Flywheel energy storage device with reduced power consumption

Abstract

The utility model relates to the flywheel energy storage technical field, and disclose a kind of flywheel energy storage device of reducing power consumption, including upper motor and energy storage mechanism, the upper motor and energy storage mechanism are communicated to form vacuum cavity, the rotating joint of the shaft that the bottom end extends to the inside of energy storage mechanism is connected in the inside of the upper motor, the inside fixedly connected with the sealing cover of the bottom and energy storage mechanism fixed connection of the upper motor, the sealing cover is sleeved in the outside of shaft, the upper motor includes upper casing;This flywheel energy storage device of reducing power consumption can solve the problem of motor temperature rise caused by low heat dissipation coefficient of excitation winding and large rotor eddy current loss, the problem of high self-discharge rate caused by permanent magnet suspension flywheel rotor, the problem of high manufacturing cost caused by winding potting, improve the stability, security in the process of flywheel energy storage system use, reduce flywheel energy storage system cost.

Description

Technical Field

[0001] This utility model relates to the field of flywheel energy storage technology, specifically a flywheel energy storage device that can reduce power consumption. Background Technology

[0002] The flywheel energy storage motor is the core component of the system's energy conversion, and its performance directly affects the performance of the entire flywheel energy storage system. In energy storage devices with flywheels powered by permanent magnet motors, the rotor linear velocity cannot be too high during high-speed operation due to the rotor's mechanical strength. Permanent magnets are highly sensitive to temperature rise; during prolonged operation, heat accumulation in the permanent magnets, coupled with poor heat dissipation in the vacuum chamber, can easily lead to irreversible demagnetization of the permanent magnets, resulting in a decrease in motor power. Furthermore, the magnetic field generated by the permanent magnets cannot be eliminated during the flywheel energy storage system's no-load standby period, especially under long-term standby conditions, inevitably leading to no-load stator iron losses and rotor eddy current losses, resulting in wasted mechanical energy in the flywheel rotor.

[0003] For example, in a stator hybrid excitation flywheel energy storage motor disclosed in Chinese patent CN112398269A, through magnetic circuit innovation, the magnetic field generated by the permanent magnet ring is mainly used to provide axial upward electromagnetic force to the flywheel rotor during energy storage, resulting in low bearing load and losses. During charging and discharging, the excitation winding and the permanent magnet ring are hybrid excited. Through the cooperation of the excitation winding, the electromagnetic force on the flywheel rotor remains constant, achieving the same effect of unloading the bearings. However, because the upper and lower end covers are made of ferromagnetic materials, the magnetic circuit of the excitation winding and the magnetic circuit of the permanent magnet ring are coupled. If the current of the excitation winding is unstable, the levitation force of the flywheel rotor is also unstable. Since the rotor of this motor also functions as a flywheel, there is coupling between the motor's power and the stored energy. This flywheel energy storage motor uses the levitation force generated by the permanent magnet to levitate the flywheel rotor, and the permanent magnet is located above the rotor. However, the rotor of the induction motor has large eddy current losses and is not easy to dissipate heat in a vacuum environment. Therefore, the rotor will radiate its temperature to the permanent magnet, causing the levitation force generated by the permanent magnet to fluctuate continuously, which is not conducive to the safe and stable operation of the flywheel energy storage system. In addition, during standby operation, the permanent magnet field will generate iron loss in the motor, which will continuously consume the energy stored in the flywheel, thereby reducing the overall energy conversion efficiency of the flywheel energy storage system.

[0004] For example, in a stator electrically excited flywheel energy storage motor disclosed in Chinese patent CN113300532A, the invention reduces the bearing load by cooperating with the permanent magnet unloading bearing and the induction motor. Furthermore, through magnetic circuit innovation and the use of non-ferromagnetic materials for the upper and lower end covers, the magnetic coupling between the permanent magnet unloading bearing and the motor is very small, and changes in the motor's excitation current do not affect the rotor's levitation force. During motor operation, the load fluctuation at the bearing is small, resulting in high stability and significantly extending the bearing's service life. However, during motor charging and discharging, the excitation winding generates significant DC copper losses, and the circular winding is not easy to dissipate heat, leading to high temperature rises in various motor components. During standby operation, the permanent magnet magnetic field generates iron losses in the motor, which continuously consumes the energy stored in the flywheel, thereby reducing the overall energy conversion efficiency of the flywheel energy storage system. In addition, this patent also suffers from the problems of coupling between the energy storage motor power and the stored energy, and large fluctuations in the levitation force of the permanent magnet unloading bearing, as found in Chinese patent CN112398269A. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a flywheel energy storage device that can reduce power consumption. Its purpose is to reduce the temperature rise of various components of the flywheel energy storage device, reduce the self-discharge rate of the flywheel energy storage motor, and increase the energy storage capacity of the flywheel energy storage device. This improves the practicality, economy, and safety of the flywheel energy storage system, thereby solving the problems of high motor temperature caused by low excitation winding heat dissipation coefficient and high rotor eddy current loss, high self-discharge rate caused by permanent magnet levitation flywheel rotor, and high manufacturing cost caused by winding potting in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a flywheel energy storage device that can reduce power consumption, comprising an upper motor and an energy storage mechanism, wherein the upper motor and the energy storage mechanism are connected to form a vacuum cavity, wherein a rotating shaft extending from the bottom end into the energy storage mechanism is rotatably connected inside the upper motor, and a sealing cover fixedly connected to the bottom of the upper motor and fixedly connected to the energy storage mechanism is fixedly connected inside the upper motor, wherein the sealing cover is sleeved on the outside of the rotating shaft.

[0007] Preferably, the upper motor includes an upper housing, on the inner wall of which a first annular stator core and a second annular stator core are fixedly connected. Both the inner and outer sides of the first and second annular stator cores are provided with opening slots. The opening slots on the inner sides of the first and second annular stator cores are fixedly connected to armature windings. The upper motor also includes a first rotor and a second rotor, which are fixedly connected to the outside of the rotating shaft. The sealing cover is fitted over the outside of the first and second rotors.

[0008] Preferably, the energy storage mechanism includes a lower housing, the sealing cover is fixedly connected to the inner top wall of the lower housing, an electromagnetic unloading bearing is fixedly connected to the bottom of the sealing cover, the electromagnetic unloading bearing includes a magnetic core, an electromagnetic winding is fixedly connected inside the magnetic core, a flywheel located below the magnetic core is rotatably connected inside the energy storage mechanism, and the bottom of the rotating shaft is fixedly connected to the top of the flywheel.

[0009] Preferably, the top of the upper housing and the bottom of the lower housing are both fixedly connected to bearing seats, and mechanical bearings are fixedly connected inside the two bearing seats. The rotating shaft is rotatably connected to the upper motor through the upper mechanical bearing, and the flywheel is rotatably connected to the energy storage mechanism through the lower mechanical bearing.

[0010] Preferably, the sealing cover has an L-shaped cylindrical structure, and the inner top wall of the upper housing is fixedly connected with two concentric rings of bosses, forming a slot between the two concentric rings of bosses. The top of the vertical wall of the sealing cover is fixedly connected to the inside of the slot, and the horizontal surface of the sealing cover is fixedly connected between the magnetic core and the lower housing.

[0011] Preferably, both the upper and lower housings are ferromagnetic housings, both the first and second rotors are silicon steel rotors, the first annular stator core, the second annular stator core, and the magnetic core are all ferromagnetic cores, the flywheel is a ferromagnetic wheel, and the shaft is a ferromagnetic shaft.

[0012] Preferably, the first excitation winding and the second excitation winding are respectively placed in the opening slots on the outer sides of the first annular stator core and the second annular stator core.

[0013] Preferably, a third excitation winding is fixedly connected between the first annular stator core and the second annular stator core.

[0014] Compared with the prior art, this utility model provides a flywheel energy storage device that can reduce power consumption, and has the following beneficial effects:

[0015] 1. The stator electrically excited flywheel energy storage device proposed in this invention, on the one hand, places the excitation winding in the toothed structure on the outside of the stator, thereby enhancing the heat dissipation coefficient of the excitation winding and reducing the temperature rise of various components of the motor; on the other hand, the non-integrated structure of the flywheel and rotor in the rotating components allows the rotor to be made of silicon steel sheet material, which can effectively reduce the eddy current loss of the rotor, thereby reducing the temperature rise of the rotor.

[0016] 2. This invention separates the excitation magnetic circuit and the levitation magnetic circuit, and uses an electromagnetic unloading bearing to levitate the flywheel and energy storage motor. This ensures that the excitation and levitation magnetic circuits do not interfere with each other, and reduces the impact of the internal temperature of the flywheel energy storage device on the magnetic bearing. This significantly reduces fluctuations in levitation force and effectively improves the safety and reliability of the flywheel energy storage device. Furthermore, the self-discharge rate of the flywheel energy storage system is extremely low after the excitation current is cut off during standby operation, effectively improving the overall energy conversion efficiency of the flywheel energy storage system.

[0017] 3. By using a sealing cover to seal the excitation winding and armature winding, the present invention eliminates the need for potting with epoxy resin materials, which can effectively reduce the cost of motor manufacturing.

[0018] 4. By setting the upper and lower housings to be ferromagnetic housings, the rigidity of the motor can be enhanced, thereby effectively reducing mechanical vibration during motor operation. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the connection structure in Embodiment 1 of this utility model;

[0021] Figure 3 This is a schematic diagram of the first rotor structure of this utility model;

[0022] Figure 4 This is a schematic diagram of the connection structure between the annular stator core and the excitation winding in Embodiment 1 of this utility model;

[0023] Figure 5 This is a schematic diagram of the sealing cover structure of this utility model;

[0024] Figure 6 This is a schematic diagram of the connection structure in Embodiment 2 of this utility model;

[0025] Figure 7 This diagram shows the magnetic flux path of the main magnetic circuit and the magnetic flux path of the levitation magnetic circuit of this invention.

[0026] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of this utility model.

[0027] In the diagram: 1. Upper motor; 101. Upper housing; 102. First annular stator core; 103. Second annular stator core; 104. Armature winding; 105. First excitation winding; 106. Second excitation winding; 107. Third excitation winding; 11. First rotor; 12. Second rotor; 2. Energy storage mechanism; 201. Lower housing; 202. Flywheel; 3. Shaft; 4. Sealing cover; 5. Electromagnetic unloading bearing; 501. Magnetic core; 502. Electromagnetic winding; 6. Bearing housing; 7. Mechanical bearing. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1, please refer to Figure 1-5A flywheel energy storage device with reduced power consumption includes an upper motor 1 and an energy storage mechanism 2. The upper motor 1 and the energy storage mechanism 2 are connected to form a vacuum cavity. A rotating shaft 3, with its bottom end extending into the energy storage mechanism 2, is rotatably connected inside the upper motor 1. The rotating shaft 3 is a 40Cr alloy steel shaft or a Q235 alloy steel shaft. A sealing cover 4, with its bottom fixedly connected to the energy storage mechanism 2, is fixedly fitted outside the rotating shaft 3. The upper motor 1 includes an upper housing 101. A sealed space is formed between the sealing cover 4 and the upper housing 101. A first annular stator core 102 and a second annular stator core 103 are fixedly connected to the inner wall of the upper housing 101. The first annular stator core 102 and the second annular stator core 103 have the same shape. The annular stator core 102 and the second annular stator core 103 are disposed between the sealing cover 4 and the upper housing 101. Opening slots are provided on both the inner and outer sides of the first annular stator core 102 and the second annular stator core 103. The opening slots on the inner side of the first annular stator core 102 and the second annular stator core 103 are fixedly connected to the armature winding 104. The opening slots on the outer side of the first annular stator core 102 and the second annular stator core 103 respectively contain the first excitation winding (105) and the second magnetic winding (106). The second magnetic winding (106) has the same shape as the first excitation winding (105). The first excitation winding 105 and the second magnetic winding 106 are connected to DC excitation current during charging and discharging, and DC excitation is stopped during energy storage and holding. The upper motor 1 also includes a first rotor 11 and a second rotor 12. The first rotor 11 and the second rotor 12 have the same shape. Both the first rotor 11 and the second rotor 12 are silicon steel rotors. The first rotor 11 and the second rotor 12 are fixedly connected to the outside of the rotating shaft 3 from top to bottom. The sealing cover 4 is sleeved on the outside of the first rotor 11 and the second rotor 12. The energy storage mechanism 2 includes a lower housing 201. Both the upper housing 101 and the lower housing 201 are ferromagnetic housings. The sealing cover 4 is fixedly connected to the inner top wall of the lower housing 201. An electromagnetic unloading bearing 5 is fixedly connected to the bottom of the sealing cover 4. The electromagnetic unloading bearing 5 includes a magnetic core 501. The first annular stator core 102, the second annular stator core 103 and the magnetic core (5) are all silicon steel. The core and the magnetic core 501 are internally connected to an electromagnetic winding 502. The magnetic core 501 has a downward-opening groove structure. The electromagnetic winding 502 is embedded in the groove of the magnetic core 501. The energy storage mechanism 2 is internally connected to a flywheel 202 located below the magnetic core 501. The flywheel 202 is a ferromagnetic wheel. There is an air gap between the flywheel 202 and the electromagnetic unloading bearing 5. The bottom of the rotating shaft 3 is fixedly connected to the top of the flywheel 202. The sealing cover 4 has an L-shaped cylindrical structure. The inner top wall of the upper housing 101 is fixedly connected to two rings of bosses, forming a slot between the two rings of bosses. The top of the vertical wall of the sealing cover 4 is fixedly connected to the slot. The horizontal surface of the sealing cover 4 is fixedly connected between the magnetic core 501 and the lower housing 201.

[0030] In this embodiment, the excitation winding is wound in an open slot on the outside of the stator core, which can effectively increase the heat dissipation coefficient of the excitation winding and thus reduce the temperature rise of various components of the motor.

[0031] In this embodiment, the armature winding 104, the first excitation winding (105), and the second magnetic winding (106) are sealed by a sealing cover instead of potting, which can effectively reduce the cost of motor manufacturing.

[0032] Example 2, please refer to Figure 6-7 This embodiment is a further optimization based on Embodiment 1. The parts that are the same as those described above will not be repeated here. Figure 1-5 As shown, in order to better realize the present invention, the following configuration is adopted: the top of the upper housing 101 and the bottom of the lower housing 201 are both fixedly connected to bearing seats 6, and mechanical bearings 7 are fixedly connected inside the two bearing seats 6. The rotating shaft 3 is rotatably connected to the upper motor 1 through the upper mechanical bearing 7, and the flywheel 202 is rotatably connected to the energy storage mechanism 2 through the lower mechanical bearing 7.

[0033] In this embodiment, during charging and discharging, the main magnetic flux path of the motor and the magnetic flux path of the levitation magnetic circuit are as follows: Figure 6 and Figure 7 As shown. The main magnetic flux path is: first rotor → main air gap → first stator → upper housing → second stator → air gap → second rotor → shaft → first rotor; the magnetic flux path of the levitation magnetic circuit is: magnetic core of the electromagnetic unloading bearing → axial air gap → flywheel → axial air gap → magnetic core of the electromagnetic unloading bearing. The magnetic flux acts on the lower surface of the magnetic core, providing an axially upward electromagnetic force to the flywheel, partially or completely offsetting the gravity of the flywheel 202, thereby reducing the load borne by the mechanical bearing 7. In addition, since the excitation magnetic circuit of the energy storage motor and the levitation magnetic circuit of the electromagnetic unloading bearing do not affect each other, the stability of the levitation force is ensured.

[0034] Furthermore, when the excitation winding is not energized, there is no magnetic flux in the first annular stator core 102, the second annular stator core 103, the flywheel 202, and the magnetic core 501. Therefore, the motor has no no-load standby loss, thereby improving the energy conversion efficiency of the motor.

[0035] Example 3, please refer to Figure 8 A third excitation winding 107 is fixedly connected between the first annular stator core 102 and the second annular stator core 103. The third excitation winding 107 has a circular annular structure.

[0036] It is understandable that in the above embodiments, the motor has no electromagnetic loss during energy storage standby and has a high energy conversion rate. The flywheel 202 is subjected to a stable levitation force throughout the entire charging and discharging process, reducing the load and loss on the mechanical bearing 7 and extending its service life. The excitation winding has a high heat dissipation coefficient, and the first rotor 11 and the second rotor 12 are made of silicon steel, which can effectively reduce the temperature rise of various components of the motor. The overall structure of the motor is simple, compact, and low in cost, with good rotor dynamic characteristics and easy processing, making it very suitable for flywheel energy storage applications.

[0037] In summary, this flywheel energy storage device, which reduces power consumption, can solve the problems of high motor temperature caused by low excitation winding heat dissipation coefficient and high rotor eddy current loss, high self-discharge rate caused by permanent magnet levitation flywheel rotor, and high manufacturing cost caused by winding potting. It improves the stability and safety of the flywheel energy storage system during use and reduces the cost of the flywheel energy storage system.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flywheel energy storage device with reduced power consumption, comprising an upper motor (1) and an energy storage mechanism (2), wherein the upper motor (1) and the energy storage mechanism (2) are connected to form a vacuum cavity, characterized in that: The upper motor (1) is rotatably connected to a rotating shaft (3) whose bottom end extends into the energy storage mechanism (2). The upper motor (1) is fixedly connected to a sealing cover (4) whose bottom end is fixedly connected to the energy storage mechanism (2). The sealing cover (4) is sleeved on the outside of the rotating shaft (3).

2. The flywheel energy storage device with reduced power consumption according to claim 1, characterized in that: The upper motor (1) includes an upper housing (101), on the inner wall of which a first annular stator core (102) and a second annular stator core (103) are fixedly connected. The inner and outer sides of the first annular stator core (102) and the second annular stator core (103) are provided with opening slots. The opening slots on the inner side of the first annular stator core (102) and the second annular stator core (103) are fixedly connected to the armature winding (104). The upper motor (1) also includes a first rotor (11) and a second rotor (12), which are fixedly connected to the outside of the rotating shaft (3). The sealing cover (4) is sleeved on the outside of the first rotor (11) and the second rotor (12).

3. The flywheel energy storage device with reduced power consumption according to claim 2, characterized in that: The energy storage mechanism (2) includes a lower housing (201), the sealing cover (4) is fixedly connected to the inner top wall of the lower housing (201), the bottom of the sealing cover (4) is fixedly connected to an electromagnetic unloading bearing (5), the electromagnetic unloading bearing (5) includes a magnetic core (501), the inside of the magnetic core (501) is fixedly connected to an electromagnetic winding (502), the inside of the energy storage mechanism (2) is rotatably connected to a flywheel (202) located below the magnetic core (501), and the bottom of the rotating shaft (3) is fixedly connected to the top of the flywheel (202).

4. The flywheel energy storage device with reduced power consumption according to claim 3, characterized in that: The top of the upper housing (101) and the bottom of the lower housing (201) are both fixedly connected to bearing seats (6), and mechanical bearings (7) are fixedly connected inside the two bearing seats (6). The rotating shaft (3) is rotatably connected to the upper motor (1) through the upper mechanical bearing (7), and the flywheel (202) is rotatably connected to the energy storage mechanism (2) through the lower mechanical bearing (7).

5. A flywheel energy storage device with reduced power consumption according to claim 3, characterized in that: The sealing cover (4) has an L-shaped cylindrical structure. The inner top wall of the upper housing (101) is fixedly connected with two inner and outer rings of bosses, and a slot is formed between the two rings of bosses. The top of the vertical wall of the sealing cover (4) is fixedly connected to the inside of the slot. The horizontal surface of the sealing cover (4) is fixedly connected between the magnetic core (501) and the lower housing (201).

6. The flywheel energy storage device with reduced power consumption according to claim 3, characterized in that: The upper housing (101) and the lower housing (201) are both ferromagnetic housings, the first rotor (11) and the second rotor (12) are both silicon steel rotors, the first annular stator core (102), the second annular stator core (103) and the magnetic core (501) are all ferromagnetic cores, the flywheel (202) is a ferromagnetic wheel, and the rotating shaft (3) is a ferromagnetic shaft.

7. A flywheel energy storage device with reduced power consumption according to claim 2, characterized in that: The first excitation winding (105) and the second excitation winding (106) are respectively placed in the opening slots on the outside of the first annular stator core (102) and the second annular stator core (103).

8. A flywheel energy storage device with reduced power consumption according to claim 2, characterized in that: A third excitation winding (107) is fixedly connected between the first annular stator core (102) and the second annular stator core (103).

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