Abstract:

Harmonics are one of the unavoidable problems in motor design, especially for motors with permanent magnets. The most commonly used method of harmonic optimization is the skewed slot method. A variable-speed permanent magnet synchronous motor is taken as an example to describe the structure of the stator skewed slot. The reason why the chute can weaken the harmonics is that the skewed slot method can make the windings distributed. And the optimization of the no-load back EMF waveform and cogging torque with the skewed slot method is analyzed. The effect of the skewed slot method on the motor overload performance and axial electromagnetic force is analyzed. The skewed slot makes the conductor unparallel to the axis, which generates axial electromagnetic force and reduces the overload capacity of the motor. From the above conclusions, it can be concluded that the skewed slot method can optimize some of the performance of the motor and it can also degrade some performance. Designers need to choose the best skewed angle according to the specific performance requirements of the motor.

Key words: Skewed slot, back EMF, cogging torque, overload performance, axial electromagnetic force