实现风电场低电压穿越的MMC型动态电压调节器

摘要

针对传统风电场在逐台机组的低电压穿越（LVRT）改造中存在机组数量大、塔筒空间受限等问题，提出一种基于模块化多电平变流器（MMC）的新型动态电压调节器（DVR）拓扑，串联接入风电场公共连接点（PCC），电网电压跌落时，通过输入补偿电压的方式维持PCC电压，从而辅助风电场集中实现LVRT。给出了相应控制方法和调制策略，并利用PSCAD／EMTDC建立了风电场和集中式LVRT-DVR的仿真模型。仿真结果验证了该拓扑及相应控制策略的正确性和有效性。%In view of the problems such as big generator amount and limited tower space existing during the traditional wind farm low voltage ride-through (LVRT) update reform, a new dynamic voltage restorer (DVR) topology based on modular multilevel converters (MMC) is proposed which can improve LVRT capability of wind farms by injecting a complementary voltage at the point of common coupling (PCC) while the grid voltage sags. Related control strategies and the modulating method are also proposed. PSCAD/EMTDC simulations are carried out to prove the, correctness and effectiveness of the proposed topology and the related control strategy.