CN103904666A - Load peak period energy allocating method for grid-connected photovoltaic energy storage system - Google Patents

Abstract

The invention relates to a load peak period energy allocating method for a grid-connected photovoltaic energy storage system. According to the method, according to the peak fluctuation characteristic of power grid needs in a load peak period, the weighted allocating method is designed, so that the fluctuation characteristic of electric energy which can be provided by the grid-connected photovoltaic energy storage system is kept consistent with that of electric energy needed by a power grid, then the condition that electric energy stored in an electric power generation system in the load peak period is spent too early is avoided, and continuity and stability of supply and demand of the power grid in the period are ensured.

Description

A kind of load peak phase energy concocting method of grid-connected photovoltaic energy-storage system

Technical field

The present invention relates to photovoltaic energy storage technical field, particularly relate to a kind of energy concocting method of grid-connected photovoltaic energy storage.

Background technology

Extensive development new forms of energy are Strategic Demands of national economy and social sustainable development.Solar energy is generally acknowledge widely distributed, uses safe high-quality new forms of energy, and photovoltaic generation is as the mode of efficiently utilizing solar energy resources, and its research and application are day by day paid attention to and promote, and become the useful of traditional energy and supplement.But being different from the maximum of tradition generating, photovoltaic generation is characterised in that it is affected by the external environment such as intensity of illumination and temperature and the stochastic volatility that produces, therefore, large capacity energy-accumulating power station (energy-storage system) is as an emerging technology, be used in conjunction with grid-connected photovoltaic power generation system, form extensive grid-connected photovoltaic energy-storage system, can greatly optimize the grid-connected characteristic of photovoltaic generation, and how distribute the energy resource supply of extensive grid-connected photovoltaic energy-storage system rationally, become important research topic.

The optimization problem of grid-connected photovoltaic energy-storage system relates to all many-sides, contains the multi-field technology such as power electronics, electrochemistry, control, communication.The present invention is intended to supply with not abundant situation for load peak phase electric energy, discloses a kind of simple but efficient, practical electric energy concocting method.

From currently available technology, the concocting method that limited electric energy of load peak phase is supplied with roughly divides two classes: a class is advanced intelligent algorithm, such as linear programming, genetic algorithm, neural net etc., its shortcoming is that algorithm is partially complicated, thus lower feasibility and the practicality of affecting of efficiency; Another kind of is traditional deployment algorithm, and its essential idea is that current available electrical energy is distributed equally or is similar to mean allocation by the peak value period, and its shortcoming is not consider the curve characteristic of peak period electrical network loading demand, thereby affects the performance optimization of system.

Therefore, need the technical problem that those skilled in the art solve to be exactly: how to consider to match with the curve characteristic of electrical network loading demand, design a kind of electric energy blending technology of highly effective, thereby realize the optimization supply of limited electric energy of load peak phase.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of energy concocting method of grid-connected photovoltaic energy-storage system, supplies with in order to the optimization that realizes limited electric energy of load peak phase.

In order to address the above problem, the invention discloses a kind of load peak phase energy concocting method of grid-connected photovoltaic energy-storage system, described method comprises:

A, according to season of living in determine " load peak phase " [t _{peak_start}, t _{peak_end}], wherein t _{peak_start}and t _{peak_end}the initial sum that is respectively the load peak phase stops the moment;

B, the current residing time t of the system of obtaining;

C, judge that whether t is in " load peak phase " [t _{peak_start}, t _{peak_end}] in:

D, if so, enter " peak value processing module ", that is: current stored electric energy is allocated, obtain the electric energy E that current time t should distribute _share(t) be:

$E_{\mathrm{share}}\left(t\right)=E_{\mathrm{stor}\_\mathrm{avaliable}}\left(\frac{w_{t\_\mathrm{curve}}+w_{t\_\mathrm{ave}}}{2}\right)$

Be E _share(t) by current available storage of electrical energy E _{stor_avaliable}with weight coefficient (w _{t_curve}+ w _{t_ave})/2 product obtains.Wherein, E _{stor_avaliable}=E _stor(t-1)-E _{stor_min}be the storage of electrical energy E of a moment t-1 _stor(t-1) with system minimum memory electric energy E _{stor_min}difference; Weight coefficient (w _{t_curve}+ w _{t_ave})/2 are by " curve weighting w _{t_curve}" and " average weighted w _{t_ave}" two parts composition, be respectively calculated as follows:

$w_{t\_\mathrm{<figure-callout\; id="1"\; label="curve"\; filenames="HDA0000469427130000021.png"\; state="\{\{state\}\}">curve</figure-callout>}}\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{stark}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right)$

$w_{t\_\mathrm{ave}}=\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}$

Thereby the electric energy E that current time t should distribute _share(t) finally can be calculated as:

$E_{\mathrm{share}}\left(t\right)=\frac{1}{2}\{(\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{start}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right))+\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}\}\{E_{\mathrm{stor}}(t-1)-E_{\mathrm{stor}\_\min }\};$

E, if not, enters " non-peak value processing module ", according to loading demand, according to traditional distribution according to need principle, current stored electric energy is offered to current time load required that is:.

Compared with prior art, the present invention has the following advantages:

The load peak phase energy concocting method of a kind of grid-connected photovoltaic energy-storage system provided by the invention, supply with not abundant situation for load peak phase electric energy, " weighted calculation of the class load curve " method of employing is allocated current stored electric energy, thereby the wave characteristic that electric energy that grid-connected photovoltaic energy-storage system can provide and the required electric energy of electrical network are consistent, the situation of having avoided the electric energy of conventional method load peak phase electricity generation system storage to use up too early.In addition, compared with complicated intelligent algorithm, its efficient, practical allotment flow process then clearly implementation step be easier to the Project Realization of system.

Accompanying drawing explanation

Fig. 1 is the flow chart of the load peak phase energy concocting method of a kind of grid-connected photovoltaic energy-storage system described in the embodiment of the present invention;

Fig. 2 is the system global structure schematic diagram of the load peak phase energy concocting method of a kind of grid-connected photovoltaic energy-storage system described in the embodiment of the present invention;

Fig. 3 is the realization flow schematic diagram of the load peak phase energy concocting method of a kind of grid-connected photovoltaic energy-storage system described in the embodiment of the present invention.

Embodiment

For above-mentioned purpose of the present invention, feature and advantage can be become apparent more, below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.

With reference to Fig. 1, show a kind of flow chart of load peak phase energy concocting method of grid-connected photovoltaic energy-storage system, described method specifically comprises:

Step S101, according to season of living in determine " load peak phase " [t _{peak_start}, t _{peak_end}];

Step S102, the current residing time t of the system of obtaining;

Whether step S103, judgement t be in " load peak phase " [t _{peak_start}, t _{peak_end}] in:

Step S104, if so, enter " peak value processing module ", that is: current stored electric energy is allocated, obtain the electric energy E that current time t should distribute _share(t) be:

$E_{\mathrm{share}}\left(t\right)=E_{\mathrm{stor}\_\mathrm{avaliable}}\left(\frac{w_{t\_\mathrm{curve}}+w_{t\_\mathrm{ave}}}{2}\right)$

Be E _share(t) by current available storage of electrical energy E _{stor_avaliable}with weight coefficient (w _{t_curve}+ w _{t_ave})/2 product obtains.Wherein, E _{stor_avaliable}=E _stor(t-1)-E _{stor_min}be the storage of electrical energy E of a moment (being t-1) _stor(t-1) with system minimum memory electric energy E _{stor_min}difference; Weight coefficient (w _{t_curve}+ w _{t_ave})/2 are by " curve weighting w _{t_curve}" and " average weighted w _{t_ave}" two parts composition, be respectively calculated as follows:

$w_{t\_\mathrm{<figure-callout\; id="1"\; label="curve"\; filenames="HDA0000469427130000021.png"\; state="\{\{state\}\}">curve</figure-callout>}}\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{stark}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right)$

$w_{t\_\mathrm{ave}}=\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}$

Thereby the electric energy E that current time t should distribute _share(t) finally can be calculated as:

$E_{\mathrm{share}}\left(t\right)=\frac{1}{2}\{(\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{start}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right))+\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}\}\{E_{\mathrm{stor}}(t-1)-E_{\mathrm{stor}\_\min }\};$

Step S105, if not, enters " non-peak value processing module ", according to loading demand, according to traditional distribution according to need principle, current stored electric energy is offered to current time required that is:.

With reference to Fig. 2, show system global structure schematic diagram of the present invention, main thought is:

The electric energy of laod network is supplied with source totally three parts: " conventional power generation systems " (coal-fired etc. non-new forms of energy), " photovoltaic generating system " and " energy-storage system ".Wherein the electric energy of a photovoltaic generating system output part directly transfers to load, and another part transfers to energy-storage system.

Above-mentioned three part electric energy supplies will be delivered to " peak value judge module " and judge that whether t is in " load peak phase " [t _{peak_start}, t _{peak_end}] in, after judgement, carry out " peak value processing module " current stored electric energy is allocated, obtain the electric energy E that current time t should distribute _share(t), or " non-peak value processing module " is according to loading demand, according to traditional distribution according to need principle, current stored electric energy is offered to current time required, afterwards again through processing, obtains final electric energy output and delivers to laod network.

With reference to Fig. 3, show the method realization flow schematic diagram of the embodiment of the present invention, concrete steps are:

Step Step1, determines current season.For different regions, the difference that draws the line in season, will be divided into four seasons for 1 year conventionally, and each season, duration about three months, determined according to local meteorological data and empirical value.

Step Step2, determines the load peak phase [t in this season _{peak_start}, t _{peak_end}].After determining season, the peak period of its power load (load) can roughly be determined.The load peak phase in summer in for example somewhere, the Northern Hemisphere is [14:00,20:00], and the load peak phase in winter is [17:00,23:00].

Step Step3, the current residing time t of acquisition system.

Step Step4, judges that whether t is in " load peak phase " [t _{peak_start}, t _{peak_end}] in:

If so, illustrate current in the load peak phase, execution step Step5, Step6 and Step7;

If not, illustrate current not in the load peak phase, execution step Step8.

Step Step5-1, obtained the storage of electrical energy E in a upper moment _stor(t-1) with system minimum memory electric energy E _{stor_min};

Step Step5-2, calculates current available storage of electrical energy: E _{stor_avaliable}=E _stor(t- ¹)-E _{stor_min}.

Step Step6-1, calculates " curve weighting ": $w_{t\_\mathrm{<figure-callout\; id="1"\; label="curve"\; filenames="HDA0000469427130000021.png"\; state="\{\{state\}\}">curve</figure-callout>}}\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{stark}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right);$

Step Step6-2, calculates " average weighted ":

Step Step7, calculates the electric energy (load peak phase) that current time t should distribute:

$E_{\mathrm{share}}\left(t\right)=\frac{1}{2}\{(\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{start}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right))+\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}\}\{E_{\mathrm{stor}}(t-1)-E_{\mathrm{stor}\_\min }\};$

Step Step8, calculates the electric energy (unsupported peak period) that current time t should distribute:

E _share(t)=E _{stor_avaliable}。

Above the load peak phase energy concocting method of a kind of grid-connected photovoltaic energy-storage system provided by the present invention is described in detail, applied specific case herein principle of the present invention and execution mode are set forth, the explanation of above embodiment is just for helping to understand method of the present invention and core concept thereof; , for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention meanwhile.

Claims (1)

1. a flow chart for the load peak phase energy concocting method of grid-connected photovoltaic energy-storage system, is characterized in that, the method specifically comprises the steps:

Step S101, according to season of living in determine " load peak phase " [t _{peak_start}, t _{peak_end}];

Step S102, the current residing time t of the system of obtaining;

Whether step S103, judgement t be in " load peak phase " [t _{peak_start}, t _{peak_end}] in:

Step S104, if so, enter " peak value processing module ", that is: current stored electric energy is allocated, obtain the electric energy E that current time t should distribute _share(t) be:

$E_{\mathrm{share}}\left(t\right)=E_{\mathrm{stor}\_\mathrm{avaliable}}\left(\frac{w_{t\_\mathrm{curve}}+w_{t\_\mathrm{ave}}}{2}\right)$

Be E _share(t) by current available storage of electrical energy E _{stor_avaliable}with weight coefficient (w _{t_curve}+ w _{t_ave})/2 product obtains.Wherein, E _{stor_avaliable}=E _stor(t-1)-E _{stor_min}be the storage of electrical energy E of a moment (being t-1) _stor(t-1) with system minimum memory electric energy E _{stor_min}difference; Weight coefficient (w _{t_curve}+ w _{t_ave})/2 are by " curve weighting w _{t_curve}" and " average weighted w _{t_ave}" two parts composition, be respectively calculated as follows:

$w_{t\_\mathrm{curve}}\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{stark}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right)$

$w_{t\_\mathrm{ave}}=\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}$

Thereby the electric energy E that current time t should distribute _share(t) be finally calculated as:

$E_{\mathrm{share}}\left(t\right)=\frac{1}{2}\{(\frac{1}{2}-\frac{1}{2}\cos \left(\frac{t-t_{\mathrm{peak}\_\mathrm{start}}}{t_{\mathrm{peak}\_\mathrm{end}}-t_{\mathrm{peak}\_\mathrm{start}}}\mathrm{\&pi;}\right))+\frac{1}{t_{\mathrm{peak}\_\mathrm{end}}-t+1}\}\{E_{\mathrm{stor}}(t-1)-E_{\mathrm{stor}\_\min }\};$

Step S105, if not, enters " non-peak value processing module ", according to loading demand, according to traditional distribution according to need principle, current stored electric energy is offered to current time required that is:.

Images