Hybrid Modulation and Power Decoupling Control on Single-Phase Bridge Inverter With Buck-Boost Converter

Single-phase H-bridge inverters provide a convenient and flexibly modulated solution to the dc–ac power conversion at once undergoing an inherent power mismatch between dc and ac sides. This article introduces a novel hybrid modulation technique that combines conventional sinusoidal pulsewidth modulation (SPWM) with pulse energy modulation (PEM) for a new single-phase bridge inverter with active power decoupling based on the front-end buck-boost converter. The proposed single-phase bridge inverter diverts the second-order ripple power into a small film capacitor at the buck-boost converter. The proposed hybrid modulation technique modulates the bridge inverter with PEM under discontinuous conduction mode (DCM) and with SPWM under continuous conduction mode (CCM), thus achieving zero-current turn-on compared with SPWM under DCM and removes a sampling circuit as compared with PEM under CCM. A 400-W single-phase inverter system has been built in Power Simulation (PSIM 11.0) to validate the theoretical analysis. Both hybrid modulation and active power decoupling control have been implemented in the experimental prototype using DSP TMS320F28335. The simulation and experimental results show that the second-order ripple power has been successfully mitigated with active power decoupling control, and the bridge inverter is able to work under both DCM and CCM with hybrid modulation.