Evaluation of the efficiency of an automated system for testing synchronous round rotor machines

Abstract

On the basis of analysis of normative documents and study of the technological process of tests, an automated system for testing synchronous round rotor electric machines has been developed. This system has a three-level hierarchical structure. Its lower level consists of measurement sensors and actuating units, the middle level is represented by a digital computer system on the basis of the NI PXIe platform by National Instruments, and the highest level is a computerized operator position (COP), which is based on industrial-class PCs. Algorithms and programs for automatic testing of synchronous turbomachines that we developed in the LabVIEW environment form the basis of the virtual instruments of the system. Because of their interconnections, they are combined into a unified software complex (SMTest). The approximation of the synchronous- machine characteristics that were obtained during testing is based on regression equations of different orders and the least-squares method and used in the algorithms to determine the static parameters of a machine. A combined optimizing algorithm, which is based on the least-squares method and the alternating- variable descent method, is used to determine the dynamic parameters of a synchronous machine. To filter possible noise in measuring channels of the voltage and current sensors, a newly developed efficient adaptive method of sliding trigonometric interpolation is used in the algorithms for determining the parameters of sinusoidal signals, which are picked off the voltage and current sensors in steady-state modes, and dots of signal envelopes in transient modes. To reduce the time for obtaining the static characteristics of the machine, the automated system has a designed exciting-current control loop with a PID controller, which provides the desired field forcing. The automated test system’s efficiency was estimated by mathematical simulation of the testing procedure and the experiment. Analysis of the results has shown that the use of this system makes it possible to reduce the complexity of the testing procedure and its duration by a factor of 1.5–1.7, improve the accuracy of the obtained results by a factor of 3–5, and improve testing safety by mitigating risks of injury and emergencies due to incorrect actions of the staff.