MaterialBase

Summary

MaterialBase Base class for materials.

Not really used right now, see Material.

PROPERTIES

B - given B-curve (T)
H - given H-curve (A/m)
domains - list of domains that are made of this material
elements - indices to finite elements
iron_loss_computation_method Iron loss computation method.

This property allows an option to toggle the iron loss computation method. Indeed, the loss_density method of the Material class calls the method with its name equal to this property.

However, subclasses may have a different loss_density method.

is_symmetric - Is the differential reluctivity symmetric?
material_properties Struct of material properties

Important fields include:

rho : material density, kg/m^3
coeffs : [hysteresis, eddy, excess] loss coefficients, defined as W/kg at 50 Hz and 1 T, with B-f dependencies as ~[fB^2, (fB)^2, (fB)^.1] respectively. Used mainly in the Material class.
plot_args - plotting instructions for this

Methods

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

* MaterialBase Base class for materials.

Not really used right now, see Material.

* MaterialBase/detach is a function.

* MaterialBase/differential_reluctivity is a function.

* get_B_data Compute flux density waveforms and other data.

Bdata = get_B_data(solution, args)

Bdata is an array of structs with the fields (one struct per quadrature point)

solution : handle to the MagneticsSolution used
timestamps : time-step timestamps in seconds

** volume_multiplier : model.dimensions.leff ** model.symmetrySectors

DETF : absolute value of mesh mapping matrix determinant at quad point
Bx : waveform of x-component of flux density at quad point
By : waveform of y-component of flux density at quad point

* MaterialBase/init_for_problem is a function.

* loss_density Iron/material loss density method.

[p_hysteresis, p_eddy, p_excess] = loss_density(this, Bdata), where

Bdata : flux density waveform data returned by get_B_data .

Return values:

Elementwise hysteresis, eddy, and exces loss densities, expressed in W/m^3.

* losses Material-level loss computation.

[Ptot, Pdata] = losses(solution) or

[Ptot, Pdata] = losses(solution, key, value, …) (see below)

return the total material (usually iron) losses Ptot for MagneticsSolution solution.

Pdata is then a struct with the following fields:

Return values: total losses (time-average) and a loss data struct with the following fields:

P_total : average total losses
P_total_time : total losses versus time (solution.ts)
P_hysteresis : total hysteresis losses
P_eddy : total eddy-current iron losses
P_excess : total excess losses.
P_rotor : total losses in rotor (in elements motor.rotel)
P_hysteresis_rotor : total hysteresis losses in rotor
P_eddy_rotor
p_hysteresis_elementwise : vector of elementwise hysteresis loss density (W/m^3)
p_eddy_elementwise
p_excess_elementwise

WARNING: element-wise loss densities are returned in W/m^3, as opposed to the W/kg used in previous versions.

The losses are computed by first computing the flux density waveforms with MaterialBase.get_B_data, and then passing the results to the .loss_density method of each Material in the solution, to get the elementwise loss densities. The losses are then summed and the other interesting outputs computed.

Keyword arguments:

plotting_on : plot results (default false). Losses are plotted with MaterialBase.plot_losses
remove_DC : Remove DC-component of flux density before computing losses? Options: false - no removal / ‘rotor’ - only remove from rotor elements (motor.rotel) / ‘all’ remove from all elements.
use_entire_solution : use entire solution range (in time-domain). Default: false: only last full electrical period is used.
method : This value is temporarily set as the iron_loss_computation_method property of each Material. For the plain Material class, the options are “iron_loss_density_time_domain_Steinmetz” and “iron_loss_density_frequency_domain_Bertotti”. Subclasses may ignore this. Default : [] –> don’t change the property value.