Excitation Coil Lumped Parameter Model Reference

The Excitation Coil Lumped Parameter model allows you to extract the lumped parameters of a coil region, that is, the coil resistance and inductance.

When you use this model in combination with the Circuit Model, you can define the load on excitation coil circuit elements using the extracted lumped parameters. See Creating Electric Circuits.


Model Name	Excitation Coil Lumped Parameter
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Excitation Coil Lumped Parameter
Requires	Physics Models: Space: one of Two Dimensional, Axisymmetric, Three Dimensional Time: Implicit Unsteady Material: one of Solid, Multi-Component Solid > Multi-Part Solid Optional Models: Electromagnetism Electromagnetism: either Finite Element Magnetic Vector Potential (for three-dimensional simulations) or Transverse Magnetic Potential (for two-dimensional simulations) Other Models: either Excitation Coil or Finite Element Excitation Coil
Activates	Reports	When used together with the Finite Element Magnetic Vector Potential model, the Excitation Coil Lumped Parameter model activates the following reports: Magnetic Inductance Magnetic Motion Induced Voltage Regularized Magnetic Flux Linkage See Reports.
	Solvers	Excitation Coil Lumped Parameter (uses either the Sparse Direct Solver or the Iterative solver. See Excitation Coil Lumped Parameter Solver)
	Field Functions	Excitation Coil Load, Specific Magnetic Flux Linkage, Magnetic Vector Potential.

Reports

The following reports are available when you activate either the Finite Element Magnetic Vector Potential or the Transverse Magnetic Potential model.

All reports accept either coil regions or their associated coil circuit element as inputs. When evaluating a report for a circuit element, Simcenter STAR-CCM+ takes into account the circuit element Periodicity Factor and returns the total value for the whole configuration. Therefore, these reports can return different values for a region and its associated circuit element.

Magnetic Inductance

Calculates either the self-inductance of a coil (or group of coils), or the mutual inductance between two coils (or groups of coils). To calculate the self-inductance, you specify the relevant coils using the Parts property, leaving the Parts Mutual property blank. To calculate the mutual inductance, you specify the first coil (or group of coils) using the Parts property and the second coil (or group of coils) using the Parts Mutual property.

When using the Finite Element Magnetic Vector Potential model, this report requires the coil local direction field to be divergence-free (see Eqn. (4333)). This requirement is not necessary when using finite volume models such as the Finite Volume Magnetic Vector Potential model.

The report accuracy depends on the accuracy of the local direction field. Coarse meshes can cause the divergence of the local field to be non-zero. In this case, you can either refine the mesh in the coil region or use a surface integral report for the magnetic flux density in the coil region.

Alternatively, you can also use a volume integral report for the [Region_Name] Specific Magnetic Flux Linkage field function (see Field Functions).

Magnetic Motion Induced Voltage

Calculates the voltage induced in an excitation coil by motion. For this report, you set the input Parts to one or more coil regions for which you want to calculate the induced voltage. If you define a coil region using part sub-grouping, make sure each sub-group in the region has an identical Electric Current defined under the Electrical Current Density Magnitude > By Part Subgroup > [Subgroup] > Ampere Turn node.

To calculate the voltage, Simcenter STAR-CCM+ takes into account the contributions from all moving regions in the simulation, with the following requirements:

Moving regions that are subject to electromagnetic force must be surrounded by a force-free medium (see Magnetic Force). Additionally, these regions must move with rigid motion (either Rotation, Translation, or Rotation and Translation motion. See Prescribing Rotations and Translations).
Moving regions that are force-free are allowed to move with any motion type, as their motion does not contribute to the induced voltage.

Regularized Magnetic Flux Linkage

Calculates the magnetic flux linkage in the coil (see Eqn. (4338)). Specify the regions that you want to include in the report. Optionally, activate Smooth Values to interpolate reported values to the mesh vertices. By default, this option is Off and the report uses the values in the closest cell centroid. When you select the Finite Element Magnetic Vector Potential model together with the Excitation Coil model (instead of the Finite Element Excitation Coil model), this report is the preferred method for calculating the magnetic flux linkage.

Excitation Coil Lumped Parameter Solver

The Excitation Coil Lumped Parameter solver calculates the coil solution using either a direct or an iterative solution method. Simcenter STAR-CCM+ automatically chooses between the direct and the iterative method based on the following:

If the simulation contains the Transverse Magnetic Potential solver, the Excitation Coil Lumped Parameter automatically uses the Sparse Direct Solver.
If the simulation contains the finite element Magnetic Vector Potential solver, the Excitation Coil Lumped Parameter solver uses the same type of solver (either the Sparse Direct Solver or the Iterative solver) that is used by the Magnetic Vector Potential solver. To specify the solution method (direct or iterative), you set the Solver Method property for the Magnetic Vector Potential solver node. For more information, see Magnetic Vector Potential Solver: Solver Method.
For calculation of the excitation coil solution, the direct solution approach is more efficient, as no additional factorization is required. The iterative solution approach is suitable for simulations that require the use of an iterative solver to solve for the magnetic vector potential.

In general, the excitation coil iterative solver requires a low value for the Convergence Tolerance (see FE Iterative Solver Reference), regardless of the presence of nonlinear materials in the simulation. For this reason, the default value for the convergence tolerance for the excitation coil iterative solver is lower than the default convergence tolerance of other solvers. In general, the default value is appropriate.
For simulations that contain both the Transverse Magnetic Potential and the finite element Magnetic Vector Potential solvers, the Excitation Coil Lumped Parameter solver contains two child solvers (either two sparse direct solvers, or one direct solver and one iterative solver, depending on the settings for the Magnetic Vector Potential solver). These child solvers are associated with the relevant magnetic potential solver and calculate the lumped parameters independently in the corresponding regions.

For more information on solver properties and controls, see either FE Sparse Direct Solver Reference or FE Iterative Solver Reference.

Field Functions

[Region_Name] Excitation Coil Load: Represents the current load in the coil region.
[Region_Name] Specific Magnetic Flux Linkage: Represents the coil region inductance. This field function is different from the Specific Magnetic Flux Linkage field function activated by the Excitation Coil model. See Excitation Coil Model Reference.
[Region_Name] Magnetic Vector Potential: Represents the magnetic vector potential solution corresponding to the region load.
[Region_Name] Magnetic Flux Density: Represents the magnetic flux density corresponding to the region load.