When it comes to the three major components of traditional fuel vehicles, everyone will subconsciously say:
engine, gearbox, chassis, but when it comes to electric vehicles, it is very different from fuel vehicles, although the overall appearance is a “car” , but the internal structure has undergone earth-shaking changes; there is no engine and gearbox inside the electric vehicle, and the three major components are replaced by: battery, motor and electronic control system; Convert electrical energy into kinetic energy, drag the vehicle, and complete the operation of the driving process.
The double-sidedness of the motor
At present, the electric vehicles that we can buy on the market all have a “special” function called energy recovery; the energy recovery system is to recycle the kinetic energy wasted by the vehicle during taxiing and braking into electrical energy. In this process, many small partners may not know the specific process; some enthusiastic netizens have asked the author, is this energy recovery a small generator in the electric vehicle and linked to the wheels? In the process of braking and coasting, the wheels drive the generator, convert the kinetic energy into electrical energy, and then send the electrical energy back to the battery?
In principle, this process is completely correct, but there is no such thing as what everyone said inside the electric vehicle: a small generator is installed separately; there is no generator, so what is going on?
At present, the electric vehicles on the market all use AC motors for kinetic energy output, and AC motors currently use permanent magnet synchronous motors and AC asynchronous motors. ;At present, although there are differences in the internal motors of electric vehicles, they are all AC motors. Inside the motors, there are stators and rotors. After the stator windings are connected to the AC power, the stator rotating magnetic field is generated, and the rotor windings receive the stator rotating magnetic induction to generate induced current. , and then cause the motor to rotate. In this process, the motor outputs the electrical energy to the inside of the motor, and then causes the motor to turn on and rotate as kinetic energy, and then outputs the kinetic energy of the motor to the vehicle drive system, and the electric vehicle starts to move.
From the normal principle, the motor converts electrical energy into kinetic energy, while the workmanship of generators and motors is just the opposite, converting kinetic energy into electrical energy.
Although the motor is different from the generator and has a completely different working principle, it is completely the same in structure. It is composed of a stator and a rotor, and both use the principle of electromagnetic induction to work. Since electromagnetic induction is reversible, electric vehicles Isn’t it amazing that the internal motor can be used as a generator when needed?
When the electronic power-assisted braking of the electric vehicle intervenes, and when the electric vehicle is coasting, the motor is in a static state because there is no power input, and during the power-assisted braking and coasting, the vehicle will drag the motor in the opposite direction to rotate. When it is forced to rotate in the opposite direction, it is in the generator state. Because the electromagnetic induction mentioned above is to convert the wasted kinetic energy of the vehicle when the motor is forced to rotate, it is converted into electric energy after passive rotation, which is then output to the interior of the battery; It is precisely because of the multi-faceted nature of the motor that electric vehicles can have an energy recovery system and further promote environmental protection projects.
AC or DC?
All electric vehicles use AC motors, but we know that the output of the power battery pack is direct current (the fast charging system is to directly charge the direct current into the battery), so inside the electric vehicle, an inverter is required to The DC power of the battery is converted, and the DC power is converted into AC power and then output to the motor. When the motor is “forced” to become a generator, the output is also AC power. This AC power also needs the inverter to be converted into DC power and recharged to the battery. , the working state of the entire energy recovery of the stroke.
There are also many first-generation electric vehicles that do not have energy recovery systems. Most of them use DC motors internally, and DC motors can complete energy output without inverters, but whether they are AC motors or DC motors, as long as they are “forced” to become When the generator is used, the electric energy generated by forced rotation is AC power. In the DC motor electric vehicle without inverter, the generated AC power can only be wasted. Therefore, those electric vehicles without energy recovery system, Most of them are “old cars” with DC motors.
Compared with traditional fuel vehicles, the internal structure of electric vehicles has many steps and principles of energy conversion. The energy recovery system is only a “tiny” part of electric vehicles, but it can play a key role in many places. When the FAW-Volkswagen ID.6 CROZZ was used, it only had 15+km of battery life at the top of Zeduo Mountain, and then started going down the mountain. During the downhill journey, the energy recovery state was turned on throughout the journey. At the bottom of the mountain, the battery life not only did not decrease, but increased a lot. At critical moments, energy recovery can indeed reflect the “environmental protection” attributes of electric vehicles.