Magnet design and motor performances of a double-layer interior permanent magnet synchronous motor

In this paper we discuss the results of our investigation of the interior permanent magnet synchronous motor (IPM), with permanent magnets embedded in the rotor, and particularly the double-layer IPM synchronous motor, which has two layers of magnets embedded in the rotor, layered in the radial direction. For this investigation, we studied the arrangement of permanent magnets both through simulation and by experiments with a prototype. The results concerning the form of the magnets clearly show the advantages of the reverse are configuration, which makes it possible to increase the surface area creating magnetic flux. We further determined that to maximize both the q-axis flux and the flux of the permanent magnets, the optimum width of the q-axis flux path between the magnets for the motor investigated here is 2 mm. The results also clearly show that chamfering the ends of magnets is effective in achieving better utilization of the q-axis flux. (C) 1999 Scripta Technica.