Search found 30 matches

by Mihai_F
Oct 25 2021 4:56pm
Forum: Motor Technology
Topic: 20Kw motor and 300A ESC (ultralight aircraft propulsion system)
Replies: 2
Views: 115

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

Hy guys, i will move here the discussion about my 20Kw motor and 300A esc. This is been a project for my past 6 years, it's been a huge learning curve. Before i started this project my experience with electronics was with power audio circuits, analog stuff, and nothing digital. I will start first wi...
by Mihai_F
Oct 25 2021 1:25am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Thanks guys for appreciation of my motor, i will make a separate topic to show you a bit of the past 6 years of me learning how to make an BLDC ESC and the motor, so i don't hijack mxlemming topic 😬, and hopefully it won't take me that much time to get the ESC back working. Nice rotor by the way, i ...
by Mihai_F
Oct 21 2021 3:12am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Got a pic? I’ve been using cut strips of nylon fishing line as spacers and it’s far from accurate. how do you all glue your magnets? yep, it centers on the shaft, and the magnets are inserted in the slots and then outward to the ring IMG_3460.JPG the plastic one is the same magnets were glued with ...
by Mihai_F
Oct 20 2021 10:06am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

Well in that trace, the motor was running WOT at 3000rpm, at that speed commutation time is 166us, pwm is not present since duty cycle is 100%, hence wot, my scope was set for 64 captures and every now and then, completely random about 10 to 14 shots out of 64 but not in a order, they are random, i ...
by Mihai_F
Oct 20 2021 8:47am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Nice job, looking good for testing. About magnets precise placement, (within +/- 0.05mm) the larger the diameter of the rotor, the greater the electrical degres error you will have if magnets have different distaces between them. On my rotor i made a wooden slotted tool for precise magnets placement...
by Mihai_F
Oct 20 2021 8:18am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

However, you will have to take care that when you change between the hall states and thus high being pwm'd and low clamping that you insert dead time of sorts..... ... Is this one in 4 the one at the end of the hall sequence? I did not fully understand that “is this the on in 4... “ And can you ela...
by Mihai_F
Oct 20 2021 6:37am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

Have you got a gate trace to go with this? Parasitic turn on should be visible from the gate signals. I had something similar to this when I was writing my code for BLDC... It was the result of the timing between commutation and pwm and i got partial pulses occasionally. How much dead time are you ...
by Mihai_F
Oct 19 2021 4:23pm
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

this is on high side fet-s, but not all the time, in 64 captures about 1/4 of them every now and then are like this, the rest of them are without that pulse after turnoff, could it be self turn on or what is that? i read a few suggested papers (parasitic turn on, dv/dt, ect.) and i suspect gate resi...
by Mihai_F
Oct 18 2021 4:10pm
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 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 Well i had 2 attempts at making a complete schematic and to this day i di...
by Mihai_F
Oct 18 2021 10:46am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

I did very careful measurements of lm5017 and posted the results in peters' thread for comparison. There is virtually no ringing on it atall. You've changed the gate resistor value as well. You haven't just hit a sweet spot in the switching speed have you? Generally at higher currents your snubbers...
by Mihai_F
Oct 18 2021 6:47am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

This last measurement was made directly on FET legs close to case with tip of the probe and the short coiled gnd aroud the tip, that is not easy to make and grate care must be taken not to short circuit FET legs to the busbars or to themselves, that will be even more difficult in the open air while ...
by Mihai_F
Oct 18 2021 5:12am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

I tried this morning with snubbers (4.7n+5r) on low side fet-s and 47R gate resistor, things improved big time at 10A load (compared with the first measurement in the post with no snubbers), now in the next days i'l go out put the prop on and give it load and see how it turns up, hopefully not :flam...
by Mihai_F
Oct 16 2021 6:35am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

The v1.2 had about 500ns turn off and this on the output at 75V and 130 A gate and fet1.png I think i'l stick to that speed because it worked fine in terms of overshoot and heating of the FET-s, the low freq wave was probably ringing between DC link caps and decoupling caps I'l next week try snubber...
by Mihai_F
Oct 14 2021 3:53am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

When testing the v1.2 with 4468 fets i had 6 nichicon 1000uf caps, witch had only about 11A ripple and about 6mohm esr total, and after 2 30min test when power was cycled repeatedly from 10 to 16Kw, the caps did not even get worm, now they had a lot of cooling (prop wash). V1.3 has 6 chemicon KZN se...
by Mihai_F
Oct 13 2021 1:21pm
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

I might work saounds doable, i head some people over the internet somewere trying it, but it might be a mechanical challenge trying to fix the segments in to place, they have to be really sturdy, all the motor torque acts on them...
by Mihai_F
Oct 13 2021 12:22pm
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Yes, the lamination supplyer said that is non orientated grain, witch is a must for motors, the material is m330-50a
by Mihai_F
Oct 13 2021 12:09pm
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

I forgot to mention delta winding
by Mihai_F
Oct 13 2021 12:02pm
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Unfortunately 0.5mm laminations, i coukd not find 0.2mm sadly, so i have 700w loss in heating the iron, the stack is 40 mm hight, hence 40x10x5 magnets, so 80 pieces per set, i only got money for 2 sets at that time, stator is 192mm diam 30 slots and 40 magnets, ABC winding scheme trapezoidal BEMF, ...
by Mihai_F
Oct 13 2021 11:33am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

I got them cut in italy, i have to search for that complany, and it was 600 euro (in 2016) fo 2 sets preaty pricy, but for 10 sets they asked for 1000 euro... It ain't cheap, but considerind that here in europe there is a company that sells this kind of motors (bldc outrunnets) and they asked 1500eu...
by Mihai_F
Oct 13 2021 10:35am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Yep the real thing, 7.7kg, 10uH, 6mohm per phase, 36kv, N45 40x10x5 magnets, stator laminations are laser custom cut.
by Mihai_F
Oct 13 2021 10:22am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

I'm thinking to use polypropylene caps (i have some 1uf 250vac big ones) for decoupling or ceramics, but i'm afraid of those becose they fail with no worning and are kinda distructive, aldo pp caps are not as good as ceramics at decoupling, il try it and see.
by Mihai_F
Oct 13 2021 10:06am
Forum: Motor Technology
Topic: Building a motor
Replies: 87
Views: 2973

Re: Building a motor

Here is how : https://www.avrfreaks.net/forum/electri ... ltralights, that motor (20kw) has 60x0,5 strands tristed so they stay nice, and was decent to work with.
by Mihai_F
Oct 13 2021 5:23am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

It does have hall current sensor on the positive bus. I have to wap my head aroud and figure how to make a 4 layer power board, i was to fixated on 2 layers. Those small 1uf caps, failed after a while (melted) ESC was fine, then switched to ceramics, haf 4 banks of 5x1uf in parallel, they failed too...
by Mihai_F
Oct 13 2021 5:12am
Forum: Motor Technology
Topic: 300A bldc esc, mosfets ringing, help
Replies: 34
Views: 670

Re: 300A bldc esc, mosfets ringing, help

For fault management, i have emurgency battery disconect, the controller is in a 1,5mm thick aluminum enclosure so plasma and fire can not get out of it (i tested it), and if FET-s go shorted the battery has enough energy (4,88Kwh 1200A continous) to vaporize them and anything in the controller that...