Comparison of different synchronous machines with stator-side permanent magnets for industrial drive application

Three different synchronous machines with the permanent magnets in the stator (doubly salient permanent magnet, flux reversal permanent magnet, and flux switching permanent magnet machine) are compared for use as an industrial drive for 45kW, 400V Y, and 1000 .... 3000min(-1). For comparison, finite element method simulations are carried out to investigate the torque density of the machines, and the results are explained based on the magnetic co-energy. The simulations show that the flux switching machine generates the highest torque density of the three machines. Therefore, a prototype flux switching machine is built, tested, and compared with a conventional permanent magnet synchronous machine (PMSM) with magnets on the rotor surface, the same size (stator outer diameter d(so)=314mm, axial length l(Fe)=180mm) and rating. The measurements indicate that the conventional PMSM and the flux switching machine have roughly equivalent electrical behaviour.