永磁直驱风电机组低/高电压穿越研究

Research on low/high voltage ride through of permanent magnet synchronous wind turbine

低/高电压故障穿越问题严重影响永磁直驱风电机组的安全稳定运行。为提高机组低/高电压故障穿越能力,基于常规控制方案提出改进优化策略,分别对机组常态及故障暂态过程采取多模式运行方案。机侧稳态过程实现最大功率跟踪,故障暂态时由输入输出功率差值调整转速值,改变转子转速,抑制机侧有功输入值。直流侧依据电压骤升程度,提出双模式卸荷电阻投切方案,稳定母线电压值,平稳电压波动程度。网侧提出无功补偿方案并接静态无功补偿器(STATCOM)为电网提供最大化无功支撑。通过Matlab/Simulink平台搭建仿真模型,验证所提方案的有效性与合理性。

Low/high Voltage Ride Through （L/HVRT） fault problems seriously affect the safe and stable operation of Permanent Magnet Synchronous Wind Turbine Generator （PMSG）. In order to improve the L/HVRT capability, an improved optimization strategy is proposed based on the conventional control scheme, in which the multi-mode operation control scheme is adopted for the normal and fault transient process of the wind turbine respectively, that is, the Maximum Power Point Tracking （MPPT） is realized in the steady state process of the rotor. When the fault is transient, the speed value of the input and output power difference is adjusted, the rotor speed is changed, and the active input value on the side of the machine is suppressed. Based on the degree of voltage swell on DC side, dual-mode unloading resistance switch scheme is proposed to stabilize bus voltage value and voltage fluctuation. The reactive power compensation scheme and Static Reactive Compensator （STATCOM） are put forward on the grid side to provide the maximum reactive support for the power grid. The simulation model is built through the Matlab/Simulink platform to verify the validity and rationality of the proposed scheme.