EV BASICS 1O2: How does an electric car work? (video) | Internal components and functions of all electric vehicles

How electric cars work? It's not complicated. All-electric vehicles have an induction motor instead of IC engines. Electrical energy stored in their battery pack powers the motor. It’s really as simple as that!. 

Here in this article, we try to explain the same basic operation with a bit deeper look in to the internal components, and how each of them contribute to the front/back movements, speed controls and brakes.

In practice, automakers use different technologies to integrate internal components; but the ‘core components’ and underlying ‘architecture’ is the same, in all the EVs across the world! They all have a ‘battery’ to store electricity, ‘inverter’ to convert the DC battery power into AC power that is required for the ‘induction motor’, ‘onboard charger’ and a ‘controller’ that manages all these components.

For example, let’s take an example of Tesla Model S components and innerworkings:

Schematic of a Tesla Model S (Image: Cliff's Riffs blog)

How do electric car motors work?

Tesla and most of the new generation electric vehicles use an induction motor for its main drive. The induction Motor has two main parts: the stator and the rotor – which are nothing but a collection of conducting bars/coils. 

When 3 phase AC power input is given to the stator, the coils in the stator produces a rotating magnetic field, that induces current on the rotor bars to make it turn. (In simple words: When two like poles (North-North or South-South of stator and rotor magnet poles come close, they will repel each other, that repel force turns the rotor).

via Gfycat

How is the speed controlled? | Motor control technique

The beauty of an induction motor is that its speed depends on the frequency of the AC power supplied. So just by varying the frequency of the power supply, we will be able to alter the drive wheel speed. This simple fact makes electric car speed control easy and reliable.

With the frequency range, the electric car motor’s speed can vary from 0 to 18,000 rpm (rotations per minute). This is a great advantage electric cars have, when compared to internal combustion cars. Internal combustion engines have a limited speed motor; moreover an IC engine does not produce direct rotational motion; The linear motion of the piston has to be converted to rotational motion through multiple accessories!.

How does the reverse gear and brake work in electric car | Regenerative braking

Realizing reverse gear mechanism is quite easy in an electric car. Just change the order of the power phase, the polarity of magnetic poles will change, and eventually make the motor rotation from clock-wise to anti-clockwise direction.

Did you know? Electric car can be driven efficiently with just one pedal?
In an electric car, as soon as you release the accelerator pedal the regenerative braking comes into action. During regenerative breaking, the same main induction motor becomes an electric generator This will generate electricity in the stator coils, which can then be stored in the battery pack after the conversion.

Do you want to know more? Check out this excellent video on regenerative braking from Kyle Drivers. Curious to learn more on How does a Tesla Model S work? Check out this excellent video from patreon.com/LearnEngineering which explains the working and features with help of animation. 

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