Ideal switch

Ideal bidirectional power switch. Gate above 0.5 closes the switch; zero on-resistance and zero off-conductance.

  • signal
  • electrical
  • Gradara equations
  • 3 ports
BlockIdeal switchKindidealSwitchLibraryElectrical

Description

An ideal bidirectional switch controlled by a real-valued gate signal. A gate above 0.5 closes it into a short circuit; otherwise it is an open circuit.

Example

Switches and a breaker An ideal switch, closing and opening switches, a two-way switch, and a breaker that opens an inductive circuit.

10 V Ai ALoad AIdeal switchGate 5 HzGround A10 V Bi BClosing switchClose at 0.1 sLoad BGround B10 V Ci COpening switchOpen at 0.1 sLoad CGround CL 10 mH10 V Di DBreakerTrip at 0.1 sLoad DGround D10 V Ei ETwo-way switchChange over at 0.1 sLoad 10 ΩLoad 20 ΩGround E
In Gradara, select a Ideal switch block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:DC voltageCurrent sensorGroundPulseResistorInductorSwitch (Boolean)Opening switchChangeover switchBreaker (with arc)Boolean step

Ports

Inputs 1

  • ggatesignal

    Gate signal. Closed while gate > 0.5, open otherwise; 0/1 PWM signals work directly.

Conserving terminals 2

  • +pelectrical

    Positive pin. Current into p is counted as positive.

  • −nelectrical

    Negative pin.

Equations

Modelica
p.i + n.i = 0
closed (gate > 0.5): p.v = n.v
open: p.i = 0

Assumptions and limitations

  • Zero on-resistance and zero off-conductance (MSL IdealClosingSwitch with Ron = 0 and Goff = 0). No losses, dead time, or switching transients.
  • Current flows in either direction when closed.

Tips

  • Opening it in series with an inductor, or closing it across a charged capacitor or a voltage source, has no finite solution. Provide a freewheeling diode or a small resistance.

Used in

These larger examples use it too. Open them from Examples in the app.

  • Buck converter · Ideal switches

See also

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