Software for Computational Electromagnetics Modeling

Image made using the COMSOL Multiphysics® software and is provided courtesy of COMSOL.

COIL MODELING: The model shows a 50-Hz AC coil wound around a ferromagnetic core. The complex coil winding geometry can be easily modeled using a multiturn coil feature. Visualization shows the magnetic flux density (arrow plot) and the magnetic flux density norm on the ferromagnetic core.

The AC/DC Module is used for simulating electric, magnetic, and electromagnetic fields in static and low-frequency applications. Typical applications include capacitors, inductors, insulators, coils, motors, actuators, and sensors, with dedicated tools for extracting parameters such as resistance, capacitance, inductance, impedance, force, and torque.

Materials and constitutive relations are defined in terms of permittivity, permeability, conductivity, and remanent fields. Material properties are allowed to be spatially varying, time-dependent, anisotropic, and have losses. Both electric and magnetic media can include nonlinearities, such as **B-H** curves, or even be described by implicitly given equations.

The AC/DC Module grants you access to a set of essential boundary conditions such as electric and magnetic potential, electric and magnetic insulation, zero charge, and field and current values as well. In addition, a range of advanced boundary conditions are included, such as terminal conditions for connection with SPICE circuits, floating potentials, conditions for symmetry and periodicity, surface impedance, surface currents, distributed resistance, capacitance, impedance, and contact resistance. For modeling unbounded or large modeling domains, infinite elements are available for both electric and magnetic fields. When an infinite element layer is added to the outside of a finite-sized modeling domain, the field equations are automatically scaled. This makes it possible to represent an infinite domain with a finite-sized model and avoids artificial truncation effects from the model boundaries. For electrostatics modeling, the boundary element method is available as an alternative method of modeling infinite regions.

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- Bioheating
- Circuit parameter extraction (R ,L, Z matrices)
- Combined SPICE circuit and field simulations
- Contact resistance
- Current and field distribution and visualization

- Electric displacement field and dielectric stress
- Electromagnetic force and torque
- Electromagnetic shielding
- Electromechanical deformation
- Induction heating

- Lorentz force computation
- Nonlinear materials including
**B-H**curves - Parasitic capacitance and inductance
- Porous materials
- Resistive heating

- Coils and solenoids
- Electric welding
- Electric insulation
- Electromagnetic compatibility (EMC)
- Electromagnetic interference (EMI)
- Electromagnetic shielding

- Electromechanical machinery
- Electronics reliability and electromigration
- Induction furnaces
- Induction logging
- Insulators, capacitors and dielectrics

- Motors, generators and other electromechanical machinery
- Permanent magnets and electromagnets
- Plungers
- Sensors
- Transformers and inductors

Induction heating is a method used to heat metals for forging and other applications. Compared with more traditional heating methods, such as gas or electric furnaces, induction heating delivers heating power directly to the piece in a more controlled way and allows for a faster processing time.

The Induction Heating of a Steel Billet application can be used to design a simple induction heating system for a steel billet, consisting of one or more electromagnetic coils through which the billet is moved at a constant velocity. The coils are energized with alternating currents and induce eddy currents in the metallic billet, generating heat due to Joule heating. The billet cross section; the coil number, placement, and size; as well as the initial and ambient temperature and the individual coil currents can all be specified as inputs in the app.

After the solution has been computed, the app plots the billet temperature and current density during the processing. Furthermore, it computes numerical data on the expected temperature ranges in the billet and the power balance of the system.

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 inductor model and the circuit elements as ODEs.

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 and heat transfer as a tutorial example.

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 efficiently compute the strongly coupled particle trajectories and electric field for systems operating under steady-state conditions. Such a procedure reduces the required number of model particles by several orders of magnitude, compared to methods based on explicit modeling of Coulomb interactions between the beam particles. A mesh refinement study confirms that the solution agrees with the analytical expression for the shape of a nonrelativistic, paraxial beam envelope.

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 between the plates can be tuned via the spring.

In this model, the electrostatic field is simulated out for a given distance.

Magnetic prospecting is a geological exploration method that is applicable to certain types of iron ore deposits, in particular those made up of magnetite and hematite. The method consists of measuring the magnetic anomalies (changes in the earth’s magnetic field) due to the presence of magnetic ores.

The Magnetic Prospecting app simulates the effect of a deposit of magnetic ore on the earth’s magnetic field and predicts the measured anomaly at specified measuring points on the surface. You can import heightmap images or digital elevation model (DEM) files to define the orography of the region as well as the geomagnetic field data for the specified location.

The computation generates a plot of the magnetic field on the earth’s surface as well as numerical data of the expected anomaly at specified measurement locations in the region.