Effect Of Winding Research Articles

Non-Hermitian photonic band winding and skin effects: a tutorial

Non-Hermitian photonic band winding and skin effects: a tutorial

Enhanced electromagnetic wave absorption of bacterial cellulose/ reduced graphene oxide aerogel by eco-friendly in-situ construction

Electromagnetic wave absorption materials (EWAMs) have become an effective means to address electromagnetic (EM) radiation and enhance stealth technology, among which aerogels are valued for their lightweight nature and excellent designability. This study utilized environmentally friendly preparation and in-situ reduction techniques to fabricate bacterial cellulose (BC) / reduced graphene oxide (RGO) aerogels, achieving tailored EM wave loss capabilities by controlling the reduction time of ascorbic acid. Benefitting from the effects of freeze-casting, BC winding, hydrogen bond, and RGO layers coupling, the aerogel maintains their original structure after reduction and exhibits satisfactory EM wave absorption. The minimum reflection loss (RLmin) is −38.52 dB, with an effective absorption bandwidth (EAB) of 6.68 GHz and a maximum radar cross section (RCS) reduction of 44.69 dBsm. Additionally, the aerogel’s lightweight (a low density of 9.03 mg/cm3) and outstanding thermal insulation properties enable it to adapt to complex conditions. Thus, the study provides a novel approach for the construction of industrialized and sustainable RGO-based EWAMs.

Study on Winding Design of Dual Three-Phase Electrical Machines for Circulating Current Harmonics and Vibration Suppression

The dual three-phase electrical machines (DTP-EMs) have significant advantages and application potential in large-power and high reliability electromagnetic drive system. Nevertheless, one of the main operating challenges of DTP-EMs is the significant high-frequency circulating current harmonics when supplied with voltage-source inverters (VSIs), which will bring unexpected vibration and loss. This paper provides a thorough study on the mutual magnetic coupling effect and design criterion of dual three-phase winding. First, the mathematical model of DTP-EMs is established. Then, the internal mechanism of mutual magnetic coupling and the relationship among the mutual leakage inductance in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$x$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$y$</tex-math></inline-formula> subspace, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\alpha$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\beta$</tex-math></inline-formula> subspace and stator leakage inductance is revealed. Furthermore, the winding design criterion for DTP-EMs considering high-frequency circulating current harmonics and vibration suppression is proposed. It is drawn that full pitch is required for DTP-EMs to minimize the high-frequency current harmonics and vibration. Finally, two prototypes of the DTP-EM are built and tested to validate the theoretical analysis. This paper provides an effective winding design guide of DTP-EMs for the high-frequency current harmonics suppression and can also be expand to other multi-phase machines.

Effect of stator winding chording on the performance of five phase synchronous reluctance motor

The effect of winding chording on five-phase synchronous reluctance motor (SRM) modelled in phase variables is presented. The stator winding configuration is shifted a pole pitch from a full-pitch configuration to a 54 degrees over-full-pitched configuration incorporating the effect of 3rd harmonic of the air-gap magneto-motive force in the inductance equations. The models are monitored on starting, synchronism, loading, faults and loss of synchronism. These are considered simultaneously with vector potential, rotor speed, air-gap flux linkage and winding current. The phase variable (analytical) models have been simulated by using MATLAB/Simulink software while ANSYS Maxwell software has been used to simulate the finite element model (FEM) of the motor for corresponding chording ranges for comparison on direct online starting (DOL). Under all conditions considered in the work, the detailed results are presented and very close similarity is observed between the analytical and the nearly ideal FEM model for all chording ranges and the similarity is enhanced with increase in chording angle.

Thermal characterization of an interior permanent magnet electric motor

An engineering approach for thermal characterization of an interior permanent magnet electric motor (EM) with a specific aim to identify the interdependency between its mean coil temperature and the maximum component temperatures at the conditions with constant and variable loads/speeds is proposed. For specifying the convective thermal boundary condition between stator and rotor that spins at variable speeds/directions, an experimental study aimed at devising the empirical heat transfer correlation for the Taylor-Couette airflow with varying rotating speed/direction is performed. It is firstly revealed that the responsive air-gap heat convection to angular acceleration follows the characteristic of a single-degree-of-freedom (SDOF) dynamic system. Along with the heat transfer correlation for the unsteady Taylor-Couette airflow, the nonhomogeneous thermal conductivity model that considers the orthogonality effect of the bent coiled winding at its two axial ends is integrated with an iteration scheme for calculating the air bulk temperature in an entrapped air chamber. The favorable experimental validation with the maximum discrepancies between predicted and measured component temperatures less than 7 % in steady and unsteady running conditions affirms the accuracy of the proposed simulation model. At a rotating speed of 4800 rev/min and power output of 1688 W, the maximum-to-mean temperature differences of stator winding, magnetic stripe, and steel sheet of stator reach respectively 6.75 °C, 3.21 °C, and 6.94 °C. Particularly, all the maximum component temperatures are well correlative with the mean temperature of the stator winding at the various steady/unsteady operating conditions. This finding extends the application of lumped thermal network analysis that predicts the averaged components’ temperatures; and enables the on-line monitoring for the maximum component temperatures using a mean stator-winding temperature as the controlling factor.

Experiences with distributed acoustic sensing using both straight and helically wound fibers in surface-deployed cables — A case history in Groningen, The Netherlands

Distributed acoustic sensing has been limited in its use for surface-seismic reflection measurements due to the fiber’s decreased broadside sensitivity when the fiber is deployed horizontally. Deploying the fiber in a helically wound fashion has the promise of being more sensitive to broadside waves (e.g., P-wave reflections) and less sensitive to surface waves than a straight fiber (SF). We examine such claims and compare the responses of SFs and helically wound fibers (HWFs) with different wrapping angles, using standard and engineered fibers. These fibers have been buried in a 2 m deep trench in a farmland in the province of Groningen in The Netherlands, where we performed an active-source survey. We observe in our field data that using HWF has a destructive effect on the surface-wave amplitudes. Our data confirms the effect of the wrapping angle on the polarity of the surface-wave arrival and the dampening effect of the helical winding, behaving in quite a predictable fashion. Apart from the effect of the wrapping angle, the different design choices, e.g., cable filling and material type, do not show a significant effect on the amplitude of the signals. As for P-wave reflections, we observe that engineered SF and HWF provide reflection images comparable with those obtained from simultaneously deployed geophones at the surface despite the SF’s decreased broadside sensitivity. A polarity reversal and an amplitude difference between the SF and HWFs are observed. Finally, we demonstrate that the combined use of SF and HWF proved to be useful because SF showed better sensitivity in the shallower part and HWF in the deeper part.

High proportion and large value harmonic current influence on the magnetic field, loss and temperature distribution for ultrahigh voltage converter transformer

AbstractThe temperature distribution of ultrahigh voltage (UHV) converter transformer is the key to its service life, allowable load and safe operation. The influence of a high‐proportion and large‐value harmonic current on the magnetic field, loss and temperature distribution of a UHV converter transformer is studied. A new calculation method is proposed to determine the winding temperature under the combined actions of multiple key factors. First, the skin effect of UHV converter transformer winding under high proportion and high current harmonics is analysed extensively. It is found that the increase of harmonic current frequency leads to exponential increase of winding loss and temperature by changing skin depth. Second, based on the superposition principle, a calculation method for winding loss considering harmonic current and different load rates is developed. The temperature distribution under different harmonic current frequencies and contents is obtained. The winding losses and temperature under different harmonic currents are quantified. Finally, a new calculation method is proposed for the converter transformer winding temperature, considering the combined actions of factors such as load rate, cooling oil inlet rate and temperature, harmonic current frequency and content. Experimental verification showed an error of only 0.58 K in the actual transformer hotspot temperature, confirming the effectiveness of this method. This method is of great significance for temperature control and safe operation of UHV converter transformers.

Design and experiments of an automatic pipe winding machine

To solve the time-consuming and laborious problem of manual winding and unwinding water pipes by field workers during irrigation or pesticide spraying in agricultural production, an automatic pipe winding machine for winding and unwinding water pipes was designed. The guiding mechanism, pipe winding mechanism, and pipe arrangement mechanism of the pipe winding machine are designed, and the automatic deviation correction control method of pipe arrangement based on PID and the constant tension control method of pipe winding and unwinding is put forward, and the control system of the automatic pipe winding machine is developed. By making a prototype of an automatic pipe winding machine, the effects of pipe winding and unwinding and the constant tension control of the automatic winding machine are tested and analyzed. The test results show that under the condition of 4.0 km/h speed, the maximum angle error of the automatic pipe winding machine is 3.32°, the average absolute error is 0.95°, and the water pipes are arranged neatly and tightly. The maximum relative error of the water pipe tension is 9.3%, and the maximum relative error under the 0~4.0 km/h velocity step variable condition is 16.3%. The speed of the pipe winding and unwinding can adapt to the change of the vehicle’s speed automatically, and the tension of the pipe is within a reasonable range. The performance of the pipe arrangement and pipe coiling of the automatic pipe winding machine can meet the operating requirements.

Experimental Modal Analysis of Stators Analyzing the Effects of Lamination and Winding

Abstract This paper addresses the experimental analysis of different stator configurations of an electric motor typically used within the automotive sector. The ongoing electrification of the automotive sector, combined with a desire to increase virtual prototyping, means that engineers are increasingly facing new challenges. Against this background, the numerical models of electric motors, particularly stators, are simplified and homogenized. However, this procedure must be supplemented by experimental data to ensure the high quality and reliability of the simulations. Unfortunately, broad experimental investigations are time-consuming and expensive, underlined by the lack of corresponding literature. For this reason, four different stator configurations were investigated as part of the experimental modal analysis to highlight the influence of the stator lamination as well as the winding. The results provide the scientific community with a broad outline of how specific influences change modal parameters of each stator configuration. In particular, the results show that lamination significantly reduces axial stiffness. Highlights of the findings relate to the mode-dependent stiffness, mass, and damping influences due to the winding, with the influence of the stiffness deviating significantly from expectation. It was also found that the selected winding technology dominates the structural dynamic system characteristics. Therefore, it is advisable to include the manufacturing technology intended to be used for the lamination and the winding in the early simulative design phase to improve the model prediction quality.

Circulating and Eddy Current Losses in Coreless Axial Flux PM Machine Stators With PCB Windings

Printed circuit board (PCB) stators in coreless axial flux permanent magnet (AFPM) machines have been proposed, designed, and studied for use in multiple industries due to their design flexibility and reduction of manufacturing costs, volume, and weight compared to conventional stators. This paper investigates mechanisms and methods of approximating open circuit losses in PCB stators within example wave and spiral winding topologies for a dual rotor, single stator configuration using 3D FEA, analytical hybrid techniques and experiments. The effect of rotor magnet shape, end winding, and active conductor geometry on eddy currents is studied, and some mitigation techniques are proposed. Through stator equivalent circuit analysis, circulating current losses caused by mechanical abnormalities and magnetic circuit asymmetry are assessed. Possible strategies and schemes to minimize circulating current losses are also described. The trade-off between stator loss components and some practical design considerations are outlined in detail. The open circuit power losses of a prototype coreless AFPM motor were experimentally tested using multiple example PCB stators and emulated rotor asymmetries, with the findings being comparable to the FEA and hybrid analytical methods results.

Integrated Control Strategy for Distortion Current Elimination of Fault-Tolerant Open-End Winding Permanent Magnet Synchronous Machine With Topology Reconfiguration

This article proposes a reconfigured topology of a five-leg inverter for the open-end winding permanent magnet synchronous machine (OW-PMSM) driving system after the device fault condition. Due to the asymmetric structure and common dc bus of the reconfigured fault-tolerant five-leg inverter, the zero-sequence current generated by the dead-time effect and inherent third harmonic voltage of the open-end winding will deteriorate the output torque and the efficiency of the driving system. Thus, the asymmetric property and dead-time effect of the five-leg inverter on the distortion currents of OW-PMSM are analyzed, and an integrated control method with the closed-loop of zero-sequence current and the compensation of dead-time effect and third harmonic voltage are employed to suppress the distortion current for the low-current total harmonic distortion (THD) of the OW-PMSM. The effectiveness and validity of the high-performance OW-PMSM driving system based on the five-leg inverter were verified by the simulation and experimental results.

Impulse Response-Based Induction Machine Model for Starting Simulation Considering Deep-Bar Effect

This paper proposes a novel model for the starting simulation of induction machines (IMs) where its dynamics are computed directly from the impulse response produced by finite element analysis (FEA). This model realizes an accurate starting simulation owing to considering the skin effect of the cage rotor winding, which cannot be entirely represented by the conventional equivalent circuit model even if several auxiliary branches are added on its rotor side to reduce the modeling error in the high-frequency region. Furthermore, the dynamics can be computed by simply executing the convolution integral for the impulse response and input voltage. In other words, the model requires no fitting or approximation to determine the equivalent circuit parameters, which has been studied extensively in many kinds of literature. For the starting characteristics as an example, the accuracy of simulations using the model was investigated thorough comparing its result with that of measurement and FEA. These researches demonstrated that the proposed model provided a remarkable improvement for the starting simulation.

A dynamic relative displacement evaluation method for extra‐high voltage transformer withstanding short‐circuit impact

AbstractThe extra‐high voltage (EHV) transformer winding disks are subjected to dynamic electromagnetic forces caused by short‐circuit currents. These periodically decaying impact forces may endanger the safety of the transformer. The winding constraint conditions around the circumference are different due to the influence of axial pressure structures and magnetic boundaries. Moreover, this difference becomes more evident as the voltage and capacity increase. To investigate the spatial differences and time effects of EHV transformer short‐circuit faults, this paper proposes a reliability evaluation method based on dynamic relative displacement (DRDEM) for the first time. Firstly, the suitable and efficient analysis method is summarized by comparing the deviation among different calculated impedances and the measured value. Then, the space‐time effect of windings is obtained by the static magnetic field and dynamic structural field based on equivalent compression supports. Furthermore, a 50 MVA/110 kV transformer is designed for the destructive short‐circuit test to simulate the short‐circuit ability feature of the EHV transformer. The disassembly phenomena after all the tests indicate that the DRDEM is more adaptable in characterizing the winding ability to withstand short circuit when investigating the spatial differences and time effects.

Design and Construction of Water Heater with Induction Method with Arduino Uno Monitoring

Induction heating is a process in which the heater and the object to be heated are not in physical contact. Therefore, several previous studies did not provide information about the effect of winding and coil diameter on the performance of induction heaters. The sensor used is the Ds18b20 sensor which detects the temperature of hot water and cold water. To increase the effectiveness of the use of heat energy through an induction heater directly, the research tool is an induction water heater. Induction heating is the generation of heat in a metal exposed to an induced magnetic field. In this process, a validated graphic temperature controller is invaluable through the monitoring process using software that can detect the hot temperature of the Blynk and 16X2 LCD. The hot water temperature generated by the induction heater allows the system to operate optimally. As a result, the capillary tube reaches a hot temperature and a constant water temperature of 38 ° C in 173 seconds. The microcontroller and flash connection detection test is working fine. This system makes it easy to carry out the temperature monitoring process via a smartphone.

Experimental study on the influence of high frequency PWM harmonics on the losses of induction motor

For the purpose of studying the influence of high frequency PWM harmonics on the losses of induction motor, this paper first introduces the latest international standard IEC/TS 60034-2-3 for the separation of the losses and the measurement of the efficiency of induction motor under PWM power supply. Then, considering that the skin effect of windings in induction motors under the condition of PWM power supply more apparent, this paper uses the stator AC resistance to replace the stator DC resistance in the IEC/TS 60034-2-3 standard to obtain more accurate separation results. On this basis, an improved method of loss separation for converter-fed induction motor is proposed by using the accurate time-step finite element method to calculate the rotor copper loss under no-load condition which cannot be considered in IEC/TS 60034-2-3 standard. Finally, this method is used to measure and separate the losses of a 5.5 kW converter-fed motor under different operating conditions. The results show that the loss of induction motor which is driven by PWM converter is obviously greater than that of sinusoidal drive, especially under light load or no load condition. The whole no-load losses of the motor driven by PWM converter increases by more than 20.0% compared with that of the sinusoidal driving condition.

Study on the Effect of Suspension Windings on the Electromagnetic Vibration and Noise of Ultra‐high‐Speed Bearingless Permanent Magnet Synchronous Motor for Air Compressor

The electromagnetic vibration and noise level of ultra‐high‐speed bearingless permanent magnet synchronous motor (UBPMSM) for air compressors used in the fuel‐cell vehicle (FCV) is an important evaluation. A 10 kW, 100 k r/min UBPMSM is adopted as the object of study in this research. The expression of radial electromagnetic force of UBPMSM is derived through theoretical analysis, and the order and frequency characteristics of radial electromagnetic force harmonics are summarized. Through the two‐dimensional (2D) Fourier decomposition of radial electromagnetic force by finite element analysis (FEA), the main sources of radial electromagnetic force causing the electromagnetic vibration and noise are studied. The correctness of the mathematical model is verified by FEA. In addition, the three‐dimensional (3D) finite element model of the motor is established to calculate the radial modal, natural frequency, and electromagnetic vibration and noise of UBPMSM. The research shows that the spatial order of radial electromagnetic force of UBPMSM is kN and kN ± 1 (N = GCD [2p, Z], k = 1, 2, 3, …), and the noise change of UBPMSM caused by the addition of suspension windings could be ignored compared with ordinary motor. It provides reference values for the design and optimization of UBPMSM. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Flexural Strengthening of Prestressed Girders with Partially Damaged Strands Using Enhancement of Carbon Fiber Laminates by End Sheet Anchorages

This paper examines the impact of flexural strengthening on the percentage of damaged strands in internally unbonded tendons in partially prestressed concrete beams (0, 14.28%, and 28.57%) and the recovering conditions using CFRP composite longitudinal laminates at the soffit, and end anchorage U-wrap sheets to restore the original flexural capacity and mitigate the delamination of the soffit of longitudinal Carbon Fiber Reinforced Polymer (CFRP) laminates. The composition of the laminates and anchors affected the stress of the CFRP, the failure mode, and thus the behavior of the beam. The experimental results revealed that the usage of CFRP laminates has a considerable impact on strand strain, particularly when anchors are employed. The EB-CFRP laminates increased the flexural capacity by approximately 13%, which corresponds to strand damage of 14.28%, while flexural capacity increased by 9.3%, strand damage increased by 28.57% for members strengthened with laminates only, and around 21.58% and 16.85% for members reinforced with laminates and end anchorings. Quasi-experimental equations have been proposed to estimate the actual stress of untethered tendons considering the effect of CFRP laminates and final fixation winding.

Numerical Study on Thermal Stability of No-Insulation Coils Using a Three-Dimensional Finite-Element Model

No-insulation (NI) coils possessing maximized volume current and quench recovery ability have become one of the most promising technologies for high-field high-temperature superconducting windings. In this article, we constructed a complete 3-D finite element model incorporated with the circuit and heat modules that allows a detailed simulation on the transportation behaviors of the NI coils. Critical problems including the circulating and radial electro-magnetic transportation behaviors during the excitation process with different ramping rates; the thermal propagation in the overcurrent circumstance and related quench protection; and the effect of parallel winding of stainless steel tapes have been investigated using the newly proposed model. A detailed comparison of NI and metal-insulated coils on thermal stability and quench recovery ability with the presence of hot spots has been implemented. Such a 3-D model enables a close look at the electrical and magnetic field distribution, and predicts more accurate coil-parameters for the circuit model where detailed material properties can as well be included.

Common and differential mode of dc-bias in three-phase power transformers

Dc magnetization due to the geomagnetically induced currents (GICs) and HVDC (High Voltage Direct Current) systems may cause core saturation and result in serious destruction in the transformer performance as well as the power system stability. Based on susceptibility, transformers are classified into different groups. For instance, a three-phase, three-limb transformer is considered less vulnerable to effects of GIC compared to a single-phase or a three-phase, five-limb transformer. However, our study shows that such classifications do not apply to the dc magnetization caused by converter modulation. In this article, we introduce the concept of common mode and differential mode to distinguish dc-bias caused by different mechanisms. Main focus is given on differential mode dc current since it has rarely been reported in any literature. The differential mode dc current was demonstrated by system simulations of classic three-level voltage source converters as well as modular multilevel converter. Detailed experimental investigations were made on a three-phase, three-limb transformer, where the loss impact as well as reactive power consumption were studied. The test shows a significant difference in stray loss between the two modes in three-phase power transformers. Finally, we discuss the effect of delta winding on dc-bias of different modes.

Experimental study on dynamic and static structure establishment and recovery rate of fresh cement paste by composite thickening agents

The rheological and thixotropic properties, as well as the establishment of dynamic and static structures effectively reflect the workability of the cement paste. In order to investigate the effects of organic and inorganic composite thickening agents on fresh cement paste, the rheological curves, structural recovery rate, storage modulus G′ and loss modulus G″ of cement pastes mixed with limestone powder (LP), re-dispersible polymer powder (RPP) and hydroxypropyl methyl cellulose ether (HPMC) were tested by Anton Paar MCR 102 rotary rheometer. The results showed that LP and RPP reduced the yield stress and enhanced workability, and LP also improved the establishment of static structures. The incorporation of HPMC facilitated the recovery rate of static structure, and obviously improved the deformation resistance of the cement paste by reducing the difference between the G′ and the G″. However, a single thickening agent was hard to balance the rheological parameters of the pastes. While the combination of LP, RPP and HPMC could improve the rate of structure establishment and recovery, and increase the deformation resistance as well as the stability of the paste. The dense filling effect of LP, the film-forming and bridging effect of RPP, and the winding and water retention effects of HPMC together made up the synergistic effect to further improve the stability of the pastes.