PLC-Based_Monitoring_Control_System_for_Induction_Motor-PLC异步电动机运行监控.doc

Design and Implementation of PLC-Based Monitoring Control System for Induction Motor Abstract：The implementation of a monitoring and control system for the induction motor based on programmable logic controller (PLC) technology is described. Also, the implementation of the hardware and software for speed control and protection with the results obtained from tests on induction motor performance is provided. The PLC correlates the operational parameters to the speed requested by the user and monitors the system during normal operation and under trip conditions. Tests of the induction motor system driven by inverter and controlled by PLC prove a higher accuracy in speed regulation as compared to a conventional control system. The efficiency of PLC control is increased at high speeds up to 95% of the synchronous speed. Thus, PLC proves themselves as a very versatile and effective tool in industrial control of electric drives. Keywords：Computer-controlled systems, computerized monitoring, electric drives, induction motors, motion control, programmable logic controllers (PLCs), variable-frequency drives, voltage control. I. INTRODUCTION Since technology for motion control of electric drives became available, the use of programmable logic controllers (PLCs) with power electronics in electric machines applications has been introduced in the manufacturing automation [1], [2]. This use offers advantages such as lower voltage drop when turned on and the ability to control motors and other equipment with a virtually unity power factor [3]. Many factories use PLCs in automation processes to diminish production cost and to increase quality and reliability [4]–[9]. Other applications include machine tools with improved precision computerized numerical control (CNC) due to the use of PLCs [10]. To obtain accurate industrial electric drive systems, it is necessary to use PLCs interfaced with power converters, personal computers, and other electric equipment [11]–[13]. Nevertheless,