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Feature request - PWM duty cycle

Associate III
Posted on October 24, 2014 at 14:38

Hi Gigi,

my application uses two insulated current sensors. In this configuration, STMCWB does not allow me to enter the maximum duty cycle (Control stage -> Analog inputs -> Phase current feedback -> Maximum modulation). The inverter MOSFET drivers use high side bootstrapping, which requires me to limit the maximum duty cycle, otherwise a stalled motor could cause insufficient high side gate voltage. As diode bootstrapping is the most common way to provide floating high side driver supply, almost all power stages will require duty cycle limitation. However, STMCWB grays out this field and forces it to 100%. I currently help myself by overwriting the setting manually in the right header file (e.g. #define MAX_MODULATION_95_PER_CENT), hoping this has the desired effect.

It would be great if this value could be made changeable STMCWB in all configurations.



ST Employee
Posted on October 27, 2014 at 09:08

Ciao Frank

Thank for your feedbak, we can think about it.

Yes, the workaround that you are using is correct. I can add just anoter trip: try to use a customize template file for workbench. You can simply copy in a working folder the default templates file present in the \working\templates_040000\PMSM\ modify it with the notepad and set the WB to use the modified version Option->Template folder.

With this trick you can save a lot of time.



Associate III
Posted on October 27, 2014 at 09:59

thanks Gigi, undestand and very helpful!

Kind Regards


Laurent Ca...
Lead II

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

Associate III

Is this (actually mandatory) feature integrated in the MCSDK? And if not, what changes have to be made manually?

Any input is very welcome.

Best regards