Energy Management System for a FCHV based on Linear Programming

Challenges facing fuel cell hybrid vehicles is in implementing a control strategy to find the optimal split of power between the different power sources. This paper proposes a mathematical model of power flow in such vehicles taking into consideration power train losses. Linear programming locates the global optimum indicating the finest synchronization among power units in an attempt to lower operational cost and reduce hydrogen fuel consumption of the energy management system for respective driving cycles. The formulation considers the life-cycle cost, limits and ramp rates of the subsystem, hydrogen tank capacity and battery state of charge. Comparison is done between the proposed controller and a controller using rule based techniques. Results indicate a reduction in system cost and up to 29% reduction in hydrogen fuel consumption highlighting the importance of using such controllers in urban driving cycles since reduction in hydrogen consumption is much higher compared to highway cycles.