CN102437701A - Shore-based sea wave generator - Google Patents

Abstract

A shore-based wave generator comprises a vertically arranged annular stator and a mover arranged on the axis of the stator, wherein a stator coil slot is arranged on the outer surface of the stator, and an initial pole three-phase winding is embedded in the stator coil slot, and the mover comprises a mover shaft, a substrate surrounding the mover shaft, and a Halbach array permanent magnet surrounding the substrate, wherein the Halbach array permanent magnet comprises at least one group of permanent magnet arrays, each group of permanent magnet arrays comprises four annular permanent magnets arranged in sequence in the axial direction, and an air gap is arranged between the inner surface of the stator and the Halbach array permanent magnet. The present invention replaces the traditional permanent magnet with the Halbach array permanent magnet, which not only reduces the cost of the permanent magnet material, but also makes the generated magnetic field more sinusoidal and has a stronger magnetic induction intensity.

Description

A shore-based wave generator

technical field

The invention relates to a shore-based ocean wave generator for ocean wave power generation.

Background technique

Waves have enormous energy. It is not difficult to see the huge energy in it from the fact that tsunamis can wash ships onto land and even overturn buildings on the shore. Wave energy is a water energy resource expressed in the form of kinetic energy. Some scientists once estimated that the power of wave energy is as high as 2.0×100,000 kilowatts on a surface of 1 square kilometer. If we can make reasonable use of wave energy and convert the kinetic energy of wave energy into electrical energy, this energy will not only have large reserves and be pollution-free. , and it is renewable energy, which is inexhaustible and inexhaustible. In addition, my country is a big ocean country, and the available marine resources are extremely rich.

The wave generator uses the up and down vertical displacement of the waves as the power to drive the generator mover to convert water energy into electrical energy. The generated electrical energy is first sent to the substation on the shore, and then sent to the power grid after boosting.

In a traditional linear motor, the magnetization direction of the permanent magnet is perpendicular to the air gap and the magnetization direction between adjacent magnets rotates. Due to symmetry, the magnetic field is symmetrical on both sides of the permanent magnet array. With the Halbach type permanent magnet array, it is easy to obtain a magnetic field with an ideal sinusoidal distribution in space, which can greatly reduce the cogging torque of the motor. Even if the number of permanent magnet segments per pole is small (for example, 3 segments, or even 2 segments), a magnetic field distribution similar to that of an ideal Halbach-type permanent magnet array can be easily obtained. The above characteristics make the cogging moment of the motor adopting the Halbach type permanent magnet array almost negligible, which is beneficial to improve the performance of the motor. This feature also shows that the cost of manufacturing such a high-performance motor is not high, because the ideal sinusoidal distribution of the magnetic field can be obtained by using a Halbach-type array with a small number of segments, and using a simple winding and non-sloped stator and rotor structures.

Cylindrical permanent magnet linear generators can be divided into radial magnetization structure, axial magnetization structure and Halbach array (Halbach) magnetization structure according to the arrangement of the mover permanent magnets;

The permanent magnet array with radial magnetization structure requires magnetic conduction at the choke part of the mover, and its efficiency is low, and its magnetic density is mainly concentrated at the permanent magnet as shown. It is difficult to get a sinusoidal magnetic field. The magnetic field of the permanent magnet array with the axial magnetization structure is evenly distributed in the upper and lower directions of the radial direction. The axial magnetization structure has higher requirements on the air gap. When the air gap is small, the permanent magnet has a higher utilization rate. , when the air gap increases, the flux leakage will increase significantly, and the performance indicators such as power density and efficiency will decrease significantly. Therefore, the axial magnetization structure is not suitable for application in large-gap linear motors, and its air-gap flux density is also very Difficult to achieve sine. In practical applications, it is difficult to achieve an ideal Halbach magnetized array, so in practical applications, it is composed of segmented magnets, and each piece of permanent magnets under each pole is arranged in a certain direction, which is approximately equivalent to an ideal Halbach array.

The mover of Patent No. 201020163714 "a permanent magnet linear generator" is composed of a mover core and a non-magnetic material placed in the mover core slot, but the magnetic induction and sine of the magnetic field are insufficient.

Electric excitation linear motors have excitation loss, which reduces the overall efficiency; ironless permanent magnet linear motors have the advantages of small magnetic resistance, high positioning accuracy, and can provide horizontal and vertical driving forces at the same time, but because there is no ferromagnetic material to form a magnetic circuit , there are disadvantages of low air gap magnetic flux density and insufficient pulsation force.

Contents of the invention

Technical problem: The present invention aims at the deficiencies and defects of the prior art, and provides a shore-based wave generator that makes the magnetic field have better sinusoidal properties and stronger magnetic induction.

Technical solution: A shore-based wave generator, including a vertically arranged annular stator and a mover arranged on the axis of the stator. The outer surface of the stator is provided with a stator coil slot, and the initial pole is embedded in the stator coil slot. Three-phase winding, the mover includes a mover shaft, a base plate surrounding the mover shaft, and a Halbach array permanent magnet surrounding the base plate; the Halbach array permanent magnet includes at least one set of permanent magnet arrays, and each set of permanent magnet arrays includes four moving along Ring-shaped permanent magnets arranged in sequence in the sub-axial direction, the magnetization directions of each group of permanent magnet arrays are arranged in the same order, and the magnetization directions of the four ring-shaped permanent magnets in each permanent magnet array are radially inward and axially inward from bottom to top. Up, radially outward, axially down, or axially up, radially outward, axially down, radially inward, or radially outward, axially down, radially inward, axially upward, or axially downward, radially inward, axially upward, and radially outward; there is an air gap between the inner surface of the stator and the permanent magnets of the Halbach array.

In the present invention, the air gap is a gap of 0.5 to 1 cm between the inner surface of the stator and the permanent magnets of the Halbach array.

The permanent magnet linear synchronous motor for ocean wave power generation of the present invention is based on the shore-based ocean wave power station, and uses the ocean wave to impact the permanent magnet mover of the generator to move up and down, cut the stator winding of the linear motor to generate induced electromotive force, and then use the frequency conversion device to The frequency of the linear generator is converted into the power frequency, and the electricity can be transmitted to the user or the power grid;

In the present invention, when the secondary pole winding is not moving, there is a static magnetic field generated by a permanent magnet in the air gap of the linear motor. This magnetic field is sinusoidally distributed according to the linear direction, and the stator winding has no current passing through it. When the sea waves come, the permanent magnet is pushed up and down. Movement, in principle, is basically similar to the rotary motor, the difference is that the magnetic field of the linear motor translates along the linear direction, and the stator winding cuts the magnetic induction line to generate an induced electromotive force. When the external circuit is closed, the linear motor transmits electric energy to the external circuit .

Beneficial effects: the magnetic field of the present invention is provided by permanent magnets, so no excitation current passes through, reducing copper loss; because there are no excitation windings, slip rings and brushes, the reliability is improved, and the probability of short circuit or open circuit is reduced; Because the excitation magnetic field of the permanent magnet motor does not require winding and insulation work, the space occupied by the magnetic poles is greatly reduced, and a greater magnetic field strength can be obtained in a smaller space area; because the motor works in sea waves, the motor's Heat dissipation and cooling are very efficient.

Since the permanent magnet linear synchronous motor uses permanent magnets instead of electric excitation, there is no excitation loss. Therefore, the efficiency of the permanent magnet linear synchronous motor is higher than that of the electric excitation linear synchronous motor, and there is no need to draw the lagging excitation current from the grid, thus greatly improving the overall efficiency of the motor;

The secondary pole permanent magnet of the present invention is composed of Halbach array permanent magnets, and the permanent magnet array of Halbach array permanent magnets is magnetized according to the direction shown in Figure 2, so that the magnetic field has better sinusoidality, stronger magnetic induction intensity, and can increase the air gap Magnetic flux density; because there is no third harmonic in the strong side magnetic field, the pulsation of electromagnetic force can be greatly reduced. The present invention replaces the traditional rotary generator with a linear motor, without contact drive, reduces dielectric loss, and improves power generation efficiency; and replaces traditional permanent magnets with Halbach permanent magnets, which not only reduces the cost of permanent magnet materials, but also makes the generated The magnetic field is more sinusoidal and the magnetic induction is stronger.

The mover of the present invention adopts a permanent magnet structure covered with a substrate, and does not use iron core materials. Due to the unilateral magnetic field distribution generated by the self-shielding effect of the Halbach magnet, it is no longer necessary for the mover to use magnetic materials to provide a path for it, so that the system has a lower moment of inertia and better fast response performance;

Compared with the traditional permanent magnet motor structure, due to the mutual superposition of the parallel magnetic field and the radial magnetic field after the Halbach magnetic ring is decomposed, the magnetic field strength on the other side is greatly improved, which can effectively reduce the volume of the motor and increase the power of the motor density;

In traditional permanent magnet motors, due to the inevitable existence of harmonics in the air gap magnetic field, inclined slots are generally used on the stator structure to weaken its influence. In the Halbach motor, due to the high degree of sinusoidal distribution of the air gap magnetic field and the small harmonic content, the stator does not need a chute;

Since the permanent magnet operating point of the Halbach permanent magnet is relatively high, generally exceeding 0.9, the utilization rate of the permanent magnet is improved;

Distributed windings are often used in traditional permanent magnet motors to weaken the influence of harmonic magnetomotive force. In Halbach motors, due to the high degree of sinusoidal distribution of the magnetic field, the influence of harmonic magnetic fields is small, so the wave generator of the present invention can use centralized type winding;

The invention adopts the magnet arrangement of the Halbach motor, which greatly reduces the requirement on the bearing of the motor; can withstand the impact of sea waves, is not easy to be damaged; does not produce toxic gas, has no additional noise, and is environmentally friendly and healthy.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a schematic diagram of an axial section of a permanent magnet linear motor of the present invention. the

Fig. 2 is a three-dimensional sectional view of the permanent magnet linear motor of the present invention, and the arrow in the figure shows the magnetization direction of the permanent magnet. the

Figure 3 shows the radial magnetization structure of the Halbach permanent magnet.

Figure 4 shows the axial magnetization structure of the Halbach permanent magnet.

Figure 5 is the ideal magnetization structure of the Halbach permanent magnet.

Fig. 6 is the Halbach permanent magnet magnetization structure adopted in the present invention.

In the figure, there are: stator 1, stator coil slot 2, Halbach array permanent magnet 3, mover shaft 4, substrate 5, air gap 6, initial pole three-phase winding 7.

Detailed ways

As shown in Figure 1, the shore-based wave generator mainly includes the following parts: stator 1, stator coil slot 2, Halbach array permanent magnet 3, mover shaft 4, base plate 5, air gap 6, initial pole three-phase winding 7.

Embodiment 1: The shore-based ocean wave generator of the present invention includes a vertically arranged annular stator 1 and a mover arranged on the axis of the stator 1. The stator 1 is formed by laminating magnetically conductive steel sheets to enhance the magnetic field in the air gap Density, the outer surface of the stator 1 is provided with a stator coil slot 2, and the stator coil slot 2 is embedded with a parallel primary three-phase winding 7, and the primary three-phase winding 7 is wound with enameled wire to form a concentrated winding; the mover includes the mover Axis 4, substrate 5 surrounding mover shaft 4, and Halbach array permanent magnet 3 surrounding substrate 5, Halbach array permanent magnet 3 is pasted on substrate 5 with epoxy resin, and the substrate is formed by stamping non-magnetic stainless steel to enhance Robustness and reliability when the mover works; the Halbach array permanent magnet 3 includes at least one set of permanent magnet arrays, each set of permanent magnet arrays includes four ring-shaped permanent magnets arranged in sequence along the mover axis, and each set of permanent magnet arrays The order of the magnetization direction is the same. The magnetization direction of the four ring-shaped permanent magnets in each permanent magnet array is radially inward, axially upward, radially outward, and axially downward. There is a gap of 0.5 cm between the Halbach array permanent magnets 3 and the inner surface of the stator 1 .

Embodiment 2: The magnetization directions of the four annular permanent magnets in each permanent magnet array are axially upward, radially outward, axially downward, and radially inward from bottom to top. The Halbach array permanent magnet 3 and There is a gap of 0.8 cm between the inner surfaces of the stator 1, and the others are the same as in Embodiment 1.

Embodiment 3: The magnetization directions of the four annular permanent magnets in each permanent magnet array are radially outward, axially downward, radially inward, and axially upward from bottom to top. The Halbach array permanent magnet 3 and There is a gap of 0.6 cm between the inner surfaces of the stator 1, and the others are the same as in Embodiment 1.

Embodiment 4: The magnetization directions of the four annular permanent magnets in each permanent magnet array are axially downward, radially inward, axially upward, and radially outward from bottom to top, and the Halbach array permanent magnet 3 and There is a gap of 1 cm between the inner surfaces of the stator 1. In addition, two drainage grooves are set on both sides of the bottom of the generator. The seawater that leaks to the top of the mover through the air gap will leak out through the drainage grooves, which will not affect the use of the equipment. Others are the same as embodiment 1.

After the invention is installed in place, the bottom of the generator is fixed in the corresponding pipeline. When the seawater rises, the seawater rises to a certain position through the pipeline and then pushes the mover to move upward; when the seawater falls, the mover falls by its own gravity, so that the mover follows The rise and fall of the sea water reciprocates up and down, so that the magnetic field generated by the permanent magnet moves up and down, which is equivalent to the stator coil cutting the magnetic induction line. The current is generated in the stator coil, which is not a current of a certain frequency due to factors such as the unstable frequency of rising and falling sea water. It needs to be converted into a power frequency by a frequency conversion device, and the converted current can be delivered to the user. use or feed into the grid.

Claims (2)

1. A shore-based ocean wave generator, characterized in that the ocean wave generator includes a vertically arranged annular stator (1) and a mover arranged on the axis of the stator (1), and the outer surface of the stator (1) Stator coil slots (2) are arranged on the surface, and primary pole three-phase windings (7) are embedded in the stator coil slots (2). The mover includes a mover shaft (4) and a The substrate (5) and the Halbach array permanent magnet (3) surrounding the substrate (5); the Halbach array permanent magnet (3) includes at least one set of permanent magnet arrays, and each set of permanent magnet arrays includes four A ring-shaped permanent magnet arranged in sequence along the axial direction of the mover. The magnetization directions of each group of permanent magnet arrays are arranged in the same order. The magnetization directions of the four ring-shaped permanent magnets in each permanent magnet array are radially inward from bottom to top. , axially upward, radially outward, axially downward, or axially upward, radially outward, axially downward, radially inward, or radially outward, axially downward, radially inward , axially upward, or axially downward, radially inward, axially upward, and radially outward; there is an air gap (6) between the inner surface of the stator (1) and the Halbach array permanent magnet (3) . 2. The shore-based wave power generation device according to claim 1, characterized in that the air gap (6) is 0.5 to 1 cm between the inner surface of the stator (1) and the Halbach array permanent magnet (3) Clearance.

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