• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.114-121
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• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

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

• Journal of Drive and Control
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• v.17 no.4
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• pp.46-53
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• 2020

In this paper, the development of a manually and continuously variable impact force control mechanism for hydraulic breakers was studied. Generally, a hydraulic breaker has one or two piston strokes. Hydraulic breakers, which have two strokes, have two valve-switching ports and make short and long piston strokes. The piston stroke valve controls the piston stroke by opening and closing a short stroke-switching port. The short piston stroke mode is used to break soft rock, concrete, or asphalt. This stroke control valve system is not popular for small hydraulic breakers mounted on 1 to 14-ton excavators. To preserve the carrier-like excavator, proper breaking force is needed, and it can be easily controlled by multiple piston stroke control valves. The easiest way to control these breakers is to use several switching ports and valves but they are not easy to install in small hydraulic breakers and are expensive. To use only one switching port and valve, a method can be used to change the open area of the switching port to delay valve switching. This method provides multiple piston strokes.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.165-166
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• 2016

본 논문에서는 Common-Mode Noise가 저감된 계통연계형 단상인버터의 파워소자선정에 따른 스위칭 손실 저감을 제안한다. 풀브리지 회로에서 상용전원 레퍼런스 주파수로 상보적인 스위칭 신호를 주는 PWM_1구간에는 비교적 천천히 스위칭하기 때문에 컨덕션 loss가 적은 IGBT를 사용하며, 보다 빠른 스위칭 주파수로 동작하는 PWM_2구간에서는 Switching loss가 적은 MOSFET을 사용하여 전체적인 스위치에서 발생되는 손실을 저감한다.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.287-291
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• 2009

In this paper, an optical switch/modulator is designed and its light propagating characteristics analyzed using a simplified BPM. The distinctive feature of this switch/modulator is that all its waveguide branches are designed as single-mode. The principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of the fact all waveguides are designed as single-mode, by adjusting the interconnecting waveguide length'of the device the same characteristics as existing up to date devices are obtainable. Numerical results show that the switching characteristics periodically depend upon an interconnecting waveguide length with a spatial of about $150^{{\mu}m}$ in the $Ti:LiNbO_3$ step index waveguide. The design concept would therefore be utilized effectively in fabricating a monolithic high density optical integrated circuit.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1126-1128
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• 1992

The object of this study is the design of 3 phase on-board inverter. The key point in the inverter design is the selection of switching device, and its performance effects that of total system. In this study, six-step square wave inverter was designed using IGBT ( Insulated Gate Bipolar Transistor ) which has the advantages of MOSFET and bipolar transistor as switching device. The condition of being small and light which is the one of requirements for on-board equipment was accomplished by using IGBT module and optimising the snubber circuit, and the reliablity was increased. It is confirmed that the designed inverter satisfies the required performance through the performance and environment test.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1129-1132
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• 1992

This paper proposes a high frequency resonant inverter consisting of equivalent half bridge model using MOSFET. In this paper time-sharing control method is applied. as a result the output frequency is two times as high as switching frequency of device, and average current of device is incresed because of decreasing switching loss.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.10
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• pp.625-633
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• 2004

This paper proposed a boost input type single stage resonant power supply for driving magnetron device. The proposed power supply can control both input power factor and output power at the same time. Also, because ZVS is achieved using the resonance between leakage inductance and resonant capacitance, switching losses are drastically reduced. To prevent breakdown or moding phenomenon of the magnetron due to excessive starting voltage, variable frequency ignition method is also proposed. Experimental results for the prototype power supply are presented and discussed to verify the validity of the proposed power supply.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.751-758
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• 2004

This paper presents a new method to compensate the non-linearity for matrix converter drives using PQR instantaneous Power theory. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled by PQR power theory and compensated using a reference current control scheme. The proposed method does not need any additional hardware and off-line experimental measurements. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system without a speed sensor. Simulation and experimental results show the proposed method using PQR power theory Provides good compensating characteristic.

• Journal of IKEEE
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• v.10 no.2 s.19
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• pp.149-155
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• 2006

In this study, the design of low voltage DC-DC converter with low triggering ESD (Electro-Static Discharge) protection circuit was investigated. The purpose of this paper is design optimization for low voltage(2.5V to 5.5V input range) DC-DC converter using CMOS switch. In CMOS switch environment, a dominant loss component is not switching loss but conduction loss at 1.2MHz switching frequency. In this study a constant frequency PWM converter with synchronous rectifier is used. And zener Triggered SCR device to protect the ESD phenomenon was designed. This structure reduces the trigger voltage by making the zener junction between the lateral PNP and base of lateral NPN in SCR structure. The triggering voltage was simulated to 8V.