一种PMSG低电压穿越综合控制策略

Integrated Control Strategy for a Kind of Low Voltage Ride Through of PMSG

分析了关于直驱风电机组的不同低电压穿越方法的优缺点,结合直驱风电机组结构特点,提出一种能适应于不同电压跌落情况下的低电压穿越综合策略,即减少发电机出力,将变阻值卸荷电路和桨距角控制相结合,以避免直流电容过电压和发电机超速为原则,确保发电机和变流器的安全运行;网侧逆变器提供无功支持,同时采用基于磁控电抗器(Magnetically Controlled Reactor,MCR)的动态无功补偿装置进行无功补偿。在PSCAD平台上构建基于综合控制策略的直驱永磁风电机组模型,通过仿真验证了不同电压跌落下的直驱永磁风电机组低电压穿越能力,以及综合控制策略的可行性。研究表明低电压穿越综合策略能兼顾提升机组低电压穿越能力和故障穿越结束后风电机组的稳定运行能力。

In this paper, the advantages and disadvantages of different low voltage ride through methods for the direct drive wind turbine are studied. A kind of integrated strategy of low voltage ride through which is suitable for different voltage sag is proposed with combination of structure feature of the direct drive wind turbine, that is to reduce the output of generator, to combine unloading circuit of the variable resistance with control of the pitch angle and, on the principle of avoiding overvoltage of DC capacitor and over speed of generator, assure safe operation of the generator and converter. The reactive power support is provided by the side converter and, at the same time, reactive power compensation is made by the use of dynamic reactive power compensation device which is based on the magnetically controlled reactor （ MCR in short ）. The model of direct drive permanent magnet wind turbine generator based on integrated control strategy is constructed on the PSCAD platform. The low voltage ride through ability of the direct drive permanent magnet wind turbine generator at different voltage sag and feasibility of the integrated control strategy are verified by the simulation. It is shown by the study that the integrated strategy of low voltage ride through can improve the low voltage ride through ability of generator and stable operation ability of wind turbine generator after the fault ride through.