Research on photovoltaic inverter based on improved Z-source network

In order to solve the problems of the traditional Z-source inverter’s weak boosting ability and large inductor ripple current, an improved Z-source inverter topology is proposed. The improved Z-source network is composed of a combination of a high-gain boost unit and a symmetrical quasi-Z-source inverter. Compared with a switched inductor quasi-Z source inverter, it has a higher boost capacity and lower capacitor voltage stress under the same duty cycle. Based on the simple boost modulation strategy, the grid-connected design of the improved Z-source inverter is carried out. The modeling and simulation were completed in Matlab/Simulink, and the correctness of the improved Z source topology in the grid-connected system was verified. The improved Z-source inverter can be better adapted to the development needs of high-gain converter low-voltage input occasions.