Research On Tunnel Equipment Control System Based On Low-voltage Power Line Carrier Communication

Because of the special nature of the relatively closed environment of tunnel roads,there are great differences in the brightness of internal and external lights.In order to ensure the safety of drivers their internal lighting fixtures need to be kept open during the day.High energy consumption increases the operating costs of highways.In actual operation,the internal lighting of the tunnel is excessive,which is not conducive to driver's driving,but also leads to waste of power.Therefore,it has important theoretical significance and application value to study the energy-saving and intelligent technology of tunnel lighting system.Power line carrier communication technology is used to transmit signals without additional transmission lines,then the tunnel lighting control system based on the power line carrier communication technology is designed and developed.The system is studied from two aspects that are power line carrier communication technology and dimming control strategy.The specific work is as follows:First,the principle of power line carrier communication is introduced,and the characteristics of the power line carrier communication channel are analyzed and summarized.Based on the specific conditions of the project,the OFDM modulation and demodulation communication technology is selected,at the same time,a detailed explanation of its theory.Aiming at the shortcomings of the low estimation accuracy of LS channel estimation algorithm,an inproved LS-FEC iteration channel estimation algorithm is proposed.The matlab simulation results show that the improved algorithm can reduce the bit error rate better than the traditional algorithm.The system selects LME2981 dual-mode chip which uses OFDM algorithm as the core to implement power line signal modulation and demodulation.Next,the tunnel lighting dimming strategy is determined.According to the requirements in the 'Specifications for Lighting Design of Highway Tunnels',date fusion processing is performed on the parameters that affect the interior lighting of the tunnel,including the brightness outside the tunnel,the traffic flow and the vehicle speed.A three-input-one-output fuzzy neural network model is established for dimming control of the illumination brightness at the entrance of the tunnel.Then,a tunnel lighting control system is designed based on LME2981 chip.The system mainly consists of a master-slave controller composed of a modem and an STM32 chip,an LED dimming system,an acquisition device.And a detailed system designs according to the electrical characteristics and functional characteristics.Afterwards,the power line carrier communication function and the dimming function of the tunnel lighting control system are experimentally tested.The results show that the system can realize communication and dimming functions.Finally,the thesis summarizes and clarifies the deficiencies,raising questions and solving ideas.The control system designed in this thesis can be applied to the control of other equipment in the tunnel if it is combined with the actual tunnel conditions.The control method can be applied to smart homes,smart cities and other systems.It has certain research significance and application value.