Design and performance of a passive EMI filter for three-stage aircraft starter/generator system

In this paper a new output electromagnetic interference (EMI) filter for the three-stage aircraft starter/generator system is designed and its performance is analyzed. For the traditional generator system, the machine is directly connected to the PWM drive system, which causes both the differential mode (DM) and common mode (CM) noises at both generator terminals and the long leads, which increases high-frequency leakage currents, bearing currents, and shaft voltage. Considering the harsh conditions on aircraft and the control strategy of a 75kW three-stage starter/generator system, a model of passive EMI filter was constructed and simulated with Matlab-Simulink to verify the effectiveness of the design method.