CN113131705A

CN113131705A - Cup-shaped winding permanent magnet synchronous motor, energy storage flywheel and method

Info

Publication number: CN113131705A
Application number: CN202110461404.0A
Authority: CN
Inventors: 徐衍亮; 孙铭鑫
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2021-07-16
Anticipated expiration: 2041-04-27
Also published as: CN113131705B

Abstract

The utility model provides a cup-shaped winding permanent magnet synchronous machine, energy storage flywheel and method, synchronous machine collects motor and generator as an organic whole, and work is at electronic and two kinds of states of electricity generation, realizes electronic, the reciprocal operation of electricity generation, includes: the rotor comprises an outer rotor, a cup-shaped winding and an inner rotor, wherein the cup-shaped winding is arranged in a cavity between the inner rotor and the outer rotor, the outer rotor comprises an outer rotor yoke, the inner rotor comprises an inner rotor yoke, and air gaps are reserved between the outer rotor and the cup-shaped winding and between the cup-shaped winding and the inner rotor. The present disclosure simplifies the structure of the flywheel energy storage system. The motor has the advantages of simple structure, improved energy utilization efficiency, shortened axial length, reduced overall size and weight, and contribution to stable rotation of the rotor.

Description

Cup-shaped winding permanent magnet synchronous motor, energy storage flywheel and method

Technical Field

The disclosure belongs to the technical field of motors, and particularly relates to a cup-shaped winding permanent magnet synchronous motor, an energy storage flywheel and a method.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

With the rapid development of economy, the power consumption demand of users is increasing, the energy demand is also increasing, the contradiction between the supply and demand of energy is becoming severe, and the requirements of users on the reliability and flexibility of energy are gradually increasing. In order to realize sustainable high-quality development of low-carbon green energy, especially due to continuous promotion of renewable energy technology, the proportion of renewable energy such as wind energy, solar energy and the like in power generation is gradually increased. However, due to the intermittency and randomness of the renewable energy, in order to realize efficient utilization of the energy and improve the power supply reliability, the high proportion of the renewable energy provides higher requirements for the aspect of energy storage, and new opportunities are brought to the development of the energy storage.

The energy storage literally means the storage of electric energy, the energy storage technology is a more effective method for coping with energy shortage, meeting the requirements of stable and sustainable operation of a power grid and efficiently utilizing energy at present, in a power system, when the load of the power grid fluctuates, various energy storage devices play a role in carrying out certain peak clipping and valley filling, when the power demand is less and the power load of the power grid is in a low valley state, the energy storage devices acquire the electric energy from the power grid for charging, and redundant electric energy is stored in the devices; when the power demand is more and the power grid can not meet the power supply, the energy storage device feeds back the stored electric energy to the power grid, so that the power demand of a user is met. In addition, the energy storage technology can be used in renewable energy power generation occasions, can effectively store energy with strong randomness, such as wind energy, solar energy and the like, improves the energy utilization rate and grid-connected reliability of renewable energy power generation during grid connection, and has great promotion effect on the development of renewable energy power generation in the future.

At present, common energy storage modes mainly include three major types, namely physical energy storage, chemical energy storage and other energy storage modes, wherein the three major types include flywheel energy storage, pumped storage power station, thermal energy storage, compressed air energy storage and the like, which belong to the physical energy storage, and the most common types include battery energy storage, capacitor energy storage and the like, which belong to the category of chemical energy storage, and other modes also include superconducting energy storage and the like. At present, the most widely used method is battery energy storage, a battery is used as an energy source, stable voltage and current can be obtained, and the battery is simple in structure, convenient to carry and low in one-time investment cost. The energy storage range of the battery is wide, and the battery is suitable for various large, medium and small energy storage occasions from a lead storage battery to various dry batteries and lithium batteries, and is widely applied to the fields of renewable energy sources such as new energy automobiles, solar power generation and the like. However, the large-scale application of the chemical battery can generate a large amount of carbon emission, and can cause serious environmental pollution over time, so that the flywheel energy storage technology is more and more emphasized by the industry for the sustainable development of the society, and has a bright development prospect.

The flywheel energy storage is an energy storage mode which has the advantages of high charging and discharging efficiency, long service life, high energy density, high power density, high starting speed, no limit of charging and discharging times, strong adaptability to working temperature and operating environment, low maintenance cost and no pollution, and gradually becomes a research hotspot at present. Due to the unique advantages, the flywheel energy storage can be widely applied to the fields of new energy grid connection, aerospace, transportation, Uninterruptible Power Supply (UPS) and the like, and can be jointly applied to a wind power generation system together with battery energy storage. The flywheel energy storage has the working principle that energy conversion between electric energy and mechanical energy is realized, a flywheel rotating at a high speed is used as an energy storage medium, and when charging is needed, the motor is used for driving the flywheel to rotate at a high speed, so that the electric energy is converted into mechanical kinetic energy to be stored; when discharging is needed, the flywheel is used for dragging the generator to generate electricity, the flywheel decelerates, kinetic energy is converted into electric energy, and power is supplied to a load.

As early as a hundred years ago, it was proposed to store energy using a flywheel rotating at high speed, but this idea has not been practically developed due to the limitations of the state of the art at that time. Until the 60 s in the 20 th century, the U.S. space agency tried to use flywheel energy storage as a satellite battery, and then the demand for the flywheel energy storage of the satellite was increasing in various countries, and the flywheel was continuously used in the military industry, national defense, aerospace and other occasions. In recent years, with the rapid development of the following three related technologies, the flywheel energy storage technology is brought with a great development prospect, and firstly, the high-strength carbon fiber composite material is produced, so that the rotating speed and the strength of the flywheel are improved, and the kinetic energy storage capacity of unit mass is increased; the research on the magnetic suspension technology and the high-temperature superconducting technology is rapidly developed, and the magnetic suspension technology and the vacuum technology are combined, so that the friction loss and the wind friction loss of a flywheel rotor are greatly reduced; thirdly, the development of a novel motor and a novel power conversion device leads various new progresses of the modern power electronic technology to emerge endlessly, and provides a more advanced means for the energy conversion of flywheel energy storage. Since research on flywheel energy storage is started earlier abroad, developed countries such as the united states, germany, japan, and the like have many developments and applications of flywheel energy storage technology, and a lot of research and production have been carried out by many units and enterprises such as the national aeronautics and astronautics administration (NASA), Active Power company, beller company in germany, and the like. China starts late in the field of flywheel energy storage, and domestic teams engaged in flywheel energy storage research mostly belong to academic institutions such as universities and scientific research institutes, such as Qinghua university, Beijing aerospace university, Chinese academy of electrical industry, Harbin industry university, Shandong university and the like, but with the support of the country on the new energy field in recent years, related enterprises also engage in the production research of flywheel energy storage aspects, such as Jidong development group, Beijing Qifeng energy collection technology limited company, Beijing Huachi pool kinetic energy technology limited company and the like, but compared with foreign high-performance energy storage flywheels, the foreign energy storage flywheels have larger gaps mainly in the aspects of reliability, capacity and the like.

The basic structure of the flywheel energy storage system mainly comprises five parts, namely a flywheel body for storing energy, a motor/generator set, a bearing system for supporting, a power electronic conversion system and a vacuum chamber. In order to reduce the friction loss caused by high-speed rotation of the flywheel, the flywheel body and the motor are sealed in the vacuum chamber, so that the wind resistance loss of the motor during operation is reduced, the energy utilization rate of a flywheel energy storage system is improved, and the safety of the system is ensured. In order to improve the flexibility and the adaptability of the flywheel energy storage system and enable the electric energy generated by the flywheel energy storage system to be used under various voltage levels on different occasions, the power electronic conversion device is applied to the flywheel energy storage system. The power electronic conversion device is used as a medium for exchanging energy between the motor and the external load side electrical equipment in the flywheel energy storage system, can realize the bidirectional flow of energy between the flywheel energy storage system and the external electrical equipment, regulates the voltage, the current and the frequency of output/input electric energy, and converts the electric energy output by the flywheel through frequency modulation, rectification or constant voltage and other electric power, thereby meeting the electric energy required by load power supply. The flywheel body is used as the most core part in a flywheel energy storage system, is usually made of high-strength carbon fiber composite materials, and has the function of storing energy and directly determining the amount of the stored energy, so that the design of the flywheel generally strives to improve the rotating speed or the rotational inertia, and meanwhile, the energy storage capacity of the flywheel is increased under the condition of ensuring certain weight of the flywheel. The bearing system is an important mechanical component for maintaining the stability and the reliability of the flywheel system, mainly comprises a mechanical bearing and an electromagnetic bearing, and is mainly applied to the flywheel energy storage system at present, the electromagnetic bearing, namely a magnetic suspension system, is mostly adopted, so that the motor rotor has no friction and mechanical loss, and the service life of the flywheel is prolonged. The motor/generator set is a core component for realizing energy conversion of the flywheel, in order to ensure stable operation of a flywheel energy storage system, the motor must be capable of realizing reciprocal operation of electric operation/power generation, namely the motor and the generator are integrated and can work in two states of electric operation and power generation, when energy is stored, the motor operates as the motor, and external electric energy is utilized to drive the motor to drive the flywheel rotor to rotate at a high speed so as to store the electric energy; when releasing energy, the motor operates as a generator, the flywheel decelerates to drive the generator to generate electricity and output electric energy outwards. In order to ensure that the energy storage flywheel can obtain better performance, the following performance requirements should be met for the motor/generator set: the motor can run at high speed so as to reserve higher capacity, the motor has wide speed regulation range, good speed regulation performance, high running efficiency, large output torque, high output power, simple structure, reliable performance and the like. Common motors for flywheel energy storage include asynchronous motors, permanent magnet synchronous motors, switched reluctance motors, inductor motors, and the like. The permanent magnet synchronous motor is simple in structure, high in efficiency and widely applied at present. Permanent magnet synchronous motors are diverse in types, and can be divided into an outer rotor permanent magnet synchronous motor and an inner rotor permanent magnet synchronous motor according to different rotor positions, can be divided into a radial magnetic flux type, an axial magnetic flux type and a transverse magnetic flux type according to different magnetic circuit directions, and can be divided into an iron core type motor and an iron core-free type motor according to different stator structures, and the like.

Different types of motors have different characteristics and are suitable for different occasions, at present, many research prototypes of permanent magnet motors for energy storage flywheels are available at home and abroad, particularly, the research on the permanent magnet motors for the energy storage flywheels is very mature at home and abroad, the NASA in the United states deeply researches the motor performances of 5 different permanent magnet structures of a high-speed permanent magnet motor/generator for a flywheel energy storage system, and the Halbach outer rotor coreless high-speed permanent magnet brushless direct current motor of a permanent magnet structure is researched by the university of Sheffield and south-Korea and is applied to a flywheel energy storage device of an electric automobile. The research of the permanent magnet motor for the energy storage flywheel in China starts late, a built-in permanent magnet synchronous motor is designed by the institute of electricians in the Chinese academy of sciences for adjusting the voltage fluctuation of a power grid, and a permanent magnet brushless motor with an outer rotor and an ironless Halbach magnet structure is designed in 2004 of Shandong university and Beijing aerospace university, and part of the permanent magnet brushless motor is designed to be made into a prototype and applied to a domestic flywheel energy storage system.

At present, the demand of permanent magnet synchronous motors for energy storage flywheels in the energy field of wind power generation, aerospace and the like is increasing day by day, so that higher and more urgent requirements are provided for the research and application of the permanent magnet synchronous motors for the energy storage flywheels. In spite of previous work, the flywheel permanent magnet motor produced in China has a large gap with similar products abroad mainly in the aspects of capacity, power density, utilization efficiency and the like, and cannot be effectively popularized and used. Therefore, a new motor structure needs to be designed on the basis of the most common permanent magnet synchronous motor, and meanwhile, due to the particularity of the application occasions, the structure and the like of the energy storage flywheel, in order to finally realize industrialization and commercialization of the energy storage flywheel and ensure the safety and the reliability of the energy storage flywheel, the new motor structure needs to mainly solve the following problems:

1. research and development of a prototype with a new structure and optimization design of a motor structure. According to the requirements of an energy storage flywheel on compact structure, large capacity and excellent performance of a permanent magnet motor, a novel vertically-installed cup-shaped winding permanent magnet synchronous motor adopting a radial magnetic flux principle is developed and developed so as to expand the variety of motors for the energy storage flywheel and widen the application range of the radial magnetic flux cup-shaped winding permanent magnet synchronous motor. The radial magnetic flux cup-shaped winding permanent magnet synchronous motor structure is optimized, so that the motor structure is simpler, the manufacturing is convenient, the motor process difficulty is reduced, the motor size is reasonably designed, the weight is reduced, and the volume is reduced.

2. The position and the installation of the motor on the energy storage flywheel are problems. Because the motor utilizes the forged steel of the flywheel rotor, the flywheel casing and the magnetic suspension bearing component of the existing energy storage flywheel to determine the position of the motor in a flywheel system on the basis of the known dimensional relationship, the accurate determination of the position of the motor is the key for ensuring the safe and reliable operation of the flywheel. In addition, the problem of installation of the motor is to be solved, and because the flywheel rotates at a high speed, the motor needs to ensure that each part of the motor cannot deviate along with the rotation of the flywheel in the actual installation process, so that the installation is accurate and firm, and the safety of the energy storage flywheel is ensured.

3. And (4) optimizing the loss of the motor. When the permanent magnet synchronous motor runs at a high speed, eddy current loss, iron core loss and the like can be generated, the loss can generate a large amount of heat on a stator and a rotor of the motor and is not easy to dissipate, and the safety of the motor and a flywheel cannot be guaranteed. Therefore, the reduction of the loss of the motor has very important significance on the safety and the reliability of the flywheel, and the motor has no iron loss theoretically because of no stator iron core, so that the iron-core-free motor is the research and development direction of the future flywheel motor.

Disclosure of Invention

In order to overcome the defects of the prior art, the cup-shaped winding permanent magnet synchronous motor is provided, compared with the traditional permanent magnet synchronous motor, the cup-shaped winding permanent magnet synchronous motor is more suitable for occasions of an energy storage flywheel, and under the same rated power and rated voltage, the cup-shaped winding permanent magnet synchronous motor is small in size, light in weight, high in efficiency and small in loss.

In order to achieve the above object, one or more embodiments of the present disclosure provide the following technical solutions:

in a first aspect, a cup winding permanent magnet synchronous motor is disclosed, which integrates a motor and a generator, works in two states of electric operation and power generation, and realizes the reciprocal operation of electric operation and power generation, comprising:

the rotor comprises an outer rotor, a cup-shaped winding and an inner rotor, wherein the cup-shaped winding is arranged in a cavity between the inner rotor and the outer rotor, the outer rotor comprises an outer rotor yoke, the inner rotor comprises an inner rotor yoke, and air gaps are reserved between the outer rotor and the cup-shaped winding and between the cup-shaped winding and the inner rotor.

The outer rotor is composed of an outer rotor yoke and multi-pole permanent magnets which are distributed along the circumferential direction and have N poles and S poles which are staggered, wherein the permanent magnets are uniformly distributed on the inner surface of the outer rotor yoke according to the required number of poles of the magnetic poles.

According to a further technical scheme, the permanent magnet is installed in a mode that: directly placing the permanent magnet on the inner wall of the periphery of the cavity formed in the end face of the flywheel rotor; or

The permanent magnet is firstly arranged on the inner wall of a magnetic conduction cylinder and then integrally arranged on the inner wall of the periphery of the cavity formed in the end face of the flywheel rotor.

According to a further technical scheme, each pole of permanent magnet is of a fan-shaped structure and is magnetized in the radial direction;

preferably, each pole of permanent magnet is divided into a plurality of small blocks along the axial direction and the circumferential direction, and the small blocks are bonded together and then are magnetized in the radial direction integrally.

In a further technical scheme, the material used by the outer rotor yoke of the motor is magnetically conductive flywheel steel, and the fan-shaped permanent magnet is made of a rare earth permanent magnet material with excellent performance.

In a further technical scheme, the inner rotor is a permanent magnet inner rotor or a non-permanent magnet inner rotor;

preferably, the permanent magnet inner rotor is composed of an inner rotor yoke and multipolar permanent magnets which are arranged and uniformly distributed along the circumference direction of the inner rotor yoke along the N poles and the S poles in a staggered manner;

preferably, each permanent magnet of the permanent magnet sector structure is wholly and radially magnetized after being partitioned and is made of rare earth permanent magnet materials;

further preferably, the non-permanent magnet inner rotor has only one inner rotor yoke and no permanent magnet is arranged on the outer side of the inner rotor;

the inner rotor yoke is also made of magnetic-conductive flywheel steel.

In a further technical scheme, the inner rotor yoke and the outer rotor yoke rotate synchronously and are part of a large flywheel rotor, and the magnetic conduction flywheel rotor is used as the outer rotor yoke and the inner rotor.

According to the further technical scheme, the cup-shaped winding is formed by curing an armature winding of a motor stator through epoxy resin, is wound on a stator support made of non-magnetic and non-conductive materials, is filled with the epoxy resin, and is finally integrally fixed on a supporting disc at the upper end of the motor.

According to the technical scheme, the cup-shaped winding is fixed with a non-magnetic-conductive snap ring through bolts, a winding coil and a stator support which are filled with epoxy resin are fixed with the non-magnetic-conductive snap ring through the bolts, the snap ring is buckled on the outer side of the winding filled with the epoxy resin and placed at the upper end of the stator support, the side end of the cup-shaped winding is fixed with the winding coil filled with the epoxy resin through axial and radial bolts, the bottom of the cup-shaped winding is fixed with the stator support through axial bolts, and the upper portion of the cup-shaped.

According to the further technical scheme, the outer periphery of the supporting disc at the upper end is fixed on the inner periphery of the flywheel stator casing, the inner periphery of the supporting disc at the upper end is fixed with the outer periphery of the upper radial magnetic bearing, and the bottom of the supporting disc at the upper end is connected with the winding fixing retaining ring through bolts and clamping grooves.

In a second aspect, an energy storage flywheel is disclosed, wherein the energy storage flywheel adopts the permanent magnet synchronous motor to perform electromechanical energy conversion;

the motor is arranged in an annular cavity formed in the upper end face of the flywheel rotor, the magnetic conduction flywheel rotor is used as an outer rotor yoke and an inner rotor, and the cup-shaped winding is arranged in the cavity;

the axial length of the permanent magnet of the magnetic conduction flywheel rotor is larger than the length of the linear part of the winding coil, namely, the end part of the winding coil interacts with the permanent magnet to generate electromotive force except the effective length of an armature core of the linear part of the coil.

In a third aspect, a method of operating a cup-winding permanent magnet synchronous machine is disclosed, comprising:

the main magnetic circuit air gap comprises an outer air gap between the outer rotor permanent magnet and the cup-shaped winding and an inner air gap between the cup-shaped winding and the inner rotor;

the permanent magnetic flux sequentially passes through the outer rotor permanent magnet, the outer air gap, the winding, the inner air gap, the inner rotor permanent magnet, the inner rotor yoke, the adjacent inner rotor permanent magnet, the inner air gap, the winding, the outer air gap, the adjacent outer rotor permanent magnet and the outer rotor yoke and finally returns to the original outer rotor permanent magnet to form a closed loop.

The polarity of two adjacent permanent magnets along the circumferential direction is opposite, when a rotor of a prime mover rotates, a permanent magnet magnetic pole serves as the rotor to generate a synchronous rotating magnetic field, a three-phase stator winding reacts through an armature under the action of the rotating magnetic field to induce three-phase symmetrical current, at the moment, the kinetic energy of the rotor is converted into electric energy, and the permanent magnet synchronous motor serves as a generator;

when three-phase symmetrical alternating current is introduced into the stator windings, the three-phase stator windings are 120 degrees different from each other in spatial position, so that three-phase stator current generates a synchronous speed rotating magnetic field in space, the synchronous speed rotating magnetic field interacts with a magnetic field generated by the permanent magnet to generate synchronous electromagnetic torque, the rotor synchronous rotating magnetic field is acted by electromagnetic force to generate relative motion, the motor is driven to rotate, at the moment, the electric energy of the motor is converted into the kinetic energy of the rotor, and the permanent magnet synchronous motor is used as a motor.

The above one or more technical solutions have the following beneficial effects:

1. the novel motor working principle and the novel motor structure are adopted, the motor radially flows magnetic flux, the winding is a hollow cup-shaped winding and has no stator iron core, the motor and the generator are integrated, the motor/power generation reciprocal operation is realized, the motor/power generation two-state flywheel energy storage system can work in the motor state and the power generation state, and the structure of the flywheel energy storage system is simplified. The motor has the advantages of simple structure, improved energy utilization efficiency, shortened axial length, reduced total volume and weight, contribution to stable rotation of the rotor, expanded types of motors for the energy storage flywheel, widened application range of the radial magnetic flux cup-shaped winding permanent magnet synchronous motor, and flexible application in more occasions.

2. The present disclosure addresses the problems of rotor structure and strength. The flywheel can generate great centrifugal force when rotating at high speed, and for more permanent magnet motors, the permanent magnet on the rotor is easy to fall off under the action of the centrifugal force of high-speed rotation, so the present disclosure adopts a solid outer rotor structure, the motor is arranged in an annular cavity formed on the upper end surface of the flywheel rotor, the permanent magnet can be directly arranged on the inner wall of the periphery of the cavity formed on the end surface of the flywheel rotor, and a magnetic conductive sleeve can be manufactured, the permanent magnet is firstly arranged on the inner wall of the sleeve and then integrally arranged on the inner wall of the periphery of the cavity formed on the end surface of the flywheel rotor, the mechanical matching mode between an outer rotor yoke and the magnetic conductive sleeve is interference fit, therefore, the outer rotor yoke can play a role of blocking the permanent magnet when the flywheel rotates at high speed, besides, the permanent magnet blocks are favorable for reducing the bending stress applied to the permanent, the radial flux motor has no axial magnetic pull force, and the radial position of the cup-shaped winding can be ensured not to change due to the rotation of the flywheel by utilizing the upper end supporting disk for connecting the flywheel casing and the radial magnetic bearing and the non-magnetic-conductive fixing part at the upper end of the winding, so that the strength of the rotor is enough to ensure, and the reliability of the flywheel is greatly increased.

3. The present disclosure solves the problem of loss optimization of electric machines. When the permanent magnet synchronous motor runs at a high speed, stator core loss, copper loss on a winding and eddy current loss on a rotor can be generated, wind friction loss, mechanical friction loss and the like are also generated, the losses can generate a large amount of heat on a stator and a rotor of the motor and are not easy to dissipate, and the safety of the motor and a flywheel cannot be guaranteed. The whole flywheel is vacuumized, so that the wind mill loss on the surface of the rotor of the high-speed permanent magnet motor is effectively and greatly reduced; the motor has no stator core, so that stator core loss can not exist theoretically, meanwhile, the permanent magnet is fixed on the rotor and does not move relative to the rotor core, the permanent magnet is partitioned, and eddy current loss hardly exists in the iron core theoretically; the motor is supported by the magnetic suspension bearing, and mechanical friction loss between the motor and a common mechanical bearing is eliminated, so that the reduction of the loss of the motor has very important significance on the safety and reliability of the flywheel, the energy utilization rate of a flywheel energy storage system is greatly improved, the service life of the motor is prolonged, and a new direction is provided for the research and development of future flywheel motors.

4. The flywheel energy storage motor solves the problem of temperature rise heat dissipation of the motor, and due to the fact that the flywheel energy storage motor is high in rotating speed and large in capacity, very high temperature rise can be brought, and heat dissipation cannot be achieved. The hollow cup-shaped winding structure is independent of the rotor core, and has two air gaps, so that enough space is provided for laying a copper pipeline in the winding for air cooling and water cooling, and heat dissipation is facilitated.

5. The motor mounting and processing technology is simplified. The position and the size of a motor in a flywheel system are determined on the basis of the known size relation on the basis of the forged steel of a flywheel rotor, a flywheel shell and a magnetic suspension bearing component of the conventional energy storage flywheel, so that the material of the motor can be greatly saved, and the internal space of the flywheel can be more reasonably utilized; the installation can adopt the modularization assembly thinking during the installation, vertical installation, and the installation order is cup-shaped winding in the middle of earlier, and then confirms the permanent magnet mounted position according to the axial height of winding, and the cavity size that needs to open out of at last according to both sizes confirms the flywheel rotor, and the installation degree of difficulty greatly reduced has improved the reliability and the integrated level of system.

6. The torque output characteristic of the motor is better. The motor adopts a stator tooth-groove-free structure, so that the tooth-groove torque and the tooth harmonic of the motor can be eliminated, the positioning torque of the motor is zero, the output torque characteristic of the motor is better, and the stability of a rotor is favorably improved.

7. Compared with the traditional permanent magnet synchronous motor for flywheel energy storage, the vertically-installed cup-shaped winding permanent magnet synchronous motor has the advantages of convenience in design and calculation, simple structure, light weight, small size, low loss, high efficiency and the like.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

FIG. 1 is an overall three-dimensional block diagram of an embodiment of the present disclosure;

FIG. 2 is a three-dimensional structural view of a motor body portion according to an exemplary embodiment of the present disclosure;

FIG. 3 is a schematic view of an assembled electric machine according to an exemplary embodiment of the present disclosure;

FIG. 4 is a schematic view of a flywheel rotor according to an embodiment of the present disclosure;

fig. 5 is a structural view of an outer rotor yoke according to an embodiment of the present disclosure;

6(a) -6 (b) are block diagrams of permanent magnet inner and non-permanent magnet rotors of an embodiment of the present disclosure;

FIGS. 7(a) -7 (b) are block diagrams of a single permanent magnet and a whole permanent magnet according to an embodiment of the present disclosure;

FIGS. 8(a) -8 (b) are a single winding diagram and a one-piece cup winding structure diagram of an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a winding fixing component according to an exemplary embodiment of the disclosure

FIG. 10 is a diagram illustrating a structural relationship between permanent magnets and windings according to an exemplary embodiment of the present disclosure;

FIG. 11 is a stator coil wiring diagram of an embodiment of the present disclosure;

FIG. 12 is a schematic diagram of a main magnetic circuit of a motor according to an embodiment of the present disclosure;

fig. 13 is a sectional view showing a structural positional relationship of a motor according to an embodiment of the present disclosure;

in the figure, an upper end cover 1, a radial magnetic bearing 2, a machine shell 3, a bearing supporting disk 4, an outer rotor yoke 5, an inner rotor yoke 6, a rotating shaft 7, a permanent magnet pole 8, a cup-shaped winding 9, a winding fixing retaining ring 10, a lower end cover 11, a flywheel rotor 12 and a stator support 13.

For convenience of describing a magnetic circuit, the permanent magnets are divided into an outer rotor permanent magnet 8-1, an adjacent outer rotor permanent magnet 8-2, an inner rotor permanent magnet 8-3 and an adjacent inner rotor permanent magnet 8-4 (a non-permanent inner rotor does not exist).

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict.

Example one

The embodiment discloses a vertically-mounted cup-shaped winding permanent magnet synchronous motor for an energy storage flywheel, taking an 8-pole 72-slot cup-shaped winding permanent magnet synchronous motor as an example, when the vertically-mounted cup-shaped winding permanent magnet synchronous motor for flywheel energy storage is used in the present disclosure, a structural position relation cross-sectional view of the motor in a flywheel system is shown in fig. 13, in order to accurately describe the mutual relation between the components in the system and the cup-shaped winding permanent magnet synchronous motor when used as the flywheel energy storage system, the approximate positions of the components involved, including an end cover, a casing, a radial magnetic bearing and the like, need to be slightly illustrated, and therefore the overall structure of the vertically-mounted cup-shaped winding permanent magnet synchronous motor in the flywheel energy storage system is shown in fig. 1 (here, including other non-motor body components.

Fig. 2 shows the motor body part of the invention, the motor body is divided into three parts of an inner rotor 6, a cup-shaped winding 9 and an outer rotor 5, the cup-shaped winding is arranged in a cavity between the inner rotor and the outer rotor, and air gaps are reserved between the outer rotor and the middle cup-shaped winding and between the middle cup-shaped winding and the inner rotor.

In one embodiment, the intermediate cup-shaped winding 9, which is made up of 72 single-turn coils, is wound on a stator support made of a non-magnetic and non-conductive material and filled with epoxy resin, and finally is integrally fixed to the radial magnetic bearing support disk 4 at the upper end of the motor, since the motor has no stator core.

In a specific embodiment, the outer rotor is composed of an outer rotor yoke 5 and eight permanent magnets 8 with staggered N poles and S poles in the circumferential direction, wherein the permanent magnets 8 are uniformly distributed on the inner surface of the outer rotor yoke according to the required number of poles of magnetic poles, the polarities of two adjacent permanent magnets in the circumferential direction are opposite, the permanent magnets are in a fan-shaped structure and are magnetized in the radial direction, in order to facilitate installation and reduce loss, each permanent magnet needs to be divided into a plurality of small blocks in the axial direction and the circumferential direction in actual manufacturing, and then the small blocks are bonded together and are magnetized in the overall radial direction, the structure of the outer rotor yoke 5 is given by fig. 5, and the structure diagram of the permanent magnets 8 is shown in fig. 7, wherein fig. 7a is a structure diagram of; the inner rotor 6 may be a permanent magnet inner rotor or a non-permanent magnet inner rotor, and the structure of the permanent magnet inner rotor is shown in fig. 6a, and the structure of the non-permanent magnet inner rotor is shown in fig. 6 b.

Specifically, the permanent magnet inner rotor is composed of an inner rotor yoke and multi-pole permanent magnets, N poles and S poles of the inner rotor yoke are distributed on the outer side of the inner rotor yoke in a staggered mode along the circumferential direction, the permanent magnets are the same as the outer rotor permanent magnets in the same installation mode and are of a fan-shaped structure, the permanent magnets are magnetized in the radial direction after being divided into blocks, and the permanent magnets are made of rare earth permanent magnet materials; the non-permanent magnet inner rotor has no permanent magnet and only one inner rotor yoke outside.

As shown in the motor assembly diagram of fig. 3, the motor is disposed in an annular cavity formed in the upper end surface of the flywheel rotor 12, and the cup-shaped winding 9 is disposed in the cavity by using the magnetic conductive flywheel rotor as the outer rotor yoke 5 and the inner rotor 6; the structural relationship between the permanent magnet 8 and the winding 9 is shown in fig. 10, and the axial length of the permanent magnet 8 is required to be larger than the length of the linear part of the coil of the winding 9; except the effective length of the armature core of the linear part of the coil, the end part of the winding coil can be interacted with the permanent magnet to generate electromotive force, so that the space waste caused by overlong winding end part and incapability of utilizing is avoided, the axial length of the motor is greatly shortened, the weight of the winding is reduced, and the supporting strength of the winding is ensured.

The installation schematic diagram of the permanent magnet 8 is shown in the figure, one method is to directly place the permanent magnet 8 on the inner wall of the periphery of the cavity opened on the end face of the flywheel rotor 12, the other method is to place the permanent magnet 8 on the inner wall of a cylinder firstly and then place the whole body on the inner wall of the periphery of the cavity opened on the end face of the flywheel rotor 12, and the mechanical fit mode between the outer rotor yoke and the magnetic conduction sleeve is interference fit.

The winding fixing part is structurally schematically shown in fig. 9, a middle cup-shaped winding 9 is wound on a non-magnetic and non-conductive stator support 13, after epoxy resin is filled, a winding coil 9 and the stator support 13 filled with the epoxy resin are respectively fixed with a non-magnetic retaining ring 10 through bolts, wherein the inner diameter and the outer diameter of the retaining ring 10 are the same as those of the stator support 13, the side end of the retaining ring is fixed with the winding coil 9 filled with the epoxy resin through axial and radial bolts, the bottom of the retaining ring is fixed with the stator support 13 through the axial bolts, and the upper part of the retaining ring is fixed with an upper end supporting disc 4 through the axial.

It should be noted that the outer diameter of the motor must not exceed the outer diameter of the flywheel rotor, the axial height of the motor must be smaller than the height of the flywheel rotor, the motor is placed in an annular cavity formed in the upper end face of the flywheel rotor, and the magnetic conduction flywheel rotor is used as an outer rotor yoke and an inner rotor, so that the thickness of the outer rotor yoke should not be too small to ensure the supporting strength.

The cup windings are placed in the cavities, with the inner rotor yoke and the outer rotor yoke rotating synchronously, both being part of a large flywheel rotor. Enough space should be left between middle cup-shaped winding and the interior outer rotor, guarantee that the winding can not be because of the circumference magnetic pull force is inhaled on the interior outer rotor, also leave sufficient space for epoxy's filling simultaneously.

The full slot ratio of the cup-shaped winding needs to be less than 50%, the full slot ratio is as small as possible under the condition of meeting the current density and the output characteristic, and as the capacity of the energy storage flywheel is large, the copper consumption generated by the armature winding can bring a large amount of heat which can not be dissipated, so that air cooling or water cooling needs to be carried out inside the motor. In contrast, water cooling is more effective than air cooling, so that the upper end and the inner space of the armature winding are coiled with a copper water pipe for water cooling.

The current materials of the inner and outer rotor yokes of the motor are magnetic flywheel steel, and the fan-shaped permanent magnet is made of rare earth permanent magnet materials with excellent performance.

The installation sequence of the motor is that the position and the size of the middle cup-shaped winding are firstly determined, the middle cup-shaped winding is fixed on the upper end supporting disc through the bolt piece and the suspension piece on the upper part of the winding, the axial height and the installation position of the permanent magnet are determined according to the axial height of the winding (the permanent magnet is required to be ensured not to influence the fixation of the winding), and finally the size of a cavity which needs to be opened by the flywheel rotor is determined according to the two sizes.

The air gaps mentioned in the main magnetic circuit comprise an outer air gap a between the outer rotor permanent magnet and the middle cup-shaped winding and an inner air gap b between the middle cup-shaped winding and the inner rotor, the main magnetic circuit of the motor is specifically represented by adding figure 12, and two air gaps in one main magnetic circuit are labeled.

The working principle of the motor of the present disclosure is explained with reference to fig. 3 and 12: the permanent magnetic flux forms a closed loop through the outer rotor permanent magnet 8-1 → the outer air gap a → the winding 9 → the inner air gap b → the inner rotor permanent magnet 8-3 (the non-permanent inner rotor does not) → the inner rotor yoke 6 → the adjacent inner rotor permanent magnet 8-4 (the non-permanent inner rotor does not) → the inner air gap b → the winding 9 → the outer air gap a → the adjacent outer rotor permanent magnet 8-2 → the outer rotor yoke 5 → and finally returns to the original outer rotor permanent magnet 8-1.

The polarities of two adjacent permanent magnets in the circumferential direction are opposite, when a rotor of a prime mover rotates, a permanent magnet magnetic pole 8 serves as the rotor to generate a synchronous rotating magnetic field, a three-phase stator winding 9 reacts through an armature under the action of the rotating magnetic field to induce three-phase symmetrical current, at the moment, the kinetic energy of the rotor 12 is converted into electric energy, and the permanent magnet synchronous motor serves as a generator; when stator winding 9 lets in three-phase symmetrical alternating current, because three-phase stator winding is 120 each other on spatial position, so three-phase stator current produces synchronous fast rotating magnetic field in the space, and the magnetic field interact that produces with permanent magnet 8 produces synchronous electromagnetic torque, receives the electromagnetic force effect in the rotor 12 synchronous rotating magnetic field, can produce relative motion, and then the driving motor is rotatory, and the motor electric energy converts rotor kinetic energy into this moment, and permanent magnet synchronous machine uses as the motor.

The wiring mode of the motor winding is as shown in fig. 11 (only the wiring mode of the winding of the phase a is listed, B, C phases are the same, and three phases are mutually different by 120 °), and the stator winding 9 is a short-moment distributed winding and is arranged in double layers along the radial direction, and a central line is led out.

Compared with the permanent magnet motor with the traditional structure for the energy storage flywheel, the integral motor with the remarkable advantages is greatly reduced in overall size. The large solid rotor of the flywheel occupies a large space in the whole flywheel energy storage system, the traditional motor for the energy storage flywheel does not use the flywheel rotor as a part of the motor, and the space in the flywheel cannot be reasonably utilized. The novel vertically-installed cup-shaped winding permanent magnet synchronous motor is reasonably utilized, the motor is arranged in an annular cavity formed in the upper end face of the flywheel rotor, the magnetic conduction flywheel rotor is used as an outer rotor yoke and an inner rotor, and the cup-shaped winding is arranged in the cavity, so that the overall size of the motor is reduced, and the space utilization maximization is realized. Another significant advantage of the present disclosure is that the motor losses are small, efficiency is high, the stator part of the motor has no stator core, the cogging torque and the tooth harmonics of the motor and the eddy current losses on the stator can be eliminated, meanwhile, the interior of the flywheel is evacuated, the wind friction losses are eliminated in a vacuum environment, and the mechanical losses caused by the mechanical bearings are eliminated by the use of the electromagnetic bearings, i.e., the magnetic bearings. The novel vertically-installed cup-shaped winding permanent magnet synchronous motor provided by the disclosure enables the efficiency and energy utilization rate of a flywheel energy storage system to be higher.

The middle cup-shaped winding is suspended between the inner rotor and the outer rotor, is wound on a stator support made of non-magnetic and non-conductive materials, is filled with epoxy resin, and is fixed on an upper end supporting disc through a bolt piece and a suspension piece in the upper end part of the winding.

The motor of the technical scheme is integrated with the motor and the generator, can realize the reciprocal operation of electric/power generation, and can work in two states of electric and power generation; the motor is arranged in an annular cavity formed in the upper end face of the flywheel rotor, the magnetic conduction flywheel rotor is used as an outer rotor yoke and an inner rotor, and the cup-shaped winding is arranged in the cavity; the axial length of the permanent magnet is greater than the length of the linear part of the winding coil, so that the axial length of the motor is shortened, the weight of the winding is reduced, the types of the motors for the energy storage flywheel and the application occasions of vertically installing the permanent magnet synchronous motor are expanded, the iron loss of the motor is greatly reduced, the torque characteristic and the heat dissipation effect of the motor are better, and the permanent magnet generator is suitable for the occasions of high-capacity flywheel energy storage wind power generation.

Example II

The specification discloses a working method of a novel vertically-installed cup-shaped winding permanent magnet synchronous motor, which comprises the following steps:

the air gap mentioned by the main magnetic circuit comprises an outer air gap between the outer rotor permanent magnet and the middle cup-shaped winding and an inner air gap between the middle cup-shaped winding and the inner rotor;

the permanent magnetic flux sequentially passes through the outer rotor permanent magnet, the outer air gap, the winding, the inner air gap, the inner rotor permanent magnet, the inner rotor yoke, the adjacent inner rotor permanent magnet, the inner air gap, the winding, the outer air gap, the adjacent outer rotor permanent magnet and the outer rotor yoke and finally returns to the original outer rotor permanent magnet to form a closed loop;

the polarities of two adjacent permanent magnets in the circumferential direction are opposite, when a rotor of a prime mover rotates, the permanent magnet magnetic poles serve as the rotor to generate a synchronous rotating magnetic field, a three-phase stator winding reacts through an armature under the action of the rotating magnetic field to induce three-phase symmetrical current, at the moment, the kinetic energy of the rotor is converted into electric energy, and the permanent magnet synchronous motor serves as a generator; when three-phase symmetrical alternating current is introduced into the stator windings, the three-phase stator windings are 120 degrees different from each other in spatial position, so that three-phase stator current generates a synchronous speed rotating magnetic field in space, the synchronous speed rotating magnetic field interacts with a magnetic field generated by the permanent magnet to generate synchronous electromagnetic torque, the rotor synchronous rotating magnetic field is acted by electromagnetic force to generate relative motion, the motor is driven to rotate, at the moment, the electric energy of the motor is converted into the kinetic energy of the rotor, and the permanent magnet synchronous motor is used as a motor.

The cup winding usually cannot rotate too high and a bearing with low bearing capacity can be used for the support. The axial length of the flywheel rotor is large, so that the mode of the flywheel rotor is influenced, and the axial length of the motor needs to be compressed; the rotor has large loss, high heat and difficult dissipation, and the temperature rise needs to be reduced by adopting permanent magnet blocking, SMC materials and other modes; the thickness of the permanent magnet can not be infinitely increased along with the increase of the power of the motor, and the iron core structure is introduced to reduce the magnetic resistance of a magnetic circuit under the limitation of the thickness, so that the use of permanent magnet materials is saved.

Compared with the traditional permanent magnet synchronous motor, the synchronous motor in the embodiment of the disclosure is more suitable for occasions of the energy storage flywheel, and under the same rated power and rated voltage, the cup-shaped winding permanent magnet synchronous motor is small in size, light in weight, higher in efficiency and smaller in loss, thereby being the development direction of the motor for the energy storage flywheel in the future.

It is to be understood that throughout the description of the present specification, reference to the term "one embodiment", "another embodiment", "other embodiments", or "first through nth embodiments", etc., is intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, or materials described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.

Claims

1. A cup-shaped winding permanent magnet synchronous motor is characterized in that the synchronous motor integrates a motor and a generator, works in an electric state and a power generation state, realizes the reciprocal operation of the electric state and the power generation state, and comprises:

2. The cup-winding permanent magnet synchronous motor according to claim 1, wherein said outer rotor is comprised of an outer rotor yoke and multi-pole permanent magnets having N-poles and S-poles alternately arranged in a circumferential direction, wherein the permanent magnets are uniformly distributed on an inner surface of the outer rotor yoke in accordance with a required number of poles.

3. The cup-winding permanent magnet synchronous motor of claim 1, wherein the permanent magnets are mounted in a manner that: directly placing the permanent magnet on the inner wall of the periphery of the cavity formed in the end face of the flywheel rotor; or

4. The cup-winding permanent magnet synchronous machine of claim 2, wherein each pole of permanent magnet is of a fan-shaped structure, and is radially magnetized;

5. The cup-winding permanent magnet synchronous motor according to claim 2, wherein the material of the outer rotor yoke of the motor is magnetically conductive flywheel steel, and the sector permanent magnets are made of a rare earth permanent magnet material having excellent properties.

6. The cup winding permanent magnet synchronous motor of claim 1 wherein said inner rotor is a permanent magnet inner rotor or a non-permanent magnet inner rotor;

the inner rotor yoke is also made of magnetic-conductive flywheel steel.

7. The cup-winding permanent magnet synchronous motor of claim 1, wherein the inner rotor yoke and the outer rotor yoke rotate synchronously and are part of a large flywheel rotor, and the outer rotor yoke and the inner rotor are implemented by using a magnetically permeable flywheel rotor.

8. A cup-wound permanent magnet synchronous machine as claimed in claim 1, wherein said cup-winding is formed by epoxy curing of the armature winding of the stator of the machine, the winding being wound on a stator support made of a material which is non-conducting and non-conducting, and filled with epoxy and finally integrally fixed to a support disc at the upper end of the machine.

Preferably, the cup-shaped winding is fixed with a non-magnetic conductive snap ring through a bolt for a winding coil and a stator support filled with epoxy resin, the snap ring is buckled on the outer side of the winding filled with epoxy resin and placed at the upper end of the stator support, the side end of the cup-shaped winding is fixed with the winding coil filled with epoxy resin through an axial and radial bolt, the bottom of the cup-shaped winding is fixed with the stator support through an axial bolt, and the upper part of the cup-shaped winding is fixed with an upper end supporting disc through an axial bolt and a clamping groove.

Preferably, the periphery of the supporting disc at the upper end is fixed on the inner periphery of the flywheel stator casing, the inner periphery of the supporting disc at the upper end is fixed with the outer periphery of the upper radial magnetic bearing, and the bottom of the supporting disc at the upper end is connected with the winding fixing retaining ring through bolts and clamping grooves.

9. An energy storage flywheel, characterized in that the energy storage flywheel adopts the permanent magnet synchronous motor of any one of the claims 1-8 to perform electromechanical energy conversion;

10. A method of operating a cup-wound permanent magnet synchronous machine as claimed in any of claims 1 to 8, comprising: