Photovoltaic system and maximum input power determining method

A maximum input power determining method for a photovoltaic system, wherein the photovoltaic system comprises:

• a Direct Current-Alternating Current (DC-AC) conversion circuit and a plurality of Direct Current-Direct Current (DC-DC) conversion circuits, wherein an input end of each of the DC-DC conversion circuits is configured to connect to a corresponding photovoltaic string, and output ends of the plurality of DC-DC conversion circuits are connected in parallel and connected to an input end of the DC-AC conversion circuit;
• and the method comprises:
• performing a partial Current-Voltage (IV) curve scan on each of the DC-DC conversion circuits, and in a process of the partial IV curve scan, controlling a total input power of the plurality of DC-DC conversion circuits to be consistent with that existing before the partial IV curve scan, to obtain 34 a maximum input power of each of the DC-DC conversion circuits;
• and obtaining a sum of the maximum input powers of all the DC-DC conversion circuits based on the maximum input power of each of the DC-DC conversion circuits, wherein a scanned voltage of the partial IV curve scan is less than an open-circuit voltage;
• wherein the plurality of DC-DC conversion circuits comprise at least a first DC-DC conversion circuit and a second DC-DC conversion circuit;
• the performing a partial Current-Voltage (IV) curve scan on each of the DC-DC conversion circuits, and in a process of the partial IV curve scan, controlling a total input power of the plurality of DC-DC conversion circuits to be consistent with that existing before the partial IV curve scan, to obtain a maximum input power of each of the DC-DC conversion circuits comprises:
• controlling an input voltage of the first DC-DC conversion circuit to change, to perform the partial IV curve scan to obtain a first maximum input power of the first DC-DC conversion circuit, and in a process of performing the IV curve scan on the first DC-DC conversion circuit, adjusting an input power of the second DC-DC conversion circuit, so that a sum of an input power of the first DC-DC conversion circuit and the input power of the second DC-DC conversion circuit is consistent with that existing before the partial IV curve scan;
• and by analogy, obtaining a second maximum input power of the second DC-DC conversion circuit;
• and the obtaining a sum of the maximum input powers of all the DC-DC conversion circuits based on the maximum input power of each of the DC-DC conversion circuits comprises:
• obtaining the sum of the maximum input powers of all the DC-DC conversion circuits based on the first maximum input power and the second maximum input power.