Modeling and control of an air supply system for a heavy duty PEMFC engine

Air supply system is one important subsystems in a PEMFC engine system. Research on modeling of centrifugal air compressor for easy and accurate control and control strategy of air supply system based on the centrifugal air compressor model are of great importance and significance in engineering. Based on the working characteristics of the centrifugal air compressor in our 150 kW PEMFC engine system for a hybrid tram, a semi-mechanical semi-imperial air supply system model was established. Then the model was embedded in the fuel cell control system for dynamic control of the centrifugal air compressor following the duty cycle of the engine, and a compound feed-forward PID control method for the air system was proposed. Experimental and simulation results show that the air system model performs quite good celerity and accuracy. The compound feed-forward PID control method is able to make full use of the fast response characteristic of centrifugal air compressor, with dynamic response time greatly shortened, and the steady control accuracy requirements achieved. The model and the control method proposed in this paper could be used to optimize the control of the air supply system and to better the dynamic performance of electric vehicle powered by PEMFC engine.