An optimal regulation strategy for energy management of hybrid electric vehicles

The issue of designing an analytical optimal solution to the problem of energy management for charge-sustaining hybrid electric vehicles is addressed. In particular, it is shown that, by suitably casting the energy management problem into a nonlinear optimal regulation problem and using an appropriate control Lyapunov function candidate, it can be proved that the state-feedback based optimal control law (with respect to minimum fuel consumption) produces a charge-sustaining behavior. We provide sufficient conditions for state feedback based control law to guarantee asymptotic stability and optimality with respect to an infinite horizon performance functional. The optimal control law is implemented in a series hybrid electric vehicle and the performance of the proposed energy management strategy is shown in simulation for a specific driving case.