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Voltage Equalizing of Solar Modules for Shadowing Compensation

  • Jou, Hurng-Liahng (Department of Electrical Engineering, National Kaohsiung University of Applied Sciences) ;
  • Wu, Kuen-Der (Department of Electrical Engineering, National Kaohsiung University of Applied Sciences) ;
  • Wu, Jinn-Chang (Department of Microelectronics Engineering, National Kaohsiung Marine University) ;
  • Chung, Cheng-Huan (Department of Electrical Engineering, National Kaohsiung University of Applied Sciences) ;
  • Huang, Ding-Feng (Department of Electrical Engineering, National Kaohsiung University of Applied Sciences)
  • Received : 2016.05.14
  • Accepted : 2017.01.25
  • Published : 2017.03.20

Abstract

This paper proposes a shadowing compensation method for the solar modules of grid-connected photovoltaic generation systems. The shadowing compensator (SC) implemented by the proposed shadowing compensation method is used only for the solar modules that can be shaded by predictable sources of shading. The proposed SC can simplify both the power circuit and the control circuit as well as improve power efficiency and utilizes a voltage equalizer configured by a modified multi-winding fly-back converter. The proposed SC harvests energy from the entire solar cell array to compensate for the shaded sub-modules of the solar cell array, producing near-identical voltages of all shaded and un-shaded sub-modules in the solar cell array. This setup prevents the formation of multiple peaks in the P-V curve under shaded conditions. Hardware prototypes are developed for the SCs implemented by the conventional and modified multi-winding fly-back converters, and their performance is verified through testing. The experimental results show that both SCs can overcome the multiple peaks in the P-V curve. The proposed SC is superior to the SC implemented by the conventional multi-winding fly-back converter.

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