Study on the impact of space charge on the lifetime of pulsed capacitors.

As a key influence factor on the lifetime of pulsed capacitors, the repetitive frequency (fR) of charge/discharge is studied in this paper based on the method of TSDC measurement. When fR ranges from 0.1 Hz to 10 Hz, the lifetime of capacitors increases. The TSDC measurement is conducted, which is used to study the parameters of space charge induced by charge/discharge at various frequencies. The measurement result indicates that compared with capacitors which have experienced no charge/discharge, for capacitors that have experienced charge/discharge at 0.1, 1, 8 and 10 Hz for 3000 times, the trap density within the dielectric respectively increases by 66.1, 62.1, 54.8 and 31.5%. For pulsed capacitors which have experienced charge/discharge at 10 Hz, the peak current (IM) is 22.2 pA, meanwhile, for pulsed capacitors which have experienced charge/discharge at 0.1 Hz, the Im is 29.4 pA. For pulsed capacitors which have experienced charge/discharge at 10 Hz, the depth of deep traps is 0.94 eV, and the temperature corresponding to Im is 97 °C, meanwhile, for pulsed capacitors which have experienced charge/discharge at 0.1 Hz, the depth of deep traps is 1.83 eV, and the temperature corresponding to Im is 110°C. The parameters reflecting the characteristic of space charge can reasonably explain why the lifetime of capacitors tested at 10 Hz is three times of that at 0.1 Hz. [ABSTRACT FROM PUBLISHER]