Improvement of input side currents of a three phase rectifier using Cúk converter in discontinuous-capacitor-voltage mode operation

Small-signal model development for a Cúk converter while operating in DCVM for both DC and AC input voltages

“…Switch stress is also an important factor since the converter imposes high voltage stresses to the circuit elements. From (11) one might conclude that a smaller duty cycle greatly improves switch voltage stress, but according to (40) short switching transitions also limits the allowable switching frequency range. Hence duty cycle is limited on 0.6 in order to provide both desirable switching transitions and acceptable voltage stresses.…”

“…As can be seen in (11), this voltage stress is indirectly dependent on the load resistance as the duty cycle can change with load variations.…”

“…In a wide range of input voltage, the converter input port behaves like a linear resistance that provides unity power factor [8]. This approach has also been used in three-phase PFC applications [11].…”