Based　on　the　analysis　of　the　inherent　defects　of　the　traditional　single-stage　single-phase　boost　mode　inverter,　this　paper　proposed　a　novel　single-stage　single-phase　boost　mode　of　photovoltaic　(PV)　grid-connected　power　generating　systems.　The　technologies　such　as　circuit　topologies　with　an　additional　energy　storage　inductance　bypass　switch,　two　kinds　of　switching　modes　with　energy　storage　inductance　current　limited,　the　nonlinear　PWM　one-cycle　control　strategy,　energy　storage　inductance　current　limits,　the　switch　state　equivalent　circuit　and　operating　modes　within　one　low　frequency　output　period,　design　of　main　circuit　parameters,　system　modeling　analysis　were　carried　on　the　thorough　theoretical　analysis,　and　the　research　conclusions　were　obtained.　The　additional　bypass　switch　and　its　two　kinds　of　switching　methods　solve　the　problem　of　too　much　energy　of　the　energy　storage　inductor　and　decrease　effectively　the　value　of　the　energy　storage　inductor　and　its　current.　Through　sampling　and　feeding　back　the　inverting　bridge　modulation　currents　in　real-time,　the　nonlinear　PWM　one-cycle　control　strategy　adjusts　the　regenerating　energy　duty　ratio　of　the　inverter,　which　makes　the　average　value　of　the　output　current　of　the　inverter　bridge　in　each　switching　period　to　track　the　reference　sinusoidal　signal　in　order　to　obtain　high　quality　grid-connected　current　waveforms.　The　experimental　results　of　the　designed　and　developed　1kVA　110V/DC-220V/50Hz　prototype　have　conformed　the　feasibility　of　the　proposed　topology　and　control　strategy,　which　provides　an　effective　method　for　single-stage　boost　medium　and　small　capacity　grid-connected　power　generating　fields.　©　2017　Chin.　Soc.　for　Elec.　Eng.