DFIG Protection with Rotor-Side SMES and Negative Sequence Control under Voltage Unbalance

To minimum the capacity of rotor-side SMES and reduce the cost, the capacity ratio between energy storage converter (ESC) and RSC are redesigned. Dual control strategy is utilized into ESC controller to eliminated the influence of negative sequence component of rotor current during voltage unbalance. Two kinds of control target are analyzed in detail and the control diagram in ESC has been designed. Simulation has been done to validate the effectiveness of proposed method. Simulation results express that the controller can precisely carry out the two control targets.