高压陶瓷电容器在重复频率脉冲下的性能测试及改善

Test and Improvement in Performance of High Voltage Ceramic Capacitor Under Repetitive Pulses

为研究高压陶瓷电容器在重复频率充放电过程中的性能变化情况,搭建了一台基于两级磁压缩和脉冲变压器的重复频率高压脉冲电源,并在25 Hz的频率下对高压陶瓷电容器的性能进行测试。主要研究了电容器寿命随脉冲电场强度的变化情况,电容器的失效模式,以及改善电容器性能的措施。结果表明:高压陶瓷电容器的寿命随电场强度的增加而下降;电容器在重复频率下的失效模式有陶瓷介质的内部击穿、陶瓷-环氧界面击穿和铜电极端子的脱落三类。因此,可通过增加环氧包封韧性来缓冲陶瓷-环氧界面的电-热应力,改善铜电极端子结构来减低接触面的烧蚀,从而改善高压陶瓷电容器在重频下的性能。

In order to study the performance of high voltage ceramic capacitor(HVCC)under charging and discharging at repetitive frequency,a high-voltage pulsed power source with repetitive frequency based on two-stage magnetic compression and pulse transformer was developed,and the performance of HVCC was tested under the frequency of 25 Hz.The relationship between the lifetime of HVCC and electric field,the failure modes,and methods to improve the performance of HVCC were investigated and analyzed.The results show that the lifetime of HVCC decreases as the electric field strength increases.Failure modes of HVCC include the inner breakdown of ceramic dielectric,the interface breakdown of ceramic-epoxy,and the abscission of brass terminals.Therefore,the electro-thermal stress of the ceramic-epoxy interface can be buffered by increasing the toughness of the epoxy encapsulation,and the ablation of the contact surface can be reduced by improving the structure of brass electrode.Therefore,the performance of HVCC under repetitive frequency can be improved greatly.