A cycloid magnetic gear composite generator for low-speed fluid kinetic energy power generation

Abstract

This invention relates to a cycloidal magnetic gear composite generator for low-speed hydrodynamic power generation, belonging to the field of combined motor and magnetic transmission technology, and can be applied to hydrodynamic power generation. It includes a stator, a translational rotor and crankshaft support mechanism, and an outer rotor. This invention combines a cycloidal magnetic gear structure with a radial variable reluctance power generation structure. The translational rotor serves simultaneously as the inner rotor of the cycloidal magnetic gear structure and the rotor of the radial variable reluctance power generation structure. During power generation, it has dual-channel output. The main output channel drives an external high-speed generator through the translational rotor crankshaft support mechanism. The auxiliary output channel utilizes the minimum air gap point of the non-uniform internal air gap to continuously move along the stator circumferentially with the translational rotor, inducing an electromotive force in the stator windings. This generator has dual-channel output fault tolerance, a simple and reliable structure, and eliminates the need for a mechanical gearbox, significantly reducing maintenance costs. It is particularly suitable for low-speed hydrodynamic power generation, such as wind power and ocean current / tidal current power generation applications.

Description

Technical Field

[0001] This invention belongs to the field of composite technology of electric motor and magnetic transmission, and relates to a cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation, which can be applied to fluid kinetic energy power generation systems. Background Technology

[0002] Hydrodynamic power generation is one of the most commercially promising renewable energy technologies. Its common characteristics include: the impeller speed of the primary energy-driven hydrodynamic energy harvesting system is very low; the rated speed of wind turbines is typically 10–25 rpm, and the impeller speed of tidal / ocean current power turbines is even lower, typically 5–15 rpm, while the required input speed of the generator is generally 1500–1800 rpm. Therefore, a gearbox is needed between the impeller and the generator for speed-increasing transmission. However, during operation, the speed-increasing mechanical gearbox is affected by irregular changes in hydrodynamic loads, making the gears prone to pitting or tooth breakage, leading to transmission failure. Especially in tidal / ocean current power generation applications, the maintenance cost of underwater gearboxes is extremely high, and the requirements for sealing reliability are stringent.

[0003] In recent years, permanent magnet gears have attracted widespread attention due to their advantages such as contactless transmission, overload protection, low noise, and low vibration. Among them, cycloidal permanent magnet gears, with their high torque density and large transmission ratio, have shown the potential to replace mechanical gears. However, existing cycloidal magnetic gear structures still face the following technical bottlenecks when applied to hydrodynamic power generation.

[0004] (1) Insufficient speed ratio; existing coaxial magnetic gears are based on the principle of magnetic field modulation, and their speed ratio is usually only 10-15, which is far lower than the speed ratio of 100-120 required by the fluid kinetic energy power generation system. (2) Complex motion conversion; the internal permanent magnet rotor of the cycloidal magnetic gear performs compound motion, simultaneously revolving around the main shaft and rotating around its own axis, requiring additional mechanical conversion mechanisms such as pins and pin disks to output torque, resulting in a complex structure and uneven force distribution. (3) Difficulty in integrating magnetic gears with motors; in magnetic gear compound motors, high-speed rotors and low-speed rotors need to be mechanically separated so that electromagnetic torque can be generated on the high-speed side through windings and amplified by the gear ratio. The rotor of the traditional cycloidal magnetic gear is not a mechanically separated high-speed and low-speed rotor, but a single rotor that simultaneously contains two motion components, making it difficult to directly integrate with the motor windings. (4) Radial unbalanced force; the eccentric structure of the cycloidal magnetic gear results in a significant radial unbalanced force during single-stage operation, which exacerbates bearing wear and vibration.

[0005] Therefore, given the severe wear of mechanical gears and high maintenance costs in existing low-speed hydroelectric power generation systems, as well as the large radial vibrations caused by eccentric motion, how to achieve low-vibration, high-transmission-ratio, and efficient low-speed kinetic energy conversion has become an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to address the technical problems of severe wear of mechanical gears and high operation and maintenance costs in existing low-speed fluid power generation systems, and to propose a cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation.

[0007] The objective of this invention is achieved through the following technical solution: A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation, characterized in that: it includes a stator, a translational rotor, and an outer rotor; the stator includes a stator core and a multi-phase concentrated winding wound on the stator core, the central axis of the stator core being the main shaft O1; the translational rotor is a ring-shaped structure, including a magnetically conductive yoke and a first permanent magnet; the magnetically conductive yoke is ring-shaped, the first permanent magnet is attached to the outer wall of the magnetically conductive yoke along the circumferential direction, the central axis of the translational rotor is the translational rotor axis O2, the translational rotor axis O2 is parallel to the main shaft O1, and the translational rotor is eccentrically fitted on the outside of the stator with an eccentricity e; there is a non-uniform inner air gap between the translational rotor and the stator; the translational rotor performs circumferential translational motion around the main shaft O1 without rotating around the translational rotor axis O2, and the non-uniform inner air gap is... The small air gap point moves continuously along the circumference of the stator as the translational rotor moves. The trajectory of the smallest air gap point is a circle with the main shaft O1 as the center and the eccentricity e as the radius. The translational rotor and the stator form a radial variable reluctance power generation structure. The motion of the translational rotor induces an electromotive force on the multiphase concentrated winding. The outer rotor is used to connect with the fluid kinetic energy harvesting impeller. The outer rotor is sleeved on the outside of the translational rotor and shares the main shaft O1 with the stator. A second permanent magnet is attached to the inner wall of the outer rotor along the circumference. There is a non-uniform external air gap between the outer rotor and the translational rotor. The outer rotor and the translational rotor form a cycloidal magnetic gear structure. The rotation of the outer rotor is converted into the motion of the translational rotor through magnetic field coupling and the cycloidal magnetic gear effect. The translational rotor can transmit torque to an external generator.

[0008] Furthermore, it also includes a crankshaft support mechanism that restricts the motion of the translational element; the crankshaft support mechanism includes at least three crankshafts, which are axially connected to the translational element; each crankshaft includes a main journal, crank arms, and crank pins connected in sequence, the main journals are evenly distributed around the main shaft O1, and the main journals are supported on a fixed end cover by bearings, the crank pins are evenly distributed around the translational element axis O2, and the crank pins are supported on the translational element by bearings, the length of the crank arms is equal to the eccentricity e, the crank arms are parallel to each other and have the same phase, constraining the translational element to perform circular translational motion around the main shaft O1 without rotating around the translational element axis O2, the circular translational motion of the translational element is converted into the rotation of the crankshaft by the crankshaft support mechanism, and at least one of the main journals transmits torque to an external generator.

[0009] Furthermore, the end face of the translational rotor has outwardly protruding boss bearing seats evenly distributed along the circumferential direction, and the crank pin is supported in the boss bearing seats by bearings.

[0010] Furthermore, the number of pole pairs of the first permanent magnet is pt, the number of pole pairs of the second permanent magnet is pr, and pr > pt, and the two satisfy pr - pt = 1; the gear transmission ratio i = pr / (pr - pt) = pr, and the gear transmission ratio ranges from 60 to 150.

[0011] Furthermore, the stator core is uniformly provided with 3 stator teeth along the circumferential direction, and the multiphase concentrated winding is a three-phase double-layer fractional slot concentrated winding with a winding pole pair number ps = 1 and a number of slots per pole per phase number q = 0.5.

[0012] Furthermore, a counterweight is fixedly provided on the translational element, and the counterweight is installed on the opposite eccentric side of the magnetic yoke, so that the center of mass of the translational element assembly coincides with the main shaft O1.

[0013] Furthermore, the low-speed fluid kinetic energy power generation cycloidal magnetic gear composite generator adopts an axial double-stage symmetrical layout, with the eccentricity directions of the two stages of the translational actuators differing by 180°, the two stages sharing the same outer rotor, and the two stages of the translational actuators having the same orbital frequency, the same speed, and opposite eccentricity directions.

[0014] Furthermore, an axial gap is provided between the two stages of the low-speed hydrodynamic power generation cycloidal magnetic gear composite generator, and the axial gap and / or the end of the low-speed hydrodynamic power generation cycloidal magnetic gear composite generator are provided with flexible damping supports to suppress residual torque.

[0015] Furthermore, the low-speed shaft of the fluid kinetic energy harvesting impeller is coaxially connected to the outer rotor, and the fluid kinetic energy harvesting impeller is a wind turbine for wind power generation or a water turbine for tidal power generation.

[0016] Furthermore, the fluid kinetic energy harvesting impeller drives the outer rotor to rotate at low speed, and the cycloidal magnetic gear structure couples the translational rotor to perform circumferential translational motion. On the one hand, the crankshaft output end of the translational rotor serves as a high-speed mechanical output port, and on the other hand, it causes the reluctance of the non-uniform inner air gap to change periodically, inducing an electromotive force in the multiphase concentrated winding. The crankshaft output end of the translational rotor is connected to the external generator, forming the main power output channel. The external generator is a permanent magnet synchronous generator. The radial variable reluctance generator structure operates in switched reluctance generator mode through an asymmetric half-bridge power converter, forming an auxiliary power output channel. The main power output channel and the auxiliary power output channel share a DC bus, and after merging, they are connected to the power grid through an inverter.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention integrates a cycloidal magnetic gear structure and a radial variable reluctance power generation structure into a single generator. The translational rotor serves as both the inner rotor of the cycloidal magnetic gear structure and the rotor of the radial variable reluctance power generation structure. The structure is simple and reliable, with the translational rotor performing pure translational motion and the outer rotor performing simple rotation. It eliminates the need for complex mechanical conversion mechanisms such as pins and pin disks, completely replacing the speed-increasing mechanical gearbox with the highest failure rate. This fundamentally eliminates the hidden dangers of gear pitting, tooth breakage, and lubrication failure. At the same time, it eliminates the need for a gearbox lubrication oil circulation system, thus avoiding gearbox seal leakage and regular oil change maintenance issues, significantly reducing operation and maintenance costs. It is particularly suitable for low-speed fluid kinetic energy power generation, such as wind power generation and ocean current / tidal current power generation applications where maintenance is difficult.

[0018] This invention systematically counteracts the radial force generated by the circumferential translational motion of a cycloidal gear by constructing a three-level radial force management scheme. Counterweight compensation eliminates mechanical imbalance forces; the axial double-stage symmetrical layout ensures that the two levels of radial forces cancel each other out under synchronized motion conditions; residual couple control ensures smooth operation under all working conditions. This invention fundamentally solves the common industry problem of radial imbalance forces in cycloidal magnetic gears.

[0019] This invention features the magnetic field modulation characteristics of a cycloidal magnetic gear, resulting in low output torque ripple and smooth operation. Through a single-range design (pr-pt = 1), a high speed ratio of 60–150 can be achieved with a single stage, meeting the speed requirements of low-speed hydrodynamic power generation systems. It employs a dual-channel power generation and fault tolerance system. The main power output channel drives an external generator at high speed via a translational rotor and crankshaft to output main electrical power, while the auxiliary power output channel utilizes a multi-phase concentrated winding to generate auxiliary electrical power through variable reluctance induction. The two channels serve as backups for each other, ensuring high system reliability. The permanent magnet synchronous generator in the main channel can generate electricity and establish DC bus voltage without excitation, providing excitation power for the auxiliary channel, enabling self-sustaining operation without external power. The multi-phase concentrated winding scheme provides redundancy and fault tolerance, allowing other phases to continue generating electricity even if one phase fails. This invention utilizes a compact structure of a high-speed-ratio cycloidal magnetic gear composite variable reluctance generator, enabling the entire unit to output higher electrical power within the same volume. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the radial structure of the single-stage cycloidal magnetic gear composite generator of the present invention; Figure 2 This is a schematic cross-sectional view of the overall axial structure of the two-stage cycloidal magnetic gear composite generator according to Embodiment 2 of the present invention; Wherein, 1—outer rotor; 2—second permanent magnet; 3—translator; 4—first permanent magnet; 5—stator; 6—non-uniform inner air gap; 7—non-uniform outer air gap; 8—eccentricity e; 9—main shaft O1; 10—translator axis O2; 11—multiphase concentrated winding; 12—counterweight; 13—fixed end cover; 14—crankshaft; 15—boss bearing seat. Detailed Implementation

[0021] To better illustrate the purpose and advantages of this invention, the invention will be further described below with reference to the accompanying drawings and examples. It should be noted that the implementation of this invention is not limited to the following embodiments, and any modifications or alterations made to this invention will fall within the scope of protection of this invention.

[0022] Example 1 To address the technical problems of existing low-speed fluid power generation systems, such as severe wear of mechanical gears, high operation and maintenance costs, insufficient speed ratio of cycloidal magnetic gears, complex motion conversion mechanisms, significant radial unbalanced force in magnetic gear composite motors, and insufficient reliability of single power generation channels, this embodiment proposes a cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation, including a stator 5, a translator 3, an outer rotor 1, and a crankshaft support mechanism.

[0023] The stator 5 includes a stator core and a multiphase concentrated winding 11 wound on the stator core. The multiphase concentrated winding 11 has no fewer than three phases and can adopt a five-phase, six-phase, or seven-phase winding structure. Preferably, the stator core has three stator teeth evenly arranged along the circumferential direction, and the multiphase concentrated winding 11 is a three-phase double-layer fractional slot concentrated winding with a pole pair number ps = 1 and a slot number per pole per phase q = 0.5.

[0024] The central axis of the stator core is the main shaft O19; the translator 3 is a ring-shaped structure, comprising a magnetic yoke and a first permanent magnet 4, made of neodymium iron boron (N48H); the magnetic yoke is ring-shaped, and the first permanent magnet 4 is attached to the outer wall of the magnetic yoke along the circumferential direction. The central axis of the translator 3 is the translator axis O210, which is parallel to the main shaft O19. The translator 3 is eccentrically fitted onto the outside of the stator 5 with an eccentricity e8; there is a non-uniform internal air gap 6 between the translator 3 and the stator 5; the translator 3, under the constraint of the crankshaft support mechanism, performs a circular translational motion around the main shaft O19 without rotating around the translator axis O210. When the translator 3 performs a circular translational motion, the trajectory of any point on it is a circle with a diameter of 2e.

[0025] The minimum air gap point of the non-uniform internal air gap 6 moves continuously along the circumference of the stator 5 as the translational rotor 3 moves. The trajectory of the minimum air gap point is a circle with the main shaft O19 as the center and the eccentricity e as the radius. The motion of the translational rotor 3 induces an electromotive force in the multiphase concentrated winding 11. The translational rotor 3 and the stator 5 constitute a radial variable reluctance generator structure. The radial variable reluctance generator structure is energized when the minimum air gap point approaches the multiphase concentrated winding 11 and turned off when it moves away. The multiphase concentrated winding 11 can feed back electrical energy to the DC bus. The multiphase concentrated winding 11 is connected to an asymmetrical half-bridge power converter and operates in switched reluctance generator mode, forming an auxiliary power output channel. Unlike conventional switched reluctance motors, the inductance change in this embodiment originates from the periodic change of the air gap length along the circumference, thereby modulating the magnetic flux of the multiphase concentrated winding 11, rather than relying on physical salient poles. The translational rotor 3 in this embodiment does not have the physical salient poles of a traditional variable reluctance generator rotor.

[0026] The crankshaft support mechanism includes at least three crankshafts 14, which are axially connected to the translation element 3. Preferably, the three crankshafts 14 are evenly and symmetrically distributed at 120° along the circumference. Each crankshaft 14 includes a main journal, a crank arm, and a crank pin connected in sequence. The main journals are evenly distributed around the main shaft O19 with a radius of Rc and are supported on the fixed end cover 13 by bearings. The crank pins are evenly distributed around the translation element axis O210 with a radius of Rc and are supported on the translation element 3 by bearings. Preferably, the end face of the translation element 3 has outwardly protruding boss bearing seats 15 evenly distributed along the circumference. The boss bearing seats 15 and the translation element 3 are integrally machined or fixedly connected together, and the crank pins are supported in the boss bearing seats 15 by bearings. The length of the crank arm is equal to the eccentricity e, that is, the eccentricity of the crank pin relative to the main journal is equal to the eccentricity e8 of the translator 3; the crank arms are parallel to each other and have the same phase, which constrains the motion mode of the translator 3, so that the translator 3 can only make circular translation motion around the main axis O19 and cannot rotate around the translator axis O210.

[0027] The circular translational motion of the translator 3 is converted into the high-speed rotation of the crankshaft 14 through the crankshaft support mechanism. The equivalent inertia of the translator 3 referred to the high-speed side is J. eq J eq = mt·e 2 mt is the mass of the translational boson, J eq Independent of the gear ratio and with a very small eccentricity e on the order of millimeters, it is beneficial for rapid dynamic response. The translational rotor 3 transmits torque to an external generator through a main journal, forming the main power output channel. The other two crankshafts 14 do not output power, but only participate in constraining the rotation of the translational rotor 3 and sharing the radial force.

[0028] The outer rotor 1 is used to connect with the fluid kinetic energy harvesting impeller; the low-speed shaft of the fluid kinetic energy harvesting impeller is coaxially driven with the outer rotor 1, and the fluid kinetic energy harvesting impeller is a wind turbine for wind power generation or a hydro turbine for tidal / ocean current power generation. The outer rotor 1 is sleeved on the outside of the translator 3 and shares a main shaft O19 with the stator 5. A second permanent magnet 2, made of neodymium iron boron (N48H), is attached to the inner wall of the outer rotor 1 along the circumferential direction. There is a non-uniform external air gap 7 between the outer rotor 1 and the translator 3. The outer rotor 1 and the translator 3 form a cycloidal magnetic gear structure. In this embodiment, the stator magnetic flux needs to be attenuated twice through the air gap. Under short-circuit conditions, the demagnetizing magnetic field reaching the surface of the permanent magnet is significantly weakened, and the permanent magnet has strong anti-demagnetizing ability. The rotation of the outer rotor 1 is converted into the translational motion of the translator 3 through magnetic field coupling and the cycloidal magnetic gear effect. Specifically, the second permanent magnet 2 on the inner wall of the outer rotor 1 rotates synchronously with the outer rotor 1. Through magnetic field coupling, the second permanent magnet 2 and the first permanent magnet 4 on the outer wall of the translator 3 are driven by a cycloidal magnetic gear, thereby driving the translational motion of the translator 3. The number of pole pairs of the first permanent magnet 4 is pt, and the number of pole pairs of the second permanent magnet 2 is pr, and pr > pt, satisfying pr - pt = 1; the gear ratio i = pr / (pr - pt) = pr, and the gear ratio ranges from 60 to 150. The orbital speed of the translator 3 is the product of the rotational speed of the outer rotor 1 and the gear ratio i. The orbital frequency of the translator is expressed as ftrans = (i•nin) / 60, where nin is the input rotational speed of the outer rotor (rpm); ftrans is the orbital frequency of the translator (Hz).

[0029] A counterweight 12 is fixedly mounted on the translator 3. The counterweight 12 is installed on the opposite eccentric side of the magnetic yoke, so that the center of mass of the translator 3 assembly coincides with the main shaft O1, thereby reducing eccentric vibration. The mass of the counterweight 12 matches the mass and eccentricity e of the translator 3. Since the eccentricity e is usually 1 to 2 mm, the volume of the counterweight 12 does not exceed 5% of the total volume of the translator 3.

[0030] The working principle of this embodiment is as follows: the fluid kinetic energy harvesting impeller drives the outer rotor 1 to rotate at low speed, and the cycloidal magnetic gear structure couples the translational rotor 3 to make a circular translational motion. On the one hand, the output end of the translational rotor 3 serves as a high-speed mechanical output port, and on the other hand, it causes the magnetic reluctance of the non-uniform inner air gap 6 to change periodically, inducing an electromotive force in the multiphase concentrated winding 11. The output end of the translational rotor 3 is connected to the external generator to form the main power output channel. The external generator is a permanent magnet synchronous generator. The radial variable reluctance generator structure operates in switched reluctance generator mode through an asymmetric half-bridge power converter to form an auxiliary power output channel. The main power output channel and the auxiliary power output channel share a DC bus, and after merging, they are connected to the power grid through an inverter.

[0031] The main output channel drives an external permanent magnet synchronous high-speed generator via crankshaft 14 to output the main electrical power, while the auxiliary output channel generates auxiliary electrical power using the variable reluctance effect. The two channels serve as backups for each other, ensuring high system reliability. The main channel permanent magnet generator can generate electricity to establish DC bus voltage without excitation, providing excitation power to the auxiliary output channel, enabling self-sustaining operation without an external power source.

[0032] The power generation principle and method of this embodiment include the following steps: Step 1: The fluid kinetic energy harvesting impeller captures the fluid kinetic energy, driving the outer rotor 1 to rotate synchronously around the main shaft O1 at a rated low speed, converting the fluid kinetic energy into the low-speed rotational torque of the outer rotor 1; Step 2: The second permanent magnet 2 on the inner wall of the outer rotor 1 rotates synchronously with the outer rotor 1. Through the magnetic field coupling effect in the eccentric non-uniform outer air gap 7, it forms a cycloidal magnetic gear transmission with the first permanent magnet 4 on the outer wall of the translator 3. The crankshaft support mechanism restricts the rotation of the translator 3. The translator 3 can only make circular translational motion around the main shaft O1, realizing the conversion from the low-speed rotation of the outer rotor 1 to the high-speed track translation of the translator 3. Step 3: The circular translation motion of the translation element 3 is converted into the rotation of the crankshaft 14 around the main journal through the crankshaft support mechanism. The crankshaft 14 transmits the high-speed torque to the high-speed external generator, and the external generator completes the electromechanical energy conversion. After rectification by the rectifier, electrical energy is output. This is the main power output channel. Step 4: The minimum air gap point of the non-uniform inner air gap 6 of the translator 3 moves continuously along the circumference of the stator 5 as the translator 3 moves, causing the inductance of each phase concentrated winding in the stator 5 to change continuously and periodically with the air gap magnetic reluctance; the winding conduction sequence is controlled by the asymmetrical half-bridge power converter, so that only the phase winding in the inductance decreasing region is turned on to participate in energy feedback at each moment, which is the auxiliary power output channel; multiple phases working at the same time can increase the power output per unit volume; Step 5: The main power output channel and the auxiliary power output channel share a DC bus. The electrical energy output from the main power output channel is rectified by the inverter and then fed into the DC bus. After being combined with the electrical energy output from the auxiliary power output channel, it is converted into AC power of power frequency that meets the grid standard by the grid-connected inverter and then fed into the grid.

[0033] This embodiment also features an electric operating mode. In electric operating mode, this embodiment can act as an active driver to rotate the impeller during black start, starting the power generation process without relying on an external power grid. Under low flow or low wind speed conditions, it actively assists the fluid kinetic energy harvesting impeller in starting and entering the working state, thereby transforming the generator from a passive component into an active and controllable intelligent actuator, comprehensively improving system reliability and operational performance. The specific principle and method are as follows: Pulse excitation current is sequentially applied to the multi-phase concentrated winding 11 of the stator 5 in phase sequence, generating a magnetic field that moves sequentially along the circumferential direction on the stator teeth. Due to the eccentric installation of the translational rotor 3 and the non-uniform state of the inner air gap, the electromagnetic force generated by the moving magnetic field drives the translational rotor 3 to perform synchronous circular orbital motion around the main shaft O19. The high-speed orbital motion of the translational rotor 3, through the magnetic field coupling effect of the outer air gap, drives the outer rotor 1 to rotate at low speed and high torque around the main shaft O19, thereby driving the fluid kinetic energy harvesting impeller to rotate.

[0034] Example 2 Based on Example 1, this embodiment of the low-speed hydrodynamic power generation cycloidal magnetic gear composite generator adopts an axial double-stage symmetrical layout. The eccentric directions of the two stages of the translational actuators 3 differ by 180°. The two stages share the same outer rotor 1, and the two stages of the translational actuators 3 have the same orbital frequency, the same speed, and opposite eccentric directions. The translational actuators 3 adopt a structure combining a double-stage symmetrical layout with counterweight compensation to counteract the radial unbalanced force of the non-uniform air gap magnetic field distribution with a cosine distribution, significantly reducing the net radial force on the main bearing of the outer rotor 1.

[0035] The radial force of the synchronous motion is expressed as: ; in, , These represent the radial forces generated by the first and second stages, respectively; when the two stages operate synchronously, | |=| |;so that the translational orbits of the two-stage translators 3 have the same frequency, the same linear velocity, and always opposite eccentricity.

[0036] Furthermore, the non-uniform air gap with a cosine distribution Represented as: ; in, This represents the average air gap length. It is the eccentricity; The number of cycles in which the air gap length changes; The angular velocity of the translator is 3 revolutions. This refers to the mechanical angle in the circumferential direction; For time.

[0037] The theoretical cancellation rate of this embodiment is 100%, but in actual engineering, residual couples may occur due to manufacturing tolerances and slight asynchrony between the two stages. To suppress residual couples, an axial gap is provided between the two-stage composite generators, and flexible damping supports are provided at the ends of the composite generators. By optimizing the axial gap between the two stages and adding flexible damping supports, residual couples can be effectively suppressed.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation, characterized in that: Includes stator, translational rotor, and external rotor; The stator includes a stator core and a multiphase concentrated winding wound on the stator core, with the central axis of the stator core being the main axis O1; The translational actuator has a ring-shaped structure and includes a magnetically conductive yoke and a first permanent magnet. The magnetically conductive yoke is ring-shaped, and the first permanent magnet is attached to the outer wall of the magnetically conductive yoke along the circumferential direction. The central axis of the translational actuator is the translational actuator axis O2, which is parallel to the main axis O1. The translational actuator is eccentrically fitted onto the outside of the stator with an eccentricity e. There is a non-uniform internal air gap between the translational actuator and the stator. The translational actuator performs a circular translational motion around the main axis O1 without rotating around the translational actuator axis O2. The minimum air gap point of the non-uniform internal air gap moves continuously along the circumferential direction of the stator as the translational actuator moves. The translational actuator and the stator constitute a radial variable reluctance power generation structure. The motion of the translational actuator induces an electromotive force on the multiphase concentrated winding. The outer rotor is used to connect with the fluid kinetic energy harvesting impeller; the outer rotor is sleeved on the outside of the translational rotor and shares the same main shaft O1 with the stator; a second permanent magnet is attached to the inner wall of the outer rotor along the circumferential direction; there is a non-uniform external air gap between the outer rotor and the translational rotor; the outer rotor and the translational rotor form a cycloidal magnetic gear structure; the rotation of the outer rotor is converted into the motion of the translational rotor through magnetic field coupling and cycloidal magnetic gear effect; the translational rotor can transmit torque to an external generator.

2. The cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation as described in claim 1, characterized in that: It also includes a crankshaft support mechanism that restricts the motion of the translational element; the crankshaft support mechanism includes at least three crankshafts, which are axially connected to the translational element; each crankshaft includes a main journal, crank arms, and crank pins connected in sequence, the main journals are evenly distributed around the main shaft O1, and the main journals are supported on a fixed end cover by bearings, the crank pins are evenly distributed around the translational element axis O2, and the crank pins are supported on the translational element by bearings, the length of the crank arms is equal to the eccentricity e, the crank arms are parallel to each other and have the same phase, constraining the translational element to perform circular translational motion around the main shaft O1 without rotating around the translational element axis O2, the circular translational motion of the translational element is converted into the rotation of the crankshaft by the crankshaft support mechanism, and at least one of the main journals transmits torque to an external generator.

3. The cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation as described in claim 2, characterized in that: The end face of the translator has outwardly protruding boss bearing seats evenly distributed along the circumferential direction, and the crank pin is supported in the boss bearing seats by bearings.

4. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation as described in claim 1, characterized in that: The number of pole pairs of the first permanent magnet is pt, and the number of pole pairs of the second permanent magnet is pr, and pr > pt, and the two satisfy pr - pt = 1; the gear transmission ratio i = pr / (pr - pt) = pr, and the gear transmission ratio ranges from 60 to 150.

5. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation as described in claim 1, characterized in that: The stator core is evenly provided with 3 stator teeth along the circumferential direction. The multiphase concentrated winding is a three-phase double-layer fractional slot concentrated winding with a winding pole pair number ps = 1 and a number of slots per pole per phase number q = 0.

5.

6. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation as described in claim 1, characterized in that: A counterweight is fixedly installed on the translator. The counterweight is installed on the opposite eccentric side of the magnetic yoke, so that the center of mass of the translator assembly coincides with the main shaft O1.

7. A cycloidal magnetic gear composite generator for low-speed hydrodynamic power generation as described in any one of claims 1-6, characterized in that: The low-speed fluid kinetic energy power generation cycloidal magnetic gear composite generator adopts an axial double-stage symmetrical layout. The eccentricity directions of the two stages of the translational rotors differ by 180°. The two stages share the same outer rotor. The orbital frequencies and speeds of the two stages of the translational rotors are the same, while the eccentricity directions are opposite.

8. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy generation as described in claim 7, characterized in that: An axial gap is provided between the two stages of the low-speed hydrodynamic power generation cycloidal magnetic gear composite generator, and the axial gap and / or the end of the low-speed hydrodynamic power generation cycloidal magnetic gear composite generator are provided with flexible damping supports to suppress residual torque.

9. A cycloidal magnetic gear composite generator for low-speed fluid kinetic energy power generation as described in claim 1, wherein the low-speed shaft of the fluid kinetic energy harvesting impeller is coaxially connected to the outer rotor, and the fluid kinetic energy harvesting impeller is a wind turbine for wind power generation or a water turbine for tidal energy generation.

10. A cycloidal magnetic gear composite generator for low-speed hydrodynamic power generation as described in any one of claims 1-6 and 8-9, characterized in that: The fluid kinetic energy harvesting impeller drives the outer rotor to rotate at low speed. Coupled by the cycloidal magnetic gear structure, the translational rotor performs a circular translational motion. On one hand, the crankshaft output end of the translational rotor serves as a high-speed mechanical output port. On the other hand, it causes the reluctance of the non-uniform inner air gap to change periodically, inducing an electromotive force in the multiphase concentrated winding. The crankshaft output end of the translational rotor is connected to the external generator, forming the main power output channel. The external generator is a permanent magnet synchronous generator. The radial variable reluctance generator structure operates in switched reluctance generator mode via an asymmetric half-bridge power converter, forming an auxiliary power output channel. The main power output channel and the auxiliary power output channel share a DC bus, and after merging, they are connected to the power grid via an inverter.

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