How to make a open switch fault using ePWM block(Texas instruments c2000)??

I'm trying to make open switch fault situation (or the duty cycle of the high side switch to be 0 while not effects the low side one.) . And I'm using a EPWM block from texas instruments c2000 add-on.

I want a high side switch to be opened not the low side one too.

I did

1) continuous software force to control the high side switch(ePWM-A)..... but it's the highest priority signal that makes ePWM-B signal changed.

Is there any way I could solve this problem??

Answer 1

[Kartik Saxena]

Hi,

I understand that you want a high side switch to be opened not the low side one in a 'EPWM' block from Texas Instruments C2000 add-on.

When using the 'ePWM' module from the Texas Instruments C2000 add-on in MATLAB/Simulink, you have the ability to independently control the high side and low side switches of a half-bridge. To keep the high side switch open while not affecting the low side switch, you can use the 'Action Qualifier' and 'Dead-Band' modules within the 'ePWM' block to configure the desired behavior.

Here are the steps you can follow to configure the 'ePWM' block for an open high side switch without affecting the low side:

1. Configure 'ePWM Action-Qualifier' Submodule:

• Set the Action-Qualifier (AQ) submodule to define the desired action for the PWM output A (high side) and B (low side).
• For the high side (ePWMxA), you can set the action to be taken when the counter is at zero (e.g., do nothing or force low) and what action to take when the counter matches the compare value (e.g., do nothing or force low). This will effectively keep the high side switch open.
• For the low side (ePWMxB), configure the AQ submodule to toggle or follow the PWM signal as desired.

1. Dead-Band Module Configuration:

• If you're using the Dead-Band module, ensure that it is configured so that it does not interfere with the desired operation of the low side switch. The Dead-Band module is typically used to prevent shoot-through by ensuring there is a delay between the turning off of one switch and the turning on of the other.

1. Software Force:

• Use the 'Software Force' feature to force the PWM output to a known state. You mentioned you've already tried using continuous software force, but it affected both ePWM-A and ePWM-B signals.
• Make sure that you are only forcing the state of the high side switch (ePWMxA). The software force register has separate bits for ePWMxA and ePWMxB, so ensure you are not inadvertently forcing both outputs.

1. Trip Zones and Events:

• If your configuration uses trip zones or other events that could affect the PWM outputs, ensure that they are set up not to interfere with the low side operation.

I hope this resolves your issue.

Refer to the following MathWorks documentation for more information about TI C2000 Blockset:

https://www.mathworks.com/help/ti-c2000/index.html?searchHighlight=c2000%20epwm&s_tid=srchtitle_support_results_1_c2000%20epwm

Answer 2

[Hari Krishna T]

Hi,

I am using an F28388D to control a 3-phase full bridge inverter. I am utilizing a code with a state diagram for this purpose. I have a requirement to completely turn off the third leg of the inverter at one point for a few seconds based on inputs from Stateflow. I tried using the software force logic, but I am unable to turn off the switches. The attached diagram shows the settings I have tried for this. I provided an input of 1 to the SW input port whenever I needed to turn off the leg, but it's not working, and I am unable to find any resources on how to implement this.

Is there anyone who can help with this?

Thanks in advance.

Regards,

Kripa