Increasing　the　coupling　coefficient　can　enhance　the　power　density　of　a　wireless　power　transfer　(WPT)　system,　but　it　also　leads　to　the　current　waveform　distortion,　resulting　in　hard　switching　in　the　inverter.　Based　on　prior　research,　this　paper　analyzes　the　soft-switching　conditions　of　the　strong-coupling　se-ries-series　bidirectional　WPT　(SC-SS-BWPT)　system　with　the　full　power　range　under　dual　asymmetric　modulation　by　adjusting　the　rectifier　duty　cycle　to　vary　the　system　output　power.　Through　time-domain　analysis,　the　variation　of　system　power　with　respect　to　the　rectifier　duty　cycle　under　a　90°　phase　shift　is　examined.　It　is　revealed　that,　during　bidirectional　power　transfer　under　a　90°　phase　shift,　the　inverter　can　achieve　soft　switching　regardless　of　changes　in　the　rectifier　duty　cycle,　and　the　conditions　for　achieving　soft　switching　on　the　rectifier　side　are　derived.　The　simulation　shows　that　from　150　W　to　3　kW　under　a　90°　dual-phase　shift,　as　the　secondary　rectifier　duty　cycle　varies　from　10　%　to　90　%,　the　pri-mary-side　current　remains　constant　at　±　1.34　A　during　voltage　transitions,　satisfying　ZVS　conditions,　while　the　secondary　side　achieves　ZVS　over　a　wide　operating　range.　©　2025　IEEE.