Effect of coil and chamber structure on plasma radial uniformity in radio frequency inductively coupled plasma

Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing.This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP.The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density.Furthermore,optimizing the coil within the ICP reactor,using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity,elevating it from 56%to 96%within the range of the model sizes.Additionally,when the chamber aspect ratio k changes from 2.8 to 4.7,the plasma distribution changes from a center-high to a saddleshaped distribution.Moreover,the plasma uniformity becomes worse.Finally,adjusting process parameters,such as increasing source power and gas pressure,can enhance plasma uniformity.These findings contribute to optimizing the etching process by improving plasma radial uniformity.

Transient multi-physics behavior of an insert high temperature superconducting no-insulation coil in hybrid superconducting magnets with inductive coupling

A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet during the charging and discharging processes.The coupled problem is resolved by means of the finite element method(FEM)for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system.The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet.Moreover,a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process,while a forward azimuthal current and a tensile hoop stress are observed during the discharging process.The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists.Therefore,it brings forth significant Joule heat,causing a temperature rise and a uniform distribution of this heat in the coil turns.Accordingly,a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil.It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil,while a discharging will not.The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.

Effect of power parameter and induction coil on magnetic field in cold crucible during continuous melting and directional solidification

Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment and production.In this study,a 3-D finite element (FE) method based on experimental verification was applied to calculate the magnetic flux density (Bz).The effects of the power parameters and the induction coil on the magnetic field distribution in the cold crucible were investigated.The results show that higher current intensity and lower frequency are beneficial to the increase of Bz at both the segment midpoint and the slit location.The induction coil with racetrack section can induce greater Bz,and a larger gap between the induction coil and the shield ring increases Bz.The mechanism for this effect is also discussed.

Method of measuring rotation speed of high spinning projectile based on plane magnetic induction coil

For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.

Consecutive induction melting of nickel-based superalloy in electrode induction gas atomization

The crucible-free electrode induction melting gas atomization（EIGA） technology is an advanced technology for preparing ultra-clean nickel-based superalloy powders. One of the key issues for fabricating powders with high quality and yield is the consecutive induction melting of a superalloy electrode. The coupling of a superalloy electrode and coil,frequency, output power, and heat conduction are investigated to improve the controllable electrode induction melting process. Numerical simulation results show that when the coil frequency is 400 kHz, the output power is 100 kW, superalloy liquid flow with a diameter of about 5 mm is not consecutive. When the coil frequency is reduced to 40 kHz, the output power is 120 kW, superalloy liquid flow is consecutive, and its diameter is about 7 mm.

A Magnetic Induction Tomography System for Prospective Industrial Processing Applications

Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that the MIT may be useful for low conductive process imaging.This paper presents a cost effective hardware design for MIT in industrial applications,called Bath-MKI industrial MIT system.The system comprises 8 inductor coils and has the possibility of expansion to 16 coils.The excitation signals and the measured voltages are generated and measured using a LabView based system.Two 16 by 1 multiplexers are used to select between the coils.Measurements,excitation and multiplexing are all controlled by a National Instrument(NI) USB based DAQ:USB-6259 and a signal generator.Using the same electronics,the prototype is tested with two different coil arrays;one is a small scale ferrite core coil and one larger scale air cored coil.Experimental image reconstruction results are shown using both small scale and large scale coil arrays.

Mutual Inductance Calculation Between Arbitrarily Positioned Polygonal Coils

Polygonal coil systems are designed for increasing and more kinds of sensors and electromagnetic systems.This paper presents a method for calculating mutual inductance between polygonal coils including irregular polygons.Based on the Biot-Savart law,the method calculates mutual inductance by dividing a polygonal coil into finite wires,and expresses the magnetic induction intensity generated by the excitation coil as a function of the spatial position of each vertex of the coil.The calculation method of the feasible region of the objective function is updated and the calculation process is simplified,so the calculation accuracy is improved.For octagon coils arbitrarily positioned in space,the accuracy of the algorithm is verified by the simulation and experiment.

同轴多层筒式空心线圈自感和互感解析计算方法

在电磁耦合的无线电能传输系统中,准确获取线圈电感参数是设计和优化无线电能传输系统的重要理论依据。现有的无线电能传输系统研究大多针对平面板结构线圈,同轴多层筒式空心线圈相比于平面板线圈具有更高的传输功率和传输效率。因此,该文针对同轴多层筒式空心线圈,提出了一种考虑高频涡流效应的自感和互感解析计算方法。首先,将单匝线圈截面离散等效为数量众多、形状相同的网格带电圆环单元,采用离散等效求和法推导出单匝线圈的自感和线圈间互感的解析式;然后,基于筒式空心线圈的整体结构以及考虑高频涡流效应,推导出基于第一类、第二类完全椭圆积分和开尔文函数的一、二次线圈自感和总互感计算的理论解析式;最后,以两种不同排布方式的筒式空心线圈为例,对比解析计算、有限元计算和实验测量结果,验证了所提解析法的可行性,同时也为筒式空心线圈的设计提供参考依据。

基于自激振荡原理的双线圈磨粒检测技术研究

为满足实际工业应用的需要,基于LC自激振荡,提出双线圈式磨粒检测技术。首先建立了等效电路模型,其次引入磁场均匀度系数的概念并利用COMSOL Multiphysics仿真软件研究了管道域中的磁场分布及金属颗粒通过线圈时的输出响应,最后制作传感器进行试验。结果显示,该传感器管道域的磁场均匀度系数达0.91以上,可通过检测电压、频率的变化获取磨粒信息。研究结果为电感式磨损传感器研发提供一种新思路。

子午工程二期宽频地磁波监测仪研制

地球的磁层中存在各种波现象,其频率从mHz延伸到数千Hz.这些波的研究一直是空间物理学研究的核心问题.针对目前世界上地磁台站的波监测设备均为各自测量相对变化、缺乏统一标定、无法进行从高纬到低纬联合观测、无法进行多台设备观测数据的统一对比研究的现状,本文综合使用磁阻传感器(探测ULF频段:1 mHz~2 Hz)、巨磁感抗传感器(探测ELF频段:0.2 Hz~2 kHz)和线圈传感器(探测VLF频段:0.2 kHz~10 kHz)研制新一代的宽频地磁波监测仪,将这些监测仪放置在120°E子午链附近的黑龙江漠河站(高纬)、北京十三陵站(中纬)、海南乐东站(低纬)等典型区域的地磁台站上,并对各个台站的设备进行统一的时间、振幅和频率标定,结合FY-3E、SMILE等近地空间卫星数据,全面提升对地球磁层的各种波现象的探测能力.研制的宽频地磁波监测仪的性能测试实验表明,其具有对一定频率(1 mHz~10 kHz)的波的探测能力;其幅度探测范围为:±65000 nT(ULF频段)、±1000 nT(ELF频段)、±100 pT(VLF频段);在量程范围内又具有较低的非线性误差:ULF频段≤0.0446%、ELF频段≤0.51%、VLF频段≤1.18%;噪声水平也较低:RMS(方均根)噪声≤0.5554 nT(ULF频段)、NPS(功率谱)噪声≤0.028 nT/√Hz(ELF频段)、NPS(功率谱)噪声≤0.24 pT/√Hz(VLF频段).所有这些特点使得所提出的宽频地磁波监测仪能够满足子午工程二期的波探测需求.

基于互感稳定性提升的电动汽车无线充电研究

针对采用磁耦合谐振式无线电能传输技术的动态电动汽车无线充电过程中,汽车底部的能量接收线圈在直线行驶和转弯过程中发生的互感跌落、互感波动率增大的问题,提出一种源自BP(Bipolar Pad)线圈结构的改良式接收线圈,从而达到平稳接收互感,增强无线传输过程中稳定性的目的。该改良式线圈通过双线圈分别贴合轨道内外径的方式解决了传统BP线圈因解耦而造成的正对耦合有效面积的减少,并利用Ansys/Maxwell软件进行仿真寻优,得到补偿线圈的合理设计位置及相对大小。实验数据表明,无论在汽车转弯还是直线行驶过程中,新型接收线圈均可以在一定程度上抑制互感波动,增强接收互感数值。互感波动率优化峰值为5.1%,互感接收情况较传统BP线圈最大提升28.7%。

电动汽车无线充电系统中弯道互感优化研究

针对采用感应耦合电能传输技术的电动汽车无线充电过程中,汽车内部的能量拾取线圈在转弯过程中互感下降问题,提出使用内嵌入圆形线圈进行补偿,并通过遗传算法、理论推导和仿真验证,得到了补偿线圈最优化匝数和统一规格参数。通过搭建COMSOL Multiphysics平台、MATLAB/Simulink平台结合的仿真平台和实物实验平台,实验数据证实:在转弯时采用内嵌圆形线圈进行补偿,优化补偿后互感波动保持在±0.4%左右,由于互感波动的平稳,使得电动汽车能量拾取系统电压优化补偿后波动为3.6%。

同步感应线圈发射器弹载存储测试技术研究

该文提出多级同步感应线圈发射器弹载存储动态测试技术。首先,基于电磁场理论定量分析了同步感应线圈发射器发射过程中存在的强脉冲和高过载环境;其次,设计具有抗电磁干扰且抗高过载能力的弹载存储测试装置,并分析了装置的屏蔽效能和承载能力;最后,研制带弹载存储测试装置的测试弹,并开展了30级同步感应线圈发射器动态发射试验,得到同步感应线圈发射器动态过程中磁感应强度数据和加速度数据,与仿真数据吻合,且误差可控制在4.7%,同时揭示了发射始末测试弹存在“规律碰撞”效应和“周期章动”现象。

电磁感应加热装置中磁-热-流耦合特性分析

采用磁热流多元物理场耦合仿真的方法,研究感应加热系统中的不同线圈结构、激励条件下壁面欧姆损失、温度特征值、磁场强度等多物理场相关的特征值,由结果可知:线圈结构以及激励条件会对磁场及温度场产生不同程度的影响,壁面的欧姆损失与电流幅值、电流频率、线圈匝数呈正相关,与线圈与管道中心的距离呈负相关;随着电流幅值从100 A升高至180 A,壁面加热功率从167 W提升至3223 W,出口平均温度从20.5℃提升至28.6℃;管壁内的电流密度以及磁通密度会随着线圈内电流频率的增加而更加集中于管壁薄层内;随着线圈频率从0.05 kHz提升至20 kHz,不锈钢表层内的最大电流密度将从1.29×10^(6)A/m^(2)升高至1.25×10^(8)A/m^(2);当电流频率为0.05 kHz时,最大磁通密度为0.5 T;当电流频率为20 kHz时,最大磁通密度为4.8 T。

无线电能传输带凸字环形有界磁屏蔽任意位置圆形线圈互感计算方法

互感是无线电能传输系统中的重要参数之一,精确计算互感可为无线电能传输设计及优化提供理论依据,然而目前带凸字环形有界磁屏蔽任意位置圆形线圈互感计算问题还未解决。该文提出空间边界矢量解析法对互感进行精确求解。此方法通过边界条件求解各区域磁矢势,利用空间矢量坐标变换法,结合诺依曼公式得到任意位置互感计算表达式。通过仿真和实验对所提公式的有效性进行验证,互感计算值和实验值之间误差最大为2.86%。互感计算值、仿真值和实验值吻合良好,验证了所提计算方法的正确性。该文所提模型结构,可为水下供电提供更灵活的布局,且在同等规格下,该模型结构相比传统圆盘形结构节省19.6%的材料,其除高角度偏转外互感可达到圆盘形互感的99%。

双线圈并联ICPT系统的分布式补偿电流均衡方法

针对双线圈并联的高功率感应耦合电能传输(ICPT)系统存在线圈间补偿电流不均衡问题,提出一种分布式补偿电流均衡方法。首先提出了双线圈并联ICPT系统的分布式补偿网络,然后依据等效思想和迭代思想提出补偿电流均衡方法,根据该方法求解得到补偿参数和各线圈补偿电流表达式,再将该方法拓展到n线圈并联结构。在北京超算云计算中心的COMSOL云平台验证了所提出的方法不仅有效均衡了各线圈的补偿电流,而且谐振状态受参数漂移的影响程度并未因补偿网络的复杂程度增加而增加。最后搭建了实验平台,验证了所提方法的有效性。

青贮机铁磁性金属异物智能检测报警系统

[目的/意义]青贮机作业时,田间遗落的铁丝等铁磁性金属异物如果混入其喂入系统,将会对青贮机的关键零部件和牲畜脏器造成严重损伤。为了确保青贮机在田间作业时能准确、高效地检测出金属异物,本研究开发了一套性能优良的金属探测系统。[方法]首先分析了青贮机金属检测原理,然后对平面螺旋线圈与圆柱线圈进行了仿真计算,选择平面螺旋线圈作为研究对象,通过使用非支配排序遗传算法(Nondominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)结合有限元仿真分析的方式,确定了线圈的线径、内径、外径、层数以及频率,并对弯曲线圈与未弯曲线圈以及阵列线圈进行了仿真计算。最后进行了系统集成,搭建了青贮机模拟试验台进行了模拟试验。[结果和讨论]仿真分析结果显示,平面螺旋线圈磁通密度模变化范围明显大于圆柱线圈,且其电感灵敏度、电阻灵敏度和被测物涡流损耗要明显高于圆柱线圈;另一方面,平面线圈弯曲后电感灵敏度、电阻灵敏度大幅度提高,有利于增强探测线圈的响应度。通过模拟台架试验,验证了该金属探测系统在探测距离小于70mm,对直径0.6 mm、长度20 mm铁丝报警率达到100%,且经过计算,系统响应时间为0.105 0 s,小于安全运输时间,系统可以在金属物到达切碎系统前及时停止。[结论]本研究设计出了一套青贮机金属异物探测系统,提出了一套金属探测线圈的优化方法,并开发了相应的金属探测软硬件系统,通过试验验证了金属探测系统的功能,为青贮机安全运行提供了有力技术支撑。

谐振法手持式智能磁化率仪设计

文章基于谐振原理设计了一款手持式智能磁化率仪,推导了谐振原理法测量岩石磁化率计算公式,仿真探究谐振法测量岩石磁化率的影响因素,结合仿真结果与实际探测需要对仪器进行整体设计。基于LDC1614搭建外围电路,设计了4层螺旋线圈等距并联的电感传感器、信号提取程序和上位机操作界面,完成了磁化率仪样机制作。该仪器轻便易携(重量仅0.2 kg)、操作简单,测量结果与国外同类仪器比较误差低于5%,仪器精度可达10-7。仪器适合野外及实验室测量,具有实际工程利用价值。

基于集电线圈复用的电动磁浮列车感应式电能传输技术研究

为实现电动磁浮列车低速运行阶段无接触辅助供电,同时尽可能减轻耦合机构重量,并保障供电系统平稳输出,该文设计了一种利用磁浮系统原有线圈作为耦合机构的感应式电能传输(IPT)系统,通过线圈与电路结构重构,以列车低速运行阶段空置的悬浮线圈与集电线圈作为能量传输通道。由于不需额外安装能量传输线圈,所提出的IPT系统对磁浮列车自重影响小,且耦合机构在移动过程中具有互感恒定的特性,结合LCC-S谐振补偿电路,IPT系统在列车移动过程中与负载变化过程中均能保持稳压输出。为验证所提方案的可行性和有效性,搭建了1 kW的原理样机,在移动供电过程中,IPT系统输出电压波动仅1.51%,输出功率在300~1000 W范围变化时,输出电压波动为4.42%,系统整体效率为83.75%~86.61%。

电动汽车动态无线充电系统弯道互感跌落研究及改进

针对目前电动汽车动态无线充电系统的发射线圈多采用分段导轨结构实现接力式动态无线充电,但系统在导轨切换处存在较大的互感跌落导致系统传输效率降低且在弯道处更加突出这一问题,建立弯道动态无线充电模型,通过理论分析推导原、副线圈互感与偏转角度的关系,提出1种弯道处导轨发射线圈的改进结构并进行仿真分析,搭建基于共振磁耦合的弯道动态无线充电平台并进行实验。仿真与实验结果表明,采用改进型导轨发射线圈结构后无线充电系统互感跌落现象显著减小,在偏移角度最大处系统传输效率提升了8.66%,验证了改进型线圈结构的有效性。