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Due to the increasing demand for high-speed motors with high stability, bearingless motors have attracted much attention. Bearingless permanent magnet synchronous motors (BPMSMs) are a kind of motor, which uses suspension force to eliminate the motor bearings. This article proposes a five-phase BPMSM with 10 slots and 8 poles. Based on the principle of suspension force of BPMSM, an analytical expression of the suspension force is derived for the proposed BPMSM. To improve the suspension stability and torque, an optimization method consisting of a response surface model and a multiobjective optimization algorithm is employed. Not only the geometric parameters but also the winding distribution are considered in the optimization process. Finally, the effectiveness and superiority of the optimal design are verified by experiment.

In this study, we propose a fast topology optimization (TO) method based on a deep neural network (DNN) that predicts the current-dependent motor torque characteristics using its cross-sectional image. The trained DNN is shown to provide the current condition that provides the maximum torque under the assumed motor control method. The proposed method helps perform TO with a reduced number of field computations while maintaining a high search capability.

Este trabajo consiste en el diseño de un modelo de control vectorial (FOC) para el control óptimo de velocidad de un motor sincrónico de imanes permanentes (PMSM) empleando las técnicas de máximo torque por ampere (MTPA) y debilitamiento de Flujo. El proyecto abarcará las fases de simulación y validación del modelo en el entorno Simulink de MATLAB para posteriormente realizar su implementación en una plataforma HIL de prototipado rápido de dSPACE que permitirá realizar el control del motor a través de un inversor de potencia. La solución incluirá una aplicación gráfica diseñada mediante el software ControlDesk para la visualización, control y adquisición de datos en tiempo real que permitirá realizar cambios en los parámetros del modelo, logrando así, emplear las técnicas de HIL para el testeo y validación rápida del diseño. Inicialmente se abordarán de forma general los conceptos técnicos necesarios para desarrollar el modelo del motor PMSM de imanes superficiales, se describirán los componentes de hardware y software empleados para el desarrollo de la solución, para luego construir el modelo mediante los bloques disponibles en Simulink. Se empleará el método de control en cascada, con lazos de control de corriente y velocidad que se sintonizarán mediante la técnica de asignación de polos, buscando que ambos lazos de control tengan una respuesta de un sistema de primer orden, lo cual es ideal para aplicaciones de motores. Posteriormente, en el modelo desarrollado se incluirán los bloques RTI especiales para integración del software con los dispositivos I/O que se conectarán a la caja de control MicroLabBox para el control del motor. Finalmente, se construirá la interfaz gráfica que incluirá los instrumentos para la interacción con el sistema

In this paper, a parallel-series magnetic circuit multi-permanent magnet motor is designed and optimized considering magnet characteristic variation effects, where two kinds of PMs are utilized as co-magnetic. Based on the equivalent magnetic circuit method, the detailed design method for the multi-permanent magnet motor is illustrated. And considering the various operation conditions in potential EV applications, the B-H curves of two PMs of different typical operation conditions are obtained. Then, a multi-objective optimization method is newly proposed which not only focuses on the magnet characteristics variation effect, but also considers output torque, toque ripple as well as anti-demagnetization capability under three typical operation conditions. And the performance of the initial motor and optimal motor are compared under typical operation conditions. Finally, a prototype machine is built and tested. Both theoretical analysis and experimental results verify the validity of the motor and the proposed design optimization method.

This paper deals with the finite element analysis of Hybrid Excitation Permanent Magnet Synchronous Motors, that is, synchronous motors characterised by a rotor including both permanent magnets and an excitation winding. Such a winding is adopted to modulate the rotor flux so that the motor exploits the maximum torque for any operating speed. The higher benefit is obtained at speeds higher than the nominal speed, i.e. during the flux weakening operations. Thus the focus is to determine the flux weakening performance of different topologies of hybrid excitation PM synchronous motors, considering different topologies. In addition, the performance parameters are compared to those achieved with a standard interior PM synchronous motors. The possibility to vary the rotor flux in the hybrid excitation PM motors allows to design the motor with a high no-load flux linkage, necessary to get high torque at low speeds, and to get high torque in a wide speed range.

Powered prosthesis actuation is a field where energy efficiency and mass are important characteristics. The motion requirements of high torque at low speed and low torque at high speed are difficult to effectively combine in a single electric motor. A possibility is to use an oversized direct–drive motor that can deliver the peak torque. However, this results in a heavy actuation system and low overall efficiency. A common practice is combining a smaller electric motor with a gear reduction system. In literature, novel redundant electric actuation systems have been presented with or without locking mechanisms to mitigate this problem. In this work, we provide a comparison of multiple electrical actuation systems composed of electric motors, gear reduction systems and locking mechanisms are compared to each other. This is done using the gait cycle of a human ankle as a case study. An electric motor with a double stator and a single rotor combined with a gearbox shows the most promising overall results when taking energy loss, total mass and complexity of the system into account.

In this article, based on flux modulation theory, an airgap-harmonic-based multilevel optimization design approach is proposed for a double-stator flux-modulated permanent-magnet (DS-FMPM) motor. The proposed DS-FMPM motor is purposefully designed, so as to realize the design requirements of driving cycle. In the proposed optimization approach, based on three fundamental elements of general flux modulation theory, motor optimization design is carried out from three levels. Furthermore, a response surface method, sensitivity analysis, and a genetic algorithm are purposely employed in different levels to obtain optimal motor design. In addition, electromagnetic performances of a DS-FMPM motor are demonstrated in detail. Finally, a prototype motor is manufactured and tested. Both simulation and experimental results verify the feasibility of the DS-FMPM motor and the effectiveness of the proposed airgap-harmonic-based multilevel optimization design approach.

With the large‐scale development of the ball mill, the direct‐drive gearless ball mill has emerged, eliminating the limitation of the transmission torque of large gear. However, it is difficult to process, transport, install and maintain the gearless ball mill because of its vast volume, and the coils cannot be decoupled freely. Therefore, this work proposes a module combined permanent magnet motor with wrapped type for mine ball mill (MBMWT‐MCPMM). Based on the principle of removing coils, the stator is modularized. Each module can be regarded as a small rotary motor, which improves the reliability and fault tolerance of the motor. In this work, the structure and general design process of the MBMWT‐MCPMM are described, and the electromagnetic performance is simulated and analysed. The influence of different factors on the cooling effect of the motor and the temperature rise of different modules during fault‐tolerant operation are analysed. An 80 kW prototype is developed, and its experiments are carried out. The experimental results verify the validity of the related design and analysis.

This work presents the comparative study of the linear tubular permanent magnet motor (LTPMM) for the active suspension system in vehicles. To analyse and design the LTPMM, a finite element‐based optimisation process is proposed. Since the proposed method reconstructs the entire field by storing the information of the air‐gap magnetic flux distribution in the form of a snapshot, it provides high accuracy and a reduced computation time. The magnetic fields are analysed in LTPMMs with external and internal permanent magnets that are classified according to the position of the permanent magnet. In the comparative analysis, an optimal model for the LTPMM is presented, taking into account characteristics such as thrust, detent force and THD. Especially, various magnetisation patterns are considered to accomplish high force density. The analytical model is verified by performing finite element analysis and experiments.

The vibration noise of the distributed drive autonomous ground vehicle (AGV) is mainly produced by the inverter-fed brushless DC permanent magnet in-wheel motor (PMIWM). It is necessary to reduce the vibration noise level of the PMIWM driven by pulse width modulation (PWM). A suppression approach of electromagnetic vibration noise for the PMIWM is investigated. First, the air gap magnetic field of the inverter-fed PMIWM was analyzed. The electric current harmonics and the unbalanced magnetic force (UMF) were investigated. The natural frequency and noise of the PMIWM were presented. Then, a flux-weaken approach was employed to maintain the robustness of the PMIWM when a sudden drop of DC bus voltage. The random switching frequency (RSF) PWM control method based on a two-state Markov chain is proposed to decrease the amplitude of the harmonics caused by the switching frequency and the multiple switching frequencies. The experimental results show that the RSFPWM can not only effectively reduce the vibration noise and the inverter losses, but also improve the robustness of the PMIWM control system under unpredictable uncertainties.

This article proposes the core loss reduction of a surface-mounted permanent magnet motor with a segmented stator core. First, it is shown that the core loss of a motor is decreased by the segmentation of a stator core made of a nonoriented electrical steel sheet. The nonoriented electrical steel sheet used as the segmented stator core has an anisotropy, which is easy to magnetize in the rolling direction. Therefore, it is important to investigate the core loss of the segmented stator core in consideration of the rolling direction of the electrical steel sheet. The rolling direction of the steel sheet can be taken into consideration in magnetic field analysis by using the Enokizono & Soda (E&S) model, which is one of the vector magnetic property utilization techniques. Accordingly, the finite-element method, which introduced the E&S model, is used to evaluate the core loss of the motor. Second, the core loss of the segmented stator core is further reduced by applying a corner radius to each tooth root. Finally, the relation between the core loss and the rolling direction in the segmented stator core applying corner radius is investigated.

Electrical machines are widely used in home appliances, the performance of which is mostly related to the quality function of the electrical machines. What has been used so far in home appliances brought with themselves a wide assortment of advantages and disadvantages. With the aim to overcome the drawbacks of the previously implemented electrical motors in washing machines, a new configuration of flux switching permanent magnet motor (FSPM) with the segmented outer rotor (SOR‐FSPM) is proposed benefitting from a direct driven drum. To reduce the cogging torque as well as torque ripple and to improve the total harmonic distortion, cutting the stator in a way to lower overlapping between the rotor and stator pole, inserting notches into the poles of the rotor to modify the air gap between the stator teeth and the rotor segments are proposed. The Taguchi method and sensitivity analysis are further applied to find the best combination set of changes in such a way to smoothen the chart showing reluctance between stator and rotor and fix the zero‐point crossing of the flux linkages in different rotor positions. Finally, the proposed SOR‐FSPM is prototyped, and experimental results along with the finite element method results are discussed and compared in order to verify the design process.

This paper proposes a novel torque measurement and control technique for cycling-assisted electric bikes (E-bikes) considering various external load conditions. For assisted E-bikes, the electromagnetic torque from the permanent magnet (PM) motor can be controlled to reduce the pedaling torque generated by the human rider. However, the overall cycling torque is affected by external loads, including the cyclist’s weight, wind resistance, rolling resistance, and the road slope. With knowledge of these external loads, the motor torque can be adaptively controlled for these riding conditions. In this paper, key E-bike riding parameters are analyzed to find a suitable assisted motor torque. Four different motor torque control methods are proposed to improve the E-bike’s dynamic response with minimal variation in acceleration. It is concluded that the wheel acceleration is important to determine the E-bike’s synergetic torque performance. A comprehensive E-bike simulation environment is developed with MATLAB/Simulink to evaluate these adaptive torque control methods. In this paper, an integrated E-bike sensor hardware system is built to verify the proposed adaptive torque control.

Permanent magnet motors (PMMs) are widely used in electric vehicles because of their benefits. Based on the permanent magnet topologies on the rotor, PMMs are classified into three types: surface mounted PMM, inset PMM, and interior PMM. This paper discusses a comparison of the characteristics of interior and inset types of PMMs for electric vehicle applications. The study aims to find out the effect of the rotor construction on the magnetic characteristics, torque-speed characteristics, and cogging torque. Simulations were carried out analytically and numerically using the FEMM 4.2 software. The simulation results at the base speed show that the interior PMM generates a higher torque but with a lower rotation, namely 56.47 Nm and 3162 rpm, respectively, while the inset PMM produces higher rotation 4200 rpm but lower output torque of 46.01 Nm. However, with a higher saliency ratio, the interior PMM produces higher maximum torque and speed at both constant torque and field weakening regions than the PMM inset, which is 92.87 Nm and 6310 rpm, consecutively. In terms of cogging torque, the interior PMM raises it slightly higher (2.90 Nm) than the inset PMM (1.93 Nm). The results conclude that, in general, the interior PMM shows better performance in all studied regions and is preferable for electric vehicle applications.

Low‐speed and high‐torque direct‐drive permanent‐magnet motors have found wide applications primarily due to their outstanding performance characteristics. The special applications of these motors demand high reliability against the motor drive system, that is, the power system should have a certain level of fault tolerance. Therefore, the fault‐tolerant motor drive system has been the focus of research all over the world. Many fault‐tolerant motors can only deal with the open‐circuit fault of the winding or drive, and their capability of fault tolerance is substantially limited. When in operation, the short‐circuit fault caused by the ageing of winding insulation may result in more serious hazards than the open circuit in the winding. Such serious faults should be tolerated by the fault‐tolerant system. Moreover, the simpler maintenance or shutdown repair upon completion of fault‐tolerant operation of large‐sized fault‐tolerant motors should also be considered. Therefore, a permanent‐magnet fault‐tolerant motor with module combination stator (MCS‐PMFTSM) and unequal span winding is proposed. By changing the winding structure of the conventional motor the modular operation of the whole motor is achieved, which not only provides the motor with a high fault tolerance capacity but also reduces the downtime during repair and maintenance. In this work, the structure and operating principles of the MCS‐PMFTSM are described followed by the evaluation of the operation performances of the MCS‐PMFTSM under different fault conditions and various control strategies. The fault‐tolerant capacity of this new machine is then analysed, and the prototype is tested with a power of 12 kW and a rated speed of 100 r/min. Both theoretical analysis and test results demonstrate the outstanding operation performance and high fault tolerance of the motor.

This paper investigates the electromagnetic and structural characteristics of a spoke type BLDC motor and provides a comparative study with respect to Interior Permanent Magnet motor (IPM).The electromagnetic analysis aims to determine the average torque and cogging torque of spoke type BLDC motor. The natural and induced vibration characteristics of the motor are evaluated by performing structural finite element analysis. The electromagnetic and vibration characteristics are assessed for different slot/pole combination to provide an insight on their influence on the performance of the motor. In addition, thermal analysis is performed to predict the temperature distribution and a comprehensive analysis of spoke type BLDC motor is presented.

To better address the requirements of integrated equipment, here, a multi‐branch modular permanent magnet motor using a toroidal winding with reverse turn coils is proposed. High‐speed motors have a large winding span, and the use of a toroidal winding with reverse turn coils in place of lap windings can effectively shorten the length of the motor end. Motor modularisation can improve production, assembly efficiency, and the maintenance economy. To innovate the windings from a basic toroidal winding, a modularised toroidal winding with reverse turn coil is proposed which enables the motor to be decoupled in electrical and mechanical structures. The inductance parameter calculation and finite element simulation verification are carried out on the new winding structure and the lap windings. The feasibility of the 60‐degree phase toroidal winding with a reverse turn coil structure with reverse turns is also assessed. The no‐load back electromotive force of the new winding structure is a square wave, which will bring certain torque fluctuations. To improve the performance of the motor, the method of radial magnetic pole segmentation is used, and the new magnetic pole is analysed and verified by the segmented magnetic circuit. Finally, the combination of magnetic pole segmentation is explored, and the effect of different segmentation methods on the performance of the motor is compared.

This paper develops an adaptive type-2 fuzzy logic controller for direct torque control of a permanent magnet synchronous motor. The type-2 fuzzy logic systems are used for modeling the unknown functions. The adaptive law proposed takes in consideration the compensation of reconstruction errors by adding a sliding mode term. This term ensures the stability and the robustness of the control system regardless the internal and external disturbances. The stability of closed-loop system was verified using Lyapunov’s stability theorem. Moreover, the proposed control scheme guarantees that all involved signals are bounded. The effectiveness and the feasibility of the proposed control method are demonstrated by extensive presentation and discussion of simulation results.

In order to optimize and analyze the cogging torque of hybrid stator motor, a hybrid stator motor is taken as the research project. The axial distribution of air gap magnetic flux density was analyzed, and the analytical formula of the cogging torque of the hybrid stator motor was derived. Combined with the cogging torque analytical formula, the superposition calculation method of cogging torque of hybrid stator motor was proposed, and the correctness of the superposition calculation method was verified by simulation analysis. The silicon steel segment and the amorphous alloy segment of hybrid stator core were optimized by using the uneven air gap structure, and the optimized results of the silicon steel segment and the amorphous alloy segment were obtained by two-dimensional simulation. Based on the results of two-dimensional simulation analysis, a three-dimensional model was built for simulation analysis. After optimization, the cogging torque of the motor was weakened by 48.1% and the torque ripple was reduced by 1.32%, while the loss and output torque remained basically unchanged.

The paper analyzes the main techniques and technologies of oil fluid recovery in the context of energy consumption, significantly rising over the latest decade. It is recognized that the number of publications in the area of energy efficiency is growing steadily. Currently Russian oil and gas industry are facing the task of accelerating reduction of energy consumption while preserving, or even increasing, production rates. The task is complicated by the fact that the majority of deposits in Russia either have already entered (primarily, Volga-Ural region) or are now entering (West Siberia) their last stage of exploration, whereas new deposits in East Siberia are only being brought into production. Furthermore, a lot of new deposits, which provide for high recovery rates, are profitable a priori as at the first stage of exploration they do not need any artificial lift due to their free flow production without any oil well pumps. However, there is a significant share of new deposits with low-permeability reservoirs, which require either a system of reservoir pressure maintenance or periodic hydraulic fracturing. At the same time deposits at the late stages of exploration, apart from the use of pump units, systems of reservoir pressure maintenance and hydraulic fracturing, require regular repair and restoration, measures against salt and heavy oil sediments, mechanical impurities, flooding, etc., which all has a negative effect on well profitability. In order to solve these problems, the authors review existing methods and calculate specific energy consumption using various pump systems for hypothetical wells, varying in yield. According to the research results, it has been revealed that from the point of view of energy efficiency, it is desirable to equip low- and low-yield wells with sucker rod progressive cavity pump units, medium-yield ones – with electric progressive cavity pumps driven by permanent magnet motor, medium- and high-yield wells – with electric progressive cavity pumps or electric submersible pumps driven by permanent magnet motor, depending on the characteristics of the pumpedout oil fluid.

The large current ripple caused by the limited switching frequency significantly degrades the control performance of the high-speed permanent magnet motor drive system. To mitigate the current ripple, the switching frequency of the inverter should be high enough. The purpose of this article is to reduce the current ripple of the HSPMSM drive system. First, a Silicon-Carbide/Silicon(SiC/Si) hybrid inverter is designed. The designed hybrid inverter consists of two SiC-MOSFETs and six Si-IGBTs, and the circuit modals of the SiC/Si hybrid inverter are analyzed. Second, based on the SiC/Si hybrid inverter, three improved space-vector-modulation (SVM) strategies are proposed. The core principle of the proposed SVM strategies is that most of the switching actions are transferred from the Si-IGBTs to the SiC-MOSFETs. The benefit from the low switching loss of the SiC device is that the total power loss can be significantly reduced. Besides, the SiC-MOSFETs can create the zero-voltage-switch condition for the Si-IGBTs, and then the switching loss of the Si-IGBTs can be almost eliminated. Finally, to verify the effectiveness of the proposed methods, sufficient simulations and experiments are implemented. The stator current ripple, total-harmonic-distortion, and the conversion efficiency of the inverter in the full power range are compared under the same condition based on the full-Si-IGBT inverter, the full-SiC-MOSFET inverter, and the SiC/Si hybrid inverter. The evaluated results sufficiently verify the superiority of the proposed SiC/Si hybrid inverter and the improved SVM strategies.

Due to the need for developing technology and comfort today, the use of electric motors increases in different fields such as pumps, household appliances, fans, aerospace and mixers. This affects energy consumption and production costs, and ultimately triggered the development of higher performance motors. Because of the multi-parameter designs and nonlinear structure of electric motor, it has become very important the use of multi-objective optimization algorithms in design studies on electric motors. At the same time, real-time simulations are provided by using finite element analysis programs to reduce test costs. This study purposes analysis and multi-objective design optimization of a direct drive permanent magnet synchronous motor with external rotor for low speed and high torque mixer applications. So, the third-generation algorithm NSGAIII was used and compared with the second-generation algorithm NSGAII. To examine both initial design result and optimization results Ansys/Maxwell program was used. According to the initial result, optimized motor geometries provided an efficiency increase of about 3.54% and a cost reduction of about 17%. In addition, the search strategies of both algorithms were compared on motor design parameters.

The rotor eddy current loss of high‐speed permanent magnet motor has an important influence on the temperature distribution of permanent magnet. In traditional method, the unbalanced distribution of eddy current in permanent magnet is ignored, and the eddy current loss is applied to the calculation of temperature field in the form of average heat density, which makes a certain error in the calculation of the temperature field in permanent magnet motors. This study proposes the 50 kW and 30,000 rpm high‐speed permanent magnet prototype and an eddy current loss segmentation model of permanent magnet. The unbalanced distribution of eddy current in permanent magnet is considered in this model, and the permanent magnet is divided into different regions. According to the eddy current loss segmentation model, the eddy current losses in different regions are obtained, then the heat density in different regions of permanent magnet is applied to the calculation of temperature field in the motor. The application of the proposed model is simple and convenient, and makes temperature simulation results closer to the actual situation. At the same time, in order to verify the accuracy of the model, the temperature calculation results using the proposed model are compared with the traditional method, and both the results are verified by relevant experiments.

This article aims to implement a fan motor design with an airfoil-shaped rotor via the newly developed 3-D printing method. This integrated design is originated from a flux-switching permanent magnet motor, in which the motor rotor can directly produce airflow without any external impellers. Such a design and manufacturing process can effectively enhance the robustness of the fan motor structure and increase its power density. This article adopts 3-D finite element analysis for electromagnetic and fluid field simulation. Moreover, a new metal 3-D printing method with a low core loss feature during high frequency operation is applied. Finally, the experimental results with a prototype are presented to verify the designed performance.

Many-objective problems, characterized by a high-dimensional objective space, are a source of challenge for standard methods of multi-objective optimization. An evolutionary algorithm based on the concept of least-conflict solutions is here presented; the shape design of a IPM motor is considered as the case study. In particular, optimization problems dealing with 3 and 4 objective functions have been solved, respectively.

Double-layer winding halbach fault-tolerant motor (DLW-HFTM) combines the advantages of the permanent magnet motor and the fault-tolerant motor, which are beneficial to improve the characteristics of the joint robot. First, the structure of DLW-HFTM is proposed in view of the requirement of the fault tolerance of drive motor on the joint robot without degrading the other performances, such as the torque and the efficiency. Then, the working principle and initial design dimensions are depicted, and a finite element parameter model is established by Maxwell software. Furthermore, the design parameters are optimized by multi-objective sensitivity analysis. Finally, the electromagnetic performances before and after optimization are analyzed, including no-load back EMF, torque, loss, efficiency, etc. Meanwhile, the fault-tolerant performance of the motor is analyzed. The research results show that the DLW-HFTM can improve the fault-tolerance on the condition of meeting the design requirements.

This paper proposes a resolver offset calibration algorithm that can detect offset with high precision just by configuring a very simple experimental environment. This use of a simple experimental environment holds a great advantage for large-capacity permanent magnet synchronous motors (PMSMs) that require substantial resources to configure an experimental environment, such as EV traction motors. The proposed algorithm is designed based on the PMSM voltage equation. The algorithm is first verified for its validity through simulation with Simulink. Subsequently, it is implemented based on the C-language and installed on an inverter for verification experiments. The implemented algorithm is very simple and requires little execution time and memory. The error in the calibrated offset is experimentally found to converge within 3-bits based on 12-bits (the resolution of the commonly used RDC), and the results have very little deviation.

Tubular permanent magnet motor (TPMM) can offer great thrust force density and high efficiency. To enhance its robustness against disturbances and solve the contradiction between response time and overshoot, a novel sliding mode control strategy based on disturbance observer (DOB-SMC) was proposed for a TPMM velocity drive system. The novelty of the proposed velocity control strategy lies in the incorporation of the mismatch disturbance observer in the sliding surface and the sliding mode control (SMC) law, and the introduction of internal model control (IMC) into the SMC law. The velocity control system is transformed to a first-order inertia model by IMC, thus the dynamic response performance is improved. The mismatched disturbances are estimated and the equivalent control voltage is employed, and then the effect of mismatched and matched disturbances can be restrained with little chattering. The simulated and experimental results are presented as validation for the proposed strategy.

The search for more competitive equipment in the global market has led to the implementation of new materials and technologies in the search for greater energy efficiency. This is certainly a guideline followed by the electric motor industry that has introduced new technologies in rotating machines, such as the permanent magnet motor, evolving into increasingly efficient motor classes. However, subjecting these efficient motors under nonideal electric grid power conditions, such as voltage unbalance, can cause these efficient machines to generate additional distortions in the voltage and current waveforms, which in turn not only affect the performance of electric motors themselves but also that of the electrical system in general. This work presents a comparison between energy efficiency gain and the corresponding power quality degradation through a detailed harmonic analysis of the effects of voltage harmonics and voltage unbalance in three 0.75-kW electric motors classes: IE2, IE3, and IE4, The results show that for increasing percentages of a specific harmonic distortion, other harmonics are also increased in the higher efficiency electric motors sample analyzed, and similar responses were also observed for large percentages of voltage unbalance, mainly in the line-start permanent magnet motor class IE4. The results achieved are interesting but rigorously reflect only the tested motor sample and cannot be generalized to all motors, in other power ranges, of the respective motor classes tested. For generalization, exhaustive tests must be accomplished to formulate general conclusions according to the electric motors’ classes commercially available.

This paper presents the 3-leg linear permanent magnet motor (TLPMM), which has a novel structure. It has an advantage of reducing the entire volume due to the attraction force cancellation. The TLPMM consists of stator and mover modules, simplifying the manufacturing process and maintenance. The TLPMM has a permanent magnet skew and overhang structure to improve motor performance. Therefore, the consideration of three dimension (3D) effects is required in the characteristic analysis. The proposed method is based on a field reconstruction method that provides a reduction in computational burden with high accuracy in analyzing 3D characteristics. For the evaluation of magnetic fields in non-uniform and complex air-gap in the TLPMM, the virtual air-gap section method is introduced. Using these proposed methods, the TLPMM with the magnet skew and overhang structure are effectively analyzed. This approach was verified by comparison with finite element analysis and experimental results.

This paper proposes an optimal design for a surface-mounted permanent magnet motor (SPMM) to reduce torque pulsations, including cogging torque and torque ripple, by using multi-grade ferrite magnets. Based on a conventional SPMM with single-grade ferrite magnets, the proposed SPMM is designed with four-grade ferrite magnets and then optimized to minimize torque pulsations by maintaining the required torque, utilizing the Kriging method and a genetic algorithm. The results obtained by the finite element analysis show that the optimized SPMM with multi-grade ferrite magnets exhibits improved airgap flux density distribution with highly reduced cogging torque and torque ripple by maintaining the same average torque, as compared to the conventional SPMM. Furthermore, the analysis of the working points for the multi-grade ferrite magnets reveals that the optimized SPMM has good durability against the irreversible demagnetization.

The audible harsh switching noise from permanent magnet synchronous motors (PMSMs) is generated by pulse width modulation (PWM) technique applied in voltage source inverters(VSIs). This paper proposes a method based on a known modified PWM strategy for two-level VSIs. The proposed method alters the zero vector in one of the two carrier period at the cost of increasing switching frequency of one phase and changes the carrier period randomly. It not only completely eliminates the PWM noise nearby odd-order carrier frequency but also reduces even-order carrier frequency noise. The elimination principle as well as the simulation have been demonstrated. Finally, the effectiveness of the proposed method has been confirmed by detailed experimental results. The dynamic performance are also investigated.

The multi-phase permanent-magnet motors are suitable choices for certain purposes like aircrafts, marine, and electric vehicles due to the fault tolerance and high-power density capabilities. The paper aims to design and prototype an optimized five-phase fractional slot concentrated windings surface mounted permanent magnet motor. To optimize the designed multi-phase motor, a multi-objective optimization technique based on the genetic algorithm method has been applied. The machine design objectives are to minimize mass and loss, subsequently, to determine the best choice of the designed machine parameters. Afterwards, 2-Dimensional Finite Element Method (2D-FEM) has been used to verify the performance of the optimized machine. Finally, the optimized machine has been prototyped. The results of the prototyped machine have validated the results of the theatrical analyses of the machine, and accurate consideration of the parameters improved the performance of the machine.

To enhance the steady-state performance of the virtual-vector-based model predictive current control (VV-MPCC) for a five-phase flux-switching permanent magnet motor, an improved multi-vector-based MPCC (MV-MPCC) method with geometric solution is proposed and investigated in this article. The desired voltage is employed to preselect voltage vector candidates and provide a guidance for the geometric division of a sector. According to the link between the reference voltage and the division, the optimal voltage vectors are determined and their duty ratios are obtained by projection method. Compared to the conventional MV-MPCC method using derivative method, the proposed geometric MV-MPCC method employs the desired voltage to quickly determine the voltage vectors and the corresponding duty ratio, which not only alleviates computational burden but also favors for more intuitive implementation. Finally, the effectiveness of the proposed method is verified by experiments.

One of the key challenges for the electric vehicle industry is to develop high-power-density electric motors. Achieving higher power density requires efficient heat removal from inside the motor. In order to improve thermal management, a multiphysics modeling framework that is able to accurately predict the behavior of the motor, while being computationally efficient, is essential. This paper first presents a detailed validation of a lumped parameter thermal network (LPTN) model of an Internal Permanent Magnet synchronous motor within the commercially available motor-cad modeling environment. The validation is based on temperature comparison with experimental data and with more detailed finite element analysis (FEA). All critical input parameters of the LPTN are considered in detail for each layer of the stator, especially the contact resistances between the impregnation, liner, laminations, and housing. Finally, a sensitivity analysis for each of the critical input parameters is provided. A maximum difference of 4%—for the highest temperature in the slot-winding and the end-winding—was found between the LPTN and the experimental data. Comparing the results from the LPTN and the FEA model, the maximum difference was 2% for the highest temperature in the slot-winding and end-winding. As for the LPTN sensitivity analysis, the thermal parameter with the highest sensitivity was found to be the liner-to-lamination contact resistance.

In the proposed work, a modified look-up table-based direct torque control (DTC) scheme is reported for a neutral point-clamped three-level inverter-fed interior permanent magnet synchronous motor ...