A Distributed Maximum Power Point Tracking Flyback Type PV Grid-connected Inverter

Aiming at the power loss caused by photovoltaic (PV) mismatch problem, a distributed maximum power point tracking (DMPPT) Flyback type PV grid-connected inverter and the sinusoidal pulse width modulation(SPWM) unified control strategy with DMPPT are proposed. Meanwhile, the circuit topology, operation modes and steady state relations are deeply investigated. The inverter is composed of n Buck choppers with their outputs connected in series and a Flyback type grid-connected inverter, it belongs to quasi-single-stage power conversion. The control strategy achieves the DMPPT of all PV cells and the control of grid-connected current simultaneously. Designed and implemented 500W 27-39VDC/220V50HzAC prototype has excellent performances such as high PV cell utilization efficiency, low cost, high conversion efficiency, high reliability, high quality of output waveforms, etc.