Grid-connected topology of PMSG wind power system based on VSC-HVDC

As the wind power generation technique is improved greatly, permanent magnet synchronous generator (PMSG) is paid more and more attention because of its multiple advantages. Nevertheless, conventional directly-drive PMSG wind generation system is connected to the grid by AC transmission. This paper introduces the DC connection structure of wind farm based on PMSG. According to VSC-HVDC (Voltage Source Converter based HVDC) transmission, the topology of series-parallel DC generation units is proposed. Regarding to the control strategy of the power generation and transmission system mentioned above, the DC voltage is controlled on generator-side for achieving the purpose of seriesparallel, and on grid-side active and reactive power decoupling method is applied to track maximum wind power by controlling the d-axis and q-axis current of the grid. The models of singlegenerator, series connection and parallel connection system are established on the PSCAD/EMTDC platform. Simulation results prove the validity of the topology scheme and the corresponding control strategy.