• Journal of Power Electronics
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• v.14 no.5
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• pp.918-925
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• 2014

This study presents an extended boost single-phase qZ-source DC-AC inverter for a single-phase photovoltaic system. Unlike the previously proposed single-phase qZ-source and semi-qZ-source inverters that achieve the same output voltage as that of the traditional voltage-fed full-bridge inverter, the proposed inverter can obtain higher output than input voltage. The proposed inverter also shares a common ground between DC input voltage and AC output voltage. Thus, possible ground leakage current problem in non-isolated grid-tied inverters can be eliminated with the proposed inverter. A 120 W prototype inverter is built and tested to verify the performance of the proposed inverter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.8
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• pp.82-89
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• 2014

The industrial products to use single phase inverter are raised the necessity of power quality improvement, such as AC Motor Driver, Lighting, Renewable energy power converter. Also, it is increasing that applied the single phase multilevel inverter for high quality power at renewable energy power converter. Especially, the photovoltaic multilevel inverters have at least more than two DC_Link and more than one DC/DC Converter. This paper proposes a triple output DC/DC Converter with one switch for photovoltaic multilevel inverter. The proposed converter has advantages of low cost and volume because it has one switch. The operation principle of the converter is analyzed and verified. A prototype is implemented to verify of the proposed converter.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1233-1242
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• 2014

A new inverter topology for single-phase photovoltaic (PV) systems is proposed in this study. The proposed inverter offers a four-level voltage in its output terminals. This feature results in easier filtering in comparison with other conventional two-level or three-level inverters. In addition, the proposed four-level inverter (PFLI) has a transformer-less topology, which decreases the size, weight, and cost of the entire system and increases the overall efficiency of the system. Although the inverter is transformer-less, it produces a negligible leakage ground current (LGC), which makes this inverter suitable for PV grid-connected applications. The performance of the proposed inverter is compared with that of a four-level neutral point clamped inverter (FLNPCI). Theoretical analysis and computer simulations verify that the PFLI topology is superior to FLNPCI in terms of efficiency and suitability for use in PV transformer-less systems.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.157-168
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• 2009

In this paper, a photovoltaic system is designed with a step up chopper and single phase PWM(Pulse Width Modulation) voltage source inverter. Where proposed Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical voltage and current dropping character. The single phase PWM voltage source the inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power. from 10 to 20[%]. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In order to enhance the efficiency of photovoltaic cells, photovoltaic positioning system using sensor and microprocessor was design so that the fixed type of photovoltaic cells and photovoltaic positioning system were compared. In result, photovoltaic positioning system can improved 5% than fixed type of photovoltaic cells. In addition, I connected extra power to the system through operating the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and the phase of single-phase inverter of PWM voltage type can be synchronized. And, It controlled in order to provide stable pier to the load and the system through maintaining high lurer factor and low output power of harmonics.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1338-1348
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• 2017

In this study, a modified ripple correlation control (RCC) maximum-power point-tracking (MPPT) algorithm is proposed for a single-stage single-phase voltage source inverter (VSI) on a grid-connected photovoltaic system (GCPVS). Unlike classic RCC methods, the proposed algorithm does not require high-pass and low-pass filters or the increment of the AC component filter function in the voltage control loop. A simple arithmetic mean function is used to calculate the average value of the photovoltaic (PV) voltage, PV power, and PV voltage ripples for the MPPT of the RCC method. Furthermore, a high-accuracy and high-precision MPPT is achieved. The performance of the proposed algorithm for the single-stage single-phase VSI GCPVS is investigated through simulation and experimental results.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.238-243
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• 2003

The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuated on the variation of insolation, temperature and load. The output power of solar cell is DC, therefore it is necessary to install an inverter among electric power converts. The inverter have to supply a sinusoidal current and voltage to the load and the interactive utility line. In the paper, the proposes a photovoltaic system designed with a step up chopper and single phase PWM voltage source inverter. Synchronous signal and control signal was processed by microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical dropping character. The single phase PWM voltage source inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power, from 10 to $20\%$. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. The inverter supplies an ac power with high factor and low level of harmonics to the load and the utility power system.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.365-366
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• 2016

This paper presents a single-phase transformerless photovoltaic (PV) power converter systems based on the AC/DC boost inverter, which is capable of solving the leakage current and second-order ripple power issues. By eliminating the inherent ripple power in single-phase inverter, the bulky electrolytic capacitor can be replaced by a small film capacitor. The validity of the proposed scheme has been verified by the simulation results.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.305-311
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• 2013

This paper proposes a performance improvement of existing single-phase current-fed qZ-Source inverter. Voltage gain of the traditional voltage-fed full-bridge inverter and single-phase current-fed qZ-source inverter is only equal to or smaller than input voltage. The proposed inverter can obtain twice higher voltage gain than the single-phase current-fed qZ-Source inverter by adding an extra switch and a capacitor in the circuit. In addition, the proposed inverter shares the common ground between dc input and ac output voltage. Therefore, the proposed inverter can eliminate the possible ground leakage current problem when it is used for grid-tied photovoltaic inverter system. A 120 W prototype inverter is built and tested to verify performances of the proposed inverter.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.488-491
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• 2006

In this paper proposed method of maximum power point tracking using boost converter for a connected single phase inverter with photovoltaic system. The maximum power point tracking control is based on generated circuit control MOSFET switch of boost converter and single phase inverter uses predicted current control to control four IGBT's switch in full bridge. The predicted current control provide current with sinusoidal wave shape and inphase with voltage. The generation control circuit allows each photovoltaic module to operate independently at peak capacity, simply by detecting of the output power of the system. Furthermore, the generation control circuit attenuates low-frequency ripple voltage, which is caused by the full-bridge inverter, across the photovoltaic modules. Consequently, the output power of system is increased due to the increase in average power generated by the photovoltaic modules. The effectiveness of the proposed inverter system is confirmed experimentally and by means of simulation.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.451-462
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• 2016

Photovoltaic energy conversion becomes main focus of many researches due to its promising potential as source for future electricity and has many advantages than the other alternative energy sources like wind, solar, ocean, biomass, geothermal etc. In Photovoltaic power generation multilevel inverters play a vital role in power conversion. The three different topologies, diode-clamped (neutral-point clamped) inverter, capacitor-clamped (flying capacitor) inverter and cascaded h-bridge multilevel inverter are widely used in these multilevel inverters. Among the three topologies, cascaded h-bridge multilevel inverter is more suitable for photovoltaic applications since each pv array can act as a separate dc source for each h-bridge module. This paper presents a single phase Cascaded H-bridge five level inverter for grid-connected photovoltaic application using sinusoidal pulse width modulation technique. This inverter output voltage waveform reduces the harmonics in the generated current and the filtering effort at the input. The control strategy allows the independent control of each dc-link voltages and tracks the maximum power point of PV strings. This topology can inject to the grid sinusoidal input currents with unity power factor and achieves low harmonic distortion. A PID control algorithm is implemented in Arm Processor LPC2148. The validity of the proposed inverter is verified through simulation and is implemented in a single phase 100W prototype. The results of hardware are compared with simulation results. The proposed system offers improved performance over conventional three level inverter in terms of THD.