A device for primary frequency modulation of a wind turbine generator

Abstract

A device for wind turbine primary frequency modulation, including machine side converter and grid side converter, one side of the machine side converter is electrically connected with the grid side converter, the other side of the machine side converter is electrically connected with the permanent magnet synchronous generator, the input shaft of the permanent magnet synchronous generator is connected with the rotating shaft of the wind turbine, the air pressure energy storage unit includes energy storage side converter, air compressor, small steam turbine generator and gas tank. Through the cooperation between the power grid, servo motor, piston, rotating disc and energy storage side converter, the current of wind power is transmitted to the power grid through the machine side converter, and the current generated by high pressure gas energy storage is transmitted to the power grid through the energy storage side converter, so as to realize the frequency modulation process, effectively avoid the problem that the current flywheel energy storage technology is not very mature, and the flywheel is usually made of carbon fiber material, which is not suitable for the large range and large quantity of wind turbine use requirements from the processing difficulty and cost.

Description

Technical Field

[0001] This utility model relates to the field of wind turbine frequency regulation technology, and in particular to a device for primary frequency regulation of wind turbines. Background Technology

[0002] As the proportion of wind power in the power grid increases, the inertial response level of the power grid decreases, making it unable to quickly provide active power support to the power grid when the grid frequency changes. Wind turbines cannot respond to changes in grid frequency. Due to the use of power electronic converters, the frequency of the inverter output AC power and the motor speed are no longer coupled. Therefore, it is necessary to design a frequency regulation structure, such as the device for primary frequency regulation of wind turbines with application number "202323197739.X", which includes a direct-drive permanent magnet wind turbine generator and a flywheel energy storage unit.

[0003] However, although it can effectively improve the frequency stability of the grid while ensuring that the system's wind energy utilization rate is not reduced, its ability to store excess electrical energy for frequency regulation is currently not very mature. Furthermore, flywheel energy storage is usually made of carbon fiber materials, which is not suitable for the large-scale and large-volume use of wind turbine generators due to both processing difficulty and cost. At the same time, the flywheel energy storage structure cannot further improve the power generation efficiency. Summary of the Invention

[0004] This invention aims to address the existing problems of the current flywheel energy storage technology not being very mature, and the fact that flywheels are usually made of carbon fiber materials, which are not suitable for the large-scale and high-volume use of wind turbine generators due to both processing difficulty and cost. At the same time, the flywheel energy storage structure cannot further improve the power generation effect. This invention provides a device for primary frequency regulation of wind turbine generators.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: This device for primary frequency regulation of wind turbine units includes a turbine-side converter and a grid-side converter. One side of the turbine-side converter is electrically connected to the grid-side converter, and the other side of the turbine-side converter is electrically connected to a permanent magnet synchronous generator. The input shaft of the permanent magnet synchronous generator is connected to the rotating shaft of the wind turbine generator. The DC link between the turbine-side converter and the grid-side converter is connected in parallel with a pneumatic energy storage unit. The pneumatic energy storage unit includes an energy storage-side converter, an air compressor, a small steam turbine generator, and an air storage tank.

[0006] To further improve the design, the air compressor includes a bracket and a crank. A piston is fitted to the inner wall of the bracket. Both sides of the crank are rotatably connected to the piston and the turntable respectively via pins. The rotating part of the turntable is fixedly connected to the output shaft of the servo motor. A three-way pipe is fixedly connected to the upper center of the bracket. One-way valves are installed on both outer walls of the three-way pipe.

[0007] Further improvements include connecting one side of the three-way pipe to the air inlet pipe of the gas storage tank, and connecting the lower part of the gas storage tank to the exhaust pipe of the solenoid valve via a small steam turbine generator.

[0008] To further improve the design, multiple heat-conducting grids are fixedly connected to the upper end of the gas storage box, and the lower part of the heat-conducting grids extends into the interior of the gas storage box. The upper surface of the heat-conducting grids is coated with a heat-absorbing coating.

[0009] Further improvements include an electrical connection on one side of the grid-side converter to a transformer, which is electrically connected to the power grid.

[0010] The beneficial effects of this utility model are as follows: Through the coordination of the power grid, servo motor, air compressor, piston, turntable, and energy storage-side converter, when the current generated by the generator exceeds the current required by the power grid, the generator-side converter can transmit the excess current to the parallel-connected energy storage-side converter. This allows the energy storage-side converter to drive the servo motor in the air compressor, which in turn drives the turntable and crank to move the piston up and down reciprocally. This allows high-pressure gas to be stored inside the air tank, converting excess electrical energy into high-pressure air energy for storage. When the current generated by the generator is less than the current required by the power grid, the system controls... The valve at the exhaust pipe of the gas storage tank is opened, and the high-pressure gas inside is discharged to the small steam turbine generator. The airflow drives the turbine to rotate, thereby generating electricity. The current is then transmitted to the grid-side converter through the energy storage side converter. The current generated by wind power generation and the current generated by high-pressure gas energy storage are jointly transmitted to the grid through the energy storage side converter. This achieves frequency regulation and effectively avoids the problems that the current flywheel energy storage technology is not very mature. In addition, flywheels are usually made of carbon fiber materials, which are not suitable for the large-scale and large-volume use of wind turbine generator sets due to their processing difficulty and cost.

[0011] Through the combination of the gas storage tank, heat-absorbing coating, and heat-conducting grid, the heat-conducting grid, made of copper and used with heat-absorbing coating, can directly absorb heat under sunlight, allowing the heat to be conducted to the interior of the gas storage tank to heat the high-pressure air inside. This causes the gas to expand and further enhances its power generation effect when combined with a small steam turbine generator, effectively avoiding the problem that flywheel energy storage structures cannot further improve power generation. Attached Figure Description

[0012] Figure 1This is a schematic diagram of the circuit structure of this utility model;

[0013] Figure 2 This is a schematic diagram of the energy storage structure in this utility model;

[0014] Figure 3 This utility model Figure 2 A schematic diagram of the rear view structure in the diagram;

[0015] Figure 4 This utility model Figure 3 A schematic diagram of the main view structure in the image;

[0016] Figure 5 This utility model Figure 4 A partial sectional view diagram.

[0017] Explanation of reference numerals in the attached diagram: 1. Wind turbine generator; 2. Permanent magnet synchronous generator; 3. Generator-side converter; 4. Grid-side converter; 5. Transformer; 6. Power grid; 7. Energy storage-side converter; 8. Air compressor; 9. Small steam turbine generator; 10. Air storage tank; 11. Heat-conducting grid; 12. Heat-absorbing coating; 13. One-way valve; 14. T-pipe; 15. Support; 16. Turntable; 17. Crank; 18. Piston; 19. Servo motor. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings:

[0019] See attached document Figure 1-5 In this embodiment, a device for primary frequency regulation of a wind turbine includes a turbine-side converter 3 and a grid-side converter 4. One side of the turbine-side converter 3 is electrically connected to the grid-side converter 4, and the other side of the turbine-side converter 3 is electrically connected to a permanent magnet synchronous generator 2. The models of the turbine-side converter 3, the energy storage-side converter 7, and the grid-side converter 4 can be determined according to specific usage requirements. The model of the permanent magnet synchronous generator 2 can be determined according to specific usage conditions. The input shaft of the permanent magnet synchronous generator 2 is connected to the rotating shaft of the wind turbine generator 1. The DC link between the turbine-side converter 3 and the grid-side converter 4 is connected in parallel with a pneumatic energy storage unit. The pneumatic energy storage unit includes an energy storage-side converter 7, an air compressor 8, a small steam turbine generator 9, and an air storage tank 10. One side of the grid-side converter 4 is electrically connected to a transformer 5, and the transformer 5 is electrically connected to a power grid 6.

[0020] See attached document Figure 1-5In this embodiment, the air compressor 8 includes a bracket 15 and a crank 17. A piston 18 is fitted to the inner wall of the bracket 15, allowing the piston 18 to move within the inner wall of the bracket 15 while maintaining relative sealing during movement. Both sides of the crank 17 are rotatably connected to the piston 18 and the turntable 16 respectively via pins. The rotating part of the turntable 16 is fixedly connected to the output shaft of the servo motor 19. A three-way pipe 14 is fixedly connected to the center of the upper end of the bracket 15. One-way valves 13 are installed on the outer walls of both sides of the three-way pipe 14. One side of 14 is connected to the air inlet pipe of the gas storage tank 10. The lower part of the gas storage tank 10 is connected to the small steam turbine generator 9 through the exhaust pipe of the solenoid valve. Multiple heat-conducting grids 11 are fixed to the upper end of the gas storage tank 10. The heat-conducting grids 11 can be made of copper and are used to absorb heat to heat and expand the gas inside the gas storage tank 10. The lower part of the heat-conducting grids 11 extends into the interior of the gas storage tank 10. The upper surface of the heat-conducting grids 11 is coated with heat-absorbing paint 12. The material of the heat-absorbing paint 12 can be selected according to the requirements.

[0021] Working principle:

[0022] When this device is needed for primary frequency regulation of wind turbine units, the overall structure is assembled. During use, the rotation of the blades of the wind turbine 1 drives the input shaft of the permanent magnet synchronous generator 2 to generate electricity. Under normal use, the current generated is transmitted to the grid-side converter 4 through the machine-side converter 3, and finally transmitted to the power grid 6 for daily use after being regulated by the transformer 5. When the current generated exceeds the current required by the power grid 6, the machine-side converter 3 can transmit the excess current to the parallel energy storage-side converter 7, which drives the servo motor 19 in the air compressor 8. The servo motor 19 drives the turntable 16 and the crank 17 to drive the piston 18 to move up and down reciprocally. With the help of the one-way valves 13 on both sides, the airflow can only flow from the outside to the air storage tank 10. The piston 18 continuously draws in air and pressurizes it before discharging it into the air storage tank 10, so that the air storage tank 10 stores high-pressure gas, converting excess electrical energy into high-pressure air energy for storage.

[0023] Meanwhile, the heat-conducting grid 11, made of copper and coated with heat-absorbing paint 12, can directly absorb heat under sunlight, allowing the heat to be conducted to the interior of the gas storage tank 10 to heat the internal high-pressure air. This causes the gas to expand, further increasing its power generation efficiency when combined with the small steam turbine generator 9. When the current generated by the generator is less than the current required by the grid 6, the valve at the exhaust pipe of the gas storage tank 10 is opened, and the internal high-pressure gas is discharged to the small steam turbine generator 9. The airflow drives the turbine to rotate, thereby generating electricity. The current is then transmitted to the grid-side converter 4 through the energy storage-side converter 7. Thus, the current generated by the wind power generation is transmitted to the grid 6 through the generator-side converter 3 and the current generated by the high-pressure gas energy storage through the energy storage-side converter 7. This achieves the frequency regulation process. Compared to existing technologies that use flywheel energy storage to store excess electrical energy for frequency regulation, current flywheel energy storage technology is not very mature. Furthermore, flywheels are typically made of carbon fiber, which is unsuitable for the large-scale, high-volume use of wind turbines due to both processing difficulty and cost. Therefore, this design utilizes an air energy storage structure. Currently, air energy storage combined with a steam turbine generator for air power generation is entirely feasible, and the materials and costs of structures such as pistons can be controlled within a reasonable range. This effectively avoids the problems of current flywheel energy storage technology being immature and flywheels typically made of carbon fiber being unsuitable for the large-scale, high-volume use of wind turbines due to both processing difficulty and cost.

[0024] The heat-conducting grid 11, made of copper and equipped with heat-absorbing coating 12, can directly absorb heat under sunlight, allowing the heat to be conducted to the interior of the gas storage tank 10 to heat the high-pressure air inside. This causes the gas to expand and further increase its power generation effect when combined with the small steam turbine generator 9, effectively avoiding the problem that the flywheel energy storage structure cannot further improve the power generation effect.

[0025] Although the present invention has been illustrated and described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail are possible within the scope of the claims.

Claims

1. A device for primary frequency regulation of a wind turbine generator, comprising a turbine-side converter (3) and a grid-side converter (4), wherein one side of the turbine-side converter (3) is electrically connected to the grid-side converter (4), characterized in that: The other side of the machine-side converter (3) is electrically connected to the permanent magnet synchronous generator (2). The input shaft of the permanent magnet synchronous generator (2) is connected to the rotating shaft of the wind turbine generator (1). The DC link between the machine-side converter (3) and the grid-side converter (4) is connected in parallel with the gas pressure energy storage unit. The gas pressure energy storage unit includes an energy storage-side converter (7), an air compressor (8), a small steam turbine generator (9), and an air storage tank (10).

2. The device for primary frequency regulation of wind turbine generators according to claim 1, characterized in that: The air compressor (8) includes a bracket (15) and a crank (17). A piston (18) is attached to the inner wall of the bracket (15). Both sides of the crank (17) are rotatably connected to the piston (18) and the turntable (16) respectively by pins. The rotating part of the turntable (16) is fixedly connected to the output shaft of the servo motor (19). A three-way pipe (14) is fixedly connected to the center of the upper end of the bracket (15). One-way valves (13) are installed on the outer walls of both sides of the three-way pipe (14).

3. The device for primary frequency regulation of wind turbine generators according to claim 2, characterized in that: One side of the three-way pipe (14) is connected to the air inlet pipe of the air storage tank (10), and the lower part of the air storage tank (10) is connected to the small steam turbine generator (9) through the exhaust pipe of the solenoid valve.

4. The device for primary frequency regulation of wind turbine generators according to claim 1, characterized in that: The upper end of the gas storage box (10) is fixed with a plurality of heat-conducting grids (11), the lower part of the heat-conducting grids (11) extends into the interior of the gas storage box (10), and the upper surface of the heat-conducting grids (11) is sprayed with heat-absorbing coating (12).

5. The device for primary frequency regulation of wind turbine generators according to claim 1, characterized in that: One side of the grid-side converter (4) is electrically connected to the transformer (5), and the transformer (5) is electrically connected to the power grid (6).

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