Analysis of the three major parts of pure electric vehicles:
motor/battery/electronic control
Pure electric does not mean only changing the engine. Electric vehicles also have three major parts
Compared with ordinary diesel and gasoline engine trucks, the most obvious difference between pure electric vehicles is that the engine is different. Pure electric vehicles use electric motors instead of traditional diesel/gasoline engines, and use battery packs instead of fuel to provide power for the motor. One of the most important components is the electronic control system, which is composed of a battery management system and a control system. It manages the battery pack and controls the output of the battery energy and adjusts the speed of the motor, etc.
At present, the simplest pure electric truck in China is to replace the diesel engine with an electric motor, and weld a bracket to install the electric motor at the original engine position. This method is the most primitive and simplest, without any control system. Such pure electric trucks even retain manual transmissions.
After the continuous development of technology, pure electric trucks have developed from simple and crude replacement of electric motors to having a complete set of control systems, battery management systems, electric motors, etc. For a mature pure electric truck, it can be called a true pure electric truck only if it has mature three major parts (motor, battery, electronic control system).
Pure electric trucks have high requirements, and electric motors are the focus
Traditional internal combustion engines provide power by converting chemical energy into mechanical energy, while pure electric vehicles provide power to vehicles by converting electrical energy into mechanical energy. Compared with traditional diesel engines, pure electric trucks have higher requirements for engines (electric motors).
1. To meet the requirements of frequent start/stop, acceleration/deceleration and climbing of electric vehicles, the electric motor should have a large starting torque, good starting performance and good acceleration performance. Torque (similar to the engine's torque) is also an important criterion for measuring the quality of the motor.
2. Electric vehicle motors must have a wide constant power range to meet the needs of high-speed driving of electric vehicles.
3. During the driving process, the driver will adjust the driving speed and corresponding driving force of the electric vehicle at any time. At this time, the electric vehicle motor should have a wide range of speed regulation capabilities, with large torque at low speed and high power at high speed, to meet the driving needs.
4. To increase the continuous driving mileage after a single charge, it is generally required to obtain 85% to 93% efficiency in a typical driving cycle area. At this time, the electric vehicle motor should have good efficiency characteristics and obtain the best efficiency in a wide speed/torque range to improve efficiency.
5. In order not to occupy the vehicle's cargo space and increase its own weight, the electric vehicle motor is required to be as small as possible and as light as possible.
6. If the vehicle is to work for a long time in a harsh environment, with low noise during operation and convenient maintenance, the electric vehicle motor should have good reliability, temperature resistance and moisture resistance.
● There are many types of motors, and permanent magnet synchronous motors account for the majority
The motors are divided into DC motors, asynchronous motors, permanent magnet synchronous motors, switched reluctance motors, etc. These motors have their characteristics. At present, the most used in pure electric trucks is permanent magnet synchronous motors. Compared with other types of motors, permanent magnet synchronous motors have the characteristics of high efficiency and high specific power, but the control system of permanent magnet synchronous motors is relatively complex and the cost is relatively high. Some small pure electric truck companies do not currently have their own permanent magnet synchronous motor technology.
