Method and system for measuring alternating voltages by applying multicycle strategy to digital-to-analogue conversion

Abstract

The invention provides a method and system for measuring alternating voltages by applying a multicycle strategy to digital-to-analogue conversion. The technology in an ADC is transferred into a DAC. According to the main principle, a cycle of step waves generated by the DAC is used for covering multiple cycles of measured sine waves. The method comprises the steps that S1, P cycles of measured sine voltage signals are equally divided into N parts, no common divisor exits between P and N except for 1, and the numerical value of step wave steps is generated; S2, the N pieces of data are input into the DAC to generate a cycle of step waves; S3, the plateau voltage value of the step waves is measured; S4, difference sampling is carried out on the two waveforms; S5, a segmented sampling mode is adopted during DFT operation, and only intermediate data of the steps is calculated. The method and system have the advantages that the measuring accuracy is improved, and measuring frequency can be extended.

Description

technical field [0001] The present invention relates to the technical field of AC voltage measurement, in particular to the most common sinusoidal voltage signal measurement method and system thereof, and the related measurement technical field. Background technique [0002] The invention is a new development on the basis of step wave measurement of alternating current. The main principle of step wave measurement of alternating current is to use the step wave as the standard, and determine the parameters of the sine wave, such as amplitude and effective value, by measuring the difference between the step wave and the sine wave. The step wave originates from DC, which is a new type of AC-DC conversion principle in principle. In this measurement, the sampling points located on both sides of the staircase wave are discarded due to the existence of the transition process. So this method is called fragment sampling method. If the difference is controlled at the level of 1%, th...

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Problems solved by technology

DAC devices do not want frequent conversions, and frequent conversions sometimes cause problems. For example, the programmable quantum voltage reference will produce a "magnetic freeze" phenomenon.

On the other hand, in order to obtain accurate measurement results, the more subpoints in a sine wave cycle, the better, which requires more steps for the step wave, so the steps cannot be very wide; especially when the frequency of the measurement signal is relatively high When high, it will inhibit the step width

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