Approximate analysis of the resonant LCL DC-DC converter

An approximate analysis of LCL converters operating above and below resonance is presented. The study based on replacing the rectifier and load by an equivalent parallel resistance, applies the fundamental harmonics method and the assumption that the current through the diodes of the output rectifier has a sinusoidal waveform. Equations obtained for the conduction angle of these diodes (less than pi in Discontinuous and equal to pi in Continuous Conduction Modes) are used for the developing the output to input voltage ratio as a function of three independent parameters. The theoretical results coincide with good agreement with the experiments.