Fast Response Reversible Brushless DC Drive with Regenerative Braking

Drives used in machine-tool and robotic applications require four-quadrant operation and demand smooth starting and acceleration. The use of ac machines in these high-performance drives eliminates many of the drawbacks attributable to the brushes and commutator of dc motor drives. In this paper, a simple control technique for the permanent magnet brushless motor is presented which incorporates regenerative braking and reversing and yields fast response for servo operation. The novelty of this technique lies in the method of obtaining pulse-width-modulation of the inverter and the use of the same circuit for regenerative braking. Simplified analysis of this technique as well as the test results of the drive under open-loop and closed-loop speed control modes are presented.