Eddy current transmission stepless speed change type tidal current generator set

Abstract

An eddy current transmission stepless speed change type tidal current generator set belongs to the field of tidal current / ocean current power generation, and comprises a tidal current impeller, a main transmission shaft, a planetary gear train, an electromagnetic eddy current assembly and a permanent magnet generator, the tidal current impeller is used for converting captured ocean current kinetic energy into mechanical kinetic energy of the planetary gear train, and the tidal current impeller is fixedly connected with the main transmission shaft; the main transmission shaft is connected with the input side of the planetary gear train, the output side of the planetary gear train is connected with a copper disc rotor of the electromagnetic eddy current assembly, a permanent magnet disc rotor of the electromagnetic eddy current assembly is in transmission connection with the permanent magnet generator through the parallel shaft gear train, and the permanent magnet disc rotor and the copper disc rotor can freely and relatively rotate. The device is simple, compact, stepless and continuous in speed change and high in efficiency.

Description

Technical Field

[0001] The invention belongs to the field of tidal / ocean current power generation, and relates to an eddy current transmission continuously variable speed tidal current generator set. Background Art

[0002] 70% of the earth's surface is covered by the ocean, which contains a huge source of energy. Therefore, the effective development and utilization of ocean energy resources is an important way to achieve sustainable development in the future and an important means to solve the potential energy crisis. Ocean tidal energy is the kinetic energy generated by the periodic ebb and flow of seawater due to the gravitational force of the moon. Unlike 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, the development and utilization of tidal energy has high economic value and market prospects.

[0003] Tidal current energy generators are important equipment for developing and utilizing tidal energy and realizing the conversion of tidal kinetic energy into electrical energy. In the past decade, various types of tidal current energy generators have been launched one after another, and have gradually been commercialized and mass-produced and applied. Existing tidal current energy generators mainly adopt a horizontal axis arrangement to capture and absorb the tidal kinetic energy of axial flow. Existing horizontal axis tidal current energy generators adopt a certain transmission form to achieve the transmission of mechanical kinetic energy and electrical power output. The main transmission forms are direct drive transmission with unit transmission ratio and gearbox speed increase transmission. When direct drive transmission is adopted, the generator is directly connected to the tidal current energy blades, and the vibration and load fluctuation of the blades can also be directly transmitted to the generator end. The generators of tidal current energy generators using direct drive transmission are usually large in size, and have high requirements for reliability and excitation strength, which leads to a significant increase in the overall cost of the unit.

[0004] When the gearbox is used for transmission, the speed of the low-speed shaft connected to the blades can be increased by the gearbox and then 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 addressed. Moreover, the speed increase ratio of the gearbox is fixed and cannot be changed. Therefore, it is difficult to change the overall speed of the unit in real time with the tidal flow rate.

[0005] Another common transmission form is the tidal energy generator set with low-speed hydraulic direct drive. Low-speed hydraulic transmission has the advantage of flexible transmission and can achieve stepless and continuous control of the transmission ratio. However, the main problem of low-speed hydraulic transmission is that the transmission efficiency is low, only about 70%, and the high-pressure and high-flow hydraulic components of the tidal energy generator set need to be designed and processed separately, which also increases the cost and expenditure to a certain extent.

[0006] In summary, the transmission modes of various existing tidal energy generators currently have a series of problems such as low efficiency, fixed transmission ratio, large size and high cost. Therefore, there is an urgent need for a transmission mode with compact structure, continuous stepless speed regulation and high efficiency. Summary of the invention

[0007] In order to overcome the shortcomings of existing tidal energy power generation methods such as low efficiency, fixed transmission ratio, large size and high cost, the present invention provides an eddy current transmission continuously variable tidal power generation unit with simple and compact structure, stepless continuous speed change and high efficiency.

[0008] The technical solution adopted by the present invention to solve its technical problem is: A vortex drive continuously variable speed tidal current generator set comprises a tidal current impeller, a main transmission shaft, a planetary gear train, an electromagnetic eddy current assembly and a permanent magnet generator, wherein 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 assembly, the permanent disk rotor of the electromagnetic eddy current assembly is transmission-connected to the permanent magnet generator via a parallel shaft gear train, and the permanent disk rotor and the copper disk rotor can rotate freely relative to each other.

[0009] Furthermore, the planetary gear system includes a planet carrier, a ring gear, a planetary gear and a sun gear, the ring gear is fixed in the housing, the input side of the planetary gear system is the planet carrier, the planetary gear is mounted on the planet carrier, the planetary gear is meshed with the sun gear and the inner ring of the ring gear at the same time, and the output side of the planetary gear system is the sun gear, which is used to transfer the mechanical kinetic energy of the impeller to the electromagnetic eddy current assembly. Of course, other planetary gear transmission methods can also be used.

[0010] Furthermore, the parallel axis gear system includes a front parallel axis pinion, a front parallel axis gear, a rear parallel axis pinion and a rear parallel axis gear, the permanent magnetic disc rotor of the electromagnetic eddy current assembly is connected to the rotating shaft of the front parallel axis pinion, the front parallel axis pinion is meshed with the front parallel axis gear, the front parallel axis gear is coaxially installed with the rear parallel axis pinion, the rear parallel axis pinion is meshed with the rear parallel axis gear, and the rotating shaft of the rear parallel axis gear is connected to the motor shaft of the permanent magnet generator. Of course, other parallel axis gear transmission methods can also be used.

[0011] Furthermore, in the electromagnetic eddy current component, the permanent magnetic disk rotor is composed of permanent magnets alternately arranged in the circumferential direction. During operation, 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.

[0012] The present invention adopts a planetary gear train, an electromagnetic eddy current component and a dual-series parallel shaft speed-increasing gear train to convert the tidal kinetic energy captured by the tidal impeller into a relatively stable electric power output. By effectively controlling the internal clearance value of the electromagnetic eddy current component, the tidal impeller can always track the optimal power point under the condition of time-varying tidal flow velocity, that is, the tidal generator set can be kept in a state of high efficiency and optimal power point, achieving the capture of maximum tidal kinetic energy and the output of optimal power. When the tidal flow velocity is higher than the rated one, the electromagnetic eddy current component can be effectively controlled so that the speed and power at the generator end are maintained at the rated value, so that the overall output power of the unit can be stabilized.

[0013] The beneficial effects of the present invention are mainly manifested in: 1. The tidal current generator set of the present invention can realize stepless speed control and optimal power point operation of the set by controlling the electromagnetic eddy current component, and has higher efficiency of energy conversion and output.

[0014] 2. The tidal energy generator set of the present invention has a relatively simple and compact structure, is easy to install, and has a relatively low overall operating cost. The transmission shaft allows a larger installation centering error and can achieve non-contact connection, which can effectively reduce and eliminate the transmission of vibration and load between the tidal impeller and the generator, and can significantly reduce the impact of instantaneous high tidal loads.

[0015] 3. The electromagnetic eddy current component used in 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.

[0016] 4. It has a relatively outstanding high-efficiency and energy-saving effect. It does not require a high-energy-consuming hydraulic source like a low-speed hydraulic transmission. It only requires limited electromagnetic energy input to achieve stepless speed operation of the entire unit. It can also achieve gradual and gentle flexible operation and precise speed regulation and power control for various types of generators and tidal impeller loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of a rotation speed control method of an electromagnetic eddy current component of the present invention; Figure 3 It is the control principle diagram of proportional-integral controller and self-closed-loop controller.

[0018] The figure numbers are as follows: 1-tidal impeller, 2-main transmission shaft, 3-planet carrier, 4-ring gear, 5-planetary 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. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] Reference Figure 1~Figure 3 A eddy current drive continuously variable speed tidal current generator set comprises a tidal current impeller 1, a main transmission shaft 2, a planetary gear train, an electromagnetic eddy current component 7, and a permanent magnet generator 12. The tidal impeller 1 is used to convert the captured ocean kinetic energy into the mechanical kinetic energy of the planetary gear system. The tidal impeller 1 is fixedly connected to the main transmission shaft 2. The planetary gear system includes a planetary carrier 3, a ring gear 4, a planetary wheel 5 and a sun wheel 6. The ring gear 4 is fixed in a casing. The main transmission shaft 2 is connected to the planetary carrier 5. The planetary wheel 5 is installed on the planetary carrier 5. The planetary wheel 5 is meshed with the sun wheel 6 and the inner ring of the ring gear 4 at the same time. The sun wheel 6 is used to transfer the mechanical kinetic energy of the impeller to the electromagnetic eddy current component 7.

[0021] The rotating shaft of the sun gear 6 is connected to the copper disk rotor of the electromagnetic eddy current assembly 7, and the permanent magnetic disk rotor of the electromagnetic eddy current assembly 7 is transmission-connected to the permanent magnet generator 12 through a parallel axis gear train, and the permanent magnetic disk rotor and the copper disk rotor can rotate freely relative to each other.

[0022] 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 magnetic 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 is coaxially installed with the rear parallel shaft pinion 10, the rear parallel shaft pinion 10 is meshed with the rear parallel shaft gear 11, and the rotating shaft of the rear parallel shaft gear 11 is connected to the motor shaft of the permanent magnet generator 12.

[0023] The electromagnetic eddy current assembly 7 of this embodiment is mainly composed of two rotor disks, one of which is a permanent magnetic disk rotor connected to the front parallel shaft pinion 8, and the permanent magnetic disk rotor is composed of permanent magnets arranged alternately in the circumferential direction; the other part is a copper disk rotor connected to the sun gear 6, and the copper disk rotor group runs at the same speed as the sun gear 6. The permanent magnetic disk rotor and the copper disk rotor can rotate freely relative to each other. When working, there is a relative speed difference between the two, that is, slip, and the copper disk generates eddy current in the alternating magnetic field; according to Lenz's law, the magnetic field induced by the eddy current is coupled with the original magnetic field, thereby generating a magnetic transfer torque, and then driving the permanent magnetic disk to rotate in the same direction with the copper disk. When the speed difference between the two is reduced to a certain stable value, the magnetic transfer torque generated between the two gradually stabilizes, and finally the two rotor disks work stably at a certain fixed speed difference, realizing the kinetic energy transfer 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 transmitted through the two-stage speed increase effect of the front and rear parallel shaft gear system, and finally input into the permanent magnet generator 12 to realize electric power output.

[0024] The eddy current mechanism of the electromagnetic eddy current component 7 of this embodiment is realized by using the existing technology.

[0025] Figure 2 The invention shows the speed control method of the electromagnetic eddy current component. The main functions of the speed control of the electromagnetic eddy current component are: when the tidal flow velocity measured at the front end of the tidal impeller is lower than the rated tidal flow velocity, 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 unit operation condition and making it operate at the optimal power point; when the measured tidal flow velocity is higher than its rated value, the gap size of the electromagnetic eddy current component is adjusted to make the unit operate stably at a constant speed or constant power. Figure 2 As shown, the main difference between the two control methods is the given optimal speed The calculation method is different. When the tidal flow velocity measured at the front end of the tidal impeller is lower than the rated tidal flow velocity, the optimal speed is determined by the product of the measured tidal flow velocity and the optimal tip speed ratio of the unit; when the measured tidal flow velocity is higher than its rated value, the optimal speed is determined by the generator output power and the currently measured speed.

[0026] The optimal speed value is subtracted from the actual value obtained by measurement, and the difference is output as the optimal gap value through the proportional integral controller. , use this gap value as a reference input value and compare it with the gap value obtained by actual measurement. The difference is input into the gap actuator, which 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. Figure 3 As shown, the four system blocks are proportional-integral calculator, gap actuator proportional-integral controller, equivalent transfer function of current inner loop and compensation link for delay control of digital control itself, T s is the system sampling period, and the reference values ​​of other parameters are as follows:

[0027] .

[0028] The contents described in the embodiments of this specification are merely enumerations of implementation forms of the inventive concept and are for illustrative purposes only. The protection scope of the present invention should not be considered to be limited to the specific forms described in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be thought of by ordinary technicians in this field based on the inventive concept.

Claims

1. An eddy current transmission continuously variable speed tidal current generator set, characterized in that: The tidal current generator set 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 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 transmission-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.

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.

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