Synthesis of high performance PM motors with concentrated windings

Abstract

The windings concentrated around the teeth offer obvious advantages for the electric machines with radial air-gap, because the volume of copper used in the end-windings can be reduced. The Joule losses are decreased and the efficiency is improved. These machines are still limited to applications of subfractional power and they generally present a reduced number of phases. In the three-phase machines, the concentrated winding is too often restricted to a winding with a short pitch of 120 electric degrees, i.e. to a winding with performances reduced compared to the traditional structures. But there is a significant number of three-phase structures which can support a concentrated winding if the number of poles is increased. In this article, the author present a synthesis of the structures of three-phase machines with concentrated windings. In the first part, the structures with a regular distribution of the slots are presented. A systematic method is proposed to determine the windings and the performances are discussed. In the second part, the authors present original structures of three-phase machines with concentrated windings which use an irregular distribution of the slots. A specific method to identify these structures is described and a comparative analysis of the performances of the original and traditional structures is performed by using a field calculation software.

Investigation of a Novel 24-Slot/14-Pole Six-Phase Fault-Tolerant Modular Permanent-Magnet In-Wheel Motor for Electric Vehicles

“…Additionally, some references have already focused on concentrated winding machines using an irregular distribution of the slots [33][34][35]. Even though the irregular distribution of the slots is, essentially, the unequal teeth scheme, it can still be distinguished from what is talking in this article.…”

“…Even though the irregular distribution of the slots is, essentially, the unequal teeth scheme, it can still be distinguished from what is talking in this article. What is concerned in references [33][34][35] is how the irregular distribution of the slots is derived from a conventional distributed winding step by step. Besides, high performances-reduced copper loss, low torque ripple and enhanced output torque-was obtained by employing the structure of irregular slot distribution.…”

Multi-criteria-based design approach of multi-phase permanent magnet low-speed synchronous machines

“…In this paper, the procedure to determine a convenient 5-phase winding is deduced from [15]. If the phase number, the pole number and the phase number are known, it is possible to deduce a set of coils per phase that leads to balanced multi-phase windings.…”

Comparative Analysis of Partitioned Stator Flux Reversal PM Machine and Magnetically Geared Machine Operating in Stator-PM and Rotor-PM Modes

“…According to the PM locations, PM machines can be classified into two types [3], i.e. the rotor-PM machines having rotating PMs [4]- [7], and the stator-PM machines in which PMs are static in the stator.…”