With the increase in photovoltaic(PV) generation penetration ratio, PV generation systems have been widely applied. The existing topologies of PV generation units have fixed overcurrent capacity for each conversion stage, making it difficult to respond to various disturbances on PV and grid sides. This paper proposes a family of reconfigurable modular PV converter with flexible modules switching between the PV, grid, and energy storage(ES) sides via flexible switches. We further study an optimal topology configuration for a non-ES case. It control system and flexible module dispatch strategy are proposed to maximize the utilization of hardware resources under various conditions. The proposed topology and its control strategy enhance the flexibility of the PV generation unit and its overcurrent capability by dispatching optimal numbers of flexible modules in different conversion stage to deal with various disturbances on PV and grid sides. The proposed topology and control system are verified by simulation in MATLAB/Simulink.