The RLC (Resistive-Inductive-Capacitive)
Coil Group node is an advanced coil feature that takes advantage of the A-V formulation of the Magnetic and Electric Fields features to take into account in-plane electric current flow in the coil’s current balance. This feature combines the magnetic model of a
Single Turn Coil (in Coil group mode) with a multiple-terminal electrical model for the in-plane current. This node can be used to approximate in 2D a coil in which (due to capacitive coupling or other phenomena) there is relatively significant current flow in the in-plane directions.
Apply this feature to a group of domains representing the cross sections of the coil turns on the modeling plane. Since the electric potential is assumed to be constant in the cross section of each turn, the V variable must be removed in the selected domains by applying an Ampère’s Law node. The feature applies an external current density flowing orthogonally to the plane, and also imposes a voltage constraint on the boundary of each cross section, computed from the coil and the excitation properties. The feature also enforces a balance of the current flowing out-of-plane and the current leaking in the plane between the coil turns.
with n and
m being integers. One-dimensional lattices (linear lattices) are also supported by this feature.
By default, the RLC Coil Group feature assigns the first turn index (closest to the reference potential) to the turn with the smallest n and
m. When using the automatic recognition algorithm, this usually corresponds to the coil turn with smallest
x and
y (or
r and
z in axisymmetry). The other coil turns are numbered in order of increasing
m first, and then increasing
n. Refer to the diagram in the node’s
Settings window for a visual explanation.
If Winding is set to
Alternated, the direction of increasing
m is reversed each time
n changes value. Again, refer to the diagram for a visual explanation.
The RLC Coil Group feature expands the model applied by a Single Conductor Coil domain feature by including a current balance for each turn and constraints for the voltage. The feature introduces n + 1 voltages (where
n is the number of coil turns) with the interpretation of electric potential values at the turn end terminals:
V0,
V1,...,
Vn, where
V0 is the value specified as the
Ground voltage in the
Settings window. The cross section shown in the interface corresponds to the midsection of the turns, that is half way between the end terminals. The
i-th coil turn (
i =
1,..., n) has an applied potential difference
The coil current ICoil is computed from the coil excitation in the same way as for the Single Conductor Coil feature.
The settings in this section is very similar to the ones described in the Single Conductor Coil node. The only addition is the
Ground voltage input. Specify in the text box the voltage at one end of the coil (SI unit: V). The voltage at the other end depends on the excitation type. This setting is useful, for example, to connect in series two coil groups.
This section specifies the information needed to identify the Bravais lattice on which the coil turns are placed The feature automatically detects the two primitive vectors of the lattice if Ordering is set as
Row-wise (the default) or
Column-wise. For
User defined use the diagram as a guide to manually enter the
Primitive vectors a and
b (SI unit: m) of the lattice. The diagram shows how the domains are ordered for each choice.
Select a Winding style —
Regular (the default) or
Alternated. Look at the diagram for an illustration of these options.