Grid-connected inverter control method and system

Abstract

The invention provides a grid-connected inverter control method and system. The method comprises the following steps: detecting and obtaining a busbar voltage; carrying out harmonic eliminating processing on the busbar voltage to obtain a detection voltage; calculating a voltage difference between the detection voltage and a preset standard voltage; generating a standard current according to the voltage difference; obtaining the current at an output end of the inverter, and carrying out filtering processing on the obtained current to obtain a detection current; calculating a current difference between the detection current and the standard current according to the detection current and the standard current; and generating a control signal according to the current difference, wherein the control signal is used for controlling the inverter to generate an output current. The grid-connected inverter control method and system reduce the influence on grid-connected current quality caused by busbar voltage harmonics.

Description

technical field [0001] The invention relates to the field of power electronic control, in particular to a control method and system for a grid-connected inverter. Background technique [0002] With the development of solar energy application technology, the mainstream development trend of photovoltaic power generation system will undoubtedly be grid-connected photovoltaic power generation. As one of the key devices of the photovoltaic grid-connected power generation system, the operating performance of the grid-connected inverter directly affects the safe, reliable and efficient operation of the photovoltaic grid-connected power generation system. Generally speaking, for household medium and small power photovoltaic grid-connected power generation systems, the main circuit of the grid-connected inverter often adopts a single-phase topology to adapt to the single-phase power grid; while for centralized high-power photovoltaic grid-connected power generation system, the main ...

AI Technical Summary

Problems solved by technology

The grid-connected inverter with double-loop control needs to sample the bus voltage in the voltage loop control. The bus voltage of the single-phase grid-connected inverter has two ripples, and the bus voltage of the three-phase grid-connected inverter has six ripples. The nth harmonic in the bus voltage leads to the n+1 harmonic in the grid-connected current. The n+1 harmonic may cause the addition of a new harmonic order in the bus voltage, and the added new harmonic order further affects the grid connection current, thus affecting the quality of grid-connected current

[0004] For how to solve the existing influence of reducing bus voltage harmonics on grid-connected current quality, no effective solution has been proposed so far

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