SU789792A1 - Method of measuring sine voltage amplitude - Google Patents

Description

one

The invention relates to a measurement technique, namely to measuring the amplitude of an alternating voltage.

A known method of measuring a sinusoidal signal is measured, according to which the measured signal is rectified, and then the constant (or low-frequency) component of the measured signal is extracted using a filter. The amplitude of the sinusoidal voltage is judged by the magnitude of the signal proportional to this c1 amplitude 1.

The disadvantage of this method of measurement is low speed, since the process of filtering out the low-frequency (constant) component is an inertial process. To extract the desired signal, a time of approximately 8-10 periods of a sinusoidal signal is necessary.

There is also known a method for measuring the amplitude of a sinusoidal voltage based on sampling the instantaneous values of voltage 2.

This method is the closest to the technical essence and the achieved result of the present invention.

However, the accuracy and immunity of the known method is low.

The purpose of the invention is to improve the accuracy and interference; 1.

5 This goal is achieved by the fact that the measured signal is shifted in phase by 90, the values of the measured and shifted signals are determined at discrete points in time, the obtained values of the measured signal are determined.

multiplied by the sine, and the value of the shifted signal - by the cosine of the current discrete value of the phase shift, while the desired value

15 amplitudes are defined as the sum of these works.

Figure 1 shows the block diagram of the device, reshiznaya method; in fig. 2 - time diagrams of signals.

The device consists of a phase-shifting unit 1, pulse keys 2 and 3, KO MyTHpyeNMx with frequency f, memory elements 4 and 5, sine 25 6 and cosine 7 transducers, adder 8.

The device works as follows.

The measured voltage U is shifted by 90 ° by the phase shifter 1. At the moment of arrival of the pulse with frequency f | j, the pulse keys 2 and 3 shortly open, skipping the discrete values of the measured and shifted by 90 ° signals in memorizing elements 4 and 5. Pulses with a frequency ffc also commute sinus b and cosine 7 transducers, synchronized by the measured and quadrature to the measured voltages. The resulting voltage Uj is obtained at the output of the adder 8. As can be seen from FIG. 2 a and 5, the measured signal U |, UM sinCuJt + H is shifted in phase by 90 ° (j U), the values of each of these two signals are determined (the ordinates in Fig. 2 a and b are at discrete points in time (U, c .-. H viU40,), ZjTj. K is the multiplicity of the switching frequency f to the frequency f of the measured signal, i 1, 2, 3, ... The received values of the first signal are multiplied by the sine of the current disk phase value L, - .4 -4j -% (i-cos2 e +4). Values - the second signal multiplied by the cosine of the same phase 3. + Ch. |, Tcosaje +, I get the resulting value as the sum of these two products v, ..

Claims (2)

“I, r-i / e- f / t / tft f; Thus, the proposed method of measuring the amplitude of a sinusoidal voltage due to the described sequence of actions provides higher accuracy and noise immunity. In this case, it is not necessary to filter out the variable component, and the accuracy and noise immunity also increase due to the acquisition of information in a pulsed form. Claims The method of measuring sinusoidal voltage gilplits based on the discretization of instantaneous voltage values, characterized in that, for the purpose of higher-. Neither accuracy and noise immunity, measured SGS is shifted in phase by 90; In this case, the amplitude value sought is determined as the sum of these products. Sources of information taken into account in the examination 1. Apushkinsky G.V. Electrical and electronic circuits. L., LSU, 1972, p. 108 2. Gitis E.I. Information converters for electronic digital computing devices, M., Energie, 1975, p. 344-346. (" / n / UK / rrx  L / vj l 0 U V V "Ufft yjf" fei fj g n, “iJ a I // jr L / YAG "Ff eft % / Pch / y W kvi fM Jt / g a fne.