Recent content by zombiess

What is the thought process of those 1uF ceramic caps on the DC bus? Notice any difference with them vs without them? I tried something similar, but with polypropylene caps as large ceramics are prone to cracking under thermal stress + suffer dielectric effect. I don't recall seeing any...

My solution for a high current, low cost diode for use in an clamping RCD snubber was to use the body diode in a MOSFET. I've seen decent results with the body diodes current sharing when paralleling as well, when I monitoring current flow through each discrete device leg. I haven't fully...

The IR2110 is no where near suitable for your application. The zener is chosen based on the RDSon of the devices you are switching. The desat pin outputs 7.2V @ 250uA, so your choice of zener can get interesting as most don't supply ratings for < 1mA. What I've done is buy an assortment of...

I thought someone had posted on here about these motors failing around 10k RPM. Maybe it was Methods? This thread has some info https://endless-sphere.com/forums/viewtopic.php?f=30&t=81009

I'd encourage you to practice more isolation techniques. They can really reduce noise by minimizing coupling. I've found that booster stages haven't been needed when switching at normal speeds, even with multiple parallel devices. They may be needed for some devices, so it's a good idea to do...

What is does the double pulse test look like when you do it at low current, like 10-30A or at lower DC bus? I've found some device I've tested look like your scope shots at high current, however at lower currents and voltages there was oscillation. I never got to root cause, just wondering if...

Turn on the device under test until the desired test current is reached. Turn off the device under test and allow any oscillation to settle, 10-50us is usually plenty Turn on the device under test for a predetermined amount of time, then back off. This second pulse demonstrates how the device...

This is an accurate statement. Power electronics is not an easy field of study. Have you tried to slow down the switching even more to see if it cleans up? Maybe try adding an oversized G-S cap, say 47nF. Sometimes with enough it will dampen the ringing. Have you figured out the layout...

I don't switch fast or slow, I only switch as fast as is needed after examining the entire system. I'm advocating for a less aggressive approach to increase probability of success and faster, usable results. It's incredibly rare to get it correct on the first pass. Some of the things I design...

Would you both share the benefits you see in switching really fast? What does switching in 50ns vs 500ns really mean to your target application? Are you targeting continuous use (years of non stop running) or something more along the lines of use in a personal electric vehicle? How does 60W...

I have some questions: What percentage do switching losses make up of your total losses? How slow can you switch the device and still obtain acceptable results? What is the minimum switching frequency you can utilize to drive your load? How much DC Link ripple current do you need to drive your...

I wonder how much safety margin is available at 98% duty cycle. What is the switching frequency set to? The time to switch on / off can vary quite a bit under real world conditions cycle to cycle and change at different operating temperatures and vary between parts. It's pretty easy to get...

If you want to experiment with high current, I'd strongly recommend switching to a gate driver design with safety features such as a miller clamp. There are some which have both a high and low side driver, but there are more options in single driver per package design. It is difficult to...

Mihai_F, do you have a schematic for your design? Read this before deciding to switch devices as fast as possible. Choosing device switching time is about balance. https://toshiba-semicon-storage.com/info/docget.jsp?did=59464

I'm curious as to what benefit you are getting adding decoupling capacitors. I've found that with a good layout that my DC Link cap is enough and no additional capacitance is required unless I add a RC/RCD snubber, but then the application is different. I've also found adding capacitance down...