GaN-based ±5kV/100kHz PWM Generator for Advanced Partial Discharge Characterization

With the development of wide bandgap power devices, higher voltage and higher frequency PWM voltages are applied in power electronics system. However, there is a lack of research tools on insulation system partial discharge (PD) characterization under high-frequency PWM voltage stress with high dv/dt. To address this issue, this paper designed and implemented a ±5kV GaN-based PWM generator for PD characterization. 600V GaN devices and a high-frequency transformer are utilized to lower the cost. Additionally, the intelligent PWM generator can provide controllable dv/dt at the rising and falling edges, variable duty ratio and switching frequency and controllable output voltages up to ±5kV. The developed PWM generator is utilized to test a twisted Litz wire sample and the PD signals are monitored by a high frequency current transformer (HFCT) and TEM antenna.