Modular full direct current photovoltaic system and control method thereof

The invention discloses a modular full direct current photovoltaic system and a control method thereof. The system comprises n DC (direct current)-DC converter modules and an MMC (Multi Media Card) centralized inverter, and every DC-DC converter module is connected with an independent control loop and a maximum power tracking control function so as to ensure that a photovoltaic battery pack connected with every DC-DC converter works on the highest point of the output power. According to the modular full direct current photovoltaic system and a control method thereof, a direct current bus is formed by connecting the output ends of a plurality of DC-DC converter modules in series, and the high-power grid-connected power generation function is achieved through the centralized MMC inverter. The direct current bus can effectively reduce the operating loss of the entire system and structurally improve the operating efficiency of the system.