A Rotor Current Balancing Control Strategy for DFIG-VSG under Weak Grid Unbalance Conditions

This paper takes the rotor current balance under the unbalanced power grid as the control objective. Based on not changing the characteristics of the voltage source of the DFIG-VSG (Doubly Fed Induction Generator with Virtual Synchronous Generator characteristics), an adaptive rotor current balance control strategy applicable to the grid-forming DFIG is proposed. The virtual synchronous control structure is improved to achieve the stability of the grid angular frequency output by the DFIG-VSG under the unbalanced grid voltage. This strategy can suppress the rotor current imbalance when the grid frequency fluctuates, and it has practical engineering significance.