Research On On-line Monitoring And Fault Analysis Of Inverter Current Harmonic

At present,the rapid development of new energy power generation has become the focus of research and development in various countries in the world.The new energy that has a wide range of distribution,clean resources and huge reserves has become the focus of research.The inverter is the key element in the process of new energy power generation.It converts DC power into AC power to directly provide power for the equipment or is injected into the power grid.Therefore,the power quality of the AC power it outputs is directly related to the equipment operating status or power quality of the power grid.Because of the important role of inverters in power generation,on-line monitoring and fault diagnosis of inverters are important for safe production.Therefore,it is very important to investigate the output and quality of AC power output from inverters.Firstly,the background and significance of the online monitoring and fault analysis of the inverter are expounded,and the problems that need to be studied in this paper are put forward according to the research status.The structural principle of inverter power generation system and inverter is analyzed.The related theories of selection criteria and fault analysis of inverter monitoring characteristic are elaborated,and the scheme of online monitoring of inverter is proposed.Second,data analysis is mainly performed on the collected current signals.The shortcomings of the traditional FFT algorithm are analyzed.In order to make up for its shortcomings,the improved windowing method is used for harmonic analysis and the operation speed is improved.By comparing the spectrum analysis,the improved algorithm has obvious advantages and reduces the signal interference.The open-circuit fault analysis is performed using the matching pursuit method for the output current waveform.The relative error between the energy matching and the norm in each decomposition process is used as the eigenvalue,and simulation verification is performed for various situations to verify the correctness of the proposed eigenvector.For the fault feature,the improved SVM training was used to verify the effectiveness.Finally,an online monitoring module design and performance testing method based on LoRa is given.The principle and technical standard of LoRa spread spectrum communication technology are analyzed.The design scheme of the inverter monitoring module is given.The design includes hardware circuit design and LoRa terminal design.The system software workflow and node network application process are designed and tested.The node transmits various performance indicators.The inverter experimental platform was set up,artificially injecting harmonics into the inverter,and the collected current information was analyzed by windowed FFT analysis.The instantaneous reactive power detection method was used to extract harmonics,and the above-mentioned remote detection harmonics were verified.The effective performance.Three sets of fault conditions were tested in the experiment and verified to achieve open-circuit fault verification and to obtain correct experimental performance.