Secondary frequency modulation method, device and equipment of hybrid energy storage system and medium

Abstract

The invention relates to the technical field of hybrid energy storage frequency modulation, and discloses a secondary frequency modulation method, device and equipment for a hybrid energy storage system and a medium, and the method comprises the steps: obtaining a power grid frequency deviation value, the real-time charge state of a short-time high-power energy storage system and the real-time charge state of a lithium battery energy storage system; determining an operation state interval of the hybrid energy storage system according to the real-time charge state of the short-time high-power energy storage system and the real-time charge state of the lithium battery energy storage system, determining a to-be-operated secondary frequency modulation strategy according to the power grid frequency deviation value, and calculating charging and discharging power parameters based on a preset formula, the secondary frequency modulation strategy to be operated is operated according to the operation state interval and the charging and discharging power parameters of the hybrid energy storage system, the occurrence of overcharging and overdischarging conditions can be avoided, and thus the service life of the energy storage system is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid energy storage frequency modulation, and particularly to a secondary frequency modulation method, device, equipment and medium for a hybrid energy storage system. Background Art

[0002] In the process of addressing climate change and promoting energy transformation, the large-scale access of renewable energy has become an inevitable trend of the times. However, the volatility and uncertainty of renewable energy have brought new challenges to the stable operation of the power system, especially the impact on the grid frequency stability. To effectively balance the mismatch between load and generation, energy storage technology has played a crucial role. Energy storage can not only achieve the spatio-temporal transfer of energy, but also provide necessary ancillary services for the power grid, such as frequency regulation and peak-valley optimization.

[0003] A single energy storage technology often has difficulty in meeting the requirements of multiple aspects such as power density, energy density, response speed, and cost-effectiveness. Therefore, the concept of a hybrid energy storage system has emerged. By organically integrating various energy storage technologies such as batteries, supercapacitors, and flywheels, it gives full play to their respective advantages and realizes more efficient and flexible energy management. Among many applications, frequency modulation services are particularly crucial, which are directly related to the stability and safety of the power system. Secondary frequency modulation refers to the process of further adjusting the output power of a generator set through an automatic generation control (AGC) system or manual operation by a dispatcher to restore the grid frequency to the rated value. When the grid frequency changes, the dispatching center obtains the frequency change information in real time through the monitoring system, and then sends adjustment instructions to the generator set according to the pre-set control strategy to increase or decrease its output power to restore frequency stability. The response speed of secondary frequency modulation is relatively slow, usually taking several minutes to dozens of minutes to complete the adjustment, but the adjustment accuracy is high, and it can restore the frequency to the rated value. The adjustment range of secondary frequency modulation is large, and it can cope with medium- and long-term, large load changes in the power grid. Currently, when providing grid secondary frequency modulation services, due to the lack of coordinated control of different energy storage systems, overcharging and over-discharging of the energy storage system will occur, which will seriously affect the life of the energy storage system and reduce the economy of the power station.

[0004] Therefore, there is an urgent need for a secondary frequency modulation method for a hybrid energy storage system to stabilize the output power of the hybrid energy storage, avoid overcharging and over-discharging of the energy storage system, and improve the service life of the energy storage. Summary of the Invention

[0005] In view of this, the present invention provides a secondary frequency modulation method, device, equipment and medium for a hybrid energy storage system to solve or partially solve the technical problem that the output power of the existing energy storage system is unstable and overcharging and over-discharging occur.

[0006] In a first aspect, the present invention provides a secondary frequency regulation method for a hybrid energy storage system. The hybrid energy storage system includes a short-term high-power energy storage system and a lithium-ion energy storage system, and the method includes: obtaining a power grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium-ion energy storage system; determining an operating state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium-ion energy storage system; determining a secondary frequency regulation strategy to be operated according to the power grid frequency deviation value, wherein the secondary frequency regulation strategy to be operated includes a secondary frequency regulation charging strategy and a secondary frequency regulation discharging strategy. If the power grid frequency deviation value is positive, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation charging strategy. If the power grid frequency deviation value is negative, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation discharging strategy; calculating charge and discharge power parameters based on a preset formula, and operating the secondary frequency regulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters.

[0007] Optionally, the secondary frequency regulation strategy to be operated includes a secondary frequency regulation charging strategy and a secondary frequency regulation discharging strategy; correspondingly, determining the secondary frequency regulation strategy to be operated according to the power grid frequency deviation value includes: if the power grid frequency deviation value is positive, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation charging strategy; if the power grid frequency deviation value is negative, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation discharging strategy.

[0008] Optionally, if the secondary frequency regulation strategy to be run is determined to be the secondary frequency regulation charging strategy, calculate the charge-discharge power parameters based on a preset formula, and run the secondary frequency regulation strategy to be run according to the operating state interval of the hybrid energy storage system and the charge-discharge power parameters, including: calculating the charge-discharge power parameters based on a preset formula, where the charge-discharge power parameters include the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system; if the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system is higher than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system and the state of charge of the short-term high-power energy storage system are both in the operating state interval of the shallow charge and shallow discharge region, then preferentially use the short-term high-power energy storage system for charging, compare the maximum charging power of the short-term high-power energy storage system with the grid requirement power value, and when the maximum charging power of the short-term high-power energy storage system is less than the grid requirement power value, use the lithium battery energy storage system to supplement the remaining charging demand; if the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system is lower than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system and the state of charge of the short-term high-power energy storage system are both in the deep charging region or the deep discharging region, then preferentially use the lithium battery energy storage system for charging, compare the maximum charging power of the lithium battery energy storage system with the grid requirement power value, and when the maximum charging power of the lithium battery energy storage system is less than the grid requirement power value, use the short-term high-power energy storage system to supplement the remaining charging demand.

[0009] Optionally, calculating the charge-discharge power parameters based on a preset formula includes: calculating the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system according to the following formula:

[0010]

[0011] In the formula, P cN，1 is the rated charging power of the short-term high-power energy storage system, n1 is a variable constant used to adjust the shape of the charging curve, P c，01 is used to limit the maximum power during the actual charging process of the short-term high-power energy storage system, SOC 1max is the maximum value of the state of charge set for the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, SOC 1high is the high warning level of the state of charge set for the short-term high-power energy storage system, P cN，2 is the rated charging power of the lithium battery energy storage system, P c，02 is used to limit the maximum power during the actual charging process of the lithium battery energy storage system, SOC 2max is the maximum value of the state of charge set for the lithium battery energy storage system, SOC2 is the real-time state of charge of the lithium battery energy storage system, SOC2high is the high warning level of the charge setting of the lithium - ion energy storage system, P c1，max is the maximum charging power of the short - term high - power energy storage system, P c2，max is the maximum charging power of the lithium - ion energy storage system.

[0012] Optionally, if the to - be - run secondary frequency regulation strategy is determined to be the secondary frequency regulation discharge strategy, calculate the charge - discharge power parameters based on a preset formula, and operate the to - be - run secondary frequency regulation strategy according to the operation state interval of the hybrid energy storage system and the charge - discharge power parameters, including: calculating the charge - discharge power parameters based on a preset formula, where the charge - discharge power parameters include the maximum discharge power of the short - term high - power energy storage system and the maximum discharge power of the lithium - ion energy storage system; if the operation state interval of the hybrid energy storage system is that the charge level of the lithium - ion energy storage system is lower than the operation state interval of the short - term high - power energy storage system, or the operation state interval of the hybrid energy storage system is that the charge levels of the lithium - ion energy storage system and the short - term high - power energy storage system are both in the shallow charge - discharge area operation state interval, then preferentially use the short - term high - power energy storage system for discharge, compare the maximum discharge power of the short - term high - power energy storage system with the grid - required power value, and when the maximum discharge power of the short - term high - power energy storage system is less than the grid - required power value, use the lithium - ion energy storage system to supplement the remaining discharge demand; if the operation state interval of the hybrid energy storage system is that the charge level of the lithium - ion energy storage system is higher than the operation state interval of the short - term high - power energy storage system, or the operation state interval of the hybrid energy storage system is that the charge levels of the lithium - ion energy storage system and the short - term high - power energy storage system are both in the deep - charge area or deep - discharge area operation state interval, then preferentially use the lithium - ion energy storage system for discharge, compare the maximum discharge power of the lithium - ion energy storage system with the grid - required power value, and when the maximum discharge power of the lithium - ion energy storage system is less than the grid - required power value, use the short - term high - power energy storage system to supplement the remaining discharge demand.

[0013] Optionally, calculating the charge - discharge power parameters based on a preset formula includes: calculating the maximum discharge power of the short - term high - power energy storage system and the maximum discharge power of the lithium - ion energy storage system according to the following formula:

[0014]

[0015] In the formula, P dN，1 is the rated discharge power of the short - term high - power energy storage system, n2 is a variable constant used to adjust the shape of the discharge curve, P d，01 is used to limit the maximum power during the actual discharge process of the short - term high - power energy storage system, SOC 1min is the minimum value of the charge setting of the short - term high - power energy storage system, SOC1 is the real - time charge state of the short - term high - power energy storage system, SOC 1low is the low warning level of the charge setting of the short - term high - power energy storage system, P dN，2is the rated discharge power of the lithium - ion energy storage system, P d，02 is used to limit the maximum power during the actual discharge process of the lithium - ion energy storage system, SOC 2min is the minimum value of the charge - of - state setting of the lithium - ion energy storage system, SOC2 is the real - time charge - of - state of the lithium - ion energy storage system, SOC 2low is the low warning level of the charge - of - state setting of the lithium - ion energy storage system, P d1，max is the maximum discharge power of the short - term high - power energy storage system, P d2，max is the maximum discharge power of the lithium - ion energy storage system.

[0016] In a second aspect, the present invention provides a secondary frequency regulation device for a hybrid energy storage system. The hybrid energy storage system includes a short - term high - power energy storage system and a lithium - ion energy storage system, and comprises: a power grid and energy storage parameter acquisition module, configured to acquire the power grid frequency deviation value, the real - time charge - of - state of the short - term high - power energy storage system, and the real - time charge - of - state of the lithium - ion energy storage system; an interval division module, configured to determine the operation state interval of the hybrid energy storage system according to the real - time charge - of - state of the short - term high - power energy storage system and the real - time charge - of - state of the lithium - ion energy storage system; an operation strategy determination module, configured to determine the secondary frequency regulation strategy to be operated according to the power grid frequency deviation value; and a strategy operation module, configured to calculate charge - discharge power parameters based on a preset formula, and operate the secondary frequency regulation strategy to be operated according to the operation state interval of the hybrid energy storage system and the charge - discharge power parameters.

[0017] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the secondary frequency regulation method of the hybrid energy storage system in the first aspect or any corresponding embodiment thereof.

[0018] In a fourth aspect, the present invention provides a computer - readable storage medium, on which computer instructions are stored. The computer instructions are used to cause a computer to execute the secondary frequency regulation method of the hybrid energy storage system in the first aspect or any corresponding embodiment thereof.

[0019] In a fifth aspect, the present invention provides a simulation system for the frequency regulation control strategy of a hybrid energy storage system, which is used to simulate and test the secondary frequency regulation method of the hybrid energy storage system in the first aspect or any corresponding embodiment thereof, including: a power grid simulation device, which is used to simulate the operation scenario of the power grid section; a hybrid energy storage unit, which is used to manage the charging and discharging and protection of the hybrid energy storage system; a hybrid energy storage frequency regulation simulation system, which is used to simulate the master station command trigger and its distribution mechanism of secondary frequency regulation by constructing a power grid power-frequency characteristic model and generating power disturbances and power deviations according to experimental settings, so as to realize the simulation and simulation process of secondary frequency regulation; a hybrid energy storage monitoring system, which is used to collect, monitor and protect the information of the devices of the hybrid energy storage unit; a hybrid energy storage energy management system, which is used to calculate the energy storage output command value in real time according to the secondary frequency regulation method of the hybrid energy storage system and issue it to the hybrid energy storage unit, so as to realize the rapid optimization operation of the secondary frequency regulation energy storage power; a frequency regulation performance evaluation system, which is used to evaluate and calculate the performance of the frequency regulation response of the hybrid energy storage system and evaluate the effectiveness of the secondary frequency regulation method of the hybrid energy storage system.

[0020] The present invention has the following beneficial effects:

[0021] For the secondary frequency regulation method, device, equipment and medium of the hybrid energy storage system of the present invention, by obtaining the power grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system, determining the operation state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system, determining the secondary frequency regulation strategy to be operated according to the power grid frequency deviation value, calculating the charge and discharge power parameters based on a preset formula, operating the secondary frequency regulation strategy to be operated according to the operation state interval of the hybrid energy storage system and the charge and discharge power parameters, and performing secondary frequency regulation by comprehensively considering the real-time state of charge of the short-term high-power energy storage system, the real-time state of charge of the lithium battery energy storage system and the power grid demand, avoiding frequency regulation by only considering a single energy storage, and the charge and discharge power parameters in the secondary frequency regulation process are calculated based on a preset formula, enabling it to charge and discharge smoothly, precisely controlling the hybrid energy storage system, making the output power of the hybrid energy storage system relatively stable, and avoiding overcharging and over-discharging, thereby improving the service life of the energy storage system. Description of the Drawings

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1Schematic flowchart of the secondary frequency regulation method for the hybrid energy storage system according to an embodiment of the present invention;

[0024] Figure 2 Block diagram of the structure of the frequency regulation control strategy simulation system for the hybrid energy storage system according to an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the simulation test results of the secondary frequency regulation method for the hybrid energy storage system according to an embodiment of the present invention;

[0026] Figure 4 Block diagram of the structure of the secondary frequency regulation device for the hybrid energy storage system according to an embodiment of the present invention;

[0027] Figure 5 Schematic diagram of the hardware structure of the computer device according to an embodiment of the present invention. Specific embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Developing an efficient hybrid energy storage frequency regulation strategy is a key part of advanced hybrid energy storage frequency regulation technology. Through intelligent decision-making and control, the frequency regulation strategy algorithm can ensure the optimal operation of energy storage components under various power market and grid conditions. In view of this, an embodiment of the present invention provides a secondary frequency regulation method for a hybrid energy storage system.

[0030] According to an embodiment of the present invention, an embodiment of a secondary frequency regulation method for a hybrid energy storage system is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0031] In this embodiment, a secondary frequency regulation method for a hybrid energy storage system is provided, which can be used in intelligent terminals such as computers.

[0032] The hybrid energy storage system includes a short-term high-power energy storage system and a lithium-ion energy storage system. Among them, the short-term high-power energy storage system can be a supercapacitor energy storage system or a flywheel energy storage system, and the lithium-ion energy storage system can be a lithium iron phosphate energy storage system.

[0033] Such as Figure 1As shown in the figure, the secondary frequency modulation method of the hybrid energy storage system according to the embodiment of the present invention includes the following steps:

[0034] Step S101, obtain the power grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium battery energy storage system.

[0035] Specifically, a frequency modulation dead zone for the short-term high-power energy storage system and the lithium battery energy storage system is preset in advance, and the power grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium battery energy storage system are collected through a collection device.

[0036] Step S102, determine the operation state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system.

[0037] Specifically, set the minimum value of the state of charge setting of the short-term high-power energy storage system SOC 1min , the low warning level of the state of charge setting of the short-term high-power energy storage system SOC 1low , the high warning level of the state of charge setting of the short-term high-power energy storage system SOC 1high , the maximum value of the state of charge setting of the short-term high-power energy storage system SOC 1max ; set the minimum value of the state of charge setting of the lithium battery energy storage system SOC 2min , the low warning level of the state of charge setting of the lithium battery energy storage system SOC 2low , the high warning level of the state of charge setting of the lithium battery energy storage system SOC 2high , the maximum value of the state of charge setting of the lithium battery energy storage system SOC 2max .

[0038] According to the relationship between the real-time state of charge SOC1 of the short-term high-power energy storage system and the real-time state of charge SOC2 of the lithium battery energy storage system relative to the above set values, the operation state interval of the hybrid energy storage system is divided into nine types, namely S1-S9.

[0039] Table 1 Schematic diagram of the division of the operation state interval of the hybrid energy storage system

[0040]

[0041] The operating state intervals of the hybrid energy storage system are divided as shown in Table 1. Among them, in the operating state intervals S2, S3, and S6, the state of charge of the lithium-ion energy storage system is higher than that of the short-term high-power energy storage system. In the operating state intervals S1, S5, and S9, the state of charge of the lithium-ion energy storage system is the same as that of the short-term high-power energy storage system. In the operating state intervals S4, S7, and S8, the state of charge of the lithium-ion energy storage system is lower than that of the short-term high-power energy storage system. In the operating state interval S5, the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the shallow charge and discharge region. In the operating state intervals S1 and S9, the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the deep charge region or the deep discharge region.

[0042] Step S103: Determine the secondary frequency regulation strategy to be operated according to the power grid frequency deviation value.

[0043] Specifically, the secondary frequency regulation strategy to be operated includes a secondary frequency regulation charging strategy and a secondary frequency regulation discharging strategy. If the power grid frequency deviation value is positive, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation charging strategy; if the power grid frequency deviation value is negative, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation discharging strategy.

[0044] Through the above method, the secondary frequency regulation strategy can be confirmed according to the power grid demand and the real-time state of the hybrid energy storage system, which can reduce the risk of overcharging and over-discharging of the energy storage system while meeting the power grid frequency regulation demand.

[0045] Step S104: Calculate the charge and discharge power parameters based on a preset formula, and operate the secondary frequency regulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters.

[0046] Specifically, the preset formula is obtained by fitting based on an S-shaped curve similar to population growth, combining the parameters of the short-term high-power energy storage system, and adding parameters to adjust the shape of the charging curve. The charge and discharge power parameters are calculated through the preset formula. When any energy storage system in the hybrid energy storage system has the minimum state of charge, it will charge based on the charge and discharge power parameters. As the state of charge increases, the charge and discharge power parameters decrease smoothly. When the state of charge exceeds the maximum value, the charge and discharge power parameters do not charge. When the energy storage system has the maximum state of charge, it will discharge with the charge and discharge power parameters. As the state of charge decreases, the charge and discharge power parameters decrease smoothly. When the state of charge exceeds the minimum value, the energy storage system does not discharge. This can effectively avoid the occurrence of overcharging and over-discharging of the energy storage system and improve the service life of the energy storage.

[0047] The secondary frequency regulation method of the hybrid energy storage system according to the embodiment of the present invention obtains the grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium battery energy storage system, determines the operating state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system, determines the secondary frequency regulation strategy to be operated according to the grid frequency deviation value, calculates the charge and discharge power parameters based on a preset formula, operates the secondary frequency regulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters, and performs secondary frequency regulation by comprehensively considering the real-time state of charge of the short-term high-power energy storage system, the real-time state of charge of the lithium battery energy storage system, and the grid demand, avoiding frequency regulation by only considering a single energy storage, and the charge and discharge power parameters during the secondary frequency regulation process are obtained by calculation based on a preset formula, enabling smooth charge and discharge, precisely controlling the hybrid energy storage system, making the output power of the hybrid energy storage system relatively stable, avoiding overcharging and over-discharging, and thus improving the service life of the energy storage system.

[0048] In some embodiments, the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation charging strategy. Correspondingly, in step S104, calculating the charge and discharge power parameters based on a preset formula and operating the secondary frequency regulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters includes:

[0049] Step S10411, calculating the charge and discharge power parameters based on a preset formula, where the charge and discharge power parameters include the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system.

[0050] Specifically, the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system are calculated according to the following formula:

[0051]

[0052] In the formula, P cN，1 is the rated charging power of the short-term high-power energy storage system, n1 is a variable constant used to adjust the shape of the charging curve, P c，01 is used to limit the maximum power during the actual charging process of the short-term high-power energy storage system, SOC 1max is the maximum value of the state of charge set for the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, SOC 1high is the high warning level of the state of charge set for the short-term high-power energy storage system, P cN，2 is the rated charging power of the lithium battery energy storage system, P c，02 is used to limit the maximum power during the actual charging process of the lithium battery energy storage system, SOC 2max is the maximum value of the state of charge set for the lithium battery energy storage system, SOC2 is the real-time state of charge of the lithium battery energy storage system, SOC2high is the high warning level for the charge setting of the lithium - ion energy storage system, P c1，max is the maximum charging power of the short - term high - power energy storage system, P c2，max is the maximum charging power of the lithium - ion energy storage system.

[0053] In the embodiments of the present invention, the parameters of the corresponding energy storage system are combined, and parameters for adjusting the charging curve shape are added to construct a calculation formula for the maximum charging power. By calculating the maximum charging power of the short - term high - power energy storage system and the maximum charging power of the lithium - ion energy storage system through the above formula, when the hybrid energy storage system operates the secondary frequency modulation charging strategy, any energy storage system in the hybrid energy storage system will charge at the maximum charging power when the state of charge is the smallest. As the state of charge increases, the charge - discharge power parameter smoothly decreases. When the state of charge exceeds the maximum value, the charge - discharge power parameter does not charge. This can effectively avoid the occurrence of over - charging and over - discharging of the energy storage system and improve the service life of the energy storage.

[0054] Step S10412, if the operating state interval of the hybrid energy storage system is such that the charge level of the lithium - ion energy storage system is higher than the operating state interval of the short - term high - power energy storage system, or the operating state interval of the hybrid energy storage system is such that the charge levels of both the lithium - ion energy storage system and the short - term high - power energy storage system are in the operating state interval of the shallow charge and shallow discharge region, then the short - term high - power energy storage system is preferentially used for charging. The maximum charging power of the short - term high - power energy storage system is compared with the power value required by the power grid. When the maximum charging power of the short - term high - power energy storage system is less than the power value required by the power grid, the lithium - ion energy storage system is used to supplement the remaining charging demand.

[0055] Specifically, in the operating state intervals S2, S3, S5, and S6, the short - term high - power energy storage system is preferentially used for charging, and the charging power is P c1 , if the short - term high - power energy storage system cannot meet the power grid demand, then the lithium - ion energy storage system is used to supplement the remaining charging demand, and the charging power is P c2 , and the charging strategy is expressed as:

[0056]

[0057] In the formula, ΔP is the power value required by the power grid.

[0058] In operating state intervals S2, S3, and S6, the charge level of the lithium-ion energy storage system is higher than that of the short-term high-power energy storage system. During charging, the short-term high-power energy storage system is prioritized to return its charge level to the shallow charge and discharge region, and the lithium-ion energy storage system is charged with the remaining component of the power value required by the grid in the winning frequency regulation instruction. In operating state interval S5, the charge levels of the lithium-ion energy storage system and the short-term high-power energy storage system are both in the shallow charge and discharge region. At this time, the hybrid energy storage system has the largest charge and discharge capacity that can be declared, and can obtain more benefits in the frequency regulation market. This is the ideal operating state for the hybrid energy storage system to obtain more frequency regulation benefits. At this time, the short-term high-power energy storage system undertakes more frequent and in-depth secondary frequency regulation tasks, while adjusting the charge level of the lithium-ion energy storage system to the shallow charge and discharge working region. This can improve the working environment of the lithium-ion energy storage system and extend the overall life cycle of the hybrid energy storage system.

[0059] In step S10413, if the operating state interval of the hybrid energy storage system is such that the charge level of the lithium energy storage system is lower than the operating state interval of the short-term high-power energy storage system, or if the operating state interval of the hybrid energy storage system is such that the charge level of the lithium energy storage system and the charge level of the short-term high-power energy storage system are both in the deep charge area or the deep discharge area, the lithium energy storage system is preferentially used for charging, and the maximum charging power of the lithium energy storage system is compared with the power value required by the power grid. When the maximum charging power of the lithium energy storage system is less than the power value required by the power grid, the short-term high-power energy storage system is used to make up for the remaining charging demand.

[0060] Specifically, in the operating state intervals S1, S4, S7, S8 and S9, the lithium battery energy storage system is charged first, and the charging power is P c2 If the grid demand cannot be met, the short-term high-power energy storage system will continue to make up for the remaining charging demand, and the charging power is P c1 The charging strategy is expressed as:

[0061]

[0062] In operating state intervals S4, S7, and S8, the charge level of the lithium-ion energy storage system is lower than that of the short-term high-power energy storage system. A strategy is adopted in which the lithium-ion energy storage system is prioritized for charging, while the short-term high-power energy storage system fills the remaining charging demand. In states S1 and S9, the charge levels of the short-term high-power energy storage system and the lithium-ion energy storage system are both in the deep charge or deep discharge zone. In this state, the maximum charge and discharge power of the short-term high-power energy storage system and the lithium-ion energy storage system are strictly limited to prevent overcharge and over-discharge. In this state, prioritizing the charging or discharging of the lithium-ion battery can remove its charge level from the deep charge and discharge state, thereby improving the working environment of the lithium-ion battery and extending the overall life cycle of the hybrid energy storage system.

[0063] According to an embodiment of the present invention, during operating states S2, S3, and S6, the lithium energy storage system has a higher charge level than the short-term high-power energy storage system. The secondary frequency regulation charging strategy prioritizes charging the short-term high-power energy storage system, with the lithium energy storage system filling any remaining charge demand. This leverages the short-term high-power energy storage system's advantage of unlimited charge and discharge cycles and ensures the lithium energy storage system maintains a certain level of regulation capability within the next time period. In state S5, both the lithium energy storage system and the short-term high-power energy storage system are within the shallow charge and discharge range. The secondary frequency regulation charging strategy similarly prioritizes charging the short-term high-power energy storage system, with the lithium energy storage system filling any remaining charge demand. At this point, the hybrid energy storage system has the highest applicable charge and discharge capacity, potentially generating greater revenue in the frequency regulation market. This ideal operating state for the hybrid energy storage system, where frequency regulation revenue is maximized when frequency regulation demand is uncertain, allows the short-term high-power energy storage system to assume more frequent and intensive frequency regulation duties, improves the lithium battery's operating environment, and extends the overall lifecycle of the hybrid energy storage system.

[0064] In operating state intervals S4, S7, and S8, the charge level of the short-term high-power energy storage system is higher than that of the lithium-ion energy storage system. The secondary frequency regulation charging strategy prioritizes charging the lithium-ion energy storage system, with the short-term high-power energy storage system filling the remaining charge demand. This fully utilizes the large storage capacity of lithium batteries as energy storage elements, while also allowing the short-term high-power energy storage system to retain a certain amount of charging capacity in preparation for the next regulation task. In operating state intervals S1 and S9, the charge levels of both the lithium-ion energy storage system and the short-term high-power energy storage system are in the deep charge or deep discharge region. In this state, the maximum charge and discharge power of the short-term high-power energy storage system and the lithium-ion energy storage system are strictly limited to prevent overcharge and over-discharge. In this state, prioritizing the charging of the lithium-ion energy storage system can remove its charge level from the deep charge and discharge state, improve the working environment of the lithium battery, and extend the overall life cycle of the hybrid energy storage system.

[0065] In some embodiments, the secondary frequency modulation strategy to be executed is determined to be a secondary frequency modulation discharge strategy. Correspondingly, step S104 calculates the charge and discharge power parameters based on a preset formula, and executes the secondary frequency modulation strategy to be executed according to the operating state range of the hybrid energy storage system and the charge and discharge power parameters, including:

[0066] Step S10421 , calculating the charge and discharge power parameters based on a preset formula, wherein the charge and discharge power parameters include the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium battery energy storage system.

[0067] Specifically, the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium battery energy storage system are calculated according to the following formula:

[0068]

[0069] In the formula, P dN，1 is the rated discharge power of the short-term high-power energy storage system, n2 is a variable constant used to adjust the shape of the discharge curve, and P d，01 is used to limit the maximum power during the actual discharge process of the short-term high-power energy storage system, and SOC 1min is the minimum value of the charge setting of the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, and SOC 1low is the low warning level of the charge setting of the short-term high-power energy storage system, and P dN，2 is the rated discharge power of the lithium-ion energy storage system, and P d，02 is used to limit the maximum power during the actual discharge process of the lithium-ion energy storage system, and SOC 2min is the minimum value of the charge setting of the lithium-ion energy storage system, SOC2 is the real-time state of charge of the lithium-ion energy storage system, and SOC 2low is the low warning level of the charge setting of the lithium-ion energy storage system, and P d1，max is the maximum discharge power of the short-term high-power energy storage system, and P d2，max is the maximum discharge power of the lithium-ion energy storage system.

[0070] In the embodiment of the present invention, the parameters of the corresponding energy storage system are combined, and parameters for adjusting the shape of the discharge curve are added to construct a calculation formula for the maximum discharge power.

[0071] The maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium-ion energy storage system are calculated through the above formula. When the hybrid energy storage system operates the secondary frequency modulation discharge strategy, any energy storage system in the hybrid energy storage system will discharge at the maximum discharge power when the state of charge is the largest. As the state of charge decreases, the maximum discharge power decreases smoothly. When the state of charge exceeds the minimum value, the energy storage system does not discharge. This can effectively avoid the occurrence of overcharging and over-discharging of the energy storage system and improve the service life of the energy storage.

[0072] Step S10422, if the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system is lower than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system and the state of charge of the short-term high-power energy storage system are both in the operating state interval of the shallow charge and shallow discharge area, the short-term high-power energy storage system is preferentially used for discharge. The maximum discharge power of the short-term high-power energy storage system is compared with the power value required by the power grid. When the maximum discharge power of the short-term high-power energy storage system is less than the power value required by the power grid, the lithium-ion energy storage system is used to supplement the remaining discharge demand.

[0073] Specifically, when the operating state intervals are S4, S5, S7, and S8, a strategy of preferentially discharging the short-term high-power energy storage system and using the lithium-ion energy storage to supplement the remaining discharge demand is adopted. The short-term high-power energy storage system discharges preferentially with a discharge power of P d1 , if the power value ΔP required by the power grid cannot be met, the lithium-ion energy storage system continues to supplement the remaining discharge with a discharge power of P d2 , and the discharge strategy is as follows:

[0074]

[0075] When the operating state intervals are S4, S7, and S8, the state of charge of the short-term high-power energy storage system is higher than that of the lithium-ion energy storage system. The secondary frequency modulation charging strategy adopts the short-term high-power energy storage system to discharge preferentially, and the lithium-ion energy storage system supplements the remaining discharge demand, making full use of the advantage that the short-term high-power energy storage system has no limit on the number of charge and discharge cycles, and can ensure that the lithium-ion energy storage system has a certain adjustment ability in the next time period.

[0076] In the operating state interval of S5, the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the shallow charge and discharge area. The secondary frequency modulation charging strategy also adopts the short-term high-power energy storage system to discharge preferentially, and the lithium-ion energy storage system supplements the remaining discharge demand. At this time, the charge and discharge capacity that the hybrid energy storage system can declare is the largest, and more benefits can be obtained in the frequency modulation market. This makes the hybrid energy storage system in the most ideal working state to obtain more frequency modulation benefits when the direction of the unknown frequency modulation demand. The short-term high-power energy storage system undertakes more frequent and deep frequency modulation tasks at this time, which can improve the working environment of the lithium battery to extend the overall life cycle of the hybrid energy storage system.

[0077] Step S10423, if the operating state interval of the hybrid energy storage system is such that the state of charge of the lithium-ion energy storage system is higher than that of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is such that the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the deep charge area or the deep discharge area, then the lithium-ion energy storage system is preferentially used for discharging, and the maximum discharge power of the lithium-ion energy storage system is compared with the power value required by the power grid. When the maximum discharge power of the lithium-ion energy storage system is less than the power value required by the power grid, the short-term high-power energy storage system is used to supplement the remaining discharge demand.

[0078] Specifically, when the operating state intervals are S1, S2, S3, S6, and S9, a strategy of preferentially discharging the lithium-ion energy storage system and using the short-term high-power energy storage system to supplement the remaining discharge demand is adopted. The lithium-ion energy storage system discharges preferentially with a discharge power of P d2 , if the power value ΔP required by the power grid cannot be met, the short-term high-power energy storage system continues to supplement the remaining discharge with a discharge power of P d1 , and the discharge strategy is as follows:

[0079]

[0080] When operating in the S2, S3, and S6 ranges, the lithium-ion energy storage system has a higher charge level than the short-term, high-power energy storage system. The secondary frequency regulation charging strategy prioritizes discharge of the lithium-ion energy storage system, with the short-term, high-power energy storage system providing the remaining discharge. This strategy leverages the large storage capacity of lithium-ion batteries as energy storage components, while also allowing the short-term, high-power energy storage system to retain a certain amount of charge capacity for the next regulation period.

[0081] When the operating status range is S1 and S9, the charge level of the lithium battery energy storage system and the charge level of the short-term high-power energy storage system are both in the deep charge area or deep discharge area. In this state, the maximum charge and discharge power of the short-term high-power energy storage system and the lithium battery energy storage system will be strictly limited to avoid overcharge and over-discharge. In this state, the lithium battery energy storage system is discharged first to remove its charge level from the deep charge and discharge state, which can improve the working environment of the lithium battery and extend the overall life cycle of the hybrid energy storage system.

[0082] In order to develop, test and verify the hybrid energy storage frequency regulation strategy algorithm, it is necessary to develop a hybrid energy storage frequency regulation control strategy simulation system to conduct detailed scenario simulation and performance testing to evaluate the performance of the algorithm in frequency regulation.

[0083] In view of this, a hybrid energy storage system frequency regulation control strategy simulation system according to an embodiment of the present invention is used to simulate and test the secondary frequency regulation method of the hybrid energy storage system in the above embodiment. Figure 2 As shown, the hybrid energy storage system frequency regulation control strategy simulation system includes:

[0084] Grid simulation device, used to simulate the operation scenarios of grid segments;

[0085] Hybrid energy storage unit, used for charge and discharge management and protection of the hybrid energy storage system;

[0086] The hybrid energy storage frequency regulation simulation system is used to build a power-frequency characteristic model of the power grid, generate power disturbances and power deviations according to the experimental settings, simulate the master station command triggering and distribution mechanism of secondary frequency regulation, and realize the simulation and emulation process of secondary frequency regulation;

[0087] Hybrid energy storage monitoring system, used for equipment information collection, monitoring and protection of hybrid energy storage units;

[0088] The hybrid energy storage energy management system is used to calculate the energy storage output command value in real time based on the secondary frequency regulation method of the hybrid energy storage system and issue it to the hybrid energy storage unit, realizing rapid optimization calculation of the secondary frequency regulation energy storage power;

[0089] A frequency modulation performance evaluation system is used to evaluate and calculate the frequency modulation response performance of a hybrid energy storage system, and to evaluate the effectiveness of the secondary frequency modulation method of the hybrid energy storage system.

[0090] Specifically, the power of the power grid simulation device is 60 kVA. It can simulate typical operating scenarios such as frequency changes and voltage changes at the power grid end, isolate the impact on the main grid, and perform power exchange. As the excitation source of the simulation system, the power grid simulator can adjust the output frequency and output amplitude according to the instructions issued by the system software, and is the frequency modulation starting point of the simulation test system.

[0091] The hybrid energy storage unit is used to realize the charge and discharge management and protection of the energy storage unit, etc., including two bidirectional inverters (PCS), a supercapacitor battery system / lithium iron phosphate battery system, a supercapacitor management system (CMS), a battery management system (BMS), a battery cabinet, a supercapacitor cabinet, etc. The power grid simulator supplies power to the two PCSs respectively through the power distribution cabinet. The rated power of the two PCSs is 30 kW each, and the DC side voltage range is (150 - 750) V, which are respectively connected to the supercapacitor battery module and the lithium iron phosphate battery module. The supercapacitor system is composed of 8 sets of 105V 94.4F modules connected in series; the lithium iron phosphate battery system is composed of 6 modules connected in series, and each module is composed of 24 120Ah, 3.2V battery cells connected in series. The CMS and BMS mainly include information such as voltage, current, temperature acquisition, capacity diagnosis SOC, state of health estimation SOH, and monomer balance maintenance of supercapacitors and batteries.

[0092] The hybrid energy storage frequency modulation simulation system obtains changes in the frequency, power, etc. of the power grid simulator through high-frequency acquisition devices, combines information such as PCS, CMS, and BMS, constructs a power grid power-frequency characteristic model, generates power disturbances and power deviations according to experimental settings, and simulates secondary frequency modulation, the triggering and distribution mechanism of the master station command for secondary frequency modulation, etc., to realize the simulation and simulation process of secondary frequency modulation, and is the power grid frequency source and secondary frequency modulation AGC command source of the entire simulation system.

[0093] The hybrid energy storage monitoring system is used to realize functions such as information acquisition, monitoring, and protection of equipment such as the management system and bidirectional inverters of the hybrid energy storage unit.

[0094] The hybrid energy storage energy management system collects and manages all battery management system data, energy storage converter data, and main primary / secondary electrical equipment data from the hybrid energy storage monitoring system, combines information such as PCS and the energy storage SOC state, and runs the hybrid energy storage frequency modulation strategy in real time, calculates the energy storage output command value, and issues it to the energy storage PCS to realize the rapid optimization operation of secondary frequency modulation or secondary frequency modulation energy storage power.

[0095] The frequency modulation performance evaluation system calculates the performance evaluation of the secondary frequency modulation and secondary frequency modulation response of the hybrid energy storage system. For secondary frequency modulation, based on the recorded grid frequency, the output power of the hybrid energy storage, and the SOC of each energy storage unit, the maximum frequency deviation, the maximum frequency change rate, the stabilization time, the steady-state frequency, the response time, the load adjustment range, the adjustment range deviation, the power contribution index, the response time qualification rate, the load adjustment range qualification rate, the adjustment range deviation qualification rate, the power contribution index qualification rate, and the secondary frequency modulation qualification rate are calculated. For secondary frequency modulation, based on the recorded AGC command, the output power of the hybrid energy storage, and the SOC of each energy storage unit, the Kp value and the frequency modulation mileage of the secondary frequency modulation are calculated, and the energy consumption, cost, and revenue of the secondary frequency modulation are calculated.

[0096] The test functions of the hybrid energy storage system frequency modulation control strategy simulation system include:

[0097] (1) Electrical protection test: including anti-islanding effect, over- and under-voltage protection, and over- and under-frequency protection, etc.

[0098] (2) DC characteristic test: including regulated voltage accuracy, regulated current accuracy, efficiency test, voltage limit characteristic, current limit characteristic, constant power characteristic, ripple factor, input and output over- and under-voltage alarm protection experiment, reverse connection protection test, short-circuit protection test, and soft start performance test.

[0099] (3) Performance test of BMS: including voltage accuracy, current accuracy, and protection function.

[0100] (4) Charge and discharge conversion efficiency test of the energy storage converter.

[0101] (5) Charge and discharge capacity and efficiency test of the energy storage system (DC side).

[0102] (6) Charge and discharge capacity and efficiency test of the energy storage system (AC side).

[0103] (7) Secondary frequency modulation response time, response accuracy, and response speed test of the energy storage system: including secondary frequency modulation start time, end time, theoretical integral power, actual integral power, speed regulation rate, maximum adjustment range, theoretical adjustment range, maximum frequency deviation, maximum frequency change rate, stabilization time, steady-state frequency, response time, load adjustment range, adjustment range deviation, power contribution index, response time qualification rate, load adjustment range qualification rate, adjustment range deviation qualification rate, power contribution index qualification rate, and secondary frequency modulation qualification rate.

[0104] (8) Secondary frequency modulation response time, response accuracy, and response speed test of the energy storage system: including AGC order time, end time, response time, theoretical action power, actual action power, regulation rate, switch-on and switch-off record, regulation accuracy, and available time.

[0105] (9) Coordinated control test of primary and secondary frequency regulation for energy storage system: including the test of AGC locked by secondary frequency regulation.

[0106] (10) Overload capacity test of energy storage system.

[0107] (11) Test of start-up and shutdown response time of energy storage system.

[0108] The simulation system of the frequency regulation control strategy for the hybrid energy storage system adopts the coupling method of physical simulation and digital simulation, incorporating non-ideal factors in actual operation, such as environmental temperature changes and actual conversion efficiency fluctuations, into the simulation evaluation process, making the simulation, test, and evaluation results of the control strategy of the energy management system under typical scenarios of primary and secondary frequency regulation closer to the actual working conditions, ensuring that the timing performance changes of the control strategy under different grid frequencies, automatic generation control signals, and energy storage configurations are similar to those in actual station deployment, and improving the adaptability and effectiveness of the control strategy after implementation.

[0109] Figure 3 It is a schematic diagram of the result of simulating and testing the secondary frequency regulation method of the hybrid energy storage system in the above embodiment by the simulation system of the frequency regulation control strategy for the hybrid energy storage system. Among them, the short-term high-power energy storage system adopts the supercapacitor energy storage system, and the lithium-ion energy storage system adopts the lithium iron phosphate energy storage system. The experimental results of secondary frequency regulation performance show that this strategy algorithm can respond well to the AGC command in the secondary frequency regulation performance test, with rapid response, stable output, and excellent performance.

[0110] The embodiment of the present invention also provides a secondary frequency regulation device for a hybrid energy storage system. The hybrid energy storage system includes a short-term high-power energy storage system and a lithium-ion energy storage system. As Figure 4 shown, the secondary frequency regulation device of the hybrid energy storage system includes:

[0111] Grid and energy storage parameter acquisition module 401, used to acquire the grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium-ion energy storage system;

[0112] Interval division module 402, used to determine the operation state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium-ion energy storage system;

[0113] Operation strategy determination module 403, used to determine the secondary frequency regulation strategy to be operated according to the grid frequency deviation value;

[0114] Strategy operation module 404, used to calculate the charge and discharge power parameters based on a preset formula, and operate the secondary frequency regulation strategy to be operated according to the operation state interval of the hybrid energy storage system and the charge and discharge power parameters.

[0115] The secondary frequency regulation device of the hybrid energy storage system according to the embodiment of the present invention obtains the power grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium battery energy storage system, determines the operating state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system, determines the secondary frequency regulation strategy to be operated according to the power grid frequency deviation value, calculates the charge and discharge power parameters based on a preset formula, and operates the secondary frequency regulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters, and performs secondary frequency regulation by comprehensively considering the real-time state of charge of the short-term high-power energy storage system, the real-time state of charge of the lithium battery energy storage system, and the power grid demand, avoiding frequency regulation by only considering a single energy storage, and the charge and discharge power parameters during the secondary frequency regulation process are obtained by calculation based on a preset formula, enabling it to charge and discharge smoothly, precisely controlling the hybrid energy storage system, making the output power of the hybrid energy storage system relatively stable, and avoiding overcharging and over-discharging situations, thereby improving the service life of the energy storage system.

[0116] Further, the secondary frequency regulation strategy to be operated includes a secondary frequency regulation charging strategy and a secondary frequency regulation discharging strategy;

[0117] Correspondingly, the operation strategy determination module 403 includes:

[0118] The secondary frequency regulation charging strategy determination module is used to determine the secondary frequency regulation strategy to be operated as the secondary frequency regulation charging strategy if the power grid frequency deviation value is positive;

[0119] The secondary frequency regulation discharging strategy determination module is used to determine the secondary frequency regulation strategy to be operated as the secondary frequency regulation discharging strategy if the power grid frequency deviation value is negative.

[0120] Further, if the secondary frequency regulation strategy to be operated is determined as the secondary frequency regulation charging strategy, the strategy operation module 404 includes:

[0121] The charging parameter calculation module is used to calculate the charge and discharge power parameters based on a preset formula, where the charge and discharge power parameters include the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system;

[0122] The first charging strategy module is used to preferentially charge the short-term high-power energy storage system if the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system is higher than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system and the state of charge of the short-term high-power energy storage system are both in the operating state interval of the shallow charge and discharge area, compare the maximum charging power of the short-term high-power energy storage system with the power grid required power value, and when the maximum charging power of the short-term high-power energy storage system is less than the power grid required power value, use the lithium battery energy storage system to supplement the remaining charging demand;

[0123] The second charging strategy module is used to, if the operating state range of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system is lower than the operating state range of the short-term high-power energy storage system, or the operating state range of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system and the state of charge of the short-term high-power energy storage system are both in the deep charging area or the deep discharging area, preferentially use the lithium-ion energy storage system for charging, compare the maximum charging power of the lithium-ion energy storage system with the grid requirement power value, and when the maximum charging power of the lithium-ion energy storage system is less than the grid requirement power value, use the short-term high-power energy storage system to supplement the remaining charging demand.

[0124] Furthermore, the charging parameter calculation module is also used for:

[0125] Calculating the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium-ion energy storage system according to the following formula:

[0126]

[0127] In the formula, P cN，1 is the rated charging power of the short-term high-power energy storage system, n1 is a variable constant used to adjust the shape of the charging curve, P c，01 is used to limit the maximum power during the actual charging process of the short-term high-power energy storage system, SOC 1max is the maximum value of the state of charge set for the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, SOC 1high is the high warning level of the state of charge set for the short-term high-power energy storage system, P cN，2 is the rated charging power of the lithium-ion energy storage system, P c，02 is used to limit the maximum power during the actual charging process of the lithium-ion energy storage system, SOC 2max is the maximum value of the state of charge set for the lithium-ion energy storage system, SOC2 is the real-time state of charge of the lithium-ion energy storage system, SOC 2high is the high warning level of the state of charge set for the lithium-ion energy storage system, P c1，max is the maximum charging power of the short-term high-power energy storage system, P c2，max is the maximum charging power of the lithium-ion energy storage system.

[0128] Furthermore, if the secondary frequency regulation strategy to be run is determined to be the secondary frequency regulation discharge strategy, the strategy operation module 404 includes:

[0129] A discharge parameter calculation module, which is used to calculate charge-discharge power parameters based on a preset formula, where the charge-discharge power parameters include the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium-ion energy storage system;

[0130] The first discharge strategy module is used to preferentially use the short-term high-power energy storage system for discharging if the operating state range of the hybrid energy storage system is such that the state of charge of the lithium-ion energy storage system is lower than the operating state range of the short-term high-power energy storage system, or if the operating state range of the hybrid energy storage system is such that the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the shallow charge and discharge region. Compare the maximum discharge power of the short-term high-power energy storage system with the grid required power value. When the maximum discharge power of the short-term high-power energy storage system is less than the grid required power value, use the lithium-ion energy storage system to supplement the remaining discharge demand;

[0131] The second discharge strategy module is used to preferentially use the lithium-ion energy storage system for discharging if the operating state range of the hybrid energy storage system is such that the state of charge of the lithium-ion energy storage system is higher than the operating state range of the short-term high-power energy storage system, or if the operating state range of the hybrid energy storage system is such that the state of charge of both the lithium-ion energy storage system and the short-term high-power energy storage system is in the deep charge region or the deep discharge region. Compare the maximum discharge power of the lithium-ion energy storage system with the grid required power value. When the maximum discharge power of the lithium-ion energy storage system is less than the grid required power value, use the short-term high-power energy storage system to supplement the remaining discharge demand.

[0132] Furthermore, the discharge parameter calculation module is also used for:

[0133] Calculate the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium-ion energy storage system according to the following formula:

[0134]

[0135] where P dN，1 is the rated discharge power of the short-term high-power energy storage system, n2 is a variable constant used to adjust the shape of the discharge curve, P d，01 is used to limit the maximum power during the actual discharge process of the short-term high-power energy storage system, SOC 1min is the minimum value of the state of charge set for the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, SOC 1low is the low warning level of the state of charge set for the short-term high-power energy storage system, P dN，2 is the rated discharge power of the lithium-ion energy storage system, P d，02 is used to limit the maximum power during the actual discharge process of the lithium-ion energy storage system, SOC 2min is the minimum value of the state of charge set for the lithium-ion energy storage system, SOC2 is the real-time state of charge of the lithium-ion energy storage system, SOC 2low is the low warning level of the state of charge set for the lithium-ion energy storage system, P d1,max is the maximum discharge power of the short-term high-power energy storage system, P d2,maxIt is the maximum discharge power of the lithium battery energy storage system.

[0136] The embodiment of the present invention also provides a structural schematic diagram of a computer device, as Figure 5 shown. The computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Each component communicates with each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (such as a server array, a set of blade servers, or a multi-processor system). Figure 5 In the figure, one processor 10 is taken as an example.

[0137] The processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, the processor 10 can further include a hardware chip. The above-mentioned hardware chip can be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The above-mentioned programmable logic device can be a complex programmable logic device, a field-programmable gate array, a general array logic, or any combination thereof.

[0138] Among them, the memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0139] The memory 20 can include a storage program area and a storage data area. Among them, the storage program area can store an operating system and application programs required for at least one function; the storage data area can store data created according to the use of the computer device. In addition, the memory 20 can include high-speed random access memory, and can also include non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 can optionally include a memory remotely set relative to the processor 10, and these remote memories can be connected to the computer device through a network. Examples of the above-mentioned network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and a combination thereof.

[0140] The memory 20 can include volatile memory, such as random access memory; the memory can also include non-volatile memory, such as flash memory, a hard disk, or a solid-state drive; the memory 20 can also include a combination of the above types of memory.

[0141] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30, and the output device 40 may be connected through a bus or other means. Figure 5 Taking connection through a bus as an example.

[0142] The input device 30 can receive input digital or character information, and generate key signal inputs related to the user settings and function controls of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touchpad, a pointing stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED), and a haptic feedback device (e.g., a vibration motor), etc. The above display device includes but is not limited to a liquid crystal display, a light-emitting diode, a display, and a plasma display. In some alternative embodiments, the display device may be a touch screen.

[0143] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented by downloading through a network and originally stored in a remote storage medium or a non-transitory machine-readable storage medium and will be stored in a local storage medium, so that the method described herein can be processed by such software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium may be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium may also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method shown in the above embodiment is implemented.

[0144] A part of the present invention can be applied as a computer program product, such as computer program instructions. When executed by a computer, through the operation of the computer, the methods and / or technical solutions according to the present invention can be called or provided. Those skilled in the art should be able to understand that the forms of existence of computer program instructions in a computer-readable medium include but are not limited to source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include but are not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible by the computer.

[0145] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope of protection.

Claims

1. A secondary frequency regulation method for a hybrid energy storage system, the hybrid energy storage system comprising a short-term high-power energy storage system and a lithium battery energy storage system, characterized in that, Including: Obtaining the grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium battery energy storage system; Determining the operating state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium battery energy storage system; Determining the secondary frequency modulation strategy to be operated according to the grid frequency deviation value, wherein the secondary frequency modulation strategy to be operated includes a secondary frequency modulation charging strategy and a secondary frequency modulation discharging strategy. If the grid frequency deviation value is positive, the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation charging strategy. If the grid frequency deviation value is negative, the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation discharging strategy; Calculating the charge and discharge power parameters based on a preset formula, and operating the secondary frequency modulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters.

2. The secondary frequency regulation method of the hybrid energy storage system according to claim 1, wherein If the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation charging strategy, calculating the charge and discharge power parameters based on a preset formula, and operating the secondary frequency modulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters includes: Calculating the charge and discharge power parameters based on a preset formula, wherein the charge and discharge power parameters include the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system; If the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system is higher than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system and the state of charge of the short-term high-power energy storage system are both in the operating state interval of the shallow charge and shallow discharge area, the short-term high-power energy storage system is preferentially used for charging, and the maximum charging power of the short-term high-power energy storage system is compared with the grid required power value. When the maximum charging power of the short-term high-power energy storage system is less than the grid required power value, the lithium battery energy storage system is used to supplement the remaining charging demand; If the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system is lower than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium battery energy storage system and the state of charge of the short-term high-power energy storage system are both in the deep charging area or the deep discharging area, the lithium battery energy storage system is preferentially used for charging, and the maximum charging power of the lithium battery energy storage system is compared with the grid required power value. When the maximum charging power of the lithium battery energy storage system is less than the grid required power value, the short-term high-power energy storage system is used to supplement the remaining charging demand.

3. The secondary frequency regulation method of the hybrid energy storage system according to claim 2, wherein The calculating the charge and discharge power parameters based on a preset formula includes: Calculating the maximum charging power of the short-term high-power energy storage system and the maximum charging power of the lithium battery energy storage system according to the following formula: Wherein, P cN,1 is the rated charging power of the short-time high-power energy storage system, n1 is a variable constant used to adjust the shape of the charging curve, P c,01 is used to limit the maximum power during the actual charging process of the short-time high-power energy storage system, SOC 1max is the maximum value of the charge setting of the short-time high-power energy storage system, SOC1 is the real-time state of charge of the short-time high-power energy storage system, SOC 1high is the high warning level of the charge setting of the short-time high-power energy storage system, P cN,2 is the rated charging power of the lithium battery energy storage system, P c,02 is used to limit the maximum power during the actual charging process of the lithium battery energy storage system, SOC 2max is the maximum value of the charge setting of the lithium battery energy storage system, SOC2 is the real-time state of charge of the lithium battery energy storage system, SOC 2high is the high warning level of the charge setting of the lithium battery energy storage system, P c1,max is the maximum charging power of the short-time high-power energy storage system, P c2,max is the maximum charging power of the lithium battery energy storage system.

4. The secondary frequency regulation method of the hybrid energy storage system according to claim 1, wherein If the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation discharging strategy, the calculating the charge and discharge power parameters based on a preset formula, and operating the secondary frequency modulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters includes: Calculate the charge and discharge power parameters based on a preset formula, where the charge and discharge power parameters include the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium-ion energy storage system; If the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system is lower than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system and the state of charge of the short-term high-power energy storage system are both in the operating state interval of the shallow charge and discharge region, then give priority to using the short-term high-power energy storage system for discharging. Compare the maximum discharge power of the short-term high-power energy storage system with the grid requirement power value. When the maximum discharge power of the short-term high-power energy storage system is less than the grid requirement power value, use the lithium-ion energy storage system to supplement the remaining discharge demand; If the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system is higher than the operating state interval of the short-term high-power energy storage system, or the operating state interval of the hybrid energy storage system is that the state of charge of the lithium-ion energy storage system and the state of charge of the short-term high-power energy storage system are both in the deep charge region or the deep discharge region, then give priority to using the lithium-ion energy storage system for discharging. Compare the maximum discharge power of the lithium-ion energy storage system with the grid requirement power value. When the maximum discharge power of the lithium-ion energy storage system is less than the grid requirement power value, use the short-term high-power energy storage system to supplement the remaining discharge demand.

5. The secondary frequency regulation method of the hybrid energy storage system according to claim 4, wherein The calculating the charge and discharge power parameters based on a preset formula includes: Calculate the maximum discharge power of the short-term high-power energy storage system and the maximum discharge power of the lithium-ion energy storage system according to the following formula: Wherein, P dN,1 is the rated discharge power of the short-term high-power energy storage system, n2 is a variable constant used to adjust the shape of the discharge curve, P d,01 is used to limit the maximum power during the actual discharge process of the short-term high-power energy storage system, SOC 1min is the minimum value of the charge setting of the short-term high-power energy storage system, SOC1 is the real-time state of charge of the short-term high-power energy storage system, SOC 1low is the low warning level of the charge setting of the short-term high-power energy storage system, P dN,2 is the rated discharge power of the lithium battery energy storage system, P d,02 is used to limit the maximum power during the actual discharge process of the lithium battery energy storage system, SOC 2min is the minimum value of the charge setting of the lithium battery energy storage system, SOC2 is the real-time state of charge of the lithium battery energy storage system, SOC 2low is the low warning level of the charge setting of the lithium battery energy storage system, P d1,max is the maximum discharge power of the short-term high-power energy storage system, P d2,max is the maximum discharge power of the lithium battery energy storage system.

6. A secondary frequency regulation device for a hybrid energy storage system, the hybrid energy storage system comprising a short-term high-power energy storage system and a lithium battery energy storage system, characterized in that, including: A grid and energy storage parameter acquisition module, configured to acquire the grid frequency deviation value, the real-time state of charge of the short-term high-power energy storage system, and the real-time state of charge of the lithium-ion energy storage system; An interval division module, configured to determine the operating state interval of the hybrid energy storage system according to the real-time state of charge of the short-term high-power energy storage system and the real-time state of charge of the lithium-ion energy storage system; An operating strategy determination module, configured to determine the secondary frequency modulation strategy to be operated according to the grid frequency deviation value, where the secondary frequency modulation strategy to be operated includes a secondary frequency modulation charging strategy and a secondary frequency modulation discharging strategy. If the grid frequency deviation value is positive, the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation charging strategy. If the grid frequency deviation value is negative, the secondary frequency modulation strategy to be operated is determined as the secondary frequency modulation discharging strategy; A strategy operation module, configured to calculate the charge and discharge power parameters based on a preset formula, and operate the secondary frequency modulation strategy to be operated according to the operating state interval of the hybrid energy storage system and the charge and discharge power parameters.

7. A computer device, characterized in that, including: A memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the secondary frequency modulation method of the hybrid energy storage system according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the secondary frequency modulation method of the hybrid energy storage system according to any one of claims 1 to 5.

9. A simulation system for the frequency regulation control strategy of a hybrid energy storage system, which is used to conduct simulation tests on the secondary frequency regulation method of the hybrid energy storage system described in any one of claims 1 to 5, characterized in that, Including: A power grid simulation device for simulating the operation scenario of the power grid section; A hybrid energy storage unit for charge and discharge management and protection of the hybrid energy storage system; A hybrid energy storage frequency modulation simulation system for simulating the master station instruction trigger and its allocation mechanism of secondary frequency modulation by constructing a power grid power-frequency characteristic model, generating power disturbances and power deviations according to experimental settings, and realizing the simulation and simulation process of secondary frequency modulation; A hybrid energy storage monitoring system for information collection, monitoring and protection of the hybrid energy storage unit; A hybrid energy storage energy management system for calculating the energy storage output instruction value in real time according to the secondary frequency modulation method of the hybrid energy storage system and sending it to the hybrid energy storage unit to realize the rapid optimization operation of the secondary frequency modulation energy storage power; A frequency modulation performance evaluation system for evaluating and calculating the performance of the hybrid energy storage system's frequency modulation response and evaluating the effectiveness of the secondary frequency modulation method of the hybrid energy storage system.

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