Thyristor bridge

Single-phase full-wave thyristor rectifier with two fire inputs.

  • Boolean
  • electrical
  • Modelica Standard Library
  • 6 ports
  • 2 parameters
BlockThyristor bridgeKindthyristorBridgeLibraryConverters

Description

A single-phase fully controlled (two-pulse) bridge of four ideal thyristors. Delaying the fire signals from the AC zero crossings sets the firing angle α and so the mean DC voltage.

fire_p fires the pair that conducts while ac_p is above ac_n (ac_p to dc_p and dc_n to ac_n). fire_n fires the pair for the other half-cycle (ac_n to dc_p and dc_n to ac_p).

Example

Rectifier bridges A diode bridge and a thyristor bridge fired at 90°, each feeding a 10 Ω load from a 10 V sine.

10 V 50 HzGroundDiode bridgeLoad (diodes)v DC (diodes)10 V 50 Hz (thyristors)Ground (thyristors)Thyristor bridgeLoad (thyristors)v DC (thyristors)Fire + at 90°Fire − at 90°
In Gradara, select a Thyristor bridge block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:Voltage sensorGroundResistorAC voltageDiode bridgeBoolean pulse

Ports

Inputs 2

  • f+fire_pBoolean

    Gate command for the positive half-cycle pair (Boolean).

  • f−fire_nBoolean

    Gate command for the negative half-cycle pair (Boolean).

Conserving terminals 4

  • ac+ac_pelectrical

    AC terminal 1.

  • ac−ac_nelectrical

    AC terminal 2.

  • dc+dc_pelectrical

    DC positive terminal.

  • dc−dc_nelectrical

    DC negative terminal.

Parameters

  • Thyristor on resistanceRonThyristor0.00001 Ω

    ≥ 0

    On resistance of each thyristor, in ohms. 0 or more.

  • Thyristor off conductanceGoffThyristor0.00001 S

    ≥ 0

    Off conductance of each thyristor, in siemens. 0 or more.

Equations

Modelica
Continuous DC current, AC amplitude V̂: mean(dc_p.v − dc_n.v) = (2 · V̂ / π) · cos α

Implementation

Modelica Standard Library 4.1.0Modelica.Electrical.PowerConverters.ACDC.ThyristorBridge2Pulse
MSL documentation

Assumptions and limitations

  • Ideal thyristors with the knee voltage fixed at 0 V. No holding current, turn-off time, or commutation overlap unless you add source inductance.
  • Firing logic is not included; you supply both fire signals.

Tips

  • A thyristor latches, so short pulses at the line frequency, delayed by α / (2π · f), are enough. A fire signal held true makes its pair act as diodes.

See also

Select a block in Gradara and press F1 to open its page offline.