Design studies on hybrid excitation motor for main spindle drive in machine tools

This paper presents a hybrid excitation motor for a main spindle drive in end- and face-milling tools which is operated with high speed 50,000 min^-1. The proposed motor has not only a permanent magnet but also the field coil which makes field weakening and strengthening control possible with taking no notice of the magnet demagnetization. In addition, the sum of iron and copper losses of the motor at the end-milling operation is significantly reduced by the field weakening control. 3D-FEM based design studies on the proposed motor for the target application are demonstrated.