Search results for " Torque"
showing 10 items of 108 documents
Maximum Torque Per Ampere control algorithm for low saliency ratio interior permanent magnet synchronous motors
2017
This paper presents an investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs). In particular, this study was carried out on a small-power IPMSM with low salience ratio. Both control algorithms have been implemented in the Matlab/Simulink environment, obtaining promising results.
Tetragonal Heusler Compounds for Spintronics
2013
With respect to the requirements of spin torque transfer (STT) materials, one the most promising materials families are the tunable tetragonal Heusler compounds based on Mn2YZ (Y=Co,Fe,Ni,Rh,...; Z=Al, Ga, Sn). They form the inverse cubic Heusler structure with three distinct magnetic sublattices, which allows a fine tuning of the magnetic properties. Starting with the stoichiometric Mn3Ga compound, we explored the complete phase diagram of Mn3-xYxZ (Y=Co, Fe, Ni and Z=Ga ). All series exhibit thermally stable magnetic properties. As we demonstrate, Mn3-xFexGa series, which are tetragonal over the whole range of compositions, are good as hard magnets, whereas magnetically more weak Mn3-xNix…
Experimental comparison of two control algorithms for low-saliency ratio interior permanent magnet synchronous motors
2018
In this paper, an experimental investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs) is described, analyzed and discussed. This investigation was carried out on a small-power IPMSM with low saliency ratio. More in detail, after a previous simulation study, the control techniques have been experimentally implemented and validated through means of a dSPACE® rapid prototyping system. The performances of the two algorithms have been evaluated and compared, obtaining interesting results.
Parameter sensitivity of flux-linkage based sensorless control for permanent magnet synchronous motors
2017
Sensorless control can be utilized to reduce cost, size and total complexity of a motor drive or enhance reliability of the system. This paper first presents a sensorless control algorithm for a surface permanent-magnet synchronous motor (SPMSM) based on estimated flux linkages and stator currents. Within the algorithm, rotor position error can be predicted by comparing the estimated currents with measured stator currents. Performance of the sensorless control based on flux-linkages and the dependency of the algorithm on motor parameters is then numerically investigated via simulations. It is found from the investigation that the accuracy of the method depends on the motor working condition…
Adaptive-Gain Observers and Applications
2007
We distinguish two kinds of observers for nonlinear systems which are used by scientists and engineers: empirical observers and converging observers.
Direct Torque Control of a Small Wind Turbine with a Sliding-Mode Speed Controller
2016
In this paper. the method of direct torque control in the presence of a sliding-mode speed controller is proposed for a small wind turbine being used in water heating applications. This concept and control system design can be expanded to grid connected or off-grid applications. Direct torque control of electrical machines has shown several advantages including very fast dynamics torque control over field-oriented control. Moreover. the torque and flux controllers in the direct torque control algorithms are based on hvsteretic controllers which are nonlinear. In the presence of a sliding-mode speed control. a nonlinear control system can be constructed which is matched for AC/DC conversion …
Dynamics of Torque Teno virus plasma DNAemia in allogeneic stem cell transplant recipients
2017
Abstract Background Torque Teno virus (TTV) plasma DNA load directly correlate with the level of immunosuppresion in different clinical settings. It is uncertain whether this may be the case in allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). Objectives We characterized the dynamics of TTV DNAemia in patients undergoing T-cell replete allo-SCT. Study design Retrospective single-center observational study including 72 allo-HSCT patients. Plasma TTV DNA loads were quantified before initiating the conditioning regimen and at different time-points after transplant by real-time PCR. White blood cells (WBC) and absolute lymphocyte counts (ALC) were measured by flow cytometry.…
Assessment of prevalence and load of torquetenovirus viraemia in a large cohort of healthy blood donors.
2020
OBJECTIVES: Torquetenovirus (TTV) is an emerging marker of functional immune competence with the potential to predict transplant-related adverse events. A large-scale epidemiological study was performed to understand how basal values vary in healthy individuals according to age and gender.; METHODS: We tested plasma from 1017 healthy blood donors aged 18-69years. The presence and load of TTV were determined by a real-time PCR assay. A sub-cohort of 384 donors was tested for anti-cytomegalovirus IgG antibodies, and 100 participants were also tested for TTV viraemia on a paired whole blood sample.; RESULTS: The overall prevalence of TTV was 65% (657/1017) with a mean (±SD) growth of 5±4% ever…
Kinetics of torque teno virus DNA load in saliva and plasma following allogeneic hematopoietic stem cell transplantation
2018
Plasma torque teno virus (TTV) DNA load directly correlates with the degree of T-cell immune reconstitution early after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, the kinetics of oral TTV DNA shedding was examined to assess whether quantitation of TTV DNA load in saliva may either replace or complement that in plasma for predicting lymphocyte (ALC) reconstitution after engraftment. This prospective observational study enrolled 38 nonconsecutive allo-HSCT recipients. Saliva and plasma specimens were collected at baseline (pretransplant) and at around days +30, +50, and +90 after allo-HSCT. TTV DNA was quantitated in both specimen types by real-time PCR. ALCs were m…
Changes in isokinetic torque and muscular activity of elbow flexors muscles with age
2001
This study examined the influence of aging on torque-angular velocity relationships for elbow flexion and the corresponding muscular activity levels in order to target the mechanisms involved in the eccentric muscle action in older adults. Maximal constant angular torque (CAT) at 90 degrees was measured at different angular velocities for concentric (CON; 60, 120, 180, 240 degrees s(-1)), isometric (ISO) and eccentric (ECC; -60, -120 degrees s(-1)) elbow flexor muscle actions in older (OG; 6 females and 4 males, 64-82 years) and young adult subjects (YG; 6 females, 6 males, 19-24 years) on an isokinetic dynamometer. Myoelectrical activity was quantified on biceps and triceps muscles, using …