WOLFRAM SYSTEM MODELER
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This is an ideal triac model based on an ideal thyristor model.
Two ideal thyristors (Modelica.Electrical.Analog.Ideal.IdealThyristor) are contrarily connected in parallel and additionally eliminated interference with a resistor (Rdis=100) and a capacitor (Cdis=0.005), which are connected in series.
The electrical component triac (TRIode Alternating Current switch) is, due to whose complex structure, a multifunctional applicable construction unit. The application area of this element is the manipulation of alternating current signals in frequency, voltage and/or current and also general blocking or filtering. However, compared to a thyristor the triac is only applied for substantial lesser currents, what is justified by whose sensitive structure. Generally one is limited to maximal voltages from 800 volt and currents from 40 ampere. For comparison maximal voltages of a thyristor are 8.000 volt and currents 5.000 ampere.
Structure and functionality:
Functionality of a triac is in principle the same like functionality of a thyristor, even connecting through of current starting from a certain voltage (knee voltage), but only if the current at anode and cathode is caused by a impulse current in the gate electrode. In case of the triac this process is also possible with reverse polarity, wherefore it is possible to control both half-waves of alternating currents. By means of gate electrodes, which are connected in a triac and why only one gate electrode is necessary, the point of time can be determined, at which the triac lets the alternating current signal pass. Thereby it is possible to affect the phase, at which the alternating current signal is cut. One speaks also of phase-angle control. Also depending on doping and specific structure knee voltage and maximal current carrying are alterable.
As an additional information: this model is based on the Modelica.Electrical.Analog.Ideal.IdealThyristor.
Type: Resistance (Ω)
Description: Closed triac resistance
Type: Conductance (S)
Description: Opened triac conductance
Type: Voltage (V)
Description: Threshold voltage for positive and negative phase
Type: Resistance (Ω)
Description: Resistance of disturbance elimination
Type: Capacitance (F)
Description: Capacity of disturbance elimination
Ideal triac test circuit