Motors & Drives
In an ICE vehicle there is not much freedom in designing a place for engine. In most cars motor is in the front, lately also front wheels are the drive wheels. This not an ideal solution but it's cheaper to manufacture. Some ICE vehicles have front motor and rear wheel drive for example many BMW-s so they have to transmit the power from motor to gearbox and then with long shaft to the rear axle. It can be even more complicated than that, in case of four wheel drive vehicles. Then there is a problem that ICE cannot produce any power from standstill that means that it has to rotate to start the car moving this means it needs a clutch. Next problem with ICE engines is that they make usable power and torque only in a small band of revolutions usually 0 - 6000rpm that means they need a gearbox, nowadays even 8 or 9 gears! Electric motor is free of those problems it can put out maximum torque from standstill so now clutch needed. Electric motors usually rotate between 0 - 13000rpm so no need for gearbox either, this makes electric cars driveline cheaper to produce, shorter, lighter and more efficient. Electric cars use electric motors not engines and electric motors are much much smaller and there is no problem in making many smaller motors for front axle and other to the rear axle. Then there are two motors on the car and there can be four wheel drive or the software can decide when it is better or more economical to use front or rear or both motors. Nowadays EV electric motors are one package with reducer and differential some even have the power electronics (controller or inverter) integrated to it. There has been prototype cars or hyper cars with motor for each wheel this gives ability to get better control over the car on racetrack and so on. That kind of system can for example in the corner left side wheels decelerate and right side accelerate to make the car turn better.
Asynchronous and syncrhonous motors, IGBT-s inverters or controllers.
Electric cars have used over hundred years brushed DC motors. 21 century electric cars all are equipped with motors without brushes because brushes can wear out in about 20 000km. In 2010 Japanese manufacturers Nissan and Mitsubishi started manufacturing or found manufacturer of brushless direct current motors (BLDC). American companies have used AC induction motors starting from 1996? GM EV1 and later Tesla Model S. Audi E-tron uses also AC induction motor. Those two main types of motors both are wery reliable. AC induction motors are known for good price and super good reliability from manufacturing and workshops. It is main motor type wich allowed or lead to industrial revolution wich needed to get rid of steam maschines and build factories more efficiently and save energy. Some have tried to use bigger AC induction motor from lathe or drill press on a converted car. But its not that easy. I have driven one in Räpina Dacia Sandero wich made on some rpm's same noise as lathe but it drove and more than 100km on one charge. Unfortunately the car was not as fast as it use to be with petrol ICE engine. GM, Tesla and others have designed special AC induction motor for their cars. Those motors are liquid cooled some have controllers integrated. All of them are attached to special reducer and differential. Also there are many modifications compared to industrial motors wich makes them better suited for traction application. Tesla used this type of motor mainly to get 416 hj (310 kW) and 600 Nm of torque. It was needed to outperform most ICE cars at 2012. They did quite well, it was five door luxury electric car with 5 seats and was faster at 0…100km/h then most supercars. Tesla Model S with only rear drive AC motor did it in 3,2seconds.
Tesla Model S rear motor
AC induction motor is best for big power and torque but somewhat not so good at efficiency. Brushless Synhronous motors (BLDC) are little bit better at that but sometimes it is more expensive to manufacture them because they need neodymium magnets. As we now that automotive engineers have two choices about drive motors. BMW, Koreans, Japanese manufacturers have chosen brushless synchronous motors Audi has AC induction motors. Synchronous motors allow the car to drive further on one charge because of better efficiency. At year 2020 most of electric cars electrical systems work at 400V. Only one manufacturer Porche has 800V electrical system.
Mitsubishi i-MiEV motor Y41 49kW 170Nm
Brushless DC motor or synchronous motor with reducer and differential. Liquid cooled stator
Since electric motors are wery powerful and can create wery high torque but they need three phase AC (Alternating current). EV-s have batteries as energy source but batteries as chemical energy storage devices output only DC direct current. So we need a device that can convert and invert DC into 3 phase AC. Those devices are called on small vehicles like ebikes electric motor controllers but in the car industry mainly inverters because of their ability to create AC from DC and at the same time make a sinewave like signal with suitable frequency for the motor.
