• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.235-240
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• 2007

A large power fuel cell generation system needs a parallel operation of de-de boost converter. Therefore, this paper proposed parallel operation algorithms of de-de boost converters for the large scale fuel cell generation system of 250[kW] and the operating principle along with the control method in detail. This paper uses a maximum current sharing method as a parallel operation method and also the phase shift full bridge de-de converter as a de-de boost converter. Simulation and experimental results on two prototype converter modules of 500W show that the parallel operation method can be applied to the 250[kW] power converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.430-433
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• 2003

IGBTS are widely used for the industrial inverters in the mid power range at low voltage (440V$\~$660V) application. Advantageous features of the device are simple gate drive and high speed switching capability. Due to these advantages the application of IGBTS is enlarging into the high power application. However, to increase the power handling capacity at lower input voltage level, the current rating in each bridge arm must be enlarged. Therefore the parallel operation of IGBT devices is essentially needed. This paper describes the feasible parallel structures of the power circuit for the mid & the high power inverters and introduces the important design condition for the parallel operation of IGBT devices. To verify feasibility of the IGBT parallel operation, the feature of several IGBT devices (EUPEC, SEMIKRON's IGBT) are investigated and the power stacks are implemented and tested with these devices. The experimental results show the good characteristics for the parallel operation of IGBTS.

• 전기학회논문지
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• 제58권1호
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• pp.86-92
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• 2009

This paper presents development of 6kw ZVS(Zero Voltage Switching) boost converter by 4-parallel operation. To realize a high capacity converter with 6 kw, 4-parallel operation of 1.5kW unit module is proposed in this paper. To meet high ratio input to output voltage, isolated type booster converter is designed. To achieve ZVS operation of 4-switches of full bridge and protect a voltage overshoot caused by switch turn-off, simple active-clamp circuit is applied to the primary side. For parallel operation of 4-modules, master-slave control method is proposed to achieve input current sharing of 4-unit converter modules accurately. For performance tests, simulation is carried out. Also, load and experimental tests of the developed booster converter, 230Vdc/6kW, are carried out under various conditions. For field tests, the developed converter is applied for boosting a battery power to high DC_link voltage for a VSI inverter which starts a micro-turbine(MT) installed in vehicle and it's performance is verified through high speed motoring a MT up to tens of thousands of rpm.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권4호
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• pp.477-483
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• 2015

The k-Winners-Take-All (kWTA) is an operation to find the largest k (>1) inputs among N inputs. Parallel search algorithm of kWTA for digital inputs is not invented yet, so most of digital kWTA architectures have O(N) time complexity. A parallel search algorithm for digital kWTA operation and the circuits for its VLSI implementation are presented in this paper. The proposed kWTA architecture can compare all inputs simultaneously in parallel. The time complexity of the new architecture is O(logN), so that it is scalable to a large number of digital data. The high-speed kWTA operation and its O(logN) dependency of the new architecture are verified by simulations. It takes 290 ns in searching for 5 winners among 1024 of 32 bit data, which is more than thousands of times faster than existing digital kWTA circuits, as well as existing analog kWTA circuits.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.390-393
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• 2007

The reliability as well as the power capability of the UPS system can be increased by replacing a single UPS unit with multiple small UPS units in parallel, resulting in a so-called module UPS. This module UPS system allows that a new module can be added or replaced while maintaining power to loads, which is a hot-swappable operation. In addition, it has desirable features such as ease of output power expandability, convenience of maintenance and repair, and high reliability. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. 5kVA modules are designed and implemented to confirm the effectiveness of the proposed approaches. Experimental results show that the module UPS system has a high power factor, a low distortion of output voltage and input current, hot-swappable operations and good load sharing characteristics.

• 전력전자학회논문지
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• 제10권5호
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• pp.443-449
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• 2005

본 논문에서는 연료 전지 시스템을 위한 Z-소스 인버터로 구성된 병렬 운전 시스템을 제시 하였다. PWM 방식으로는 Carrier phase shifted SPWM을 적용하였으며 이 방식은 출력 전류의 고조파 성분을 줄일 수 있는 장점을 갖는다. 그러나 이 기법을 Z-소스 인버터로 구성된 병렬 운전 시스템에 적용하는 경우 추가적으로 순환 전류를 발생한다. Z-소스 인버터로 구성된 병렬 운전 시스템이 동작 시 발생하는 순환 전류를 분석하고 순환 전류를 감소시키며, 부하전류에 낮은 고조파 성분을 가질 수 있도록 순환 전류 리액터를 사용하였다. 이에 대한 적합성을 시뮬레이션과 실험을 통해 입증하였다.

• 전력전자학회논문지
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• 제7권5호
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• pp.499-508
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• 2002

본 논문에서는 N.1 모듈형 UPS 시스템의 병렬운전을 위해 기존에 사용된 부하분담용 신호선을 제거하고 독립적인 운전을 수행하는 새로운 형태의 wirelss 병렬제어 알고리즘을 제안하고자 한다. 제안된 제어시스템은 기존 방식이 갖는 센싱 노이즈나 상호간섭에 의한 문제를 제거할 수 있다. 또한 wireless방식의 단점을 보완하기 위해 인버터간 불평형요소 제거 알고리즘을 적용하여 무효전력편차의 발생을 최소화하는 구조를 가지며, 시스템의 불안정한과도특성을 완충하는 가상의 임피던스를 삽입하여 과도순환전류를 저감하는 방식이 적용되었다. 제안된 알고리즘의 타당성을 검증하기 위해 시뮬레이션 결과를 제시하였다.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.408-421
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• 2008

In this paper, the parallel operation for a FC generation system is introduced and designed in order to increase the capacity for the distributed generation of a proton exchange membrane fuel cell (PEMFC) system. The equipment is the type that is used by parallel operated PEMFC generation systems which have two PEMFC systems, two dc/dc boost converters with shared dc link, and a grid-connected dc/ac inverter for embedded generation. The system requirement for the purpose of parallel operated generation using PEMFC system is also described. Aspects related to the mechanical (MBOP) and electrical (EBOP) component, size, and system complexity of the distributed generation system, it is explained in order to design an optimal distributed generation system using PEMFC. The optimal controller design for the parallel operation of the converter is suggested and informative simulations and experimental results are provided.

• 전력전자학회논문지
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• 제21권6호
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• pp.473-480
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• 2016

This study proposes a performance improvement for parallel-connected thyristor dual converters using a circulating current with an unbalanced parallel operation compensator. The proposed control method determines a variable reference value for the voltage PI controller according to voltage error at firing angle control applied to a difference current control. This method uses circulating current control to maintain a stable voltage and excellent current response during parallel operation. The effectiveness of the proposed control is verified with a simulation and an experiment based on the comparison of the performance of the proposed control method with other conventional methods.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1097-1108
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• 2023

Recently, demand for technology for energy economy and stable supply is increasing due to the increase in power demand of loads. The amount of DC power generation using new and renewable energy is noticeably increasing, and the use of DC power supplies is also increasing due to the increase in electric vehicles and digital loads. During parallel operation to increase the capacity of the power converter, the module bus method or the method using Can communication and serial communication has significant difficulties in smooth operation due to communication time delay for information sharing. Synchronization of information sharing of each power converter is essential for smooth parallel operation, and minimization of communication time delay is urgently needed as a way to overcome this problem. In this paper, a new communication method using pulse width information is proposed as a communication method specialized for parallel operation of power converters to compensate for the disadvantage of communication transmission delay in the existing system. The proposed communication method has the advantage of being easily implemented using the PWM and Capture function of the microcomputer. In addition, the DC/DC converter for DC distribution was verified through simulation and experiment, and it has the advantage of easy capacity expansion when applied to parallel operation of various types of power converters as well as DC/DC converters.