Reduction of hydrogen transfer by constrained control of anode hydrogen recirculation in a polymer electrolyte membrane fuel cell

Leakage of hydrogen due to formation of pinholes endangers the membrane longevity in a polymer electrolyte membrane fuel cell (PEMFC). In this work, based upon a novel approach, mitigation of the hydrogen transfer leak rate is achieved via controlling the speed of the hydrogen recirculation blower (HRB) as well as fuel overpressure control. The problem is formulated as a constrained control problem. Considering the multivariable nature of the control problem, a model predictive controller is employed to meet with the objectives. Moreover, the control limitation in presence of large transfer leaks is discussed. In order to evaluate the controller performance, an experimental model of a Ballard 3kW test station equipped with an HRB is utilized, where the model is derived on the basis of pneumatic modeling technique with inclusion of the hydrogen transfer leak model. Simulation results demonstrate the controller's ability for reducing the leak rate while handling the constraints, which leads to an improved durability for the membrane. Furthermore, it confirms the controller limitation.