Single-Phase Buck–Boost Inverter With Pulse Energy Modulation

Abstract

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.