Virtual synchronous control of brushless doubly-fed induction generator

This paper attempts to provide inertia contribution of wind turbines in the access to weak grid with low short-circuit ratio. To this end, a virtual synchronous control (VSC) was presented for brushless doubly-fed induction generator (BDFIG) based on the popular phase-locked loop synchronizing technique. The VSC-BDFIG can synchronise with the grid directly through active power control and differs from other VSC controls in the imitation of the operation features and inner potential-control winding current relation of synchronous generator. Then, an electromechanical motion equation was established to describe the inertial dynamics of VSC-BDFIG wind turbines. Thanks to the imitation of the operation features of synchronous generator, the BDFIG naturally provides the desired inertial response like synchronous generator. Later, the frequency response features of a single wind turbine were simulated at different controller parameters and operation conditions. The results verify the superiority of the VSC-BDFIG on inertial support capability and operation stability over the typical phase-locked loop-based vector control, especially for weak grid access. The research findings shed new light on the application of the BDFIG in wind power systems. © 2018 Lavoisier