The maximum magnetization can be achieved with the smallest external magnetic field, which has low coercivity and high permeability, making it easy to magnetize and demagnetize. Generally, soft magnetic materials have narrow hysteresis loops with coercivity below 100A/m.

Special Introduction to the Segmentation Problem of Permanent Magnets (Magnetic Tiles) in Electric Motors

1. What happens when the magnetic tile segments of a permanent magnet motor are different in length?

This depends on the specific situation, depending on whether the indexing is different on the circumference or the thickness is different in the axial direction? If the indexing on the circumference is not the same, it will definitely not be possible, as it will result in different numbers of poles and magnetic flux per pole of the motor. This is not allowed or necessary. If the axial size of the magnetic tile is inconsistent, it is acceptable, as long as it is fully arranged in the length of the iron core.

2. What is the impact of segmented magnetic tiles on the motor?

Segmentation is to reduce the eddy current loss of permanent magnets. Originally, it was a whole, just like the principle of slotting is the same.

3. What is the impact of the number of permanent magnet segments on motor performance?

The different number of permanent magnet segments has little effect on the no-load back electromotive force, cogging torque, direct axis inductance, and maximum ideal speed of the motor, and there is no obvious change or pattern.

Finally, permanent magnet segmentation can indeed reduce the permanent magnet flux, strengthen the direct axis armature reaction, reduce motor losses, and improve motor efficiency. However, these performance changes are almost unrelated to the number of permanent magnet segments, but rather to the total width of the magnetic bridge between the segmented permanent magnets. The material of the magnetic bridge between adjacent permanent magnets and the material of the rotor core are both silicon steel sheets, due to saturation, The magnetic resistance of the magnetic bridge is much greater than the magnetic resistance of the air gap, and the magnetic resistance of the permanent magnet is much greater than the magnetic resistance of the magnetic bridge. Therefore, most of the main magnetic flux passes through the air gap, and most of the weak magnetic flux passes through the magnetic bridge. Therefore, the direct axis armature reaction of the motor will be relatively enhanced, and the AC and DC axis inductance of the motor will be increased, which is conducive to improving the weak magnetic ability of the motor and expanding the range of constant power operation.