This paper presents the results of an investigation into the end-effect in Interior Permanent Magnet Synchronous Motors (IPMSM) with rare-earth magnets. The 6-slot/4-pole concentrated winding machine with different stack length and permanent magnet arrangement is used in this study. The analysis shows that the end-effect decreases the normalized magnet torque productivity and increases the resistance to demagnetization as the stack length decreases. The latter indicates that thinner stack length provides higher electric loading for the given demagnetizing factor and, therefore, higher torque density can be expected. Another important point is that an increase in embedded depth of permanent magnet raises the end-effect impact. From these results, to have a higher torque density, the ultra-thin IPMSM with deeply embedded PM type rotor is preferred.
