Torque characteristic investigation of a permanent magnet spherical motor

Compared with transmission systems assembled by some single degrees-of-freedom (DOF) electrical motors, three DOF motion can be achieved in a single permanent magnet (PM) spherical motor, which is a new research direction in the field of electrical motors. The structure and operation principle of a novel PM spherical motor are introduced. An effective three dimensional (3-D) electromagnetic torque finite element model of the PM spherical motor is established, and based on the model simulation is made about the torque which can drive the motor spin. The known motor prototype is analyzed and the typical torque characteristics of the motor are derived. Through analyses of torque characteristics, a method is derived which can effectively enhance the output torque of the PM spherical motor. With the results, theoretical guide is provided for configuration optimization and torque control of the PM spherical motor.