TMS320F280025C: TripZone mean PWM duty cycle measurement

Markus Neumair

Part Number: TMS320F280025C
Other Parts Discussed in Thread: SYSCONFIG

Hello,

I'm using the trip zone of the ePWM module to make my c2000 control the current of a motor.

My setup is : INA (current measurement) >> C2000 CMPSS (defines current setpoint) >> ePWM (uses TripZone to control current)

As I need to calculate the current motor power, I have to determine the duty cycle of the TripZone controlled PWM. Is there a recommended way to do this?

My current code uses a eCAP module that uses a DMA to capture a set of 10 PWM cycles to be able to calculate a mean on time. Anyway, I hope there is a better way to get the mean duty cycle of the trip zone controlled PWM signal.

Best regards,

Markus

over 3 years ago

+1 Nima Eskandari over 3 years ago

TI__Guru 52040 points

Markus Neumair said:
My current code uses a eCAP module that uses a DMA to capture a set of 10 PWM cycles to be able to calculate a mean on time. Anyway, I hope there is a better way to get the mean duty cycle of the trip zone controlled PWM signal.

I was about to recommend capturing the EPWM GPIOs back through input xbar and measuring them through ECAP. The other method is do it using the CLB module.

How are you doing your configuration currently?

Are you using C2000 SysConfig (GUI configuration tool)

Nima

0 Markus Neumair over 3 years ago in reply to Nima Eskandari

Prodigy 185 points

Hello Nima,

my current config uses the input xbar and measures using the eCAP, as you recommended. It's working, but I wanted to figure out if there's a more elegant way.

At the moment I'm not using SysConfig.

Thanks and best regards,

Markus

0 Nima Eskandari over 3 years ago in reply to Markus Neumair

TI__Guru 52040 points

Understood! There is not an internal duty measurement on EPWM. What you have implemented is the way to go!

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TMS320F280025C: TripZone mean PWM duty cycle measurement