• 전기전자학회논문지
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• 제27권4호
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• pp.450-455
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• 2023

태양광 패널의 큰 기생 커패시턴스에 기인하는 과도한 누설 전류를 피하기 위한 단상 태양광 인버터 중에 부스트 컨버터와 하프브리지 인버터를 종속적으로 결합하는 방식은 가장 단순하면서 누설 전류가 가장 작다. 하지만 직류단 전압이 높아 스위칭 소자의 정격 전압이 높고 스위칭 손실이 크다. 본 논문은 부스트 컨버터를 제거하는 대신에 하프브리지 인버터의 출력 측에 2개의 양방향 스위치를 추가함으로써 벅부스트 인버터로 동작할 수 있는 새로운 회로 토폴로지를 제안한다. 고전압 직류단을 거치는 두 단계의 전력 변환을 한 단계로 줄인 덕분에 전력 손실을 절감할 수 있으며 비용 및 누설 전류는 증가하지 않는다. 제안된 회로 토폴로지의 타당성은 컴퓨터 시뮬레이션 및 전력 손실 계산을 통해 검증한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.549-551
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• 2005

Bidirectional DC/DC converters allows transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, they are being increasingly used in many applications such as battery charger/dischargers, dc uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This paper proposes a new bidirectional Sepic/zeta converter. It has low swicthing loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively. Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system . The proposed converter also has both transformerless version and transformer one.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2237-2246
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• 2017

A nonisolated two-phase bidirectional dc-dc converter (NTPBDC) is a very attractive solution for the battery energy storage system (BESS) applications due to the high voltage conversion ratio and the reduced conduction loss of the switching devices. However, a hard-switching based NTPBDC decreases the overall voltage conversion efficiency. To overcome this problem, this paper proposes a novel NTPBDC with zero-voltage-transition (NTPBDC -ZVT). The soft-switching for the boost and buck main switches is achieved by using a resonant cell, which consists of a single resonant inductor and four auxiliary switches. Furthermore, due to the single resonant inductor, the proposed NTPBDC-ZVT has the advantages of simple implementation, reduced size, and low cost. The validity of the proposed NTPBDC-ZVT is verified through experimental results.

• Journal of Power Electronics
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• 제17권2호
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• pp.334-345
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• 2017

In order to meet the increasing needs of the hybrid energy source system for electric vehicles, which demand bidirectional power flow capability with a wide-voltage-conversion range, a bidirectional three-level DC-DC converter and some control strategies for hybrid energy source electric vehicles are proposed. The proposed topology is synthesized from Buck and Boost three-level DC-DC topologies with a high voltage-gain and non-extreme duty cycles, and the bidirectional operation principle is analyzed. In addition, the inductor current ripple can be effectively reduced within the permitted duty cycle range by the coordinated control between the current fluctuation reduction and the non-extreme duty cycles. Furthermore, benefitting from duty cycle disturbance control, series-connected capacitor voltages can also be well balanced, even with the discrepant rise and fall time of power switches and the somewhat unequal capacitances of series-connected capacitors. Finally, experiment results of the bidirectional operations are given to verify the validity and feasibility of the proposed converter and control strategies. It is shown to be suitable for hybrid energy source electric vehicles.

• Journal of Power Electronics
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• 제11권1호
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• pp.1-9
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• 2011

This paper describes a two quadrant bidirectional soft switching converter for ultra capacitor interface circuits. The total efficiency of the energy storage system in terms of size and cost can be increased by a combination of batteries and ultra capacitors. The required system energy is provided by a battery, while an ultra capacitor is used at high load power pulses. The ultra capacitor voltage changes during charge and discharge modes, therefore an interface circuit is required between the ultra capacitor and the battery. This interface circuit must have good efficiency while providing bidirectional power conversion to capture energy from regenerative braking, downhill driving and the protecting ultra capacitor from immediate discharge. In this paper a fully soft switched two quadrant bidirectional soft switching converter for ultra capacitor interface circuits is introduced and the elements of the converter are reduced considerably. In this paper, zero voltage transient (ZVT) and zero current transient (ZCT) techniques are applied to increase efficiency. The proposed converter acts as a ZCT Buck to charge the ultra capacitor. On the other hand, it acts as a ZVT Boost to discharge the ultra capacitor. A laboratory prototype converter is designed and realized for hybrid vehicle applications. The experimental results presented confirm the theoretical and simulation results.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.97-105
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• 2013

The control method of the bidirectional DC/DC converter for instantaneous regenerative current control is described in this paper. The general method to control the DC/DC converter is the output voltage control. However, the regenerative current cannot be controlled to be constant with this control method. To improve the performance of the conventional control method, the DC-link voltage of the inverter is controlled within the tolerance range by the instantaneous boost and buck operations of the bidirectional DC/DC converter. By the proposed control method, the battery current can be controlled to be constant regardless of the motor speed variation. The improved performance of the DC/DC converter controlled by the proposed control method is verified by the experiment and simulation of the system with the inverter and IPMSM(Interior Permanent Magnet Synchronous Motor) which is operated by the reduced practical speed profile.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.335-336
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• 2016

This paper introduces a bidirectional full-bridge converter with new active damp structure. The proposed active damp circuit can damp the oscillating voltage across the rectifier diodes with a smaller voltage stress of the damping capacitor and eliminate the circulating current. In addition, the proposed converter can achieve additional advantages such as nearly ZCS switching for leading-leg switches and no recovery current for rectifier-bridge by the suitable design of the damp capacitor to resonate with leakage inductor. Since the ZVS is achieved for both leading-leg and lagging-leg switches by the magnetizing current of the transformer, it can be achieved regardless of the load variation. A 3.3 kW prototype converter is implemented for vehicle-to-grid (V2G) application and the advantages of the proposed converter are verified by the experiments. The maximum efficiencies of 98.2% and 97.6% have been achieved for the buck mode and boost mode operation, respectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.446-450
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• 2004

The amount of electric energy used in a vehicle will be increased continuously. The increment of electric power demand causes interest on new higher power system such as 42V Power Net. Furthermore, the necessity for development of energy storage device is highlighted recently. Bidirectional nm Converter is one of the important parts in 42V power system. Therefore, this paper proposes bidirectional Cascade Buck-Boost DC/DC Converter which can satisfies required specifications in 42V power system The operation principle is described along with simple control method, and experimental results on a 500W prototype are provided.

• Journal of Power Electronics
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• 제12권2호
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• pp.233-241
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• 2012

This paper presents a design of a 30kW 250V/530V bidirectional DC-DC converter to be used in an electrical car. A detailed explanation of the design is given. The system uses two phase shifted half bridge (boost and buck) topologies to reduce the ripple current in the output capacitor. The converter has an efficiency of 95% at nominal power. It works as a constant voltage in one direction and as a constant current in the other to charge the batteries. Simulations and measurement are done at high power to test the efficiency.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.226-239
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• 2018

In this paper, design and control method ZVT Interleaved Bidirectional LDC(IB-LDC) for mild-hybrid electric vehicle is proposed. The IB-LDC is composed of interleaved buck and boost converters employing an auxiliary inductor and auxiliary capacitors to achieve zero-voltage-transition. Operating principle of IB-LDC according to operation mode is introduced and mathematically analyzed in buck and boost mode. Moreover, PFM and phase control are proposed to reduce circulating current for low power range. Passive components design such as main inductor, auxiliary inductor and capacitors is suggested, considering ZVT condition and maximizing efficiency. Furthermore, a 600W prototype of ZVT IB-LDC for MHEVs is built and tested to verify validity.