直驱风机低电压穿越控制技术研究及实测验证

随着风电大规模接入电网,新的并网规范要求风力发电机组必须具有低电压穿越能力.针对直驱式风电机组,采用直流母线卸荷电阻限制电压跌落时变流器直流环节产生的过电压,并通过改进电流控制策略抑制变流器过电流,从而实现永磁同步发电机风电机组的低电压穿越运行.在网侧变流器数学模型的基础上进行了卸荷电阻的优化设计,提出了电网电压跌落故障时网侧变流器的改进电流控制策略,最后在1.5 MW级永磁同步发电机风电机组上进行现场低电压穿越能力测试,实测验证了所提出方法的正确性.

Research and Verification of LVRT Control Techniques for Direct-Drive Wind Turbines

With large-scale wind power integration in the power grid,the new grid codes for wind power integration require the wind turbines to have the capability of low voltage ride through （LVRT）.For direct-drive wind turbine units,the DC bus chopper resistance is applied to limit the over-voltage in the current transformer when voltage falls,and an improved current control strategy is adopted to restrain the over-current.In this way,the LVRT operation of a permanent magnet synchronous generator （PMSG） is achieved.In this paper,the design of the chopper resistance is optimized based on the mathematic model of the grid side converter （GSC） and an improved current control strategy is proposed to regulate the over current of the GSC under grid voltage drop.In the end,the LVRT capability is tested on a 1.5 MW permanent magnet synchronous generator wind turbine to validate the correctness of the proposed design techniques.