Development Of Intelligent Synthetical Protector For Motor Based On DeviceNet

Presently, our motor protect technology is also has a certain gap with advanced countries, whose technical content is low, the breed and the function are few, the parameter accuracy is low, the algorithm of protection is shabby, the productive technology falls behind, traditional protect device can not communicate with the network. Be confronted with advanced product of abroad driving in, our motor protection technology still lacks ability to confront advanced products of abroad and market competition. Consequently, the further studying and extending for motor protect device is imperative.To solve the problem that traditional protect devices can not communicate with the network, this design introduces DeviceNet fieldbus. DeviceNet is a kind of fieldbus which is low-cost and reliable. The fieldbus has complete and open protocol standards, perfect device-level diagnosis and plug-and-play function has greatly improved the communication among instruments, and it makes the interchangeability of similar parts offered by different businesses can be realized. DeviceNet has become the excellent choice for the communication of instruments on device net. Therefore, the technology of DeviceNet is used to develop motor protector in this design so that the work status of the motor and the relevant parameters can be reported timely, then we can track the status and adjust the parameters of the motor protector, ensure the motor working regularly.In the hardware, using LPC2119 of PHILIPS company as the core, design and realize the interface circuits of the motor protector such as power circuit, DeviceNet communication circuit, DeviceNet parameter settings and status indicator circuit, real time clock circuit, LCD circuit, analog acquisition circuit and so on. All of these circuits provide a reliable basis for powerful function of motor protector.In the software, the embedded real-time operating system uC/OS-II is transplanted on LPC2119 successfully, tasks are parted reasonably and the code is also finished. It can realize the functions including data acquisition, data processing, real-time clock, status indicator, man-machine dialogue, output control and so on. Design and realize the DeviceNet communication protocol on the basis of in-depth understanding the protocol. Through the consistency test, the protocol is real-time and reliable.Finally, in view of the misoperation defect of overload protect algorithm currently, a new overload protect algorithm based on fuzzy control theory is proposed. Satisfying result is obtained from the simulation with MATLAB, and the hardware implementation is completed in LPC2119 controller, specific steps are also put forward. The initial laboratory experiments show that the application of fuzzy control used in overload protection can improve the accuracy of the forecast for overload time. It can reduce the number of misoperation of protection devices.