TMS320F28335: 28335 PWM output

Hridya I

Intellectual 400 points

Part Number: TMS320F28335

Hi,

I would like to use 28335 for three phase three level inverter control. Kindly confirm the following

1. I need 3 pairs of complementary PWM signals per phase for control

2. Total of 9 pairs of complementary PWM signals for three phase inverter control.

I understand from the forum that it has 6 epwm modules that can generate 6 pairs of complementary PWM signals and the ecap modules can generate 6 more pWMs. Please share whether I can make use of eCap modules to generate 3 pairs of complementary signals so that i can have 6+3=9 complementary PWM signals that i need for control.

regards

Hridya

over 6 years ago

0 Cody Watkins over 6 years ago

TI__Mastermind 42195 points

Hridya,

I could be wrong but building a 3 phase multi-level inverter would only take 6 complementary pairs of PWMs.

For example see the topology here:https://ieeexplore.ieee.org/document/7512290

Are you planning on using a different topology?

When using the eCAP in APWM mode there are some limitations compared to the ePWM. There are less features and less integration into the other modules.

Regards,
Cody

0 Hridya I over 6 years ago in reply to Cody Watkins

Intellectual 400 points

Thanks Cody for the response.

I need 3 ePWM modules per phase as this is a different topology. I am worried whether I should select a higher version of controller which has atleast 16 ePWM modules and all other features as 28335. Any recommendation?

0 Cody Watkins over 6 years ago in reply to Hridya I

TI__Mastermind 42195 points

Hridya,

I would stress that you should look into the eCAP's APWM mode before committing to a controller. It does not have Trip zones, digital compares or a Dead-band submodule.

My recommendation is to use a different device with more ePWM modules, as an added benefit you will likely get some newer features and better integration of the PWM into the device. Please note that the ADC performance changes from device to device too.

Hridya I said:
I am worried whether I should select a higher version of controller which has atleast 16 ePWM modules and all other features as 28335.

Do you need 16 PWM channels, or 16 modules each with 2 pwm channels (32 PWMs in total)?

I don't think we have a device that has enough ePWMs for 32 channels. But F2834x and F2837xx both have at least 18 ePWM modules.

Regards,
Cody

0 Hridya I over 6 years ago in reply to Cody Watkins

Intellectual 400 points

Hi,

I need 3X3=9 epwm modules

0 Cody Watkins over 6 years ago in reply to Hridya I

TI__Mastermind 42195 points

Great, a number of the devices should work for you then.

This page explains it pretty well:
www.ti.com/.../products.html

Regards,
Cody

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28335: 28335 PWM output