Torque calculation of five-phase synchronous reluctance motors with shifted-asymmetrical-salient-poles under saturation condition

Abstract

In traditional analytical method (AM), the magnetic saturation is always ignored to simplify the calculation process. However, synchronous reluctance motors (SynRMs) often operate around saturation point to achieve higher torque density. Therefore, a new AM is proposed, in which the saturation of stator iron has been considered. The key of the proposed method includes a saturation factor, and an iterative method is adopted to compute the saturation factor in the SynRM by increasing the air-gap length. Especially, the proposed AM can be applied to a SynRM even with shifted-asymmetrical-salient-poles. In the process of AM, the expression of stator magnetomotive force (MMF) is built firstly. Additionally, the air-gap density including slotting effect and salient-poles is calculated. Then, the rotor MMF under saturation of the stator iron is obtained. Therefore, the precision of the instantaneous torque can be improved significantly. Eventually, by the verification of finite elements method (FEM) and experiments, the torque performance of SynRMs with shifted asymmetrical rotor can be predicted accurately by the proposed AM.

A Review on Additive Manufacturing Possibilities for Electrical Machines

“…Research work to exploit alternative asymmetrical/non-conventional machine designs is under process by various researchers. Design examples such as those presented in [82][83][84][85][86][87][88][89][90][91] highlight the benefits of introducing asymmetry based on; unity motor asymmetry concept, repositioning of slot openings per-pole-per-phase, altering position of embedded bars on adjacent rotor poles and asymmetrical rotor configuration. Figure 9 presents pictorial representation for such examples and Table 1 showcases various benefits achieved from introduction of asymmetry in design.…”

Utility and Application of a Versatile Analytical Method for MMF Calculation in AC Machines

“…Although this theory shares similarities with the magnetic field modulation theory [14] or other analytical modeling methods [15], in terms of calculating MMF and torque, including the application of winding theories and Fourier series analysis, it addresses a distinct problem domain. Magnetic field modulation theory or other existing methods primarily focuses on the methodology for accurately modeling the source-modulator-filter system and places greater emphasis on the modulation and saturation effects of motor mechanical structures on the air-gap magnetic field.…”

Simulation of Indirect Field Oriented Control on 5-Phase Synchronous Reluctance Motor

“…These issues can be overcome by properly manipulating the design parameters of SynRM or by proposing a suitable control technique [4]. Besides, increasing the number of SynRM phases to reduce the undesired increase in the torque ripple is considered an effective way [10], [11].…”