ANALYSIS OF SERIES-PARALLEL RESONANT CONVERTER

A frequency-domain steady-state analysis is given for a series-parallel resonant converter (SPRC) operating in the continuous conduction mode (CCM) using Fourier series techniques. Equations for performance parameters are derived under steady-state conditions to provide simple design tools. The topology of the SPRC combines the advantageous properties of both the series resonant converter (SRC) and the parallel resonant converter (PRC). The key results of the work are: 1) a novel half-wave rectifier SPRC, 2) conditions for obtaining high part-load efficiency, and 3) several boundary frequencies and limiting conditions such as the capacitive/inductive load boundary and open-circuit and short-circuit cases. Experimental results measured for an 80 W converter above the resonance at different load resistances and input voltages show excellent agreement to the theoretical performance predicted by the equations.