How to correct an error "OverVoltage" on position control of a brushless motor with encoder and FOC ?

[Agran.1]

Subject: position control of a brushless motor with encoder and FOC.

I use a B-G431B-ESC1 to do position control on a brushless motor with an encoder and FOC.

I want to make a trajectory from 0 to 276 rad in 0.833s. But currently, I can't make this trajectory. (Error: Overvoltage).

Do you have an idea to understand and correct this error?

Best regards,

Equipement /Informations :

Equipment / Information:

Motor brushless with Encoder

Motor Control WorkBench : Version: 6.0.0

MCU :STM32G431CB

Control Board : B-G431B-ESC1

Power Board : B-G431B-ESC1

Algorithm: FOC

Control Mode : Position Control

Speed Sensor Mode : Quadrature Encoder

[GMA]

Hello,

Is the error trigged at starting or stopping phase?

I supposed that you have already checked the V-bus variation during the test and compared it to the Over-Voltage threshold ...

Best regards.

GMA

[Agran.1]

Hello,

The error occurs during the deceleration of the trajectory.

yes, the V-Bus is stable. And the overvoltage comes at this time.

Best regard

[GMA]

Hello,

If error appears at braking state, it could be that motor regeneration will send an extra voltage on the system and will trig the error. You can confirm it by trying the same trajectory with a longer duration.

As described in the application note below, acceleration and deceleration duration are set according to full duration.

If with a longer period, over voltage does not occur any more, you have then to take into account it by or using a different power board or increasing the threshold if your DC supply is able to accept it.

https://www.st.com/resource/en/application_note/an5464-position-control-of-a-threephase-permanent-magnet-motor-using-xcubemcsdk-or-xcubemcsdkful-stmicroelectronics.pdf

Best regards.

GMA

[Agran.1]

Hello,

Acceleration/deceleration times are defined as 1/3 of the full duration.

For the same trajectory with longer durations there is no problem.

Currently, my motor is running under 12V and the overvoltage threshold is 16.79V.

If I switch the Power to 22V and the overvoltage threshold is 24V, I have the same problem.

How can this regeneration be avoided or reduced or diminished?

Best regard

[GMA]

Hello,

The regeneration at brake period is the fact that at this moment motor becomes a generator.

If your DC supply accepts a "sink" mode or if your power board is connected to a battery you can increase the over voltage threshold in the case that you can not use a longer duration...

Best regards.

GMA

[Agran.1]

Hello,

I understood the regeneration due to braking.

In my future project, the DC power will be a maximum of 12 V without overvoltage possibility.

Do you have a solution to not have this regeneration or to eliminate/dissipate it ?

Can this or another demoboard handle this regeneration?

Best Regards

[GMA]

Hello,

A way to cope with it, is to use a "dissipative brake". This feature is available on IHM028 power board for example...

Regards