A Novel and Practical Multi-Loop Control Strategy for Photovoltaic Inverters Based on DSP

A novel and practical multi-loop control strategy for photovoltaic (PV) inverters is presented. In which the double close-loop control structure of digital PID voltage and current instantaneous value is adopted based on the cross feedback decoupling control and load current feed-forward control. In addition, in order to improve accuracy of output voltage, a close loop control structure of the output voltage RMS value is utilized. The mathematical model for single-phase full-bridge inverters is established. The operation principle of decoupling control and the control strategy are discussed in details. A 50Hz 1kW prototype with TMS320F2812 DSP as controller is developed to validate the effectiveness of the control strategy.