Method and system for resonance enhancement of a narrow gap of a floating breakwater by a floating wave energy device

Abstract

The application relates to the technical field of wave energy utilization, and discloses a floating wave energy device and a narrow-slot resonance synergistic method and system of a floating breakwater. The method comprises the following steps: performing frequency spectrum analysis on a narrow-slot wave surface sequence to obtain a narrow-slot wave energy spectrum width parameter and a narrow-slot wave surface amplification factor, and generating a surface type switching instruction according to the comparison results of the two parameters with respective preset threshold values; triggering the rotation of a WEC floater around a vertical shaft according to the surface type switching instruction, interchanging a symmetrical section and an asymmetric triangular baffle section, converting transient hydrodynamic excitation generated in the rotation process into electric energy through a power output device, and obtaining a modal conversion benefit increment; combining the modal conversion benefit increment with the difference between the wave energy conversion efficiencies before and after switching, iteratively correcting the preset threshold value, and obtaining an updated surface type switching instruction generation rule. The application realizes the continuous collaborative optimization of the wave energy conversion efficiency and the wave dissipation performance under wide-frequency changing sea conditions.

Description

Technical Field

[0001] This application relates to the field of wave energy utilization technology, and in particular to a float-type wave energy device and a method and system for enhancing the resonance effect of a narrow slot in a floating breakwater. Background Technology

[0002] The integration of float-type wave energy conversion devices (WECs) with floating breakwaters is an important research direction in the field of wave energy utilization. In existing technologies, oscillating float-type WECs are placed on the wave-facing side of floating breakwaters, forming a narrow slit of a specific width between them. When the incident wave frequency matches the natural frequency of the water in the slit, the fluid within the slit resonates, and the wave surface within the slit rises significantly. Under this resonance condition, the wave energy conversion efficiency of a symmetrical WEC float can reach up to 61%, breaking through the theoretical upper limit of 50% for single-degree-of-freedom oscillators. It also has wave-damping and wave-dissipating functions, making it highly valuable for engineering applications.

[0003] However, existing WEC and floating breakwater integration systems have the following technical shortcomings: First, the narrow-slot resonant frequency is statically determined by geometric parameters such as the float spacing and WEC draft, and cannot be adaptively adjusted under wide-frequency sea conditions, resulting in the system only operating efficiently at specific design wave frequencies; Second, existing research reveals that narrow-slot resonance has a positive gain effect on symmetrical WEC floats, but a suppressive effect on asymmetrical WEC floats with better wide-frequency performance, making it impossible to achieve both resonance gain capability and wide-frequency coverage capability in the same device; Third, existing WEC control systems use PTO damping parameters or device mass distribution as control variables, and the control path remains at the electrical level, failing to solve the decisive influence of float cross-sectional shape on the narrow-slot resonance properties from the physical structure level.

[0004] Since the narrow-slit resonance properties are determined by the cross-sectional shape of the WEC float, and the cross-sectional shape of the float is fixed and cannot be switched in the existing technology, the hydrodynamic advantages of symmetrical and asymmetrical cross-sections cannot be called on demand on the same device. Precisely because the float cross-section cannot be switched on demand, the system cannot actively trigger the resonance gain mode under narrow-frequency concentrated sea states, and cannot actively switch to the broadband coverage mode under wide-frequency dispersed sea states. As a result, the mode switching itself lacks an effective decision basis and feedback correction mechanism, and the spectral width decision threshold cannot be adaptively updated with the long-term evolution of sea states. The accuracy of the switching decision of the system continues to decline during long-term operation in different sea areas and seasons. Summary of the Invention

[0005] This application provides a method and system for enhancing the narrow-slot resonance of a float-type wave energy device and a floating breakwater. It solves the problems that the symmetrical cross-section resonance gain capability and the asymmetrical cross-section broadband coverage capability cannot be switched on demand on the same device in the existing WEC and floating breakwater integrated system, as well as the problem that the narrow-slot resonance mode decision threshold cannot be adaptively corrected with the long-term evolution of sea state. It realizes the continuous synergistic optimization of wave energy conversion efficiency and wave dissipation performance under broadband sea state changes.

[0006] In a first aspect, this application provides a method for enhancing the resonance effect of a float-type wave energy device and a narrow slot resonance effect of a floating breakwater, the method comprising: Step S1: Collect the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater to obtain the narrow gap wave series; Step S2: Perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor. Based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds, generate a surface shape switching command. Step S3: According to the surface shape switching command, trigger the WEC float to rotate around the vertical axis, and exchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side. The transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation is converted into electrical energy through the power output device to obtain the modal conversion benefit increment. Step S4: Combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after switching, and iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

[0007] Secondly, this application provides a float-type wave energy device and a floating breakwater narrow-slot resonance enhancement system, the float-type wave energy device and the floating breakwater narrow-slot resonance enhancement system comprising: The acquisition module is used to acquire the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater, and obtain the narrow gap wave series; The generation module is used to perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor, and generate a surface shape switching command based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds. The trigger module is used to trigger the WEC float to rotate around the vertical axis according to the surface shape switching command, interchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side, and convert the transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation into electrical energy through the power output device to obtain the modal conversion benefit increment. The correction module is used to combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after the switching, and to iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

[0008] Thirdly, a float-type wave energy device and a floating breakwater narrow-slot resonance enhancement device are provided, comprising: a memory and at least one processor, wherein the memory stores instructions; the at least one processor invokes the instructions in the memory to cause the float-type wave energy device and the floating breakwater narrow-slot resonance enhancement device to perform the above-described float-type wave energy device and floating breakwater narrow-slot resonance enhancement method.

[0009] Fourthly, a computer-readable storage medium is provided, wherein instructions are stored therein, which, when executed on a computer, cause the computer to perform the above-described method for enhancing the resonance effect of the float-type wave energy device and the narrow slot of the floating breakwater.

[0010] The technical solution provided in this application obtains a slit wavefront sequence by real-time acquisition of wavefront rise time series within a narrow slit water area, and simultaneously extracts two physical quantities—the slit wave energy spectrum width parameter and the slit wavefront amplification factor—through spectral analysis of the slit wavefront sequence. These two parameters are used as a dual-indicator joint decision basis to generate a surface shape switching command. This fundamentally solves the inherent defect of existing technologies that rely on external wave measuring instruments to estimate the incident wave frequency. The slit wave energy spectrum width parameter directly reflects the frequency concentration of fluid wave energy within the slit, and the slit wavefront amplification factor directly reflects the actual intensity of the slit resonance effect. Both indicators originate from the fluid physical signals inside the slit, and the current slit resonance state can be completely described within the device without additional wave measuring equipment. This allows the generation of the surface shape switching command to be based on a direct judgment of the slit resonance properties rather than the incident wave frequency position. This innovative sensing path makes the decision logic highly consistent with the physical essence of slit resonance.

[0011] Triggered by a surface shape switching command, the WEC buoy rotates around its vertical axis, interchanges the symmetrical and asymmetrical triangular baffle sections on the breakwater-facing side. This is the first time that the resonant gain mode of the symmetrical section under narrow-frequency concentrated sea states and the broadband coverage mode of the asymmetrical triangular baffle section under wide-frequency dispersed sea states have been integrated on a single device. This allows the hydrodynamic advantages corresponding to the two cross-sectional shapes in existing technologies to be utilized on demand within a single device. More importantly, during the rotation, the transient hydrodynamic excitation generated by the narrow-slit water body on the buoy is converted into electrical energy by the power output device, resulting in an incremental mode conversion benefit, thus reducing the switching action itself... The event transforms from a purely energy-consuming event into an additional energy-capturing opportunity. Furthermore, the incremental modal conversion benefit is combined with the difference in wave energy conversion efficiency before and after the switch to iteratively correct the preset threshold. This allows the pattern switching command generation rule to continuously self-correct based on the measured effect of each switch. The threshold correction is based on the difference in cross-window statistical efficiency before and after the switch rather than the instantaneous signal at the current moment. This meta-level adaptive mechanism ensures that the decision rule itself continuously approaches the optimal in long-term operation, thereby maintaining the dual-objective synergistic performance of wave energy conversion and wave prevention and dissipation under changing sea conditions in different sea areas and seasons. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of an embodiment of the float-type wave energy device and the floating breakwater narrow slot resonance enhancement method in this application; Figure 2 This is a schematic diagram of the distribution of modality conversion benefit increments in the embodiments of this application. Detailed Implementation

[0014] This application provides a float-type wave energy device and a method and system for enhancing the resonance of a narrow slot in a floating breakwater. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0015] For ease of understanding, the specific process of the embodiments of this application is described below. Please refer to [link / reference]. Figure 1 One embodiment of the float-type wave energy device and the floating breakwater narrow slot resonance enhancement method in this application includes: Step S1: Collect the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater to obtain the narrow gap wave series; Specifically, the narrow-slit wavefront sequence refers to a representative time-domain signal obtained by spatially averaging the instantaneous water level rise time series collected by several capacitive wavefront sensors arranged at equal intervals along the direction of incident wave propagation within the narrow waterway between the WEC buoy and the floating breakwater, and then rolling through a fixed statistical window. The statistical window length is set to 120 seconds because the main energy of ocean waves is concentrated in the 0.05Hz to 1Hz frequency band, and the 120-second window corresponds to a minimum resolution frequency of approximately 0.008Hz, which is sufficient to cover all spectral components within the above frequency band. The sliding step size is set to 10 seconds to ensure the temporal continuity between adjacent windows and to avoid missed detections when sea state changes abruptly.

[0016] Step S2: Perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor. Based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds, generate a surface shape switching command. Specifically, the slit wave energy spectrum width parameter is calculated by jointly taking the zeroth, second, and fourth spectral moments of the slit wave energy density spectrum obtained by the Hanning window weighted fast Fourier transform of the slit wavefront sequence. Its physical meaning is the degree of dispersion of wave energy in the slit along the frequency axis, and its value ranges from zero to one. The closer it is to zero, the more concentrated the wave energy in the slit is at a single frequency, and the more sufficient the slit resonance gain condition is for the symmetrical cross section. The closer it is to one, the more dispersed the wave energy is in a wide frequency band, and the more sufficient the broadband response condition is for the asymmetrical triangular baffle cross section. The slit wavefront amplification factor is obtained by taking the square root of the ratio of the zeroth spectral moment of the slit wavefront sequence to the incident reference wavefront sequence on the wave-facing side. Its physical meaning is the amplification factor of the fluid energy in the slit relative to the incident wave energy. A value greater than one indicates the existence of the slit resonance effect. The initial threshold for spectral width is set to 0.35, and the initial threshold for amplification factor is set to 1.20. Both are continuously updated by an iterative correction mechanism. The initial values ​​are determined based on experimental data of the narrow-slit resonance gain range of the symmetric WEC float.

[0017] Step S3: According to the surface shape switching command, trigger the WEC float to rotate around the vertical axis, and exchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side. The transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation is converted into electrical energy through the power output device to obtain the modal conversion benefit increment. Specifically, the face shape switching command triggers the WEC float to rotate 180° around its vertical axis, swapping the symmetrical section and the asymmetrical triangular baffle section on the breakwater-facing side. The symmetrical section refers to a rectangular section with a horizontal flat bottom on the float, where the ratio of its waterline width to its draft is between 0.6 and 1.0. This ratio range ensures that the heave response of the symmetrical oscillator under narrow-slit resonance conditions meets the hydrodynamic conditions that exceed the 50% theoretical efficiency limit of a single-degree-of-freedom oscillator. The asymmetrical triangular baffle section refers to a section with a triangular baffle fixed to the lower edge of the main float box on the wave-facing side, with a apex angle between 30° and 45° and the lower edge of the baffle extending to 0.6 times the draft. This geometric parameter ensures effective capture of waves in the 0.05Hz to 0.60Hz frequency band on the B side. The incremental benefit of mode switching is obtained by subtracting the transient power generation within the rotation cycle obtained by electromechanical conversion of the vertical transient excitation force sequence and the float heave velocity sequence collected by the triaxial force sensor during rotation from the power output device, and the estimated power generation within the corresponding time of the working mode before switching. When this increment is positive, it indicates that the switching process itself outputs net electrical energy.

[0018] Step S4: Combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after switching, and iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

[0019] Specifically, the difference in wave energy conversion efficiency before and after the switch is obtained by subtracting the average wave energy conversion efficiency within the first complete statistical window after the switch from the average wave energy conversion efficiency within the most recent complete statistical window before the switch. The wave energy conversion efficiency is calculated by dividing the average output power of the power output device by the product of the incident wave power density and the buoy's wave-facing width. The incident wave power density is obtained by using the standard spectral moment formula from the effective wave height and energy period of the reference wavefront sequence. After jointly determining the modal conversion benefit increment and the difference in wave energy conversion efficiency before and after the switch, the slit wave energy spectrum width parameter and the slit wavefront amplification factor that triggered this switch are respectively assigned to the positive or negative switch sample set. The preset threshold for the spectrum width and the preset threshold for the amplification factor are iteratively corrected in the corresponding directions with fixed step sizes of 0.02 and 0.05, respectively. The allowable adjustment range is limited to 0.20 to 0.50 and 1.10 to 1.50, respectively. When the value exceeds the boundary, it is locked at the boundary value. This range is determined based on the physical boundary of the effective range of the slit resonance.

[0020] In one specific embodiment, step S1 includes: In the narrow gap water area between the WEC buoy and the floating breakwater, several capacitive wavefront sensors are arranged at equal intervals along the direction of incident wave propagation. The instantaneous water level rise time series collected by each sensor is spatially averaged to obtain the representative wavefront sequence of the narrow gap. Based on the slit representative wavefront sequence, a rolling truncation process is performed with a fixed statistical window length and a fixed sliding step size to obtain the slit wavefront sequence.

[0021] Specifically, within the narrow slit between the WEC buoy and the floating breakwater, at least five capacitive wavefront sensors are arranged at equal intervals along the direction of incident wave propagation. The minimum number of sensors is five because the wavefront distribution along the wave propagation direction within the narrow slit is spatially non-uniform. With fewer than five measuring points, the spatial average result is highly sensitive to local wavefront anomalies. Using five or more measuring points can control the spatial sampling error within an acceptable range for engineering purposes. Each sensor synchronously collects the instantaneous water level rise time series at a sampling frequency of 20Hz. The sampling frequency of 20Hz is chosen because the main energy of ocean waves is concentrated in the 0.05Hz to 1Hz frequency band, and 20Hz satisfies the Nyquist sampling theorem requirement while allowing sufficient margin. The time series data from N sensors are arithmetically averaged at each time step using equal weighting coefficients. The equal weighting coefficients mean that each sensor has an equal weight in the spatial averaging calculation. The weight value of each sensor is 1 / N, and N is the total number of sensors participating in the averaging. That is, the arithmetic mean of the instantaneous water level rise values ​​collected by N sensors at the same time is directly calculated, eliminating the random errors introduced by local eddies or sensor installation deviations in single-point measurements, and obtaining a representative wave surface sequence of the narrow slit that can represent the overall wave surface motion state within the narrow slit.

[0022] Based on the representative wavefront sequence, a slit wavefront sequence is obtained by rolling and truncating the representative wavefront sequence with a fixed statistical window length of 120 seconds and a fixed sliding step size of 10 seconds. The difference between the representative wavefront sequence and the slit wavefront sequence is that the representative wavefront sequence is a continuous real-time signal, while the slit wavefront sequence is a finite-length analysis unit truncated from the representative wavefront sequence according to fixed rules. Each slit wavefront sequence contains 2400 sampling points, which is the product of 120 seconds and 20 Hz. The statistical window length is set to 120 seconds because the frequency resolution of this window is approximately 0.008 Hz, which can fully resolve the wave energy spectrum components in the range of 0.05 Hz to 1 Hz. The sliding step size is set to 10 seconds to ensure sufficient temporal overlap between adjacent windows, so that the capture delay of sea state changes does not exceed 10 seconds, and the generation opportunity of the surface shape switching command is not missed when the sea state changes rapidly.

[0023] In one specific embodiment, step S2 includes: After applying Hanning window weighting to the narrow slit wavefront sequence, a fast Fourier transform is performed to obtain the narrow slit wave energy density spectrum. Based on the energy density spectrum of the slit wave, the zeroth-order spectral moment, the second-order spectral moment and the fourth-order spectral moment are calculated respectively. The spectral width is then calculated based on the zeroth-order spectral moment, the second-order spectral moment and the fourth-order spectral moment to obtain the energy spectral width parameter of the slit wave. The slit wavefront magnification factor is obtained by taking the square root of the ratio between the zero-order spectral moment of the slit wave energy density spectrum and the zero-order spectral moment of the incident reference wavefront sequence. The slit wave energy spectrum width parameter is compared with the preset threshold of the spectrum width, and the slit wavefront amplification factor is compared with the preset threshold of the amplification factor. Based on the two comparison results, a logical AND operation is performed to obtain the surface shape switching command.

[0024] Specifically, applying Hanning window weighting to the slit wavefront sequence aims to suppress spectral leakage caused by truncation at both ends of the finite-length time series. The Hanning window coefficients are multiplied point-by-point by the 2400 sampling points of the slit wavefront sequence according to the standard formula. A Fast Fourier Transform is then performed on the weighted sequence, with a frequency resolution of approximately 0.008 Hz (20 Hz sampling frequency divided by 2400 window points). The output is the power spectral density of each frequency component within the effective frequency range of 0.05 Hz to 1 Hz, i.e., the slit wave energy density spectrum. This spectrum reflects the distribution of fluid wave energy along the frequency axis within the slit. Based on the slit wave energy density spectrum, the zeroth-order spectral moment is the cumulative integral of the power spectral density values ​​of each frequency component within the range of 0.05 Hz to 1 Hz, reflecting the total wave energy within the slit; the second-order spectral moment is the cumulative integral of the product of the power spectral density values ​​of each frequency component and the square of the corresponding frequency; and the fourth-order spectral moment is the cumulative integral of the product of the power spectral density values ​​of each frequency component and the fourth power of the corresponding frequency. The spectral width parameter of the slit wave is calculated from the zeroth-order spectral moment, the second-order spectral moment, and the fourth-order spectral moment according to the following relationship: the square of the second-order spectral moment is divided by the product of the zeroth-order spectral moment and the fourth-order spectral moment, and then the square root of the positive value of the quotient is subtracted from one to obtain the spectral width parameter of the slit wave. Its value ranges from zero to one. When it approaches zero, it indicates that the wave energy in the slit is highly concentrated at a single frequency, corresponding to the positive gain range of the symmetrical section under the slit resonance condition. When it approaches one, it indicates that the wave energy is dispersed in a wide frequency band, corresponding to the wide frequency response range of the asymmetrical triangular baffle section.

[0025] The slit wavefront amplification factor is obtained by taking the positive square root of the ratio of the zero-order spectral moment of the slit wave energy density spectrum to the zero-order spectral moment calculated using the same method for the incident reference wavefront sequence. Physically, it represents the amplification factor of the total wave energy of the fluid within the slit relative to the total wave energy of the incident wave. A value greater than one indicates the presence of a slit resonance effect and that the fluid energy within the slit is higher than that of the incident wave. The initial preset threshold for spectral width is 0.35, determined based on the upper bound of the measured distribution of the slit wave energy spectrum width parameter of a symmetric WEC float within the slit resonance gain range. The initial preset threshold for the amplification factor is 1.20, determined based on the lower bound of the measured distribution of the slit wavefront amplification factor when the slit resonance effect is significant. The first comparison result is obtained by comparing the slit wave energy spectrum width parameter with the preset threshold of the spectrum width, and the second comparison result is obtained by comparing the slit wavefront amplification factor with the preset threshold of the amplification factor. A logical AND operation is performed on the first comparison result and the second comparison result. That is, when both conditions are met, the slit wave energy spectrum width parameter is less than the preset threshold of the spectrum width and the slit wavefront amplification factor is greater than the preset threshold of the amplification factor, the output command is switched to the surface shape switching to the symmetrical cross-section facing the wave. When either condition is not met, the output command is switched to the surface shape switching to the asymmetrical triangular baffle cross-section facing the wave. Both preset thresholds are continuously updated by the subsequent iterative correction mechanism.

[0026] In one specific embodiment, step S3, triggering the WEC float to rotate around the vertical axis according to the surface shape switching command, includes: The surface shape switching command is compared with the surface shape switching command of the previous control cycle to obtain the modal change trigger signal; Anti-shake timing processing is initiated based on the modal change trigger signal. Within a fixed anti-shake delay time, the consistency of the face switching command is continuously verified to obtain a switching confirmation command. According to the switching confirmation command, the rotational degree of freedom locking mechanism is unlocked in sequence, the stepper motor is driven at a fixed angle, and the rotational degree of freedom locking mechanism is relocked, resulting in the cross-section interchange state.

[0027] Specifically, the face shape switching command output in the current control cycle is compared bit by bit with the face shape switching command output in the previous control cycle. When the two are inconsistent, a valid level signal, i.e., a mode change trigger signal, is output. When the two are consistent, no signal is output. The physical meaning of the mode change trigger signal is the time marker of the first occurrence of the face shape switching requirement. Based on the mode change trigger signal, anti-shake timing is started. The fixed anti-shake delay time is 60 seconds. This is because the spectral width parameter of the narrow slit wave tends to fluctuate around the preset threshold of spectral width during the sea state transition period. The 60-second anti-shake delay can filter out false switching triggered by brief sea state fluctuations lasting less than 60 seconds. Within the anti-shake delay time, the face shape switching command is continuously verified 6 times at 10-second intervals. When all 6 verification results are consistent with the trigger time, a switching confirmation command is output. If any verification result is inconsistent with the trigger time, the timer is reset and the switching is canceled. The physical meaning of the switching confirmation command is a valid cross-section interchange execution permission confirmed after anti-shake verification.

[0028] According to the switching confirmation command, the following three actions are executed in sequence: First, a power-off command is sent to the rotational degree of freedom locking mechanism to switch the electromagnetic locking structure that originally locked the rotational degree of freedom to the unlocked state, so that the WEC float can obtain the motion degree of freedom to rotate around the vertical axis; then, a rotation command is sent to the stepper motor to drive the WEC float to rotate 180 degrees around the vertical axis at an angular velocity of 6 degrees per second. The rotational angular velocity is 6 degrees per second because too fast rotation will cause excessive tangential impact force between the float and the narrow water slit, which will damage the rotational hinge mechanism. 6 degrees per second corresponds to 30 seconds to complete the 180-degree rotation. During this period, the power output device continues to run to capture the transient hydrodynamic excitation generated during the rotation; after the stepper motor is in position, a power-on command is immediately sent to the rotational degree of freedom locking mechanism to relock the rotational degree of freedom, so that the WEC float returns to the pure heave working state. At this time, the symmetrical section and the asymmetrical triangular baffle section are interchanged facing the breakwater side, and the section interchange state is obtained. The section interchange state is the input basis for subsequent judgment of the current working mode and calculation of the mode conversion benefit increment.

[0029] In one specific embodiment, step S3, which involves interchangering the symmetrical cross-section of the WEC buoy with the asymmetrical triangular baffle cross-section on the breakwater-facing side, includes: Based on the cross-section interchange state, when the symmetrical cross section of the WEC float is switched to the side facing the breakwater, a symmetrical oscillating resonance water area is formed between the narrow slot water body and the symmetrical cross section. Based on the cross-section interchange state, when the asymmetric triangular baffle cross section of the WEC float is switched to the side facing the breakwater, the lower edge of the asymmetric triangular baffle cross section extends to a fixed draft ratio below the still water surface, forming an asymmetric guiding water area between it and the narrow slit water body; Based on the current activation state of the symmetrical oscillating resonance water area and the asymmetrical guiding water area, the current working state of the cross section is determined, and the working identifier of the cross section is obtained.

[0030] Specifically, based on the cross-section interchange state, when the symmetrical cross-section is switched to face the breakwater side, the ratio of the waterline width to the draft of the symmetrical cross-section is between 0.6 and 1.0. This ratio range is determined by the hydrodynamic conditions required for the symmetrical oscillator to break through the 50% theoretical efficiency limit of a single-degree-of-freedom oscillator under narrow-slit resonance conditions. When the ratio is below 0.6, the float's heave recovery stiffness is insufficient; when the ratio is above 1.0, the radiation damping is too large, suppressing the resonance response. The bottom of the symmetrical cross-section is a horizontal flat-bottom structure, forming a closed fluid domain with geometrically symmetrical side walls between it and the narrow-slit water body between it and the breakwater. This fluid domain generates symmetrical oscillating motion along the vertical direction under the excitation of the incident wave, i.e., a symmetrical oscillating resonance water area. The vertical motion of the fluid in the symmetrical oscillating resonance water area is superimposed in phase with the heave motion of the WEC float, forming the narrow-slit resonance gain condition. When the asymmetric triangular baffle section is switched to face the breakwater side, the apex angle of the triangular baffle is between 30 and 45 degrees. When the apex angle is less than 30 degrees, the baffle is too sharp, resulting in insufficient structural strength. When the apex angle is greater than 45 degrees, the guiding effect on broadband waves is significantly reduced. The lower edge of the baffle extends to 0.6 times the draft below the still water surface. This ratio is determined by the immersion depth required for the asymmetric section to effectively capture wave energy in the 0.05Hz to 0.60Hz frequency band. It forms a streamlined asymmetric guiding channel with the narrow gap water between the baffle and the breakwater, i.e., an asymmetric guiding water area.

[0031] The cross-sectional operating identifier is determined based on the current activation state of the symmetrical oscillating resonance water area and the asymmetrical guiding water area. The cross-sectional operating identifier is a binary quantity: when the symmetrical oscillating resonance water area is active, the cross-sectional operating identifier takes the first value, indicating that the current WEC buoy is operating with a symmetrical cross-section facing the breakwater side, corresponding to the narrow-slit resonant gain operating mode; when the asymmetrical guiding water area is active, the cross-sectional operating identifier takes the second value, indicating that the current WEC buoy is operating with an asymmetrical triangular baffle cross-section facing the breakwater side, corresponding to the broadband coverage operating mode. The activation states of the two water areas are directly mapped from the cross-sectional interchange state. Only one type of water area is active at any given time. The cross-sectional operating identifier serves as a unique mode identity marker, which is passed into the subsequent transient power generation calculation and mode conversion benefit increment difference processing stages to ensure that data attribution under the two operating modes is not confused.

[0032] In one specific embodiment, in step S3, the transient hydrodynamic excitation generated by the narrow slit water body on the float during rotation is converted into electrical energy via a power output device to obtain the modal conversion benefit increment, including: Based on the cross-sectional working mark, during the rotation of the WEC float, the transient hydrodynamic excitation is collected and processed in real time by a triaxial force sensor to obtain the vertical transient excitation force sequence; The vertical transient excitation force sequence and the float heave velocity sequence are input into the power output device for electromechanical conversion to obtain the transient power generation within the rotation cycle. The difference between the transient power generation during the rotation cycle and the estimated power generation during the corresponding time under the previous working mode is processed to obtain the mode conversion benefit increment.

[0033] Specifically, after confirming that the WEC float has entered the rotation switching process based on the cross-sectional working mark, a triaxial force sensor is installed at the bottom of the float. During rotation, it continuously collects the force components in three directions acting on the float. The vertical component is taken as the effective component of the transient hydrodynamic excitation, resulting in a vertical transient excitation force sequence. The reason for taking the vertical component is that the power output device only responds to the relative motion in the swaying direction of the float; the horizontal component does not perform work through the power output device and is not included in the power generation calculation. The swaying velocity sequence of the float is obtained by integrating the vertical acceleration collected by the accelerometer installed on the float over time. The initial value of the integration is the measured value of the swaying velocity at the beginning of rotation. The vertical transient excitation force sequence and the swaying velocity sequence are multiplied moment by moment and integrated over the entire rotation period. Then, the result is multiplied by the electromechanical conversion efficiency calibration value of 0.85 of the power output device to obtain the transient power generation within the rotation period. The electromechanical conversion efficiency of 0.85 is determined based on the factory calibration data of the power output device. The rotation period is 30 seconds, which is consistent with the time required for the stepper motor to complete a 180-degree rotation.

[0034] The estimated power generation within the corresponding time period under the operating mode before the switchover is calculated by multiplying the average output power of the power output device within the most recent complete statistical window before the switchover by the rotation cycle duration of 30 seconds. This average output power is obtained by calculating the arithmetic mean of the sampled values ​​of the power sensor of the power output device within the statistical window before the switchover. The physical meaning of the estimated power generation is the benchmark value of power generation that could be generated if the current cross-section switchover were not performed and the original operating mode was maintained for 30 seconds. The difference between the transient power generation within the rotation cycle and the estimated power generation is used to obtain the mode conversion benefit increment. When the mode conversion benefit increment is positive, it indicates that the electrical energy generated by the transient hydrodynamic excitation captured by the power output device during the rotation switchover is higher than the power generation generated by maintaining the original mode operation for the same duration, and the switchover process itself is a net output of electrical energy. When the mode conversion benefit increment is negative, it indicates that there is a net energy consumption during the switchover. This result, along with the cross-section operating identifier, is passed into the subsequent preset threshold iterative correction stage as one of the quantitative bases for judging the rationality of this switchover decision.

[0035] Figure 2 This is a schematic diagram of the distribution of modality conversion benefit increments in the embodiments of this application. Figure 2 The statistical distribution of modal conversion benefit increments in 80 area switching samples is shown. The horizontal axis represents the value of the modal conversion benefit increment (unit: Wh), and the vertical axis represents the corresponding number of switching events. The entire sample is divided into two groups, positive benefit increments and negative benefit increments, with the zero-value baseline as the boundary. The positive benefit increment group corresponds to switching events in which the electrical energy generated by the transient hydrodynamic excitation captured by the power output device during the rotation cycle is higher than the estimated power generation under the working mode before the switching. The negative benefit increment group corresponds to switching events with net energy consumption. As can be seen from the figure, the positive benefit increment samples are concentrated in the range of 5Wh to 20Wh, while the negative benefit increment samples are concentrated to the left of the zero-value baseline. The number of positive samples is significantly greater than the number of negative samples, which verifies the conclusion that the vast majority of area switching events themselves have net output electrical energy.

[0036] In one specific embodiment, step S4 includes: The switching benefit increment is compared with the difference in wave energy conversion efficiency before and after the switching to obtain the switching benefit determination result. Based on the switching benefit determination results, the slit wave energy spectrum width parameter and slit wavefront amplification factor corresponding to the triggering of this surface switching command are respectively assigned to the positive switching sample set or the negative switching sample set to obtain the threshold correction sample set. Based on the threshold correction sample set, the preset threshold for spectral width and the preset threshold for amplification factor are iteratively corrected in the tightening or expanding direction with a fixed step size to obtain the updated preset threshold for spectral width and the updated preset threshold for amplification factor. The updated spectral width preset threshold and the updated amplification factor preset threshold are written into the surface shape switching instruction generation rule to obtain the updated surface shape switching instruction generation rule.

[0037] Specifically, the joint comparison of the modal conversion benefit increment and the difference in wave energy conversion efficiency before and after the switch is performed according to the following rules: The difference in wave energy conversion efficiency before and after the switch is obtained by subtracting the wave energy conversion efficiency in the first complete statistical window after the switch is completed from the wave energy conversion efficiency in the most recent complete statistical window before the switch. The wave energy conversion efficiency is calculated by dividing the average output power of the power output device by the product of the incident wave power density and the buoy's wave-facing width. The incident wave power density is obtained by using the standard spectral moment formula from the effective wave height and energy period of the incident reference wave surface sequence. When the difference in wave energy conversion efficiency before and after the switch is greater than zero and the modal conversion benefit increment is greater than zero, the joint comparison result is positive, and a positive switch benefit judgment result is output; when the difference in wave energy conversion efficiency before and after the switch is less than zero or the modal conversion benefit increment is less than zero, the joint comparison result is negative, and a negative switch benefit judgment result is output. Based on the switching benefit determination results, the slit wave energy spectrum width parameter recorded when the surface switching command is triggered will be assigned to either the positive switching sample set or the negative switching sample set. The corresponding slit wavefront amplification factor will be assigned to the corresponding sample set simultaneously. The two sample sets will then be combined to form the threshold correction sample set.

[0038] Iterative corrections are performed on the preset threshold for spectral width and the preset threshold for amplification factor based on a threshold correction sample set: When the results of three consecutive switching benefit determinations are all positive, the mean value of the spectral width parameter of the three most recent narrow-slit waves in the positive switching sample set is calculated, and the preset threshold for spectral width is expanded once in the direction of this mean value with a fixed step size of 0.02. The fixed step size of 0.02 is to ensure that the threshold adjustment granularity is fine enough to avoid over-adjustment; when the results of two consecutive switching benefit determinations are both negative, the preset threshold for spectral width is corrected once in the tightening direction with a fixed step size of 0.02. The allowable adjustment range of the preset threshold for spectral width is limited to 0.20 to 0.50. When it exceeds the boundary, it is locked at the boundary value. The boundary value is determined based on the physical boundary of the effective range of narrow-slit resonance. When it is below 0.20, the narrow-slit resonance condition is extremely difficult to meet. When it is above 0.50, the probability of broadband dispersed sea state being misjudged as the resonance gain range increases significantly. The correction rule for the preset threshold for amplification factor is exactly the same as that for the preset threshold for spectral width, with a fixed step size of 0.05 and an allowable adjustment range of 1.10 to 1.50. The updated spectral width preset threshold and the updated amplification factor preset threshold are synchronously written into the surface switching instruction generation rule, replacing the original threshold pair. This allows the logic AND operation of the next control cycle to be executed based on the updated decision boundary, resulting in the updated surface switching instruction generation rule.

[0039] The above describes the float-type wave energy device and the floating breakwater narrow slot resonance enhancement method in the embodiments of this application. The following describes the float-type wave energy device and the floating breakwater narrow slot resonance enhancement system in the embodiments of this application. One embodiment of the float-type wave energy device and the floating breakwater narrow slot resonance enhancement system in the embodiments of this application includes: The acquisition module is used to acquire the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater, and obtain the narrow gap wave series; The generation module is used to perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor, and generate a surface shape switching command based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds. The trigger module is used to trigger the WEC float to rotate around the vertical axis according to the surface shape switching command, interchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side, and convert the transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation into electrical energy through the power output device to obtain the modal conversion benefit increment. The correction module is used to combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after the switching, and to iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

[0040] This invention also provides a float-type wave energy device and a floating breakwater narrow-slot resonance enhancement device, which can be a server. The float-type wave energy device and floating breakwater narrow-slot resonance enhancement device include a processor, memory, display screen, input device, network interface, and database connected via a system bus. The processor, designed as a computer, provides computing and control capabilities. The memory of the float-type wave energy device and floating breakwater narrow-slot resonance enhancement device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the float-type wave energy device and floating breakwater narrow-slot resonance enhancement device stores the data corresponding to this embodiment. The network interface of the float-type wave energy device and floating breakwater narrow-slot resonance enhancement device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the above-described method.

[0041] The present invention also provides a computer-readable storage medium, which can be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when the instructions are executed on a computer, cause the computer to perform the steps of the floating wave energy device and the floating breakwater narrow slot resonance enhancement method.

[0042] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0043] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a float-type wave energy device and a floating breakwater narrow-slot resonance enhancement device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A float-type wave energy device and a method for enhancing the resonance effect of a narrow slot in a floating breakwater, characterized in that, The method includes: Step S1: Collect the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater to obtain the narrow gap wave series; Step S2: Perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor. Based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds, generate a surface shape switching command. Step S3: According to the surface shape switching command, trigger the WEC float to rotate around the vertical axis, and exchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side. The transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation is converted into electrical energy through the power output device to obtain the modal conversion benefit increment. Step S4: Combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after switching, and iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

2. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 1, characterized in that, Step S1 includes: In the narrow gap water area between the WEC buoy and the floating breakwater, several capacitive wavefront sensors are arranged at equal intervals along the direction of incident wave propagation. The instantaneous water level rise time series collected by each sensor is spatially averaged to obtain the representative wavefront sequence of the narrow gap. Based on the narrow slit representative wavefront sequence, a rolling truncation process is performed with a fixed statistical window length and a fixed sliding step size to obtain the narrow slit wavefront sequence.

3. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 1, characterized in that, Step S2 includes: After applying Hanning window weighting to the narrow slit wavefront sequence, a fast Fourier transform is performed to obtain the narrow slit wave energy density spectrum. Based on the energy density spectrum of the slit wave, the zero-order spectral moment, the second-order spectral moment, and the fourth-order spectral moment are calculated respectively. The spectral width is calculated based on the zero-order spectral moment, the second-order spectral moment, and the fourth-order spectral moment to obtain the energy spectral width parameter of the slit wave. The slit wavefront magnification factor is obtained by taking the square root of the ratio between the zero-order spectral moment of the energy density spectrum of the slit wave and the zero-order spectral moment of the incident reference wavefront sequence. The slit wave energy spectrum width parameter is compared with a preset threshold for spectrum width, and the slit wavefront amplification factor is compared with a preset threshold for amplification factor. Based on the two comparison results, a logical AND operation is performed to obtain the surface shape switching command.

4. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 1, characterized in that, In step S3, triggering the WEC float to rotate around the vertical axis according to the surface shape switching command includes: The surface shape switching command is compared with the surface shape switching command of the previous control cycle to obtain the modal change trigger signal; Based on the modal change trigger signal, the anti-shake timing process is started, and the surface shape switching command is continuously verified for consistency within a fixed anti-shake delay time to obtain a switching confirmation command. According to the switching confirmation command, the rotational degree of freedom locking mechanism is unlocked in sequence, the stepper motor is driven to rotate at a fixed angle, and the rotational degree of freedom locking mechanism is relocked to obtain the cross-section interchange state.

5. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 4, characterized in that, In step S3, the symmetrical cross-section of the WEC buoy and the asymmetrical triangular baffle cross-section are interchanged on the breakwater-facing side, including: Based on the aforementioned cross-section interchange state, when the symmetrical cross-section of the WEC float is switched to the side facing the breakwater, a symmetrical oscillating resonance water area is formed between the narrow slit water body and the symmetrical cross-section. Based on the aforementioned cross-section interchange state, when the asymmetric triangular baffle cross-section of the WEC float is switched to face the breakwater side, the lower edge of the asymmetric triangular baffle cross-section extends to a fixed draft ratio below the still water surface, forming an asymmetric guiding water area between it and the narrow slit water body. Based on the current activation state of the symmetrical oscillating resonance water area and the asymmetrical guiding water area, the current working state of the cross section is determined, and the working identifier of the cross section is obtained.

6. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 5, characterized in that, In step S3, the transient hydrodynamic excitation generated by the narrow slit water body on the float during rotation is converted into electrical energy via a power output device to obtain the modal conversion benefit increment, including: Based on the cross-sectional working mark, during the rotation of the WEC float, the transient hydrodynamic excitation is collected and processed in real time by a triaxial force sensor to obtain a vertical transient excitation force sequence. The vertical transient excitation force sequence and the float heave velocity sequence are input into the power output device for electromechanical conversion to obtain the transient power generation within the rotation cycle. The difference between the transient power generation during the rotation cycle and the estimated power generation during the corresponding time period under the working mode before the switch is processed to obtain the mode conversion benefit increment.

7. The float-type wave energy device and the floating breakwater narrow-slot resonance enhancement method according to claim 1, characterized in that, Step S4 includes: The switching benefit increment is compared with the difference in wave energy conversion efficiency before and after the switching to obtain the switching benefit determination result. Based on the switching benefit determination result, the slit wave energy spectrum width parameter and slit wavefront amplification factor corresponding to the triggering of this surface switching command are respectively assigned to the positive switching sample set or the negative switching sample set to obtain the threshold correction sample set. Based on the threshold correction sample set, the preset threshold for spectral width and the preset threshold for amplification factor are iteratively corrected in the tightening or expanding direction with a fixed step size to obtain the updated preset threshold for spectral width and the updated preset threshold for amplification factor. The updated spectral width preset threshold and the updated amplification factor preset threshold are written into the surface shape switching instruction generation rule to obtain the updated surface shape switching instruction generation rule.

8. A float-type wave energy device and a floating breakwater narrow-slot resonance enhancement system, characterized in that, For implementing the method of enhancing the resonance effect of the float-type wave energy device and the narrow slot resonance effect of the floating breakwater as described in any one of claims 1-7, the float-type wave energy device and the narrow slot resonance effect of the floating breakwater system comprises: The acquisition module is used to acquire the wave rise time series in the narrow gap water area between the WEC buoy and the floating breakwater, and obtain the narrow gap wave series; The generation module is used to perform spectral analysis on the narrow slit wavefront sequence to obtain the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor, and generate a surface shape switching command based on the comparison results of the narrow slit wave energy spectrum width parameter and the narrow slit wavefront amplification factor with their respective preset thresholds. The trigger module is used to trigger the WEC float to rotate around the vertical axis according to the surface shape switching command, interchange the symmetrical section and the asymmetrical triangular baffle section of the WEC float between the breakwater side, and convert the transient hydrodynamic excitation generated by the narrow slit water on the float during the rotation into electrical energy through the power output device to obtain the modal conversion benefit increment. The correction module is used to combine the modal conversion benefit increment with the difference in wave energy conversion efficiency before and after the switching, and to iteratively correct the preset threshold to obtain the updated surface switching instruction generation rule.

9. A float-type wave energy device and a floating breakwater narrow-slot resonance enhancement device, characterized in that, The device includes a memory and a processor, the memory storing a computer program that can run on the processor, and the processor executing the computer program to implement the method for enhancing the resonance of the float-type wave energy device and the narrow slot of the floating breakwater as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, the processor executes the method for enhancing the resonance effect of the float-type wave energy device and the narrow slot of the floating breakwater as described in any one of claims 1 to 7.

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