Multi-type energy storage device grading coordination control method and system
阅读说明：本技术 一种多类型储能装置分级协调控制方法及系统 (Multi-type energy storage device grading coordination control method and system ) 是由 柳伟 覃淇 蒋成涛 徐航 张义会 张思聪 于 2021-08-26 设计创作，主要内容包括：一种多类型储能装置分级协调控制方法及系统,属于配电网和储能技术领域,解决由太阳能或负载突然变化引起的交流电网功率波动的问题；储能装置协调控制器实时采集光伏发电装置发电侧功率以及交流电网负荷侧功率两者的功率差值即为总不平衡功率；根据总不平衡功率的大小调用一级储能装置和/或二级储能装置对总不平衡功率进行平抑,调用二级储能装置时,采用经验模态分解的方法将总的不平衡功率进行分解,得到不同频率下的分量,再结合二级储能装置的功率型储能装置和能量型储能装置的响应特性,对高频功率和低频功率分别进行平抑；实现了对功率波动的精准调节；同时对储能装置的充放电进行限制,确保储能装置的使用安全,延长其使用寿命。(A multi-type energy storage device grading coordination control method and a system belong to the technical field of power distribution networks and energy storage, and solve the problem of alternating current power grid power fluctuation caused by sudden change of solar energy or load; the energy storage device coordination controller collects the power difference value of the power generation side of the photovoltaic power generation device and the power of the load side of the alternating current power grid in real time, and the power difference value is the total unbalanced power; calling a primary energy storage device and/or a secondary energy storage device according to the total unbalanced power to stabilize the total unbalanced power, when calling the secondary energy storage device, decomposing the total unbalanced power by adopting an empirical mode decomposition method to obtain components under different frequencies, and then respectively stabilizing high-frequency power and low-frequency power by combining the response characteristics of the power type energy storage device and the energy type energy storage device of the secondary energy storage device; accurate adjustment of power fluctuation is realized; and meanwhile, the charging and discharging of the energy storage device are limited, so that the use safety of the energy storage device is ensured, and the service life of the energy storage device is prolonged.)
1. A hierarchical coordination control method for multi-type energy storage devices is applied to a hierarchical coordination control system, and the hierarchical coordination control system comprises the following steps: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the photovoltaic power generation device, the primary energy storage device and the secondary energy storage device are connected to an alternating current power grid through a converter, and a load is connected with the alternating current power grid; the photovoltaic power generation device adopts MPPT control to supply power to an alternating current power grid at the maximum power, and when the illumination intensity or the load changes, the energy storage device coordination controller is used for controlling the primary energy storage device and/or the secondary energy storage device to stabilize the total unbalanced power Ps；
The hierarchical coordination control method comprises the following steps:
s1, the energy storage device coordination controller collects power P of the power generation side of the photovoltaic power generation device in real timePVAnd AC grid load side power PLoadThe power difference between the two is the total unbalanced power Ps；
S2, the energy storage device coordination controller according to the total unbalanced power PsThe primary energy storage device and/or the secondary energy storage device are/is called to the total unbalanced power PsThe stabilization was carried out as follows:
the first mode is as follows: if the total unbalanced power PsIn the primary energy storage device coordination preset power range and the current primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller only calls the primary energy storage device to carry out the total unbalanced power PsCarrying out stabilization;
and a second mode: if the total unbalanced power PsExceeding the first-level energy storage device coordination preset power rangeAnd when the primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller calls the primary and secondary energy storage devices to jointly carry out the treatment on the total unbalanced power PsCarrying out stabilization;
and a third mode: if the current primary energy storage device is in a state of being incapable of charging and discharging, the energy storage device coordination controller only calls the secondary energy storage device to the total unbalanced power PsCarrying out stabilization;
and S3, when the secondary energy storage device is called, decomposing the total unbalanced power by adopting an empirical mode decomposition method to obtain components under different frequencies, and respectively stabilizing the high-frequency power and the low-frequency power by combining the response characteristics of the power type energy storage device and the energy type energy storage device of the secondary energy storage device.
2. The method according to claim 1, wherein the calling of only one energy storage device in mode one is used to control total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the primary energy storage device is the total unbalanced power Ps。
3. The method as claimed in claim 2, wherein the calling the primary and secondary energy storage devices in the second mode jointly controls the total unbalanced power PsStabilizing is carried out, wherein the reference unbalanced power set by the primary energy storage device is the rated power of the primary energy storage device, and the reference unbalanced power set by the secondary energy storage device is the total unbalanced power PsThe difference from the rated power of the primary energy storage device.
4. The method as claimed in claim 3, wherein the step of calling only the secondary energy storage device in the third mode is used to control the total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the secondary energy storage device is the total unbalanced power Ps。
5. The method as claimed in claim 4, wherein the primary energy storage device is a flywheel energy storage device, and the secondary energy storage device comprises a storage battery energy storage device and a super capacitor energy storage device.
6. A hierarchical coordination control system of multi-type energy storage device, characterized by comprising: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the photovoltaic power generation device, the primary energy storage device and the secondary energy storage device are connected to an alternating current power grid through a converter, and a load is connected with the alternating current power grid; the photovoltaic power generation device adopts MPPT control to supply power to an alternating current power grid at the maximum power, and when the illumination intensity or the load changes, the energy storage device coordination controller is used for controlling the primary energy storage device and/or the secondary energy storage device to stabilize the total unbalanced power Ps；
Energy storage device coordinated controller collects power P of power generation side of photovoltaic power generation device in real timePVAnd AC grid load side power PLoadThe power difference between the two is the total unbalanced power Ps；
The energy storage device coordination controller is used for controlling the energy storage device to work according to the total unbalanced power PsThe primary energy storage device and/or the secondary energy storage device are/is called to the total unbalanced power PsThe stabilization was carried out as follows:
the first mode is as follows: if the total unbalanced power PsIn the primary energy storage device coordination preset power range and the current primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller only calls the primary energy storage device to carry out the total unbalanced power PsCarrying out stabilization;
and a second mode: if the total unbalanced power PsIf the primary energy storage device exceeds the coordination preset power range and the primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller calls the primary and secondary energy storage devices to jointly carry out adjustment on the total unbalanced power PsCarrying out stabilization;
and a third mode: if the current primary energy storage device is in a state of being incapable of charging and discharging, thenThe energy storage device coordination controller only calls the secondary energy storage device to the total unbalanced power PsCarrying out stabilization;
when the secondary energy storage device is called, the total unbalanced power is decomposed by adopting an empirical mode decomposition method to obtain components under different frequencies, and then the high-frequency power and the low-frequency power are respectively stabilized by combining the response characteristics of the power type energy storage device and the energy type energy storage device of the secondary energy storage device.
7. The hierarchical coordination control system for multiple types of energy storage devices according to claim 6, characterized in that said one-level energy storage device is only called in mode one to adjust total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the primary energy storage device is the total unbalanced power Ps。
8. The hierarchical coordination control system for multiple types of energy storage devices according to claim 7, wherein said invoking of the primary and secondary energy storage devices in mode two is for the total unbalanced power P togethersStabilizing is carried out, wherein the reference unbalanced power set by the primary energy storage device is the rated power of the primary energy storage device, and the reference unbalanced power set by the secondary energy storage device is the total unbalanced power PsThe difference from the rated power of the primary energy storage device.
9. The hierarchical coordination control system for multiple types of energy storage devices according to claim 8, characterized in that said mode three only calls for secondary energy storage device to balance total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the secondary energy storage device is the total unbalanced power Ps。
10. The hierarchical coordination control system for multiple types of energy storage devices according to claim 9, characterized in that said primary energy storage device is a flywheel energy storage device, and said secondary energy storage device comprises a battery energy storage device and a super capacitor energy storage device.
Technical Field
The invention belongs to the technical field of power distribution networks and energy storage, and relates to a hierarchical coordination control method and system for multiple types of energy storage devices.
Background
The distributed photovoltaic power generation system can improve the utilization efficiency of traditional non-renewable energy sources, can well comprehensively utilize various renewable resources, is an important policy and measure for realizing green environmental protection, low carbon and emission reduction, and supplements centralized power generation. When the solar distributed microgrid operates independently, distributed energy storage becomes a key part for maintaining the stability of the microgrid, can effectively inhibit power fluctuation caused by sudden change of solar energy and load, keeps the stability of the microgrid system, and plays an important role in maintaining the stable quality of electric energy of the system and ensuring the dynamic balance of power. In the prior art, a document "wind power hybrid energy storage system energy management coordination control strategy based on ensemble empirical mode decomposition" (feijxia, institute of electrical engineering of Xinjiang university, proceedings of electrical and technology) published in 5 months in 2019 adopts a storage battery-super capacitor hybrid energy storage system to stabilize wind power fluctuation and realize smooth grid connection of wind power. The document does not provide for a hierarchical control of the energy storage means.
The energy storage device is a cyclic process that energy is stored in a certain mode by utilizing a specific medium and released in a certain mode on occasions needing the energy. In recent years, the energy storage technology is developed rapidly and has a good development prospect. The application of the energy storage technology can bring far-reaching influence on the aspects of traditional power grid operation, scheduling, planning and the like. At the present stage, many energy storage devices have been developed and utilized, and among them, storage battery energy storage, super capacitor energy storage, flywheel energy storage and the like have been widely researched and applied. Energy storage media can be classified into energy type and power type. Energy-type energy storage media are represented by lithium batteries, lead-acid batteries, all-vanadium redox flow batteries, and the like, and have high energy density, high storage capacity, low power density, and long response time. The power type energy storage medium is represented by a super capacitor, flywheel energy storage and superconducting magnetic energy storage, has high power density, low storage capacity and short response time, can be charged and discharged frequently without damaging the performance, and has low energy density.
Storage battery energy storage is one of the most promising and widely applied energy storage modes at present, and includes a plurality of types, such as lead-acid batteries, lithium ion batteries, flow batteries, sodium-sulfur batteries, and the like, and although the technical maturity is different, large-capacity storage has been realized. The lead-acid battery has the widest application and the most mature technology, the conversion efficiency is generally 85% -90%, and the lead-acid battery is suitable for long-time storage due to low self-discharge rate, but has short service life; the lithium ion battery is a new novel secondary battery, has high energy storage density, small volume, no pollution, long cycle life and high energy storage density, but has high production cost; the flow battery is a novel energy storage technology, can realize large-scale storage, has long cycle service life, but has low energy density and larger occupied space.
The super capacitor is a porous medium made of special materials, is developed according to the theory of electrochemical double-electrode layers, has higher dielectric constant and larger storage capacity which can reach 20-1000 times of the common capacitor compared with the common capacitor, and has very high cycle life and power density. The power density of the battery can reach 100W/kg-1000W/kg, which is far higher than that of a storage battery. The super capacitor has the advantages of fast response speed and high charging and discharging efficiency, but has low energy density, and can only maintain high-power charging and discharging for a short time, so the super capacitor is commonly used for short-time energy storage.
Flywheel energy storage belongs to a mechanical energy storage mode, generally comprises a high-speed flywheel, a generator/motor, a bearing system, a control system and the like, wherein a motor rotor and the flywheel store electric energy in the form of mechanical energy,the motor drives the flywheel to accelerate, and the electric energy is converted into mechanical energy; when the energy is released, the flywheel drives the generator to rotate, and the kinetic energy is converted into electric energy. The energy density of the flywheel can reach 100Wh/kg, and the power density is generally more than 5 multiplied by 103W/kg, the energy conversion efficiency is more than 90%, and the method has the advantages of high use efficiency, short construction period, high energy storage, long service life and the like, and is high in response speed, free of pollution and simple in operation and maintenance.
Disclosure of Invention
The invention aims to design and relate to a multi-type energy storage device grading coordination control method and system, which are used for grading control of energy storage devices in a distributed photovoltaic power generation system so as to solve the problem of alternating current power grid power fluctuation caused by sudden change of solar energy or load.
The invention solves the technical problems through the following technical scheme:
a hierarchical coordination control method for multi-type energy storage devices is applied to a hierarchical coordination control system, and the hierarchical coordination control system comprises the following steps: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the photovoltaic power generation device, the primary energy storage device and the secondary energy storage device are connected to an alternating current power grid through a converter, and a load is connected with the alternating current power grid; the photovoltaic power generation device adopts MPPT control to supply power to an alternating current power grid at the maximum power, and when the illumination intensity or the load changes, the energy storage device coordination controller is used for controlling the primary energy storage device and/or the secondary energy storage device to stabilize the total unbalanced power Ps；
The hierarchical coordination control method comprises the following steps:
s1, the energy storage device coordination controller collects power P of the power generation side of the photovoltaic power generation device in real timePVAnd AC grid load side power PLoadThe power difference between the two is the total unbalanced power Ps；
S2, the energy storage device coordination controller according to the total unbalanced power PsThe primary energy storage device and/or the secondary energy storage device are/is called to the total unbalanced power PsThe stabilization was carried out as follows:
the first mode is as follows: if the total unbalanced power PsIn the primary energy storage device coordination preset power range and the current primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller only calls the primary energy storage device to carry out the total unbalanced power PsCarrying out stabilization;
and a second mode: if the total unbalanced power PsIf the primary energy storage device exceeds the coordination preset power range and the primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller calls the primary and secondary energy storage devices to jointly carry out adjustment on the total unbalanced power PsCarrying out stabilization;
and a third mode: if the current primary energy storage device is in a state of being incapable of charging and discharging, the energy storage device coordination controller only calls the secondary energy storage device to the total unbalanced power PsCarrying out stabilization;
and S3, when the secondary energy storage device is called, decomposing the total unbalanced power by adopting an empirical mode decomposition method to obtain components under different frequencies, and respectively stabilizing the high-frequency power and the low-frequency power by combining the response characteristics of the power type energy storage device and the energy type energy storage device of the secondary energy storage device.
According to the technical scheme, the energy storage device coordination controller optimizes the distribution of compensation power to coordinate the mutual cooperation of the primary energy storage device and the secondary energy storage device in different operation modes, so that the accurate regulation of power fluctuation is realized; and meanwhile, the charging and discharging of the energy storage device are limited, so that the use safety of the energy storage device is ensured, the service life of the energy storage device is prolonged, and the whole system can operate safely and stably.
A hierarchical coordination control method for multi-type energy storage devices is applied to a hierarchical coordination control system, and the hierarchical coordination control system comprises the following steps: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the photovoltaic power generation device, the primary energy storage device and the secondary energy storage device are connected to an alternating current power grid through a converter, and a load is connected with the alternating current power grid;
as a further improvement of the technical scheme of the invention, the mode I only calls the primary energy storage device pairUnbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the primary energy storage device is the total unbalanced power Ps。
As a further improvement of the technical scheme of the invention, the primary energy storage device and the secondary energy storage device are called in the mode II to jointly carry out the total unbalanced power PsStabilizing is carried out, wherein the reference unbalanced power set by the primary energy storage device is the rated power of the primary energy storage device, and the reference unbalanced power set by the secondary energy storage device is the total unbalanced power PsThe difference from the rated power of the primary energy storage device.
As a further improvement of the technical scheme of the invention, the mode three only calls the secondary energy storage device to the total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the secondary energy storage device is the total unbalanced power Ps。
As a further improvement of the technical scheme of the invention, the primary energy storage device adopts a flywheel energy storage device, and the secondary energy storage device comprises a storage battery energy storage device and a super capacitor energy storage device.
A hierarchical coordination control system of multi-type energy storage devices, comprising: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the photovoltaic power generation device, the primary energy storage device and the secondary energy storage device are connected to an alternating current power grid through a converter, and a load is connected with the alternating current power grid; the photovoltaic power generation device adopts MPPT control to supply power to an alternating current power grid at the maximum power, and when the illumination intensity or the load changes, the energy storage device coordination controller is used for controlling the primary energy storage device and/or the secondary energy storage device to stabilize the total unbalanced power Ps；
Energy storage device coordinated controller collects power P of power generation side of photovoltaic power generation device in real timePVAnd AC grid load side power PLoadThe power difference between the two is the total unbalanced power Ps；
The energy storage device coordination controller is used for controlling the energy storage device to work according to the total unbalanced power PsThe primary energy storage device and/or the secondary energy storage device are/is called to the total unbalanced power PsCarry out stabilization, haveThe body conditions are as follows:
the first mode is as follows: if the total unbalanced power PsIn the primary energy storage device coordination preset power range and the current primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller only calls the primary energy storage device to carry out the total unbalanced power PsCarrying out stabilization;
and a second mode: if the total unbalanced power PsIf the primary energy storage device exceeds the coordination preset power range and the primary energy storage device is in a state of being capable of charging and discharging, the energy storage device coordination controller calls the primary and secondary energy storage devices to jointly carry out adjustment on the total unbalanced power PsCarrying out stabilization;
and a third mode: if the current primary energy storage device is in a state of being incapable of charging and discharging, the energy storage device coordination controller only calls the secondary energy storage device to the total unbalanced power PsCarrying out stabilization;
when the secondary energy storage device is called, the total unbalanced power is decomposed by adopting an empirical mode decomposition method to obtain components under different frequencies, and then the high-frequency power and the low-frequency power are respectively stabilized by combining the response characteristics of the power type energy storage device and the energy type energy storage device of the secondary energy storage device.
As a further improvement of the technical scheme of the invention, in the mode I, only the primary energy storage device is called to control the total unbalanced power PsCarrying out stabilization, wherein the reference unbalanced power set by the primary energy storage device is the total unbalanced power Ps。
As a further improvement of the technical scheme of the invention, the primary energy storage device and the secondary energy storage device are called in the mode II to jointly carry out the total unbalanced power PsStabilizing is carried out, wherein the reference unbalanced power set by the primary energy storage device is the rated power of the primary energy storage device, and the reference unbalanced power set by the secondary energy storage device is the total unbalanced power PsThe difference from the rated power of the primary energy storage device.
As a further improvement of the technical scheme of the invention, the mode three only calls the secondary energy storage device to the total unbalanced power PsPerforming stabilization, wherein reference is set for the secondary energy storage deviceThe unbalanced power being the total unbalanced power Ps。
As a further improvement of the technical scheme of the invention, the primary energy storage device adopts a flywheel energy storage device, and the secondary energy storage device comprises a storage battery energy storage device and a super capacitor energy storage device.
The invention has the advantages that:
(1) according to the technical scheme, the energy storage device coordination controller optimizes the distribution of compensation power to coordinate the mutual cooperation of the primary energy storage device and the secondary energy storage device in different operation modes, so that the accurate regulation of power fluctuation is realized; and meanwhile, the charging and discharging of the energy storage device are limited, so that the use safety of the energy storage device is ensured, the service life of the energy storage device is prolonged, and the whole system can operate safely and stably.
(2) According to the technical scheme, the hybrid energy storage system formed by combining the super capacitor and the storage battery according to respective advantages of the super capacitor and the storage battery can realize performance complementation, and greatly improves the performance of the energy storage system.
Drawings
FIG. 1 is a topological diagram of a multi-type energy storage system hierarchical coordination control system;
FIG. 2 is a flow chart of a multi-type energy storage system hierarchical coordination control method;
FIG. 3 is a power curve for a primary energy storage device and a secondary energy storage device;
FIG. 4 is a graph of the natural mode function of the reference power after empirical mode decomposition;
FIG. 5 is a power distribution curve for a super capacitor energy storage device and a battery energy storage device.
Detailed Description
In order to make the objects, 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 embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The technical scheme of the invention is further described by combining the drawings and the specific embodiments in the specification:
example one
As shown in fig. 1, the hierarchical coordination control system of the present embodiment includes: the system comprises a photovoltaic power generation device, a primary energy storage device, a secondary energy storage device, an energy storage device coordination controller and a load; the primary energy storage device adopts a flywheel energy storage device, the secondary energy storage device adopts a storage battery energy storage device and a super capacitor energy storage device respectively, the photovoltaic power generation device and the flywheel energy storage device, the storage battery energy storage device and the super capacitor energy storage device are connected into an alternating current power grid through a converter, and a load is connected with the alternating current power grid; the photovoltaic power generation device adopts MPPT control to supply power to an alternating current power grid at the maximum power, and when the illumination intensity or the load changes, the energy storage device coordination controller is used for controlling the primary energy storage device and/or the secondary energy storage device to stabilize the unbalanced power Ps。
As shown in fig. 2, which is a flowchart of the hierarchical coordination control method, the hybrid energy storage coordination control system is implemented by the following steps:
(1) energy storage device coordinated controller collects power P of power generation side of photovoltaic power generation device in real timePVAnd AC grid load side power PLoadThe power difference between the two is the unbalanced power Ps；
(2) The first mode is as follows: when the energy storage device coordination controller judges PsWithin a preset range PrAnd when the power is in the middle, only the flywheel energy storage device is called to stabilize the unbalanced power. PrThe reference power of the flywheel energy storage device is the unbalanced power P under the mode of only calling the flywheel energy storage device selected according to the rated power of the flywheel energy storage devicesConverting the reference power into a rotating speed and transmitting the rotating speed to the flywheel energy storage device for control, wherein the power and the rotating speed of the flywheel energy storage device have the following relation:
in the formula, ωnRepresenting a given following angular velocity of the flywheel, J represents the moment of inertia of the flywheel.
The working angular speed interval of the flywheel in the embodiment of the invention is 150 rad/s-2200 rad/s, and the interval is divided into 3 parts, namely a low speed area (< 314rad/s), a normal working area (314 rad/s-2000 rad/s) and a high speed area (>2000 rad/s). When the flywheel rotational speed is located normal work area, carry out charge-discharge according to rated power, when the rotational speed reaches low-speed district upper limit or high-speed district lower limit, the flywheel keeps current rotational speed, no longer continues charge-discharge, lets the rotational speed remain in normal work area all the time, and concrete regulation strategy is as follows:
in the formula: pfRepresents a reference power;represents the adjusted power; omegafRepresenting the current flywheel speed; omegabRepresenting a low-speed region critical value; omegatIndicating a high velocity region threshold.
(3) And a second mode: when the power P is unbalanced, as shown in FIG. 3sExceeding the individually stabilized power range of the flywheel energy storage device, satisfying the charging and discharging conditions of the flywheel energy storage device, namely the rotating speed is in the normal working interval, coordinating and stabilizing the flywheel energy storage device, the storage battery energy storage device and the super capacitor energy storage device together, charging and discharging the flywheel energy storage device according to the rated power, and then using P to control the charging and discharging of the flywheel energy storage devicesSubtracting the rated power of the flywheel to obtain the reference unbalanced power P of a secondary coordination device, namely a storage battery energy storage device and a super capacitor energy storage devicee。
(4) And a third mode: if the current flywheel energy storage device is in a state of being incapable of charging and discharging, the energy storage device coordination controller only calls the electric power storagePair of unbalanced power P of pool energy storage device and super capacitor energy storage devicesTo carry out stabilization and unbalance power PsNamely the reference unbalanced power P of the storage battery energy storage device and the super capacitor energy storage devicee。
(5) Referring to the unbalanced power P by empirical mode decomposition, as shown in FIG. 4eDecomposed into a series of natural mode functions (IMFs) with frequencies distributed from high to low. As shown in FIG. 5, P is obtained by summing the high frequency component and the low frequency component, respectivelyscAnd PbatA 1 is to PscAnd PbatThe reference power of the super capacitor energy storage device and the reference power of the storage battery energy storage device are respectively used for controlling charging and discharging of the super capacitor energy storage device and the storage battery energy storage device, and the specific regulation strategy is as follows:
in the formula: p represents the power before the overcharge and overdischarge adjustment; p*Indicating the adjusted power after overcharge and overdischarge; SOCxIndicating the current state of charge of the energy storage system; SOCminRepresents a discharge lower limit value; SOCmaxRepresents the charging region upper limit value.
According to the technical scheme of the embodiment, if the unbalanced power is within the preset range, the energy storage system is controlled to enter a flywheel independent operation mode to stabilize the power; if the power distribution exceeds the preset range, the flywheel is used as a primary coordination device, the storage battery and the super capacitor are used as secondary coordination devices, and the control system performs power distribution on the three energy storage devices to coordinate control. The flywheel has higher power density than a storage battery and higher energy density than a super capacitor, and is an energy storage device between the storage battery and the super capacitor, and the charging and discharging cycle life of the flywheel reaches hundreds of thousands of times, so that the purpose of adjusting the system power can be achieved only by using the flywheel to adjust the system power within a certain interval range of power fluctuation, the charging and discharging times of the storage battery and the super capacitor can be reduced, and the service life of the whole energy storage system can be prolonged.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
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