Microprocessor Control of Dc Motor Drives

Abstract: There are various applications in industry which utilize DC drives to achieve high production levels and high quality standards. One of the common methods for bidirectional motoring control is accomplished by using a two- quadrant switching circuit. Some DC drive applications require braking which can be accomplished economically by using regenerative braking which is achieved by using a four-quadrant switching circuit. This braking scheme is more efficient, economical, and requires less maintenance as compared t o other types of braking. In this paper, the theory of regenerative braking is used to develop a control system for DC drives which is based on the operation of a four- quadrant switching circuit. This microprocessor based system is designed with a new integrated circuit (LMD 18200) which contains a four-quadrant switching circuit and on-board control logic. This system has many industrial and commercial applications and can be modified to conform to specific voltage, current, and horsepower ratings. Applications of this system range from larger industrial drives to small DC drives and servo motors such as those used in robotics, printers, and plotters. The system microprocessor can also be interfaced to other control units for process control applications.

Keywords: DC drives, Microprocessor Control, LMD 18200, Servo Motors, Control Systems.