Methods for Quick Measurement of Integral Parameters of a Periodic Signal

The article discusses the methods of rapid measurement of the integral characteristics of currents and voltages of high-power electrical equipment. Methods of online measurement of integral characteristics are considered to prevent emergency situations of such equipment. The foundation and practical methods implementation are given. The methods classification for measuring the effective value of voltage and current by the instantaneous values of a non-harmonic periodic signal during its one half period is determined. Factors classification influencing the choice of the method for determining the integral characteristics based on the formation of an additional signal is presented. Methods that determine the effective value of a signal by its values for a quarter of a period, as well as for one eighth of a period are proposed. A method that determines the effective value of a signal based on the average value of its instantaneous values is proposed. It is shown that at a certain phase of the third harmonic of a periodic signal, the errors of the considered methods are minimal. A method for determining the effective value of a signal by its integration over half the period is proposed. The errors of the proposed methods caused by the presence of the third harmonic of the analyzed signal are determined. The errors dependencies on the phase of the third harmonic signal are determined. The dependencies of the maximum value of these errors on the amplitude of the third harmonic of the signal being analyzed are also determined. It is shown that the dependence is linear. The systems structures that implement the described methods are given. It is proposed to use the described methods if it is necessary to determine quickly the effective value of a periodic non-harmonic signal (within no more than half of its period) with low accuracy requirements of the methods (about 10 … 20%). It has also been proposed to use the described methods when it is necessary to control power electrical equipment with rapid changes in its load, which is typical of electrical units of modern electric and hybrid vehicles, as well as energy-saving power units.