DC-Bus Ripple Elimination in Single-Phase Grid-Tied Differential Buck Inverter With Reduced Sensor Count

Single-phase H-bridge inverters are commonly used in low-power consumer applications requiring high-quality DC-to-AC conversion. These usually employ bulky and less reliable aluminum electrolytic capacitors (AECs) at the DC side to eliminate the second-order ripple current drawn from the source. In recent years, attempts have been made to actively eliminate the ripple current by reconfiguring the H-bridge inverter as a differential buck inverter (DBI). However, the additional objective of DC side ripple elimination overburdens the inverter with the increased number of sensors and thus compromises system reliability. The present work proposes a control scheme that achieves grid current control and DC side ripple elimination with reduced sensor count. The proposed scheme is validated through experimental results with a 110 V, 50 Hz, 800 W DBI prototype.