I am using the Odrive Pro with the D312s 330KV motor and an MSP-200-24 power supply. I have a picture of my power configuration below. I am using the Odrive onboard encoder without the thermistor. When viewing the Desmos calculator with a 24V bus, I am suppose to be able to reach 115 rps in a free air configuration.
My problem is that when I run the motor at no load I am only able to get 14 turns/s before a DC_BUS_OVER_VOLTAGE Error. I dont have access to a larger power supply currently but do I need to increase the voltage to reach higher speeds. Is the problem caused by a lack of a brake resistor. I have tried using a S1 with a brake resistor and the results were marginally better. What is the problem with my configuration / setup?
First, the overvoltage trip threshold is set to your supply voltage. This means that even very very small fluctuations in the supply voltage (e.g. caused by regenerated energy) will cause the ODrive to trip and error out. I’d recommend setting the overvoltage trip threshold to about 2-6V above the supply voltage.
Second, it seems like you have some issues with your magnetic encoder mounting. The velocity ripple and corresponding current ripple points to eccentricity in the magnet, or some other field distortion. I’d recommend checking out our magnetic encoder usage guide: Designing for Magnetic Encoders — ODrive Documentation 0.6.11 documentation. I’d expect that running harmonic compensation will greatly help.
Additionally, since you’re not using a regen clamp or any other method of regenerated energy management, I’d recommend setting I_bus_soft_min to zero, which will disallow the ODrive from regenerating any current. This will affect the ODrive’s ability to rapidly brake/decelerate the motor, but it will also protect your power supply from voltage spikes caused by regenerated current.
Hi Solomon, My power supply is rated for 24V with Adjustments up to 28.8 V with overvoltage protection set starting at 30 V. Should I set my voltage trip 2-6V higher (26-30V) than the measured voltage off the power supply or adjust the power supply to provide max voltage of 28.8 V? Thank you for the tip about l_bus_soft_min, is this adjustable in the GUI or only through the API?
The current set up has no load, thus I was attributing the velocity noise due to that, but I will adjust the mounting mechanism and test again.
If your supply’s hard overvoltage is at 30V, that’s great! You can keep the voltage at 24V (you’ll already get 8000 RPM with that, no need to adjust unless you need more), and so then setting the Pro’s trip threshold to around 28-29V is going to be fine (power supplies sometimes shut down on overvoltage, this just saves you a power cycle).
Thank you for the tip about l_bus_soft_min, is this adjustable in the GUI or only through the API?
Either! You can adjust it in the inspector tab of the GUI (just search for I_bus_soft_min on the left and drag it into the middle). Just make sure to save your configuration when you’re done (you can search for save_configuration, drag to middle, and hit “call”) – note this has to be done when the ODrive is in idle, or it won’t have any effect.
The current set up has no load, thus I was attributing the velocity noise due to that, but I will adjust the mounting mechanism and test again.
I’d bet if you run harmonic compensation then it’ll basically solve it as-is!
