Design of Partial-discharge-free Busbar for More-electric Aircraft Application with Low Pressure Condition

This paper proposes an insulation design and optimization methodology for laminated busbars in more-electric aircraft (MEA) motor drive system. The design assumes that the converter works at around 11-km altitude with decompressed air pressure, which expedites partial discharge (PD) compared to it at sea-level. The trade-off between the insulation margin and power-loop stray inductance is revealed and optimized. By using the method, a busbar for a 450-kVA 3-level T-type neutral-point-clamped (3L-TNPC) converter is designed. Its partial discharge inception voltage (PDIV) is 43% higher than the rated voltage at the air pressure of 0.2 atm and 170% higher at normal air pressure. Busbar stray inductance of 12.0 nH is achieved, lower than published literature of 3-level converters.