Low-Harmonics Three-Phase Power Conditioner for Photovoltaic Integration

Abstract: This paper describes the design of a power conditioning unit (PCU) for photovoltaic power system to be interconnected with the utility grid (UG). The proposed PCU employs six-pulse three-phase inverter with modified-sinusoidal-pulse- width-modulation (MSPWM) switching technique, a parallel and series filters and an efficient control of dc to ac power conversion. The parallel and series filters are de-signed for both harmonics reduction and power factor correction. The efficient control of dc to ac power conversion makes the inverter output voltage immune to the variation in the dc voltage. The proposed PCU has been studied with both equation solving and extensive simulations. A 5 MW PCU has been designed and its performance has been investigated in detail