Frequency-Geometric Identification of Magnetization Characteristics of Switched Reluctance Machine

Abstract

Accurate modeling of electrical drives for online testing is a relevant problem. Switched Reluctance Machine (SRM) has lately attracted significant attention because it has several advantages compared to conventional engines. It is simple, free of rare-earth and fault-tolerant machine. An analytical model of a SRM has not been reported yet due to the dynamic and strong nonlinearity of SRM. The most SRM control and applications are based on several assumptions and simplifications. Therefore, it is convenient to develop an accurate approach to identify the SRM characteristics. In this paper, an analytical modeling and identification method of magnetization characteristics of Switched Reluctance Machine (SRM) is proposed. Presently, an exact mathematical model of SRM is established. Unlike several previous studies, in this approach the system nonlinearities of SRM are allowed to be hysteresis (i.e. the hysteresis effect is considered) and taking account the inherent magnetic nonlinearity. Indeed, the SRM is considered as highly nonlinear which makes the modeling of these machines difficult to achieve. Then, it is convenient to develop an accuracy model of SRM because it is always operated in the magnetically saturated mode to maximize the energy transfer. The developed model can be used in control, simulation and design development. Furthermore, an identification method, at standstill test, based on frequency technics is developed allowing the identification of SRM nonlinearities (considering the saturation and the hysteresis effects). In this respect, it is shown that the nonlinear behavior of SRM can be exactly described by a block-oriented nonlinear structure. Specifically, the SRM can be described by a Wiener nonlinear model. Compared to the existing methods, the proposed study gives good accuracy of flux-linkage value characteristics and enjoys the simplicity of implementation.