CN113131706B

CN113131706B - Disc type permanent magnet synchronous motor, energy storage flywheel and method

Info

Publication number: CN113131706B
Application number: CN202110459898.9A
Authority: CN
Inventors: 徐衍亮; 孙铭鑫; 李根胜
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2022-04-29
Anticipated expiration: 2041-04-27
Also published as: CN113131706A

Abstract

The disclosure provides a disc type permanent magnet synchronous motor, an energy storage flywheel based on magnetic suspension support and a method, wherein the method comprises the following steps: an upper stator disk and a lower rotor disk; the stator disc comprises a stator core, the stator core comprises two parts of stator teeth and a stator yoke, the armature winding is a short-moment distributed winding and is wound on the stator teeth, and winding coils are arranged in a double-layer mode along the axial direction; the rotor disk is composed of a rotor yoke disk and permanent magnets which are arranged in a staggered mode along the circumferential direction of N poles and S poles, wherein the number of the magnetic poles of the permanent magnets is evenly embedded on the upper surface of the rotor yoke. The structure of the motor for the energy storage flywheel is optimized, the motor is an axial flux motor, the flywheel rotor is used as a magnetic yoke disc of the rotor disc at the lower end, the motor and the generator are integrated, the reciprocal operation of electric/power generation is realized, the motor can work in two states of electric and power generation, and the structure of a flywheel energy storage system is simplified.

Description

Disc type 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 disc type permanent magnet synchronous motor, an energy storage flywheel based on magnetic suspension support 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 society, people consume more and more energy, the electricity consumption of users also increases year by year, the environmental pollution caused by the traditional thermal power is serious day by day, and people are forced to think about the feasibility of research and application by adopting new energy or renewable energy. In recent years, the country greatly supports low-carbon renewable energy sources, the renewable energy technology is greatly developed, and green energy sources such as wind energy, solar energy and the like become energy sources which are generally regarded by various countries. However, renewable energy sources such as wind energy, solar energy and the like have high randomness and are easily influenced by natural environment, and in order to realize efficient and flexible application of the renewable energy sources, energy storage is particularly important in this respect, and meanwhile, new opportunities and new directions are brought to the development of energy storage technology.

The energy storage technology can efficiently utilize energy, make up for the fluctuation of renewable energy power generation and improve the operation stability of a new energy grid-connected system aiming at the existing energy shortage. Energy memory can use in the electric wire netting, when there is the fluctuation in the load, energy memory can carry out the peak clipping in a certain extent and fill out the millet, when the power consumption demand of load is less, energy memory charges, can store the unnecessary electric energy that the electricity generation sent in energy memory, when the power consumption demand of load is very big, the electricity that the electric wire netting sent is not enough to provide sufficient electric power, energy memory discharges, the electric energy with the storage is to the electric wire netting repayment, thereby satisfy the power consumption demand of load. The energy storage system is combined with renewable energy sources such as wind power and photoelectricity, so that the autonomous peak and frequency regulation capacity of the energy storage system can be effectively improved, the consumption rate of the renewable energy sources is improved, and the development and utilization of novel renewable energy sources in the future are facilitated.

Currently, the most common energy storage methods in the power industry include physical energy storage methods such as pumped storage, flywheel energy storage, compressed air energy storage, and thermal energy storage, chemical energy storage methods such as battery energy storage and capacitor energy storage, and new superconducting energy storage, and the like, wherein chemical battery energy storage is still the most important energy storage method because of its simple structure and portability. But the chemical battery has small power and capacity, poor safety and short service life, and the recovery treatment mode of the waste battery is expensive and is easy to cause irreparable pollution to the environment. In recent years, with the enhancement of environmental awareness of people, the national attention on sustainable development is higher and higher, and more fields select the energy storage mode of storing energy by utilizing the flywheel, so that the energy storage device has incomparable advantages compared with the traditional chemical battery energy storage, and has a great development prospect.

The flywheel energy storage technology has the advantages of high energy storage density, high power density, high charge and discharge efficiency, short charge and discharge time, no limit of charge and discharge times, long service life, strong adaptability to working temperature and operating environment, low maintenance cost, no pollution and the like, and the research and application of the technology are embodied in the fields of electric power peak regulation and frequency modulation, new energy grid connection, transportation, aerospace, uninterruptible power supplies and the like, and particularly have extremely important research values for energy conservation and environmental protection.

The flywheel energy storage technology starts in the last 50 th century abroad, and energy storage by utilizing a flywheel rotating at a high speed is proposed and expected to be applied to energy storage of electric vehicles, however, due to the limitation of the technical conditions at that time, the idea is only reflected in the conception stage and cannot be put into practice. Later along with the development of the technology, the NASA research of the U.S. space service administration applies the flywheel energy storage technology to the aerospace field, and the flywheel is applied to the satellite as the energy storage battery, so that the flywheel energy storage technology basically stays in the research and military level for a while. After the last 90 s, the tensile strength of the flywheel is increased and the energy storage capacity of the flywheel is also greatly increased along with the appearance of the high-strength carbon fiber composite material. Meanwhile, due to the development of the magnetic suspension technology and the high-temperature superconducting technology, the magnetic suspension bearing is applied to a flywheel energy storage system, and the mechanical friction loss caused by the original mechanical bearing is eliminated; the flywheel energy storage system is vacuumized, so that the wind friction loss of the flywheel is greatly reduced, and the flywheel energy storage efficiency is higher. With the advent of new power electronic devices, the circuit is more integrated and modularized, and the new structure of the motor and the breakthrough of the power electronic conversion technology make the flywheel energy storage technology have wider application range and more efficient energy utilization. After that, many foreign enterprises and units such as Rotonix, powerthu, Active Power, Beacon, and piler have continuously conducted a lot of research on flywheel energy storage technology and further developed to market production. The research on the flywheel energy storage technology in China starts late and develops slowly, only a few companies are engaged in the research and development work of flywheel energy storage production at present, the marketization process is slow, and most scientific research teams are colleges and universities such as Beijing aerospace university, Qinghua university, China academy of sciences, Shandong university and the like, and compared with foreign high-performance energy storage flywheels, the technology has a space for progress.

The flywheel energy storage system mainly comprises a flywheel body, a motor/generator set, a bearing supporting part and a power electronic conversion device, and the basic principle of the flywheel energy storage system is that a flywheel rotating at a high speed is used as an energy storage medium, and when charging is needed, an external motor is used for driving the flywheel to rotate at a high speed, so that electric energy is converted into mechanical kinetic energy to be stored; when power generation is needed, the flywheel rotating at a high speed is used for dragging the generator to generate power, the flywheel decelerates, kinetic energy is converted into electric energy, and current and voltage suitable for a load are output through the power converter to supply power to the load, so that the energy conversion and energy storage process between the electric energy and mechanical energy is completed. The power electronic conversion device provides energy exchange for a motor and external electrical equipment in the flywheel energy storage system, the flywheel is controlled to charge and discharge through the switching device and the control circuit, and the voltage, the current and the frequency of output/input electric energy are adjusted by adopting different topological structures, so that the bidirectional flow of the energy of the flywheel energy storage system and the external equipment is realized, and proper electric energy is provided for a load. The bearing support part is a part used for mechanically supporting a structure in the flywheel system and is often divided into a mechanical bearing and an electromagnetic bearing, because the mechanical bearing often brings mechanical friction loss and is difficult to maintain, the larger flywheel system and the larger flywheel system are supported by the electromagnetic bearing; magnetic suspension bearings are classified as electromagnetic bearings into radial magnetic bearings and axial magnetic bearings, wherein the radial magnetic bearings can maintain radial suspension of a rotor shaft as the name suggests, and the permanent magnet biased radial magnetic bearings, the electromagnetic radial magnetic bearings and the hybrid radial magnetic bearings are commonly used, and the axial magnetic bearings can maintain axial suspension of the rotor shaft and can be classified into active and passive axial magnetic bearings. The flywheel rotor is a core component of the whole flywheel system and is used for storing energy, and the energy storage capacity of the flywheel is improved by manufacturing the flywheel rotor by using a composite material capable of bearing higher rotating speed and rotating tension. The working principle of the energy storage flywheel is to realize the bidirectional flow of energy, so that the motor/generator set is a key part for energy conversion of the flywheel, the motor and the generator are integrated into a whole, and the energy storage flywheel has the characteristics of the motor and the generator. Nowadays electric machines for energy-storing flywheels often comprise: induction motors, permanent magnet motors, switched reluctance motors, homopolar motors, and the like, each of which has been studied in literature, wherein permanent magnet motors have high power density, high operating efficiency, simple structure, and good dynamic performance, and thus permanent magnet motors are the most popular motor type in flywheel energy storage systems. Because the rotor magnetic field of the permanent magnet motor is generated by the permanent magnet, the permanent magnet motor can be divided into a radial flux permanent magnet motor, a transverse flux permanent magnet motor and an axial flux permanent magnet motor according to different magnetizing directions of the permanent magnet.

The axial flux permanent magnet synchronous motor is also called a disc type permanent magnet synchronous motor, is widely concerned by domestic and foreign scholars by virtue of the characteristics of compact structure, high efficiency, high power density and the like, but has few precedent of being applied to an energy storage flywheel, and has a certain application prospect in a high-speed flywheel energy storage system in the future. The first motor in the world of faraday's invention was an axial flux motor, but was limited by the current material and process levels, and the axial permanent magnet motor had almost stalled for a considerable period of time thereafter, had not been effectively developed, and was gradually on the market by the radial flux motor. Later, with the appearance of new materials and the development of new technologies, the axial flux motor is rapidly developed by means of the advantages of high efficiency and high power density, and is gradually and widely applied to the fields of electric automobiles, wind power generation, aerospace, flywheel energy storage and the like.

The traditional disc type permanent magnet synchronous motor can be divided into a single-stator single-rotor structure, a double-rotor middle stator structure, a double-stator middle rotor structure and a multi-disc structure according to the number of stators and rotors and relative positions of the stators and the rotors. In the last 70 th century, the research on disc-type permanent magnet synchronous motors in foreign countries has gradually developed, and the feasibility of manufacturing disc-type permanent magnet synchronous motors was proposed for the first time by professor a bramanti of the university of pizza in italy. Although the starting is late in China, a certain research result is provided for the disc type permanent magnet synchronous motor, professor in Dong-ren profession of Tang proposes a detailed design method for the disc type permanent magnet synchronous motor, and university of Shenyang industry designs a prototype of the double-rotor disc type permanent magnet synchronous motor. In addition, the loss generated by the soft magnetic composite material and the amorphous alloy material under a high-frequency magnetic field is very small, so that experts and scholars at home and abroad choose to use the material to replace the traditional silicon steel sheet. With the increasing demand of the fields of wind power generation, aerospace and the like on the energy storage flywheel, the requirements on the research and application of the disc type permanent magnet synchronous motor for the energy storage flywheel are more strict. At present, the research on the disc type permanent magnet synchronous motor in China is not deep enough, and the disc type permanent magnet synchronous motor cannot be effectively popularized and used. Therefore, a new motor structure needs to be designed on the basis of the most common disc-type permanent magnet synchronous motor, new materials are utilized, new applications are developed, the coordination and the coordination with a flywheel energy storage system are emphasized, and meanwhile, due to the particularity of the application occasions, the structure and the like of the energy storage flywheel, in order to realize the industrialization and the commercialization of the energy storage flywheel and ensure the safety and the reliability of the energy storage flywheel, the following problems need to be considered in a key way in the new motor structure:

1. research and development of a prototype with a new structure and optimization design of a motor structure. Due to the requirements of the energy storage flywheel on the performances of the permanent magnet motor in the aspects of structure, capacity, efficiency, power and the like, a novel disc type permanent magnet synchronous motor adopting an axial magnetic flux principle is researched and developed so as to expand the types of motors for the energy storage flywheel and widen the application range of the disc type permanent magnet synchronous motor. Because disc motor structure variety is various, based on the magnetic suspension bearing support, can further optimize disc PMSM structure, carries out rational design to the motor size, makes motor structure simpler, and axial length is shorter, reduces the volume and the weight of motor, is convenient for make.

2. The position and the installation of the motor in 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, the position of the motor in a flywheel system is determined on the basis of the known dimensional relationship of the motor, and in order to ensure the reasonable utilization of space, 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 disc type permanent magnet synchronous motor is provided with a stator disc structure and a rotor disc structure, installation feasibility and installation sequence of motor parts are considered when the disc type permanent magnet synchronous motor is installed in the energy storage flywheel, coordination and matching of motor assembly and an energy storage flywheel system are guaranteed, under the condition that the flywheel rotates at a high speed, all elements of the motor are firmly installed in the actual installation process, the situation that the position of the motor is not moved due to high-speed rotation is guaranteed, and safe and stable operation of the energy storage flywheel is achieved.

3. The application of new materials in the disc type permanent magnet synchronous motor. Due to the special structure of the disc type permanent magnet synchronous motor, a motor magnetic circuit is a three-dimensional path, in addition, a stator core of the disc type permanent magnet synchronous motor is large in size and difficult to radiate heat, the motor can generate core loss at a stator yoke part, and the traditional silicon steel sheet material can generate large iron loss under high working frequency, so that the temperature rise of the stator yoke is large, and the safe operation of the motor is influenced. In order to solve these problems, the relevant scholars have conducted innovative studies from the material side. The soft magnetic composite material (SMC) is a novel magnetic conductive functional material, compared with the most common laminated silicon steel material, the SMC has the advantages of low high-frequency iron loss, isotropy, magnetocaloric property and the like, can realize the three-dimensional magnetic circuit structure, multi-pole high frequency and modular design of a motor when used for the motor, and has the advantages of high efficiency, high power density, low loss and the like. The soft magnetic composite material (SMC) is widely applied to the disc type permanent magnet synchronous motor, and is greatly helpful for improving the performance of the disc type permanent magnet synchronous motor for the energy storage flywheel.

4. The dynamic balance of the motor. Because the stator of the permanent magnet synchronous motor is simultaneously used as a magnetic loop of a rotating magnetic pole, the single-stator single-rotor disc type permanent magnet synchronous motor can generate single-side magnetic pull force, and in order to ensure the dynamic balance of the motor, a thrust bearing is required to be considered so as to ensure that the rotor cannot generate axial movement. Meanwhile, in order to prevent the radial electromagnetic force existing in the motor stator and cause the radial position of the stator disc and the rotor disc to have deviation, the radial magnetic bearing can be considered to be additionally arranged. Therefore, solving the dynamic balance problem of the motor is particularly important for the safe and stable operation of the motor, so that the disc type permanent magnet synchronous motor for the energy storage flywheel is indispensable to be supported based on a magnetic suspension bearing.

Disclosure of Invention

In order to overcome the deficiencies of the prior art, the present disclosure provides a disc-type permanent magnet synchronous motor, which can shorten the axial length of the motor, reduce the volume, reduce the weight, and obtain higher efficiency and higher power density based on the magnetic suspension bearing support.

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 disc-type permanent magnet synchronous motor is disclosed, comprising:

an upper stator disk and a lower rotor disk;

the stator disc comprises a stator core, the stator core comprises two parts of stator teeth and a stator yoke, an armature winding is a short-moment distributed winding and is wound on the stator teeth, and winding coils are arranged in a double-layer mode along the axial direction;

the rotor disc is composed of a rotor yoke disc and permanent magnets which are arranged in a staggered mode along the circumferential direction of N poles and S poles, wherein the number of the magnetic poles of the permanent magnets is evenly embedded on the upper surface of the rotor yoke.

According to the further technical scheme, the stator disc and the rotor disc are vertically arranged along the axial direction;

a radial magnetic bearing is arranged in the stator disc iron core to ensure the radial position, a flywheel rotor is used for replacing a rotor yoke disc, and an axial driven magnetic bearing is arranged at the lower part of the flywheel rotor to ensure the axial position.

According to the further technical scheme, when the permanent magnets of the rotor disc are manufactured, each permanent magnet pole is divided into a plurality of small blocks along the radial direction and the circumferential direction, so that the permanent magnets can be conveniently installed.

According to the further technical scheme, the outer diameter of the rotor yoke disc is slightly larger than that of the permanent magnet, the end face of the rotor inside the winding end range is lower than the upper surface of the permanent magnet but not more than half of the axial thickness of the permanent magnet, the end face of the rotor outside the winding end range, namely the end face of the rotor outside the permanent magnet, is flush with the upper surface of the permanent magnet, the coaxiality of the stator disc and the rotor disc of the motor is kept, and an air gap between the stator disc and the rotor disc is guaranteed through a size chain.

In a further technical scheme, the rotor yoke disc is made of magnetically conductive flywheel steel, the fan-shaped permanent magnet is made of rare earth materials, and the stator core is formed by combining soft magnetic composite SMC (sheet molding compound) molded core blocks.

In a second aspect, an energy storage flywheel is disclosed, which comprises the above disc type permanent magnet synchronous motor, wherein a non-magnetic conductive ring is arranged at the upper end of a stator core of the synchronous motor, the non-magnetic conductive ring and the stator core are adopted to form, and a stator disc and a radial magnetic bearing stator are assembled together through a magnetic conductive disc at the upper end.

According to the further technical scheme, the outer diameter and the inner diameter of the non-magnetic conductive ring are slightly larger than the inner diameter and the outer diameter of the stator core, and the non-magnetic conductive ring is tightly buckled on the top of the stator core through bolts in an interference fit mode.

According to the technical scheme, the inner periphery of the upper-end magnetic conduction disc is arranged on the casing of the radial magnetic bearing, the outer periphery of the upper-end magnetic conduction disc is fixed on the inner wall of the flywheel casing, the disc type motor is connected with the flywheel casing and the radial magnetic bearing through the magnetic conduction disc, the connection position is sealed through a rubber sealing ring, and an adjusting cushion block is required to be additionally arranged at the connection position of the magnetic conduction disc and the flywheel casing during assembly to ensure that the air gap of the motor is unchanged.

In a further technical scheme, the radial magnetic bearing, the flywheel shell and the magnetic disk are in interference fit mechanically, and the upper end of the magnetic disk is provided with a groove and a water pipe is laid for water cooling.

The motor is arranged between the flywheel casing and the radial magnetic bearing, the upper stator disc of the motor is arranged between the periphery of the upper radial magnetic bearing and the flywheel casing, the flywheel rotor is used as a magnetic conduction yoke disc of the lower rotor disc, the permanent magnet is embedded on the upper end face of the flywheel rotor, the maximum outer diameter of the outer end part of the winding of the motor stator disc is smaller than the inner diameter of the stator casing, and the inner diameter of the inner end part of the winding of the motor stator disc is larger than the outer diameter of the magnetic bearing.

In the further technical scheme, the attraction force of a stator disc at the upper end of the motor to a rotor disc needs an axial repulsive force of an axial passive magnetic bearing which is lower than 1/2 times, and an axial protection bearing is additionally arranged on the upper end shaft surface of a flywheel rotor so as to ensure an air gap of the motor;

in the further technical scheme, the axial passive magnetic bearing in the energy storage flywheel is arranged below a flywheel rotor and comprises two bearing discs, an upper movable bearing is fixed on the lower surface of the flywheel rotor, a lower static bearing disc is fixed with an end cover, and a proper air gap is reserved between the two bearing discs;

in a third aspect, a method for installing an energy storage flywheel is disclosed, which comprises the following steps:

firstly, the integral flywheel rotor is installed in place, the installation position of a stator disc is determined by measuring the axial position of a permanent magnet on the upper end face of the flywheel rotor, the axial clearance between the stator disc and the rotor disc of the motor is sequentially ensured, and in addition, the integral rotor is axially positioned to ensure that the rotor disc of the motor cannot be attached to the stator disc under the suction action of the stator disc;

in a fourth aspect, a working method of a disc type permanent magnet synchronous motor is disclosed, which includes:

the air gap mentioned in the main magnetic circuit is the air gap between the stator core and the rotor disc;

the polarities of two adjacent permanent magnets along the circumferential direction are opposite, when a rotor of a prime motor rotates, the permanent magnet magnetic poles serve as the rotor to generate a synchronous rotating magnetic field, magnetic flux in a stator core is alternated, a three-phase stator winding wound on the stator core induces induced electromotive force through armature reaction under the action of the rotating magnetic field, three-phase symmetrical current is generated in the winding, at the moment, the kinetic energy of the rotor is converted into electric energy, the permanent magnet synchronous motor serves as a generator, and the generated electric energy is converted into electric energy for a load;

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 rotating magnetic field in space, the synchronous 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:

the motor is applied to a new occasion, the structure of the motor for the energy storage flywheel is optimized, the motor is an axial flux motor, the flywheel rotor is used as a magnetic yoke disc of a rotor disc at the lower end, the motor and the generator are integrated, the motor/power generation reciprocal operation is realized, the motor/power generation reciprocal operation can work in two states of motor and power generation, and the structure of a flywheel energy storage system is simplified. The disc type permanent magnet synchronous motor adopts a single-stator disc and single-rotor disc structure, is matched with the radial magnetic bearing and the axial magnetic bearing for use, has a more compact structure under the condition of ensuring the reliable operation of the motor, shortens the axial length of the motor, reduces the total volume and weight of the motor, has better performance, is applied to the occasions of high-capacity flywheel energy storage, and provides a research direction for the development of future flywheel energy storage systems.

The present disclosure solves the dynamic balance problem of the motor. The stator and the rotor of the motor are distributed along the axial direction, because the stator of the motor is simultaneously used as a magnetic loop of a rotating magnetic pole, a stator disc at the upper end of a single-stator single-rotor disc type permanent magnet synchronous motor can generate unilateral magnetic pulling force to a rotor disc at the lower end, in order to ensure the dynamic balance of the motor, the disc type permanent magnet synchronous motor disclosed by the invention is based on magnetic suspension support, an axial passive magnetic bearing is arranged at the lower part of a flywheel rotor so as to ensure that the rotor cannot generate axial float, the attractive force of the stator disc at the upper end of the motor to the rotor disc needs an axial repulsive force which is lower than 1/2 times that of the axial passive magnetic bearing, and meanwhile, an axial protection bearing is additionally arranged on the axial surface at the upper end of the flywheel rotor so as to ensure that the air gap of the motor cannot be too small. In addition, in order to prevent radial electromagnetic force of a motor stator from causing deviation between the radial positions of a stator disc and a rotor disc, the disc type permanent magnet synchronous motor is arranged between a flywheel casing and a radial magnetic bearing casing, the axial height of the disc type permanent magnet synchronous motor is the same as that of a radial magnetic bearing, and a hybrid radial magnetic bearing is additionally arranged, so that the dynamic balance problem of the motor can be effectively solved, and the disc type permanent magnet synchronous motor has important significance for safe and stable operation of the motor.

The present disclosure addresses the problem of rotor strength. In the high-capacity energy storage flywheel, the flywheel is usually in a working state of high-speed rotation, and a great centrifugal force can be generated at the moment, and a rotor disc of the permanent magnet motor is usually provided with permanent magnet blocks to avoid the danger caused by the falling of the permanent magnets under the action of the centrifugal force, therefore, the permanent magnets on the rotor disc are embedded into the flywheel rotor, the outer diameter of the rotor yoke disc is slightly larger than that of the permanent magnets, the end face of the rotor inside the winding end range needs to be lower than the upper surface of the permanent magnet but not more than half of the axial thickness of the permanent magnet, the rotor yoke can block the permanent magnet when the flywheel rotates at high speed, and simultaneously, the permanent magnets are partitioned in the radial direction and the circumferential direction, so that the bending stress applied to the permanent magnets during high-speed rotation can be reduced, and the strength of the rotor and the safety of the motor are ensured.

The present disclosure broadens the application range of new materials. The rotor is in an axial magnetic flux structure, and a magnetic circuit of the motor is a three-dimensional magnetic circuit, namely the rotation direction of the rotor is perpendicular to the plane of a main magnetic circuit of the motor. And disc PMSM's stator core is great usually, can produce great iron loss with traditional silicon steel sheet material under higher operating frequency for the stator yoke temperature rise is great, consequently through adopting neotype soft magnetic composite, organizes into stator core with soft magnetic composite SMC moulded iron core group, can effectively solve the problem that disc PMSM faced, has widened soft magnetic composite range of application simultaneously, reaches the complementary effect that promotes of industry.

The motor mounting and processing technology is simplified. In order to greatly save the space occupied by the motor and reasonably utilize the internal space of the energy storage flywheel, the present disclosure 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 and the size of the motor in the flywheel system on the basis of the known size relationship, the motor is required to be arranged between the flywheel casing and the radial magnetic bearing, the stator disc at the upper end of the motor is arranged between the periphery of the radial magnetic bearing at the upper end and the flywheel casing, the flywheel rotor is used as the magnetic conduction yoke disc of the rotor disc at the lower end, the internal space of the flywheel is reasonably utilized, and the axial height of the motor is reduced; the motor is of a disc structure, the modularized assembly thought can be adopted during installation, the installation steps are that the integral flywheel rotor is installed in place firstly, the axial position of the permanent magnet on the upper end face of the flywheel rotor is measured, the installation position of the stator disc is determined, the axial gap between the motor stator disc and the rotor disc is ensured in sequence, then the integral rotor is axially positioned, a protection cushion block and a protection bearing are additionally installed under the condition of supporting based on a magnetic suspension bearing, the motor rotor disc is ensured not to be attached to the stator disc under the suction action of the stator disc, the installation process is reduced, and the reliability and the integration degree of a flywheel energy storage system are ensured.

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 diagram of a stator core structure according to an exemplary embodiment of the present disclosure;

6(a) -6 (b) are block diagrams of a single permanent magnet and a whole permanent magnet of an embodiment of the present disclosure;

FIG. 7 is a structural relationship diagram between permanent magnets and a rotor yoke disk of an embodiment of the present disclosure;

8(a) -8 (b) are single winding diagrams and overall armature winding structure diagrams of an embodiment of the present disclosure;

FIG. 9 is a stator assembly schematic of an embodiment of the disclosure

FIG. 10 is a stator coil wiring diagram of an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of a main magnetic circuit of a motor according to an embodiment of the present disclosure;

fig. 12 is a cross-sectional view of an electric machine embodying the present disclosure;

in the figure, an upper end cover 1, an upper radial magnetic bearing 2, a machine shell 3, a non-magnetic conductive snap ring 4, an upper magnetic conductive disc 5, a rotor yoke 6, a rotating shaft 7, a permanent magnet pole 8, an armature winding 9, a stator core 10, a lower end cover 11, a flywheel rotor 12, an axial protection bearing 13, an axial passive magnetic bearing 14, a protection gasket 15 and a lower radial magnetic bearing 16.

The structure comprises a stator tooth part 10-1, a stator yoke part 10-2, an upper moving bearing disc 14-1 of an axial passive magnetic bearing and a lower static bearing disc 14-2 of the axial passive magnetic bearing;

for convenience of describing a magnetic circuit, the permanent magnet poles are divided into permanent magnets 8-1 and adjacent permanent magnets 8-2, and stator teeth of the path are divided into stator teeth 10-11 and adjacent stator teeth 10-12.

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 novel disk type permanent magnet synchronous motor for an energy storage flywheel based on magnetic suspension support, wherein the motor is matched with a magnetic suspension bearing system which plays a supporting role in the energy storage flywheel, and the energy exchange of mechanical kinetic energy and electric energy of the energy storage flywheel is realized.

The disclosed embodiment takes an 8-pole 72-slot disc type permanent magnet synchronous motor as an example, and fig. 1 is an overall structure of an energy storage flywheel based on magnetic suspension support, which is provided by the invention and comprises an upper end cover 1, an upper radial magnetic bearing 2, a machine shell 3, a non-magnetic retaining ring 4, an upper magnetic disk 5, a rotor yoke 6, a rotating shaft 7, a permanent magnet pole 8, an armature winding 9, a stator core 10, a lower end cover 11, a flywheel rotor 12, an axial protection bearing 13, an axial passive magnetic bearing 14, a protection gasket 15 and a lower radial magnetic bearing 16.

Fig. 2 is a main body portion of a disc-type permanent magnet synchronous motor according to the invention, and referring to fig. 2, with reference to fig. 5, 6, 7 and 8, the disc-type permanent magnet synchronous motor for an energy storage flywheel based on magnetic levitation support in the present embodiment will be described in detail.

The motor body is divided into three parts of a stator core, an armature winding and a rotor disc, wherein the stator core 10 comprises two parts of a stator tooth 10-1 and a stator yoke 10-2 and is formed by combining soft magnetic composite SMC (sheet molding compound) molded core blocks; the armature winding 9 is a short-moment distributed winding and is wound on the stator teeth 10-1, and the coils are arranged in a double-layer mode along the axial direction.

The armature winding 9 is wound on the stator teeth, the axial height is short, and the axial size of the motor is greatly compressed.

The motor and the generator are integrated, so that the reciprocal operation of electric/power generation can be realized, and the motor can work in two states of electric and power generation.

The rotor disc is composed of a rotor yoke disc 6 and eight permanent magnets 8 which are arranged in a staggered mode along the circumferential direction of N poles and S poles, wherein the permanent magnets 8 are evenly embedded on the upper surface of the rotor yoke 6 according to the required number of magnetic poles, and the permanent magnets 8 are of a fan-shaped structure and are magnetized in the axial direction; in order to facilitate installation and reduce loss, each permanent magnet 8 needs to be divided into a plurality of small blocks along the axial direction and the circumferential direction in actual manufacturing, and then the small blocks are adhered together and then are axially magnetized integrally.

The structure of a stator core 10 of the embodiment of the disclosure is given by fig. 5, and the structure diagram of a permanent magnet 8 is shown in fig. 6, wherein fig. 6-a is a structure diagram of a single permanent magnet, and fig. 6-b is a structure diagram of an integral permanent magnet; the structure of the armature winding 9 of the disclosed embodiment is given by fig. 8, wherein fig. 8-a is a single coil structure diagram, and fig. 8-b is an integral armature winding structure diagram.

In the embodiment of the invention, the assembly schematic diagram of the flywheel energy storage motor is shown in fig. 3, the motor is arranged between the flywheel casing 3 and the upper radial magnetic bearing 2, the upper end stator disc 10 of the motor is arranged between the periphery of the upper radial magnetic bearing 2 and the flywheel casing, the space between the radial magnetic bearing and the flywheel casing is effectively utilized, the axial height of the motor is greatly reduced, the supporting effect of the radial magnetic bearing on the motor is better, meanwhile, the flywheel rotor 12 is used as a magnetic conducting yoke disc of a lower end rotor disc, and the permanent magnet 8 is embedded on the flywheel rotor. The maximum outer diameter of the outer end part of the winding 9 of the motor stator disc is smaller than the inner diameter of the stator shell, and the inner diameter of the inner end part of the winding 9 of the motor stator disc is larger than the outer diameter of the magnetic bearing; the structural relationship between the rotor permanent magnet 8 and the rotor yoke disc 6 is shown in fig. 7, the outer diameter of the rotor yoke disc 6 is slightly larger than the outer diameter of the permanent magnet 8, the end face of the rotor 6 in the winding end range is required to be lower than the upper surface of the permanent magnet 8 but not more than half of the axial thickness of the permanent magnet 8, the end face of the rotor 6 outside the winding end range, namely the permanent magnet 8, is flush with the upper surface of the permanent magnet 8, and the motor stator disc and the rotor disc keep coaxiality.

The stator assembly is schematically shown in fig. 9, a non-magnetic snap ring 4 is arranged at the upper end of a stator core plate 10, the non-magnetic snap ring 4 and a stator core 10 are integrated, so that the axial height of the stator of the compensation motor is the same as the height of the radial magnetic bearing, and simultaneously, the leakage flux existing in the stator core is prevented from flowing into the upper end magnetic conduction disc 5, in addition, the stator disc 10 of the motor and the stator of the radial magnetic bearing 2 are also assembled together through the upper end magnetic conduction disc 5, wherein the outer diameter and the inner diameter of the non-magnetic conductive ring 4 are slightly larger than the inner diameter and the outer diameter of the stator core 10, the retaining ring 4 is tightly buckled at the top of the motor stator core 10 through a bolt, the inner periphery of the upper end magnetic conductive disc 5 is arranged on the radial magnetic bearing shell, the outer periphery is fixed on the inner wall of the flywheel shell 3, the disc type motor is connected with the flywheel casing 3 and the radial magnetic bearing 2 through the magnetic conduction disc 5, so that the assembly is convenient to disassemble, assemble and fix, and effective bearing of the bearing is guaranteed. In addition, during assembly, an adjusting cushion block 15 needs to be additionally arranged at the joint of the magnetic conduction disc 5 and the flywheel casing 3 to ensure that the air gap of the motor is unchanged, the radial magnetic bearing 2 and the flywheel casing 3 are in interference fit with the magnetic conduction disc 5, and meanwhile, for reducing the temperature rise of the stator, the upper end of the magnetic conduction disc is grooved and water pipes are laid for water cooling.

The present material of the motor rotor yoke disc is magnetic-conductive flywheel steel, the fan-shaped permanent magnet is made of rare earth material with excellent performance, and the stator core is formed by combining soft magnetic composite material SMC mould pressing core blocks.

In the embodiment of the invention, the motor is arranged between the flywheel casing and the radial magnetic bearing, the stator disc at the upper end of the motor is arranged between the periphery of the radial magnetic bearing at the upper end and the flywheel casing, the flywheel rotor is used as the magnetic conducting yoke disc of the rotor disc at the lower end, and the permanent magnet is embedded on the upper end surface of the flywheel rotor. The maximum outer diameter of the outer end part of the winding of the motor stator disc is smaller than the inner diameter of the stator casing, and the inner diameter of the inner end part of the winding of the motor stator disc is larger than the outer diameter of the magnetic bearing.

In the embodiment of the invention, the attraction force of the upper end stator disc 10 of the disc type permanent magnet synchronous motor to the rotor disc 6 needs the axial repulsive force of the lower axial passive magnetic bearing 14 which is lower than 1/2 times, so the axial surface of the upper end of the flywheel rotor 12 needs to be additionally provided with the axial protective bearing 13 to ensure the air gap of the motor; the axial passive magnetic bearing 14 is arranged below the flywheel rotor 12 and comprises two bearing discs, an upper movable bearing 14-1 is fixed on the lower surface of the flywheel rotor 12, and a lower static bearing disc 14-2 is fixed with the lower end cover 11.

In the embodiment of the invention, the motor stator disc and the radial magnetic bearing stator are assembled together through the upper end magnetic conduction disc, and an adjusting cushion block and an axial protection bearing are additionally arranged at the joint of the magnetic conduction disc and the flywheel casing to ensure the size of an air gap during assembly.

The motor and the generator are integrated, when the flywheel is used as the motor, the flywheel rotates at high speed to convert electric energy into mechanical kinetic energy for storage, and when the flywheel is used as the generator to run, the flywheel decelerates to release energy for load use; the motor has the advantages that the whole structure is compact, the volume and the weight are greatly reduced, the types of the motor for the energy storage flywheel and the application occasions of the disc type permanent magnet synchronous motor are expanded, the axial length of the motor is shortened, the inner space of the flywheel is saved, the motor is very suitable for being applied to high-capacity flywheel energy storage, and the development prospect is great.

Example two

The purpose of this embodiment is to provide the installation step of disk PMSM and energy storage flywheel: firstly, the integral flywheel rotor 12 is installed in place, the axial position of the permanent magnet 8 on the upper end face of the flywheel rotor is measured, so that the installation position of the stator disc 10 is determined, the axial gap between the motor stator disc 10 and the rotor disc is sequentially ensured, in addition, the integral rotor is required to be axially positioned by additionally arranging a position sensor, and the fact that the motor rotor disc is not attached to the stator disc 10 under the suction action of the stator disc 10 is ensured.

EXAMPLE III

The purpose of this embodiment is to provide a working method of a disc-type permanent magnet synchronous motor, including:

the air gap mentioned in the main magnetic circuit is the air gap a between the stator core 10 and the rotor disc, and the main magnetic circuit of the motor is specifically shown in the added figure 11, and the air gap in the main magnetic circuit is marked;

to illustrate the magnetic circuit of the motor by taking fig. 11 as an example, the permanent magnetic flux sequentially passes through the rotor disc permanent magnet 8-1 → the air gap a → the stator tooth 10-11 → the stator yoke 10-2 → the adjacent stator tooth 10-12 → the air gap a → the adjacent rotor disc permanent magnet 8-2 → the rotor yoke disc 6 → finally the original rotor disc permanent magnet 8-1 to form a closed loop;

the polarities of two adjacent permanent magnets in the circumferential direction are opposite, when a rotor 12 of a prime motor rotates, a permanent magnet pole 8 serves as the rotor to generate a synchronous rotating magnetic field, magnetic flux inside a stator core 10 is alternated, a three-phase stator winding 9 wound on the stator core 10 induces induced electromotive force through armature reaction under the action of the rotating magnetic field, then three-phase symmetrical current is generated in the winding 9, 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 9 is 120 degrees each other in spatial position, so three-phase stator current produces the 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 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. 10 (only the wiring mode of the a-phase winding is listed, B, C phases are the same, and three phases are mutually different by 120 °), the stator winding 9 is a short-moment distributed winding, and is arranged in double layers along the radial direction, a central line is led out, the axial height of the winding is short, and the axial length of the motor is greatly reduced.

Compared with a cup type stator core, the disc type stator has the advantages that the stator core and the rotor are arranged from top to bottom, the installation is convenient, the space inside and outside the disc diameter is large, the winding end part is convenient to place, the difficulty in fixing the winding does not exist, the axial height is small, the passive magnetic bearing with the unilateral magnetic pulling force and the large bearing capacity is required to bear, and the iron loss exists at the same time. Application scenarios the disc motor is generally suitable for high-speed, high-capacity flywheels and is supported by high-bearing-capacity bearings.

Therefore, compared with the traditional permanent magnet motor for the energy storage flywheel, the disc type permanent magnet synchronous motor for the energy storage flywheel based on the magnetic suspension support has the remarkable advantages of high power density and high efficiency, is expected to be obtained by a flywheel energy storage system, and has a certain application prospect in future high-speed flywheel energy storage systems. In addition, compared with a dual-rotor or dual-stator disc type permanent magnet synchronous motor commonly used in a flywheel energy storage system, the disc type permanent magnet synchronous motor based on the magnetic suspension support is more compact in structure and simpler to assemble, the axial length of the motor is greatly reduced, the utilization degree of the internal space of the flywheel is improved, and meanwhile, the problem of unilateral magnetic tension of the conventional single-stator single-rotor disc type permanent magnet synchronous motor is solved by additionally arranging an axial passive magnetic bearing, an axial protective bearing and a radial magnetic bearing.

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. Disc PMSM, characterized by includes:

an upper stator disk and a lower rotor disk;

the rotor disc is composed of a rotor yoke disc and permanent magnets which are arranged in a staggered mode along the circumferential direction of N poles and S poles, wherein the number of magnetic poles of the permanent magnets is uniformly embedded on the upper surface of the rotor yoke;

the outer diameter of the rotor yoke disc is slightly larger than that of the permanent magnet, the rotor end face inside the winding end range is lower than the upper surface of the permanent magnet but not more than half of the axial thickness of the permanent magnet, the rotor end face outside the winding end range, namely the outer side of the permanent magnet, is flush with the upper surface of the permanent magnet, the coaxiality of the stator disc and the rotor disc of the motor is kept, and an air gap between the stator disc and the rotor disc is ensured through a size chain.

2. The disc type permanent magnet synchronous motor according to claim 1, wherein the stator disc and the rotor disc are vertically arranged in an axial direction;

3. A disc-type permanent magnet synchronous machine according to claim 1, wherein the permanent magnets of the rotor disc are manufactured by dividing each permanent magnet pole into a plurality of small pieces in a radial direction and a circumferential direction for easy installation.

4. The disc type permanent magnet synchronous motor according to claim 1, wherein the rotor yoke disc is made of magnetically conductive flywheel steel, the segment permanent magnets are made of rare earth material, and the stator core is assembled by soft magnetic composite SMC molded core blocks.

5. An energy storage flywheel, comprising a disc-type permanent magnet synchronous motor according to any one of claims 1 to 4, wherein a non-magnetic conductive ring is arranged at the upper end of a stator core of the synchronous motor, the non-magnetic conductive ring is combined with the stator core, and a stator disc and a radial magnetic bearing stator are assembled together through a magnetic conductive disc at the upper end.

6. An energy storage flywheel according to claim 5 wherein the outer and inner diameters of the non-magnetic ring are slightly larger than the inner and outer diameters of the stator core, and the non-magnetic ring is fastened to the top of the stator core by bolts in an interference fit.

7. An energy storage flywheel as claimed in claim 5 wherein the upper magnetically conductive disc is disposed on the inner periphery of the radial magnetic bearing housing and the outer periphery is fixed to the inner wall of the flywheel housing, the disc motor is connected to the flywheel housing and the radial magnetic bearing via the magnetically conductive disc, and the connection position is sealed by rubber sealing rings, and during assembly, an adjusting pad block is additionally mounted at the connection position between the magnetically conductive disc and the flywheel housing to ensure that the air gap of the motor is not changed.

8. An energy storage flywheel as claimed in claim 7 wherein the mechanical engagement between the radial magnetic bearing and the flywheel casing and the magnetically conductive disc is interference fit, and the magnetically conductive disc is grooved and water-cooled by laying water pipes.

9. An energy storage flywheel according to claim 5 wherein the motor is disposed between the flywheel housing and the radial magnetic bearing, the upper stator disc of the motor is disposed between the outer periphery of the upper radial magnetic bearing and the flywheel housing, the flywheel rotor is used as a magnetic yoke disc of the lower rotor disc, the permanent magnets are embedded on the upper end face of the flywheel rotor, the maximum outer diameter of the outer end portion of the winding of the motor stator disc is smaller than the inner diameter of the stator housing, and the inner diameter of the inner end portion of the winding of the motor stator disc is larger than the outer diameter of the magnetic bearing.

10. An energy storage flywheel according to claim 9 wherein the attractive force of the upper stator disc of the motor to the rotor disc requires less than 1/2 times the axial repulsive force of the axial passive magnetic bearing, and an axial protective bearing is added to the upper axial surface of the flywheel rotor to ensure the motor air gap.

11. An energy storing flywheel as claimed in claim 5 wherein the axially passive magnetic bearing in the energy storing flywheel, located below the flywheel rotor, comprises two bearing discs, the upper movable bearing being fixed to the lower surface of the flywheel rotor, the lower stationary bearing disc being fixed to the end cap with a suitable air gap between the bearing discs.

12. The method for installing the energy storage flywheel is characterized by comprising the following steps:

an energy storage flywheel according to any of claims 5 to 11 wherein the integral flywheel rotor is mounted in position by measuring the axial position of the permanent magnets on the upper end face of the flywheel rotor to determine the mounting position of the stator disc, which in turn ensures the axial clearance between the stator disc and the rotor disc of the motor, and in addition, the integral rotor is axially positioned to ensure that the rotor disc of the motor does not stick to the stator disc under the suction of the stator disc.

13. A method for operating a disc-type permanent magnet synchronous motor, according to any one of claims 1 to 4, comprising: