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TMS320F28335: TMS320F28335 e-PWM Module Duty Cycle

Emre Ekici
Prodigy 20 points
Part Number: TMS320F28335
Other Parts Discussed in Thread: C2000WARE

Hi,

I use TMS320F28335 microcontroller for inverter applications. I use e-PWM for generating PWM. Also I use ADCIAN3,ADCIAN4,ADCIAN5 pins for sensing ınverter’s current.

I need to sensing ınverter’s over current and reduce the pwm duty cycle according to sensing current.

How can I changing duty cycle according to sensing current? How can I restricted or reduce duty cycle according to over current?

  • 0
    TI__Mastermind 42195 points

    Emre,

    the PWM's duty cycle can be adjusted using the CMPx registers. If you wish to configure the PWM's period that is done with the TBPRD register. These are documented fully in: TMS320x2833x, 2823x Enhanced Pulse Width Modulator (ePWM) Reference Guide (Rev. A)

    You can also find good PWM examples in C2000Ware. "C:\ti\c2000\C2000Ware_2_00_00_02\device_support\f2833x\examples"

    Emre Ekici said:
    How can I changing duty cycle according to sensing current?

    You will need to develop some sort of algorithm to read the currents using the ADC, compute a new duty cycle, and then adjust the PWM period as mentioned above.

    Emre Ekici said:
    How can I restricted or reduce duty cycle according to over current?

    It depends on how you are receiving your over-current input. Look at the Trip-Zone submodule in PWM reference guide found above. It is designed to take an input and quickly shutdown the PWM in unexpected cases. This can be done on a period-by-period basis or can have a latched behavior.

    Regards,
    Cody