• 대한전기학회논문지
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• 제38권10호
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• pp.832-839
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• 1989

New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit with minimum number of swithcing elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are analyzed in the steady state. The details of operation of the chopper circuits are also fully described and experimented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.223-226
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• 2003

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.

• 대한전기학회논문지
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• 제34권3호
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• pp.115-123
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• 1985

A two phase chopper system with two separate groups of DC motors for regenerative braking is dealt with in this article. The main circuit consists of two sets of chopping parts, four diodes and two separate groups of DC motors. Although the proposed chopper circuit requires more circuit elements than the conventional two phase chopper system with combined output, it has the following advantages`(1). Ripple frequency of smoothing reactor current becomes twice as high as that of the conventional system, so the continuous current range and the ripple ratio are improved greatly. Therefore, the efficiency becomes even higher, the capacity of commutation equipment is reduced and the inductive interference become less.(2). Load current division becomes equalized. Therefore it is possible to drive not only series motors but also shunt, separately excited and compound motors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.164-165
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• 2012

This paper proposes an AC Chopper based DC power supply for specific DC voltage ranges. AC chopper is attached to the input side of PFC to generate specific ranges of DC voltage which are not available with PFC itself alone. The input power factor of the proposed DC power supply is proportional to that of PFC. Performance of the proposed power supply was verified by carrying out simulations.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.576-588
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• 2014

The superiority of CMI (Cascaded Multilevel Inverter) is unparalleled in high power and high voltage STATCOM (Static Synchronous Compensator). However, the parameters and operating conditions of each individual power unit composing the cascaded STATCOM differ from unit to unit, causing unit voltage disequilibrium on the DC side. This phenomenon seriously impairs the operation performance of STATCOM, and thus maintaining the DC voltage balance and stability becomes critical for cascaded STATCOM. This paper analyzes the case of voltage disequilibrium, combines the operation characteristics of the cascaded STATCOM, and proposes a new DC voltage control scheme with the advantages of good control performance and stability. This hierarchical control method uses software to achieve the total active power control and also uses chopper controllers to enable that the imbalance power can flow among the capacitors in order to keep DC capacitor voltages balance. The operating principle of the chopper controllers is analyzed and the implementation is presented. The major advantages of the proposed control strategy are that the number of PI regulators has been decreased remarkably and accordingly the blindness of system design and debugging also reduces obviously. The simulation reveals that the proposed control scheme can achieve the satisfactory control goals.

• 전기학회논문지
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• 제61권12호
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• pp.1848-1856
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• 2012

This paper proposes a new grid-tied power conditioning system for battery energy storage, which is composed of a 2-stage DC-DC converter and a PWM inverter. The 2-stage DC-DC converter is composed of an LLC resonant converter connected in cascade with a 2-quadrant hybrid-switching chopper. The LLC resonant converter operates in constant duty ratio, while the 2-quadrant hybrid-switching chopper operates in variable duty ratio for voltage regulation. The operation of proposed system was verified through theoretical analysis and computer simulations. Based on computer simulations, a hardware prototype was built and tested to confirm the technical feasibility of proposed system. The proposed system could have relatively higher efficiency and smaller size than the existing system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.509-514
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• 2004

This paper introduces the modified slip energy recovery system in order to improve its power factor and to reduce harmonics of line current waveforms. Twelve pulse line commutated converter with the chopper type IGBT is applied where the chopper is applied across the DC terminal and the chopped DC is fed to the converter operating as an inverter and then passed through the wye-wye and delta-wye transformer circuit. This scheme leads to be able to adjust the speed of the motor by the duty cycle of the chopper operating in PWM mode. The fuzzy logic controller is also introduced to the modified slip energy recovery system for keeping the motor speed to be constant when the load varies. The experimental results in testing the 0.22 kW wound rotor induction motor from no-load condition to rated condition show the effectiveness of the proposed control scheme.

• 전기학회논문지P
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• 제63권4호
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• pp.361-367
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• 2014

This paper is related to a new solar power conditioner for a built-in step-up chopper function. In the first step-up chopper proposed solar PV power conditioner for mutually connected in series with the input voltage of the bypass diodes are respectively connected to the positive terminal should install the mutual boosting chopper diode connected in series with the boost chopper switching element between the two power supply and at the same time the first and the second was connected to a second diode and a resonance inductor and a snubber capacitor in series with each other. And the common connection point between the bypass diode and the step-up chopper and the step-up chopper diode common connection point of the switching elements of the input voltage was set to the boost inductor for storing energy. In addition, between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point of the first auxiliary diode and the second common connection point of the auxiliary diode was provided, the resonance capacitor. Between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point and the common connection point of the resonance inductor snubber capacitor and connecting the third secondary diode, between two power supply lines is characterized by configuring the DC link capacitor bus lines in parallel. Therefore, it is possible to suppress the switching loss through, DC link bus lines, as well as there could seek miniaturization and weight reduction of the power conditioner itself by using a common capacitor of the non-polar non-polar electrolytic capacitor having a capacitor, the service life of the circuit can be extended and it is possible to greatly reduce the loss can be greatly improve the reliability of the product and the operation of the product itself.

• 전력전자학회논문지
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• 제3권4호
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• pp.323-329
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• 1998

계통연계형 태양광발전시스템을 PWM 쵸퍼와 전류형 인버터로 구성하였다. 전류형 인버터의 직류리액터를 경감하는 방법으로, 직류측에 병렬공진회로를 삽입함에 따라 맥동전력의 일부를 교류 전해콘덴서에 축적하여 직류전류의 맥동을 억제하는 방법과, 쵸퍼의 변조파를 전원주파수의 2배로 제어하여 직류전류의 맥동을 억제하는 것을 비교 검토하였다. 그리고 태양전지전류와 쵸퍼의 변조율만을 이용하여 태양전지가 항상 최대출력점에서 동작하도록 하였다. 계통과 연계함으로서 출력전력이 부하전력보다 큰 경우에는 잉영전력을 계통전원에 공급하고, 발전전력 부하전력에 대해 부족한 경우에는 계통전원이 부족분을 공급하는 것을 확인하였다.

• 조명전기설비학회논문지
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• 제23권9호
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• pp.98-107
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• 2009

기존의 하드 스위칭 고주파 PWM DC-DC 컨버터는 펄스 변조 캐리어 주파수의 고주파화를 수반하고, 전력용 반도체 스위칭 소자의 스위칭 손실의 증대나 스위칭 과도현상이 수반된 전압 서지나 전류 서지에 의한 EMI 등의 문제점들이 있다. 이러한 문제를 효과적으로 해결하기 위해 본 논문에서는 새로운 소용량 승압형 PWM 쵸퍼 회로의 동작원리를 서술하고, 시뮬레이션과 실험을 통하여 특성을 도출하였다.