Minimization of Hydrogen Consumption via Optimization of Power Allocation Between the Stacks of a Dual-Stack Fuel Cell System

A dual-stack fuel cell model was developed to simulate the hydrogen consumption a fuel cell-powered vehicle for a specific drive cycle. Two fuel cell stacks, each consisting of 65 parallel cells at different aging status and thus with different efficiency profiles (i.e., low and high) were considered. A constrained optimization for power distribution between individual stacks was performed where the objective function was to minimize the hydrogen consumption while meeting the total demand. For proper power management each stack has its own power controller which manipulates the stack current to control the stack power at its desired-set point. Computed optimal power values constitute the desired set-points for the local power PID controllers of the individual stacks. Closed-loop simulations were performed by simulating the developed mechanistic model together with optimization and PID controllers in SIMULINK platform. The closed loop simulations demonstrate how well the power demand of the drive cycle is tracked and the hydrogen consumption is minimized. To assess the impact of optimization strategy used, hydrogen consumption is compared to that of equal power sharing and a daisy-chain strategies. The results demonstrate that the optimization strategy effectively reduces the total hydrogen consumption.