A three-phase non-isolated photovoltaic grid-connected inverter and a photovoltaic power generation system

Abstract

The invention discloses a three-phase non-isolation type photovoltaic grid-connected inverter and a photovoltaic power generation system. The three-phase non-isolation type photovoltaic grid-connected inverter comprises a three-phase full bridge converter and a filter circuit, wherein the three-phase full bridge converter is in parallel connection between two electrode plates of a solar cell panel array, the middle point of a three-phase full bridge converter is connected with the filter circuit, and the other end of the filter circuit is connected with a negative electrode plate of the solar cell panel array. By the adoption of the three-phase non-isolation type photovoltaic grid-connected inverter, the manufacturing cost can be reduced, and the reliability can be improved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a three-phase non-isolated photovoltaic grid-connected inverter and a photovoltaic power generation system. Background technique [0002] Photovoltaic (photovoltaic, referred to as PV), power generation system usually consists of a panel array and a power conversion part (inverter). The inverter completes the maximum power point tracking of the panel (maximum power point tracking, referred to as MPPT) and grid current control. A low-frequency isolation transformer is placed between the inverter and the grid to achieve electrical isolation between the grid and PV, ensuring personal safety, and at the same time providing voltage matching and grid current DC component suppression. However, low-frequency transformers increase volume, mass and cost, and reduce conversion efficiency. Inserting a high-frequency transformer in the front stage of the PV system is an alternative...

AI Technical Summary

Problems solved by technology

However, the elimination of the transformer makes the PV and the grid electrically connected, and the common-mode current may increase significantly, bringing safety hazards

[0004] However, in existing solutions to potential safety hazards caused by large common-mode currents, the inventors have found the following problems in the prior art:

[0005] If the common-mode inductor is directly used to suppress the common-mode current and suppress it below the standard, the required inductance will be large, which will lead to an excessively large volume and high cost of the common-mode inductor.

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