A single phase DC-AC dual active bridge series resonant converter for photovoltaic applications

Due to the presence of inherent double-line-frequency power ripple at the AC side, the operation of the maximum power point tracking (MPPT) can be significantly affected in single-phase DC-AC photovoltaic applications. To reduce the ripple power and enhance the MPPT performance, a large capacitor at the DC side is normally used. However, it can decrease the power density of the converter and cannot completely eliminate the ripple power. To mitigate the effect of power ripple, a single phase DC-AC Dual Active Bridge (DAB) converter for photovoltaic applications is proposed. It is free of common large capacitors at DC power stages with the proposed control strategy. In this paper, a LC power decoupling circuit with the specific control strategy is proposed to completely eliminate the ripple power and thus realize high accuracy of MPPT.