Small-scale　wind　energy　harvesting　from　vortex-induced　vibrations　(VIV)　has　been　introduced　in　recent　years　as　a　renewable　power　source　for　microelectronics　and　wireless　sensors.　Previous　studies　have　focused　on　modeling　and　optimizing　the　VIV-based　piezoelectric　energy　harvester　(VIVPEH)　structures　and　simplified　the　complicated　interface　circuits　as　pure　resistors　with　an　alternating　current　(AC)　output.　In　practice,　an　AC　output　is　required　to　be　transformed　into　a　direct　current　(DC)　followed　by　further　regulations　before　being　used　for　real　applications.　Incorporating　the　rectification　and　regulation,　traditional　theoretical　and　numerical　models　will　become　extremely　cumbersome　and　even　impossible.　To　address　this　issue,　this　work　proposes　an　equivalent　circuit　model　(ECM)　for　a　typical　VIVPEH.　The　Scanlan-Ehsan　aerodynamic　force　model　is　employed　to　describe　the　fluid-structure　interaction.　Wind　tunnel　experiments　are　carried　out　to　validate　the　derived　model.　The　performances　of　the　VIVPEH　with　AC　and　DC　interface　circuits　are　subsequently　analyzed　and　compared　to　understand　the　influences　of　these　circuits　on　the　operational　wind　speed　bandwidth,　power　output,　vibration　amplitude,　and　electrical　damping.