Photovoltaic array topological structure, grid-connected system based on photovoltaic array topological structure and photovoltaic array control method

Abstract

The invention discloses a photovoltaic array topological structure, a grid-connected system based on the photovoltaic array topological structure and a photovoltaic array control method. A photovoltaic array comprises a plurality of parallel photovoltaic branch circuits, wherein each photovoltaic branch circuit comprises a module branch circuit and a compensation branch circuit, each module branch circuit is formed by successive series connection of a blocking diode, N photovoltaic modules and a capacitor, and each compensation branch circuit comprises N inductors and N insulated gate bipolar translator (IGBT) bridge arms. All IGBT bridge arms are in parallel connection with the module branch circuit. Each IGBT bridge arm is composed of two IGBTs. N midpoints corresponding to the N IGBT bridge arms are respectively connected with N cathode end points of the N photovoltaic modules through the N inductors. According to the photovoltaic array topological structure, the grid-connected system based on the photovoltaic array topological structure and the photovoltaic array control method, the photovoltaic modules are enabled to reach maximum power output, the problem of power mismatching of the photovoltaic array in a shadow is effectively solved, and output power of the photovoltaic array is improved.

Description

technical field [0001] The invention relates to a photovoltaic array topology, a grid-connected system and a control method, and belongs to the technical field of photovoltaic power generation. Background technique [0002] Energy is the material basis for human survival and development, and plays a key role in social development. However, with the development of society and economy, on the one hand, people's demand for energy is increasing day by day. Environmental pollution caused by energy consumption is a huge challenge, and new energy power generation technology has become a research hotspot at home and abroad to seek solutions to energy problems. Solar energy is a clean, non-polluting natural energy source, and photovoltaic power generation technology is being widely promoted and applied. [0003] The output power of a single photovoltaic module is small. In order to meet the requirements of the load capacity, the photovoltaic modules are usually connected in series o...

AI Technical Summary

Problems solved by technology

The working mode of the photovoltaic array is that in the case of uniform illumination, the bypass diode is in the reverse cut-off state, and the photovoltaic cell works normally; when a photovoltaic cell is shaded, the component voltage becomes negative At this time, the bypass diode connected in parallel with it is turned on, which protects the photovoltaic cell from being broken down by the reverse avalanche current, but at this time the photovoltaic cell bears the reverse pressure and becomes a load, which consumes energy and reduces the output power of the array

[0005] The traditional photovoltaic array structure actually guarantees the normal operation of the photovoltaic array, and it is not an economical and effective optimization method to let the shaded part of the battery consume energy

Moreover, under random shadow conditions, due to the existence of bypass diodes, the voltage and power output characteristics of the photovoltaic array are complicated, and the power-voltage curve has multiple local extreme points, which also causes difficulties in the maximum power point tracking control of photovoltaics.

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