Igbt buck/boost/mppt driver  - Page 1
Forum section: electronics / projects

author: Silvally
author_rank: Newbie
timestamp: August 24, 2023, 09:18:15 pm
content: hi I have bought an Igbt boost/buck/mppt driver circuit(using the buck mode) to bring down from 280v to between 108v to 168v 60A (charge a lithium battery for my electric car 40 cells 148v 140Ah)and in the data sheet it says I need a 1mh coil, some suggestions where to find one or how to make one. Have tried using ferrite core but it's hard to get the wire on because I only have small ones, need suggestions for bigger cores. Now I use an iron core from an old toroidal transformer (150mm diameter)and the core gets hot 90c on 12A current and it sounds like an old crt tv 16kHz whine.The frequency it uses is 16kHz (thought iron core could be used up to 20-30kHz).Do i need 1mh or can i use smaller value. Will only use 300v and below and up to 100A.link to the driver link:https://www.aliexpress.com/item/1005004915626819.html?spm=a2g0o.productlist.main.21.488b6f73X0zWsS&algo_pvid=e99e96a9-4bbb-4590-959f-426cfede9dc1&algo_exp_id=e99e96a9-4bbb-4590-959f-426cfede9dc1-10&pdp_npi=4%40dis%21SEK%21774.13%21735.45%21%21%2169.05%21%21%40211b88ec16929089953932181ecf1d%2112000031005619398%21sea%21SE%210%21A&curPageLogUid=qHzFlygSZUdy

author: moffy
author_rank: Super Contributor
timestamp: August 25, 2023, 12:54:11 am
content: The inductor is probably going to cost a lot more than everything else, 1mH/100A is a very significant inductor. A way to reduce the inductor size is to increase the switching frequency but that would require significant design modifications.

author: Silvally
author_rank: Newbie
timestamp: August 25, 2023, 01:25:31 pm
content: Can i use the ferrite cores from woofers, they are 200 mm outer diameter.Just need to demagnetize them.

author: moffy
author_rank: Super Contributor
timestamp: August 25, 2023, 10:36:12 pm
content: A 1mH/100A@16kHz inductor will take some significant design to implement reasonably well. The winding copper resistive losses, core losses, saturation and COOLING (excuse the caps but that is really important) will all need to be properly designed e.g. just 0.1R resistive losses at 100A gives 1kW dissipation! Even purchasing such an inductor would require research. I had a 5mH/200A inductor made for me, designed by my then boss, it was an air cored pancake construction, made of I think five windings separated by wooden slats for cooling and the copper weighed over 100kgs and about 1m in diameter. The windings were flat copper bar covered in kapton tape, beautiful design and construction.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 25, 2023, 11:28:51 pm
content: Does this thing even come with instructions? There's not nearly enough data on the sale page to even wire it up, let alone how to use it. What made you buy it?!Tim

author: Silvally
author_rank: Newbie
timestamp: August 26, 2023, 04:26:07 pm
content: I bought it because I needed a variable current source dc-dc hi power,and I have many igbt lying around from frequency converters and other electronics. (the igbt i use now is 2MBI100SC-120)How to connect it is in the first picture and how to connect igbt is further down in another picture.Not much in the way of instructions, but enough to get it working,and need to move some smd resistors for different mppt/buck/boost functions

author: Silvally
author_rank: Newbie
timestamp: August 26, 2023, 04:37:00 pm
content: Doesn't it need more copper for a coil without an iron/ferrite core?What did you use a 5mh coil for?Does the magnetic field matter if it is left in the ferrite core from the woofer thought of trying to wind one. And if it dose any good tips on how to demagnetize it, tried heating a ferrite core to 480C but it cracked.

author: moffy
author_rank: Super Contributor
timestamp: August 27, 2023, 12:14:37 am
content: Quote from: Silvally on August 26, 2023, 04:37:00 pmYes it requires larger turns and more copper, you use area plus the mutual coupling between the coils, but it is an illustration about how non trivial a 1mH/100A@16kHz coil will be. If you aim for just 0.01R winding resistance you will still be dissipating 100W and your copper will have a significant cross section. You will also need to work out the max temperature rise and ensure that the insulation is suitable and you haven't even considered the core yet, with its losses, saturation, temperature rise, air gapping etc. And you are attempting to use an undocumented core, the speakers, which sounds like a ferrite magnet which would be a magnetically hard material and really unsuitable?Regarding what the inductor was used for, it was a smoothing device between a 3 phase SCR 1500V/130A supply and some large DC locomotive motors of the order of 1MW for testing purposes. Because it was air cored of course the magnetic field was unconstrained, and during the commissioning a phase latched in and the full phase voltage was applied with currents probably around 600A developed, before the breakers tripped. We went into the room where the power devices were stored and found the inductor had moved 1.5m and was hard up against the core of the power transformer. It managed to break a couple of the wooden slats in the process. I was glad it was air cored as it didn't saturate and limited the fault currents. We chose a more remote part of the room to place the inductor and bolted it down afterwards.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 27, 2023, 02:31:27 am
content: Quote from: Silvally on August 26, 2023, 04:37:00 pmOh, I finally parsed this-- you have the ferritemagnetfrom a woofer (large speaker), andyou thought abouttrying to make an inductor with it.This project has all the red flags:- Lack of information (poorly documented system, unfamiliarity with SMPS component selection/design)- Beginner project / massive power level- Looking for impossibly cheap solutions without knowing whether they could even workI may be severely misinterpreting the poor grammar here -- English sucks enough for native speakers as it is -- but it happens that it conveys a message of carelessness.Case in point, a ferrite toroid is the wrong thing. Ungapped ferrite saturates at low currents -- maybe ten amperes in the size you require.A magnet is even worse: it has maximum hysteresis loss and no permeability. It's completely the wrong kind of ferrite to use here.The most likely material is powdered iron, which you will still spend a few hundred bucks on for something of this size starting from new commercial parts.It paints a picture of, you've purchased this product, and some salvaged parts, in the hopes of throwing together a cheap system, and now you've hit a snag because you didn't think far enough ahead to even know whatbasic components a buck converter requires(i.e. input cap, choke, output cap), and have neglected to budget for it in any way shape or form, purely assuming that you'll stumble into a solution along the way, as you've seemed to with every other part so far.Without seeing any build photos and schematics, I will go out on a limb and guess that this will be a fine way to end up electrocuting yourself, or burning down the house and potentially the neighbors too. At the very least, significant property damage is a possibility, from the rather large solar panels (or other sources), or the EV [battery?], to any surrounding buildings, or loss of life, and, I don't know maybe negligence charges related to those or something. No insurance company will cover such a hack job, you're on the hook for any and all destruction resulting from this thing.I strongly urge other posters here to heed the same warning, and provide no further assistance until a safe assessment can be made.Tim

author: Silvally
author_rank: Newbie
timestamp: August 27, 2023, 10:34:47 pm
content: I work as an electrician and have done so for 8 years, installing solar panels EV chargers large motor inverters from 0.1 kW to 6 MW and fixing smaller electronics, dry capacitors in some smps, varistors from over voltage (mostly when the neutralpoint comes loose) and other stuff.The nearest neighbor is 2 km and the nearest building is 50m away I live on a farm so I'm not afraid that something will catch fire.I have capacitors on input and output. When I bought the circuit I didn't think about how big the coil would be that's why I'm asking here, the ferrite core from a bass speaker was a friend's idea. Was just curious if it would work.I have been looking for a powerful dc-dc converter for a long time. Hard to find something that works,Want something that has the same functions as the smaller ones0-200vdc in 0-200vdc 0-3A out, but instead of 0-3A I want 0-100AWhat usually costs is the power electronics the drive circuit not that much so i usually buy the drive circuit and then i build the rest.Have a whole moving box full of igbt's, it weighs like 50 kg.I have built a converter that converts 48vdc to 220v 3.5 kva ac sine wave bought the driver circuit from aliexpress and built the rest myself and all for under 1200 SEK. It can power a welder and start and run 2 kw sodium arc lights and power water pumps on 2.5 kw pumps. and it still works 4 years later, 24/7 on timeI have bought professional (as they call it) converters here in Sweden but they haven't worked, they say they can handle 3kw continuously but can't even start a 1kw water pump and when you have to use the sodium lamp, the magic smoke comes from them and they cost 8000-10000 SEKRight now I have a 3-phase isolation transformer 8kVA or 10 kVA (the sticker is gone)which takes 3x400vac to 3x200vac and then rectifies it to 290vdc and then it goes to a capacitor bank 4x 500v capacitors of 2200µf. the output side has 2x 500v 2200µf capacitors. I know that I will not be able to extract more than 50A at 160v with this transformer to charge the electric car. Right now I can only take out 12A because the iron core gets too hot.looks like I need to find some other buck driver circuit, any ideas?

author: moffy
author_rank: Super Contributor
timestamp: August 28, 2023, 01:09:18 am
content: I would suggest that you start a new topic and outline in some detail your objective and invite suggestions. e.g. I have an 8kVa 3phase transformer .... and I would like a 0-200V dc at up to 100A power supply what do you suggest?I have just abbreviated the example but I am sure you understand. First comment you will get is that 200*100 = 20kW exceeds your transformer rating.

author: Silvally
author_rank: Newbie
timestamp: August 28, 2023, 08:41:27 am
content: I know I can't get more out of the buck than I put into it. right now I have a 3 phase transformer to drive it to charge electric car 30A is enough here then maybe I use solar panels 48vdc 30 Aand only need 12V 20A for other project. and later maybe I'll test a dc motor at 20kw and do I need to regulate the current, or for something else.What I need is a module that can take different voltages in and give different voltages out with amp regulationlike a buck. Haven't found anything else.0-350v in 0-300v out(I know I can't get more volts out than I put in)and 0-100A outThis driver circuit can handle up to 999v (they say lol) so 350v shouldn't be a problemand I have enough power to run it on full power 350v 100A (has a diesel generator of 0.85MVA).I'll look into making a pancake coil of 1mh 100A looks like the only way out

author: Marco
author_rank: Super Contributor
timestamp: August 28, 2023, 09:00:51 am
content: 25A 1mH are easily available, but looking at the price (about 50$ on aliexpress) 100A is going to be costly.

author: Silvally
author_rank: Newbie
timestamp: August 28, 2023, 09:35:21 am
content: Link

author: Marco
author_rank: Super Contributor
timestamp: August 28, 2023, 09:54:18 am
content: https://www.google.com/search?q=5kw%20sendust%20inductorThey just stack a bunch of sendust toroids and then wind a bunch of parallel windings of copper clad wire (I assume it's clad any way).