MC56F8006: How to generate two phase shift PWM signals?

[CarlosCba]

Dears,

I am trying to generate two PWM signals to control an inverter. They must be equals (same duty cycle) with a phase shift of 180°. Can anyone give an idea on how to solve this issue?

Thanks in advance.

[xiangjun_rong · Accepted solution]

Dear Carlos dL,

Regarding your question that you want to use PWM of MC56F8006 to control a an inverter with push-pull layout, I think it is okay, you can connect PWM0 to one MOSFET, connect PWM2 to another MOSFET, PWM1 and PWM3 are not used.

You can set up the PWM0/PWM1 pair in complenmentary mode, PWM2/PWM3 pair in complementary mode, I suggest you use edge-alignment mode, while you set the PCE0 and PCE1 bits in PWM_ICCTRL register. If the PCE0 and PCE1 bits are set, you can use VAL0 and VAL1 to control the rising/falling edge of PWM0 and use VAL2 and VAL3 to control rising and falling edge of PWM2 signals, PWM1 and PWM3 are not used in application.

for example, if the PWM_CMOD=1000, you can set PWM_VAL0=0, PWM_VAL1=250, set PWM_VAL2=500,PWM_VAL3=750, in the above setting, both PWM0/PWM2 will have 25% duty cycle and phase shift 180.

Pls refer to an3844.pdf which can be downloaded from the website:

http://tinyurl.com/kcdrkll

Best Regards,

Xiangjun

[ruimausinho]

Hello,

At first really thank you for share your knowledge about this topic and was really useful. Now i'm trying to make this situation but applied to a 3 phase shift PWM signals, and this case of course for get 120 degrees of shifting. Can i use the same logic? But using the 3 complementary pair of PWM?

With the same logic, i used a valur of PWM_CMOD = 22400 , so i split that value in 6 fractions.

PWM_VAL0 = 0;

PWM_VAL1 = 22400 * (1/5);

PWM_VAL1 = 22400 * (2/5);

.....

PWM_VAL5 = 22400 * (5/5);

Should i use at same edge-align-complementary? Why instead of center-align ??

Is it correct?? It´s a really important academical project, and i need be sure in relation of this.

Thank you in advance,

Best Regards