| VFD(Variable- frequency Drive),due to its accuracy, stability in the speed control and many other ad vantages, is recognized as the most promising way of speed adjustment, has been widely used in all kinds of speed regulation system, and its demand will be further expanded. In order to ensure its stability and consistency, it must be strictly detected before delivery. However, continuing expansion of the VFD applications brings the increase and changes in product spec ifications; The rapid development of technology and the change of national standards caused rapid updating of products. In addition, producer for shortening the cycle of new products to the market, often began testing equipment research and development at the prototype stage. All of these bring great challenges for the detection of VFD. With the emergence and rapid development of virtual instrument technique, PCI bus technology, flexible test ideas and some other techniques, it’s possible to make a kind of automated test system which is of high precision, fully functional parts, easy expansibility and strong adaptability.Arming at the problems of existing detection equipment, such as poor flexibility, high complexity, long development cycle, difficulty in upgrading and so on, drawing lessons from recent test technology abroad, based on modular hardware system, fully using flexible testing concept and virtual instrument technology, this thesis is to develop a VFD automatic test system with good applicability, high flexibility and strong expansibility.In the aspect of the system hardware platform design, according to the characteristics of the test signals, this thesis completed the data acquisition card, sensors and other key hardware selection, built a VFD operation platform which can simulate complex working conditions. And the system combine powerful data processing ability of computer with high-precision data measurement ability of PCI data acquisition card efficiently to collect real-time operation parameters and track the operation condition of VFD.Software development and design is the key point of this article. In order to improve the flexibility of the test system and optimize the system performance, the software of this system uses standardized architecture, and adopts the way of LabVIEW calling Test Stand test sequence as the overall structure of the test software to make the system more flexible in the aspects of software architecture, specification and function expansion.In addition, some key function modules involved in the sys-tem are analyzed and software implemented to further improve the test precision and anti- interference ability of the system, such as multi-channel synchronous data acquisition technology, serial port communication and Mod Bus-RTU communication protocol, data analysis and frequency tracking technology. After completing all the tests, the system will automatically generate and print the test report.Finally, the stability and accuracy of the system are analyzed from two aspects of practical operation test and theoretical analysis. After verification, the system can test the 8 shell frame 23 specifications of the VFD, and the power range from 5.5KW to 55 k W, and can be flexible to add or delete the test project according to the test needs. At the same time, the system can also provide protection for the VFD, the test system and testers, and it has the characteristics of stability, safety, reliability, easy to expend and so on, and has better application value. |
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