基于多相PMSG和三电平变流器的风电机组低电压穿越

当前国内外对于风电机组的并网规范都要求电网发生电压跌落时风电机组能够保持不脱网运行以帮助电网故障恢复。针对一种新型的基于多相直驱永磁同步发电机(PMSG)和混合式三电平变流器的大功率直驱风电系统的低电压穿越技术进行了研究。首先分析了电网故障对直驱风电系统带来的影响,然后给出了新型机组的低电压穿越策略,即通过改变电机侧和电网侧变流器的电流给定,配合发电机转速调节的方法来控制系统的能量传输,进而达到穿越故障的目的。最后建立了所提出的风电系统的时域模型,给出了不同电网故障情况下的仿真结果,验证了控制策略的可行性和有效性。

Low Voltage Ride Through Control of Large Direct-drive Wind Turbine with Multiphase PMSG and Hybrid Three-level Full-size Converters

In the case of grid voltages dips,the wind power plants are demanded to keep connected to the grid,and to help the network recover from the fault.This paper focuses on the low voltage ride through(LVRT) control of large-scale wind energy system based usinga multiphase direct drive permanent magnet synchrony generator(PMSG) and three-level converters.The paper analyzes the impact of generator side rectifiers and grid side converters cased by symmetrical or asymmetrical voltage dip.In order to fulfill the LVRT requirement,the energy accumulated in the converters has to be reduced.A control approach is developed,which is implemented by resetting current command and adjusting the speed of PMSG.Finally,a time-domain computer simulation is done for the proposed system.Simulation results confirm the feasibility and validity of the proposed method.