PWM for HV switching capabilities - Page 1
Forum section: electronics / projects

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 02:13:49 pm
content: Hi,Does anyone know something similar to the below device that is available for purchase for relatively cheap?https://www.rmcybernetics.com/shop/cyber-circuits/pulse-generators/pulse-modulator-ocxi

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 03:43:58 pm
content: Bumping for attention

author: Marco
author_rank: Super Contributor
timestamp: January 05, 2024, 03:49:52 pm
content: It's already cheap. It's not something 1000s of people want like an electronic load, how much cheaper do you expect that to be made? If it fits your requirement be overjoyed they save you a ton of work for so little money.PS. that said, maybethissuits your purpose ... that's far cheaper than I expected it to be for something with two high voltage GAN FETs.

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 03:53:44 pm
content: I'm not wanting it to be cheaper. I want to see if there are alternatives since it's on backorder ...

author: Marco
author_rank: Super Contributor
timestamp: January 05, 2024, 04:21:35 pm
content: Oops, that other board is out of stock too.GAN transistor evaluation boards are probably your best bet though.

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 07:00:58 pm
content: Can you provide an example and how exactly to use it?

author: inse
author_rank: Super Contributor
timestamp: January 05, 2024, 07:28:09 pm
content: You know, boy, hard switching at these frequencies and voltages is not a beginner’s project.I have been in a project for a PFC stage for 22kW.Here 400V are being switched with _only_ 100kHz and there have been issues one couldn’t imagine.Violent explosions were common issues.What exactly do you want to build, would you share some details with us?And as already asked before: do you have the equipment to debug your circuit?

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 07:34:52 pm
content: I understand this is not a beginner's project. I am building a novel prototype device that responds best to unipolar voltage pulses. I want to play with the amplitude and frequency of the input to find the sweet spot. Yes, you can assume I have most of the relevant devices necessary for debugging.

author: inse
author_rank: Super Contributor
timestamp: January 05, 2024, 08:31:54 pm
content: Maybe it has become a little more clear now.So you need more or less rectangular pulses with variable frequency and voltage, not HV AC?In the company we have a EMC department which does all the compliance testing.They have generators for all kinds of pulse tests, maybe your requirements are more into this direction?

author: DejanC
author_rank: Regular Contributor
timestamp: January 05, 2024, 08:37:12 pm
content: Yes, need HV unipolar pulses of variable frequency

author: Marco
author_rank: Super Contributor
timestamp: January 06, 2024, 07:52:25 pm
content: Quote from: DejanC on January 05, 2024, 07:00:58 pmThispaperhas the logic needed to change a simple square wave drive to one which introduces dead time to prevent half bridge shoot through. If you combine that with a GAN half bridge with fast half bridge driver likethis, a signal generator and a high voltage DC supply, you can generate your high voltage square wave output.Alternatively try to find a dealer to sell you something like aPVM-1001. Digikey/mouser used to stock it, but no more. Still it seems under 1000$, so not too expensive.

author: inse
author_rank: Super Contributor
timestamp: January 06, 2024, 10:34:11 pm
content: The abstract of the paper alone scares the shit out of me

author: Marco
author_rank: Super Contributor
timestamp: January 06, 2024, 10:58:17 pm
content: Actually the SI8230 used on the half bridge demo board seems to have dead time control, so you won't need any extra logic if you figure out how to use that except an inverted version of the squarewave.So all you really need is that half bridge demo board, a signal generator and a high voltage power supply. Plus a plastic project box and some some shielded connectors so you don't electrocute yourself.