Airflow and Power-Split Control Strategy for a Fuel Cell Hybrid Powered Robot

Abstract

Fuel cell control systems are designed to regulate temperature and reactant flow rates to ensure efficient electrochemical reactions and to avoid degradation and membrane failure from stack overheating. In air-cooled systems, the temperature is controlled by regulating the cathode airflow. In this study, a pseudo-spectral optimization method is applied to obtain an optimal power-split while considering the fuel cell’s thermal dynamics to avoid stack overheating and minimize the hydrogen consumption for a hybrid electric vehicle. For future real-time implementation, a dual-loop proportional plus integral (PI) control strategy is proposed to regulate the airflow by following a fuel cell temperature reference, while another PI controller regulates the fuel cell current by tracking a reference battery State Of Charge (SOC). The proposed PI controller which follows a fixed temperature setpoint and a linearly depleting battery state of charge trajectory, based on the average power consummation and trip duration, can achieve 96% of the fuel savings of the optimum hydrogen consumption with full preview information.