方波脉冲电压下聚酰亚胺薄膜老化特征研究

Study on ageing characteristics of polyimide film under pulse voltages

针对脉宽调制(PWM)技术在电力机车变频调速应用中,导致电机绝缘在连续脉冲电压下过早老化的问题,对变频电机绝缘主要材料聚酰亚胺薄膜进行方波脉冲电压下的电老化试验。通过对不同老化阶段聚酰亚胺薄膜tanδ的测量,从介质损耗规律方面对材料在脉冲电压下老化特征进行研究。结果表明,在不同的老化阶段,介质损耗随电压、频率的变化趋势保持一致,介质损耗随老化时间的增加而变大;老化使聚酰亚胺薄膜的起始放电电压降低,介质损耗随电压增加而增大的趋势更加明显;聚酰亚胺薄膜的介质损耗在高频区的激增点会随着老化时间的增加而向高频区移动。

When the PWM technology was used to modulate the speed of electric mobiles with changing frequency, the insulating material of the electric motor would age faster. Accelerated aging test was condueted on polyimide film, the popular insulating material for electric motors, with continuous pulse voltages. The aging features of pulse voltages were characterized with the relationships between tanδ vs. voltage, frequency at different aging stages. The results show that in different stage, dielectrie loss changes in a consistent trend with voltage and frequency and increases with the aging time, aging lower the start discharge voltage and the increasing trend of dielectric loss becomes more evident, the proliferate point in the high-frequency region of the dielectric loss will move to the higher frequency with the aging time increasing.