Diode Power losses in Simscape Electrical

Hi,

following my previous question on Power losses in Simscape Electrical, the only way to calculate the power losses in a three phase inverter is to split IGBT module on IGBT and Diode and calculate losses for each component separately. And then for each component use separate thermal element as IGBT and Diode have different junction to case resistance. Only at case to heatsink losses ca be combined. Please confirm is this assumption is correct!

Now, I have the question what element to use for Diode? There is no explanation on how the power losses are calculated for Diode. Theory says there are conduction and switching losses. For conduction losses I see entry points for If and Vf, but for switching losses I cannot see where to enter Err, i.e. switching energy. How accurate is the final result? In IGBT module diode switching (reverse recovery) losses cannot be ignored and they are even higher that conduction losses.

Kind regards

Answer 1

[David John]

Reverse recovery loss can now be tabulated for a diode using the Simscape Electrical diode block: Piecewise or exponential diode - MATLAB (mathworks.com). See Reverse recovery loss table, Erec(Tj, If)

[yuji Ito]

Thanks a lot!

[David John]

You're welcome. If you're happy with this answer, please feel free to "accept" it so that the community can see that this question is no longer open.

Many thanks,

David

Answer 2

[David John]

For diode losses, we always include conduction losses. For switching losses, you need to use a model where "Charge dynamics" on the "Capacitance" tab are enabled. This will reveal some additional parameters to characterize the switching dynamics of the diode. Once these parameters are set, you can look at the power_dissipated variable inside the diode (either using the simlog or the MATLAB function ee_getPowerLossSummary). The standard "Diode" block includes this option.

We do not have an option for providing Err directly in tabulated form at this time, so dynamic simulations are required.

Answer 3

[yuji Ito]

Will this issue be resolved in FY2022?