Research on output current of interleaved-flyback in boundary conduction mode for photovoltaic AC module application

Compared to DCM, BCM is a more flexible solution in the interleaved-flyback with grid-tied inverter for PV AC module application, due to its higher power level and larger switching frequency bandwidth. But the variable switching frequency of BCM causes it difficult to get exact relationship between ACM output current i_out and reference signal i_ref of interleaved-flyback, which has a great influence on THD of output current. This paper analyzes the functional relation between i_out and i_ref by theoretical derivation, and proposes a design approach of reference signal to decrMPPTease THD of output current. The realization of MPPT is also investigated. Finally, simulation and experiment results are presented, validating the proposed functional relation and design approach.