Eddy current drive continuously variable speed type tidal current generating set

Abstract

A kind of eddy current drive continuously variable speed type tidal current generating set, belonging to the field of tidal current / ocean current power generation, includes a tidal current impeller, a main transmission shaft, a planetary gear train, an electromagnetic eddy current component and a permanent magnet generator. The tidal current impeller is used to convert the captured ocean current kinetic energy into the mechanical kinetic energy of the planetary gear train. The tidal current impeller is fixedly connected to the main transmission shaft. The main transmission shaft is connected to the input side of the planetary gear train. The output side of the planetary gear train is connected to the copper disk rotor of the electromagnetic eddy current component. The permanent magnet disk rotor of the electromagnetic eddy current component is drivingly connected to the permanent magnet generator through a parallel shaft gear train. The permanent magnet disk rotor and the copper disk rotor can rotate freely relative to each other. The invention is simple, compact, steplessly continuously variable speed, and has high efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of tidal / current power generation, and relates to a vortex-driven continuously variable tidal current power generation unit. Background Art

[0002] 70% of the Earth's surface is covered by the ocean, which harbors huge energy sources. Therefore, effectively developing and utilizing ocean energy resources is an important way for future sustainable development and also an important means to solve potential energy crises. Ocean tidal energy is the kinetic energy generated during the periodic ebb and flow of seawater due to the gravitational pull of the moon. Different from other existing new energy forms, such as wind energy and wave energy, tidal energy has advantages such as high energy density, high predictability, and stability. Therefore, developing and utilizing tidal energy has high economic value and market prospects.

[0003] Tidal current power generation units are important devices for developing and utilizing tidal energy and realizing the conversion of tidal kinetic energy into electrical energy. In the past decade or so, various types of tidal current power generation units have emerged one after another and have gradually been commercialized and produced and applied on a large scale. Existing tidal current power generation units mainly adopt a horizontal axis arrangement to capture and absorb the axially flowing tidal kinetic energy. Existing horizontal axis tidal current power generation units adopt a certain transmission form to achieve the transmission of mechanical kinetic energy and the output of electrical power. The main transmission forms are direct drive with a unit transmission ratio and gearbox speed increase transmission. When direct drive is adopted, the generator is directly connected to the tidal current blade, and the oscillation and load fluctuation of the blade can also be directly transmitted to the generator end. The generators of tidal current power generation units adopting direct drive are usually large in size, have high requirements for reliability and excitation intensity, resulting in a substantial increase in the overall cost of the unit.

[0004] When gearbox transmission is adopted, the rotational speed of the low-speed shaft connected to the blade can be increased through the gearbox and transmitted to the high-speed shaft and the generator end. However, the reliability and durability of the gearbox are important issues that need to be solved. Moreover, the speed increase ratio of the gearbox is fixed and cannot be changed. Therefore, it is relatively difficult to change the overall rotational speed of the unit in real time with the tidal current velocity.

[0005] Another relatively common transmission form is the tidal current power generation unit adopting low-speed hydraulic direct drive. Low-speed hydraulic drive has the advantage of flexible drive and can achieve continuously variable and controllable transmission ratio. However, the main problem of low-speed hydraulic drive is relatively low transmission efficiency, only about 70% or so. Moreover, high-pressure and large-flow hydraulic components for tidal current power generation units require separate design and processing, which also increases the cost and expenditure to a certain extent.

[0006] In summary, the existing transmission methods of various tidal current power generation sets have a series of problems such as low efficiency, fixed transmission ratio, large volume, and high cost. Therefore, there is an urgent need for a transmission method with a compact structure, continuous stepless speed regulation, and high efficiency. Summary of the Invention

[0007] In order to overcome the deficiencies of the existing tidal current power generation methods, such as low efficiency, fixed transmission ratio, large volume, and high cost, the present invention provides a vortex drive stepless speed change type tidal current power generation set with a simple and compact structure, stepless continuous speed change, and high efficiency.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0009] A vortex drive stepless speed change type tidal current power generation set includes a tidal current impeller, a main transmission shaft, a planetary gear train, an electromagnetic vortex assembly, and a permanent magnet generator. The tidal current impeller is used to convert the captured sea flow kinetic energy into the mechanical kinetic energy of the planetary gear train. The tidal current impeller is fixedly connected to the main transmission shaft. The main transmission shaft is connected to the input side of the planetary gear train. The output side of the planetary gear train is connected to the copper disk rotor of the electromagnetic vortex assembly. The permanent magnet disk rotor of the electromagnetic vortex assembly is connected to the permanent magnet generator through a parallel shaft gear train. The permanent magnet disk rotor and the copper disk rotor can rotate freely relative to each other.

[0010] Further, the planetary gear train includes a planetary carrier, a ring gear, planetary gears, and a sun gear. The ring gear is fixed in the housing. The input side of the planetary gear train is the planetary carrier. Planetary gears are installed on the planetary carrier. The planetary gears are simultaneously meshed with the sun gear and the inner ring of the ring gear. The output side of the planetary gear train is the sun gear. The sun gear is used to transfer the mechanical kinetic energy of the impeller to the electromagnetic vortex assembly. Of course, other planetary gear transmission methods can also be used.

[0011] Still further, the parallel shaft gear train includes a front parallel shaft pinion, a front parallel shaft gear, a rear parallel shaft pinion, and a rear parallel shaft gear. The permanent magnet disk rotor of the electromagnetic vortex assembly is connected to the rotating shaft of the front parallel shaft pinion. The front parallel shaft pinion is meshed with the front parallel shaft gear. The front parallel shaft gear is coaxially installed with the rear parallel shaft pinion. The rear parallel shaft pinion and the rear parallel shaft gear are meshed. The rotating shaft of the rear parallel shaft gear is connected to the motor shaft of the permanent magnet generator. Of course, other parallel shaft gear transmission methods can also be used.

[0012] Furthermore, in the electromagnetic eddy current assembly, the permanent disk rotor is composed of permanent magnets arranged alternately in the circumferential direction. During operation, there is a relative speed difference, i.e., slip, between the permanent disk rotor and the copper disk rotor. Then, eddy currents are generated in the copper disk in the alternating magnetic field, and the magnetic field induced by the eddy currents couples with the original magnetic field, thereby generating a magnetic transfer torque, which further drives the permanent disk rotor to rotate in the same direction as the copper disk.

[0013] The present invention adopts a planetary gear train, an electromagnetic eddy current assembly, and a double-series parallel-axis speed-increasing gear train to convert the tidal kinetic energy captured by the tidal current impeller into a relatively stable electric power output. By effectively controlling the internal clearance value of the electromagnetic eddy current assembly, the tidal current impeller can always track the optimal power point under the time-varying tidal current velocity conditions, that is, the tidal current generating set can operate at a high efficiency and the optimal power point state, realizing the capture of the maximum tidal kinetic energy and the output of the optimal power. When the tidal current velocity is higher than the rated value, the electromagnetic eddy current assembly can be effectively controlled to keep the rotational speed and power at the generator end at the rated value, so that the overall output power of the unit is stable.

[0014] The beneficial effects of the present invention are mainly manifested in:

[0015] 1. The tidal current generating set of the present invention can realize the stepless speed control and operation at the optimal power point of the unit by controlling the electromagnetic eddy current assembly, and has a high energy conversion and output efficiency.

[0016] 2. The structure of the tidal current energy generating set of the present invention is relatively simple and compact, easy to install, and has a relatively low overall operation cost. The transmission shaft allows a large installation alignment error and can realize non-contact connection, which can effectively reduce and eliminate the vibration and load transmission between the tidal current impeller and the generator, and can effectively reduce the impact of instantaneous high tidal current loads.

[0017] 3. The electromagnetic eddy current assembly adopted by the present invention can realize the soft start and soft stop of the generator, realize the overload protection of the generator, and protect the motor from damage.

[0018] 4. It has a relatively prominent high-efficiency energy-saving effect. Unlike low-speed hydraulic transmission that generally requires a high-energy-consuming hydraulic source, only a limited electromagnetic energy input is required to realize the stepless speed operation of the whole unit, and it can achieve progressive and smooth flexible operation and precise speed regulation and power control for various generators and tidal current impeller loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall structural schematic diagram of the present invention;

[0020] Figure 2 is the schematic diagram of the rotational speed control method of the electromagnetic eddy current assembly of the present invention;

[0021] Figure 3 It is the control schematic diagram of a proportional-integral controller and a self-closed-loop controller.

[0022] The reference numerals are as follows: 1 - tidal current impeller, 2 - main transmission shaft, 3 - planet carrier, 4 - ring gear, 5 - planet gear, 6 - sun gear, 7 - electromagnetic eddy current assembly, 8 - front parallel shaft pinion, 9 - front parallel shaft gear, 10 - rear parallel shaft pinion, 11 - rear parallel shaft gear, 12 - permanent magnet generator. Specific embodiments

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Refer to Figures 1 to 3 , a tidal current power generation unit with an eddy current drive continuously variable speed type, comprising a tidal current impeller 1, a main transmission shaft 2, a planetary gear train, an electromagnetic eddy current assembly 7, and a permanent magnet generator 12,

[0025] The tidal current impeller 1 is used to convert the captured kinetic energy of the sea current into the mechanical kinetic energy of the planetary gear train. The tidal current impeller 1 is fixedly connected to the main transmission shaft 2. The planetary gear train includes a planet carrier 3, a ring gear 4, planet gears 5, and a sun gear 6. The ring gear 4 is fixed in the box body. The main transmission shaft 2 is connected to the planet carrier 5. The planet carrier 5 is provided with planet gears 5. The planet gears 5 are simultaneously meshed with the inner ring of the sun gear 6 and the ring gear 4. The sun gear 6 is used to transfer the mechanical kinetic energy of the impeller to the electromagnetic eddy current assembly 7.

[0026] The rotating shaft of the sun gear 6 is connected to the copper disk rotor of the electromagnetic eddy current assembly 7. The permanent magnet disk rotor of the electromagnetic eddy current assembly 7 is drivingly connected to the permanent magnet generator 12 through a parallel shaft gear train. The permanent magnet disk rotor and the copper disk rotor can rotate relative to each other freely.

[0027] The parallel shaft gear train includes a front parallel shaft pinion 8, a front parallel shaft gear 9, a rear parallel shaft pinion 10, and a rear parallel shaft gear 11. The permanent magnet disk rotor of the electromagnetic eddy current assembly 7 is connected to the rotating shaft of the front parallel shaft pinion 8. The front parallel shaft pinion 8 is meshed with the front parallel shaft gear 9. The front parallel shaft gear 9 and the rear parallel shaft pinion 10 are coaxially installed. The rear parallel shaft pinion 10 and the rear parallel shaft gear 11 are meshed. The rotating shaft of the rear parallel shaft gear 11 is connected to the motor shaft of the permanent magnet generator 12.

[0028] The electromagnetic eddy current assembly 7 of this embodiment is mainly composed of two rotor discs. One part is the permanent magnet disc rotor connected to the front parallel shaft pinion 8, and the permanent magnet disc rotor is composed of permanent magnets arranged alternately in the circumferential direction; the other part is the copper disc rotor connected to the sun gear 6, and the copper disc rotor group runs at the same speed as the sun gear 6. The permanent magnet disc rotor and the copper disc rotor can rotate relative to each other freely. During operation, there is a relative speed difference, that is, slip, between the two, so eddy currents are generated in the copper disc in the alternating magnetic field. According to Lenz's law, the magnetic field induced by the eddy current couples with the original magnetic field, thereby generating a magnetic transmission torque, which in turn drives the permanent magnet disc to rotate in the same direction as the copper disc. When the speed difference between the two decreases to a certain stable value, the magnetic transmission torque generated between the two gradually stabilizes, and finally the two rotor discs operate stably at a certain fixed speed difference, realizing the kinetic energy transmission from the sun gear 6 to the front parallel shaft pinion 8 without mechanical connection. The speed transmitted to the front parallel shaft pinion 8 is increased by two stages through the two-stage parallel shaft gear train before and after, and finally input into the permanent magnet generator 12 to achieve electric power output.

[0029] The eddy current mechanism of the electromagnetic eddy current assembly 7 of this embodiment is realized by the prior art.

[0030] Figure 2 It shows the speed control method of the electromagnetic eddy current assembly of the present invention. The main functions of the electromagnetic eddy current assembly speed control are: when the tidal current velocity measured at the front end of the tidal current impeller is lower than the rated tidal current velocity value, the gap width between the permanent magnet disc and the copper disc in the electromagnetic eddy current assembly is adjusted and controlled to control the magnetic transmission torque and the speed, so as to optimize the operation condition of the unit and make it operate at the optimal power point; when the measured tidal current velocity is higher than its rated value, by adjusting the gap size of the electromagnetic eddy current assembly, the unit operates stably under the condition of constant speed or constant power. As Figure 2 shown, the main difference between the two control methods lies in the calculation method of the given optimal speed When the tidal current velocity measured at the front end of the tidal current impeller is lower than the rated tidal current velocity value, the optimal speed is determined by the product of the measured tidal current velocity value and the optimal tip speed ratio of the unit; when the measured tidal current velocity is higher than its rated value, the optimal speed value is determined by the generator output power and the currently measured speed.

[0031] The difference between the optimal speed value and the actually measured value is taken, and the difference is output as the optimal gap value via the proportional-integral controller This gap value is used as the reference input value and compared with the actually measured gap value Take the difference, and input the difference value into the clearance actuator. The clearance actuator has an internal self-closed-loop controller, which can generate corresponding control quantities according to this clearance difference value to change the rotational speed, torque, and power transmitted by the electromagnetic eddy current component, thereby realizing the overall operation optimization of the power flow generating unit. The system structure diagram is as shown in Figure 3 . Among them, the four system blocks are a proportional-integral calculator, a proportional-integral controller of the clearance actuator, an equivalent transfer function of the current inner loop, and a compensation link for the delay control of the digital control itself. T s is the system sampling period, and the reference values of the remaining parameters are as follows:

[0032] .

[0033] The content described in the embodiments of this specification is only a list of implementation forms of the inventive concept and is only for illustrative purposes. The protection scope of the present invention should not be regarded as limited to the specific forms stated in this embodiment. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those of ordinary skill in the art based on the inventive concept of the present invention.

Claims

1. An eddy current transmission continuously variable speed tidal current generator set, characterized in that: The tidal current generator set comprises a tidal current impeller, a main transmission shaft, a planetary gear train, an electromagnetic eddy current component and a permanent magnet generator. The tidal current impeller is used to convert the captured ocean kinetic energy into the mechanical kinetic energy of the planetary gear train. The tidal current impeller is fixedly connected to the main transmission shaft, the main transmission shaft is connected to the input side of the planetary gear train, the output side of the planetary gear train is connected to the copper disk rotor of the electromagnetic eddy current component, the permanent magnet disk rotor of the electromagnetic eddy current component is connected to the permanent magnet generator through a parallel shaft gear train, and the permanent magnet disk rotor and the copper disk rotor can rotate freely relative to each other; the planetary gear train, the electromagnetic eddy current component and the double-series parallel shaft speed-increasing gear train are used to convert the tidal current kinetic energy captured by the tidal current impeller into a relatively stable electric power output; by effectively controlling the internal clearance value of the electromagnetic eddy current component, the tidal current impeller can always track the optimal power point under the condition of time-varying tidal current flow velocity, that is, the tidal current generator set can be kept in a state of high efficiency and optimal power point, and the maximum tidal current kinetic energy is captured and the optimal power output is achieved; The speed control method of the electromagnetic eddy current component is as follows: when the tidal flow velocity measured at the front end of the tidal impeller is lower than the rated tidal flow velocity value, the magnetic transfer torque and the speed are controlled by adjusting and controlling the gap width between the permanent magnetic disk and the copper disk in the electromagnetic eddy current component, thereby optimizing the operation condition of the unit and making it operate at the optimal power point; when the tidal flow velocity measured at the front end of the tidal impeller is higher than its rated value, the gap size of the electromagnetic eddy current component is adjusted so that the unit can operate stably at a constant speed or constant power; when the tidal flow velocity measured at the front end of the tidal impeller is lower than the rated tidal flow velocity value, the optimal speed is determined by the product of the measured tidal flow velocity value and the optimal blade tip speed ratio of the unit; when the tidal flow velocity measured is higher than its rated value, the optimal speed value is determined by the generator output power and the speed currently measured; The optimal speed value is subtracted from the actual value obtained by measurement, and the difference is output as the optimal gap value δ through the proportional integral controller. * , the gap value is used as the reference input value, and the difference is made with the gap value δ actually measured, and the difference is input into the gap actuator. The gap actuator has a self-closed loop controller inside, which can generate corresponding control quantity according to the gap difference to change the speed, torque and power transmitted by the electromagnetic eddy current component, thereby realizing the overall operation optimization of the tidal generator set.

2. The eddy current transmission continuously variable speed tidal current generator set according to claim 1, characterized in that: The planetary gear train includes a planet carrier, a ring gear, planetary wheels and a sun wheel. The ring gear is fixed in a housing. The input side of the planetary gear train is the planet carrier. The planetary wheels are mounted on the planet carrier. The planetary wheels are meshed with the sun wheel and the inner ring of the ring gear at the same time. The output side of the planetary gear train is the sun wheel. The sun wheel is used to transfer the mechanical kinetic energy of the impeller to the electromagnetic eddy current assembly.

3. The eddy current transmission continuously variable speed tidal current generator set according to claim 1 or 2, characterized in that: The parallel shaft gear train includes a front parallel shaft pinion, a front parallel shaft gear, a rear parallel shaft pinion and a rear parallel shaft gear. The permanent magnetic disk rotor of the electromagnetic eddy current assembly is connected to the rotating shaft of the front parallel shaft pinion, the front parallel shaft pinion is meshed with the front parallel shaft gear, the front parallel shaft gear is coaxially installed with the rear parallel shaft pinion, the rear parallel shaft pinion is meshed with the rear parallel shaft gear, and the rotating shaft of the rear parallel shaft gear is connected to the motor shaft of the permanent magnet generator.

4. The eddy current transmission continuously variable speed tidal current generator set according to claim 1 or 2, characterized in that: In the electromagnetic eddy current component, the permanent magnetic disk rotor is composed of permanent magnets alternately arranged in the circumferential direction. When working, there is a relative speed difference, i.e., slip, between the permanent magnetic disk rotor and the copper disk rotor. The copper disk generates eddy currents in the alternating magnetic field, and the magnetic field induced by the eddy currents couples with the original magnetic field, thereby generating a magnetic transfer torque, which in turn drives the permanent magnetic disk rotor to rotate in the same direction as the copper disk.

Images