变流器开路故障下永磁直驱风电系统运行分析

变流器是永磁直驱风电系统中故障率最高的器件,文中针对变流器故障后系统运行特性的变化,在变流器数学模型的基础上,深入分析变流器中一个开关管发生开路故障后的工作情况。研究表明:一个开关管发生开路故障后系统可持续运行,但会影响该变流器的正常工作,引起对应侧电流波形畸变。在MATLAB/Simulink环境下建立永磁直驱风电系统模型,并搭建永磁直驱风力发电实验平台,分别在3种不同的开路故障下进行仿真和实验,围绕机侧和网侧电流、直流母线电压、有功输出比例、总谐波畸变率,评估故障对系统运行特性的影响。根据仿真和实验结果得出变流器开路故障特征:一个变流器的开路故障对另一侧的正常运行影响较小,但故障器件对应侧的相电流出现波形畸变。

Operational Analysis of D-PMSG Based Wind Power Generation System Under Open-circuit Converter Faults

The failure rate of converters is higher than any other components in the directly driven permanent magnet synchronous generator (D PMSG) based wind power generation systems. Contraposing the changes of the system operating characteristics after converter fault, this paper presents a in depth study on the operating conditions of converter after an open circuit fault based on the mathematical model of converters. The studies show that the system is still sustainable after an open circuit fault of a switch tube, but the operation condition of the converter will be affected and the current waves of the corresponding side will distort. The model of D PMSG based wind power generation system is developed using MATLAB/Simulink, and the experiment platform for the D PMSG based wind power generation is given as well. Simulations and experiments are performed under three different types of open circuit faults. The effects of faults on the system operation characteristics are investigated by the calculation and analysis of some key parameters, such as generator side current, grid side current, DC bus voltage, active power output ratio, and total harmonic distortion. The simulation and experimental results show that an open circuit fault in one converter has little effects on the normal operation of the converter at the other side, but waves of the phase currents at the corresponding side of fault components will distort.