• 대한전기학회논문지
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• 제33권8호
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• pp.316-324
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• 1984

In the wound rotor induction motor, the external resistor is usually added to the rotor circuit in order to limit the starting current. In this scheme, whilst the starting current is limited, the available torque is remarkably reduced. In this paper, to improve the starting characteristics the stator current can be maintained constant by adjusting the external resistor. To change the external resistor, teh chopper and the resistor is connected in parallel, and the chopper duty cycle is adjusted by microprocessor. The duty cycle is calculated according to the actual speed of motor by microprocessor look-up table map. In this suggested scheme, the starting characteristics are remarkably improved without over-current. The starting time of this system is reduced by 20-48 Percent compared with fixed extemal resistance system in the same load.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.137-142
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• 1998

This paper describes a simple vector control scheme for the wound rotor type induction motors(WRIM) without the additional speed sensor in order to remove the external resistor bank which is usually adapted for the WRIM speed control. The motor angular speed is obtained indirectly from the slip angular speed is obtained indirectly from the slip angular speed and the slip angular speed is estimated by detecting the rotor currents only. Because the motor parameters are not included in the estimation algorithm, the proposed algorithm is free from the variation of the motor parameters and the robust sensorless vector control can be achieved. The performance of the proposed scheme is verified through the digital simulation.

• 한국철도학회논문집
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• 제4권1호
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• pp.16-22
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• 2001

This paper describes two different systems which can compensate harmonic currents generated in the power system. As non-linear loads increase gradually in industry fields, harmonic current generated in the electric power network system also increases. Harmonic current makes a power network current distorted and generates heat, vibration, noise in the power machinery. Many approaches have been applied to compensate harmonic currents generated in the power network system. Among various approaches, in this paper, two kinds of approaches are compared and evaluated. They are flywheel compensator based on secondary excitation of wounded rotor induction motor(WRIM) and primary excitation of squirrel cage induction motor(SCIM). Both systems have a common structure. They use a flywheel as a energy storage device and use PWM inverters.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권12호
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• pp.704-713
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• 2002

This paper describes operational characteristics of wind turbine induction generators interconnected with distribution networks using PSCAD/EMTDC. Due to the simple and durable structure, induction generators are the most common type used in wind Power generation. Generally, induction generators are classified into two groups according to the shape of rotor, one is squirrel-cage type and the other is wound-rotor type. In this study, we simulate the start-up and the output variation of generators interconnected with distribution networks and compare the operational characteristics of squirrel -cage type and wound-rotor type induction generators located in the unfaulted distribution lines about the disturbance occurred on the associated distribution feeders emanated from the substation to which wind turbine generator is connected. In order to obtain the realistic results, we use the radial distribution network of IEEE 13-bus model.

• 조명전기설비학회논문지
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• 제13권4호
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• pp.27-31
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• 1999

본 연구는 산업분야의 수많은 전기설비 시스템에 널리 사용되고 있으며 또 이중여자기로도 사용될 수 있는 권선형 유도전동기의 기동특성과 설계를 다루었다. 고정자는 재래색 3상 권선형 유도 전동기의 고정자와 동일하고 회전자 권선은 새로운 방법으로 재권선한 결과 기동토크로 크고 기동전류는 작으며 운전효율은 좋아졌다. 뿐만 아니라 슬립링과 브러쉬 및 외부저항의 필요성이 없어 구조가 간단하고 시스템 비용을 절약할 수 있을 뿐 아니라 유지보수비도 절약할 수 있었다.

• 대한전기학회논문지
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• 제37권1호
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• pp.33-39
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• 1988

In this paper, a stand-alone wound rotor induction generator system is proposed and its steady state characteristics are analyzed. It is shown that the self-excitation of the system can be acheined by exciting the rotor through the PWM inverter. The analysis is based upon the eguivalent circuit and the steady state dq model of the mahine. The results show that the proposed system can be made to generate constant voltage constant frequency power for various speed and load conditions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.750-753
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• 2005

This paper presents a method of detecting rotor position for single phase Switched Reluctance Motors(SRMs) using searchs coil. In the single phase SRM, mainly Hall effect sensors or photo interrupters have been used to detect the rotor position. But these sensors cause high cost and increase the volume of the motor, Furthermore when the motor is used in very hostile environment like high temperature or pressure, its reliability goes down. In this paper, low cost and robust characteristics of rotor position detection method are focused in order to compensate for disadvantage of existing sensors. Search coils wound around the stator pole are used for detection of the rotor position in single phase SRM. Rotor position detection is achieved through electromotive force patterns induced by time-varying flux linkage in the search coil. The validity of the method is verified by experimental results.

• 전력전자학회논문지
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• 제6권1호
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• pp.57-63
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• 2001

산업 현장에서 널리 사용되고 있는 권선형 유도전동기 제어 시스템은 외부 2차 저항과 각종 접점으로 인해 효율과 유지 $.$ 보수상의 문제점을 안고 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 기촌의 전동기 시스템에 별도의 장치를 부과하지 않고 2차 전류만을 검출하여 간단히 권선형 유도전동기를 제어할 수 있는 센서리스 벡터 제어 기법을 제안했다. 즉, 권선형 유도전동기활 제어하기 위해 필요한 기존의 외부 2차 서항이나 잔자접촉기들을 제거하고 회전자측을 완전히 단락시켜 2차 저항에 의한 전략손실이나 접점의 마모로 인한 유지.보수상의 문제점 을 제거했다. 또한. 제안된 센서리스 벡터제어 알고리즘은 기존의 얄고리즘과는 단리 여자 전류 및 슬립주파수 측 정에 전동기 2차 저항을 사용하지 않기 때문에 2차 저항 변동으로 인한 벡터제어의 불완전함을 제거했다. 아울러 디지털 시뮬레이션과 실험을 통해 제안된 알고리즘의 타당성을 확인을 하였다.

• 전기의세계
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• 제24권2호
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• pp.78-83
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• 1975

There are many studies recently, on a wound rotor induction motor operation as synchronous rotating speed, and such an induction motor is so called an induction synchronous motor. In above desciption the region of pull into-step that the wound rotor induction motor as a synchronous motor has not been calculated. This paper deals with such a region. Generally, induction synchronous motor is different from a synchronous motor in many respects. In considering these respects, characteristic equations of motion for this motor are induced adoption small signal linearization, continuous quasili-nearization and state variable grouping technique. For pulling-into-step of Induction Synchronous Motor, we first analyze these equations with digital computer and compare the former with datas calculated by motor experimentation.

• 전기학회논문지
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• 제62권1호
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• pp.37-42
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• 2013

This paper deals with Wound Rotor Synchronous Motor (WRSM) purposely designed for Integrated Starter and Generator (ISG) installed in 42V automotive electrical system. Not only design objective and specifications of WRSM, but its adaptive design to minimize torque ripple and back-EMF Total Harmonics Distortion (THD) are considered. Furthermore, design characteristics of designed prototype have been investigated numerically in terms of torque, back EMF, loss, and efficiency, which are verified by performance comparison with Interior Permanent Magnet Synchronous Machine based on Finite Element Analysis (FEA).