Optimal Control Allocation Strategy for an Energy-efficient PTC Heater-based Electric Vehicle Passenger Cabin Heating System

Electric vehicles (EVs) experience significant driving range degradation in low ambient temperature conditions, primarily due to the elevated energy demand of heating system. This paper proposes an optimal control strategy for a positive temperature coefficient (PTC) heater-based electric minibus heating system, which is aimed to exploit actuators’ redundancy for energy consumption minimization and driving range extension. The strategy optimally allocates control inputs of multiple actuators to provide heating power demanded by a superimposed proportional-integral (PI) feedback controller of the passenger cabin air temperature. The optimal allocation maps prescribe coolant pump flow, blower air flow, and inlet air temperature references, and they are obtained by comprehensive simulations of a high-fidelity multi-physics heating system model over a wide range of quasi-stationary operating conditions. A low-level PI controller is further designed for the full, allocation-related range of operating points to track the allocated inlet air temperature reference, while commanding the PTC heater power. The overall control strategy is validated through co-simulation with a high-fidelity vehicle model in comparison with an industry baseline strategy, demonstrating a considerable energy consumption reduction in both quasi-stationary and transient (heat up) conditions, as well as improved control performance in terms of shorter heat up intervals.