This paper introduces a methodology to model and control a single-phase tri state integrated Buck-Boost inverter suitable for low power distributed generation with the capability to operate in grid connected and island modes. The tri-state modulation is adopted in order to achieve power decoupling by means of average inductor current. This way it is possible to control the DC/AC conversion independently of the input current. The proposed strategy considers a multiple loop control scheme, where controllers are tuned based on a linearized models of the system. Main experimental results from a 300W prototype are included and discussed.