Abstract: A non-isolated three port converter with low voltage constraint and high voltage gain and its construction method are proposed to address the problem of discontinuous and unstable output power of distributed photovoltaics over time. It achieves complete control of power flow between the three ports of photovoltaic cells, batteries and loads. Proposed converter is obtained by combining a boost converter, simplified bidirectional four switch boost/buck converter and a bidirectional boost/buck converter. By reusing components and adding a two-stage voltage boosting structure, TPC can be constructed. Retaining the advantages of high voltage gain, mosfets operating in soft switching state, three port no voltage constraint, and non-coupling control of mosfets. Overcoming the shortcomings of high voltage stress on capacitors, inability to evenly distribute series capacitors, and narrow application range. Analysis was conducted on the working principle, steady-state characteristics, switching device stress, power losses parasitic parameters, and control strategies for switching operating modes under various operating conditions. Finally, build an experimental prototype to verify the correctness and feasibility of the theoretical analysis of the converter.