Energy management of power-split plug-in hybrid electric vehicles based on simulated annealing and Pontryagin's minimum principle

• Use quadratic equations to calculate fuel rate as a function of battery current.
• Use SA and PMP to determine engine-on power and battery current.
• Fuel economy is improved, as validated by simulation.
• Battery state of health is introduced to extend the application.

In this paper, an energy management method is proposed for a power-split plug-in hybrid electric vehicle (PHEV). Through analyzing the PHEV powertrain, a series of quadratic equations are employed to approximate the vehicle's fuel-rate, using battery current as the input. Pontryagin's Minimum Principle (PMP) is introduced to find the battery current commands by solving the Hamiltonian function. Simulated Annealing (SA) algorithm is applied to calculate the engine-on power and the maximum current coefficient. Moreover, the battery state of health (SOH) is introduced to extend the application of the proposed algorithm. Simulation results verified that the proposed algorithm can reduce fuel-consumption compared to charge-depleting (CD) and charge-sustaining (CS) mode.