Motor Loss Research Articles

인공 신경망을 이용한 PMSM의 MTPA 운전점 개선

In order to minimize copper loss of Permanent Magnet Synchronous Motor(PMSM), Maximum Torque Per Ampere(MTPA) control is essential. The MTPA control method utilizing mathematical models requires accurate information of parameters, but it is difficult to perform an accurate MTPA because the parameters may vary with temperature and load. Therefore, this paper proposes the new MTPA control method using ADALINE(Adaptive Linear Neuron), one of the Artificial Neural Network(ANN). In the proposed method, the locus of the stator current relative to the dSUPγ/SUP -axis current is estimated using ADALINE, and the MTPA operating point is determined through the estimated locus. This method is resistant to fluctuations in motor parameters and is easy to implement.

In-vivo testing of a novel wireless intraspinal microstimulation interface for restoration of motor function following spinal cord injury.

Spinal cord injury causes a drastic loss in motor and sensory function. Intraspinal microstimulation (ISMS) is an electrical stimulation method developed for restoring motor function by activating the spinal networks below the level of injury. Current ISMS technology uses fine penetrating microwires to stimulate the ventral horn of the lumbar enlargement. The penetrating wires traverse the dura mater through a transdural conduit that connects to an implantable pulse generator. A wireless, fully intradural ISMS implant was developed to mitigate the potential complications associated with the transdural conduit, including tethering and leakage of cerebrospinal fluid. Two wireless floating microelectrode array (WFMA) devices were implanted in the lumbar enlargement of an adult domestic pig. Voltage transients were used to assess the electrochemical stability of the interface. Manual flexion and extension movements of the spine were performed to evaluate the mechanical stability of the interface. Post-mortem 9T MRI imaging was used to confirm the location of the electrodes. The WFMA-based ISMS interface successfully evoked extension and flexion movements of the hip joint. Stimulation thresholds remained stable following manual extension and flexion of the spine. The preliminary results demonstrate the surgical feasibility as well as the functionality of the proposed wireless ISMS system.

The role of the insula in chronic pain following spinal cord injury: A resting-state fMRI study.

Spinal cord injury (SCI) results in the loss of motor and sensory function from disconnections between efferent and afferent pathways. Most SCI patients are affected with chronic neuropathic pain, but there is a paucity of data concerning neuroplastic changes following SCI. Chronic pain disrupts default networks and is associated with abnormal insular connectivity. The posterior insula (PI) is associated with the degree of pain and intensity of pain. The anterior insula (AI) is related to signal changes. Comprehension of SCI pain mechanisms is essential to elucidate effective treatment options. This study examines the insular gyri functional connectivity (FC) of seven (five male, two female) SCI participants with moderate-severe chronic pain compared to 10 (fivemale, five female) healthy controls (HC). All subjects had 3-Tesla MRI performed and resting-state functional MRI (fMRI) was acquired. FC metrics were obtained from the comparisons of resting-state fMRI among our various groups. A seed-to-voxel analysis was pursued, encompassing six gyri of the insula. For multiple comparisons, a correction was applied with a significance level of p<.05. There were significant differences in FC of the insula between SCI participants with chronic pain compared with HC. In the SCI participants, there was hyperconnectivity of the AI and PI to the frontal pole. In addition, there was increased FC noted between the PI and the anterior cingulate cortex. Hyperconnectivity was also observed between the AI and the occipital cortex. These findings illustrate that there is a complex hyperconnectivity and modulation of pain pathways after traumatic SCI.

Analysis of losses in the high-speed PM BLDC motor with open slot stator core made of amorphous soft magnetic material

PurposeThe purpose of this paper is to verify results related to losses in the core of a brushless DC prototype motor, obtained using its computer FE models, by experimental tests on manufactured machines. The paper focuses on the comparison of losses in the core of a machine with a classical stator core made of an iron–silicon material (Fe–Si) and a new one made of a modern METGLAS material.Design/methodology/approachComputer models of the prototype motors were created using FEM. The designed machines were manufactured, and experimental tests were performed. To achieve high frequencies in rotating magnetic fields, motors with a stator to rotor pole ratio of 9/12 were built. Twin rotor approach was applied, as two identical rotors were built along the two geometrically identical stators made of different core materials.FindingsExperimental studies have shown the superiority of the METGLAS material over the classical Fe–Si material. Material parameters were measured directly on the prepared cores as library data used in the simulation may be incorrect due to technological processes during core production, which was also verified. Problems related to twin rotor approach have been identified. Solution to the problem has been suggested. Necessity of 3D FEM modelling was identified.Originality/valueThe main source of originality is that METGLAS material used in the prototype machines was developed and manufactured by the authors themselves. Original approach to core parameter evaluation based on simplified methodology has been suggested. Another original part is a simplified methodology applied to loss measurement during no-load test.

Multi-Targeting Neuroprotective Effects of Syzygium aromaticum Bud Extracts and Their Key Phytocompounds against Neurodegenerative Diseases.

Alzheimer's disease (AD) is a neurodegenerative disease that causes a gradual loss of normal motor and cognitive function. The complex AD pathophysiology involves various factors such as oxidative stress, neuroinflammation, amyloid-beta (Aβ) aggregation, disturbed neurotransmission, and apoptosis. The available drugs suffer from a range of side effects and are not able to cover different aspects of the disease. Therefore, finding a safer therapeutic approach that can affect multiple targets at a time is highly desirable. In the present study, the underlying neuroprotective mechanism of an important culinary spice, Syzygium aromaticum (Clove) extract, and major bioactive compounds were studied in hydrogen peroxide-induced oxidative stress in human neuroblastoma SH-SY5Y cell lines as a model. The extracts were subjected to GC-MS to identify important bioactive components. The extracts and key bio-actives reduced reactive oxygen species (ROS), restored mitochondrial membrane potential (MMP), and provided neuroprotection from H2O2-induced oxidative stress in cell-based assays due to the antioxidant action. They also reduced lipid peroxidation significantly and restored GSH content. Clove extracts have also displayed anti-acetylcholinesterase (AChE) activity, anti-glycation potential, and Aβ aggregation/fibrilization inhibition. The multitarget neuroprotective approach displayed by Clove makes it a potential candidate for AD drug development.

Loss Analysis of High-Speed Permanent Magnet Motor for Cordless Vacuum Cleaner

Compared with traditional permanent magnet motors, high-speed permanent magnet motors (HSPMM) have the advantages of fast dynamic response, high efficiency, high reliability, small size, etc. Therefore, HSPMM has been widely used in household and industrial fields, and the research on high-speed permanent magnet motors has become a hot spot in the motor industry. In this paper, the high-speed permanent magnet motor is applied to the cordless vacuum cleaner, and the calculation and analysis of the iron loss and copper loss of the high-speed permanent magnet motor are emphatically studied for the HSPMM used in the cordless vacuum cleaner.

Estimation of Magnetic Suspension Loss and Efficiency in a 30 000 r/min One-Axis Actively Positioned Single-Drive Bearingless Motor

This study estimates the axial magnetic suspension loss and efficiency of a one-axis actively positioned single-drive bearingless motor in the rotational speeds of 1000 to 30 000 r/min. Bearingless motors have the advantage of enhanced efficiency owing to the absence of friction loss caused by mechanical ball bearings. In this study, the input powers of a bearingless motor with radial passive magnetic suspension and that of a motor with ball bearings were measured. Moreover, the mechanical ball bearing loss was also measured. Furthermore, the axial magnetic suspension loss in the single-drive bearingless motor was estimated. The efficiencies of both test motors were compared. Additionally, the ratios of the axial magnetic suspension loss and the ball bearing loss with respect to their input powers were evaluated.

Aerodynamic design of wind turbine blade with second derivative of thickness distribution as constraint

In order to make more use of wind energy, large-scale wind turbine blade size is the trend of development. With the increasing of blade length, the design and manufacture of the structure with the requirements of safety and economy are faced with great challenges. It is most sensitive to the blade manufacturer to reduce the composite lamination and production cost as long as the stress and strain level of the structure is satisfied. Therefore, the ideal thickness distribution requires not only the thickness monotonically decrease along the radial direction, but also the concavity and convexity of the thickness distribution function are required to be constant. Based on the in-house design code SurroOpt and the momentum-blade theory method, an optimization design platform for wind turbine blades was established. A 400kW wind turbine blade design was carried out with the aim of maximizing the output power and the constraint of the second derivative of the thickness distribution. The results show that the concave-convex characteristic of thickness distribution function has not changed, which is beneficial to the structural design. The designed blades have been manufactured and installed for operation. For the whole device, the maximum coefficient of wind energy utilization (including the loss of motor and machinery) reaches 0.42, which is 2.4% higher than 0.41 of the same kind of products.

Battery-Free, Wireless, Cuff-Type, Multimodal Physical Sensor for Continuous Temperature and Strain Monitoring of Nerve.

Peripheral nerve injuries cause various disabilities related to loss of motor and sensory functions. The treatment of these injuries typically requires surgical operations for improving functional recovery of the nerve. However, capabilities for continuous nerve monitoring remain a challenge. Herein, a battery-free, wireless, cuff-type, implantable, multimodal physical sensing platform for continuous in vivo monitoring of temperature and strain from the injured nerve is introduced. The thin, soft temperature, and strain sensors wrapped around the nerve exhibit good sensitivity, excellent stability, high linearity, and minimum hysteresis in relevant ranges. In particular, the strain sensor integrated with circuits for temperature compensation provides reliable, accurate strain monitoring with negligible temperature dependence. The system enables power harvesting and data communication to wireless, multiple implanted devices wrapped around the nerve. Experimental evaluations, verified by numerical simulations, with animal tests, demonstrate the feasibility and stability of the sensor system, which has great potential for continuous in vivo nerve monitoring from an early stage to complete regeneration.

Inhibitory effect of parthenolide on peripheral nerve degeneration.

Traumatic axonal damage disrupts connections between neurons, leading to the loss of motor and sensory functions. Although damaged peripheral nerves can regenerate, recovery depends on the variety and severity of nerve damage. Thus, many phytochemicals have been studied for their ability to reduce peripheral nerve degeneration, and among them, Parthenolide (PTL), which is extracted from Feverfew has effects against production of free radicals, inflammation, and apoptosis. Thus, we conducted a study to investigate whether PTL has an inhibitory effect on peripheral nerve degeneration during peripheral nerve damage. To verify the effect of PTL on peripheral nerve degeneration process, a morphological comparison of peripheral nerves with and without PTL was performed. PTL significantly reduced the quantity of fragmented ovoid formations at 3DIV (days in vitro). Immunostaining for MBP revealed that the ratio of intact myelin sheaths increased significantly in sciatic nerve with PTL compared with absence of PTL at 3DIV. Furthermore, nerve fibers in the presence of PTL maintained the continuity of Neurofilament (NF) compared to those without at 3DIV. Immunostaining for LAMP1 and p75 NTR showed that the expression of LAMP1 and p75 NTR decreased in the nerve after PTL addition at 3DIV. Lastly, immunostaining for anti-Ki67 revealed that PTL inhibited Ki67 expression at 3DIV compared to without PTL. These results confirm that PTL inhibits peripheral nerve degenerative processes. PTL may be a good applicant to inhibit peripheral nerve degeneration. Our study examined the effect of Parthenolide in preventing degeneration of peripheral nerves by inhibiting the breakdown of peripheral axons and myelin, also inhibiting Schwann cell trans-dedifferentiation and proliferation.

A Fast Numerical Modeling Approach Based on Boundary Field Method for Calculating AC Losses in Superconducting Motors

To improve the computational efficiency of the numerical methods for calculating ac loss in HTS motor, a new method called ‘Boundary field method’ is proposed in this article. This method combines the strength of ANSYS and COMSOL, which can reduce the complexity of modeling and computation time. In this article, three finite-element method based models, as case studies, were developed for a 100-kW superconducting induction motor. Model A models entire motor in COMSOL using A-H formulation, considering nonlinear <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E–J</i> relationship of high temperature superconducting tapes, which can calculate ac loss of motor directly; Combining another two models: Model B (the same entire superconducting motor in ANSYS) and model C (only superconducting stator windings in COMSOL) can achieve new method for calculating ac loss. The AC loss calculation error between two methods for two-layer windings in one slot is 2.5% and 7%, respectively. These results conclude the effectiveness and accuracy of “boundary field method.” More importantly, the computation time reduces dramatically from 48 hours in Model A to only 2 hours for proposed approach. This accurate and computationally efficient new numerical modeling approach could be used to calculate ac loss in various types of superconducting applications in future.

Therapeutic potential of small extracellular vesicles derived from mesenchymal stem cells for spinal cord and nerve injury.

Neural diseases such as compressive, congenital, and traumatic injuries have diverse consequences, from benign mild sequelae to severe life-threatening conditions with associated losses of motor, sensory, and autonomic functions. Several approaches have been adopted to control neuroinflammatory cascades. Traditionally, mesenchymal stem cells (MSCs) have been regarded as therapeutic agents, as they possess growth factors and cytokines with potential anti-inflammatory and regenerative effects. However, several animal model studies have reported conflicting outcomes, and therefore, the role of MSCs as a regenerative source for the treatment of neural pathologies remains debatable. In addition, issues such as heterogeneity and ethical issues limited their use as therapeutic agents. To overcome the obstacles associated with the use of traditional agents, we explored the therapeutic potentials of extracellular vesicles (EVs), which contain nucleic acids, functional proteins, and bioactive lipids, and play crucial roles in immune response regulation, inflammation reduction, and cell-to-cell communication. EVs may surpass MSCs in size issue, immunogenicity, and response to the host environment. However, a comprehensive review is required on the therapeutic potential of EVs for the treatment of neural pathologies. In this review, we discuss the action mechanism of EVs, their potential for treating neural pathologies, and future perspectives regarding their clinical applications.

MULTIPLE SYSTEM ATROPHY: CASE OF ATYPICALPARKINSON WITH PARKINSON PREDOMINANT PRESENTATION AND PROGRESSIVE CEREBELLAR DEGENERATION WITH EXTRAPYRAMIDAL AND AUTONOMIC INVOLVEMENT

Multiple System Atrophy is a rapidly progressive neurodegenerative disease. Symptoms tend to appear in 50s and advance rapidly over the course of 5-10 years with progressive loss of motor and autonomic function.

Application of platelet-rich plasma in spinal surgery.

With the aging of the population and changes in lifestyle, the incidence of spine-related diseases is increasing, which has become a major global public health problem; this results in a huge economic burden on the family and society. Spinal diseases and complications can lead to loss of motor, sensory, and autonomic functions. Therefore, it is necessary to identify effective treatment strategies. Currently, the treatment of spine-related diseases includes conservative, surgical, and minimally invasive interventional therapies. However, these treatment methods have several drawbacks such as drug tolerance and dependence, adjacent spondylosis, secondary surgery, infection, nerve injury, dural rupture, nonunion, and pseudoarthrosis. Further, it is more challenging to promote the regeneration of the interstitial disc and restore its biomechanical properties. Therefore, clinicians urgently need to identify methods that can limit disease progression or cure diseases at the etiological level. Platelet-rich plasma (PRP), a platelet-rich form of plasma extracted from venous blood, is a blood-derived product. Alpha granules contain a large number of cytokines, such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor, platelet factor 4 (PF-4), insulin-like growth factor-1 (IGF-1), and transforming growth factor-β (TGF-β). These growth factors allow stem cell proliferation and angiogenesis, promote bone regeneration, improve the local microenvironment, and enhance tissue regeneration capacity and functional recovery. This review describes the application of PRP in the treatment of spine-related diseases and discusses the clinical application of PRP in spinal surgery.

Active temperature control of electric drivetrains for efficiency increase

Electric vehicle sales have accelerated in recent years due to a wider customer acceptance. However, the still limited driving range continues to be a barrier to purchase for many customers. To improve the driving range, it is particularly important to further reduce all losses in the powertrain. This applies in particular to the temperature-dependent motor and inverter losses. In this context, this paper presents a high-fidelity motor model based on MotorCAD and ANSYS Maxwell, which is thermally controlled using an economic Model Predictive Control (MPC) approach to reduce the temperature dependent losses. A detailed explanation of the high-fidelity motor model is given, followed by a system-level validation including the thermal system model. The setup is used to simulate three different cycles, namely a highway drive, a rural road drive, and a long urban drive. A comparison between the MPC, which actively controls the rotor, winding and the inverter junction temperature, and a rule-based strategy is used to analyse the motor-level losses in detail. While the total MPC savings system level are up to 2.86% at 35 °C ambient temperature, 0.82% of this is saved due to increased temperatures of the motor caused by reduced cooling while driving first highway and then into the city. For a pure highway cycle the motor savings increase up to 1.12%. One major outcome, which is enabled by the detailed modelling approach, is that the majority of those motor savings are originating from reduced ac-copper losses at elevated temperatures. The reason was found to be a lower magnet flux density and a higher winding resistance which both lead to less eddy current losses in the winding. Moreover, the inverter losses were reduced by cooling the inverter prior to acceleration from standstill. By using the NTC behaviour of the IGBTs in low current region, temperature-dependent savings of up to 0.56% were achieved.

Isolating Neurologic Deficits in Cervical Spondylotic Myelopathy: A Case-Controlled Study, Using the NIH Toolbox Motor Battery.

Patients with cervical spondylotic myelopathy (CSM) have motor impairments, including weakness, imbalance, and loss of dexterity. The reliable assessment of these symptoms is critical for treatment decisions. This study aimed to determine, for the first time, the use of the NIH Toolbox motor battery (NIHTBm) in the objective assessment of motor deficits in patients with CSM. Patients with symptoms and MRI evidence of CSM and age-matched healthy controls (HC), with no evidence of spinal disorder or surgery were included in this case-control study based on our inclusion and exclusion criteria. We performed motor tests, dexterity, gait speed, grip strength, and balance tests, using the NIHTBm in patients with CSM and HCs. Motor impairment rates were determined in patients with CSM based on the NIHTBm scores. We determined the association between NIHTBm scores and patient-reported outcome scores; patient-reported outcome measures (the modified Japanese Orthopedic Association [mJOA] and Nurick grade) to determine the association. One-way analysis of variance was used to analyze group differences and the Spearman rank correlation to determine the relationship between assessment scores. We enrolled 24 patients with CSM with a mean age (SD) of 57.96 (10.61) years and 24 age-matched HCs with a mean age (SD) of 53.17 (6.04) years in this study. Overall, we observed a significant decrease in the motor function T-scores mean (SD): dexterity 31.54 (14.82) vs 51.54 (9.72), grip strength 32.00 (17.47) vs 56.79 (8.46), balance 27.58 (16.65) vs 40.21 (6.35), and gait speed 0.64 (0.18) vs 0.99 (0.17) m/s, in patients with CSM compared with that in HCs. The lower extremity dysfunction scores on the NIHTBm, balance (ρ = -0.67) and gait speed (ρ = -0.62), were associated with higher Nurick grades. We observed a similar but weaker association with the Nurick grades and NIHTBm tests: dexterity (ρ = -0.49) and grip strength (ρ = -0.31) scores. The total motor mJOA showed a positive but weak association with NIHTBm scores, gait speed (ρ = 0.38), balance (ρ = 0.49), grip strength (ρ = 0.41), and dexterity (ρ = 0.45). Patients with CSM had significantly lower NIHTBm scores compared with HCs. The results from the NIHTBm are consistent with the clinical presentation of CSM showing patients have motor impairments in both upper and lower extremities. As a neurologic-specific scale, NIHTBm should be used in the evaluation and clinical management of patients with CSM.

Experimental and statistical analysis of the effects of punching and laser cutting methods on induction motor efficiency and total magnetic losses in silicon lamination sheets

In this study, M400-50A electrical steel laminations (ESLs) used in electrical machines were cut with punching and laser methods and the effect of these cutting methods on the efficiency and total losses of induction motors was investigated. ESLs were prepared by laser and punching cutting methods concerning an induction motor with a power of 5.5 kW. After the stator and rotor packages were created, processes such as winding, varnishing, and mechanical assembly were performed on the motors. It is prepared for motor efficiency (MEfficiency) and total magnetic losses (TLosses) tests according to the direct measurement method specified in the IEC 60034-2-1-1A standard. Four different frequencies (f: 50, 75, 100 and 125 Hz) and five different motor loading rates (MLoad: 25, 50, 75, 100 and 125%) were defined as independent variables in the tests. MEfficiency and TLosses values were measured as dependent variables. Plastic deformation and edge rounding were observed on the edges cut with punching and edge rounding and angled edge formation on the edges cut with the laser. The average surface roughness of the laser-cut edges was determined to be higher than the ESLs cut by punching. It was observed that TLosses increased while MEfficiency decreased with increasing frequency and MLoad value in motor tests. It was determined that the training, testing, and experimental data are quite compatible with each other and the R2 values are close to 1 in the statistical analyzes performed with ANN (Artificial neural network). In addition, it was specified that RMSE (Root mean square error) and MAPE (Mean absolute percentage error) values vary between 0.007 and 13.310% for each cutting method and mathematical models can be used to predict MEfficiency and TLosses with ANN.

Type I Alexander disease: Update and validation of the clinical evolution-based classification.

Alexander disease (AxD) is a rare progressive leukodystrophy caused by autosomal dominant mutations in the Glial Fibrillary Acidic Protein (GFAP) gene. Three main disease classifications are currently in use, the traditional one defined by the age of onset, and two other based on clinical features at onset and brain MRI findings. Recently, we proposed a new classification, which is based on taking into consideration not only the presenting features, but also data related to the clinical course. In this study, we tried to apply this modified classification system to the cases of pediatric-onset AxD described in literature. A literature review was conducted in PubMed for articles published between 1949 to date. Articles that reported no patient's medical history and the articles about Adult-onset AxD were excluded. We included patients with a confirmed diagnosis of pediatric-onset AxD and of whom information about age and symptoms at onset, developmental milestones and loss of motor and language skills was available. Clinical data from 205 patients affected with pediatric-onset AxD were retrospectively reviewed. Among these, we identified 65 patients, of whom we had enough information about the clinical course and developmental milestones, and we assessed their disease evolutionary trajectories over time. Our results confirm that patients with Type I AxD might be classified into four subgroups (Ia, Ib, Ic, Id) basing on follow up data. In fact, despite the great variability of phenotypes in AxD, there are some shared trajectories of the disease evolution over time.

Mitigation of supply current harmonics in fuzzy-logic based 3-phase induction motor

&lt;span lang="EN-US"&gt;A parallel active power filter is employed to enrich the quality of power in the power grid with non-linear loads. The induction motor drive requires better performance in many applications. The overall performance enhancement is performed by mitigating the delivery of current harmonics and related warmness losses in an induction motor. In this paper, comprehensive performance evaluation of a 3-phase induction motor is mentioned with fuzzy logic controller-based shunt active filter (SAF), and the outcomes are compared with proportional integral (PI) and proportional derivative controller (PID) controller. In this work, a new scheme of shunt active filters is connected at the supply side of the vertical speed indicator VSI fed induction motor. The simulation was performed by a fuzzy logic controller (FLC) based 3-&lt;/span&gt;&lt;span lang="EN-US"&gt;f&lt;/span&gt;&lt;span lang="EN-US"&gt; induction motor drive (IMD) using parallel SAF. Simulation result from MATLAB/Simulink software has been presented to understand the reduction in harmonics by introducing an active filter near the supply side. A fuzzy suitable judgment controller is brought on this work to develop the induction motor dynamic response. Analysis of the simulation outcomes, the usage of MATLAB/Simulink software program for the proposed FLC managed induction motor had been demonstrated and overall performance enhancement of induction motor was discussed.&lt;/span&gt;

A Fast and Accurate Loss Model of Converter-Fed Induction Motor in Central Air-Conditioning System

In the traditional optimization model of central air-conditioner, the loss model of converter-fed motor is very rough, resulting in a large amount of energy waste. In this paper, a new energy loss model of central air-conditioning system from power to client is proposed. In the establishment of the loss model, the characteristics of pump load and variable frequency speed regulation are fully considered, and the electromagnetic variables which are difficult to be collected are replaced by the motor speed which can be directly calculated, so that the motor loss model can be introduced into the optimization model of the central air-conditioning system. A 5.5 kW converter-fed induction motor is tested under different speeds and loads, and the two-dimensional (2-D) loss data were obtained. Then, one-dimensional data were extracted from the measured 2-D data combined with the load characteristics of the pump, and compared with the calculated values of the proposed model in this article. The results show that the proposed loss model is of good accuracy and versatility. Because the proposed analytical model only needs the variable of motor speed to accurately estimate the losses, it can be easily applied to the optimization of central air-conditioning system.