Mitigating power systems variability in more electric aircraft utilizing power electronics implemented dynamic thermal storage

Increased power levels in more electric aircraft (MEA) bring opportunities to optimize energy flow in multi-physics domains to benefit the power system's stability and aircraft fuel economy. This paper introduces thermal energy inherent in the cabin air and aircraft fuel as a dynamic management solution to offset stochastic load power in the MEA power system. Focus is on power electronic controlled environmental control system (ECS) drives, which can provide dynamic thermal inertia and act as an effective electric swing bus to mitigate power variability. The generator's output power becomes substantially more constant as a result, decreasing the demand from fast generator responses or dedicated energy storage such as batteries. In practice, the motor drives operate on a suitable bandwidth in the sense of filtering unwanted frequencies in the stochastic energy band. The lower update frequency limits air temperature variations in the cabin, and the higher update frequency, combined with ramp-rate and acoustic limits, lets the ECS to respond without generating annoying noise. A high-level implementation builds upon a feedforward control loop. A more sensitive virtual synchronous machine concept added to the loop boosts desirable inertia in the MEA power system. The combination is illustrated in simulation and with experimental results based on realistic load power demand over a mission profile using Boeing 787 as a platform.