The Design And Development Of Intelligent Circuit Breakers Control System Based On CAN Field-Bus

Low-voltage circuit breakers is an important electrical apparatus device used for providing protection for power network and industrial equipments against all types of breakdown such as overload,short circuit and creepage, and controller is the central control unit for measuring and protecting function. The paper focuses on the research of intelligent controller used for low-voltage circuit breaker. After analyzed the insufficiencies of the traditional circuit breaker, the paper develops a new type of intelligent controller based on CAN fieldbus.Firstly,after researching the current situation and the development trend of the circuit breakers, this paper analyzed and pointed out the function limitation of traditional circuit breakers, and expatiated the excellence of intelligent circuit breaker based on fieldbus in the application of protection for power network. Then the technological base of the intelligent controller such as the calculation principle of the electrical parameter, the characteristic of the three section protection for the current, and the CAN fieldbus technology and so on are researched.Secondly, Combined with the national standard GB14048.1～2, the enterprise standard and the design requirement, the overall plan of the intelligent circuit breaker controller based on CAN field bus is proposed. And the hardware circiut such as the main control module, power control module, dial switch parameter enactment module, CAN feildbus communication module and so on are designed and realized. Moreover, after analyzed the shortage of the creepage way in existence, a new researching way of creepage protection based on sampling of MCU and controlling of analog switch is proposed. The constitute principle and realization method of every module circuit are discoursed in detail. The whole schematic diagram of the circuit system is given, and the circuit wafer is made.Thirdly, the overall software design idea is described. According to the hardware principle, the bottom procedure of the system is designed. The realization methods for three section protection, PWM signal regulation of the self-generated power supply and CAN communication procedure are discoursed in detail, the flow chart and code realization are given.Fourthly,with the ICS-08 emluator and the integrated development environment CodeWarrior which are made by Freescale corporation, the system prototype is debugged repeatedly, and the test result is given, the system function is verified. The final test result indicates the designed intelligent circuit breaker achieves the functions such as the three section protection for the current, creepage steady. The technical target of the sharpness regulation for the current and time reaches the expected designed require.