Method for regulating load by gravity energy storage unit motion mechanism based on power grid dispatching

Abstract

This invention discloses a method for load regulation based on grid dispatching of a gravity energy storage unit's dynamic mechanism. The method includes: maintaining a consistent relative height of the mass blocks in the gravity energy storage system via a PLC controller; when the grid dispatching mode is valley filling, the grid dispatching system sends a start command, the gravity energy storage system executes a charging mode, and the generator drives the left and right main shafts to lift the elevator carrying the mass blocks to the energy storage height via an elevator traction belt; when the grid dispatching mode is peak shaving, the optimal mass block descent method is selected; the system uses a visual camera to dynamically scan markings on the side beams of the trolley's path to obtain the trolley's travel status and predict the time it takes for the trolley to reach the mass blocks; and the method for the mass blocks to descent in the next cycle is determined based on the trolley's arrival time at the mass blocks. This method can quickly respond to the grid's peak shaving demands, ensuring the continuity of potential energy conversion and the stability of the gravity energy storage system's output power.

Description

Technical Field

[0001] This invention relates to the field of gravity energy storage system control technology, and more specifically, to a method for adjusting the load by linkage of the moving mechanism of a gravity energy storage unit based on grid dispatch. Background Technology

[0002] With the introduction of the "dual carbon" target, the scale of renewable energy continues to expand. Conventional energy storage methods have few control monitoring points, and the control methods mainly rely on data monitoring and analog quantity regulation. Conventional energy storage control methods are usually distributed, with each unit typically using independent control methods, and there are few functional requirements for cross-sequential control between unit devices.

[0003] Compared with conventional energy storage systems, such as photovoltaic energy storage, wind energy storage, and chemical energy storage, gravity energy storage is a new technology with more control measurement points and a large number of cross-references in the sequential control of equipment within the unit. The positioning requirements of the moving mechanism are high, and the power demand on the grid side corresponds to the complex adjustment conditions of the gravity energy storage system itself. In order to meet the control needs of gravity energy storage system, it is urgent to find a suitable control method for the moving mechanism of gravity energy storage unit. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for load regulation by linkage of the dynamic mechanism of a gravity energy storage unit based on power grid dispatch.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for load regulation by linkage of a gravity energy storage unit's moving mechanism based on power grid dispatching, specifically including the following steps:

[0006] (1) In a gravity energy storage system, the relative height of each mass block is kept consistent by a PLC controller;

[0007] (2) When the grid dispatching mode is valley filling operation mode, the grid dispatching sends a start command, the gravity energy storage system executes the charging mode, and the generator drives the left and right main shafts to lift the elevator loaded with mass blocks to the energy storage height through the elevator traction belt; when the grid dispatching mode is peak shaving operation mode, the optimal mass block falling mode is selected.

[0008] (3) The markings set on the side beam of the trolley channel are scanned by a visual camera to obtain the trolley's driving status and predict the time it takes for the trolley to reach the mass block.

[0009] (4) Determine the falling method of the mass block in the next cycle based on the time it takes for the trolley to reach the mass block;

[0010] (5) Repeat steps (2)-(4) until the grid dispatch needs are met.

[0011] Furthermore, when the grid dispatching mode is peak shaving operation mode, the specific process of selecting the optimal mass block movement mode is as follows: the grid dispatching sends a start command, the gravity energy storage system executes the discharge mode, the generator drives the left and right main shafts to lower the elevator loaded with mass blocks to the energy release height h through the elevator traction belt, and the energy consumption required to lift each mass block is preset according to the potential energy formula Ws=mgh÷η; the power required to lift each mass block is calculated by the mass block falling time t when the generator releases energy Ps=Ws÷t; according to the power consumption P of the grid, the number of mass blocks dropped by the motor in one go [X]=P÷Ps is calculated; where m is the mass block coefficient, g is the gravitational acceleration constant, η is the loss coefficient, and [] indicates upward evenness.

[0012] Furthermore, the number of mass blocks dropped in a single operation is arranged symmetrically from the inside to the outside on both sides of the generator.

[0013] Furthermore, step (3) includes the following sub-steps:

[0014] (31) Set up identification codes on the side beams and collect images of the identification codes through a camera on the traveling trolley;

[0015] (32) Convert the gray values ​​of each pixel in the acquired identification code image from analog to discrete to obtain an RGB format image, and perform noise reduction processing through median filtering.

[0016] (33) Convert the denoised RGB format image into YCrCb format data;

[0017] (34) Represent each pixel with coordinates, fix its relative position, and write the YCrCb format data of each pixel in the form of a label to mark the position, thereby obtaining image data with position information and YCrCb information;

[0018] (35) Based on the image data with location information and YCrCb information, the mass block pixels are classified: when the mass block pixels account for 50-100%, the car decelerates uniformly to 0; when the mass block pixels account for 25-50%, the car travels at a constant speed; when the mass block pixels account for 0-25%, the car accelerates uniformly.

[0019] (36) Based on the pixel classification of the mass block, predict the time it takes for the car to travel to the mass block.

[0020] Furthermore, the prediction process for the time it takes for the trolley to reach the mass block is as follows:

[0021] Tv=Vt / a1+Vt / a2+(S-S1-S2) / Vt

[0022] Among them, Vt is the maximum speed of the trolley, a1 is the acceleration of uniform acceleration, a2 is the acceleration of uniform deceleration, S is the length of the side beam of the trolley channel, S1 is the distance traveled by the trolley with uniform acceleration, and S2 is the distance traveled by the trolley with uniform deceleration.

[0023] Furthermore, the implementation process of step (4) is as follows:

[0024] (4.1) When 2Tv < T1 + T2 + Tw×n, operate according to the optimal mass block falling method determined by the power grid scheduling requirements of the next cycle as the mass block falling method of the next cycle;

[0025] (4.2) When 2Tv ≥ T1 + T2 + Tw×n, use the mass block falling method that is one level worse than the optimal mass block falling method calculated according to the power grid scheduling requirements of the next cycle as the mass block falling method of the next cycle; the reduced falling mass blocks are respectively located at the outermost sides of the symmetrically falling mass blocks on the left and right sides of the generator; [[ID=A]] [[ID=B]]

[0026] Among them, T1 is the mass block descent time, T2 is the elevator ascent time, Tw is the trolley waiting time, n is the number of descending elevator groups, and Tv is the time for the trolley to travel to the mass block.

[0027] Furthermore, the trolley waiting time Tw = T - (T1 + T2), where T is the maximum load regulation time.

[0028] Furthermore, the maximum load regulation time T = T1×n×η, where η is the loss coefficient.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The method for联动调节负载 of the gravity energy storage unit driving mechanism in the present invention provides a method for the action of converting gravitational potential energy under the premise that the falling speed of the mass block in the gravity energy storage system cannot be increased, for the peak period of the corresponding power consumption load of the power grid. When the power grid scheduling method is the peak shaving operation mode, by selecting the optimal mass block falling method and combining the predicted time for the trolley to travel to the mass block to adjust the mass block falling method of the next cycle, a solution is provided to meet the power grid peak shaving demand and maintain the continuous output of electric energy by the gravity energy storage device, providing guarantee for the stable and continuous falling of the mass block in the gravity energy storage system; and the number of mass blocks released each time is carried out in the order from the inside to the outside symmetrically on the left and right sides of the generator, so that the gravity energy storage system can meet the requirements of maintaining the structural force balance on both sides of the gravity energy storage device itself and responding to the load fluctuation demand on the power grid side. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flowchart of the method for联动调节负载 of the gravity energy storage unit based on power grid scheduling in the present invention;

[0031] It should be noted that there is an unclear "联动调节负载" in the original text. You may need to check and clarify this part for a more accurate translation. Figure 2 This is a diagram illustrating the falling pattern of the dual mass blocks when the power grid dispatching mode is peak shaving operation in this invention.

[0032] Figure 3 This is a diagram showing the falling pattern of the four mass blocks when the power grid dispatching mode is peak shaving operation in this invention;

[0033] Figure 4 This is a diagram showing the falling pattern of the six mass blocks when the power grid dispatching mode is peak shaving operation in this invention;

[0034] Figure 5 This is a diagram showing the falling pattern of the eight mass blocks when the power grid dispatching mode is peak shaving operation in this invention;

[0035] Figure 6 This is a diagram showing the falling pattern of the twelve mass blocks when the power grid dispatching mode is peak shaving operation in this invention. Detailed Implementation

[0036] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings.

[0037] like Figure 1 This is a flowchart of the load regulation method for the linkage of the moving mechanism of a gravity energy storage unit based on power grid dispatch according to the present invention. The load regulation method for the linkage of the moving mechanism of a gravity energy storage unit specifically includes the following steps:

[0038] (1) The gravitational potential energy of each mass block depends on the mass of the mass block and the energy release height of each mass block. Considering the smoothness of the mechanical potential energy loaded by the generator when the mass block falls, the potential energy loaded by the generator on each mass block should be kept consistent. Therefore, in the gravity energy storage system, the relative height of each mass block is kept consistent through the PLC controller.

[0039] (2) When the power grid dispatching mode is valley filling operation, the power grid dispatching sends a start command, the gravity energy storage system executes charging mode, and the generator drives the left and right main shafts to lift the elevator loaded with mass blocks to the energy storage height via the elevator traction belt, such as Figure 2 As shown, the motor is usually at maximum power during the valley filling period, as long as there are 12 mass blocks in the lifting state at the same time.

[0040] When the power grid dispatching mode is peak shaving operation, in order to respond to the power grid demand as quickly as possible, the goal of selecting the optimal mass block dropping mode is to continuously output the active power of the generator. Specifically, the power grid dispatching sends a start command, the gravity energy storage system executes the discharge mode, the generator drives the main shafts on both sides to lower the elevator loaded with mass blocks to the energy release height h through the elevator traction belt, and the energy consumption required to lift each mass block is preset according to the potential energy formula Ws=mgh÷η; the power required to lift each mass block is calculated by the mass block falling time t when the generator releases energy Ps=Ws÷t; according to the power consumption P of the power grid, the number of mass blocks dropped by the motor in one go [X]=P÷Ps is calculated, and the number of mass blocks dropped in one go is arranged symmetrically from the inside to the outside on both sides of the generator; where m is the mass block coefficient, g is the gravitational acceleration constant, η is the loss coefficient, and [] indicates upward evenness.

[0041] Taking a gravity energy storage system with 24 mass blocks as an example, when operating in a dual-mass-block dropping mode, one mass block falls from each side of the generator, and the generator operates continuously for the longest period of time. Figure 3 When operating with a four-mass-block drop method, two masses fall from each of the left and right sides of the generator. In this case, the generator's continuous power generation time will be shortened to half of its longest operating time. Figure 4 When operating with a six-mass-block drop method, three masses fall on each of the left and right sides of the generator. In this case, the generator's continuous power generation time will be shortened to one-third of its longest operating time. Figure 5 When operating with an eight-mass-block drop method, four masses fall from each of the left and right sides of the generator. In this case, the generator's continuous power generation time will be shortened to 1 / 4 of its longest operating time. Figure 6 When operating in the twelve-mass-block-drop mode, six mass blocks fall on each of the left and right sides of the generator. At this time, the generator's continuous power generation time will be shortened to 1 / 6 of the longest operating time. The shorter the generator's continuous power generation time, the higher the level of the mass block-drop mode.

[0042] (3) The continuous falling of the mass block is a constraint on the falling mode of the mass block. In order to ensure that the mass block can fall continuously, the time limit for the horizontal trolley to transport the mass block back and forth limits the maximum number of mass blocks that can fall in each cycle. Therefore, the markings set on the side beam of the trolley channel are scanned by a visual camera to obtain the driving status of the trolley and predict the time for the trolley to reach the mass block. The specific steps include the following:

[0043] (31) Set up identification codes on the side beams and collect images of the identification codes through a camera on the traveling trolley;

[0044] (32) Convert the gray values of each pixel of the collected identification code image from analog to discrete to obtain an RGB format image, and perform noise reduction processing through median filtering;

[0045] (33) Convert the noise-reduced RGB format image into YCrCb format data;

[0046] (34) Represent each pixel point by coordinates, fix its relative position, and write the YCrCb format data of each pixel point in the form of a label to mark the position, obtaining image data with position information and YCrCb information;

[0047] (35) According to the image data with position information and YCrCb information, classify the quality block pixels: when the proportion of quality block pixels is 50 - 100%, the trolley decelerates uniformly until the speed is 0; when the proportion of quality block pixels is 25 - 50%, the trolley travels at a constant speed; when the proportion of quality block pixels is 0 - 25%, the trolley accelerates uniformly; controlling the acceleration and deceleration of the trolley by the proportion of quality block pixels can enable the trolley, when loading and transporting quality blocks, to control the acceleration and deceleration actions of the trolley through the proportion of pixels in the front view of the trolley, and can also be used as an obstacle avoidance signal to forcibly stop the trolley when approaching an obstacle or below the quality block spacing distance, ensuring that there is a risk of collision for the loaded quality blocks.

[0048] (36) According to the classification of the quality block pixels, predict the time Tv when the trolley travels to the quality block, Tv = Vt / a1 + Vt / a2 + (S - S1 - S2) / Vt,

[0049] where Vt is the maximum speed of the trolley, a1 is the acceleration during uniform acceleration, a2 is the acceleration during uniform deceleration, S is the length of the side beam of the trolley channel, S1 is the distance traveled by the trolley during uniform acceleration, and S2 is the distance traveled by the trolley during uniform deceleration.

[0050] (4) Since the relative height of the quality block falling remains the same, the elevator goes to each floor in turn to catch the quality block and then drops it. According to the time when the trolley travels to the quality block, ensure that the quality block has reached the交接 position when the elevator reaches the upper position. Therefore, determine the falling mode of the quality block in the next cycle according to the time when the trolley travels to the quality block; the specific process is as follows:

[0051] (4.1) According to the operating characteristics of the gravity energy storage system, a single energy-stored quality block has only one action of falling and releasing energy in one charge-discharge cycle. To ensure that each elevator can continuously drop quality blocks, it is necessary to satisfy 2Tv < T1 + T2 + Tw×n, then determine the optimal falling mode of the quality block according to the power grid scheduling requirements in the next cycle as the falling mode of the quality block in the next cycle.

[0052] (4.2) When 2Tv≥T1+T2+Tw×n, the optimal mass block dropping method calculated based on the grid dispatch demand of the next cycle is adopted as the mass block dropping method of the next cycle, which is one level worse than the optimal mass block dropping method; the mass blocks that reduce the dropping are located on the outermost side of the symmetrically dropping mass blocks on the left and right sides of the generator.

[0053] Where T1 is the descent time of the mass block, T2 is the ascent time of the elevator, Tw is the waiting time of the trolley, Tw = T - (T1 + T2). To ensure stable power output when the generator is working, in the maximum power output mode, n / 2 of the elevators are falling simultaneously, while the other half are in the lifting state. In the motion state, there is a waiting time Tw after each elevator descends to its position and then rises to the top; T is the maximum load adjustment time, T = T1 × n × η, where η is the loss coefficient, n is the number of elevator groups descending, and Tv is the time it takes for the trolley to travel to the mass block;

[0054] Taking a gravity energy storage system with 24 mass blocks as an example, if the optimal mass block dropping method calculated based on the grid dispatch demand of the next cycle is a four-mass-block dropping method, then a two-mass-block dropping method will be used in the next cycle; if the optimal mass block dropping method calculated based on the grid dispatch demand of the next cycle is a six-mass-block dropping method, then a four-mass-block dropping method will be used in the next cycle; if the optimal mass block dropping method calculated based on the grid dispatch demand of the next cycle is an eight-mass-block dropping method, then a six-mass-block dropping method will be used in the next cycle; and if the optimal mass block dropping method calculated based on the grid dispatch demand of the next cycle is a twelve-mass-block dropping method, then an eight-mass-block dropping method will be used in the next cycle. By reducing the number of dropping mass blocks, the output power is gradually reduced.

[0055] (5) Repeat steps (2)-(4) until the grid dispatch needs are met.

[0056] This invention relates to a load regulation method based on the linkage of the dynamic mechanism of a gravity energy storage unit in grid dispatch. When the grid dispatch mode is in peak shaving operation, the method adjusts the falling mode of the mass block in the next cycle by selecting the optimal mass block falling mode and combining it with the predicted time for the trolley to reach the mass block. This can quickly respond to the grid's peak shaving demand, ensure the continuity of potential energy conversion, and thus guarantee the stability of the output power of the gravity energy storage system.

[0057] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for load regulation by linkage of the dynamic mechanism of a gravity energy storage unit based on power grid dispatch, characterized in that, Specifically, the steps include the following: (1) In the gravity energy storage system, the relative height of each mass block is kept consistent by a PLC controller; (2) When the grid dispatching mode is valley filling operation mode, the grid dispatching sends a start command, the gravity energy storage system executes the charging mode, and the generator drives the left and right main shafts to lift the elevator loaded with mass blocks to the energy storage height through the elevator traction belt; when the grid dispatching mode is peak shaving operation mode, the optimal mass block falling mode is selected. When the power grid dispatching mode is peak shaving operation, the specific process of selecting the optimal mass block movement mode is as follows: the power grid dispatching sends a start command, the gravity energy storage system executes the discharge mode, the generator drives the left and right main shafts to lower the elevator loaded with mass blocks to the energy release height h through the elevator traction belt, and the energy consumption required to lift each mass block is preset according to the potential energy formula Ws=mgh÷η; the power required to lift each mass block is calculated by the mass block falling time t when the generator releases energy Ps=Ws÷t; the number of mass blocks dropped by the motor in one go is calculated by the power grid power consumption P [X]=P÷Ps; where m is the mass block coefficient, g is the gravitational acceleration constant, η is the loss coefficient, and [] indicates upward evenness; The number of mass blocks dropped in a single operation is arranged symmetrically from the inside to the outside on both sides of the generator. (3) The markings set on the side beam of the trolley channel are scanned by a visual camera to obtain the trolley's driving status and predict the time it takes for the trolley to reach the mass block. (4) Determine the falling pattern of the mass block in the next cycle based on the time it takes for the trolley to reach the mass block; (5) Repeat steps (2)-(4) until the grid dispatch needs are met.

2. The method for load regulation by linkage of gravity energy storage unit dynamic mechanism based on power grid dispatch according to claim 1, characterized in that, Step (3) includes the following sub-steps: (31) Set up identification codes on the side beams and collect images of the identification codes using a camera on the traveling trolley; (32) Convert the gray values ​​of each pixel in the acquired identification code image from analog to discrete to obtain an RGB format image, and perform noise reduction processing by median filtering; (33) Convert the denoised RGB format image into YCrCb format data; (34) Represent each pixel with coordinates, fix its relative position, and write the YCrCb format data of each pixel in the form of a label to mark the position, thereby obtaining image data with position information and YCrCb information; (35) Based on the image data with location information and YCrCb information, the mass block pixels are classified: when the mass block pixels account for 50-100%, the car decelerates uniformly to 0; when the mass block pixels account for 25-50%, the car moves at a constant speed; when the mass block pixels account for 0-25%, the car accelerates uniformly. (36) Based on the classification of the pixels of the mass block, predict the time it takes for the car to travel to the mass block.

3. The method for load regulation by linkage of gravity energy storage unit moving mechanism based on power grid dispatch according to claim 2, characterized in that, The process for predicting the time it takes for the trolley to reach the mass block is as follows: Tv = Vt / a1 + Vt / a2 + (S - S1 - S2) / Vt Among them, Vt is the maximum speed of the trolley, a1 is the acceleration of uniform acceleration, a2 is the acceleration of uniform deceleration, S is the length of the side beam of the trolley channel, S1 is the distance traveled by the trolley with uniform acceleration, and S2 is the distance traveled by the trolley with uniform deceleration.

4. The method for load regulation by linkage of gravity energy storage unit dynamic mechanism based on power grid dispatch according to claim 1, characterized in that, The implementation process of step (4) is as follows: (4.1) When 2Tv < T1 + T2 + Tw×n, the optimal mass block falling mode determined according to the power grid scheduling requirements of the next cycle is used as the mass block falling mode of the next cycle; (4.2) When 2Tv ≥ T1 + T2 + Tw×n, the optimal mass block falling mode calculated according to the power grid scheduling requirements of the next cycle is used, and the mass block falling mode one level worse than the optimal mass block falling mode is used as the mass block falling mode of the next cycle; the reduced falling mass blocks are respectively located at the outermost sides of the symmetrically falling mass blocks on the left and right sides of the generator; Among them, T1 is the mass block descent time, T2 is the elevator ascent time, Tw is the trolley waiting time, n is the number of descending elevator groups, and Tv is the time for the trolley to travel to the mass block.

5. The method for load regulation by linkage of the dynamic mechanism of a gravity energy storage unit based on power grid dispatch according to claim 4, characterized in that, The trolley waiting time Tw = T - (T1 + T2), where T is the maximum load regulation time.

6. The method for load regulation by linkage of the dynamic mechanism of a gravity energy storage unit based on power grid dispatch according to claim 5, characterized in that, The maximum load regulation time T = T1×n×η, where η is the loss coefficient.

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