Control of Switched Reluctance Machines
Switched reluctance motors (SRM) differs from most machine topologies in their unique geometry and torque production mechanism, which results in challenges in modeling the motor. The machine’s doubly salient structure creates large variations in the air gap, which means that the machine flux linkage is a nonlinear function of rotor position. When the machine geometry is defined, the shape of the air gap determines the inductance profile, which will have an effect on the machine’s dynamic behavior. Due to the doubly salient structure, this inductance profile varies with position, which has a significant impact on torque production. The heart of the control scheme for SRM is current control, in which the phase current is shaped based on a series of predetermined parameters in order to meet different objectives for speed, torque, power, and efficiency across a wide range of operating conditions.