Introduction: Speaking of new energy vehicles, we can always hear professionals talking about “three-electrical system”, so what does “three-electrical system” refer to? For new energy vehicles, the three-electric system refers to the power battery, drive motor and electronic control system. It can be said that the three-electric system is the core component of the new energy vehicle.
motor
The motor is the power source of the new energy vehicle. According to the structure and principle, the motor can be divided into three types: DC drive, permanent magnet synchronization, and AC induction. Different types of motors have different characteristics.
1. DC drive motor, its stator is a permanent magnet, and the rotor is connected to direct current. Junior high school physics knowledge tells us that the energized conductor will be subjected to ampere force in the magnetic field, thereby causing the rotor to rotate. The advantages of this type of motor are low cost and low requirements for the electronic control system, while the disadvantage is that it is relatively large and has relatively weak power performance. Generally, low-end pure electric scooters will use DC motors.
2. The permanent magnet synchronous motor is actually a DC motor, so its working principle is the same as that of the DC motor. The difference is that the DC motor is fed with square wave current, while the permanent magnet synchronous motor is fed with sine wave current. The advantages of permanent magnet synchronous motors are high power performance, excellent reliability, and relatively small size. The disadvantage is that the cost is relatively high, and there are certain requirements for the electronic control system.
3. Induction motors are relatively more complicated in principle, but can be roughly divided into three steps: first, the three-phase windings of the motor are connected to alternating current to generate a rotating magnetic field, and then the rotor composed of closed coils is cut in the rotating magnetic field The magnetic field lines induce an induced current, and finally the Lorentz force is generated due to the movement of the electric charge in the magnetic field, which causes the rotor to rotate. Because the magnetic field in the stator rotates first and then the rotor rotates, an induction motor is also called an asynchronous motor.
The advantage of the induction motor is that the manufacturing cost is low, and the power performance is also good. I believe everyone can see the disadvantage. Because it needs to use alternating current, it has high requirements on the electronic control system.
Power Battery
The power battery is the energy source for driving the motor. At present, the power battery is mainly distinguished by the positive and negative materials. There are lithium cobalt oxide, ternary lithium, lithium manganate and lithium iron phosphate. Yuan lithium and lithium iron phosphate batteries.
Among them, the advantages of lithium iron phosphate batteries are low cost, good stability and long life, while the disadvantages are low energy density and serious battery life in winter. The ternary lithium battery is the opposite, the advantage is low energy density, and the disadvantage is relatively poor stability and life.
Electronic control system
The electronic control system is actually a general term. If it is subdivided, it can be divided into the vehicle control system, the motor control system, and the battery management system. A major feature of new energy vehicles is that various electronic control systems are closely related to each other. Some vehicles even have a set of electronic control systems to control all electrical equipment on the vehicle, so it is okay to call them collectively.
Since the three-electric system is a key component of new energy vehicles, if the three-electric system is damaged, there is no doubt that the cost of repair or replacement is very high, so some car companies will launch a three-electric lifetime warranty policy. Of course, the three-electric system is not so easy to break, so car companies dare to say a lifetime warranty.
Post time: May-06-2022