The Development Of Measuring System For Asynchronous Motor's Operating State Based On Virtual Instrumentation Technology

During the development of motor control, such as the vector control of asynchronous motor, in order to obtain operating state of motor, thoroughly research vector control scheme of asynchronous motor, record and analyze actual running effect, it needs to acquire, save, analyze and display all kinds of signals of asynchronous motor. For above purpose, we must synchronously and constantly acquire several signals, such as stator voltages, stator currents, rotor speed of asynchronous motor and so on, and synchronously save, dynamically display, fully analyze and process the acquired signals. Apparently, the traditional measuring instruments can't satisfy these special requirements. If the digital storage oscilloscope is adopted to record data, it can't resolve two problems: the low storage capacity and the poor data analysis and process. If the virtual instrumentation technology, which combines the computer technology and instrument technology is utilized, the above requirements can be excellently satisfied. This dissertation describes the developing of measuring system for asynchronous motor's operating state based on virtual instrumentation technology, by the measuring requirements of asynchronous motor's control system.This dissertation summarizes the measuring theory of voltage signals, current signals, hardware architecture, software architecture of the measuring system for asynchronous motor's operating state based on virtual instrumentation technology, and discusses the design of hardware circuit and software resolving scheme of this measuring system based on LabVIEW, according to the measuring requirements of given electrical parameters of the actual asynchronous motor control system. Based on scheme composing, I finished the designs and tailors of the virtual instrumentation hardware architecture—the analog signal transmission circuits: the designs and simulations of signal processing card and data acquiring card, the tailors and debugging of their printing circuit cards. Based on hardware design, I finished the designs of virtual instrumentation software architecture—the device driver and user application: the device driver for data acquiring card in Windows 2000 operation system and its communication with virtual instrumentation developing environment—LabVIEW, the user application with stable performance, easy operation in LabVIEW.By meaning of connecting with analog signals of power system, I finished thehardware debugging and software testing of this measuring system. The testing result shows that: the system scheme is integrated, the hardware design and software programming are right, the design requirements are satisfied.This measuring system of asynchronous motor's operating state has carried through a successful experiment for the application of virtual instrumentation technology in the electrical engineering.