• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.539-545
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• 2012

Due to merits cost and efficiency, the transformer-less type photovoltaic (PV) inverters have been popularized in the solar market. However, the leakage current flowing through a parasitic capacitor between PV array and ground can cause adverse effect in the transformer-less PV system. In this paper, a bi-directional PV inverter with high efficiency and low noise is proposed for the PV system with an energy storage device. The proposed inverter is a transformer-less type and performs the bi-directional power control between dc sources and grid with high efficiency. In addition, the proposed inverter can suppress the leakage current and obtain low noise characteristic. Finally, 3-kW prototype was implemented to confirm validity of the proposed inverter.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.319-324
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• 2012

This paper presents the study of 3-Phase bi-directional DC to AC inverter with unity power factor. 3-Phase bi-directional DC to AC inverter is important for the bi-modal PV PCS with an energy storage system. Both Inverting and converting are needed to connect between the grid side and boost converting side to charge and discharge the energy storage system. The paper proposes the appropriate circuit topology and proper control system for the bi-directional inverter. It also proposes the method of selecting the optimum control method considering system stability. PSIM simulation is used to validate the proposed algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.10
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• pp.16-26
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• 2014

This paper proposes new 13-level inverter topology and DC/DC converter buck-boost structure topology for multilevel, compounding uni-directional and bi-directional switches, and proposes high-efficient multilevel inverter system in which the proposed two PCS(Power Conditioning System) was connected in series. In proposed multilevel inverter of forming a output 13-level phase voltage by using total 18 switching parts, Then bi-directional switch has a characteristic of reducing conduction loss and controlling the reactive power effectively by separating electrically from the neutral point. DC/DC converter for supplying in dependent 3 DC voltage to the proposed multi-level inverter generates 180-degree phase shifted PWM by the symmetrically combined structure of 2 buck-boost converter and twice switching frequency efficiency can be obtained, meanwhile, the converter can step up/down the output voltage and 20% output can be generated comparing the input voltage. This proposed system is verified with the simulation and laboratory test.

• 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.6 no.2
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• pp.121-130
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• 2006

This paper presents the performance and efficiency of a drive system incorporating a switched-reluctance motor (SRM) with input power factor correction (PFC). The proposed system consists of a PFC, bi-directional converter, an inverter, and a SRM operating as based voltage source drives (VSD). First, theoretical analysis is made for each identified mode of operation in the drive system. This is followed by comparing the performance of the SRM drive system with and without a PFC circuit. The losses are also calculated for both systems and overall efficiency. Experimental results are presented to prove the theoretical analysis.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.309-313
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• 2001

A single-phase bi-directional inverter with a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is proposed. It is shown that the polarized ramptime current control algorithm, a method that belongs to the family of ZACE(Zero Average Current Error) methods, is a suitable technique to integrate with a typical single-phase ZVT inverter. The proposed current control algorithm is analyzed to design the circuit with auxiliary switch which can operate with ZVT for the main power switch. The simulation results would be shown to verify the proposed current algorithm to turn the main power switch on with ZVT and to operate the inverter bi-directionally

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.228-234
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• 2012

This paper presents the algorithm of the compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it sugest simple method to solve the problem. PSIM simulation is used to validate the proposed algorithm.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.551-554
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• 2006

An inverter system which consists of three bi-directional buck-boost converters, is proposed for motor driving. Three phase sinusoidal output voltages can be generated by utilizing three buck-boost converters. The advantage of this scheme is that it does not require a separate DC-DC converter for motor driving, i.e. inverter function is combined into the three DC-DC converters. This topology is suitable for inverters for hybrid or fuel cell vehicles where DC link voltage is subject to change depending upon charging status or output power. So the proposed system is capable of driving motor at high speed. The converter system is controlled by PI controller and simulation results done by MATLAB SIMULINK are provided.Ҙ?⨀ሉȀ̀㘰々K䍄乍?ጊ츀Ѐ㔹〻Ԁ䭃䑎䴀

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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• pp.161-168
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• 2013

This paper presents an algorithm of a compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it suggest simple method to solve the problem. Simulation and experiment is used to validate the proposed algorithm.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.133-139
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• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.