变流器开路故障下永磁直驱风电系统运行分析

摘要

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。%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. This work is supported by International Science & Technology Cooperation Program of China(No.201 1DFA62240).