• 전기학회논문지P
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• 제57권2호
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• pp.72-78
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• 2008

The speed variation of SRM is fulfilled throughout a transition from chopping control to single pulse operation. (i,e., low speed to high speed operation). It is unsatisfied with performance at all operational regimes. In this paper, the operational performance of SRM can be improved by using current hysteresis control method. This method maintains a generally flat current waveform. At the high speed, the current chopping capability is lost due to the development of the back-EMF. Therefore SRM operates in single pulse mode. By using zero-current switching and zero-voltage switching technique, the stress of power switches can be reduce in chopping mode. When the commutation from one phase winding to another phase winding, the current can be zero as fast as possible in this period because several times negative voltage of DC-source voltage produce in phase winding. This paper is compared to performance based on conventional C-dump converter topology and the proposed resonant C-dump converter topology. Simulation and experimental results are presented to verify the effectiveness of the proposed circuit.

• Journal of Power Electronics
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• 제14권6호
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• pp.1147-1156
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• 2014

This study proposes a quasi-fixed-frequency hysteresis current tracking control strategy for modular multilevel converters (MMCs) on the basis of voltage partition principle. First, by monitoring the grid voltage and the deviation between the output and reference currents, the output voltage is determined, thus prompting the output current to quickly and efficiently track the given current. Second, the voltages of the upper/lower capacitor of the arm and the voltages between the upper and lower arms are balanced by combining these arms with virtual loop mapping and arm voltage balance control, respectively. In particular, the proposed method is designed for any level and number of sub-modules. The validity of the proposed method is verified by simulations and experimental results of a five-level MMC prototype.

• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.647-657
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• 2011

The present paper proposes a sliding mode control with fixed switching frequency for three-phase three-leg voltage source inverter based four-wire shunt active power filter. The aim is to improve phase current waveform, neutral current mitigation, and reactive power compensation in electric power distribution system. The performed sliding mode for active filter current control is formulated using elementary differential geometry. The discrete control vector is deduced from the sliding surface accessibility using the Lyapunov stability. The problem of the switching frequency is addressed by considering hysteresis comparators for the switched signals generation. Through this method, a variable hysteresis band has been established as a function of the sliding mode equivalent control and a predefined switching frequency in order to keep this band constant. The proposed control has been verified with computer simulation which showed satisfactory results.

• 전력전자학회논문지
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• 제3권4호
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• pp.382-387
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• 1998

본 논문은 신경회로망을 사용하여 PWM인버터의 스위칭주파수를 일정하게 유지시키기 위한 적응 히스테리시스 밴드 전류제어 방식을 제안하였다. 신경회로망의 지도신호로 중성점전압을 고려한 적응 히스테리시스 밴드 식을 유도하고, 이 전류제어에 적합한 신경회로망의 구조 및 학습 알고리즘을 제시하였다. 시뮬레이션을 통하여 전동기의 동작 상태에 관계없이 스위칭 주파수를 거의 일정하게 유지되며, 전류의 과도응답 특성의 우수함을 확인하였다.

• Journal of Power Electronics
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• 제18권3호
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• pp.817-825
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• 2018

In this paper, a current hysteresis control with good decoupling properties for doubly-fed brushless induction machines (BDFIMs) has been proposed based on a generalized vector model. The independent control of the reactive power and speed for BDFIMs has been achieved by controlling the d-axis and the q-axis current of the control windings (CW). The proposed vector control method has been developed for the power winding (PW) flux frame. Experimental verification of a type Y180M-4 BDFIM prototype with 1/4 pole-pairs has been presented. Evidence of its good performance has been shown through experimental results.

• 한국인터넷방송통신학회논문지
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• 제22권2호
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• pp.123-128
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• 2022

SRM(Switched Reluctance Motor)의 토크는 인덕턴스의 기울기에 비례하여 발생하기 때문에 비선형 토크 특성을 가지며 토크 맥동이 크고 소음이 심한 단점을 가지고 있다. 특히 SRM의 상용화에 가장 큰 장해 요인으로 작용하고 있는 것은 회전축에서 발생하는 맥동 토크로 이에 의해 기기자체는 물론이고 주변장치에까지 여러 가지 악영향을 미친다. 따라서 맥동 토크를 저감시키는 방법으로 다양한 방안이 국내외 연구자들에 의하여 발표되었고 히스테리시스 제어기의 경우 초핑 제어에 비해 평활한 전류를 흘려줄 수 있다는 장점이 있다는 연구결과가 있다. 그러나 히스테리시스 밴드를 결정함에 있어서 밴드가 너무 작을 경우 많은 스위칭으로 인한 스위칭 손실과 엔코더의 사용 시 불안정한 초기 기동을 야기할 수 있는 둥의 단점을 가지고 있다. 따라서 본 논문에서는 속도오차에 따른 히스테리시스 밴드의 변화를 통하여 보다 안정적이고 빠른 속도응답을 가지면서 정상상태에서 토크 리플을 줄일 수 있는 가변 히스테리시스 제어기에 대하여 연구하였다.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권3호
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• pp.397-403
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• 2012

This paper describes a control method of turn-on/off angles to improve the efficiency of the switched reluctance generator(SRG) with a power closed-loop control system, and the inner-loop of the system is current hysteresis control. The SRG control system is constituted by the PI power controller and the two-level current hysteresis controller. By measuring and analyzing the system losses of different reference powers, speeds and turn-on/off angles, selection strategy of optimal turn-on/off angles is discussed. The proposed method is simple, reliable, and easy to achieve.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.346-350
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• 1990

This paper proposes a novel current control strategy for current regulated VSI-PWM transistor inverter. The conventional hysteresis control method has good dynamic responses. But the switching frequencies are high because it does not optimize switching patterns. Proposed current control strategy can optimize switching patterns. As regulator, three level comparators are used. The outputs of the comparators select appropriate inverter output voltage vectors via switching table stored in EPROM. The simulation and exparimental results in comparison to contentional hysteresis strategy are presented and discussed.

• 조명전기설비학회논문지
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• 제21권5호
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• pp.25-31
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• 2007

본 논문에서는 스위치드 릴럭턴스 전동기 (SRM)의 히스테리시스 및 PI 전류제어기법의 응답특성에 관해 고찰하였다. SRM의 전류제어를 위해 가장 널리 적용되는 히스테리시스 제어기법은 전류응답특성이 빠르다는 장점이 있으나, 스위칭 주파수의 가변으로 인한 소음이 단점으로 알려져 있다. SRM의 전류제어를 위해 적용되는 다른 전류 제어기법으로는 PI 전류제어기법이 있으나, 비선형적인 특성으로 인해 일반적인 전동기 제어시스템과 같이 몇몇 고정된 변수들로 제어기를 설계하기가 용이하지 않다. 본 논문에서는 제한된 범위 내에서 전동기가 구동된다는 가정하에 선형화를 통한 PI 전류제어기를 설계하였다. 1마력 SRM을 적용하여 전류제어 및 속도제어 실험을 수행하였으며, 실험을 통해 얻어진 데이터는 적용 용도에 적합한 전류제어기법 선정을 위한 참고자료가 될 것으로 사료된다.

• Journal of Power Electronics
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• 제15권3호
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• pp.796-805
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• 2015

New direct and indirect current control methods for a fault-tolerant active power filter topology are presented in this paper. Since a three-phase four-switch topology has a phase bridge current which cannot be directly controlled, a hysteresis control method in the α-β plane which controls the three-phase current in the two-phase stationary coordinate system is proposed. The improved SVPWM algorithm is able to eliminate the operation of the trigonometric functions in the traditional algorithm by rotating the α-β coordinates and alternating the sequence of the output vectors, which in turn simplifies the algorithm and reduces the switching frequency. The selection of the DC-side reference voltage and DC-side capacitor equalization strategy are also discussed. Simulation and experiments demonstrate that the proposed control method is correct and feasible.