At present, there are many high-power power electronic components in pure electric vehicles, but because of their low system integration and reliability, they cannot coordinate and work stably with each other. Centrally arrange the electrical equipment with power electronic conversion circuit as the core, such as the drive motor controller, on-board charger, DC/DC converter, and electric air air conditioner, to form an integrated power control unit (PCU), and uniformly design the circuit structure of the system, Drive unit, control unit, heat dissipation system, etc., not only can save materials, but also can reduce the occupied space, and the integrated power control unit has a new circuit topology structure, high integration, high reliability, and low cost.
The high-voltage principle of the pure electric vehicle integrated controller is shown in the following picture. The integrated controller mainly includes the main drive motor control unit, the DC/DC converter conversion unit, the auxiliary motor control unit, the high-voltage power distribution unit, and the insulation detection unit.
1.Main drive motor control unit
According to the vehicle controller control instructions, drive the vehicle's high-voltage auxiliary system (including the brake system and steering system) to work normally, and provide these high-voltage components with high-voltage electricity that meets the needs to achieve vehicle power-assisted steering or braking functions. The auxiliary motor control unit includes the main circuit of the DC/AC converter, the control circuit and the IGBT drive circuit.
2.DC/DC converter conversion unit
The high-voltage direct current provided by the power battery is converted into low-voltage direct current to charge the on-board auxiliary battery and supply power for the on-board low-voltage electrical appliances to meet the vehicle's demand for low-voltage power. The DC input end of the DC/DC converter can withstand a wide voltage range to ensure that it can be matched with different power battery systems. The conversion unit of the DC/DC converter includes the main circuit of the DC/DC converter, the control circuit and the drive circuit of the switch tube. 3. Auxiliary motor control unit
According to the control instructions of the vehicle controller, the vehicle's high-voltage auxiliary system (including the brake system and the steering system) is driven to work, and these high-voltage components are provided with high-voltage electricity that meets the needs to achieve vehicle power-assisted steering or braking functions. The auxiliary motor control unit includes the DC/AC converter main circuit, control circuit and IGBT drive circuit.
4. High voltage power distribution unit
The main function is to realize the reasonable and orderly distribution of the high-voltage power of the power battery in the various high-voltage subsystems. When the vehicle has a home, each system can act in accordance with the requirements of the vehicle and the driver's instructions to ensure the high-voltage power consumption of the vehicle. Safety. For high voltage circuits such as motors, heaters, air conditioners, DC/AC converters and DC/DC converters, DC fuses are set for short-circuit protection, with intelligent control functions and CAN communication and fault detection functions. The high-voltage power distribution unit mainly includes various high-voltage circuit fuses, contactors and their control systems.
5. Insulation detection unit
The main function is to detect the insulation between the high-voltage electrical system of the electric vehicle and the chassis, and feedback the insulation resistance value to the vehicle controller in real time, and the vehicle controller performs substation processing (alarm, power limit or power failure) according to the insulation resistance value , Effectively protect the safety of vehicles and personnel.
The integrated controller, as the core power control unit of the vehicle, is responsible for providing power to the electrical equipment of the vehicle, and plays a very important role. The electrical connections between the integrated controller and other peripheral devices are shown in the figure.