Research On Control Strategy Of The Grid Inverter With Harmonic Voltage

With the booming development of the new energy industry, the green energy such as wind power and solar energy is increasing important in power system. Grid connected inverter is key part of energy conversion of the distributed generation like wind power generation, photovoltaic power generation. It can turn wind power and solar energy into electrical energy and connect grid, which will greatly improve the utilization of renewable energy. But now, because a large number of nonlinear devices are connected to the distributed generation system, harmonic current flowed into the system. These harmonics greatly affect the quality of power grid, and also impact heavily on the safe and stable operation of the power grid. It is necessary to suppress the harmonic current and power fluctuation in the system. This paper is on the basis of L -type grid inverter and the control strategies of grid inverter are studied under the harmonic voltage.The control system demands greater performance of the controller which is different from the traditional controller under the background of harmonic voltage. The grid inverter is modeled under grid harmonic voltage and the paper analyzes the mathematical model, which afford a necessary theoretical support for harmonic suppression. The performance of multi-PI controller, quasi PR controller and quasi PIR controller are studied and the system composed by them is analyzed in impedance. The matlab/simulink simulation circuit is set, and the control effect of different regulators is verified in the experiment platform from both the theory and practice. Due to involving interconnection problems and the grid distortion, so the obtain of grid angle need to be studied. The paper mainly analyzes the DSOGI-FLL and the MSOGI-FLL with good extraction of harmonic voltage and angle.