Reluctance Motor Research Articles

Evaluation of a Recycling Strategy for Polymer-Bonded Magnets Based on Thermosets

Polymer-bonded magnets are increasingly being used in terms of applications in drive technology and, more specifically, in new concepts based on reluctance motors. The increasing demand for polymer-bonded magnets, especially in the context of electromobility, is leading to a shortage of materials, mainly in terms of the finite resource neodymium–iron–boron (NdFeB). So far, the recycling strategy for polymer-bonded magnets based on thermosets is pyrolysis, which leads to either a massive reduction of the magnetic properties or a high energy requirement. Therefore, the paper investigates an alternative recycling strategy for polymer-bonded magnets based on thermosets based on the reusage of shreds. Several influencing factors such as the form of the carrier material and the temperature level were varied in order to find a suitable recycling method. It was found that the magnetic properties were reduced by at least 15% compared to the pure material. The required energy and the CO2 emission were reduced by 90% compared to the pyrolysis. Thus, the strategy of recycling polymer-bonded magnets based on thermosets by the reusage of shreds leads to improved conditions compared to pyrolysis and is, therefore, a suitable alternative.

Fuzzy adaptive terminal sliding mode control based on recurrent neural network compensation for a maglev system

Reluctance motor has high force density while strong uncertainties. This paper concentrates on the research of the intelligent control method for a reluctance-motor maglev system (RMMS) with limited system information. To this end, we propose a new fuzzy adaptive terminal sliding mode control (FATSMC) method based on a novel full-regulated recurrent neural network (RNN) compensator. The RNN approximates the lumped uncertainty of the RMMS, and the controller handles the residual error and external disturbances. The presented increasing–decreasing fuzzy adaptive law, without the prior knowledge of uncertain upper bound, adjusts the switching gain by the dynamic information of the system. And the overestimation of the switching gain can be reduced. Moreover, the proposed method only uses the nominal parameters and model of the RMMS, thus avoiding complex modeling. This study provides strong support for the application of RMMS in high-precision situations. By constructing a Lyapunov function, the stability of the proposed method is analyzed, which is uniformly and ultimately bounded (UUB). In the experiment, the proposed method is compared with three existing methods in four cases. The results demonstrate that the presented method achieves nanoscale suspension accuracy, suppresses chattering significantly, and has strong robustness.

A 2D and 3D Analysis on Electromagnetic Parameters of Spoke-shape Interior Permanent Magnet Synchronous Motor Using FEM

In industry, the most frequently used motors are induction motors (IMs), reluctance motors, and permanent magnet synchronous machines (PMSMs). Nowadays because of higher efficiency with higher power density, PMSM attracts its uses in every field of application. Hence, a spoke shape interior PM-based synchronous motor (IPMSM) with distributed winding is considered to discuss in this paper. Also, there has always been a dispute between 2D and 3D analysis of electromagnetic parameters of machines. Therefore, this paper discusses the accuracy, advantages, and difficulty level of 2D and 3D FEM analysis of the IPM motor model by considering several electromagnetic with electromechanical parameters such as torque, flux linkage, eddy current loss, etc. The performance of five different core materials is also considered for comparison. These analyses are carried out by using ANSYS Maxwell software. Spoke shape IPMSM of 0.55 kW with 220 V, 50 Hz is considered for analysis. The 2D and 3D comparison results of parameters under magnetostatic and transient conditions are presented and verified with the results reported in the literature. 2D FEM analysis has given more value in case of torque, stator current, and magnetic flux density than 3D analysis where as 3D analysis is give good performance for flux linkage, back EMF, and eddy current losses. Significant percentage changes with respect to observed materials in the results of 2D and 3D cases are reported. Silicon Steel M36 suitability for stator and rotor core is also observed. This 2D and 3D FEM analysis clarifies accuracy prior to design motor.

A review of motor neural system robotic modeling approaches and instruments

In this review, we are considering an actively developing tool in neuroscience-robotic modeling. The new perspective and existing application fields, tools, and methods are discussed. We try to determine starting positions and approaches that are useful at the beginning of new research in this field. Among multiple directions of the research is robotic modeling on the level of muscles fibers and their afferents, skin surface sensors, muscles, and joints proprioceptors. Some examples of technical implementation for physical modeling are reviewed. They are software and hardware tools like event-related modeling algorithms, reduced neuron models, robotic drives constructions. We observe existing drives technologies and prospective electric motor types: switched reluctance and transverse flux motors. Next, we look at the existing examples and approaches for robotic modeling of the cerebellum and spinal cord neural networks. These examples show practical methods for the model neural network architecture and adaptation. Those methods allow the use of cortical and spinal cord reflexes for the network training and apply additional artificial blocks for data processing in other brain structures that transmit and receive data from biologically realistic models.

Injection Moulding of Multipolar Polymer-Bonded Magnets into Soft Magnetic Inserts for Rotors in Reluctance Motors

Due to lower magnetic properties of polymer-bonded magnets compared to sintered magnets, a complete redesign of the multipolar soft magnetic flux barriers in rotors with alignment guidelines was carried out to eliminate the frequently used rare-earth magnets, causing a new influence of the outer magnetic field on the cavity by using soft magnetic inserts. Within this new process, the main influencing factors on the magnetic flux density such as filler content, tool temperature, holding pressure and injection velocity were analysed and correlated. The studies were based on the compound of Polyamide 12 and up to a 60 vol.-% of the hard magnetic filler, strontium ferrite. Based on the study, the injection moulding of multipolar-bonded magnets into soft magnetic inserts for rotors and, in turn, into complex geometries can be optimized in terms of the orientation of the filler, the microstructure and the magnetic flux density. The investigations show no significant influence of the process parameters known from the literature such as the mass temperature Tm, which affects the magnetic flux density, as well as the orientation and the microstructure similar to tool temperature Tt, but is less efficient. The main influencing factors identified during the investigations are the tool temperature Tt, the injection velocity vin and the holding pressure ph. As known influencing factors are only based on simple geometries such as ring structures or plates, new factors were determined for complex rotor geometries.

Efficiency Analysis of Fractional KiloWatt Reluctance Motors with Various Frame Sizes, Taking into Account the Impact of the Punching Process

The need to reduce electricity consumption by electrical devices, including electric motors, is the reason for the development of new designs. Designers strive to improve operational parameters, including efficiency, using, for example, new types of magnetic materials, new types of stator windings, etc. Currently, in mass production, motor cores are made of punched laminations—punching causes damage of core parts. For motors of relatively large geometrical sizes, this effect is ignored during design. For motors having small dimensions, this negative effect results in a reduction in efficiency, which is mostly small for this type of motor. In this paper, the authors propose a new rapid algorithm based on simple measurements to determine the material characteristics of the damaged material part. Then, using them in the FEM models, they determine the efficiency of motors with various powers and frame sizes. On this basis, the conclusions are formulated, they may be helpful for motor designers.

Review of Electrical Motor Drives for Electric Vehicle Applications

EVs (Electric Vehicles) have been rejuvenated over the last decades while the motor drive technologies are still evolving. This paper provides a review of electrical motor drive technologies used in EV applications, with a performance comparison of candidate machines and their drive topologies. EV applications demand high efficiency, high torque density, high reliability, and wide speed range while reducing weight, complexity, total costs and environmental impact. In the literature, DC (Direct Current) motors, IMs (Induction Motors) and PM (Permanent Magnet) motors can be generally found in marketplace whilst RMs (Reluctance Motors) have been researched for some time and are nearing commercial availability. This paper evaluates the performance of these four main types of electrical motor drives for EV propulsion applications using analytical methods. PM motors may offer the best performance in terms of torque density and compactness but the cost is the highest (primarily dominated by rare-earth permanent magnets), limiting their widespread application in mass production EVs. DC motors have their own merits but suffer from limited power density and necessity for maintenance. Induction motor drives are a mature and proven technology. In particular, squirrel-cage IMs are robust, reliable and inexpensive, striking a balance between system cost and complexity, power density and extended speed range. Reluctance motors can provide a good torque density and cost effective EV drive solutions. Their drawbacks can also be overcome by the use of power electronic converters and advanced control strategies. Induction and reluctance motor drives are well suited for cost sensitive mass production EV applications. Looking to the future, increased hybridization may be a way forward in industry which combines attractive features of different electrical machines and control algorithms and still offer much promise in performance and total cost. At last, reliability study on EVs requires historical information and driving patterns, demanding research expertise in eco-sociology, human behaviors as well as human-machine interface.

Ultra-High Speed Switched Reluctance Motor-Generator for Turbocharger Applications

This paper proposes technical guidelines, modelling, and control of an ultra-high-speed-switched reluctance motor- generator for automotive turbo-charged assistance and energy recovery. Creation of an ideal model using electromagnetic finite element analysis and conducting a low cost/ low scale experiment is proposed. The first objective focuses on the transient simulation process. The second objective focuses on an investigation of the proposed control criteria. The modelling and analysis of a “Switched Reluctance Motor” (SRM) is an initial task for the selection of the coupled mover. Two controllers are selected for the experiment which consists of a generally low-cost solution and an optimized development board for prototyping optimization. The low-cost control solution is implemented with an Arduino Uno and an assortment of relays configured into an asymmetrical half bridge. The second controller is the “Digilent Zed Board Zynq-7000 ARM/FPGA SoC Development Board” (Zed board). ANSYS 2D, 3D modelling, data simulation for the stator and rotor are implemented. Current, voltage, and flux for all phases waveforms are included. Rotor dynamic simulation, machine transient simulations, and some other characteristics are depicted through 3D figures.

Design methodology for high‐speed synchronous reluctance machines

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.

Motion Sensorless IPMSM Control Using Linear Moving Horizon Estimation With Luenberger Observer State Feedback

This paper presents an investigation of motion sensorless control based on the frame work of moving horizon estimation (MHE), validated experimentally with a rear axle electrical drive unit used in automotive applications. Both steady-state performance and dynamic performance, including speed reversal, are investigated. In addition, a well-established active flux-based observer is implemented and referenced to objectively evaluate the proposed MHE. It is shown that the proposed solution is feasible, that the associated dynamic optimization problem can be solved in real time, while exploiting the attractiveness of the approach to obtain highly accurate estimates. Moreover, the absence of ${d}$ -axis flux in the proposed solution is considered a significant strength. Conclusively, it turns the proposed solution into a universal solution for any synchronous motor, regardless of whether a PM, PM-assisted, or reluctance motor is used, nondependent on the presence of magnetic saliency.

Field Weakening Characteristics Computed with FEM-Coupled Algorithms for Brushless AC Motors

Finite Element Method (FEM) analysis tools are the most adopted in the design of brushless alternating current motors due to the advantage of considering multi-physics effects with dependencies of variables such as cross-coupling, saturation and others that are not possible to be modeled analytically with high precision. During the design process designers compute operation points such as maximum torque per ampere or flux weakening characteristics that cannot be targeted directly on the FEM tool. Therefore, designers make a sweep of simulations and post-processed the data in order to obtain the results, this is repetitive particularly in the conceptual phase of the design where features of the motor are still not defined. This paper presents nine algorithms as an alternative to compute with iterative methods operation points that cannot be targeted directly on a FEM tool. The algorithms must be coupled to the FEM tool and can compute complex points such as the characteristic current and modes of operations limits within acceptable range of error and times of execution for practical purposes. Validation of the algorithms using Jython is presented with results for the three types of brushless motors (non-salient, interior permanent magnet and reluctance motor).

Nonlinear Analytical Model of Eccentric Synchronous Reluctance Machines Considering the Iron Saturation and Slotting Effect

This paper deals with an improved analytical model of synchronous reluctance (REL) machine considering rotor eccentricity. This model considers the magnetic saturation in the iron parts of both the stator and the rotor. This saturation results from the actual B–H characteristic of the iron. In addition, the slotting effect is considered in the analytical model. The unbalanced magnetic force (UMF) on the rotor is accurately estimated. Furthermore, the impact on the estimated UMF due to the slotting effect and the magnetic saturation is studied. Both static and dynamic eccentricity cases are considered. As an example, a four-pole 36-slot REL motor with three flux-barriers per rotor pole is considered. Experimental measurements confirm the results achieved by means of both finite-element analysis and the improved analytical model.

Experimental Comparison of PM-Assisted Synchronous Reluctance Motors

The aim of this paper is to show the results of various experimental tests carried out on synchronous reluctance (REL) motors with different rotor geometries, as proposed in technical literature. The impact of the assistance of ferrite permanent-magnet (PM) inset in the flux barriers is considered: PM-assisted REL motors are compared with synchronous REL motors, highlighting the main benefits of the former solution. The effect of the rotor skewing and of adopting asymmetric geometries of the flux barriers to reduce the torque ripple is investigated by means of several tests. The impact of the lamination is also considered, as far as the overload capability is concerned. In addition to the experimental tests, a finite-element model is adopted to predict the performance of the motors. The predicted results are compared with the experimental ones in a wide operating range, showing a good agreement.

軸方向電磁力リプル低減によるアキシャルギャップ型SRモータの振動・騒音低減に関する検討

SUMMARY Switched reluctance (SR) motors are motors that utilize the reluctance torque originating in the magnetic saliency between the stator and the rotor, which are made up of an electromagnetic steel sheet and windings without a permanent magnet. Because of their robustness and simple structure, SR motors are suited for use as the in-wheel motor for traction motors of vehicles. In a flat space such as is present in in-wheel motors, the axial-gap structure has an advantage compared with the conventional radial-gap structure for the space factor of a motor. An axial-gap in-wheel SR motor was tested in a microbus, and the bus could be successfully driven. The test results regarding the motor performance were satisfactory. However, the motor emits a loud sound. The acoustic noise of the axial-gap SR motor is mainly caused by the axial electromagnetic force. This paper presents a method of reducing acoustic noise that is based on a model of the electromagnetic force on the axial-gap SR motor.

Formation of failure matrix and failure–free control algorithm for multi–sectioned Switched–reluctance drive

We review fault-tolerant switched reluctance drive with sectioning of the three–phase stator winding. In the operating process of an electric drive, there will be continuous monitoring of the operating state on the basis of a developed algorithm to analyse drive operability and formation tabulate a failure matrix. The paper introduces a failure–free control algorithm for multi–section switch – reluctance motor with formation the assignment values of amplitude phase currents taking into account the failure matrix. We show that in an emergency such single failure or multiple failure in switched–reluctance drive it is possible to provide reduction of torque fall and pro–gressively stock depletion with providing fault–tolerance of drive system. A method of residual life evaluation is proposed on the basis of calculating the coefficient of operability of the electric drive system that gives possibility to control the endurance of electric drive in real time from operational to completely unusable.

Evaluation of Space Vector Switching Patterns Based on Reference Functions and Switching Loss Factor in VSI Fed Induction Motor Drive

Space vector pulse width modulation (SVPWM) technique has become the most popular and important PWM techniques for three-phase voltage source inverters (VSI) fed control of induction, brushless dc, switched reluctance (SR) and permanent magnet synchronous motors. SVPWM is a method of pre-calculation of switching timing instants for various sections of target output which has options in terms of positioning vectors inside every sampling interval. Even though the basic structure for all SVPWM variants is same, there are more options in the arrangement of the voltage vectors in each sector. Competency of difference SVPWM variants can be understood through their analog equivalencies (reference). This paper presents eight different variations of SVPWM. A comparative evaluation of all these variants in terms of attributes such as switching loss factor (SLF), distortion factor (DF) and total harmonic distortion (THD) in output line voltage is reported. Simulation results are provided to illustrate the analysis.

Experimental Evaluation of Characteristics of SR Motor Made of Permendur

A switched reluctance (SR) motor has a doubly salient pole structure. The performance of the SR motor strongly depends on the magnetic properties of the core material since it consists only of an iron core and copper windings. This study experimentally evaluates the performance of an SR motor made of permendur (Fe-49%Co alloy), which has very high saturation flux density and low core loss. Two types of SR motors that have the same dimensions but different core materials are used: one motor is made of the conventional non-oriented Si steel, and the other is made of permendur. Comparison of the characteristics of the two motors shows that the performance of the permendur SR motor surpasses that of the conventional one in terms of output power and efficiency.

New fault-tolerant flux-mnemonic doubly-salient permanent-magnet motor drive

By incorporating the flux-mnemonic concept into the hybrid-field doubly-salient permanent-magnet (DSPM) motor structure, the resulting flux-mnemonic DSPM motor not only offers efficient online air-gap flux control, but can also flexibly operate as a DSPM motor when the PMs are magnetised or a switched reluctance (SR) motor when the PMs are demagnetised. The key of this study is to artfully utilise these modes of operation for the proposed flux-mnemonic DSPM motor drive. Namely, the motor drive works in the DSPM mode during open-circuit fault, and changes to the SR mode during short-circuit fault. Both computer simulation and experimental results are given to verify the validity of the proposed fault-tolerant flux-mnemonic DSPM motor drive.

Reluctance machines incorporating high temperature superconducting materials on the rotor

The computer modelling of reluctance machines with rotors containing both iron and high temperature superconducting (HTS) materials, using the finite element method (FEM), is presented in this paper. The modelling permits to obtain the field and stator current distribution from where reluctance torque is evaluated. Different solutions are analyzed and experimental results on a 2 kW reluctance motor using HTS materials on the rotor and cooled by liquid nitrogen, show a significant increase in the torque values, when compared with that of a correspondent conventional machine. Pre-magnetization of these rotors by field cooling is explained and this process gives a mechanical output power undoubtedly better than that of a conventional reluctance machine.

Switched reluctance and permanent magnet brushless motors in highly dynamic situations: a comparison in the context of electric brakes

Electromechanical brake (EMB) systems offer the potential for enhanced vehicle control while simplifying the car assembly as well as recycling process. This article offers a comparison of two motor technologies, switched reluctance (SR) and permanent magnet (PM) brushless, motor in highly dynamic situations, in all four quadrants of their torque-speed operating regions, for an EMB application and also describes the motor designs and their static characteristics, before examining in depth their dynamic behavior, in particular special control adaptations to enable the SR motor to reverse rapidly when needed. A 20% longer SR motor provided overall similar dynamic performance, but only if the SR motor is fitted with a speed limit. A method to choose such a speed limit was developed, and the software algorithm implementation was found to be simple and successful.