• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.301-303
• /
• 2001

In this paper we present a Capacitor Charging Power Supply (CCPS) using a series-resonant three-level inverter topology to improve voltage regulation and use semiconductor switches having low blocking voltage capability such as MOSFETs. This inverter can be operated with two modes, Full Power Mode (FPM) and Half Power Mode (HPM). In FPM inverter supplies the high frequency step up transformer with full DC-link voltage and in HPM with half DC-link voltage. HPM switching method will be adopted when CCPS output voltage reaches the preset target value and operates in refresh mode-charge is maintained on the capacitor. In this topology each semiconductor devices blocks a half of the DC-link voltage[2]. A 15kW, 30kV CCPS has been built and will be tested for an electric precipitator application. The CCPS operates from an input voltage of 500VDC and has a variable output voltage between 10 to 30kV and 1kHz repetition rate at 44nF capacitive load [3]. A resonant frequency of 67.9kHz was selected and a voltage regulation of $0.83\%$ has been achieved through the use of half power mode without using the forced cut off the switch current [1]. The theory of operation, circuit topology and test results are given.

• Journal of Power Electronics
• /
• v.17 no.5
• /
• pp.1256-1267
• /
• 2017

A fault tolerant structure and its corresponding control strategy for electromagnetic stirring power supplies are proposed in this paper. The topology structure of the electromagnetic stirring power supply contains two-stages. The fore-stage is the PWM rectifier. The back-stage is the fault tolerant inverter, which is a two-phase three-bridge orthogonal inverter circuit while operating normally. When the power switch devices in the inverter are faulty, the structure of the inverter is reconfigured. The two-phase half bridge inverter circuit is constructed with the remaining power switch devices and DC-link capacitors to keep the system operating after cutting the faulty power switch devices from the system. The corresponding control strategy is proposed to let the system work under both normal and fault conditions. The reliability of the system is improved and the requirement of the electromagnetic stirring process is met. Finally, simulation and experimental results verify the feasibility of the proposed fault tolerant structure and corresponding control strategy.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.174-177
• /
• 2005

Offline switching power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.217-221
• /
• 2006

Offline switching Power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.11
• /
• pp.561-568
• /
• 2005

This paper proposes a method that distributes the load power and stores the regenerated energy for a hoist-load system using the supercapacitor, an energy storage device. The crane, which is a representative hoist-load system, operates in two modes. The first is the hoist-up mode in which the load container is lifted up: the maximum power is required at the end of acceleration. The second is the hoist-down mode in which the load container is lifted down; the regenerated energy is wasted by the resistor In this paper, the supercapacitor stores the regenerated energy in the hoist-down operation and supplies the peak power demand in the hoist-up operation. The same structure as the commercially available three-phase inverter is proposed as a bidirectional do-dc converter to charge and discharge the supercapacitor. A power control algorithm is proposed to optimize the load sharing between the generator and the supercapacitor. Using the proposed method, it is effected that the generator size can be cut down to one third of the original one; it leads to the reduction of the fuel consumption, noise and air pollution. Simulation and experimental results verify the effectiveness of the Proposed method.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.6
• /
• pp.697-705
• /
• 2014

A single chip Programmable AC to DC Power Converter, consisting of wide band gap SiC MOSFET and SiC diodes, has been proposed which converts high frequency ac voltage to a conditioned dc output voltage at user defined given power level. The converter has high conversion efficiency because of negligible reverse recovery current in SiC diode and SiC MOSFET. High frequency operation reduces the need of bigger size inductor. Lead inductors are enough to maintain current continuity. A complete electrical analysis, die area estimation and thermal analysis of the converter has been presented. It has been found that settling time and peak overshoot voltage across the device has reduced significantly when SiC devices are used with respect to Si devices. Reduction in peak overshoot also increases the converter efficiency. The total package substrate dimension of the converter circuit is only $5mm{\times}5mm$. Thermal analysis performed in the paper shows that these devices would be very useful for use as miniaturized power converters for load currents of up to 5-7 amp, keeping the package thermal conductivity limitation in mind. The converter is ideal for voltage requirements for sub-5 V level power supplies for high temperatures and space electronics systems.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.384-387
• /
• 2009

There is an increasing demand for efficient high power/weight auxiliary power supplies for use on high speed traction application. Many new conversion techniques have been proposed to reduce the voltage and current stress of switching components, and the switching losses in the traditional pulse width modulation (PWM) converter. Especially, the phase shift full bridge zero voltage switching PWM techniques are thought must desirable for many applications because this topology permits all switching devices to operate under zero voltage switching(ZVS) by using circuit parasitic components such as leakage inductance of high frequency transformer and power device junction capacitance. The proposed topology is found to have higher efficiency than conventional soft-switching converter. Also it is easily applicable to phase shift full bridge converter by applying an energy recovery snubber consisted of fast recovery diodes and capacitors.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.1
• /
• pp.81-86
• /
• 2019

This paper is concerned with a system design that enables a the plurality of switching mode power supplies to be supplied with larger power through a parallel connection. For this purpose, a shunt resistor is placed in series at the output of the constant voltage regulator and the output voltage is sensed and controlled using an arduino. In this paper, two constant-voltage regulators were used for the experiment, but it is possible to generalize for more boards. By using the method that controls the system, the sum of the currents delivered by the two systems to the load was found to be 96% of the current drawn from each board. In case of efficiency, 92.4% efficiency is achieved in the unit board and the efficiency in parallel connection is about 90%.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.10
• /
• pp.133-137
• /
• 2016

Use of UV gel for nail management have been increasing gradually. In order to develop an UV lamp necessary to UV gel, in this study, we was designed circuits of the UV-LED lamp. Power supply part that supplies constant power to the several UV-LEDs, was designed the circuit with the method of DC-DC converter. Taking into account the direction of the thumb nail and the position of the little finger nail, it was placed UV-LEDs. Input power of the power supply part was used as a battery voltage of 3.8[V]. The output voltage of the power supply part was appeared in approximately 3.1[V]. And in order to examine the state of change of the output voltage according to the amount of current consumption of UV-LEDs, after inserting of load resister, the output voltage was more than about 3.0[V] in the simulation results of the power supply part while changing the resistance value.

• Proceedings of the KIPE Conference
• /
• 2012.11a
• /
• pp.52-53
• /
• 2012

This paper presents a new control scheme for a three-phase split DC-link capacitor inverter as an AC power supplies. The proposed control method can maintain the balanced sinusoidal output voltage under unbalanced and nonlinear load conditions. The validity of the control method has been verified by simulation results.