Magnet Motor Research Articles

Topology design method of flux barrier in IPM motor by means of genetic algorithm implemented by multistep procedure

This study derives a high performance flux barrier for an interior permanent magnet (IPM) motor using binary-based topology optimization (TO). TO has a higher degree of optimization than size or shape optimization. An IPM motor has many design parameters including the current phase angle, core shape of rotor and stator, and magnet position and shape. The flux barrier in an IPM motor plays a particularly important role, influencing several characteristics. We apply TO, using a multistep genetic algorithm, to the rotor core in order to determine a flux barrier with the highest torque performance.

Development of a micro-step voltage-fed actuator with a novel stepper motor for automobile AGS systems.

This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS) system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM) motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system.

Performance Assessment and Comparison of Two Types Linear Motors for Electromagnetic Catapult

Linear motors are strong candidates in electromagnetic launching technology for space-use. In this paper, two types linear motors, including parallel magnetic circuit linear permanent magnet brushless DC motor (PMC-LPMBDCM) and serial magnetic circuit linear permanent magnet brushless DC motor(SMC-LPMBDCM), have been presented for electromagnetic catapult. The rudimental configurations of these two-type of linear motors are researched respectively. Then the contrast of performance between PMC-LPMBDCM and SMC-LPMBDCM is investigated detailedly. The electromagnetic properties and thrust characteristics are researched by finite element analysis(FEA) and experiment. Simulated and measured results can provide useful references to select the suitable type of motor for electromagnetic catapult. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4027

Design of a six-speed transmission hub with an integrated brushless permanent-magnet motor used for electric bicycles

Purpose – The electric motor and multi-speed transmission hub are essential components for an electric bicycle. Traditionally, these two devices have been designed and manufactured independently. The purpose of this study is to propose a novel electromechanical device that artfully integrates an exterior-rotor brushless permanent-magnet (BLPM) motor into a transmission hub to become a compact structural assembly. Design/methodology/approach – A novel design that integrates a three-phase, 20-pole/18-slot exterior-rotor BLPM motor with a multi-speed transmission hub composed of a six-link, two-degrees-of-freedom (2-DOF) compound planetary gear train (PGT) is presented in this study to overcome inherent drawbacks of existing designs. An analytical approach, based on fundamental circuits, is developed to synthesize the clutching sequences and numbers of teeth of all gears of the PGT. Findings – The integrated device provides six forward speeds, including two underdrives, two direct drives, and two overdrives, as well as two drive modes: the motor-drive mode and the human-drive mode, for electric bicycles. The main feature of the proposed design is the spur gear teeth merged with the pole shoes of the stator to dramatically minimize the detent torque, which is an oscillatory torque that always induces vibration and acoustic noise of the BLPM motor. Originality/value – The gear teeth on the pole shoes of the stator provide functions not only for transmission, but also act as dummy slots for adjusting the magnetostatic field of the BLPM motor to effectively reduce the detent torque. The peak value of the detent torque of the integrated design is only 9 percent of the original BLPM motor with identical magnet properties and motor dimensions. Such a feature is contributive in suppressing the vibration and acoustic noise of the electric bicycle's BLPM motor. A BLPM motor rated at 310 W and 250 r/min for the integrated device is presented and analyzed by using the commercial finite-element package Ansoft/Maxwell 2D Field Simulator.

Analytical Treatment With Rigid-Elastic Vibration of Permanent Magnet Motors With Expanding Application to Cyclically Symmetric Power-Transmission Systems

The phasing effect of the slot/magnet combination on rigid-elastic vibration is addressed by incorporating the cyclic symmetry of permanent magnet (PM) motors. Expanding research is also carried out to achieve more general findings in rotary power-transmission systems widely available in practical engineering. To these aims, model-free analysis is used to deal with the effect via superposition treatment. The results imply that the vibration induced by temporal-spatial excitation can be classified into rotational, translational, and balanced modes, all of which have rigid and elastic vibrations having specific base and/or contaminated deflections, and the elastic vibration can be of the standing, forward traveling, and backward traveling waves. These modes can be suppressed or excited depending on whether particular algebraic relationships are satisfied by slot/magnet combination, excitation order, and base and contaminated wave numbers. Since the analysis is independent of any models, specified magnetic force, and rigid-elastic vibration, analytical results regarding the expected relationships can be naturally created due to the structural and force symmetries of the PM motors. Because of this, similar results can be found for other rotary systems basically consisting of a rotary rotor and a stationary stator both having equally-spaced features, apart from the PM motors, typically including the turbine machines having fluid field and planetary gears with a mechanical contact. As an engineering application, the proposed method can serve as a fundamental tool when predicting or even suppressing the possible excitations associated with particular vibration modes in the mechanical and electrical designs of the symmetric systems. The superposition effect and analytical predictions are verified by the finite element method and strict comparisons against those from disk-shaped structures in an existing study.

A New Type of a Magnetic Plane Motor Coupled Mechanical Vibration with Electromagnetic Force

This paper proposes a new magnetic plane motor capable of rotation by the resonance energy of double-cantilever beam model excited by an electromagnetic force. This magnetic plane motor has two double-cantilever models, and the rotational direction is able to change by changing of the vibration mode. Basic characteristics of a prototype for the magnetic plane motor, such as rotational speed, output torque and efficiency were determined experimentally. Experimental results demonstrated that the rotational speed of 8.1 rpm was obtained with output torque of 0.07 Ncm for the magnetic plane motor having double-cantilever model. The output torque characteristics of the magnetic plane motor with two double-cantilever models improved 200 percent compared with double-cantilever model.

DESIGN AND ANALYSIS OF PERMANENT MAGNET MOTOR WITH MOVABLE STATORS

Permanent-magnet motors are widely used in-wheel motors of electric vehicles and hybrid vehicles. Based on a movable stator design, this paper presents a new type permanent-magnet motor, whose torque can be adjusted in order to meet difierent driving requirements. The stator geometry is varied by means of changing movable stator positions. Accordingly, the air-gap length in permanent- magnet motors is changed so that torque can be adjusted. To derive an analytical model, Fourier series expansions are employed to formulate air-gap geometry variation. The analytical model is validated by flnite element numerical results. Concerning motor torque variation capability achieved in this study, the ratio of the largest vs. the smallest torque is 2.3.

Pharyngeal Stimulation in Head and Neck Cancer Patients with Dysphagia: Functional Outcomes and Transcranial Magnetic Stimulation Motor Evoked Potentials

Purpose: Head and neck cancer patients often experience swallowing disorders, impacting health and quality of life. This study examined effects of electrical stimulation to the pharynx on swallowing outcomes in post-surgical head and neck cancer patients. Methods: Swallowing was assessed using video fluoroscopy before, and 30 minutes after, a ten-minute application of electrical stimulation to the pharynx in five patients experiencing moderate-severe dysphagia. Corticopharyngeal motor projections were measured before and after stimulation of the pharynx using transcranial magnetic stimulation of motor cortex and measurements of motor evoked potentials (MEPs) in the striated muscle of the posterior pharyngeal wall. Results: Short-term changes in swallowing function were observed post-stimulation in: pharyngeal transit time, cricopharyngeal opening duration, total number of swallows, penetration/aspiration score, and duration of contact between the base of tongue and posterior pharyngeal wall. MEPs could not be measured in two participants. In the remaining participants, the MEP measures were not strongly associated with changes in observed swallowing function as has been found for neurogenic dysphagia. Conclusions: These findings indicated that somatosensory input, generated by electrical stimulation of the pharynx, changes swallowing function in head and neck cancer patients. These changes are not strongly correlated with alterations of corticopharyngeal excitability as previously observed in acutely dysphagic stroke patients.

Development of Magnetic Field Sensor and Motor Fault Monitoring Application

For the purpose of motor fault real-time monitoring, this research developed a nano-silicon ni- tride film based magnetic field (MF) sensor, and applied this sensor in MF detection of two common faults. Through experiment, it turned out that arc discharge and slot discharge occur in motor fault produce MF with certain laws. This result proved the feasibility of the sensor and sensing method in MF analysis, and revealed possibility of a new method in fault detection.

Propiospinal myoclonus at sleep onset (PSM) after spinal anesthesia in a patient with restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS): a case report

Introduction PMS is a rare disorder that consist of repetitive axial jerks arousing mainly during drowsiness preceding falling asleep. The last revision of the International Classification of Sleep Disorders (ICDS-2) has considered PMS into the apparently normal variants and unresolved issues. PMS have been occasionally reported to occur in idiopathic RLS. Our objetive is to expose the results of the study of a patient with RLS who started with axial jerks resembling PSM after spinal anesthesia. Materials and methods A 56-year-old woman had a 6-year history of uncomfortable sensations involving the legs and sometimes also the arms when sitting or laying down, worsening in bed and impending sleep. Her husband also reported frequent limb movements during sleep. In the last 2 years sudden jerks of her trunk and abdomen had additionally appeared during relaxed wakefulness. Apparently the axial jerks began immediately after spinal anesthesia for a left lower extremity orthopedic procedure. The patient underwent a clinical interview, physical and neurological examination, video electroencephalographic recording (VEEG), video-polysomnographic recording (VPS), jerk-related EEG-EMG back averaging, electroneurography (ENG), somatosensory-evoked potentials (SEPs), magnetic stimulation motor evoked potentials (TMS) and brain and spinal cord magnetic resonance imaging (MRI). Results VPS showed repetitive jerks with variable regularity during relaxed wakefulness, intra sleep wakefulness and even during light sleep involving axial and leg muscles. On the other hand, isolated PLMs during sleep involving both anterior tibial muscles were registered. Spinal cord MRI showed degenerative changes present in the lower cervical and lumbar spine without apparent medullar compromise. TMS however revealed a slight but significant delay of central conduction to left lower limb. Jerk – related EEG – EMG back- averaging did not disclose any preceding cortical potential. No significant findings were found in the rest of the tests. Conclusion From our knowledge this is the first description of PMS after spinal anesthesia in a patient with SPI and PLMS. The causal relationship remains unclear. Acknowledgements I must thank all the contributors: Dr. Fernandez – Torre and Dr. Orizaola Balaguer of the Neurophysiology Department. All medical staff, nurses and technicians of our Multidisciplinary Marques de Valdecilla Sleep Unit.

Application of ON/OFF method to new conceptual design of magnetic devices

Purpose – The purpose of the paper is to show that how a new magnetic circuit, which the paper could not imagined beforehand, may be obtained using a newly developed ON/OFF topology optimization method by applying it to the design of magnetic head and motor. Design/methodology/approach – ON/OFF optimization technique combined with finite element method. Findings – It is shown that 3-D topology optimization of SPT head, in which the recording head is increased and the leakage flux is decreased, is possible using the proposed method. The optimization of IPM motor with the minimum torque ripple and the maximum toque is also examined. Originality/value – 3-D ON/OFF optimization method applied to practical problems considering the nonlinearity and rotation of rotor, etc.

Assessment of calf muscle fatigue during submaximal exercise using transcranial magnetic stimulation versus transcutaneous motor nerve stimulation

Few studies have assessed the time-dependent response of fatigue (i.e., loss of force) during submaximal exercise without the use of maximum contractions. There is unexplored potential in the use of the superimposed muscle twitch (SIT), evoked by transcranial magnetic stimulation (TMS) or motor nerve stimulation (MNS), to assess fatigue during voluntary submaximal contractions. For the human triceps surae muscles, there are also no data on TMS-evoked twitches. To optimise the TMS stimulus for assessment of fatigue, we first tested the effects of TMS power (40, 55, 70, 85, 100% max) on SIT force during contractions (0-100% MVC in 10% increments) in six subjects. Then, we compared SIT responses (TMS and MNS) during submaximal contractions and MVCs (all at 60 s intervals) during a continuous protocol of intermittent contractions (30% MVC) consisting of consecutive 5 min periods of baseline, fatigue (ischaemia) and recovery. For TMS, SIT force increased as a diminishing function of TMS power (P < 0.05), the relationships between SIT force and the force of voluntary contraction at all TMS powers were parabolic, and SIT force was maximised at ~20-40% MVC. During intermittent contractions, MVC and SIT forces were stable during baseline, decreased similarly during ischaemia by 40-50% (P < 0.05), and recovered similarly to baseline values (P > 0.05) before the end of the protocol. TMS can be used to evoke twitches during submaximal contractions of the human calf muscle and, along with MNS, used to assess fatigue during submaximal exercise.

Considerations for Manufacturing and Experimental Validation of a PM, Tubular Motor for a Matrix Converter Driven Aerospace Application

This paper deals with the manufacturing and the experimental verification of a tubular, linear, permanent magnet (TLPM) motor. A brief re-cap regarding the design and optimization procedures of a high force density, TLPM motor, presented in previous papers is first given. The design includes a novel, thermal management technique that is implemented in order to improve the thermal performance and thus improve the force density performance of the machine. Manufacturing and assembly of tubular motors is traditionally difficult and costly, thus details of the manufacturing and assembly procedures adopted are presented. The TLPM motor is finally assembled on a dedicated aerospace drive rig fed through a matrix converter. Experimental validation is achieved and compared to the modeling results.

Effects of Structure Parameters on Performance of DSPM Motor

A novel flux switching external rotor doubly salient permanent magnet (DSPM) motor was researched. The two-dimensional model of the motor was established by Ansoft motor design software and the effects of air gap length and rotor pole arc on motor performance were discussed. The simulation results show that larger or smaller air gap length and rotor pole arc improve the torque ripple rate, but the increase of air gap length is helpful to enhance the overload capacity. The conclusions of this article have positive significance for improving the motor performance.

Optimization Analysis of Structure Parameters for External Rotor DSPM Motor

The external rotor doubly salient permanent magnet (DSPM) motor which included permanent magnet in the rotor tooth was designed. The two-dimensional model of the motor was established and several structure parameters were analyzed by Ansoft electromagnetic analysis software. The relationship of the structure parameters and the average electromagnetic torque and winding induction potential was obtained. The simulation results show that smaller or bigger stator yoke depth and the pole thickness is not good for the motor efficient operation.

Control of Permanent Magnetic Spherical Motor Based on Torque-Sharing Strategy

In permanent magnet spherical motor control system, in order to obtain control current of the stator winding, it is required to solve the generalized inverse of the torque matrix of high dimension, which increases the computational burden of the control system. To solve this problem, the torque-sharing strategy of double-pole structure of PMSM was discussed. The target torque was decomposed into the rotation torque and the tilting torque through comparing the torque component of different stator windings. The set of control winding is divided. Further, according to the torque characteristics of a collection of internal stator winding and rotor position, an energizing strategy of the windings was developed, and the rotation and tilt torque control matrix were obtained, and two dimensional reduction matrixes reduced the computational burden. On this basis, the dynamics model and electrical model of PMSM were established, and the control system consisted of position loop and current loop. Control torque was obtained by the calculation of the torque method, and control current was obtained by torque-sharing strategy. Simulation results show that the system is able to achieve independent control of rotation and tilt and track the desired trajectory.

Sliding Mode Controller Based on Fuzzy Neural Network Optimization for FSPM

A sliding mode controller for flux-switching permanent magnet (FSPM) motor is investigated in this paper, in which direct torque control (DTC) concept, variable structure control are integrated to achieve high performance. Then, an FNN is investigated to optimize the control gain matrix of sliding mode controller. The theoretical analyses for the proposed FNN sliding-mode controller are described in detail. Simulation results show that the proposed FNN sliding-mode controller provides low torque ripple and the chattering phenomenon is much reduced.

Characteristics analysis of IPM motor applied by voltage source using 3‐D finite element method with prismatic elements

PurposeThe purpose of this paper is to clarify the usefulness of characteristics analysis of an interior permanent magnet (IPM) motor using the 3‐D finite element method (FEM) with prismatic elements from the view point of the accuracy and the calculation time.Design/methodology/approachThe authors analyzed characteristics of an IPM motor applied by the pulse width modulation (PWM) voltage source using the 3‐D FEM with prismatic elements and with tetrahedral elements; then compared the calculated results and the calculation time using prismatic elements with those using tetrahedral elements.FindingsIt was found that the calculated current and torque, and eddy current loss using prismatic elements are almost the same as those using tetrahedral elements. The calculation time using prismatic elements is shorter than that using tetrahedral elements.Originality/valueThis paper verifies the usefulness of the 3‐D FEM with prismatic elements through characteristics analysis of an IPM motor driven by the PWM voltage source.

A study on oscillatory and effective torques of an line-start PM motor in start-up operation

In this paper, various effective and oscillatory torque components in a line-start permanent magnet (LSPM) motor are analyzed using the principle of superposition through the analytic approach with an equivalent circuit. According to the independent sources, in the asynchronous speed the induced rotor current and braking stator current are derived by using the DQ equivalent circuit and Laplace transformation. Then, two effective components and three oscillatory components of torque are calculated quantitatively by using the analytic torque equations. Finally, to check usefulness of the proposed method, the current and torque characteristics are compared with finite element analysis and measurement results for various speeds.

Investigation on the performance of the single-phase LSPM motor for variable capacity type compressor

This paper investigates the performance of the line start permanent magnet (LSPM) motor which needs a high efficiency characteristic in a wide operation region. LSPM motor's performance indexes, such as efficiency, motor current, load angle and synchronous torque, have complex relationship with each other according to the main and auxiliary windings distribution, and the selection of running capacitor. The output characteristics can be defined by the winding structure which is calculated by d-q equivalent circuit and finite element method. The efficiency characteristic is verified by simulation as well as by experiment on the designed LSPM motor. From the results, we show that the redesigned model considering the winding structure and capacitor matching has a wide operating region.