Improvement of voltage resolution of a motor driver circuit by a multi-coil drive

In this paper, we propose a method to improve the voltage resolution and current harmonics in a multi-coil drive system that combines digital direct-driving technology and a multi-coil motor. In order to achieve both high resolution and low noise characteristics, a very high-frequency clock is required. A conventional PWM driver system generates large harmonics at the harmonic frequency of a carrier wave. However, using the proposed method, we can obtain a high-voltage resolution with a low-frequency clock, and we can drive a motor with a low supply of voltage. The reduction of current harmonics is also possible. The performance of the proposed method is confirmed via simulation and actual measured data.