Spoke Type Research Articles

On the relation between performance and permanent demagnetisation in spoke type machines with ferrite magnets

On the relation between performance and permanent demagnetisation in spoke type machines with ferrite magnets

Maintaining Average Torque and Suppressing Torque Ripple with T-shaped Auxiliary Pole for Spoke Type Multi-consequent-Pole Motor

Maintaining Average Torque and Suppressing Torque Ripple with T-shaped Auxiliary Pole for Spoke Type Multi-consequent-Pole Motor

Using Reluctance Torque Theory in Spoke Type Permanent Magnet Vernier Motors to Increase Average Torque

Using Reluctance Torque Theory in Spoke Type Permanent Magnet Vernier Motors to Increase Average Torque

Analysis of isolated phase windings and permanent magnet assists high energy efficient hybrid‐reluctance motor for electric vehicle

AbstractThis article describes the electromagnetic analysis of high efficient hybrid motor, which comprises the salient features of switched reluctance motor (SRM) and spoke‐type brushless DC motor. The main objective is to develop a motor with a high‐power density and winding faulty capability. Furthermore, this research article extends in the manner to increase the power density of the motor through the sensitivity analysis on rotor geometry by replacing the rotating part of SRM and adopting the rotor of spoke type brushless DC motor, originating the hybrid motor with the high‐power density and enhanced efficiency. To ensure the winding fault capability, a SRM‐based stator winding is adopted. Then, the modelling process for hybrid motor 48 V, 1500 RPM, 2 kW, and 12.7 Nm are detail in both analytical and finite element methods. The electromagnetic analysis is carried out to estimate the torque characteristics and flux pattern of the proposed motor. Furthermore, the proposed motor is analysed with the selection of laminating core material among M 27 24 Ga, 36F155, 46F165, 47F165, M 420 50D, and arnon 7. This infers 36F155 material assists proposed motor has high‐performance characteristics. The vibration frequencies are investigated in modal aspects to estimate the natural frequencies of vibrations. These analyses are validated among analytical and finite element results under no‐load conditions.

Comparative evaluation of different permanent magnet materials for spoke interior permanent magnet motor suitable for automotive application

Spoke Interior Permanent Magnet Synchronous Motors (IPMSM) are regarded as a potential substitute to conventional IPMSM in electric four wheeler application due to its simple construction, wide speed torque characteristics, improved power factor, efficiency and high torque density. The traditional IPMSM employs Neodymium Ferrite Boron (NdFeB) magnets, which have high torque density. But, the problems associated with NdFeB magnets include demagnetization owing to high operating temperature, high investment cost, brittleness which leads to high stress distribution in the rotor with torque ripple, high cost of maintenance and existence of cogging torque. Therefore, this work attempts to design and analyze Spoke type IPMSM different permanent magnet materials such as Samarium Cobalt (SmCo) and Y30 type Ferrite Magnets (rare earth free magnet), to evaluate the torque density, efficiency, requirement of cooling in order to reduce thermal demagnetization, Von-Mises stress and cogging torque. The volume of the motor is varied for various permanent magnet materials. The results of this work provides insight into the various performance measures with respect to choice of different magnetic materials suited to electric four wheeler (automotive) application.

The Implementation of the Proposed Teaching Methods in the Curricula of Language Courses during the Use of Online Teaching in the Period of Covid-19: Opinions and Attitudes of Greek Teachers

Because of the coronavirus pandemic and its consequences, distance education and, in particular, "Online Education" (OE) was used in the educational systems of many countries, as in Greece. The main objective of this application was to keep students in touch with the educational reality, but also with the teaching and learning process. On this basis, the purpose of this study is to investigate the attitudes and opinions of Greek Primary Education teachers and Secondary Education teachers' philologists regarding the implementation of the proposed methods of teaching language courses in the use of OE. Seven hundred and thirty-four teachers constituted the sample of the study. A structured questionnaire was used to carry out the research and collect the data and the main findings of the research can be summarized as follows: the teachers' attitudes and opinions regarding the correlation of the proposed teaching methods in the Curriculum - such as the possibility for all students to produce various types of spoken and written language and the units designed for the cultivation of literacy to have the form of an action plan (project), etc. - with the use of OE are approximately neutral, namely neither positive nor negative.

Design of a Spoke Type PMSM With SMC Stator Core for Traction Applications

This article presents four different slot/pole configurations to select the best slot/pole for a traction application with a wide speed range. The electromagnetic performances are improved for the selected slot/pole configuration. This paper presents a modified spoke type rotor that significantly reduces the torque ripple, back electromagnetic force (EMF) harmonics, and cogging torque from conventional spoke type designs. The effectiveness of the modified spoke type rotor is proved with state-of-the-art designs such as Toyota Prius and Honda Accord motors. Along with the modified spoke type rotor it focuses on a segmented soft magnetic composite (SMC) stator core to improve the copper fill factor and improve torque density by reducing the tooth length to allow additional space for the end windings within the stack length of the motor. A comparison between the laminated steel stator and SMC stator is presented. The laminated motor is capable of producing higher torque than the SMC motor when both machines are designed to operate with the same temperature, though the torque density in terms of volume of SMC motor is higher than the laminated motor. In all cases, the machines are designed to fit into the same frame. A cost comparison has been presented between the SMC and laminated motors, which proves that the SMC motors can be manufactured much cheaper than the laminated motors. Also, SMC stator design presents axial magnet segmentation, optimal flux weakening, thermal analysis, stator stress analysis due to electromagnetic forces, and a rotor mechanical stress analysis.

Effect of rotor magnetic isolation dimensions on no‐load performance of ultra‐low speed high torque spoke type permanent magnet motor

AbstractThis study investigates the effects of rotor magnetic isolation dimensions on the no‐load performance of ultra‐low speed high torque spoke type permanent magnet motor. The studied spoke type permanent magnet motor structures are shown, where the rotor magnetic isolation parts include a magnetic barrier near the air gap (MB‐NAG), a magnetic barrier near the magnetic isolation sleeve (MB‐NMIS), a magnetic isolation sleeve (MIS). The magnetic circuit model is performed and the finite element analysis method is used to analyse the no‐load performance. Through analysing no‐load performance with three MB‐NAG shapes, the way to narrow the optimise dimension range considering reducing the cogging torque and increasing the back‐EMF synchronously is concluded. The results with different MB‐NMIS and MIS dimensions show that: (a) the optimised MB‐NMIS dimensions can increase the back‐EMF with a thin MIS in a certain dimension range of MB‐NMIS, and (b) the increasing proportion of back‐EMF influenced by the MB‐NMIS is inversely proportional to the thickness of MIS. The feasibility and effectiveness of the proposed motor structure and conclusion are experimentally verified.

Design and structural analysis of non-pneumatic tyres for different structures of polyurethane spokes

NPTs have vast applications because of no tyre puncture, no need for air pressure, low rolling resistance, and also have higher flexibility for design and recyclability. In this research work, different structures of polyurethane (PU) spokes have been designed and analyzed under radial loading conditions which include structures like honeycomb with varying cell angles, simple spoke, and trapezoid type by keeping in view that the cell wall thickness and somehow the mass of the structures remain the same. Based on the Mooney-Rivlin hyper-elastic material model and performing 2D non-linear static structural analysis on different types of NPTs using ANSYS, it has been observed that the simple spoke structure has the lowest spoke stress and deformation values of 2.01 MPa and 11.7 mm, while HC–A1 has the least value of strain energy of 2.58 mJ, at a load of 2500 N. The above results show that the straight spoke structures like simple spoke and trapezoid type have a high load-carrying ability than the honeycomb type NPTs under same boundary conditions. While honeycomb NPTs have higher fatigue life as compared to straight-spoke NPTs.

Anti-Notch 구조를 적용한 Spoke Type IPMSM의 출력 및 리플 개선 연구

This paper applied the Anti-Notch structure to the stator to improve the output and ripple of the spoke type IPMSM (Spoke type inner permanent magnet synchronous motor). Since the permanent magnet of the spoke type IPMSM is located in the radial direction, there is an advantage in that the magnetic flux in the air gap is concentrated and the power is increased. However, the Spoke type IPMSM has the disadvantage of lowering the output and generating noise and vibration because torque ripple and cogging torque are largely due to the magnetic resistance difference of the air gap. To improve this, the 2-D Finite Element Method (FEM) was used, and a design plan to improve output, torque ripple, and cogging torque according to the number of Anti-Notch was studied by applying the Anti-Notch structure to the stator of the existing designed model.

Leakage flux reduction of axial-flux switching PM machine by using HTS-disk

Nowadays, axial flux switching permanent magnet machines are attractive and widely used in direct drive applications because of their unique features. This paper proposes a high temperature superconductor (HTS) disk axial flux switching permanent magnet (AFSPM) machine with spoke type permanent magnets (PMs) and three-phase two layers concentrated windings. The novelty of the proposed machine is using HTS material on the rotor and stator as a disk, insignificant relative permeability of the HTS materials causes magnetic reluctance to become extreme. Because of this feature HTS-Disk in the proposed HTS-AFSPM machine does not allow the flux to enter or exit which causes leakage flux reduces. In order to better investigate and fair comparison, all analyses have done at the same condition using the finite element method (FEM) by Ansys Maxwell. The comparison results show that the proposed HTS-Disk AFSPM machine achieves higher back-EMF, permanent magnet (PM) flux, flux distribution, lower inductance and losses and fewer total harmonics distribution compared to conventional AFSPM machine.

Design of Concentrated Flux Synchronous Motor with Ferrite Magnet Considering Mechanical Stress at High Speed

This paper proposes a design of 90 kW concentrated flux synchronous motor (CFSM). A ferrite magnet is used because of low price compared to rare-earth materials and this spoke type structure of motor can be an alternative to the interior permanent magnet synchronous motor (IPMSM) using NdFeB. However, a greater size of ferrite magnet is required to achieve the same torque as NdFeB is used, because the residual induction of ferrite is approximately one third of NdFeB. Consequently, the spoke type structure is applied to improve the torque density. In the design process, methods of deciding the stack length, stator diameter, rotor diameter, and the number of poles and slots are suggested. Series turns per phase are determined by applying back-electromotive force-inductance map (EL map) in the initial design. A response surface method is applied for the optimization. Furthermore, a structural analysis is also conducted to confirm the safety at high speed. Finally, test of CFSM is conducted for the verification.

Analysis of Electromagnetic and Vibration Characteristics of a Spoke Type PMBLDC Motor

Analysis of Electromagnetic and Vibration Characteristics of a Spoke Type PMBLDC Motor

A Novel Rotor Topology for High-Performance Fractional Slot Concentrated Winding Interior Permanent Magnet Machine

This article presents a finite-element-based, multiobjective design optimization study of the fractional-slot, concentrated wound, permanent magnet synchronous machine (FSCW PMSM). Design objectives included maximization of efficiency, minimization of cost and low ripple without sacrificing torque density and wide constant power speed range. A large-scale optimization study revealed that while a V-type rotor provides high torque density, a spoke-type rotor has the benefit of low torque ripple. Quest for a design that can combine the goodness of both V- and spoke type rotors for an FSCW stator has led to a novel interior permanent magnet rotor topology referred here as Y-type. The goals of achieving maximum efficiency, minimum cost and wide CPSR were also accomplished in the proposed Y-type FSCW IPMSM. For experimental verification purpose, three fully optimized rotors - V-, spoke- and Y-type were constructed for a 12-slot/10-pole FSCW stator. Extensive experimental tests were conducted on three machines for a detailed comparison study. It will be shown that the proposed Y-type FSCW IPMSM outperforms both V and spoke-type configurations. A scaled-up version of the Y-type FSCW IPMSM shown to have satisfied many of the Freeedomcar 2020 targets, which is promising for application in electric vehicles.

A Study on Stator Design for Electromagnetic Noise Reduction in Washing Machine Motor

Received:11 november 2020; Accepted: 27 December 2020; Published online: 05 April 2021
 Abstract : For low cost, spoke type ferrite magnet motors with small air gap are using to washing machine. At that time, a noise problem occurs, so a design to reduce the noise is required. In the washing machine, set noise increased due to the reduction of air gap of motor at high speed spin mode. Not only the overall noise, but also the harmonics noises are greatly increased at set. As a result of set noise test and noise analysis through finite elements method, a stator tooth shoe shape in which the magnetic flux changes rapidly is cause of noise. Its shape creates many harmonics of load torque. The harmonics component of the load torque increases the overall noise of the set. The harmonics noise of the set has a large correlation with radial force component as well as the torque ripple. Especially, it is found that the harmonics noise of the set is related to harmonics component of load torque and the harmonics component of the radial force at stator tooth. The noise is reduced by applying the new design of stator tooth shoe that can minimize the change in magnetic flux through the noise cause analysis. Through this research, the harmonics noise as well as overall noise are reduced at small airgap motor. Therefore, it is possible to develop cost reduction motor for washing machine.

Design and Optimization of a Joint Torque Sensor for Lightweight Robots

Force detection is an important indicator of a robot's interaction with the working environment. Therefore, accurate and sensitive torque sensor design and development are important. This study proposed a robot joint torque sensor design and optimization based on a strain gauge and through-hole spoke structure topology to detect the external force with high sensitivity and low noise. A through-hole spoke type with a novel inclination sensing surface (ISS) was proposed, and the optimization design improved the strain gauge placement position and focused stress arrangement. Three optimization objectives were desired to enhance the joint torque sensor sensitivity with guaranteed stiffness. A sensor signal processing circuit was also introduced to obtain low-noise output signal performance. The experimental results showed that the joint torque sensor had a high sensitivity of 1.65 mV/Nm before amplification. This sensor was compared with a previous study and a commercial torque sensor. The prototype torque sensor indicated high sensitivity and low error.

Utilization of outpatient eSanjeevani National Teleconsultation Service during COVID- 19 pandemic in a public healthcare institution in North India

To analyse the utilization of outpatient eSanjeevani Telemedicine Service during COVID pandemic in a public healthcare institution in North India by profiling the attributes of patients availing online video consultation in terms of gender, age, urban-rural, organ-system involvement, speciality of OPD service given and prescription analysis. This is a descriptive, cross sectional study done at Dr. Rajendra Prasad Govt. Medical College which served as a hub in a hub & spoke type model for rendering online OPD consultations; on a software platform “eSanjeevani” developed by Centre for Development of Advanced Computing (C-DAC) Mohali. Data from 206 audio+video based online tele-OPD consultations & their prescriptions were analysed. Out of a total 206, 114 (55%) were males and 92 (45%) were females. Mean ± S.D. age of patients was 42 ± 19.6 years. 146 (71%) connected from rural area and 60 (29%) from urban area. 38 (18%) patients required to be referred to the health-care centre and 46 (22%) patients required a review after blood biochemistry investigations. 76 (37%) were from district Kangra of Himachal Pradesh. The most common organ system involved was musculoskeletal system (19%) followed by skin (18.4%) and gastrointestinal system (16%). The most commonly prescribed class of drugs were NSAIDs & analgesics (36%) antimicrobials (23%) and antihistaminics (18%).Telemedicine is an innovative solution to many of the challenges posed by COVID-19 pandemic. It can help substantially in decreasing the OPD workload in hospitals & decreasing infection chances for both patients & hospital staff.

Performance Improvement of Dual Stator Axial Flux Spoke Type Permanent Magnet Vernier Machine

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.

Performance Enhancement of Line Start Permanent Magnet Synchronous Motor With a Special Consequent Pole Rotor

This paper presents the development of line start permanent magnet synchronous motor (LSPMSM) employing a special consequent pole rotor. The proposed rotor structure uses both circumferentially magnetized spoke shape and radially magnetized arc shape magnets. The combination of spoke and arc shape is arranged to provide consequent magnetic poles. This new rotor structure improves the motor performance and consumes less magnet volume. The time-stepping finite element analysis (FEA) is used to evaluate transient and steady state performances. Extensive simulation studies are performed to establish the supremacy of proposed rotor structure over benchmarked spoke and some other known rotor structures. For experimental validation, prototypes of machine are built using (a) proposed magnet configuration, and (b) spoke type configuration having circumferentially magnetized magnets which is used as baseline motor. Rigorous experimental studies are carried out and it is observed that the proposed structure offers 4% improvement in the full load efficiency over the benchmarked spoke rotor LSPMSM yet by saving 10% magnet volume. Further, it is observed that the performance of the proposed machine is enhanced for direct online (DOL) as well as variable frequency drive (VFD) fed supply operation.

3kW급 풍력발전기용 페라이트 스포크 회전자 형상 특성비교

Most of the generators and electric motors developed in recent years are synchronous machines using permanent magnets of rare earth. As the name suggests, rare earth permanent magnets are expensive because they have a small amount distributed on the earth. In addition, the price fluctuation is large because it is concentrated and mined in a specific region. Therefore, in recent years, research has been actively conducted on developing a generator using a low cost ferrite permanent magnet for stable supply and reduction of the price of the generator. Ferrite magnet has a low magnetic flux density compared to a rare earth permanent magnet, so a large amount of permanent magnet must be used. In particular, the generator rotor is made in the form of a spoke to insert a large amount of permanent magnets. There are three typical spoke type types. This paper compare three types of characteristics at the same size and the same output.