Bit confused now, it seems to be fine running on DC mode at the max my power supply can manage, about 130A. BLDC mode also seems to be ok,. But FOC causes it to disconnect from vesc tool when I go past like 30A.
Need some help with updating Firmware.
Using the latest Vesctool 2.0 , A200S is V1.2 :
When i hit Autoconnect this message shows up :
When i change to Firmware Tab there is no includet Files :
Without connected A200S it shows me many includet :
Dont wanna do something wrong at this point, really looking for advice.
One more silly question, is the orientation of Servo Wire correct on A200S :
Thanks in advance
I was able to link the pics of motor->general. Thanks again for your help.
DIsconnects under load usually happen due to spikes and coupling to the USB. I had that happening in my early prototypes. Not happening anymore after I separated the control board from power and moved the USB connector away from high current paths. Are you running a brushed motor in DC mode? Also, how do you variate and pulse current to a single phase in your tests? Is that from the experiments tab?
Thank you for your quick response. This is a brushless motor. For my tests I have been simply using a hand-held, wireless remote designed for electric skateboarding to . It plugs into the PPM port.
All looks good to me except one thing. Max input voltage is set at 63v while your pack can charge up to 67v. If you happen to charge above 63v, you will overvoltage faults and the motor will not run.
Also, on another end, see how the voltage drops when you open the throttle. If it drops too much, you may be hitting cutoff levels which are 54-49v in your case.
I reply to my own post.
Used VESCtool 0.91 to get connection with A200S V1.2 without upgrading FW.
It seems that there is no FW on Github for V1.2, so i stuck with this.
I run into new problems (-;
I encountered to late that the Hall Conector Ports are reversed, so i shorted my AS5047 Encoder and the 5V output on A200S i guess. As long USB is plugged in i got power for PPM reciever and blue light on VESC but if i disconnect USB its complete dark!
Also i set up the encoder to 3.2V and A200S put out only 5V , you cant switch here to 3.2V like on VESC6.
I turned around connector housing ....
Took another Encoder which works fine on other VESC6, also set up to 3.2V, diconnect the red wire and took it to COMM Port and plug it in VCC. This works on VESC6 i tested. But it dont work on A200S.
I tested regular HALL sensored Motor and it works fine, so i guess this V1.2 dont support the AS5047 or the FW is the problem.
So what can i do to get the AS5047 to work with my A200S V1.2 ?
Please help me TechAUmNu (-; i tryed to PM you weeks back but get no reply. I really wanna get this beast running but it needs the Encoder Function to work.
Attached Pictures for better understanding what i have done (-:
Voltage drops don't seem to be the problem. I've been looking at the readings from my bluetooth app and comparing them to the loaded performance. When I try to accelerate on loose dirt the motor screems and then shuts down. If I release the throttle it resets and I can try to accelerate again. On the data read out when the motor shuts down it seems to be when the motor current excedes 50A. A "fault: OVER_VOLTAGE" indication occurs at this point. The motor and ESC should be able to handle spikes above 50A. Is it possible that the battery's BMS has a shut down mechanism that triggers at 50A?
Over or UNDER Voltage? Or maybe ABS_OVER_CURRENT? Please verify. If it's overvoltage, then what I said earlier holds true. Your battery voltage is above the limit programmed in controller. You would need either discharge the battery to the level allowed by the limits or bump up the voltage limit of allowed by the hardware limits. Overvoltage under acceleration doesn't make sense to me though because lading up the battery usually leads to either voltage drop and/or overcurrent faults in extreme cases. So, double check the fault code.
Really sorry for not getting back to you sooner on this. I have been trying to get my new boards done and its been very stressful :( but I think they working ok now so I am happy :D
I am not sure how V1.2 will handle new vesc firmware. I don't think I have any working ones left here to test it.
The hall sensor port being flipped was fixed only in new v2.1 and I missed that for ages.
The v1.2 does not have a BEC built in, it was meant to be powered by a bec externally.
I seem to remember that you had to remove the 2.2k pullup resistors on the hall sensor port if you wanted to use encoder (mentioned here https://www.vesc-project.com/node/573), this is the schematic for those boards. https://github.com/TechAUmNu/A200S/blob/master/A200S%20V1.2%20Schematic.PDF
Will try to help you as best I can!
If you set to bldc mode and turn gain to like 0.0005 then it ramps up slowly enough that it tends not to blow up even with terrible problems.
I just modded my logic board to add 11ohm (2x 22ohm in parallel) resistors next to the high side output of the gate driver. Now in DC mode with just a piece of 8AWG wire connected between phase 1 and 3 I can put at least 330A out, could go higher but haven't tried. Not doing that for very long at a time though as I don't have a heatsink yet.
BLDC mode also seems to work fine, I need to test with a big motor under load before I really see how it performs.
FOC is a bitch... I think the modulation that it does doesn't like my very long deadtime at the moment about 2.5uS. It causes all manner of weird problems that are neigh on impossible to track down :(
Here is a video and some pics to show what it looks like and how its gone together. I think you might be right about the noise problem on usb. Although not sure how I can easily fix that since its already on seperate boards! (But physically quite close to high current path) Maybe a shield is a good idea
Over voltage. I ran the battery down just a little. Now it says ABS_OVER_CURRENT when the motor stops. The voltage seems to stay stable throughout the test. When the motor current excedes 45-50A it stops and the fault code says ABS_OVER_CURRENT.
Thom, please upload your motor config file so I can have a look. You can save from the File dropdown menu at the top left. Then upload XML file to dropbox.
I think this is an issue with foc settings and a voltage limit too low masking the real issue.
I believe that this is what you are are asking for. Thank you for your help. I don't know why my name automatically gets signed at the bottom of my replies. It's kind of odd... I'm really not that formal :)
Thanks for getting back to me.
Removed the three resistors today.
Unfortunaly i was not able to setup the Encoder because i managed to break of the USB port by plugging in..... got no clue how this happens
Will report after getting the USB Port fixed.
That motor says it only 1500w? and voltage is 60v so its only actually for 25A nominal. So your setting of 95A seems a bit high?
I changed to 70A motor, 50A battery.
Turned on slow ABS current limit.
Adjusted battery cuttoffs
Set wattage limit to 3000w
Max input voltage to 68v
FOC switching speed to 60kHz, sample in v0 and v7 off
Stator saturation compensation 5%
Hopefully that helps.
So been doing a bit more research and some interesting things...
I found this question on stack exchange (https://electronics.stackexchange.com/questions/60427/calculating-the-pulldown-resistance-for-a-given-mosfets-gate) talking about pulldown resistors, it has some interesting formulas on it that lead me to believe that my required gate resistance to keep the fet off when switching full 70v should be between like 1.2 - 2.5ohms total from gate driver to the parallel gates, so that includes the gate resistors / 3 etc. If that holds true then by increasing capacitance on each gate-source to like 36nF by adding a 20nF cap on each one. I can go to 0.7-6.3 ohms total.
Not sure how accurate that is lol. Since it doesn't really take into account the return inductance of the trace and how much voltage it will produce when driving such a large current on it.
I also tried modeling just the gate charge path in ltspice, with some estimated inductances.
My rough estimation is about 40nH inductance to the furthest mosfet. So when I plug in the gate driver rise time and gate resistances it looks like the return inductance will cause a spike on the gate when the gate driver turns on. Playing around with values gives me like >8 ohm on the resistor next to the driver and 8ohm on each gate to stop this spike from being large enough to turn on the gate.
When trying out lots of different values for the series resistor at the weekend, I was seing a 48MHz ringing on the source and gate of the fet. But I put this down to the long probe ground. If I took measurements of both source and gate at the same time then subtracted them it was completely removed. So I think that was a red herring.
I think the crux of all this is that my inductance is far too high for something this high speed and I should probably redo layout to fix it. Only problem is I still have about 50 logic boards assembled, so I don't want to waste those.
Thank you for your help. It's rolling in the dirt now, which is a huge improvement. Although it moves very slowly and the motor screams quite a bit during acceleration. Are there settings that I can play with to see if I can improve the performance?
Horray finally working properly in bldc mode, albeit with 22ohm series and 8ohm on gate with 6uS deadtime lol.
Good enough to use on some project of mine.
For FOC I think you actually need much longer deadtime due to the modulation. It seems to really not like it at all. I have some diodes so I can run the off a bit faster which might make foc work. Also could try changing 8ohm on gate for something a bit smaller.
@Thom I would try tweaking the R and L values up or down by 5-10% one at a time. Start with L and see if that helps at all.
Could also try running the FOC R&L detection again from the FOC page and see what values it gives. (you can actually do this with the wheel on the ground and it might give better result.
I have redesigned the power board to hopefully not suck this time :D
This is some pictures of the new layout. (You might notice the lack of any gate resistors lol)
I am thinking this might be a slightly better way to connect to the middle of the bridge though as it will have lower inductance.
What silicone pad do you use instead PGS? Where can I buy it?
Does logic board of VESC A200 V2.1 suit for power board V2.2 (with TVS diodes)?
@Petja I use these pads https://www.mouser.co.uk/ProductDetail/567-PL-05-5-1016 one pad does about 4-5 boards.
Thank you for information!
I'm in exactly the same position.
I want to be clear, on the 1.2 hardware i need to remove the pullup resistors and reverse the encoder plastics in order to use my hall sensor correct?
The oldest VESC_Tool version i could find was .95 which also gives the same error, any chance someone can link me to the .93 version that will update a 1.2 board?
I'm curious what the newest version of the firmware is that is confirmed to work with the 1.2v hardware. I expect the newest firmwares likely won't work properly, but how new should I go?
Thanks for the help folks
I have archive of older vesc tool versions here: https://drive.google.com/drive/u/0/folders/1naZ1P0zKNlUJFYFJYUAwwXKGMRZ4FwvR
Will be trying to get an updated firmware done for the older boards.
Oh fantastic, .94 gave me a warning about old firmware but let me make some configuration changes. That's a huge step forward. Thanks.
I can stay on 3.37 until a new firmware is released.
I'll stick to sensorless motors on the 1.2v hardware barring some confirmation.
I have some questions about the gate drivers. Most of the application guides are encouraging to keep the trace between gate driver and the mosfet gate as short as possible. Would you consider moving the gate drivers to the power board ? Or is there a specific reason you did not consider this in your architecture ?
Another point is the gate divers are supplied with a 12V source. And the IC in your step down part is MC78M12CDTRKG. When I check the datasheet it has a 500 mA output. Do you think this is enough to power 3 gate drivers for the high switching rates especially when considering those gate drivers supply 4A per phase ?
Hi , very interesting project to follow
I was just curious how did you solder the 10oz FR4 pcbs ? and how did you solder the metal core pcbs ?
does they use normal reflow ? or they need a special house specialized in this ..
The drivers are on the logic board because there was room on that board. TBH thats just where they got put, it might make more sense to move them to power board but there isn't much room and it gets in the way of the high current paths. Now that I have lots of logic boards with drivers already on them I can't really change until I use them all up.
The 500mA is more than adequate, I think it was only drawing about 80mA with all gates going at 60kHz. Page 19 on the gate driver data sheet has calculations you can do. http://www.ti.com/lit/ds/symlink/ucc27211.pdf
Ended up with only 5oz due to track and gap requirements on the directfets, I had them assembled by PCBWAY.
The boards reflow normally with hotplate or reflow oven, just need to keep it at heatsoak temperature (150) for a decent amount of time before going to reflow temps. I reflow all my production boards at home using a Quick 870ESD
@TechAUmNu . thank you for the reply , i didnot know that the hotplate can be used for reflow ( i have a weller WHP 1000 ) that i used for rework. i once used it to solder and i toasted the componenets .
Maybe this is out of subject here , but how do you apply a reflow profile to your hot plate to solder correctly ( is this manual or auto ?_)
One advice i have heard is soldering busbars is not recommended due to thermal stress and different thermal expansion , it is usually better to screw them into the pcb , offcourse you should use plastic shoulders to insulate the busbar from the screw .
My hotplate has a cover that fold onto to turn it into a reflow oven, but there is no fan or controller. I just manually time each step in the profile and cool the boards down with a fan at the end to stop stuff being damaged. All the parts on the boards are quite resilient to heat so it works fine for me.
Yeah I don't use busbars anymore as they were a complete pain to solder, and once on the board make it impossible to rework them. I just use high oz boards. Now moving away from high oz and going towards 2 layer metal core pcbs which are a huge step up in performance.