This paper discusses a single-phase inverter with a buck-boost converter for single-phase applications such as photovoltaic (PV) systems. The inverter consists of a buck-boost converter and an H-bridge unfolder circuit. The inverter requires only 1 controllable switch to obtain 100 Hz pulsating DC-link voltage. However, a conventional PV inverter requires two-stage power conversion. Thus, the power conversion efficiency can be increased. The inverter features high compatibility with WBG power devices because of high switching frequency of the buck-boost chopper circuit to minimize the boost reactor. The equivalent impedance of the boost reactor is 0.0077% of the grid impedance. Simulation results, experimental results and the control strategy are discussed. Experiments demonstrate that the proposed inverter can output currents of low total harmonic distortion.