• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.397-398
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• 2016

This paper analyzes switching losses, efficiency and temperature depending on Si and SiC devices applied in two stage AC-DC converter. To evaluate the charge and discharge performance and stability of the battery pack, there is a need for a battery pack testing system. To do battery charge and discharge experiment used in battery pack test, A topology, two stage AC-DC converter, has been built. SiC devices more decrease switching losses than that of Si. Also, cooling system was applied in Si and SiC devices. When using SiC devices, it can be confirmed that the size of heat sink is reduced for small loss.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.518-520
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• 1996

High frequency switching converters are becoming more popular because of several benefits which are essential in power conversion system. This paper introduces a high speed digital controller using TMS320C40 DSP chip which can be used for high frequency switching converters and demonstrates its performance by operating three-phase PWM AC/DC converter with unity power factor at 20kHz sampling frequency. TMS320C40 DSP chip operates with 40-ns instruction cycle times and is capable of 275 MOPS. The running time of real time control loop at the three-phase PWM AC/DC converter is $44.6{\mu}sec$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.96-102
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• 2015

This paper presents battery charging method using 3-phase AC-DC boost converter. General battery charging method is that charging the battery voltage to the reference voltage according to the constant current(CC) control, when it reaches the reference voltage, charging the battery fully according to the constant voltage(CV) control. However, battery chaging time is increased because of the battery impedance, constant current charging section which shoud take the large amount of charge is narrow, and constant voltage charging section which can generate insufficient charge is widen. To improve this problem, we proposes the method to reduce the charging time according to the SOC(State of Charge) estimation using battery impedance.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.501-507
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• 2001

In this paper, new high-efficiency zero voltage switching (ZVS) AC-DC boost converter is proposed to achieve power factor correction by simplifing energy recovery circuit. A lot of high power factor correction circuits have been proposed and applied to increase input power factor and efficiency. Most of these circuits may obtain unity power factor and achieve sinusoidal current waveform with zero voltage or/and zero current switching. However, it is difficult for them to obtain low cost, small size, low weight, and low noise. The topology proposed to improve these problems can compact the devices in circuit and can achieve high efficiency ZVS AC-DC boost converter. Simulation and experimental results show that this topology is capable of obtaining high power factor and increasing the efficiency of the system.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.172-175
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• 2005

Recently international regulations governing the amount of harmonic currents(e.g IEC 61000-3-2) became mandatory and active Power factor correction (PFC) pre-regulator circuit became inevitable for the AC/DC converters. Among these topologies, the boost topology represents an optimum solution for a PFC pre-regulation in a high power application. This paper propose improved ZVT(Zero Voltage Transition) AC/DC PFC Boost using the average current control employing a soft-switching technique of the auxiliary switch with a minimum number of components. The conventional ZVT PFC Boost Converter has a disadvantage that the auxiliary switch turns off hard, which influences the overall efficiency and the EMI problem. In this paper, an improved ZVT PFC Boost converter using active snubber is proposed to minimize the switching loss of the auxiliary. The prototype of 100kHz, 640W system was implemented to show the improved performance.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.363-364
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• 2017

This paper analyzes switching losses and efficiency depending on SiC and Si devices applied in 3-phase AC/DC Converter for Battery Pack Testing System. The switch elements of the 3-phase AC/DC Converter is compared to Si and SiC-based elements and analyzed through comparison of each switching loss by simulation results.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.314-317
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• 1997

The purpose of this study is developing a converter which is able to convert a 300[KW] power, and is a DC power supply output a 1500[V] DC voltage for inverter driving. The power converter is driven by two converter serisely and keep a high power factor of power source. This system is haven all the characteristic of voltage source converter by having a processing ability of regenerating power. The two converters controls a PWM modulation and output voltage using a only one 16 bit DSP processor.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.4
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• pp.377-383
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• 1999

A new soft switching single stage AC-DC full bridge boost converter with unit input power factor and isolated output i is presented in this paper. Due to the use of a non-dissipative snubber on the primary side, a single stage high-power f factor isolated full bridge boost converter has a significant reduction of switching losses in the main switching devices. The non-dissipative snubber adopted in this study consists of a snubber capacitor Cr, a snubber inductor Cr, a fast r recovery snubber diode Dr' and a commutation diode Dp. This paper presents the complete operating principles, t theoretical analysis and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1737-1742
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• 2012

The scott transformer is used to supply single-phase power to the AC railway system. Since the scott transformer is a passive facility, it cannot regulate load-side voltage according to load change. Meanwhile, the Voltage Source Converter (VSC) is able to convert the voltage and control active and reactive power. In this paper, the feasibility of a AC railway system based on Back-to-Back (BTB) VSC which is composed of a rectifier, a DC-DC converter, a inverter, has been proposed. A three-phase to single-phase BTB VSC is modeled. The proposed AC railway system based on BTB VSC is tested on Matlab/Simulink.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.112-115
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• 2002

Previous AC/DC PFC Boost Converter perceives feed forward signal of input and feedback signal of output for average current-mode control. Previous Boost Converter, the quantity of input current will be decreased by the decrease of output current in light load, and also power factor comes to be decreased. Also the efficiency of converter will be decreased by the decrease of power factor. The proposed converter presents the good PFC(Power Factor Correction), low line current hormonic distortions and tight output voltage regulations using non-dissipative snubber. The proposed converter also has a high efficiency by non-dissipative snubber circuit. To show the superiority of this converter is verified through the experiment with a 640W, 100kHz prototype converter.