This study presents a comprehensive analytical analysis of line start permanent magnet (LSPM) synchronous motors in both steady-state and transient domains. The PM flux, the back-EMF and the winding inductances are first calculated in the steady-state based on the hybrid solution of magnetic circuit and the magnetic islands. Next, the motor voltage relations are mapped into an arbitrary d-q reference frame to dynamically assess the transient speed response as well as the individual motor torque components. Based on the presented analytical modelling, the parameters of the motor are optimised via genetic algorithm to maximise the back-EMF voltage and the overall steady-state performance. Given the parabolic relation between the back-EMF and the braking torque, the starting capability of the motor is defined as the optimisation constraint. Finally, the analytical results are verified by using a finite element analysis software package.

No abstract

An analytical model is proposed for the prediction of the no-load air gap magnetic flux density and the armature reaction in the slotless surface-inset PM machines. For this purpose, the exact 2D solution of the Poisson equation is derived. In the modelling process, the rotor salient poles are taken away and some surface magnetisation currents are considered at the borders of the removed salient poles. The contribution of this work is finding the value of the surface magnetisation currents such that the rotor saliency is accurately considered. The field solution in the provided surfacemounted PM machine is simply obtained by the separation of variables method. The machine back-EMF and its inductances is obtained by the predicted flux density due to the PMs and the stator currents, respectively. In addition, using the resultant air gap flux density in the Maxwell stress tensor, the developed electromagnetic torque is computed. Finally, the ability of the proposed model is evaluated by finite element analysis as well as experimental tests.

No abstract

No abstract