基于模式切换的永磁同步风力发电机组低电压穿越控制策略

随着风电机组安装容量的不断上升,风电系统在电网故障情况下的稳定运行尤为重要,电网导则要求风电机组在电网电压瞬间跌落一定范围内不脱网运行,具备低电压穿越能力(low-voltage ride-through,LVRT)。对于永磁同步风力发电机(permanent magnet synchronous generator,PMSG)机组,快速控制直流电容电压是实现低电压穿越的关键。文章采用一种基于模式切换的PMSG机组低电压穿越控制策略,该策略在电网电压正常和故障时进行控制模式切换,选择网侧变流器或机侧变流器来控制直流电容电压。另外,为加快直流母线控制速度,提出了一种改进前馈方法,加快了控制速度,降低了直流母线电压的峰值。仿真结果验证了所提控制策略的有效性。

Low Voltage Ride-through Control Strategy for PMSG Based on Control Mode Switch

With the increase of installed capacity of wind farm, the operation stability of wind power system during grid disturbances becomes important. Grid codes require that wind power system stays connected to the grid during voltage dips for a certain period, with the ability of low-voltage ride-through (LVRT). For permanent magnet synchronous generator ( PMSG) , the key to improve the ability of LVRT is that fast control DC-Link voltage when grid-voltage dips. This paper proposes a LVRT control strategy for PMSG unit based on control mode switch. The strategy changes the control mode between in normal and fault of grid-voltage, and adopts the grid-side converter or generator-side converter to control the DC-Link voltage respectively. In addition, this paper proposes an improved feed-forward method to speed up the DC bus control, which can accelerate the speed control and reduce the peak value of the DC bus voltage. The simulation results validate the effectiveness of the proposed strategy.