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TMDSCNCD28379D: HV-1PH-DCAC

Alican Madan
Intellectual 255 points

Part Number: TMDSCNCD28379D

Hello everyone,

I am currently working on HV1PHDCAC module. In the software, there is piece of code that I am not sure that I understood well. In updateInverterPWM function, piece of code is given below. Function goes into if loop only if duty cycle is expected to be zero. Is this for a smooth transition for zero crossing of the sine wave? If anyone helps I will be thankful. 

if(invDuty==(*ePWM[inv_pwm_no]).TBPRD)
{
invDuty=invDuty-1;
}


Regards

Alican

  • 0
    TI__Mastermind 43730 points

    During the sine cycle , the low frequency switch is switched at the line frequency,

    Because of the way PWM is configured in this design, we need to make sure the go to zero event happens, as it may be overwritten by the go to high event, both of which will happen at TBPRD,

    Refer to the datasheet for the priority of the events,

    Because of the deadband the short 1 cycle pulse never appears on the PWM output.

    There is no soft start for the low frequency switch and hence these is a zero crossing spike in the design.