CN113690904A - Output smoothing system and method of photovoltaic energy storage system - Google Patents

Output smoothing system and method of photovoltaic energy storage system Download PDF

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Publication number
CN113690904A
CN113690904A CN202110978482.8A CN202110978482A CN113690904A CN 113690904 A CN113690904 A CN 113690904A CN 202110978482 A CN202110978482 A CN 202110978482A CN 113690904 A CN113690904 A CN 113690904A
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energy storage
storage system
power
photovoltaic
value
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施静辉
孙金龙
刘骏
裴淼
屠巍伟
陈鑫
王超博
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Guoneng Bayannur New Energy Co ltd
Envision Energy Co Ltd
Envision Energy Ltd
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Guoneng Bayannur New Energy Co ltd
Envision Energy Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/004—Generation forecast, e.g. methods or systems for forecasting future energy generation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E70/00—Other energy conversion or management systems reducing GHG emissions
    • Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin

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  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention provides a system and a method for smoothing output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system comprises a photovoltaic power generation system and an energy storage system, and the method comprises the following steps: the rough adjusting module determines a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system; and the fine adjustment module determines the fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to the difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the total output power of the smooth photovoltaic energy storage system of the energy storage system.

Description

Output smoothing system and method of photovoltaic energy storage system
Technical Field
The invention relates to the technical field of smart power grids and energy storage and conversion, in particular to a system and a method for smoothing output of a photovoltaic energy storage system.
Background
Due to the characteristics of uncertainty, instability and the like of photovoltaic power generation and the like, output power is not stable due to instantaneous rise or fall of power generated by photovoltaic power generation, and the grid-connected power of photovoltaic power generation fluctuates continuously. Moreover, as the proportion of photovoltaic power generation in the power grid is increased, the smooth control of the output power of solar power generation is receiving more and more attention.
With the continuous development of batteries and integration technologies thereof, smoothing solar power generation output by using battery energy storage power stations becomes a feasible scheme gradually. Through the converter of reasonable control connection on energy storage equipment, high-efficient charge-discharge that realizes energy storage system can solve the unstable problem of photovoltaic power generation output power that brings because photovoltaic power generation randomness, intermittent type nature and volatility etc. to a great extent to satisfy solar energy power generation's smooth output requirement, and effectively solve because photovoltaic power generation undulant electric energy quality scheduling problem that brings for the electric wire netting frequency fluctuation. The light-storage combined power generation system is essentially a multi-energy system, and how to coordinate the work of each power supply system is a key problem in the research and development of multi-energy hybrid power generation systems. In addition, in the smoothing process, quick and accurate compensation is not easy to achieve.
Disclosure of Invention
The invention aims to provide a system and a method for smoothing output of a photovoltaic energy storage system, which aim to solve the problem that the conventional photovoltaic energy storage system cannot compensate quickly and accurately in the smoothing process.
The invention also aims to provide a system and a method for smoothing output of the photovoltaic energy storage system, so as to solve the problem of how to coordinate the work of each power supply system of the photovoltaic energy storage system.
In order to solve the above technical problems, the present invention provides a method for smoothing output of a photovoltaic energy storage system,
the photovoltaic energy storage system comprises a photovoltaic power generation system and an energy storage system, and the method comprises the following steps:
the rough adjusting module determines a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system;
and the fine adjustment module determines the fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to the difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the total output power of the smooth photovoltaic energy storage system of the energy storage system.
Optionally, in the output smoothing method for the photovoltaic energy storage system, determining, by the rough adjustment module, a rough adjustment power value of the energy storage system according to a set rough adjustment value calculation method includes:
determining a coarse fluctuation control range set value according to the maximum fluctuation ratio allowed under each application scene; and
and determining a coarse adjustment power value of the energy storage system, wherein the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and a coarse adjustment fluctuation control range set value.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the fine tuning module according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system includes:
determining a difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; and
and processing the difference value through a first-order filtering algorithm to obtain a fine tuning power value.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes: the total output power of the photovoltaic energy storage system is obtained by the following formula:
Figure BDA0003228233980000021
wherein:
Pbess_realis the output power of the energy storage system;
Pne_prepredicting power of the photovoltaic power generation system;
Pne_realthe real-time power of the photovoltaic power generation system;
Pout_realthe total output power of the photovoltaic energy storage system;
ksetsetting a coarse adjustment fluctuation control range;
t is a time constant, the larger the value of T is, the smaller the differential power result is, and the better the smoothing effect is.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes:
the real-time acquisition system acquires the current state and the current charge state of the energy storage system, wherein the current state comprises a normal state, an abnormal state and a fault state; and
the real-time acquisition system acquires the real-time power of the photovoltaic power generation system.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes: processing according to the current state of the energy storage system acquired by the real-time acquisition system, and performing real-time circulation;
if the current state is a normal state, entering a smooth compensation allowing mode;
if the current state is an abnormal state, entering a pause and repair mode;
and if the current state is a fault state, entering a smooth compensation forbidding mode.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes: disabling the smoothing compensation mode includes:
the energy storage system does not output power, and a grid-connected point of the photovoltaic power generation system directly outputs real-time power of photovoltaic power generation;
the fault states comprise a battery system fault of the energy storage system, a PCS fault of the energy storage converter, a serious fault of the energy storage environment control system, a fire protection system fault and the like, and the faults can cause the energy storage system to be incapable of working or influence the safe and stable operation of the energy storage system.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes: the allowable smoothing compensation mode includes:
the photovoltaic power generation power prediction platform outputs the predicted power of the photovoltaic power generation power in the current time period;
the real-time power of photovoltaic power generation output by the system is collected in real time;
the rough adjusting module determines a rough adjusting power value of the energy storage system according to the predicted power so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system;
the fine-tuning module determines a fine-tuning power value of the energy storage system by using a fine-tuning value control algorithm according to a difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the energy storage system for smoothing the total output power of the photovoltaic energy storage system;
and coarsely adjusting the power value and finely adjusting the power value, calculating the output power of the energy storage system in real time, discharging the energy storage system if the calculated output power is a positive value, and charging the energy storage system if the calculated output power is a negative value.
Optionally, in the output smoothing method for the photovoltaic energy storage system, the method further includes: judging whether the energy storage system has a charging condition or a discharging condition according to the calculated output power and the current charge state acquired by the real-time acquisition system, wherein:
if the output power is positive and the current state of charge is less than the low threshold, no discharge condition exists;
if the output power is negative and the current state of charge is greater than the high threshold, no charging condition is available;
otherwise, the energy storage system has a charging condition and a discharging condition, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system form the total output power at the grid-connected point;
when the energy storage system does not have a charging condition or a discharging condition, the grid-connected point of the photovoltaic power generation system directly outputs the real-time power of photovoltaic power generation;
and under the condition that the current charge state is larger than the third threshold, the energy storage system discharges according to the value of the current charge state.
The invention also provides a system for smoothing output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system comprises a photovoltaic power generation system and an energy storage system, and the system comprises:
the rough adjusting module is configured to determine a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system;
and the fine adjustment module is configured to determine a fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to a difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the accuracy of the energy storage system in smoothing the total output power of the photovoltaic energy storage system.
The inventor of the invention finds that, through research, in the prior art, a method for determining the optimal configuration of the capacity of the energy storage system through a clear smoothing method exists, and focuses on the configuration of the optimal energy storage capacity; fitting an ideal smooth output curve by using historical photovoltaic power generation data, determining the output of stored energy by using the magnitude relation between the actual output of the photovoltaic power generation and the ideal smooth output, and determining the output calculation of the stored energy by focusing on the point; and the energy storage system output smoothing method aims at smoothing photovoltaic power generation, the charge state of the energy storage system is kept at a proper level, the continuous charge and discharge capacity of the energy storage system is improved, the smoothing capacity and the performance index of the energy storage system are cooperatively optimized, and the control of the energy storage system is emphasized. The above prior art does not pay attention to the control process of the whole photovoltaic system and the relation between the energy storage system and the ultra-short-term power generation prediction data of the photovoltaic system.
In the output smoothing system and method of the photovoltaic energy storage system provided by the invention, the supporting power (which can be positive or negative) required by the energy storage system for smoothing the real-time power of the photovoltaic power generation system is calculated as a rough power value; the method has the advantages that the predicted value of the power output of the photovoltaic power generation system and the power difference of the actual output of the photovoltaic power generation system are used, a control algorithm (a fine adjustment value control algorithm) is introduced for fine adjustment, the calculation result is used as a fine adjustment power value, the method of mutually combining coarse adjustment and fine adjustment is realized, and the photovoltaic energy storage smooth control with quicker response and more accurate control can be met.
According to the photovoltaic ultra-short-term power generation prediction method, on the basis of photovoltaic ultra-short-term power generation prediction data, under the premise that the current state and the current charge state of the energy storage system are taken as constraint conditions, the current state of the energy storage system acquired by the real-time acquisition system is processed, whether the energy storage system has a charging condition or a discharging condition is judged, and cooperative control among the whole system parts is achieved.
Drawings
Fig. 1 is a schematic diagram of a power output smoothing system structure and relationships among various parameters of a photovoltaic energy storage system according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for smoothing output of a photovoltaic energy storage system according to an embodiment of the present invention;
fig. 3 is a control block diagram illustrating the calculation of the total output power in the output smoothing method of the photovoltaic energy storage system according to an embodiment of the present invention.
Detailed Description
The invention is further elucidated with reference to the drawings in conjunction with the detailed description.
It should be noted that the components in the figures may be exaggerated and not necessarily to scale for illustrative purposes. In the figures, identical or functionally identical components are provided with the same reference symbols.
In the present invention, "disposed on …", "disposed over …" and "disposed over …" do not exclude the presence of an intermediate therebetween, unless otherwise specified. Further, "disposed on or above …" merely indicates the relative positional relationship between two components, and may also be converted to "disposed below or below …" and vice versa in certain cases, such as after reversing the product direction.
In the present invention, the embodiments are only intended to illustrate the aspects of the present invention, and should not be construed as limiting.
In the present invention, the terms "a" and "an" do not exclude the presence of a plurality of elements, unless otherwise specified.
It is further noted herein that in embodiments of the present invention, only a portion of the components or assemblies may be shown for clarity and simplicity, but those of ordinary skill in the art will appreciate that, given the teachings of the present invention, required components or assemblies may be added as needed in a particular scenario. Furthermore, features from different embodiments of the invention may be combined with each other, unless otherwise indicated. For example, a feature of the second embodiment may be substituted for a corresponding or functionally equivalent or similar feature of the first embodiment, and the resulting embodiments are likewise within the scope of the disclosure or recitation of the present application.
It is also noted herein that, within the scope of the present invention, the terms "same", "equal", and the like do not mean that the two values are absolutely equal, but allow some reasonable error, that is, the terms also encompass "substantially the same", "substantially equal". By analogy, in the present invention, the terms "perpendicular", "parallel" and the like in the directions of the tables also cover the meanings of "substantially perpendicular", "substantially parallel".
The numbering of the steps of the methods of the present invention does not limit the order of execution of the steps of the methods. Unless specifically stated, the method steps may be performed in a different order.
The output smoothing system and method of the photovoltaic energy storage system according to the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
The invention aims to provide a system and a method for smoothing output of a photovoltaic energy storage system, which aim to solve the problem that the conventional photovoltaic energy storage system cannot compensate quickly and accurately in the smoothing process.
The invention also aims to provide a system and a method for smoothing output of the photovoltaic energy storage system, so as to solve the problem of how to coordinate the work of each power supply system of the photovoltaic energy storage system.
In order to achieve the above object, the present invention provides a system and a method for smoothing output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system comprises a photovoltaic power generation system and an energy storage system, and the method comprises: the rough adjusting module determines a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system; and the fine adjustment module determines the fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to the difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the total output power of the smooth photovoltaic energy storage system of the energy storage system.
An embodiment of the present invention provides a method for smoothing output of a photovoltaic energy storage system, as shown in fig. 1, where the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system 30, and the method includes: the rough adjusting module 10 determines a rough adjusting power value of the energy storage system 30 according to a set rough adjusting value calculation method so as to improve the response speed of the energy storage system 30 for smoothing the total output power of the photovoltaic energy storage system; the fine-tuning module 20 determines a fine-tuning power value of the energy storage system 30 by using a fine-tuning value control algorithm according to a difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, so as to improve the accuracy of the energy storage system 30 in smoothing the total output power of the photovoltaic energy storage system.
In an embodiment of the present invention, as shown in fig. 1 and 3, in the output smoothing method for a photovoltaic energy storage system, the determining, by a coarse tuning module, a coarse tuning power value of the energy storage system according to a set coarse tuning value calculation method includes: the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and the set value of the coarse adjustment fluctuation control range; the value of the set value of the coarse fluctuation control range is based on the maximum fluctuation ratio allowed under each application scene (set by each local electric power company).
In an embodiment of the present invention, as shown in fig. 1 and 3, in the output smoothing method for a photovoltaic energy storage system, the determining, by a trimming module, a trimming power value of the energy storage system using a trimming value control algorithm according to a difference between a real-time power of the photovoltaic power generation system and a predicted power of the photovoltaic power generation system includes: determining a difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; and performing first-order filtering algorithm processing on the difference value to obtain a fine tuning power value.
In one embodiment of the invention, coarse adjustment is carried out to obtain a coarse adjustment value within a certain range according to smooth fluctuation control, a first-order filtering is adopted to calculate the fine adjustment value, and after passing battery SOC verification, photovoltaic power generation output is combined and output. As shown in fig. 3, in the output smoothing method of the photovoltaic energy storage system, the method further includes: the total output power of the photovoltaic energy storage system is obtained by the following formula:
Figure BDA0003228233980000071
wherein:
Pbess_realis the output power of the energy storage system;
Pne_prepredicting power of the photovoltaic power generation system;
Pne_realthe real-time power of the photovoltaic power generation system;
Pout_realthe total output power of the photovoltaic energy storage system;
ksetsetting a coarse adjustment fluctuation control range;
t is a time constant, the larger the value of T is, the smaller the differential power result is, and the better the smoothing effect is.
As shown in fig. 2, in the output smoothing method of the photovoltaic energy storage system, the method further includes: the real-time acquisition system acquires the current state and the current charge state of the energy storage system, wherein the current state comprises a normal state, an abnormal state and a fault state; and the real-time acquisition system acquires the real-time power of the photovoltaic power generation system.
In an embodiment of the present invention, in the method for smoothing output of a photovoltaic energy storage system, the method further includes: processing according to the current state of the energy storage system acquired by the real-time acquisition system (step of judging whether the energy storage system is normal as shown in fig. 2), and performing real-time circulation; if the current state is a normal state (yes), entering a smooth compensation allowing mode; if the current state is an abnormal state, entering a pause and repair mode; and if the current state is the fault state (No), entering a smooth compensation forbidding mode.
In an embodiment of the present invention, in the method for smoothing output of a photovoltaic energy storage system, the method further includes: disabling the smoothing compensation mode includes: the energy storage system does not output power, and the grid-connected point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation (jumping to the ending step shown in fig. 2); the fault states comprise a battery system fault of the energy storage system, a PCS fault of the energy storage converter, a serious fault of the energy storage environment control system, a fire protection system fault and the like, and the faults can cause the energy storage system to be incapable of working or influence the safe and stable operation of the energy storage system.
In an embodiment of the present invention, in the method for smoothing output of a photovoltaic energy storage system, the method further includes: the allowable smoothing compensation mode includes: as shown in fig. 2, the photovoltaic power generation power prediction platform outputs the predicted power of the photovoltaic power generation power in the current time period (step of obtaining ultra-short-term predicted data of optical power as shown in fig. 2); the real-time power of the photovoltaic power generation output by the real-time acquisition system (the step of acquiring the actual photovoltaic output by sampling as shown in fig. 2); as shown in fig. 1 and 3, the rough adjusting module determines a rough adjusting power value of the energy storage system according to the predicted power, so as to increase a response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system (in the step of calculating the rough adjusting value of the energy storage output shown in fig. 2); as shown in fig. 1 and 3, the fine-tuning module determines a fine-tuning power value of the energy storage system by using a fine-tuning value control algorithm according to a difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, so as to improve the precision of the energy storage system for smoothing the total output power of the photovoltaic energy storage system (step of calculating a fine-tuning value of energy storage output shown in fig. 2); as shown in fig. 1 to 3, the power value is coarsely adjusted and the power value is finely adjusted, the output power of the energy storage system is calculated in real time (in the step of calculating the output power of the energy storage system shown in fig. 2), if the calculated output power is a positive value, the energy storage system is discharged, and if the calculated output power is a negative value, the energy storage system is charged.
From a battery perspective, both overcharge and overdischarge can have an effect on the life of the battery. Therefore, it is necessary to monitor the State of Charge (SOC) of the battery and control the SOC of the battery within a certain range. Moreover, in a combined light-storage power generation system, if there is no reasonably effective control strategy to omit monitoring of the remaining state of charge of the energy storage battery, unnecessary battery capacity and use cost may be increased.
Based on the above insight, in an embodiment of the present invention, in the method for smoothing output of a photovoltaic energy storage system, the method further includes: according to the calculated output power and the current state of charge acquired by the real-time acquisition system, judging whether the energy storage system has a charging condition or a discharging condition (as shown in fig. 2, judging whether the energy storage SOC meets the step), wherein: if the output power is positive and the current state of charge is less than the low threshold, no discharge condition exists; if the output power is negative and the current state of charge is greater than the high threshold, no charging condition is available; otherwise, the energy storage system has a charging condition and a discharging condition, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system form the total output power at the grid-connected point (as shown in the step of calculating the light storage combined output value in fig. 2); when the energy storage system does not have the charging condition or the discharging condition, the grid-connected point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation (the ending step shown in fig. 2 is skipped); and under the condition that the current charge state is larger than the third threshold, the energy storage system discharges according to the value of the current charge state.
The present invention further provides a system for smoothing output of a photovoltaic energy storage system, as shown in fig. 1, the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system 30, and includes: a rough adjusting module 10 configured to determine a rough adjusting power value of the energy storage system 30 according to a set rough adjusting value calculation method to increase a response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system; and the fine-tuning module 20 is configured to determine a fine-tuning power value of the energy storage system 30 by using a fine-tuning value control algorithm according to a difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the energy storage system for smoothing the total output power of the photovoltaic energy storage system.
The method not only focuses on the control process of the whole photovoltaic system, but also controls according to the relation between the energy storage system and the ultra-short-term power generation prediction data of the photovoltaic system.
In the output smoothing system and method of the photovoltaic energy storage system provided by the invention, the supporting power (which can be positive or negative) required by the energy storage system for smoothing the real-time power of the photovoltaic power generation system is calculated as a rough power value; the method has the advantages that the predicted value of the power output of the photovoltaic power generation system and the power difference of the actual output of the photovoltaic power generation system are used, a control algorithm (a fine adjustment value control algorithm) is introduced for fine adjustment, the calculation result is used as a fine adjustment power value, the method of mutually combining coarse adjustment and fine adjustment is realized, and the photovoltaic energy storage smooth control with quicker response and more accurate control can be met.
According to the photovoltaic ultra-short-term power generation prediction method, based on the photovoltaic ultra-short-term power generation prediction data, under the precondition that the current state and the current charge state of the energy storage system are taken as constraint conditions, the current state of the energy storage system collected by the real-time collection system is processed, whether the energy storage system has a charging condition or a discharging condition is judged, and smooth collaborative output among the whole system parts is achieved.
The core of the method for smoothing photovoltaic energy storage output residing in ultra-short-term photovoltaic power prediction data comprises a method combining rough adjustment and fine adjustment, under the condition that a smoothing target is determined, an adjustment initial output value is rapidly determined according to the rough adjustment, and then correction is carried out through fine adjustment through a control algorithm (first-order filtering, PID and the like) according to the difference value between the real-time output of a photovoltaic power generation system and the ultra-short-term prediction data, so that the control precision is ensured.
Based on the ultra-short-period photovoltaic power generation power prediction data, the energy storage output coarse adjustment value can be calculated in advance, and the coarse adjustment speed is high, so that the overall response time is shortened; the difference value between the actual output power and the predicted value of the photovoltaic power generation is used as a fine adjustment value, and a control algorithm is introduced for fine adjustment, so that the adjustment precision is integrally improved; by using the method combining rough adjustment and fine adjustment, the energy storage system aiming at smoothing the photovoltaic power generation output has higher response speed and higher precision.
In summary, the above embodiments describe in detail different configurations of the output smoothing system and method of the photovoltaic energy storage system, and it is understood that the present invention includes but is not limited to the configurations listed in the above embodiments, and any modifications made on the configurations provided by the above embodiments are within the scope of the present invention. One skilled in the art can take the contents of the above embodiments to take a counter-measure.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims (10)

1. A method for smoothing output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system comprises a photovoltaic power generation system and an energy storage system, the method comprising:
the rough adjusting module determines a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system;
and the fine adjustment module determines the fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to the difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the total output power of the smooth photovoltaic energy storage system of the energy storage system.
2. The method of claim 1, wherein determining the coarse power value for the energy storage system from the coarse tuning module according to the set coarse tuning value calculation method comprises:
determining a coarse fluctuation control range set value according to the maximum fluctuation ratio allowed under each application scene; and
and determining a coarse adjustment power value of the energy storage system, wherein the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and a coarse adjustment fluctuation control range set value.
3. The method of claim 1, wherein the step of smoothing the output of the photovoltaic energy storage system by the trimming module based on the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system comprises:
determining a difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; and
and processing the difference value through a first-order filtering algorithm to obtain a fine tuning power value.
4. The method of smoothing output of a photovoltaic energy storage system of claim 1, further comprising: the total output power of the photovoltaic energy storage system is obtained by the following formula:
Figure FDA0003228233970000011
wherein:
Pbess_realis the output power of the energy storage system;
Pne_prepredicting power of the photovoltaic power generation system;
Pne_realthe real-time power of the photovoltaic power generation system;
Pout_realthe total output power of the photovoltaic energy storage system;
ksetsetting a coarse adjustment fluctuation control range;
t is a time constant, the larger the value of T is, the smaller the differential power result is, and the better the smoothing effect is.
5. The method of smoothing output of a photovoltaic energy storage system of claim 1, further comprising:
the real-time acquisition system acquires the current state and the current charge state of the energy storage system, wherein the current state comprises a normal state, an abnormal state and a fault state; and
the real-time acquisition system acquires the real-time power of the photovoltaic power generation system.
6. The method of smoothing output of a photovoltaic energy storage system of claim 5, further comprising: processing according to the current state of the energy storage system acquired by the real-time acquisition system, and performing real-time circulation;
if the current state is a normal state, entering a smooth compensation allowing mode;
if the current state is an abnormal state, entering a pause and repair mode;
and if the current state is a fault state, entering a smooth compensation forbidding mode.
7. The method of smoothing output of a photovoltaic energy storage system of claim 6, further comprising: disabling the smoothing compensation mode includes:
the energy storage system does not output power, and a grid-connected point of the photovoltaic power generation system directly outputs real-time power of photovoltaic power generation;
the fault states comprise a battery system fault of the energy storage system, a PCS fault of the energy storage converter, a serious fault of the energy storage environment control system and a fault of the fire protection system.
8. The method of smoothing output of a photovoltaic energy storage system of claim 6, further comprising: the allowable smoothing compensation mode includes:
the photovoltaic power generation power prediction platform outputs the predicted power of the photovoltaic power generation power in the current time period;
the real-time power of photovoltaic power generation output by the system is collected in real time;
the rough adjusting module determines a rough adjusting power value of the energy storage system according to the predicted power so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system;
the fine-tuning module determines a fine-tuning power value of the energy storage system by using a fine-tuning value control algorithm according to a difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the precision of the energy storage system for smoothing the total output power of the photovoltaic energy storage system;
and coarsely adjusting the power value and finely adjusting the power value, calculating the output power of the energy storage system in real time, discharging the energy storage system if the calculated output power is a positive value, and charging the energy storage system if the calculated output power is a negative value.
9. The method of smoothing a photovoltaic energy storage system output of claim 8, further comprising: judging whether the energy storage system has a charging condition or a discharging condition according to the calculated output power and the current charge state acquired by the real-time acquisition system, wherein:
if the output power is positive and the current state of charge is less than the low threshold, no discharge condition exists;
if the output power is negative and the current state of charge is greater than the high threshold, no charging condition is available;
otherwise, the energy storage system has a charging condition and a discharging condition, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system form the total output power at the grid-connected point;
when the energy storage system does not have the charging condition or the discharging condition, the grid-connected point of the photovoltaic power generation system directly outputs the real-time power of photovoltaic power generation.
10. A system for smoothing output of a photovoltaic energy storage system, the photovoltaic energy storage system comprising a photovoltaic power generation system and an energy storage system, comprising:
the rough adjusting module is configured to determine a rough adjusting power value of the energy storage system according to a set rough adjusting value calculation method so as to improve the response speed of the total output power of the energy storage system smoothing photovoltaic energy storage system; and
and the fine adjustment module is configured to determine a fine adjustment power value of the energy storage system by using a fine adjustment value control algorithm according to a difference value between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system so as to improve the accuracy of the energy storage system in smoothing the total output power of the photovoltaic energy storage system.
CN202110978482.8A 2021-08-25 2021-08-25 Output smoothing system and method of photovoltaic energy storage system Pending CN113690904A (en)

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