Power smooth control method applied to chain transmission gravity energy storage system

Abstract

The invention discloses a power smooth control method applied to a chain transmission gravity energy storage system. The method comprises the following steps: acquiring active power, flywheel rotating speed and truck data of a grid-connected point at a power grid side; based on a system physical model, real-time active power and truck data, a total fluctuation power prediction sequence containing multiple fluctuation superposition in a period of time in the future is predicted, and the total fluctuation power prediction sequence is updated and iterated according to historical measurement power data. And according to the current flywheel rotating speed and the predicted fluctuation power, calculating a flywheel optimal rotating speed sequence for smoothing the grid-connected power of the whole hybrid energy storage system in a future period of time. And adjusting the flywheel energy storage device according to the flywheel optimal rotating speed sequence, and outputting corresponding compensation power to a power grid to realize power balance. By using the method, the total fluctuation power including multiple fluctuation superposition of the system can be actively predicted and prospectively and accurately compensated, and high-quality smooth output of the grid-connected power is realized. The method can be widely applied to the technical field of new energy storage and intelligent power grids.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new energy storage and smart grid technology, and particularly relates to a power smoothing control method applied to a chain drive gravity energy storage system. BACKGROUND

[0002] As a new type of physical energy storage, gravity energy storage has the advantages of long service life, high safety and environmental friendliness. Among them, the scheme of using a chain drive mechanism to cyclically pull a heavy vehicle can realize continuous energy storage and release. However, the energy storage system has inherent power fluctuation problems during operation, mainly due to: the inherent "polygon effect" of the chain drive will cause high-frequency periodic fluctuations in transmission speed and load; the change in the number of heavy vehicles participating in the operation on the slope track will cause step fluctuations in the total load of the system, causing low-frequency power impact. These two types of fluctuations are transmitted to the motor end, which will cause the active power output to the grid to fluctuate continuously, seriously affecting power quality and grid stability.

[0003] To cope with the power fluctuations during system operation, the existing technology uses a flywheel or supercapacitor as an auxiliary energy storage device. By monitoring the active power data of the grid-side grid connection point in real time, when a power deviation is detected, the auxiliary energy storage device is controlled to absorb or release energy accordingly to maintain the stability of the grid-connected power. This method has a response lag problem, and the compensation effect is limited for high-frequency periodic power fluctuations (such as those caused by the polygon effect), and it is also difficult to cope with rapid step power changes. SUMMARY

[0004] Therefore, in order to solve the technical problem that the existing power compensation method applied to the chain drive gravity energy storage system mostly adjusts after detecting a power deviation, the present application proposes a power smoothing control method applied to the chain drive gravity energy storage system, which comprises the following steps: Real-time monitoring: Collecting active power, flywheel speed and heavy vehicle data at the grid-side grid connection point.

[0005] Fluctuation prediction: Based on the system physical model, real-time active power and heavy vehicle data, predicting a total fluctuation power prediction sequence containing multiple fluctuations superimposed in a future period of time, and updating it iteratively according to historical measured power data.

[0006] Speed optimization: According to the current flywheel speed and the predicted fluctuation power, calculating a flywheel optimal speed sequence for smoothing the grid-connected power of the entire hybrid energy storage system in a future period of time.

[0007] Power compensation: Adjusting the flywheel energy storage device according to the flywheel optimal speed sequence to output corresponding compensation power to the grid, achieving power balance.

[0008] Based on the above scheme, the application provides a power smoothing control method applied to a chain transmission gravity energy storage system, power fluctuation of the chain transmission gravity energy storage system in a future period of time is calculated through a power fluctuation prediction module, a model prediction control algorithm is used to calculate flywheel compensation power and an optimal speed sequence, and flywheel energy storage is avoided from compensating for power fluctuation lag of the system. From passive response to active offset, the operation power of the hybrid energy storage system is smoothed, and the power fluctuation problem in the operation process of the chain transmission gravity energy storage system is effectively solved. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a step flow chart of the power smoothing control method applied to the chain transmission gravity energy storage system of the application; Figure 2 is a partial structure schematic diagram of the chain transmission gravity energy storage system of the embodiment of the application. DETAILED DESCRIPTION

[0010] In the prior art, the power fluctuation phenomenon generated in the operation process of the chain transmission gravity energy storage system still exists, and the fluctuation is superimposed by different frequency components, including periodic fluctuation and step change, which affects the continuity and stability of the system output power.

[0011] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the application.

[0012] It should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings. The embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0013] It should be understood that the "system", "device", "unit" and / or "module" used in the application is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0014] Unless otherwise indicated, the use of "or" herein is the inclusive, and not the exclusive or. That is, a combination of "A" or "B" means "A" alone, "B" alone, or "A" and "B" together. Unless otherwise indicated, the use of conjunctions such as "and," "or," and "at least one of," are intended to mean an inclusive rather than an exclusive disjunction, that is, unless the context clearly indicates otherwise, the phrase "X employs A or B" means that X employs A, or B, or both. Similarly, the phrase "at least one of A or B" means that the phrase employs A, or B, or both. Unless otherwise noted, the use of conjunctive terms such as "and" or "and / or" is not intended to imply that an inclusive or exclusive disjunction of the conjunctive terms is intended. The use of the term "to" is not intended to limit the step or step to which the term "to" is applied to only the singular, but rather, the term "to" is intended to encompass both the singular and the plural. The use of the term "comprising" (and any form of comprising, such as "comprise" and "comprises"), or "having" (and any form of having, such as "have" and "has") is not intended to be limiting, such that a statement that an element is "comprising" or "having" something indicates that the element can further include other steps, elements, compartments, articles of manufacture, or components.

[0015] In the description of embodiments of the present application, "multiple" means two or more than two. The following terms "first", "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0016] In addition, flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or subsequent operations are not necessarily performed in sequence. On the contrary, each step can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0017] Referring to Figure 1 The flowchart of an optional example of the power smoothing control method applied to the chain drive gravity energy storage system proposed in the present application can be applied to a computer device. The control method proposed in the present embodiment can include but is not limited to the following steps: S0, system initialization; S1, real-time acquisition of active power data, flywheel speed, and load vehicle data at the grid-side grid-connected point of the chain drive gravity energy storage system; S2, calculation of total fluctuation power prediction sequence based on the physical model of the chain drive gravity energy storage system, active power data, and load vehicle data; S3, calculation of flywheel optimal speed sequence according to the flywheel speed and the total fluctuation power prediction sequence; S4, control of the flywheel energy storage device in the chain drive gravity energy storage system according to the flywheel optimal speed sequence, and output of compensation power; S5, cyclic steps S1 to S4, continuous updating of the compensation power output by the flywheel energy storage device.

[0018] In the chain drive gravity energy storage system in the specific embodiments of the present application, the gravity energy storage part refers to Figure 2The working process is as follows: the motor drives the chain wheel to rotate, the gear drives the chain to pull the load vehicle carrying the heavy block to move upward along the slope, in this process, the electric energy of the power grid is converted into the gravitational potential energy of the heavy block and the load vehicle, which is the energy storage process. The heavy block and the load vehicle move downward along the slope at a high place, the chain wheel is reversed through the chain, and then the motor is reversed to input the power grid, in this process, the gravitational potential energy of the heavy block and the load vehicle is converted into electric energy, which is the energy release process. In the energy storage and release process, the output power of the chain transmission gravity energy storage system fluctuates periodically, the speed of the flywheel is adjusted by the predicted compensation power to compensate the periodic fluctuation power of the chain transmission gravity energy storage system, so as to smooth the grid-connected power of the whole chain transmission gravity energy storage system.

[0019] In some feasible embodiments, step S1 specifically comprises: Input system parameters: slope inclination , slope length , slope height , chain wheel radius , number of chain wheel teeth , chain wheel tooth angle , overall mass of the load vehicle and the heavy block vehicle , linear speed of the load vehicle , flywheel moment of inertia , ideal working point of the flywheel , flywheel speed range , flywheel power range , power tracking term weight coefficient is set to , state penalty term weight coefficient , control action penalty term coefficient , flywheel speed control period , initial speed of the chain wheel , initial number of load vehicles , initial speed of the flywheel .

[0020] In some feasible embodiments, step S2 specifically comprises: "Active power data" refers to the instantaneous active power value measured at the grid connection point of the chain-driven gravity energy storage system connected to the public power grid, which reflects the actual power output of the hybrid energy storage system to the grid; "flywheel speed" refers to the angular velocity of the rotating body in the flywheel energy storage device at the current moment, in rad / s or r / min, used to characterize the current kinetic energy level stored in the flywheel; "cargo vehicle data" includes the number, location, linear velocity, and time information of the entry and exit of the inclined track of the cargo vehicles, used to characterize the current mechanical motion state and energy release / absorption trend of the gravity energy storage subsystem; the three types of data together constitute the observable input set of the system's real-time operating state, providing basic data support for subsequent fluctuation modeling and compensation decisions.

[0021] The calculation process for the final total fluctuation power prediction is as follows: in, This represents the final predicted total fluctuation power. This represents the measured total grid-connected power, i.e., the active power data of the grid-side grid connection point of the chain-driven gravity energy storage system collected in step S1; This refers to the low-frequency step power fluctuation when a truck enters or leaves the working ramp section. This refers to the high-frequency power fluctuations caused by the "polygonal effect" in chain drives.

[0022] The final total fluctuation power prediction value will be used for subsequent calculation of the optimal flywheel speed; High-frequency power fluctuations caused by the polygonal effect in chain drives The specific calculation method is as follows: in, This represents the amplitude of the high-frequency oscillation. The frequency of high-frequency oscillations. For phase; Amplitude of high-frequency oscillations The specific calculation method is as follows: in, For the number of trucks, For the weight of the truck and the heavy object, It is the acceleration due to gravity. To ensure a constant angular velocity of the sprocket during system operation, The sprocket pitch circle radius; This is the engagement phase angle; The tooth angle; The frequency of high-frequency oscillation is: in, The sprocket speed, This represents the number of sprocket teeth. in, For the overall weight of the truck, This is the transmission efficiency coefficient. For the running linear velocity, The slope angle is denoted by .

[0023] In addition, the total grid-connected power during operation It can also be calculated in the following ways: in, To provide a reference power output for gravity-based energy storage that ignores power fluctuations, This includes fluctuating power that contains both high and low frequencies. For the flywheel in The actual compensation power at any given time; The predicted total fluctuating power of the chain-driven gravity energy storage system over the next period is as follows: ; It should be noted that the relevant sequence is a series of data corresponding to the values.

[0024] This embodiment achieves structured modeling of the causes of power fluctuations by integrating physical models and real-time measurement data without requiring a large number of labeled samples. This makes the prediction results both mechanisticly reliable and timely, providing traceable and verifiable prior information on disturbances for flywheel compensation strategies.

[0025] In some feasible embodiments, step S3 specifically includes: The objective function for calculating the optimal flywheel speed sequence to smooth the grid-connected power of the entire hybrid energy storage system over a future period, using a model predictive control algorithm, is as follows: in, For grid-connected power setting value, For prediction The flywheel compensation speed at any given moment, The ideal operating speed of the flywheel. express The theoretical compensation power of the flywheel at any given moment. express The theoretical compensation power of the flywheel at any given moment. These are the weighting coefficients for the power tracking term. The weight coefficient for the state penalty term. To control the coefficient of the action penalty term, To predict the step size.

[0026] Its relevant constraints include: Flywheel speed constraint: Flywheel power constraints: Flywheel dynamics constraints: The flywheel speed prediction module iteratively solves for the optimal flywheel speed sequence, including error compensation, over a future period to smooth the grid-connected power of the entire hybrid energy storage system, resulting in... Optimal flywheel speed sequence within a step , , .

[0027] This embodiment incorporates the current flywheel state and disturbance prediction into the optimization framework, enabling the flywheel compensation strategy to combine feedforward initiative and feedback robustness, avoiding response lag caused by relying solely on error feedback, and improving the collaborative suppression capability against composite frequency fluctuations.

[0028] In some feasible embodiments, step S4 specifically includes: Will As the speed control command at the current moment; The speed of the flywheel energy storage device is controlled according to the speed command, so that its output power compensation smooths the power fluctuation of the chain-driven gravity energy storage system. The flywheel energy storage device operates under two different conditions based on the instantaneous power of the chain-driven gravity energy storage system, including: Energy release condition, at this time The flywheel decelerates and releases kinetic energy to compensate for the insufficient power of the chain drive's gravity-stored energy. Energy storage operating conditions, at this time The flywheel accelerates and absorbs kinetic energy, absorbing excess power stored in gravity by the chain drive. in, This indicates the actual power of the flywheel.

[0029] The instantaneous rate of change of the flywheel kinetic energy with respect to time during the change of flywheel speed is: .

[0030] This embodiment precisely maps high-level optimization instructions to low-level actuators, forming a "prediction-decision-execution" closed loop. This upgrades the flywheel energy storage device from a passive energy storage unit to an active power regulator, ultimately achieving full-frequency, high-precision, fast-response smooth control of grid-connected power fluctuations in the chain-driven gravity energy storage system.

[0031] A storage medium storing processor-executable instructions, which, when executed by a processor, are used to implement a power smoothing control method for a chain-driven gravity energy storage system as described above.

[0032] The content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0033] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A power smoothing control method applied to a chain-driven gravity energy storage system, characterized in that, Includes the following steps: S1. Real-time acquisition of active power data, flywheel speed, and truck data at the grid connection point of the chain-driven gravity energy storage system; S2. Based on the physical model of the chain-driven gravity energy storage system, the active power data, and the truck data, calculate the total fluctuation power prediction sequence; S3. Calculate the optimal flywheel speed sequence based on the flywheel speed and the total fluctuation power prediction sequence; S4. Control the flywheel energy storage device in the chain drive gravity energy storage system according to the optimal flywheel speed sequence, and output compensation power.

2. The power smoothing control method for a chain-driven gravity energy storage system according to claim 1, characterized in that, The calculation process of the total fluctuation power prediction sequence specifically includes: in, This represents the predicted total fluctuation power, which includes the superposition of multiple fluctuations. Indicates time, This indicates the total power measured at the grid connection point. This indicates the high-frequency power fluctuations caused by the polygonal effect in chain drives. This indicates the low-frequency step power fluctuation caused when a heavy-duty vehicle interacts with a slope. This represents the amplitude of the high-frequency frequency wave power. Indicates the frequency of high-frequency oscillations. Indicates phase, This represents the transmission efficiency coefficient. This indicates the overall mass of the truck. Represents gravitational acceleration. Indicates the linear velocity of the running line. Indicates the slope angle.

3. The power smoothing control method for a chain-driven gravity energy storage system according to claim 2, characterized in that, The objective function of the optimization model for calculating the optimal speed sequence of the flywheel is: ； in, For grid-connected power setting value, For prediction The flywheel compensation speed at any given moment, The ideal operating speed of the flywheel. express The theoretical compensation power of the flywheel at any given moment. express The theoretical compensation power of the flywheel at any given moment. These are the weighting coefficients for the power tracking term. The weight coefficient for the state penalty term. To control the coefficient of the action penalty term, To predict the step size.

4. The power smoothing control method for a chain-driven gravity energy storage system according to claim 3, characterized in that, The constraints of its optimization model include: Flywheel speed constraint: in, This is the lower limit of the flywheel speed. This is the upper limit of the flywheel speed; Flywheel power constraints: in, This represents the lower limit of flywheel energy storage capacity. This is the upper limit of flywheel energy storage capacity; Flywheel dynamics constraints: in, Let be the moment of inertia of the flywheel.

5. The power smoothing control method for a chain-driven gravity energy storage system according to claim 4, characterized in that, The flywheel operates under two different conditions based on the instantaneous power of the chain-driven gravity energy storage system, including: Energy release condition, at this time The flywheel decelerates and releases kinetic energy to compensate for the insufficient power of the chain drive's gravity-stored energy. Energy storage operating conditions, at this time The flywheel accelerates and absorbs kinetic energy, absorbing excess power stored in gravity by the chain drive. in, This indicates the actual compensation power of the flywheel.

6. The power smoothing control method for a chain-driven gravity energy storage system according to claim 1, characterized in that, Before the step of real-time acquisition of active power data, flywheel speed, and truck data at the grid-side connection point of the chain-driven gravity energy storage system, the following steps are also included: System initialization: Load the length, height, and angle of the chain drive ramp track, sprocket radius, number of sprocket teeth, overall mass of the truck, truck running linear velocity, flywheel moment of inertia, ideal operating point speed of the flywheel, flywheel speed range, flywheel power range, power tracking term weight coefficient, state penalty term weight coefficient, control action penalty term coefficient, prediction step size, control cycle, initial sprocket speed, initial number of trucks, and initial flywheel speed.

7. The power smoothing control method for a chain-driven gravity energy storage system according to claim 1, characterized in that, Also includes: Repeat steps S1-S4 to continuously update the output compensation power.

Images