• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2671-2673
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• 1999

Front end AC to DC converters of the boost type are used in traction applications for generating the DC link for the inverters. A GTO based converter is usually switched with a switching frequency of 300 to 500Hz, resulting in low frequency harmonic problems. In order to avoid this, multiple converters with phase shifted carrier signals are used to suppress the low frequency harmonics. A detailed study of an AC to DC converter, parallel operated with reduced sensor and improved power-factor in light load conditions is presented in this paper.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.

• 전력전자학회논문지
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• 제25권4호
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• pp.319-328
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• 2020

The recent use of distributed power generation systems constructed with DC-DC converters has become extremely popular owing to the rising need for environment friendly energy generation power systems. In this study, a new single-phase five-level inverter for off-grid applications constructed with a multilevel DC-DC step-up converter is proposed to boost a low-level DC voltage (36 V-64 V) to a high-level DC bus (380 V) and invert and connect them with a single-phase 230 V rms AC load. Compared with other traditional multilevel inverters, the proposed five-level inverter has a reduced number of switching devices, can generate high-quality power with lower THD values, and has balanced voltage stress for DC capacitors. Moreover, the proposed topology does not require multiple DC sources. Finally, the performance of the proposed topology is presented through the simulation and experimental results of a 400 W hardware prototype.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.116-118
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• 2005

In this paper, a three phase PWM noninverting Buck-Boost AC-AC converter for WCF applications is presented. The PWM noninverting Buck-Boost AC-AC converter is modelled by using vector DQ transformation whereby the basic DC characteristics equation is analytically obtained. Finally, the PSIM simulation shows the validity of the modelling and analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.119-121
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• 2005

In this paper, a three phase PWM Watkins-Johnson AC-AC converter for VVCF applications is presented. The PWM Watkins-Johnson AC-AC converter is modelled by using vector DQ transformation whereby the basic DC characteristics equation is analytically obtained. Finally, the PSIM simulation shows the validity of the modelling and analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.122-124
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• 2005

In this paper, a three phase PWM Zeta AC-AC converter for VVCF applications is presented. The PWM Zeta AC-AC converter is modelled by using vector DQ transformation whereby the basic DC characteristics equation is analytically obtained. Finally, the PSIM simulation shows the validity of the modelling and analysis.

• Journal of Power Electronics
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• 제4권3호
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• pp.169-179
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• 2004

This paper presents the steady-state analysis of the three-phase self-excited induction generator (SEIG). The three-phase SEIG with a squirrel cage rotor is driven by a variable-speed prime mover (VSPM) or a constant-speed prime mover (CSPM) such as a wind turbine or a micro gas turbine. Furthermore, a PI closed-loop feedback voltage regulation scheme of the three-phase SEIG driven by a VSPM on the basis of the static VAR compensator (SVC) is designed and evaluated for the stand-alone AC and DC power applications. The simulation and experimental results prove the practical effectiveness of the additional SVC with the PI controller-based feedback loop in terms of its fast responses and high performances

• Journal of Power Electronics
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• 제7권2호
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• pp.124-131
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• 2007

In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM resonant DC-DC converter with two simple auxiliary commutation lossless inductor snubbers is presented. The operation principle of this converter is described using the switching mode equivalent circuits. This newly developed multi resonant DC-DC converter can regulate its DC output AC power under a principle of constant frequency edge-resonant soft switching commutation by an asymmetrical PWM duty cycle control scheme. The high frequency power regulation and actual power characteristics of the proposed soft switching PWM resonant DC-DC converter are evaluated and discussed. The operating performances of the newly proposed soft switching inverter are represented based on simulation results from an applications point of view.

• Journal of Power Electronics
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• 제12권2호
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• pp.276-284
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• 2012

AC/AC power conversion is widely used to feed AC loads with a variable voltage and/or a variable frequency from a constant voltage constant frequency power grid or to connect critical loads to an unreliable power supply while delivering a very balanced and accurate sinusoidal voltage system of constant amplitude and frequency. The load specifications will clearly impose the requirements for the inverter stage of the power converter, while wider ranges of choices are available for the rectifier. This paper investigates the utilization of a buck-type current source rectifier as the active front-end stage of an AC/AC converter for applications that require an adjustable DC-link voltage as well as elimination of the low-frequency common mode voltage. The proposed solution is to utilize a combination of two or more zero current vectors in the Space Vector Modulation (SVM) technique for Current Sources Rectifiers (CSR).

• KEPCO Journal on Electric Power and Energy
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• 제3권1호
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• pp.17-21
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• 2017

Recently, the Korea Enhanced Power system Simulator (KEPS) was upgraded with new processor cards and various peripheral devices. The purpose of the upgrade is for the large-scale AC/DC simulation studies for different purposes such as FACTS, PMU applications, and SPS. The need for such study is now growing in KEPCO network. Frequently, traditional ways of performing the necessary study had been found to be less adequate for guiding the key decisions in the company. Therefore, the growing needs, as well as the revealed inadequacy of the traditional system studies, had been attributing to the momentum for the upgrade project. This paper explains the details of the upgrade project. As an example of presenting the effectiveness of the upgraded RTDS system in KEPRI-KEPCO, a large-scale AC/DC real time simulation case which includes the entire Korean network and a planned MMC-HVDC system is introduced.