Finally found the reason for the high efficiency of permanent magnet motors

The main reasons for the high efficiency of permanent magnet motors can be attributed to the following aspects:

1. High magnetic energy density: Permanent magnet motors use permanent magnets to generate a magnetic field, which can provide high magnetic energy density and generate a strong magnetic field in a smaller volume and weight.

2. Reduce energy loss: Due to the high efficiency of permanent magnets, the motor requires less current to generate the same torque, which reduces copper loss (I ² R loss) caused by current flow.

3. High efficiency operating area: The design of permanent magnet motors enables them to maintain high efficiency over a wide operating range, as the magnetic field strength of permanent magnets is relatively constant and does not fluctuate significantly due to changes in motor load.

4. Simple structure: Permanent magnet motors usually do not require the excitation winding in the electrically excited motor, which reduces energy loss inside the motor and simplifies the structure of the motor.

5. High power density: Due to the high magnetic energy density of permanent magnets, permanent magnet motors can achieve high power output in a small volume, which means they can provide high efficiency in a compact space.

6. Good thermal performance: The design of permanent magnet motors usually allows for better heat dissipation performance because they have fewer conductive components and lower heat generation.

7. Reduce maintenance: Due to its simple structure, permanent magnet motors usually require less maintenance, which helps to reduce downtime and improve overall operating efficiency.

8. High control accuracy: Permanent magnet motors, combined with modern control technology, can achieve more precise speed and position control, which improves the overall efficiency of the system in applications that require precise control.

9. Energy feedback: In some applications, permanent magnet motors can also achieve feedback of braking energy, further improving the energy efficiency of the system.

10. Long term stability: The magnetic properties of permanent magnet materials have good stability over time, which means that the motor can maintain high efficiency during long-term operation.

Due to these advantages, permanent magnet motors have become increasingly popular in many modern industrial applications, such as electric vehicles, wind power generation, industrial automation equipment, etc. However, permanent magnet motors also have some limitations, such as sensitivity to high temperatures and relatively high costs, which need to be considered in the design and selection of motors.