Research Of Single Phase Grid-Connected Inverter Based On Quasi-PR Controller

With the development of new energy power generation technology, a large number of distributed generations(DG) be connected to power grid, grid-connected inverter is the main connection device between DG and power grid, When DG are connected to power grid, the output current should have the same frequency and phase with grid voltage, to decrease pollution of the grid, so, it is very important to research the technology of grid-connected current.In this paper, quasi-Proportional resonant(quasi-PR) controller is studied, quasi-PR control can overcome the disadvantages of proportional-integral(PI) and Proportional Resonant(PR) controller, what PI controller cannot ensure the output to track the sine wave signal and PR controller cannot effectively control the fluctuation of power grid. Firstly, This paper simply discuss a grid-connected inverter system, and present a detailed introduction on inverter topology, output filters and current control strategy, A mathematical model of single-phase grid-connected inverter using average state space method is studied, analyzes the advantages and disadvantages of PI、PR and quasi-PR controller, three types of controller have been studied from controller characteristic, steady state error and interference immunity, the superiorities of quasi-PR controller have been testified. This paper introduced the design method of single-phase inverter including hardware design, software design and detailed analyzes the influence of quasi-PR controller parameters on performance of controller, a design methods of controller parameters is introduced.Finally, the simulation waveform based on PI、PR and quasi-PR controller was presented and verified the effectiveness of theory analysis. A single-phase inverter system based on quasi-PR controller was constructed and experimental waveform are presented.