Thermal Management for the Cabin of a Battery Electric Vehicle Considering Passengers’ Comfort

Abstract

Due to the absence of an internal combustion engine and the corresponding waste heat, battery electric vehicles have a significantly reduced range in cold environments. Moreover, also at high ambient temperatures, the energy consumption of the air-conditioning system has a negative effect on the range. In this paper, a thermal management strategy for the passenger compartment of a battery electric vehicle is developed with the aim to reduce the power consumption of the heating, ventilation, and air-conditioning (HVAC) system. Simultaneously, the thermal comfort of the passengers has to be ensured. To address both objectives, a predictive, optimization-based approach for the thermal management system is developed. Models for the vehicle cabin and the HVAC system are derived and identified using measurement data. These models are used to formulate an optimal control problem, where also system limitations are considered explicitly. To avoid the computationally expensive solution of a nonlinear optimal control problem, it is approximated by a linear-quadratic model predictive control problem. This can be solved very efficiently and is suitable for real-time implementation on an automotive control unit. The proposed linear-quadratic strategy is compared with a baseline strategy and the nonlinear strategy to show the effectiveness of the proposed approach.