An adaptive harmonic elimination current control method for a single-phase photovoltaic inverter

Abstract

A method for self-adaptive harmonic elimination current control of a single-phase photovoltaic inverter is provided. The invention is suitable for a two-stage single-phase photovoltaic grid-connectedinverter system connected with a photovoltaic array, a boost converter, an inverter and an inverter controller in turn. For the inverter, the control method comprises the steps of converting the output current of the inverter and the voltage on the grid side in static coordinates to dq rotational coordinates; The state equation of the system in dq coordinate system is listed and the two-loop PI control model of the inverter controller is established. The characteristic harmonic components of the inverter output current are extracted by the harmonic detection module and input to the adaptive neural network control module. The compensation gain is adjusted to compensate the output signal of the double-loop PI control, and the PWM is injected into the inverter to realize the grid-connected control. Grid-connected current distortion of two-stage single-phase photovoltaic grid-connected inverter due to dead-time, DC side fluctuation and other reasons can be overcome, the grid-connected current waveform can be optimized, and the current tracking performance can be improved.

Description

technical field [0001] The invention belongs to the technical field of electrical control, and in particular relates to a single-phase photovoltaic inverter adaptive harmonic elimination current control method. Background technique [0002] The rapid consumption of energy and the increasing pollution of the environment seriously limit the further development of human beings. Photovoltaic power generation is widely used because of its good safety performance, low operation and maintenance costs, easy popularization and wide development range, but it can most affect new The factor of the energy generation system is the pros and cons of the system control performance. At present, the grid-connected current is distorted due to the existence of harmonics in the photovoltaic grid-connected inverter, which makes the design of the grid-connected controller difficult. [0003] Through a large number of database searches such as China National Knowledge Network, Web Of Science, Baidu...

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Problems solved by technology

[0002] The rapid consumption of energy and the increasing pollution of the environment seriously limit the further development of human beings. Photovoltaic power generation is widely used because of its good safety performance, low operation and maintenance costs, easy popularization and wide development range, but it can most affect new The factor of the energy generation system is the pros and cons of the system control performance

At present, due to the existence of harmonics in the photovoltaic grid-connected inverter, the grid-connected current is distorted, which makes the design of the grid-connected controller difficult

[0003] Through a large number of database searches such as China National Knowledge Network, Web Of Science, Baidu Academic, Patent Network, etc., it is found that some patents or journals mainly solve the influence of single harmonics or apply existing algorithms to inverter controllers, such as the invention patent " Method for Reducing Output Current Harmonics of Single-phase Photovoltaic Grid-connected Inverters", Publication No. CN103560656A; Utility Model Patent "A Single-phase Photovoltaic Grid-connected Inverter with Harmonic Suppression", Grant No. CN205792212U; Journal Papers include Liu Jinghui, Zheng Yihui, Yao Gang, et al. published a grid-connected inverter current tracking optimization method based on an adaptive characteristic harmonic elimination strategy, 2013, 28(9): 120-128; Guo Xiaorui, Wang Peiliang, Guo Jifeng published a photovoltaic grid-connected inverter Analysis and control of bus voltage ripple, Electric Power Automation Equipment, 2017, 37(5): 48-53, etc. These patents or journal papers mainly compensate for single harmonics or have a single compensation method, which has low compensation accuracy and resistance to Defects such as weak distortion ability

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