An electrically powered flywheel energy storage device having separate motor and generator

Abstract

The utility model relates to the technical field of flywheel energy storage, and disclose a kind of flywheel energy storage device of electric power generation separation, including lower casing, the top of the lower casing is fixedly connected with upper casing, the top of the lower casing and the bottom of upper casing are all provided with through-hole;The flywheel energy storage device of electric power generation separation, solve the armature winding used in the electric state and the power generation state in the prior art is same, i. e. motor stator armature winding, bidirectional energy transfer is carried out;The energy storage capacity of flywheel energy storage device mainly depends on the size and rotational speed of flywheel rotor, and its charge-discharge power depends on the power of motor, if the power of motor cannot be improved due to volume, cost and other factors, it directly limits the charge-discharge power of flywheel energy storage device this important index, and also cannot play its important advantage well in some application scenarios requiring instantaneous high-power discharge.

Description

Technical Field

[0001] This utility model relates to the field of flywheel energy storage technology, specifically a flywheel energy storage device that separates electric power generation from electric power generation. Background Technology

[0002] Flywheel energy storage devices are characterized by high power density, high charging and discharging frequency, fast operating response, and environmental friendliness. They are a new type of green energy and have been applied in fields such as rail transit, power grid frequency regulation, new energy power generation, and uninterruptible power supplies, showing good development prospects.

[0003] Flywheel energy storage devices operate in two states: motoring and generating. In motoring mode, the motor drives the flywheel rotor, utilizing the flywheel's high inertia and increasing rotational speed to convert electrical energy into mechanical energy for storage. In generating mode, the flywheel rotor decelerates and drives the motor rotor to generate electricity. Typically, both states use the same armature winding—the stator armature winding of the motor—for bidirectional energy transfer. The energy stored in a flywheel energy storage device primarily depends on the size and rotational speed of the flywheel rotor, while its charging and discharging power depends on the motor's power. If the motor power cannot be increased due to factors such as size and cost, it directly limits the crucial charging and discharging power of the flywheel energy storage device, hindering its ability to fully leverage its advantages in applications requiring instantaneous high-power discharge. Utility Model Content

[0004] To address the shortcomings and improvement needs of existing technologies, this patent provides a flywheel energy storage device that separates electric motor power generation from the transmission channel of the flywheel energy storage motor. This separates the electric motor power generation from the transmission channel of the generator power, increases the diversity of energy channel selection for charging and discharging, reduces the upper limit of heat loss in a single energy channel, indirectly increases the upper limit of operating power, and enables the control system to select energy channels with different charging and discharging powers according to different operating conditions and motor states.

[0005] The structure is designed to allow for free combination of motors with different power ratings and flywheels with different energy storage capacities. The mechanical structure is standardized for easy and quick installation and disassembly.

[0006] To achieve the aforementioned goal of separating the electric and power generation energy transmission channels of the flywheel energy storage motor, increasing the diversity of energy channel selection for charging and discharging, reducing the upper limit of heat generation and loss of a single energy channel, indirectly increasing the upper limit of operating power, and enabling the control system to select energy channels with different charging and discharging powers according to different operating conditions and motor states, this utility model provides the following technical solution: A flywheel energy storage device with electric and power generation separation, comprising a lower housing, an upper housing fixedly connected to the top of the lower housing, and through holes provided at the top of the lower housing and the bottom of the upper housing, characterized in that: a first stator core is provided inside the lower housing, the first stator core is divided into upper and lower sections, both of which are annular structures, and the upper and lower sections of the first stator core are... A ring-shaped excitation winding and a first armature winding are sequentially embedded between the stator cores from the outside to the inside along the axial direction. Both the upper and lower sections of the first stator core are fixedly connected to the inner wall of the lower housing. A flywheel rotor, which is placed inside the ring of the first stator core, is rotatably connected inside the lower housing. The flywheel rotor is a ferromagnetic rotor. A rotor core is rotatably connected inside the upper housing. The rotor core is fixedly connected to the flywheel rotor via a rotating shaft. A first radial mechanical bearing is fixedly connected to the inner bottom wall of the lower housing. A magnetic bearing is fixedly connected to the inner top wall of the lower housing. The lower housing is rotatably connected to the flywheel rotor via the first radial mechanical bearing. A second radial mechanical bearing is fixedly connected to the top of the upper housing. The upper housing is rotatably connected to the rotating shaft via the second radial mechanical bearing.

[0007] Preferably, a second stator core and a second armature winding are fixedly connected inside the upper housing. The second stator core is fixedly connected to the upper housing, and the second armature winding is wound around the outside of the second stator core. The rotor core is placed inside the second stator core and is fixedly connected to the rotating shaft.

[0008] Preferably, the magnetic bearing includes a ferromagnetic ring and a bearing excitation winding. The top of the ferromagnetic ring is fixedly connected to the lower housing. A magnetic shielding material is provided between the ferromagnetic ring and the inner top wall of the lower housing. The ferromagnetic ring has a downward-opening groove structure. The bearing excitation winding is embedded inside the ferromagnetic ring. The flywheel rotor is a ferromagnetic rotor, and the flywheel rotor and the magnetic bearing are critically attracted. The ratio of the outer diameter D1 of the ferromagnetic ring to the outer diameter D2 of the flywheel rotor is D1 = 0.8-0.9D2. The ratio of the inner diameter D3 of the ferromagnetic ring to the outer diameter D2 of the flywheel rotor is the difference D3 = 0.5-0.6D2. The ratio of the outer diameter D1 of the ferromagnetic ring to the outer diameter D4 of the second stator core is D1 = 10MM-20MM+D4. The area of ​​the ferromagnetic ring is less than or equal to the area of ​​the magnetic shielding material.

[0009] Preferably, the lower housing is connected to the upper housing via a stop, and the interiors of the lower housing and the upper housing form a vacuum cavity.

[0010] Preferably, a boss is fixedly connected to the bottom of the rotating shaft, and a slot adapted to the boss is provided on the top of the flywheel rotor. The rotating shaft and the flywheel rotor are threadedly connected through the boss and the slot.

[0011] Preferably, both the first armature winding and the second armature winding are provided with wiring devices and electrically connected to an external power source, and the first armature winding is a three-phase AC winding.

[0012] Preferably, the annular surface of the flywheel rotor is provided with a number of regular arc grooves, the number of which is a multiple of the number of rotor pole pairs.

[0013] Compared with the prior art, this utility model provides a flywheel energy storage device that separates electric power generation from electric motor power generation, which has the following beneficial effects:

[0014] 1. This application adopts a flywheel energy storage device with separate electric and power generation energy transmission channels. The flywheel energy storage control system can flexibly select the energy channel for charging and discharging, increasing the application range of the device and improving the compatibility and stability of the flywheel energy storage system.

[0015] 2. This application uses two sets of armature windings with different power to form an energy channel that separates motoring and power generation, reducing armature losses and heat generation, indirectly improving the power and efficiency of the flywheel energy storage device, and extending the device's service life.

[0016] 3. This application uses magnetic bearings to offset the weight of the flywheel rotor, reduce the axial load on the mechanical bearings, and adjust the excitation current according to real-time operating conditions to ensure that the magnetic force of the magnetic bearings remains unchanged, thereby improving the reliability of the system.

[0017] 4. This application can combine charging devices of different power levels with discharging devices of different specifications according to different needs, simplifying the design of flywheel energy storage devices. At the same time, it adopts standard mechanical interfaces, which can realize quick disassembly and replacement, and facilitate maintenance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 This is a cross-sectional view of the structure of this utility model;

[0020] Figure 3 This is a schematic diagram of the connection structure between the flywheel rotor and the shaft of this utility model;

[0021] Figure 4 This is a schematic diagram of the internal structure of the first motor of this utility model;

[0022] Figure 5 This is a topology diagram of the system application in Embodiment 1 of this utility model;

[0023] Figure 6 This is a schematic diagram of the structure of Embodiment 2 of this utility model;

[0024] Figure 7 This is a topology diagram of the system application in Embodiment 2 of this utility model;

[0025] Figure 8 This is a topology diagram of the system application in Embodiment 3 of this utility model.

[0026] In the diagram: 1. Lower housing; 2. Upper housing; 301. First stator core; 302. Annular excitation winding; 303. First armature winding; 304. Flywheel rotor; 41. Second stator core; 42. Second armature winding; 43. Rotor core; 5. Shaft; 6. First radial mechanical bearing; 7. Magnetic bearing; 71. Ferromagnetic ring; 72. Bearing excitation winding; 8. Second radial mechanical bearing; 9. Auxiliary magnetic bearing; 91. Auxiliary ferromagnetic ring; 92. Auxiliary bearing excitation winding. Detailed Implementation

[0027] 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.

[0028] Example 1, please refer to Figure 1-5A flywheel energy storage device with electric generator separation includes a lower housing 1, an upper housing 2 fixedly connected to the top of the lower housing 1, and through holes on the top of the lower housing 1 and the bottom of the upper housing 2, which connect the lower housing 1 and the upper housing 2. The lower housing 1 and the upper housing 2 are connected by a stop joint, and a vacuum cavity is formed inside the lower housing 1 and the upper housing 2. A first stator core 301, an annular excitation winding 302, a first armature winding 303, and a flywheel rotor 304 are fixedly connected inside the lower housing 1. The first stator core 301 is divided into upper and lower sections, both of which are annular structures, and the first stator core 301 is fixedly connected to the inner wall of the lower housing 1. The upper and lower sections of the first stator core 301 are connected from the outside to the inside along the centric direction. A ring-shaped excitation winding 302 and a first armature winding 303 are sequentially embedded. A flywheel rotor 304 is placed inside the ring of the first stator core 301 and the first armature winding 303. A rotor core 43 is disposed inside the upper housing 2. The flywheel rotor 304 and the rotor core 43 are fixedly connected via a rotating shaft 5. A second stator core 41 and a second armature winding 42 are also fixedly connected inside the upper housing 2. The second stator core 41 is fixedly connected to the upper housing 2, and the second armature winding 42 is wound around the outside of the second stator core 41. The rotor core 43 is placed inside the second stator core 41 and fixedly connected to the rotating shaft 5. A first radial mechanical bearing 6 is fixedly connected to the inner bottom wall of the lower housing 1. The bottom of the flywheel rotor 304 is rotatably connected to the first... Inside the radial mechanical bearing 6, a magnetic bearing 7 is fixedly connected to the inner top wall of the lower housing 1. The flywheel rotor 304 is a ferromagnetic rotor, and the flywheel rotor 304 and the magnetic bearing 7 are critically attracted. The magnetic bearing 7 applies an attractive force to the flywheel rotor 304, causing the flywheel rotor 304 to suspend within the lower housing 1. The lower end of the flywheel rotor 304 is connected to the first radial mechanical bearing 6 in several steps, integrally forged with the flywheel rotor 304. The top of the flywheel rotor 304 is fixedly connected to the rotating shaft 5, and a boss is fixedly connected to the bottom of the rotating shaft 5. The top of the flywheel rotor 304 is provided with a slot that matches the boss. The rotating shaft 5 and the flywheel rotor 304 are threadedly connected through the boss and the slot. The rotating shaft 5 and the flywheel rotor 304 are fitted with a clearance fit on one side and an interference fit on the other side. In addition to screw holes for connection and fixation, the axial plane is also drilled with set screw holes for disassembly and assembly. Both the first armature winding 303 and the second armature winding 42 are equipped with wiring devices and electrically connected to an external power supply. The first armature winding 303 is a three-phase AC winding. The annular surface of the flywheel rotor 304 has several regular arc grooves, the number of which is a multiple of the number of rotor pole pairs. Salient pole tooth grooves are designed on the surface of the flywheel rotor 304 to form a magnetic circuit that guides stator excitation, thereby forming a magnetic field on the rotor. Silicon-free steel sheets and permanent magnets are also present. The magnetic bearing 7 includes a ferromagnetic ring 71 and a bearing excitation winding 72. The top of the ferromagnetic ring 71 is fixedly connected to the lower housing 1. A magnetic shielding material, made of 304 stainless steel, is provided between the ferromagnetic ring 71 and the inner top wall of the lower housing 1.The area of ​​the magnetic shielding material is greater than or equal to the top surface area of ​​the ferromagnetic ring 71. The ferromagnetic ring 71 has a downward-opening groove structure. The bearing excitation winding 72 is embedded inside the groove of the ferromagnetic ring 71. The ratio of the outer diameter D1 of the ferromagnetic ring 71 to the outer diameter D2 of the flywheel rotor 304 is D1 = (0.8-0.9)D2. The ratio of the inner diameter D3 of the ferromagnetic ring 71 to the outer diameter D2 of the flywheel rotor 304 is the difference D3 = (0.5-0.6)D2. The ratio of the outer diameter D1 of the ferromagnetic ring 71 to the outer diameter D4 of the second stator core 41 is D1 = (10MM-20MM) + D4. The area of ​​the ferromagnetic ring 71 is less than or equal to the area of ​​the magnetic shielding material. The magnetic bearing 7 is used to counteract the weight of the flywheel rotor 304, allowing the flywheel rotor 304 to achieve axial freedom within the lower housing 1. The suspension reduces the axial load on the mechanical bearings and allows for adjustment of the excitation current based on real-time operating conditions, ensuring the magnetic force of the magnetic bearing remains constant and improving system reliability. A second radial mechanical bearing 8 is fixedly connected to the top of the upper housing 2, and the upper housing 2 is rotatably connected to the rotating shaft 5 via the second radial mechanical bearing 8. During operation, a small-power inverter and a high-power rectifier DC-DC converter are electrically connected to the output end of the DC bus. The small-power inverter and the high-power rectifier DC-DC converter are connected in parallel. A charging circuit switch is electrically connected to the output end of the small-power inverter, and the other end of the charging circuit switch is electrically connected to the second armature winding 42. A discharge circuit switch is electrically connected to the output end of the high-power rectifier DC-DC converter, and the other end of the discharge circuit switch is electrically connected to the first armature winding 303.

[0029] During system charging, a small-power converter or inverter is used to accelerate the rotor core 43. The rotor core 43 drives the flywheel rotor 304 to rotate at an accelerated speed through the rotating shaft 5, thereby storing energy. At this time, the annular excitation winding 302 located between the upper and lower sections of the first stator core 301 is not energized, and there is no magnetic field on the flywheel rotor 304. After the second armature winding 42 has completed small-power charging, when a large-power discharge is required, the charging circuit switch can be opened first, and the discharge circuit switch can be closed at the same time. At this time, the annular excitation winding 302 located between the upper and lower sections of the first stator core is energized, and a magnetic field is generated on the flywheel rotor 304, which cuts the first armature winding 303 to generate an electromotive force, thereby performing a large-power discharge.

[0030] 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 1-5As shown, to further better realize this utility model, the following arrangement is specifically adopted: the lower end of the flywheel rotor 304 is connected to the first radial mechanical bearing 6 via a short shaft fixedly connected to the flywheel rotor 304; an auxiliary magnetic bearing 9 is fixedly connected to the inner bottom wall of the lower housing 1; the auxiliary magnetic bearing 9 includes an auxiliary ferromagnetic ring 91 and an auxiliary bearing excitation winding 92; the bottom of the auxiliary ferromagnetic ring 91 is fixedly connected to the lower housing 1; a magnetic shielding material is provided between the auxiliary ferromagnetic ring 91 and the inner top wall of the lower housing 1; the magnetic shielding material is 304 stainless steel; the area of ​​the magnetic shielding material is greater than or equal to the top surface area of ​​the auxiliary ferromagnetic ring 91; and the auxiliary ferromagnetic ring 91 has an upward-opening groove structure. The auxiliary bearing excitation winding 92 is embedded in the groove of the auxiliary ferromagnetic ring 91. The auxiliary magnetic bearing 9 generates a repulsive force on it from below the flywheel rotor 304. The magnetic bearing 7 and the auxiliary magnetic bearing 9 together counteract the weight of the flywheel rotor 304. The output end of the DC bus is electrically connected to a high-power inverter and a low-power rectifier DC-DC device. The high-power inverter and the low-power rectifier DC-DC device are connected in parallel. The output end of the high-power inverter is electrically connected to a charging circuit switch. The other end of the charging circuit switch is electrically connected to the first armature winding 303. The output end of the low-power rectifier DC-DC device is electrically connected to a discharge circuit switch. The other end of the discharge circuit switch is electrically connected to the second armature winding 42.

[0031] During system charging operation, a high-power converter or inverter is used to accelerate the flywheel rotor 304. The flywheel rotor 304 drives the rotor core 43 to rotate at an accelerated speed through the rotating shaft 5, thereby storing energy. At this time, the second armature winding 42 is not energized, and there is no magnetic field on the rotor core 43. After the first armature winding 303 has completed high-power charging, when low-power discharge is required, the charging circuit switch can be opened first, and the discharge circuit switch can be closed at the same time. At this time, the second armature winding 42 is energized, and a magnetic field is generated on the rotor core 43, which cuts the second armature winding 42 to generate an electromotive force, thereby performing low-power discharge.

[0032] Example 3, please refer to Figure 8 The output terminals of the DC bus are electrically connected to a small-power inverter and a high-power inverter, which are connected in parallel. The output terminals of the small-power inverter and the high-power inverter are electrically connected to a first charge-discharge circuit switch and a second charge-discharge circuit switch, respectively. The other ends of the first charge-discharge circuit switch and the second charge-discharge circuit switch are electrically connected to the second armature winding 42 and the first armature winding 303, respectively. The other ends of the first discharge circuit switch and the second discharge circuit switch are electrically connected to the first armature winding 303 and the second armature winding 42, respectively.

[0033] By connecting the first armature winding 303 and the second armature winding 42 to charging and discharging devices separately, high-power discharge can be performed after the first armature winding 303 and the second armature winding 42 are charged at high power, or low-power discharge can be performed after the second armature winding 42 is charged at low power, or cross-charging and discharging can be performed, thus allowing the dual energy channels to be combined more freely and flexibly.

[0034] In summary, this flywheel energy storage device with separate electric and generator energy transmission channels allows the flywheel energy storage control system to flexibly select the charging and discharging energy channels, increasing the device's application range and improving its compatibility and stability. Simultaneously, by using two sets of armature windings with different power ratings to form separate energy channels for electric and generator operation, armature losses and heat generation are reduced, indirectly improving the power and efficiency of the flywheel energy storage device and extending its service life. Furthermore, different power levels of charging devices and different specifications of discharging devices can be combined according to different needs, simplifying the design of the flywheel energy storage device. The use of standard mechanical interfaces allows for quick disassembly and replacement, facilitating maintenance. Therefore, this application achieves the goal of separating the electric and generator energy transmission channels of the flywheel energy storage motor, increasing the diversity of charging and discharging energy channel selection, reducing the upper limit of losses and heat generation of a single energy channel, indirectly increasing the upper limit of operating power, and enabling the control system to select energy channels with different charging and discharging power according to different operating conditions and motor states. This solves the problem in the prior art where the armature winding used for both electric and generator operation is the same, i.e., the stator armature winding of the motor, for bidirectional energy transfer. The energy stored in a flywheel energy storage device depends mainly on the size and speed of the flywheel rotor, while its charging and discharging power depends on the power of the motor. If the motor power cannot be increased due to factors such as size and cost, it directly limits the important indicator of the charging and discharging power of the flywheel energy storage device, and it cannot fully exert its important advantages in some application scenarios that require instantaneous high-power discharge.

[0035] 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.

[0036] 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 electric power generation separation, comprising a lower housing (1), wherein an upper housing (2) is fixedly connected to the top of the lower housing (1), and both the top of the lower housing (1) and the bottom of the upper housing (2) are provided with through holes, characterized in that: The lower housing (1) is provided with a first stator core (301), which is divided into upper and lower sections. Both upper and lower sections of the first stator core (301) are annular structures. An annular excitation winding (302) and a first armature winding (303) are sequentially embedded between the upper and lower sections of the first stator core (301) from the outside to the inside along the centered direction. Both upper and lower sections of the first stator core (301) are fixedly connected to the inner wall of the lower housing (1). A flywheel rotor (304) is rotatably connected inside the lower housing (1) and placed inside the annular first stator core (301). The flywheel rotor is made of iron. The upper housing (2) is rotatably connected to a rotor core (43), which is fixedly connected to a flywheel rotor (304) via a rotating shaft (5). The lower housing (1) is fixedly connected to a first radial mechanical bearing (6) on its inner bottom wall and to a magnetic bearing (7) on its inner top wall. The lower housing (1) is rotatably connected to the flywheel rotor (304) via the first radial mechanical bearing (6). The upper housing (2) is fixedly connected to a second radial mechanical bearing (8) on its top. The upper housing (2) is rotatably connected to the rotating shaft (5) via the second radial mechanical bearing (8).

2. The flywheel energy storage device with electric power generation separation according to claim 1, characterized in that: The upper housing (2) is fixedly connected to a second stator core (41) and a second armature winding (42). The second stator core (41) is fixedly connected to the upper housing (2). The second armature winding (42) is wound around the outside of the second stator core (41). The rotor core (43) is placed inside the second stator core (41) and the rotor core (43) is fixedly connected to the shaft (5).

3. The flywheel energy storage device with electric power generation separation according to claim 2, characterized in that: The magnetic bearing (7) includes a ferromagnetic ring (71) and a bearing excitation winding (72). The top of the ferromagnetic ring (71) is fixedly connected to the lower housing (1). A magnetic shielding material is provided between the ferromagnetic ring (71) and the inner top wall of the lower housing (1). The ferromagnetic ring (71) has a groove structure with the opening facing downward. The bearing excitation winding (72) is embedded inside the ferromagnetic ring (71). The flywheel rotor (304) is a ferromagnetic rotor, and the flywheel rotor (304) and the magnetic bearing (7) are critically attracted. The ratio of the outer diameter D1 of the ferromagnetic ring (71) to the outer diameter D2 of the flywheel rotor (304) is D1 = (0.8-0.9)D2. The ratio of the inner diameter D3 of the ferromagnetic ring (71) to the outer diameter D2 of the flywheel rotor (304) is the difference D3 = (0.5-0.6)D2. The ratio of the outer diameter D1 of the ferromagnetic ring (71) to the outer diameter D4 of the second stator core (41) is D1 = (10MM-20MM)+D4. The area of ​​the ferromagnetic ring (71) is less than or equal to the area of ​​the magnetic shielding material.

4. The flywheel energy storage device with electric power generation separation according to claim 1, characterized in that: The lower housing (1) is connected to the upper housing (2) at the stop, and a vacuum cavity is formed inside the lower housing (1) and the upper housing (2).

5. The flywheel energy storage device with electric power generation separation according to claim 2, characterized in that: The bottom of the rotating shaft (5) is fixedly connected to a boss, and the top of the flywheel rotor (304) is provided with a slot that matches the boss. The rotating shaft (5) and the flywheel rotor (304) are connected by threads through the boss and the slot.

6. The flywheel energy storage device with electric power generation separation according to claim 3, characterized in that: Both the first armature winding (303) and the second armature winding (42) are equipped with wiring devices and electrically connected to an external power source. The first armature winding (303) is a three-phase AC winding.

7. The flywheel energy storage device with electric power generation separation according to claim 2, characterized in that: The flywheel rotor (304) has several regular arc grooves on its annular surface, and the number of arc grooves is a multiple of the number of rotor pole pairs.

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