Effect of Adding an External Inductor in a DC Inverter Welder’s Output Circuit

[Denny55]

Hi all,
I’m working on modifying a DC inverter welder and I’m exploring the impact of inserting an extra external inductor in the output side (after the main H-bridge). I’d appreciate feedback from anyone who’s experimented with similar setups.

Here are my current details and questions:

System details:

• Inverter welder rated ~150 A DC output
• Switching frequency around 50 kHz
• Built-in choke/inductor already included

My experiment idea:
Add an external toroidal inductor (iron-powder core) rated for ~200 A continuously, value ~30 µH.

Key questions:

1. Would the extra inductance improve arc stability and reduce spatter, or could it slow down current response and cause poor arc strike?
2. What inductance value range have you found effective (for 100–200 A welders) without negative side-effects?
3. Core type considerations — iron-powder vs ferrite vs laminated steel for high current?
4. How does this affect IGBT switching parameters or inverter control (do we need to adjust dead-time or slope)?
5. Are there thermal or saturation issues I should monitor when adding external inductors in welding applications?

Thanks in advance for any suggestions, measurement results, or design tips you can share!

 

[Delta Prime]

Make and model of your DC inverter welder you wish to modify please.