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Active power measurement method and system based on digital filtering

A technology of active power and digital filtering, which is applied in the direction of electric power measurement, measuring device, and electric power measurement through the application of digital technology, which can solve the problems of long time for filtering to stabilize, high performance requirements of DC filtering, and large intermediate signal ripple.

Inactive Publication Date: 2015-07-15
常州昊云工控科技有限公司
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Problems solved by technology

When this existing method measures the active power of a pure sinusoidal circuit or a sinusoidal circuit with less harmonics, the ripple of the intermediate signal is large, so the performance requirements for the DC filter are high, and the time for the filter to stabilize is long.

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  • Active power measurement method and system based on digital filtering
  • Active power measurement method and system based on digital filtering
  • Active power measurement method and system based on digital filtering

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Embodiment Construction

[0058] The principle block diagram of the embodiment of the present invention is as image 3 As shown, its system structure is as follows Figure 4 shown. refer to image 3 and Figure 4 , the working process of the present invention based on the active power measurement embodiment of digital phase-shift filtering is as follows:

[0059] Step 1: First, a pair of AC analog voltage signals measured from the 50Hz power frequency grid u ( t ) and AC analog current signali ( t ) according to the same fixed sampling frequency F s =2000Hz for analog-to-digital conversion to obtain discrete digital voltage signals and digital current signal . The signal frequency range of active power measurement is (40, 960) Hz, that is f 1 =40Hz, f 2 =960Hz. Sampling frequency F s satisfy F s >2× f 2 .

[0060] Step 2: The digital voltage signal obtained in the above step 1 Simultaneously through two sets of digital phase shift filters F 1 and F 2, the phase-shifted volta...

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Abstract

The invention relates to an active power measurement method and system based on digital filtering, and belongs to the field of electric power parameter measurement technology. The method is characterized in that: firstly, a pair of analog voltage and current signal is converted into a pair of digital voltage and current signal through a analog-digital conversion method; then, the digital voltage and the current signal are processed through four digital phase-shift filters so that a pair of phase-shift voltage signals and a pair of phase-shift current signals are obtained; and at last, performing arithmetic operations and DC filtering on the phase-shift voltage signals and the phase-shift current signals and active power data is measured. The system is characterized in that: the system is composed of analog-digital converters, the digital phase-shift filters, an arithmetic operation portion and a DC filter. According to the invention, digitalized measurement of the active power is realized; with the method, ripple of an intermediate signal is small, so that performance requirement of the DC filtering is low and measuring speed is fast; besides, if similar method is used in the active power and a reactive power together, the obtained active measurement results and inactive measurement results are coherent in time.

Description

technical field [0001] The invention relates to a method and system for measuring active power based on digital filtering, and belongs to the technical field of power parameter measurement. Background technique [0002] Active power is one of the important power parameters of the power system. Active power measurement is not only a necessary link to understand the user's electricity consumption status and accumulated electric energy, but also the only means for the power sector to achieve energy regulation and market operation. Fast and accurate measurement of active power has always been an important research topic in the field of power measurement. [0003] The principle of the active power measurement method widely used at present is as follows: figure 1 shown. This method is to convert a pair of voltage signal and current signal on the AC grid through analog-to-digital conversion to obtain a sampled digital voltage signal. u ( n ) and digital current signal i ( n ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R21/00G01R21/133
Inventor 庞浩
Owner 常州昊云工控科技有限公司