• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.43-44
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• 2017

This paper presents design of auxiliary circuit to reduce loss of ZVT interleaved flyback converter. The ZVT interleaved converter using the conventional auxiliary circuit has a large conduction loss due to the constant circulating current in the auxiliary circuit. The auxiliary circuit proposed in this paper, which consists of the coupled inductor and DC-link capacitor, has linearly increasing or decreasing auxiliary current. Then, the conduction loss occurring in the auxiliary circuit is reduced. The validity of the proposed auxiliary circuit is verified with the prototype of 500W.

• Journal of Power Electronics
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• v.18 no.3
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• pp.681-693
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• 2018

This paper proposes a soft-switching bidirectional dc-dc converter (BDC) with an auxiliary circuit. The proposed BDC can achieve the zero-voltage switching (ZVS) using an auxiliary circuit in the buck and boost operations. The auxiliary circuit supplies optimal energy for the ZVS operation of the main switches. The auxiliary circuit consists of a resonant inductor, a back-to-back switch and two capacitors. A small-sized resonant inductor and an auxiliary switch with a low-rated voltage can be used in the auxiliary circuit. Zero-current switching (ZCS) turn-on and turn-off of the auxiliary switches are possible. The proposed soft-switching scheme has a look-up table for optimal switching of the auxiliary switches. The proposed strategy properly adjusts the turn-on time of the auxiliary switch according to the load current. The proposed BDC is verified by the results of PSIM simulations and experiments on a 3-kW ZVS BDC system.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.249-254
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• 1998

This paper describes the control methods to cut out the NFB(No Fuse Breaker) of shorted load in the auxiliary power supply, Generally, when the short-circuit occurs in the load of the auxiliary power supply, the auxiliary power supply stops the operation according to the protection sequence. Finally, the other auxiliary power supply stops the operation by the same fault, To resolve this problem, we suggest the control method to trip the NFB of shorted load. That is, when the short circuit occurs, the controller changes control mode from voltage mode to current mode without the operation of output contactor(SIVK) in the auxiliary power supply. The auxiliary power supply provides a large current for the short-circuit load. After some time, the NFB of the short-circuit load is cut off and the auxiliary power supply Provides stable voltage for the loads except for the short-circuit load.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1611-1618
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• 2018

This paper proposes a new auxiliary resonant commutated pole (ARCP) inverter which has a modified auxiliary circuit. The proposed auxiliary circuit includes two auxiliary IGBT switches, an LC resonant circuit, and two clamping diodes. In order to analyze the performance of proposed ARCP inverter, computer simulations with PSCAD, and hardware experiments were carried out. Through analyzing the experimental results, it is known that the proposed ARCP inverter offers efficiency improvement of 1.5% compared with the hard-switching inverter.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.49-58
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• 2005

A new soft switching three-phase PWM rectifier with simple circuit configuration and high efficiency has been developed. The proposed circuit is a kind of the auxiliary resonant commutated Pole(ARCP)converter The conventional ARCP converter requires three-auxiliary reactors and six-auxiliary switches for the soft switching auxiliary circuit and for these switching elements, a gate drive circuit and a control circuit are required, resulting in high part as a disadvantage. In the main circuit proposed in this paper, the auxiliary soft switching circuit is composed of two-auxiliary reactors, two-auxiliary switches and several diodes. In addition, common use of the PWM control circuit for two-switches will make the control circuit of the auxiliary switches simple. By means of function of the soft switching auxiliary circuit, the main switching element performs zero voltage switching operation and the auxiliary switches perform the zero current switching. In this paper, the circuit configuration and the operational analysis of the proposed circuit are described at first and then, experimental results will be reported. By using a prototype with 5[kW] capacity, the conversion efficiency of maximum $98.8[\%]$ and the power factor of $99[\%]$ or higher were obtained.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.547-555
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• 2013

This paper proposes the interleaved buck converter using a soft switching auxiliary circuit. In this scheme, an auxiliary circuit is added to the conventional interleaved buck converter and used to achieve soft-switching conditions for both the main switch and freewheeling diode. In addition, the switch in the auxiliary circuit operates under soft-switching conditions. Also, according to the input to output conditions, the main switch achieved zero-current-transition(ZCT) or zero-current & zero-voltage-transition(ZCZVT) at turn on. Thus, the proposed interleaved buck converter provides a higher efficiency. The basic operations, in this paper, are discussed and design guidelines are presented. The usefulness of the proposed converter is verified on a 200kHz, 180W prototype converter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.455-460
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• 1999

A novel zero-voltage-transition (ZVT) PWM converter for switched reluctance motor (SRM) drives is proposed. A simple auxiliary circuit which consists of one active switch, one resonant inductor, and three diodes provides ZVS condition to all main switches and diodes allowing high frequency operation of the converter with high efficiency. The auxiliary circuit is placed in parallel with the main power flow path and thus it handles only a small fraction of the main power. So, the power rating of the auxiliary circuit can be very small (about 30% of main power). So, the auxiliary circuit can be realized with small power rating and low cost. Operation, features and characteristics of the proposed converter are illustrated and verified on a 1.5 kW, 50 kHz IGBT based (a MOSFET for the auxiliary with) experimental circuit.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.155-157
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• 2009

This paper proposed a soft switching boost converter with an auxiliary circuit, and a modified control method for reduction of switch stress. The proposed converter applies an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft switching for both a main switch and an auxiliary switch. The auxiliary circuit consist of a resonant inductor and two capacitors, an auxiliary switch. The main switch is operated ZVS turn-on, turn-off also auxiliary switch is operated ZCS turn-on, ZVS turn-off. The proposed soft switching boost converter has lower switch loss and higher efficiency than conventional soft switching boost converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.458-465
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• 2013

This paper proposes a novel soft-switched auxiliary resonant circuit to provide a Zero-Voltage-Transition at turn-on for a conventional PWM boost converter in a PFC application. The proposed auxiliary circuit enables a main switch of the boost converter to turn on under a zero voltage switching condition and simultaneously achieves both soft-switched turn-on and turn-off. Moreover, for the purpose of an intelligent multi-chip power module fabrication, the proposed circuit is designed to satisfy several design constraints including space saving, low cost, and easy fabrication. As a result, the circuit is easily realized by a low rated MOSFET and a small inductor. Detail operation and the circuit waveform are theoretically explained and then simulation and experimental results are provided based on a 1.8 kW prototype PFC converter in order to verify the effectiveness of the proposed circuit.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.4
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• pp.298-305
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• 2012

This paper proposes a soft switching boost converter with an auxiliary resonant circuit. The auxiliary resonant circuit is added to a general boost converter and that is composed of one switch, one diode, one inductor and two capacitors. The resonant network helps the main switch to operate with a zero voltage switching(ZVS) and auxiliary switch also operates under the zero voltage and zero current conditions. The soft switching range is extended by the auxiliary switch and it is possible to control the proposed converter with a pulse width modulation(PWM). The ZVS and ZCS techniques make switching losses decreased and efficiency of the system improved. A theoretical analysis is verified through the simulation and experiment.