Serious FOCer (84V VESC 6 based controller)

Electric Motors and Controllers
shaman   1 kW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Oct 31 2019 6:11pm

6374 15A.JPG
6374 15A.JPG (172.74 KiB) Viewed 2889 times
Now this is a Turnigy 6374 motor. Much higher kV (rpm/v) than the hub motor from before. Measured inductance is about 13uH and measured phase resistance is about 20mOhm. Waveforms are still sinusoidal in general.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by qwerkus » Nov 01 2019 4:20am

Nice progress here. Interesting option to use the controller as charger, but I'm not sure it's worth the trouble: you'd still need a cable to connect the power source (probably 110 or 220 AC main) and a splitter somewhere on the phase wires for a high voltage connector. In my experience, carrying a long cable around is the most annoying part; a small MW LED transformer turned charger is not an issue.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by john61ct » Nov 01 2019 12:00pm

Does the controller-as-charger add intelligent stop-charge control for unattended charging?

That would IMO be worth a lot, as I'm very forgetful and a PSU approach without that would lead to my cooking packs on a regular basis.

I suppose just a HVC CC-only control would be good enough, as long as the balancing issue was otherwise accommodated.

Any suggestions on a simple HVC device that can handle high voltage and say over 25A?

shaman   1 kW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Nov 01 2019 4:09pm

The whole charger feature idea and integrating that capability into a controller does sounds nifty. I'll save it for a future design since I'm too far along with what I'm doing here. I'll put this idea in as a feature request for the VESC project to see by chance if Ben Vedder could work in the code to do so. I think it would be cool for solar charging a battery on a e- vehicle.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by john61ct » Nov 01 2019 5:08pm

High amp charging from shore power would be higher priority I'd think.

Solar takes days and days for just a few miles' range.

And of course only in the right conditions

shaman   1 kW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Nov 25 2019 7:50pm

Beta FOCer assembly station.jpg
Beta FOCer assembly station.jpg (114.55 KiB) Viewed 2503 times
Beta FOCer Control Boards.jpg
Beta FOCer Control Boards.jpg (184.09 KiB) Viewed 2503 times
I'm overdue for an update to everyone.

Beta unit materials have been arriving. The control boards and BOM components are in. Still waiting on the power stage boards. I'll be finishing out the control boards as I wait for the power stage boards. I had the control boards mostly assembled except a few particular passives, the through-hole components, and the TI specific ICs that I get as free samples.

I don't think explicitly said it but I did make the transition to USB C.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by SRFirefox » Nov 25 2019 11:40pm

Looking good! Are you using a reflow oven to do assembly?

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Nov 26 2019 6:48am

I'm just using my little reflow station you see there on the table. I might use an oven for the power stage boards since they're not arriving with any assembly completed at all.

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hillzofvalp   1 MW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by hillzofvalp » Nov 26 2019 5:38pm

a 1S version of this controller would be nice... I have a skateboard hub design for 1S but I blew my VESC6 trying to get it above 100A.. current scaling was an issue as well as the DRV on there kept breaking. but I was able to change the software to allow 1S. I think I separated the power stage supply from the microcontroller to prove the concept...

300-600Arms phase current would be the goal for 1S
Last edited by hillzofvalp on Nov 26 2019 6:42pm, edited 1 time in total.

shaman   1 kW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Nov 26 2019 6:04pm

Unfortunately I won't be designing for 1S(singular cell) power supply. I also don't know how you ever got 1S to work for reasons including but not limited to the DRV alone needing voltage above 4.2V to function.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by hillzofvalp » Nov 26 2019 6:42pm

I powered it with a separate supply I believe.

Is this open sourced? I didn't read the whole thread. Maybe after enough revs of the 15V+ version you'd let me try modifying it.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by john61ct » Nov 26 2019 9:27pm

Why would you want anything under 24 or 36V?

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Re: Serious FOCer (84V VESC 6 based controller)

Post by Feist92 » Nov 26 2019 11:10pm

Let me know when I can throw money at you 😆
I'm really excited for this controller, it's looking awesome so far 👍

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hillzofvalp   1 MW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by hillzofvalp » Nov 27 2019 3:22pm

john61ct wrote:
Nov 26 2019 9:27pm
Why would you want anything under 24 or 36V?
1S is simple and allows for more power dense motor designs with simplified bms. Only down side really is you have to run larger wires.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by qwerkus » Nov 27 2019 3:37pm

Thanks for the update. Heat gun + tweezers :shock: Talk about tedious work !

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Nov 27 2019 3:39pm

Tedious indeed...but it keeps the cost do all of this down.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by Feist92 » Nov 29 2019 2:55am

hillzofvalp wrote:
Nov 27 2019 3:22pm
john61ct wrote:
Nov 26 2019 9:27pm
Why would you want anything under 24 or 36V?
1S is simple and allows for more power dense motor designs with simplified bms. Only down side really is you have to run larger wires.
Thats very much not the case. Simple bms yes but it definitely does not result in more power dense motors, in fact quite the opposite. Its not just larger wires to the motor but the wires in the motor have to be much larger also. The most power dense motors run high voltage and low current for exactly this reason. To avoid going off topic in this thread make your own and Ill answer any questions you have to the best of my ability

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hillzofvalp   1 MW

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Re: Serious FOCer (84V VESC 6 based controller)

Post by hillzofvalp » Dec 02 2019 5:26pm

Feist92 wrote:
Nov 29 2019 2:55am
hillzofvalp wrote:
Nov 27 2019 3:22pm
john61ct wrote:
Nov 26 2019 9:27pm
Why would you want anything under 24 or 36V?
1S is simple and allows for more power dense motor designs with simplified bms. Only down side really is you have to run larger wires.
Thats very much not the case. Simple bms yes but it definitely does not result in more power dense motors, in fact quite the opposite. Its not just larger wires to the motor but the wires in the motor have to be much larger also. The most power dense motors run high voltage and low current for exactly this reason. To avoid going off topic in this thread make your own and Ill answer any questions you have to the best of my ability
The power a motor produces is proportional to RPM and how many amp-turns per slot. a motor wound for high voltage has to have many turns, say 10 turns at 10A (100 amp turns), and in order to fit those 10 turns there is 50% air in the slot. A motor wound for low voltage may have to have 1 turn at 100A, the same amount of amp turns, but still using 50% of slot. howeevr the beauty of 1 turn is that you no longer have to only use 50% of the slot because it's 1 turn... so you can actually fit the same amount of amp-turns but over larger copper cross section.. therefore it's actually more efficient in some cases if the rest of the system has low enough resistance.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by Feist92 » Dec 04 2019 2:08pm

I dont believe thats possible but please prove me wrong in another thread

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Jan 09 2020 12:01pm

So I definitely owe you guys an update. Sorry for taking so long. FYI the following update isn’t the best news…

Bottom line up front is that the 2-board design in both the serious and little FOCers has some issues at high currents. I believe it’s only an issue with the PCB design and not the components being used. It’s unfortunate that this is the case after all this time and work…but I have a plan.

Some of you know about the Cheap FOCer 2 which is another project of mine. My plan is to base the new Little FOCer (84V, 5kW) on this design. It’s basically going to be a 84V version of the Cheap FOCer 2. The Serious FOCer (84V, 10kW) will then just be a beefier version with TO-247 FETs.

I’ve already done some bench testing of similar new single-board designs with satisfactory results. The 10kW controller did 100A FOC easy. The 5kW design did 75A. The only reason I can’t test higher is due to my own bench testing limitations. I still have to go through another round of prototyping so this will take some more time…

I apologize for all this…but I’m not giving up! It’s just going to take some more time for me to crank out a design I am fully confident in. Quality is still a major concern for me and I will not release something I consider inferior.

Beta Testers:
I'll still assume you want in when the times comes unless you tell me otherwise. I'll confirm with you individually closer to when I have units ready.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by peters » Jan 10 2020 10:12am

Can you describe the issue in details? Do you think it's the power PCB layout or coupling between the stacked boards?
I made a few similar boards for testing in the past few years and I know there are issues with the stacked structure but those are mostly manageable, although basically better to prevent them by placing the low voltage circuits far from the switching power circuits.
In my case I could identify 2 main issues:
One is that the multiple GND connections from the controller board to the power FET sources (3 connectors for 3 low side FETs) generate voltage on the controller board GND plane, because the FET sources are not on the same potential during the switching transients. This GND noise can even be rectified on the pin protection diodes of the ICs and raise the supply voltage from 3.3V to e.g. 3.6V or more. It can be fixed with low impedance GND plane on the controller board and adding small serial resistors to the source connectors, i.e. a part of the gate resistor is placed in the source line.
The other one is that the high current switching induces voltage in wire loops on the controller board. The solution was also a low impedance GND plane for shielding on the side of the controller board that faces the power board, and making sure there are only short signal wires (or no wires at all) on this plane and no large loops.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by coleasterling » Jan 10 2020 11:51am

Dang, sorry to hear that! I'm still 100% in, whenever you're ready.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Jan 10 2020 12:03pm

@peters
I'm pretty sure it's due to the long gate drive traces passing from the control board to the power stage thought the pin headers. The motor phase cables pass right the board sandwich in the middle. The DRV throws gate drive faults and dies. I appreciate your insight here! I follow your solutions but it would take a redesign regardless. I figure I might as well simplify the design to a single board, do ideal placement of the gate drive IC with the shortest possible drive tracks, and take advantage of the layout work I've already done with the Cheap FOCer 2. This will make the controller have a slightly larger footprint but I think it's worth it to achieve more reliability, more stability, and easier manufacturing.

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Re: Serious FOCer (84V VESC 6 based controller)

Post by shaman » Jan 10 2020 12:04pm

coleasterling wrote:
Jan 10 2020 11:51am
Dang, sorry to hear that! I'm still 100% in, whenever you're ready.
Cool! Thanks for staying interested!

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Re: Serious FOCer (84V VESC 6 based controller)

Post by nieles » Jan 10 2020 2:37pm

is it possible to disconnect the pcb track (cut the trace) close to the gate driver and close to the mosfet (ie not traveling on an inner layer). do you also have a solid ground point at the gate driver.

if this is the case, i think you will still be able to test these pcb's if you use a twisted pair for the gate signal/gnd from the gate driver to the mosfet.
at least it would be very interesting to see if this will fix the problem.


i just finished watching about 4-5 hours worth of yt videos talking about signal integrity, EMC and how to use this knowledge to design beter PCB's.
the most interesting thing i learnt was this: the energy doesn't move in the traces, but in the space between the traces. and this applies to both signal and power traces (or any electrical connection for that matter) so what you need to do is manage the space between the traces (in 3D) for the whole loop of a signal.

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