Research on Demagnetization Technology for Virtual Synchronous Control of Doubly-Fed Wind Turbines

Virtual synchronous generator (VSG) control method, a mainstream grid-forming (GFM) control strategy, is a research hotspot in the field of wind generation currently because it enables wind generators to provide inertia, damping, frequency and voltage support to the grid. The sensitivity of the doubly-fed induction generator (DFIG) to grid voltage fluctuations and the slow dynamic characteristics of the VSG control method make VSG-based DFIG prone to induce overcurrent in the rotor windings when faced with grid voltage drops, threatening the safe operation of the converter. In this paper, a new control strategy is applied to solve the overcurrent problem of DFIG based on current-loop-containing VSG control during transients, which accelerates the decay rate of the stator magnetic flux during transient periods and speeds up the output power oscillation process of DFIG during the fault. The simulation results verifies that the control strategy has a superior demagnetization control effect.