Recently, a novel beat frequency modulation strategy has been proposed for microinverter applications. As converters controlled using such modulation schemes involve multiple frequencies, the soft switching behavior of the converter varies with time and is worthwhile investigating. This digest introduces a way to investigate soft-switching behavior in beat frequency modulated resonant power converters. Firstly, soft-switching in series resonant converter-based microinverter is analyzed at various frequencies of operation and different loaded quality factors. Then, a comparative analysis is carried out between beat frequency modulated LLC and series resonant converters regarding soft-switching range, converter gain, and RMS currents. LLC converter showed significant improvement in soft-switching range while maintaining the required converter gains. To validate the theoretical predictions, a 50-W beat frequency modulated series resonant converter is built and tested at various operating frequencies and loaded quality factors. Experimental results are in good agreement with the theoretical predictions.
