• 조명전기설비학회논문지
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• 제27권10호
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• pp.59-68
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• 2013

This paper proposes the boost type bidirectional DC/DC converter with high efficiency for electric vehicle using an interleave method. This interleave method can reduce the system size because it reduces the ripple of output voltage and input current with no add to extra filter. Proposed system is consist of two converters and applies to interleaved method through phase shift to each converter. And it implements the high boost through voltage double and series construction of output port. Also, it reduces the price and increases the efficiency as operating the ZCS by leakage inductance of transformer and capacitor of voltage double with not add special reactor. Proposed DC/DC converter using interleave method is proved the validity through the result of PSIM simulation and experiment of 5kW DC/DC converter.

• Journal of Power Electronics
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• 제18권3호
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• pp.879-891
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• 2018

A bidirectional dc-dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc-dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc-dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.

• 전력전자학회논문지
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• 제16권6호
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• pp.618-626
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• 2011

태양전지는 미래에너지를 위한 중요한 신재생에너지원이다. 본 논문에서는 태양광 발전 (PV PCS)를 위한 2단구성 DC/DC컨버터와 동작제어를 제안한다. 넓은 입력전압 제어범위를 갖는 제안된 DC/DC컨버터는 1차 병렬 2차 직렬로 연결된 Two Tank LLC공진컨버터와 Interleaved 승압 컨버터로 구성되어있고, 태양광모듈 전압범위에 따라 하나의 시스템 또는 두 개의 시스템으로 동작시켜 전체 평균효율을 증가시키는 방법을 제안한다. 제안된 컨버터에 대한 동작특성에 대해 분석, 서술되어 있으며, 2.2kW급 시제품 제작 및 실험을 통하여 적용 가능함을 보였다.

• 전력전자학회논문지
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• 제19권5호
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• pp.431-439
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• 2014

The two-phase interleaved bidirectional DC-DC converter (TIBDC) is a very attractive solution to problems related to battery energy storage systems. However, the hard-switching TIBDC increases the switching loss and electromagnetic interference noise when the switching frequency increases. Hence, a soft-switching technique is required to overcome these disadvantages. In this study, a novel TIBDC with zero-voltage transition (TIBDC-ZVT) is proposed. Soft switching in the boost and buck main switches is achieved through a resonant cell that consists of a single resonant inductor and four auxiliary switches. Given its single resonant inductor, the proposed TIBDC-ZVT has a reduced size and can easily be implemented. The validity of the proposed TIBDC-ZVT is verified through experimental results.

• 전력전자학회논문지
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• 제19권1호
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• pp.15-22
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• 2014

Recently, parallel operation of dc-dc converters has been widely used in distributed power systems. In this paper, a control method to achieve parallel operation of three-phase bi-directional isolated interleaved dc-dc converters is discussed for the battery charging and discharging system which consists of the 32 battery charger/dischargers and two three-phase bi-directional isolated interleaved dc-dc converters. In the boost mode, the battery energy is delivered to the grid, whereas the grid energy is transferred to the battery in the buck mode operation. The average current sharing control method is employed to obtain an equal conducting of each phase current in the three-phase dc-dc converter. By using the proposed method, the imbalance factor is gratefully reduced from 8 percent to 1 percent. Two 2.5kW three-phase bi-directional dc-dc converter prototype have been built and the proposed method has been verified through experiments.

• Journal of Power Electronics
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• 제10권2호
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• pp.132-137
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• 2010

Interleaving techniques are widely used to reduce input/output ripples and to increase the power capacity of boost converters operating in critical conduction mode. Two types of phase-shift control schemes are studied in this paper, the turn-on time shifting method and the turn-off time shifting method. It is found that although the turn-off time shifting method exhibits better performance, it suffers from sub-harmonic oscillations at high input voltages. To solve this problem, an intensive quantitative analysis of the sub-harmonic oscillation phenomenon is made in this paper. Based upon that, a novel modified turn off time shifting control scheme for interleaved boost converters operating in critical conduction mode is proposed. An important advantage of this scheme is that both the master phase and the slave phase can operate stably in critical conduction mode without any oscillations in the full input voltage range. This method is implemented with a FPGA based digital PWM control platform, and tests were carried out on a two-phase interleaved boost PFC converter prototype. Experimental results demonstrated the feasibility and performance of the proposed phase-shift control scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.961_962
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• 2009

A novel, two-inductor, interleaved power-factor-corrected (PFC) boost converter that exhibits voltage-doubler characteristic when it operates with a duty cycle greater than 0.5 is introduced. The voltage-doubler characteristic of the proposed converter makes it quite suitable for universal-line (90~265VRMS) PFC applications. Because the proposed PFC boost rectifier operates as a voltage doubler at low line, its low-line range efficiency is greatly improved compared to that of its conventional counterpart. The performance of the proposed PFC rectifier was evaluated on an experimental 300W PFC prototype.

• 전력전자학회논문지
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• 제22권4호
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

• 전력전자학회논문지
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• 제20권3호
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• pp.214-222
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• 2015

The superiority of gallium nitride FET (GaN FET) over silicon MOSFET is examined in this paper. One of the outstanding features of GaN FET is low reverse-recovery charge, which enables continuous conduction mode operation of totem-pole bridgeless boost power factor correction (PFC) circuit. Among many bridgeless topologies, totem-pole bridgeless shows high efficiency and low conducted electromagnetic interference performance, with low cost and simple control scheme. The operation principle, control scheme, and circuit implementation of the proposed topology are provided. The converter is driven in two-module interleaved topology to operate at a power level of 5.5 kW, whereas phase-shedding control is adopted for light load efficiency improvement. Negative bias circuit is used in gate drivers to avoid the shoot-through induced by high speed switching. The superiority of GaN FET is verified by constructing a 5.5 kW prototype of two-module interleaved totem-pole bridgeless boost PFC converter. The experiment results show the highest efficiency of 98.7% at 1.6 kW load and an efficiency of 97.7% at the rated load.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.149-150
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• 2013

비반전 승강압형 토폴로지인 Cascaded Buck-Boost는 크게 Buck단과 Boost단으로 나눌 수 있다. 2상 병렬로 연결되는 Cascaded Buck-Boost 컨버터는 병렬로 연결되는 소자에 따라서 총 3가지의 회로 구성이 가능하며, 제어방법에 따라 1개의 스위치로도 Interleaved 회로처럼 동작이 가능하다. 본 논문에서는 각각의 Cascade Buck-Boost 컨버터의 병렬 구성에 따른 입출력 전압비, 전류리플, 시스템 효율 등을 분석한다.