Photovoltaic grid-connected current and DC voltage secondary ripple suppression control system and control method

Abstract

The invention discloses a photovoltaic grid-connected current and DC voltage secondary ripple suppression control system, which includes a photovoltaic array, a PI controller, a grid-connected current controller, a secondary ripple controller and a single-phase photovoltaic grid-connected inverter The grid-connected current controller includes a low-pass filter for integral regulation, a notch filter for compensation regulation and a PI+ repetition controller connected in parallel; the secondary ripple controller includes a proportional resonance control device. Combined with the control method of the present invention, the secondary power disturbance in the photovoltaic grid-connected current can be effectively eliminated, the effective suppression of the secondary ripple component in the DC side voltage and the substantial improvement of the quality of the grid-connected current can be realized, and the required DC The filter capacitor is greatly reduced, which reduces the volume of the system, reduces the cost, and prolongs the service life of the photovoltaic array.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic grid-connected power generation, and relates to a photovoltaic grid-connected current and DC voltage secondary ripple suppression control system and control method for improving the quality of grid-connected current. Background technique [0002] The photovoltaic grid-connected power generation system consists of two parts: a photovoltaic array and an inverter. The photovoltaic array converts solar energy into electrical energy, and the inverter injects electrical energy into the AC grid. Single-phase single-stage photovoltaic grid-connected inverter adopts single-stage energy conversion link, which has the advantages of simple structure, low cost and high system efficiency. Therefore, it has good application and research prospects in household photovoltaic power generation systems. Traditional single-phase single-stage photovoltaic grid-connected inverters, when the grid-connected current is...

AI Technical Summary

Problems solved by technology

This disturbance will cause a large number of secondary ripple components in the DC side voltage. On the one hand, the secondary ripple component in the DC side voltage will cause a large amount of tertiary ripple current in the grid-connected current, thereby reducing the quality of the grid-connected current; On the other hand, it will affect the accuracy of the photovoltaic array MPPT output reference voltage and the service life of the photovoltaic array

Aiming at the shortcomings of single-phase single-stage photovoltaic grid-connected systems, the currently widely used solution is to suppress secondary power disturbances by designing appropriate power decoupling capacitors. This method requires a very large DC filter capacitor, which makes the system volume and cost greatly increase

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