Improved Power Decoupling Scheme for Single-Phase Grid-Connected Differential Inverter with Realistic Mismatch in Storage Capacitances

Inhalt:
The single-phase differential inverter has been introduced in grid connected application with a differential mode for power transfer and a common mode for actively decoupling the second-order power oscillation. This capability is referred to as power decoupling, which when implemented properly, may prolong the lifespan of the dc source. With applying this topology, the existing works have however done with ideally matched storage capacitance, which is not realistic since the capacitance may suffer parameter drifts duo to time and thermal effect. It is therefore the intention of this paper to analysis the performances degradation with capacitance mismatch, shown that both AC and DC have significant distorted. As a result, a simple improved scheme is then proposed for raising performance of the differential inverter, following the identified mitigation criterion. Simulation and experimental results provided have verified the computation and control scheme developed.