This paper proposes a method of voltage control for three-phase multilevel H-bridge inverters with selective harmonic elimination (SHE) PWM The full-bridge configuration of H-bridge inverter cells enables voltage control with a fixed PWM pattern by means of phase shifting between the legs, which greatly simplifies the control while maintaining the harmonic elimination characteristics. The series combination of the cells in multilevel configuration can be exploited to further improve the hormonic elimination characteristics with proper phase shifting between the ceil volitage. A complexor-based control method is introduced to control the magnitude and phase angle of cell voltages that form three-phase multilevel output voltages. Simulation results show that the proposed method along with SHE PWM would provide satisfactory performance in spite of its simplicity.

Conventional variable-speed Induction motor drives with inverters are subject to detrimental effect of zero-sequence voltages, such a shaft voltage and bearing current. This paper presents a way of the suppression of the zero-sequence components in multilevel H-bridge inverters. First examined Is the inherent zero-sequence characteristic of the conventional subharmonic PW method. Then it is shown that the zero-sequence voltage can be eliminated with proper -selection of switching states with space vector modulation. Although this method alone restricts the linear modulation range of control, a combination of the proposed method and the minimum switching method appears to be effective in suppressing the zero-sequence voltage to minimum level while maintaining the linear control range.

This paper deals with the design of heat dissipation system using the forced air cooling method. It suggests the method of appropriately dividing the whole thermodynamic system into analytical subsystems and also presents the correspondent analytic or experimental equations to subsystems. The experimental results on the designed thermodynamic system for 400kw 1GBT inverter show the validity of the proposed design method in the steady state.

The electric power, regenerated while railway vehicles braking or running downhill, makes U line voltage rise and the feeding system may not be secure. In order to keep away from these kind of insecurity, the regenerative energy should be consumed by loads or transmitted to the AC side via certain devices such as DC/AC converters. This paper introduces the developed regenerative inverter for electric railway.

In this paper are described the indirect induction heated boiler and induction heated hot air producer using the voltage-fed series resonant high-frequency inverter which can operate in the frequency range from 20 [kHz] to 50 [kHz]. A specially designed induction heater, which is composed of laminated stainless assembly with many tiny holes and interconnected spot welding points between stainless plates, is inserted into the ceramic type vessel with external working coil. This working coil is connected to the inverter and turbulence fluid through this induction heater to moving fluid generates in the vessel. The operating performances of this unique appliance in next generation and its effectiveness are evaluated and discussed from a practical point of view.

This paper presents a novel hybrid type multilevel inverter in order to improve the waveshape of output voltage. The proposed multilevel inverter is consist of two full-bridge modules for level creation and one full-bridge module for PWM operation. The generated levels are total 11-level: 9-level by the level inverter and 2-level by the PWM inverter. The operational principles and analysis are explained and validity of the proposed system is verified through the experimental results using a prototype.

This paper describes two novel current fed high frequency resonant inverter can be used as the power supp]y for wax-sealing. This two topology can be obtained higher output frequency than switching frequency by composing modified unit inverter based on conventional half-bridge serial resonant inverter in parallel with input power source. also, By using time-sharing gate control method, this proposed inverter can not only realize the output control of dependence irrespective of the switching frequency using phase-shift but also reduce switching loss because it has ZVS function. Simulation results through the Pspice have demonstrated the feasibility of the proposed inverter. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

본 논문에서는 이중접속 방식의 멀티스텝 인버터를 인 용한 대용량 STATCOM에 관하여 동작원리 및 제어 방식을 기술하기로 한다. 기존의 12-스텝 인버터에 상간 변압기 및 간단한 보조회로를 이용하여 출력전압의 파형을 36-스텝으로 개선하였다. 이러한 방식의 인버터는 10Mvar$\~$30Mvar급 전후의 STATCOM에 적용하면 경제적이다. 2KVA급 STATCOM 시작품의 실험결과로부터 제안한 방식의 타당성을 입증하였다.

The push pull forward converter is a very suitable circuit for low output voltage, high output current applications with a wide input voltage range. All the magnetic components (output inductor, transformer, input filter) can be integrated into a single core. The integrated magnetics can reduce the number of the magnetic components. Developed the push pull forward converter rating are of 36 $\~$72V input and 3.3V/30A output. In this converter, the efficiency was measured by $76.4\%$ at full load and 82.95$\%$ at full load. The maximum efficiency is up to 83.$\%$ at 200kHz switching frequency, l1A output.

In this paper, a PC-based virtual measuring program for efficiency analysis of DC-DC converter is developed. Furthermore, a newly developed, highly accurate and reliable data acquisition system for DC-DC converter is presented. The virtual measuring system consists of two different types of monitoring and measuring system. Also, this paper give a full explanation for a LabVIEW realization of the measuring system for DC-DC converter.

Recently the PDP is the most remarkable media for a next generation display device. In this paper, we proposed the PDP dedicated DC-DC converter using a new soft switching method because the PDP has a lot of power dissipation so we need to develope. The proposed converter using one transformer has soft switching and a advantage to lower voltage stress in switch and also is predicted to have high power efficiency. we proposed the principles and theory using the zero voltage switching and verified the validity through a simulation.

In this paper, to analyze efficiency characteristic, one of important factors in design of DC-DC converter prototype, theoretically derived power loss of individual components generating in DC-DC converter and compared theoretical results with experimental results. For evaluation of results, active clamp type Forward DC-DC converter with synchronous rectifier was composed of experimental converter. Efficiency result measured in experimental converter was compared with theoretical efficiency result derived in this paper. In comparative results, a fact that derived theoretical value and experimental value comparatively correspond have been able to verify.

A new non linear, mean value, instantaneous following control technique to design half bridge converter is proposed in witch control principle uses characteristic that reset time of analog integrator is inverse proportion In input voltage. It is Important characteristic that compensation and follow-up control time are same with switching frequency. Is completed in one cycle that base control frequency. Have excellence characteristic that follow in order instruction value exactly stationary state as well as transient state. Half bridge converter that apply this control principle can know that have stabilize and excellence characteristic. This technique is verified through an experiment, and know that experiment result and theory agree well.

In this paper, resonant Characteristics of the soft switched asymmetrical half bridge converter is analysis. The operation principle for proposed converter is explained in steady state and its circuit is analyzed by means of equivalent circuit. Experimental results carried out on a system prototype are included in this paper.

We considered of the efficiency for the Buck+Half bridge converter This converter has advantages of applications for a low output voltage, a high output current and a wide input voltage. Developed the Buck converter ratings and the Half Bridge converter ratings are 36$\~$72V Input and 22V/5A output, 19$\~$24v input and 3.3V/30A output, respectively. Buck converter is operated with zero voltage switching process to reduce the switching losses. The 80.1 $\~$97.6$\%$ of the efficiency is measured at 18.4 $\mu$H output filter inductance of Buck convertor. In Half Bridge convertor, the 86$\~$96.4$\%$ of the efficiency is measured at 100kHz switching frequency with PQI core.

This paper proposes the single stage boost input type resonant AC-DC converter. Proposed converter uses the resonance between leakage inductance of the transformer and resonance capacitance. And it obtains high power factor more than 98$\%$ through continuous current mode pulse width modulation. To verify the validity of the proposed converter, operation principle In the steady state is analyzed and experimental results are presented.

In this paper new control strategy of series resonant converter system for control power supply is suggested. Frequency controlled series resonant converter system is robust to load variations because it is POSR(parallel output series resonant) type. And it provides stable output voltage by changing switching frequency to input voltage variations. Firstly, operation analysis about suggested series resonant converter system was carried. Then simulations using ACSL(Advanced Continuous Simulation Language) and experiments to actual system were carried to prove characteristics of suggested system.

A zero voltage soft switching inverter using active clamp is presented for induction heating application. This converter have long been attractive because of its simplicity, high efficiency, and low cost compared to other schemes. In addition to those merits, Input power factor can be improved with a variable frequency control. In this paper, it describe the control method and operational principle to improve a power factor with a single stage US converter using active clamp for induction heating application.

Switching Mode Power Supply(SMPS) is widely used in many industrial fields. Power factor improvement and harmonic reduction technique are very important in SMPS. In this paper, we propose the circuit applied Flying Capacitor Snubber for improving power factor of boost converter on fast switching state. Snubber circuit consists of a inductor, two diodes and a capacitor. The losses of switching are reduced by inserting a snubber inductor in the series path of the boost switch and the rectifier diode to control the di/dt rate of the rectifier during it's turn-off. Prior to actual experiment, the circuit analysis Is implemented by PSPICE simulation.

DC-DC converter for KOMPSAT-2 has been developed to meet the converter requirement in the PCU equipment specification. The function and capability have been verified by the simulation, functional and environmental test during the KOMPSAT-2 development period.

In this Paper, we report the experimental results of the Forward-flyback U-U converter with current doubler and synchronous rectifier. The experimental converter, that has a output voltage 3.3V, output current 20A, maximum power of 66W, switching frequency of 290kHz and input voltage range of 36-75V, has been successfully implemented. As a result, in the entire voltage range the measured full load efficiency was above 85$\%$, and the output voltage was regulated at 3.3V within $\pm3{\%}$ tolerance.

Recently, Research that output voltage control using several control methods to dc-dc converter that is non-linear system is gone. This paper describes control algorithm of the Buck type DC-DC converter using neural network controller We conform a rightness theoretical analysis by comparing a theoretical values, simulation values obtained from simulation tool and experimental values obtained from experiment. the neural network controller got better special characteristic than the hysteresis controller, This paper is thought to be applied to several power conversion system use neural network controller.

Korea Multi-Purpose SATellite (KOMPSAT) uses software-controlled unregulated bus system In which the main bus is directly connected to a battery and the duty-ratio for PWM switch is generated by the on-board satellite software algorithm. In this paper, we propose a new power-stage circuit that can be available for modularization of a solar array regulator(SAR) which is used in the KOMPSAT. The operations at each mode and current sharing characteristics of the power-stage are analyzed and verified by simulation and experiments on a prototype converter.

In this paper, we propose a new diagnosis method of DC/UC converter aging. The method is based on parasitic resister change with aging process. we apply to on-line diagnosis of DC/DC converter because of observing not a device but a system. We present the mathematical analysis and experimental study.

The leakage inductance of the High frequency Transformer(HFT) in the flyback topology can be used an inductor of the Low Pass Filter(LPF) to reduce ripple and ripple noise in the output voltage. But, the values of leakage inductance and magnetizing inductance in the HFT are within $\pm20[{\%}]$). And the operating temperature of the HFT increased by the leakage inductance. Therefore, the leakage inductance of the HFT in the flyback topology has minimum and the LPF has non-polarity ceramic capacitor in the output stage. In this paper, the LPF in the flyback topoBogy takes PCB capacitor using double layer of PCB without non-polarity ceramic capacitor. Its experimental results show the reduced ripple noise and the reduced ripple in the output stage.

This paper describes an AC voltage regulator using AC chopper and auxiliary transformer which is series connected with main input. It has many advantages such as fast voltage control, high efficiency and low THD. A detail study of step down AC voltage regulator is described and two kinds of novel step-up/down voltage regulator for AVR are proposed. The operation principle and PWM method of the proposed regulator are described. Experimental results show that it can be used as AC voltage regulator for special purpose very efficiently.

In this paper, a new self-oscillated type high voltage charger controller circuit is proposed, which has variable constant current source characteristics to improve charge characteristic of charger roller. The proposed control method enables high quality printing characteristics regardless of the circumstance change such as ambient temperature or humidity by changing the current reference signal. To verify the proposed control method various experiments are performed.

In a motor driving, the current rate is directly related to the rate of a switching device and in cost reduction, the parallel switching operation is the alternatives because it has the smaller current rate through current division. There are many investigations for the parallel switching operations to equaling the current division. However it remains many problems for practical usage. The reason is that the switching characteristics are mainly relied on the different saturation voltage of each device etc. and these factors are not altered by circuit designer. In order to compensate this problem, a proper resistance is experimently inserted to the switching device. But this method can not be the optimal solution. Therefore this paper proposes a new parallel operation which uses a parallel phase winding to remove the traditional effect of switching device such as saturation voltage according to the division of current. Also the reliable and stable driving is improved through experiments and the detailed principles.

In this paper, a novel PFC AC / DC converter is presented to be appropriate for AC PDP's power driving system. The conventional PFC AC / DC converter has independent power stages and controllers for their switching respectively, which should have increased price, size on manufacturing and decreased its efficiency as well. So this advanced Single-Stage Power Factor Corrector is presented and verified through spice simulation.

Lateral MCT(MOS-controlled thyristor)소자의 전기 적 특성 Parameters의 변화에 따른 스위칭 특성을 조사하였다. 제안된 Lateral 구조의 MCT는 채널과 drift영역의 제작과정이 간편하여 ON저항이 작으면서, 대전류용인 전력소자의 제작이 가능할 것으로 사료되는데, SPICE와 MEDICI 시뮬레이션을 이용하여 drift 저항, transit time및 불순물 농도 분포에 따른 전기적 특성을 알아보았다. 불순물의 농도와 채널길이의 변수에 의한 소자의 저항을 변화시켜 U 특성과 주파수 특성을 조사하였는데, 저항이 커질수록 turn-off 시간과 ON 저항은 증가함을 나타냈다.

This paper deals with the development of IGBT stacks for cost reduction. One stack is consist of 4 IGBTS in parallel. In the high- and mid-power converters, IGBT stacks are more suitable than single IGBTS in the aspects of total cost of semiconductor devices, time for purchasing, maintenance, radiation of heat, size of surge absorber and harmonic filter, frequency characteristics, and etc.. Problems accompanied by parallel construction are studied and solved. Economical efficiency is discussed and field tests with 100kVA UPS are tarried out to verify the validity of the developed IGBT stacks.

이 논문은 고리 $\#$1 원자력 발전소를 기준 발전소로 하여 개발되고 있는운전원 교육용 가상 시뮬레이터 의 일부로서, 제어봉 제어계통 모델링에 대한 내용을 제시하는 것이 주된 목적이다. 제어봉 제어 계통의 목적은 원자로 출력을 변화시키기 위하여 제어봉 집합체(RCCA)를 동작시켜 단기적인 반응도(Short Term Reactivity)를 조절하기 위한 것이다. 실제 발전소와 똑같은 제어봉 제어가 가능하면, 실제로 운전원이 가상 시뮬레이터를 통해서 모든 상황과 사고들을 대처하는 능력을 가질 수 있도록 설계되었다 본 논문에서는 고리 $\#$1 원자력 발전소 운전원 교육용 가상 시뮬레이터를 구현하기 위해 현재까지 설계된 제어봉 제어계통의 기능, 구성, 제어봉 제어에 대한 전반적인 내용을 제시하고자 한다.

Shorted-turns can have significant effects on a generator and its performance. Shorted-turn sensor for synchronous generator's field winding have been developed. One of effective method detecting inter-turn short circuits on round rotor winding is a method using sensor detecting. But the method needs duplicate design of sensor for characteristic change according to types and forms of generator Thus sensing skill without sensor depend on change of electric property in generator. For the reason, this paper presents shorted-turns phenomenon and the characteristic analysis of shorted-turns In synchronous generator by using 2-D finite element method(FEM).

The linear motor available for linear transition motion, because of its advantages, the motor design and its application have gradually increased, but the quantitative measurement system of thrust force has not been generalized. So, this paper proposes the modeling, computation method, and measurement system of linear thrust force in HB-type linear pulse motor. As the computation method of thrust force in linear motor is presented and the measurement system is designed, and manufactured, it would be verified that reliability of measurement method and measurement system, considering on and comparing the results of mathematical modeling with measured values of static thrust force and dynamic one.

To control the position, velocity and torque of the ultrasonic motor, a great variety of method are proposed such as the amplitude, phase difference, frequency and so on. In the case of phase difference method, it has some advantages: it can control the direction and velocity of rotation only adjusting the phase difference and it has wide control-band. During the USM driving on adjusting phase difference, its characteristic was transformed by the change of resonance-frequency of stator, which means that the resonance frequency is different according to the phase difference. Consequently, we need to set up the most suitable driving frequency according to each phase difference.

한전 전력연구원은 기준 발전소 시뮬레이터가 없는 고리1호기 원자력발전소의 현황을 고려하여 주제 어실은 없지만 고리1호기의 운전특성을 나타내는 전범위 시뮬레이터개발의 1단계로서 강사 및 운전원 모니터에 나타나는 Soft Panel 만으로 운전훈련이 가능 하도록 하는데 목표를 두고 원자력발전소 운 전원 훈련용 시뮬레이터를 개발 하였다. 본 논문에서는 상기의 개발내용 중에서 시뮬레이션 시스템 구성, 컴퓨터별 주요기능, 강사제어 프로그램, 운전원제어 프로그램, Simulation Diagram 화면, Soft Panel 화면, 시뮬레이터 연동 등에 대한 내용을 기술하고자 한다.

In this study, we design and implement the 20kVA TCSC(Thyrister Controlled Series Compensator) simulator It was tested on the KERI simulator The KERI simulator is a analog simulator for power system at the KERI power system division lab. It consist of many power system components, which are a 380V 5kVA generators, scale-downed transmission line modules, transformers, switches, FACTS(Flexible AC Transmission System) devices. In this paper, we present the design and implementation of 20kVA TCSC simulator and its basic test results.

KERI simulator is a analog simulator for power system at KERI power system division lab. It consist of many power system components, which are a 380V 5kVA generators, scale-downed transmission line modules, transformers, switches, PACTS(Flexible AC Transmission System) devices. As a FACTS device module, 20kVA TCSC(Thyristor Controlled Series Compensator) module was designed and implemented. In this paper, we present the design and implementation of TCSC control hardware for KERI simulator

In this paper, systematization design method by analogical Interpretation which is profitable in the compatability and standardization of developed products and is useful of reducing construction time and price was introduced. Systematization design based on analogical interpretation is a method which systematizes each characteristic with mathematical description in order to make variable design parameters correspond with the terms desired. In this paper, after choosing a differential transformer as the sample for design components each characteristic was expressed mathematically by analogical interpretation and miniaturized ones were manufactured by similarity factors. The relationship between input voltages of an actual differential transformer and the model and output voltages occurred by the change of the displacements in operational axis was shown.

This paper presents a non-electrical isolated Prototype of N+X redundant UPS with two-quadrant converter. Proposed topology has multi-functions of battery charge and discharge regulation, operates with a near unity input power factor, compensates unbalanced voltage on U bus capacitors, and regenerates the circulating active power among the inverters into battery or grid. And furthermore, this system adopts a novel wireless parallel operation algorithm of N+X redundant UPS system with no control interconnections. Simulation and experiment results are provided in this paper to prove the validity of proposed topology and wireless control algorithm.

TOA(Time of Arrival) 및 TDOA(Time Difference of Arrival)경우 무선국의 시간동기화를 위해서 고도의 기술을 요구하고 있으며, 시간동기오차에 따른 위치검지의 정밀도가 낮아지는 문제가 있어 이를 극복하기 위하여 위상차(PDOA)를 이용한 새로운 열차검지기법의 제안에 따른 구현을 위하여 H/W의 설계에 대하여 기술하고자 한다 본 시스템은 전과의 전달 속도($\lambda$)를 응용하여 기준 주파수인 1.5MHz를 송신 시스템과 수신 시스템의 기준 주파수와 비교하여 그 위상의 차이를 비교하여 지연된 시간을 구한 후 이를 거리로 환산하는 시스템으로서 H/W와 S/W로 구분하여 구현 $\cdot$ 설계되는데 본 논문에서는 H/W설계에 대하여 기숙하였다.

Need of power stability, reliability is increased, as using of sensitive: nonlinear load are increasing. Therefore, Power Quality Problems become the center of public interest. Many kinds of algorithms have been studied for monitoring of Power Quality Problems. Monitoring algorithms of using RMS, FT and the others are easy to applicate to system. But, it is not enough to monitor all of Foyer. Quality problems. Wavelet Transform is more proper to applicate. so, This paper presents measurement system using discrete wavelet transform.

Proposed Hybrid System is composed of phase leading capacitor banks, LC passive filters and active power filter. The passive power filter in parallel connection eliminate the 5th and 7th harmonics. The Variable capacitor banks correct the most of power factor, and the active power filter takes charge of remainder,

본 논문은 계통상의 사고나 다양한 전력변환 장치들의 사용증가로 인한 전력품질의 저하의 계측과 분석에 관한 연구이다. DSP 프로세서를 사용하여 전력품질을 분석하며 분석된 data는 특정 서버에서 관리할 수 있도록 모니터링 전용 프로그램을 구성하여 일정기간 동안의 전력품질을 분석한다. 계측센서를 이용한 data를 제작된 DSP 보드를 통해 실효값으로 계산하고, 전력품질 Indices와 비교 분석하여 특정 서버에 저장하고, 전력품질 저하 대책을 위한 분석 자료로써 활용한다.

Electrical power in satellite system should persistently satisfy specified power requirement even though that happen the failure of solar array string or battery cell during the mission operation. In this study, the solar array and battery of GEO Communication Satellite with 3kW capacity are designed, and energy balance analysis according to power operation mode are performed to meet specified power capacity at the transfer orbit

This paper describes a new Sag-Swell generator for the test of custom power devices such as UPS, DYR, DSTATCOM, 5575, etc. The proposed science has good features of simple structure, high reliability, wide range of Sag and Swell variation, and easy control. Outage, harmonic distortion, notches, and voltage unbalance also can be generated. The operation principle of the proposed scheme is described and verified through simulations.

실시간 시뮬레이션이란 시뮬레이션 모델의 시간진행을 실시간에 기반하여 수행하는 시뮬레이션을 말한다. 이러한 시뮬레이션은 가상 운전 교육 프로그램으로 자주 사용되며, 실제로 이를 이용한 교육 훈련 프로그램이 많이 개발되고 있다. 발전소와 같은 대규모 시스템에서는 서로 다른 계통별로 나누어 시뮬레이션 모델링 후 하나의 시스템 안에 통합 시키는 방법으로 사용한다. 본 논문에서는 실제 고리 $\#$1호기 원자력 발전소의 상태와 유사한 시뮬레이터 개발을 통하여, 운전원에게 가상 시뮬레이션 교육용 Simulator로 제작되었던 일부 계통인 Nuclear Instrumentation System에 관련하여 개발된 사례를 서술하고 있다.

This paper presents a simple electronic stater for single phase induction motor(SPIM). To obtain a starting torque, the phase angle of the auxiliary winding is controlled using simple gate trigger control circuit. Because of this electronic stater circuit consists of some passive element and switching device, it is simple and robust. The experimental result shows some good results, and verifies the proposed electronic starter.

PV model is presented based on the shockley diode equation. The simple model has a photo-current source, an single diode junction and a series resistance and includes temperature dependences. An accurate PV module electrical model is presented, matching with boost converter MPPT strategy and demonstrated in Matlab for a typical general purpose solar cell. Given solar insolation and temperature, the model returns current vector and MPP.

본 논문에서는 비선형 단상부하에 의해 발생하는 전류 고조파를 보상하기 위한 단상능동전력필터의 제어방법을 제안한다. 측정된 부하전류에 시간지연을 주어 가상의 두 번째 상을 만들어서 단상시스템을 두 축을 갖는 시스템으로 만들어 복소계산이 가능하게 한다 기존의 방법과 달리 저역통과필터의 지연특성을 고려하여 필터를 통과한 지연된 위상을 가진 정현파를 가상의 상으로 이용하였다 두 개 의상이 존재하므로 순시로 무효전력을 구할 수 있게된다. 본 논문에서는 회전좌표계를 사용하여 순시계산을 하였고, 부하전류만을 검출하여 보상전류 지령치를 구하였다. RL부하에 대한 실험을 수행하였고, 이러한 실험을 통하여 제안된 제어법의 유효성을 입증하였다.

This paper presents an instantaneous space vector modulated voltage source type three-phase soft-switching PFC rectifier using a single auxiliary resonant DC Link snubber for alternative energy utilizations. in the first place, the operating principle of an active auxiliary resonant DC link snubber circuit is described including its unique features. In the next place, the simulation analysis of three-phase soft-switching PWM rectifier is implemented, and the operating performances or the three-phase voltage-fed PWM rectifier treated here, which can operate under the conditions of sinewave line current shaping and utility power factor are evaluated and discussed on tile basis of this simulation results.

Today we have excellent motor drive system using high frequency carrier PWM control voltage source inverter in the other hand, we have met serious problems caused by high frequency switching. PWM Cyclo-converter called Matrix converter is expected as the new strategy Possible to improve these problems and add some more convenient features suitable for new drive system. in this Paper, we will introduce the background, features and outline of this converter, and additionally introduce some remarkable activity on this converter

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge-resonant snubber which is used for power conditioner such as solar photovoltaic generation and fuel cell generation. The experimental results of boost chopper fed ZVS-PWM DC-DC converter are evaluated. In audition to its switching voltage and current waveforms, and the switching v-i trajectory of the power devices are discussed and compared with the conventional hard switching DC-DC converter treated here. The temperature performance of IGBT module,, efficiency, and EMI noise characteristics of this ZVS-PWM DC-DC converter using IGBTs are measured and evaluated from an experimental point of view.

In this paper, a full bridge edge-resonant zero voltage mode based soft-switching PWM DC-DC power converter with a high frequency center tapped transformer link stage is presented from a practical point of view. The power MOSFETS operating as synchronous rectifier devices are implemented in the rectifier center tapped stage to reduce conduction power losses and also to extend the transformer primary side power MOSFETS ZVS commutation area from the rated to zero-load without a requirement of a magnetizing current. The steady-state operation of this phase-shift PWM controlled power converter is described in comparison with a conventional ZVS phase-shift PWM DC-DC converter using the diodes rectifier. Moreover, the experimental results of the switching power losses analysis are evaluated and discussed in this paper. The practical effectiveness of the ZVS phase-shift PWM DC-DC power converter treated here is actually proved by using 2.5kW-32kHz breadboard circuit. An actual efficiency of this converter is estimated in experiment and is achieved as 97$\%$ at maximum.

This paper presents a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control scheme DC-DC power converter, which can be used as power conditioner fur small-scale fuel cell power generation system. Using full-bridge soft-switching DC-DC converter topology makes possible to use low voltage high performance MOSFETs to achieve high efficiency of the power conditioner. A tapped inductor filter is implemented in the proposed soft-switching converter topology to achieve soft-switching PWM constant high frequency operation for a wide load variation range. to minimize circulating and idling currents without using additional resonant circuit and auxiliary power switching devices. The practical effectiveness of the proposed soft-switching DC-DC converter is verified in laboratory level experiment with 1 kW 100kHz breadboard setup using power MOSFETs. Actual efficiency of 94-96$\%$ is obtained for the wide load range

Photovoltaic(PV) array, which is generally installed outside, has the possibility to be damaged by high voltage due to lightning. Because the surge characteristics of PV array have not b eon fully Identified yet, there is a very important issue whether PV array should be connected with ground or not. In this paper, a basic model of PV array is provided considering the PV cell's barrier capacitance and ground capacitance for analysis of surge characteristics.

This paper presents a new motor design well suited for an advanced exercise bike. The advanced exercise bike setup high demands for performance and physical dimensions, which is high torque, wide speed range and a diameter/length ratio around 5. These requirements makes the new motor design called an E-core Transverse Flu Machine (ETFM) vev interesting because the segmented design of the stator and rotor poles enables high diameter without increasing the flux-path and since the ETFM is similar to the switched reluctance motor, high torque and wide speed range is possible. The design of the ETFM can be peformed using a developed design program, which is also introduced in the paper. A prototype of the exercise bike with the ETFM and a classical H-bridge converter with analog current control is constructed for verification of the concept.

The current paper presents the design and implementation of a low-profile dc-to-dc converter developed as a power supply for the sustain driving: circuit inside large-area wall-mount ac PDP application systems. Details on the design and implementation of a 500 W prototype dc-to-dc converter, miniaturized within a 230 mm$\times$ 130 mm area with a thickness of 25 mm while still achieving a 95 $\%$ conversion efficiency, are presented to demonstrate the feasibility and application potentials of the proposed low-profile dc -to-dc converters.

This paper proposes a novel UPQC(unified power quality conditioner) based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with EMTDC/PSCAD, assuming that the UPQC is connected with the 22.9kV distribution line. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules and can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance. The control strategy for the proposing UPQC was derived using the instantaneous power method. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems and can be utilized for the future distribution system.

In this paper describes the development testing results of high density High Voltage Power Supply(HVPS) that employ microwave TWTs. The HVPS consist of number of modules connected in series. A new design that adapt resonant circuit and high density pulse transformer to the high voltage modules makes the HVPS much more reliable. Also High voltage Solid-State modulation using fast switching devices(FET's) and the test results of modulator modules development are represented.

When ICP(Inductive Coupled Plasma type etching and wafer manufacturing is being processed in semiconductor process, a noxious gas in PFC and CFC system is generated. Gas cleaning dry scrubber is to remove this noxious gas. This paper describes a power source device, 2MHz switching frequency class 2kW RF Generator, used as a main power source of the gas cleaning dry scrubber. The power stage of DC/DC converter is consist of full bridge type converter with 100kHz switching frequency Power amplifier is push pull type inverter with 2MHz switching frequency, and transmission line transformer. The adequacy of the circuit type and the reliability of generating plasma in various load conditions are verified through 50$\Omega$ dummy load and chamber experiments result.

This paper describes a high voltage high power DC power supply which has the ability of pulsed mode operation. The power supply Is constructed with several series connected power converters based on modified multilevel converters. The modified multilevel converters are suitable for the protection of frequent output short-circuit. The output dc power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. The rising time of the dc load voltage is as small as several hundred microseconds, and there is no overshoot of the do voltage because the dc output capacitors keep undischarged state. Analysis, simulations, and experiments are carried out to Investigate the operation and usefulness of the proposed scheme.

본 논문에서는 2대의 다이오드 정류기에 부스트 컨버터를 이용하여 전류의 파형을 능동적으로 만들어 정현파의 입력전류를 얻는 새로운 방식의 고조파 저감방식을 제안한다. 제안한 당식으로 역률 1의 전원 품질을 얻을 수 있으며 입력측의 변동에 대한 출력전압의 조정도 가능하다. 또한 저감된 용량을 갖는 3상 오토 트랜스포머의 사용으로 기존의 $\Delta$-Y 변압기에 비해 KVA정격이 80$\%$ 절감되며 상간변압기도 필요 없다. 본 방식을 소형화와 고품질의 전원이 요구되는 통신용 정류기등에 적용하면 효과적이다. 제안한 방식의 동작원리, 제어 및 설계방법을 기술하고 1.5KW급 시작품으로부터의 실험결과를 제시한다.

The pantograph contact can be disrupted due to irregularities in the motion. The pantograph detachment prohibits the current flow and makes the system uncontrollable. During the pantograph detachment period, the control error are accumulated by the integral property of the controller. The output of the controller, therefore, can be induced to be an extremely large value. When the pantograph is reattached, the extremely large output of the controllers causes a very high overshoot (or under-shoot) of the line current and the DC-link voltage. This work proposes a new method for detecting the pantograph bouncing conditions and designs a controller considering such conditions based on the pantograph bouncing detector.

In this paper, to apply piezoelectric transformer for PDA backlight inverter, piezoelectric transformer using the composition which $Nb_2O_5$ added into PNW-PMN-PZT ceramics was fabricated as Rosen-type one with the size of $1165mm^3$. And their electrical characteristics were investigated with the variations of load resistance and driving frequency And then, the driving circuit for PDA CCFL(0.6W) which composed of the two MOSFETs connecting in series was manufactured using piezoelectric transformer, VCO and one-chip microprocessor. After driving for 25 min using the proposed circuit for PDA CCFL(0.6W), driving frequency of 214.4kHz, input voltage of 31.78 V and input current of 21.1mA were shown. And then, output voltage of 293.2 V and output current of 2.2mA were shown. At the same time, efficiency of 96.2$\%$ and temperature rise of $3.6^{\circ}C$ were appeared at the piezoelectric transformer.

본 논문에서는 상용무선망을 이용하여 각종 계측 및 측정 탑재장치에 의하여 측정된 데이터를 수집 및 전송하는 지상고정 초소형 위성과 이를 이용한 데이터 수집 시스템에 대하여 기술한다

Accurate acquisition of surface geometries such as machined surfaces, biological surfaces, and deformed parts have been very important technique in scientific study and engineering, expecially for system design, manufacturing and inspection. Two camera method keeps accuracy more than double than mechanical method. In this paper, we describe the processes surface data of teeth for automatic processing, transformation that changes to coping data of possible numeric data form and processed inlay teeth. As the result of the Inlay manufacture, which can process with high resolution, therefore we construct the automatic processing system that depends on manual

A semiconductor switch-based fast hi-polar high voltage pulse generator is proposed in this paper The proposed pulse system is made of a thyristor based-rectifier, DC link capacitor, a push-pull resonant inverter, a high voltage transformer. secondary capacitor, a high voltage IGBT & diode stacks, and a variable capacitor. The proposed system makes hi-polar high voltage sinusoidal waveform using resonance between leakage inductance of the transformer and secondary capacitor and transfers energy to output load at maximum of the secondary capacitor voltage. Compared to previous hi-polar high voltage pulse power supply using nonlinear transmission line, the proposed pulse power system using only semiconductor switches has simple structure and gives high efficiency

In this paper, the new zero-current-transition (ZCT) circuit cell is proposed. The main switch is turned-off under the zero current and zero voltage condition, and there is no additional current stress and voltage stress in, the main switch and the main diode. The Auxiliary switch is turned-off under the zero voltage condition, and the main diode is turned-on under the zero voltage condition, The resonant current required to obtain the ZCT is small and regenerated to the input voltage source. The operational principles of the boost converter integrated with the proposed ZCT circuit cell is analyzed theoretically and verified by the simulation and experimental result. Index terms - zero-current-transition (ZCT), zero-current- switching (ZCS), zero-voltage-switching (ZVS)

This paper deals with the frequency sensing methods at HVDC system. The objects of frequency information in HVDC system areto fire a valve and to control a frequency of AC network. Conventionally, there are two methods to measure a frequency of AC network. The first method is to draw out from the synchronous machine and the second method is from AC network. Two methods have advantages and disadvantage each other. For the extreme case of a receiving system of zero inertia (no generation), synchronous machine is essential. In this situation, the frequency information received from the synchronous machine shaft. However, the speed of synchronous machine is oscillated when a disturbance in AC network occurs, and HVDC may be oscillated due to an oscillation speed. To solve this drawback, in this paper, new frequency sensing method is proposed. A proposed method that is use a modified curve-fitting algorithm, has a robust characteristics against a harmonics and unbalanced faults. Consequently, A proposed method is verified by PSCAD/EMTDC Program and experimental test.

Usually, the thrust of a Linear Pulse Motor(LPM) is calculated by magnetic equivalent circuit modelling method. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force method. For calculating accuracy thrust by using these every method, tire thrust is calculated and compared by Lorentz Force method, Magnetic coenergy Method, and Maxwell correspondence forte Method. And that becomes Important factor at the comparison of each capacity and parameter of motor. So this study wants to compare and analyze measurement data and calculating data of the static thrust of LPM. and then we can get more accuracy method, calculating the static thrust of LPM.

The objective of this paper is to investigate the power spectrum of a three-phase and a two-phase RCD (Random Pulse Centered Displacement) PWM scheme. The two-phase or three-phase pulses of RCD-PWM scheme are mutually center-aligned as in SVM(Space Vector Modulation), but the common pulse center is displaced randomly from the middle of the period. To verify the validity of the proposed two-phase RCD-PWM scheme, the power spectra of the output voltage, the d.c link current in the inverter drives and the radiated acoustic noise are experimentally investigated. And, the performance of the proposed two-phase RCD-PWM scheme was compared and discussed with the conventional three-phase RCD-PWM scheme.

Investigated about topology of each component of transformer and material choice method and property in this paper. Component of transformer is bobin, winding, insulating paper, Varnish etc. And, experiment and investigated special quality by primary winding of transformer and composition of secondary winding. Investigated loss of transformer and EMI decrease method. Investigated method to select winding size that consider frequency.

A novel three-level DC/DC converter (TLC)for high power applications operating from high input voltage Is proposed. Its switch voltage stress can be ensured to be only one-half of the Input voltage. Nevertheless, since all input voltage is applied to the transformer primary side, it has good turns ratio. The driving method of each module is same as those of the conventional phase-shifted ZVS full bridge PWM converter (PSFB) and the zero-voltage-switching (ZVS) of the leading leg are achieved exactly in the same manner as that of the PSFB. Moreover, its three-level operation can considerably reduce the current ripple through the output inductor and it has no problems of the DC-link voltage unbalance. Therefore, it features a low voltage stress, high efficiency, low EMI, high power density, and small sized filter. To confirm the operation, validity, and features of the proposed circuit, experimental results from a 200W, 600V/DC-48V/DC prototype are presented.

본 논문에서는 THD 개선을 위한 단순한 구조의 단일 단 PFC를 제안하고 벅 컨버터에 적용하였다. 제안한 회로는 밸리-필 정류회로와 부스팅을 위한 인덕터를 결합하여 단일 능동 소자로 DC/DC 변환 과 PFC를 동시에 수행한다. 제안된 회로에서의 입력전류 모양은 입력전압조건과 PWM 스위칭 시간에 관계되고, 부스팅 인덕터에 의해 능동스위치 차단시간동안 입력 전류를 제어하여 THD를 개선한다. 부스팅 인덕터 채용에 따른 동작해석과 최적 THD를 위한 인덕터를 선정하고 100W출력 단일 단 컨버터를 설계, 제작하였다. 실험에 의한 측정된 결과로 제안된 컨버터의 타당성을 검증하였다.

This paper proposes a novel ZVZCS-PWM Boost Converter. It enables the main switch to be turned on and off with both zero voltage and zero current and the auxiliary switch to be turned on and off with ZCS, the rectify diode to be turned on and off with ZVS. Moreover, this converter is suitable for not on]y minority carrier device but also majority carrier device. The auxiliary resonant circuit of the proposed boost converter is placed out the main power path, therefore, there are no voltage/current stresses on the main switch and diode. The operation of the proposed boost converter is explained and analyzed theoretical and experimentally, from a prototype operating at 100kHz, with an input voltage rated at 50V.

In this paper, we report the experimental results of the novel Soft-Switching DC-DC converter and synchronous rectifier The experimental converter, that has a output voltage 3.3V, output current 20A, maximum power of 66W, switching frequency of 100kHz and input voltage range of 44-52V, has been successfully implemented. As a result, in the entire voltage range the measured full load efficiency was above 90$\%$, and the output voltage was regulated at 3.3V within ${\pm}3{\%}$ tolerance.

This paper presented practical details about control-loop design and dynamic analysis for a peak current-mode controlled asymmetrical half-bridge(ASHB) do-to-dc converter, Graphical loop gain method is used to design the feedback compensation and analyze the closed-loop performance of ASHB converter. The results of the control design and closed-loop analysis are validated by experiments on a prototype converter.

직렬연결형 다중레벨 컨버터(cascade multilevel converter)는 각기 절연된 DC전압원과 H-bridge 인버터가 한 단위를 이루고, 각 단위 인버터의 출력을 직렬 연결한 구조로서, 부하(전동기)에 정현파에 가까운 전압을 인가할 수 있는 시스템이다 각 H-bridge인버터의 DC전압원으로는 배터리 또는 커패시터등이 사용되는데, 일반적인 경우 각 H-bridge 컨버터의 입출력 파워가 틀려지게 되며, 따라서 DC전압간 불균형이 발생하게 된다. DC전압간 불균형이 발생하면 원하는 전압벡터를 정확하게 발생시킬 수 없게 되고, 고조파 하모닉이 만들어질뿐 아니라, 경우에 따라서는 DC전압원측에과 전압 또는 저전압 폴트가 발생할 수 있다. 본 논문은 N개의 H-bridge 인버터의 DC전압을 측정하지 않고, 전체 상출력 전압만을 측정하여 각 DC전압을 추정하고, 스위칭 패턴을 변경하여 DC전압을 평형화하는 방법을 제안한다. 모의실험을 통해서 알고리즘의 동작여부를 검증하였다.

Single winding self driven synchronous rectification(SWSDSR) scheme is based on an additional winding in the power transformer (auxiliary winding). It allows for maintaining the synchronous rectifiers on even when the voltage in the transformer is zero, which is impossible to do in traditional self-driven approaches. Its technique is verified to improve the efficiency by experiment. In this paper, there are compared self driven synchronous rectification(SDSR) with SWSDSR about the efficiency

A new single stage power factor correction(PFC) AC/DC converter based on zero voltage switching(ZVS) full bridge topology is proposed. Since the series-connected two transformers act as both output inductor and main transformer by turns, the proposed converter has a wide ZVS range without additional devices for ZVS. Furthermore, since there is no need to use an output inductor, the proposed converter features high power density. The proposed converter gives the good power factor correction and low line current harmonics distortion. A mode analysis and experiment results are presented to verify the validity of the proposed converter.

In recent years, the Photovoltaic(PV) industries have been Increasing steadily by an average of 30$\%$ per year. However, it is necessary to reduce PV module cost and to improve conversion efficiency to be promoted distribution of PV Japan, USA and Europe have been researching cost and efficiency of that. In this paper, we try to review diffusion status and policy of PV in these countries. From the results, we will intend to suggest a suitable future course for domestic PV distribution.

In recent years, the Photovoltaic(PV) industries have been increasing steadily by an average of 30$\%$ per you. However, it is necessary to reduce PV module cost and to improve conversion efficiency to be promoted distribution of PV Japan, USA and Europe have been researching cost and efficiency of that. In this paper, we try to review diffusion perspective of PV in these countries. From the results of this paper, we will intend to suggest a suitable future course for domestic PV distribution.

In this paper, an efficient modeling method of wind turbine system is proposed using multi-body dynamics. This method is based on representing a wind turbine system as a multi-body system with several rigid bodies. Also, simulation software WINSIM is developed to evaluate performance of wind turbine system. Simulation results show that proposed modeling method and simulation software is efficient and reliable

본 연구에서는 200kw급 풍력발전 시스템의 설치 지역으로 고려 중인 제주도 봉개동 지역의 풍황을 계측장비를 이용하여 7개월에 걸쳐 조사하였다. 측정된 자료들과 자체 제작 분석 프로그램을 사용하여 설치 예상 지역의 연간 예상 발전량 및 이용률 등과 같은 풍력자원을 분석하였다. 또한, 풍력자원 분석결과를 토대로 시스템의 설치 당위성 및 타당성의 판단기준의 하나인 발전단가 및 투자회수기간을 구하는 경제성 분석을 수행하였다.

This paper presents a study on the power factor improvement of the Wind turbine Generation System(WTGS) at Haeng-won wind farm in Jeju Island. Vestas WTGS named V47 as a model system is selected in this paper, and has 660 kW Power ratings. In this system, power factor correction is controlled by the conventional method with power condenor bank. So, model system at Haeng-won wind farm has very low power factor in the area of low wind speed, which is from 4 m/s to 6 m/s. This is caused by the power factor correction using power condenser bank To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter by IGBT switching device. finally, to verify the profosed method, the results of computer simulation using Psim program are presented to support the discussion.

In this paper, a novel nonlinear control method of the CVCF(constant voltage and constant frequency output voltage for the three-phase PWM inverter is proposed, which gives high dynamic responses at load variation as well as zero steady-state error. The experimental results are shown th verify the validity of the proposed scheme.

The stand alone PV system's stability and cost is influenced by a design method, as its application products are various. In order to systematize the the stand alone PV system's design method based on experience, this research settled the capacity computation method of PV module and battery and developed a simulator. And Its characteristic is confirmed by applying to PV street lamp design.

A use of micro processor having H-com functions is gradually increased, and this paper describes the digital servo controller applied to linear pulse motor The TMS320LF2407, made by TI(Texas Instruments Co.), is used as a arithmetic unit in control circuit, designed f3r motor drive and available for the implement of high performance and miniaturization. Also, it can allow the sufficient debugging and downloading into control board for independent operation. A current control in order to carry out a position control is of a digital current control mode, and its implement confirmed the servo control performance of position control.

This paper presents neural load torque observer tha used to deadbeat load torque observer and regulation of the compensation gun by parameter estimator. As a result, the response of PMSM follows that of the nominal plant. The load torque compensation method is compose of a neural deadbeat observer. To reduce of the noise effect, the post-filter, which is implemented by MA process, is adopted. The parameter compensator with RLSM (recursive least square method) parameter estimator is adopted to increase the performance of the load torque observer and main controller. The parameter estimator li combined with a high performance neural torque observer to resolve the problems. As a result, the proposed control system becomes a robust and precise system against the load torque and the parameter variation. A stability and usefulness, through the verified computer simulation, are shown in this paper

Dynamic Voltage Restorers (DVR)s are known as the best effective and economic means to compensate for voltage sags and swells [1]-[11]. This paper proposes a novel method to generate reference voltages synchronized with the grid whether the line voltages are distorted by a fault or not. The proposed reference wave generator (RWC) looks for the original wave forms from the corrupted line voltages and synthesizes the expected positive sequence reference waves for DVRs. There is no transient problem on the generated reference waves when the line voltages are distorted by the fault.

This paper discusses how to generate the reference compensation voltages in Dynamic Voltage Restorers (DVR) by use of PQR power theory Sensed three-phase terminal voltages are transformed to PQR coordinates without time delay. Since the reference voltages in PQR coordinates are do values, the voltage controller for DVRs is simple and easy to design. Proposed control method can be implemented by feedforward controllers or by feedback controllers. This paper verified the theory in the feedforward controller of a DVR by experiments.

In this paper, the virtual-reality system is tried to developed, which controls not only the sense of sight and hearing but also the sense of touch, In order to develope the sense of touch in this study, the stable tactual transaction-system, based on summing up the basic algorithm and theory, is embodied. The hardware of this system consists of the 6DOF haptic interface, a controller and a driver In the case of the software, the proxy algorithm is applied for the force-transaction and the mopping algorithm is used for graphic transaction. In addition to this, the imaginary-device driver is utilized for controlling the system and manager-class is also included in this system to manage the position-change and the like. Consequently, the proxy algorithm Is applied, which makes the system possible to be more stable and prompt with and imaginary object. Moreover, the impulse-algorithm is applied to work out a problem which the tactual transaction-period is different from the graphic transaction-period.

This paper focuses on a simple technique to reduced torque ripple in the direct torque control inverter for PMSM drive. It is actually impossible to raise the inverter switching frequency in the conventional system, although the hysterisis bandwidths for the stator flux and torque control are sufficiently diminished, because of the sampling Interval and the delay in estimating the flux and the torque In order to overcome the problem, the proposed method introduces a dithering technique into the conventional system by superposing triangular waves with high frequency and minute amplitude on the torque error. And the programable 3- stage lowpass filter is added instead of pure Integrator. Simulation results prove the feasibility of proposed strategy compared with conventional method.

자기 베어링을 구동하는 코일은 회전축의 위치 정보를 가지고 있다. 따라서 코일의 인덕턴스를 알 수 있으면 위치 센서를 쓰지 않고도 회전축의 위치를 알아낼 수 있다. 본 논문에서는 코일에 고주파 신호를 주입하여 인덕턴스를 알아내고, 이를 통해 회전축의 위치를 추정하는 방법을 제안하고, 그를 이용하여 자기 베어링의 센서리스 제어를 수행한다.

A reciprocating compressor with a rotary motor used in a refrigerator has low efficiency, because it has the large mechanical losses due to the crank mechanism. The linear compressor which has the free piston driven by a linear motor, was developed to increase the efficiency of compressor by reducing mechanical losses. The TRIAC has been widely used for controlling the piston, because it has simple structure. However, as it is able to control only stator voltage, it is very difficult to obtain good efficiency. Recently, PWM inverter which is able to control the voltage as well as the frequency, is applied to linear compressor drive system to overcome above problem. In this paper, the variations for efficiency and power factor of linear compressor are investigated by changing both the mechanical resonant frequency and electrical resonant frequency of linear compressor, and also the inverter frequency The optimum relationships between both resonant frequencies and the inverter frequency is derived in order to obtain the maximum efficiency and also good power factor.

IGBTS are widely used for the industrial inverters in the mid power range at low voltage (440V$\~$660V) application. Advantageous features of the device are simple gate drive and high speed switching capability. Due to these advantages the application of IGBTS is enlarging into the high power application. However, to increase the power handling capacity at lower input voltage level, the current rating in each bridge arm must be enlarged. Therefore the parallel operation of IGBT devices is essentially needed. This paper describes the feasible parallel structures of the power circuit for the mid & the high power inverters and introduces the important design condition for the parallel operation of IGBT devices. To verify feasibility of the IGBT parallel operation, the feature of several IGBT devices (EUPEC, SEMIKRON's IGBT) are investigated and the power stacks are implemented and tested with these devices. The experimental results show the good characteristics for the parallel operation of IGBTS.

This paper present an investigation of the influence on the PFC(power factor correction) circuit with characteristics variation of MPP (Molybdenum permalloy powder) core. The experiment results of the 1.5kW class Boost converter for PFC rectifier with the average current mode control are evaluated to verify the influence on the PFC converter with inductance variation of the MPP core. As a results, it is shown that the ripple of the inductor using a MPP core increase with output power of the converter.

Since 1960s. container shipping volume has increased dramatically and continuous on a trend of rapid growth, and so the number of containers handled at the port increases. In order to improve yard crane operating efficiency, the precise position measurement of the yard crane is important. This paper describes the method to measure the absolute position of yard crane using the output pulse of an encoder and infrared sensors. The crane position is calculated by counting the output pulse of an incremental encoder, which is mounted on the wheel in the crane. By the way, the wheel slippage on rail may cause some errors in crane position information obtained from encoder pulses, and the errors in the crane position information are compensated with infrared sensors. The performance of proposed method is verified on experimental results with the simulator of yard crane, the size of which is about 1/10 with the real crane.

This paper makes more stronger than original model about sending station fault and saves total construction cost to replace established six-pulse bridge by each six thyristor for DC-transmission. Also, varying of controller for sending station has a robust characteristics for harmonics and unbalanced faults. This paper is verified by simulation using EMTDC program. Comparing with the results of original model, this paper is proved superiority.

In this paper, the research trend and the sate-of-the-art of low cost motor drives are introduced with the recently increasing interest In various industrial applications, such as home appliance, hybrid electric vehicles, wind power systems, fuel cell systems, and etc. Based on this presented work, it is highly expected the power electronics technologies, which are accumulated through the last 20 years, can be effectively applied to actual application fields.

The a PWM VSI, the voltage distortion exists between the reference and output voltage. This distortion is caused by the intended blanking time and the inherent characteristics of the switching devices which are function of the operating condition. In this paper, the dead-time effects are analysed and a new on-line estimation method for a PMSM is proposed to compensate time varying dead-time effects

This paper presents the speed control of the surface-mounted permanent-magnet synchronous motors (SMPMSM) for the elevator drive. The elevator motor needs to be a compact and slim type. Essentially, the proposed scheme uses a vector control algorithm for a speed and torque control. This system is implemented using a high speed 32-bit DSP (TMS320C31-50), a high-integrated logic device FPGA (EPF10K10-Tl144-3) to design compactly and Inexpensively The proposed scheme is verified through digital simulation and experiments for a three-phase 13.3kW SMPMSM as a MRL(MachineRoomless) elevator motor ill the laboratory. Finally, experiment of the test tower was performed with a 48kW PWM converter-inverter system for a high- speed elevator .

The large synchronous motor for the pumped-storage plant(or SFC : Static Frequency Converter) has to be brought up to 100$\%$ rated speed and synchronized with the AC power network. Starting the motor from rest is achieved by switching current into the stator winding so that interaction between this stator current and the rotor flux will cause the correct direction of torque to be developed so that the motor turns in the required direction. Starting ranges of the synchronous motor are divided into three regions. The first region Is at standstill, the second that is called by the forced commutation is from standstill to 5-8$\%$ of rated speed, and the third, which is called by the natural commutation, is from 5-8$\%$ of rated speed to 100$\%$ rated speed. So this paper describes three regions of the control techniques of the pumped-storage synchronous motor drive.

In this paper, a new current control algorithm is proposed for four-switch three-phase brushless DC(BLU) motor drives, which are suitable for low cost applications. A current reference generation scheme is developed and Implemented to obtain high performance characteristics in the four-switch system, such as small torque ripple and fast dynamic speed/torque response. Moreover, the proposed scheme can successful1y eliminate the torque ripple during commutations, so that it can be expected that the four-switch system can be much more practically applied for the industrial application areas.

Generally, 2 phase excited brushless DC motor(BLDCM) operates only in the region of constant trapezoidal back-EMF on each phase. Therefore the efficiency decreases in comparison with 3phase excited BLDCM. This paper proposes the relation between the usage ratio of voltage and the change of fewer delivery of BLDCM according to extension of conduction intervals.

A strategy for a torque ripple reduction drive of single-phase SRM with high power factor is proposed. The drive for switched reluctance motor (SRM) is presented to achieve sinusoidal, near unity power factor input current with low torque ripple. The proposed SRM drive has no additional active switch. And a single-stage approach, which combines a DC link capacitor used as dc source and a drive used for driving the motor into one power stage, has a simple structure and low cost. The characteristics and validity of the proposed circuit is discussed in depth through the experimental results.

This paper presents the method of speed measurement for permanent magnet synchronous motor(PMSM) with the full-order observer using reduced-order state equation. This Is able to improve the operating performance at low speed. Therefore, by the proposed technique, a low resolution encoder can be used. Because it make the system improve the performance of speed response. The proposed method is verified to simulation and experiments.