• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.639-643
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• 2018

As electronic systems become smaller and more portable, the need for power conversion continues to increase. In addition, system stability must be ensured from switching noise due to power conversion efficiency and power conversion system miniaturization. Therefore, countermeasures to reduce switching noise during power conversion are essential. In this paper, a DC/DC buck converter circuit is constructed, and the characteristics of switching noise generated when changing the parts layout in a four-layer printed circuit board (PCB) structure with a reference plane are compared and analyzed. In addition, switching noise characteristics were compared and analyzed through simulations when the parts layout was different in a two-layer PCB structure from which the reference planes were removed. As a result, it was confirmed that the radiated emissions characteristic is reduced by 12dB and the conducted emissions characteristic decreased by 7dB to 8dB, according to the current return path in the four-layer PCB structure. Thus, it was confirmed that the noise characteristics can be improved according to the configuration of the current return path when the power conversion circuit is designed.

• Journal of IKEEE
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• v.16 no.4
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• pp.335-342
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• 2012

This paper is studied on a new DCM-ZVS step up-down AC-DC converter of high performance, that is, high system efficiency and power factor correction (PFC). The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit, and are driven with discontinuous conduction mode (DCM) according to pulse width modulation (PWM). The quasi-resonant circuit uses a step up-down inductor and a loss-less snubber capacitor. The proposed converter with DCM also simplifies the requirement of control circuits and reduces the number of control components. The input AC current waveform in the proposed converter becomes a quasi-sinusoidal waveform proportional to the magnitude of input AC voltage under constant switching frequency. As a result, the proposed converter obtains low switching power loss and high efficiency, and its input power factor is nearly in unity. The validity of the analytical findings is confirmed by some computer simulation results and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.183-190
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• 2004

This paper proposes a methodology to solve problems upon the circuit design applied to inductor load by applying a circuit to improve power factor with is partial switching PFC module to the power supply system for cooling/heating inverter air conditioner and by designing an input power section in compliance with IEC555-2 on the basis of better input power factor and minimized harmonic components of current. On the other hand, this paper suggested how to control the increase of output voltage along with tぉw current waves and partial switching PFC circuit as well, which can provide the output as twice as input voltage This study applied a method to control the compressors of air conditioner by means of increased the voltage applicable to compressor motor by lowering switching number conclusively, it could solve questions about efficiency, economics, electronic noise and so forth. and so that the reasonable voltage for running moor could be set up along with lower power consumption of air conditioner than estimated It was demonstrated that total sum of energy efficiency to operate system was increased to the extent of valid level. And all this merits and appropriateness was proved by computer simulation and experience.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1064-1066
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• 2002

This paper proposes a new prototype auxiliary resonant DC link(ARDCL)snubber circuit and deals with its power loss on the basis of actually measured conduction loss characteristic of switching device module. Voltage type soft switching three phase inverter using proposed ARDCL snubber circuit is presented along with its performance evaluations. And, the power loss analysis of three phase hard and soft switching inverter are carried out from the point of simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.493-498
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• 2004

The EMI noise source in a switching mode power supply is dominated by a common mode noise. If we can understand the common mode noise occurring mechanism, it is resulted to find out the method to suppress the EMI noise source in the switching mode power supply. The common mode noise is occurring mostly due to circuit is unbalanced which is caused by the capacitive coupling to frame ground, which passes through a heatsink of the switching devices. This research paper presents a new effective balancing method of buck converter circuit by mean of grounding the parasitic and compensation capacitors in correct proportion which is called that the common mode impedance balance (CMIB). The CMIB can be achieved by source, transmission line and termination balanced, such balancing, the common mode current will be cancelled out in the frame ground. The greatly reduced common mode noise can be confirmed by the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.49-56
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• 2016

In this paper, a prototype of power supply with a power factor correction is proposed. As a unique feature the proposed power supply, a status monitoring circuit is embedded on the switching power supply. The status monitoring circuit analyzes the functionality of the system and saves the key components of the power supply in the case of malfunctions. The results of various fault tests are reported to verify the operation and performance of the proposed method. This paper discusses the experimental results of the monitoring module and provides the technical information to monitor, predict, and troubleshoot the system against the potential failure of power supplies for real applications.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.231-233
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• 1991

This paper discribes a study on the switching character of MOS-GTO and the design of gate drive circuit. Chopping power supply converter, synchronious and asyncronious motor speed adjustment, inverter, etc., needs low drive energy "high frequency" switches. To fulfill these need, switches must have rapid switching time and insulated gate control. MOS-GTO structure is well suited to these constraints. The power switch is serial installation of a GTO thyrister and a MOS Transistor. The gate of the GTO is linked to positive pole of the cascode structure via a MOS high voltage transistor and ground via a transient absorber diode. This high performance MOS-GTO assembly considerably increases the strength which facilitate the drive of GTO thyristers.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.644-649
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• 2001

This paper proposes a soft-switching current -source inverter for photovoltaic power system, which has an H-type switched-capacitor module composed of two semiconductor switches, two diodes, and an L-C resonant circuit. The operation of proposed system was analyzed by a theoretical approach with equivalent circuits and verified by computer simulations with SPICE and experimental works with a hardware prototype. The proposed system could be effectively applied for the power converter of photovoltaic power system interconnected with the power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.44-52
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• 2007

In this study, design and control method using low cost Micro-controller(MCU) for inverter driving circuit in fluorescence lamp is presented. Soft starting technique is adopted to reduce switching loss and moment deterioration which are induced by high speed switching frequency in inverter ballast. Performance of the ballast stabilizer and the lighting characteristic of the fluorescence lamp have been improved by stabilizing switching pulses through the Pulse Width Modulation control.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.3
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• pp.201-205
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• 2010

DC/DC Switching power converters are commonly used to generate regulated DC output voltages with high-power efficiencies from different DC input sources. A switching converter utilizes one or more energy storage elements such as capacitors, or transformers to efficiently transfer energy from the input to the output at periodic intervals. The fundamental boost converter studied here consists of a power metal-oxide semiconductor field effect transistor switch, an inductor, a capacitor, a diode, and a pulse-width modulation circuit with oscillator, amplifier, and comparator. A buck converter containing a switched-mode power supply is also studied. In this paper, the electrical characteristics of DC/DC power converters are simulated by simulation program with integrated circuit emphasis (SPICE). Furthermore, power efficiency was analyzed based on the specifications of each component.