This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Bipolar PWM for BLDC

Other Parts Discussed in Thread: CONTROLSUITE, TMS320F28069

Hi,

I am trying to implement Bipolar 4 quadrant PWM scheme to control a BLDC using six-step control. From what I saw, the examples in controlSUITE seem to be using unipolar 2 quadrant PWM scheme. I am curious if there are other examples for the bipolar scheme.

Meanwhile, I started writing my own code and ran into some issues. Of the two phases that are ON at a particular time, one must be the master and the other must be the slave which is synchronized with the master using appropriate values for SYNCOSEL. From what I see in the reference manual (http://www.ti.com/lit/ug/spruh18d/spruh18d.pdf), EPWM1 could be the master and EPWM2 could be the slave or EPWM2 could be the master and EPWM3 could be the slave. But, what if I wanted EPWM1 to be the master and EPWM3 to be the slave or when I want EPWM3 to be the master and EPWM1 to be the slave, as would be the case when energizing phases A and C? Is it possible to send the SYNC data from EPWM1 to EPWM3 without making it flow through EPWM2?

I would really appreciate any hints on a possible solution. Thanks!

-Tamil

P.S. I am using TMS320f28069 on a custom hardware, with EPWMxA and EPWMxB connected to high and low sides of Phase x in a 3 phase half bridge.