Modelling a TVS with PSIM

A uni-direction TVS can be modelled with a zener diode. A bi-directional TVS can be modelled with two zener diodes, connected cathode to cathode

 

From Littlefuse

Breakdown Resistance

We can calculate the resistance of the device by using the breakdown voltage and current to calculate the slope of the IV curve.

Ron = (9.2-7) / 43.5 = 50.5m ohms. I am ignoring the 10mA which is insignificant to the 43.5 peak current.

We should set this as an external resistor.

 

For the bi-diretional setup set the forward voltage to 0.

 

Read the datasheet for the proper Vforward for the uni-directional TVS.

Here are some performance waveforms