Partial Discharge Detection of Electrical Machine Insulation Under PWM Voltage with High dv/dt for More Electric Aircraft

The electrical machines for More Electric Aircraft (MEA) are driven by wide-bandgap (WBG) semiconductor devices with high dv/dt (tens-hundreds of V/ns) under extreme environmental conditions (low pressure and high temperature). Partial discharge (PD) detection is one of the most important methods to ensure insulation reliability. However, the electromagnetic interference (EMI) caused by the pulse voltage with high dv/dt interferes with the conventional measurement of PD. This paper introduces a down-mixing method based on UHF and a photoelectric method with silicon photomultiplier tube (SiPM) to detect PD of electrical machine insulation. These two methods are highly immune to EMI and they are used to measure the repetitive partial discharge inception voltage (RPDIV) of twisted pairs under pulse voltages with high dv/dt at low air pressures and high temperatures.