Design and Implementation of a High-Frequency Bipolar Square-Wave Pulse Generator With Full Duty Cycle Control and Nanosecond-Rise Time

To study the partial discharge (PD) of packaging materials for high-voltage silicon carbide devices under conditions of high d$v$/d$t$and wide duty cycle, a nanosecond-level high-repetition-rate, full-duty-cycle bipolar square-wave pulse power supply suitable for the research on packaging insulation properties was designed and developed. This power supply forms a bipolar square-wave output through the cascading of multilevel submodules combined with a symmetric positive–negative voltage division structure, and adopts a folded output loop to significantly reduce parasitic inductance. Experimental results show that when the maximum output peak-to-peak value is 10 kV and the repetition frequency reaches 45 kHz, the rise time of the square-wave pulse can be stably maintained at approximately 18 ns, the fall time is about 23 ns, and the duty cycle can be flexibly adjusted within the range of 0%–100%. Based on strict mathematical derivation, the coupling relationship between dead time, repetition frequency, and duty cycle is clarified, and the driving and power supply schemes are optimized accordingly. Compared with existing test power supplies, this system has achieved significant breakthroughs in fast rising edge, high repetition frequency, and full-duty-cycle control, providing a reliable experimental basis for in-depth revelation of the failure mechanism of packaging insulation materials in silicon carbide high-voltage power modules.