Static characteristics of the three level clamped quasi-resonant converter

A control method for resonant converters operating at fixed switching frequencies is presented, in which an active resonant switch (ARS) and a three-level clamp switch (TLCS) are used. The ARS is derived from the conventional resonant switches by adding an auxiliary switch in order to clamp the resonant inductor voltage at zero, and a TLCS is derived from the ARS by adding a secondary winding and a diode to the resonant inductor to reduce the voltage stresses of the switches. A steady state analysis is performed and confirmed by experiments for a buck quasi-resonant converter controlled by the ARS and the TLCS operating in the zero voltage switching mode