This is particularly true at lower speeds. The permanent magnet motor does not require current to be supplied to its rotor to generate the rotor field, therefore eliminating the rotor losses almost completely. When compared to induction or reluctance motors it also requires lower currents on the stator and has a bigger power factor, leading to smaller current ratings on the controller, and increasing the overall drive system efficiency.
Driving lower speeds at higher efficiency than an induction motor might delete the requirement of a speed reduction transmission, taking complexity out of the mechanical arrangement.
Some battery electric vehicles (BEVs) utilise both motor technologies - one on the rear axle and the other on the front axle. Depending on the requirements, the more efficient system can provide propulsion power, or activate both at the same time for maximum power.
This type of motor can generate constant torque and maintain full torque at low speeds.
The smaller size, lighter weight and less coil provide a higher power density.
With the absence of brushes, there are reduced maintenance costs.
In PMSM the heat is generated on the stator coils and there are no brushes and only minimum heat generated on the rotor, facilitating the cooling of the motor. As they run cooler than induction motors, the motor's reliability and lifespan is increased.
This type of motor can have a wide speed range with the use of Field Weakening and can adopt the maximum torque/current (MTPA) control strategy during constant torque operation.
Industries that use PMSM motors include Metallurgical, Ceramic, Rubber, Petroleum, Textiles, and many others. PMSM motors can be designed to operate at synchronous speed from a supply of constant voltage and frequency as well as Variable Speed Drive (VSD) applications. Widely used in electric vehicles (EVs) due to high efficiency and power and torque densities, they are generally a superior choice in high torque applications such as mixers, grinders, pumps, fans, blowers, conveyors, and industrial applications where traditionally induction motors are found.
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