PMP-based power management strategy of fuel cell hybrid vehicles considering multi-objective optimization

In order to develop more practical vehicle controllers for hybrid vehicles, performance limitations of hybrid powertrain components need to be considered when constructing power management strategies. This paper introduces a Pontryagin's Minimum Principle (PMP)-based power management strategy for fuel cell hybrid vehicles which considers not only the fuel consumption minimization but also the requirement on limiting battery state of charge (SOC) usage or on prolonging fuel cell system lifetime. The battery SOC constraint problem is solved by introducing a new cost function to the PMP-based optimal control problem. The limitation requirements on the battery SOC are satisfied by this solution. In order to take into account the lifetime of a fuel cell system, another cost function is defined and added to the PMP-based optimal control problem. Simulation results show that the lifetime of the fuel cell system can be prolonged by this method. Global optimality is discussed for the two extended cases. The proposed PMP-based power management strategy saves much time compared to dynamic programming (DP) approach while it guarantees global optimality under reasonable battery assumptions.