Adaptive Control of the Hybrid Power System in Fuel Cell City Bus

Abstract

For hybrid power system composed of a fuel cell engine and a group of Ni-H batteries, a new control method with a bi-directional power converter is proposed. On the base of analyzing the output characteristic of the fuel cell engine, an external characteristic of the bi-directional power converter is designed, making the Ni-H batteries automatically adjust their charging or discharging currents. As a result, the output power of the hybrid system is controlled adaptively, obtaining stable outputs of I-t and U-t processes of the power system.