• Journal of IKEEE
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• v.27 no.4
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• pp.450-455
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• 2023

Among single-phase photovoltaic inverters that can avoid excessive leakage current caused by the large parasitic capacitance of photovoltaic panels, a boost converter followed by a half-bridge inverter is the simplest and has the smallest leakage current. However, due to the high DC-link voltage, the rated voltage of the switching devices is high and the switching loss is large. This paper proposes a new circuit topology which can operate as a buck-boost inverter by adding two bidirectional switches to the output side of the half-bridge inverter instead of removing the boost converter. By reducing two stages of power conversion through the high-voltage DC-link to one stage, power loss can be reduced without increasing costs and leakage current. The feasibility of the proposed circuit topology is verified by computer simulation and power loss calculation.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1348-1350
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• 2002

This paper describes an efficient comparison of the different factor both transformer and inductor. And also the 3 kW class inverter was fabricated for the analysis of the Photovoltaic(PV) power system's performance. The result of the performance of the 3 kW inverter showed that the total harmonics distortion(THD) was 3.19%, the conversion efficiency of the inverter was above 90 % at an over half load, respectively.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1951-1953
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• 2004

In this study, we propose a small high voltage power supply which use a half-bridge ZCS resonant and Cockroft-Walton on circuit, for ESP (Electrostatic Precipitator). This power supply transfers energy from ZCS resonant inverter to step-up transformer and the transformer secondary is applied to the Cockroft-Walton circuit for generating high voltage as discharging source of electrodes. It is highly efficient because its amount of switching losses are reduced by virtue of the current resonant half-bridge inverter, and also due to the small size, low parasitic capacitance in the transformer stage owing to the low number of winding turns of the step up transformer secondary combined with the Cockroft-Walton circuit. From these results, the best operational condition is obtained at the switching frequency of 9 kHz and the duty ratio of 50 % in this ESP.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.76-81
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• 2002

In high power motor drive system, the hard-switching topology produces severs switching losses and EMI noises. Also the inverter switching frequency is thus limited because of excessive loss and thermal handling problem. The primary purpose of the proposed works on the induction motor drive system is to develop an advanced soft-switching inverter topology that is most suitable for high power induction motor drive applications. To make the optimal selection EMI comparison of the switching losses presented. To verify the proposed design procedure, detailed simulation analysis with theoretical and experimental approaches have been done using laboratory prototype.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1392-1401
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• 2015

Inverter configurations for multiple-load induction cooking applications need development. Inverter configurations for induction cooking applications are used in home appliances based on single coil inverters. For multiple-load configurations, multiple coils are used. They require proper inverters, which provide independent control for each load and have fewer components. This paper presents a three-leg inverter configuration for three load induction cooking applications. Each induction coil powers one induction cooking load. This configuration operates with constant switching frequency and powers individual loads. The output power of the required load is controlled with a phase-shift control technique. This configuration is simulated and experimentally tested with three induction loads. The simulation and experimental results are in good agreement. This configuration can be extended to more loads.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.450-454
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• 1994

From a point of view in energy saving and improvement of productivity, inverter for large power induction motor drive is very important. In this thesis, we developed high voltage inverter for large power induction motor drive. We experimented the inverter with R-L series load, successfully, and are going to do the field test in the real plant.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.465-470
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• 1999

This paper presents a design method of driving system for EV(Electric Vehicle). EV driving system consist of batteries, battery interface system and inverter. The power control circuit of the driving system is simple, since only one PWM(Pulse Width Modulation) inverter is used. These test spectrums and waveforms can be used to determine the filter component ratings as well as to compute the harmonics injected into the source. The hybrid control strategy which can reduced harmonic components. The analysis results indicate that the required capacity of the condenser can be reduced with LC filter. In this paper, the design and implementation of the proposed systems are described and some experimental results are given to show the performance of this driving system. The control strategy of the system to available inverter's power and motor's power and torque is discussed.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.149-152
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• 2001

A Single-phase bi-directional inverter Using a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is Presented. It is shown that the ZACE(Zero Average Current Error) algorithm based polarized ramptime current control can provide a suitable interface between diode bridge-type resonant circuit DC link and the inverter. The current control algorithm is analyzed about how to design the circuit with analyzed switch which m ZVT operation for the main power switch The simulation and experimental results would be shown to verify the proposed current algorithm, because the main power switch is turn on with ZVT and the bi-directional inverter is operated.

• Journal of Power Electronics
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• v.14 no.2
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• pp.383-391
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• 2014

For the digital control of systems such as grid-connected inverters, measuring inverter output currents accurately is essential. However, current measurement offsets are inevitably generated by current measurement paths and cause DC current components in real inverter output currents. Real inverter output currents with DC components cause the DC-link capacitor voltage to oscillate at the frequency of a utility voltage. For these reasons, current measurement offsets deteriorate the overall system performance. A compensation strategy to eliminate the effect of current measurement offsets in grid-connected inverters is proposed in this study. The validity of the proposed compensation strategy is verified through simulations and experiments. Results show that the proposed compensation strategy improves the performance of grid-connected inverters.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.294-297
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• 2018

This paper analyzes the losses of the switching device for a full bridge inverter connected to the grid. As the development of power conversion system, losses are dominant factors in judging the efficiency of a system. The losses of a switching device can be divided into switching loss and conduction loss, both of which can be estimated by analyzing periodic switching waveform. The switching loss is generated when the switch is turned on and off, while the conduction loss is generated when the switch is turned on. The estimated losses of the MOSFET switch are compared with the simulation results.