USING THE COMPARISON OF HARMONIC SIGNALS TO DETERMINE THEIR PARAMETERS

Melent'ev Vladimir Sergeevich, doctor of technical sciences, professor, head of sub-department of information
and measuring equipment, Samara State Technical University, vs_mel@mail.ru
Ivanov Yuriy Mikhaylovich, candidate of technical sciences, senior stuff scientist, sub-department of information and measuring equipment, Samara State Technical University, fuego@rambler.ru
Yudina Elena Georgievna, postgraduate student, Samara State Technical University, yudinec@mail.ru

621.317

The object of the study are the parameters of harmonic signals (PHS): RMS voltage and current, active and reactive power. The subject of the study are methods of determining the PHS based on the formation of additional signals shifted on the phase from the input signals. The aim is to develop a new method for measuring the PHS, which uses a comparison of the input and the additional signals, eliminates the possibility of frequency error when forming an additional signal and provides the ability to start the measurement at any time. To determine the main PHS used as instantaneous values of the input signals and the additional voltage, thereby reducing the measurement time. When analyzing the error due to the deviation of the actual signals from the harmonic model, used a technique based on the estimation of the error of the measurement result parameter as a function whose arguments are given with an accuracy of approximately corresponding to the deviation from the model of a real signal. An approach to the determination of PHS on the basis of comparison the input and additional voltages. This approach allowed the development of a method which, unlike most of the known methods based on the formation of additional signals, uses only one additional voltage and eliminates the possibility of the frequency error of phase shifting block. The implementation of this method uses only three analog-to-digital converters, which reduces the hardware cost. The obtained results allow to assess the error in determining the parameters at a deviation of the input signals from the harmonic model, as well as select the parameters of the measurement process in accordance with the requirements for accuracy.

signal parameters, harmonic model, the instantaneous values, additional signals, the phase-shifting block, an error, deviation of the actual signal from model.