A hybrid LVRT control scheme for PMSG wind power system

Abstract

Low voltage ride through (LVRT) is one of the most important issues of wind power system. This paper proposes a mechanical and electrical hybrid method of LVRT control for permanent magnet synchronous generator (PMSG), in which the stabilization of the DC-bus voltage and the maximum power point tracking (MPPT) are realized by controlling of motor-side voltage source converter (VSC) and grid-side VSC respectively. When voltage dip occurs, the rotating speed of the rotor would be firstly increased and store the redundant energy. In case the rotor speed reaches its mechanical limitation, the braking resistor would secondly consume the exceeding energy. With the proposed scheme, the PMSG can smoothly achieve LVRT and greatly reduce energy dissipation. Simulation results validate the superiority of the proposed strategy.