Abstract: In this paper,a novel three-phase current source inverter with single-stage Buck-Boost function is proposed by combining Sepic circuit with traditional current source inverter,and the common mode current of the inverter is suppressed by constructing the DCbypass. The proposed inverter topology has the advantages of the ability to realize boosting and bucking,simple and easy to implement modulation,which can be applied to the occasions where the DC voltage range changes greatly like photovoltaic power generation. This paper firstly introduces the circuit topology and working principle of the three-phase Sepic-type current source inverter. Secondly,the expression of the common mode voltage of the inverter at any switching time is deduced,and its common mode current suppression effect is analyzed. Thirdly,the equivalent circuit diagram and mathematical model of the inverter are established,and the Bbuck-Boost capability of the inverter is analyzed in detail. Finally,the effectiveness and feasibility of the proposed three-phase Sepic-type current source inverter and its control scheme are proved by simulations and experiments.