Shaft frequency electric field suppression method and system based on current compensation

Abstract

The invention belongs to the technical field of reducing signals of a ship shaft frequency electric field, and discloses a shaft frequency electric field suppression method based on current compensation, which comprises the following steps of: measuring a shaft frequency electric field signal through an electric field sensor arranged near a field source (mainly a propeller) at the tail of a ship body, and establishing an AR (Augmented Reality) model on the basis; predicting the value of the shaft frequency electric field at the next moment through the model; meanwhile, a pair of compensation anodes is arranged near the field source, and a reverse value of a predicted value is output, so that the purpose of suppressing the signal intensity of the shaft frequency electric field is achieved. According to the invention, the prejudice that the shaft frequency electric field needs to be suppressed through an active or passive shaft grounding system is overcome. The control process is combined with a ship body anti-corrosion system, and the system of the ship is simplified.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal for reducing the shaft-frequency electric field of ships, and particularly relates to a method and system for suppressing the shaft-frequency electric field based on current compensation. Background Art

[0002] At present, certain research has been conducted on the characteristic control of the shaft-frequency electric field of ships, and the main achievement is the active shaft grounding system. However, a problem has been found during the testing of this system: the active shaft grounding system requires additional space inside the hull and the relationship between the carbon brush and the slip ring needs to be considered. The main purpose of the present invention is to propose a method for suppressing the shaft-frequency electric field based on current compensation inspired by the idea of electrostatic field compensation.

[0003] Currently, some countries adopt a passive grounding system, which connects the hull to the rotating shaft through a carbon brush and a slip ring. Since the low impedance of the grounding brush avoids the fluctuation of the bearing impedance, the extremely low-frequency electric field of the ship is weakened; or an active grounding system is adopted, and the electrical connection between the propeller and the stern shaft and between the stern shaft and the hull is cut off to weaken the extremely low-frequency electric field of the ship.

[0004] Taking the electrochemical corrosion system composed of the propeller and the hull as an example, the basic principle of the current compensation technology is as follows. A compensation anode is arranged near the propeller, and the current output by it is opposite to the direction of the current generated by natural corrosion. When the compensation current makes the hull potential tend to be near the self-equilibrium potential, the corrosion current value on the hull surface approaches 0, and the electric dipole moment approaches 0. At this time, the compensated electric dipole moment is significantly smaller than the electric dipole moment of natural corrosion, achieving the purpose of reducing the electric dipole moment.

[0005] Through the above analysis, the problems and defects existing in the prior art are as follows:

[0006] The active shaft grounding system requires additional space inside the hull and the relationship between the carbon brush and the slip ring needs to be considered. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a method for suppressing the shaft-frequency electric field based on current compensation.

[0008] The present invention is implemented as follows. A method for suppressing the shaft-frequency electric field based on current compensation includes:

[0009] Step 1, measuring the shaft-frequency electric field signal of the ship and establishing an AR model to predict the signal of the ship's shaft-frequency electric field;

[0010] Step 2, after obtaining the signal intensity of the electric field, the control module calculates the magnitude of the output current corresponding to the predicted reverse value, and outputs a reverse current into the seawater through a compensation anode arranged near the field source to control the intensity of the ship's shaft-frequency electric field;

[0011] The execution steps of each step are as follows:

[0012] The shaft-frequency electric field signal of the ship is measured by an electric field sensor arranged near the field source at the ship's hull tail;

[0013] The output of the reverse current is through a compensation anode arranged near the field source at the ship's hull tail;

[0014] The output of the reverse current is used to reduce the signal intensity of the shaft-frequency electric field;

[0015] The field source at the ship's hull tail is mainly a propeller.

[0016] Further, the electric field signal used to control the current output is predicted by an AR model;

[0017] The current used to control the ship's shaft-frequency electric field signal is directly introduced into the seawater;

[0018] The suppression of the shaft-frequency electric field is to control the output current using the predicted shaft-frequency electric field signal;

[0019] The electric field intensity of a horizontal DC current element in seawater: In the rectangular coordinate system o-xyz, assume that the horizontal current element is at (0, 0, z'), the current is I, and the length is Δl, then the electric field expression generated by it in seawater can be deduced as:

[0020]

[0021] Formulas (1) to (3) are the electric field intensities of the DC current element in the x, y, and z directions in seawater respectively; in Formulas (1) to (3): R1 and R2 are the distances from (x, y, z) and (x, y, -z) to the current element respectively, The electric field intensity generated by the current element is: σ1 and σ0 are the conductivities of seawater and air respectively.

[0022] Further, the prediction of the AR model for the shaft-frequency electric field signal is performed using the shaft-frequency electric field signal before the prediction point.

[0023] Further, a pair of compensation anodes are arranged near the field source to output a reverse current into the seawater.

[0024] Further, the AR model measures the shaft-frequency electric field signal through an electric field sensor arranged near the field source (mainly a propeller) at the ship's hull tail.

[0025] Furthermore, the coefficients of the AR model obtained by predicting the signal of the shaft-frequency electric field by the AR model need to be updated as the ship state changes;

[0026] The signal of the shaft-frequency electric field before the prediction point is measured by an electric field sensor arranged near the field source (mainly the propeller) at the hull tail.

[0027] Another object of the present invention is to provide a shaft-frequency electric field suppression system based on current compensation, including:

[0028] A measurement module, configured to measure the shaft-frequency electric field signal of the ship and establish an AR model to predict the signal of the ship shaft-frequency electric field;

[0029] A control module, configured to calculate the magnitude of the output current corresponding to the predicted reverse value after obtaining the signal intensity of the electric field, and output a reverse current to the seawater through a compensation anode arranged near the field source, for controlling the intensity of the ship shaft-frequency electric field.

[0030] Another object of the present invention is to provide a computer device, the computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the shaft-frequency electric field suppression method based on current compensation.

[0031] Another object of the present invention is to provide a computer-readable storage medium, storing a computer program, and when the computer program is executed by a processor, the processor executes the steps of the shaft-frequency electric field suppression method based on current compensation.

[0032] Another object of the present invention is to provide an information data processing terminal, and the information data processing terminal is used to implement the shaft-frequency electric field suppression system based on current compensation.

[0033] Combined with the above technical solutions and the solved technical problems, the advantages and positive effects of the technical solutions to be protected by the present invention are:

[0034] First, at the present stage, the control of the shaft-frequency electric field at home and abroad mainly relies on the active shaft grounding system and the passive shaft grounding system. Both of these two systems need to additionally occupy valuable hull space. However, the present invention can effectively control the shaft-frequency electric field without additional devices, filling the technical gap in the domestic and foreign industries.

[0035] The present invention provides a method for suppressing the shaft-frequency electric field based on current compensation. By means of an electric field sensor arranged near the field source (mainly the propeller) at the stern of the hull, the shaft-frequency electric field signal is measured. On this basis, an AR model is established, and the value of the shaft-frequency electric field at the next moment is predicted through the model. At the same time, a pair of compensating anodes is arranged near the field source to output the reverse value of the predicted value, so as to achieve the purpose of suppressing the intensity of the shaft-frequency electric field signal.

[0036] Second, after the successful transformation of the technical solution of the present invention, significant advantages and potential will be demonstrated. Through the unique reverse compensation current mechanism, the intensity of the shaft-frequency electric field signal can be efficiently suppressed. Different from the traditional scheme, this technology can achieve precise control of the shaft-frequency electric field without additional complex devices. This characteristic brings two direct benefits: First, it effectively saves the extremely precious hull space, making the internal space layout of the ship more reasonable and efficient; Second, it greatly reduces the construction cost of the ship, achieving cost reduction in aspects such as material procurement, equipment installation and subsequent maintenance, bringing considerable economic benefits to shipbuilding enterprises. More importantly, the present invention opens up a new path in the field of shaft-frequency electric field control. With innovative technical means, it meets the urgent needs of the ship industry for high-efficiency and low-cost shaft-frequency electric field control solutions, and has broad commercial application prospects.

[0037] In the field of shaft-frequency electric field control, there has long been a common technical prejudice, that is, it is considered that the shaft-frequency electric field can only be suppressed through an active or passive shaft grounding system. However, the present invention has successfully broken this inherent perception.

[0038] The present invention takes a different approach and cleverly combines the control process with the hull anti-corrosion system. This innovative combination method not only breaks through the limitations of traditional technical ideas, but also greatly simplifies the overall system of the ship. The originally complex and independent shaft-frequency electric field control and hull anti-corrosion systems are integrated and optimized within the technical framework of the present invention. The redundant parts between the systems are reduced, the probability of system failures is lowered, and the overall operation stability and reliability of the ship are improved. From the perspective of industry development, the achievement of the present invention in overcoming technical prejudices provides new ideas and directions for the further development of ship engineering technology, and is expected to promote the technological innovation and upgrading of the entire industry. Description of the Drawings

[0039] Figure 1 is a flowchart of the method for suppressing the shaft-frequency electric field based on current compensation provided by an embodiment of the present invention.

[0040] Figure 2 is a block diagram of the structure of the system for suppressing the shaft-frequency electric field based on current compensation provided by an embodiment of the present invention.

[0041] Figure 3It is a schematic diagram of the control process of the shaft-frequency electric field provided by an embodiment of the present invention.

[0042] Figure 4 It is a schematic diagram of the structure of the active shaft grounding system provided by an embodiment of the present invention.

[0043] Figure 5 It is a prediction diagram of the ship shaft-frequency electric field signal provided by an embodiment of the present invention.

[0044] Figure 6 It is a schematic diagram of the structure of the control system of the shaft-frequency electric field provided by an embodiment of the present invention.

[0045] Figure 7 It is a diagram of the 4Hz original signal and the signal after band-pass digital filtering provided by an embodiment of the present invention.

[0046] Figure 8 It is a diagram of the 4Hz signal after signal control and the value after band-pass digital filtering provided by an embodiment of the present invention.

[0047] Figure 9 It is an effect diagram of the 4Hz signal control provided by an embodiment of the present invention.

[0048] Figure 10 It is a diagram of the 7Hz original signal and the signal after band-pass digital filtering provided by an embodiment of the present invention.

[0049] Figure 11 It is a diagram of the 7Hz signal after signal control and the value after band-pass digital filtering provided by an embodiment of the present invention.

[0050] Figure 12 It is an effect diagram of the 7Hz signal control provided by an embodiment of the present invention. Specific embodiments

[0051] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] As Figure 1 shown, a method for suppressing shaft-frequency electric field based on current compensation provided by an embodiment of the present invention includes the following steps:

[0053] S101, measure the shaft-frequency electric field signal of the ship, and establish an AR model to predict the signal of the ship shaft-frequency electric field;

[0054] S102, after obtaining the signal intensity of the electric field, calculate the magnitude of the output current corresponding to the predicted reverse value through the control module, and output a reverse current to the seawater through the compensation anode set near the field source to control the intensity of the ship shaft-frequency electric field.

[0055] During the navigation of a ship, the rotation of the propeller causes changes in the electric field distribution of the surrounding seawater, thereby generating a specific shaft-frequency electric field signal. This electric field signal not only affects the electromagnetic stealth performance of the ship itself but may also become a signal source that can be detected and tracked. Therefore, accurately measuring and suppressing this electric field signal is an important means to enhance the stealth ability of the ship. For this purpose, the present invention first measures the shaft-frequency electric field through an electric field sensor installed near the field source (i.e., the propeller) at the tail of the ship's hull, collects the time-varying signal of the electric field, and uses an Auto-Regressive (AR) model to predict it. The AR model can learn the variation law of the electric field signal based on historical data, thereby achieving accurate prediction of future electric field signals and providing a reference basis for subsequent compensation control.

[0056] After obtaining the predicted signal of the shaft-frequency electric field, the system calculates the corresponding reverse current to offset the influence of the original electric field. Specifically, the control module calculates the magnitude of the compensation current required according to the signal strength predicted by the AR model and outputs a reverse current into the seawater through a compensation anode installed near the field source at the tail of the ship's hull. The compensation anode forms an electric field in the seawater through current injection, which is opposite in direction and equal in intensity to the original shaft-frequency electric field, so that the two cancel each other out, thereby effectively reducing the shaft-frequency electric field signal of the ship and reducing the possibility of being detected. This method based on current compensation can achieve precise suppression of the shaft-frequency electric field without affecting the normal navigation of the ship.

[0057] Due to the changes in factors such as seawater conductivity, temperature, and ship speed, the shaft-frequency electric field signal may fluctuate under different working conditions. Therefore, the present invention adopts a closed-loop control strategy to dynamically adjust the compensation current. Specifically, while the compensation anode outputs current, the system continuously monitors the change of the shaft-frequency electric field at the tail of the ship and compares the actually measured electric field data with the data predicted by the AR model. If it is detected that there is still a residual effect in the compensated electric field signal, the control module will automatically adjust the amplitude and phase of the compensation current to further optimize the suppression effect. This adaptive compensation mechanism can ensure that the system always maintains a high-efficiency suppression ability for the shaft-frequency electric field in a complex marine environment.

[0058] The method for suppressing the shaft-frequency electric field based on current compensation proposed by the present invention has the advantages of strong real-time performance, high adaptability, and good stealth effect. Compared with traditional electromagnetic shielding or structural optimization methods, this method reduces the intensity of the shaft-frequency electric field signal from the source through active compensation, making the ship more stealthy in front of underwater detection systems. In addition, the implementation cost of this method is relatively low, and it is easy to integrate into the existing ship electromagnetic stealth system. It can be widely applied to the stealth design of military submarines and ships, and can also be used in the fields of marine exploration and environmental monitoring to reduce the impact of artificial electric fields on the marine ecological environment.

[0059] In step S101, a sensor is used to measure the shaft-frequency electric field signal around the ship in real time, and the electric field intensity and frequency characteristics are obtained. The measurement data is transmitted to the measurement module, and the measurement module models the shaft-frequency electric field signal based on the autoregressive (AR) model. The AR model analyzes historical signal data to predict the future change trends of the electric field signal, including intensity and phase, providing accurate input data for the calculation of the reverse compensation current.

[0060] In step S102, the control module receives the electric field signal predicted by the AR model and calculates the compensation current value that generates the corresponding reverse electric field. The control module determines the magnitude and direction of the reverse current through a specific algorithm to match the intensity and phase of the shaft-frequency electric field signal. This process dynamically considers environmental parameters such as seawater conductivity and the ship's motion state to ensure that the reverse current can effectively cancel the target electric field signal.

[0061] The compensation anode is set near the shaft-frequency electric field source of the ship to output the reverse current calculated by the control module into the seawater. The output path and intensity of the compensation current are precisely regulated to weaken or even completely cancel the shaft-frequency electric field signal in the target area. The output at this stage is closely combined with the prediction model and real-time feedback data to ensure the efficiency of the electric field suppression process.

[0062] The system introduces a closed-loop control mechanism to monitor the suppression effect of the compensation current on the shaft-frequency electric field in real time. The measurement module transmits the feedback signal to the control module, and the control module dynamically adjusts the magnitude and direction of the reverse current according to the feedback result to optimize the electric field suppression effect. Through this real-time dynamic adjustment mechanism, the system maintains a stable and efficient operating state in a complex marine environment.

[0063] The execution steps of each step are as follows:

[0064] The shaft-frequency electric field signal of the ship is measured by an electric field sensor set near the field source at the stern of the hull;

[0065] The output of the reverse current is through a compensation anode set near the field source at the stern of the hull;

[0066] The output of the reverse current is used to reduce the signal intensity of the shaft-frequency electric field;

[0067] The field source at the stern of the hull is mainly the propeller.

[0068] The electric field signal for controlling the current output provided by the embodiment of the present invention is predicted by the AR model;

[0069] The current for controlling the shaft-frequency electric field signal of the ship is directly introduced into the seawater;

[0070] The suppression of the shaft-frequency electric field utilizes the predicted shaft-frequency electric field signal to control the output current;

[0071] The electric field intensity of a horizontal direct current element in seawater: In the rectangular coordinate system o-xyz, assume that the horizontal current element is at (0, 0, z'), the current is I, and the length is Δl. Then, the electric field expression generated by it in seawater can be deduced as follows:

[0072]

[0073] Formulas (1) to (3) are the electric field intensities of the direct current element in the x, y, and z directions in seawater respectively; in Formulas (1) to (3): σ1 and σ0 are the conductivities of seawater and air respectively.

[0074] The AR model provided by the embodiment of the present invention predicts the signal of the shaft-frequency electric field by using the signal of the shaft-frequency electric field before the prediction point.

[0075] The embodiment of the present invention provides a method of outputting a reverse current into seawater by setting a pair of compensating anodes near the field source.

[0076] The AR model provided by the embodiment of the present invention measures the shaft-frequency electric field signal through an electric field sensor arranged near the field source (mainly the propeller) at the tail of the ship's hull.

[0077] The coefficients of the AR model obtained by the prediction of the signal of the shaft-frequency electric field provided by the embodiment of the present invention need to be updated as the ship's state changes;

[0078] The signal of the shaft-frequency electric field before the prediction point is measured by an electric field sensor arranged near the field source (mainly the propeller) at the tail of the ship's hull.

[0079] As Figure 2 shown, a shaft-frequency electric field suppression system based on current compensation provided by the embodiment of the present invention includes:

[0080] A measurement module, which is used to measure the shaft-frequency electric field signal of the ship and establish an AR model to predict the signal of the ship's shaft-frequency electric field;

[0081] A control module, which is used to calculate the magnitude of the output current corresponding to the predicted reverse value through the control module after obtaining the signal intensity of the electric field, and output a reverse current into seawater through the compensating anode arranged near the field source to control the intensity of the ship's shaft-frequency electric field.

[0082] The measurement module is used to monitor the shaft-frequency electric field signal around the ship in real time. After collecting the electric field intensity and frequency information through sensors, the measurement module establishes an autoregressive (AR) model based on the collected data to predict the change trend of the shaft-frequency electric field signal. The AR model uses historical signal data for calculation, and can accurately predict the intensity and phase characteristics of the electric field signal, providing a basis for the generation of subsequent compensation current.

[0083] The control module receives the shaft-frequency electric field signal provided by the measurement module, and calculates the corresponding reverse electric field compensation current value based on the signal predicted by the AR model. The control module uses an algorithm to determine the optimal magnitude and direction of the reverse current to effectively cancel the shaft-frequency electric field signal in the target area. The dynamic change characteristics of the electric field signal and environmental parameters such as the conductivity and temperature of seawater are considered in this calculation process.

[0084] The compensation anode is arranged near the main area of the ship's shaft-frequency electric field and is used to output reverse compensation current into the seawater. The control module controls the magnitude and direction of the current output by the compensation anode, so that the electric field intensity of the compensation current matches the signal intensity of the original shaft-frequency electric field, thereby achieving the weakening or even complete cancellation of the electric field. By adjusting the output current in real time, this system can dynamically adapt to complex marine environments.

[0085] The system adopts a closed-loop control mechanism. The measurement module monitors the suppression effect of the compensation current on the shaft-frequency electric field in real time and transmits the feedback signal to the control module. The control module further optimizes the magnitude and direction of the compensation current according to the feedback result to ensure that the system always maintains the optimal suppression state. This closed-loop design effectively improves the stability and anti-interference ability of the system.

[0086] The present invention also provides a computer device with a built-in memory and a processor. When the computer program stored in the memory is executed by the processor, it is responsible for implementing the above-mentioned measurement, modeling, calculation, and control functions. The program is based on efficient signal processing and control algorithms to ensure the fast response and high-precision control of the system.

[0087] The information data processing terminal is used to monitor and adjust the operating state of the system, supporting real-time data visualization and parameter setting adjustment. In addition, the computer-readable storage medium stores the core program of the control system, facilitating the upgrade and maintenance of the system. This design improves the scalability and practicability of the system and is applicable to various ship environments and marine application scenarios.

[0088] Specific implementation of the present invention:

[0089] The signal suppression process of the present invention for the shaft-frequency electric field is as Figure 3 shown.

[0090] The active shaft grounding system, and its schematic diagram is shown in Figure 4.

[0091] The execution methods of each step are as follows:

[0092] Measure the shaft-frequency electric field signal through an electric field sensor set near the field source (mainly the propeller) at the stern of the hull.

[0093] Establish an AR model to predict the signal of the ship's shaft-frequency electric field.

[0094] The AR model is a mathematical model with all poles. Its basic idea is to assume that the process x(n) under study is the output of a linear system H(z) excited by a white noise sequence u(n) as the input, where is a linear shift-invariant discrete causal system. A p-order AR model is equivalent to a p-order linear predictor. According to the known sequence x(n), its autocorrelation function r x (m) or its estimated value the p + 1 parameters a(1), a(2), …, a(p) of the model and the variance σ 2 can be obtained.

[0095] Collect the shaft-frequency electric field signal of the ship by measuring the anode, send the collected electric field signal to the analysis device, obtain the parameters a(1), a(2), …, a(p) of the AR model through the calculation of the AR model, and predict the signal of the ship's shaft-frequency electric field through this data to obtain the data of the ship's shaft-frequency electric field, such as Figure 5 is the signal prediction diagram of the ship's shaft-frequency electric field.

[0096] However, for ships in different states, it is necessary to recalculate the parameters of the AR model to ensure the accuracy of the prediction of the ship's shaft-frequency electric field signal.

[0097] After obtaining the shaft-frequency electric field data of the ship, the control of the ship's shaft-frequency electric field signal can be carried out.

[0098] The electric field intensity of a horizontal DC current element in seawater: In the rectangular coordinate system o-xyz, assume that the horizontal current element is at (0, 0, z'), the current is I, and the length is Δl. Then the electric field expression generated by it in seawater can be deduced as:

[0099]

[0100] Formulas (1) to (3) are the electric field intensities of the DC current element in the x, y, and z directions in seawater respectively. In formulas (1) to (3): σ1 and σ0 are the conductivities of seawater and air respectively.

[0101] Based on the electric field strength expressions of DC current elements and time - harmonic current elements in seawater, the electric field of a ship can be modeled. Within a certain area, seawater and the seabed can be regarded as homogeneous and linear conductive media. The superposition of the electric fields generated by DC current elements simulates the static electric field of the ship, and the superposition of the electric fields generated by time - harmonic current elements simulates the shaft - frequency electric field of the ship. If the distribution of the current elements is reasonable, a high fitting accuracy can be achieved in simulating the ship's electric field in a certain frequency band. Therefore, the cancellation of the ship's shaft - frequency electric field can be carried out by setting appropriate time - harmonic current elements and applying an electric field with the same magnitude and opposite direction as the field source to control its magnitude.

[0102] E i is the measured value for each sampling, D i is the value of the reverse electric field output after each sampling and calculation, Y i is the margin for each time (i.e., the measured value of the ship's electric field for the next sampling).

[0103] After the system starts working, through the electric field sensor set near the field source at the ship's tail (mainly the propeller), the electric field value E0 of the ship at time t0 is measured. The control module uses the voltage D0 = - KE0 to control the current output module to apply a reverse current to the seawater through the compensation anode set at the ship's tail for the control of the shaft - frequency electric field; the ship's measurement anode measures the electric field value E i of the ship at time t i , and the shaft - frequency electric field control module uses the voltage D i = - K(E0 + E1+…+E i )(where i = 0, 1, 2…n) to control the current output module to apply a reverse current to the seawater. The physical meaning of the coefficient K is to convert the electric field value measured by the ship's electric field measurement module to the electric field generated by the current element of the electricity - generating unit. It can be obtained by the following method:

[0104] (1) Introduce a steady current into the seawater. This steady current should be as large as possible within the measurement range of the ship's electric field measurement module to generate a steady electric field in the seawater;

[0105] (2) The measurement anode set at the ship's tail measures the electric field value E1 in the seawater;

[0106] (3) If E1≠0, the control module uses D = E1 to control the current output module to apply a reverse current to the seawater for the signal control of the shaft - frequency electric field;

[0107] (4) Measure the electric field value E2 in the seawater again;

[0108] (5) If E2≠0, the control module uses D = -(E1 + E2) to control the current output module to apply a reverse current to the seawater for the signal control of the shaft - frequency electric field;

[0109] (6) Until En = 0, the proportionality coefficient K can be obtained as: K = (E1 + E2 + … E n ) / E1.

[0110] The present invention is mainly applied to the field of suppressing shaft-frequency electric fields.

[0111] Figure 6 It is a schematic structural diagram of a control system for shaft-frequency electric fields.

[0112] Beneficial effects: Through experiments, it can be known that the system has an obvious effect on controlling shaft-frequency electric field signals. From Figure 7 and Figure 8 、 Figure 9 It can be found that for a 4Hz signal, in the amplitude spectrum of the signal, the original signal at 4Hz is reduced from 3.399dB to -5.161dB of the controlled signal, that is, the amplitude of the controlled signal is reduced to 13.93% of the original signal. From Figure 10 and Figure 11 、 Figure 12 It can be found that for a 7Hz signal, in the amplitude spectrum of the signal, the original signal at 7Hz is reduced from 2.708dB to -5dB of the controlled signal, that is, the amplitude of the controlled signal is reduced to 16.95% of the original signal.

[0113] Table 1

[0114] Signal frequency / Hz Original signal amplitude / dB Amplitude of the signal after control / dB Suppression ratio / % 4 3.399 -5.161 13.93 7 2.708 -5 16.95

[0115] It can be found from the experiment that the filter has a slight attenuation effect on the 4Hz and 7Hz signals in the passband, but the overall impact is not significant. Although the control effect of the entire system on different frequency signals decreases slightly as the signal frequency increases, analyzing the reason, it is mainly because the AD sampling and DA output rates are fixed, and as the frequency increases, the number of sampling points per unit period will decrease, resulting in a slight reduction in the control effect. Moreover, since the control core consists of a data acquisition card controlled by a computer, the control program is developed based on the labview environment under the windows system. And the windows system itself has a time error of the order of milliseconds. So although the AD sampling rate is set to 1000Hz, the processing ability of the program is limited. After measurement, it is found that the DA end can only change the output value every 10 points, that is, the output rate can only reach 100Hz. For a 4Hz signal, the system only performs 25 samplings and outputs; for a 7Hz signal, the system only performs 14 samplings and outputs. Therefore, as the signal frequency increases, the control effect of the system will deteriorate.

[0116] Therefore, it is necessary to replace the control core of the system with a more efficient device to further improve the performance of the system.

[0117] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those of ordinary skill in the art can understand that the above devices and methods can be implemented using computer-executable instructions and / or included in processor control code, such as provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above hardware circuits and software such as firmware.

[0118] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. An axial frequency electric field suppression method based on current compensation, characterized in that It includes the following steps: Measure the shaft-frequency electric field signal through an electric field sensor arranged near the field source at the stern of the hull; Based on the measured shaft-frequency electric field signal, establish an autoregressive (AR) model to predict the shaft-frequency electric field signal; Calculate the compensation current according to the predicted shaft-frequency electric field signal; Output the compensation current to seawater through a compensation anode arranged near the field source at the stern of the hull; Adjust the amplitude and phase of the compensation current to form a reverse compensation with the shaft-frequency electric field signal and reduce the signal intensity of the shaft-frequency electric field.

2. The method for suppressing the shaft-frequency electric field based on current compensation according to claim 1, wherein, The electric field signal for controlling the current output is predicted by the AR model; The current for controlling the shaft-frequency electric field signal of the ship is directly introduced into seawater; The suppression of the shaft-frequency electric field uses the predicted shaft-frequency electric field signal to control the output current; The electric field intensity of a horizontal DC current element in seawater: In a rectangular coordinate system o-xyz, assume that the horizontal current element is at (0, 0, z'), the current is I, and the length is Δl, then the electric field expression generated by it in seawater can be deduced as: Equations (1) to (3) are the electric field strengths of a DC current element in the x, y, and z directions in seawater; in Equations (1) to (3): σ1 and σ0 are the conductivities of seawater and air, respectively.

3. The method for suppressing axial frequency electric field based on current compensation according to claim 1, wherein The prediction of the shaft-frequency electric field signal by the AR model is carried out using the shaft-frequency electric field signal before the prediction point.

4. The method for suppressing the shaft-frequency electric field based on current compensation according to claim 1, characterized in that, Output a reverse current to seawater by arranging a pair of compensation anodes near the field source.

5. The method for suppressing the shaft-frequency electric field based on current compensation according to claim 1, wherein The AR model measures the shaft-frequency electric field signal through an electric field sensor arranged near the field source (mainly the propeller) at the stern of the hull.

6. The method for suppressing the shaft-frequency electric field based on current compensation according to claim 1, wherein The coefficients of the AR model obtained by predicting the shaft-frequency electric field signal need to be updated as the ship's state changes; The shaft-frequency electric field signal before the prediction point is measured by an electric field sensor arranged near the field source (mainly the propeller) at the stern of the hull.

7. A current compensation-based shaft-frequency electric field suppression system for implementing the current compensation-based shaft-frequency electric field suppression method according to any one of claims 1-6, characterized in that, The shaft-frequency electric field suppression system based on current compensation includes: A measurement module for measuring the shaft-frequency electric field signal of the ship and establishing an AR model to predict the shaft-frequency electric field signal of the ship; A control module for, after obtaining the signal intensity of the electric field, calculating the magnitude of the output current corresponding to the predicted reverse value through the control module, and outputting a reverse current to seawater through a compensation anode arranged near the field source to control the intensity of the shaft-frequency electric field of the ship.

8. A computer device, characterized in that, The computer device includes a memory and a processor. When the computer program stored in the memory is executed by the processor, the processor executes the steps of the shaft-frequency electric field suppression method based on current compensation according to any one of claims 1-6.

9. A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor executes the steps of the shaft-frequency electric field suppression method based on current compensation according to any one of claims 1-6.

10. An information data processing terminal, characterized in that, The information data processing terminal is used to implement the shaft-frequency electric field suppression system according to claim 7.

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