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The purpose of this paper is to present the optimal design of a low-cost interior permanent magnet (IPM) alternating current (AC) motor. It examines the influence of the permanent magnet (PM) materials, and proposes a simple and practical method of optimizing the air-gap field to achieve sinusoidal back electromotive force (EMF), and to reduce the cogging torque.

IPM AC motors with different magnet materials and various topologies are comparatively studied. Finite element method (FEM) is used to predict the performances of these designs. Material costs and manufacture costs are both taken into account. Finally, an optimized design is prototyped and tested, validating the design considerations.

In an IPM AC motor, even if the rotor outer profile is round, the air-gap field distribution can be fined, while the cogging torque can be significantly reduced, by properly shaping the stator tooth tips. Nevertheless, this technique is usually applicable to motor configurations with concentrated windings, but not to those with distributed windings.

While using ferrite magnets for PM AC motors with a kW power, interior magnets are usually inserted in V-shaped slots, and the rotor outer profile is often shaped in order to enhance the air-gap field distribution. However, such a rotor configuration usually increases the manufacture costs, and also deteriorates the consistency of mass production. Therefore, a new motor configuration with a round rotor outer profile and shaped stator tooth tips is proposed. It can not only overcome the aforementioned problems, but also improve the motor performance.

Aims to investigate the eddy current loss in permanent magnets of IPM motors.

Uses the 3D finite element method (3D FEM).

Finds that the effect of the current phase on the eddy current loss is very different according to the number of slots.

Investigates the eddy current loss in a permanent magnet of an IPM motor.

The purpose of this paper is to include thermal analysis in the design process of permanent magnet synchronous motor (PMSM). The additional objective is a comparison of PMSM with induction motor (IM) in terms of thermal phenomena.

Numerical investigation using commercial software MotorSolve was performed. Parameterized models of PMSM and IM were used. Calculations of motor parameters and temperature distribution were made using Finite Element Method.

The results of the calculations show that thermal calculations should be included in the design process because the maximum permissible operating temperature of permanent magnets should not be exceeded. A comparative analysis of PMSM and IM shows that the PMSM has better parameters than the IM which was used as a base of the PMSM construction.

Computational models should be verified experimentally on a physical model or by using more complex numerical models. In the case of IM thermal calculations, a method of air speed calculation should be proposed. Air speed is a parameter that is necessary in thermal analysis of IM, but during the design process it is unknown.

This paper presents modelling methodology of 3D transient thermal field coupled with electromagnetic field applied in a three-phase IM at rated load conditions. This paper presents a design strategy which includes thermal analysis of the designed PMSM. Moreover, the paper shows a comparison between PMSM and IM indicating advantages of PMSM over IM.

Describes the method of optimization based on the finite element method. The quality engineering and the multivariable analysis are used as the optimization technique. In addition, this method is applied to a design of IPM motor to reduce the torque ripple.

The aim of this paper is to present a new sensorless control strategy using a flux observer, which is particularly designed for taking into account the rotor saliency and winding inductance variation in an interior permanent magnet synchronous motor (IPMSM).

In a PMSM, the magnets‐excited flux‐linkage, i.e. the rotor flux‐linkage, can be expressed as a vector. Its phase angle stands for the rotor position. Therefore, if this vector is estimated with an observer, the rotor position can be obtained without a position sensor, consequently, sensorless control can be realized. The main object of this paper is to establish and implement a model of rotor flux observer, specifically for IPMSM.

The flux observer model is built on the d‐q‐0 frame, using unequal values of the d‐axis inductance L_d and q‐axis inductance L_q to represent the IPMSM rotor saliency. Its digital implementation is proposed, whilst the sensorless control strategy is experimentally verified.

Insignificant error exists in the estimated rotor position, probably due to the non‐sinusoidal variation of winding inductance. Further improvement of the observer model is preferable.

In previous works, the rotor flux observer is only applied to surface‐mounted permanent magnet synchronous motors (SPMSM) in which the winding inductance is constant. However, the proposed observer can deal with the rotor saliency and inductance variation in IPMSM, whilst its digital implementation is also new.

Recently, considerable attention has been attracted to the development of the new concept motor for EV or HEV. Wider torque and speed controllable operating range and high efficiency under driving area are needed for traction motor. The purpose of this paper is to realize the new concept variable field flux motor with claw pole rotor and brushless robust structure for high-speed range.

In the previous paper, the authors proposed a half-wave rectified brushless variable field flux method with a diode inserted into the field winding. This paper presents a designing for a novel claw pole rotor type motor using the variable field flux method (CP-HVFM). The claw pole type rotor has simple and robust structure for high-speed operation. This paper describes a first prototype design result for CP-HVFM using 3D-FEM. And the authors report the torque and efficiency characteristic results using 3D-FEM.

The authors have studied the designing for CP-HVFM using 3D-FEM. The designed prototype CP-HVFM reached a rated power of 2 kW or more at a rated speed 1,800 rpm under design restrictions of experimental equipment and initial specifications. In addition, the authors found the ratio of the tip and root embrace of the claw pole shape for maximum average torque and minimum torque ripple. Finally, the authors revealed an influence of the armature current on the torque and the efficiency characteristic results for the designed prototype CP-HVFM using 3D-FEM.

The half-wave rectified brushless variable field flux method proved to be effective for the claw pole rotor type motor. And also the authors found the best claw pole shape for torque characteristic. This results are applied to another concept motor for EV or HEV.

Today's brushless permanent magnet (PM) drive systems usually adopt motors including the advancements in magnet technology, e.g. better thermal characteristics and higher magnetic strength. By this means, they become capable in the roughest applications yet maintain a high accuracy at competitive prices. These drive systems are not only appreciated for their high performance, but they are also advantageous for the applications requiring tough, dependable, and continuous‐duty operations, e.g. hybrid or complete electrical vehicles, extruders, wire drawers, winders, cranes, conveyors, and roll formers. The purpose of this paper is to provide an extended comparative study of the different motor configurations for the hybrid electric drive application, aiming at a compromise between high power density and extended speed capability.

To suit strict design requirements, such as the very limited volumetric envelope, high‐output power, wide constant power speed range, and pre‐selected in‐direct cooling system, the constraint variants of possible motor types are researched.

Considerably, high torque density and an extended speed range limit the options of PM rotor configurations for this motor design. The considered rotor configurations are the surface PM (SPM) and interior PM (IPM) types. The advantage of the (non‐salient) SPM configuration is its applicability with higher levels of magnetic flux densities without causing significant saturation in the rotor. On the other hand, an IPM rotor, which places the magnets in special rotor slots, open or closed (by saturation bridges), can operate on both the reluctance torque and the magnet alignment torque. This generally leads to a better performance in a wide speed range. However, this advantage can be eliminated by severe iron saturation resulting from the required high‐specific power.

The most appropriate rotor configuration will finally be selected between the two considered types, depending on detailed electromagnetic and thermal analysis. This paper usefully studies the correlation between the motor parameters required for high power density and field‐weakening performance.

This paper aims to introduce a computationally efficient hybrid analytical–finite element (FE) methodology for loss evaluation in electric vehicle (EV) permanent magnet (PM) traction motor applications. In this class of problems, eddy current losses in PMs and iron laminations constitute an important part of overall drive losses, representing a key design target.

Both surface mounted permanent magnet (SMPM) and double-layer interior permanent magnet (IPM) motor topologies are considered. The PM eddy losses are calculated by using analytical solutions and Fourier harmonic decomposition. The boundary conditions are based on slot opening magnetic field strength tangential component in the air gap in the SMPM topology case, whereas the numerically evaluated normal flux density variation on the surface of the outer PM is implemented in the IPM case. Combined analytical–loss evaluation technique has been verified by comparing its results to a transient magnetodynamic two-dimensional FE model ones.

The proposed loss evaluation technique calculated the total power losses for various operating conditions with low computational cost, illustrating the relative advantages and drawbacks of each motor topology along a typical EV operating cycle. The accuracy of the method was comparable to transient FE loss evaluation models, particularly around nominal speed.

The originality of this paper is based on the development of a fast and accurate PM eddy loss model for both SMPM and IPM motor topologies for traction applications, combining effectively both analytical and FE techniques.

The purpose of this paper is to investigate a new cause of torque ripple in interior permanent magnet (IPM) alternating current (AC) motors, which is common but has hardly been studied. The paper also proposes a new method to suppress the total torque ripple.

Besides the well-known cogging torque and mutual torque ripple, a new ripple which exists in the reluctance torque is found. It is verified with both analytical model and finite element analysis. Also, a novel method is proposed to reduce the reluctance torque ripple, with experimental validation.

It is usually said that the winding inductances of an IPM AC motor vary sinusoidally with the rotor position, thus, the d-axis and q-axis inductances are constant, whilst the reluctance torque is smooth. However, in most practical motors, the inductances vary irregularly, causing a significant ripple in the reluctance torque. Moreover, in machine design, it is always desirable to suppress the cogging torque as much as possible. However, in this paper, it is proved that the cogging torque can remain and be used to cancel the reluctance torque ripple.

Torque ripple in the IPM AC motors is usually reduced by suppressing the cogging torque and making both back electromotive forces and currents sinusoidal. However, this paper reveals the new cause of the torque ripple due to the irregular variation of winding inductances. Moreover, the paper gives a new method to cancel the reluctance torque ripple with the cogging torque.

The purpose of this paper is to apply an Ant colony optimization approach for the solution of the topological design of interior permanent magnet (IPM) machines.

The IPM motor design domain is discretized into a suitable equivalent graph representation and an Ant System (AS) algorithm is employed to achieve an efficient distribution of materials into this graph.

The single-objective problems associated with the maximization of the torque and with the maximization of the shape smoothness of the IPM are investigated. The rotor of the device is discretized into a 9×18 grid in both cases, and three different materials are considered: air, iron and permanent magnet.

The graph representation used enables the solution of topological design problems with an arbitrary number of materials, which is relevant for 2 and 3D problems.

From the numerical experiments, the AS algorithm was able to achieve reasonable shapes and torque values for both design problems. The results show the relevance of the mechanism for multi-domain topology optimization of electromagnetic devices.