• 전기학회논문지
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• 제60권3호
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• pp.538-543
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• 2011

In this paper, design and control of an interleaved boost converter for multi-string PV Inverter are discussed. Interleaved Boost converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. One of the advantages of the multi-string system is easy to expand power capacity by connecting the converter modules in parallel. In order to reduce current ripples, the inductor currents on each phase are controlled independently in the converter module, and communication between the converter modules is required for further ripple current reduction. Current control algorithm for the balance of the each phase ripple currents and synchronization of the converter modules based on communication are proposed and implemented in the DSP programming. 10kW prototype of the multi-string converter module is assembled and experimental results are presented to verify the proposed ripple current reduction methods.

• 한국산업융합학회 논문집
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• 제21권2호
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• pp.71-78
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• 2018

In this paper, we propose the performance enhancement of solar individual string power generation system using booster power control for voltage compensation. The proposed control method determines the variable voltage for the compensator using direct power control (DPC) modeling applied to motion factor estimation. This method also maintains excellent dynamic response to the characteristics of direct power control (DPC) by calculating the mismatch ratio of the arrestered PV modules. The validity of the proposed algorithm is verified through simulation and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.154-157
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• 2008

In korea, PV business has been growing fast since 2000. There are many ways to build PV module Among them, BIPV system(BIPV : building integrated system) using PV modules as external wall has been carried out research on and invested much. I suggest another way to apply the BIPV system BIPV SU(string unit) module is easier and faster to be installed and more economical than other BIPV module. In this paper. I will show how to make, and how to install this BIPV SU module.

• 전기학회논문지
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• 제64권7호
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• pp.1012-1018
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• 2015

The studies on the operating performance analysis or design about the fixed tilt angle flat-plate photovoltaic (PV) system are still lively going off. However the operating property analysis about the arch type PV system which means PV array were designed as round type is dissatisfied. In this paper, we theoretically established the factors which are cause of the deterioration in performance of arch type PV system. In addition, we use the Solar Pro simulation tools to design both flat-plate type and arch type 30kW PV systems. The simulations about arch type PV system applied two ways such as central inverter and string inverter were conducted. The performance ratio (PR) of the PV system with flat-plate type shows the highest value 74[%] when the tilt angle is 30°. In case of arch type, when applying central inverter method, PR value shows approximately 73[%] and no more difference with arch type of the PV array. This value shows 1[%] decrease compare with the flat-plate type. However when applying string inverter methods, the average PR value shows 80 % and 6% improved than the central inverter method.

• Current Photovoltaic Research
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• 제7권2호
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• pp.51-54
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• 2019

The high density module (HDM) has advantages for its larger active area and smaller current density. This new way of making a photovoltaic (PV) module method has benefit for increasing module power with the same installed area. Because HDM consisted with serially connected PV strings, loss of strings during the fabrication process can increase the overall production cost.1-2 This study investigates the rework conditions of the shingled strings with electrically conductive adhesives (ECA). By heating the electrically connected area of a fabricated string, cured area become soft and a string can be detached for the rework process. After rework process, a refabricated string showed 5~10% increased output power compared to before rework process and reached to the 90~95% output power compare to the undamaged strings.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.241-241
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• 2007

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.123-125
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• 2009

Mismatch of electrical characteristics of modules in PV string invokes mismatch power loss. The mismatch occurs due to various causes such as shadow, aging, contamination, and module exchange. The concept of mismatch compensation converter(MCC) is presented in this paper to remedy the mismatch loss problem. MCC is connected to irregular modules only. MCC is composed of dc-dc converter and MPPT controller. It is noted that MPPT algorithm is employed to control MCC and is effective for maximum power available from irregular modules. The selection guide of MPPT control period is given based on the period of MPPT in PCU. The effectiveness of the MCC is verified by a prototype experiment.

• Journal of Power Electronics
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• 제13권2호
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• pp.296-303
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• 2013

This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.170-171
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• 2010

The power loss due to PV module mismatch in PV array system is analyzed and a mismatch compensation method is proposed. A dc-dc converter is used to compensate for series mismatch caused by a low current module in a string. The converter is controlled to maximize the array power output. The proposed compensation method was verified by PSpice simulation.

• Journal of Power Electronics
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• 제19권4호
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• pp.1011-1019
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• 2019

In this paper, a buck-flyback (fly-buck) stand-alone photovoltaic (PV) system for charge balancing with a differential power processor (DPP) circuit is proposed. Conventional feed-back DPP converters draw differential feed-back power from the output of a string converter. Therefore, the power is always through the switches and diodes of the string converter. Because of the returning conduction path, there are always power losses due to the resistance of the switch and the forward voltage of the diode. Meanwhile, the proposed feed-back DPP converter draws power from the magnetically-coupled inductor in a string converter. This shortens the power path of the DPP converter, which reduces the power losses. In addition, the extra winding in the magnetically-coupled inductor works as a charge balancer for battery-stacked stand-alone PV systems. The proposed system, which uses a single magnetically-coupled inductor, can control each of the PV modules independently to track the maximum power point. Thus, it can overcome the power loss due to the power path. It can also achieve charge balancing for each of the battery modules. The proposed topology is analyzed and verified using 120W hardware experiments.