Fuel cell systems emerge as a new technology, which is expected to play an important role for future powertrain applications. To enable this technology's entrance into the market, new developments to improve robustness, cost efficiency and maintainability are necessary. Besides the stack itself, several subsystems are required to operate a fuel cell system. The technical challenges for developing and optimizing these subsystems are comparable to the challenges in the stack development itself. The air delivery system is considered to have a major impact, subject to overall efficiency, noise emissions and costs. These properties are determined not only by the system hardware, but also by the chosen control strategy.
This paper describes an intelligent model based control strategy, which enables the system to use optimal operation points of compressor and motor. The quantities to be controlled are air mass flow and pressure. The precise achievement of the desired values is crucial for proper stack functionality and stack lifetime. The controlled parameters are the compressor speed/torque and the opening of the return manifold pressure valve. The paper considers all aspects of the controller development and the implementation of such a system including controller hardware and hardware-in-the-loop simulation.
The results presented in this paper were achieved in simulations and on a real system.