Tuning Phaselead

[Phoenix]

Hello everybody,

I noticed the following thing when tuning phaselead on my DRSSTC: If i tune for the lowest amount of ringing i am getting slightly lower switching speeds (150ns). If I tune for a little bit of ringing i am getting faster switching speeds (60ns). The spikes are small and only 100V high. I am using 1200V IGBTs and my maximal input voltage is 370V DC so the spikes are not a problem.

My question is now should i tune for faster switching speeds or less ringing?

Greetings,
Phoenix

[Hydron]

Slower switching speed isn't such an issue if it's at low current - losses scale with current.

I assume you have a CT (DIY or commercial) to scope the primary current? If so you should be able to look at the relative timing of the switching versus current to make sure it's near the zero crossing.

Getting it perfect is unlikely to be necessary unless you're really pushing the igbts way past their current rating or with spikes near the voltage rating - assuming you're not then I'd err on the side of switching early rather than late as that generally gives lower losses.