Research On Temperature Control Circuit Of Railway Locomotives Air Compressors Based On Single Chip Microcomputer

Air compressor is the essential composition device in the Railway locomotive, as the air supply device for all kinds of pneumatic devices and the braking system of the locomotive.The high or low temperature of the compressor's chamber will be directly related to the safety and reliability of the compressor and the efficiency of the locomotive operation,therefore air compressor is very high to the level of fire and explosion and reliability. At present, China's railway locomotive compressor uses traditional relay control way.It only realizes the function of over temperature protection, but can't display and record the working temperature of the compressor.This way make it difficult to prevent the failure in addvance and seach reasons,while can not meet the requirements of modernization. Air compressor often doesn't make any tips to stop work in the locomotive running, which has a serious impact on the normal operation of the locomotive. Therefore, the research on temperature control circuit of railway locomotive compressor has an important practical significance and application value to the safety and reliability work of the compressors.The research of this dissertation is based on the joint development project "Compressor temperature alarm of electric locomotives " with Guangzhou(Railway) Group Company and Chengdu Research Institute of electrical and electronic of China Academy of Railway Sciences to carry out. Considering the field practice of the railway locomotive compressor operation, using the method of single chip microcomputer technology combined with bus control technology and combining with the existed JHJ-? type fire alarm system of locomotive, an intelligent air compressor temperature protection and control system of ARM series of Single Chip Microcomputer as the core controller is designed and developed which is specifically applied to the railway locomotive. The designed system which is on the basis of the original over temperature protection to shut down the compressor, realizes the functions of real time display of compressor temperature, over temperature alarm and data storage and so on. It provides an important basis and intuitive judgment for the locomotive drivers preventing the shutdown of compressor from unknown reason and locomotive maintenance workers judging the compressor fault.The overall scheme design of the system is based on the principles of easy implementation, high reliability, low cost and easy operating. Based on the modular design idea, the two major parts of the design are the hardware and software designs of the system.The main contents of this dissertation are as follows:(1) About the selection of the main electronic components of the system hardware circuit including Single Chip Microcomputer, temperature sensor and bus, the dissertationdecides to adopt STM32F103C8T6 ARM chip as the core controller, PT100 hot resistance as the temperature sensor and RS-485 bus as the communication mode.(2) The design process of the hardware and software in the temperature protection control system of the compressor are discussed in detail in this dissertation under the overall design scheme of the system. It mainly include the module's hardware and software design of the minimum system of the SCM, the acquisition and processing circuit of the temperature,the pressure detecting circuit, the bus communication circuit, the alarm output circuit, and the over temperature control output circuit, but also the software program modification about the temperature display of the fire engine.(3) In order to improve the accuracy of the compressor temperature data acquisition, the filtering process of the compressor temperature data acquisition is designed in this dissertation,completing the simulation and realization which based on Kalman filter in MATLAB.In the laboratory environment, the present designed compressor temperature control system connects the JHJ-? fire engine and temperature sensor by the RS-485 bus to collect compressor temperature in a simulated locomotive environment, and then the comprehensive test is carried on the SS8 locomotive. The test results not only show the stability of data transmission and the feasibility of the cooperation with the JHJ-? fire engine, but aslo verify the developed compressor temperature protection control system achieving the functions of temperature display and over temperature alarm for railway locomotive compressor, meeting the requirements of intelligence and automation of the railway equipment.