Development of a Nanosecond-Level High-Voltage Bipolar Square Wave Generator for Insulation Testing of SiC Device Packaging

Aiming at the insulation testing requirements for high-voltage silicon carbide (SiC) device packaging under bipolar square wave voltage conditions, this article proposes and develops a novel nanosecond-level high-voltage bipolar square wave generator based on cascaded half-bridge submodules. Under a typical capacitive load, the generator achieves a peak-to-peak voltage of 10kV, an adjustable repetition frequency from dc to 50kHz, and a duty cycle ranging from 0% to 100%, with a rise time compressed to approximately 39ns. By combining a series-isolated power supply design with common-mode filtering, the proposed approach significantly reduces common-mode interference under high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv</i>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> conditions, ensuring high-voltage isolation of the driver stage and improves electromagnetic compatibility. Compared with traditional pulse topologies such as Blumlein lines, linear transformer drivers (LTDs), and Marx generators, the proposed generator excels in flat-top waveform quality, flexible pulsewidth/duty-cycle modulation, and nanosecond-level rising edges. It thus provides a more precise and reliable experimental platform for investigating partial discharge and insulation-aging mechanisms in high-voltage SiC devices.