VESC has died, need help to diagnose reasons

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arvidb
Posts: 231
Joined: 26 Dec 2015, 14:38
Location: Sweden, Stockholm

Re: VESC has died, need help to diagnose reasons

Postby arvidb » 12 Apr 2017, 09:30

You also need headroom for voltage spikes caused by inductance. They are a bit more difficult to estimate though...

rew
Posts: 939
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: VESC has died, need help to diagnose reasons

Postby rew » 13 Apr 2017, 07:42

buran wrote:If I have a mistake in my logic chain, show it me please :)
I fully agree with your logic.

Once there is say 10A running into the motor (i.e. through a highside fet), and the VESC decides to shut that fet off. The "voltage spike" as you call it will cause the voltage on that motor phase to go down to -0.6V until the body diode of the low-side FET turns on. This causes the battery voltage + 0.6V to come across the high-side fet that just turned off. A few hundred ns after this happens, the VESC will turn on the low-side fet to reduce the voltage drop in this part of the circuit to almost zero instead of the 0.6V until that moment.

stigan
Posts: 3
Joined: 20 Sep 2016, 17:47
Location: Sweden, Goteborg

Re: VESC has died, need help to diagnose reasons

Postby stigan » 27 Jun 2018, 18:16

Hello,
I hope to get help via this thread:
Two vesc died after I installed them on a skateboard. Not sure the reason but I set it to FOC controlled with current and regen brake -which I have already broken one other vesc on doing..
The board has no resistance when I attempt to power it from mains - it seems to be shorting out, and current increase to infinite after 3v
This time I can use a flir camera to see that the two components heats up when I power up the board: TC2117 and VP232.
There are no visible burns or broken components. -and there was no smoke when they died (not that I noticed).

Do you think I can just replace the components heating up? -or could the error be rooted in some other component?

RuBisCO
Posts: 3
Joined: 05 Jun 2018, 09:16

Re: VESC has died, need help to diagnose reasons

Postby RuBisCO » 06 Jul 2018, 04:02

stigan wrote:Hello,
I hope to get help via this thread:
Two vesc died after I installed them on a skateboard. Not sure the reason but I set it to FOC controlled with current and regen brake -which I have already broken one other vesc on doing..
The board has no resistance when I attempt to power it from mains - it seems to be shorting out, and current increase to infinite after 3v
This time I can use a flir camera to see that the two components heats up when I power up the board: TC2117 and VP232.
There are no visible burns or broken components. -and there was no smoke when they died (not that I noticed).

Do you think I can just replace the components heating up? -or could the error be rooted in some other component?


What battery or DC power supply voltage were you using?

The DRV8302 most likely failed in some way, and likely taking the buck converter with it. The TC2117 draws its supply from the buck converter and the VP232 is actually the CAN transceiver which draws its supply from the rail the TC2117 is supposed to generate.

The VESC has no transient suppression on the switched nodes so to speak of, so running anything above 10s or more than 36V in conjunction with FOC, which requires higher switching frequencies and fast slew rates, greatly increases the likelihood the VESC will die.

Remove the DRV8302 and those two components, then check to see if the board is still shorting. If the board is not shorting, install a new DRV8302 and check the 5V rail its buck converter is supposed to generate, if that is all good then you should be safe to install a new TC2117 and VP232.

If the board is still shorting when you remove those three components, check the STM32f405RG, D5 (the TVS diode for the 5V rail), and all the capacitors.


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