Summary for: RFModelWithSkew < RFmodel & SlicedMotorModel

Class summary

RFModelWithSkew Skewed and sliced radial-flux model.

See RFModelWithSkew.create_simple for typical usage.

On the implementation level, all slices are initialized and meshed origin-centric, without considering skewing. Thus, this.mesh will generally contain overlapping meshes. Virtual translations (on copies of coordinates) will be performed during plotting, while virtual rotations will be performed for different rotors during airgap matrix and torque evaluation, and plotting both.

Properties

Methods

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

.compute_torque Compute torque and forces.

[T, Fx, Fy] = compute_torque(this, solution) computes the torques and net rotor forces acting over each airgap.

Skewing is considered by overwriting the default rotor angles and using the 'rotor_angle', angles_here input syntax of SlidingAirgapBase.compute_torque.

.create_simple Create a sliced stator-rotor model.

motor = create_simple(dim, stator_class, rotor_class) creates a sliced radial-flux motor model motor with one stator and one rotor per each class. The number of slices is specified by the field number_of_slices in the dimensions struct dim.

** ** *PLEASE NOTE** Copies of the supplied geometries are created by this class. Thus, even if a valid GeoBase object is given as an input, the resulting RFModelWithSkew model with ** not contain the original geometry object as a component.

Skewing, if any, is parsed by this.set_component_angles.

Underneath, this method creates a set of RFSlice objects by calling RFSlice.Default(dim_slice, stator, rotor). The slice dimensions are otherwise a copy of dim, only the slice effective length is shorted by dim_slice.leff = dim.leff / dim.number_of_slices;. Finally, this.finalize is called.

.finalize Finalize sliced model.

This method performs the following steps

  • call the add_gaps_to_model method of each slice.
  • call the parent class (RFmodel) implementation of finalize.
  • call this.parse_sliced_circuits.
  • call this.set_component_shifts.
  • call this.set_component_angles.

.get_AGmatrix Get airgap matrix.

Similar to the MotorModelBase method, only angle-biasing is performed to account for skewing.

.— help for RFModelWithSkew/get_plot_mesh —

RFModelWithSkew/get_plot_mesh is an undocumented builtin RFModelWithSkew method.

.plot_raw_airgap_flux Plot airgap fluxes.

Similar to the MotorModelBase method, only some angle-hacking is performed to correctly account for skewing.

.set_component_angles Parse and set component angles.

set_component_angles(this) sets the bias angle for each rotor slice, to account for skewing. If this.dimensions.skew_angle is an array (of correct size), it is directly used for setting the skew angles. If it is a scalar, uniform distribution between [-0.5, 0.5]*skew_angle is used.

** NOTE: The aforementioned distribution of skew angles is appropriate for modelling step-wise skewing, such as that often found in PM rotors. For induction-motor-style continuous skewing, a better approach is to use

skew_angle ** linspace(0.5** (-1+1/Nslices), 0.5*(1-1/Nslices), Nslices)

i.e. set the skew angle of each slice to correspond to the average skew angle over that slice. This can be achieved by setting

dim.skew_type = 'continuous.

.set_component_shifts Set xy-shifts for the geometry components.

set_component_shifts(this) tries to parse suitable shifts for the components of each slice, so that the slices do not overlap during visualization.

.to_plot_frame Transform coordinates to plot frame.

In general, this function transforms coordinates and vectors from the mesh frame (origin-centric without skewing) to the plot frame, with different slices translated to avoid overlapping, with extra rotations if needed to account for skewed rotors.

Several input options are supported:

  • y = to_plot_frame(this, x) corresponding to zero-angle case.
  • y = to_plot_frame(this, x, rotor_angle) default case. The input coordinate vector is assumed to be the same size as the full mesh coordinates.
  • y = to_plot_frame(this, x, rotor_angle, component) only applies the translations and skews according to the single component given.
  • y = to_plot_frame(this, x, rotor_angle, component, “vector”) treats the input as a vector, only performing rotations and not translations.