Abstract: A new single-stage non-isolated Buck-Boost inverter is proposed. To make the linear relationship between the input voltage and the modulation wave,a novel nonlinear PWM strategy is adopted. This inverter has a balanced buck-boost capability,which is suitable for applications where the input voltage of the photovoltaic system fluctuates widely. In addition,this inverter uses fewer switching devices. Only one inductor with a small inductance is needed as the energy storage component and does not need electrolytic capacitors,which has the advantages of small volume,low cost,high efficiency,short circuit and simple circuit protection. First,analyze the working principle of the inverter, determine its modulation strategy,then establish its mathematical model,design a closedloop regulator,and finally perform simulation and experimental verification. Through the analysis of simulation and experimental results,it is shown that the inverter has buck-boost capability and is suitable for occasions where the input voltage varies widely.