Variable characteristics DC motor by changing brush lead angle to expand the operation range

This paper proposes a variable characteristics DC motor by changing a brush lead angle to expand the motor operation range. In the proposed method, to change the brushes angle of DC motor means to change the current phase flowing into a motor. By using this technique, the back-EMF can be variable, the motor driving range can be expanded. The definition of brush lead angle in this study is firstly explained. Next, it is shown that the brush lead angle is considered as a same meaning with a current lead angle of Permanent Magnet Synchronous Motors (PMSMs) by adapting dq theory to the DC motor. Adding that, a simulation result that the brush angle of DC motor determines the operation range is shown and effectiveness of the proposed method is verified by experiments. Finally it clarifies the drive range expansion with efficiency in each brush angle.