Disturbance observation suppression method for direct-current component of output voltage of photovoltaic grid-connected inverter

Abstract

The invention discloses a disturbance observation suppression method for the direct-current component of the output voltage of a photovoltaic grid-connected inverter. The method includes the followingsteps that: S1, the output voltage amplitude and phase angle reference instruction of the inverter are calculated according to virtual synchronous machine control or droop control, and the componentof a voltage reference value is calculated; S2, the filter capacitor voltage and filter inductor current data of the inverter are collected, a voltage loop / current loop model is established; S3, a generalized controlled object model is established, the filter capacitor voltage data of the inverter are collected, and a disturbance observer is adopted to estimate a direct-current voltage disturbancequantity; S4, a direct-current voltage disturbance estimation value is compensated to modulation voltage signals through feedforward compensation, so that an improved voltage loop / current loop control structure is formed, and the effective suppression of the direct-current component of the output voltage of the inverter is realized. The method has the advantages of parameter design simple, convenient operation, convenience in engineering realization, good suppression effect and high stability. With the method adopted, conventional voltage feedback control and outer loop voltage following performance are not affected.

Description

[0001] Field [0002] The invention belongs to the field of grid-connected control of new energy power generation, and in particular relates to a disturbance observation and suppression method for the DC component of the output voltage of a photovoltaic grid-connected inverter. Background technique [0003] Distributed power generation technology has attracted widespread attention because it can make full use of the region's abundant clean and renewable energy, provide users with "green power", and achieve "energy saving and emission reduction". Power generation technology has become a research hotspot in this field. [0004] Distributed photovoltaics are usually connected to the distribution network through a transformerless non-isolated inverter, because the isolation transformer is omitted, which can reduce costs and reduce power loss, but at the same time it will also cause the DC component in the output voltage of the inverter. question. Due to the non-ideal characteris...

AI Technical Summary

Problems solved by technology

[0006] The present invention is aimed at the problems in the prior art, and provides a disturbance observation suppression method for the DC component of the output voltage of the photovoltaic grid-connected inverter, through the calculation of the component of the voltage reference value-the establishment of the voltage and current double-loop control model-prediction Estimating and judging the amount of DC voltage disturbance—the four steps of establishing an improved voltage-current double-loop control structure to achieve effective suppression of the DC component of the inverter output voltage. The problem of high cost brought by the technical route, and the existing detection and compensation algorithm based on the detection and compensation idea have complex parameter settings, and the impact of the detection and compensation control loop on the overall dynamic performance and stability of the control system is unknown. The suppression method of the DC component of the output voltage of the photovoltaic grid-connected inverter is improved, the method is simple and easy to operate, the suppression effect is good, and the stability is strong

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