Torque Improvement Research Articles

Torque Improvement of Spoke-type Permanent Magnet Motor with Auxiliary Stator Using Harmonic Current Control Strategy

The spoke-type permanent magnet motor with auxiliary stator exhibits high torque performance owing to the flux focus effects. To further improve its torque density, this paper proposes a control method by using harmonic current strategy. Based on the theoretical analysis, a 3-D torque look-up table by dq-axis current and electrical angle is established with the aid of the finite element method (FEM). The maximum torque per ampere curve at each rotor position is identified and summarized to adequately indicate the relationship between torque and current amplitude of the motor. Through theoretical derivation, it is concluded that the minimum torque cost curve is the contour line of ∂Te/∂i <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which can be employed to identify the harmonic current for torque density improvement. Compared to traditional strategies, the proposed control strategy can increase torque density of forward and reverse torque by 1.22% and 1.40%, respectively. The experimental results verify the analysis and simulation results, as well as prove the effectiveness of the proposed strategy.

Effect of fuel injection timing on performance and emissions with a dedicated direct injector in a hydrogen engine

In this study, hydrogen fuel was injected directly into a cylinder using a prototype of a dedicated hydrogen direct injector (HDI). The effects of fuel injection timing and amount of hydrogen fuel injected on engine output performance and emissions (e.g., nitrogen oxides and carbon dioxide) were investigated by varying the fuel injection timing from before top dead center (BTDC) 190 crank angle degree (CAD) toward BTDC 60 CAD. Strategies for maximizing the engine’s output performance when an after-treatment system for nitrogen oxide removal catalysts is not used were assessed. When using the HDI, a torque improvement result (up to 35.9%) can be obtained even under the condition that the hydrogen supply pressure was half as low as compared to the case of using a gasoline direct injector for hydrogen fuel. Under the condition of retarded fuel injection timing, a locally rich mixture is formed to increase the emission of nitrogen oxides at a level of 50 ppm or higher. The engine oil is burned to affect the emission of carbon dioxide (CO2), which is proportional to the load.

Influence of squirrel cage induction rotor geometry in battery C-rating

An external rotor induction motor (ERIM) is designed to propel an electric two-wheeler with improved torque to current ratio. The torque of the optimized ERIM is significantly based on the rotor cage. The rotor’s specific permeance varies by varying the bar’s shape, increasing the motor’s torque. Likewise, maintaining the flux density below the saturation state keeps the current low. This research work proposes and studies various rotor bar shapes to improve the torque to current ratio of the motor. The proposed bars are optimized with finite element analysis (for rotor bar shape selection) and a metaheuristic approach (for rotor cage sizing). Improvement of torque to current ratio reduces the discharge C-rating of the battery, being the source for the ERIM structure.

Performance Analysis of Optimization Based FOC and DTC Methods for Three Phase Induction Motor

Three-phase induction motors are becoming increasingly utilized in industrial field due to their better efficiency and simple manufacture. The speed control of an induction motor is essential in a variety of applications, but it is difficult to control. This research analyses the three-phase induction motor’s performance using field-oriented control (FOC) and direct torque control (DTC) techniques. The major aim of this work is to provide a critical evaluation of developing a simple speed controller for induction motors with improving the performance of Induction Motor (IM). For controlling a motor, different optimization approaches are accessible; in this research, a Fuzzy Logic Controller (FLC) with Fractional Order Darwinian Particle Swarm Optimization (FODPSO) algorithm is presented to control the induction motor. The FOC and DTC are controlled using FODPSO, and their performance is compared to the traditional FOC and DTC technique. Each scheme had its own simulation model, and the results were compared using hardware experimental and MATLAB-Simulink. In terms of time domain specifications and torque improvement, the proposed technique surpasses the existing method.

RESULTADOS DA PLIOMETRIA SOBRE A FUNÇÃO MOTORA NOS MEMBROS INFERIORES DE FUTEBOLISTAS

ABSTRACT Introduction: Soccer is watched by hundreds of millions of fans worldwide, in more than 1.5 million teams and 300,000 clubs worldwide, by men and women, children and adults of all levels of expertise. Demanding high performance from its practitioners, achieved only with the strong scientific basis of its technicians by constantly updated research. Objective: Study the results of extensor strength training with plyometrics exercises on the motor function of soccer players' lower limbs. Methods: An experiment with 30 soccer players as research volunteers was performed by randomly dividing them into high load plyometric training group (PHL, 20% of body weight), low load plyometric training group (PLL, 10% of body weight), and control group (CON) for various physiological tests before and after training. Results: Lower limb muscle mass in the PHL group increased significantly; creatine kinase (CK) changes were not statistically significant; regarding isokinetic muscle strength performance, the PHL group showed a significant improvement in peak torque at 60°/s and 180°/s, while the PLL group obtained only a significant improvement at 180°/s. Conclusion: Plyometric exercise promoted a significant improvement in isokinetic muscle strength of the lower extremity of soccer players; its training with different weights did not cause muscle damage. A progressive training load is recommended for athletes with low muscle strength during the initial training phase. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Advanced Design Optimization of Switched Reluctance Motors for Torque Improvement Using Supervised Learning Algorithm

Advanced Design Optimization of Switched Reluctance Motors for Torque Improvement Using Supervised Learning Algorithm

Torque Improvement of Magnet-Assisted Wound Field Motor with Field Unit Type Rotor

Torque Improvement of Magnet-Assisted Wound Field Motor with Field Unit Type Rotor

A Discrete Linearization-Based Predictive Intelligence Technique for Direct Torque and Flux Control of Induction Motor Drive with Feedback Linearization

This article describes a linearization-based model predictive intelligence control (MPIC) approach incorporated with a feedback linearization (FBL)-based direct torque and flux control (DTFC) of induction motor (IM) drive. This FBL DTFC with MPIC is employed here to analyze the dynamic performance of the IM drive and is compared with the conventional MPIC-based DTFC technique. The intuitive FBL approach develops the decoupled components of torque and flux. Hence, the specific intuitive linearized model-based DTFC-SVM not only preserves all advantages of DTFC but also improves the transient response with a reduced settling time of 30 to 40% along with a substantial reduction in torque and flux ripple by around 78% and 68%, respectively. However, the stability problem to design such a controller is a significant issue, and therefore, it is examined by estimating that the control law is monotonically converging with time. Hence, the proposed solution is highly justifiable and flexible. This proposed controller-based feedback linearized drive is modeled and its dynamic response and robust performance are analyzed by using MATLAB/SIMULINK software as well as extensive experimental results. It is observed from the experimental result that there is a significant improvement in torque and flux ripple of around 78% and 67%, respectively.

Effect of Groove Size on Aerodynamic Performance of a Low Reynolds Number UAV Propeller (Part II)

Following on from the author's previous work on grooved propellers, numerical investigations are carried out on Applied Precision Composites Slow Flyer 10×7 propeller. Computational Fluid Dynamics is used to analyze the novel design. The grooved sections considered have a rectangular geometry measuring 0.1×0.3mm, 0.2×0.1mm, 0.2×0.2mm and 0.2×0.3mm which are placed at 0.09c, 0.17c, 0.32c and 0.42c from the leading edge. The results of the study showed that the presence of grooves modified the flow characteristics having only a negative impact on the thrust performance. However, the grooves improved the power performance due to torque reduction. The analysis of the KP results showed, in most models, the low torque relative to the baseline in the operational range of the low to medium advance ratio range. However, the improvement in torque did not improve the efficiency in all models.

Average torque improvement of BLDC motor in battery electric vehicle

Average torque improvement of BLDC motor in battery electric vehicle

Study of Performance Improvement of a Tracked Vehicle Engine with Hybrid Mode

This study deals with the effects on power and torque of a tracked automotive diesel vehicle under parallel hybrid mode(Internal Combustion Engine (ICE) and Electric System). A methodology is developed to assess the performance of the hybrid vehicle. The tractive force requirement of the vehicle to achieve maximum speed (0 to 65 km/h in 61s) is simulated and validated with available data in literature. The simulation with different hybrid configurations such as Electric Motor (EM) before transmission (Mode 1) and EM after transmission (Mode 2) is carried out for assessment of better performance of the hybrid system. The Degree of Hybridization (DoH) for enhanced power and torque output is analysed with inputs of different Electric Motor (EM) ratings(22 kW and 50 kW power with 72.5 N-m and 167 N-m of torque respectively) and the base ICE’s power (221 kW) and torque (1030 N-m). The analysis indicates that Power and torque of the hybrid system (ICE and 50kW EM) is significantly improved to 290 kW and 1274 N-m. The Power &amp;amp; Torque of the hybrid system with 22kW and 50kW EM in Mode 2 configuration (5th gear with ratio 4.24 : 1) could be enhanced by 22% and 38% power output improvement (11% and 24% Torque improvement) with 17.3% and 32.3% DoH respectively.

In-situ field induced enhancement of damping-like field and field-free switching in perpendicularly coupled Pt/Co and CoFeB bilayers sandwiched by an ultrathin PtMn/Ta layer

Field-free switching of perpendicular magnetization and improvement of spin-orbit torque (SOT) efficiency are the keys for SOT-based devices towards ultrafast and low-power memory and computing applications. In this letter, we investigated pulse current induced magnetization switching and its efficiency in perpendicularly coupled Pt/Co and CoFeB bilayers sandwiched by an ultrathin PtMn/Ta layer, prepared in the presence/absence of an in-plane in-situ field. It is found that both the SOT efficiency and field-free switching are enhanced by the presence of the in-situ field. Quantitative characterization indicates that the damping-like field, HDL, is boosted by an amount of up to 45%. The tilted spin texture at the Co/PtMn interface caused by the presence of the in-situ field may play a role on the enhancement of SOT efficiency and field-free switching. Our findings not only provide a promising approach for SOT efficiency enhancement but also offer a possible layer stack for the integration of a full magnetic tunnel junction (MTJ) for low power memory and computing.

Utilization of Natural Zeolites and Fly Ash (Coal) Mixture Physically Activated Using Furnace As A Pellet - shaped Air Filter To Increase Engine Torque, Tecumseh TD110. 4-Stroke Petrol Motor

An air filter made from a mixture of natural zeolite and coal fly ash can be used to remove nitrogen (N2) and moisture (H2O) in the air. This filter can produce oxygen-rich air (O2) flowing into the combustion chamber to increase the quality of the combustion process so that complete combustion occurs and improve engine torque. In this research the filter was made from a physically activated mixture of natural zeolite and fly ash through heating in a furnace for 1 hour with temperature variations (200oC, 250oC, 300oC, 350oC), mass variations (50%, 75%, 100%) and variations in the composition of Z100%:F0%, Z75%:F25%, Z50%:F50%, Z25%:F75%, Z0%:F100%. Tests were carried out using a 4-stroke gasoline engine of Tecumseh TD110 located in the Motor Bakar and Propulsion Laboratory of the Mechanical Engineering Department, University of Lampung. Test results show that the biggest improvement in torque occurs in using a filter composition of Z50%:F50%, namely by 28.41%. The followed filter of the composition of Z75%:F25% is as big as 28.31%. The activation temperature of 350oC can improve the torque by 35.08%.&#x0D;

Five-Phase Hybrid Single-/Double-Layer Fractional Slot-Winding PMSM for Torque Improvement Under Third Harmonic Current Injection Condition

A 60-slot/22-pole five-phase machine with hybrid single-/double-layer fractional slot winding is proposed to improve torque under third harmonic current injection condition. Design process of the proposed machine includes two steps of first combining two sets of 20-slot/22-pole machine windings and then shortening coil-pitch. Due to the special structure of the proposed machine, torque-contributing space harmonics in magnetomotive force (MMF) are improved, and redundant space harmonic in MMF which causes high eddy current loss in permanent magnets is suppressed. The proposed machine is evaluated under two modes of third harmonic current injection, namely constant rms and peak harmonic injection. Compared with 20-slot/22-pole machine, the proposed machine achieves higher torque and lower losses under both third harmonic current injection conditions. Besides, the performance of the proposed machine when injecting only the first or third harmonic current is also analyzed.

Isokinetic Muscle Strength in Elite Soccer Players 3 and 6 months After Anterior Cruciate Ligament Reconstruction.

Milutinović, A, Jakovljević, V, Dabović, M, Faude, O, Radovanović, D, and Stojanović, E. Isokinetic muscle strength in elite soccer players 3 months and 6 months after anterior cruciate ligament reconstruction. J Strength Cond Res 37(4): e297-e304, 2023-The aim of this study was to evaluate interlimb symmetry in quadriceps and hamstring peak torque of elite soccer players at 3 months (stage 1) and 6 months (stage 2) after anterior cruciate ligament (ACL) reconstruction. Eight male professional soccer players competing at the highest level across different European countries, who had undergone ACL reconstruction, participated in this study. All patients underwent a supervised physiotherapy program after surgery. Data analyses included the use of separate two-way repeated-measures analyses of variance and effect sizes. Although knee extensor and flexor strength of the non-injured limb was found to be relatively unaltered ( g = -0.10 to 0.00) between stage 1 and stage 2, comparisons across time points revealed moderate improvements in quadriceps peak torque ( p = 0.01, g = 0.52), hamstring peak torque ( p = 0.07, g = 0.51), and hamstring:quadriceps (H/Q) ratio ( p = 0.03, g = -0.68) of the injured leg, as well as small-large improvements in the quadriceps ( p = 0.004, g = 1.24) and hamstring limb symmetry index (LSI) ( p = 0.056, g = 0.41). A time-dependent moderate-large asymmetry observed at stage 1 between the injured and noninjured leg in quadriceps peak torque ( p < 0.001, g = -1.83), hamstring peak torque ( p = 0.157, g = -0.67), and the H:Q ratio ( p = 0.06, g = 1.01), as well as between the hamstring and quadriceps LSI ( p = 0.03, g = -0.74) was eliminated at stage 2 ( g = -0.31 to 0.42). Our findings indicate the importance of supervised and comprehensive therapy, as well as strength screening to assist in recovery aimed at optimizing identified strength deficits following ACL reconstruction.

Optimal pulse width modulation for permanent magnet synchronous motor drive with improved torque and thermal losses using pulse numbers

This paper utilises the concept of pulse numbers to provide a new optimal pulse width modulation strategy for permanent magnet synchronous motor operation. The benefits of traditional modulation systems are preserved, as is an improvement in torque and thermal loss reduction. The continuous modulation approaches' performance limitations are solved by separating the performance constraints based on the drives surface area. The rotating component, which is regulated through odd and even pulse numbers, is used to mimic torque and thermal losses. With increases to 20 rpm and 30 rpm speeds, the suggested methods boost the 6% to 8% line current. Thermal losses are reduced by 21° C to 23° C, and torque is improved by 2 to 4 Nm. The proposed system is implemented by creating a MATLAB model that ensures the theoretic concept.

On Torque Improvement by Current Harmonic Injection in Isotropic and Anisotropic Multiphase Machines

Multiphase machines give the possibility to increase the torque injecting and controlling current harmonics of different orders. This work investigates the current harmonic injection techniques for both isotropic and anisotropic machines. The proposed analysis shows that for anisotropic machines, both amplitudes and angles of the optimal current injection should not be predicted based on the back electromotive force only. An analytical model is used to assess the differences in terms of no load and load voltage spectra. Considering these differences, a current injection technique based on the harmonic content of the voltage waveforms is proposed. In addition, the analysis to determine the optimum amplitudes and angles to maximize the torque capability is carried out by means of finite-element analysis (FEA) and compared with the techniques based on the analytical model. The FEA is carried out for both surface permanent magnet and V-shaped interior permanent magnet (IPM) machines with dual-three-phase winding layouts and injecting the fifth harmonic of current. Finally, the proposed concept is validated via an experimental test on a dual-three-phase V-shaped IPM machine. The results show that current harmonic injection based on the voltage vectors is applicable for both isotropic and anisotropic machines with good accuracy.

Engine performance improvements through turbocharger matching and turbine design

AbstractIt is interesting to improve engine system performance with turbocharger technologies. In this study, a systematic simulation for engine and turbocharger matching to provide full utilization of the turbocharger potential and improve the engine performance without sacrificing the emission is developed. A velocity ratio concept was proposed to count the turbocharger performance impacts due to the diameter ratio of compressor and turbine wheels. A design of experiments was used to optimize the turbocharger and engine performance for different turbocharger factors. A better‐matched turbocharger was obtained. A multidisciplinary optimization method was used to design a mixed flow turbine wheel to reduce the turbine velocity ratio at peak efficiency and increase the overall turbocharger efficiency. Results showed that about 0.4% torque improvements and 1.2% reductions in the engine brake‐specific fuel consumption were obtained without making any other changes to the engine. This study demonstrated that systematic simulations for engine systems and considering turbocharger wheel diameter ratio effects could further improve the turbocharged engine system matching and the engine performance.

Gap balanced adjusted mechanical alignment versus measured resection mechanical alignment: a randomised controlled trial

IntroductionAlignment goals in total knee replacement (TKR) is a topical subject. This study compares the short-term functional outcomes and patient reported outcome measures (PROMs) of two philosophies for knee arthroplasty alignment: measured resection (MR) and an individualised alignment philosophy, with the tibia mechanically aligned and an instrumented gap balancer (GB) to align the femur in both flexion and extension.Patients and methods94 knees were enrolled in this randomised controlled trial. The surgical protocol used a MR technique for mechanical alignment or a GB technique for individualised alignment. Primary outcome was quadriceps strength. Secondary outcomes included validated functional tests and PROMs as well as patient satisfaction. Outcomes were assessed pre-operatively, at 6 weeks, 3, 6 and 12 months post-operatively.ResultsAt 12-month follow-up, there was no significant difference in the change from baseline mean quadriceps peak torque between the two groups (p = 0.988). Significant improvement in the change in range of motion (ROM) in the GB group compared to the MR group at 3 months (13° vs 6° p = 0.028) but this improvement was not significant at 1 year (20° vs 17° p = 0.21). The functional test of balance showed statistically significant improvement at 6 weeks (p = 0.03) in the GB group but this difference was not maintained. PROMs favoured the GB group, with the KOOS pain scoring statistically better (p ≤ 0.05) at 6 weeks, 3, 6 and 12 months.ConclusionsIndividualised alignment philosophy utilising a GB technique did not demonstrate an improvement in the primary outcome measure quadriceps peak torque. Improvement was seen in the GB group in PROM pain scores that was significant, both statistically and clinically, out to at least 1 year. Gains that were seen in functional assessment with GB, although significant at some time points, were no longer significant at 1 year and no difference was seen in quads strength. Compared to a MR technique, the individualised GB technique appears to confer some improvement in pain, ROM and some functional tests following TKR in the short-term.

Performance Improvement of the Hybrid Switch Reluctance Motor by Notching Method

Hybrid switch reluctance motors are the family of switch reluctance motors (SRMs) that attenuate the magnetic saturation and increase the air gap magnetic flux by exploiting permanent magnets. The permanent magnet auxiliary air gap flux can affect the average torque and ripple. Commonly, the torque ripples reduction comes with the average torque drop. In this paper, the torque ripple reduction and average torque improvement are achieved for a 6/10 pole hybrid switch reluctance motor by inserting two symmetrical notches on its rotor. Also, the lengths of magnet and rectangular notches are optimized by the finite element method and sensitivity analysis. The comparison of the optimized design with the initial one carried out by finite element proves the efficiency of the proposed model.