Single-Phase Buck-Boost Inverter With Pulse Energy Modulation

As a popular low-cost solution for achieving both buck-boost and dc-ac conversions in distributed generation systems, the flyback-type buck-boost inverters operating under discontinuous conduction mode (DCM) have linear modulation under low power but bad dc voltage utilization under high power, whereas the buck-boost inverters under continuous conduction mode (CCM) have better dc voltage utilization under high power but more low-order harmonics under low power. In order to combine the advantages of DCM and CCM, a pulse energy modulation (PEM) technique is proposed and studied in this article, enabling the single-phase buck-boost inverter to operate under both DCM and CCM and switch between them seamlessly. The operation principle of the single-phase buck-boost inverter is introduced, and the PEM technique is specifically analyzed and modeled. The small-signal modeling analyses and results of PEM on the buck-boost inverter are compared with the commonly used sinusoidal pulsewidth modulation (SPWM), showing that PEM provides better performance and stability to the investigated single-phase buck-boost inverter.