A photovoltaic grid-connected inverter and a control method for the photovoltaic grid-connected inverter

Abstract

The embodiment of the invention discloses a photovoltaic grid-connected inverter and a control method of the photovoltaic grid-connected inverter, which are used to improve the efficiency of a photovoltaic power generation system. The embodiment of the present invention includes: a plurality of DC-DC converters, a DC-AC converter, a plurality of independent MPPT controllers and a centralized MPPT controller; the plurality of independent MPPT controllers and the plurality of DC-DC The converters correspond one to one, and the independent MPPT controller is used to control the input power of the DC-DC converter; the centralized MPPT controller corresponds to the DC-AC converter, and the centralized MPPT controller is used for Realize the control of the operating state of the DC-DC converter and the output power of the DC-AC converter; after the output ends of the multiple DC-DC converters are connected in parallel, they are connected to the input of the DC-AC converter end connected. In the embodiment of the present invention, the centralized MPPT controller can control the operating state of the DC-DC converter and the output power of the photovoltaic grid-connected inverter, thereby improving the efficiency of the entire photovoltaic power generation system.

Description

technical field [0001] The invention relates to the field of industrial control, in particular to a photovoltaic grid-connected inverter and a control method for the photovoltaic grid-connected inverter. Background technique [0002] The photovoltaic grid-connected power generation system is mainly composed of photovoltaic arrays and grid-connected inverters. The direct current generated by photovoltaic modules is converted into alternating current that meets the requirements of the mains grid through the grid-connected inverter and then directly connected to the public grid. The grid-connected inverter It has the function of maximum power point tracking (MPPT) of photovoltaic modules and grid current control, such as figure 1 As shown, generally speaking, the photovoltaic grid-connected inverter can realize the above two functions through DC-AC conversion. Composition, and the objectively existing component mismatch reduces the power generation of the photovoltaic power ge...

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Problems solved by technology

[0004] However, this kind of photovoltaic grid-connected inverter needs to undergo PWM chopping due to the operation of the DC-DC converter, and the corresponding components will generate losses. There may be a greater power loss of components due to PWM chopping than due to photovoltaic components In the case of loss caused by mismatch, that is, the operation of the DC-DC converter reduces the output power of the photovoltaic grid-connected inverter, that is, reduces the conversion efficiency of the photovoltaic grid-connected inverter, making the efficiency of the photovoltaic grid-connected power generation system lower. decline

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