Bug Simulating Thermal Losses for a Rectifier based on Foster Model

I am trying to simulate the thermal model for a rectifier like the following example: https://www.mathworks.com/help/physmod/sps/ug/simulating-thermal-effects.html#bvdojyf.

However, I am not getting the same results as the example shows for all diodes (last picture from the link).

The problem occurs only for Diode 3 and 6 as shown in the image below. The picture shows a large temperature at the beginning of the simulation.

If the graph just shows the Diodes 1, 2, 4 and 5, the results are similar to the example ones.

My first thought is that the problem is a bug from Matlab, but since I am not certain about this I decided to ask the community. So, what do you think of this odd behaviour?

Simulink Model:

Foster Model (Subsystem):

Answer 1

[Joel Van Sickel]

Hello,

the issue here is that the system is calculating less than ideal initial conditions. The foster model's have the "start from steady state" option selected. Given this is an AC system, the steady state tool is not correctly identifying the appropriate starting condition for temperature. If you uncheck this box, you will get somewhat better initial conditions, and you can take it one step further by specifying your initial conditions for the starting temperature of these devices.

Regards,

Joel