Research on Synchronous Frequency Oscillation Mechanism of Photovoltaic Virtual Inverter Under the Coupling of Machine Network

The virtual synchronous generator is a new inverter control method that has emerged in recent years. The program draws on the working principle of the power frequency controller and the excitation controller to make the inverter a virtual synchronous generator set, thus having a more uniform and compatible inverter control interface. However, due to the synchronous frequency resonance phenomenon of the virtual synchronous generator, it is easy to cause power oscillation and cause system instability. In order to solve the above problems, based on the system analysis of the dynamic process of virtual synchronous photovoltaic inverter, based on the generation mechanism of synchronous frequency resonance, an active damping control strategy is proposed to suppress the resonance problem. Simulation shows the effectiveness of the strategy.