The Application Of Embedded PLC In Intelligent Motor Protection System

Intelligent motor protection system integrates protection, measurement and control functions into one system. Three-phase power measurement can be achieved. Its control function is an important function of the motor protection system. It can realize the direct starting, two-way starting and other control modes. It has the sway electric self-starting function and partial restart function. According to the customer demand, control function can be set for different motor runningn set different to control the behavior of the motor. When the system has any fault in the operation process, the motor protection system can timely stop the motor action to ensure safety. At present, several foreign manufacturers such as Siemens, Schneider and other well-known companies have realized the control mode based on embedded PLC. With this system, the customer can use dedicated operating mode to control motor running, and can modify the corresponding operation mode to meet special customer needs. The realization of the control function is flexible to adapt to the special requirements of customers application site. Its implementation also varies depending on the manufacturer, each with its own advantages and disadvantages. Since the design cycle is long and difficult to achieve and maintain, intelligent motor protection control system with embedded PLC in China is still in the research and development stage.This thesis presents the control function design based on embedded PLC programmable technology through detailed design of logic commands. Its realization is based on ARM-based microprocessor embedded platform, achiving a variety of communication interfaces(serial port, Modbus etc.), ten input/output module, which provides the material foundations. Then it introduces the PLC logic command design in details. Finally it describes the implementation combined with PC, a detailed description of the control system in the electric motor protection control system and application process which make the control functions reliable. In the motor running pattern, it has overload protection, direct starting, two-way operation, double speed operation, star/triangle starting five specific mode and one custom operation mode; In the design, a series of motor protections are considered, sway electric restart during running, batch starting, direct conversion, communication lost control and so on.At the same time, through a series of reliability test to proof the reliability. Finally, the result of using the system in many global factories verifies the robustness of motor control function.Achievement of this study is that it puts forward a design way of motor protection based on embedded PLC control function.The design is both from the PLC programming process and from the control model of the application. The thesis has certain reference in terms of embeded PLC control.