CN118074195B  Distributed energy storage converter integrated system and power distribution method thereof  Google Patents
Distributed energy storage converter integrated system and power distribution method thereof Download PDFInfo
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 CN118074195B CN118074195B CN202410459406.XA CN202410459406A CN118074195B CN 118074195 B CN118074195 B CN 118074195B CN 202410459406 A CN202410459406 A CN 202410459406A CN 118074195 B CN118074195 B CN 118074195B
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Classifications

 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
 H02J3/36—Arrangements for transfer of electric power between ac networks via a hightension dc link

 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
 H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
 H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
 H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal

 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]
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Abstract
The invention discloses a distributed energy storage converter integrated system and a power distribution method thereof, belonging to the technical field of integrated energy storage converters, wherein the distributed energy storage converter integrated system comprises a plurality of energy storage converter modules which are mutually connected in parallel, an alternating current circuit breaking module and a metering device; each energy storage conversion module is respectively connected with the alternating current circuit breaking module and the metering device; each energy storage current transformation module comprises a battery cluster, a direct current breaker and an energy storage current transformer which are sequentially connected; the positive electrode and the negative electrode of the battery cluster are correspondingly connected with the positive electrode and the negative electrode of the direct current side of the energy storage converter through a direct current breaker; the alternating current side of the energy storage converter is connected in parallel by adopting a threephase fourwire system and is respectively connected with the alternating current circuit breaking module and the input side of the metering device; the output side of the metering device and the neutral line are externally connected with a power distribution system, so that grid connection is realized; the energy storage converter is used for carrying out bidirectional conversion on direct current and alternating current. The system solves the problem of insufficient equalization effect of mixed use of new and old battery clusters by combining a power distribution method.
Description
Technical Field
The invention belongs to the technical field of integrated energy storage converters, and particularly relates to a distributed energy storage converter integrated system and a power distribution method thereof.
Background
The existing energy storage converter generally adopts a centralized integration mode, and power devices therein are assembled in a centralized way, so that only one path of interface is arranged on the direct current side. When the existing energy storage converter is used, the battery clusters are connected in parallel and converged, and then connected into a direct current interface of the centralized energy storage converter.
The existing energy storage converter is mainly balanced and controlled by the BMS due to the fact that the existing energy storage converter is required to be connected in parallel at the direct current side, and the existing energy storage converter has a certain balancing effect on a new battery system no matter in active balancing or passive balancing, but the BMS is difficult to achieve an ideal balancing effect after the batteries are aged, and particularly the balancing of deviation among battery clusters is very difficult. When the system capacity reaches a certain degree, the problems of direct current arc discharge, parallel capacity loss at the direct current side, parallel circulation among battery clusters and the like can occur, the safety and the efficiency of the energy storage power station are affected, and the whole system is down if the whole system fails due to the fact that the power devices of the existing energy storage current transformer are piled up in a concentrated mode. The distributed energy storage is low in general capacity and dispersed in regions, and once the energy storage converter fails, the problems of long aftersale period and difficult maintenance are met.
Disclosure of Invention
In order to overcome the defects in the prior art, the distributed energy storage converter integrated system and the power distribution method thereof provided by the invention have the advantages that by configuring an independent energy storage converter module for each battery cluster and connecting the alternating current sides of the energy storage converters in parallel, the consistency requirements among the battery clusters are greatly reduced, even the mixed use of new and old battery clusters can be realized based on the power distribution method, and the problem of insufficient mixed use balance effect of the new and old battery clusters is solved.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
on one hand, the distributed energy storage converter integrated system provided by the invention comprises a plurality of energy storage converter modules which are mutually connected in parallel, an alternating current circuit breaking module and a metering device;
each energy storage conversion module is respectively connected with the alternating current circuit breaking module and the metering device;
Each energy storage current transformation module comprises a battery cluster, a direct current breaker and an energy storage current transformer which are sequentially connected; the positive electrode and the negative electrode of the battery cluster are correspondingly connected with the positive electrode and the negative electrode of the direct current side of the energy storage converter through a direct current breaker; the alternating current side of the energy storage converter is connected in parallel by adopting a threephase fourwire system and is respectively connected with the alternating current circuit breaking module and the input side of the metering device; the output side of the metering device and the neutral line are externally connected with a power distribution system, so that grid connection is realized; the energy storage converter is used for carrying out bidirectional conversion on direct current and alternating current.
The beneficial effects of the invention are as follows: according to the distributed energy storage converter integrated system, when one or a part of energy storage converter modules fail, the rest energy storage converter modules can still continue to operate, the system is maintained to be stable, the size of a single energy storage converter module is small, the weight is light, factory returning maintenance is facilitated, and the reliability and maintainability of the distributed energy storage converter integrated system are ensured; by matching a single energy storage converter for each battery cluster and connecting the alternating current sides of all the energy storage converters in parallel, the direct current sides of the energy storage converters are not required to be connected in parallel, the consistency requirement among the battery clusters is greatly reduced, the flexibility of power configuration of the energy storage converters is greatly enhanced, and even the mixed use of a new battery cabinet and an old battery cabinet can be realized; according to the invention, the current of the direct current side of the energy storage converter is reduced, the arc discharge and the capacity loss of the direct current side are effectively improved, and the safety performance and the efficiency of the system are improved.
Further, the power of each energy storage current transformation module is not identical.
The beneficial effects of adopting the further scheme are as follows: the distributed energy storage converter integrated system provided by the invention does not require the power to be completely consistent for each energy storage converter module connected in parallel, and can be combined with a power distribution method to realize the mixed use of new and old battery clusters.
On the other hand, the invention also provides a power distribution method based on the distributed energy storage converter integrated system, which comprises the following steps:
S1, acquiring active power and reactive power output to gridconnected points by an alternating current side of each energy storage converter, and constructing a sagging control model;
S2, constructing a phase angle difference model of the parallel energy storage converters based on active power and sagging control models output to gridconnected points at alternating current sides of the energy storage converters;
S3, neglecting system loss, and obtaining a phase angle power correlation model of the parallel energy storage converter based on a phase angle difference model of the parallel energy storage converter;
S4, obtaining a fuzzy active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter according to highresistance lowinductance characteristics of the power distribution network line;
S5, obtaining an output power distribution model and a target power model of the parallel energy storage converter based on the fuzzy active power ratio model of the parallel energy storage converter;
and S6, performing power distribution of the energy storage converters with different rated powers based on an output power distribution model and a target power model of the parallel energy storage converters so as to mix and connect the energy storage converters with different powers in parallel.
The beneficial effects of the invention are as follows: according to the power distribution method based on the distributed energy storage converter integrated system, the balanced coordination and parallel mixed use of the battery clusters with different powers can be realized through the analysis of the power and the phase angle based on the distributed energy storage converter integrated system, so that the balanced performance between the old battery and the new battery which are used for a period of time is effectively improved, and the stable operation of the distributed energy storage converter integrated system is effectively ensured.
Further, the step S1 includes the following steps:
S11, acquiring active power and reactive power from an alternating current output side of each energy storage converter to a gridconnected point;
The calculation expressions of the active power and the reactive power from the alternating current output side of the energy storage converter to the gridconnected point are as follows:
，
，
Wherein P represents the active power output to the gridconnected point by the alternating current side of the energy storage converter, U represents the voltage amplitude of the alternating current side of the energy storage converter, U _{W} represents the voltage of the gridconnected point, delta represents the phase angle of the alternating current side of the energy storage converter, delta _{W} represents the phase angle of the gridconnected point, and X _{W} represents the reactance of a line between the energy storage converter and the gridconnected point;
S12, enabling the difference value between the phase angle of the gridconnected point and the phase angle of the alternating current side of the energy storage converters to be smaller than a preset phase angle difference threshold value, and obtaining an active power phase angle correlation model and a reactive power amplitude correlation model based on active power and reactive power output to the gridconnected point by the alternating current side of each energy storage converter;
the calculation expressions of the active power phasor correlation model and the reactive power voltage amplitude correlation model are respectively as follows:
，
；
s13, constructing a sagging control model based on the active power phase angle correlation model and the reactive power amplitude correlation model;
the computational expression of the droop control model is as follows:
，
Wherein m represents a phase angle control parameter, δ _{e} represents a rated phase angle, P _{e} represents a rated active power, n represents an amplitude control parameter, U _{e} represents a rated voltage amplitude, and Q _{e} represents a rated reactive power.
The beneficial effects of adopting the further scheme are as follows: according to the invention, according to the reactance relation from the energy storage converter to the gridconnected point in each energy storage converter module, the active power and reactive power from the alternatingcurrent output side of each energy storage converter to the gridconnected point are obtained, and the active power phase angle correlation model, the reactive power amplitude correlation model and the sagging control model are constructed based on the condition that the phase angle difference between the phase angle of the grid point and the alternatingcurrent side of the energy storage converter is smaller by setting the phase angle difference threshold value, so that a foundation is provided for analyzing the relation between the phase angle and the power of each energy storage converter module in a sagging control mode and realizing the parallel mixed use of new and old battery clusters.
Further, the step S2 includes the following steps:
s21, constructing a gridconnected point phase angle difference model based on active power output to the gridconnected point by the output side of each energy storage converter;
The calculation expression of the gridconnected point phase angle difference model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{i} represents a phase angle of the ac side of the ith parallel energy storage converter, δ _{j} represents a phase angle of the ac side of the jth parallel energy storage converter, P _{i} represents an active power output from the ac side of the ith parallel energy storage converter to the gridconnected point, P _{j} represents an active power output from the ac side of the jth parallel energy storage converter to the gridconnected point, ω represents an angular frequency, L _{i} represents an output inductance corresponding to the ac side of the ith parallel energy storage converter, U _{i} represents a voltage amplitude of the ac side of the ith energy storage converter, L _{Di} represents a line inductance corresponding to the jth parallel energy storage converter, L _{j} represents a voltage amplitude of the ac side of the jth parallel energy storage converter, L _{Dj} represents a line inductance in the jth energy storage converter module, wherein i, j=1, 2, …, N, and i+noteq, N are the total number of energy storage converter modules;
S22, constructing a sagging model of the parallel energy storage converter based on the sagging control model;
The calculation expression of the sagging model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{ei} represents a rated droop phase angle corresponding to the ith parallel energy storage converter, m _{i} represents a phase angle control parameter corresponding to the ith parallel energy storage converter, P _{ei} represents a rated active power corresponding to the ith parallel energy storage converter, δ _{ej} represents a rated droop phase angle corresponding to the jth parallel energy storage converter, m _{j} represents a phase angle control parameter corresponding to the jth parallel energy storage converter, and P _{ej} represents a rated active power corresponding to the jth parallel energy storage converter;
s23, constructing a phase angle difference model of the parallel energy storage converter based on a gridconnected point phase angle difference model and a sagging model of the parallel energy storage converter;
the calculation expression of the phase angle difference model of the parallel energy storage converter is as follows:
，
。
The beneficial effects of adopting the further scheme are as follows: the invention provides a specific method for constructing a phase angle difference model of parallel energy storage converters based on active power and sagging control models output to gridconnected points at alternating sides of the energy storage converters, and provides a basis for analyzing the phase angle power relation of the parallel energy storage converters on the basis of the phase angle difference model of the parallel energy storage converters under the condition of neglecting system loss.
Further, the calculation expression of the phase angle power correlation model of the parallel energy storage converter is as follows:
，
Wherein P _{L} represents the total power of the parallel energy storage converters.
The beneficial effects of adopting the further scheme are as follows: the invention provides a calculation method of a phase angle power model of a parallel energy storage converter, which provides a basis for phase angle power analysis among parallel energy storage converter modules.
Further, the step S4 includes the following steps:
s41, obtaining an active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter;
the calculation expression of the active power ratio model of the parallel energy storage converter is as follows:
；
s42, based on an active power ratio model of the parallel energy storage converter, combining highresistance lowinductance characteristics of a power distribution network line to obtain a fuzzy active power ratio model of the parallel energy storage converter;
The calculation expression of the fuzzy active power ratio model of the parallel energy storage converter is as follows:
。
The beneficial effects of adopting the further scheme are as follows: the invention provides a method for obtaining a fuzzy active power ratio model of a parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter according to high resistance and low inductance characteristics of a power distribution network line.
Further, the calculation expression of the output power distribution model of the parallel energy storage converter is as follows:
Wherein P _{1} represents the active power output from the ac side of the 1 st parallel energy storage converter to the gridconnected point, m _{1} represents the phase angle control parameter corresponding to the 1 st parallel energy storage converter, P _{2} represents the active power output from the ac side of the 2 nd parallel energy storage converter to the gridconnected point, m _{2} represents the phase angle control parameter corresponding to the 2 nd parallel energy storage converter, P _{k} represents the active power output from the ac side of the k parallel energy storage converter to the gridconnected point, m _{k} represents the phase angle control parameter corresponding to the k parallel energy storage converter, P _{N} represents the active power output from the ac side of the N parallel energy storage converter to the gridconnected point, m _{N} represents the phase angle control parameter corresponding to the N parallel energy storage converter, P _{e1} represents the rated active power corresponding to the 1 st parallel energy storage converter, P _{e2} represents the rated active power corresponding to the 2 nd parallel energy storage converter, P _{ek} represents the active power corresponding to the k parallel energy storage converter, P _{eN} represents the rated active power corresponding to the N energy storage converter, wherein n=1, n=98.
The beneficial effects of adopting the further scheme are as follows: compared with the prior art that parallel operation is required to be performed by the same rated power, the calculation method of the output power distribution model of the parallel energy storage converter provided by the invention can be used for distributing the output power among energy storage conversion modules with different rated powers, namely, equalization among battery clusters is realized.
Further, the calculation expression of the target power model of the parallel energy storage converter is as follows:
Wherein P _{target} represents the converter integration target power.
The beneficial effects of adopting the further scheme are as follows: the invention provides a calculation method of a target power model of a parallel energy storage converter, wherein the target power of the parallel energy storage converter is the sum of the power of all the parallel energy storage converters, and the equalization effect of a battery cluster can be improved by combining an output power distribution model of the parallel energy storage converter.
Other advantages that are also present with respect to the present invention will be more detailed in the following examples.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a distributed energy storage converter integrated system according to embodiment 1 of the present invention.
Fig. 2 is a flow chart of steps of a power distribution method based on a distributed energy storage converter integrated system in embodiment 2 of the present invention.
Fig. 3 is a schematic diagram of a line power reactance between a single energy storage converter module and a gridconnected point in embodiment 2 of the present invention.
Fig. 4 is a schematic diagram of a line power reactance between a parallel energy storage converter module and a gridconnected point in embodiment 2 of the present invention.
Wherein, CT, current transformer; a PA ammeter; QF1, a first alternating current breaker; QF2, a second ac circuit breaker; SPD, surge protector; PEN, neutral.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present invention.
BMS (Battery MANAGEMENT SYSTEM), battery management system.
Example 1:
As shown in fig. 1, in one aspect, in an embodiment of the present invention, the present invention provides a distributed energy storage converter integrated system, including a plurality of energy storage converter modules connected in parallel with each other, and an ac disconnection module and a metering device;
each energy storage conversion module is respectively connected with the alternating current circuit breaking module and the metering device;
Each energy storage current transformation module comprises a battery cluster, a direct current breaker and an energy storage current transformer which are sequentially connected; the positive electrode and the negative electrode of the battery cluster are correspondingly connected with the positive electrode and the negative electrode of the direct current side of the energy storage converter through a direct current breaker; the alternating current side of the energy storage converter is connected in parallel by adopting a threephase fourwire system and is respectively connected with the alternating current circuit breaking module and the input side of the metering device; the output side of the metering device and the neutral line are externally connected with a power distribution system, so that grid connection is realized; the energy storage converter is used for carrying out bidirectional conversion on direct current and alternating current.
According to the invention, the alternating current sides of the energy storage converters are connected in parallel by adopting a threephase fourwire system, so that an isolation transformer is omitted, the cost of the system is effectively reduced, and the potential safety hazard of the fault of the isolation transformer to the system is eliminated.
In this embodiment, the ac short circuit module includes a second ac breaker QF2 and a surge protector SPD, one end of the second ac breaker QF2 is connected to the gridconnected point of each energy storage converter, the other end of the second ac breaker QF2 is connected to the surge protector SPD, in this embodiment, the stationary end of the second ac breaker QF2 is connected to the gridconnected point of each energy storage converter, the moving end of the second ac breaker QF2 is connected to the surge protector, and the surge protector is grounded; the metering device comprises a current transformer CT, an ammeter PA, a first alternating current breaker QF1 and a neutral line PEN; the current transformers CT are arranged on Aphase lines, Bphase lines and Cphase lines between grid connection points of alternating current side output ends of the energy storage converters and the power distribution system, the ammeter PA is arranged on neutral lines PEN between grid connection points of alternating current side output ends of the energy storage converters and the power distribution system, and the first alternating current circuit breaker QF1 is arranged between the current transformers CT on the Aphase lines, the Bphase lines and the Cphase lines and the power distribution system.
In this embodiment, the power of each energy storage converter module is not exactly the same. The distributed energy storage converter integrated system provided by the invention is also suitable for the situations that the power of each energy storage converter module is completely different, and the power of each energy storage converter module is partially the same or completely the same.
Example 2:
As shown in fig. 2, in another aspect, the present invention further provides a power distribution method based on a distributed energy storage converter integrated system, including the following steps:
S1, acquiring active power and reactive power output to gridconnected points by an alternating current side of each energy storage converter, and constructing a sagging control model;
The step S1 comprises the following steps:
S11, acquiring active power and reactive power from an alternating current output side of each energy storage converter to a gridconnected point;
As shown in fig. 3, reactance exists in a line between a single energy storage converter module and a gridconnected point, and active power and reactive power from the alternating current output end of each energy storage converter to the gridconnected point can be obtained from parameters such as voltage peak value and phase angle at the gridconnected point.
The calculation expressions of the active power and the reactive power from the alternating current output side of the energy storage converter to the gridconnected point are as follows:
，
，
Wherein P represents the active power output to the gridconnected point by the alternating current side of the energy storage converter, U represents the voltage amplitude of the alternating current side of the energy storage converter, U _{W} represents the voltage of the gridconnected point, delta represents the phase angle of the alternating current side of the energy storage converter, delta _{W} represents the phase angle of the gridconnected point, and X _{W} represents the reactance of a line between the energy storage converter and the gridconnected point;
S12, enabling the difference value between the phase angle of the gridconnected point and the phase angle of the alternating current side of the energy storage converters to be smaller than a preset phase angle difference threshold value, and obtaining an active power phase angle correlation model and a reactive power amplitude correlation model based on active power and reactive power output to the gridconnected point by the alternating current side of each energy storage converter;
the calculation expressions of the active power phasor correlation model and the reactive power voltage amplitude correlation model are respectively as follows:
，
；
s13, constructing a sagging control model based on the active power phase angle correlation model and the reactive power amplitude correlation model;
the computational expression of the droop control model is as follows:
，
Wherein m represents a phase angle control parameter, δ _{e} represents a rated phase angle, P _{e} represents a rated active power, n represents an amplitude control parameter, U _{e} represents a rated voltage amplitude, and Q _{e} represents a rated reactive power.
S2, constructing a phase angle difference model of the parallel energy storage converters based on active power and sagging control models output to gridconnected points at alternating current sides of the energy storage converters;
The step S2 comprises the following steps:
s21, constructing a gridconnected point phase angle difference model based on active power output to the gridconnected point by the output side of each energy storage converter;
The calculation expression of the gridconnected point phase angle difference model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{i} represents a phase angle of the ac side of the ith parallel energy storage converter, δ _{j} represents a phase angle of the ac side of the jth parallel energy storage converter, P _{i} represents an active power output from the ac side of the ith parallel energy storage converter to the gridconnected point, P _{j} represents an active power output from the ac side of the jth parallel energy storage converter to the gridconnected point, ω represents an angular frequency, L _{i} represents an output inductance corresponding to the ac side of the ith parallel energy storage converter, U _{i} represents a voltage amplitude of the ac side of the ith energy storage converter, L _{Di} represents a line inductance corresponding to the jth parallel energy storage converter, L _{j} represents a voltage amplitude of the ac side of the jth parallel energy storage converter, L _{Dj} represents a line inductance in the jth energy storage converter module, wherein i, j=1, 2, …, N, and i+noteq, N are the total number of energy storage converter modules;
S22, constructing a sagging model of the parallel energy storage converter based on the sagging control model;
The calculation expression of the sagging model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{ei} represents a rated droop phase angle corresponding to the ith parallel energy storage converter, m _{i} represents a phase angle control parameter corresponding to the ith parallel energy storage converter, P _{ei} represents a rated active power corresponding to the ith parallel energy storage converter, δ _{ej} represents a rated droop phase angle corresponding to the jth parallel energy storage converter, m _{j} represents a phase angle control parameter corresponding to the jth parallel energy storage converter, and P _{ej} represents a rated active power corresponding to the jth parallel energy storage converter;
In the embodiment, when the active power output and the phase angle of the parallel energy storage converter are both 0, the rated output power of the parallel energy storage converter can be obtained;
the calculation expression of the rated output power of the parallel energy storage converter is as follows:
，；
s23, constructing a phase angle difference model of the parallel energy storage converter based on a gridconnected point phase angle difference model and a sagging model of the parallel energy storage converter;
the calculation expression of the phase angle difference model of the parallel energy storage converter is as follows:
，
。
S3, neglecting system loss, and obtaining a phase angle power correlation model of the parallel energy storage converter based on a phase angle difference model of the parallel energy storage converter;
the calculation expression of the phase angle power correlation model of the parallel energy storage converter is as follows:
，
Wherein P _{L} represents the total power of the parallel energy storage converters.
As shown in fig. 4, in this embodiment, the case where there are only two parallel energy storage converters is exemplified, the voltage amplitude of the ac side of the 1 st energy storage converter is U _{1}, the phase angle of the ac side of the 1 st parallel energy storage converter is δ _{1}, and the output inductance corresponding to the 1 st parallel energy storage converter is L _{1}, The active power output to the gridconnected point by the alternatingcurrent side of the 1 st parallel energy storage converter is P _{1}, the reactive power output to the gridconnected point by the alternatingcurrent side of the 1 st parallel energy storage converter is Q _{1}, the voltage amplitude of the alternating current side of the 2 nd energy storage converter is U _{2}, the phase angle of the alternating current side of the 2 nd parallel energy storage converter is delta _{2}, the output inductance corresponding to the 2 nd parallel energy storage converter is L _{2}, the line inductance L _{D2} in the 2 nd energy storage converter module and the line resistance R _{D2} in the 2 nd energy storage converter module, The active power output from the alternatingcurrent side of the 2 nd parallel energy storage converters to the gridconnected point is P _{2}, the reactive power output from the alternatingcurrent side of the 2 nd parallel energy storage converters to the gridconnected point is Q _{2}, the total power of the corresponding parallel energy storage converters at the load of the final parallel point is P _{L}, The reactive power of the parallel energy storage converters corresponding to the load of the parallel point is Q _{L}, if P _{L}=P_{1}+P_{2} exists, the calculation expression of the phase angle power correlation model when two parallel energy storage converters exist is as follows:
，
Wherein, P _{1} represents the active power output from the ac side of the 1 st parallel energy storage converter to the gridconnected point, P _{2} represents the active power output from the ac side of the 2 nd parallel energy storage converter to the gridconnected point, L _{1} represents the output inductance corresponding to the 1 st parallel energy storage converter, U _{1} represents the voltage amplitude of the ac side of the 1 st parallel energy storage converter, L _{D1} represents the line inductance in the 1 st energy storage converter module, L _{2} represents the output inductance corresponding to the 2 nd parallel energy storage converter, U _{2} represents the voltage amplitude of the ac side of the 2 nd energy storage converter, L _{D2} represents the line inductance in the 2 nd energy storage converter module, m _{1} represents the phase angle control parameter corresponding to the 1 st parallel energy storage converter, m _{2} represents the phase angle control parameter corresponding to the 2 nd parallel energy storage converter; the active power output to the gridconnected point from the alternating current side of the 1 st energy storage converter and the 2 nd energy storage converter which are connected in parallel can be obtained respectively on the basis of the second time, and the active power is as follows:
，
；
S4, obtaining a fuzzy active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter according to highresistance lowinductance characteristics of the power distribution network line;
the step S4 comprises the following steps:
s41, obtaining an active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter;
the calculation expression of the active power ratio model of the parallel energy storage converter is as follows:
；
s42, based on an active power ratio model of the parallel energy storage converter, combining highresistance lowinductance characteristics of a power distribution network line to obtain a fuzzy active power ratio model of the parallel energy storage converter;
The calculation expression of the fuzzy active power ratio model of the parallel energy storage converter is as follows:
。
S5, obtaining an output power distribution model and a target power model of the parallel energy storage converter based on the fuzzy active power ratio model of the parallel energy storage converter;
The calculation expression of the output power distribution model of the parallel energy storage converter is as follows:
Wherein P _{1} represents the active power output from the ac side of the 1 st parallel energy storage converter to the gridconnected point, m _{1} represents the phase angle control parameter corresponding to the 1 st parallel energy storage converter, P _{2} represents the active power output from the ac side of the 2 nd parallel energy storage converter to the gridconnected point, m _{2} represents the phase angle control parameter corresponding to the 2 nd parallel energy storage converter, P _{k} represents the active power output from the ac side of the k parallel energy storage converter to the gridconnected point, m _{k} represents the phase angle control parameter corresponding to the k parallel energy storage converter, P _{N} represents the active power output from the ac side of the N parallel energy storage converter to the gridconnected point, m _{N} represents the phase angle control parameter corresponding to the N parallel energy storage converter, P _{e1} represents the rated active power corresponding to the 1 st parallel energy storage converter, P _{e2} represents the rated active power corresponding to the 2 nd parallel energy storage converter, P _{ek} represents the active power corresponding to the k parallel energy storage converter, P _{eN} represents the rated active power corresponding to the N energy storage converter, wherein n=1, n=98.
The calculation expression of the target power model of the parallel energy storage converter is as follows:
Wherein P _{target} represents the converter integration target power.
And S6, performing power distribution of the energy storage converters with different rated powers based on an output power distribution model and a target power model of the parallel energy storage converters so as to mix and connect the energy storage converters with different powers in parallel.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention.
Claims (7)
1. The power distribution method based on the distributed energy storage converter integrated system is characterized in that the distributed energy storage converter integrated system comprises a plurality of energy storage conversion modules which are mutually connected in parallel, an alternating current circuit breaking module and a metering device;
each energy storage conversion module is respectively connected with the alternating current circuit breaking module and the metering device;
each energy storage current transformation module comprises a battery cluster, a direct current breaker and an energy storage current transformer which are sequentially connected; the positive electrode and the negative electrode of the battery cluster are correspondingly connected with the positive electrode and the negative electrode of the direct current side of the energy storage converter through a direct current breaker; the alternating current side of the energy storage converter is connected in parallel by adopting a threephase fourwire system and is respectively connected with the alternating current circuit breaking module and the input side of the metering device; the output side of the metering device and the neutral line are externally connected with a power distribution system, so that grid connection is realized; the energy storage converter is used for carrying out bidirectional conversion on direct current and alternating current; the power of each energy storage current conversion module is not completely the same;
the power distribution method comprises the following steps:
S1, acquiring active power and reactive power output to gridconnected points by an alternating current side of each energy storage converter, and constructing a sagging control model;
S2, constructing a phase angle difference model of the parallel energy storage converters based on active power and sagging control models output to gridconnected points at alternating current sides of the energy storage converters;
S3, neglecting system loss, and obtaining a phase angle power correlation model of the parallel energy storage converter based on a phase angle difference model of the parallel energy storage converter;
S4, obtaining a fuzzy active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter according to highresistance lowinductance characteristics of the power distribution network line;
S5, obtaining an output power distribution model and a target power model of the parallel energy storage converter based on the fuzzy active power ratio model of the parallel energy storage converter;
and S6, performing power distribution of the energy storage converters with different rated powers based on an output power distribution model and a target power model of the parallel energy storage converters so as to mix and connect the energy storage converters with different powers in parallel.
2. The power distribution method based on the distributed energy storage converter integrated system according to claim 1, wherein S1 comprises the steps of:
S11, acquiring active power and reactive power from an alternating current output side of each energy storage converter to a gridconnected point;
The calculation expressions of the active power and the reactive power from the alternating current output side of the energy storage converter to the gridconnected point are as follows:
，
，
Wherein P represents the active power output to the gridconnected point by the alternating current side of the energy storage converter, U represents the voltage amplitude of the alternating current side of the energy storage converter, U _{W} represents the voltage of the gridconnected point, delta represents the phase angle of the alternating current side of the energy storage converter, delta _{W} represents the phase angle of the gridconnected point, and X _{W} represents the reactance of a line between the energy storage converter and the gridconnected point;
S12, enabling the difference value between the phase angle of the gridconnected point and the phase angle of the alternating current side of the energy storage converters to be smaller than a preset phase angle difference threshold value, and obtaining an active power phase angle correlation model and a reactive power amplitude correlation model based on active power and reactive power output to the gridconnected point by the alternating current side of each energy storage converter;
the calculation expressions of the active power phasor correlation model and the reactive power voltage amplitude correlation model are respectively as follows:
，
；
s13, constructing a sagging control model based on the active power phase angle correlation model and the reactive power amplitude correlation model;
the computational expression of the droop control model is as follows:
，
Wherein m represents a phase angle control parameter, δ _{e} represents a rated phase angle, P _{e} represents a rated active power, n represents an amplitude control parameter, U _{e} represents a rated voltage amplitude, and Q _{e} represents a rated reactive power.
3. The power distribution method based on the distributed energy storage converter integrated system according to claim 2, wherein the step S2 includes the steps of:
s21, constructing a gridconnected point phase angle difference model based on active power output to the gridconnected point by the output side of each energy storage converter;
The calculation expression of the gridconnected point phase angle difference model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{i} represents a phase angle of the ac side of the ith parallel energy storage converter, δ _{j} represents a phase angle of the ac side of the jth parallel energy storage converter, P _{i} represents an active power output from the ac side of the ith parallel energy storage converter to the gridconnected point, P _{j} represents an active power output from the ac side of the jth parallel energy storage converter to the gridconnected point, ω represents an angular frequency, L _{i} represents an output inductance corresponding to the ac side of the ith parallel energy storage converter, U _{i} represents a voltage amplitude of the ac side of the ith energy storage converter, L _{Di} represents a line inductance corresponding to the jth parallel energy storage converter, L _{j} represents a voltage amplitude of the ac side of the jth parallel energy storage converter, L _{Dj} represents a line inductance in the jth energy storage converter module, wherein i, j=1, 2, …, N, and i+noteq, N are the total number of energy storage converter modules;
S22, constructing a sagging model of the parallel energy storage converter based on the sagging control model;
The calculation expression of the sagging model of the parallel energy storage converter is as follows:
，
，
Wherein δ _{ei} represents a rated droop phase angle corresponding to the ith parallel energy storage converter, m _{i} represents a phase angle control parameter corresponding to the ith parallel energy storage converter, P _{ei} represents a rated active power corresponding to the ith parallel energy storage converter, δ _{ej} represents a rated droop phase angle corresponding to the jth parallel energy storage converter, m _{j} represents a phase angle control parameter corresponding to the jth parallel energy storage converter, and P _{ej} represents a rated active power corresponding to the jth parallel energy storage converter;
s23, constructing a phase angle difference model of the parallel energy storage converter based on a gridconnected point phase angle difference model and a sagging model of the parallel energy storage converter;
the calculation expression of the phase angle difference model of the parallel energy storage converter is as follows:
，
。
4. The distributed energy storage converter integration systembased power distribution method according to claim 3, wherein the calculation expression of the phase angle power correlation model of the parallel energy storage converter is as follows:
，
wherein, & represents and P _{L} represents the total power of the energy storage converters connected in parallel.
5. The method for power distribution based on a distributed energy storage converter integration system according to claim 4, wherein S4 comprises the steps of:
s41, obtaining an active power ratio model of the parallel energy storage converter based on a phase angle power correlation model of the parallel energy storage converter;
the calculation expression of the active power ratio model of the parallel energy storage converter is as follows:
；
s42, based on an active power ratio model of the parallel energy storage converter, combining highresistance lowinductance characteristics of a power distribution network line to obtain a fuzzy active power ratio model of the parallel energy storage converter;
The calculation expression of the fuzzy active power ratio model of the parallel energy storage converter is as follows:
。
6. The distributed energy storage converter integration systembased power distribution method according to claim 5, wherein the calculation expression of the output power distribution model of the parallel energy storage converters is as follows:
Wherein P _{1} represents the active power output from the ac side of the 1 st parallel energy storage converter to the gridconnected point, m _{1} represents the phase angle control parameter corresponding to the 1 st parallel energy storage converter, P _{2} represents the active power output from the ac side of the 2 nd parallel energy storage converter to the gridconnected point, m _{2} represents the phase angle control parameter corresponding to the 2 nd parallel energy storage converter, P _{k} represents the active power output from the ac side of the k parallel energy storage converter to the gridconnected point, m _{k} represents the phase angle control parameter corresponding to the k parallel energy storage converter, P _{N} represents the active power output from the ac side of the N parallel energy storage converter to the gridconnected point, m _{N} represents the phase angle control parameter corresponding to the N parallel energy storage converter, P _{e1} represents the rated active power corresponding to the 1 st parallel energy storage converter, P _{e2} represents the rated active power corresponding to the 2 nd parallel energy storage converter, P _{ek} represents the active power corresponding to the k parallel energy storage converter, P _{eN} represents the rated active power corresponding to the N energy storage converter, wherein n=1, n=98.
7. The distributed energy storage converter integration systembased power distribution method according to claim 6, wherein the calculation expression of the target power model of the parallel energy storage converter is as follows:
Wherein P _{target} represents the converter integration target power.
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