Multiple-input fly-back photovoltaic grid-connected inverter

Abstract

The invention discloses a multiple-input fly-back photovoltaic grid-connected inverter. The inverter comprises a plurality of fly-back circuits, a plurality of photovoltaic assemblies, a clamping capacitor, an output filter circuit, an inversion circuit and an electric network. The each fly-back circuit comprises a positive input terminal and a negative input terminal, a clamping terminal, and a positive output terminal and a negative output terminal. The positive input terminal and the negative input terminal of the each fly-back circuit are connected with the positive output terminal and the negative output terminal of the photovoltaic assembly respectively. The clamping terminals of all the fly-back circuits are connected with one end of the clamping capacitor. The output terminals of all the fly-back circuits are connected with each other in parallel and are connected with the output filter circuit. The photovoltaic grid-connected inverter of the invention can be connected with a plurality of photovoltaic assemblies simultaneously. Through one inverter, maximum power tracking of all the photovoltaic assemblies can be realized. All the fly-back circuits share the clamping capacitor, the output filter circuit and the inversion circuit. The inverter has the following advantages that: cost is low; generating efficiency is high; grid-connected current harmonics are low and so on.

Description

technical field [0001] The invention belongs to the technical field of power electronic converters, in particular to the technical field of power converters in the technical field of new energy power generation, and in particular to a multi-input flyback photovoltaic grid-connected inverter. Background technique [0002] The development and utilization of solar energy has become an important measure to solve the problems of energy production and environmental pollution, and can achieve huge economic and social benefits. [0003] Solar photovoltaic grid-connected power generation is the most important way of solar power generation application. The application of solar photovoltaic grid-connected power generation has the advantages of low cost and maintenance-free. According to statistics, more than 90% of the installed capacity of photovoltaic power generation equipment in the world is grid-connected application. [0004] Solar photovoltaic grid-connected power generation sys...

AI Technical Summary

Problems solved by technology

[0006] Due to the low power of a single photovoltaic module (generally less than 300W), the power level of the traditional AC modular photovoltaic grid-connected inverter is correspondingly low, but the corresponding control circuit of the photovoltaic grid-connected inverter needs to complete the MPPT control of the photovoltaic module at the same time , grid-connected current control and various detection, protection and other functions, the cost of this part of the circuit does not decrease with the reduction of the power level of the grid-connected inverter, resulting in the unit power generation of the AC modular photovoltaic grid-connected inverter The cost of power is significantly higher than the cost of grid-connected inverters in traditional centralized, string and multi-string grid-connected power generation systems, thus limiting the promotion and application of AC modular photovoltaic grid-connected power generation systems to a large extent; On the other hand, low-power photovoltaic grid-connected inverters also bring problems such as low energy conversion efficiency of grid-connected inverters and large grid-connected current harmonics.

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