This　paper　proposes　a　circuit　topology　of　a　single-stage　three-phase　current-source　photovoltaic　(PV)　grid-connected　inverter　with　high　voltage　transmission　ratio　(VTR).　Also,　an　improved　zone　sinusoidal　pulsewidth　modulation　(SPWM)　control　strategy　and　an　active-clamped　subcircuit　that　can　suppress　the　energy　storage　switch＇s　turn-off　voltage　spike　are　introduced.　The　circuit　topology,　control　strategy,　steady　principle　characteristics,　and　high-frequency　switching　process　are　analyzed　profoundly,　as　well　as　the　VTR＇s　expression　and　design　criterion　of　the　center-tapped　energy　storage　inductor.　The　improved　zone　SPWM　control　strategy　consists　of　two　control　loops,　namely,　the　outer　loop　of　input　dc　voltage　of　PV　cells　with　the　maximum　power　point　tracking　and　the　inner　loop　of　the　energy　storage　inductor　current.　The　experimental　results　of　a　3-kW　96VDC/380V50Hz3φAC　prototype　have　shown　that　this　kind　of　a　three-phase　inverter　has　the　excellent　performances　such　as　single-stage　power　conversion,　high　VTR　and　power　density,　and　high　conversion　efficiency.　Nonetheless,　it　has　small　energy　storage　inductor　and　output　CL　filter,　low　output　current　total　harmonic　distortion,　and　flexible　voltage　configuration　of　the　PV　cells.　This　study　provides　an　effective　design　method　for　single-stage　three-phase　inverting　with　high　VTR.　©　1986-2012　IEEE.