Summary for: ExtrudedBlockCircuit < Circuit

Class summary

ExtrudedBlockCircuit Circuit for massive conductor blocks.

The ExtrudedBlockCircuit class is used for modelling eddies in permanent magnets and other massive conductors. The eddy-current density and losses are computed with a hybrid 2D-3D model, making it possible to model the effects of axial segmentation.

The class extrudes the mesh of each Conductor in it into the z-direction, and discretizes the electric scalar potential on the extruded mesh. Only one axial segment is modelled, and the computed losses are then multiplied by this.volume_multiplier.

  • 9 layers are used by default. Specify dimensions.number_of_extruded_layers to adjust. In case of second-order meshes, the number is adjusted to conform to the requirements. Importantly, each element layer will have a mid-layer of nodes, so the number of mesh element layers will be roughly halved.

The resulting eddy-current density is (close to) z-directional in the first layer of the extruded mesh, and close to xy-directional in the top layer.

Properties

.block_height The segment height in the axial direction. Input

dimension.

Axial length of a magnet segment, so should be dim.leff / some_integer.

NOTE: This property must, in general, by set manually (some built-in geometry templates do it for you). If not set, it defaults to this.get_dimension(‘extruded_block_height’) IF set, and this.get_dimension(‘leff’) as a fallback.

.conductor_volume_multiplier Volume multiplication factor.

Multiplication factor between discretized conductor volume and total conductor volume in the physical machine. Equal to this.effective_length / this.discretized_segment_height * … this.root.symmetrySectors

.discretized_segment_height Height of extruded mesh.

Intended for class-internal use only - think thrice before modifying.

In this class, discretized_segment_height = 0.5 * block_height, due to symmetry.

Methods

Class methods are listed below. Inherited methods are not included.

.get_matrices Get circuit matrices for a particular problem

.init Initialize matrices etc. for circuit.

.losses Compute losses.

[Wmean, loss_data] = losses(this, solution) [Wmean, loss_data] = losses(this, solution, plot_results)

  • solution : a MagneticsSolution

  • plot_results : plot current density, boolean. Default: false.

Returns:

  • Wmean : mean losses, averaged over CircuitBase.indices_to_average_losses_over(solution)

  • loss_data : a structure.

The following loss data is returned:

  • mean_losses_per_conductor : as the name says.

  • conductor_loss_waveform : also self-evident.

  • J : current density in the extruded mesh elements. Only calculated if the ‘compute_J’ keyword argument is given OR plotting is on. The returned value is either the z-component of the induced current density in one layer of extruded elements, OR the 3D current density vector. The same current density is used for visualizations, see below.

[Wmean, loss_data] = losses(this, solution, true, args) with the following key-value pairs:

  • plotting_style : “2D” only, for now.

  • plot_layer : If plotting_style == “2D”, this specifies the layer of the extruded mesh, in which the z-component (out-of-plane) of the induced current density is visualized. The argument is passed on to this.matrices.m3data(index).m3d.elements_in_layer(plot_layer); by default the value can an integer or “mid” or “top” to plot the mid or top layer respectively.

  • steps : list of time-steps to plot. Must be >= 2. Defaults to all steps plotted.

  • axlims : axis limits to use for plotting.

  • Jlim : current density limits for the color axis (caxis)

  • plot_rms : only plot rms current density. Defaults to false.

  • compute_J : compute and return the current density.