A Method of Sampling and Measuring AC RMS

An AC RMS and RMS technology, applied in the direction of using digital measurement technology for measurement, can solve the problems of difficulty in improving accuracy, slow response speed, and inability to analyze the RMS value of signal harmonic components, to improve accuracy, Resolve the effect of different amplitude attenuation

Inactive Publication Date: 2017-09-05
SHANGHAI INST OF MEASUREMENT & TESTING TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] The disadvantage of the first method is that the response speed is slow, the measured result is the total effective value of AC, and the effective value of each harmonic component in the signal cannot be analyzed
[0012] The second method can get the effective value of the AC signal, but if the AC signal is a broadband signal, the result is limited by the A / D converter and the accuracy is difficult to improve

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  • A Method of Sampling and Measuring AC RMS
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  • A Method of Sampling and Measuring AC RMS

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Embodiment Construction

[0038] The present invention will be described in detail below in terms of specific embodiments in conjunction with the accompanying drawings. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It is to be noted that other embodiments may be utilized or structural and functional modifications may be made to the embodiments set forth herein without departing from the scope and spirit of the present invention.

[0039] 1. Aperture time of the sample-and-hold (SHA)

[0040] Such as figure 1 As shown, in the present invention, the aperture time Δt of the sample-and-hold (SHA) is the time interval for the sample-and-hold switch K to change from low impedance to high impedance. During the aperture time, the voltage on the holding capacitor continues to follow the input signal f(t), and at the end of the aperture time, the actual voltage on the holding capacitor f'(t+Δt) depends ...

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Abstract

The invention provides a method for sampling and measuring AC effective values, comprising: step 1, calculating the first amplitude value of each frequency component according to the A / D sampling of the AC signal to be measured to obtain the sampling data; step 2, calculating the first amplitude value of each frequency component Compensate the first amplitude value of each frequency component to obtain the second amplitude value of each frequency component; step 3, obtain the total effective value of the AC signal to be measured and the total effective value of AC and DC according to the second amplitude value of each frequency component. The invention calculates the amplitude of each frequency component through A / D sampling data, and then compensates the amplitude of each frequency component respectively, so as to improve the measurement accuracy of the amplitude of each frequency component. According to the magnitude of each frequency component, the total effective value is calculated by the root mean square method. The method effectively solves the different amplitude attenuation of different frequency signals caused by the inevitable aperture time of the A / D converter in the existing method. It can be used in precision measurement of AC RMS and harmonic analysis.

Description

technical field [0001] The invention relates to a measurement method, in particular to a method for sampling and measuring the effective value of alternating current. Background technique [0002] At present, there are two methods for measuring the effective value of alternating current. [0003] The first common method is to use the thermoelectric equivalent conversion principle to convert alternating current into direct current through a thermoelectric converter. The amplitude of the measured direct current is the effective value of alternating current. Several patents involved in this method are listed below: [0004] A true RMS AC voltmeter disclosed in the utility model patent 201320195662.X filed by Chengdu Master Mobile Information Technology Co., Ltd. on April 18, 2013. [0005] Patent 87209290 filed by Shen Yufeng on June 20, 1987 discloses a multifunctional true RMS voltmeter. [0006] The patent 201010170561.8 filed by Miao Gengping on May 12, 2010 discloses a...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): G01R19/25
Inventor石雷兵来磊周碧红冯建韩志强江习
OwnerSHANGHAI INST OF MEASUREMENT & TESTING TECH