The synchronous reluctance machines with transversally laminated rotor and multi flux-barriers per pole reach a high torque density, so that they are proposed as a valid alternative to permanent magnet machines. Such machines have been analyzed for different applications, mainly home appliance, industrial tool, traction, up to low-speed high-power generators. On the contrary, the use of synchronous reluctance machines for high-speed applications remains almost unexplored yet. The aim of this paper is to investigate the potential of a high-speed synchronous reluctance machine. An optimization is carried out to maximize the machine performance at a given speed. The machine size is fixed and the focus is on the rotor geometry, with the purpose of maximizing the electromagnetic torque, according to the necessary thickness of the ribs. It is shown that, even if the ribs are thick, it is possible to reach a proper torque density. It is shown that different solutions exist, which allow to reach high torque and minimum torque ripple. However, the optimal solutions are quite sensitive to the geometrical variations, so that a particular care is required in the manufacturing of the machine. Finally, the power limit of the synchronous reluctance motor with barrier rotor is found.

This article compares the characteristics of a dual three-phase synchronous motor under different operating conditions such as healthy, half-control, and postfault conditions. The inductances are analyzed to confirm the interaction between two three-phase systems, and induced voltages of each phase are measured to verify the interaction behaviors. The postfault characteristics are analyzed under open-circuit faults (single-open-switch and single-open-phase faults) and short-circuit faults (single-short-switch and one-three-phase-short faults). The predicted results are validated by experimental tests. Moreover, the half-control mode is investigated as a strategy to operate with high efficiency and tolerant mode.

The aim of this paper is to tackle the design of synchronous reluctance machines with transverse laminated rotor for high-speed applications by means of an analytical model. In high-speed applications, the mechanical design greatly affects the motor performance in terms of torque density and power factor. In fact, as the rated speed increases, the radial ribs thicknesses increase as well to ensure the rotor structural integrity against the centrifugal force. This increases the quadrature flux and therefore the rotor anisotropy gets worse. Hence, the optimal rotor design is the result of a compromise between mechanical and magnetic aspects. The purpose of this paper is twofold: (i) to develop an analytical model that links the maximum average torque to the rated speed and (ii) to determine the maximum power that can be generated by a specific rotor geometry. The analytical approach allows a fast motor design and analysis so that a rapid extrapolation of the results to different machine size is possible. Finite element analysis is used only to validate the final results.

This study presents two design methodologies for high‐speed synchronous reluctance (REL) machines. The interest for high‐speed drives comes from the request for compactness and high efficiency. The synchronous REL motors have been widely studied for several applications, but a coherent design procedure for high speed has not been proposed in the literature. The study proposes some analytical procedures to get an initial design. Then the rotor geometry optimisation through a differential evolution algorithm is described. Finally, a design example is given and thoroughly analysed using these two approaches.

In high speed systems, the recent trend is to couple the electric machine directly to the mechanical shaft, in order to avoid the use of a gear-box and to increase the overall efficiency and reliability. Surface Permanent Magnet mounted (SPM) machines are usually adopted in such systems for their high torque density thanks to rare-earth PMs. The cost of rare-earth PMs together with the risk of their demagnetization induces to consider other alternatives such as the Synchronous Reluctance (REL) machine. The design of REL machines for high speed applications has to be carried out considering both magnetic and mechanical aspects. In particular, the iron ribs must be accurately designed with the aim of achieving the minimum flux leakage in the ribs and ensuring the structural integrity. The present paper deals with the design and comparison of an SPM and a REL motors with fixed stator geometry and winding. Such an approach allows to investigate the potential of the synchronous reluctance machine in comparison to the SPM one. It is shown that the synchronous reluctance machine represents an interesting alternative to SPM machines for its low cost and insignificant susceptibility to demagnetization. In fact the lower torque density achieved by the reluctance motor can be compensated with a limited increase of the stack length or with a higher electric loading.

The design of synchronous reluctance machines for high-speed applications is an issue that nowadays remains almost not dealt with. The thickness of the iron ribs that mechanically sustain the structure increases with the rotor speed, so that a high magnetic flux flows through them. Therefore, the available torque decreases with the rated speed required by the application. The aim of this paper is to tackle the design of synchronous reluctance machines for high-speed applications. The potentials of a high-speed synchronous reluctance machine are investigated. For a given operating speed, the mechanical structure is firstly designed, so as to achieve a robust rotor. Then the maximum torque is investigated according to the thermal limits. A tradeoff between increasing speed and decreasing torque is obtained, up to obtain an optimum value of the electromagnetic power. An advantage of the proposed procedure is its analytical nature: all the design steps are based on analytical relationships, so as to allow a rapid extrapolation of the obtained results to different machine size, operating requirements, and so forth. Finite element analysis is used only to validate the final results.