Motor drives

Abstract

The widespread proliferation of power electronics and ancillary control circuits into motor control systems in the past two or three decades have led to a situation where motor drives, which process about two-thirds of the world's electrical power into mechanical power, are on the threshold of processing all of this power via power electronics. A typical motor-drive system is expected to have some of the system blocks. The load may be a conveyor system, a traction system, the rolls of a mill drive, the cutting tool of a numerically controlled machine tool, the compressor of an air conditioner, a ship propulsion system, a control valve for a boiler, a robotic arm, and so on. The power electronic converter block may use diodes, metal-oxide semiconductor field effect transistors (MOSFETS), gate turn-off thyristors (GTOs), insulated gate bipolar transistors (IGBTs), or thyristors. The controllers may consist of several control loops, for regulating voltage, current, torque, flux,speed, position, tension, or other desirable conditions of the load. Direct-current motors are extensively used in variable-speed drives and position-control systems where good dynamic response and steady-state performance are required. Depending on the application requirements, the power converter for a dc motor may be chosen from a number of topologies. © 2007 Elsevier Inc. All rights reserved.