重复脉冲占空比对变频电机匝间绝缘耐电晕寿命影响研究

Effect of Duty Cycle of Repetitive Impulsive Voltage on Corona-resistant Lifetime of Turn-to-turn Insulation for Inverter-fed Motors

为研究重复脉冲占空比对变频电机匝间绝缘耐电晕寿命的影响规律,搭建了占空比可调的重复脉冲耐电晕寿命测试系统。采用Ⅰ型变频电机匝间绝缘漆包线单点接触试样,在频率为10 kHz、占空比不同的双极性重复脉冲下进行耐电晕寿命测试。结果表明:耐电晕寿命随占空比的增加而缩短,50%占空比下的耐电晕寿命比5%占空比下的短20%。在占空比低于50%时,脉冲上升沿与下降沿的局部放电分布特性不对称。因此,在根据相关标准对变频电机匝间绝缘进行耐电晕寿命评估时,为缩短实验周期和减小测试结果的分散性,建议采用占空比为50%的双极性对称重复脉冲电压。

In order to study the influence of duty cycle of repetitive impulse voltage on the corona-resistant lifetime of the turn-to-turn insulation for inverter-fed motors,a corona-resistant lifetime test system under repetitive impulse voltage with adjustable duty cycle was built.The corona-resistant lifetime of single-point contact enameled wire for type I inverter-fed motors was tested under bipolar repetitive pulse with different duty cycle at 10 kHz.The results show that the corona-resistant lifetime decreases with the increase of duty cycle,and the corona-resistant lifetime at 50%of duty cycle is 20%shorter than that at 5%of duty cycle.When the duty cycle is lower than 50%,the partial discharge distribution characteristics at rising edge and falling edge of impulse are asymmetric.Therefore,when the corona-resistant lifetime of turn-to-turn insulation for inverter-fed motors is evaluated according to the relevant standards,it is recommended to use a bipolar symmetric repetitive pulse voltage with 50%of duty cycle to reduce the experimental period and the dispersion of test results.