Energy management and control of a fuel cell/supercapacitor multi-source system for electric vehicles

This article presents a control strategy of a multi-source system dedicated to automotive applications, aiming to maximize the global system efficiency. A parallel-architecture of the multi-source system is considered, composed of a fuel cell as a primary power source, a supercapacitor as a secondary storage element, which provides peak power in fast transients, and power converters for the power sources interconnection to the DC bus. The power management is realized as a two-level control structure. The first level contains inner control loops for fuel cell/supercapacitor currents and a DC bus voltage control loop, designed using PI controllers. The higher level consists of an energy management supervision system based on the equivalent consumption minimization strategy. The fuel cell power demand is computed by minimizing the hydrogen mass consumption with respect to system physical constraints. The performances of the proposed control structure are evaluated in simulation, in terms of fuel economy, using an urban driving cycle.