To enhance the use of renewable energy sources such as solar energy, and solve the problem of stable power supply in remote areas or small systems, the need for a stable operation control strategy for independent DC microgrid with PV and a storage system has attracted attention. For underlying control in such a DC microgrid, a unified control method of MPPT and CV mode of PV is proposed. To ensure the stable operation of the microgrid with PV under different illumination and energy storage power conditions, the system working modes of DC microgrid are divided into three according to the different underlying control modes of PV and battery. As for the control mode of the microgrid, a decentralized control strategy is developed, and a distributed control strategy with battery as the center and one-way communication is proposed. The switching method is designed in both control strategies. Finally, simulation and experimental results show that the microgrid working modes and their switching methods proposed can work normally. Compared with the decentralized control strategy, the proposed distributed control strategy improves control performance, ensures economy, and satisfies the reliability requirements of the system. This work is supported by Major Program of National Social Science Fund of China (No. 19ZDA081).