Rate-limiter control comparison for energy storage systems in aerospace applications

DC bus power quality and rate-of-change in electrical generator power are compared for different energy storage system (ESS) rate-limit controller designs. The rate-limit feature enables the electrical generator(s) on a MEA to be protected from sudden load transients, which is anticipated to reduce their maintenance requirements and extend lifetime. The rate-limit is achieved using four different methods; adaptive method, low-pass filter, finite state machine and fuzzy logic. The controllers are compared using an ideal (generic) ESS simulation model, and an experimentally validated supercapacitor-based ESS model. The low-pass filter, fuzzy logic and adaptive supervisory control methods all successfully minimise the transients on the generator over the full range; if the generator is vulnerable to sudden load transitions over a limited load range then the adaptive method can prioritise this load range and better protect the generator.