重复方波下气压对新能源汽车主绝缘材料电老化特性影响研究

Effect of air pressure on electrical ageing characteristics of new energy vehicle main insulation materials under repeated square waves

为探究高海拔环境对新能源汽车驱动电机主绝缘材料电老化性能的影响,选取NHN绝缘纸作为主要研究对象,根据新能源汽车实际工况,对其施加双极性重复方波,测量其在不同气压下的局部放电起始电压(PDIV);采用标准大气压下的PDIV值作为标准电压,在不同气压下对试样施加1.5倍标准电压,测定电老化30 min以及老化至击穿两种情况下试样的物理与电气参数,并检测电老化过程中生成的臭氧含量。结果表明:低气压下主绝缘试样的PDIV值显著降低,并且相对于平原地区,当施加电压大于PDIV时,其表面受腐蚀情况更严重,导致其更容易击穿;在相同时间与电压的电老化过程中,低气压试样的电气参数变化更大,局部放电生成臭氧的速率更快,对材料腐蚀加剧,绝缘性能的劣化更严重。综合以上研究,在设计新能源汽车电机绝缘系统时,应充分考虑海拔因素对绝缘材料耐电晕性能的影响。

To investigate influence of high-altitude environment on the electrical ageing performance of the main insulating material of new energy vehicle(NEV)drive motor,NHN insulating paper was selected as the main research object.According to the actual working conditions of NEV,the NHN insulating paper was applied bipolar repeated square waves,and its partial discharge inception voltage(PDIV)under different air pressures was measured.The PDIV value under standard atmospheric pressure was used as standard voltage,and 1.5 times of standard voltage was applied to the samples under different air pressures.The physical and electrical parameters of the samples under the condition of electrical ageing for 30 minutes and ageing to breakdown were measured,and the ozone content generated during the electrical ageing process was detected.The results show that the PDIV value of the main insulation sample decreases significantly under low pressure,and when the applied voltage is greater than the PDIV,the sample surface is corroded more severely compared with the plain area,leading to the sample break down easier.During the electrical ageing process with the same time and voltage,the electrical parameters of the samples under low pressure have bigger change,the ozone production rate of partial discharge is faster,the corrosion of the material is intensified,and the deterioration of insulating properties is more serious.Based on above studies,the influence of altitude factors on the corona resistance performance of insulating materials should be fully considered when designing the insulation system of motor for NEV.