A novel single-stage full-bridge buck-boost inverter

A novel single-stage full-bridge series-resonant buck-boost inverter (FB-SRBBI) is proposed in this paper. The proposed inverter only includes a full-bridge topology and a LC resonant tank without auxiliary switches. The output voltage of the proposed inverter can larger or lower than the DC input one, depending on the instantaneous duty-cycle. This property is not found in the classical voltage source inverter, which produces an AC output instantaneous voltage always lower than the DC input voltage. The proposed inverter circuit topology provides the main switch for turn-on at ZCS by a resonant tank built before the output choke. The nonlinear control strategy is designed against the input DC perturbation and achieves good dynamic regulation. An average approach is employed to analyze the system. A design example of 500 W DC/AC inverter is examined to assess the inverter performance and it provides high power efficiency above 90% under the rated power.