What is pure electric drive technology?

The electric drive system of pure electric vehicle of Pacific Auto Network replaces the internal combustion engine and transmission of traditional automobile, and the vehicle is driven by power battery, inverter and motor transmission unit. When the driver steps on the accelerator pedal, the vehicle control module will control the power battery to output electric energy, and then control the inverter to drive the motor to run, and the torque output by the drive motor will drive the wheels to rotate through the gear mechanism, thus realizing the forward or backward movement of the vehicle.

The traditional automobile-driven vehicle relies on the internal combustion engine to do work, changes the transmission ratio and rotation direction of the output power through the transmission, and then drives the vehicle through the transmission shaft and wheels.

The working principle of power transmission for pure electric vehicles is as follows:

1) Basic drive components The main components of the pure electric vehicle drive system include power battery, inverter and speed change unit with motor.

Figure 3-2-3 is a schematic diagram of the drive system of a typical pure electric vehicle. In the application of new energy vehicles, the circuit unit between power battery pack and inverter is generally called BDU (battery connection unit).

2) The driving power source of a pure electric vehicle in the basic driving process is the power battery, but unlike traditional vehicles, the electric energy from the power battery is not always in the output state. In pure electric vehicles, there is also a mechanism to recover the useless energy when braking the vehicle and recycle it into the power battery.

There are two main paths for energy flow in the driving process of pure electric vehicles:

(1) When the vehicle is running, the energy from the power battery passes through the BDU and inverter, and then enters the motor speed change unit to drive the vehicle.

(2) When the braking energy is recovered for braking or vehicle deceleration, the motor in the transmission unit will become a generator, and the energy will return to the power battery through the inverter and BDU to charge the battery.

3) The main control module Pure electric vehicle can respond quickly and drive the vehicle smoothly under different road conditions, and meet the needs of drivers. Not only do it rely on the above power components, but the whole drive system also needs a set of perfect control modules. Namely vehicle controller (VCU), motor controller (MCU) and battery management system (BMS). These three controllers are the core technologies of pure electric vehicles, which have an important impact on the power, economy, reliability and safety of the whole vehicle.

(1)VCU location: usually installed on the vehicle body, such as in the cab.

Function: The main control module of vehicle powertrain is similar to the function of traditional vehicle powertrain control module PCM.

VCU is the core electronic control unit to realize vehicle control decision. VCU judges the driver's driving intention by collecting signals such as accelerator pedal, gear and brake pedal. By monitoring vehicle status information (vehicle speed, temperature, etc.). ), the VCU will send control commands to the power system and power battery system after judgment and processing, and control the operation modes of other systems of the vehicle at the same time.

(2)MCU location: usually located inside the inverter.

Function: It is the main control module of the motor, receiving VCU signals and controlling the running direction and output power of the motor.

(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)