• 전기학회논문지P
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• 제54권4호
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• pp.171-178
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• 2005

The proposed dual-output DC-DC converter that bases on flyback converter can obtain two output voltage with non-isolated main-output and isolated sub-output at the same time using single-winding high frequency transformer. It can solve problems in multi-winding converter that use one main-switch, and also control quality of isolated sub-output voltage can be improved by additional sub-switch to the second. For analysis and design of the proposed converter system, converters are classified as operation mode from switching state and are become modeling by applying state space averaging method. Steady-state characteristics and dynamic characteristics are analyzed by DC component and perturbation component from state space averaging model. From experiment converter, validity of analysis and design for the propose converter system is confirm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.229-230
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• 2015

This paper presents practical details about control-loop design and dynamic analysis for a voltage-mode controlled isolated double step-down DC-DC converter. Graphical loop gain method is used to design the feedback compensation and analyze the closed-loop performance of isolated double step-down DC-DC converter. The results of the control design and closed-loop analysis are validated by experiments on a prototype converter.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권8호
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• pp.423-429
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• 2006

Recently, the high frequency isolated boost DC/DC converter has been widely used for the PCS (Power Conditioning System) system because of its small size and low cost. However, the high frequency isolated boost DC/DC converters applied the conventional voltage-fed converter and current-fed converter have the problems such as the high conduction losses and the surge voltage due to the high circulating current and the leakage inductance, respectively. To overcome this problems, in this paper the secondary LLC resonant converter is proposed, and the experimental results of the secondary LLC series resonant converter for boost DC/DC converter are verified on the simulation based on the theoretical analysis and the 700W experimental prototype.

• 전기학회논문지
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• 제66권9호
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• pp.1341-1350
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• 2017

In this paper, a high reliability 30W DC-DC converter is designed considering military standard (MIL-STD) for military applications such as guided weapon and aircraft. The performances and specifications of conventional military grade DC-DC converter are practically analyzed. The requirements for military grade DC-DC converter are established in consideration of MIL-STD and analysis results of conventional product. Two isolated DC-DC converter, forward and fly-back converter, are designed and compared to determine topology. From experimental results under various operating conditions, the forward topology satisfied performances and specifications of MIL-STD for military DC-DC converter.

• 한국정보전자통신기술학회논문지
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• 제12권1호
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• pp.99-105
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• 2019

전기 자동차의 배터리 충전용 OBC는 주로 PFC회로와 절연형 DC-DC 컨버터 회로를 포함한 2단으로 구성된다. 일반적으로 PFC 회로로는 구조가 간단한 비절연형 부스트 컨버터가 사용되고, 절연형 DC-DC 컨버터로는 ZVS(Zero Voltage Switching)가 가능한 공진형 컨버터가 이용되고 있다. 전기자동차의 주행거리 증가에 따른 넓은 배터리 출력에 대응하기 위해서는 OBC의 넓은 출력범위가 필요하지만, 이러한 시스템 회로 구성에서는 ZVS를 위한 회로설계의 한계와 제어기 구성이 복잡해지기 때문에 배터리 충전에 요구되는 넓은 범위의 출력에 효과적으로 대응하기에는 어려움이 있다. 본 논문에서는 절연형 전류원 방식의 PFC 회로와 벅 DC-DC 컨버터로 구성된 OBC를 제안하였다. 제안된 OBC는 회로 및 제어기 구성이 용이하고, 넓은 출력범위에 대한 대응이 가능하다. 제안된 회로의 유효성을 검증하기 위해 3.3㎾급 시작품을 제작 하였으며, 동작결과 출력전압 150V~400V에서 동작안정성 및 정격 부하 조건에서 최대 효율 94.4%, 최대 역률 99.2%를 확인하였다.

• Journal of Power Electronics
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• 제18권3호
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• pp.651-661
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• 2018

This paper suggests a new non-isolated high voltage gain DC-DC converter with two switches. The proposed two-switch converter has the following characteristics: a high voltage gain, a continuous input current with a small ripple, a reduction in the size of the inductor, and a simple circuit with only a few elements. A theoretical analysis, guidelines for parameter selection, and a comparison with conventional non-isolated high step-up converters are presented. A prototype of 250 W is set up to demonstrate the correctness of the proposed converter. Results obtained from simulations and experiments are presented.

• Journal of Power Electronics
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• 제13권5호
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• pp.766-778
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• 2013

The depletion of natural resources and renewable energy sources, such as photovoltaic (PV) energy, has been highlighted for global energy solution. The PV power control unit in the PV power-generation technology requires a high step-up DC-DC converter. The conventional step-up DC-DC converter has low efficiency and limited step-up ratio. To overcome these problems, a novel high step-up DC-DC converter using an isolated switched capacitor cell is proposed. The step-up converter uses the proposed transformer and employs the switched-capacitor cell to enable integration with the boost inductor. The output of the boost converter and isolated switched-capacitor cell are connected in series to obtain high step-up with low turn-on ratio. A hardware prototype with 30 V to 40 V input voltage and 340 V output voltage is implemented to verify the performance of the proposed converter. As an extended version, another novel high step-up isolated switched-capacitor single-ended DC-DC converter integrated with a tapped-inductor (TI) boost converter is proposed. The TI boost converter and isolated-switched-capacitor outputs are connected in series to achieve high step-up. All magnetic components are integrated in a single magnetic core to lower costs. A prototype hardware with 20 V to 40 V input voltage, 340 V output voltage, and 100 W output power is implemented to verify the performance of the proposed converter.

• 전력전자학회논문지
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• 제22권2호
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• pp.109-117
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• 2017

This paper describes the design and implementation of a unit module for a 10 kVA class 13.2 kV/220 V unidirectional solid-state transformer (SST) with silicon-carbide metal-oxide-semiconductor field-effect transistors. The proposed module consists of an active-front-end (AFE) converter to interface 1320 V AC voltage source to 2500 V DC link and an isolated resonant DC-DC converter for 500 V low-voltage DC output. The design approaches of the AFE and the isolated resonant DC-DC converters are addressed. The control structures of the converters are described as well. The experiments for the converters are performed, and results verify that the proposed unit module can be successfully adopted for the entire SST operation.

• Journal of Power Electronics
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• 제19권2호
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• pp.394-402
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• 2019

This paper proposes a single-phase non-isolated onboard battery charger (OBC) for electric vehicles (EVs) that only uses small film capacitors at the DC-link of the AC-DC converter. In the proposed charger, an isolated DC-DC converter for low-voltage batteries is used as an active power decoupling (APD) circuit to absorb the ripple power when a high-voltage (HV) battery is charged. As a result, the DC-link capacitance in the AC-DC converter of the HV charging circuit can be significantly reduced without requiring any additional devices. In addition, some of the components of the proposed circuit are shared in common for the different operating modes among the AC-DC converter, LV charging circuit and active power filter. Therefore, the cost and volume of the onboard battery charger can be reduced. The effectiveness of the proposed topology has been verified by the simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.343-350
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• 2006

This paper introduces a new high efficient bi-directional, non-isolated DC/DC converter. Through variations of the topology of the conventional Cuk converter, an optimum bi-directional DC/DC converter is proposed. Voltage and current in the proposed DC/DC converter are continuous. Furthermore, the efficiency in both step-up and step-down mode is improved over that of the conventional bi-directional converter. To prove the validation for the proposed converter, simulations and experiments are executed with a 300W bi-directional converter.