The Core of Vehicle Thermal Management
In the entire thermal management system, water-cooled plates, heat exchangers, four-way valves, and electronic expansion valves are all passive heat exchange/throttling components, only responsible for heat transfer and loop switching. Only the electric compressor can compress the refrigerant, establish system pressure differential, and drive the continuous circulation of the refrigerant; it is the active work core of the entire thermal management system. Without the compressor, heat pump heating, active cooling, and battery active temperature control all fail.
Vehicle Thermal Management Energy Chain:
Electric Compressor (Energy Input Core) → Valves/Heat Exchangers → Battery/Electric Drive/Cavity Heat Exchange Terminals
I. Working Principle of Electric Compressor: Electrical Energy → Mechanical Energy → Refrigerant Pressure Difference
1. Energy Conversion Link
High-voltage battery DC power → Three-phase inverter bridge → AC power → PMSM motor rotation → Compressor scroll plate compresses refrigerant → Establishes system high and low pressure difference → Refrigerant circulation and heat exchange
2. Control Closed Loop
● The vehicle VCU/thermal management controller sends the target speed and operating mode via CAN;
● The DSP/MCU runs the FOC vector control algorithm to calculate the three-phase PWM;
● The isolated gate driver amplifies the 3.3V PWM to 15V to drive 6 power transistors;
● The three-phase inverter bridge inverts the DC power into variable frequency AC power;
● The PMSM motor drives the compressor to perform work;
● Current, voltage, and temperature feedback are isolated and sampled back to the DSP for real-time correction of control parameters.
Four Core Functions
① Active Cabin Cooling: Achieves cabin cooling in summer through a refrigerant compression-condensation-throttling-evaporation cycle, making it the only cooling power unit in new energy vehicles.
② High-Efficiency Heat Pump Heating (Replacing High-Energy PTC): Absorbs waste heat from ambient air and motor/electronic control systems to heat the cabin and battery. Compared to pure PTC heating solutions, it can improve the low-temperature range by 10%~20% (the improvement is more significant in extreme low-temperature conditions below -20℃), and significantly reduce overall vehicle energy consumption in winter.
③ Full-Range Battery Temperature Control: In high-temperature conditions, refrigerant circulation removes battery heat, ensuring safe and stable ultra-fast charging; in low-temperature conditions, the heat pump circuit preheats the battery cells, stabilizing charging and discharging performance, slowing cell degradation, and extending battery life.
④ Tiered utilization of vehicle heat: First definition: Based on the priority of "motor waste heat → battery temperature control → cabin heating → environmental heat dissipation", the waste heat of the whole vehicle is dynamically scheduled to realize waste heat recovery and on-demand distribution, maximize the reduction of ineffective energy consumption and improve the energy utilization rate of the whole vehicle.
