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B-G431B-ESC1 Overcurrent

Associate III

Hi everybody,

First of all I don't have experience in FOC.
I have profiled the motor, and the procedure was succesfully completed.
I use the motor profile to create a FOC project.
When I try to start the motor using the Motor Pilot an Overcurrent Error appen (in both mode speed and torque).
Now in normal motor drive the closed current loop regulate the 3-phases motor current by monitoring the current and comparing it to the setpoint created with torque reference respect
to the electrical motor angle, this means that if no short circuit is present, is not possible to get Overcurrent error.

Now in FOC the electrical angle before the motor start must be generated in some way that is not clear to me.

I try to change some paramiter as suggested in the help of Overcurrent error, but nothing change.
Any try give always Overcurrent error.

Using an osclilloscope to investigate, no current flow to the motor phases but systems give this error.

Board is ok because with 6 step methode everything work correct.

Can someone suggest something ?


Hi, this is the resullt with 8 pair pole.

Speed is less then half.

Hello UniRob,

Have the friction and inertia values changed ? If yes, could you try to save the motor with this profiling, and try to make it run as a standard project. Tell me if the OC at start-up still occurs.
Don't worry about the max speed, you can still overwrite it to meet your needs / datasheet via WorkBench afterwards, or even overwrite directly the motor .json file.

If you agree with my answer, please consider accepting it by clicking on 'Accept as solution'.

Hope this will help,
Gaël A.

Hi Geal

the only difference are profiling with 8 pole pair instead of 4 pole pair that give diffente result parametes.

Anyway probably you lost some step.

From my replay of 2024-03-01 12:18 AM the motor is now run (no OC) problem but other problem happen like Over Voltage or Stat up Failure.



Gael A
ST Employee

Hi UniRob,

Sorry I got confused. So to clarify things :
You created a project using your newly profiled motor (8 pole pairs), and now you are able to run the motor. However, you still have Start-up Failures and OverVoltages, am I right ?

At which frequency do the Start-Up Failures occur ? Have you tried tinkering a bit with the Speed PID values ? Do you mind reducing the torque reference at start-up, and increasing the duration ? (Rev-Up tab on MotorPilot GUI) ?

Have you tried running your motor on Open Loop (first voltage then current) mode and get a look at your currents, are they looking good ?

If you agree with my answer, please consider accepting it by clicking on 'Accept as solution'.

Hope this will help,
Gaël A.
Associate III

Hi Geal,

I use 2 repaly to attach all files.

No, I use the project "1 42PMD 4 Pole FOC" attached using the databook motor data and you can see the result in movie 1.

Profiling the motor with 8 pole pair (see attached picture) the speed data and b-EMF are not complient with original motor data at all, and also using the Motor Profile procedure to dectec pole pair, the result is 4 pole pair.

For Overvoltage error I now understand that appen when I reduce the speed, and no ramp are handle by Motor Pilot using speed cursor, so, of course the motor become a generator an increase the BUS voltage.

Using a ramp Overvoltage error does not happen, but when I try to reverse rotation direction event using a ramp Start-up Failure happen.

Using the motor data profiled in project "2 42PMD FOC Profiled " I get Over Current error (see movie 2).

I'm confuse because the procedure to profile the motor give a result that does'not work but seem work using original motor data.

At the moment the problem is "Start-up Failure" when I reverse the rotation directio from CW to CCW.


Associate III

2nd replay