Research On The Influence Of Electric Appliances On The Fading Characteristics Of Low Voltage Power Line Channel

Power line communication is considered to be one of the most promising technologies in the smart grid and energy internet,and has large market value.However,the power line is not an ideal medium for information transmission.The characteristics of the power line channel are very complicated,for its serious channel attenuation,strong noise interference,and varied loads.The development of power line communication technology needs to depend on the full understanding of the characteristics of the power line channel.However,at present,there is a lack of research on the load impedance characteristics of power line channel.In addition,the research and development of power line communication products relys on various tests,but a large number of on-site tests will consume enormous human and material resources.In this thesis,the impedance characteristics of the electric appliances load are measured and analyzed,the influences of the load impedance of the electric appliances on the characteristics of the low-voltage power line communication channel are studied.In addition,in order to provide a convenient and effective test environment for power line communication products,a low-voltage broadband power line channel emulator is designed and implemented,which can simulate the power line channel scenario that accesses different electric loads.Firstly,the power line communication technology is briefly introduced,and the characteristics of the low-voltage power line channel is analyzed in this thesis.Then the main power line channel modeling methods are summarized.Secondly,based on vector network analyzer,a time-frequency two-dimension impedance measurement method is proposed in this thesis.Through this method,the impedance characteristics of various types of electric appliances are measured and analyzed.The results show that different electric appliances have different impedance characteristics due to their different circuit structures and working principles.Thirdly,through the bottom-up power line channel modeling method,the influences of the electric appliances on the characteristics of the low-voltage power line communication channel are analyzed.The results show that the electric appliances load is one of the key factors affecting the characteristics of the low-voltage power line communication channel.Finally,based on the System Generator platform,a low-voltage broadband power line channel emulator is designed and implemented by FPGA.The channel emulator can simulate the low-voltage broadband power line channel scenario that accesses different electric loads.It also can meet the requirements of two-way communication.As a result,the implement of the power line channel emulator can provide convenient and effective hardware platform support for the testing of power line communication products.