• Journal of Power Electronics
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• 제15권1호
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• pp.246-255
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• 2015

This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.

• International Journal of Computer Science & Network Security
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• 제22권1호
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• pp.175-182
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• 2022

This work presents a simulation model for a specific UV disinfection system (UVDS) powered by a Photovoltaic System. The global UVDS also includes the electronic converters, Electronic Ballast, UV Lamp and Motor Pump. The equations that model the physical components' behaviour are connected to obtain a dynamic global model. The latter is converted in a Simulink/Matlab model, which allows to carry out simulation series concerning the entire UVDS. The physical parameters: the irradiation G and the temperature T, are considered as inputs. series of measurements carried out in order to show how these parameters affect the current, the voltage of the PVs and especially the value of the current of the UV lamp, on the other hand a study on the behavior and the evolution of the parameters of the motor pump such as the armature current, motor torque, speed of rotation and the water flow. The purpose of all this is to realize how important are the two parameters concerning the lamp current and the water flow because they are two very important factors to keep an adequate water quality.

• Journal of Power Electronics
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• 제14권5호
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• pp.957-966
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• 2014

Some of DC actuators used in home automation, office automation, medical equipment and automotive systems require a position sensor. In low power applications, the introduction of such a transducer remarkably increases the whole system cost, which justifies the development of sensorless position estimation techniques. The well-known AC motor drive sensorless techniques exploiting the fundamental component of the back electromotive force cannot be used on DC motor drives. In addition, the sophisticated approaches based on current or voltage signal injection cannot be used. Therefore, an effective and inexpensive sensorless position estimation technique suitable for DC motors is presented in this paper. This technique exploits the periodic pulses of the armature current caused by commutation. It is based on a simple pulse counting algorithm, suitable for coping with the rather large variability of the pulse frequency and it leads to the realization of a sensorless position control system for low cost, medium performance systems, like those in the field of automotive applications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.110-113
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• 2000

In general, speed control method of the elevator system has used motor pole change type or motor primary voltage control type. But it will change to vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control that primary current of the induction motor be controlled independently with magnetizing current(field current of DC motor) and torque current(armature current of DC motor). In this paper, by analyzing the effect of the time constant variation of rotor of the induction motor on the slip frequency type indirect vector control, a drive system for the motor will be constructed using a fuzzy slip frequency type indirect vector controller with fuzzy control method for estimating the vector time constant in the slip frequency type indirect vector control. The goal of this study is to enabling even more efficient speed control by constructing on elevator driver based on the newly developed drive system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권3호
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• pp.107-114
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• 2001

Electro-mechanical battery (EMB) consists of a high-speed fly wheel with an integral motor/ generator suspended on magnetic bearings and in an evacuated housing. Permanent magnet (PM) machines as the EMB motor/ generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper we present the comparison of conventional slotted and slotless ring-wound types, aimed at EMB and other high-speed drives. We firstly discuss the topology of each machine for this particular application. these machines are primarily designed as 1kW two-pole PM generator with the rated speed of 40000 rpm. the motoring torque of 0.51 Nm has to be enough to accelerate the flywheel to the rated speed. We then present the comparison of the open-circuit field, the armature reaction field and winding inductance. next we analyze the induced voltage and the developed torque per unit stack length and unit weight of different machines. Finally, we estimate and compare the losses and the efficiency at motoring and generating modes.

• 전기학회논문지P
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• 제64권1호
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• pp.7-13
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• 2015

This paper presents mathematical models for high speed permanent-magnet synchronous machine. The mathematical method with two successive steps is used to estimate design parameter as well as the output power. At first, mathematical model for a linkage flux problem is employed to calculate the number of winding turns and stack length of armature core. The magnetic circuit model for an induced voltage and the electric circuit model for a current are modeled. The output powers of the electrical generator were evaluated by the mathematical techniques. The results of this mathematical methods predict the specifications of the machine and can be applied in the design stage of the electrical machine.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.43-51
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• 1998

Most of fuel-injection system operated with mechanical methods are difficult to control the injection quantity and injection timing as well as injection rate exactly. Moreover high pressure injection scheme is never be realized with conventional one. On the other hand, serious air pollution can be lessened with injection system equipped with those functions. Therefore, electronically controlled Unit Injuctor(UI) appeared to satify above mentioned desires. However, it is still difficult that the most important part, especially solenoid valve, is analyzed precisely, because of the existence of complex combination of electromagnetics, electrics and dynamic problems. In this study, experimental and theoretical analysis are accomplished for understanding of solenoid valve characteristics and further its design. As the result, the follows are obtained 1) As the increase of wire diameter, the response time became shorter and optimal inductance existed in relative with the response time and wire diameter. 2) According to increasing input voltage, the traction force increased, otherwise the response time was shortened. 3) As the increase of armature stroke, the traction force decreased and the response time became longer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.809-811
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• 2004

A 1MW class superconductng synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS(High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30K($-243^{\circ}C$) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.688-695
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• 2017

본 논문은 파력 에너지 수집 장치에 사용할 수 있는 영구자석 선형 동기발전기의 특성 해석에 관한 것이다. 파력 에너지는 요요시스템과 같은 기구로 부터 얻어진다. 영구자석을 이용한 선형 발전기는 영구자석의 자력을 통해 별도의 전원공급이 필요 없고 유지 보수가 간단한 장점을 가지고 있다. 또한 높은 에너지 밀도를 갖는 희토류의 사용으로 영구자석 기기는 소형화 및 경량화가 가능하며 보다 높은 에너지 변환 효율을 얻을 수 있다. 영구자석 선형 동기발전기 특성 해석을 위해 2차원 극 좌표계 및 자기 벡터 포텐셜에 근거하여 영구자석과 전기자 반작용 자계해석을 수행 하였다. 해석 해를 이용하여 정현적인 속도입력에 의해 유도되는 유기기전력의 특성 식을 유도하고, 동일한 방법으로 역기전력 상수, 저항, 자기인덕턴스와 상호인덕턴스와 같은 전기적 파라미터를 얻었다. 본 논문에서 사용한 공간고조파법의 결과는 2차원 유한요소해석법 결과와 비교하여 잘 일치하는 것을 확인하였다. 이 결과는 영구자석 형 선형 발전기의 특성을 이해하는 것과 해석방법의 비교연구, 설계 최적화, 그리고 기기의 동적 모델링에 기여할 수 있다.

• 전력전자학회논문지
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• 제6권5호
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• pp.416-422
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• 2001

BLDC (Brushless DC) 전동기는 선형적인 토크 대 전류, 속도 대 전압특성을 갖고 있으며 기계적 전기적인 잡음이 없고, 가감속 제어가 용이하며, 토크 대 관성의 비가 매우 높아 소형으로 높은 출력을 낼 수 있다는 장점을 가지고 있다. 그러나 전기자 전류의 전환 (Commutation)시 고정자 권선의 인덕턴스 성분과 역기전력으로 인해 발생되는 전류리플은 BLDC 전동기의 구동시 발생되는 토크리플의 중요한 원인이 되어, 고정밀 서보계통에 대한 응용에 큰 장애가 되고 있다. 본 논문에서는 퓨리에 시리즈계수를 사용한 새로운 전류제어 알고리즘을 개발하여 상전류 전환시 발생하는 전류리플을 최소화함으로서 토크리플을 현저히 감소 시켰으며, BLDC 전동기의 구동을 위해 널리 사용되고 있는 UNIPOLAR PWM 방식과 시뮬레이션 및 실험을 통해 비교함으로써, 새로운 알고리즘의 효용성을 입증하고자 한다.