Cogging force mitigation of tubular permanent magnet machines with magnet dividing

Cogging force produced in a tubular permanent magnet machines due to the interaction between the permanent magnets and the stator teeth causes an undesired vibration and noise. In applications such as robotics there is a need for precise position control and for this purpose force pulsation should be minimized. This paper presents a new method for mitigation of the cogging force. It consists of a proper segmentation of the permanent magnets (PMs). By appropriate choosing of the magnet block pitch, the cogging force can be effectively reduced. The validity of the effectiveness of the cogging force reduction technique is verified by finite element analysis.