Hi all , need desperate help here
Brief description of the problem :
-I am using 4 PWM to control two inverters.
-Each EPWMxA has a fixed 180 deg phase shift with the coresponding EPWMxB
-EPWM1&EPWM4 controls inverter 1 (prefer not to change)
-EPWM2&EPWM3 controls inverter 2 (prefer not to change)
-UPDOWN counter is used (cannot be changed)
-All modules are 50% duty cycled.
Task is to
1) use overlap (voltage cancelation) between EPWM2A & EPWM3A pulses in order to control the output power ( using a PI) .
-100% overlap is : EPWM2A & EPWM3A has no phase shift between them
-0% overlap is : EPWM2A & EPWM3A has 180deg phase shift between them
2) obtain a fixed Phase of 90deg between EPWM1A and the middle point of EPWM2A & EPWM3A over the entire range of the overlap percentage.
The part of the program that generates the percentage of the overlap is irrelevant. The above problem could had been easily solved if leading phase loading were possible.
For example : I set PWM1 master loading at CTR_Zero and all the other slaves.
Assume that 10% overlap gives a TPBHS of 80deg. Thus,
EPwm2Regs.TBPHS.half.TBPHS = +80deg
EPwm3Regs.TBPHS.half.TBPHS = -80deg
