In　this　paper,　a　single-stage　charging/discharging　high-frequency　(HF)　link　DC-AC　converter　with　low-frequency　(LF)　harmonic　suppression　was　proposed.　In　addition,　the　crucial　techniques　were　investigated　and　analyzed　in　detail,　such　as　the　circuit　topology,　analogous-rectifying　unipolar　phase-shifted　control　strategy　with　constant　charging/discharging　current,　steady-state　principles　and　input　second　harmonic　current　suppression.　The　important　conclusions　were　obtained.　The　circuit　topology　is　composed　of　an　input　second　harmonic　current　suppression　circuit　and　a　cascaded　single-stage　charging/discharging　HF　link　DC-AC　converter.　The　control　strategy　rectifies　the　sinusoidal　pulse　width　and　position　modulation　(SPWPM)　waves　of　HF　transformer　to　output　positive/negative　half　cycle　sinusoidal　pulse　width　modulation　(SPWM)　waves　through　the　bi-directional　rectification　circuit,　while　realizing　constant　charging/discharging　current　of　the　battery.　The　input　second　harmonic　current　suppression　circuit　is　an　LrCr　parallel-resonant　circuit,　which　is　connected　in　series　between　the　battery　and　input　filter　capacitor.　Experimental　results　of　the　designed　prototype　show　that　the　proposed　converter　has　the　advantages　of　HF　isolation,　single-stage　bi-directional　charge/discharge,　high　conversion　efficiency　and　small　ripple　of　input　current.　©　2018,　Electrical　Technology　Press　Co.　Ltd.　All　right　reserved.