Small-signal power correcting circuit

Abstract

The invention discloses a small-signal power correcting circuit which comprises a small-signal correcting standard value obtaining circuit, a power coefficient calculating circuit, a correcting value calculating circuit, a power calculating circuit and a power correcting circuit. The small-signal correcting standard value obtaining circuit is used for obtaining and outputting a preset correcting standard value, the power coefficient calculating circuit is used for calculating to obtain and output the power coefficient, the correcting value calculating circuit is used for multiplying the received correcting standard value and the power coefficient to obtain a correcting value and outputting the correcting value, the power calculating circuit is used for calculating to obtain active power and reactive power and outputting the active power and the reactive power, and the power correcting circuit is used for adding the received active power, the received reactive power and the correcting value to obtain an after-correcting power value and outputting the after-correcting power value. According to the small-signal power correcting circuit, the input power is corrected through the correcting value correspondingly adjusted along with changes of the power coefficient, the correcting value is accurate, and the error of the finally-calculated power value is small.

Description

Technical field [0001] The present invention relates to the field of electric energy metering, in particular to a power (active power and reactive power) correction circuit. Background technique [0002] With the continuous deepening of energy conservation and environmental protection, the power of equipment connected to the grid is getting smaller and smaller. The measurement of low-power signals is more complicated than that of high-power signals. The same calculation method can be used to obtain the power of small signals, but it is comparable to large signals. Compared with the calculation, the relative error is relatively large. Therefore, when processing low-power signals, some special processing needs to be done to adapt to the characteristics of low-power signals. Using common power calculation methods to calculate power will inevitably produce errors. To obtain more accurate results, the direct calculation results must be corrected. The correction effects of different co...

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Problems solved by technology

[0003] In the existing electric energy metering system, the correction of power generally adopts fixed value correction, and the correction of active power and reactive power is not corrected according to the difference of power factor, so the error is large and the correction result is not accurate enough.

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