The rotor yoke flux and air-gap flux density is varied with the magnet number per pole,the pole number and the thickness of the magnet are analyzed,and the differences between the magnet number per pole m≥2 and m=1(surface-mounted structure) are illustrated.

To reduce the leakage flux and improve the air gap flux density,auxiliary poles are added to the rotor structure.

Three methods,namely conventional analytical calculation,finite element calculation and practical measurement were used to verify the air gap flux density of the motor.

In order to investigate the impact of the size effect on its performance in designing axial-magnetized permanent magnet micromotor,the finite element method was adopted to simulate the magnetic field of this kind of dual rotor motor,and the flux density wave form distributed in the airgap was obtained.

In order to study the impact on its performance of the size effect in designing axial-magnetized permanent magnet micromotor,the finite element method was adopted to simulate the magnetic field of this kind of dual rotor motor,and the flux density wave form in the airgap was distributed.

The air gap magnetic flux density distribution in a brushless DC motor is analytically simulated.

This paper discusses the rule of the air-gap flux density varying with the magnet number per pole, the thickness of magnet and the pole number by static-steady electromagnetic field theory.