finding equivalent Power mosfet in HF tube welding machine

Thread Starter

Marlon Cevallos

Joined Oct 12, 2017
Hi everyone,

I'm new in this forum, my english is a bit bad but I'll try to explain my problem.

I dont have much experience in power electronics and
I have this mosfet: ,

The thing is, this mosfet is obsolete right know and I have problems getting replacements, so I need a easy to find equivalent mosfet,

Mosfet came originally in a HF tube welding machine: some specs

First stage, 3 phase six pulse rectifier 380Vac
Final stage, 1 phase inverter, Output 500Vrms, switching frecuency 400kHz max.
The inverter stage have 6 blocks with mosfets-diodes connected back to back (see attached photo) they work in two stages wih two diferent firing pulses (see attached photo). Each block have 16 mosfets-diodes in parallel

Parallel diode is

This are the best matches I could find:

I'm fighting with switching times and Id / Vds characteristics, I cant find equivalent mosfet with good ones as original.

I'm studying this problem but I want to hear opinions from more experienced people .

Thanks for your help
firing pulses
firing pulses.jpg
output voltage waveform
output voltage.jpg