Electrostatic interference preventing capacitance measuring circuit and method

Abstract

The invention discloses electrostatic interference preventing capacitance measuring circuit and method. The measuring circuit comprises a first signal generator, a second signal generator, a capacitance and voltage conversion module, a band-pass filter, a signal amplifier, an analog multiplier and a low-pass filter; the capacitance and voltage conversion module comprises a capacitance sensor, and a converting module for converting the capacitance detected by the capacitance sensor into voltage; the first signal generator is connected with an exciting electrode of the capacitance sensor; the band-pass filter, the signal amplifier, the analog multiplier and the low-pass filter are sequentially connected in series with the output end of the conversion module; the second signal generator is connected to another signal input port of the analog multiplier; an output signal of the second signal generator has the same frequency with the output siganl of the first signal generator, and the phase difference of the two output signals is zero. Compared with the prior art, the circuit has the advantages that the problem of particle charge interference during charge injection, zero drifting and air and solid flowing as the measuring objects can be overcome, and therefore, measurement deviation can be avoided.

Description

technical field [0001] The invention relates to a capacitance measuring circuit, in particular to a measuring circuit and a measuring method capable of preventing electrostatic interference. Background technique [0002] Two-phase flow systems widely exist in industrial fields such as energy, chemical industry, electric power and metallurgy. With the development of modern industry, the requirements for the detection and control of industrial process parameters are getting higher and higher. Accurate measurement of two-phase flow parameters has important practical significance for the safe and efficient operation of industrial processes and environmental protection. The capacitance method has the advantages of non-contact, high reliability and low cost, and has been successfully used in the phase concentration measurement of two-phase flow or multiphase flow. The basic principle is that when the fluid passes through the sensitive electric field formed by the capacitance plate...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a method to prevent electrostatic interference and improve measurement reliability and accuracy in view of the problem that the measurement results are affected by the charge of particles when the existing capacitance method is used to measure the particle phase concentration of gas-solid two-phase flow. Capacitance measurement circuit and measurement method

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