Counter-rotating ocean current power generating unit coupled with planetary gear train and generator

Abstract

A counter-rotating ocean current generator set, coupling a planetary gear train and a generator, includes an impeller, a magnetic coupling, a planetary gear train, a coreless axial flux permanent magnet synchronous motor, and a waterproof housing. The magnetic coupling, planetary gear train, and coreless axial flux permanent magnet synchronous motor are all installed within the waterproof housing. The impeller is mounted on the front end of the waterproof housing via an impeller shaft. The planetary gear train includes a planet carrier, an internal gear ring, planet gears, and a sun gear. The planet carrier is fixedly installed, the sun gear is connected to the generator housing, and the internal gear ring is connected to the generator shaft. The generator shaft and impeller shaft are connected via the magnetic coupling. This invention enables the generator housing and generator shaft to rotate in opposite directions, transforming one stator of the motor into a counter-rotating rotor, thus forming a dual-rotor motor configuration, increasing the relative speed of the generator, and thereby improving efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new energy utilization, and relates to a counter-rotating ocean current energy generator set coupled with a planetary gear train and a generator. BACKGROUND

[0002] China has vast sea areas, but the ocean current energy resources are unevenly distributed, and the flow speed of the ocean current in most sea areas is slow. The existing large generator sets are not suitable for these sea areas, and it is necessary to develop ocean current energy generator sets for low flow speed sea conditions. Compared with wind turbines, the ocean current energy has high energy density, but the flow speed is slow. In order to achieve the best energy capture effect, the rotational speed of the ocean current energy generator set is also slower, which is not conducive to the generator working in the optimal speed range and will reduce the electromechanical conversion efficiency. The influence is even greater under low flow speed sea conditions. The traditional ocean current energy generator set usually adopts a gear box form to realize speed increasing transmission, and in order to achieve a large transmission ratio, a multi-stage gear box structure is needed, and the cumulative transmission loss of each stage is not negligible. Matching the impeller rotational speed with the optimal generator speed range is a problem that needs to be solved for low flow speed ocean current energy generator sets.

[0003] Due to the relatively low energy density of low flow speed ocean current, the torque captured by the impeller from the ocean current is greatly reduced, which not only directly affects the capture power of the generator set, but also greatly affects the starting characteristics of the low flow speed ocean current energy generator set. The starting process of the ocean current energy generator set is essentially the process of the impeller rotating against the friction torque, electromagnetic torque and other torques. The rotational speed of the generator set during starting is not enough to support the operation of the motor to generate electricity, at this time the electromagnetic torque can be ignored, and it is necessary to reduce the friction loss of each transmission link as much as possible, and to reduce or even eliminate the torque part such as motor tooth slot torque, which will greatly improve the starting process of the low flow speed generator set.

[0004] In summary, low power generation efficiency and high starting flow speed are problems that need to be solved for low flow speed ocean current energy generator sets. Developing an ocean current energy generator set suitable for low flow speed to realize high efficiency power generation of the generator set in multiple sea conditions has practical significance for "sea energy for sea use". SUMMARY

[0005] To solve the above problems existing in the prior art, the application provides a counter-rotating ocean current energy generator set coupled with a planetary gear train and a generator, which increases the relative rotational speed of the generator and improves the efficiency.

[0006] The technical scheme adopted by the application is as follows:

[0007] The application discloses a contra-rotating ocean current power generator set coupled with a planetary gear train and a generator, which comprises a impeller, a magnetic coupling, a planetary gear train, a coreless axial flux permanent magnet synchronous motor and a waterproof shell, wherein the magnetic coupling, the planetary gear train and the coreless axial flux permanent magnet synchronous motor are all installed in the waterproof shell, the impeller is installed outside the front end of the waterproof shell through an impeller shaft, the planetary gear train comprises a planet carrier, an inner ring gear, planet gears and a sun gear, the planet carrier is fixedly arranged, the sun gear is connected with a generator shell, the inner ring gear is connected with a generator rotating shaft, and the generator rotating shaft is connected with the impeller shaft through the magnetic coupling. The planet carrier of the planetary gear train is fixed, the sun gear is connected with the generator shell, the inner ring gear is connected with the generator rotating shaft, and the generator rotating shaft is connected with the impeller shaft through the magnetic coupling, so that the generator shell and the generator rotating shaft can rotate reversely, one stator of the motor is changed into a reversely rotating rotor, a double-rotor motor form is formed, the relative rotating speed of the generator is increased, and the efficiency is improved. The generator of the application adopts the coreless axial flux permanent magnet synchronous motor, so that the cogging torque is eliminated, and the adverse effect on the starting of the generator set is avoided.

[0008] Further, the waterproof shell comprises an end cover, a bearing seat, a magnetic transmission shell, a motor shaft shell, a planetary gear train shell and a generator shell which are sequentially and fixedly connected, and O-shaped sealing rings are arranged at the joint surfaces of the end cover, the bearing seat, the magnetic transmission shell, the motor shaft shell, the planetary gear train shell and the generator shell.

[0009] Further, the magnetic coupling comprises a magnetic coupling inner rotor, a separation cover and a magnetic coupling outer rotor, N-pole and S-pole permanent magnets are annularly and crossly arranged on the magnetic coupling inner rotor and the magnetic coupling outer rotor, the magnetic coupling inner rotor is connected with the impeller shaft, and the magnetic coupling outer rotor is connected with the generator rotating shaft. The application utilizes the magnetic field to transmit torque, so that non-contact transmission is realized, and the friction loss caused by dynamic sealing is avoided.

[0010] Further, the planetary gear train adopts a 2K-H type planetary gear train. The planetary gear train is of an NGW type according to the meshing mode, the planet carrier is fixed, according to the transmission characteristics of the gear train, when the gear train is stably operated, the rotating speed ratio of the sun gear and the inner ring gear will be a constant value less than -1, that is, the sun gear realizes reverse speed increasing effect compared with the inner ring gear, and the constant value is related to the tooth number of the sun gear and the inner ring gear.

[0011] Further, the impeller shaft is installed in the bearing seat through two ceramic bearings, one end of the impeller shaft penetrates through the end cover and is connected with the impeller, and the other end of the impeller shaft penetrates into the magnetic transmission shell and is connected with the magnetic coupling inner rotor.

[0012] Further, the magnetic coupling outer rotor is installed in the magnetic transmission shell through two metal bearings, a baffle ring is arranged between the front metal bearing and the isolation cover, and a transition sleeve is arranged between the rear metal bearing and the magnetic coupling outer rotor.

[0013] Further, the generator rotating shaft passes through the motor shaft shell, the planetary gear train shell and enters the generator shell to be connected with the coreless axial flux permanent magnet synchronous motor, the rear end of the coreless axial flux permanent magnet synchronous motor is provided with a tail end shaft, and metal bearings are arranged between the generator rotating shaft and the planetary gear train shell and between the tail end shaft and the generator shell.

[0014] Further, the planet carrier is fixed on the planetary gear train shell, and the planetary gears are installed on the planet carrier and are in meshing connection with the sun gear and the inner ring gear respectively.

[0015] Further, the impeller shaft and the impeller, the magnetic coupling outer rotor and the generator rotating shaft, and the generator rotating shaft and the inner ring gear are connected through flat keys.

[0016] The application has the beneficial effect that the planet carrier of the planetary gear train is fixed, the sun gear is connected with the generator shell, the inner ring gear is connected with the generator rotating shaft, and the generator rotating shaft is connected with the impeller shaft through the magnetic coupling, so that the generator shell and the generator rotating shaft can rotate reversely, one stator of the motor is changed into a reversely rotating rotor, a double rotor motor form is formed, the relative rotating speed of the generator is increased, and the efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 It is a structural schematic diagram of the application.

[0018] Fig. 2 It is a three-dimensional structural schematic diagram of the application.

[0019] Fig. 3 It is a simplified schematic diagram of the planetary gear train of the application.

[0020] In the figure, 1 is an impeller, 2 is a first flat key, 3 is an impeller shaft, 4 is an end cover, 5 is a first ceramic bearing, 6 is a bearing seat, 7 is a second ceramic bearing, 8 is a magnetic transmission shell, 9 is a baffle ring, 10 is a first metal bearing, 11 is a second flat key, 12 is a transition sleeve, 13 is a second metal bearing, 14 is a magnetic coupling inner rotor, 15 is an isolation cover, 16 is a magnetic coupling outer rotor, 17 is a motor shaft shell, 18 is a generator rotating shaft, 19 is a third metal bearing, 20 is a shaft sleeve, 21 is a planetary gear train shell, 22 is a third flat key, 23 is an inner ring gear, 24 is a micro bearing, 25 is a planetary gear, 26 is a planet carrier, 27 is a sun gear, 28 is a coreless axial flux permanent magnet synchronous motor, 29 is a generator shell, 30 is a tail end shaft, and 31 is a fourth metal bearing. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] See Figs. 1-3This embodiment provides a counter-rotating ocean current generator set with a planetary gear train and a generator coupled together. It includes an impeller 1, a magnetic coupling, a planetary gear train, a coreless axial flux permanent magnet synchronous motor 28, and a waterproof housing. The magnetic coupling, planetary gear train, and coreless axial flux permanent magnet synchronous motor 28 are all installed inside the waterproof housing. The impeller 1 is mounted on the front end of the waterproof housing via an impeller shaft 3. The planetary gear train includes a planet carrier 26, an internal gear ring 23, planet gears 25, and a sun gear 27. The planet carrier 26 is fixedly installed, the sun gear 27 is connected to the generator housing, the internal gear ring 23 is connected to the generator shaft 18, and the generator shaft 18 is connected to the impeller shaft 3 via a magnetic coupling. In this invention, the planetary carrier 26 of the planetary gear train is fixed, the sun gear 27 is connected to the generator housing, and the internal gear ring 23 is connected to the generator shaft 18. Simultaneously, the generator shaft 18 is connected to the impeller shaft 3 via a magnetic coupling. This allows the generator housing and generator shaft 18 to rotate in opposite directions, transforming one stator of the motor into a counter-rotating rotor, thus forming a dual-rotor motor. This increases the relative speed of the generator, thereby improving efficiency. The generator of this invention uses a coreless axial flux permanent magnet synchronous motor 28, eliminating cogging torque and avoiding adverse effects on unit startup.

[0026] This embodiment provides a sealed environment for the transmission system and generator set, with the entire nacelle employing a static sealing method. Specifically, the waterproof housing includes an end cover 4, a bearing seat 6, a magnetic drive housing 8, a motor shaft housing 17, a planetary gear housing 21, and a generator housing 29, which are sequentially fixedly connected. O-rings are provided at the mating surfaces of the end cover 4, bearing seat 6, magnetic drive housing 8, motor shaft housing 17, planetary gear housing 21, and generator housing 29. The impeller 1 uses blades designed for low-velocity ocean currents. The impeller 1 rotates under the impact of the ocean current, obtaining speed and torque, thereby achieving power capture.

[0027] The magnetic coupling described in this embodiment includes an inner rotor 14, an isolation cover 15, and an outer rotor 16. Both the inner and outer rotors have N-pole and S-pole permanent magnets evenly distributed in a ring-shaped cross pattern. The inner rotor 14 is connected to the impeller shaft 3. The impeller shaft 3 is installed in a bearing housing 6 via a first ceramic bearing 5 and a second ceramic bearing 7. One end of the impeller shaft 3 protrudes through an end cover 4 and is connected to the impeller 1 via a first flat key 2. The other end of the impeller shaft 3 enters the magnetic transmission housing 8 and is connected to the inner rotor 14. The magnetic coupling transmits the rotational speed and torque of the impeller shaft 3 to the generator shaft 18 inside the housing. The outer rotor 16 of the magnetic coupling is connected to the generator shaft 18 via a second flat key 11. The outer rotor 16 is mounted in the magnetic transmission housing 8 via a first metal bearing 10 and a second metal bearing 13. A retaining ring 9 is provided between the first metal bearing 10 and the isolation cover 15, and a transition sleeve 12 is provided between the second metal bearing 13 and the outer rotor 16. This invention utilizes a magnetic field to transmit torque, thereby achieving non-contact transmission and avoiding frictional losses caused by dynamic seals.

[0028] The planetary gear train described in this embodiment is a 2K-H type planetary gear train. The planetary gear train is an NGW type gear train with a fixed planet carrier. According to the transmission characteristics of this gear train, when the gear train is running stably, the speed ratio between the sun gear and the internal ring gear will be a constant value less than -1. That is, the sun gear achieves a reverse speed increase effect relative to the internal ring gear, and the magnitude of this constant value is related to the number of teeth on the sun gear and the internal ring gear. The planet carrier 26 is fixed on the planetary gear train housing 21, and the planet gears 25 are mounted on the planet carrier 26 via miniature bearings 24 and are meshed with the sun gear 27 and the internal ring gear 23, respectively. The generator shaft 18 is connected to the internal ring gear 23 via a third flat key 22. The generator shaft 18 passes through the motor shaft housing 17 and the planetary gear housing 21 and enters the generator housing 29 to connect with the coreless axial flux permanent magnet synchronous motor 28. The rear end of the coreless axial flux permanent magnet synchronous motor 28 is provided with a tail shaft 30. A bushing 20 and a third metal bearing 19 are provided between the generator shaft 18 and the planetary gear housing 21. A fourth metal bearing 31 is provided between the tail shaft 30 and the generator housing 29.

[0029] Since the permanent magnet inside the coreless axial flux permanent magnet synchronous motor 28 is fixed on the generator housing and the winding rotates with the generator shaft, the generator permanent magnet and winding can rotate relative to each other through the coupling connection between the planetary gear train and the generator components, thereby increasing the relative speed of the generator. Furthermore, since the speed of the sun gear is higher than the speed of the internal gear ring (equal to the impeller speed when the unit is running stably), the relative speed of the generator can reach several times the impeller speed.

[0030] Given that the internal gear ring has z1 teeth, the planet gears have z2 teeth, and the sun gear has z3 teeth, then according to the transmission characteristics of planetary gear trains, the ratio of the speeds of the sun gear to the internal gear ring is:

[0031]

[0032] Furthermore, the rotational speed of the internal gear ring is equal to the rotational speed of the motor shaft, and when the unit is running stably, it is equal to the rotational speed of the impeller, i.e., n1 = n blade The relative speed of the generator is

[0033]

[0034] This invention uses a planetary gear train with a fixed planetary carrier, a sun gear connected to the generator housing, and an internal gear ring connected to the generator shaft. Simultaneously, the generator shaft and impeller shaft are connected via a magnetic coupling. This allows the generator housing and generator shaft to rotate in opposite directions, turning one stator of the motor into a rotor rotating in the opposite direction, thus forming a dual-rotor motor. This increases the relative speed of the generator and improves efficiency.

Claims

1. A counter-rotating ocean current generator set with a planetary gear train and a generator coupled together, comprising an impeller, a magnetic coupling, a planetary gear train, a coreless axial flux permanent magnet synchronous motor, and a waterproof housing, wherein the magnetic coupling, the planetary gear train, and the coreless axial flux permanent magnet synchronous motor are all installed inside the waterproof housing, and the impeller is mounted on the front end of the waterproof housing via an impeller shaft, characterized in that: The planetary gear train includes a planet carrier, an internal gear ring, planet gears, and a sun gear. The planet carrier is fixedly installed, the sun gear is connected to the generator housing, the internal gear ring is connected to the generator shaft, and the generator shaft is connected to the impeller shaft via a magnetic coupling. The planetary gear train adopts a 2K-H type planetary gear train. The planet carrier is fixed on the planetary gear train housing, and the planet gears are installed on the planet carrier and respectively mesh with the sun gear and the internal gear ring.

2. The counter-rotating ocean current generator set according to claim 1, characterized in that: The waterproof housing includes an end cover, a bearing seat, a magnetic drive housing, a motor shaft housing, a planetary gear system housing, and a generator housing, which are fixedly connected in sequence. O-rings are provided at the joint surfaces of the end cover, bearing seat, magnetic drive housing, motor shaft housing, planetary gear system housing, and generator housing.

3. A counter-rotating ocean current generator set with planetary gear train and generator coupled together according to claim 2, characterized in that: The magnetic coupling includes an inner rotor, an isolation cover, and an outer rotor. Both the inner and outer rotors are equipped with N-pole and S-pole permanent magnets arranged in a ring-shaped cross pattern. The inner rotor is connected to the impeller shaft, and the outer rotor is connected to the generator shaft.

4. A counter-rotating ocean current generator set with planetary gear train and generator coupled together according to claim 2, characterized in that: The impeller shaft is installed in the bearing housing through two ceramic bearings. One end of the shaft extends out of the end cover and is connected to the impeller, while the other end enters the magnetic transmission housing and is connected to the rotor inside the magnetic coupling.

5. A counter-rotating ocean current generator set with planetary gear train and generator coupled together according to claim 3, characterized in that: The outer rotor of the magnetic coupling is mounted in the magnetic transmission housing through two metal bearings. A retaining ring is provided between the front metal bearing and the isolation cover, and a transition sleeve is provided between the rear metal bearing and the outer rotor of the magnetic coupling.

6. A counter-rotating ocean current generator set with planetary gear train and generator coupled together according to claim 2, characterized in that: The generator shaft passes through the motor shaft housing and the planetary gear system housing and enters the generator housing to connect with the coreless axial flux permanent magnet synchronous motor. The rear end of the coreless axial flux permanent magnet synchronous motor is provided with a tail shaft. Metal bearings are provided between the generator shaft and the planetary gear system housing, and between the tail shaft and the generator housing.

7. A counter-rotating ocean current generator set with planetary gear train and generator coupled together according to claim 3, characterized in that: The impeller shaft and the impeller, the outer rotor of the magnetic coupling and the generator shaft, and the generator shaft and the internal gear ring are all connected by flat keys.

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