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A hybrid ferrite‐Al‐Ni‐Co permanent magnet assisted synchronous reluctance motor (PMa‐SyRM) for an air‐conditioner compressor is proposed. Al‐Ni‐Co PMs have high residual flux density similar to rare‐earth PMs such as Nd‐Fe‐B and Sm‐Co. Therefore, the performance parameters of the PMa‐SyRM such as power factor, efficiency etc., with Al‐Ni‐Co PMs can be improved without significantly increasing the cost of the motor. However, Al‐Ni‐Co PMs have a steep IInd‐quadrant B‐H curve, and the challenge lies in addressing their demagnetisation issues. In the proposed hybrid PMa‐SyRM, the rotor geometry is suitably optimised for placing the Al‐Ni‐Co PMs in the centre flux barriers to address the demagnetisation issues. Further, an analytical magnetic circuit is presented to design the proposed PMa‐SyRM. Later, 2‐D finite element analysis of the proposed motor including the demagnetisation analysis of PMs and stress analysis of the rotor is carried out and presented. A prototype is fabricated, experimental validation is carried out, and the results of the performance and cost are compared with that of ferrite and hybrid ferrite‐Nd‐Fe‐B PMa‐SyRM. [ABSTRACT FROM AUTHOR]

The authors present a new design of a PM‐assisted synchronous reluctance motor (PM‐SynRM) with uneven air‐gap length to improve the power factor and enhance the torque production capability. The rotor structure is modified to properly shift rotor magnetic poles and therefore (i) increases the back‐EMF and the electromagnetic torque, (ii) allows electromagnetic torque and reluctance torque components peak near the same current phase angle. The proposed solution is simple, does not require changing the arrangement of magnets and/or flux barriers and is applicable to all types of PM‐SynRMs. Sensitivity analysis is carried out to determine the extent of which the proposed magnetic pole shifting may impact the resultant torque profile. To assess the level of success, the electromagnetic characteristics of the proposed design (e.g. torque, power factor, and back‐EMF) are compared against the baseline structure under the same operating conditions. For verification purposes, Finite Element simulation results are validated via a series of analytical calculations and experimental measurements, and supported with detailed theoretical discussion. [ABSTRACT FROM AUTHOR]

This paper describes a procedure for a practical synthesis of both a synchronous reluctance motor and a permanent magnet assisted synchronous reluctance motor. The procedure is completely analytical, yielding a rapid drawing of the motor geometry, taking into account both magnetic and mechanical considerations. From the application requirements, the external volume of the motor is computed. The further practical needs, such as maximum outer space, maximum available length, existing stator lamination, and so on are considered. Then, the design of the rotor geometry is carried out. The PM size is determined considering the demagnetisation limit according to the maximum current loading. [ABSTRACT FROM AUTHOR]

This paper presents the comparison of three-phase and five-phase permanent magnet assisted synchronous reluctance motors (PMa-SynRM) in terms of their design and performance characteristics. With higher fault tolerant capability, efficiency, and reliability, the five-phase PMa-SynRM can be a better substitute when compared with the three-phase PMa-SynRM in critical applications where safety is top priority. In this study, for a fair comparison, same design procedure using in lumped parameter modelling is followed in developing the three-phase and five-phase PMa-SynRMs. The models are optimised to minimise cost and maximise efficiency. For further detailed comparison of the three-phase and five-phase PMa-SynRMs, two-dimensional finite element analysis (FEA) is utilised. Performance characteristics such as torque pulsation, back electromotive force, flux linkage, d- and q-axis inductances versus their respective currents, cogging torque, efficiency plot, and torque-speed characteristics are intensively simulated through FEA. The optimised three-phase and five-phase PMa-SynRMs are fabricated with the same power rating (3 kW) and same volume. Experimental tests are conducted on the prototypes to validate the simulation resu lts. [ABSTRACT FROM AUTHOR]

This paper presents a multi-physic analytical model for a permanent magnet assisted synchronous reluctance motor. The proposed model consists of: an electromagnetic model, an electrical model, a loss model, and a thermal model. The electromagnetic model is based on Maxwell's equations. Stator and rotor magnetic saturation is considered, as well as the effect of the magnetic bridges of the flux-barriers. The electrical model computes the terminal voltage and power factor. Copper loss and iron losses are also considered. The thermal model makes an estimation of the winding and magnet temperature. The goal is to compute the motor performances (average torque, voltage, power factor, efficiency etc.) for several current values and current angles. The analytical model results are compared with those from a finite element model and are subsequently validated by an experimental prototype. [ABSTRACT FROM AUTHOR]