A permanent magnet excitation polarization suppression system for electromagnetic water meters based on PID control

Abstract

The present invention relates to the field of fluid measurement and intelligent metering technology, and discloses a permanent magnet excitation polarization suppression system for electromagnetic water meters based on PID control. The system comprises: an initialization and parameter configuration module for setting the permanent magnet reference magnetic induction intensity, perturbation magnetic deviation amplitude, PID controller parameters, Kalman filter noise parameters, and flow calibration coefficient; a hybrid magnetic field generation module for generating a DC superimposed sine hybrid magnetic field; a synchronous sampling and polarization estimation module for estimating polarization in real time using a Kalman filter algorithm; a polarization compensation and flow signal separation module for extracting a pure flow signal through voltage compensation; a closed-loop perturbation adjustment module for calculating and updating the perturbation magnetic deviation amplitude; and a flow calculation and output module for multiplying the flow signal voltage by the flow calibration coefficient to output the final flow value. The present invention achieves low-power, high-precision, real-time polarization suppression and flow measurement.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid measurement and intelligent metering, and in particular relates to a permanent magnet excitation polarization suppression system for an electromagnetic water meter based on PID control. Background Art

[0002] Electromagnetic water meters are widely used in industrial and residential water supply and drainage applications due to their high precision, lack of moving parts, and corrosion resistance. Traditional electromagnetic water meters often use electromagnetic excitation, which requires a continuous power supply to generate a stable magnetic field in the measuring pipe. This increases energy consumption and system complexity. To reduce power consumption, some technicians have used permanent magnets for excitation. This method generates a DC magnetic field, eliminating the need for continuous power supply, but this introduces the problem of electrode polarization.

[0003] Electrode polarization occurs when a fluid undergoes an electrochemical reaction or capacitive effect at the electrode interface under the influence of a permanent magnetic field, generating a slowly accumulating quasi-DC potential. This polarization potential, combined with the flow rate signal, not only weakens the dynamic response of electromagnetic induction but also causes slow drift due to factors such as temperature fluctuations and water impurities. Traditional DC filtering or timed zeroing compensation methods struggle to achieve real-time and thorough polarization suppression while maintaining low power consumption. This leads to increased measurement errors, delayed responses, and even compromises to long-term stable operation.

[0004] In the existing technology, low-pass filtering, integral correction or bipolar excitation are often used to suppress polarization. However, these methods may require additional power supply, or have insufficient response to transient changes, or increase the complexity of the system structure. They are not suitable for online water meter monitoring with high requirements on power consumption and real-time performance. Summary of the Invention

[0005] The present invention provides a permanent magnet excitation polarization suppression system for electromagnetic water meters based on PID control, which solves the technical problems in the related art that permanent magnet excitation electromagnetic water meters have decreased measurement accuracy due to electrode polarization, and that existing suppression methods have high power consumption, delayed response, and incomplete suppression.

[0006] The present invention provides a permanent magnet excitation polarization suppression system for an electromagnetic water meter based on PID control, comprising:

[0007] Initialization and parameter configuration module, used to set the permanent magnet reference magnetic induction intensity, perturbation magnetic deviation amplitude, PID controller parameters, Kalman filter noise parameters and flow calibration coefficient;

[0008] A hybrid magnetic field generation module is used to generate a reference DC magnetic field through a permanent magnet based on the reference magnetic induction intensity of the permanent magnet and the perturbation magnetic bias amplitude, and to output a hybrid magnetic field by superimposing a sinusoidal perturbation magnetic bias through a perturbation coil;

[0009] A synchronous sampling and polarization estimation module is used to synchronously collect the original mixed signal voltage of the flow electrode and the pure polarization voltage of the reference electrode under the action of the mixed magnetic field, and to perform online estimation of the reference polarization voltage based on the Kalman filter algorithm to obtain the predicted polarization value;

[0010] Polarization compensation and flow signal separation module, used to subtract the predicted polarization value from the original mixed signal voltage obtained by synchronous sampling to obtain the flow signal voltage;

[0011] The closed-loop perturbation adjustment module is used to calculate the perturbation magnetic deviation amplitude correction value by using the predicted polarization as the error input and combining it with the PID controller parameters. It updates the perturbation magnetic deviation amplitude and imposes upper and lower limit constraints on the perturbation magnetic deviation amplitude.

[0012] The flow calculation and output module is used to multiply the flow signal voltage by the flow calibration coefficient and output the final flow value.

[0013] Furthermore, the PID controller parameters set by the initialization and parameter configuration module include a proportional coefficient, an integral coefficient, and a differential coefficient, which are used by the closed-loop perturbation adjustment module to calculate a perturbation magnetic deviation amplitude correction value;

[0014] The Kalman filter noise parameters set by the initialization and parameter configuration module include a process noise covariance matrix and an observation noise covariance matrix, which are used for the synchronous sampling and polarization estimation module to perform Kalman filter online estimation;

[0015] The perturbation magnetic bias amplitude set by the initialization and parameter configuration module is calculated by multiplying a preset perturbation initial amplitude ratio by the permanent magnet reference magnetic induction intensity, and is input into the hybrid magnetic field generation module as an initial value;

[0016] The flow calibration coefficient set by the initialization and parameter configuration module is determined by the ratio of the preset standard flow and the corresponding flow signal voltage, and is used by the flow calculation and output module to calculate the final flow value.

[0017] Furthermore, the hybrid magnetic field generation module generates a hybrid magnetic field composed of a constant magnetic field component and a sinusoidal perturbation magnetic field component superimposed on the permanent magnet reference magnetic induction intensity and the perturbation magnetic bias amplitude set by the initialization and parameter configuration module; wherein the constant magnetic field component is generated by the permanent magnet, and the sinusoidal perturbation magnetic field component is generated by the perturbation coil, and its frequency adopts a preset perturbation magnetic bias frequency;

[0018] The synchronous sampling and polarization estimation module performs dual-electrode signal acquisition under the action of the hybrid magnetic field output by the hybrid magnetic field generation module;

[0019] The closed-loop perturbation adjustment module uses the predicted polarization output by the synchronous sampling and polarization estimation module as an error input, calculates the perturbation magnetic bias amplitude correction amount to update the perturbation magnetic bias amplitude, and feeds the updated perturbation magnetic bias amplitude back to the hybrid magnetic field generation module to form a closed-loop adjustment.

[0020] Furthermore, a Kalman filter algorithm is used to generate a predicted polarization value according to a prediction update process based on process noise covariance and measurement noise covariance. The prediction update process includes: state prediction, Kalman gain calculation, state update and covariance update.

[0021] Furthermore, the closed-loop perturbation adjustment module further includes:

[0022] an error calculation unit, configured to use the predicted polarization value output by the synchronous sampling and polarization estimation module as a current polarization error;

[0023] An integral and differential operation unit, used to calculate error accumulation and error change rate according to a preset sampling period;

[0024] PID calculation unit, used to calculate the perturbation magnetic deviation amplitude correction value based on the current polarization error, error accumulation, error change rate and PID controller parameters;

[0025] The amplitude updating unit is used to subtract the perturbation magnetic bias amplitude correction amount from the perturbation magnetic bias amplitude at the previous sampling moment to obtain an updated perturbation magnetic bias amplitude, and constrain the updated perturbation magnetic bias amplitude to be within a preset amplitude range.

[0026] Furthermore, the error accumulation is obtained by multiplying the current polarization error by a preset sampling period and adding the result to the error accumulation at the previous sampling moment; and the error change rate is obtained by dividing the difference between the current polarization error and the polarization error at the previous sampling moment by the preset sampling period.

[0027] Furthermore, the perturbation magnetic bias amplitude correction amount is obtained by adding the product of the proportional coefficient and the current polarization error, the product of the integral coefficient and the error accumulation, and the product of the differential coefficient and the error change rate.

[0028] Furthermore, the perturbation magnetic deviation amplitude after each update is recorded, and when the change in the perturbation magnetic deviation amplitude exceeds a first preset threshold, an alarm signal is output.

[0029] Furthermore, when it is monitored that the final flow value is 0 within the first preset time period, the perturbation coil drive is switched to the energy-saving mode.

[0030] The beneficial effects of the present invention are as follows: the present invention introduces permanent magnets to generate a reference magnetic field, so that long-term stable operation can be achieved without continuous power supply, thereby significantly reducing energy consumption; at the same time, combined with the perturbation magnetic bias modulation technology, the flow signal is decoupled from the electrode polarization potential in the frequency domain, effectively suppressing quasi-DC interference; with the help of Kalman filtering, real-time estimation of the polarization amount is achieved, and then the perturbation amplitude is dynamically adjusted through PID closed-loop control to achieve accurate and rapid polarization suppression; in addition, the present invention also has abnormality monitoring and energy-saving mode switching functions, and can autonomously enter low-power mode according to the flow status, further improving energy utilization efficiency; overall, the present invention is innovative and practical in terms of polarization suppression capability, measurement stability and system energy efficiency, and is suitable for water resource monitoring scenarios with high requirements on power consumption, accuracy and response. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a module schematic diagram of a permanent magnet excitation polarization suppression system of an electromagnetic water meter based on PID control of the present invention. DETAILED DESCRIPTION

[0032] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples.

[0033] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in one or more embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0034] like Figure 1 As shown, a permanent magnet excitation polarization suppression system for an electromagnetic water meter based on PID control includes:

[0035] Initialization and parameter configuration module, used to set the permanent magnet reference magnetic induction intensity, perturbation magnetic deviation amplitude, PID controller parameters, Kalman filter noise parameters and flow calibration coefficient;

[0036] A hybrid magnetic field generation module is used to generate a reference DC magnetic field through a permanent magnet based on the reference magnetic induction intensity of the permanent magnet and the perturbation magnetic bias amplitude, and to output a hybrid magnetic field by superimposing a sinusoidal perturbation magnetic bias through a perturbation coil;

[0037] A synchronous sampling and polarization estimation module is used to synchronously collect the original mixed signal voltage of the flow electrode and the pure polarization voltage of the reference electrode under the action of the mixed magnetic field, and to perform online estimation of the reference polarization voltage based on the Kalman filter algorithm to obtain the predicted polarization value;

[0038] Polarization compensation and flow signal separation module, used to subtract the predicted polarization value from the original mixed signal voltage obtained by synchronous sampling to obtain the flow signal voltage;

[0039] The closed-loop perturbation adjustment module is used to calculate the perturbation magnetic deviation amplitude correction value by using the predicted polarization as the error input and combining it with the PID controller parameters. It updates the perturbation magnetic deviation amplitude and imposes upper and lower limit constraints on the perturbation magnetic deviation amplitude.

[0040] The flow calculation and output module is used to multiply the flow signal voltage by the flow calibration coefficient and output the final flow value.

[0041] In one embodiment of the present invention, the initialization and parameter configuration module is used to read and set key parameters required for subsequent operation of this embodiment at one time, and load them into the controller to ensure stable operation of each functional module.

[0042] The permanent magnet reference magnetic induction intensity represents the constant DC magnetic field intensity generated by the permanent magnet;

[0043] The PID controller parameters include: proportional coefficient, integral coefficient, and differential coefficient. The proportional coefficient is used to amplify the current polarization error to achieve immediate response to the error; the integral coefficient is used to feed back the cumulative effect of the error over time into the regulation variable, thereby eliminating the system's steady-state error; and the differential coefficient is used to suppress system overshoot caused by a rapid error change rate and provide damping by predicting the error trend. The three coefficients work together to determine the response speed, stability, and overshoot amplitude of the closed-loop perturbation control module to the polarization bias.

[0044] The Kalman filter noise parameters include: a process noise covariance matrix and an observation noise covariance matrix; wherein the process noise covariance matrix represents the uncertainty assessment of the polarization quantity state model; the larger its value, the lower the filter's trust in the model prediction and the higher its dependence on the measured value; the measurement noise covariance matrix represents the uncertainty assessment of the reference electrode sampling noise; the larger its value, the higher the filter's dependence on the model prediction results when updating the state; by reasonably setting the process noise covariance matrix and the observation noise covariance matrix, the Kalman filter can achieve a dynamic balance between the prediction and update stages and track the slow drift of the polarization potential in real time.

[0045] The perturbation magnetic bias amplitude is calculated by multiplying a preset perturbation initial amplitude ratio and the permanent magnet reference magnetic induction intensity, wherein the perturbation initial amplitude ratio is a dimensionless proportional coefficient used to determine the magnitude of the AC magnetic bias initially applied to the perturbation coil relative to the DC reference field; preferably, the perturbation initial amplitude ratio is set to 5%; this setting can ensure that the AC perturbation is sufficient to move the flow signal to the predetermined frequency band, while avoiding excessive interference with the reference magnetic field.

[0046] The flow calibration coefficient is obtained by calculating the ratio of a preset standard flow rate and a corresponding voltage; the flow calibration coefficient is obtained through experimental calibration, that is, taking a plurality of preset standard flow rates and corresponding flow electrode output voltages and calculating the ratio between the two; the flow calibration coefficient linearly maps the pure flow signal voltage subsequently separated from the original voltage signal to the actual flow value, so that the system output meets the cubic meters / hour required for engineering applications.

[0047] In one embodiment of the present invention, the main function of the hybrid magnetic field generation module is to superimpose a sinusoidal AC magnetic bias with adjustable amplitude on the reference DC magnetic field generated by the permanent magnet to form a frequency-domain decoupled hybrid magnetic field, providing excitation and modulation signals for subsequent flow measurement and polarization suppression.

[0048] The hybrid magnetic field generation module includes: a permanent magnet excitation unit, a perturbation coil drive unit, and a signal control and switching unit. The permanent magnet excitation unit is used to measure the DC magnetic field with constant intensity generated inside the permanent magnet. The perturbation coil drive unit includes three parts: a sine wave signal generator, a current amplifier, and a perturbation coil, which perturbs the reference DC magnetic field. The signal control and switching unit is used to receive the updated perturbation magnetic deviation amplitude from the closed-loop perturbation adjustment module and adjust the output amplitude of the sine wave signal generator accordingly, so that the perturbation magnetic deviation amplitude actually generated by the perturbation coil is synchronized with the updated value.

[0049] At the beginning of each sampling period, the signal control and switching unit sets the amplitude of the sine wave signal generator according to the current perturbation magnetic deviation amplitude correction value; the sine wave signal is at a frequency of The perturbation coil is driven by a current amplifier so that an AC component is superimposed on the original DC magnetic field; ultimately, a mixed magnetic field is formed in the permanent magnet; wherein the mixed magnetic field generation module generates a mixed magnetic field composed of a constant magnetic field component and a sinusoidal perturbation magnetic field component superimposed based on the permanent magnet reference magnetic induction intensity and the perturbation magnetic bias amplitude set by the initialization and parameter configuration module; wherein the constant magnetic field component is generated by the permanent magnet, and the sinusoidal perturbation magnetic field component is generated by the perturbation coil, and its frequency adopts a preset perturbation magnetic bias frequency and is set to 200 Hz;

[0050] The synchronous sampling and polarization estimation module performs dual-electrode signal acquisition under the action of the hybrid magnetic field output by the hybrid magnetic field generation module;

[0051] The closed-loop perturbation adjustment module uses the predicted polarization output by the synchronous sampling and polarization estimation module as an error input, calculates the perturbation magnetic bias amplitude correction amount to update the perturbation magnetic bias amplitude, and feeds the updated perturbation magnetic bias amplitude back to the hybrid magnetic field generation module to form a closed-loop adjustment. When applied specifically, the hybrid magnetic field satisfies the formula:

[0052] ;

[0053] in, represents the magnetic field intensity generated by the mixed magnetic field at the kth sampling moment, It represents the reference magnetic induction intensity of the permanent magnet, which is determined by the permanent magnet's inherent material and structure, and provides a constant DC excitation field. represents the perturbation magnetic deflection amplitude at the kth sampling moment, k represents the sampling moment index, represents the preset perturbation magnetic bias frequency, preferably, Set to 200Hz, Indicates the time of the kth sampling moment.

[0054] The magnetic field strength of this formula is formed by the superposition of the permanent magnet reference magnetic induction intensity and the sinusoidal AC component. The permanent magnet reference magnetic induction intensity ensures that the scale constant of the electromagnetic water meter is stable and does not drift over time. The sinusoidal AC component modulates the real flow signal to a frequency Nearby, it is naturally separated from the quasi-DC polarization potential in the frequency domain, which is convenient for post-stage filtering and compensation; this superposition method takes into account both measurement accuracy and energy consumption optimization. The DC field is maintained by the permanent magnet with zero power consumption, and the AC perturbation can generate the required magnetic bias by passing a small current through the perturbation coil.

[0055] In one embodiment of the present invention, the synchronous sampling and polarization estimation module utilizes a dual-electrode structure to simultaneously acquire two voltage signals under a mixed magnetic field: one representing the raw mixed signal voltage from the flow electrode and the other representing the pure polarization voltage from the reference electrode. To accurately compare the two signals and perform polarization suppression, sampling of the flow electrode and the reference electrode must be triggered simultaneously at the same sampling moment. This synchronous sampling eliminates phase drift caused by channel delay differences, ensuring the accuracy of subsequent polarization estimation and compensation.

[0056] In one embodiment of the present invention, a Kalman filter algorithm is used to generate a predicted polarization quantity based on the process noise covariance and the measurement noise covariance according to a prediction update process. The predicted polarization quantity represents the optimal estimate of the current polarization potential. The prediction update process includes: state prediction, Kalman gain calculation, state update and covariance update; wherein, the posterior estimate at the previous moment is used as the prior state, and the prediction error covariance is updated in combination with the process noise covariance; the Kalman gain is calculated according to the prediction error covariance and the measurement noise covariance; the prior state is weighted and corrected by the difference between the measured value and the prior prediction value; and the posterior error covariance is corrected according to the Kalman gain.

[0057] In one embodiment of the present invention, the closed-loop perturbation adjustment module further includes:

[0058] an error calculation unit, configured to use the predicted polarization value output by the synchronous sampling and polarization estimation module as a current polarization error, where the current polarization error is used to reflect the residual polarization bias;

[0059] An integral and differential operation unit, used to calculate error accumulation and error change rate according to a preset sampling period;

[0060] A PID calculation unit is used to calculate a perturbation magnetic deviation amplitude correction value based on the current polarization error, error accumulation, error change rate, and PID controller parameters. Among the PID controller parameters, the proportional coefficient determines the direct response strength of the current polarization error to the correction value, the integral coefficient determines the compensation amplitude of the error accumulation to the correction value, and the differential coefficient determines the inhibitory effect of the error change rate on the correction value to prevent excessive oscillation.

[0061] The amplitude updating unit is used to subtract the perturbation magnetic deviation amplitude correction amount from the perturbation magnetic deviation amplitude at the previous sampling moment to obtain the updated perturbation magnetic deviation amplitude, and constrain the updated perturbation magnetic deviation amplitude to be within the preset amplitude range. That is, when the updated perturbation magnetic deviation amplitude exceeds the preset amplitude range, it is replaced with the corresponding upper and lower limits of the preset amplitude range.

[0062] In one embodiment of the present invention, the error accumulation is obtained by multiplying the current polarization error by a preset sampling period and adding the result to the error accumulation at the previous sampling moment; the error change rate is obtained by dividing the difference between the current polarization error and the polarization error at the previous sampling moment by the preset sampling period;

[0063] Specifically, the calculation formula for error accumulation is: ,in, represents the cumulative error at the kth sampling moment, represents the cumulative error at the k-1th sampling moment, represents the polarization error at the kth sampling moment, Indicates the preset sampling period;

[0064] The formula for calculating the error change rate is: ,in, represents the error change rate at the kth sampling moment, represents the polarization error at the k-1th sampling moment.

[0065] In one embodiment of the present invention, the perturbation magnetic bias amplitude correction amount is obtained by adding the product of the proportional coefficient and the current polarization error, the product of the integral coefficient and the error accumulation, and the product of the differential coefficient and the error change rate;

[0066] Specifically, the calculation formula for the perturbation magnetic bias amplitude correction is:

[0067] ,in, represents the perturbation magnetic deviation amplitude correction at the kth sampling moment, represents the proportionality coefficient, represents the integral coefficient, Represents the differential coefficient; when the proportional coefficient increases, the ratio term Also increases, so that the perturbation magnetic bias amplitude correction amount increases to quickly offset the sudden polarization bias; when the polarization error exists for a long time and is not completely eliminated, the integral term Gradually increase to eliminate steady-state errors and ensure that the system will eventually converge the polarization to zero; when the polarization error changes dramatically, the differential term It provides a damping effect, suppresses system overshoot and improves closed-loop stability. By adding the ratio term, integral term and differential term, the PID calculation unit of this embodiment can effectively suppress overshoot and eliminate steady-state errors while ensuring fast response, providing core algorithm support for continuous and accurate polarization suppression.

[0068] In one embodiment of the present invention, the flow calculation and output module is used to multiply the pure flow signal voltage obtained after polarization compensation by a pre-calibrated flow calibration coefficient to generate a final flow value that can be directly used for engineering monitoring; specifically, the pure flow signal voltage is output by the polarization compensation and flow signal separation module, representing an AC voltage signal containing only fluid flow rate information, in volts, and the final flow value represents the final instantaneous actual flow; the final flow value is cached and output via a communication interface or a local display unit, and can be used for meter reading records, remote monitoring or further water consumption analysis, and can simultaneously trigger data collection or alarm logic of the upper-level system, supporting multiple networking and storage methods.

[0069] In one embodiment of the present invention, in order to prevent abnormal fluctuations in the polarization suppression process from affecting the stability of the system, a perturbation magnetic deviation amplitude monitoring and alarm module is specially provided to record the perturbation magnetic deviation amplitude updated after each closed-loop adjustment, and to promptly output an alarm signal when the change in the amplitude exceeds a first preset threshold value to ensure the safe operation of the equipment and the medium; through real-time monitoring of the perturbation magnetic deviation amplitude and threshold alarm, the present invention can promptly detect abnormal jitter or algorithm instability in the control link; reduce the impact of damage on the internal magnetic circuit and collection electrodes of the water meter; improve reliability, and have automatic early warning capabilities for sudden failures during long-term operation.

[0070] In one embodiment of the present invention, in order to further reduce the power consumption of the system, when the system detects that the final flow value is continuously zero within the first preset time period, it is considered that there is no flow in the pipeline, and the perturbation coil drive is switched to the energy-saving mode; in the energy-saving mode, the perturbation coil can adopt any of the following strategies: reducing the driving current to the minimum holding value, periodically waking up for sampling, or completely powering off and standing by, so as to significantly reduce the overall energy consumption of the system; through this measure, the energy-saving mode switching function of the present invention can dynamically respond to changes in pipeline working conditions while ensuring measurement accuracy, and achieve energy saving during the long standby period without flow, thereby extending the service life of the water meter and its driving components and reducing operation and maintenance costs.

[0071] It should be noted that the intervals and thresholds are set for ease of comparison. The threshold size depends on the amount of sample data and the cardinality set by those skilled in the art for each set of sample data, as long as it does not affect the proportional relationship between the parameter and the quantized value. Furthermore, the above formulas are all dimensionless numerical calculations. These formulas are derived from software simulations of the most recent real-world conditions using large amounts of data. The preset parameters in these formulas are set by those skilled in the art based on actual conditions.

[0072] The above describes the embodiments of the present invention, but the present invention is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. A permanent magnet excitation polarization suppression system for electromagnetic water meters based on PID control, characterized in that: include: Initialization and parameter configuration module, used to set the permanent magnet reference magnetic induction intensity, perturbation magnetic deviation amplitude, PID controller parameters, Kalman filter noise parameters and flow calibration coefficient; A hybrid magnetic field generation module is used to generate a reference DC magnetic field through a permanent magnet based on the reference magnetic induction intensity of the permanent magnet and the perturbation magnetic bias amplitude, and to output a hybrid magnetic field by superimposing a sinusoidal perturbation magnetic bias through a perturbation coil; A synchronous sampling and polarization estimation module is used to synchronously collect the original mixed signal voltage of the flow electrode and the pure polarization voltage of the reference electrode under the action of the mixed magnetic field, and to perform online estimation of the reference polarization voltage based on the Kalman filter algorithm to obtain the predicted polarization value; Polarization compensation and flow signal separation module, used to subtract the predicted polarization value from the original mixed signal voltage obtained by synchronous sampling to obtain the flow signal voltage; The closed-loop perturbation adjustment module is used to calculate the perturbation magnetic deviation amplitude correction value by using the predicted polarization as the error input and combining it with the PID controller parameters. It updates the perturbation magnetic deviation amplitude and imposes upper and lower limit constraints on the perturbation magnetic deviation amplitude. The flow calculation and output module is used to multiply the flow signal voltage by the flow calibration coefficient and output the final flow value.

2. The PID-controlled permanent magnet excitation polarization suppression system for electromagnetic water meters according to claim 1 is characterized in that: The PID controller parameters set by the initialization and parameter configuration module include proportional coefficient, integral coefficient and differential coefficient, which are used for the closed-loop perturbation adjustment module to calculate the perturbation magnetic deviation amplitude correction value; The Kalman filter noise parameters set by the initialization and parameter configuration module include a process noise covariance matrix and an observation noise covariance matrix, which are used for the synchronous sampling and polarization estimation module to perform Kalman filter online estimation; The perturbation magnetic bias amplitude set by the initialization and parameter configuration module is calculated by multiplying a preset perturbation initial amplitude ratio by the permanent magnet reference magnetic induction intensity, and is input into the hybrid magnetic field generation module as an initial value; The flow calibration coefficient set by the initialization and parameter configuration module is determined by the ratio of the preset standard flow and the corresponding flow signal voltage, and is used by the flow calculation and output module to calculate the final flow value.

3. The electromagnetic water meter permanent magnet excitation polarization suppression system based on PID control according to claim 1 is characterized in that: The hybrid magnetic field generation module generates a hybrid magnetic field composed of a constant magnetic field component and a sinusoidal perturbation magnetic field component superimposed on the permanent magnet reference magnetic induction intensity and the perturbation magnetic bias amplitude set by the initialization and parameter configuration module; wherein the constant magnetic field component is generated by the permanent magnet, and the sinusoidal perturbation magnetic field component is generated by the perturbation coil, and its frequency adopts a preset perturbation magnetic bias frequency; The synchronous sampling and polarization estimation module performs dual-electrode signal acquisition under the action of the hybrid magnetic field output by the hybrid magnetic field generation module; The closed-loop perturbation adjustment module uses the predicted polarization output by the synchronous sampling and polarization estimation module as an error input, calculates the perturbation magnetic bias amplitude correction amount to update the perturbation magnetic bias amplitude, and feeds the updated perturbation magnetic bias amplitude back to the hybrid magnetic field generation module to form a closed-loop adjustment.

4. The PID-controlled permanent magnet excitation polarization suppression system for electromagnetic water meters according to claim 1 is characterized in that: A Kalman filter algorithm is used to generate a predicted polarization value according to a prediction update process based on process noise covariance and measurement noise covariance. The prediction update process includes: state prediction, Kalman gain calculation, state update and covariance update.

5. The PID-controlled permanent magnet excitation polarization suppression system for electromagnetic water meters according to claim 4 is characterized in that: The closed-loop perturbation regulation module further includes: an error calculation unit, configured to use the predicted polarization value output by the synchronous sampling and polarization estimation module as a current polarization error; An integral and differential operation unit, used to calculate error accumulation and error change rate according to a preset sampling period; PID calculation unit, used to calculate the perturbation magnetic deviation amplitude correction value based on the current polarization error, error accumulation, error change rate and PID controller parameters; The amplitude updating unit is used to subtract the perturbation magnetic bias amplitude correction amount from the perturbation magnetic bias amplitude at the previous sampling moment to obtain an updated perturbation magnetic bias amplitude, and constrain the updated perturbation magnetic bias amplitude to be within a preset amplitude range.

6. The electromagnetic water meter permanent magnet excitation polarization suppression system based on PID control according to claim 5 is characterized in that: The error accumulation is obtained by multiplying the current polarization error by a preset sampling period and adding the result to the error accumulation at the previous sampling moment; the error change rate is obtained by dividing the difference between the current polarization error and the polarization error at the previous sampling moment by the preset sampling period.

7. The electromagnetic water meter permanent magnet excitation polarization suppression system based on PID control according to claim 5 is characterized in that: The perturbation magnetic bias amplitude correction amount is obtained by adding the product of the proportional coefficient and the current polarization error, the product of the integral coefficient and the error accumulation, and the product of the differential coefficient and the error change rate.

8. The electromagnetic water meter permanent magnet excitation polarization suppression system based on PID control according to claim 5 is characterized in that: The perturbation magnetic deviation amplitude after each update is recorded, and when the change in the perturbation magnetic deviation amplitude exceeds a first preset threshold, an alarm signal is output.

9. The electromagnetic water meter permanent magnet excitation polarization suppression system based on PID control according to claim 1 is characterized in that: When it is monitored that the final flow value is 0 within the first preset time period, the perturbation coil drive is switched to the energy-saving mode.

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