• 전력전자학회논문지
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• 제3권1호
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• pp.46-52
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• 1998

본 논문은 스위치드 릴럭턴스 전동기의 자기포화 비선형 상태를 고려하여 일정 토오크 발생을 위한 전류형태 구현에 관한 방법을 기술한다. 본 연구에서는 인덕턴스 증가영역에서의 전류 검출방법 및 비선형 인덕턴스 프로파일 모델링을 위한 근사화 기법이 채택되었다. 그리고 제안된 시스템에서 부하조건에 관계없이 일정토오크 발생을 위한 전류파형을 생성하기 위하여 단일스위칭 각도 제어 및 전압제어 방법이 사용되었다. 마지막으로 3HP 6/4 스위치드 릴럭턴스 전동기를 사용하여 본 연구의 타당성을 실험적으로 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.21-24
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• 2002

The vector control system of an induction motor is the high performance drive system to achieve the instantaneous torque control. The vector control system is greatly divided into the direct control, and the indirect control that the most widely is used, The indirect vector control needs the rotor time constant, which changes widely according to the temperature, frequency, and current amplitude. The incorrect time constant leads to the saturation of magnetic flux or under-excitation phenomena. As a result, that deteriorate the control performance. Therefore, in this paper, the effect of time constant variation is investigated and its on-line tuning algorithm is proposed. The time constant using the torque angles was calculated and that of the validity of algorithm proposed was proved through the computer simulation and the experiment.

• 전력전자학회논문지
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• 제14권4호
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• pp.268-277
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• 2009

본 논문은 DTC-PWM을 적용한 PMSM의 속도제어 방식을 제안한다. 제안된 DTC-PWM은 기존의 DTC 방식과 PWM을 결합한 방식으로 스위칭 신호를 발생하는 구조를 가진다. 제안된 방식에서 실제 토크는 기존의 DTC 방식과 같이 추종되지만, 스위칭 신호는 토크 오차와 제어규칙에 따라 PWM 방식으로 제어한다. 토크와 자속을 제어하기 위한 스위칭 신호는 하나의 유효전압벡터와 영전압벡터로 구성되는 비대칭 스위칭 방식이 적용된다. 제안된 방식은 SVPWM과 같이 복잡한 계산없이 간단한 PWM의 연산으로 제어기를 구성하여 토크와 자속을 연속적으로 제어할 수 있다. 제안된 방식은 PMSM의 속도 제어 실험을 통하여 그 성능을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권1호
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• pp.9-15
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• 2006

The conventional hysterysis band DTC(Direct Torque Control) strategy have relatively high torque ripple at low speed and variable switching frequency according to motor speed even though it provides a fast torque response with very simple scheme consisted with only two hysteresis band comparators and a switching table for torque and flux control. In this paper, author proposed a new DTC scheme based on the torque slope and reference voltage control. The new scheme can maintain the minimized torque ripple and constant switching frequency. Experimental tests carried out with an 1.5kW induction motor drive system show improved dynamic characteristics and prove the feasibility of proposed strategy.

• 전기학회논문지P
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• 제52권1호
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• pp.1-8
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• 2003

The paper proposes instantaneous torque control of IPMSM for maximum torque drive of torque and current plane. The control scheme is based on the mathematical model of the motor and is applicable to the constant torque and field weakening operations. The scheme allows the motor to be driven with maximum torque per ampere(MTPA) characteristic below base speed and it maintains the maximum voltage limit of the motor wide field weakening and the motor current limit under all conditions of operation accurately. For each control mode, a condition that determines the optimal d-axis current $^id$ for maximum torque operation is derived. The proposed control algorithm is applied to IPMSM drive system for drive of wide speed range, the operating characteristics controlled that maximum torque control are examined in detail by simulation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권1호
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• pp.23-29
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• 2001

A BLDC motor has a serious drawback that torque pulsation is generated in every commutation period though it has many advatages compared to the conventional DC Motor. In this paper, the influence of commutation time on torque pulsation is studied. Generally in calculating the torque of BLDC motor, it is assumed that the decaying phase back EMF is constant, but the torque model considering decaying phase back EMF is introduced here. Through it, the torque in commutation period has torque pulsation component caused by commutation itself and it cannot be removed perfectly even if there is no current pulsation. To reduce the torque pulsation, a new method is proposed, which controls a point of commutation and the optimal point of commutation is found. Simulation shows that proposed method reduces the torque pulsation considerately.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.148-150
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• 2007

A novel torque sharing function (TSF) is presented. To improve efficiency and to reduce torque ripple in commutation region, only a phase torque under commutation is regulated to produce a uniform torque. And the torque developed by the other phase remains with the previous state under a current limit of the motor and drive. If the minimum change of a phase torque reference can not satisfy the total reference torque, two-phase changing mode is used. Since a phase torque is constant and the other phase torque is changed at each rotor position, total torque error can be reduced within a phase torque error limit. And the total torque error is dependent on the change of phase torque. To consider non-linear torque characteristics and to suppress a tail current at the end of commutation region, the incoming phase current is changed to torque increasing direction, but the outgoing phase current is changed to torque decreasing direction. So, the torque sharing of the outgoing phase and incoming phase can be smoothly changed with a minimum current cross over. The proposed control scheme is verified by some computer simulations and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.138-140
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• 2007

A novel non-linear logical torque sharing function (TSF) is presented. To improve efficiency and to reduce torque ripple in commutation region, only a phase torque under commutation is regulated to produce a uniform torque. And the torque developed by the other phase remains with the previous state under a current limit of the motor and drive. If the minimum change of a phase torque reference can not satisfy the total reference torque, two-phase changing mode is used. Since a phase torque is constant and the other phase torque is changed at each rotor position, total torque error can be reduced within a phase torque error limit. And the total torque error is dependent on the change of phase torque. To consider non-linear torque characteristics and to suppress a tail current at the end of commutation region, the incoming phase current is changed to torque increasing direction, but the outgoing phase current is changed to torque decreasing direction. So, the torque sharing of the outgoing phase and incoming phase can be smoothly changed with a minimum current cross over. The proposed control scheme is verified by some computer simulations and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.298-302
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• 1994

Brushless DC motors have a trapezoidal back EMF wave form and are fed with rectangular stator currents. Under these conditions, the torque produced is theoretcally constant. However, in practice, torque ripple may exist, one major cause of which conies from phase current commutation. In this paper we propose an improved method of reducing the torque ripple due to phase current commutation of indirectly restricting the uncommutated current through control of the other phase currents. Simulation results are present.

• 전력전자학회논문지
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• 제4권2호
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• pp.201-208
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• 1999

본 논문에서 회전자 시정수 변화에 따른 벡터제어 시스템의 성능저하에 대하여 고찰하고, 동기좌표계의 탄젠트 토크각과 정지좌표계의 탄젠트 토크각의 일치 관계를 이용하여 온라인으로 회전자 시정수의 변화를 추정하는 알고리즘을 제안한다. 제안한 알고리즘의 타당성을 검토하기 위하여 컴퓨터 시뮬레이션 및 실험을 수행하였다.