Electric vehicles are not new to the world, but technological advancement and increased concern about pollution control have given them the label of future mobility. Traditional cars have a negative impact on the environment due to fuel consumption and subsequent CO2 emissions, resulting in air pollution, whereas EV cars produce none at all. Electric motors used in automotive applications should have features such as high starting torque, high power density, high efficiency, and so on.
Electric motors of various types are used in electric vehicles, including DC Series Motors, Brushless DC Motors, Permanent Magnet Synchronous Motors (PMSM), Three Phase AC Induction Motors, and Switched Reluctance Motors (SRM). Among these motors, you’ve probably heard of the BLDC motor, which is very popular in EVs.
What is BLDC ( Brushless DC) Motor ?
It is obvious from its name that BLDC motors have no brushes.The stator is equipped with coils wound with electromagnets while Permanent magnets are attached to the rotor. Electrical commutation is used to convert electrical energy into mechanical energy.
This is a significant difference from traditional brushes DC motors, as the latter can have both stator and rotor composed of electromagnets to increase magnetic fields.The torque of the brushless motor is caused by the magnetic interaction imposed by the electromagnets on the permanent magnets.
Brushless motors are now far more common than brushed motors. Both, however, can be found in a wide variety of applications. Brushed direct current motors are still widely used in household appliances and automobiles. They also have a strong industrial niche due to the ability to change the torque to speed ratio, which is unique to brushed motors.
A DC brushless motor may have an “Out runner” or an “In runner” layout.The rotor of an in-runner motor is located on the inside of the stator. The rotor is located on the outside of the stator in the case of an out-runner motor.
In runner BLDC Motor: In this type, the rotor of the motor is located inside, while the stator is located outside. Because these motors require an external transmission system to transfer power to the wheels, the In-runner configuration is slightly larger than the out-runner configuration. Which leads to even higher build volume and mechanical losses.
Out runner BLDC Motor : The rotor of the motor is located outside, while the stator is located inside. Because the wheel is directly connected to the exterior rotor, it is also known as a hub motor.
This type of motor does not necessitate the use of an external gear system. In a few cases, the motor incorporates planetary gears. Because it does not require a gear system, this motor reduces the overall size of the vehicle. It also eliminates the need for a space to mount the motor. With the same build volume, outrunner motors can achieve much higher torque levels than inrunner motors. Inrunner motors are frequently equipped with transmissions or gearboxes to compensate for their lower torque.(already explained above)
Out-runner BLDC is commonly used in Pure EV’s Etrance NEO, TVS iQUBE, etc.
Why BLDC motor is so popular in Electric Vehicles ?
Brushless DC Motors are used in the majority of Electric Scooters and Electric Motorcycles.Many two-wheelers, including the Ather 450X, Pure EV Etrance Neo, and Chetak Electric, use BLDC motors.In addition, many three-wheeler manufacturers, such as Goenka Electric Motors, Speego Vehicles, and Kinetic Green, use BLDC motors.
- BLDC motors have a higher torque-to-weight ratio, which is important for electric vehicles because it allows us to make the vehicle lighter while still achieving adequate torque.
- Because BLDC motors do not have brushes, they are more reliable because there is less equipment to deal with. As a result, it is also easy to maintain.
- In comparison with brushed DC motors, BLDC motors are considered more energy efficient. The lack of friction in brushes enables BLDC motors to convert more electrical power into mechanical power, which is why they are more efficient than brushed motors.
- Because of the lack of friction in the brushes, BLDC can operate without producing any mechanical noise.As a result, the electric vehicle can move more quietly.
- Unlike conventional DC motors, which use brushes to operate, BLDC motors do not produce sparking.This is an intriguing feature of brushless motors because it allows them to be used in environments where sparks are hazardous. For example, in environments with flammable gases.