Thermal network transformation: Foster fourth order to Cauer first order?

Hello, in the symscape power systems example "Loss Calculation in a Three-Phase 3-Level Inverter" there's a block of a half-bridge IGBT with loss calculation. I wanted to know how you calculated the junction to case thermal resistance and the junction thermal capacitance for this block, since the manufacturer’s datasheet only gives the R and C parameters of a fourth order Foster network, and from what I see in the example the junction to case thermal resistance and the junction thermal capacitance correspond to a first order Cauer representation.

Answer 1

[Carlos Rueda]

A method to find the equivalent Cauer network from the fourth-order Foster network is shown in Appendix A of book "Transient Electro-Thermal Modeling of Bipolar Power Semiconductor Devices" by Gachovska et al.

Answer 2

[Joel Van Sickel]

Moving Carlos Rueda's answer down here to clean up which questions are flagged as unanswered.

Carlos Rueda on 19 Dec 2019

A method to find the equivalent Cauer network from the fourth-order Foster network is shown in Appendix A of book "Transient Electro-Thermal Modeling of Bipolar Power Semiconductor Devices" by Gachovska et al.