Battery and motor technology have received great attention, but electric control technology is rarely mentioned?

Why in the three electricity technology , The battery 、 Motor technology has received great attention , On the contrary, electric control technology is rarely mentioned ？

In general , Yes 4 In terms of reasons ：

One 、 Some electric control technology , Driven motor 、 Battery technology covers

Now, permanent magnet synchronous motor and asynchronous AC motor are commonly used in electric vehicles , All belong to three-phase AC motors .

Their electric control algorithm adopts vector control (Vector sensorless control). in other words , When an electric car says that it adopts permanent magnet synchronous or asynchronous AC motor , By default, I announced what kind of electronic control algorithm I used .

This is the crystallization of human wisdom 、 A control method that embodies the spirit of reducing complexity to simplicity .

. The stator has a magnetic field , The rotor also has a magnetic field ;

. If the motor wants to turn , It is to control the electric field and the change of the magnetic field , Attract another magnetic field , Chain is current → The magnetic field → force → torque → Speed ;

. The difficulty lies in , It's like chasing girls , The two magnetic fields are too close to attract , It's too far away to attract , Plus the speed is so fast that it is really difficult to control ……

.1970 Around, Darmstadt University of technology and Siemens proposed Park Transformation , All at once, it's simplified , The world is clean ！

Three phase AC motor and vector control algorithm are strictly bound , You use it, I use it, and he uses it . Mention it or not , Can't change this fact . Mentioned words , It also takes up valuable advertisements 、 Poster space , It's better not to mention .

Two 、 The core electronic control algorithm has matured , It's hard to innovate

The peak of AC motor development is 20 century 60 to 80 years , The main driving force is ：

· Algorithm ： Space vector modulation control technology (SVPWM, Space Vector PWM).

· Signal hardware ： The invention and use of advanced processors , Bearer Algorithm .

· Power hardware ：IGBT Invention and commercial promotion of , Execute algorithm .

These three belong to the field of electronic control , But the algorithm is mature , It is almost impossible to improve ; The signal hardware carrying the algorithm has long been enough , There is nothing to mention . It's like not selling new games , that Nvidia There is no use for graphics cards .

Power hardware is also called power semiconductor , There is still room for progress , But we just don't seem to realize that this belongs to electronic control . This involves the next aspect ：

3、 ... and 、 Mentioned , But I didn't realize that this belongs to electronic control technology

Silicon carbide (SiC) technology , Everyone has heard of it ？ Don't you often mention it in the past two years ？ tesla 、 The reason why BYD's motor energy consumption is low , Just because I took the lead in using SiC Semiconductor technology .

You may question ：SiC MOSFET、IGBT It's all visible 、 Touchable hardware , How can we say it's electronic control technology ？

Then let me interpret this problem .

Whether it is permanent magnet synchronous motor (PMSM, Permanent-Magnet Synchronous Motor), Or asynchronous AC motor (IM, Inductor Motor ), If you want to rotate, you can't do without sine wave alternating current ：

· Algorithm ： The moment of this sine wave 、 cycle 、 phase , Is the SVPWM Algorithm to decide , That is, an algorithm composed of lines of code .

· Algorithm → The signal ： Algorithm into signal , It depends on the processor , That is, the chip .

· The signal → power ： Success rate of signal conversion , It depends on switching devices , That is, power semiconductor devices .

Only need to “ Switching devices ” Input a small power control signal ( for example 1 Maoqian sends a text message ), It can output / Disconnect the high power current —— This kind of small switching device , It is the legendary bipolar transistor ( abbreviation BJT,Bipolar Junction Transistor), Also known as triode .

You can see ,BJT Can control large current with small current 、 Can be 1 The penny lever levers 100 dollar , So it's also called “ amplifier “[1].

BJT Can finish “ Switching devices “ Basic functions of , But it also has a slow switching frequency 、 High switching loss 、 High driving power consumption , More importantly ： It wants to pry 100 Yuan , At least cost 1 dime , If I 1 I don't want to spend any money ？

Then you have to “ Flow control device ” Replace with “ Voltage control device ”, That is to say MOSFET(Metal-Oxide-Semiconductor Field-Effect Transistor Metal - Oxide semiconductor field effect transistor )[2].

above MOSFET Does the cross-sectional view look big ？ It doesn't matter , We just need to remember ：MOSFET There are also three poles , Only need Gate Extreme pressure ( Apply a voltage signal ) But don't pay , We can output on the other two poles / Disconnect the power current .

Abscissa is voltage signal , The ordinate is power current —— When there is no voltage , The power current is disconnected ; When the voltage is high enough , Power current conduction . picture source [3]

So it seems ,MOSFET Than BJT Much better , But there is a fatal problem when it is applied to the automotive field ： The withstand voltage is weak 、 Can't do high power . In general ,600V10A It's almost over ——400V You can barely use it , But the power is only 6kW, It's OK to build an electric bike ; As for the coming 800V System , That's definitely out of the question ！

The application scenario of electric vehicles is too harsh ,MOSFET My little body can't bear it , To do that ？ There are two ideas , One is to find help from outside , The second is to improve their own attributes from the inside , It takes a good blacksmith to make steel. .

As the saying goes , Be strict with others , Be lenient to discipline yourself —— The way to improve your attributes is always difficult , Let's go and find a helper first ！ therefore ,MOSFET Found the one just beaten by it BJT, The two constitute the withstand voltage range 600-6500V High power switching devices , That is to say MOSFET + BJT = IGBT (Insulated Gate Bipolar Transistor, Insulated gate bipolar transistor )[3].

We just mentioned BJT、MOSFET、IGBT It refers to semiconductors “ structure “, The default is based on Si( silicon )“ material “. therefore , Their full name should be “ material + structure ” The combination of , such as Si MOSFET、Si IGBT. Just for a long time , except Si Have no choice but to , Therefore, the material symbols are omitted .

SiC( Silicon carbide ) It is the third generation of semiconductor materials rising in recent years [4], It is a wide band gap semiconductor material , It can achieve high withstand voltage, and the chip is still very thin —— High withstand voltage 、 high power 、 high efficiency 、 Small size .

Improvement of material properties , It means that the semiconductor devices made of them have a wider range of applications [5]：

It also means that , We don't need to give Si MOSFET Find a helper to upgrade to Si IGBT The way to improve ability , You can follow the idea that forging iron still needs its own hard , Upgrade to SiC MOSFET That's all right. [6]！

So , From the algorithm → The signal → From the chain of power ,SiC MOSFET And IGBT It should be classified as electric control technology ！ We usually pay attention to when buying a car SiC The concept , But I didn't realize that it belongs to electric control .

Four 、 The threshold of understanding is high , Not easy to spread

Some electronic control algorithms have high understanding threshold , Not easy to spread .

Electric control has a core safety concept ： Functional safety (Function Safety).

The concept of functional security is very complex , Difficult to understand . Don't talk about it to consumers , Even say it to the engineer , Without relevant experience, it is also difficult to explain clearly .

occasionally , Don't say you can't explain clearly , Even make mistakes . Such as , Li Bin once said that single motors are all hooligans , Because multiple redundancy of dual motors is safer .

When he expressed this view , It involves the concept of electronic control function safety . Finally, the boss mentioned electric control once , Also wrong . Big guys can say wrong 、 Consumers can't tell right from wrong , It can be seen how difficult the concept of electronic control is to spread —— If you are the marketing director of a car company , Do you think it's a good idea to focus on electronic control ？