Power electronic converter duty ratio

[Johnjacob]

I have read from several different sources that the duty ratio for a Cuk converter is
(Vo/Vin)=(-D/(1-D)

but several other sources say its:
(Vo/Vin)=(D/(1-D)


which is the correct one...i'm tad bit confused..

 

[KlausST]

Hi,

Consider duty cycle to be positive, Then the upper formula is for negative output voltage.
The lower formula gives positive output voltages.

Klaus

 

[Johnjacob]

Hi,

Consider duty cycle to be positive, Then the upper formula is for negative output voltage.
The lower formula gives positive output voltages.

Klaus

Hi, thanks your reply. Thanks make more sense...how about if the converter is an Ac/ac cuk converter....would be simultaneously valid?