Brake resistor power rating

1

Hi,

I am facing an issue which seems to have no possible resolution with the any of the setting options. There seems to be an error "BRAKE_CURRENT_OUT_OF_RANGE ", but the user doesnot have any direct control over this limit. I know that we can fiddle around with brake resistance , current limit and requested_current_range, trying to find the perfect combination which will work. But isnt this stupid? There is no direct control over brake current limit but there exists an error which proclaims the same.

Also, if I try to decrease the brake resistance I will encounter “DC BUS OVER VOLTAGE” since the power is being put back to vbus. Why cant there be an option where the user can determine the power rating/maximum current limitations of the attached resistor?

2

Hi Aku!

There are quite a few knobs you can turn in the brake resistor configuration. They’re visible here https://docs.odriverobotics.com/api/odrive.config

Here are the relevant settings with my recommendations

Name Recommendation
max_regen_current No Change
brake_resistance Use the actual resistance printed on the resistor
dc_bus_undervoltage_trip_level No change
dc_bus_overvoltage_trip_level No change
enable_dc_bus_overvoltage_ramp True
dc_bus_overvoltage_ramp_start <power supply voltage + 2>
dc_bus_overvoltage_ramp_end No change
dc_max_positive_current No change
dc_max_negative_current No change
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