Performance Improvement of a Grid-connected Direct Drive Wind Turbine Based on STATCOM with Super-capacitor Energy Storage

In this paper, the control and operation strategy of grid-connected direct drive variable speed wind turbine based on permanent magnet synchronous generator (PMSG) is studied by applying a static synchronous compensator (STATCOM) with super-capacitor. The control strategies for generator-side converter with maximum power extraction, grid-side inverter and STATCOM controller are implemented in Matlab/Simpower, and such extensive simulations as STATCOM +/ system by using different super-capacitor energy storage to enhance the steady state and dynamic performances of the wind energy system under grid faults or disturbances are conducted. By comparing with traditional STATCOM, simulation results show that the application of STATCOM with super-capacitor can effectively improve voltage flicker and volatility and reduce frequency fluctuation during grid connecting, then effectively control the current during fault occurs, which obviously improve active and reactive power of direct drive wind generation system, the fault ride through capability and dynamic performance of grid-connected wind power system.