State-Switching Control Technique for Switched Reluctance Motor Drives: Theory and Implementation

Switched reluctance motors (SRMs) exhibit advantageous features such as low inertia, fault tolerance, high efficiency, and simple design. However, its control is fairly complex due to nonlinear characteristics of the magnetic flux linkage seen on the stator windings. Several memory and/or processor intensive solutions have been proposed to deal with the control problem, constraining the use of the motor to high-cost and high-performance applications. The focus of this paper is to develop a simple controller for the SRM based on state-switching digital control. The concept of state-switching digital control is to control the motor state (speed) by applying a high or a low energy pulse-above and below the desired steady state of the motor. Such a controller can be implemented in low-complexity analog circuitry. This paper presents two methods of motor control: one for single-speed applications and another for variable speed applications. In addition, this paper derives the control equations and disturbance rejection response. Simulation and experimental results for various operating modes are presented.