• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.26-27
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• 2011

This paper focuses on the zero-voltage/zero current transition voltage equalization circuit for the series connected battery cell. By adding auxiliary resonant cells at the main switching devices such as MOSFET or IGBT, zero current switching is achieved and turned off loss of switching elements is eliminated and by the voltage/second balancing of the inductor, zero voltage switching can be applied to switching element. Transformer coupling between battery cells and ZVZCT (Zero Voltage Zero Current Transition) switching method allow the fast balancing speed and high frequency operation, which reduces the size and weight of the circuit. The validity of the battery equalization is further verified using simulation involving four lithium-ion battery cell models.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.294-298
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• 2003

In this paper, the new zero-current-transition (ZCT) circuit cell is proposed. The main switch is turned-off under the zero current and zero voltage condition, and there is no additional current stress and voltage stress in, the main switch and the main diode. The Auxiliary switch is turned-off under the zero voltage condition, and the main diode is turned-on under the zero voltage condition, The resonant current required to obtain the ZCT is small and regenerated to the input voltage source. The operational principles of the boost converter integrated with the proposed ZCT circuit cell is analyzed theoretically and verified by the simulation and experimental result. Index terms - zero-current-transition (ZCT), zero-current- switching (ZCS), zero-voltage-switching (ZVS)

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2148-2150
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• 1998

This paper proposes a constant frequency controlled zero voltage switching method that can reduce switching losses caused by emf on inductance in DC motor. The zero voltage switching method is used more than a zero current switching method because of reducing switching losses by capacitance of depletion region of MOSFET. To simplify the controller circuit, we propose constant frequency controlled zero voltage switching method in the paper. The control method is more stable than a variable frequency control method because it can optimize bandwidth of a closed-loop and reactances. Therefore, we construct a constant frequency controlled zero voltage switching converter and improve zero switching losses in high switching frequency. In the process, we can control low-losses in full range on variable voltage and load. We simulate the proposed converter with P-SPICE and compare results obtained through the experiment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1998.11a
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• pp.120-124
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• 1998

In this paper, new zero voltage and zero current switched PWM(Pulse Width Modulated) converters are suggested. The main and auxiliary switch of the converters satisfy soft switching conditions, which are zero voltage or zero current switching of the switches. The switching characteristics of the proposed converters are experimentally verified by boost typed converter, which has 250 kHz switching frequency. For the 250 kHz operation, turn on period of auxiliary switch is about 1/40 for switching period of 4 ${\mu}\textrm{s}$. Therefore, the conduction loss of auxiliary switch is reduced.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.256-262
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• 2018

This study introduces a novel Soft Switching (SS) Pulse Width Modulated (PWM) AC-DC boost converter. In the proposed converter, the main switch is turned on with Zero Voltage Transition (ZVT) and turned off with Zero Current Transition (ZCT). The main diode is turned on with Zero Voltage Switching (ZVS) and turned off with Zero Current Switching (ZCS). The auxiliary switch is turned on and off with ZCS. All auxiliary semiconductor devices are turned on and off with SS. There is no extra current or voltage stress on the main semiconductor devices. The majority of switching energies are transferred to the output by auxiliary transformer. Thus, the current stress of auxiliary switch is significantly reduced. Besides, the proposed converter has simple structure and ease of control due to common ground. The theoretical analysis of the proposed converter is verified by a prototype with 100 kHz switching frequency and 500 W output power. Furthermore, the efficiency of the proposed converter is 98.9% at nominal output power.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.119-122
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• 2005

A algorithm for control and performance of a pulse-density-modulated (PDM) series-resonant voltage source inverter developed for corona-dischange precesses is presented. The PDM inverter produces either a square-wave ac-voltage state or a zero-voltage state at its ac terminals to control the average output voltage under constant dc voltage and operating frequency. Moreover it can achieve zero-current-switching (ZCS) and zero-voltage-switching (ZVS) in all the operating condition for a reduction of switching lost. Even though the corona discharge load with a strong nonlinear characteristics, new high frequency resonant inverter is shown the wide range power control from 5% to 100%.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.227-231
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• 2001

A new primary-side-assisted zero-voltage and zero-current switching (ZVZCS) three-level DC-DC converter with flying capacitor is proposed. The three-level converters are promising in high voltage applications, and ZVZCS is a very effective means for reducing switching losses. The proposed DC-DC converter uses only one auxiliary transformer and two diodes to obtain ZCS for the inner leg. It has a simple and robust structure, and offers soft-switching capability even in short-switching conditions. The proposed converter was verified by experiments in a 6KW prototype designed for communication applications and operating at 100kHz.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.438-439
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• 2011

In this paper, soft switching bidirectional DC-DC converter is proposed. The proposed topology is added two auxiliary switches, two resonant capacitors and one resonant inductor to convectional bidirectional DC-DC converter. Therefore, this proposed topology can reduce switching loss of each power switch by ZVS (Zero Voltage Switching) and ZCS (Zero Current Switching). We have performed mode analysis, simulation and experiment for the proposed topology.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.273-279
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• 2015

A zero vector selection method to reduce switching losses for model predictive control (MPC) of voltage source inverter is proposed. A conventional MPC of voltage source inverter has not been proposed, and a method to select the redundancy of the zero vector is required for this study. In this paper, the redundancy of the zero vectors is selected with generating a zero sequence voltage to reduce switching losses. The zero vector of 2-level inverter is determined by determining sign of the zero sequence voltage. In the proposed method, the quality of the current is retained and switching loss can be reduced compared with the conventional method. This result was verified by P-sim simulation and experiments.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1133-1135
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• 1992

This paper describes high frequency inverter using zero voltage switching(ZVS). The ZVS operation is achieved to reduce the switching stress and switching loss under high speed switching. The proposed circuit configuration and performance are discussed. Its operation characteristics are evaluated through computer-aided simulation.