Heaving type double-body wave energy conversion device and control method

Abstract

The invention discloses a heaving type double-body wave energy conversion device and a control method. The heaving type double-body wave energy conversion device comprises buoys and energy capturing rods. The buoy comprises a buoy shell and a buoy internal structure arranged in an inner cavity of the buoy shell. The buoy internal structure comprises a power generation system, a speed increasing mechanism, a main shaft, a data acquisition mechanism, a rigidity adjusting system and a control system; a connecting rope is wound on the main shaft and penetrates through the buoy shell to be connected with an energy harvesting rod; the energy harvesting rod sinks in water, waves in the water impact the energy harvesting rod, the energy harvesting rod drags the connecting rope under the impact of the waves, the main shaft rotates in a reciprocating mode, and the main shaft drives the power generation system to be charged through the speed increasing mechanism; the data collecting mechanism is used for collecting wave parameters and main shaft parameters, the control system is used for calculating the rigidity value of the wave energy conversion device and the PTO damping value of the power generation system according to the wave parameters, and the control system adjusts the torque of the main shaft through the rigidity adjusting system according to the calculated rigidity value of the wave energy conversion device. And adjusting the output power of the power generation system according to the PTO damping value.

Description

Technical Field

[0001] The invention relates to a heaving type twin-body wave energy conversion device and a control method, belonging to the field of wave energy power generation. Background Art

[0002] The ocean is Earth's largest untapped energy reservoir, containing numerous forms of renewable energy, including tidal energy, temperature gradient energy, salinity gradient energy, tide energy, and wave energy. Wave energy, among others, holds the greatest potential and represents the most significant form of marine energy. As a renewable marine energy source, wave energy is clean and pollution-free, boasting vast reserves and high resource availability. Its development and utilization can effectively reduce dependence on traditional fossil fuels, significantly mitigating energy supply risks. The development of wave energy holds crucial strategic significance for optimizing the energy mix, protecting the ecological environment, and promoting sustainable development of the marine economy.

[0003] The conversion of wave energy into usable electrical energy is accomplished by wave power generation devices through a series of processes, including wave energy capture, absorption, conversion, and storage. This process can be divided into three steps: the first step is to convert the periodic oscillation of the waves into reciprocating linear motion or reciprocating rotational motion; the second step is to convert the reciprocating motion into low-speed continuous rotational motion using hydraulics, accumulators, or springs; and the third step is to convert the low-speed continuous rotational motion into high-speed continuous motion compatible with the generator through hydraulic (pneumatic) or mechanical systems. Different types of wave power generation devices have different technical principles. Depending on the energy capture system, wave power generation devices can be divided into oscillating water column type, oscillating float type, overriding wave type (contracting wave channel type), pendulum type, etc.

[0004] There is also a wave energy conversion device combined with an offshore buoy in the prior art. Summary of the Invention

[0005] The present invention provides a heaving type twin-body wave energy conversion device and a control method, which solve the problems disclosed in the background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A vertical swing catamaran wave energy conversion device comprises a buoy and an energy harvesting rod; the buoy comprises a buoy shell and an internal buoy structure arranged in the inner cavity of the buoy shell; the internal buoy structure comprises a power generation system, a speed increasing mechanism, a main shaft, a data acquisition mechanism, a stiffness adjustment system and a control system; a connecting rope is wound around the main shaft, and the connecting rope passes through the buoy shell to connect to the energy harvesting rod; the energy harvesting rod is submerged in water, and waves in the water impact the energy harvesting rod, and the energy harvesting rod pulls the connecting rope under the impact of the waves, causing the main shaft to rotate back and forth, and the main shaft drives the power generation system to be charged through the speed increasing mechanism; the data acquisition mechanism is used to collect wave parameters and main shaft parameters, and the control system is used to calculate the stiffness value of the wave energy conversion device and the PTO damping value of the power generation system according to the wave parameters, and the control system adjusts the torque of the main shaft through the stiffness adjustment system according to the calculated stiffness value of the wave energy conversion device, and adjusts the output power of the power generation system according to the PTO damping value.

[0008] Furthermore, a wire pulley device is provided inside and outside the buoy shell where the connecting rope passes through, and the wire pulley device includes a wire pulley fixing disk, a wire pulley stator and a wire pulley rotor; the wire pulley fixing disk is connected to the buoy shell, and the wire pulley rotor is rotatably connected to the wire pulley fixing disk through the wire pulley stator, and the wire pulley rotor is distributed on both sides of the connecting rope.

[0009] Furthermore, the speed increasing mechanism includes a large speed increasing gear and a small speed increasing gear that are meshed with each other; the large speed increasing gear is coaxially connected to the main shaft, and the small speed increasing gear is connected to the power generation system.

[0010] Furthermore, the power generation system includes a battery, a generator, a rectifier and a buck-boost converter; the speed increasing pinion is connected to the generator, the speed increasing pinion drives the generator, the generator converts AC power into DC power through the rectifier, and then transmits the DC power to the battery through the buck-boost converter.

[0011] Furthermore, the stiffness adjustment system includes a hysteresis brake, which is connected to the main shaft via a coupling, and the hysteresis brake is used to output torque to the main shaft.

[0012] Furthermore, the data acquisition mechanism includes an angular velocity sensor and a MEMS sensor; the angular velocity sensor is used to measure the position angle of the main shaft, and the MEMS sensor is used to collect wave information.

[0013] Furthermore, it also includes a data transmission module and a communication antenna, and the data transmission module is used to establish communication with the host computer through the communication antenna.

[0014] Furthermore, the stiffness value of the wave energy conversion device is converted into the inherent damping of the wave energy conversion device. The inherent damping is calculated by taking the weighted average inherent damping of k waves. ;ω is the frequency, is the weight coefficient of the corresponding wave.

[0015] Furthermore, the method for calculating the PTO damping value of the power generation system is as follows: let the optimal damping of the power generation system be equal to the inherent damping of the wave energy conversion device , PTO damping value of the power generation system ; is the permanent magnet flux; is the q-axis current; Pn is the number of rotor pole pairs; is the speed increasing ratio of the two-stage speed increasing mechanism.

[0016] Furthermore, the method for adjusting the output power of the power generation system according to the PTO damping value is as follows:

[0017] By controlling the q-axis current of the power generation system, the damping of the power generation system is matched with the inherent damping of the wave energy conversion device. Using id = 0 as the d-axis current control target to achieve static decoupling of the d and q axis currents, the basic conditions for amplitude control are:

[0018] ;

[0019] The dq axis current is adjusted to track the maximum power point of the power generation system.

[0020] The beneficial effects achieved by the present invention are:

[0021] 1. The heaving catamaran wave energy conversion device of the present invention can be widely used in marine related industries as a marine navigation buoy, ocean observation buoy, etc.

[0022] 2. The energy capture rod is completely immersed in water, which can increase the system inertia and improve the energy capture width without reducing the wave excitation force and radiation force.

[0023] 3. The hysteresis brake can achieve stepless torque adjustment and can be used as an overload protection in harsh wave environments

[0024] 4. The vertical swing catamaran wave energy conversion device can be connected to a deployable seabed anchor point or directly deployed in the target sea area, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the heaving catamaran wave energy conversion device of the present invention;

[0026] Figure 2 This is a schematic diagram of the buoy structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the internal structure of the buoy of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the upper guide wheel inside the buoy of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the lower guide wheel in the buoy of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the speed increasing mechanism in the buoy of the present invention;

[0031] Figure 7 Schematic diagram of the hardware topology of the power generation system of the present invention;

[0032] Figure 8 This is a block diagram of the maximum power point tracking control strategy of the present invention.

[0033] Figure 9 Schematic diagram of the hardware topology of the power generation system of the present invention;

[0034] In the figure, 1 is the buoy, 2 is the connecting rope, 3 is the energy capture rod, 4 is the buoy shell, 5 is the internal structure of the buoy, 6 is the battery, 7 is the control system, 8 is the support clamp, 9 is the frame, 10 is the data transmission module, 11 is the motor bracket, 12 is the generator, 13 is the speed increasing gear, 14 is the hysteresis brake, 15 is the coupling, 16 is the main shaft, 17 is the support bearing, 18 is the communication antenna, 19 is the angle sensor, 20 is the upper wire pulley fixing plate, 21 is the upper wire pulley stator, 22 is the upper wire pulley rotor, 23 is the lower wire pulley fixing plate, 24 is the lower wire pulley stator, 25 is the lower wire pulley rotor, and 26 is the speed increasing pinion. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0036] Example 1:

[0037] like Figure 1 As shown, this embodiment provides a heave-type catamaran wave energy conversion device, comprising a buoy 1 and an energy capture rod 3 connected by a connecting rope 2;

[0038] like Figure 2 As shown, the buoy 1 includes a buoy shell 4 and a buoy internal structure 5 provided in the inner cavity of the buoy shell 4;

[0039] like Figure 3 、 Figure 6As shown, the internal structure 5 of the buoy includes a power generation system, a speed increasing mechanism, a main shaft 16, a data acquisition mechanism, a stiffness adjustment system and a control system 7; a connecting rope 2 is wound around the main shaft 16, and the connecting rope 2 passes through the buoy shell 4 to connect to the energy capture rod 3; the energy capture rod 3 is submerged in the water, and the waves in the water impact the energy capture rod 3, and the energy capture rod 3 pulls the connecting rope 2 under the impact of the waves, so that the main shaft 16 rotates back and forth, and the main shaft 16 drives the power generation system to charge through the speed increasing mechanism; the data acquisition mechanism is used to collect wave parameters and main shaft 16 parameters, and the control system 7 is used to calculate the stiffness value of the wave energy conversion device and the PTO damping value of the power generation system according to the wave parameters, and the control system 7 adjusts the torque of the main shaft 16 through the stiffness adjustment system according to the calculated stiffness value of the wave energy conversion device, and adjusts the output power of the power generation system according to the PTO damping value. The stiffness adjustment system includes a hysteresis brake 14, which is connected to the main shaft 16 via a coupling 15 and is used to output torque to the main shaft 16. The speed-increasing mechanism includes a meshing speed-increasing gear 13 and a speed-increasing pinion 26; the speed-increasing gear 13 is coaxially connected to the main shaft 16, and the speed-increasing pinion 26 is connected to the power generation system. The data transmission module 10 and the communication antenna 18 are used to establish communication with the host computer via the communication antenna 18, facilitating monitoring of the entire device's operating status and facilitating device software upgrades.

[0040] The data acquisition mechanism includes an angular velocity sensor 19 and a MEMS sensor; the angular velocity sensor 19 is used to measure the position angle of the main shaft 16, and the MEMS sensor is used to collect wave energy information.

[0041] Preferably, the speed-increasing gear 13, the hysteresis brake 14, the coupling 15, and the communication antenna 18 are all arranged on the frame 9; the main shaft 16 is arranged on the frame 9 through the support bearing 17; the power generation system includes a generator 12, and the generator 12 is arranged on the motor bracket 11.

[0042] like Figure 4 and Figure 5As shown, the buoy housing 4 is provided with pulley devices both inside and outside the portion through which the connecting rope 2 passes. Two pulley devices, upper and lower, are mounted on the buoy housing 4. The upper pulley device includes an upper pulley fixing plate 20, an upper pulley stator 21, and an upper pulley rotor 22. The lower pulley device includes a lower pulley fixing plate 23, a lower pulley stator 24, and a lower pulley rotor 25. The connecting rope 2 wound from the main shaft 16 is restrained by the upper pulley rotor 22 and will not rub against the inner wall of the buoy housing 4. The connecting rope 2 in the lower pulley device at the bottom of the buoy is also restrained by the four lower pulley rotors 25 and will not rub against the bottom of the buoy. The upper and lower pulley devices are mounted at the top and bottom of the buoy housing 4, respectively, to ensure that the connecting rope 2 remains vertically aligned and prevents it from rubbing against the inner wall of the buoy housing 4.

[0043] like Figure 7 As shown, the power generation system includes a battery 6, a generator 12, a rectifier and a buck-boost converter; the speed increasing pinion 26 is connected to the generator 12, and the speed increasing pinion 26 drives the generator 12. The generator 12 converts AC power into DC power through the rectifier, and then transmits the DC power to the battery 6 through the buck-boost converter. The battery 6 supplies power to the entire wave energy conversion device.

[0044] It should be noted that the hardware structures of the present invention are all provided with waterproof measures for underwater operation.

[0045] Example 2:

[0046] This embodiment provides a control method for the heave-type catamaran wave energy conversion device described in Example 1, comprising the following steps:

[0047] Real-time monitoring of device status parameters, including motor speed, spindle rotation angle, hysteresis brake torque, battery power, etc.

[0048] The power generation efficiency of the device is calculated based on the main shaft rotation angle collected by the angle sensor and combined with a preset calculation model.

[0049] When changes in wave intensity are detected, the control system adjusts the hysteresis brake torque according to a pre-set control strategy. If wave intensity increases, the hysteresis brake torque is increased to increase resistance to spindle rotation, preventing damage to the device caused by excessive speed. If wave intensity decreases, the hysteresis brake torque is reduced to improve energy conversion efficiency.

[0050] The data transmission module promptly transmits collected sensor data to the host computer, which analyzes and processes the data, generates status reports and optimization suggestions, and feeds them back to the control system. Based on this feedback, the control system further optimizes the device's operating parameters to achieve efficient and stable conversion of wave energy.

[0051] MEMS sensors are used to measure the three-axis acceleration of the device to calculate the wave information.

[0052] Mainly includes the control of hysteresis brake:

[0053] An adaptive fuzzy-PID control algorithm is used to adjust the hysteresis brake torque based on predicted wave conditions and current device operating parameters. The fuzzy control rule base dynamically adjusts the proportional (P), integral (I), and differential (D) parameters of the PID controller based on the deviation and rate of change between wave intensity (assessed by parameters such as wave height and period) and the spindle speed. When wave intensity is predicted to increase and the spindle speed deviation is large, the proportional parameter is increased for a faster response, while the integral and differential parameters are adjusted simultaneously to prevent system overshoot. This allows for precise regulation of the hysteresis brake torque, ensuring stable operation and maximum energy capture in strong waves.

[0054] like Figure 8 As shown, the MEMS sensor collects wave information including wave acceleration, calculates the stiffness value of the wave energy conversion device and the optimal PTO damping of the power generation system, adjusts the stiffness of the system by the variable stiffness system, and adjusts the optimal PTO damping by the power generation system using the maximum power point tracking control strategy. Then, the power management strategy, DC bus voltage regulation control strategy and coordinated control strategy are adopted to ensure the stable operation of the system.

[0055] When the frequency of the incident wave changes, the wave energy capture device needs to be controlled. The variable stiffness mechanism changes the device's stiffness by varying the torque of the hysteresis brake, thereby changing the device's natural frequency to align with the incoming wave frequency, achieving resonance and, in other words, frequency control. However, this only satisfies the phase condition. To achieve maximum system power output, the amplitude condition must also be met. This means controlling the damping of the power generation system to match the inherent damping of the wave energy conversion device, thereby maximizing the conversion of mechanical energy into electrical energy. Combining these two factors enables maximum power point tracking and achieves maximum power output.

[0056] According to the hydrodynamic equation of the wave energy system in the time domain, the hydrodynamic motion equation of the system in the frequency domain can be obtained as follows:

[0057]

[0058] ω is the frequency of the wave, is the main shaft moment of inertia, ) is the additional mass, is the radiation damping, is the recovery stiffness, is the angular displacement, is the wave excitation torque, M PTO (ω) is the damping torque of the power generation system;

[0059] When the angular velocity of the wave energy generation system is recorded as , then the above formula can be expressed as:

[0060]

[0061] Where j represents the unit in the complex number;

[0062] According to the relationship between the inherent impedance of the wave energy device and the external force and speed, the inherent impedance of the device can be obtained as:

[0063]

[0064] Where R m (ω) and X m (ω) represent the equivalent resistance and equivalent reactance of the wave energy generation system respectively.

[0065] According to the inherent impedance of the device, the inherent damping of the wave energy conversion device can be obtained as follows:

[0066]

[0067] The damping torque of the power generation system is expressed in the frequency domain as:

[0068]

[0069] According to the amplitude condition of maximum power point tracking, the PTO damping of the power generation system needs to be equal to the inherent damping of the wave energy device, so:

[0070]

[0071] According to the frequency control strategy, the natural frequency of the wave energy device matches the peak frequency of the wave. When the wave is a regular wave, the frequency of the wave is ω, and we can get:

[0072]

[0073] After substitution, the damping of the PTO system can be obtained as:

[0074]

[0075] Therefore, under regular waves, when the damping of the PTO system is equal to the radiation damping of the wave energy power generation device, the wave energy power generation system can meet the amplitude condition and achieve maximum power output. At this time, the angular velocity of the wave energy power generation system is:

[0076]

[0077] Then the maximum average power output of the wave energy system under regular waves is:

[0078]

[0079] Since ocean waves are irregular, they are composed of regular waves of different frequencies and amplitudes. For the frequency control strategy, since the wave energy generation device can only resonate with a specific frequency at any time, the present invention selects the peak frequency of the wave spectrum as the resonant frequency, because the wave energy at the peak frequency is the largest. For the amplitude control strategy, the inherent damping of the wave energy generation system cannot be directly solved. Although the inherent damping of the device at a single wave frequency can be obtained by formula (1.4), the inherent damping of the device under the action of waves of multiple frequencies is unknown. The present invention proposes a weighted average method to approximate the inherent damping of the wave energy generation system under the action of irregular waves. Using this method, the inherent damping of the wave energy generation system under irregular waves can be obtained as:

[0080]

[0081] Therefore, according to the amplitude condition, the optimal damping of the power generation system is equal to the inherent damping of the wave energy conversion device. Then, under irregular wave conditions, the amplitude condition for the power generation system to achieve maximum power point tracking is:

[0082]

[0083] Since the power generation system adjusts the damping of the PTO system by controlling the damping torque of the generator, it can be obtained:

[0084]

[0085] is the permanent magnet flux, is the q-axis current, Pn is the number of rotor pole pairs, is the speed increasing ratio of the two-stage speed increasing mechanism;

[0086] According to the above formula, we can get:

[0087]

[0088] Therefore, by controlling the q-axis current of the generator, the damping of the PTO system can be matched with the inherent damping of the wave energy generation system. In addition, in order to achieve static decoupling of the d-axis and q-axis currents, id = 0 is generally used as the d-axis current control target. Therefore, the basic conditions for achieving amplitude control are:

[0089]

[0090] Therefore, the block diagram of the maximum power point tracking control strategy is as follows Figure 9 As shown in FIG, the maximum power point tracking can be achieved by adjusting the dq axis current according to the above conditions.

[0091] SVPWM: Space Vector Pulse Width Modulation. The core goal is to control the switching state of the inverter to make the output voltage as close to an ideal sine wave as possible, thereby achieving efficient operation and precise control of the motor.

[0092] PMSM: Permanent Magnet Synchronous Motor. The core feature is the use of permanent magnets as part of the rotor to generate the magnetic field.

[0093] i a 、i b 、i c are the phase currents of the three-phase windings, i d 、i q is the current of d-axis and q-axis, R d 、R q is the stator armature resistance of the d-axis and q-axis, ω e is the rotor electrical angular velocity, L d , L q is the synchronous inductance of the d-axis and q-axis.

[0094] Control target on the motor side: Through current and voltage closed-loop control, the motor can run stably in the target state (speed, torque, etc.)

[0095] The control goal of the system side: Combined with the MPPT module, it tracks the maximum power point of wave energy and maximizes energy utilization efficiency.

[0096] 1. Signal detection and conversion

[0097] Current detection (i a 、i b 、i c ): Collect the three-phase stator current of the motor, and convert it into i which is easy to control through abc→αβ (Clark transformation) and αβ→dq (Park transformation). dDirect axis current, quadrature axis current i q (DC component in synchronous rotating coordinate system, simplifying control logic).

[0098] Speed / position (ω, θ): Usually obtained by an encoder or a sensorless algorithm, it is used for angular orientation in Park transform to ensure that the current vector is precisely aligned with the motor magnetic field.

[0099] 2. MPPT module

[0100] According to the wave energy characteristics (such as wave frequency and wave height), the reference current i is calculated and output q,ref 、i d,ref (or speed and other instructions) to make the system work in the optimal state of energy utilization (such as wave energy tracking maximum power capture point).

[0101] 3. Current closed-loop controller (PI regulator)

[0102] i d 、i q Closed loop: The detected i d 、i q Compared with the reference value, the error is calculated by the PI regulator and the output voltage is compensated ΔU d , ΔU q .

[0103] Voltage feedforward compensation: Introducing the motor mathematical model term (R d i d 、R q i q Stator resistance voltage drop; ω e Back electromotive force; ω e i q L q Cross-coupling term), compensates for the motor’s internal voltage changes in advance and improves control response speed.

[0104] 4. Voltage conversion and drive

[0105] dq→αβ, SVPWM: closed-loop output U d 、U q After the dq→αβ inverse transformation back to the stationary coordinate system, the switching signal is generated through space vector pulse width modulation (SVPWM) to drive the inverter (power module on the right) to output three-phase voltage and control the operation of the motor.

[0106] The overall logic is: wave energy is calculated through MPPT to obtain the optimal reference instruction → the motor current / voltage closed-loop quickly tracks the instruction → precise drive is achieved through coordinate transformation and SVPWM → ultimately the motor is allowed to operate stably in a state of maximized energy utilization while meeting operating requirements such as speed and torque.

[0107] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0108] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A heaving catamaran wave energy conversion device, characterized in that: The invention comprises a buoy (1) and an energy capture rod (3); the buoy (1) comprises a buoy shell (4) and a buoy internal structure (5) arranged in the inner cavity of the buoy shell (4); the buoy internal structure (5) comprises a power generation system, a speed increasing mechanism, a main shaft (16), a data acquisition mechanism, a stiffness adjustment system and a control system (7); a connecting rope (2) is wound around the main shaft (16), and the connecting rope (2) passes through the buoy shell (4) and is connected to the energy capture rod (3); the energy capture rod (3) is sunk in the water, and waves in the water impact the energy capture rod (3), and the energy capture rod (3) is moved by the waves. The connecting rope (2) is pulled under the impact, causing the main shaft (16) to reciprocate, and the main shaft (16) drives the power generation system to be charged through the speed increasing mechanism; the data acquisition mechanism is used to collect wave parameters and main shaft (16) parameters, and the control system (7) is used to calculate the stiffness value of the wave energy conversion device and the PTO damping value of the power generation system according to the wave parameters; the control system (7) adjusts the torque of the main shaft (16) through the stiffness adjustment system according to the calculated stiffness value of the wave energy conversion device, and adjusts the output power of the power generation system according to the PTO damping value.

2. The heaving catamaran wave energy conversion device according to claim 1, characterized in that: The buoy shell (4) is provided with a wire pulley device inside and outside the portion where the connecting rope (2) passes through, and the wire pulley device includes a wire pulley fixing disk, a wire pulley stator and a wire pulley rotor; the wire pulley fixing disk is connected to the buoy shell (4), and the wire pulley rotor is rotatably connected to the wire pulley fixing disk through the wire pulley stator, and the wire pulley rotor is distributed on both sides of the connecting rope (2).

3. The heaving catamaran wave energy conversion device according to claim 1, characterized in that: The speed increasing mechanism comprises a large speed increasing gear (13) and a small speed increasing gear (26) that are meshed with each other; the large speed increasing gear (13) is coaxially connected to the main shaft (16), and the small speed increasing gear (26) is connected to the power generation system.

4. The heaving catamaran wave energy conversion device according to claim 3, characterized in that: The power generation system includes a battery (6), a generator (12), a rectifier and a buck-boost converter; the speed increasing pinion (26) is connected to the generator (12), the speed increasing pinion (26) drives the generator (12), and the generator (12) converts AC power into DC power through the rectifier, and then transmits the DC power to the battery (6) through the buck-boost converter.

5. The heaving catamaran wave energy conversion device according to claim 1, characterized in that: The stiffness adjustment system comprises a hysteresis brake (14), wherein the hysteresis brake (14) is connected to a main shaft (16) via a coupling (15), and the hysteresis brake (14) is used to output torque to the main shaft (16).

6. The heaving catamaran wave energy conversion device according to claim 1, characterized in that: The data acquisition mechanism comprises an angular velocity sensor (19) and a MEMS sensor; the angular velocity sensor (19) is used to measure the position angle of the main shaft (16), and the MEMS sensor is used to collect wave information.

7. The heaving catamaran wave energy conversion device according to claim 1, characterized in that: It also includes a data transmission module (10) and a communication antenna (18), wherein the data transmission module (10) is used to establish communication with a host computer via the communication antenna (18).

8. The control method of the heave-type catamaran wave energy conversion device according to claim 1, characterized in that: The stiffness value of the wave energy conversion device is converted into the inherent damping of the wave energy conversion device. The calculation method of the inherent damping is: take the weighted average inherent damping of k waves ;ω is the frequency, is the weight coefficient of the corresponding wave.

9. The control method of the heave type catamaran wave energy conversion device according to claim 8, characterized in that: The method for calculating the PTO damping value of the power generation system is as follows: let the optimal damping of the power generation system be equal to the inherent damping of the wave energy conversion device. , PTO damping value of the power generation system ; is the permanent magnet flux; is the q-axis current; Pn is the number of rotor pole pairs; is the speed increasing ratio of the two-stage speed increasing mechanism.

10. The control method of the heave type catamaran wave energy conversion device according to claim 8, characterized in that: The method for adjusting the output power of the power generation system according to the PTO damping value is: By controlling the q-axis current of the power generation system, the damping of the power generation system is matched with the inherent damping of the wave energy conversion device. The static decoupling of the d-axis and q-axis currents is achieved by using id=0 as the d-axis current control target. The basic conditions for amplitude control are: ； The dq axis current is adjusted to track the maximum power point of the power generation system.

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