Text/Peach Lee
Recently, a message about the recall of Tesla motors has aroused heated discussion among everyone. Tesla Motors (Beijing) Co., Ltd. and Tesla (Shanghai) Co., Ltd. have issued an announcement that they intend to recall some imported and domestically produced Model 3s sold between January 11, 2019 and January 25, 2022, starting april 7, 2022, for a total of 127785 units, including 34,207 imported Model 3 and 93,578 domestic Model 3.
According to the official description, the reason for this recall is that there are small manufacturing differences in the power semiconductor components of the rear motor inverter of the vehicle, which may cause the rear inverter to fail, resulting in the inverter not being able to control the current normally. Specifically, when the vehicle is in a parked state, it may not be able to start; when the vehicle is in a driving state, it may lose driving power, and in extreme cases, it may increase the risk of vehicle collision, and there are safety hazards.
I believe that many people will be curious when they see this news, what is an inverter? What are power semiconductor components? Why do these things cause such a big security risk? Don't worry, this issue will give you a simple science popularization.
We all know that the core technology of new energy vehicles is "three electricity", and the inverter is part of the electric drive system. New energy vehicles can run because the motor drives the wheels, and the power source of the motor is the battery, but the problem is that the power stored by the battery cannot directly drive the motor, because the power battery is stored in direct current, and the motor uses alternating current, so the inverter comes in handy at this time.
After the inverter receives the driving control instructions of the vehicle controller VCU, the direct current in the battery is converted into the three-phase alternating current required by the motor during the driving process, and the electric vehicle inverter will intelligently adjust the amplitude and frequency, the frequency controls the speed of the electric vehicle, and the amplitude controls the power size of the car; and in the braking process of the new energy vehicle, it can play a role in recovering the electric energy, and its performance is directly related to the power output performance of the motor and the endurance performance of the new energy vehicle, which is one of the core components of the new energy vehicle.
In general, the architecture of new energy vehicle inverters is mainly divided into two types, one is a separately packaged box inverter, which has the characteristics of easy assembly and modularization; the other is the integrated inverter design, which is usually summarized in the transmission system, and Tesla mainly uses this type of inverter.
It is worth mentioning that the core of the electric vehicle inverter is the power semiconductor device, which is mainly used to change the voltage and frequency, and plays a role in converting direct current to alternating current in the inverter, which is the key to the inverter to achieve power conversion. It is precisely because of its key role that electric vehicles are particularly demanding.
The quality of the power semiconductor components will directly affect the work of the inverter and then affect the performance of the motor, so there can be no problems in the production, which can be seen from the reason for the recall mentioned in Tesla's announcement as "a small manufacturing difference", which is also the reason why Tesla cars have been recalled in large numbers.
Some time ago, a Model 3 owner broke the news that when he was driving a vehicle at a high speed of 100km/h, the central control screen suddenly displayed the words "the vehicle cannot continue to drive, please stop immediately", even if the vehicle is deeply stepped on the electric door, there is still no response, which is estimated to be caused by the inverter power semiconductor components.
In view of the current problem, the official measures are on the one hand to upgrade the motor control software for the vehicles within the scope of the recall through remote technical means; on the other hand, for vehicles that cannot be recalled through the remote upgrade technology of the car, the relevant users will be contacted through the service center, the motor control software will be upgraded for the vehicle, and the rear motor inverter of the vehicle will be closely monitored, and the rear inverter with related failures will be replaced free of charge in time, thereby eliminating safety hazards.
summary:
The car looks like a big box that will move, but it is composed of countless related parts and systems, any one of the links of the error may lead to extremely serious consequences, I hope that the major car companies in the car manufacturing can be consumer safety as the most important, strict control of the car production process, for the problem car should also be dealt with in a timely manner.