Voltage tracking and regulation of vehicle PEMFC system under low load condition based on fuzzy LQG hybrid strategy.

In automotive fuel cell systems, high-voltage operation accelerates carbon support and platinum catalyst degradation, significantly compromising system durability. This study develops a dynamic system model with active cathode recirculation to capture the transient response of voltage, and proposes a hybrid control scheme that combines a proportional compensator with a fuzzy LQG controller to effectively enhance voltage regulation and disturbance tracking capabilities. Extensive simulation and hardware-in-the-loop (HiL) confirm the precision and rapid response of the developed controller. Compared to single LQG and fuzzy LQG controllers, the error reduction achieved is 49.3 % and 40.3 %, respectively, and the overall control benefit ratio improves by 19.2 % and 11 %. This method balances dynamic response with control efforts, effectively reducing the risk of high voltage-induced degradation under low-load conditions.