A Novel Low Voltage Ride-Through Scheme for Dfig Based on the Cooperation of Hybrid Energy Storage System and Crowbar Circuit

Abstract

To improve the low voltage ride-through (LVRT) capability of DFIG, a novel LVRT scheme based on the cooperation of hybrid energy storage system (HESS) and crowbar circuit is proposed. The HESS composed of superconducting magnetic energy storage (SMES) and batteries is connected in DC-link bus of DFIG. During grid faults, the grid side converter (GSC) of DFIG is controlled to inject reactive power to the grid, while the HESS stabilizes the DC-link bus voltage of DFIG and the crowbar circuit is activated in real-time according to the rotor current. During normal operation, the GSC is controlled to manage the output power of the DFIG with HESS, and the HESS is utilized to deal with power difference between the turbine generation power and power dispatching command. The simulations of the DFIG with HESS system is conducted in RTDS platform, and the simulation results show that the proposed scheme can effectively achieve the LVRT of DFIG during gird faults and flexibly manage the output power of the DFIG with HESS during normal operation.

Keywords: Double-fed induction generator (DFIG)Hybrid energy storage system (HESS)Low voltage ride-through (LVRT)Crowbar circuitOutput power managementSuperconducting magnetic energy storage (SMES)