Surge control of air compressor under variable operating pressure of automotive fuel cells

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The compressor of a proton exchange membrane fuel cell for automotive application requires severe dynamic performance under normal operating conditions. Since the air flow rate with a compressor should cover a wide range of operating conditions, it is necessary to understand the operating trajectory of the compressor. In this study, a simulation model of an automotive fuel cell system with a dynamic compressor is developed to explore the proper trajectory of the air flow rate on the performance chart of an air compressor. A dynamic simulation model of a compressor is composed of manifold dynamics of a supply and return line, static compressor model, and dynamic motor model. From the compressor to the fuel cell stack is considered as a plenum and an orifice between them is also assumed. An active control valve is also considered at the exit of fuel cell stack so that the surge can be actively rejected. The control strategy of a variable pressure compressor is concentrated on rejection of surge over various operating conditions under the load demands of driving mode.