• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.421-422
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• 2015

Nowadays, bidirectional DC-DC converters are becoming more into picture for different applications especially electric vehicles. There are many bidirectional DC-DC converters topologies; however, voltage-fed Dual Half-Bridge (DHB) topology has less number of switches as compared to other isolated bidirectional DC-DC converters. Furthermore, voltage fed DHB has galvanic isolation, high power density, reduced size, high efficiency and hence cost effective. Electrolytic capacitors always have problem regarding size and reliability in DC-AC single phase inverters. Therefore, voltage-fed DHB converter is proposed for the purpose of power decoupling to replace electrolytic capacitor by film capacitors. A new control strategy has been developed for 120Hz ripple rejection, and it was verified by simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.307-314
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• 1998

A novel high power factor Dual Half Bridge Series Resonant Inverter (DHB-SRI) for an induction heating appliance with multiple loads is proposed to remove the interferential acoustic noise caused by the difference between operating frequencies of adjacent loads. The circuit enables independent full power range control of two induction heating elements by one inverter circuit and has minimum switching losses due to the zero voltage switching characteristic. According to the mode analysis, I will explain the operation of the proposed circuit. To evaluate the required cooling capacity, loss analysis is performed through deriving some loss equations. In order to obtain the power factor correction capability and to lessen the system size, suitable design guides are given. Using the designed values, the proto-type circuit with 2.8kW power consumption for each induction heating element is built and tested to verify the operation of the proposed circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.67-75
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• 2013

In this paper, parallel input/serial output dual converter is designed appropriately for fuel cell hybrid power system. In case of proposed converter, zero voltage switching condition is designed without additional resonance device using leakage inductance of transformer and output capacitance of switch, and zero voltage switching method is used. Also, the system method is for increasing power by connecting half-bridge in parallel and increasing output voltage by connecting secondary output of transformer in serial. Through this method we can increase power and decrease volume of system. So in this paper, dual converter is designed. 1.5kW fuel cell hybrid power system was implemented, and system operation and stability was verified through experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.8
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• pp.719-726
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• 2008

In this paper, we designed driving IC for 500 V resonant half-bridge type power converter, In this single-ended level shifter, chip area and power dissipation was decreased by 50% and 23.5% each compared to the conventional dual-ended level shifter. Also, this newly designed circuit solved the biggest problem of conventional flip-flop type level shifter in which the power MOSFET were turned on simultaneously due to the large dv/dt noise. The proposed high side level shifter included switching noise protection circuit and schmmit trigger to minimize the effect of displacement current flowing through LDMOS of level shifter when power MOSFET is operating. The designing process was proved reasonable by conducting Spectre and PSpice simulation on this circuit using 1${\mu}m$ BCD process parameter.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.486-496
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• 2016

The voltage unbalance of an LVDC bipolar distribution system was controlled for high power quality. Voltage unbalance may occur in a bipolar distribution system depending on the operation of the converter and load usage. Voltage unbalance can damage sensitive load and lead to converter accidents. The conditions that may cause voltage unbalance in a bipolar distribution system are as follows. First, three-level AC/DC converters in bipolar distribution systems can lead to voltage unbalance. Second, bipolar distribution systems can be at risk for voltage unbalance because of load usage. In this paper, the output DC link of a three-level AC/DC converter was analyzed for voltage unbalance, and the bipolar voltage was controlled with algorithms. In the case of additional voltage unbalance according to load usage, the bipolar voltage was controlled using the proposed converter. The proposed converter is a dual half-bridge converter, which was improved from the secondary circuit of a dual half-bridge converter. A control algorithm for bipolar voltage control without additional converters was proposed. The balancing control of the bipolar distribution system with distributed power was verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.419-426
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• 2002

A new active lossless snubber for half-bridge dual converter(that is called'dual converter') is proposed in this paper It features soft switching(ZVS) as well as turn-off snubbing in both main and auxiliary switches. Therefore, it helps the dual converter to operate at the higher frequency with a higher efficiency and smaller-sized reactive components. Moreover, since it uses parasitic components, such as leakage inductances and switch output capacitances etc, to achieve the ZVS of power switches, it has simpler structure and lower cost of production. The operational principle, theoretical analysis, and design consideration are presented. To confirm the operation, features, and validity of the proposed circuit, experimental results from a 200w, 24V/DC-200V/DC proto-type are presented.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.523-531
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• 2014

Brushless Dual-Mechanical-Port Electrical Machine (BLDMPEM) is a new type of motor designed for Hybrid Electric Vehicle (HEV), which contains two mechanical ports and two electric ports. Compared with Dual-Mechanical-Port Electrical Machine (DMPEM), the brushless structure brings higher reliability and easier maintenance. In this paper, the model of BLDMPEM is discussed. In Chapter 2, the energy flow and mathematical model of BLDMPEM are analyzed. Then a novel three-phase half-bridge controlled rectifier topology and its control strategy for cruising mode of HEV based on BLDMPEM are proposed in Chapter 3. Compared with the Field Oriented Control (FOC) strategy of BLDMPEM, the proposed method does not require accurate motor parameters, and it is much simpler and easier to be implemented. At last, simulation and experiment results show the feasibility and validity of the proposed strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.756-762
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• 2009

This paper proposes a high efficient Dual Buck Inverter design with a zero voltage switching (ZVS) control technique. The ZVS control is realized by adding a feedback loop circuit which is implemented by simple RS latch and TTL gate. The used load was 200W -Ceramic Metal Halide Lamp. The experimental results show that the proposed Inverter system could avoid the acoustic resonance and achieve high efficiency by Zero Voltage Switching.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2224-2236
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• 2014

The performance of an isolated high voltage full bridge converter is improved using a voltage doubler. In a conventional high voltage full bridge converter, the diode of the transformer secondary voltage undergoes a voltage spike due to the leakage inductance of the transformer and the resonance occurring with the parasitic capacitance of the diode. In addition, in the phase shift control, conduction loss largely increases from the freewheeling mode because of the circulating current. The efficiency of the converter is thus reduced. However, in the proposed converter, the high voltage dual converter consists of a voltage doubler because the circulating current of the converter is reduced to increase efficiency. On the other hand, in the proposed converter, an input current is distributed when using parallel input / serial output and the output voltage can be doubled. However, the voltages in the 2 serial DC links might be unbalanced due to line impedance, passive and active components impedance, and sensor error. Considering these problems, DC injection is performed due to the complementary operations of half bridge inverters as well as the disadvantage of the unbalance in the DC link. Therefore, the serial output of the converter needs to control the balance of the algorithm. In this paper, the performance of the conventional converter is improved and a balance control algorithm is proposed for the proposed converter. Also, the system of the 1.5[kW] PCS is verified through an experiment examining the operation and stability.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.