A DC/DC converter refers to an electrical device that converts one voltage value into another voltage value in a DC circuit. There are buck converters, voltage regulator converters, and boost converters for new energy vehicles. Among them, the buck converter is installed in almost every new energy vehicle. Its main function is to convert the high voltage of the power battery into low voltage to charge the battery and power the low-voltage electrical equipment of the vehicle. What are the functions of the DC/DC converters of new energy vehicles? Let's learn about these aspects together.
Application of DC/DC converters in pure electric vehicles
The application of DC/DC converters in pure electric vehicles mainly includes charging low-voltage batteries, powering low-voltage electrical equipment, energy recovery during deceleration or braking, and providing the voltage required for the drive motor.
During the driving process of the vehicle, the DC/DC converter converts the power battery voltage into the voltage required by the motor, and then converts the DC power into AC power through the inverter to drive the motor.
When the vehicle decelerates and brakes, the DC/DC converter converts the electric energy generated by the vehicle deceleration/braking into the power battery through voltage conversion to complete energy recovery.
Most importantly, the DC/DC converter converts the high voltage of the power battery into a low voltage to charge the low-voltage battery, and at the same time supplies power to the low-voltage electrical equipment of the vehicle.
Application of bidirectional DC/DC converters in hybrid vehicles
When the hybrid vehicle starts/vehicle speed is very low, the engine works in the low efficiency area, the energy management system will cut off the fuel, stop the engine, and only the motor provides mechanical energy. At this time, the DC/DC converter converts the power battery voltage into the voltage required by the motor, and then converts the DC power into AC power through the inverter to drive the motor to operate.
When the car is driving normally, the engine is started at this time to output two energy paths, one to provide mechanical energy for the car to run, and the other to make the motor work in the power generation state to charge the power battery until it reaches a reasonable state, in order to provide auxiliary energy or recover braking energy when accelerating and climbing. The DC/DC converter converts the electric energy generated by the motor into the power battery through voltage conversion to complete the charging.
When the hybrid vehicle climbs/accelerates, in addition to the normal operation of the engine, it is also necessary to start the power battery to output electric energy, so that the motor works in the electric state to provide auxiliary mechanical energy, increase the driving force of the wheels, and make the engine always work in the optimal efficiency range.
Application of bidirectional DC/DC converter in composite power supply of new energy vehicles
The bidirectional DC/DC converter is connected in series with the supercapacitor. When the vehicle accelerates, the DC/DC converter transfers the extra large current provided by the supercapacitor to the inverter. When decelerating and braking, the DC/DC converter transfers the energy fed back by the motor to the supercapacitor, so that the energy is stored in the supercapacitor.
The DC/DC converter is connected in series with the supercapacitor, and the supercapacitor is connected in parallel with the power battery to form a composite power supply. This connection method is more suitable for auxiliary energy storage systems of new energy vehicles.
