how to use two carriers for epwm1a module.

How to use two carriers for a single epwm module. Two 180 degree phase opposition carriers for a single epwms module in a grid fundamental 50 Hz cycle.

Answer 1

[Spoorthy Kannur]

Hi Mandvi,

Could you please clarify the following details:

1. Are you working with a specific microcontroller or DSP (e.g., TI C2000 series) using MATLAB/Simulink Embedded Coder, or are you simulating the PWM generation entirely within MATLAB/Simulink?
2. Are you aiming to generate two complementary PWM signals (180-degree phase-shifted) from a single ePWM module for a particular modulation technique (e.g., SPWM, SVM)?
3. Have you already configured the ePWM module in your model or code? If so, could you share a brief description or screenshot of your current configuration?

Additionally, please refer: https://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Mandvi]

Hi Spoorthy,

I am trying to implement two carriers for sinhle epwm module from matlab. I use F28069M TI dsp microcontroller. I generate PWM signal using matlab/simulink environment. The screenshot of thecarrier I want is attached below. Thank you for your response.

[Mandvi]

[Spoorthy Kannur]

Hi Mandvi,

Thanks for the update. You can try the following:

1. Use ePWM1 as the first carrier.
2. Use ePWM2 as the second carrier, configured with a phase shift = TBPRD/2 (i.e., 180° shift).
3. Both can have identical compare logic.

Simulink configuration:

• Set ePWM2’s Phase Enable = ON
• Set Phase Offset = half of TBPRD.
• Keep same carrier frequency.

Hope this helps.

[Mandvi]

Hi Spoorthy,

This logic is for interleaved carrier. But I do not want interleaved carrier, I want two carriers in a single epwm block. Like for epwm1, for initially 90 degrees, I want carrier one and for the reminaing 90-360 degress, I want carrrier two.

Answer 2

[Spoorthy Kannur]

A single ePWM peripheral supports one carrier/compare behaviour per timer period, so you cannot directly have carrier A for 0–90° and carrier B for 90–360° inside the same TBPRD using one ePWM instance.

You may try the following options:

1. Use the MathWorks Three-phase, Three-level PWM generator block from the “Simscape / Electrical / Control / Pulse Width Modulation” library (recommended for 3-level operation). It’s designed for dual carriers and will generate the correct gating (https://www.mathworks.com/help/sps/ref/pwmgeneratorthreephasethreelevel.html).
2. Use two ePWM modules (ePWM1 = carrier A, ePWM2 = carrier B) running synchronised TBPRD and multiplex their outputs (either hardware mux or software switch using ePWM output routing) at the 90° boundary. This is reliable and keeps carriers stable.
3. If you must use only one ePWM, change CMPA/CMPB (or TBPRD) mid-period using a timed interrupt to swap in the second carrier. This is possible but timing-critical and riskier (must use immediate loads, protect against glitches).

For F2806x:

• If using two ePWMs: keep TBPRD identical and sync the timers (use master/slave sync). Route/steer outputs at the precise phase boundary.
• If using mid-period updates: use ePWM interrupts and immediate load writes to CMPA/CMPB; carefully test for output glitches and dead-time safety.

If this does not resolve the issue, kindly reach out to MathWorks Technical Support for more help (https://www.mathworks.com/support/contact_us.html?s_tid=hp_ff_s_support).