Design procedures for series–series wpt systems: A comparative analysis

The Series–Series (SS) compensation is one of the most commonly employed topologies for enhancing the efficiency of Wireless Power Transfer (WPT) systems. In this topology, two capacitors are connected in series with the transmitter and receiver coils. Currently, in the literature, these capacitors are tuned to resonate with the self-inductance of the coils at the nominal frequency. Anyway, analyzing the circuit, another interesting possibility emerges: the calibration of the capacitors to resonate with the leakage inductances of the coupled coils. This approach, currently not investigated in the literature, leads to a system with significantly different characteristics. A comparative analysis between these two methods is lacking in the literature. Therefore, this paper aims to fill this gap by proposing an in-depth comparison between the two design procedures, with the aim of providing useful insights to designers in selecting the most appropriate design technique for their application. The analysis includes both steady-state and transient conditions. In particular, the input impedance, voltage transfer function and the transmission efficiency at different frequencies and coupling coefficients are compared. The theoretical results are validated experimentally. The results obtained are extremely interesting and are particularly useful for selecting the most appropriate sizing technique for a given application during the design phase.