Real-time Control for a Parallel Hybrid Electric Vehicle Based on Pontryagin's Minimum Principle

A heavy-duty parallel hybrid electric vehicle (HEV) is modeled first, together with dynamic equations of subsystem components. The HEV energy management problem was cast into an optimal control problem since its objective is to minimize fuel consumption while maintaining the state-of-charge of the battery within reasonable bouds. The Pontryagin's Minimum Principle (PMP)-based optimal algorithm is applied to solve the optimal control problem. A causal optimal strategy with a simple proportional-integral (PI)-control based on PMP is put forward, which can realize real-time control for HEV. The solutions of the causal optimal strategy are found to be very close to the global optimal solutions when tuning with the appropriate co-states.