19.9.9. Inductance

Inductance can be computed for conductor bodies. It is defined as a measure of the differential change in flux linkage to the differential change in current. This is represented by the equation below, where dψ is the differential change in flux linking conductor j produced by a differential change in current for conductor i. Note that this is valid for linear and nonlinear systems, the inductance will be a function of current.

Inductance is often used as a parameter in electric machine design and in circuit simulators.

A conductor body must have a current load to be considered in inductance calculations. Inductance results are presented in the Worksheet View. The results are presented in table form. The example below shows inductance results for a two-conductor system. The diagonal terms represent self-inductance, while the off-diagonal terms represent mutual inductance. In this case, L11 = 1e - 4, L22 = 8e - 4, L12 = L21 = 4e - 4 Henries.

 Cond1 (H)Cond2 (H)
Cond11e-44e-4
Cond24e-48e-4

The Details view for inductance allows you to define a Symmetry Multiplier. Use this if your simulation model represents only a fraction of the full geometry. The multiplier should be set to compensate for the symmetry model. For example, if you create a half-symmetry model of the geometry for simulation, set the Multiplier to '2.' Changing the multiplier will update the Worksheet results.


Note:
  • Computing inductance can be time-consuming and should only be used if needed.

  • Loads (Voltage, and Current) must be constant when Inductance is specified. Tabular and function loads are not supported.

  • Inductance can only be used with a single step, single substep solution. User settings to the contrary will be overridden.

  • Inductance requires the Direct solver setting (default) for the Solver Type property of Analysis Settings. User settings to the contrary will be overridden.