Electric cars are not a new invention. They have been around for a while; however, electric vehicles are becoming more popular with the increased outcry about the adverse effects of pollution. Electric cars are similar to standard vehicles, except they have batteries, and an electric motor replaces the engine. This motor converts the electric energy in the batteries into mechanical energy. It’s this mechanical energy that moves the car.
Motor manufacturers have developed different types of electric motors thanks to continuous innovation and technological advancements. However, for use in any automotive application, these motors should be efficient and have high starting torque and power density.
Here is a list of electric motors used in vehicles.
DC Series Motor:
A DC Series motor is a machine capable of producing high initial torque, and its winding connects in series with the armature winding. It is a motor popularly used back in the 1990s for transition applications. The primary purpose of a DC Series motor is to turn electrical energy into mechanical energy using the electromagnetic law. It is a suitable optional machine because it can withstand a sudden increase in load when at easy speed control.
The only disadvantage of the DC Series motor is that it needs high maintenance due to the brushes and commutators. The brushes wear and tear equally as the work done; therefore, you have to clean the debris around the brushes and regularly replace the worn-out ones. Keep the brushes at an equal distance around the commutator and parallel to the bars. Its features fall under Brushed DC Motors, and Indian railways still use this type of motor.
Brushless DC Motors:
This type of motor is an improved version of the DC Series motor that comes with permanent magnets used in place of brushes and commutators. It does not have a brush arrangement; therefore, commutation is done electronically due to the maintenance-free state. Brushless DC Motors have high starting torque and efficiency.
The main advantage of using this type of motor is that you will require less time to maintain it, and it does not use much money to repair and replace parts. In addition, it has characteristics that make it suitable for transition and a high-power density. Hub motors or belt-driven use Brushless motors due to their traction characteristics. Brushless DC Motors are in two major types:
- Brushless DC Motor Out-runner type.
These are also known as hub motors. The rotor is in the motor’s outer part, and the stator is inside. This brushless motor needs no external gear system meaning the vehicle is less bulky, and you require less space for the motor.
- Brushless DC Motor In-runner type.
These are also known as belt-driven motors. The rotor is in the motor’s inside part, and the stator is on the outside. This type of brushless motor needs an external gear system, making this in-runner configuration bulkier than the out-runner version. This motor is often utilised in low and medium-performance cars.
Permanent Magnetic Synchronous Motor:
This motor type for electric vehicles has similarities with the Brushless DC Motor, as both have magnets on the rotor and high power density and efficiency. The only distinction between the two motors is that Permanent Magnetic Synchronous Motor has sinusoidal back EMF, and Brushless DC Motors has trapezoidal back EMF. Permanent Magnetic Synchronous Motors are the best motor options for high-performing applications like electric vehicles as they have high power availability. They are expensive but worth the purchase as most motor manufacturers of electric vehicles uses this type of motor.
Three Phase AC Induction Motor:
This type of motor does not have high starting torque, unlike DC Motors, but you can increase the starting torque by using control techniques that make maximum starting torque available. Three Phase AC Induction Motor is a highly efficient motor option and can resist harsh environmental conditions. In lab equipment calibrations, these motors can achieve an efficiency of 92-95%. They require low maintenance and are suitable for traction applications. Tesla’s electric car uses this mode of motor, and Indian railways are using it too.
Switched Reluctance Motors:
This type of motor has double saliency and is simple to construct. It has a rotor that helps in high acceleration and is steel laminated. Switched Reluctance Motors are suitable for high-speed applications like electric vehicles that require high power density. The heat produced by the motor is confined in the stator, making the motor easier to cool. The only downside of this type of motor is that it has noise and control issues.
By understanding the different electric motors used in electric vehicles, you can easily pick the one that suits your needs. For instance, low-performance applications can use brushless DC hub motors, while induction motors or permanent magnetic synchronous motors are ideal for higher-performance applications. So don’t forget to factor in your requirements in terms of performance, operating conditions, and cost when making your choice.