Research on Multi-Stage Photovoltaic Inverter Based on Microcontroller

A 1 kW multi-stage photovoltaic inverter power supply was researched.The first stage uses Buck circuit to achieve MPPT;the middle push-pull circuit uses SG35725 to control.When the traditional single voltage controlled inverter power supply works in nonlinear loads,the output waveform has a large serious harmonic distortion.Based on it,a capacitor voltage and capacitor current double closed loop control strategy was proposed,using microcontroller to realize the digital PI control.The correctness of the analysis was verified by experiment.