Gain-scheduled LQR control of an aerospace drive system with LC filter and long feeder cable

The aviation industry is moving towards more electric aircraft. This involves replacing conventional pneumatic, mechanical, and hydraulic systems with electrical alternatives for increased efficiency and reduced maintenance. This paper addresses the current controller design of an electrical aerospace drive systems with a centralised topology, whereby the power electronics is connected to the machine via a long feeder cable. Switched voltages with high dv/dt applied to long cables whose surge impedance matches poorly with that of the load can lead to high amplitude, high frequency voltage oscillations due to transmission line effects. An LC output filter is required to mitigate the transmission line effects. The inclusion of an LC filter can lead to uncontrolled voltage resonance. Thus, a full state feedback gain-scheduled LQR controller is utilised. To minimise the number of additional sensors, an observer is utilised. Simulation results with an inverter switching model and distributed transmission line model are shown.