Week 3 Session 7
Compare the different motors used in EV and list down the advantages and disadvantages of each.
- Induction motor
- BLDC motor
- SRM motor
|
Induction motor |
BLDC motor |
SRM motor |
|
Operating Principle: Induction motors operate on the principle of electromagnetic induction, where the rotor rotates due to induced currents |
Operating Principle: BLDC motors use direct current to generate a magnetic field in the stator that interacts with the permanent magnets on the rotor to produce torque |
Operating Principle: SRMs operate based on the principle of magnetic reluctance, where the rotor aligns itself with the magnetic field generated in the stator to produce torque. |
|
Construction: Induction motors have a squirrel cage rotor |
Construction: BLDC motors have a rotor with permanent magnets |
Construction: SRMs have a simple rotor with no windings or magnets. |
|
Control: Induction motors are controlled by changing the frequency of the supply voltage |
Control: BLDC motors require a more sophisticated electronic controller to regulate the speed and torque |
Control: SRMs require a specialized electronic controller to regulate the current in the stator coils and produce torque. |
|
Cost: Induction motors are typically the least expensive of the three types |
Cost: BLDC motors are more expensive due to the more complex electronic controls and specialized components |
Cost: SRMs are a cost-competitive alternative to BLDC and induction motors for certain applications. |
|
Applications: Induction motors are widely used in industrial and commercial applications, |
Applications: BLDC motors are commonly used in applications requiring high efficiency and precise control, such as electric vehicles and medical equipment |
Applications: SRMs are often used in applications requiring high torque density and ruggedness, such as industrial drives and pumps. |
Induction motor advantages:
- Induction motors are simple and rugged in construction. Advantage of induction motors are that they are robust and can operate in any environmental condition
- Induction motors are cheaper in cost due to the absence of brushes, commutators, and slip rings
- They are maintenance free motors unlike dc motors and synchronous motors due to the absence of brushes, commutators and slip rings.
- Induction motors can be operated in polluted and explosive environments as they do not have brushes which can cause sparks
Induction motor Disadvantages:
- Requires separate power supply for the stator
- Poor starting torque
- Not suitable for high-speed applications
- Performance degradation under high temperatures
- Poor power factor
- Low power density compared to other motors.
SRM motor Advantages:
- Simple and robust construction
- Low cost
- High speed
- Less chance of hazard
- Long constant power range
- High power density
- Robust
- Fault tolerant
- Efficient
- Small
SRM motor Disadvantages:
- Very noisy
- Low efficiency
- Larger and heavier than PM machines
- Complex design and control
- Problems in controllability and manufacturing
- Low power factor
BLDC motor advantages:
- No rotor copper loss
- More efficiency than induction motors
- Lighter & Smaller
- Better heat dissipation
- More reliability
- More torque density
- More specific power
BLDC motor disadvantages:
- Short constant power range
- Decreased torque with increase in speed
- High cost because of PM