17.exporting equivalent circuit data.pdf

Exporting Equivalent Circuit Data

You can export lumped R, L, C data from a Maxwell solution to Ansoft SIMPLORER or Saber format. Importing the new data file to SIMPLORER or Saber enables you to include wave effects in the circuit simulations.

An equivalent circuit can be exported from a parametric solution or from an imported table.

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Note You can only export an equivalent circuit from a parametric solution when the following two criteria are met:

• The solution type is Magnetostatic or Electric.

• A parametric setup exists.

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Exporting a Circuit From a Parametric Solution

To create a circuit from parametric solutions, you first need to set up and solve a problem that contains a parametric sweep. Any force, torque, and matrix solutions are automatically available to use in the equivalent circuit. Other solutions can be treated as extra inputs/outputs if they have been added as calculations in the parametric setup — that is, extra inputs/outputs come from the parametric table.

To export a circuit from a parametric solution:

1. Click Maxwell3D>Export Equivalent Circuit>From Parametric Solutions or Maxwell2D>Export Equivalent Circuit>From Parametric Solutions.The General window appears, allowing you to specify basic information about the circuit model.

2. Select one of the following from the Model Type pull-down list depending upon the Design Type(2D or 3D):

• Linear Motion

Note In Maxwell, global variable names begin with the $ character. However, when you are creating an ECE .sml model, this character causes the circuit to fail when importing it to SIMPLORER. To resolve this, when the circuit is exported, the $ character is replaced by the _ character. For example, the project variable $MyVar is converted to _MyVar.

Note This command is enabled only when the following two criteria are met:

• The solution type is Magnetostatic or Electric.

• A parametric setup exists.

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• Transformer

• Matrix

• Lookup Table

3. Select a Parametric Setup from the pull-down list.

4. Select a Solution Setup from the pull-down list.

5. Select a Matrix Setup from the pull-down list.

6. Select a Force Setup or a Torque Setup from the pull-down list, depending on which parameter you have set up for your design.

7. For the force or torque setup, select X, Y, or Z as the Component.

8. Select either Ampere-Turns or Amperes as the Current Source Variables option.

9. Click Next.The Table window appears, allowing you to set up the inputs and outputs for the circuit equivalent. Most of the values have been automatically filled in, based on your design. You can keep the defaults or change the selections and values for the various parameters.

10. To export the data to a table that you can edit and use to export an equivalent circuit at a later time, do the following:

a. Click Export Table.The Save As dialog box appears.

b. Select a location, and type a name in the File name box.

c. Click Save.The Table window reappears. The file that is created contains header rows with information such as name, i/o, and type, plus all of the actual data. You may export the table to view or use in external programs. You can also modify the exported table file and then re-import it to create an equivalent circuit. On import, the information in the header rows is used as default settings in the circuit export dialog box.

11. To apply deep spline interpolation to all inputs in the circuit PWL model, select the Use Bezier Interpolation check box.

12. For model types Linear Motion, Transformer and Matrix, click Next.

The Terminals window appears, allowing you to set up terminals, which are nodes with "through" and "across" data. Most of the values have been automatically filled in, based on your design. You can keep the defaults or change the selections and values for the various parameters.

1. Enter a Scaling Factor in the text box. The scaling factor is applied to all output quantities and can be used, for example, to scale data from partial models that take advantage of symmetry.

2. Optionally, specify the Model Depth for 2D XY models for scaling.

3. Specify the Terminals:

• To specify a coil terminal:

Note The Table window is the last step for the Lookup Table model type. For all other model types, there is one more step: the Terminals window.



a. Select a Source for the Flux or Charge, depending on whether your design is mechanical or electrical.

b. Enter a Resistance.

c. Enter the number of Turns in the coil winding.

d. Enter the number of Branches.

• To specify a mechanical terminal:

a. Select the Force or Torque variable from the pull-down list.

b. Select the Position or Rotation variable from the pull-down list.

4. Click Finish to export the equivalent circuit.


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Exporting Equivalent Circuit Data >

Exporting a Circuit From a Parametric Solution

Types of Equivalent Circuit Models

Currently, you can generate the following model types:

• Linear Motion - Models inductance (or capacitance) and force as functions of current (or voltage) and position. The parametric solution should cover the range of motion and conductor current (or voltage).

• Transformer - Models nonlinear mutual inductance with a leakage inductance branch for each coil. The parametric solution should cover the range of current for one coil in an open-circuit test.

• Matrix - Models an inductance or capacitance matrix for one or more conductors, as a function of current or voltage. The parametric solution should cover the range of each conductor’s current or voltage.

• Lookup Table - This option creates a lookup table model in either Simplorer or Saber formats.


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Exporting a Circuit From an Imported Table

To create a circuit from an imported table, you need to have a table file containing tabular data. The first row in the file must contain the column names. The table export feature writes other useful information into subsequent rows, but the import succeeds whether or not this information is present. The rows of tabular data come next.

Note In Maxwell, global variable names begin with the $ character. However, when you are creating an ECE .sml model, this character causes the circuit to fail when importing it to SIMPLORER. To resolve



To export a circuit from an imported table:

1. Click Maxwell3D>Export Equivalent Circuit>From Imported Table or Maxwell2D>Export Equivalent Circuit>From Imported Table.The Select File dialog box appears.

2. Find and select the file containing the table you want to use.

3. Click Open.The General window appears, allowing you to specify basic information about the circuit model.

4. Select one of the following from the Model Type pull-down list:

• Linear Motion

• Matrix

• Lookup Table

5. Enter a Scaling Factor in the text box. The scaling factor is applied to all output quantities and can be used, for example, to scale data from partial models that take advantage of symmetry.

6. Select either Ampere-Turns or Amperes as the Current Source Variables option.

7. Click Next.The Table window appears, allowing you to set up the inputs and outputs for the circuit equivalent. Most of the values have been automatically filled in, based on your design. You can keep the defaults or change the selections and values for the various parameters.

8. To export the data to a table that you can edit and use to export an equivalent circuit at a later time, do the following:

a. Click Export Table.The Save As dialog box appears.

b. Select a location, and type a name in the File name box.

c. Click Save.The Table window reappears. The file that is created contains header rows with information such as name, i/o, and type, plus all of the actual data. You may export the table to view or use in external programs. You can also modify the exported table file and then re-import it to create an equivalent circuit. On import, the information in the header rows is used as default settings in the circuit export dialog box.

9. To apply deep spline interpolation to all inputs in the circuit PWL model, select the Use Bezier Interpolationcheck box.

10. For model types Linear Motion, Rotational Motion, and Matrix, click Next.

The Terminals window appears, allowing you to set up terminals, which are nodes with "through" and "across" data. Most of the values have been automatically filled in, based on your design. You can keep the defaults or change the selections and values for the various parameters.

• To specify a coil terminal:

this, when the circuit is exported, the $ character is replaced by the _ character. For example, the project variable $MyVar is converted to _MyVar.

Note The Table window is the last step for the Lookup Table model type. For all other model types, there is one more step: the Terminals window.



a. Select a Source for the Flux or Charge, depending on whether your design is mechanical or electrical.

b. Enter a Resistance.

c. Enter the number of Turns in the coil winding.

d. Enter the number of Branches.

• To specify a mechanical terminal:

a. Select the Force or Torque variable from the pull-down list.

b. Select the Position or Rotation variable from the pull-down list.

11. Click Finish to export the equivalent circuit.


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Setting Up Current Variables

For problems with current, the Current Variables Represent setting allows you to specify one of the following two options:

• Ampere-Turns

• Amperes

This setting provides flexibility in setting up current sources with different numbers of turns and branches.

In Maxwell, current source values are specified in Ampere-turns, meaning that if a given source is driven with 2 Amps through 100 turns, then the source value must be set to 200. Inductance is calculated per-turn; therefore, to calculate EMF, the flux must be scaled by the number of turns to give the total flux.

You can create two kinds of circuit models:

• A model format where the data table is based on current in Amp-turns and flux per turn. This model internally converts currents and fluxes using the specified turn ratio. This model format was the only one available in versions of Maxwell before Maxwell 11.

• A model format where the data table is based on current in Amps and total flux. This model does no internal scaling of values, since the data is already in a form the outside circuit expects. This model format is available in Maxwell 11 and later versions.

For either model type, you can view the inductance setup to obtain information about the specified groups, turns, and branches.




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Current Variables Represent Ampere-Turns

How to use this format:

• Apply variables directly to sources. Source1 value = Current1.

• Sweep variable values in Ampere-turns. Current1 sweeps from 100 to 200.

• In an inductance setup, specify the number of turns consistent with the source setup. Make sure all sources in a group have the same number of turns.

When to use this format:

• If all sources in a group have the same number of turns.

• If you want to be able to modify the number of turns in the exported circuit.

• If you are more comfortable thinking of variables in Ampere-turns.

When using this format, the grouping is taken from the inductance setup. The number of turns and branches per group from the inductance setup are used as a default but can be modified either before exporting the circuit or in the exported circuit.


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Current Variables Represent Amperes

How to use this format:

• Define sources as the current variable times turns. Source1 value = 100*Current1.

• Sweep variable values in Amperes. Current1 sweeps from 1 to 2.

• In an inductance setup, specify the number of turns consistent with the source setup.

When to use this format:

• In cases where one current is applied through sources with different numbers of turns.

• If you do NOT need to modify the number of turns in the exported circuit.

• If you are more comfortable thinking of variables in Amperes.

When using this format, the groups, turns, and branches are taken from the inductance setup and are used as is. You will not be able to modify them during circuit export or in the exported circuit.




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Setting Inputs and Outputs in the Table Window

The table includes rows for all of the following that are appropriate to the model type:

• Swept variables from the parametric setup.

• Components of flux or charge from the selected matrix.

• Force or torque.

• Calculations from the parametric setup.

Where possible, the columns are set with reasonable defaults based on the information from the design. In many cases, you should not have to change anything.

Additional information about the columns:

• Under I/O, the choices are Input, Output, or Unused. Unused means that the quantity will not be included in the circuit.

• Under Type, the choices are Position, Rotation, Current, Voltage, Flux, Charge, Force, Torque, and Other. These choices affect the terminal setup in the next window. Other is typically used for extra inputs/outputs.

• Under Extrapolate, the choices are all standard extrapolations plus None. For inputs, the Extrapolate column is automatically set to None and is disabled.

Linear This option takes the last two points of the data and generates a straight line extending beyond the range of the parametric sweep.

Periodic repeat the data outside the range of the parametric sweep.



HalfPeriod mirror then repeat the waveform outside the range of parameter sweep.

Constant extrapolate a constant value from the last point in the interpolation.

Even repeat the wave outside the range of parametric sweep.

Odd repeat a reflection of the waveform outside the range of the parametric sweep.




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Setting Coil and Mechanical Terminals

There are currently two types of terminals:

• Coil Terminals

• Mechanical Terminals

For models with motion, the mechanical terminal setup determines which force (or torque) causes the motion and which position (or rotation) is affected.

When setting up coil terminals, flux and current are used for magnetic models, and charge and voltage are used for electric models.

In the coil terminal setup, there is one row for each flux (or charge) group. In the Current (or Voltage) column, each cell is a selection box where you can choose the current (or voltage) that applies to that flux (or charge) group. Usually the software can choose the correct current by default, based on the source setup in the design. The Resistance column is set to 0 by default; you can enter any value here. The Turns and Branches columns only appear for magnetic models where current variables represent Ampere-turns. These columns are initialized with the turns and branches specified in the inductance matrix setup.

In the Current column, in addition to each current, there is another choice, <Dependent>. This feature allows you to solve some problems using fewer parametric rows. This is explained using the following example:

Suppose you are working on a three phase machine. You create three sources, CurrentA, CurrentB, and CurrentC. In previous versions of Maxwell (before version 11), you would have to create three current variables, iA, iB, and iC, and sweep all three of these variables — even though for this type of machine iC is always equal to -(iA + iB). This means that if you want to sweep through 10 values of current, the parametric table would have 1000 rows. In Maxwell 11 and beyond, you can create only variables iA and iB and then set the value of CurrentC to -(iA + iB). The parametric table will have 10 values each for iA and iB, so it will only have 100 rows. When exporting the circuit, you would set the current for Flux[CurrentA] to iA, Flux[CurrentB] to iB, and Flux[CurrentC] to <Dependent>. In the circuit model, the PWL table will contain two input currents (iA and iB), but it will contain all three fluxes. So it will look up all three flux values based on only the two current values. As long as you always connect a current of -(iA + iB) to CurrentC, this model will be valid.

Note A dependent source can have a different number of turns from the sources that it depends on (in the



example above, CurrentA, CurrentB, and CurrentC can all have different numbers of turns). But, in this case, you would have set up the current variables as Amperes instead of Ampere-turns — otherwise there would be no way to obtain the correct scaling of currents iA and iB for both their own current sources and for CurrentC. Therefore, this is another case where specifying current variables in Amperes (rather than in Ampere-turns) is useful.




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17.exporting equivalent circuit data.pdf