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Buck chopper with thermal model

Download Simba model

This example shows a basic DC-DC buck chopper with thermal descriptions for the igbt and the diode and a thermal model of an heatsink. Here are the following characteristics:

  • an input voltage of 600 V,
  • an output LC filter with L = 1.2 mH and C = 100 µF,
  • a resistive load of R = 15 mΩ,
  • a switching frequency of 10 kHz.

Electrical Model

The schematic below shows the electrical model considered.


Thermal model

The igbt and the diodes are associated to thermal descriptions which have been imported from thermal library files (.xml). These thermal descriptions are available via the Test Bench tab in the Thermal Data menu. They contain loss data (conduction voltage drop, switching energies) but also the thermal impedance of the powerswitch as shown below.

loss data

thermal impedance


The model is simulated with the option Stop at Steady State enabled to ensure the steady state is reached.

Loss data of powerswitches such as instantaneous switching losses or average losses on a period defined by the user in the powerswitch parameters.

The figure below shows the instantaneous switching losses and the inductor current:

switching energy loss

Junction temperatures of powerswitches or the thermal capacitor temperature that models the heatsink inertia are also available as shown below: