A Two-Stage Optimization Scheme of Fuel Consumption and Drivability for Plug-In HEVs

This paper addresses an energy consumption optimization problem with consideration of drivability improvement for series-parallel plug-in hybrid electric vehicles. Consumption of fuel and electricity are chosen as the cost function of the optimization, and the acceleration rate is involved in the constraint for improving drivability. Then, a two-stage optimization scheme is proposed, which consists of the long-term off-line optimization and the short-term on-line optimization. In the former, the entire route is dealt with as previously known, and the optimal mode switching and engine power are provided by solving the optimization problem, and in the latter, the short-term local optimization in the fashion of receding horizon is used to obtain optimality regarding the actual route situation where the vehicle-to-everything-based driver's demand prediction is involved instead of requiring previous information of the future horizon. The proposed controller was evaluated in the case of a long driving situation including the city and the motorway that required a high-power acceleration. The performance was improved in consideration of the drivability, and the fuel economy was optimized in comparison to the charge depleting and charge sustaining strategy