New energy vehicle three-electric system
(battery, motor, electronic control)
1. Battery
Battery is an industry related to chemistry, mechanical industry, electronic control, etc. The key to the battery lies in the battery core. The most important materials of the battery core are the positive and negative electrodes, separator, and electrolyte. The well-known cathode materials include lithium iron phosphate, lithium cobalt oxide, lithium manganate, ternary, and high nickel ternary.
2. Electric drive
The electric drive consists of three parts: transmission mechanism, motor, and inverter. At present, the transmission mechanisms of electric vehicles at home and abroad all use single-machine deceleration, that is, there is no clutch and no speed change. In the future, various electric vehicle companies will increase the complexity of the transmission mechanism while reducing the demand for motors and motor rheostat, that is, improving performance and reducing costs.
The motor is composed of three parts: stator, rotor, and casing. The key points of motor technology are the stator and rotor. The rotor is the main drive motor of new energy vehicles, and it assumes all functions related to the movement of new energy vehicles. The motor of a new energy vehicle has forward and reverse rotation. Forward rotation is to drive forward, and reverse rotation is to reverse.
When a new energy vehicle is accelerating forward, the motor has negative torque. The accuracy of the torque means the speed of the new energy vehicle's acceleration. When an error occurs in the torque, the new energy vehicle that requires the motor to accelerate and mileage will need a battery that consumes the same amount of energy to complete. The cost of the battery is larger than that of the motor, so the efficiency and performance of the new energy vehicle motor are at a minimum. It's important. At present, there are three main categories of automobile-specific motor drive systems: DC motor drive systems, permanent magnet synchronous motor drive systems, and AC induction motor drive systems.
DC motors are widely used, but their disadvantages are low efficiency, large mass, large volume, and poor reliability. The new generation of electric cars has slowly stopped using this motor.
Induction motors have strong high temperature resistance and better environmental adaptability! The efficiency is not low and the cost is the lowest.
The speed range is also the widest, but the disadvantage is that the control is slightly complicated.
The magnetic field of the rotor is generated by permanent magnets, which avoids damage caused by magnetization.
The power consumption is higher, so the efficiency is higher than other motors! The size and quality are smaller, and the layout is more flexible.
An inverter is a device that converts DC power into AC power. If the inverter of an electric vehicle can support higher voltage, the corresponding voltage charging current will be larger and the power will be larger. This means that charging with the same current will result in a higher charging power. It can be enlarged proportionally, that is, the charging time will be shortened. If the support voltage of the inverter is increased, the heat generated by the inverter will increase accordingly during charging, so the heat dissipation problem of the IGBT module in the inverter needs to be solved. This is a key issue to improve charging efficiency. Currently, Toyota of Japan This research has been more in-depth, such as the application of silicon-carbon technology.
3. Electronic control
As the replacement of traditional engine (gearbox) functions, the performance of new energy vehicle motors and electronic control systems directly determines the main performance indicators such as climbing, acceleration, and top speed of electric vehicles. At the same time, the working conditions faced by the electronic control system are relatively complex: it needs to be able to start and stop frequently, accelerate and decelerate, require high torque at low speeds/climbing, low torque at high speeds, and have a large transmission range; hybrid vehicles also need to handle Special functions such as motor starting, motor power generation, and braking energy feedback.
In terms of electronic control, for ordinary OEMs, all they really have control over is the vehicle controller. The vehicle controller for new energy vehicles is not very different from that of traditional vehicles, and its maturity is relatively high.
In addition, the energy consumption of the motor directly determines the cruising range with a fixed battery capacity. Therefore, electric vehicle drive systems have special requirements in terms of load requirements, technical performance and working environment:
1. The drive motor must have higher energy density, achieve lightweight and low cost, adapt to the limited interior space of the vehicle, and must have energy feedback capability to reduce the energy consumption of the entire vehicle;
2. The drive motor has both high-speed and wide speed regulation and low-speed and high torque to provide high starting speed, climbing performance and high-speed acceleration performance;
3. The electronic control system must have high control accuracy, high dynamic response rate, and at the same time provide high safety and reliability.
As an important part of the new energy vehicle industry chain, the motor electronic control system's technology and manufacturing level directly affect the performance and cost of the vehicle.
