Magnetic modelling and sensorless control of the synchronous reluctance machine

This thesis is essentially divided into three major sections. The first section involves the development of a model of the Synchronous Reluctance Machine (SyncRM) that enables the estimation of fluxes and flux densities in various parts of the motor. The technique develops a model that recognises the zigzag nature of the rotor flux. T h e results obtained from the analytical modelling are compared to those obtained from a finite element analysis of the same machine. The second section develops a new sensorless position estimation algorithm. It is based on a parameter independent statistical method. The technique makes use of the observation that the current changes are statistically more likely to be higher in the q-axis rather than the d-axis of the SyncRM. The parameter independence is demonstrated by a detailed simulation which uses a design that has a very low saliency and is still able to produce quality results. The principle is proven using the detailed simulation. The algorithm is extended to produce a speed estimation signal by the use of a modified zero crossing algorithm. The third section of the thesis involves verification of the sensorless algorithms developed. A 22-kW, 6 pole, axially laminated S y n c R M and an inverter system is used to verify the new sensorless techniques. Extensive experimental results are presented that confirm the excellent performance of the algorithms.