Abstract: The modular multilevel converter (MMC) has become the research hotspot of large-scale grid-connected photovoltaic (PV) inverter because of its modular structure. However, under different light intensity and temperature, the power generation between PV modules is different, leading to the imbalance of power between bridge arm and phase in MMC. Therefore, this paper first analyzes the performance mechanism of MMC-PV system under power imbalance, and then proposes an optical energy storage routing based on MMC structure. Its control strategy not only satisfies the power requirement of AC and DC ports, but also realizes power self-balancing between bridge arms and phases, which improves PV utilization rate and system stability. At the same time, the configuration constraints of PV and ESS are analyzed in detail due to the influence of power transmission limit of submodules in the bridge arm. Finally, the correctness and effectiveness of the proposed topology and control strategy are verified by simulation and experiments.