Control strategies for low voltage ride-through of a direct-driven wind turbine unit with a permanent magnet synchronous generator

Based on the analysis of the low voltage operation characteristics of a direct-driven wind turbine unit with a permanent magnet synchronous generator(DDPMSG)under power grid faults,an integrated control strategy for improving the low voltage ride-through capability of a DDPMSG and the stability of power grid connected was proposed,which included maximum power tracking by pinch angle control; generator electromagnetic-power limiting to control the power transferred to the DC-link and grid-side converter and stable DC-link voltage controlling by limiting the grid-side converter current with generator-side power output.The model of a DDPMSG and the proposed control strategy were simulated by using PSCAD/EMTDC software.The simulation results show the validity and feasibility of the proposed control strategy.