A bipolar-starting and unipolar-running method to drive an HDD spindle motor at high speed with large starting torque

This paper presents a method to drive an HDD spindle motor at high speed with large starting torque by utilizing a bipolar-starting and unipolar-running algorithm. It proposes a novel inverter circuit to switch from bipolar to unipolar drive, or vice versa. It also develops a DSP-based BLDC motor controller not only to drive the BLDC motor with bipolar or unipolar method, but also to switch from one method to the other at any speed. And the effectiveness of the proposed method is also verified by using the developed controller experimentally