Implementation Method of Grid-connected Inverters Based on Virtual Asynchronous Machine and Reactive Compound Control

An implementation method of grid-connected inverters based on virtual asynchronous machine is presented, the voltage and current characteristics of the grid-connected inverters are equivalent to the actual asynchronous machine and its load by simulating its electromagnetic and mechanical transient model. Under the power control mode, the generating torque threshold is set to make it work in the feedback braking mode, and the active power is injected into the grid. The grid voltage can be operated at the unit power factor through the cooperation of the reactive compound control, and when the active power changes, there is no reactive power exchange between the grid and the system. Step-by-step starting by the simulation of the series resistance on the rotor can effectively reduce the grid-connected current, which improve the reliability and security of grid connection without phase-locked loops and pre-synchronization. Simulation results verify the feasibility and effectiveness of the presented scheme.