The Design And Development Of Intelligent Contactor Based On CANopen Field-Bus

AC contactor is one of the most widely used appliances in low voltage electrical system, its performance not only has a direct economic benefit, but also affects quality and resources of power systems. The emphasis of the present research is energy saving, low consumption and protection function of AC contactor. After reviewing and summarizing the development of AC contactor, this thesis devoted to the implementation of new energy-saving solutions about the AC contactor and the design of intelligent control scheme, developed a kind of intelligent contactor based on CANopen fieldbus.Firstly,through analysing the AC contactor’s research status and development trend, the thesis found out the existing gap between domestic contactor and overseas similar product, according to the traditional contactor’s deficiencies such as easy burned, easy misoperation, large energy consumption, poor protection function and so on; and the advantages and improvements from the power electronic technology and fieldbus technology, then proposed a PWM energy conservation technology of energy-saving contactor and a implementation method of CANopen fieldbus technology.Secondly, according to the function requirement and specific indicators, this thesis proposed overall scheme of the intelligent contactor.Meanwhile this thesis designed the hardware system with a core of MC9S08DZ60, provided the whole circuit principle diagram including the main control circuit, energy saving module, signal sampling and modulation module, CANopen communication module, human interface module,power module, elaborated the composition principle of each module circuit and specific electrical circuit.Thirdly,on the basis ofμC/OS - II operating system in embedded platform, combined with the hardware circuit, the thesis developed software system of intelligent contactor. According to the functional division, firstly, it made the credit-all debugging for each task, then distributed priority and accomplished the mutual communication between tasks, finally attained all functions by joint debugging. Embedded software design included portingμC/OS-II in DZ60, the design of each user tasks (PWM energy-saving task,A/D sampling and data processing task, CANopen real-time communications task ), in this part it expounded the realization of CANopen protocol stack and the design of each communication object. Fourthly,the thesis adopted CodeWarrior of freescale company for developing system program,and built the testing platforms of energy-saving module and CANopen slave station’s communication.Made the test and analysis of energy-saving module’s related indicators, realized remote control by sending each command from simulation host, used ZLGCANTest to observe the message on the bus transmission, the results showed that frame ID of these messages, definition of data bytes and operation process of the whole network all meet CANopen norms.The final testing shows that the intelligent contactor which this thesis designed can fulfill stable operation and realize the functions such as energy saving, low consumption, long life and so on, moreover, can conduct real-time monitoring and protect the contactor. This design has achieved the desired goal.