The concept of switched reluctance machines (SRMs) was established as early in 1838 by Davidson and was used to propel a locomotive on the Glasgow–Edinburgh railway near Falkirk [1]. However, the full potential of the motor could not be utilized with the mechanical switches available in those days. The advent of fast-acting power semiconductor switches revived the interest in SRMs in the 1970s when Professor Lawrenson’s group established the | 13 Switched Reluctance Machines Iqbal Husain Introduction The University of Akron Advantages Disadvantages SRM Configuration Basic Principle of Operation Voltage Balance Equation Energy Conversion Torque Production Torque-Speed Characteristics Design Converter Topologies Control Strategies Control Parameters Advance Angle Calculation Voltage-Controlled Drive Current-Controlled Drive Advanced Control Strategies Sensorless Control Applications Introduction The concept of switched reluctance machines SRMs was established as early in 1838 by Davidson and was used to propel a locomotive on the Glasgow-Edinburgh railway near Falkirk 1 . However the full potential of the motor could not be utilized with the mechanical switches available in those days. The advent of fast-acting power semiconductor switches revived the interest in SRMs in the 1970s when Professor Lawrenson s group established the fundamental design and operating principles of the machine 2 . The rejuvenated interest of researchers supplemented by the developments of computer-aided electromagnetic design prompted a tremendous growth in the technology over the next three decades. SRM technology is now slowly penetrating into the industry with the promise of providing an efficient drive system at a lower cost. Advantages The SRM possess a few unique features that makes it a vigorous competitor to existing AC and DC motors in various adjustable-speed drive and servo applications. The advantages of an SRM can be summarized as follows Machine construction is simple and low-cost because of the absence of rotor winding and permanent magnets. There are no shoot-through faults between the DC buses in the SRM drive converter because each rotor winding is connected in series with converter switching elements. 2002 by CRC Press LLC Bidirectional currents are not necessary which facilitates the reduction of the number of power switches in certain applications. The bulk of the
