Hello,
I need assistance with a brake resistor circuit.
I am currently using an Odrive V3.6 with a 40 KV three-phase motor for 1200 RPM maximum (custom motor from T-motor).
I would like to upgrade to the Odrive Pro but I realize that the brake resistor circuit is not included in the Odrive Pro.
Would it be possible to add an external circuit to the Odrive Pro to allow the power generation of the motor to be dissipated?
Thanks a lot for your help!
Here is a simplified version of how they do it on ODrive V3.6 Brake Resistor Circuit. The microcontroller varies the duty cycle of a 20kHz PWM signal switching a MOSFET to essentially create a variable load which regulates the bus voltage and dissipates the power from braking. You can monitor your power supply voltage and when it rises above a threshold you gradually increase the duty cycle going to the MOSFET.
If you can wait a bit, ODrive S1 has a built-in brake resistor output and might make more sense.
Any news about a brake resistor module for the Odrive Pro?
We’ll need to draw occasionally more than 40A so the S1 isn’t an option.
You can use an S1 as just a brake resistor driver. Or drive a lower power axis with it at the same time.
You just need to put a high curren shottky diode between the power supply and the ODrive shared DC bus, and then the S1 can dump power reactively to the bus voltage. You do need a fair bit of bus voltage margin for this.
Hmmm, that’s doesn’t really make sense to buy a Pro for driving an axis AND a S1 to brake it 
Isn’t there a more cost effective solution planned?
Oh this suggestion mostly makes sense if you have lots of axes. Say you have 6 axes powered by ODrive Pro, and then a single S1 to act as the power management module (together with a shottkey diode to protect the PSU).
How long/often do you need to drive 40A+? It can handle some pulse load, not excessive of course.
This is something I would have to monitor over a longer period. If it’s more than just a peak going +40A there are two hardware related workarounds. The motors are geared down, so one thing would be to increase the reduction gear ratio (which we might do in any case). The second thing would be to increase the system voltage from 24V to 48V. But here’s the question how reliably the S1 can handle load at the nominal limits?
We fried already one v3.6 24V odrive with 24V system voltage.
Well I don’t think we’ve managed to kill one while running at nominal yet. Same with Pro.
Hi @madcowswe,
I already bought an Odrive Pro and I get the DC_BUS_OVER_VOLTAGE, I see a spike in the voltage and that’s caused because I have no resistor to dissipate this power. So what you are saying is that there’s no way to add a resistance or there’s no onboard resistance with the Odrive Pro ? Because in the doc there are some parameters related to that brake resistor, but I can’t find how to implement it with the Odrive pro.
I found those parameters in the doc for the Odrive Pro.
I hope there’s a way to add a brake resistor, because I keep having this issue with the DC_BUS_OVER_VOLTAGE.
Thanks
Hi,
There is no brake resistor circuit on the ODrive Pro. The documentation you are seeing is shared for both ODrive Pro and ODrive S1. The ODrive S1 has a brake resistor circuit.
I get that, but how am I supposed to deal with regen, because when the motor spin in the opposite direction of which the torque is applied, I get a spike of Voltage and then I get an error for over voltage. I think the easy solution would be to have a brake resistor to get rid of the over power ?!
If that’s not possible, what would be the solution with an OdrivePro ?
It’s expected that you have a separate regeneration module on your DC bus, or a power supply which can both source and sink power.
ODrive Pro was designed mainly for battery powered systems, but can also run on a power supply if you have a regen clamp.
Thanks for posting that link!
If you have two Odrive Pros running off of a single power supply, is one of those regen clamps needed or do I need two?
I’m thinking one would serve both motor controllers.
