# Soft switching implementation in a DAB converter

**URL:** <https://forum.plexim.com/t/soft-switching-implementation-in-a-dab-converter/2666>\
**Category:** PLECS\
**Tags:** zvs, soft-switching, dab\
**Created:** [October 31, 2025, 8:39am UTC](https://forum.plexim.com/t/soft-switching-implementation-in-a-dab-converter/2666 "2025-10-31T08:39:00Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![Munadir\_Ahmed](https://dub1.discourse-cdn.com/flex006/user_avatar/forum.plexim.com/munadir_ahmed/32/1540_2.png) [@Munadir\_Ahmed](https://forum.plexim.com/u/Munadir_Ahmed)\
**Post date:** [November 4, 2025, 6:44pm UTC](https://forum.plexim.com/t/soft-switching-implementation-in-a-dab-converter/2666/7 "2025-11-04T18:44:15Z")

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Hi Nishan, maybe a workflow like the following might be an option for you:

- using a configurable subsystem, setup a configuration where you use parasitic capacitances and no thermal losses to capture if your system achieves ZVS or not across a few operating conditions. you could use this model to validate if your analytical model matches simulation results.
- if you also want thermal simulation then you could have a configuration that uses ideal switches + thermal loss data with a scaling factor (based on your previous test) to capture the thermal impacts of ZVS.

Something to consider to make your life easier:

 ![image](https://europe1.discourse-cdn.com/flex006/uploads/plecs/original/2X/f/fd4148a20f0ea8bbf9d4844404d4152414f02d6a.png)

If you decided to start experimenting with configurable subsystems you might benefit from the usage of model reference. See section 7 of [this document](https://www.plexim.com/sites/default/files/tutorials_categorized/plecs/component_libraries.pdf). This way you don’t have to maintain 4 separate modules here but only have to make changes to 1 module as you start tinkering. E.g. IGBT/diode subsystem being driven by SP1 could be the reference module and all other submodules could use model references.

Finally, I don’t have a lot of experience with DAB converters but having worked extensively with flyback converters I have found that the Coss is not the only contributor to the parasitic capacitance that needs to be discharged for ZVS. It is a good starting point but just wanted to make you aware as you might see a different result in the lab. For the flyback, the approach I took was:

- measure the magnetizing inductance of the flyback converter with an LCR meter
- operate the HW flyback converter deep in DCM and measure the primary switch drain to source voltage ringing frequency in DCM
- back calculate the node capacitance based on the above measurements → effectively I lumped all the parasitics capacitances like your Coss, transformer winding capacitances, etc

I then utilized PLECS to determine what the system would need to achieve ZVS operation for an active clamp flyback (e.g. what drive duration for the clamp switch, dead-time between clamp switch and main switch, etc).

Hope this helps!

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