Research on Performance Simulation and Control Strategy of Indirect Heat Pump Systems for New Energy Commercial Vehicles

The heat pump system, as a core component of the thermal management system in new energy commercial vehicles, plays a critical role in improving vehicle range and economic efficiency through energy efficiency optimization and multi-mode cooperative control. This study employed R134a as the refrigerant and developed a multivariate cooperative control framework based on the proportional-integral (PI) control algorithm. The dynamic performance characteristics of the heat pump system under diverse environmental conditions were systematically investigated using the advanced modeling environment for simulations (Amesim). Focusing on two typical operating scenarios: high-temperature cooling at 40 ℃ and wide-range low-temperature heating (-15 ℃ to 0 ℃), a hierarchical control strategy integrating air-, water-, and dual-source coupled heat pump modes was proposed, along with a cascaded waste heat utilization model for motors. The results show that in the dual-target cooling mode, the system achieves simultaneous temperature control for the battery pack and cabin within 200 s, with the compressor power stabilized at approximately 7000 W and a coefficient of performance (COP) ranging from 2.5 to 3.0. Under low-temperature heating conditions, the dual-source heat pump mode achieved a heating COP of 2.1, representing 60% energy savings over traditional PTC heating systems.