Vol.:(0123456789) 1 3 Journal of Electrical Engineering & Technology https://doi.org/10.1007/s42835-020-00493-8 ORIGINAL ARTICLE Torque Ripple Analysis of Synchronous Reluctance Motor with Diferent Rotor Topologies for Application with Dimensional Constraint M. A. H. Rasid 1  · Vincent Lanfranchi 2  · Alejandro Ospina 2  · Khadija El Kadri Benkara 2 Received: 28 January 2020 / Revised: 24 June 2020 / Accepted: 20 July 2020 © The Korean Institute of Electrical Engineers 2020 Abstract Synchronous reluctance machine (SynRM) is reemerging as a thermally robust and inexpensive actuator solution mainly due to the lack of permanent magnet. Added to that, the possibilities of having diferent rotor topologies make it very versatile where further optimization is possible depending on the objective, be it cost, ease of fabrication, power output, or torque quality. In an application where the outer dimension of the motor is strictly limited, this paper compares quantitatively and qualitatively the torque ripple of three SynRM machines of the same stator dimension equipped with diferent rotor topolo- gies: segmented, tooth and fux barrier. Using an experimentally validated FE model, the torque ripple and the ripple’s harmonic content are compared at maximum load (stator current, I S = 50 A) and load angle (β = π/4). The machine adopting the fux-barrier rotor was shown to have the best torque quality (41% ripple), followed by tooth rotor (78% ripple) and fnally segmented rotor (105% ripple). The harmonic contents are also presented and analyzed. Keywords SynRM machine · Torque ripple · Rotor topology · Segmented rotor · Flux-barrier rotor · Solid rotor · Harmonic contents 1 Introduction The ongoing electrifcation in all applications has pushed the design of electrical machines to a new level. Regular and traditional induction machines and other Brushless and DC motor are insufcient. All topologies are being rediscovered and studied and optimized to satisfy diferent needs of difer- ent applications. Synchronous reluctance machine (SynRM) which is a category of variable reluctance machine is one of them. It has been a motor with great strength regarding thermal robustness. SynRM with a passive rotor has a large advantage, having a minimum heat source and easy heat evacuation (due to the location of winding on stator solely) [1–5]. 1.1 SynRM Rotor Topology Another very strong advantage is that it has numerous dif- ferent topologies of rotor that can be adopted. SynRM is therefore very versatile where further optimization is largely possible depending on the objective, be it cost, ease of fabri- cation, power output, or torque quality. There are four major categories of rotor: tooth rotor, segmented rotor, fux-barrier rotor, and axiallylaminated rotor (Fig. 1). Tooth rotor is the simplest and the most elementary form of variable reluctance rotor. It is usually constructed as a tooth massive piece, hold by a shaft. Its design has a simple and rigid structure but a low saliency ratio especially for a small size motor and consequently poor performance due to high quadrature permeance. However, the rigid struc- ture creates the possibility of using it in high-speed [6] and extremely high-speed machines [7]. Diferent variations of construction to maximize the saliency ratio while retain- ing its structural advantage can be found [8]: classic tooth, drilled and slit are among them [9]. As for saliency ratio, Chiba in [10] has reported a saliency ratio of about 2.5 for a two-pole motor while Hassan has reported a higher saliency ratio, but not more than 3.8 in [11]. * M. A. H. Rasid mahizami@ump.edu.my 1 Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, 26600 Pekan, Pahang, Malaysia 2 CNRS, FRE 2012 Roberval, Universite de Technologie de Compiegne, 60203 Compiègne, France