Variable-rate four-quadrant multiplier for metering of electric energy meter

Abstract

The invention discloses a variable-rate four-quadrant multiplier for metering of an electric energy meter, and relates to the field of electric energy metering. A conventional four-quadrant multiplier needs an LPF filter to filter out a double fundamental component cos (2[omega]t), the filter has response time inevitably, and the LPF has narrow bandwidth and long response time relative to the sampling rate, so the dynamic metering effect is inevitably influenced. According to the invention, a conventional two-stage LPF filter is replaced by a whole-cycle accumulation averaging circuit, and an ADC sampling rate automatic adjusting circuit is added in a voltage input channel. A second-stage filter of a conventional electric energy metering four-quadrant multiplier is canceled, a whole cycle wave accumulation averaging circuit is adopted, and the average power of cycle waves is obtained through a method of accumulating the whole cycle waves and then averaging, so better metering dynamic response performance can be obtained; the ADC sampling rate is dynamically adjusted by measuring the number of sampling points of a single or multiple cyclic waves of the fundamental wave signal, and synchronous sampling is achieved.

Description

technical field [0001] The invention relates to the field of electric energy measurement, in particular to a variable-rate four-quadrant multiplier for electric energy meter measurement. Background technique [0002] Digital four-quadrant multipliers have been maturely used in many fields of science and technology. [0003] For existing single-phase electricity meters, a typical application of a four-quadrant multiplier is figure 1 As shown, in general, the three-channel ADC is used for live wire current input, voltage signal input, and neutral wire current input, and ADC2 is for voltage signal input. After being sampled by the ADC, the voltage and current signals are converted from analog to digital, and multiplied according to a fixed sampling rate to obtain power. The voltage and current signals will have related low-pass filters and / or high-pass filters and related correction currents , After the two digital signals are multiplied, there is a low-pass filter to filter ...

AI Technical Summary

Problems solved by technology

Since the filter must have a response time, and this LPF has a narrow bandwidth compared to the sampling rate, the response time will be relatively long, which will inevitably affect the dynamic measurement effect

The filter on the sampling loop), generally a comb decimation filter, can have a better dynamic response, while the LPF filter reduces the overall dynamic response performance. In order to improve the dynamic response performance of the entire system, it is necessary to solve the LPF filter The problem

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