本瞬态模型通过磁芯中的非线性 B-H 曲线描述单相 E 磁芯变压器。图上显示了主/从线圈中的电磁场和电流。
材料属性和本构关系通过介电常数、磁导率、传导率和剩余场定义。材料属性是空间依赖、时间依赖、各向异性和包含损耗。电介质和磁介质均可包括非线性因素（例如 B-H 曲线），或通过隐式方程进行描述。
将电气元件视为一个更大系统的一部分时，AC/DC 模块提供了一个带有 SPICE 电路列表的接口，供您选择用于进一步模拟的电路元件。使用基于电路的模拟可以开发更复杂的系统模型，同时保持与电路中关键器件的完整物理场模型之间的关联，从而可以同时在两个层级上实现设计创新和优化。电子器件的布局可以通过 ECAD 导入模块，使用 AC/DC 模块来进行分析。而且这种布局的仿真并不仅仅局限于电磁场。
- 永磁体：本案例模拟了使用永磁体构成的磁力转子产生的以向外磁通量为主的静磁场。这种磁力转子也称为哈尔巴赫转子。由于操作中不产生接触、无摩擦，永磁体在电动机、发电机和磁力齿轮等旋转设备中的使用日益流行。本模型演示了如何在对称条件下，只需要通过对单个转子进行模拟，计算三维 4 极成对转子的磁场。
- ECAD 导入：利用 AC/DC 模块计算以 ECAD 文件格式导入的平面变压器模型的电容和电感。这种类型的器件用于必须使用超薄高功率设计的电源和直流/直流转换器。通过 ODB++(X) 文件导入整个布局（包括变压器铁氧体磁芯的外形）。ECAD 导入模块用于读取布局并自动创建印制电路板（PCB）和铁氧体磁芯的三维几何模型。
- 医疗技术：X 射线设备中的高压生成器的电磁场仿真。模型由 Comet AG, Switzerland 提供。
- 质谱分析：AC/DC 模块与粒子追踪模块耦合仿真。可视化显示了具有特定电荷质量比的离子在四极质谱仪中的运动轨迹。
与 CAD、MATLAB® 和 Excel® 链接
为了方便您分析机械 CAD 模型的电磁属性，COMSOL 提供了 ECAD 导入模块、CAD 导入模块和高级 CAD 系统的 LiveLink™ 模块。LiveLink 模块可以将参数化 CAD 模型保留在各自的环境中，并从 COMSOL Multiphysics® 内控制几何尺寸，还可以对多个模型参数同时进行参数化扫描。对于重复性模拟作业，LiveLink™ for MATLAB® 允许您使用 MATLAB® 脚本或函数来运行 COMSOL® 模型。COMSOL Desktop® 中用到的所有操作都可以改为通过 MATLAB 命令行的方式来运行。您还可以在 MATLAB 环境中将 COMSOL 命令与现有的 MATLAB 代码混合使用。对于从电子表格中操作的电磁仿真，LiveLink™ for Excel® 提供了一种从 COMSOL Desktop 与包含COMSOL 环境中定义的参数的电子表格数据同步建模的方法。
虽然设备属性可能主要由电磁场决定其特性，但它们也会受其他类型的物理场影响。例如，热效应可以改变材料的电气属性，在发电机的每一步设计过程中，都需要充分了解发电机中的机电挠度和振动。AC/DC 模块全面地集成在 COMSOL 环境中，可以考虑各种各样的影响虚拟模型的物理效应。
AC/DC 模块使您可以使用一系列基本边界条件，例如电势和磁势、电绝缘和磁绝缘、零电荷以及场和电流等。此外还包含了一系列高级边界条件，例如，与 SPICE 电路连接的终端、悬浮电位、对称性和周期性边界条件、表面阻抗、表面电流、分布电阻、电容、阻抗和接触电阻等。要模拟无限大或大尺度模型，可对电场和磁场使用无限元方法。在有限大的模型区域外部添加一个无限元层时，将自动调整物理场方程的尺度。这使得可以使用一个有限大的模型表示无限大的域，并避免模型边界的人工截断效应。
对于非常薄的结构，AC/DC 模块提供了一系列专用公式来进行高效的电磁仿真，此时结构的物理厚度不再需要在几何模型中表示出来，而是改为使用一个薄壳表示。这种薄壳公式可用于直流、静电、静磁和感应仿真，对于电磁兼容 (EMC) 和电磁干扰 (EMI) 中的电磁屏蔽特别重要。
以下步骤描述了该模块简洁的建模流程：定义几何结构、选择材料、选择适合的 AC/DC 模块接口、定义边界条件和初始值、自动创建有限元网格、求解，以及结果可视化。所有这些步骤均从 COMSOL Desktop® 中访问。通过一系列预定义的多物理场耦合接口或用户自定义耦合，使用任何能想象到的方式，可将 AC/DC 模块仿真与每个 COMSOL 模块耦合。一个典型的预定义模式是 AC/DC 模块和粒子追踪模块之间耦合模式，这里电场或磁场会作用于有质量或无质量的带电粒子。优化模块可以与 AC/DC 模块耦合，对电压和电流激励、材料属性、几何尺寸等参数进行优化。
AC/DC 模块包含了二维和三维的静态和动态电磁场分析。AC/DC 模块会在底层方程中生成麦克斯韦方程组，并根据材料属性和边界条件进行求解。软件使用有限元方法，通过数值稳定的棱边元离散，配合最先进的求解器求解这些方程。静态、频域和时域模式分别使用不同的公式进行仿真。结果图形窗口中会呈现一些预设绘图：电场与磁场、电流与电压，或用户自定义物理量与派生值。
Switching Made Easy
Matthias Richwin, Leopold Kostal GmbH, Dortmund, Germany
Modern cars offer a wide range of complex functionality that comes with several design challenges. This story discusses some of the necessary updates to a roof module in a premium car and the charging system of an electric car. The roof module of a particular model houses several components. 90% of the generated heat goes into its printed circuit ...
Current Transformer Design That Combines Finite Element Analysis and Electric Circuit Simulation
Dr. Rolf Disselnkötter ABB AG, Ladenburg, Germany
Transformers have been around for quite a while but their fundamentals are still being investigated by ABB in Ladenburgh, Germany. The ABB Corporate Research Centre is currently developing sophisticated magnetic sensors, using finite element analysis (FEA) to investigate the way in which external electrical sources and loads impact a magnetic ...
MRI Tumor-Tracked Cancer Treatment
Gino Fallone and colleagues Cross Cancer Institute Edmonton, AB, Canada
Radiation therapy targeting in cancer treatment involves many uncertainties, including the movement of targeted sites due to breathing and the like. Magnetic resonance imaging (MRI) can accurately identify the location of a tumor in soft tissue, but unfortunately its magnetic field can interfere with radiation treatment delivered by a linear ...
Multiphysics Simulation Helps Miele to Optimize Induction Stove Designs
Christian Schröder mieletec FH Bielefeld Germany Holger Ernst Miele Germany
The induction stove was designed to meet a consumer need for better precision and speed than traditional stoves. Designers were tasked with improving the energy efficiency of the induction coils-stovepot interaction considering both the thermal and electromagnetics of the system. Miele, a world leader in domestic appliances and commercial ...
Upgrading the Nuts and Bolts of the Electrical Grid for a New Generation
Göran Eriksson ABB AB Corporate Research Power Technologies Västerås, Sweden Lukas Graber, Mikael Steurer, and Tim Chiocchio Center for Advanced Power Systems Florida State ...
Migrating the electrical grid to a “smart grid” is usually discussed in terms of IT issues or embedded systems. Yet, just as important updating the “nuts and bolts” of the smart grid. At ABB AB Corporate Research Power Technologies in Sweden, scientists are working to reduce line current and the resulting resistive loss in cables caused ...
Multiphysics Software, a Versatile, Cost-Effective R&D Tool at Sharp
Chris Brown Sharp Laboratories of Europe, UK
There are several kinds of technology that designers at Sharp Laboratories of Europe work to create. From LED lighting, displays, and microfluidic lab-on-a-chip technology, to complex energy systems used in various devices, Sharp needed a new approach to finding the best designs. COMSOL Multiphysics and its add-on products provided the versatility ...
Dielectric Stress Simulation Advances Design of ABB Smart Grid-Ready Tap Changers
Tommi Paananen, David Geibel, Bill Teising, Mårten Almkvist, Jon Brasher, Josh Elder, Bob Elick and Chris Whitten ABB Alamo Tennessee
Consumers of power rely on fairly stable voltages. Transformers contain tap changers which vary the ratio of secondary to primary turns by switching the point at which either the input or output circuits are connected. Changing this ratio enables stepped voltage regulation of the output. As the world moves toward the modernized smart grid, the tap ...
Simulation of Magnetic Flux Leakage Inspection
Oliver Nemitz Salzgitter Mannesmann Forschung, Duisburg, Germany
Salzgitter Mannesmann Forschung (SZMF) advances testing methods for the Salzgitter Group, a leading company that works with the manufacture of, among other things, pipes. In the manufacturing of heavy steel tubing, it is important maintain quality, which is done through conduct non-destructive testing (NDT) using large magnets to identify flaws ...
Control of Joule Heating Extends Performance and Device Life
Jean-Louis Gelet and Antoine Gerlaud Mersen, France
Large electrical systems carrying high currents could pose a danger if any of their components, such as fuses and bus bars, fail. In order to increase safety and improve manufacturing, it is necessary to understand the failure mechanisms of those components. One of those components, a bus bar, is made up of a single piece of conducting metal that ...
Lightning-Proof Wind Turbines
Soren Find Madsen Global Lightning Protection Services A/S, Lejre, Denmark
Søren Find Madsen, Global Lightning Protection Services A/S, Lejre, Denmark Global Lightning Protection Services A/S (GLPS) is an engineering consultant firm specializing in lightning protection. Their current research involves protecting wind turbines from lightning strikes, which can interfere with the electronic equipment in the housing of ...
How Reclosers Ensure a Steady Supply of Power: It’s all in the Magnet
O. Craciun, and colleagues ABB AG Ladenburgh, Germany
When a tree branch touches overhead cables and causes a momentary short circuit, your lights may flicker. A device called a recloser ensures that power to your home is not cut off for a longer period. ABB AG, a leading manufacturer in power technology, is working towards designing a more reliable recloser. One objective in this design process was ...
Simulation-Based Design of New Implantable Hearing Device
Patrik Kennes Cochlear Technology Centre, Mechelen, Belgium
Cochlear Technology Centre Europe (CTCE) develops new technology for hearing implants. Their current work is with a new type of hearing implant, a Direct Acoustic Cochlear Implant called CodacsTM. This product imposes structural, pressure waves directly to the cochlea, stimulating it this way, as opposed to amplifying sound. Using COMSOL ...
Multiphysics Simulations Help Track Underground Fluid Movements
A. Haas, H. Mahardika, M. Karaoulis, and A. Revil Colorado School of Mines, USA
Combining acoustic and electromagnetic analyses helps scientists to more efficiently measure and survey subterranean regions. Acoustic waves can travel long distances, but have limitations when it comes to providing details about formation properties, and cannot be used to identify the liquids flowing through them. Electromagnetic waves do not ...
Reduced-Weight Reaction Sphere Makes Way for Extra Satellite Payload
Leopoldo Rossini, Emmanuel Onillon, & Olivier Chetelat CSEM SA, Neuchatel, Switzerland
CSEM is a private applied research and development center specializing in micro-technology, system engineering, micro-electronics, and communications technologies. One of their latest projects is working on minimizing the weight of satellite attitude control systems as every gram of payload matters when launching a satellite into orbit (€15,000 ...
Modeling Scar Effects in Electrical Spinal Cord Stimulation
Kris Carlson, Dr. Jay Shils & Dr. Jeffrey Arle Lahey Clinic Burlington, MA
The Neuromodulation Group at Lahey Clinic conducted a study based upon spinal cord stimulation (SCS). SCS involves implanting a series of electrodes that apply electric potential to the spine, interfering with pain signaling circuitry. It’s used to alleviate chronic back and leg pain. Although the treatment remains effective for years, the ...
E-core Transformer Using Multi-Turn Coil Domains
This is the transient model of a single phase E-core transformer using a Multi-Turn Coil Domain. The model includes the effect of a nonlinear B-H curve in the core and shows how to connect the transformer model to the external circuits using Electric Circuit interface. The simulation is performed for two different cases; the first one with a unity ...
The Magnetic Field from a Permanent Magnet
As an example of a magnetostatic problem, consider how to model a horseshoe-shaped permanent magnet. One way is to treat the entire magnet as a ferromagnetic material, where the two end sections are defined as being pre-magnetized in different and opposite directions. An alternative is to set surface currents on the pre-magnetized parts. In this ...
Inductive Heating of a Copper Cylinder
The induced currents in a copper cylinder produce heat that in turn change the electrical conductivity. This means that the field propagation has to be solved simultaneously with the heat transfer through the cylinder and surrounding system. This model shows this coupling between eddy currents are heat transfer as a tutorial example.
Modeling of a 3D Inductor
Inductors are used in many applications for low pass filtering or for impedance matching of predominantly capacitive loads. They are used in a wide frequency range from near static up to several MHz. An inductor usually has a magnetic core to increase the inductance, while keeping its size small. The magnetic core also reduces the electromagnetic ...
Inductor in an Amplifier Circuit
This model shows how to combine an electric circuit simulation with a finite element simulation. The finite element model is an inductor with a nonlinear magnetic core and 1000 turns, where the number of turns is modeled using a distributed current technique. The circuit is imported into COMSOL Multiphysics as a SPICE netlist, which merges the ...
Electron Beam Diverging Due to Self Potential
When modeling the propagation of charged particle beams at high currents, the space charge force generated by the beam significantly affects the trajectories of the charged particles. Perturbations to these trajectories, in turn, affect the space charge distribution. The Charged Particle Tracing interface can use an iterative procedure to ...
Mutual Inductance and Induced Currents in a Multi-Turn Coil
The mutual inductance and induced currents between a single turn primary and twenty turn secondary coil in a concentric coplanar arrangement is computed using a frequency domain model. The secondary coil is modeled using a homogenized approach which does not explicitly consider each turn of the coil. The results are compared against analytic ...
A Tunable MEMS Capacitor
In an electrostatically tunable parallel plate capacitor, the distance between the two plates can be modified by a spring, as the applied voltage changes. For a given voltage difference between the plates, the distance of the two plates can be computed, if the characteristics of the spring are known. Knowledge of this means that the distance ...