Combined Use of a Resistive SFCL and DC-link Regulation of a SMES for FRT Enhancement of a DFIG Wind Turbine Under Different Faults

Abstract

To strengthen the fault ride-through support for a doubly-fed induction generator (DFIG)-based wind turbine, this paper studies the combined use of a resistive superconducting fault current limiter (SFCL) and a superconducting magnetic energy storage (SMES). The installation sites of the SFCL and SMES are the DFIG's stator and dc-link, respectively. The SFCL offers the expectations of current-limitation and terminal-voltage compensation, and the SMES brings the functions of controlling dc-link voltage and absorbing unbalanced power. The theoretical modeling, control method and influence mechanism are studied, and the simulations of symmetrical and asymmetrical faults are done in MATLAB. From the results, the contributions by the combined SFCL and SMES include: First, the overcurrents in the stator and rotor of the DFIG are quickly suppressed. Second, the variations in the DFIG terminal voltage and dc-link voltage are well reduced. Third, the unbalanced power and electromagnetic torque fluctuations of the DFIG are availably mitigated. Finally, a preliminary capacity optimization considering multiple energy features is discussed to further promote the proposed approach.