Photovoltaic Single-Phase Grid-Connected Inverter Based on Voltage and Reactive Power Support

In this paper, a kind of PV grid-connected inverter suitable for low voltage ride through is proposed. In order to alleviate the voltage drop at the power grid access point during the fault, the photovoltaic inverter needs to provide a certain amount of reactive power support to the power grid. The orthogonal quantities in the time domain are transformed into direct quantities by the dq rotating orthogonal coordinate system, so that decoupling control of active power and reactive power can be achieved. In order to achieve the smooth switching of the working mode, the parameter design of the PID controller needs to be analyzed according to the controlled object model. The simulation results show that the photovoltaic grid-connected inverter under the decoupling control can realize the reactive power support to the voltage drop at the grid-connected point in time.