Analytical modelling of variable-reluctance machine magnetisation characteristics

The paper presents models that connect the fundamental design of the variable reluctance machine (VRM) to an analytical expression the terminal magnetisation characteristics. The modelling procedure takes simple piecewise linear models which are based on the geometry and turns per phase of the VRM and maps them into an analytic terminal expression through a simple and fast algorithm. The piecewise linear and analytical expressions are based on physical reasoning. The modelling of three existing VRMs is presented, and the model predictions are compared with experiment. Simple models are shown to do an effective job of capturing the spatial and magnetic nonlinearities of the machine, thereby providing useful estimates of net and instantaneous machine performance. The analytic model is shown to compare favourably with another documented approach for the rapid description of VRM magnetisation characteristics