알고리즘에 의해 처리되며 제어기의 출력은 쵸퍼의 duty 비를 변화시킨다. 개발된 DSP 제어 보드 및 제어 알고리즘의 성능을 시험하기 위해 실험이 수행되었으며 전체 제어 알고리즘은 DSP TMS320C240의 어셈블리 프로그램에 의해 구현된다. 결과로 최고 속도 50000 [rpm]에서 이상적인 응답 특성을 얻을 수 있었다.

The main purpose of the UPS is to supply independent and stable power to connected equipment. In installing and operating the UPS system, songle module, three phase UPS in more benefit than multi module, songle phase UPS in the point of volume and cost. However, when supplying Rectifier with output power form three phase UPS, by connecting auto-transformer, occurred harmonic and ripple current makes output filter damaged and leads to nonlinear current coasted by unbalance load. Therefor, in this paper the aim of concentring compound-wound transformer and harmonic filter is supplying liner current by reducing harmonic and ripple current and improving unbalance in voltage and distortion in current wave.

본 논문은 전력전자 시스템의 방열판 시스템에 대한 이론과 실제 시스템을 고찰하고 있다. 본 논문에는 공냉식과 수냉식 방열 시스템에 관한 내용이 있다.

In this paper, we developed a LCU which can be apply Radiation Monitoring System. LCU composed of Controller and Detector Pulse Input Module and so on. we explained concept of PIG Monitor and a study of Radiation Algorithm. Keywords RMS, LCU, DPIM, CPM

일산복합화력발전소 소내 중요설비에 전력을 공급하는 무정전 전원장치의 출력측 전압파형의 종합 왜율을 IEEE 출력기준인 5%로 억제하여 설비의 안정적 동작을 확보하기 위하여 고조파 분석을 행하였다. 일산복합의 무정전 전원장치는 제어전원공급용으로서 부하가 콘덴서 입력형 정류기의 특성을 갖고 있으므로 3, 5, 7차의 주요 고조파를 포함하고 있다. 따라서 이들 각각에 대하여 부하측에서 본 무정전 전원장치의 임피던스를 작게 하여 전압종합왜율을 5%이하로 낮추어야 한다. 무정전전원장치의 출력전압, 전류 취득 자료를 분석하여 해당 차수의 고조파 제거와 역류개선을 위한 동조필터의 커패시터와 리액터의 용량을 결정하는 방법을 정리하였다.

This paper describes the program of optimally choosing parameter in designing inductor, which applied by fuzzy theory, and verifies the reliability of program to use in design of power supply of electronic machine and information communication. It is available to find optimal value of complex and various parameter, such as core, winding, winding number, and air-gap, etc., needed on designing inductor. We expects to minimize time and cost of inductor design.

전자식안정기 설계에 있어서 중요한 램프의 모델링의 연구이며 이 모델은 기존의 방식에서 요구되는 많은 측정값에 의한 방식과는 달리 2개의 파라메터에 의해 결정되는 장점이 있다. 또한 DSPICE로 구현이 용이하므로 시뮬레이션을 통해서 안정기 회로의 L, C값의 초기값을 선택하는데 유용한 방법이 될 수 있다.

In this paper, the cost-effective design of output reactor which is used to suppress the over-voltage at the motor terminal in the Adjustable Speed Drives(ASD) application is proposed. In the elevator drive system, the power cable length is relatively shorter than other ASD applications and then the over-voltage at the motor terminal depends on the frequency characteristics of the output reactor at the over-voltage operating frequency. The over-voltage suppression mechanism of output reactor in ASD application is analyzed and the dominant parameters of output reactor for the over-voltage suppression are extracted. Using these parameters as the design values and considering the high frequency characteristics of iron core in the reactor, a new cost-effective structure of output reactor is proposed. Experimental results of the conventional reactor and the proposed reactor with a 15kW induction motor are given to verify the proposed scheme.

In this paper, we present the 3DOF force-reflecting interface which allows to acquire force of object within a virtual environment. This system is composed of device, virtual environment model, and force-reflecting rendering algorithm. We design a 3 DOF force-reflecting device using the parallel linkage, torque shared by wire, and the controller of system applied by impedance control algorithm. The force-reflecting behaviour implemented as a function position is equivalent to controlling the mechanical impedance felt by the user. Especially how force should be supplied to user, we know using a God-Object algorithm. As we experiment a system implemented by the interface of 3D virtual object and 3DOF force-reflecting interface, we can feel a contact, non-contact of 3D virtual object surface and sensing of push button model.

A study on simulation using Matlab shows the dynamic condition of a beam on feed-back with encorder. A controller for rapid response interpreted the stability on simulation with pole-placement technique. The effect of response was considered feed-back gain. The result of feed-back is described that various feed-back coefficient shows stable controll systems. It would be expected each result according to controllers.

The windup phenomenon appears and results in performance degradation such as large overshoot, slow settling time when the integral-proportional (IP) controller output is saturated. An anti-windup IP controller is proposed to improve the control performance for the motor drives. The proposed algorithm is applied to the current control of a vector-controlled induction motor driven by a pulse width modulated(PWM) voltage-source inverter. The integral state is separately controlled corresponding to whether the IP controller output is saturated or not. The experimental results show that the current response has much improved performance such as little overshoot and fast settling time.

This paper proposes an interfaces control system to drive a ultrasonic motors(USMs). To touch surfaces and objects created within a virtua environment, the 3 DOF force-reflecting interfaces provides force feedback to users, so to feel touching real things. To effectively display the mechanical impedance of the human hand we need a device with specific characteristics, such as low inertia almost zero friction and very high stiffness. As an actuator for direct drive method, the USMs have many good advantages satisfied these conditions over conventional servo motors. To estimate capability of this interface, we did an experiment. The device works very well, as user are able to detect the edge of the wall and the stiffness of the button.

This paper aims at developing remote contro system to control and monitor distributed various devices through internet or information communication network. SNMP (Simple Network Management Protocol) and rectifier operated in a row are adopted for network management protocol and applied device, respectively. For controlling and monitoring distributed devices in real-time java-environment software is constructed. Also general-use interface controller between network device and applied device is proposed. Finally, seria communication such as RS-232 and RS-485 is used between controller and applied device.

Solar cell generate DC power from sunlight whose power is different at any instance according to condition of variables : insolation and temperature. In order to improve the system utility factor and efficiency of energy conversion, it is desirable to operate the PV system at maximum power point of solar cell under different condition. In this paper, Boost chopper is controlled it output voltage with a new discrete control algorithm for MPPT. PWM signal of DC-DC converter are generated with a 89C51 microcontroller. Switching frequency of DC-DC converter is set at 10KHz. Simulation and experimental results show that the PV system studied in this paper is always operated at maximum power point under different maximum power point of solar cells having stabilized output voltage waveform with relatively small ripple component

AC to DC single phase PWM converter for traction application requires rated high power and voltage. Therefor, series or parallel operation converters are necessary with considering the limitation of the power device specification. This paper compares the characteristic between two parallel operation of conventional PWM converter and Single phase three level converter about comparison of power circuit, cooling system control method and harmonic current by computer simulation.

The goal of this paper is to present instantaneous compensating power flow of active power filters(APFs) by graphical method that could be practicable to compensate the power in both case of behaving in instantaneous rectifying mode and instantaneous inverting mode. To ensure the validity of the proposed method, computer simulation is achieved. Proposed method can be present more exquisite and physically meaningful power flow than conventional method in instantaneous compensating power flow Graph of APFs.

A single-switched series element for series-parallel compensated UPS is proposed. The proposed series element can handle only unidirectional power and the input voltage must be higher than the output voltage. But it is very useful when DC-link voltage is low and isolation transformer is need for output stage since only one active switch is used.

본 연구에서는 고주파 유도가열을 위한 전원장치에 사용되는 인버터 시스템의 대용량, 고조파화를 실현하기 위한 고주파화 기술을 제안하였다. 부한 공진 인버터는 H형 전-브리지(Full-Bridge)로 구성하고 각 암당 IBGT를 2병렬로 조합하여 구성하고 부하는 직병열 공진회로로 구성한다. 스위칭 동작은 8개의 IGBT중 각 ARM당 2개씩 순차 제어하여 고속 대용량의 고주파 전력을 출력시킨다. 또한 스위칭은 스위치 턴온·오프시에 스위칭 손실을 줄이기 위해 ZVS(Zero-Voltage Switching) 기법을 도입한다. 제어는 고정주파수 PWM(Pulse Width Modulation) 제어를 하여 전력변환 효율을 극대화한다.

This paper has described about principle and form of proposed circuit made use of soft switching technology ZVS(Zero-Voltage-Switching) to reduce turn on and off loss at switching. Also, the analysis of the proposed circuit was described by using normalized parameter and operating characteristics has been evaluated as to switching frequency and parameters. Based on the characteristics value, a method of the circuit design is proposed. The theoretical results are in good agreement with the experimental ones. The proposed circuit is considerated to be useful for induction heating and discharge lamp.

In this pager, we studies IGBT VVVF inverter for 1C4M propulsion system of railway traction. This inverter is consisted in inverter stack, DB unit, and control unit. To prove performance of inverter carry out combine test. This test verifies that performance of inverter is excellent.

The AC-to-DC single-phase PWM rectifier for traction applications using high power semiconductor, IGCT is made and tested. Parallel operation of two PWM converter is adopted for increasing capacity of converters. For reducing harmonics, the harmonic content is eliminated by the phase shift between two converters switching phase. The output voltage control is achieved by interns calculation without detecting the input current. The part of PLL used for controlling power factor is simply implemented by software.

This paper presents a new averaged model for controlled on time boost power factor correction (PFC) circuit. The proposed model accurately predicts the average behavior of the PFC circuit, and offers a good alternative in studying the large signal dynamics of the circuit. The accuracy of the model is verified through both computer simulation and experiments.

It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheel-railway adhesion characteristics. The purpose of this paper is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheel-rail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory.

This paper analysis magnetic circuit of toroida SRM and simulate optimal switching angle. In this troidal SRM, two of three phase are energized at an arbitrary instance while it is with only one phase in case of typical SRM. It has many advantages in the size of machine and power efficiency. Not only typically Known topologies witched reluctance motors such as asymmetric converter but full bridge converter are safe to employ

Recently, the application of the linear machine for industrial field is remarkable increased, especially for the gantry machine and machine tool system. In these application, high precise position control performance is essentially required in steady/transient state. This paper presents the generalized PID position control algorithm which have rare sensitivity to mass and disturbance. Through the experimental results, it is shown that the proposed algorithm have good performance for the linear machine drives in the steady state and transient state in spite of the load mass varing.

A method to control the speed of DC motor with one-chip microprocessor PIC using PWM is discussed in this paper. This thesis deals with the DC motor speed control for electric bicycles which may be used as an alternative means of transformation in the future. We tried to design a stable system for controlling the speed of DC motor and materialized an electric bicycle loading this system. Now we are on the way to find out the problems this system has and work out the solutions.

SRM drives generate large vibration and acoustic noise because it is commutated individually by step pulse m.m.f on each phase pole. The frequency or motor speed of peak vibrations and acoustic noises is coincided with the natural resonant frequency of the magnetic structure and frame material. And this radial vibration force is induced on the phase commutation region. This paper suggest the new electromagnetic structure of SRM with auxiliary commutation winding excited d.c e.m.f.. This phase- commutating winding is coupled magnetically between one phase winding and the vibrating force is falled down. As a result, SRM with d.c exciting commutation winding is very useful to reduce vibration and acoustic noise of SRM drive.

This paper presents a driving method of 3-phase 4-poles SRM(switched reluctance motor) drived by switching angle control. In this study, the switching angle is determined from approximated analysis and computer simulation by using MATLAB for high efficiency according to the speed and torque required by load, and then microcontroller controls the switching angle of asymmetrical inverter in SRM driver. Also, we experiment the maximum forque driving and maximum power driving by controlling switching angle available to electric vehicle.

In the high speed range for Vector control of Synchronous Reluctance Motor, the effect of iron loss and the cross-coupling of dq axis currents is dependent on the increase of the operating frequency can not be negligible. In this paper, we propose a decupling Vector control of dq axis current that the effect of iron loss is eliminated, and confirm that through simulation results.

In this paper, a vibration suppression method using an energy stored in winding inductance and an induced voltage of the Linear Stepping Motor(LSM) is shown, and it is applied to a new one-phase excitation method. And a magnetic equivalent circuit is based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. Several dynamic characteristics of the LSM are analyzed by the ACSL with the voltage equations, the force equations and the kinetic equation, and are measured by experimental system.

본 연구에서는 SRM의 토크 리플을 줄이기 위한 설계 방법을 제시한다. SRM의 형상을 최적화하기 위해 유한요소법과 최적화 알고리즘을 적용하였다. 기존의 토크 평균값을 이용한 설계법의 문제점을 제시하고 토크 형태를 구간 별로 목적 함수로 정의하여 토크 형태를 최적화하는 새로운 최적화 문제 정의 방법을 제안한다. 이러한 방법으로 최적화할 경우 SRM의 정적 토크 특성만을 고려한 기존 방법에 비해 고속으로 회전하는 SRM의 토크 성능을 보장할 수 있다는 장점이 있다.

In this paper, we operate Synchronous Reluctance Motor(SynRM) using the two-phase conduction method. Acually SynRM is operated by the sinusoidal PWM method but in home-appliance there is many restrictions of making the motor such as the method of winding, the shape of rotor etc. Therefore it is possible that there is little difference of performance between the two-phase conduction method and the sinusoidal PWM method. In this paper the characteristics of motor noise will be analyzed especially in the case of using the two-phase conduction method by experiment results.

The torque of SRM is developed by phase currents and inductance variation. Phase currents and inductance variation. Phase current is often the controlled variable in electrical motor drives, so it seems natural to use closed loop current controllers. However, the highly nonlinear nature of switched reluctance motors makes optimisation of closed loop current controlled difficult because of saturation effect in magnetic circuit. Therefore, torque generation region is nonlinearly varied according to phase current and rotor position. This paper describes the torque control scheme with neural network that can control varied with load torque. The torque control is simulated by PSIM.

SRM구동을 위한 위치 검출기로 포토 트랜지스터 1개를 이용한 저가형 인코더를 제안하고, 제안된 인코더의 출력신호를 사용하여 간단한 논리회로에 의해 상 스위치 제어방식을 제안하였다. 제안된 상 스위치 제어방식은 스위치 온, 오프 각 지연이 SRM의 운전 속도와 관계없게 되어 안정된 고속운전이 가능하게 되었다.

This paper describes a new method for indirect sensing of the rotor position in switched reluctance motors using fuzzy logic algorithm. Through a novel fuzzy algorithm, the complete SRM magnetizing characterization is first constructed, and then used to estimate the rotor position. And also, the optimized phase is selected by phase selector. To demonstrate the promise of this approach, the proposed rotor position estimation algorithm is simulated for variable speed range.

Switched Reluctance Motor has doubly salient poles in stator and rotor, windings are wound in just stator and no magnet or windings on the rotor. This configuration is robust mechanically and thermally. The inverter of SRM is more robust than that of induction or brushless DC(BLDC) motor, but still its drive is comparatively expensive for home appliance. To drive the conventional three or four-phase SRM, 6 to 8 power switches are required when asymmetric bridge inverter is employed. Generally, more than 50% of the cost for the SRM drive is allocated to power devices and gate drives. This paper proposed single phase SRM that have both radial and axial air gaps. The stator and rotor were stacked with two types of stampings that have different diameters. This configuration is very effective to increase align inductance(Lmax). The high value of Lmax increases the motor efficiency and power density. The proposed single phase SRM(Claw SRM) can be driven by only two power switches. To show the validity of the proposed idea, the analysis using finite element method(FEM) and experimental works are carried out. The proposed SPSRM can be driven with high efficiency and can be made compactly and inexpensively because of high value of align inductance and less number of switches. For the comparison, we used same stator for three-phase and single phase, and slightly different stator and rotor for proposed single phase SRM(Claw SRM)

The switched reluctance drive system is known to provide a good adjustable speed and torque characteristics. However, acoustic noise and higher torque ripple are drawbacks. These drawbacks show the fact that SRM drive is not operated with mmf current specified for dwell angle and input voltage. Reducing torque ripple and having precise speed control, PLL technique is adopted. The PLL system in conjunction with dynamic dwell angle control scheme has good speed regulation characteristics. A TMS320F240 based on the DSP is used to realizing this drive system. Test results show that the system has the ability to achieve good dynamic and precise speed control.

The current boost type atatic excitation system for synchronous generator that can sustain prope output voltage level even at fault condition is proposed. The proposed excitation system is capabl of supplying level 60% of the rated voltage. The proposed system is verified and tested using computer simulations as well as load tests. The load tests are performed with a 5KVA synchronous generator driven by a ac motor. The actual tests results indicated a good performance.

In this paper, an algorithm of reconstructing the armature current of the battery car is presented by using MOSFET's on-voltage of the dc chopper and a corresponding circuit is developed with the low-cost analog multiplexer. For driving comfort, the armature current of the motor or the traction force should be properly controlled when the car changes the direction and is accelerated or decelerated and climbs up or down the hill. Therefore, an information of the current is needed for the traction control. The proposed reconstruction algorithm is experimentally verified.

이 논문은 3300V 정격의 PT와 NPT HVIGBT의 스위칭 특성을 비교하여 제시한다. 실제적인 응용을 고려하여 hard 스위칭 조건에서 실험하여 얻어진 데이터 수치들을 보인다. 이 비교 평가가보다 나은 스위칭 특성들을 얻기 위한 기반이 될 수 있을 것이다.

There exists an acute need for high voltage solid-state-switches in a broad area of applications. With the proposed method using simple voltage balancing circuit with series connected IGBTs, it is realized high voltage semiconductor switches with working voltages of several order kilo-volts. The operation principle of the proposed circuit is explained and analyzed. Transient and static voltage-balancing is tested on a experimenta 3kV/45A switch with four series-connected IGBTs.

A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the necessary voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. The circular-current, however, could be occurred when the system is driven in parallel. As a result, the new batteries are heated by over-change and discharge, and the over charge current makes to increase the rust of the positive grid and consequently the shortened life of the new batteris would be shown. In this paper, the internal resistance of charge and discharge will be balanced, through inserting the resistance into the system by way of calculation of the changed amount of internal resistance.

IGBT 소자는 고전류 밀도의 특성을 지니면서 구동전력이 작기 때문에 500V 이상의 고전압 응용에서 널리 이용되고 있다. 본 논문에서는 기존의 IGBT 소자의 구동회로가 갖는 기본기능 이외에 소자에 대한 보호기능과 소자의 동작 상태를 감지하기 위한 모니터링 기능을 갖는 지능형 구동회로에 대해 제안한다. 제안된 회로는 소자에 비정상적인 큰 전류가 흐를 경우 논리회로에 의해 게이트 구동전압을 일정시간 즉시 차단하여 소자를 과전류와 과열로부터 보호하고, 소자의 동작 상태가 정상인지 차단 상태인지 감지할 수 있다. 언급한 기능을 가진 구동회로가 제시되며, 제안된 회로의 동작은 Pspice를 이용한 시뮬레이션 및 실험을 통해 확인된다.

We introduce the systematization design method using similarity theory which is profitable in the compatability, the reduction of construction time and price. The design method can make us predict the characteristic experiment for the magnitude we desire as the expression equation applied continuously. We can induce the design sample the user demand with the verification of the data on optimum design previously. Therefore, in case of designing and developing the products, systematization design method is very useful for the standardization of the developed goods, compatability, the reduction of construction time and price. In this paper, we presented the analogical algorithms of systematization design using similarity theory, design factors and processing method of the restriction factors. Also, we analyzed the output voltage in terms of input voltage and displacement as choosing a differential transformer as the model.

Started upon it discovery by Wright et al in 1973, studies on the solid polymer electrolyte are being carried out vigorously. So, models of Li-polymer battery have been developed through R-L-C components combination and P-spice functional block in this paper. The impedance characteristics of Li-polymer battery with R-L-C components are presented. Simulation results using P-spice functional model are compared with measured charge/discharge characteristics.

The recent problems such as the rapid increase o electricity consumption, the large variation of electrical loads, and the sitting difficulty for new power plants could become a barrier to stable electrical power supply. Consequently, an electrical load management technology has become important, by which an electricity can be stored during off-peak time and efficiently used during peak time. The technology provides a variety of direct or indirect benefits which include, for utilities, reduction of new power plants, economical electricity production, and improved efficiency and reliability of power system and for consumers, low prices o electricity. The study is to develop a proto-type load management system and its application technology for a peak shaving. In the system, conventional batteries are used as energy storage device.

The design and implementation of thyristor water cooling control systems in considered in this pape Coolant water is pumped through the thyristor heat sinks where heat is transferred from the thyristo to the water. This water is then pumped through outdoor air-to-water heat exchangers where heat I transferred to the outside air. Since the water must be pure, it is filtered and de-ionized. Also the water temperature must be below dew-point temperature. Redundant pumps, outdoor heat exchangers, power supply system, controller monitoring system are provided for system reliability and availability.

In order to radiate X-ray, the low ripple stabilized high voltage DC over the range of 40KV to 150KV is directly inflicted to X-ray tube. The energy characteristics of the radiated X-ray depend on the pulsating waveforms of the DC voltage supplied X-ray tube. In general, the low ripple voltage waveforms with fast rising times are required to increase with the dosage per unit time lest the exposure time should be longer in orde that the motion artifacts of an object may be eliminated in actual. The conventional types of X-ray generators were bulky in physical size and heavy in weight, and the control accuracies of the output voltages were not always satisfactory. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing new power semiconductor devices. To decreasing the volume and the weight of high voltage transformer, and to stabilize ripple, a high frequency PWM inverter is connected between DC source and high voltage transformer. This paper describes the output characteristics according to stabilize ripple of X-ray tube voltage and compared the reproducibility, direcibility and doesage.

오존은 다른 산화제에 비해 산화력이 훨씬 높아 수처리에 많이 쓰인다. 본 논문에서는 오존 발생량, 오존 농도와 관계가 있는 주요 파라미터들의 손쉬운 제어를 위해 그래픽 사용자 인터페이스 모니터링 시스템을 구현하였다. 이 시스템은 Windows 98 환경의 PC에서 Turbo C와 LabVIEW를 사용하여 프로그램밍하며, 이 모니터링 시스템은 인버터를 제어하는 80196 Microprocessor와 양방향으로 통신한다. 본 연구에서는 모니터링 시스템이 가져야 할 오존 발생기 개발 단계에서 각 파라미터들의 최적값 결정과 오존 발생기 제조 단계에서 파라미터들의 조정이라는 두가지 목적에 적합하도록 그래픽 환경 사용자 인터페이스 구축에 그 초점을 맞추어 관리자가 효율적으로 오존 발생을 모니터링할 수 있게 한다.

An electrolytic capacitor is widely used in a motor drive system. Therefore, the deterioration diagnosis of an electrolytic capacitor is needed of preventive maintenance of the system. In this paper, we propose a new diagnosis method for the electrolytic capacitor by using the system identification method, which presents the information about the capacitor's interna parameters in on-line operation an use fuzzy algorithm for the deterioration decision. We demonstrated the effectiveness of the proposed control scheme by using computer simulation.

Recently, according to developing industry and life style, power consumption have been increased year after year. Currently these much power demand from power consumer is weakening the allowable power reverse margin in summer. As on of the remedies about this problem, the small scale grid-connected photovoltaic system is considered for auxiliary power source. Generally, grid-connected inverter have a isolation transformer for electrical isolation from utility. This paper propose transformerless system topology an inquiry the validity using simulation.

A new dead-time compensation method using a disturbance observer is proposed. The dead-time causes the voltage distortion and it can be considered as the disturbance voltage. In this paper, the disturbance voltage is estimated by minimal order observer in the d-q frame and the estimated disturbance voltage is summed with voltage command by a feed-forward. The experiments are carried out for the DSP-based BLDC motor drive system and the results show the effectiveness of the proposed method.

A new PWM method for voltage source inverters is described. The switching instants determination of the proposed PWM scheme is simple. Therefore, hardware implementation with a microprocessor system is easy and high frequency operation of an inverter can be obtained. The maximum line-to-line output voltage of 3-phase inverter with the proposed scheme is larger than that of the SPWM inverter under a linear modulation region. Principle of the proposed PWM method is described and harmonic characteristic analysis is carried out.

This paper describes a novel control method of a three-phase PWM inverter for uninterruptible power supply(UPS) applications. To obtain the fast dynamics and excellent harmonic characteristics, a new state feedback control technique is proposed. The proposed control consists of the inner-loop current and outer-loop voltage controllers with a load current estimator to reduce the effects of the load variations and nonlinearity. In order to verify the effectiveness of the proposed control, the simulation is carried out for various load condition.

Several power factor correction(PFC) circuits are presented to achieve high PF electronic ballast for both voltage-fed and current-fed electronic ballast. The proposed PFC circuits use valley-fill(VF) type DC-link stages modified from the conventional VF circuit to adopt the charge pumping method for PFC operations during the valley intervals. In voltage-fed ballast, charge pump capacitors are connected with the resonant capacitors. In current-fed type, the charge pump capacitors are connected with the additional secondary-side of the power transformer. The measured PF and THD are higher than 0.99 and 15% for all proposed PFC circuits. The lamp current CF is also acceptable in the proposed circuits. The proposed circuit is suitable for implementing cost-effective electronic ballast.

This paper describes the characteristics of two methods about providing information needed for propulsion device control in train. The one is to use new way using the communication network for transmission of control information, the other is traditional way using hardwire connection. And this paper describes the communication interface technique between TCMS(Train Control and Monitoring System) and VVVF inverter system with LonWorks network adapted to SMG line 6 which has been developed. With this technique, an inertia load test carried out for the traction control environment and it is expecting a field test at SMG line 6.

The paper describes a implementation of space vector pulse-width modulation (SVPWM) voltage source inverter using Field Programmable Gate Array(FPGA) for a induction motor control system. The implemented chip is included logic circuits for SVPWM, dead time compensation and speed detection using Quick Logic, QL16X24B. The maximum operating frequency and delay time can be set to 110MHz and 6 nsec. The designed FPGA for SVPWM can be incorporated with a digital signal processing to provide a simple and effective solution for high performance voltage source inverter drives. Simulation and Implementation results are shown to verify the usefulness of FPGA as a Application Specific Integrated Circuit(ASIC) in power electronics applications

In a utility interactive photovoltaic system, a PWM inverter is used for the connection between the photovoltaic arrays and the utility. The DC current becomes pulsated causes the distortion of the AC current waveform. This paper presents the reduced pulsation of DC input current by operating the inverter with buck-boost chopper in the discontinuous conduction mode. The DC current with contains harmonics component is analyzed by means of separating into two terms of a ripple component and a direct component. The constant DC current without pulsation is supplied from photovoltaic array to the inverter. The proposed inverter system provide a sinusoidal AC current for domestic loads and the utility line with unity power factor.

This paper presents a vector control of parallel drive, a beatless control and a low switching PWM technique for the propulsion system of Electric car as transient state which are included interrupting line voltage, changing line voltage slowly, suddenly, regenerating light load and starting from backward running. Improved performance and a validation of proposed method is shown by the experimental results using a 1.65MVA IGBT VVVF inverter and inertia load equivalent to 160 tons electric cars through a running and transient state test.

This paper describes an optimal design method of VSI output filter for CVCF system. The cost function is used for design, and all parameters are described in p.u(per unit) so that can be adapted to the change of CVCF rating. The capacitor current feedback scheme is proposed to control the damping ratio of the filter plant to meet the system more stable. This means that the LC resonance can be suppressed well in transient condition and can use the same control gains under the change of system capacity. The validity of the proposed method is well verified with the theoretical analysis and simulation results.

Line starting using contactors is a conventional method for escalator system Recently, comsumer's requirements for energy saving and variable functions are increasing To satisfy this demands, LG Industrial Systems Co., Ltd. has developed an escalator which is driven by inverter system. In this paper, technical schemes of the developed escalator are introduced and the performance of the proposed system is proved by experiment.

In this paper, the diode bridge-type ZVT(Zero-Voltage Transition) inverter is proposed. It consists of one auxiliary switch, three resonant inductors and six blocking diodes. So, the advantage of the proposed topology is the reduction of the auxiliary switch. The topology of the proposed ZVT inverter is analyzed with a description of the control conditions based on the load current. Therefore, this paper two control algorithms were discussed. A variable resonant pattern control algorithm by using load current feedback and a resonant period control algorithm by using resonant inductor current feedback is proposed in order to achieve the ZVT switching condition in full control range and the reducing current spike main switches cause by reverse recovery problem.

An analog implementation of space vector PWM is proposed in this paper. It is shown that a space vector PWM can be implemented by adding a zero sequency voltage to reference voltage of triangle comparison PWM. The proposed scheme is implemented by six diodes and, an operational amplifier circuit and, a few resistors.

Traction system of 2-motor driven electric vehicle(EV) is consisted of motor(IPMSM), inverter, and battery. In order to enhance dynamic characteristics of the system, such driving conditions as acceleration ability and load(current magnitude) should be considered in the vector control algorithm for the IPMSM. So, in this paper, the most suitable structure of vector control algorithm for the EV is considered. Conformity had been verified through experimental results.

This paper proposes a novel current control method of three-phase PWM rectifiers without phase current sensors. The features of this method are to reconstruct phase currents by using switching pattern of space vector modulation and to estimate phase currents by a predictive state observer for practical applications. Simulation results show that the performance of the proposed system is nearly the same as that of sensor-based system.

This paper presents the design method of a repetitive controller to educe the harmonics in the output voltage waveform of the AC power supply systems. Output voltage error under the nonlinear load like a rectifier is cyclic with the same period to fundamental wave, therefore one can design the repetitive controller calculating cycle by cycle. The controller is verified mathematically and by simulations.

In the 3-phase PWM converter, accurate detection of the supplied voltage phase is very important. But a detecting circuit cannot avoid generating the deviation of phase detector so that we need to compensate it. In this paper, an accurate and simple compensating method of deviation of phase detector is proposed.

This paper presents a novel single-stage Power Factor Corrected(PFC) AC/DC forward converter with semi-automatic current shaping in order to achieve the unity power factor and an isolated output. Since the proposed circuit is combined a boost converter used for PFCs with a forward converter used for DC to DC conversion, the over-all size of system could be reduced. And thanks to the zero voltage switching(ZVS) in both switches, the voltage stress can be reduced considerably. A simple auxiliary circuit adopted into the secondary of transformer is composed of lossless components for reducing surge voltage. A prototype which has tow IGBT(Insulated Gate Bypolar Transistor) modules as switching device is manufactured to evaluate the proposed topology. The characteristics of the proposed circuit are tested, and the validity is verified by experimental results.

For decrease the harmonic current components of the power source, a first method is insert the choke coil that used the choke input type rectifier, the booster chopper circuit and buck chopper circuit. And the several method are studying like as the PWM(Pulse Width Modulation) converter and the active filter type which is used the high frequency switching and the sinusoidal wave formed input current. In this type, there are many problem as a low efficiency, increased the noise, the high leakage current and cost up by the high frequency switching. For improve this problems, the partial resonan method is used on the booster inducter and lossles snubber condenser. This method decreased the distortion factor has lower harmonic components than the hard switching and there is no switching loss by the ZCS(Zero Current Switching) at switch turn-on and the ZVS(Zero Voltage Swithcing) at switch turn-off

In this paper, six harmonic injection PWM method for reducing total harmonic distortion in single switch three phase discontinuous conduction mode boost converter is presented. In the proposed method, periodic six harmonic voltage is injected in the control circuit to vary the duty ratio of the converter switch within a line cycle so that the fifth order harmonic of the input current is reduced. Experimental results are verified by converter operating at 400V/6kW with three phase 140V~220V input.

This paper presents the DQ transfomation space space vector modulation method to devel control algorithm of distribu STATCON(STATic CONdenser) for line volt regulation, dc link voltage regulation harmonics compensation. The Performance an of a PI with ramp comparision and synchro reference frame current controller is carried Based on these analysis, the control perform are desirable to compensate the harmonics a regulate dc link and line voltage of Distrib line.

PWM controlled line-side converters of modern ac traction locomotives inject harmonic currents into the feeding overhead line. This causes problem of electromagnetic interference. Passive and Active filters are usually provided for a reduction of the line harmonics. Active filters are more reasonable than passive filters in terms of weight and space of the filters. Successful control of active filters requires an accurate harmonic current reference. A technique to generate the harmonic current reference is proposed in this paper. The analysis is performed in frequency domain and its effectiveness is verified by simulation.

This paper describes a current regulated PWM boost type rectifier based on modified trapezoidal PWM. Each switch of a converter has no switching for one third period of a fundamental line current. Therefore, the switching loss of the proposed scheme is less than that of the hysteresis current controller. Operating principle is described and controller. Operating principle is described and simulations and experiments are carried out.

This paper proposes a new series-connected diode rectifier which draws sinusoidal input currents. The proposed rectifier system is configured by adding an auxiliary circuit to the conventional 12-pulse series-connected diode rectifier and employing a current injection technique. A low kVA (0.02Po (PU) ) active current source injects a triangular current results in near sinusoidal input current from the utility with less than 1% THD. The resulting system is suitable for high voltage and high power applications. Experimental results is provided from a 220VA rectifier system.

In this paper, a new simple control method for active power filter which can realized the complete compensation of the harmonic currents is proposed. In the proposed scheme, a compensating current reference generator employing lossless resonato implemented by a DSP(Digital Signal Processor) is introduced. Deadbeat control is employed to contro the active power filter. The switching pulse width based SVM(Space Vector Modulation) is adopted so that the current of active power filter is been exactly equal to its reference at the next sampling instant. To compensate the computation delay of digital controller, the prediction of current is achieved by the current observer with deadbeat response.

This paper is proposed Single phase Multi-Level AC-DC Converter. This is consist of diode bridge and switches. The number of the supply current levels depends on the number of the individual converter's current level. In this converter circuit the number of the levels is equal to 2(M+1) -1, where M is the number of Switching-Leg's number. In this paper is introduced converter with 31 current Level. If the number of current level is increased, smoother sinusoidal waveform can be obtained. The feasibility of the circuit is verified by computer simulation using PSIM

In auxiliary block of high speed train power factor correction and harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. But the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increased switching frequency. This paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

In this paper, the method of reducing harmonics and correcting of power factor in single PWM converter associated with diode rectifier and boos converter is studied. The ac-dc converter in which the harmonic distortion in the input current is reduced using a third harmonic injected PWM is proposed. A lower switching power loss and easy configuration o control circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[KHz] switching frequency are presented and correction of power factor and reduction of total harmonic distortion was established.

In this paper, an inverter fed induction motor drive system is analyed in order to predict the conducted interference. High frequency model for inverter, motor and system parasitic components are proposed. High frequency component allows time and frequency domain analysis to be performed with standard PSpice tool. The overall high frequency component and model are verified by comparing simulation and experimental result.

This paper propose a "common mode voltage damper" that is capable of reducing the common mode voltage produced in the PWM VSI. An push-pull circuits and high frequency leakage current damper[1] are incorporated into the "common mode voltage damper", the design method of which is presented. Effect of "common mode voltage damper" is simulated in this paper verifies the viability and effectiveness in 2.2kW induction motor drive using IGBT inverter. Simulated results show that "common mode voltage damper" makes significant contributions to reducing a high frequency leakage current.ducing a high frequency leakage current.

This paper presents a implementation of digital motion control system for induction motor vector drives using the 16bit DSP TMS320F240. The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent controllers for induction motors which can be yield enhanced operation, fewer system components, lower system cost, increased efficiency and high performance. The system presented are speed and current sensing, sine look-up table and generated SVPWM by fully integrated control software. The developed system in a implementation are shown a good speed response characteristic results and high performance features. The system can be adapted variform motor drive system.

In this paper, by means of Lyapunov second method, the stability of IPD control servo systems is analyzed in the time domain for the first time. Based on the results of the stability analysis, the design rule to select the gain of IPD control is suggested such that the maximum error of output to the nominal system is guaranteed for all uncertainty and load variations. An example of a position control of a brushless dc motor is given to prove the unusefulness of the gain design rule.

In this paper a Direct Torque Control(DTC) scheme for PWM three level inverter-fed induction motor drives, is presented and discussed. In orde to deal with DTC scheme applied three level inverter, the selection of voltage vector is proposed to minimize switching frequency and torque ripple. The simulation results shows a validity of the control scheme.

For high performance ac drives, the speed sensorless vector control and a speed control algorithm base on the Fuzzy PI controller have received increasing attention. A Fuzzy PI controller is used for robust and fast speed control and space vector modulation method is used for PWM wave generation in this proposed system. The computer simulation results show that the proposed controller are more excellent control characteristics than conventional PI controller in transient-state response.

Direct Torque Control method for an Induction Motor is presented which is quite different from field-oriented control. It carries out a precise and quick control of the stator flux and electromagnetic torque of an IM without calling for coordinate transformation, speed measurement, and stator current control. In principle, moreover, DTC operation requires only the knowledge of the stator resistance.

The single sensor technique reconstructing phase currents from the dc-link current without phase current sensors in proposed. When the duration of active vector is too short for the snubber current to reduce, the dc-link current including the snubber current gives large detection error. The solution is presented by analyzing the snubber current and modifying the switching sequences. This scheme is simple, requires only one sampling a period and has good results for detecting the phase currents.

For a man's approaching limitation in radiation environment, all work must be performed with remoted system to ensure worker's safety and reliability from radiation damage. The remoted system is mostly used in visual observation CCTV system. In high radiation environment of unclear power plant, RI(Radio-isotope) facility, medical radiation treatment facility must be used to radiation tolerant CCTV cameras for radiation damage. We have studied a radiation basic performance of camera components and CCTV cameras to develop radiation tolerant CCTV cameras. As a result, we are able to design a radiation tolerant camera of 108 rad total dose.

Potential-source controlled excitation system had been developed for synchronous generator in In-Chun thermal power plant #4 by KEPRI. This paper describes the characteristics of Main/Standby control system employed analog, digital circuit devices (hybrid type) and 3 PCRs(Phase Controlled Rectifier)

This paper presents design and analysis of an HID lamp ballast for a fast turn on characteristics and stable operation. It produces a high open circuit voltage for the ignition and it is controlled to supply effectively the power required to shorten the warm-up period after the breakdown. The lamp modeling by empirical data is presented. It is very effective in the designing of the control loop in the steady-state operating region. A stable operation of the lamp power regulation in the steady state is achieved, which is crucial for the long life time and constant light output. Stability analysis of the system is performed and the results are verified through various simulation results and the hardware experiments.

It is expected that industrial accelerator having been distributed fast in domestic these days will be widely used for various fields. In this study we deal with the basic consideration for the drive characteristic of power supply system in the system of industrial accelerator installed at Dongshin University. Beam energy of this system is 34keV~40KeV, 100A. The modulator emits a 11KV-380A pulse of $4.5\mu\textrm{s}$ duration that is transformed to about 34KV-40KV pulse by a pulse transformer.

This paper deals with stand-alone Photovoltaic system(SPVS) with charger/discharge controller. Main power source of SPVS are generally solar cel and battery. Therefore SPVS can be classified into variable types in accordance with connection type between battery and solar cell. SPVS with charger/discharge controller which can operate solar cell a maximum power point is suggested and designed with instantaneous controller. And system operating characteristics are verified by experiment with a laboratory prototype in this paper.

This paper describes a driving scheme of the series hybrid electric vehicle that we have developed. Both series HEV and parallel HEV are well known. We chose series HEV because it provides good energy efficiency in urban driving and operates in all-electric mode in performance. And engine-Generator is driven at constant speed with constant load to maintain the low emission. And the battery supplies power during high-load and receive energy during low-load

This paper presents a S-FES(Superconducting magnetic bearing Flywheel Energy Storage System) for the purpose of replacing battery used to store the energy. Especially, the design elements of FES, such as the bearing, wheel material, and power converter, etc., is described. The design and manufacturing techniques of the controllable power converter are proposed to generate the sinusoidal output current in the high speed operation and to get the constant DC voltage in the regeneration mode. The cylindrical permanent magnet synchronous motor with halbach array of Nd-Fe-B permanent magnet which is the high coercivity material is used as the driver of FES. The proposed S-FES system shows the stable rotation characteristics at high speed range about 10,000 rpm. To verify the validity of proposed system, the comparative study with the conventional ball bearing system is proceeded and it is well confirmed with the result of the lower friction loss of S-FES system.

This paper presents design of controllers for battery energy storage system. The proposed battery energy storage system can be controlled to operate in the power conditioning mode or the inverter mode. The operation of this mode further divided into three cases: (a) in the peak load period, the load power supplied from the utility is minimized as far as possible; (b) in the off-peak load period, the utility supplies power to the load and charges the battery bank with automatic charging control; (c) in the medium load period, to save battery energy the real power flow out of the battery energy storage system is minimized. Besides, in all cases, the proposed battery energy storage system also automatically compensates the harmonics, subharmonics and reactive power factor in the utility side are much improved. Simulation results are presented by the effectiveness of the proposed controllers for battery energy storge system.

Nowadays, the inverter for CCFL(Cold-Cathode Fluorescent Lamp) driver is needed as form of compact size, low loss and high efficiency. This paper deals with comparison of characteristics of the electromagnetic push-pull type inverter and the piezoelectric half-bridge inverter for a CCFL driver. From the experimental results, the piezoelectric inverter is proven as more efficient than conventional electromagnetic inverter.

In this paper presents a modeling method for simulation of Tration Motor using Matlab/Simulink This model is well adopted in the traction motor and speed, torque estimation. This model consist o IM(induction motor) block, Load block and controller blocks. This paper use the indirect vecto control Because improve accuracy speed characters. The result show the better speed and torque characters. And effectiveness of Matlab/Simulink in simulations.

The AC drive systems of a voltage source inverter and an induction motor. The inverter non linearity caused by the turn on/off time dependency of the current level in the switching IGBT is described in the first part of this paper. To improve the low-speed drive characteristics, accurate applied voltage calculation is proposed under considerations of the compensations for the quantization error in the digital controller, the forward voltage drop of switching drives and the dead time of the inverter. The experimental studies show the improved drive characteristics.

This paper describes controller development for a dynamic voltage compensator using a shunt diode converter and series inverter. The control system was designed using 1/4 period integrator and vector relationship between the supply voltage and load voltage. A simulation model and scaled hardware model were developed for analyzing performance of the controller and the whole system. Both results confirm that the dynamic compensator can restore the load voltage under the fault of the distribution system.

일반적인 전동기부하는 저속에서 큰 토크를 필요로 하지 않으므로, 인버터로 전동기를 구동하고자 할 때는 낮은 평균전압이 필요하다. 그러나 전력전자 소자의 제한된 스위칭 주파수, 단락 방지를 위한 데드타임 그리고 스위치나 다이오드 도통전압 등으로 인하여, 전류제어 루프 내에는 비선형성이 존재한다. 이러한 비선형성은 디지털 방식의 PWM에서 저전압을 합성할 때 현저하게 나타나는데 결과적으로 교류전동기의 저속운전을 어렵게 한다. 본 논문에서는 기존 디지털방식 PWM의 비선형성을 모델링 하고 그 비선형성을 감소시킬 수 있는 공간벡터 변조기법을 제시하였다.

This paper presents about EL(electroluminescent) driver with inverter. Inverter is composited two FET to increase safety output voltage. As result this study, the optimum operating condition of inverter is that the gate bias frequency of FET equal two resonant frequency of circuit. It shows to ideal sinusoidal output wave. Finally, EL sampler(15cm$\times$15cm) gain 2.6 [lux] with 1cm.

A new multi-step voltage source inverter is proposed in this paper. The proposed scheme is composed of the double-connected 12-step inverter with an auxiliary circuit. The auxiliary circuit includes two voltage dividing capacitors, two switching devices and a low KVA autotransformer. The resultant system is shown to be a 24-step inverter suitable for large scale SVC applications in which the PWM method can not be employed. The design parameters are derived from the analysis of voltages and currents by means of switching functions. The simulation results verify the proposed concept.

This paper deals with the harmonic reduction technique in square-wave inverters which can regenerate the dc power from dc bus line to ac bus line in substations for traction systems. To reduce the harmonics, two 6-pulse inverters are used for 12-pulse operation and zigzag-connected output transformers for eliminating the harmonics of 6(2m-1)$\pm$1 orders. And an ac filter is furnished at output side. In spite of the square-wave three-phase inverters, computer simulations show that the THDs of the output voltage and current are 2.55% and 0.554%, respectively.

In this paper, the method of Space-Vector Pulse Width Modulation(SVPWM) with Fuzzy Logic Regulator(FLR) is proposed. In a conventional SVPWM, the procedures of phase transformation and choosing PWM patterns are complex. So, it should be implemented with high performance processor like Digital Signal Processor(DSP). In order to reduce a calculation burden, a proposed system adopts FLR. Using a linguistic contro strategy based on expert knowledge, FLR relieves the processor from a heavy computations. In simulations, the proposed system is validated.

An improved series-parallel resonant converter using auxiliary winding of resonant is presented. The conventional series-parallel resonan converter and newly developed converter are compared for high voltage application. This proposed converter gives several merits such a wide load ranges, small circulating current, low peak voltage at no load. Two experimental results for the proposed converter and conventional one are presented for conventional LCC type converter and the proposed one.

일반적으로 3상 PWM AC/DC 컨버터는 정상상태 에러 제거 및 빠른 과도응답 특성을 얻기 위해 동기 좌표계상으로 모델링하여 제어한다. 그러나 이와 같은 제어기는 입력전압이 평형일 경우를 전제조건으로 하므로, 입력전원이 불평형인 경우 입력전류와 출력전압에 고조파 성분이 나타나게 된다. 본 논문에서는 전원전압을 동기좌표계상의 정/역상 분으로 분석한 후 두 축(D, Q)의 역기전력 보상성분을 전원전압의 상태에 따라 적절하게 가변하고, 무효 전력과 고조파 전력 성분을 선택적으로 제거함으로써 입출력 시스템의 역률 및 고조파 성분을 효과적으로 보상하기 위한 간단하면서도 효과적인 제어기법을 제안하고, 시뮬레이션과 실험을 통하여 검증하였다.

In this paper, a design technique of SMPS using plannar transformer is described. The application of plannar transformer can solve the space problem which occurs when it is installed on PCB since plannar transformer has low profile. In addition a lossless snubber circuit added to reduce the device stress and to improve the system efficiency. The designed system is verifed by simulation and experiment with comparison of efficiency between the system using conventional transformer and the system using plannar transformer.

In this paper, a current control system for single phase PWM AC/DC converter without the source voltage sensors is proposed. The sinusoidal input current and unity effective power factor are realised based on the estimated source voltage in the controller. The estimation of source voltage is performed by the reduced-order Luenberger observer using actual currents. The estimated source voltage is used to accomplish unity power factor. The proposed method is proved by experiments.

This paper proposes a control method for three-phase voltage-source PWM converters using only a single current sensor in the DC link. A predictive current controller for the voltage-source PWM converter is used so that all phase currents can be reconstructed in a switching period although one or two of active vectors are applied only for a short time. Compensation of the 2 step delays is also included. In this paper single sensor current control using predictive state observer will be discussed, and investigated experimentally.

A new soft switching single stage AC-DC full bridge boost converter with unit input power factor and isolated output is presented in this paper. Due to the use of a non-dissipative snubber on the primary side, a single stage high-power factor isolated full bridge boost converter has a significant reduction of switching losses in the main switching devices. The non-dissipative snubber adopted in this study consists of a snubber capacitor Cr, a snubber inductor Lr, a fast recovery snubber diode Dr, and a commutation diode Dr, and a commutation diode Dp. This paper presents the complete operating principles, theoretical analysis and experimental results.

고속전철의 보조 전원 장치는 차량에 탑재되므로 소형화, 경량화 및 고신뢰성이 요구된다. 보조전원 장치중 Battery Charge는 고압의 직류전원(670Vdc)을 저압의 직류전원(83Vdc)으로 변환하여 객차(Trailer Car : 50kW) 및 동력차(Power Car : 10Kw)에 필요한 직류전원을 안정되게 공급하고 Battery Charger의 고장 발생 시를 대비해 Battery의 최적 충전상태를 유지해야 한다. 기술개발의 최종 목표는 고효율, 고신뢰성 밧데리 충전기 시스템 개발, EMI 저감, 부피와 무게의 소형경량화, 최적 스위칭 기술 및 회로 개발이다. IGBT에 대해 소프트 스위칭 기법을 사용하여 스위칭 손실 저감 및 소자의 스트레스의 저감으로 전력 변환 장치의 효율 향상과 소자의 신뢰성을 확보하였고, 스위칭 주파수를 높여 변압기나 인덕터등의 자기 소자의 크기를 줄였다. Battery Charger를 단일 모듈로 구성하기 보다 5kW 모듈을 여러개 조합한 다중모듈방법으로 병렬 운전하므로써 입출력 전류리플룰 감소시켰으며 시스템의 안정성과 신뢰성을 높일 수 있었다.

과거 벡터 제어의 모델링에 있어 무시되어온 철손의 영향이 최근 여러 논문들에서 연구되어졌으며, 이의 영향이 적지 않음이 밝혀졌다. 본 논문은 속도 센서리스에서의 철손으로 인한 영향을 보상, 직접 회전자 자속 제어와 직접 고정자 자속 제어에 적용하였다. 또한 센서리스 제어에서의 철손의 영향과 그 보상 방법을 보여주며, 시뮬레이션을 통해 이러한 제안의 타당성을 보인다.

Conventional adaptive speed estimators cannot avoid the influence of the non-linear inductance variation under the saturation conditions. Without speed sensors, it is difficult to identify the inductance variation using a reactive power mode because the model contains a term of the rotor speed. In this paper, we propose a novel speed estimator having hybrid architecture in order to estimate both the rotor speed and the inductance variation simultaneously when the motor flux is saturated. Proposed estimator consists of the error between the flux obtained from the stator voltage equation and the flux estimated from the rotor flux observer. Introducing a new correction term into the estimator increases the estimation ability of the conventional speed estimator even though the motor flux is saturated. The convergence of the speed estimation error is examined by simulation Furthermore, the experimental results show the validity of the proposed method.

본 논문은 유도전동기의 직접벡터제어 시스템에서 전동기가 기동 시 토크 충격없이 부드럽게 기동할 수 있는 기동기법을 제시한다. 직접 벡터제어에서 고정자 자속을 계산 시 사용되는 적분기 문제를 해결하기 위하여, 인버터주파수에 따라 시정수를 제어하는 프로그램어블 3-단계 저역필터를 적용한다. 이 3-단계 저역필터는 거의 완벽한 적분기능을 수행 할 수 있으나, 이 저역필터는 고정자 자속의 시간지연을 유발하므로 기동 시 전동기 토크의 충격을 발생된다는 문제점이 있다. 따라서, 기동시 고동자 자속의 시간지연을 보상하는 고장자 자속의 피이드포워드 기법을 제시하여, 전동기 기동 시 토크 충격을 방지한다. 시뮬레이션을 통하여, 이 기동기법의 타당성을 확인한다.

산업 현장에서 널리 사용되고 있는 권선형 유도전동기의 완전한 벡터제어를 속도 검출기를 사용하지 않고 슬립 주파수를 추정하여 구현할 수 있는 알고리즘을 제안했다. 기존의 센서리스 벡터제어 알고리즘의 전동기의 저항의 변동에 대하여 아주 민감하지만 본 논문에서 제안된 알고리즘은 여자 전류 및 슬립주파수 측정에 전동기 2차 저항을 필요로 하지 않아 전동기 정수 변동으로 인한 벡터제어의 불완전함을 제거했다. 시뮬레이션을 통하여 제안된 알고리즘의 우수한 특성과 그 타당성을 확인을 하였다.

This paper describes high speed squirrel cage induction motor drives without speed sensors using neural network based on Kalman filter Learning. High speed motors are receiving inverasing attentions in various applications, because of advantages of high speed, small size and light weight with same power level. Larning rate by Kalman filtering is time varying, convergence time fast, effect of initial weight between neurons is small.

This paper describes a simple but effective method for energy saving of ac motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, in voltage control with triac. In this paper, authors present the experimental results of the SPIM under controlling of current of main and auxiliary winding by using a one chip microcontroller. Experiments are focused on a capacitor stating single phase induction motor the optimal energy saving are proved by the proposed method.

This paper presents a newly developed speed sensorless drive using Neural Network algorithm. Neural Network algorithm can be divided into three categories. In the first one, a Back Propagation-based NN algorithm is well-known to gradient descent method. In the second scheme, a Extended Kalman Filter-based NN algorithm has just the time varying learning rate. In the last scheme, a Recursive Least Square-based NN algorithm is faster and more stable than the classical back-propagation algorithm for training multilayer perceptrons. The number of iterations required to converge and the mean-squared error between the desired and actual outputs is compared with respect to each method. The theoretical analysis and experimental results are discussed.

벡터제어기법은 유도전동기의 무부하 시험 및 구속시험 등을 통하여 구한 고정자 및 회전자 상수를 이용한 전동기의 수학적 모델을 기초로 하여 이루어진다. 따라서 유도전동기의 수학적 모델을 구성하는 고정자 및 회전자 상수의 정확성은 곧 벡터제어의 성능과도 직결된다. 하지만, 온도 상승 등의 영향으로 회전자 저항값은 정상치보다 최대 80∼100%까지 상승 할 수 있으며, 이는 벡터제어의 특성을 저하시키는 요인이 된다. 따라서, 본 연구에서는 회전자 저항을 이용하는 자속 PI제어부를 회전자 저항을 사용하지 않는 자속 퍼지제어부로 대체하고 측정한 3상 전류를 이용하여 회전자 저항값의 변화를 실시간으로 추정·보상하는 퍼지추론기를 구성하므로써 회전자 저항의 변화에도 최적의 효율 및 성능을 가지는 보완된 벡터 제어 기법을 개발하였다.

This paper presents the 2nd excitation control of the wound-rotor induction motor with Fly-wheel. In the wound-rotor induction motor, the primary power is controlled by AC excitation which used the secondary power conversion. Based on theory, this paper describes the dynamic response analysis of the wound-rotor induction motor with Fly-wheel and Simulation using MATLAB is performed to verify the proposed control method.

This paper describes a speed sensorless algorithm for vector control system with compensated stator resistance and rotor time constant of induction motor using a model reference adaptive system(MRAS). The system are composed of two MRAC, one is a rotor speed estimation and a stator resistor identification by back-EMF observer, other is used to identify rotor time constant by magnetizing current observer, so that the estimation can be cover a very low speed range with a robust control. The suggest control strategy and estimation method have been validated by simulation study. In the simulation using Matlab/Simulik, the proposed speed sensorless vector control system are shown to operate very well in spite of variable rotor time constant and load fluctuation.

Using Observer, on the sensorless vector control system is a novel techniques for modern induction motor control. In this paper, a speed estimation algorithm of an induction motor using an extended kalman filter was proposed. Extended kalman filter can solve the problem, that have steady state error of estimated speed in flux and slip estimation method. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator current and DC link voltage. In order to confirming above proposal, computer simulation carried out using Matlab Simulink and show the effectiveness of the control drives for induction motor speed estimation.

This paper describes a design method of grid-connected photovoltaic power generation systems with three phase inverter. A 3-phase 50kW photovoltaic power generation system including a DC/AC inverter is designed and made in order to investigate the system performance for grid connection. Also the control scheme of a three phase current-controlled PWM inverter is presented by using d-q transformation. The experimental waveforms show that the proposed system has stable behavior with an unit power factor in utility-interactive operation.

This paper represent about design of the controller for battery of Guide-Eye Sign Lamp with traffic auxiliary system for power supply using solar cell. Simulation is represents V-I and power characteristic by Mathematical & Design Center 6.3 & Qnet 2.1. This system is successfully operating with high clearness lights.

In this paper, the inverter spot welding system with high efficiency via an instantaneous power control is presented. In spot welding, instantaneous power control is utilized in order to attain less spatter and high welding performance. Also we proposed a PI controller for spot welder system using Evolution Strategy(ES) with varying search space. ES with varying search space which depends on fitness values at each generation is used to tune PI control parameters

Generally the control method of wire feeding motor in welding machine has been used full-wave phase control method. The fire-angle control generates low frequency speed ripple, and it causes the output current ripple. So it results in the variation of welding condition and low welding performances such as spatter generation and bead state. For the purpose of welding performances improvement by speed controller in wire feeding motor, in this paper the constant speed control method for welding machine is proposed. The proposed system is composed of speed control loop and current control loop. As a result of experiment by using proposed constant wire feed experiment by using proposed constant wire feed speed controller, the output voltage and current waveform and metal transfer are maintained stably. And moreover the number of instantaneous short circuit occurrence is reduced remarkably.

As the industry has been growing rapidly, the problem of environmental pollution has been on the rise seriously. In this paper, we used solar cells at the power supply unit of the equipment, which has been sold at present, for measuring the quality of water in order to complement the problem. Also, to get rid of the inconvenience that the examiners must go to the job site, check and collect the polluted water we set the goal at designing the water pollution alarm system which measures the quality of water automatically using one-chip microprocessor and materializing the program.

본 논문은 다양한 분야에 적용이 가능한 고압 직류 전원장치를 개발에 관한 것이다. 개발된 이 장치는 soft switching 기술을 이용하여 인버터의 전력소자가 switching 때문에 발생하는 손실과 EMI를 감소시키기 위하여 영전압 스위칭(ZVS; Zero Voltage Switching) 방식을 채택하였다. 이러한 고주파 인버터의 구동방식을 단일 Chip 제어기로 쉽게 구현할 수 있는 영전압 스위칭 위상전이 제어 직렬 공진형(ZVS PSC-SRI; ZVS Phase Shifted Control Series Resonant Inverter)으로 선택하여 제어기의 신뢰도를 높였고 장치의 고효율화(90%이상) 확보와 장치의 소형화뿐만 아니라 실용화를 위한 저가격화를 절충할 수 있는 방법을 중점적으로 연구하였다. 본 논문에서 고주파 고압 직류 전원 장치의 구성 및 설계, ZVS PSC-SR 인버터의 설계 그리고 고주파 고압 변압기의 설계에 관한 내용을 자세히 설명하고 제작된 고주파 고압 전원장치의 실험결과 및 고찰을 기술한다.

High power density on-board power supply is implemented by using flat transformer. In the high frequency switching converters, large leakage inductance increases the switching stress and duty cycle loss, which sometimes limits maximum switching frequency. The flat transformer is designed by using special core structure, which has very low profile and low temperature rise since the thermal loading is spread evenly over a larger area. 100W, 3.3V output on board supply is built and tested and 50.7W/$\textrm{inch}^{3}$ power density is achieved.

본 논문에서는 12펄스 위상제어 정류기 및 수동 필터와 능동필터로 구성된 KCCH 싸이클로트론 전자석용 고정밀, 고안정 전류 전원장치를 위한 각 구성 부분의 제어 및 설계 특징은 다음과 같다. 12펄스 싸이리스터 컨버터의 출력전압 제어를 위하여 아날로그 phase-locked oscillator 점호방식과 함께 부하에 비해 빠른 동특성을 가지는 내부 전압제어 루프를 구성하여, 입력전원과 변압기의 불평형에 의해 발생하는 저차고조파를 줄어들게 하였다. LC 수동필터와 MOSFET으로 구성된 능동필터를 직렬로 연결하여 출력전압 리플을 허용치 이하로 낮추었다. 12펄스 컨버터 출력전압 리플의 최대 peak-to-peak값이 0.1% 이하가 되도록 수동필터 값을 설계하였으며 설계과정을 제시하였다. 16bit D/A와 A/D에 의해 디지털로 제어되는 pass bank MOSFET 레귤레이터는 출력리플의 slow drift 제어와 설정치 값의 정확한 제어를 가능하게 한다. 또한 MOSFET는 전압 구동형 소자이며 turn-on 전류 도통 시에 양의 저항계수를 갖기 때문에, 첫째 전류 구동소자에 비해 간단한 구동회로를 가지며, 둘째 소자의 병렬 연결이 용이하다는 이점을 갖는다. 본 논문에서는 전류 전원장치 각 부분의 설계에 대하여 상세한 설계결과를 제시하며, 실험결과를 통하여 제안된 설계방식의 우수한 정적 및 동적 특성을 입증한다.

The conventional $CO_2$ inverter arc machine has constant voltage output characteristic and uses constant wire speed controller for welding current control. By adoption of PWM inverter to the welding machine, the spattering was reduced rather than the thyrister arc welding machine or AC arc welding machine. Moreover, by the high switching frequency, the output reactor size could be reduced evidently. Recently, the studies on optimal voltage and current waveform for the welding performance improvement have been studied. In this paper, a new instantaneous output current control scheme during the short circuit mode was proposed and showed the capability of arc stability improvement and the reduction of spatter generation.

The application field of photovoltaic system has been increased widely. In the application of photovoltaic system, the utility interactive photovoltaic system(UIPVS) has benefits of not only the home energy saving in domestic system but also reduction of peak power which threaten the capacity of power plant equipment when the maximum power consumption is occurred in daytime. This paper represents the effect of the nonlinear AC load which connected to the UIPVS with parallel connection and introduces the active power filtering(APF) techniques to the UIPVS for the reactive power compensation. The enhancement of source side power quality using APF algorithm is verified using simulation.

A new of the automotive High Intensity Discharge(HID) lamp ballast systems is proposed. Proposed scheme is consisted of the high frequency DC-DC converter and low frequency DC-AC inverter as same as conventional HID ballast system. But this system separates ignition voltage from dc link voltage, which results to used the lower voltage rating power devices for HID lamp ballast system compared with conventional system. As a result, proposed system has a lower cost and higher efficiency.

In this paper, we attempt to control the pressure between two specimens using a servo gun in the resistance spot welding process. Servo guns have some advantages over pneumatic guns in that the fast response, the precise position control, and the accurate torque control are assured by virtue of the servo motor control. To demonstrate the practical significance of our results, we present some experimental results..

저궤도 인공위성 전력계 시스템에서 배터리는 식(eclipse) 기간 동한 부하에 전력 공급을 담당한다. 따라서 배터리는 전체 위성의 수명과 성능을 결정 짓는 가장 중요한 요소이다. 이러한 배터리의 신뢰성을 향상시키기 위해, 다이오드를 사용하여 배터리를 병렬로 구성하는 시스템이 사용되고 있다. 본 논문에서는 이러한 배터리 병렬 구조 시스템의 성능 검증을 위해 배터리의 충방전 특성을 효율적으로 시뮬레이션 할 수 있는 Functional 모델링의 방법을 제시하고, 그 모델을 배터리 병렬 구조 인공위성 전력계 시스템에 적용하여 배터리 병렬 구조에 의해 생기는 배터리 불균형과 그 원인을 확잉하고 나아가 대안을 제시하였다.

This thesis aims at developing of a digita governor system for the steam turbine generator on the Buk-Cheju Thermal Power Plant of KEPCO. The steam turbine generator of the Buk-Cheju Thermal Power Plant is modelled. As a hardware platform, a triple modular system which is fitted 32-bit microprocessor of Motorola company to perform the digital governor system is used. The parameters of the PID controller algorithm in the speed control block is tuned on the basis of the estimated model.

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved zero voltage switching forward dc/dc converter is proposed. The proposed converter is constructed by using energy recovery snubbers in parallel with the main switches and output diodes of the conventional forward dc/dc converter. Due to the use of the energy recovery snubbers in the primary and secondary side, the proposed converter achieves zero-voltage-switching turn-off without switching losses for switching devices and output rectification diodes. The complete operating principles and experimental results will be presented.

With the advent of the high-speed microprocessor and DSP, the possibility of executing a control strategy in digital domain has become a reality. By the use of the DSP and microprocessor controller, many high power drive system may be enhanced resulting in the improved robustness to EMI, the ability to communicate the operating conditions and the ease of adjusting the control parameters. But, the digital controller using DSP or microprocessor is not applied in the high frequency switching power supplies, especially full bridge DC/DC converter. So, this paper presents the method and realization of designing a digital-to-phase shift PWM circuit for full digital controlled full bridge DC/DC converter with zero voltage switching. The operating principles, simulation and experimental results will be presented.

This paper introduces a novel zero-voltage switching (ZVS)) pulse width modulation (PWM) active clamping dc-to-dc boost converter. This technique presents ZVS commutation without additional voltage stress and a significant increase in the circulating reactive energy throughout the converter. Therefore, all of the losses for the switches are minimized, and high power density system can be realized. The characteristics are verified through simulation and experimental results.

A new integrated single-stage zero current switched(ZCS) quasi-resonant converter (QRC) for the power factor correction(PFC) converter is introduced in this paper. The power factor correction can be achieved by the discontinuous conduction mode(DCM) operation of an input current. The proposed converter has the characteristics of the good power factor, low line current harmonics, and tight output regulation. Furthermore, the ringing effect due to the output capacitance of the main switch can be eliminated by use of active clamp circuit.

A new multiple-output dc-to-dc converter based on a switched capacitor circuit is proposed. The proposed converter offers multiple outputs that can be individually regulated by a direct output voltage feedback or indirect cross regulations. The performance of the new converter is demonstrated using a 10W experimental converter that delivers 5V/1A output and 3.3V/1A output from a 10∼15V input source.

Manufacturing TGV-Korea, international standards and TGV-standards should be strictly applied in order to insure the normal operation and the safety of passengers in a train service. This paper presents a development of 800W DC-DC converter for the reading lamp of TGV-korea. The converter is designed for satisfying the regulations of international standards and TGV-standards regarding the burning-in test, the vibration test, the electro-magnetic emissions test, etc. As an experimental result, the maximum efficiency is obtained as 92.3[%] at normal input voltage and output power.

An integrated zero current switching(ZCS) quasi-resonant converter(QRC) for power factor correction and high efficiency with single switch is proposed in this thesis. Boost integrated circuit operating discontinuous conduction mode(DCM) and QRC are used for power factor correction and reducing switching loss, respectively. A prototype converter has been designed and experimented. At rated condition, the THD in the input current waveform of this prototype has approximately 18%. The efficiency is obtained about 70%, the power factor is about 0.985 as well. Therefore, the proposed converter is suitable for a low power level converter with operating switching frequency above several hundred KHz.

The conventional high frequency phase-shifted full bridge dc/dc converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate this problem, this paper provides a circulating current free type high frequency soft switching phase-shifted full bridge (FB) dc/dc converter with the modified energy recovery snubber (ERS) attached at the secondary side of transforemr.

A new isolated boost dc to dc convertor suitable for a low input voltage application is proposed. The proposed convertor features the low switch current stresses, the wide input voltage range operation, and the inherent inrush current protection characteristics, essential to design a low to high voltage conversion circuit. A comparative analysis and experimental results are presented to show the validity of the proposed convertor.

In this paper, author describe the simulation results concerning the period doubling bifurcation route to chaos of DC/DC boost converter under current mode control to show that it is common phenomena on switching regulator when parameters are improperly chosen or continuously varied beyond the ensured region by system designer. Bifurcation diagrams of periodic orbits of inductor current and capacitor voltage of DC/DC boost converter are plotted with sampled data at moment of each clock pulse causing switching on. DC/DC boost converter studied on this paper is modelled by its state space equations as per switching condition under continuous conduction mode. Current reference signal and capacitance are chosen as the bifurcation parameters and those are varied in step for iterative calculation to find bifurcation points of periodic orbits of state variables.

In this paper, Parallel operation of two DC-DC converters which we have ever done before need two CTs to do load current sharing. However, we have proposed a new method called ZCT method that can share load current with only a CT as doing parallel operation two converters with same converter capacity. To confirm parallel performance by a proposed DC-DC converter parallel operation method, we have done computer simulation and experiment. It is certain that we have showed to achieve two converters current sharing performance efficiently through simulation and experiment at result.

As utility pollution take a growing interest, ac/dc converter optimizing utility condition has been vigorously studied in decades. In this paper three phase DCM converter is analyzed and equations for average input currents are presented. Also relationships of voltage gain & duty according to angular velocity are presented and variable frequency controller is implemented using reset integrator which is designed in detail. In result power factor and THD characteristics of 3-stage and 4-stage operation ae compared respectively.

This paper describes a three-phase converter with high power factor using a scheme of discontinuous current mode(DCM). The proposed system can replace the conventional diode bridge with step-up chopper which is used as a converter for adjustable speed drive. In this system, the current of reactor is zero at turn-on instance because of operation in DCM, while the switch turns off at the instance of maximum current. A soft-switching scheme with lossless snubber was proposed. Therefore, a zero-voltage switching at turn off can be achived by lossless snubber and zero-current switching at turn on can be obtained by operating under DCM. A theoretical analysis and computer simulations with PSpice were done to verify the operation of the proposed system. Also a prototype of hardware system was built and tested for verifying the feasibility of proposed system.

An active power filter is used to eliminate harmonic currents. This paper applied the extension pq theory to harmonic currents compensation. An active power filter based on extension pq theory is more effective than pq theory in 3-phase unsymmetrical voltage system. When extension pq theory is used, the result of simulation present source current is not distorted. Pulse-width modulation method is CRPWM(Current-Regulated PWM).

In the PWM converter, PLL(Phase Locked Loop) is usually used as a tool which senses the angle of input voltage. This is sensitive to nois and needs additional hardware. In this work, we propose a sensorless control scheme of PWM converter using EKF(Extended Kalman Filter). EKF estimates a phase angle of input voltage from nonlinear state equation using measured phase currents. We control power factor and DC-link voltage utilizing the estimated phase angle. We demonstrate the effectiveness of the proposed estimation algorithm through simulations.

A single-phase PWM current source rectifier with a neutral leg is presented and throughly analyzed in this paper. This novel topology is implemented by adding an extra leg a step-down single phase PWM space vector modulation method to reduce the dc output voltage harmonics is proposed. The PWM pattern generation need a digital system. As compared with a conventional single-phase PWM rectifier, over 20% improvement of the total harmonics distortion in the output voltage can be obtained. Different SVM techniques are analyzed for this PWM rectifier and simulation result are presented.

A thyristor controlled shunt compensator, which is installed in the middle of the transmission line is adopted for controlling real power flow in a simple power transmission system. By means on the Fourier series representation of the thyristor switching action and the system parameters, the thyristor current equations are derived, which transmit the required real power of the simple power transmission system and inform the thyristor firing angle, the thyristor conduction angle, the power flows and the harmonic characteristics EMTP simulations at the various operating points show the dynamic characteristics of the thyristor controlled shunt compensator and correspond to the results calculated with the Fourier series representation.

In this paper, a method for controlling a single phase PWM AC/DC converter without any voltage sensors is proposed. In this method, the source voltage is estimated by sliding mode observer and input current is synchronized with the estimated source voltage. The source voltage is estimated by current error between the actul and the estimated current. The experimental results confirm the validity of the proposed control method.

Recently, it is increased to adopt inverter system to household electrical appliances, especially in ai conditioner and refrigerator. Inverter system is adopted for improving the efficiency. But Inverter system makes acoustic noise caused by switching frequency. In household electrical appliace, it is important to reduce acoustic noise. And in some cases it is possible to magnify the acoustic noise caused by switching, by system which may have different transfer characteristic. In this paper, random PWM method was adopted in inverter refrigerator using 8 bit microprocesso. We found useful PWM frequency and adoptation method.

A new control scheme is proposed suitable for the three phase PWM converter having abrupt load variation such as a crane. In the converter used in a crane, the peak value of source voltage varies instantaneously due to the abrupt load variations. Such a voltage variation degrades the performance of DC-link control of PWM converter. To overcome this problem, load variations should be detected and compensated properly. We propose a new method for detecting and compensating the load variations without the additional hardware. With the proposed scheme, load variations are detected by estimating the current of DC-link capacitor. The estimated current information is feedbacked to a current controller to improve the performance. Additionally, the variation of source voltage is compensated using feedforward controller. The performance of the proposed scheme has been verified through simulations.