withInterleaved Complementary Modulation

Anovel interleaved complementary modulation strategy forzero-voltage-switching three-level (ZVSTL)converter is proposed, withwhichthetwoclamping diodes canberemoved fromthebasic ZVSTLconverter andalltheadvantages arekept. Sothecostissavedandthereliability isenhanced. Thecharge balance oftheflying capacitor isanalyzed anda methodto realize voltage balance ispresented. Theoperation principle of theproposed control strategy isvalidated ona600Wprototype converter andthecomparison withthebasic ZVSTL converter isgiven. In orderto complywiththerequirements of the IEC61000-3-2 Class A standard, thepowerfactor correction (PFC)techniques arewidelyused.Formediumpower application, whichisusually withthree-phase input, thethree- phasesingle switch boost converter usually isaninteresting choice foritssimplicity, reliability andlowcost. However, the output voltage ofPFCconverter mayreach800Voreven 1000Vtoreduce theinput current harmonics, whichmakesit difficult tochoose suitable powerswitches forthedownstream dc/dcconverter tosustain thehighvoltage. Zero-voltage- switching (ZVS)PWM three-level (TL)converter proposed in (1)hasovercome this problem asabetter option, inwhichthe voltage stress ofthepowerswitches isonlythehalfofthe input voltage. Recently, research staff hasmademanyefforts toimprove thisconverter. Canales introduced a flying capacitor totheZVSPWM TLconverter sothat theswitching interval oftheouter twoswitches isdecoupled withthat ofthe inner twoswitches, andvice versa(2), thus, thephase-shifted modulation strategy could beemployed. A zero-voltage and zero-current-switching (ZVZCS)PWM TL converter is