How Does An Electric Vehicle Motor Work?

by

Electric vehicles won’t be fantastic without electric motors, in fact, they won’t move an inch. Apart from working noiselessly, the electric motors found in EVs are more efficient than internal combustion engines and produce faster acceleration.

How exactly do electric motors work? This article details the operation of the fantastic pieces of engineering responsible for the quiet revolution shaking up the auto industry.

How does an electric vehicle motor work?

Electric motors have been around for a long time. Still, it was recently that they stood a chance to displace internal combustion engines in automobiles on an appreciable scale. They work on the basic principle of creating a magnetic field in a part of the machine, i.e., the stator, or the static part. When the magnetic field is displaced, it causes a rotating part, i.e., the rotor, to, well, rotate.

So basically, an electric motor converts electricity to mechanical energy in the form of rotation. 

The difference between an EV and an internal combustion engine car is the source of the energy that is converted into mechanical energy.

When you swap out the internal combustion engine in a car for an electric motor, the electric motor transmits the mechanical energy it produces to the tires for traction to occur. The electrical power required for the operation comes from the battery in the car, usually made from lithium-ion chemistry.

Electric car components diagram

What type of electric motor do electric vehicles use?

Can you pick an electric motor off the shelf and stick it in an electric vehicle? Of course not. Electric cars have a set of requirements that inform the type of electric motors used in them. For example, power and size requirements mean electric motors that use direct current (DC) cannot work for displacing the wheels. However, you may find them performing secondary functions like powering the windshield wipers.

The real workhorses are alternating current (AC) motors. They require a conversion circuit as the vehicle battery can only store DC.

AC motors, as used in electric vehicles, are of two types: asynchronous and synchronous. The former, also known as an induction motor, uses a stator powered by electricity to create a rotating magnetic field that then pulls the rotor into an endless chase. You will find asynchronous motors in EVs that are meant for high-speed operation.

Synchronous motors use the rotor itself as an electromagnet, which means its rotation speed depends on the frequency of the current powering the motor. They are ideal for driving situations that call for regular stops and starts at low speeds.

The electric motor in an EV is part of the electric powertrain. Other electric powertrain components are the power electronic controller (PEC) and gear motor, which helps to adjust the torque and how fast the wheels spin.

Electric vehicle makers usually optimize their motors to give the performance desired. Tesla, for example, has supplied their own motors to other brands to use.