In an electric vehicle (EV), electrical energy from the battery is converted into rotational energy through an electric motor. The electric motor is the key component responsible for propelling the vehicle by transforming electrical energy into mechanical energy (rotational motion). The process of conversion can be understood in the following steps:
Battery: The electric energy for the EV is stored in a high-capacity battery pack. This battery provides direct current (DC) electricity to power the electric motor.
Inverter: Before the electrical energy can be used by the motor, it needs to be converted from DC to alternating current (AC). An inverter performs this task. AC is used in the motor as it allows for more precise control of the motor's speed and torque.
Electric Motor: The AC electricity from the inverter is supplied to the electric motor. The motor consists of two main components: the stator and the rotor.
Stator: The stator is the stationary part of the motor and contains coils of wire that produce a rotating magnetic field when supplied with AC electricity. This field does not rotate but remains static.
Rotor: The rotor is the rotating part of the motor and is connected to the vehicle's wheels. It contains magnets or windings that interact with the rotating magnetic field generated by the stator.
Electromagnetic Induction: When the AC current flows through the stator coils, a rotating magnetic field is created. This magnetic field induces an electric current in the rotor (according to Faraday's law of electromagnetic induction) or causes the permanent magnets in the rotor to experience a force, depending on the type of motor (induction motor or permanent magnet motor).
Rotational Motion: The interaction between the rotating magnetic field in the stator and the induced current in the rotor causes the rotor to turn. This rotation is transferred to the vehicle's wheels, propelling the EV forward.
Speed Control: The speed of the electric motor can be controlled by adjusting the frequency and amplitude of the AC current supplied to the stator. This control is typically managed by the vehicle's power electronics, ensuring efficient and responsive performance.
The process of electrical-to-rotational energy conversion in an EV motor is highly efficient, making electric vehicles an increasingly popular choice due to their environmental benefits and overall energy efficiency compared to traditional internal combustion engine vehicles.