Calculation of Motor's Ld and Lq Tab

Setting Item

Notes

Characteristics to Calculate

Ld and Lq

Calculates the Inductances Ld of the d-axis, Lq of the q-axis, and the mutual inductance Ldq and lqd of the dq-axis.

Calculation is executed with the specified timesteps.

Lu, Lv, and Lw

Calculates the 3-phase inductance matrix elements Lu, Lv, Lw, Luv, Lvw, and Lwu.

Calculation is executed with the specified timesteps.

The Settings Required for Calculation

• Definition of the model form

• Definition of the body attribute and material property

• Definition of the boundary condition

• Definition of the analysis conditions other than transient analysis tab

• Definition of the external circuit
  Layout of FEM coils, line connection, and parameter setting
  Layout of 3-Phase AC power and the following parameters
  Waveform Type
  Phase sequence

• The FEM coils on the external circuit must be 3 (one each for U, V, and W).

• If more than three FEM coils are needed, set the analysis model as follows.
  If the coils are to be connected in series:
  For the body attribute, go to [Current tab] > [Coil Name on Circuit], and assign the same name to all.
  The resistance of the FEM coils must be set as the sum of coils connected in series.
  If the coils are to be connected in parallel:
  Use period symmetric model that will not require the parallel connection of coils on the external circuit.
  There are no other methods than this to perform analysis.

Coil Name on the External Circuit

Specifies coil names of FEM components in the external circuit for U coil, V coil, and W coil of the 3-phase AC unit.

Angle of d-axis to u-axis

Used for calculating Ld and Lq.

Sets the angle of d-axis to u-axis at the initial time.

With reference to the u-axis, if the d-axis is advanced, set the positive value. If it is behind, set the negative value.

• [Rotor's Initial Rotation Position] on the rotating machinery tab is taken into account.
  [Rotor's Initial Rotation Position] may be set so as to make the angle 0.

Definition of Each Axis

d-axis: Center axis of permanent magnet (magnetic flux direction generated by magnetic pole)

q-axis: Axis between permanent magnets (axis magnetically crossing the d axis at the right angle)

u-axis: Magnetic flux direction generated by U-phase coil

Example

In the diagram below, the mechanical angle of the d-axis to the u-axis is -15[deg].

Timesteps to calculate

Sets the number of timesteps for various calculations.

The more number of timesteps, the longer the calculation time.