共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
本文通过将“非对称磁路”的设计理念与混合永磁体拓扑结构相融合,提出一种具有“钕铁硼+铁氧体”协同励磁特点的非对称磁路混合永磁电机。通过充分考虑混合永磁体的结构特点,深入分析了磁路的非对称设计机理。为了充分地挖掘该电机的转矩能力,针对性地从钕铁硼转矩分量和铁氧体转矩分量的角度来分析电机的转矩特性。并且,采用冻结磁导率法,实现对钕铁硼转矩分量和铁氧体转矩分量的有效提取与分析。经过参数的优化设计,有效实现了不同转矩分量电流角之间的逼近效应,从而提升了永磁磁场利用率,实现了转矩性能的提升。 相似文献
3.
为研究微波铁氧体器件,需要获知磁化后铁氧体的电磁性能参数。以具有高磁晶各向异性场的六角晶型铁氧体为材料,在22-40GHz的频率范围内对磁化后材料的共极化和交叉极化透射系数进行了测试,然后采用数值仿真透射系数与实验测试结果拟合的方法,得到了磁化六角晶型铁氧体的各向异性场H0为1095kA/m,共振线宽AH为7.5kA/m,饱和磁化强度Ms为160kA/m和在Ka频段时的介电常数ε约为22.1。结果表明六角晶系铁氧体具有高磁晶各向异性场,借助这些已获知的电磁参数,就可以使用此种材料进行微波铁氧体器件的研究与设计。 相似文献
4.
5.
6.
类比有限元法求解铁氧体电感器磁场特征参数 总被引:1,自引:0,他引:1
密绕线匝的铁氧体电感器磁场强度H可认为仅有环向分量,若选择H为自由度,则成轴对称场分布;加载环向电流的电感器选择矢量磁位A为自由度时也呈轴对称分布,该文推导了这两类磁场在各自自由度下满足的微分方程。当两种场具有相同的材料特性、形状及相似的边界条件时,即可通过后者类比求解前者的场分布,由此可以选择矢量磁位A为自由度条件下以轴对称的方式求解铁氧体密绕电感器的磁场分布及对应的磁场参数。以两种结构的铁氧体电感器为例,在计及寄生电容的条件下,建立电感器的R-L-C集中参数模型,由此得到仅含有电阻和电感可测量的串联模型。在10 MHz范围内,等效电阻、等效电感、等效相位角计算与实验取得了一致结果,验证了计算方法的正确性和结果的准确性,为该类电感器在电力电子及其相关领域的设计提供了一条理论分析的途径。 相似文献
7.
利用X射线衍射分析方法,对湿压磁场成型的永磁铁氧体生坯晶体取向度进行了研究。结果表明,采用平行磁场压制成型方法,磁场分布不均匀对晶体取向度具有不利影响,快速压制成型可以有效提高生坯中晶体取向度,文中探讨了这一实验现象的产生原因。 相似文献
8.
Using approximations applicable to near field coupled implants simplified expressions for the complex mutual inductance of coaxial aligned coils with and without a cylindrical ferrite rod are derived. Experimental results for ferrite rods of various sizes and permeabilities are presented to verify the accuracy of this expression. An equivalent circuit model for the inductive link between an implant and power coil is then presented and used to investigate how ferrite size, permeability and loss affect the power available to the implant device. Enhancements in coupling provided by high frequency, low permeability nickel zinc rods are compared with low frequency high permeability manganese zinc rods. 相似文献
9.
铁氧体环形电感器寄生电容的提取 总被引:3,自引:0,他引:3
铁氧体电感器在较高频率时可等效为"电阻、电感"的串联支路与一寄生电容的并联,该电容的存在对电感器的高频性能有重要影响.建立铁氧体环形电感器2D平行平面场和3D静电场有限元模型,分别计算任意两线匝之间的杂散电容,由此得到其等效电容网络.若在电感器输入和输出线匝间加一单位电流,基于节点电压方程,则可求解得到电感器的容性集中参数——寄生电容.在假定该寄生电容与频率无关时,利用测试电感器的谐振频率,可得到该寄生电容.计算与实验对比显示,电感器的边缘效应在静电场的模型建立中占据非常重要的地位,即包括线匝杂散电容计算在内的静电场分析必须以3D模型进行.若仅考虑相邻3匝间的杂散电容,则电感器等效寄生电容值可达考虑所有线匝间杂散电容时寄生电容的95%以上,寄生电容与铁氧体磁心和导线绝缘材料的介电常数呈线性关系,且绝缘材料的介电常数对寄生电容的影响更大. 相似文献
10.
11.
12.
A. S. Tatarenko V. Gheevarughese G. Srinivasan O. V. Antonenkov M. I. Bichurin 《Journal of Electroceramics》2010,24(1):5-9
Magnetoelectric (ME) effects at ferromagnetic resonance (FMR) in ferrite—piezoelectric layered structures have been investigated
in lithium zinc ferrite (LZFO)-lead zirconate titanate (PZT) and yttrium iron garnet (YIG)-PZT. When an electric field E is applied to PZT, the piezoelectric deformation is transmitted to the ferrite and results in a shift in FMR. Data on the
field shift caused by E are presented and compared with theory. Although the strength of ME coupling is weaker in YIG-PZT than in LZFO-PZT, the E-assisted field shift in YIG-PZT is much higher than the resonance line width and is potentially useful for filter applications.
An electric field tunable YIG-PZT microwave band-pass filter based on ME effects at FMR is designed and characterized. The
device can be tuned over a wide frequency band with a bias magnetic field and over a narrow band with a voltage applied across
PZT. Data on tuning range, insertion loss, and device characteristics are presented. 相似文献
13.
针对现有磁性材料湿压成型压机定向充退磁控制系统存在的问题,将用磁簧继电器采集到的充磁临界磁场强度作为控制信号,设计了压机弱磁场强度自动停机系统,有效避免了因磁场系统故障产生的不合格品的出现. 相似文献
14.
15.
16.
The transient electromagnetic fields due to electrostatic discharge (ESD) between charged metals have wide‐band frequency spectra up to the microwave region, which create a serious malfunction for high‐tech information devices. For the above ESD fields, we previously analyzed them, using the finite‐difference time‐domain (FDTD) method, and showed that the metals enhance the field level according to the metal dimension. From the standpoint of reducing such ESD fields, the electromagnetic fields caused by the spark between the metals with ferrite core attachments were investigated. The FDTD method was also used to compute the ESD fields. An FDTD algorithm for the magnetic field inside the ferrite core was newly derived. The results show that the cores attached near the spark gap considerably reduce the magnetic field level, which is also confirmed experimentally. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 34–41, 2002 相似文献
17.
18.
A prototype transformer has been designed and built which is novel in its combination of high voltage (50 kV), high frequency (20 kHz) and high power (25 kVA) specifications. The design technique utilized a spreadsheet approach which facilitated an iterative design procedure. The transformer used a ferrite core, nylon insulated secondary bobbins and pressurized sulfur hexafluoride encapsulation. It was designed as part of a high-voltage switched-mode power supply for driving electrostatic precipitators. The transformer was field tested at a large coal-fired power station and was found to have an efficiency of better than 98% 相似文献
19.
20.
采用线圈式结构设计了近场通信(NFC)天线,并将NiCuZn铁氧体柔性磁片应用于NFC天线系统。利用HFSS仿真软件,研究了天线介质基板厚度、线圈走线宽度、铜线间距以及柔性磁片等对天线回波损耗、谐振频率以及磁场分布的影响。结果表明,天线的走线宽度、走线间距、介质板厚度等参数会影响天线的输入阻抗从而改变谐振频率,最佳的基板厚度0.8 mm、走线宽度a=0.5 mm、走线间距b=1 mm;金属片会导致NFC天线谐振频率偏移,而NiCuZn铁氧体柔性磁片能有效防止金属对天线磁场的干扰以及谐振频率偏移。 相似文献