冲击电流作用下氧化锌压敏电阻极性效应分析

为了能够精确测量MOV（氧化锌压敏电阻）的静态参数，利用HAEFELY PSURGE 30.2冲击波形模块在8/20 μs冲击电流下分别对MOV样品进行正负极性冲击，测量冲击后MOV的静态参数并描绘出压敏电压的变化曲线以及小电流区的伏安特性曲线。根据MOV内部双肖特基势垒模型，结合离子迁移理论，提出了MOV在冲击电流作用后同样存在极性效应，并且在负向测量时伏安特性曲线蜕变较严重；在正负极性交替冲击下，极性效应逐渐消失，但伏安特性曲线同样存在蜕变；在不同极性冲击下的压敏电压呈先上升后下降的趋势。这为今后精确地表征MOV蜕变程度提供了新的方法。

Research on polarity effect of MOV under impact current

To accurately measure the static parameters of MOV (ZnO varistor), the positive and negative impulse tests were conducted respectively on a MOV by using an 8/20μs impulse current, which was generated by the impulse generator (HAEFELY PSURGE 30.2). After the tests, the static parameters of the MOV was measured, and the voltage variation curve and the V I characteristic curve of the small current area plotted. Based on the double Schottky barrier model inside the MOV as well as the ion migration theory, there also exits polarity effect in the MOV after impulse, and significant degradation appear in the V I characteristic curve under the negative impulse. While under the alternating impulses of the positive and negative current, the polarity effect gradually disappears, but there still exits degradation in the V I characteristic curve. Under the impulses with different polarities, the voltage of the varistor firstly increases and then decreases. The study provides a new method to accurately characterize the degradation of MOV.