Adaptive precise harmonic compensation method and device based on photovoltaic grid-connected system

Abstract

The invention discloses an adaptive precise harmonic compensation method based on a photovoltaic grid-connected system. The method comprises the following steps: detecting output current and an outputvoltage on an AC side of a photovoltaic grid-connected inverter when the photovoltaic grid-connected inverter works at a maximum power tracking point; detecting the remaining capacity of the photovoltaic grid-connected inverter, judging the active power flow directions of different subharmonics, and formulating a compensation strategy; adaptively outputting a to-be-compensated component switch on-off signal according to the remaining capacity of the photovoltaic grid-connected inverter; and achieving precise harmonic compensation by using a repeated double closed-loop controller according tothe switch on-off signal. According to the adaptive precise harmonic compensation method disclosed by the invention, the remaining capacity of the inverter is dynamically tracked according to the external illumination changes, the compensation cost of the photovoltaic inverter can be effectively reduced, and the distortion rate of the grid side harmonics is maximally reduced while making full useof the limited remaining capacity of the photovoltaic grid-connected inverter.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected power generation systems, in particular to an adaptive fine harmonic compensation method based on a photovoltaic grid-connected system. Background technique [0002] Photovoltaic grid-connected power generation system, as a typical application of new energy, can be seen in major cities and even remote areas in my country. Photovoltaic grid-connected power generation devices generally work during the day when there is sufficient sunlight, and are generally disconnected from the grid at night. Such frequent and multiple switching of photovoltaic grid-connected devices is not conducive to the work of the equipment, and will also bring large switching losses, which is also not conducive to the stable operation of the power grid. In practical industrial applications, if two devices are used in one system at the same time, The economic cost is relatively high, and it does not take advantage o...

AI Technical Summary

Problems solved by technology

At present, there is no existing technology research. When the current remaining capacity cannot meet the compensation requirements for all sub-harmonics, the compensation scheme is adjusted in real time according to the dynamically changing remaining capacity, and only the harmonic components that cause pollution to the grid side are compensated.

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