Power circuits for small permanent-magnet brushless DC drives

Brushless DC drives incorporating motors with permanent-magnet excitation are being used in a rapidly-expanding range of applications, including the computer peripheral, automotive and machine tool industries. The overall dynamic torque producing capability of the drive is critically dependent on the interaction between the motor and power switching circuit. The authors examine various power circuit configurations and discuss their comparative merits, paying particular attention to the trade-offs between circuit complexity and overall drive performance