Repeat and PI Control Five level Photovoltaic Grid-connected Inverter

Introducing a kind of bidirectional switch type five level inverter, and put forward the compound control scheme which repetitive control and PI adjustment are combined. Five-level inverter can reduce the waveform distortion rate of the output voltage waveform. Repetitive control can suppress the periodic perturbation which from the network and load of grid-connected output current, reducing its total harmonic distortion coefficient. PI adjustment of the inverter output grid-connected current real-time tracking reference sine given signal, so that the system has excellent static and dynamic characteristics, to improve the inverter control precision. The results show that, the five-level inverter which using repetitive PI control, the output voltage waveform distortion rate is low, its output grid-connected current waveform stability, harmonic distortion rate is small, and can real-time tracking the network voltage.