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Experimental investigations of three-dimensional dynamic stall on a four-bladed Mach-scaled semielastic rotor with an innovative double-swept rotor blade planform are presented. The study focuses on the coupling between the aeroelastic behavior of the blade and the underlying aerodynamics. Blade bending moment and flap displacement measurements were conducted using strain gauges and optical tracking of blade tip markers. The aerodynamic behavior was characterized by means of unsteady surface pressure measurements using unsteady pressure-sensitive paint (iPSP) across the outer 65% of the blade span and fast response pressure transducers at discrete locations. Different cyclic-pitch settings were investigated at a rotation frequency of frotor = 23.6 Hz that corresponds to blade tip Mach and Reynolds numbers of Mtip = 0.282– 0.285 and Retip = 5.84-5.95 ×10 5. The findings reveal a detailed insight into the nonlinear behavior in the flap movement during downstroke. iPSP and pressure transducer data indicate that this nonlinear flap behavior is caused by a radially phase-shifted dynamic stall process at the forward and backward swept part of the blade.

This research presents a comparative analysis of two broken rotor bar (BRB) fault identification techniques for closed-loop induction motors (IMs). Both motor current signal analysis and Hilbert transform (HT) rely on spectrum analysis by means of fast fourier transform (FFT). Both approaches have shown their ability to identify BRBs under varying loads. In contrast, the HT is deemed more efficient than the motor current signature analysis (MCSA) approach when the motor is working without load. To maintain a high-performance speed control and to compensate for BRBs effect on the mechanical speed, the approach of control used is direct torque control (DTC). Utilizing a real-time implementation in MATLAB/Simulink with the real-time interface (RTI) based on the dSPACE 1104 board, the efficacy of the two techniques was evaluated.

ロケット用ターボポンプは、推進剤を液体ロケットエンジンの燃焼室に供給するための高速回転・高出力の回転機械である。そのため、過去の開発において様々な軸振動問題を経験してきた。軸シールで生じるロータダイナミック流体力は、ターボポンプロータ全体の軸振動特性に影響を与える。ロケット用ターボポンプによく使用されるフローティングリングシールは、ロータ振動を安定化させる作用を持つことが報告されている。一方、ターボポンプロータの要素配列もまた、軸振動特性に影響を与える。本研究では、ロータの要素配列と軸シールの位置関係が軸振動特性に与える影響を、複素固有値解析を用いて調べた。フローティングリングシーㇽのロータダイナミック流体力は連成剛性を用いてモデル化した。解析の結果、フローティングリングシーㇽの連成剛性は要素配列パターンによってはモード減衰比の改善効果があることが分かった。また、ターボポンプロータに対して、軸振動の安定化効果を得やすいフローティングリングシーㇽの設置について示した。, A rocket turbopump is a high-speed and high-power turbomachinery to feed the propellant into the combustion chamber of a liquid rocket engine. Therefore, various problems of turbopump rotor vibration had occurred in the past development. The Rotordynamic fluid force generated by the shaft seal is affects to the vibration characteristics of the turbopump rotor. It has been reported that the floating ring seal often applied to rocket turbopumps has a stabilizing effect on rotor vibration. On the other hand, component layout of the turbopump rotor also affects to the vibration characteristics. In this study, we investigate effects of the component layout and the shaft seal position on the rotor vibration characteristics by using complex eigenvalue analysis. The rotordynamic fluid force of the floating ring seal is modeled using the cross-coupled stiffness. The computational results showed that the cross-coupled stiffness of the floating ring seal is effective to improve the modal damping ratios in some component layout. In addition, the effective position of the floating ring seal on the turbopump rotor demonstrates the stabilization capability of the rotor vibration., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA2230012000, レポート番号: JAXA-RM-22-003

A number of transport vehicles have been fitted with electric traction motors and their inverters. The traction motor is required to continue to operate even if the inverter is under fault conditions. We propose a motor with two controllable rotors for a traction motor, which consists of 2 rotors and 1 stator. In this paper, we propose a fault-tolerant control method for a two-controllable-rotor motor using a 6-phase inverter. The operational principle of the two-controllable-rotor motor is described. The mathematical model under fault tolerant control is shown, and a fault-tolerant control method for the two-controllable-rotor motor is described. The proposed fault tolerant control method is verified by conducting finite element analysis and carrying out measurements on a prototype.

Vortex generators (VGs) in the form of small fins are attached to the blade of the H-rotor wind turbine to improve the performance. Many studies provide the utilization VGs both experimentally and numerically. However, the investigation of the full scale of counter-rotating VGs in rotor blades is still rarely found. In the current study, two shapes of VGs were investigated to evaluate wind turbine performance. VGs in rectangular and triangular shapes were attached under the identical blade geometry of 375 mm of chord length and the blade attachment of 30% from the chord length. VGs have a similar height and length of 6.5 mm and 13 mm, respectively. The turbine was constructed with three blades that rotate under 1,650 mm of the rotor diameter and 1,000 mm of rotor height. The chordwise position (x/c) of the VGs was at 10%, 15%, 20%, and 25%. The computational fluid dynamics with the unsteady Reynolds Average Navier Stokes (URANS) model were employed. We found that VGs behave in different performances. The rectangular VGs had the maximum power coefficient (Cp) value at the x/c of 20%, while the triangular VGs had the maximum Cp value at the x/c of 25%. However, both VGs show the maximum Cp in the value of 0.467 with a 1.5 Tip Speed Ratio. To evaluate the performance improvement, the blade with VGs was compared with the blade without VGs. It was found that using the VGs improved the performance of the wind turbine by around 45.68% and 47.24%, respectively, for triangular and rectangular shapes. The flow field characteristics in terms of turbulent kinetic energy and flow velocity were also presented in this study to gain a better understanding of how the VGs work. The result revealed that the presence of the VGs significantly improves the performance of the turbine.

In rotating machinery, the rotor mass unbalance will cause synchronous vibration, in which static unbalance will produce synchronous vibration force, and dynamic unbalance will produce synchronous vibration moment. In order to suppress the vibration moment of the magnetically suspended control moment gyro, a modified dual-channel notch filter (DNF) is proposed in this article. First, the modeling of the rotor system with mass unbalance is performed. Then, the design of modified DNF is carried out. This notch filter uses the equivalent vibration moment calculated by the current and displacement signals as input, and uses the orthogonal characteristics of the moment signals in the X and Y directions to enter the controller at the same time. The stability of the rotor system with a DNF is proven. Finally, the experimental results are given to show that this method can effectively eliminate the synchronous vibration moment in the rotor system.

Accurate and timely fault diagnosis of the rotating rectifier for a wound-rotor synchronous starter/generator is of great importance to improve system reliability. In the generation mode of the system, there is one idle stator winding of the main exciter. The terminal voltage characteristic of the idle stator winding is analyzed, and a novel fault diagnosis method for the rotating rectifier in the generation mode of the system is proposed. In this method, two feature voltages, namely, the maximum peak voltage and any other peak voltage of the idle stator winding terminal voltage are extracted through voltage sequence reconstruction to calculate the feature ratio for fault detection. The corresponding rotor position obtained by an inherent position sensor where the maximum peak voltage occurs is collected to determine the faulty diode location. The experimental results verify the feasibility and effectiveness of the proposed fault diagnosis method.

In this article, induction motor analysis of Tesla Model S was made firstly and then two materials for rotor bars analysis and comparison were made for induction motor of Tesla Model S. These material types of rotor bars are aluminium and copper. The advantages and disadvantages of two different materials for induction motor rotor bars of Tesla Model S were compared. Finally, evaluations and inferences were made with the analyzes and comparisons made., {"references":["Staton, D.A.; Goss, J. Open source electric motor models for commercial EV & Hybrid traction motors. Presented at Coil Winding, Insulation & Electrical Manufacturing Exhibition (CWIEME), Berlin, Germany, 20–22 June 2017.","M. Popescu, J. Goss, D. A. Staton, D. Hawkins, Y. C. Chong and A. Boglietti, \"Electrical Vehicles—Practical Solutions for Power Traction Motor Systems,\" in IEEE Transactions on Industry Applications, vol. 54, no. 3, pp. 2751-2762, May-June 2018.","H. Koke, \"Comparative study of stranded and bar windings in an induction motor for automotive propulsion applications.\", M.A.Sc thesis, McMaster University, Hamilton, Ontario, Canada, Aug. 2017.","Motor Design Limited, \"Tesla Model S 60 benchmarking overview_V2,\" Ricardo eStore, 2013. [Online]. Available: https://estore.ricardo.com/en/tesla-model-s-60-benchmarking-overview---c-23-c-70-p-244. [Accessed: 03-Sep-2022].","J. Goss, M. Popescu, D. Staton, D. Hawkins and A. Boglietti, \"Electrical vehicles - practical solutions for power traction drive systems,\" 2017 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD), 2017, pp. 80-88, doi: 10.1109/WEMDCD.2017.7947728.","E. Brocklehurst, \"Scrap metals and auto recycling commodity performance August 2021,\" Advanced Remarketing Services, 21-Feb-2022. [Online]. Available: https://ec2-34-193-100-78.compute 1.amazonaws.com/low-value-vehicle-outlook-july-2021-2/. [Accessed: 11-Nov-2022]."]}

The dynamic response of the rotor system in a ring die granulator is complex and difficult to solve when it operates under joint external, support and gear mesh forces. To solve this problem, a finite element method and extrusion theory was applied in this study to develop a dynamic coupling model for a hollow overhung rotor with external load excitation. A Newmark-β numerical integration method was used to solve for the dynamic response of the overhung rotor under multiple excitation forces. The results included time-domain response diagrams, frequency-domain response diagrams, phase diagrams, Poincaré section diagrams, and bifurcation diagrams. The model and the method were verified by testing a ring die granulator. On this basis, the dynamic response of the system is predicted according to the influence of different parameters. As the bearing support distance increased, the roller eccentricity decreased, the bearing clearance decreased, the response of the rotor system was significantly optimized, and the system tended to stabilize gradually. Therefore, this paper provides a theoretical basis and experimental verification for the optimization of a pelleting machine transmission structure.

The paper investigates the relative influence of the centroid of the three-phase squirrel cage induction motor rotor bar cross section, on the breakdown (maximum) torque of the machine. The influence of the angle of taper, the top width and the radial depth of the bar section, as established design variables, were also investigated so as to properly situate the degree of influence of the centroid, in comparison; as far as the maximum torque is concerned. The machines were investigated in their steady state operating mode using the equivalent circuit method. The machine learning capabilities of the Least Square Support Vector Machine (LSSVM) was deployed to extract by prediction, information about the likely dependencies between the randomized block of the geometric variables and the maximum torque, and the captured information was stored using the Root Mean Square Error (RMSE) of predictions. The validated results show that the rotor leakage reactance – a part determinant of the maximum torque; tends to show some significant sensitivity to a design change in the centroid of the transverse section of the rotor bar.

International audience; This paper studies the disturbance-observer-based adaptive neural network cooperative event-triggered control problem for six-rotor unmanned aerial vehicles with finite-time prescribed performance. Six-rotor unmanned aerial vehicle systems are divided into the position subsystem and the attitude subsystem. The switching threshold event-triggered mechanism that considers the influence of event triggering on the consensus control performance is designed of each six-rotor unmanned aerial vehicle to save the transmission resources, which excludes the Zeno behavior. Neural networks are introduced for estimating the uncertainties and solving the algebraic loop problem. In addition, for the position subsystem, by combining the prescribed performance with the velocity function, a finite-time control scheme is proposed, which can guarantee that the consensus errors converge to a prespecified neighborhood of the origin, and all closed-loop signals are bounded. Based on the designed control input signal of position subsystem, an adaptive neural network event-triggered control mechanism is designed to stabilize the attitude subsystem. Finally, some verification results are given to test the rationality of the proposed control strategy. —The purpose of this paper is to design an event-triggered cooperative control scheme to save the transmission resources for six-rotor unmanned aerial vehicle systems with performance limitations and lumped disturbances. In practical applications, if the impact of the event-triggered mechanism on the system performance is not taken into account, the system performance may be significantly degraded while the information transmission resource is saved. Thus, this paper designs an event-triggered mechanism that considers the system performance, which can effectively weigh the relationship between system performance and transmission resource consumption and better meet the practical requirements. Moreover, a finite-time specified performance control strategy is introduced to avoid the problem of difficult determination of residual set and improve the transient-state and steady-state performances of unmanned aerial vehicle systems, which is more in line with the actual demand.

Numerous researchers as well as the vehicle industry are paying increasing attention to the switching reluctance motor (SRM) drive. Due to its specialized qualities, SRMs are commonly used in electric vehicle applications. The stator/rotor pole arc of an 8/6 SRM is included in this study's investigation of design principles and performance improvement for poles arcs variation. Several limitations for the stator/rotor pole arc angle are derived for the design principles. These concepts are addressed in the finite element (FE) analysis of SRM topological parameters used in conventional and optimization analysis. The stator/rotor polar arc is tuned for performance using a genetic algorithm (GA) in order to maximize torque and efficiency. An ideal solution is chosen when the optimization results are represented. The proposed method can increase the maximum and average torque with (27.24%, 35.98%, 49.42%, 60.14%), (12.59%, 45.19%, 47.87%, 48.92%) for speeds [900, 1500, 2250, 3000 (rpm)] respectively, As shown by the comparison between the conventional and optimal designs. As well as the efficiency is improved (0.35%, 0.61%, 1.08%, 1.28%) for speeds [900, 1500, 2250, 3000 (rpm)] respectively.

Multi-frequency (or harmonic) emissions and interactions are ongoing challenges for converter-dominated power systems. Consequently, multi-frequency models are introduced for power quality and harmonic stability studies. Rotor-Speed-Dependent (RSD) emissions from Type 3 Wind Turbines (WT) can lead to unexpected interactions. However, there are only a few specific studies on Type 3 WTs' emissions. Besides, the provided analyses have been only based on field measurements. In this paper, the uncertainties of the field measurements are demonstrated experimentally. This paper provides an experimental analysis of emissions in different parts of a Type 3 WT, including stator, rotor, grid-side converter, and DC-link. In this way, theoretical emission patterns are formulated in sequence domain and verified by experimental measurements from a 2.2 MVA Type 3 WT tested by a 15 MVA grid emulator. The tests include emission measurements in different rotor speeds with identical output power set-point. To the best of our knowledge, the provided experiments are unique presentations from different parts of a Type 3 WT using MVA-scale torque and grid emulators. The test results provide a good impression of the existence, patterns, and amplitudes of the RSD emissions. Addressing such emissions in multi-frequency models can be necessary for the improvement of harmonic studies.

In the decoupling control process of the outer rotor coreless bearingless permanent magnet synchronous motor using least square support vector machine, the kernel width 2 and penalty factor of the least square support vector machine are difficult to tune, resulting in high kernel space complexity and low fitting accuracy. A new improved genetic algorithm is used to optimize the above parameters. Firstly, the generalized inverse system model of the original nonlinear multiple input output system is fitted online with the optimized least square support vector machine, and the generalized inverse system model is connected in series with the original system to form a pseudo-linear system. And then a linear closed-loop controller is used for control. Simulations and experiments show that the robustness and wide applicability of the original system are guaranteed. The dynamic and static performance of the system are improved, verifying the effectiveness of the scheme.

Using the embedded onboard digital thermal model is an economical and effective way to monitor the rotor temperatures of the electric vehicle (EV) propulsion Permanent Magnet Synchronous Motor (PMSM) in real-time. The onboard thermal model is generally in an analytical form with constant thermal resistances. However, in practical situations, the thermal convection intensities on the surfaces of the air gap and the end-cavity vary significantly with the rotational speed, producing a non-negligible influence on the estimation accuracy of the onboard thermal model. Aiming at eliminating this error and improving the accuracy, this paper explores the variation of the airflow's aerodynamics characteristics and the heat convection with the rotational speed through a syncretic study of theoretical, experimental, and numerical methods. It is found that the changing trend of the airflow presents a multi-stage characteristic in the speed range of 0–12, 000 rpm. The speed-dependent convective thermal resistances are formulaically parameterised and then used to replace the related constant thermal resistances in the thermal model. The standard vehicle driving cycle test result shows that this optimisation brings a nearly 11% reduction of the overall estimation error.

International audience; Single rotor-base unmanned aerial vehicles (UAVs) represent the most minimalistic design to implement an aerial vehicle. We describe here a mono-rotor UAV, also named mono-spinner, that uses torque modulation (also called swashplateless mechanism) to provide roll and pitch control without the need of a complicated swashplate mechanism. A full non-linear model of the mono-spinner based on the Euler-Poincaré theoretical framework is given including a description of the structure of the drone and its rotor control system. Mechanical properties, kinetic energy and all of the external forces of interest to derive the equations of motion are described. A novel, Lyapunov-stable, quaternion-based nonlinear control law based on the decomposition of the orientation quaternion into a spin component and a reduced orientation component is provided. Finally, simulation results based on parameters measured from a real implementation of a mono-spinner are produced.

This paper presents a new interior permanent magnet (IPM) rotor structure/ assembly which inherits from the Halbach magnet configuration and spoke-type IPM rotor to achieve a high saliency ratio and high torque/power density. A higher air-gap flux density and a higher saliency ratio are expected to improve torque density, while the rotor inner diameter can be maximized as much as possible to reduce core material consumption and increase internal space of the rotor. Accordingly, the electromagnetic performance of three motors consists of a unified stator but three different rotors, namely flux-concentrating rotor, Halbach array PM rotor and spoke-type IPM rotor is compared by finite element analysis (FEA). Due to the segmented structure of flux-concentrating PM rotor without magnetic bridges, the mechanical challenges are analyzed in detail for electric vehicle application. The stress analysis on the prototype design with fixing pins to hold the pole pieces validates the structural feasibility at 7200 r/min. Finally, a 72-slot/ 16-pole fractional-slot PM motor with new flux-concentrating rotor is manufactured and tested to verify its performance and feasibility. It can be concluded that the new rotor is superior to the spoke-type IPM and Halbach array PM rotor in terms of torque density and PM utilization.

Accurate rotor position estimation is important to ensure the high-performance operation of position sensorless permanent magnet synchronous motor (PMSM) drives. To suppress the estimated rotor position harmonic error (ERPHE) caused by inverter nonlinearities, flux spatial harmonics, and the current measurement error in high-frequency signal injection based schemes, an adaptive iterative learning control based online suppression method is proposed in this paper. This method constructs a P-type iterative learning rotor position observer with the forgetting factor to obtain the tracking error and generate the compensation value in real time. The stability, the convergence, and the parameter sensitivity of this observer are analyzed in detail. To improve the suppression effect of the ERPHE for different loads and speeds, an iterative learning gain self-tuning strategy is investigated. The proposed method does not require the offline detection and the discrimination of harmonic frequencies, which has strong suppression ability for different harmonic error components. The effectiveness is verified by experiments on a 2.2-kW interior PMSM drive platform.

This study investigates the implementation of the vortex particle method (VPM) with the goal of efficiently and accurately estimating the power performances and flow characteristics for a Savonius rotor. The accuracy and efficiency of simulation methods are critical for the reliable design of Savonius rotors. Among various approaches, VPM is chosen because it can be flexibly incorporated with self-correction techniques, and the distribution of bound vortex particles can effectively represent complex geometries. In this work, a double-trailing-edge-wake-modeling vortex particle method (DTVPM) is presented to extend the working range of VPM for dealing with large rotating amplitudes and high tip speed ratios (TSRs). DTVPM addresses asymmetrical torque predictions for a Savonius rotor without gap width. However, DTVPM performs poorly at high TSRs due to the absence of viscous effects near the surface. To capture complex wake structures, such as reverse flow structures, the viscous correction for tip vortices is suggested. The current research focuses on the implementation and validation of DTVPM for predicting torque coefficients and wake patterns, as well as comparisons to OpenFOAM results. Two-dimensional and incompressible flow is estimated at (Formula presented.) = 0.2–1.2. For the studied cases, a maximum power coefficient is obtained at (Formula presented.), consistent with published experimental data. In addition, the process of trailing-edge vortices generation and detachment is captured by DTVPM. The comparison results between OpenFOAM and DTVPM show that DTVPM allows to efficiently simulate a Savonius rotor without any empirical parameters. DTVPM will help to improve existing engineering models for wind energy fields.

In recent years, the crack fault is one of the most common faults in the rotor system and it is still a challenge for crack position diagnosis in the hollow shaft rotor system. In this paper, a method based on the Convolutional Neural Network and deep metric learning (CNN-C) is proposed to effectively identify the crack position for a hollow shaft rotor system. Center-loss function is used to enhance the performance of neural network. Main contributions include: Firstly, the dynamic response of the dual-disks hollow shaft rotor system is obtained. The analysis results show that the crack will cause super-harmonic resonance, and the peak value of it is closely related to the position and depth of the crack. In addition, the amplitude near the non-resonant region also has relationship with the crack parameters. Secondly, we proposed an effective crack position diagnosis method which has the highest 99.04% recognition accuracy compared with other algorithms. Then, the influence of penalty factor on CNN-C performance is analyzed, which shows that too high penalty factor will lead to the decline of the neural network performance. Finally, the feature vectors are visualized via t-distributed Stochastic Neighbor Embedding (t-SNE). Naive Bayes classifier (NB) and K-Nearest Neighbor algorithm (KNN) are used to verify the validity of the feature vectors extracted by CNN-C. The results show that NB and KNN have more regular decision boundaries and higher recognition accuracy on the feature vectors data set extracted by CNN-C, indicating that the feature vectors extracted by CNN-C have great intra-class compactness and inter-class separability.

The present work was based on an experimental study on the aerodynamic performance of a flapping wing rotor (FWR) and enhancement by passive pitching angle variation (PPAV) associated with powered flapping motion. The PPAV (in this study 10o~50o) was realized by a specially designed sleeve-pin unit as part of a U-shape flapping mechanism. Through experiment and analysis, it was found that the average lift produced by an FWR of PPAV was >100% higher than the baseline model, the same FWR of a constant pitching angle 30o under the same input power. It was also noted that the lift-voltage relationship for the FWR of PPAV was almost linear and the aerodynamic efficiency was also over 100% higher than the baseline FWR when the input voltage was under 6V. The aerodynamic lift or efficiency of the FWR of PPAV can be also increased significantly by reducing the weight of the wings. An FWR model was fabricated and achieved vertical take-off and free flight powered by 9V input voltage. The mechanism of PPAV function provides a feasible solution for aerodynamic improvement of a bio-inspired FWR and potential application to micro-air-vehicles (MAVs).

In this paper, a method of simultaneous sensorless rotor position and torque estimation is proposed for interior permanent magnet synchronous machines at standstill and low speed. The proposed method estimates the torque using high frequency inductances identified from the current variations due to high frequency square wave voltage injections in the estimated dq-axeswhich are simultaneously used for sensorless rotor position estimation. The proposed method is not dependent on the fundamental model and has taken the cross-coupling effect into consideration, allowing for low cost and fast torque estimation at standstill and low speed. Both simulations and experiments are carried out to verify the effectiveness of the proposed method.

Accurate predictions of the blade response in a multi-row compressor is one of the most important tasks within the design process of compressor blades. Some recent studies have shown that the decoupled method considering only the stator disturbances cannot obtain accurate results for cases with strong rotor–stator interactions, especially for the interaction between the rotor and downstream stator, and the coupled method with multi-row configurations is necessary. Factors determine what computational domains to model need to be clarified to find a balance between accuracy requirements and computational costs. To this end, this study conducted full-annulus unsteady calculations with decoupled and coupled configurations to investigate the forced response of an embedded compressor rotor induced by upstream and downstream stator disturbances and rotor–stator interactions, respectively. The results show that the upstream IGV disturbances were dominated by the wake, and the IGV and S1 potential fields had little effect on the R1 response. Meanwhile, the IGV–R1 interactions and S1–R1 interactions were dominated by one cut-on mode, respectively. The comparisons of the blade vibration amplitude and the unsteady pressure field calculated by decoupled and coupled methods revealed the mechanism of the forced response, namely, for the R1 response induced by upstream aerodynamic disturbances, the dominant excitation source was the IGV wake, and the blade vibration amplitude can be predicted by the decoupled method. In terms of the response induced by downstream disturbances, the cut-on S1-R1-interaction mode was dominant and the use of the decoupled method without considering its influence will lead to an inaccurate prediction. This study concluded that the formation process of rotor–stator interactions was the key factor that determines whether the decoupled method or coupled method should be used, and analogized a process independent of the downstream stator disturbance. The results can provide a preliminary configuration for accurate and efficient blade response predictions and explain the reason why including downstream stator vanes is very important.

Wound rotor induction motors (WRIM) are widely used in a vast number of high output power industrial applications due to their capability of reaching high start torques while maintaining low inrush currents. Nonetheless, these machines are very prone to require early maintenance, and the possibility of presenting rotor winding asymmetry failures is high due to their more complex rotor circuit. Although some recent works have proposed techniques that overcome the drawbacks of conventional methods, an additional research effort for the development of alternative approaches able to enhance their performance and reliability is desirable. In this work, a new method for the diagnosis of rotor asymmetries in WRIM is presented. The proposed methodology is based on a feed-forward neural network (FFNN) feed by suitable fault severity indicators, which rely on the maximum energy density of higher order harmonics (amplified by the failure) at strategic regions of the time-frequency maps obtained from stray flux signals under startup transient. Experimental results for three different levels of rotor asymmetries in a 11 KW WRIM prove the reliability of the enhanced proposed system in comparison to conventional approaches that only rely on the main sideband fault-harmonic amplitudes.

In rotor dynamics, blades are normally modelled as a slender beam, in which elastic deformations are coupled with each other. To identify these coupling effects, new rigid-flexible structural model for helicopter rotor system is proposed in this paper. Finite rotations of the whole blade (on flapwise, lagwise, and torsional) are described as three global rigid degrees of freedom. The nonlinear deformation geometrics of the beam is built on geometrically exact beam theory. New expressions for blade strain energy, kinetic energy, and virtual work of various kinds of external forces are derived as functions of finite rotations and elastic deformations. To quantify the coupling characteristics, following the definition of coupling factor in electromagnetics, a new coupling factor between two modal components on each mode is introduced in modal analysis. Simulations show that the new structural model is highly capable of solving static and dynamic problems in rotor dynamic and the maximum deformation that moderate deformation beam theory can predict might be 15% of beam length. After the new coupling factor is applied to study structurally coupled characteristics of rotor blade, it can be concluded that closeness of natural frequencies likely indicates considerable coupling between corresponding DOFs in structure.

This research basically focuses on a technique to estimate speed and rotor position with enhanced performance. For this purpose numerous techniques including Sensorless methods were taken into account and new developments were also made. Some advanced methods were also introduced for this purpose along with their associated merits and demerits. This research includes detailed study of all the methods which can be used for the purpose of speed and rotor position estimation including back-EMF sensing method which was an obsolete technique. Some other methods which can be used for this purpose are position estimation by inductance and flux, back-EMF zero crossing and integration of voltage. But all these methods were obsolete and had disadvantages associated with them so in this research, the main aim is to utilize latest technique which can give accurate results and is also up to date. For this purpose Extended Kalman Filter is employed for the purpose of state estimation while PID controller is utilized to synchronize system state following the reference signal. The proposed solution will control the harmonic generated in speed and position of Brushless DC motor and ultimately performance of the motor will get improved.

The article is devoted to the use of Park’s vector method for operational control of the rotor condition of induction motors of traction and auxiliary drives of railway rolling stock. In the course of the analysis, it was established that in order to increase the reliability and efficiency of the operation of vehicles, it is necessary to improve and implement diagnostic systems for monitoring the current state of the most damaged elements of induction electric motors built into the drive. This paper presents the development of a new approach to monitoring the state of a squirrel-cage rotor, which is based on the use of Park’s vector approach. In the course of the research, the issue of taking into account the asymmetric power supply of the engine during the diagnostic period during industrial operation was solved, which affects the accuracy of determining the degree of damage to the rotor. On the basis of the conducted research, the algorithm of the module for diagnosing the state of the squirrel-cage rotor of an induction motor has been developed for practical use in the built-in on-board systems of vehicles, which allows us to determine the degree of damage and monitor the development of the rotor defect during operation, including in automated mode.

Rotors are a crucial component of VTOL(vertical take-off and landing) devices like unmanned aerial vehicles (UAVs) or helicopters, etc., By generating a rotational force, they create the necessary thrust to lift and maneuver the vehicle in the air. In recent years, there has been a growing emphasis on developing rotor designs that are more efficient and effective for eVTOL. This has led to the emergence of several unconventional swept rotor designs that can improve aerodynamic and aeroacoustic performance. The present thesis aims to investigate the impact of achieving a balanced sweep distribution across a rotor blade and how it affects aerodynamic performance. The study explores the potential benefits and drawbacks of unconventional swept rotor designs and compares their performance curves to traditional straight rotor designs. The investigation begins with an overview of rotor design criteria and literature on swept rotor designs. A comprehensive design and analysis of the aerodynamic performance of various rotor designs are conducted using NASA's OpenVSP and VSPAero, a low-fidelity solver that implements the Vortex lattice method. The results are then compared with wind tunnel experiments. Based on the load distribution analysis of multiple sweep designs, it is noted that swept rotors exhibit decreased performance at lower advance ratios. However, as the speed or advance ratio increases, the overall performance of swept rotors significantly improves. This conclusion is drawn from the load distribution data obtained for each blade of the rotors, and by comparing the figure of merit (FOM) of various designs. Master of Science Picture this: a sleek unmanned aerial vehicle (UAV) soaring through the air, its Propellers whirring efficiently and quietly. What makes this possible? The answer lies in the design of the rotors themselves. Rotors are critical components of UAVs, providing the necessary thrust to lift and maneuver the vehicle in the air. And with the growing demand for more efficient and effective eVTOLs (Vertical take-off and Landing) vehicles, unconventional swept rotor designs have emerged as game-changers in the industry. The present thesis delves into the impact and effects of Parametric swept designs on rotor aerodynamic performance. The study seeks to uncover the potential benefits and drawbacks of these designs and compare their performance curves to traditional straight rotor designs. The study starts by looking at how rotors are designed and what others have done with similar designs. Various rotor designs have been thoroughly examined in terms of their aerodynamic characteristics using NASA's OpenVSP and VSPaero, a low-fidelity solver that uses the Vortex lattice method. To verify the tools, this data are compared with wind tunnel tests. Due to its cheap computing cost, OpenVSP makes it possible to investigate these discoveries in an economical manner. According to the results, swept rotors perform better at higher speeds than conventional rotors.

Surface-mounted high-speed permanent magnet motors are known for their small size, high power factor, and reliable control and operation. However, these motors may have low mechanical strength and weak tensile strength in their rotor magnet, which necessitates the adoption of an external sleeve for protection. Currently, carbon fiber composite sleeves are garnering increasing attention for their durable and reliable protective capabilities. Despite the apparent benefits of carbon fiber composite protective sleeves, systematic research on the relevant parameters such as winding angle, fiber type, resin type, winding tension, and curing method is currently lacking in the literature for high-speed permanent magnet motors. In this context, this paper employs an innovative approach, utilizing the Taguchi method, the National Ordnance Laboratories (NOL) ring failure test, and a resin content test, to investigate the winding process parameters of carbon fiber composite protective sleeves for high-speed permanent magnet motors. The results indicate that the tensile strength of the composite sleeve with a winding angle of 45 and 30° is reduced by 20~25% compared with the sleeve with a pure hoop winding angle. The loss of strength caused by the manufacturing process accounts for 30%. When the wet winding tension is 130 N, the tensile and shear strength of the sleeve decreases by 13 and 12%, respectively, compared with that of 70 N. When the dry winding temperature rise rate is 3 min/°C, the strength of the sleeve decreases by 16% compared with that of 1 min/°C. For a small-thickness sleeve with a thickness of 1.5 mm, two-layer curing can increase the tensile strength of the sleeve, while three-layer curing or more can decrease the strength. By studying the process parameters of the sleeve, this article prepared a composite sleeve for a high-speed permanent magnet motor with a line speed of 200 m/s. This study provides a comprehensive analysis of the manufacturing process parameters of the rotor sleeve, which is helpful for the design and performance optimization of high-speed permanent magnet motors.

The aerodynamic interaction between the rotor and fuselage is an important consideration in relation to the drag performance prediction of helicopters. In this paper, based on dynamic patched-grid technology coupled with a three-dimensional N–S equation solver, a numerical study of the aerodynamic interaction effects between the rotor and fuselage on the aerodynamic performance and flow field of the fuselage of a light civil helicopter is carried out under the forward flight condition. The deterioration of the drag performance and the evolution of the flow field structure caused by the rotation of the blades are illustrated. Due to the aerodynamic interaction, the drag of the fuselage is increased by 124.1% while the cycle of drag fluctuation is observed in one full revolution of the rotor with a change in amplitude of ±20%. The comparative results between the rotor-off and rotor-on cases show that the aerodynamic interaction effects between the rotor and fuselage on the drag performance are mainly reflected in the influence of the backward-developing rotor wake on the flow field of the rear part of the fuselage. An additional afterbody vortices system is induced, leading to a large reverse pressure gradient on the rear surface of the helicopter, which contributes to an increase in the pressure drag.

In this paper, the tool-tip responses for ball end milling, due to the coupling effects of a flexible rotor-bearing system, are investigated numerically. The milling machine tool spindle is modelled as the flexible rotor-bearing system. The critical speeds, natural modes, and unbalance responses of the system are calculated by applying the generalized polynomial expansion method. This generalized polynomial expansion method expresses the displacement as a series formed by the product of generalized coordinates and axial coordinate polynomials. According to the dynamic cutting force obtained by some scholars in the past, combined with the characteristics of the flexible rotor, the dynamic response of the tool-tip for ball end milling is numerically analyzed. The responses, including time histories, orbits, and FFT diagrams, are plotted to analyze the dynamic behaviors of the tool-tip. The coupling effects of the flexible rotor-bearing system on the system for ball end milling are first studied using the generalized polynomial expansion method. Unlike previous studies, the natural frequency varies with spindle speed and which of the different modes are included in the tool-tip response depends mainly on the spindle speed. Thanks to the gyroscopic effect, the critical speeds and responses of tool-tips can be discussed with respect to various spindle speed and tool flutes. The natural modes are accurately determined, and will excite critical speeds for certain modes, including forward and backward modes, thereby significantly affecting tool-tip response. In addition, the cutting force component associated with the tool-tip response affects the rotor-bearing system parameters, complicating the issue. Milling at higher spindle speed (2160–19,950 rpm), an important new result is found that the tool-tip oscillates with the cutting-force frequency, accompanied by a longer period vibration of the first backward mode of the rotor-bearing system. It can also be seen from the frequency spectrum analysis that, as the spindle speed increases, the peak amplitude of the first backward mode becomes larger. Milling at lower spindle speed (960, 1320 rpm), the in-plane vibration trajectory of the tool-tip gradually expands outwards clockwise around the origin until a stable loop is reached. This is because only the first backward mode of the rotor-bearing system is excited. Considering the coupling effect of the rotor-bearing system to perform the vibration analysis of the milling machine system, the parameters of the system can be designed or the spindle speed can be selected to avoid severe vibration during machining.

This study aimed to evaluate the survival of the probiotic Lactobacillus fermentum when it is encapsulated in powdered macroemulsions to develop a probiotic product with low water activity. For this purpose, the effect of the rotational speed of the rotor-stator and the spray-drying process was assessed on the microorganism survival and physical properties of probiotic high-oleic palm oil (HOPO) emulsions and powders. Two Box–Behnken experimental designs were carried out: in the first one, for the effect of the macro emulsification process, the numerical factors were the amount of HOPO, the velocity of the rotor-stator, and time, while the factors for the second one, the drying process, were the amount of HOPO, inoculum, and the inlet temperature. It was found that the droplet size (ADS) and polydispersity index (PdI) were influenced by HOPO concentration and time, ζ-potential by HOPO concentration and velocity, and creaming index (CI) by speed and time of homogenization. Additionally, HOPO concentration affected bacterial survival; the viability was between 78–99% after emulsion preparation and 83–107% after seven days. The spray-drying process showed a similar viable cell count before and after the drying process, a reduction between 0.04 and 0.8 Log10 CFUg−1; the moisture varied between 2.4% and 3.7%, values highly acceptable for probiotic products. We concluded that encapsulation of L. fermentum in powdered macroemulsions at the conditions studied is effective in obtaining a functional food from HOPO with optimal physical and probiotic properties according to national legislation (>106 CFU mL−1 or g−1).

This paper presents and evaluates a dual rotor axial flux permanent magnet motor for electric aircraft applications. Several features, including grain oriented electrical steel (GOES), magnet segmentation, and wires with rectangular cross-sections, are used to improve torque density and efficiency. Rather than simply optimizing the motor by itself, this paper evaluates the tradeoffs between motor performance and its interfaces with the drive, thermal management system (TMS), and mechanical structure. This information can be used along with similar analyses of the drive, TMS, and structure to select a design that achieves the system-level optimal performance. The paper uses finite element simulations to characterize tradeoffs between active mass, efficiency, fundamental frequency, power factor, axial forces on the rotors, and cooling surface area. Several designs exceed 95% efficiency at takeoff with less than 8 kg of active mass. While high pole counts, a large outer radius, and short stator teeth tend to optimize the magnetic performance at takeoff, this can reduce cruise efficiency, reduce the surface area through which the TMS can extract heat, increase the fundamental frequency the drive must supply, and increase the structural mass required to support the rotors. Additionally, designs with 20 °C cooler magnets were simulated to evaluate the impact of a more effective TMS, but the improvements in magnetic performance were relatively small.

In this paper, a novel dual-rotor multiple-winding machine (DRMWM) is proposed for the continuous variable transmission (CVT) in hybrid electric vehicles (HEVs). First, a mathematical model of the proposed machine is constructed by using the harmonic modeling method (HMM). Then, on the basis of the magnetic field analysis, the operating principle of the DRMWM is deduced. By introducing multiple windings with two different working harmonics, namely the permanent magnet (PM) harmonics, and the magnetic gear (MG) harmonics, the proposed DRMWM can cope with various operating conditions of HEVs. To further obtain optimal performance, a finite element analysis (FEA) and multi-objective genetic algorithm II (MOGA-II) combined sequential optimization is carried out for the proposed DRMWM. The proposed optimization method is proven to be more computationally efficient compared to the global optimization method. Finally, a prototype is manufactured and tested in various operating modes. The results validate the simulation and analytical method predictions. Also, it proves that the proposed DRMWM is suitable to work as the CVT in HEVs.

This study mainly investigated the nonlinear vibration performance of a rotor-casing coupling system containing a bolted flange connection. The dynamic equations of the coupling system were developed while considering the radial stiffness of the bolted flange structure, which contained a spigot, squirrel cage with ball bearing, and rotor-casing coupling vibration. To study the influence of the disk casing fixed-point rubbing fault on the coupling system’s nonlinear dynamic performance, an analytical model of the nonlinear impact forces was established, which considered the contact and vibration responses of the rotor and casing. The frictional force was obtained based on the Coulomb friction law. The iterative analysis of motion equations was performed utilizing the Newmark method. Then, the nonlinear dynamic behaviors of the coupled systems were examined using data, including a bifurcation diagram, spectrum plot, greatest Lyapunov exponents, etc. The effects of rubbing fault on the dynamic properties of system were investigated in detail, indicating that there were various motion states, which were described as periodic, multi-periodic, and quasi-periodic motions. Comparing the simulation results, it was found that rubbing fault seriously affected the motion stability of the rotor system. Finally, by gathering and examining the vibration data set from a test platform for rotor-casings with bolted joints, the correctness of the numerical simulation findings was confirmed. Additionally, the results of the experimental investigation agreed with that of the simulation. The dynamic distinguishing characteristics that were noticed can be used as an indicator for determining whether the fixed-point rubbing fault between the rotor and casing has become worse.

When rotating at a high speed in a microscale flow field in confined spaces, rotors are subject to a complex flow due to the joint effect of the centrifugal force, hindering of the stationary cavity and the scale effect. In this paper, a rotor-stator-cavity (RSC) microscale flow field simulation model of liquid-floating rotor micro gyroscopes is built, which can be used to study the flow characteristics of fluids in confined spaces with different Reynolds numbers (Re) and gap-to-diameter ratios. The Reynolds stress model (RSM) is applied to solve the Reynolds averaged Navier–Stokes equation for the distribution laws of the mean flow, turbulence statistics and frictional resistance under different working conditions. The results show that as the Re increases, the rotational boundary layer gradually separates from the stationary boundary layer, and the local Re mainly affects the distribution of velocity at the stationary boundary, while the gap-to-diameter ratio mainly affects the distribution of velocity at the rotational boundary. The Reynolds stress is mainly distributed in boundary layers, and the Reynolds normal stress is slightly greater than the Reynolds shear stress. The turbulence is in the state of plane-strain limit. As the Re increases, the frictional resistance coefficient increases. When Re is within 104, the frictional resistance coefficient increases as the gap-to-diameter ratio decreases, while the frictional resistance coefficient drops to the minimum when the Re exceeds 105 and the gap-to-diameter ratio is 0.027. This study can enable a better understanding of the flow characteristics of microscale RSCs under different working conditions.

Vibrations impose negative impacts on the effectiveness and public acceptance of helicopters. Active rotors with trailing-edge flaps have been proved to be an effective way to actively eliminate helicopter vibrations. For the existing control algorithm based on offline system identification, the transfer functions of an active rotor under different flight conditions are pre-requisites to implement closed-loop vibration control. In this study, a three-bladed active rotor with improved trailing-edge flaps is designed, and wind-tunnel tests are conducted to identify the transfer functions of this active rotor using frequency sweep and phase sweep methods. The experimental results demonstrate that these transfer functions are insensitive to the variation of flight speeds: the amplitude of the transfer function varies slightly, while the phase delay almost remains unchanged. In addition, this finding is validated through closed-loop vibration control tests with the active rotor. The transfer function obtained from the hover test results is also applicable to closed-loop vibration control tests under the forward flight conditions. This will dramatically simplify the implementation and operation of an active rotor.

The crack-induced changes in the vertical transient response of a rotating shaft–disc system, Jeffcott rotor, are investigated for transverse crack detection. The crack is considered as a breathing crack. A novel breathing function is proposed, in which the partially open–closed crack breathing behavior is interpolated between the fully open and closed crack behaviors. The breathing crack excites superharmonic response components of the transient as well as the subharmonic components. A Hilbert–Huang transform based on an improved empirical mode decomposition algorithm is subsequently formulated to evaluate the time–frequency representation of the vertical transient response of the rotor to detect the crack. The results show that the proposed breathing function can effectively reduce the computational effort without sacrificing the accuracy of the crack breathing behavior in the presence of small cracks. It is shown that time–frequency representations based on an improved empirical mode decomposition algorithm can lead to the detection of smaller cracks compared with those based on the empirical mode decomposition algorithm.

Surge is one of the main factors affecting the stability of the centrifugal compressor. This article investigates surge disturbance suppression of active magnetic bearing (AMB)-rotor systems in magnetically suspension centrifugal compressors. An active disturbance control method is adopted to make the rotor stably levitate under surge disturbance. First, the dynamic model of the magnetic bearing rotor is established and simplified into a single-channel model. Second, a third-order linear extended state observer (LESO) and a linear active disturbance rejection controller are designed. The performance analysis of the controller shows that the estimation error accumulation of the observer is bounded and the estimation errors decrease with the increase of the observer bandwidth. Furthermore, the variable differential parameter added in the differential link of the controller can flexibly adjust the system damping. A method of tuning parameters for linear active disturbance rejection control (LADRC) is proposed to suppress surge disturbance while satisfying the stability of the system. Finally, the results of the experiment demonstrate that the proposed scheme is effective in suppressing the large-scale vibration effect of the surge disturbance on the rotor, and the magnetically suspended centrifugal compressor (MSCC) can run stably with low amplitude under the modified surge and mild surge.

How to achieve uniform mixing of highly viscous fluids with low energy consumption is a major industry demand and one of the hot spots of mixing research. A typical multistage rotor-stator mixer (MRSM) equipped with a distributor was investigated to disclose the effects on the mixing performance and power consumption for highly viscous fluids via numerical simulation, considering the influence factors associated with different geometric parameters of both MRSM and the distributor. The mixing index and power consumption are used to evaluate the performance of the mixers. The dimensionless correlations for the mixing index and the power consumption are established considering the factors including the flow rate, rotor speed, the number of mixing units. Adopting the optimized mixer with the distributor (X1-T1), the mixing index increases to 0.85 (obviously higher than 0.46 for the mixer T1 without a distributor), meanwhile the corresponding power consumption is about 1/5 of that of T1 achieving the same mixing effect. It illustrates that the distributor can significantly improve the mixing of highly viscous fluids in the MRSM without the cost of large power consumption. These results would provide a guidance on the design and optimization of multistage rotor-stator mixers in industrial applications.

One of the important components of the quality of food products is the quality of water used. A common way to remove unwanted impurities from water is aeration, i.e. the oxidation of chemical compounds in water by oxygen. Aeration devices with mechanical energy input in comparison with other groups of devices, namely with energy input with gas phase and with liquid phase, have low power consumption and additional mixing of the processed medium. The work presents a study of oxygen absorption in water in an experimental setup with rotor-pulsating apparatus for water treatment in beverage production technology. In this paper, the energy and technological parameters of aeration of a model aqueous solution of a certain concentration of sodium sulfide in an experimental setup with a rotor-pulsating apparatus as an aerator are determined. The experimental aeration setup allows conducting research in several modes and consists in particular of a vessel, a rotor-pulsating apparatus, two ejectors - one at the entrance to the rotor-pulsating, the other at the outlet, the recirculation pipeline. Air from the atmosphere enters each of the ejectors through a separate air duct. The aeration of the studied water took place in the recirculation mode for 20 minutes. Determination of the oxygen mass transfer rate is determined by the iodometric titration method on the rate of oxidation of sodium sulfite. Experiments were conducted without using a catalyst. It is determined that when placing the ejector unit at the rotorpulsating apparatus inlet at the angular rotor unit velocity of 240.02; 270.18, and 300.02 s-1, the oxygen mass transfer rate is 1.39; 1.49 and 1.73 kg m3 /h. At the location of the ejector unit at the outlet of the rotor-pulsating apparatus, the velocity of the oxygen mass transfer under the same conditions is 1.17; 1.36 and 1.63 kg m3 /h respectively. However, the power consumption of the second scheme exceeds the power consumption by the first scheme by 50%. Однією з важливих складових якості харчових продуктів є якість використовуваної води. Поширеним способом видалення з води небажаних домішок є аерація, тобто окиснення хімічних сполук у воді киснем повітря. Аераційні пристрої з механічним введенням енергії в порівнянні з іншими групами пристроїв, а саме з введенням енергії з газовою фазою, та з рідкою фазою, мають низьке енергоспоживання та додаткове перемішування середовища, що обробляється. У роботі представлено дослідження поглинання кисню водою на експериментальній установці з роторно-пульсаційним апаратом для обробки води в технології виробництва напоїв. У даній роботі визначено енергетичні та технологічні параметри аерації модельного водного розчину певної концентрації сульфіду натрію в експериментальній установці з роторно-пульсаційним апаратом в якості аератора. Експериментальна аераційна установка дозволяє проводити дослідження в декількох режимах та складається зокрема з посудини, роторно-пульсаційного апарата, двох ежекторів - один на вході в роторнопульсаційний апарат, інший – на виході), трубопроводу рециркуляції. Повітря з атмосфери надходить до кожного з ежекторів через окремий повітропровід. Аерація води, що досліджувалась, відбувалась в режимі рециркуляції протягом 20 хв. Визначення швидкості масообміну кисню визначають методом йодометричного титрування за швидкістю окислення сульфіту натрію. Експерименти проводили без використання каталізатора. Визначено, що при розміщенні ежекторного блоку на вході роторно-пульсаційного апарата при кутовій швидкості ротора 240,02; 270,18 і 300,02 с -1 , швидкість масообміну кисню 1,39; 1,49 і 1,73 кг м 3 /год. При розташуванні ежекторного блоку на виході з роторно-пульсаційного апарата швидкість масообміну кисню за тих же умов становить 1,17; 1,36 і 1,63 кг м 3 /год відповідно. Однак споживана потужність другої схеми перевищує споживану потужність першої схеми на 50%.

In this paper a complete methodology of modeling and control of quad-rotor aircraft is exposed. In fact, a PD on-line optimized Neural Networks Approach (PD-NN) is developed and applied to control the attitude of a quad-rotor that is evolving in hostile environment with wind gust disturbances and should maintain its position despite of these troubles. Whereas PD classical controllers are dedicated for the positions, altitude and speed control. The main objective of this work is to develop a smart Self-Tuning PD controller for attitude angles control, based on neural networks capable of controlling the quad-rotor for an optimized performance thus following a desired trajectory. Many problems could arise if the quad-rotor is evolving in hostile environments presenting irregular troubles such as wind gusts modeled and applied to the overall system. The quad-rotor has to rapidly achieve tasks while guaranteeing stability and precision and must behave quickly with regards to decision making fronting turbulences. This technique offers some advantages over conventional control methods such as PD controllers. Simulation results are achieved with the use of Matlab/Simulink environment and are established on a comparative study between PD and PD-NN controllers founded on wind disturbances application. These obstacles are applied with numerous degrees of strength to test the quad-rotor comportment. Experimental results are reached with the use of the V-REP environment with which some trajectories are tracked and then applied on a BLADE Inductrix FPV+. These simulations and experimental results are acceptable and have confirmed the efficiency of the proposed PD-NN approach. In fact, this controller has fairly smaller errors than the PD controller and has an improved ability to reject troubles. Moreover, it has confirmed to be extremely vigorous and efficient fronting disturbances in the form of wind disturbances.

It is recognized that the rotor with a shielding cylinder (SC) is one of the effective measures to restrain the rotor eddy current loss (RECL) for high-speed surface-mounted permanent magnet synchronous motors (PMSMs). At present, the RECL of PMSMs with multilayer composite rotor structure is mainly analyzed by the finite element method (FEM), which has obvious shortcomings in time-consumption and the mesh generation of the thin SC. In this paper, a multi-layer subdomain analytical model for calculating the RECL of high-speed PMSMs with both non-ferromagnetic retaining sleeve and SC is proposed by taking the effects of eddy current reaction, stator slotting and current harmonics into account. Moreover, the 3-D distribution coefficient of eddy current in the SC is derived by the equivalent impedance method and the effects of temperature on the conductivity of the SC and RECL are obtained through equivalent thermal network model. Based on the analytical model, the SC parameters are calculated to obtain the variation ranges when the RECL is minimum. Finally, the C-shape core experiment was built up to verify the correctness of the multilayer analytical model under different shielding layer conductivities and thicknesses.

In the docking process of aeroengine rotor parts, docking accuracy that indicates the gaps between the end faces is strictly required. A key issue is improving docking accuracy using automated docking equipment. In this paper, a systematic study is carried out on the error modeling and compensation of a novel six-degrees-of-freedom (6-DOF) docking equipment for aeroengine rotors. First, a new model for indicating the main indexes of docking accuracy is proposed. Then, the error model of a specially designed 6-DOF docking equipment is established based on a modified Denavit Hartenberg method with five parameters. Subsequently, two error compensation methods are proposed. Based on the above models, a docking accuracy simulation algorithm is proposed using the Monte Carlo method. Finally, verification experiments are conducted. The results show that, for the maximum values and standard deviations of the gaps between the rotor end-faces in the actual and target positions and attitudes, i.e., main indexes that represent docking accuracy, the deviation rates between the simulation and experimental results are less than 20%. The modeling methods have referential significance. The decline rates of these values are 50–65% when using the two proposed compensation methods. The compensation methods significantly improve the docking accuracy.

This article delves into the geometry-impedance relation of the three-phase squirrel cage induction motor (SCIM), to study the levels of sensitivity of the impedance parameters to design modifications in the geometry of the rotor bar cross section. Studies have long clarified the facts about the strong influence that the geometry of the rotor bar transverse section has on the standstill and operating impedance values of the rotor circuit, and it is a well-known fact that the development of electromagnetic torque as well as the shape of the torque-speed characteristic of the SCIM are all to a large extent dependent on the rotor circuit impedance. During design and optimization routines, the design engineer usually leverages on the aforementioned facts to accomplish a successful torque optimization program. Barring the saturation of the leakage flux path during large slip motoring operation, the magnitude of the rotor leakage reactance is usually greater than that of the rotor resistance, but the result of this study shows that the relative sensitivity of this reactance to design changes in the geometry of the rotor bar cross section, appears inferior. Keywords: Rotor bar, Rotor leakage reactance, Rotor resistance, Design, Torque, Sensitivity. Title: The Relative Sensitivity of Rotor Impedance Parameters to the Design Changes in Rotor Bar Geometry - A Torque Production perspective Author: Nelson Oyakhilomen Omogbai International Journal of Novel Research in Engineering and Science ISSN 2394-7349 Vol. 9, Issue 2, September 2022 - February 2023 Page No: 35-39 Novelty Journals Website: www.noveltyjournals.com Published Date: 06-February-2023 DOI: https://doi.org/10.5281/zenodo.7612848 Paper Download Link (Source) https://www.noveltyjournals.com/upload/paper/The%20Relative%20Sensitivity%20of%20Rotor%20Impedance-06022023-1.pdf, International Journal of Novel Research in Engineering and Science, ISSN 2394-7349, Novelty Journals, Website: www.noveltyjournals.com

The modeling of austenite grain growth of 25Cr2Ni4MoV steel for super-large nuclear-power rotors was investigated during the common heating process including the continuous heating and isothermal heating process. Based on the isothermal grain growth model considering the steady-state grain size and the rule of additivity, a new grain growth model during the continuous heating process was established. The comparison between experimental and predicted results indicates the model has good predictability. To describe the anisotropic and isotropic grain growth during the different isothermal heating stages of the super-large nuclear-power rotor, a cellular automaton model considering anisotropic grain boundary energy for grain growth of 25Cr2Ni4MoV steel was developed. It is found that the anisotropic grain boundary energy mainly exists in the early isothermal heating stage at lower temperatures, and the normal grain growth occurs under anisotropic grain boundary energy conditions. When the temperature is not less than 1273 K and the cellular automaton step is not less than 15, the normal grain growth containing only isotropic grain boundary energy occurs. The analysis of the morphology, energy variance, topology and growth kinetics further indicates that normal grain growth of 25Cr2Ni4MoV steel can be simulated fairly well by the present CA model.

Platelet rich fibrin (PRF) is an autologous blood concentrate, that supports tissue regeneration. The effect of the centrifuge rotor angle in the fabrication of PRF is still not fully elucidated. The hypothesis of this study is: When applying the same g-force {relative centrifugal force (RCF)} and centrifugation time, PRF components and bioactivity are not modified using either a swing-out or fixed angle rotor. For this purpose, peripheral blood samples (five donors )were used to gain solid matrices (710 xg, 8 minutes) and liquid (44 xg, 8 minutes) PRF matrices using three different centrifuges (one fixed angle as a control; and two different swingout rotor centrifuges). The physical characteristics of the solid PRF were measured to evaluate the clot formation and cellular distribution. Liquid PRF was used to evaluate the cell number, bioactivity and influence on primary human osteoblasts and fibroblasts in vitro. Solid PRF clots were significantly larger in the group of fixed rotor centrifuges compared to either of the two evaluated swing-out rotor centrifuges. No differences were observed when evaluating the cellular distribution within the solid No statistically significant differences were documented in the cell's density in liquid PRF samples (platelets, lymphocytes, neutrophils, eosinophils, and basophils) among the differently gained PRF samples. No statistically significant differences were documented for the released growth factors (VEGF, EGF, TGF-β1) over 7 days. Primary human osteoblasts (pOBs) and primary human fibroblasts (pHFs) viability after treatment with PRF conditioned media showed no statistically significant differences between the evaluated groups. However, the number of adherent cells treated with PRF obtained with the use of the fixed angle rotor was significantly higher when compared to those treated with PRF obtained by using the swing-out rotors. The presented results confirmed that regardless of the centrifuge rotor used, the components and bioactivity of solid and liquid PRF matrices are modified by the applied RCF and centrifugation time. These findings are of great importance for highlighting the essential role of adapting the centrifugation protocols when using different centrifuges and to correctly report the used centrifugation protocols in scientific research to allow for reproducible results.

To obtain an accurate rotor position is an important part of sensorless control of permanent magnetic synchronous machine (PMSM) since PMSM is usually operated under speed varying conditions. However, the existing methods cannot provide a satisfactory tracking performance under harmonic polluted condition in wide operating range, which degrade the position detecting accuracy. In this paper, a recurrent neural network (RNN) based phase detection method is used for rotor position estimation of PMSM. To tackle the nonlinear problem in wide operating range of PMSM, RNN is used as a nonlinear dynamic system to establish the mapping relationship of the voltages of stator and rotor position. The proposed method can also provide frequency-adaptive filtering capability to remove the affect of harmonic. To validate the method, a comparison simulations with conventional SRF-PLL method are carried out under speed varying and harmonic disturbances conditions. The results confirm the effectiveness of the proposed method.

This paper develops a nonlinear mid-fidelity aeroservoelastic model for smart rotor wind turbines and studies the turbulent load alleviation of the wind turbines with trailing edge flaps (TEFs) actuated by a novel proportional-derivative model-free adaptive control (PD-MFAC) algorithm. This nonlinear model contains a structural model for the tower and blades represented by geometrically non-linear composite beams and an aerodynamic model for the rotor using a vortex panel method coupled with a stall delay process. The capability of the new aerodynamic model to deal with flow separations and analyze the detailed flow field enables it to simulate the dynamic response of the wind turbine blade sections with TEFs with arbitrary size and deflection angles. It is shown that the TEF alters the aerodynamic coefficients in a complex manner which could be explained by the evolution of the detailed vortical field. Furthermore, three independent PD-MFAC TEF controllers are designed to alleviate the turbulent load acting on the wind turbines. The effectiveness of the controller in terms of turbulent load alleviation is evaluated by the root mean square value of the blade root-bending moment (RBM). A traditional Gain-scheduled PI (GS-PI) controller is also designed as a comparison to the PD-MFAC controller. Simulation results show that to reduce the RBM and blade tip deflection (BTD) caused by external disturbances, the PD-MFAC flap controller shows more effective performance than the GS-PI flap controllers.\ud \ud