Research on WindVar VSCF-DFIG

Most wind power plant operators and utilities have employed capacitors to correct power factor during operation, and also, some wind projects have fixed static VAR compensators or other similar equipments to achieve the goal. Unfortunately, these methods are expensive and complex and cannot provide an optimal solution. In this paper, the field-oriented vector control technique and the auto-disturbance rejection controller (ADRC) were transplanted into the active and reactive power decoupling control technique of the doubly-fed induction generator. And a novel WindVar control strategy was obtained, through which voltage is controlled and regulated in real-time. The WindVar system supplies reactive power to the grid at the time when it is needed, regulating system voltage and stabilizing weak grids. Similar to conventional utility generators, the addition of a wind project equipped with WindVAR electronics can actually strengthen the weak grid. This system also has the potential to provide emergency backup support and support to weak grids in need of transmission and distribution. WindVAR system enables the wind turbines to operate at unity, leading or lagging power factor (unity power factor shown above), providing the highest transmission efficiencies and enhanced voltage stability. All these are verified by simulation and experiment.