A New PM-Assisted Synchronous Reluctance Machine with a Nonconventional Fractional Slot per Pole Combination

Abstract

Fractional-slot concentrated-winding synchronous permanent magnet machines (PM) are appreciated for their simple construction and high torque density. Unfortunately, it is well known that such fractional slot / pole combinations kill the reluctance torque potential of salient interior PM rotor configurations. To date, this has hindered the application of fractional windings to machines of the Synchronous Reluctance and PM-assisted Synchronous Reluctance types. This paper proposes a new fractional slot PM-assisted Synchronous Reluctance machine with 24 slots and 10 rotor poles. The new machine is compared to a benchmark 10-pole PM-assisted machine having 90 slots and distributed windings and to another competitor with 12 slots concentrated windings. FEA results show that the new machine is comparable to the distributed windings version in terms of torque density and losses, and much easier to be manufactured.