Theoretical bifurcation boundaries for Wireless Power Transfer converters

Wireless Power Transfer is an emerging topic which relies in high frequency resonant inverters to inductively transfer power from emitter to a physically separated receiver. Inverters may operate with constant or variable frequency depending on control strategy and soft commutation requirements. Those operating with variable frequency are subjected to a phenomenon known as Bifurcation, which is the occurrence of multiple zero phase angle resonant frequencies that can lead the converter to unstable operating modes. This digest presents a theoretical numerical method to determine equations able to predict the Bifurcation in converters with Series-Series, Series-Parallel, Parallel-Series and Parallel-Parallel resonant topologies. The obtained equations are generalized and valid for any primary quality factor, any secondary quality factor and any coupling coefficient between emitter and receiver. Precise and generalized equations have never been reported in literature until this moment.