Matrix Computation Tab Settings for Transient Solutions
Maxwell 2D/3D provides an option on the Matrix Computation tab for computing the inductance matrix for transient solutions. When the Compute inductance matrix option is selected, the computed matrix quantities will be available at all timesteps. The matrix quantities are listed in the reporter and thus are available for postprocessing, output variables creation, and optimetrics studies.
- Eddy effects for all objects are turned off even if Eddy Effect is checked in the Set Eddy Effects window. However, the field solution and all other results will consider the eddy effects as set in the interface.
- For a field system with multiple stranded windings, after all nonlinear materials are frozen, one winding is supplied with 1 A DC current while the other winding is open (all other sources are turned off).
The size of the computed inductance matrix is equal to the number of winding setups, that is, the matrix will be N x N when there are N winding setups; and the total number of inductance-related quantities will be N2. Components of the full matrix are available for plots and optimetrics calculation even though the matrix will always be symmetric. You can choose to access only the upper right half of the matrix by selecting the corresponding quantities as listed in the reporter dialog box. For example, the upper half of a 2 x 2 matrix will be the L11, L12, and L22 quantities.
Maxwell 2D/3D provides two Matrix Computation methods for calculating the inductance of windings for transient solutions: Apparent and Incremental.
- Apparent inductance is defined as the ratio of flux to current at a certain operating condition. Alternatively, this can be expressed as the slope of a line from the origin to the operating point on the BH curve. Apparent inductance is commonly used in nonlinear magnetic applications and in circuit analysis, and is the default method used by Maxwell.
- Incremental inductance is defined as the ratio of delta flux to delta current at a certain operating condition. This is equivalent to the slope of the tangent to the BH curve at the operating point. Incremental inductance is commonly used in physical design because it is easy to measure.
To enable the matrix computation for transient solutions:
- Click Maxwell > Design Settings.
- Alternate method: In the Project Manager tree, right-click <Design_name>, and select Design Settings.
The Design Settings window appears. You can also view and set design settings by selecting the current design, and then in the Properties window, select the tab for the solver.
- On the Matrix Computation tab, select Enable, and select the desired method: Apparent or Incremental.
- The default is NOT to compute the inductance matrix. Changing the setting for an existing design does not affect the solution for the previous simulation. For example, if a transient solve setup has 1 second set as the end time and is solved with the Enable option off (unchecked) and a plot of matrix quantities is created vs. time, the plot will not show any values because no matrix quantities were computed. Subsequently, if the compute option is enabled (checked) and the end time extended to 2 seconds, after simulation, matrix quantities will be available from > 1 second to 2 seconds, at all solved timesteps.
- If you change the computation method after solving, all matrix results of both AdaptivePass and LastAdaptive solutions will be invalidated. Then, on the next simulation, the matrix of the last solved pass will be recomputed with the new method. If there are matrix expression caches for the AdaptivePass solution, then the cached values of previous passes will not be available because only the last pass is re-simulated.
- Optionally, if you check Save as default, newly inserted designs will use the specified setting.
- When finished changing settings, click OK.