Virtual Synchronous Control Strategy for Doubly-Fed Induction Generator under Asymmetrical Grid Faults

Much attention has been paid to Virtual Synchronous Control (VSynC) strategy for Doubly-Fed Induction Generator (DFIG) due to its advantage in providing dynamic supports of frequency and voltage. However, current researches of VSynC strategy focus on analysis of its electromechanical behaviors, and neglect its electromagnetic transient responses and fault characteristics, hindering its application in grid-fault situation. This paper studies the electromagnetic transient behaviors of VSynC-based DFIG and proposes a voltage compensation VSynC strategy to implement fault ride through during asymmetrical grid faults. The proposed strategy improves the inherent defect of existing VSynC strategy, capable of limiting the overcurrent in DFIG rotor circuits and suppressing the oscillations of electromagnetic torque. Simulation results validate the effectiveness of the proposed strategy.