Resistor-capacitor decoupling soft sensing method based on magnitude-phase characteristics

Abstract

The invention relates to a resistor-capacitor decoupling soft sensing method based on magnitude-phase characteristics, belonging to the technical field of the soft sensing technology of solution conductivity. The method is characterized in that the conductivity measurement in a conductivity cell is changed to the measurement of electrical property equivalent resistance-capacitance network of the conductivity cell, and the magnitude-phase characteristics of the resistance-capacitance network is estimated to obtain the resistance-capacitance parameter, wherein the resistance parameter is the resistance of the solution to be measured. Sine wave is used to excite the resistance-capacitance network; the steepest descent method is adopted for optimization and calculation based on the non-linear principle of least square; and multi-sampling of response signals is utilized to fit system function form and further obtain magnitude-phase characteristic parameter of the system. Then the magnitude-phase characteristics and the function relationship of the resistance-capacitance network are used to obtain the resistance-capacitance parameter. The invention has the effects and benefits of higher measurement accuracy and less iterations. In addition, the invention also provides a method for accurately obtaining the magnitude-phase characteristics of the linear system.

Description

technical field [0001] The invention belongs to the technical field of solution conductivity soft measurement, and relates to a decoupling soft measurement method for equivalent resistance-capacitance network parameters of electrical characteristics of a conductance cell, in particular to a method for obtaining resistance-capacitance network parameters through amplitude and phase characteristic detection. Background technique [0002] As an important electrochemical analysis parameter, conductivity is widely used in production and scientific research departments such as chemical industry, metallurgy, biology, medicine, food and water conservancy. As the conductivity measurement is more and more widely used, the requirements for its measurement accuracy and measurement speed are also getting higher and higher. The methods mentioned in the literature [1] include phase-sensitive detection method, double pulse method and dynamic pulse method. These methods are based on the equiv...

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Problems solved by technology

The phase-sensitive detection method uses sinusoidal excitation to eliminate the polarization effect, and can effectively eliminate the influence of the distributed capacitance of the lead, but ignores the existence of the electric double layer capacitance

The double-pulse method uses two opposite-polarity pulse excitations, which takes into account the influence of the electric double layer capacitance and the distributed capacitance of the leads. It has great advantages in principle, but it requires extremely high time synchronization in implementation.

The dynamic pulse method uses the flow pulse as the excitation, which can effectively eliminate the capacitive effect, and at the same time reduce the influence of the polarization effect by reducing the pulse amplitude, but it is difficult to completely eliminate it

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