B-G431B-ESC1 Overcurrent

[UniRob]

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 ?

[Gael A]

Hello UniRob,

Could you provide the MCSDK version as well as the board(s) you are currently using please ?
On another note, could you be more specific on the error behavior ? Is the Overcurrent occurring instantly after clicking on start ?

[UniRob]

MCSDK is 6.2.0

The board is B-G431B-ESC1

The overcurrent occur as soon I press start without delay.

The same appen in torque mode with 0A as soon I press start.

 

[Gael A]

Hello UniRob,

In the B-ESC-G431, the Overcurrent are generated using internal comparators linked to the Timer BKIN. Please make sure the threshold values are coherent, as well as polarity.
Please send me your .stwb6 project file so I can take a look and try to reproduce. Do you have any motor specification to share ?

[madhavP]

Hi Gael A,

I liked your answers and hope you can help me with my problem which is similar to this one.
I am trying to make a motor controller based on B-G431B-ESC1. I have modified the power and current sensing section of the board. I need to increase the over-current and over-voltage protection and the board's overall current and voltage rating in the firmware. However, I am unable to detect which parts of the firmware need to be changed. 

I am using MCSDK-generated firmware for FOC control.
can you suggest something?

Regards

Madhav

[UniRob]

Hi Gaels,

Attached the motor data (42PMD-100-24-x-6.8)

I'm not able to attach .stwb6 file, extension is not permitted, what can I do ?

 

[Gael A]

Hello UniRob,

Normally, copying your .stwb6 file in a .txt file should do the trick.

[UniRob]

Thanks, atrtached the file renamed in .TXT

[Gael A]

Hello again UniRob,

I managed to replicate your project with a fairly similar motor, but unfortunately I can't reproduce your issue.

To be honest I believe your PWM frequency is a bit high but I don't think that's a problem here.
However, be aware that the ESC-G431 board needs to be cooled down (usually with a fan) to prevent any board damage. Also, have you made any hardware modification ?

You mentioned that you managed to profile the motor, could you use the same project, but go to the MotorPilot and try to make it run like this ?

[UniRob]

I try to increase PWM frequency because some times the low inductance of the motor need high frequency to obtain low current riple.

I agry with you that the board need coler, but the first problem is make it running.

I try now to star with the project used to profile the motor deselecting Prifle Mode (see attached file).

Now the motor run but don't follow speed reference (see attached file), seems that the speed detected is reverse, so the motor try go in fuge.

The diffence are that data inserted in Profiles are data taken from motor databook, other project take the data from motor profiled.

RPM 6800 from motor databook 5760 from motor profiled

RS = 0.28 Ohm from motor databook 0.12 Ohm from motor profiled

LS = 0.45 mH from motor databook 0.15 mH from motor profiled

B-emf 3.87V from motor databoot 3.532 from motor profiled

Can be this different parameter the problem ?

If yes why the profiler give this parameters as result ?

Phases order can be other problem for fuge ?

 

Thanks

[Gael A]

Hello UniRob,

I see in your motor Datasheet that its pole pair number is 8. However, in the project you gave me, you put 4 as value. Can you run the Profiler again while inserting the correct Pole Pair value and make a try once again ?

[UniRob]

Hi, this is the resullt with 8 pair pole.

Speed is less then half.

[Gael A]

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.

[Gael A]

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 ?

[UniRob]

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.

Regards

[UniRob]

2nd replay