Investigations on Partial Discharges Risk in Aeronautical Rotating Machine Fed by HVDC 540VDC Network

The voltage level aboard new aircraft generations has grown from 115VAC to 230VAC. This has given rise to a new HVDC +/- 270V instead of +270V. The Adjustable Speed Drives (ASD) aboard more electrical aircraft are currently fed by fast switching PWM IGBT converters which rise time and fall time are greater than 50ns. To improve the converters power density, the very fast Wide Bandgap semiconductor technologies (Silicon Carbide) are currently under evaluation; their switching rise time and fall time could be less than 20ns. This paper, by using industrial ASD fed by 540Vdc, initially addresses an experimental investigations analysis of motor overvoltages according to: inverters technologies (IGBT and SiC), harness length and harness shielding. Then, investigations on the Partial Discharges Inception Voltage (PDIV) are carried out on primary components of Electrical Insulation System (EIS) type 1 at atmospheric and reduced pressures, according to several parameters: magnet wire (MW) diameter, MW grade, polyimide insulating paper thickness. The paper concludes with a discussion of the different results and thoughts about overvoltages and partial discharges challenges.