Alternating current signal effective value measuring device

Abstract

The invention provides an alternating current signal effective value measuring device which comprises an absolute value conversion circuit, a high-frequency triangular wave generation circuit, a PWM signal modulation circuit, a front-end integral circuit, a rear-end integral circuit, a reset circuit, a sampling maintaining circuit, a dividing circuit, a root circuit and a timing circuit. According to the alternating current signal effective value measuring device, the absolute value | v(t)/of signals to be tested v(t) and single-polarity symmetric high-frequency triangular wave signal v(t) are subjected to modulation, and high-frequency PWM signals far higher than the v(t) frequency are obtained; due to the fact that v(t) are continuous signals, and vc(t) frequency is far higher than v(t), the area of the PWM signals in each cycle is equal to the area formed by the| v(t)/in the corresponding PWM signal cycle; meanwhile, v(t)<2> is also a continuous function, so that the effective value of v(t) can be obtained by calculating the square and evolution of the PWM signals in the cycle T of v(t). According to the alternating current signal effective value measuring device, the alternating signals v(t) for calculating the effective value are all alternating cycle signals, namely alternating current cycle signals containing direct current components and alternating current components, so that the alternating current signal effective value measuring device can effectively solve the problem that the signal to be tested contains direct current components and harmonic waves and is wider in application range.

Description

technical field [0001] The invention belongs to the fields of instrumentation, signal processing and measurement and control, and in particular relates to an effective value measuring device of an AC signal, which is used for measuring the effective value of any AC periodic signal. Background technique [0002] The effective value measurement of AC periodic signal plays an important role in the fields of instrumentation, signal processing and measurement and control, and is an important part of electrical parameter measurement. At present, the commonly used AC periodic signal RMS measurement is mainly divided into two schemes: hardware measurement and software measurement. The hardware scheme measures the effective value of the AC periodic signal based on the average value of |v(t)| Calculate the effective value of AC periodic signal v(t) This is because for a sinusoidal AC signal: Therefore, the effective value can be calculated by measuring the average value. Howeve...

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Problems solved by technology

However, this method has the following disadvantages: ①The method is narrowly applicable and only suitable for sinusoidal signals; ②The sinusoidal signal cannot have a DC component; ③The sinusoidal signal cannot have harmonics

This method can measure the effective value of any periodic signal, but it has the following disadvantages: ① In order to ensure the accuracy, a high-speed processor must be used to realize high-speed sampling and high-speed calculation, so the processor has high requirements; ② When calculating the effective value V rms N times of multiplication, N times of addition, 1 division and 1 square root operation of floating-point numbers are required, which will occupy a large amount of CPU system memory and running time, especially in occasions with high real-time requirements.

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