Innovative design and decoupling control of an efficient, simplified MFCS air supply system for renewable hydrogen-powered stacks

Multi-stack fuel cell systems (MFCS) are widely utilized in high-power demand applications such as distributed renewable energy power generation system due to the stability. However, these systems face challenges including complex structures and significant parameter coupling. To address these challenges, this paper proposes an efficient and simplified integrated air supply structure, which utilizing the air compressor to regulate buffer pressure and the backpressure valve to control mass flow rate, simplifying system structure and reducing air compressor power consumption by up to 43 % to improve net power. Based on this structure, this paper presents an internal model controller (IMC) that significantly reduces the settling time and decreases the mass flow overshoot by 62.6 % compared to traditional proportional-integral control methods under the mass flow rate step response for fuel cell stacks, while also reducing pressure fluctuations by 20 %. To address coupling in MFCS, a Partial Feedforward Decoupling IMC (PFD-IMC) is proposed. Compared to Full Feedforward Decoupling IMC (FFD-IMC), PFD-IMC uses a simplifier structure while achieving similar decoupling performance. It eliminates overshoot in mass flow rate step responses and reduces pressure fluctuations by 69.4 %. PFD-IMC shows superior performance in handling pressure step responses, single flow variations, and dynamic operations, significantly improving system efficiency.