Variable Capacitor
Purpose
Variable capacitor.
Library
Electrical / Passive Components
Description
This component models a variable capacitor. The capacitance is determined by
the signal fed into the input of the component. The current through a variable
capacitance is determined by the equation

Therefore, the control signal must provide the values of both
and
in the
following form:
. It is the responsibility of the
user to provide the correct derivatives.
If the component has multiple phases you can choose to include the capacitive
coupling of the phases. In this case the control signal vector must contain the
elements of the capacitance matrix (row by row) and their derivatives with respect to
time. The control signal thus has a width of
,
being the number of phases.
Note
- The momentary capacitance may not be set to zero. In case of coupled
capacitors, the capacitance matrix may not be singular.
- The control signal for the momentary capacitance values must be
continuous. Discontinuous changes will produce non-physical results.
Parameters
-
Capacitive coupling
- Specifies whether the phases should be coupled capacitively.
This parameter determines how the elements of the control signal are
interpreted. The default is off.
-
Initial voltage
- The initial voltage of the capacitor at simulation start, in volts
(V). This parameter may either be a scalar or a vector corresponding to the
implicit width of the component. The positive pole is marked with a "+". The
initial voltage default is 0.
Probe Signals
-
Capacitor voltage
- The voltage measured across the capacitor, in volts (V). A
positive voltage is measured when the potential at the terminal marked with
"+" is greater than the potential at the unmarked terminal.
-
Capacitor current
- The current flowing through the capacitor, in amperes (A).