基于plc三相異步電動機變頻設計中英文翻譯-文庫吧資料
2024-08-23 17:52本頁面
【正文】 tric equipment. Nevertheless, this makes the equipment more sophisticated, plex, and power factor controller for a threephase induction motor utilizes PLC to improve the power factor and to keep its voltage to frequency ratio constant under the whole control vector control integrated circuit uses a plex programmable logic device (CPLD) and integer arithmetic for the voltage or current regulation of threephase pulsewidth modulation (PWM) inverters. Many applications of induction motors require besides the motor control functionality, the handling of several specific analog and digital I/O signals, home signals, trip signals, on/off/reverse mands. In such cases, a control unit involving a PLC must be added to the system structure. This paper presents a PLCbased monitoring and control system for a threephase induction motor. It describes the design and implementation of the configured hardware and software. The test results obtained on induction motor performance show improved efficiency and increased accuracy in variableload constantspeedcontrolled operation. Thus, the PLC correlates and controls the operational parameters to the speed set point requested by the user and monitors the induction motor system during normal operation and under trip conditions.2. PLC as a System Controller Programmable logic controllers are modular, industrially hardened puters which perform control functions through modular input and output (I/O) modularity of PLC allows the user to bine generic I/O modules with a suitable controller to form a control system specific to his is most simply understood needs. The operation of a controller by envisioning that it repeatedly performs three steps: a) Reads inputs from input modules b) Solves preprogrammed control logic c) Generates outputs to output modules based on the control logic solutions. Input devices and output devices of the process are connected to the PLC and the control program is entered into the PLC memory .In our application, it controls through analog and digital inputs and outputs the varying loadconstant speed operation of an induction motor. Also, the PLC continuously monitors the inputs and activates the outputs according to the control program. This PLC system is of modular type posed of specific hardware building blocks (modules), which plug directly into a proprietary bus: a central processor unit (CPU), a power supply unit, inputoutput modules I/O and a program terminal. Such a modular approach has the advantage that the initial configuration can be expanded for other future applications such as multi machine systems or puter linking.3. Control System of Induction MotorThe software models generated in the Software Requirements Analysis phase of the development project are refined and embellished in the design
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