The invention relates to a novel
magnetic field modulation type Halbach permanent magnetic direct
drive motor, which solves the problems of slow operation, large volume and complicated
system of the traditional motors by the
magnetic field adjusting effect of a
magnetic field adjusting ring in the motor. Simultaneously, an outer rotor adopts a Halbach permanent magnetic array capable of providing larger effective magnetic field
harmonic components and output torque, reducing the
magnetic flux density of the magnetic yoke of the outer rotor, and reducing the iron core loss. A motor
stator and the magnetic field adjusting ring are fixed by a
motor shaft, the outer rotor and the
motor shaft are rotatably connected, permanent magnets are evenly embedded on the outer rotor yoke along the circumferential direction, magnetic blocks of the magnetic field adjusting ring are evenly distributed along the circumferential direction, the sum of the number nr of pole-pairs of the permanent magnets and the number np of pole-pairs of armature windings is equal to the number ns of the magnetic blocks in the magnetic field adjusting ring, and the ratio of the number of pole-pairs of a
stator magnetic field to the number of pole-pairs of the permanent magnets is the speed
transformation ratio which can be realized by the device. By properly selecting the number of pole-pairs of the outer rotor of the motor and the number of the magnetic blocks in the magnetic field adjusting ring, the invention can be applied to low-speed direct drive occasions with different requirements.