Flat Wire Research Articles

Evaluation of AC Copper Loss Reduction Effect of Magnetic‐Coated Flat Wire

Evaluation of <scp>AC</scp> Copper Loss Reduction Effect of Magnetic‐Coated Flat Wire

Multi-physical Field Coupling Analysis of Flat Wire Motor

Multi-physical Field Coupling Analysis of Flat Wire Motor

Analysis and Optimization of Winding Losses of Axial Flux Permanent Magnet Machine With Concentrated Winding Flat Wires

Analysis and Optimization of Winding Losses of Axial Flux Permanent Magnet Machine With Concentrated Winding Flat Wires

Detection Method of Stator Coating Quality of Flat Wire Motor Based on Improved YOLOv8s.

The stator of a flat wire motor is the core component of new energy vehicles. However, detecting quality defects in the coating process in real-time is a challenge. Moreover, the number of defects is large, and the pixels of a single defect are very few, which make it difficult to distinguish the defect features and make accurate detection more difficult. To solve this problem, this article proposes the YOLOv8s-DFJA network. The network is based on YOLOv8s, which uses DSFI-HEAD to replace the original detection head, realizing task alignment. It enhances joint features between the classification task and localization task and improves the ability of network detection. The LEFG module replaces the C2f module in the backbone of the YOLOv8s network that reduces the redundant parameters brought by the traditional BottleNeck structure. It also enhances the feature extraction and gradient flow ability to achieve the lightweight of the network. For this research, we produced our own dataset of stator coating quality regarding flat wire motors. Data augmentation technology (Gaussian noise, adjusting brightness, etc.) enriches the dataset, to a certain extent, which improves the robustness and generalization ability of YOLOv8s-DFJA. The experimental results show that in the performance of YOLOv8s-DFJA compared with YOLOv8s, the mAP@.5 index increased by 6.4%, the precision index increased by 1.1%, the recall index increased by 8.1%, the FPS index increased by 9.8FPS/s, and the parameters decreased by 3 Mb. Therefore, YOLOv8s-DFJA can be better realize the fast and accurate detection of the stator coating quality of flat wire motors.

Analysis and Optimization of the Winding Loss of Flat-Wire Motors

The flat-wire motor has the characteristics of small size, low noise, high slot fill factor and good thermal conductivity in the slot. It can significantly improve the power density of the motor and is widely used in electric vehicles. The skin effect and proximity effect of the flat wire under high-speed conditions lead to high loss. Based on the established finite element model of a two-dimensional flat-wire motor, this paper first studies the high-frequency loss of different winding layers and the conductor sizes of each layer. Secondly, the influence of the magnetic field on AC loss is reduced by optimizing the tooth-tip height and tooth-tip width. Finally, it is verified that the high-frequency loss is reduced by 16% with the optimized layers, conductor sizes and tooth-tip sizes under the drive condition of the CLTC-P (China Light-duty Test Cycle—Passenger).

Design and Analysis of an Interior Permanent Magnet Synchronous Motor for a Traction Drive Using Multiobjective Optimization

With the development of new energy industries, the demand for the driving range and power quality of electric vehicle (EV) drive systems is growing rapidly. The drive motor is faced with the challenge of continuously improving power density and performance. This paper proposes a multiobjective optimization method for an interior permanent magnet synchronous motor for a traction drive (IPMSMTD). Based on the flat wire winding technology, the multiobjective optimization design of the IPMSMTD is carried out to improve the motor power density and high-efficiency range, reduce the torque ripple, and suppress the electromagnetic vibration and noise. The structure and size equation of the IPMSMTD are described. The mathematical model considering iron losses is established, and the optimization objectives are determined. Based on the genetic algorithm, a multiobjective optimization mechanism of the magnetic pole structure is established. The operation performance of the motor is analyzed by the finite element simulation and efficiency map. In order to ensure the comprehensive operation index of the IPMSMTD, the vibration noise and modal analysis are carried out, which verifies the rationality of the designed motor and the optimization method.

Multilayer laminated Cu coil/CaO–Li2O–B2O3–SiO2 glass-ceramic preparation via a novel insulation packaging strategy for flat wire motor applications

A new insulation packaging strategy for the stator windings of flat wire motors based on LTCC technology was studied for the first time. The study aimed to replace traditional plastic packaging methods and avoid aging issues by fabricating a novel multilayer laminated Cu coil/CaO–Li2O–B2O3–SiO2 glass-ceramic structure. The analysis of the interface microstructure of the laminated structure revealed that the CaO–Li2O–B2O3–SiO2 glass-ceramic matrix consisted of a crystalline phase of CaSiO3 and an amorphous phase of SiO2. The interface between the Cu coil and CaO–Li2O–B2O3–SiO2 glass-ceramic exhibited good bonding with no formation of secondary phases. Additionally, the strong bonding between the Cu coil and CaO–Li2O–B2O3–SiO2 glass-ceramic was attributed to the diffusion of Cu atoms at the interface. The novel multilayer laminated structure based on LTCC technology proposed in this study can help achieve high-reliability insulation packaging for the stator windings of future high-power density and miniaturized flat wire motors.

Innovative measurement system for saber curvature observation in straightening processes

High-strength wire materials are usually available as strip material and are subjected to a forming process such as punch-bending to produce parts for the electronics industry, for example. During the manufacturing process of the semi-finished product, residual stresses and plastic deformations are introduced into the wire by rolling and drawing processes. Straightening machines are used in the production lines to compensate for these. To increase the sustainability of these production lines, the straightening process is an essential step. Before the continuous manufacturing process starts, the straightening process must be set up and the optimal roller positions must be found. Once the process is set up, the roller position settings are usually not changed. Due to missing measurement systems for the straightening quality, it is not possible to react to fluctuations in the material properties. This leads to deviations in the dimensional accuracy of the components to be produced and thus to an increase in the rejection rate in the manufacturing processes.This paper presents two innovative measuring systems that can detect changes in saber curvature in flat wire during the straightening process. With the help of this information, the quality of the straightening process can be recorded during the running process. This enables the chance to build a control structure for the straightening quality and thus to implement demand-oriented straightening of semi-finished products. On the one hand, this means that the flat wire no longer must be overbent, which means that the strength of the material is not reduced anymore. On the other hand, the sensor information collected can be passed on to downstream processes. This creates the possibility of networking for the individual processes in a production line. This makes an important contribution to the development of intelligent manufacturing processes in line with the guiding principle of Industry 4.0.

Unequal Thickness Flat Wire Winding-Based Eddy Current Loss Reduction for Coreless Axial Flux Permanent Magnet Synchronous Machine Adapted to Extended-Range Electric Vehicles

Unequal Thickness Flat Wire Winding-Based Eddy Current Loss Reduction for Coreless Axial Flux Permanent Magnet Synchronous Machine Adapted to Extended-Range Electric Vehicles

Comparative Evaluation of Durability and Hygiene Between Multistrand Round Dead Soft and 8-Braid Flat Dead Soft Stainless Steel Retainer Wire

Aim and Objectives The present study aims at evaluation and comparison of durability and hygiene between 2 different lingual retainer wires bonded between premolar to premolar, that is, maxillary or mandibular arch in the same patient. Materials and Methods Eighty retainer wires were placed in 40 patients. They were assigned to 2 groups and subjected to 2 different types of retainer wires (multistrand round and 8-braid flat). Results The mean durability of multistrand round retainer wire (235.7 ± 67.28 days) was more than 8-braid flat retainer wire (153.5 ± 43.85 days) irrespective of arches to which they were bonded, which was statistically significant. Scores for plaque index, calculus index, and gingival index were found more with 8-braid flat retainers and in lower arch than multistrand round retainer and in upper arch but these are statistically not significant. Conclusion The mean durability of multistrand round retainer wire was more than 8-braid flat retainer wire. The analysis did not find any statistical significant association for deposition of plaque, calculus, and gingival inflammation between different retainer wires and between arches.

Laser-induced localized and maskless electrodeposition of micro-copper structure on silicon surface: Simulation and experimental study

The simulation and experimental study of laser-induced localized and maskless electrodeposition of micro-copper (Cu) structures on p-type silicon (Si) surface is investigated. Firstly, calculations of the internal temperature field and free electron density distribution within Si under nanosecond laser irradiation were carried out, to demonstrate the selective enhancing effect of laser irradiation on electrical conductivity via the thermal and photoconductive manner. Secondly, experimental tests of the laser-induced electrodeposition of micro-wires, regional coatings and complicated patterns on Si surface without mask were performed successively, to illustrate the effectiveness of the proposed method. The experimental results indicate that laser pulse width and scanning space significantly affect the quality of the deposited layer. Specifically, dense and flat micro wires can be achieved when the laser pulse width is 100 ns, which is associated with a width of about 71.7 μm and thickness of around 10.9 μm. In addition, the laser scanning space should be well optimized to balance the uniformity of the regional coating and the stray deposition near the edge. Finally, the reduction of Cu2+ and deposition of Cu atom at Si surface were discussed, as well as the development of transitional layer, to supply an in-depth analysis of the electrodeposition mechanism.

Novel Straightening-Machine Design with Integrated Force Measurement for Straightening of High-Strength Flat Wire.

In a punch-bending machine, wire products are manufactured for a wide range of industrial sectors, such as the electronics industry. The raw material for this process is flat wire made of high-strength steel. During the manufacturing process of the flat wire, residual stresses and plastic deformations are induced into the wire. These residual stresses and deformations fluctuate over the length of the semi-finished product and have a negative effect on the final product quality. Straightening machines are used to reduce this influence to a minimum. So far, the adjustment of a straightening machine has been performed manually, which is a lengthy and complex task even for an experienced worker. This inevitably leads to the use of inefficient straightening strategies and causes high rejection rates in the entire production process. Due to a lack of sensor information from the straightening operation, application of modern feedback control methods has not been practicable. This paper presents a novel design for a straightening machine with an integrated, precise straightening force measurement. By simultaneously monitoring the position of the straightening rollers, state variables of the straightening operation can be derived. Additionally, a tension control for feeding the flat wire is introduced. This is implemented to mitigate the disturbing effects caused by irregularities in the wire-feeding process. In the results of this article, the high precision of the developed force measurement design and its possible applications are shown.

AC losses calculation of parallel multi‐strand flat wire windings for automotive drive motor

AbstractAutomobile drive motor with flat wire winding has improved the slot fill factor and efficiency. However, under the current environment of drive motors development to high frequency and voltage, the increase in winding AC loss has weakened those advantages. Accurate analysis of AC loss and the design of high‐performance windings have become the key issues and difficulties in the design process of drive motors. Based on the winding AC loss generation mechanism, the authors propose a winding AC loss analysis method, which can effectively separate DC loss, eddy current loss, and circulating current loss. The method is used to analyse winding AC loss of 60 kW flat wire winding permanent magnet synchronous motor (PMSM). In addition, parallel multi‐strand flat wire windings are proposed to reduce the winding AC loss and eliminate the limitation of the magnetic load of the motor on the selection of winding layers. The AC loss of the parallel multi‐strand flat wire windings at different frequencies is calculated, which demonstrates the effectiveness of the proposed winding topology in reducing the winding AC loss. In addition, the correctness of the simulation model was verified through experiments, and the loss calculation method was verified through finite element analysis.

Thermal fluid dynamics of the effect of filler wire on deposition rate and bead formation intending plasma arc-based DED

The influence of filler wire configuration, such as size and geometry, on the deposition rate (DR) and bead formation, has been studied in wire arc-based directed energy deposition (WADED), but the fundamental physics underlying its effect on wire melting and melt pool dynamics remains unclear. In this paper, a series of plasma arc-based DED (plasma-DED) experiments were conducted to investigate the impact of five different filler wire configurations on DR and bead dimensions. The coupling behaviours of wire melting, metal transfer and melt pool dynamics under the five filler wire configurations were also simulated numerically using the authors' recently developed wire-feeding model. The calculated wire melting and bead cross-sections are consistent with the experimental images and measurements. The results demonstrate that the filler wire significantly affects the highest DR by altering wire melting and metal transfer behaviours through changes in arc energy absorption. The filler wire with a rhombus geometry which is closer to a Gaussian-like arc distribution than the flat wire was shown to get higher DR and more stable metal transfer. Furthermore, different filler wire configurations lead to distinct melt pool behaviours, including temperature distribution and flow velocity, due to various metal transfer behaviours and arc shading effects. This study sheds light on the fundamental physics underlying the impact of filler wire on wire melting and bead formation for the first time. The methods and findings can guide improving DR and controlling bead shape in the plasma-DED process.

Joining of Composites with Metals using Graded Metal Fabric Interfaces

A major challenge in the implementation of fibre-reinforced plastics (FRPs) is the provision of stress-appropriate joints with other materials. Establishing a high-strength, graded metal fabric interface using industrially established joining methods is a target-oriented approach in this context. For this purpose, a novel solution based on a textile transition structure in combination with the evaluation of different joining methods is presented in this article. A process chain was developed that depicts both the design and production of textile transition structure as reinforcement material of the FRP component and the further processing to metal FRP composites. Within the textile transition structure, the hybrid fabrics combine glass fibre yarns and metal flat wires, where the latter enable the joining process and transfer loads into the reinforcing glass fibres. The manufacturing implementation of this new joining interface from the textile to the hybrid component is described in detail within the paper. Furthermore, results of mechanical load tests of the graded metal fabric interface are presented. The research results make a significant contribution to the development of innovative graded metal fabric interface with a benign failure behaviour and a great potential especially with regard to the efficient joining of mixed material constructions in large-scale applications.

Design of Induction Motors With Flat Wires and Copper Rotor for E-Vehicles Traction System

This paper deals with the design of a 200kW/ 370Nm, induction machine for electrical vehicles traction system. The design aims to enhance the performance of the current induction machine technology for mass production making it suitable to be a rare earth free solution for electric vehicle applications. To this extent, suitable materials have been analyzed and selected, also by using of mechanical analysis and experimental data. Rotor die-casting, hairpin stator winding and specific cooling systems have been adopted within the proposed solutions. Extensive analytical and numerical methods are used for performance evaluation all over the full speed range of the machine.

AC Loss Analysis and Measurement of a Hybrid Transposed Hairpin Winding for EV Traction Machines

To address the problem of high-frequency AC loss of hairpin winding, a hybrid transposed hairpin winding (HTHW) scheme, which combines flat wire and litz wire, is proposed. The HTHW can effectively reduce the high-frequency AC loss, while maintaining a relatively high slot fill factor. In this paper, the AC loss generation mechanism under high-frequency excitation is firstly analyzed. Then, based on the field-circuit-coupled finite element method, the current density distribution and AC loss of hairpin winding with different transposed topologies are calculated and compared. Finally, an experimental platform enabling direct measurement of hairpin winding loss is built to verify the simulation. The simulation and experimental results show that the AC loss of the proposed HTHW is much lower than that of the traditional hairpin winding, for medium to high running frequency. In our case, the AC and DC resistance ratio of the presented HTHW is 2.12 at the frequency of 1200 Hz, contrasting that of the ratio of traditional hairpin winding, which is 10.2.

Research on Novel Flat Wire Transposed Winding of PMSM for Electric Vehicle

Permanent magnet synchronous motor (PMSM) for electric vehicles is developing higher frequency and speed but triggering a significant increase of eddy current loss. To resolve the eddy current loss issue, a novel flat wire transposed winding composed of double-row multiple parallel strands is proposed. Transposed winding techniques have been proved to be efficient in reducing eddy current loss by preventing the uneven leakage magnetic field induced by high frequency. The proposed transposition further improved this technique in reducing circulating current loss. Taking a 60-kW PMSM as an example, the novel flat wire transposed winding arrangement is carried out. The 3-D field-circuit coupled finite-element models of 360° complete transposed and incomplete transposed winding PMSM are established, and circulating current losses are compared. The analysis results show that incomplete transposed winding has a better performance in reducing the circulating current loss. The transposition method suitable for novel flat wire transposed winding is obtained, and the feasibility of PMSM with novel flat wire transposed winding to reduce winding losses is proven.

Estimating and Mapping Extreme Ice Accretion Hazard and Load Due to Freezing Rain at Canadian Sites

The ice accretion load in Canadian structural design codes is developed based on an operational ice accretion prediction model. In the present study, three models are employed to predict the ice accretion amount on a flat surface and horizontal wire at Canadian sites. The results confirm that the model used by Canadian practice for predicting ice accretion leads to a conservative estimate as compared to the remaining two models. The results also indicate that the use of the Gumbel distribution for the annual maximum ice accretion is adequate for regions prone to ice accretion and that the lognormal distribution may be considered for regions with a moderate or negligible amount of ice accretion. Maps of the ice accretion hazard at five selected Canadian sites are developed. Statistical analysis of an equivalent wind speed that is concurrent with the iced wire is carried out, showing that the concurrent wind speed for the 50-year return period value of the annual maximum ice accretion amount is smaller than the 50-year return period value of the annual maximum wind speed. It is shown that the statistical characteristics of the annual maximum concurrent wind speed on iced wire differ from that of the annual maximum wind speed.

Large-scale metal strip for power storage and energy conversion applications by machining-based deformation processing

Machining-based deformation processing is used to produce metal foil and flat wire (strip) with suitable properties and quality for electrical power and renewable energy applications. In contrast to conventional multistage rolling, the strip is produced in a single-step and with much less process energy. Examples are presented from metal systems of varied workability, and strip product scale in terms of size and production rate. By utilizing the large-strain deformation intrinsic to cutting, bulk strip with ultrafine-grained microstructure, and crystallographic shear-texture favourable for formability, are achieved. Implications for production of commercial strip for electric motor applications and battery electrodes are discussed.