Active Braking Strategy

[rsatterlee]

Posted on October 29, 2015 at 19:11

I am curious how much control we have with the motor braking with SDK. We can of course dissipate extra current with a braking resistor and slow down the motor by shorting the phases. But is it possible for us to actively brake (sometimes called ''chopping'') the motor phases in order to slow them down more quickly than we could by just shorting the phases. And can we directly control the braking 'hierarchy' of which methods will be used?

I didn't see too much configuration or interfacing in the API regarding this topic...We will likely need some sort of a mechanical brake on our application, but we would like to do as much as possible with the motor control to reduce any sort mechanical wear in the system (dismissing the fact that there is additional stress to motor itself).Thank you for any feedback on this.

[Gigi]

Posted on November 02, 2015 at 11:08

Ciao Raddix

We are still in developemt/study regarding this subject. To perform an active barke the only way is to execute a negative torque reference or execute a negative ramp (or step) in the speed reference (the PI speed regulator will generate the negative torque). Then usually we have a regeneration that rise the bus volatge and ''on over volatge'' we can program one of the three behaviours: - Fault condition and stopping the drive turning off the six power switches - Fault condition and stopping the drive turing on the three low side switches (after a Fault acknowlegde the three are switched off) - Continue to drive (breaking) and activate an exetrnal resistor to dissipate the power. There isn't any API that can be used to change this programmed behaviour. Ciao Gigi

[re.wolff9]

Posted on January 10, 2016 at 16:43

The important question is: what kind of power supply do you have? 

If your power supply is ''a battery'', the regenerative breaking is not a problem. Most other power supplies will not be able to push the power anywhere else than in the decoupling capacitors on the power rails. Not sure if it is realistic to have them big enough to hold the mechanical energy of your system, but you can do the math. If that isn't possible.... you have the options that gigi mentions.... 

[Laurent Ca...]

The question has been moved from the "Motor Control Hardware" section to the "STM32 Motor Control" section (the question is about the STM32 MC SDK). 

Best regards