Distributed cooling system for pure electric vehicles
Since the suitable temperatures of power batteries, drive motors, and motor controllers are inconsistent, the use of a distributed cooling system can control the objects more specifically and achieve better cooling effects. The test bench is mainly composed of a powertrain module, a liquid flow heat exchange module, a charging and discharging module, a bench control module, and a data acquisition module. The host computer sends CAN signals to the BMS and MCU through the simulated VCU to control the motor to run in the target state. The main heat sources are power batteries, drive motors, and motor controllers.
There are 12 temperature measurement points inside the battery pack, one for the drive motor and one for the motor controller. These data are read through CAN protocol communication.
Basic components of distributed cooling system
Before studying the control method of the cooling system of pure electric vehicles, it is necessary to analyze the cooling system of pure electric vehicles in detail. Liquid cooling is used for power batteries, and another liquid cooling circuit is used for motors and motor controllers. Considering that the suitable operating temperature of the motor is higher than that of the motor controller, the coolant first flows through the motor controller and then through the drive motor. The vehicle controller controls the two water pumps and two fans of the two independent cooling systems according to the collected inlet and outlet temperature values of the battery and motor cooling circuits.
The distributed cooling system uses an independent low-voltage power supply and is mainly composed of a constant temperature water tank, a flow meter, a brushless DC water pump, an air-liquid radiator, a stepless cooling fan and various pipe valves. The main consideration for selecting a brushless water pump and a brushless fan is that the output power of the water pump and fan can be adjusted according to the state of the cooling system, thereby reducing the energy consumption of the cooling system.
