PWM脉冲电压下电磁线绝缘老化机理分析

随着电力电子技术的发展，脉宽调制(PWM)电源得到了广泛应用。由于该电源输出电压是一系列脉冲电压，有可能导致变频电机绝缘过早破坏。目前，有关高压连续脉冲电压下绝缘材料失效机理各方观点尚未达成一致；过去的研究大多停留在宏观水平，主要是定性的实验研究，缺少微观定量分析的支持。针对上述问题，本文对变频电机定子绝缘的电磁线进行了老化实验。在此基础上，通过热刺激电流和脉冲下局部放电参数的关系，揭示了老化时间和陷阱参数(如峰值位置、陷阱能级)的联系。同时测量了局部放电参数(如起始放电电压、最大放电量、放电相位分布)随老化时间的变化。上述工作的开展，为更深入的脉冲电压下绝缘老化机理研究打下了坚实的基础。

Study on Insulation Aging Properties of Magnet Wire Under PWM Voltages

It has been observed that voltage waveforms generated by power electronic converters may affect significantly the reliability of electric motor insulation.The electrical characterization of magnet wire for electric motor has been investigated through aging tests under different aging time.The space charge parameters(e.g.,the amount of charge,trap energy level)in magnet wire under pulse width modulated(PWM)voltages were investigated by thermally stimulated current(TSC)to understand the relationship between trap parameter and aging time.In addition,partial discharge parameters(e.g.,inception voltage,repetition frequency,phase distribution of discharge number)have been measured.In particular,relationship between aging time and the parameters of the TSC curve are observed in the specimen.Relationship between PD parameters and space charge accumulation has also been observed.These phenomena,if confirmed,could be used to develop new materials for PWM voltage applications.