Research On Two Quasi-Δ-Source Inverters

Nowadays,countries around the world have studied distributed generation technologies such as solar photovoltaic power generation and wind power generation for a long time.However,part of the power generated by distributed power is direct current,which must pass through the inverter to the AC load.Therefore,the development of distributed generation technology has also promoted the continuous development and improvement of inverter performance.The initial structure of the inverter was complicated,and a special booster circuit was required in the front end.Later,Z-source inverter and quasi-Z-source inverter with good performance were proposed.In recent years,inverters with coupled inductor structures have also been proposed and developed rapidly,such as Y-source inverter and Δ-source inverter,which have become one of the inverters with the best performance.In this thesis,by studying the topological structure and the working performance of quasi-Z-source inverter and Δ-source inverter,aiming at the problems of large start-up inrush current,discontinuous input current and large capacitor voltage stress in the A-source inverter,two quasi-Δ-source inverter topologies are proposed based on the A-source inverter topology.Firstly,the working principle of Δ-source and two quasi-Δ-source inverters are analyzed,and the boosting capabilities,capacitor voltage stress,input current,start-up inrush current and leakage inductance of the three topologies are compared and analyzed.Secondly,small signal modeling of two new topologies is performed to verify the stability of the system and the impact of passive components on the stability of the system,and select component parameters based on the stability analysis results.Thirdly,the SPWM and SVPWM control strategies and their implementation methods are studied,and SPWM is selected as the control method in this experiment.Finally,software simulation analysis and hardware experiment are performed to verify the correctness and practicability of the two new topologies,they also have good dynamic stability.The software simulation and hardware experiment of the two new topologies have verified their respective advantages.Compared with Δ-source inverter,type Ⅰ quasi-Δ-source inverter has the advantages of strong boosting capability,continuous input current,and small start-up inrush current,type Ⅱ quasi-Δ-source inverter has the advantages of strong boosting capability and low capacitor voltage stress.