Simple Enhancement of Series-Series-Compensated Inductive Wireless Power Transfer Links Operating With Load-Independent Voltage Output at Fixed Frequency to Attain Zero Inverter Phase Angle

It is well-known that series-series-compensated resonant inductive wireless power transfer links (SS-IWPTL) may be designed to attain load-independent voltage output (for given operating frequency and coupling coefficient. Unfortunately, the corresponding inverter output impedance is either highly inductive or highly capacitive (inductive region is typically preferred due to natural zero-voltage switching of inverter transistors), significantly increasing inverter volt-ampere (VA) rating. The letter demonstrates that designing the SS-IWPTL for operation in the capacitive region and then adding a shunt inductor across ac-side terminals of either inverter or rectifier allow attaining inverter zero-phase angle, thus minimizing its VA rating.