Impact of PWM Voltage Waveforms on Magnet Wire Insulation Partial Discharge in SiC-Based Motor Drives
Impact of PWM Voltage Waveforms on Magnet Wire Insulation Partial Discharge in SiC-Based Motor Drives
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DOI：
10.1109/access.2021.3129266
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
M. Diab;Wenzhi Zhou;C. Emersic;Xibo Yuan;I. Cotton
中科院分区：
文献类型：
--
作者：
M. Diab;Wenzhi Zhou;C. Emersic;Xibo Yuan;I. Cotton
局部放电（PD）是逆变器供电电机绕组绝缘过早失效的主要原因。随着快速开关宽带隙碳化硅（SiC）功率半导体器件的出现，随机绕线电机由于高频陡前沿开关转换导致电机端子处的过电压振荡和电机绕组匝内的非均匀电压分布而更容易受到高度重复PD的影响。本文研究了两电平、三电平和准三电平PWM波形对逆变器供电的硅基电机局部放电行为的影响。针对不同的PWM电压波形，分析了绝缘缺陷（空气腔）内的电场分布，以从理论上预测基波周期内可能发生的PD事件的数量和相位。实验性局放测量装置用于验证理论分析，方法是将基于SiC的功率转换器产生的PWM电压波形应用于由双绞线漆包电磁线创建的典型匝间电机绕组绝缘系统。当电力电缆用于仿真电缆馈电电机驱动中的电压反射时，生成相位分辨的PD模式以评估每个电压波形的PWM特性和相关过压模式的PD行为。文中给出了详细的实验说明，包括局部放电测量方法和数据后处理算法。所得到的结果进行评估，并得出结论，作为一个有用的和及时的参考，提高绝缘PD过程中的SiC基电力电子应用的理解。
Partial discharge (PD) is a prime cause of premature failure of inverter-fed motor winding insulation. With the emergence of fast-switching wide-bandgap silicon-carbide (SiC) power semiconductor devices, random-wound motors are more vulnerable to highly repetitive PDs due to the high-frequency steep-fronted switching transitions that result in overvoltage oscillations at the motor terminals and non-uniform voltage distribution within the motor winding turns. This article investigates the impact of the applied PWM voltage waveforms on the PD behavior in SiC-based inverter-fed motors, including two-level, three-level, and quasi-three-level PWM waveforms. The electric field distribution inside insulation defects (air cavities) is analysed for the different PWM voltage waveforms to theoretically predict the number and phase of probable PD events within the fundamental cycle. An experimental PD measurement setup is used to validate the theoretical analysis by applying the PWM voltage waveforms, that are generated by SiC-based power converters, on a typical turn-to-turn motor winding insulation system created by a twisted pair of enamelled magnet wire. Phase-resolved PD patterns are generated to assess the PD behavior against the PWM characteristics of each voltage waveform and the associated overvoltage pattern when power cables are used to emulate the voltage reflections in cable-fed motor drives. Detailed experiment specifications are provided in this article involving PD measurement methods and PD data post-processing algorithms. The obtained results are assessed, and conclusions are drawn as a useful and timely reference that enhances the understanding of insulation PD process in SiC-based power electronics applications.