Comparative Analysis of Two Modulation Strategies for an Active Buck-Boost Inverter

The inverter used in the new energy power generation system should have the ability to adapt a wide range of dc input voltage. Based on the active buck-boost inverter, which consists of a full bridge and boost ac/ac part, two modulation methods are compared: constant boost ratio modulation and dual-mode modulation. Along with the relationship of the input dc voltage and the reference ac voltage, the converter completes buck or boost inversion with different equivalent circuits and there are fewer switches working at high frequency in dual-mode modulation, which is in favor of the system with high efficiency. The current of the inductor and the current stress of the switches are analyzed in this paper. Experimental results are presented to verify that the proposed topology can achieve the dual-mode operation with a wide range of input voltage.