Emerging electric motor technologies

These motors eliminate the need for a commutator, which is common in traditional DC motors and can cause heating and maintenance issues. Instead, they use winding coils that electronically detect rotor position for commutation. This means BLDCs have higher efficiency, more precise control, and faster response time. BLDC motors are increasingly used in residential and commercial applications requiring long operation periods, as well as in automotive traction. Their popularity is growing in electric vehicles and aviation due to advancements in electronic control systems.

These motors use a rotor that rotates synchronously with the stator’s magnetic field. The rotor is made from ferromagnetic materials, which reduces reluctance as it aligns with the magnetic fields. Since there are no windings or permanent magnets in the rotor, magnetic core losses are significantly reduced, leading to improved efficiency and higher reliability with lower maintenance.

These motors are a type of synchronous reluctance motor that uses permanent magnets. These magnets are made from rare-earth materials, which can increase costs and raise sustainability concerns.

These types of motors are gaining popularity because of their simple and robust design compared to DC motors, permanent magnet motors, and induction motors. In SRMs, power is supplied to the stator, making the mechanical design simpler. They use reluctance torque for rotation, controlled by power-switching transistors. SRMs are well-suited for various speed applications because their rotor has no windings or permanent magnets, resulting in low inertia.

No-load losses are energy losses in motor components that occur even without a load. They include:

• Iron losses: Energy used to manage changes in the magnetic field in core. These can be minimised by using higher-quality steel and optimising core design.
• Windage and friction losses: Caused by friction with air and ball-bearings. These can be reduced by selecting better bearings and improving cooling capability.

Load losses change based on the load applied and include:

• Stator copper losses: Heat generated in the stator’s copper windings, also known as I2R losses. These losses can be reduced by using low-loss steel and optimising the stator shape to enhance magnetic fields.
• Rotor losses: Result from resistance to current in the rotor and iron losses. These can be minimised by using conductive bars and rings to lower rotor resistance.
• Stray load losses: Caused by misalignment of the stator and rotor, as well as deterioration of magnetic materials, along with shear losses caused by machining of rotors. These can be reduced by using electronic control systems to monitor misalignment and magnetic flux leakage.