The　large　conversion　ratio　bi-directional　DC-DC　converter　is　widely　applied　in　charge　and　discharge　battery　systems,　automatic　cars,　uninterruptible　power　supplies　(UPS),　generator　systems,　photovoltaic　systems　and　aero　power　supplies,　etc.　The　efficiency,　size　and　cost　are　the　key　properties　for　these　applications.　A　novel　coupled-inductor　bi-directional　DC-DC　converter　is　proposed　and　analyzed　in　this　paper,　which　can　overcome　the　shortage　of　non-isolated　bi-directional　DC-DC　converters　that　its　conversion　ratio　is　restricted　in　a　small　range.　This　paper　analyzes　the　principle　and　control　model　of　the　proposed　converter.　To　accomplish　the　prominent　dynamic　performance　of　the　large　conversion　ratio　bi-directional　DC-DC　converters,　the　different　operating　modes　are　investigated　and　a　improved　control　model　is　deduced　from　one-cycle　control　(OCC)　technique　based　on　effective　duty　ratio　combined　with　optimum　feedback　compensation　strategy.　The　novel　converter　combined　with　improved　OCC　control　strategy　is　built.　The　computer　simulation　and　experimental　results　verify　the　higher　efficiency,　good　robust　and　fast　response　performance　of　the　proposed　circuit　and　its　improved　control　strategy.　©　2012　Chin.　Soc.　for　Elec.　Eng.