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  1. Z

    20Kw motor and 300A ESC (ultralight aircraft propulsion system)

    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...
  2. Z

    Importance of RCD Diode !

    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...
  3. Z

    20Kw motor and 300A ESC (ultralight aircraft propulsion system)

    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...
  4. Z

    Zero motor 75-7 markings, red sticker, DANGER?

    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
  5. Z

    20Kw motor and 300A ESC (ultralight aircraft propulsion system)

    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...
  6. Z

    20Kw motor and 300A ESC (ultralight aircraft propulsion system)

    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...
  7. Z

    20Kw motor and 300A ESC (ultralight aircraft propulsion system)

    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...
  8. Z

    A Small 6 fet Vesc 6 Design

    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...
  9. Z

    Rough draft of a 6FET power stage intended to be part of a larger controller

    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...
  10. Z

    Rough draft of a 6FET power stage intended to be part of a larger controller

    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...
  11. Z

    Rough draft of a 6FET power stage intended to be part of a larger controller

    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...
  12. Z

    FLIPSKY new 20s 100A tiny controller (vesc based)

    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...
  13. Z

    Rough draft of a 6FET power stage intended to be part of a larger controller

    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...
  14. Z

    300A bldc esc, mosfets ringing, help

    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
  15. Z

    300A bldc esc, mosfets ringing, help

    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...
  16. Z

    300A bldc esc, mosfets ringing, help

    Polypropylene caps are often the best choice for DC link for a high reliability design. They provide high current capability in a volume smaller than most electrolytic solutions with a longer working life. They are also used for decoupling and I generally would use them vs a ceramic capacitor...
  17. Z

    HESC V1 150v 600Amp VESC based motor controller

    Where are the DC Link caps? Where does the power feed into the controller? How are you removing heat? The power feed order should be: Battery -> DC Link Cap -> DC bus
  18. Z

    300A bldc esc, mosfets ringing, help

    Sorry if this comes off a bit harsh, but you are venturing into aerospace engineering in what appears to be an unprepared manner. The following isn't meant to be negative, it's meant to make you think. Just my personal opinion, but I think flying with the controller setup pictured is bad risk...
  19. Z

    VESC based +200A powerstage with 200V MOSFETs (videos of it in action)

    The waters are often deeper than they first appear. Power electronics work can be a very humbling experience. My noise issue is not related to layout, but good guess. It's actually related to the inductors capacitance. I learned A LOT on this one project. My layout decisions are related to...
  20. Z

    1S100P boost controller

    Inductor is in a different location in a boost or buck topology. I wonder if CPU SMPS's utilize soft switching to reduce forward/reverse diode conduction losses? A bigger issue I see is the input to output ratio. Using a boost converter is not a bad idea, but it needs to be appropriately...
  21. Z

    VESC based +200A powerstage with 200V MOSFETs (videos of it in action)

    I've considered selling them as a stand alone product. $22ea is the total manufacturing cost for me if I have them assembled,with wires soldered on, but no enclosure. If you need a low cost solution, you can use an isolated AC-DC converter and just feed it DC directly from the pack, many will...
  22. Z

    VESC based +200A powerstage with 200V MOSFETs (videos of it in action)

    I've found SMPS design more challenging than power stage design, power stages are big, dumb and pretty robust. There was a lot of failure involved in developing this SMPS, however I've seen on forums that's not an uncommon experience. Plenty of failed controller chips as they do not tolerate...
  23. Z

    VESC based +200A powerstage with 200V MOSFETs (videos of it in action)

    Yes, I have made some progress on design, but not in production. I have an updated design with manufacturing in mind if I ever get there. The new power stage pulls from what I learned from this one and has 18-24 TO-247's, improves thermal performance and takes up a smaller volume. I still...
  24. Z

    Non-silicon and/or soft-switched controller topologies?

    A phase shunt + comparator could work, but I don't know how sensitive GaN devices are to overload. Si devices handle it quite well, but from what I've read and heard, GaN design takes more finess. Unfortunately, I don't have experience. Down side with phase shunts is power dissipation, but in...
  25. Z

    Non-silicon and/or soft-switched controller topologies?

    A gate drive which is able to detect it and take action. But I've never worked with GaN so I'm unfamiliar with gate drivers used with them. Something on the DC bus would probably be too slow to take action, generally you need to shut down as quickly within 5us (sometimes a two level off if...
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