Modelling of Switched Reluctance Machines: State of the Art

Abstract

This article gives an overview of different modelling techniques to describe the nonlinear behaviour of both saturated switched reluctance machine (SRM) and power electronic converter. The current research contributes by comparing the decoupled singlephase superposition method (lookup-tables) with a coupled analysis between drive model in Matlab/Simulink® and finite element model of the SRM motor in Flux2D®. Experimental characterization techniques as well as finite element techniques are used to obtain the single-phase flux-linkage data. Transient electromagnetic analysis using the finite element method, coupled with a drive model and optimization strategy in Matlab/Simulink®, results in a more accurate SRM modelling. These results are more accurate because the mutual coupling between different phases is taken into account. Using this direct coupling, we can model a complete analysis of the motor behaviour (local saturation, iron losses, etc.) with the finite element software, keeping the complex drive and control strategy in Matlab /Simulink®. At every time-step of the discrete solver, data are exchanged between the drive model and the coupled electric circuit of the finite element analysis. Simulation results are compared with measurements of flux-linkage, torque, phase current, and iron losses. Advantages and disadvantages of the coupled and decoupled modelling technique are discussed.

Linear Switched Reluctance Motors

“…In order to overcome that handicap, it used a 2D-FEA adjusted in accordance with the end-effects. The end-effects in 2D FEA are considered by means of the end-effects coefficient, K ee [16], given by:…”

“…where Ψ 2D and L 2D are the flux linkage and the inductance obtained by 2D-FEA; and Ψ 3D and L 3D are the 3D flux linkage and the inductance approach that account for the end-effects and are closer to the measured values. The correction factor K ee is defined as [16,17]…”

Modelling and simulation of a linear switched reluctance force actuator

“…The most accurate way to estimate the end‐effects is probably by means of 3D FEA, but it still takes great computing time compared with 2D FEA. In order to deal with the end‐effects and maintain computer time as low as possible, correction factor ( K ee ) for 2D flux linkage is used (11), which depends on the current ( i ) or current density ( J ), and position ( x ) [12]. This factor accounts for the end‐effects and gives good estimation of 3D flux linkage.The correction factor K ee is defined aswhere L end is end‐winding inductance and K f is axial fringing factor [17].…”

“…This dynamic model is executed by means of ‘Matlab‐Simulink ® ’ environment coupled with finite element analysis (FEA) and then implemented in a ‘DSPACE ACE kit 1006 CLP’ that includes a processor board with an AMD Opteron TM running at 2.6 GHz. Up to now, many papers have dealt with modelling and simulation of rotating switched reluctance motor drives, as a sample [12, 13], and of their linear counterpart [14, 15], all of them emphasise the importance of determination of magnetisation curves. In this paper, special attention is given to determination of magnetisation curves, using different procedures and introducing a 2D FEA corrected in order to take into account end‐winding effects.…”