Properties and synthesis of passive lossless soft-switching PWM converters

This paper derives general topological and electrical properties common to all lossless passive soft-switching converters with defined characteristics and proposes a synthesis procedure for the creation of new converters. The synthesis procedure uses the properties to determine all possible locations for the resonant inductors and capacitors added to achieve soft switching. Then a set of circuit cells is used to recover the energy stored in these resonant elements. This paper also explains the operation of the circuit cells and the many new passive lossless soft-switching converters. A family of soft-switching boost converters is given as an example of the synthesis procedure. Experimental waveforms are shown for a new soft-switching Cuk converter. Index Terms- Lossless snubber, soft switching, zero-current turn on, zero-voltage turn off