• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.385-387
• /
• 1996

A novel two stage soft-switching ac-to-dc convener with power factor correction is proposed. The proposed convener provides zero-voltage-switching (ZVS) condition to main switch of boost pre-regulator without auxiliary switch. Comparing to the conventional two stage approach(ZVS-PWM boost rectifier followed by off-line ZVS dc-dc step down converter), the proposed approach is simple and reducing EMI noise problem. A new simple DC-linked energy feedback circuit provides zero-voltage-switching condition to boost pre-regulator without imposing additional voltage and current stresses and loss of PWM capability. Operational principle, analysis, control of the proposed converter together with the simulation results of 1KW prototype are presented.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.461-463
• /
• 1996

A FB-ZVS(Full Bridge Zero Voltage Switching) PWM DC/DC converter for electric vehicles is analyzed in this paper. The converter considered is a step-down DC/DC converter with the ratings of 3l2/I3.5V and 1.35kW. The steady state analysis of this converter is divided into six operating modes. Digital simulations using PSPICE are carried out to verify the steady-state analysis.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.352-357
• /
• 2003

A new single stage power factor correction(PFC) AC/DC converter based on zero voltage switching(ZVS) full bridge topology is proposed. Since the series-connected two transformers act as both output inductor and main transformer by turns, the proposed converter has a wide ZVS range without additional devices for ZVS. Furthermore, since there is no need to use an output inductor, the proposed converter features high power density. The proposed converter gives the good power factor correction and low line current harmonics distortion. A mode analysis and experiment results are presented to verify the validity of the proposed converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.6
• /
• pp.564-571
• /
• 2001

This paper presents the VLSI design of highly efficient low voltage DC/DC converter for portable devices. All active devices are integrated on a single chip using a standard 0.65$\mu\textrm{m}$ CMOS process. The converter operates at the switching frequency of 1MHz for reducing the size of passive elements and uses a ZVS for minimizing the switching loss at high frequency. Simulation results show that the circuit can achieve a 95% efficiency when the output voltage is controlled to be 2V with the load of lW.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.372-375
• /
• 2000

본 논문은 대용량에 적합한 직·병렬 구조를 가지는 공진형 고압 DC 전원장치에 대한 것이다 이 장치는 전력소자(IGBT)가 스위칭 할 때 발생하는 스위칭 손실과 EMI를 감소시키기 위해서 UC3879를 이용한 영전압 스위칭 (ZVS; Zero Voltage Switching)방식을 채택하였고 영전압 스위칭 위상차제어 직렬 공진형(ZVS PCS-SPI ; ZVS Phase Shifted Control Series Resonant Inverter)으로 동작시켜 고압변압기의 누설 인덕터와 기생 캐패시터를 이용하여 승압이 효과적으로 일어나도록 하였다 또한 고압부는 입력과 효과적으로 일어나도록 하였다 또한 고압부는 입력과 출력부분이 각각 병렬과 직렬로 구성되어 있어서 각각의 모듈이 독립적인 ZVS가 일어나도록 하여 대용량화가 용의 하도록 하였다 본 논문에서10kV/60kW급의 대용량 고압 DC 전원 장치를 구성하여 이를 증명하였다.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1835-1841
• /
• 2017

An improved single-phase full-bridge zero-voltage-switching inverter using a subtractive coupled magnetics is proposed in this paper. The proposed topology overcomes several drawbacks of the conventional ARCPI zero-voltage-switching inverter including two bulky capacitors which can cause problems such as the need for a protection circuit and voltage fluctuation of split capacitors. Also the proposed topology can reduce the number of devices required for ZVS through a simplified auxiliary circuit, thus achieving low cost and small volume and is applicable a modified unipolar PWM scheme. Detail mode analysis and design considerations are provided for optimal efficiency. In the end, the effectiveness and feasibility of the proposed topology are verified experimentally under various conditions.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.517-519
• /
• 2008

A new transformer winding method is proposed in this paper. Generally, PWM ZVS topologies use a leakage inductor to achieve ZVS operation. However, the leakage inductance of the transformer is not often enough to meet ZVS condition. Therefore, an additional leakage inductor is necessary, which causes large core loss because high input voltage is applied to the additional leakage inductor during a short commutation period. In this paper, a new separated leakage inductor winding (SLW) method is proposed. With the proposed winding method, a leakage inductor and a transformer can be combined in one ferrite core. Therefore, size and core loss of the additional leakage inductor can be reduced. Experimental results demonstrate that the proposed winding method can achieve a significant efficiency improvement in a 1210.8W (12V, 100.9A) prototype converter.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.939-941
• /
• 2001

An efficient control method of ZVS Full-bridge PWM converter with a periodic pulsed-load current is proposed. This novel control method can reduce the switching loss of switches during no load condition. Moreover, by using feed-forwarded load current information this method can obtain better transient dynamics compared to the system with only linear feedback control.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.1
• /
• pp.64-69
• /
• 2003

There exist the high frequency components, which can not be predicted by the low frequency model, due to the presence of sampling effect in current mode control. In this paper, the output voltage equations for the ZVS half bridge PWM convertor are derived from the steady state analysis, and the sampling gain presented in the current control loop is Investigated to improve the Prediction Performance of low frequency model of ZVS half bridge PWM converter.

• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2674-2677
• /
• 1999

Resonant converters have several salient features such as high efficiency and low noise. Therefore, ZVS-PWM controlled series resonant converter with active-clamp technique is presented. The combination of an active-clamp technique and resonant circuit makes it possible to control the output voltage of the resonant converter with PWM. This new resonant converter was implemented and has achieved a good controllability. In this paper, the normal load characteristics and abnormal voltage increase in the case of the light load are analyzed. As a result, it is clarified that the stray capacitance of the transformer is a cause of the abnormal voltage increase. Then, it is confirmed that the abnormal voltage increase is suppressed by decreasing the duty ratio. ZVS condition is analyzed. The maximum efficiency of 89% is obtained for the output of 10V and 5A.