Research And Design Of Solar Traffic Signal Controller

In recent years,there are many problems in urban traffic with increasing number of urban vehicles in China.In order to solve increasing traffic problems,Many cities continue to expand their roads to the suburbs,but it also increases many intersections.In the road expansion,some intersections that do not have time to lay cables also require signal lights to direct pedestrians and vehicles.Therefore,it is very important to study a traffic signal controller with no power supply and convenient maintenance.Traffic signal controller designed in this paper is supplied by solar energy without electricity.It convert solar energy into electrical energy by solar photovoltaic panels,then the battery storage electrical energy,and supply signal lamp the power.Firstly,this paper makes a survey of the current solar signal and the hardware frame of the signal with power supply,then knowing that the signal controls lamp based on the intersection characteristic data that includes the light data of each step(signal status)in a variety of signal cycles.At the same time,it determines the system framework by doing analysis of the design’s functional requirements,which is mainly composed of main control board,driver board and signal lamp and introduces the working principle and data transfer protocol of a new type of field bus named SPI-CAN.The bus has the characteristics of one master to several slave,and is suitable for data communication between the main board and the drive board.The bus uses the CAN transmission line on the physical layer,which ensures the stability of data transmission,so it is selected as the signal control channel in this paper.Secondly,the paper introduces designs of the hardware and software of the main control board,the drive board and the signal lamp.The main board adopts STM32 microcontroller as the core chip,because of its serial peripheral interface,which is convenient for signal machine to download the intersection characteristic data,and its many kinds of low power consumption software design patterns,so it fully meets the low power design requirements of this design.The main board designed in this paper also uses FPGA which integrates multiple circuit modules to assist the STM32 to complete some complicated sequential and logical circuits.for example,the design of SPI-CAN bus host,the collection of RTC information and the control of FLASH module.The driver board is mainly composed of some digital logic circuits,such as the design of SPI-CAN bus slaver,signal status parallel to serial input,controlling signal serial to parallel output circuit.This part of the circuit has complicated temporal logic structure,so adopted FPGA to design.In the circuit design,the paper also provides the thinking of estimating power consumption of the overall design according to the maximum theoretical power consumption of the device,so as to select the appropriate solar photovoltaic panels,storage battery model.In addition,the program of signal characteristic data downloading is designed,which can be used to download different intersection characteristic data when the signal is used at different intersections in the software section.In order to have different brightness at different times,and to achieve the effect of energy saving,the low power control program of the signal lamp is also designed.Finally,the paper determines the test procedure of the whole,then gives the analysis results.The result shows that the solar road traffic signal control machine designed in this paper achieves the desired results.It not only meets the basic requirements,but also meets the low power consumption in the solar cell power supply mode.