A modified modulation for single-phase photovoltaic/battery inverter to improve AC power quality with low DC-link capacitance

Abstract

Abstract The current modulation for single-phase inverter is typically implemented by the assumption of constant DC-link voltage. However, as the inherent double line frequency power pulsation exists in single-phase photovoltaic (PV)/battery inverter, the DC-link voltage often contains double line frequency voltage ripple, which results in distortion of the AC output voltage. In this letter, a modified modulation for full bridge single-phase inverter is proposed. With the new active modulation, harmonics (especially the third order harmonic) in the AC side, are reduced dramatically, and the utilization of low-capacitance DC-link capacitors becomes possible. The effectiveness of the proposed improved modulation is demonstrated by experimental results on a 3\u202fkVA prototype of single-phase PV/battery inverter.