Real-time power optimization for an air-coolant proton exchange membrane fuel cell based on active temperature control

Abstract

Air-coolant proton exchange membrane fuel cells (PEMFCs) have the characteristics of compact structure and low cost, benefiting for lightweight applications such as aircrafts with limited volume. However, the air-coolant PEMFC has strong coupling between air supply and cooling resulting in difficultly analyzing the relationship between optimal power and stack temperature to cause low power efficiency. To effectively increase the output power of the air-coolant PEMFC under changeable environmental conditions, this article introduces a real-time power optimization strategy based on the active temperature control. To output the continuously maximum power, an improved temperature perturb and observe (P&O) is designed to obtain an optimal temperature reference. Considering the PEMFC is a highly nonlinear system, the super-twisting algorithm (STA)-based controller is developed to regulate the stack temperature. After the optimal temperature is determined, the STA controller may lead to the target temperature be well tracked with strong robustness under unknown external disturbances. To validate the proposed strategy, practical experiments were carried out in a 1-kW air-coolant PEMFC under different operation scenarios, and the results showed that the power was increased over 4% when the air-coolant PEMFC operated under relatively high load. Overall, the proposed strategy looks promising for power optimization of air-coolant PEMFCs.