A new technique for optimum excitation of switched reluctance motor drives over a wide speed range

Abstract

Optimum performance of switched reluctance motors (SRMs) over a wide range of speed control is an essentialapproach for many industrial applications. However, the doubly salient structure and deep magnetic saturation makemagnetization characteristics of SRMs a highly nonlinear function of rotor position and current magnitude. This, in turn,makes the control of SRM drives a challenging task. As the control of SRMs depends on the inductance profile, it requiresan adaptive control technique for optimum operation over a wide range of operating speeds. This paper presents anadaptive control technique for optimum excitation of SRM drives. The proposed control technique accurately considersthe effect of back-emf voltage for high- and even low-speed operation. It determines the most efficient switch-on angleas a function of motor speed and current magnitude. Moreover, the optimum switch-off angle is defined to enhancemotor output torque/power without negative torque production. The proposed technique simplifies the SRM controlin order to cut down the complexity and cost; it offers easy implementation and can be used for sensor and sensorlessoperation of SRM drives. It also provides an eligible candidate for industrial applications as the optimization strategyuses an analytical solution. For adequate modeling, the nonlinear magnetization characteristics of the SRM are obtainedusing finite element analysis. The SRM, converter, and control algorithm are modeled using the MATLAB/Simulinkenvironment. The simulation results are compared with a closed-loop switch-on angle controller in order to show thefeasibility of the proposed control technique. In addition, experimental results are obtained to prove the promisingperformance and simplicity of the proposed controller.