The permanent magnet assisted synchronous reluctance machine (PMASynRM) owns high torque density and high efficiency. However, the relatively high torque ripple restricts its application. In this paper, a novel rotor topology is proposed to reduce the torque ripple for the PMASynRM. The rotor is composed of two sets of stacks whose flux barriers have mirror symmetry. The analytical model is proposed, based on which the relationship between the torque harmonic of each order and the flux barrier end angles is built. Then the flux barrier end angles are optimized to minimize the torque ripple of the combined rotor. Finally, the results are validated through Finite Element Analysis (FEA) which prove the effectiveness of the proposed method.

In the last decade, the trend toward higher efficiency and higher torque density electrical machines (EMs) without permanent magnets (PMs) for the industrial sector has rapidly increased. This work discusses the latest research and industrial advancements in synchronous reluctance machines (SynRMs), being the emergent motor topology gaining wide acceptance by many industries. This article presents an extensive literature review covering the background and evolvement of SynRM, including the most recent developments. Nowadays, SynRM has found its niche in the EM market, and the reasons for that are highlighted in this work together with its advantages and disadvantages. The key journal publications in SynRM topics are discussed presenting the biggest challenges and the latest advancements with particular regards to the design methodology. This article aims to provide a thorough overview to the research community and industry about SynRM. There is a clear potential for SynRM to take over a significant portion of the EM market in the near future to meet efficiency standards in industrial applications without the use of rare-Earth PM technology.

This paper presents a comparative study on traction motors built using random and hairpin winding. Advantages and disadvantages of each winding configuration are reported and challenges of using hairpin winding are detailed. The paper focus is placed on winding copper loss, which is the main root of performance differences in motor equipped by random and hairpin windings. A motor is designed using both winding types. Differences in losses and their effect on motor efficiency is studied. Considering the higher slot fill factor of hairpin winding, DC component of copper losses in hairpin winding has less contribution on the motor efficiency, however, higher AC copper loss is seen in hairpin windings. Thus, motors designed and manufactured using hairpin winding have higher efficiency in comparison to the equivalent random wound motors, especially at high load and low speed.

In the paper bonded magnets materials, their realization and adoption in electromechanical devices, are presented and evaluated. In particular the effects of different process parameters in their realization are deeply analyzed and described, supported by practical activities. Bonded magnets have been tested in various prototypes of rotating electrical machines and magnetic sensors; experimental results, comparing the performance of the devices equipped with these materials, with the original ones are presented. Furthermore a new magnetic material family is being explored, the Hybrid Magnetic Composites (HMC); they are prepared with both soft and hard magnetic powders, properly mixed with binders, and some examples of adoption in practical applications are proposed.

This paper presents an extensive study on the electromagnetic and structural influences of the end barrier shape of a Synchronous Reluctance Machine (SynRel). One of the most challenging tasks in designing these machines is to achieve a smooth torque and a mechanically robust structure, especially when high operating speed range is required. Several papers have already addressed the electromagnetic design problem related to the choice of the flux barriers thicknesses and positions. However a comprehensive work on the influence of the end part of the flux barrier on the electromagnetic and structural performance has not been yet presented. In this work two end barrier shapes are considered and optimized using the same methodology. Then the optimized machines have been deeply analyzed in terms of torque, torque ripple and rotor von Mises stress distribution. Furthermore, with the aim to further investigate the influence of such end barrier shape, a detailed sensitivity analysis is presented. In conclusion, general guidelines for the structural and electromagnetic design of such end barrier shape are drawn.

The variation of the self-sensing capability of different type of electrical machines due to parasitic effects is considered in this papers. Thanks to a specific simulation strategy the variations of the machine saliency and the error angle are computed considering different rotor positions and different working points. It is shown that a large variation occurs in particular working points. The presented approach is useful during the design process of the machine in order to assess the self-sensing capability of the machine and its impact on the control scheme adopted in the drive.

An analysis of the magnetic behavior of different slot geometries is proposed by means of finite element (FE) software. An intentionally created anisotropy is introduced in the rotor bar geometry, so as to allows a sensorless detection of the IM rotor position. The proposed FE procedure allows to evaluate the sensorless control capability of the IM. The parameters of the induction motor (IM) are determined by means of a FE procedure, based on the d- and q- axis model of the machine. Such a procedure is quite rapid, since is based on the time harmonic response to a high frequency injected signal in the stator winding. This procedure is used to predict the variation of the IM parameters and it results to be useful for both analysis of the IM performance and the design step of the machine. A rotor geometry with an intentionally created magnetic saliency have been analyzed. The rotor prototype is under construction, in order to verify the predicted results.