Thyristor with Reverse Recovery

Purpose

Dynamic thyristor (SCR) model with reverse recovery

Library

Electrical / Power Semiconductors

Description

This component is a behavioral model of a thyristor which reproduces the effect of reverse recovery. The effect can be observed when a forward biased thyristor is rapidly turned off. It takes some time until the excess charge stored in the thyristor during conduction is removed. During this time the thyristor represents a short circuit instead of an open circuit, and a negative current can flow through the thyristor. The thyristor finally turns off when the charge is swept out by the reverse current and lost by internal recombination. The same effect is modeled in the Diode with Reverse Recovery and described there in detail.

Note

Due to the small time-constant introduced by the turn-off transient a stiff solver is recommended for this device model.
If multiple thyristors are connected in series, the off-resistance may not be infinite.

Parameters

Forward voltage: Additional dc voltage \(V_{\mathrm{f}}\) in volts \((\mathrm{V})\) between anode and cathode when the thyristor is conducting. The default is 0.
On-resistance: The resistance \(R_{\mathrm{on}}\) of the conducting device, in ohms \((\Omega)\). The default is 0.
Off-resistance: The resistance \(R_{\mathrm{off}}\) of the blocking device, in ohms \((\Omega)\). The default is 1e6. This parameter may be set to inf unless multiple thyristors are connected in series.
Continuous forward current: The continuous forward current \(I_{\mathrm{f0}}\) in amperes \((\mathrm{A})\) under test conditions.
Current slope at turn-off: The turn-off current slope \(dI_{\mathrm{r}}/dt\) in \((\frac{\mathrm{A}}{\mathrm{s}})\) under test conditions.
Reverse recovery time: The turn-off time \(t_{\mathrm{rr}}\) in seconds \((\mathrm{s})\) under test conditions.
Peak recovery current: The absolute peak value of the reverse current \(I_{\mathrm{rrm}}\) in amperes \((\mathrm{A})\) under test conditions.
Reverse recovery charge: The reverse recovery charge \(Q_{\mathrm{rr}}\) in coulombs \((\mathrm{C})\) under test conditions. If both \(t_{\mathrm{rr}}\) and \(I_{\mathrm{rrm}}\) are specified, this parameter is ignored.
Lrr: This inductance acts as a probe measuring the \(di/dt\). It should be set to a very small value, in henries \((\mathrm{H})\). The default is 10e-10.

Probe Signals

Thyristor voltage: The voltage measured between anode and cathode.
Thyristor current: The current through the thyristor flowing from anode to cathode.
Thyristor conductivity: Conduction state of the internal switch. The signal outputs \(0\) when the thyristor is blocking, and \(1\) when it is conducting.

References

A. Courtay, “MAST power diode and thyristor models including automatic parameter extraction”, SABER User Group Meeting Brighton, UK, Sept. 1995.