DIF virtual synchronization control method and system in unbalanced power grid

The invention discloses a DIF virtual synchronization control method and system in the unbalanced power grid. The method is characterized in that a rotor-side inverter AC compensation voltage is addedon the basis of a rotor-side inverter reference voltage generated in a virtual synchronous control link, a rotor current is taken as a control object, and a resonator is utilized in a forward synchronous rotation coordinate system to control double frequency fluctuation based on different control targets. The method is advantaged in that without changing a control structure of traditional virtualsynchronous control, effective control of DIFG can be achieved under the unbalanced power grid according to different power quality requirements of the power grid, specifically, any of four control objectives of the balanced and sinusoidal rotor current, the balanced and sinusoidal stator current, the constant active power and the constant electromagnetic torque can be achieved, and each controltarget can be flexibly swit