An Energy-Efficient Control Allocation Strategy for PTC Heater-Based Electric Vehicle Cabin Thermal Management

Electric vehicles (EVs) experience substantially reduced driving range in cold weather, primarily due to cabin heating energy demands. This paper proposes a control allocation strategy for positive temperature coefficient (PTC) heater-based electric minibus cabin thermal management, aimed at minimizing energy consumption. The strategy is of a hierarchical structure, where a supervisory PI cabin temperature controller commands the heating power demand, which is then achieved through optimal allocation and low-level control of the cabin inlet air temperature, coolant pump flow, and radiator blower air flow control inputs. Based on the assumption of fast heating system dynamics relative to cabin thermal dynamics, quasi-steady-state optimization of control input allocation is carried out by employing a grid-search algorithm over a dataset resulting from high-fidelity simulations. For the system heat-up transient conditions, where the steady-state allocation proves to be suboptimal, dynamic programming is applied on a validated reduced-order model to optimize the control trajectories. Insights gained through control trajectory optimization are then used to develop a rule-based modification of the control allocation strategy for the heat-up scenario. Simulation verification of the overall control system demonstrates energy consumption reduction in the range from 4 to 12% when compared to the industrial baseline system across both steady-state and transient operating conditions.