Characteristics of hybrid resonant converter operating on the utility line

A 1-φ high-frequency transformer isolated AC-to-DC controlled rectifier using a hybrid parallel-series resonant converter bridge, operating on the utility line is described. Fixed frequency phase shift and variable frequency control schemes are used to obtain high line power factor and reduced line current harmonic distortion. Based on both approximate AC and state space analysis, design curves are obtained. A design example for 150 W converter is presented. The converter performance is evaluated with SPICE simulation (without active control) and by measurements on the 150 W breadboard model. The line power factor is maintained in the upper 90s with low harmonic distortion (≃16.5% at full load) even without active control. A simple active line current control technique has been used for wave-shaping the line current waveform close to sinusoid, and to reduce the line current total harmonic distortion