CN106230012A - Ultracapacitor and the Optimal Configuration Method of accumulator capacity in grid-connected photovoltaic system - Google Patents

Abstract

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in a kind of grid-connected photovoltaic system, described method utilizes two two way convertors respectively bank of super capacitors and accumulator battery to be carried out charge and discharge control, Life cycle cost according to ultracapacitor, accumulator and current transformer, utilize particle cluster algorithm to obtain ultracapacitor and the Economic capacity (configuration group number) of accumulator meeting the storage of uneven photovoltaic electric energy and release request, thus realize distributing rationally of ultracapacitor and accumulator capacity.The present invention takes into full account the method for operation and the cost of current transformer, participate in the optimization calculating of mixed energy storage system configuration capacity as independent individuality, consider the constraints of ultracapacitor, accumulator and current transformer simultaneously, make result of calculation more scientific and reasonable.The method is ensureing that photovoltaic generating system is efficiently, while stable operation, be effectively increased the economy of electricity generation system.

Description

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in grid-connected photovoltaic system

Technical field

The present invention relates to a kind of grid-connected photovoltaic system that is applicable to, it is considered to the ultracapacitor-accumulator of current transformer impact The Optimal Configuration Method of capacity, belongs to technical field of power generation.

Background technology

The renewable energy system output-power fluctuations such as photovoltaic are big, can produce a series of asking in its running Topic, as caused, operation of power networks is unstable, power quality is poor, participate in dispatching of power netwoks difficulty etc..Add energy storage dress in systems Putting and can effectively solve the problems referred to above, the mixed energy storage system being made up of ultracapacitor and accumulator is high-performance, low cost The optimum form of the composition of energy-storage system, it key challenge is how to carry out distributing rationally of capacity.

Battery technology is ripe, dependable performance, but cycle life is short, and frequent high-power low capacity discharge and recharge can greatly be contracted The service life of short accumulator.And ultracapacitor has extended cycle life, power density is big, charge/discharge rates is fast.Ultracapacitor Combine with accumulator and can form mixed energy storage system, coordinate charge and discharge control by electronic power convertor, super Capacitor undertakes high frequency power part, and accumulator is responsible for low frequency power part, so can realize ultracapacitor and accumulator Mutual supplement with each other's advantages, ensureing while the quality of power supply, the overall performance of energy-storage system can improved, extend energy-storage system and run year Limit.

Current transformer is indispensable vitals in energy-storage system, and the overall cost of ownership of mixed energy storage system should include The acquisition cost of current transformer, operating cost and cost of disposal.But existing mixed energy storage system capacity collocation method does not has mostly Have and the impact of current transformer is taken into account, or simply broadly the cost of current transformer is included in ultracapacitor or electric power storage Among pond, and major part is according to engineering experience, and scientific theory is based on insufficient grounds, and therefore cannot ensure the reasonability that system configures And economy.

Summary of the invention

Present invention aims to the drawback of prior art, it is provided that in a kind of grid-connected photovoltaic system ultracapacitor with The Optimal Configuration Method of accumulator capacity, is ensureing that photovoltaic generating system is efficiently, while stable operation, improve electricity generation system Operational efficiency and economy.

Purpose of the present invention realizes with following technical proposals:

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in a kind of grid-connected photovoltaic system, described method utilizes two Individual two way convertor carries out charge and discharge control to bank of super capacitors and accumulator battery respectively, according to ultracapacitor, accumulator With the Life cycle cost of current transformer, utilize particle cluster algorithm to obtain and meet uneven photovoltaic electric energy storage and release request The Economic capacity (configuration group number) of ultracapacitor and accumulator, thus realize the excellent of ultracapacitor and accumulator capacity Change configuration.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in above-mentioned grid-connected photovoltaic system, described method is by following Step is carried out:

A. photovoltaic plant exemplary operation day generated output and uneven merit between load power, grid-connected power on the spot are obtained Rate performance data；

B. mixed energy storage system charge-discharge electric power performance data is carried out empirical mode decomposition, obtain high frequency power component and Low frequency power component；

C. by the cost of high frequency power component maximum value calculation capacitance convertor, by low frequency power component maximum value calculation electricity The cost of pond current transformer；

D. set up the mixed energy storage system capacity configuration comprising capacitance convertor cost and battery inverter cost and optimize mesh Scalar functions:

MinC=C_sc+C_ba+C₁+C₂

Wherein C_sc、C_ba、C₁、C₂It is respectively ultracapacitor, accumulator, capacitance convertor and the assembly of battery inverter This, expression formula is:

$\left\{\begin{array}{c}{C}_{sc}=k_{sc}\×n\×f_{sc}\×(1+{\mathrm{\η}}_{sc}+{\mathrm{\μ}}_{sc})\\ C_{ba}=k_{ba}\×m\×f_{ba}\×(1+{\mathrm{\η}}_{ba}+{\mathrm{\λ}}_{ba}+{\mathrm{\μ}}_{ba})\\ C_1=k_1\×l_1\×f_1\×(1+{\mathrm{\η}}_1+{\mathrm{\μ}}_1)\\ C_2=k_2\×l_2\×f_2\×(1+{\mathrm{\η}}_2+{\mathrm{\μ}}_2)\end{array}\right.$

In formula, m, n are respectively the group number of accumulator and ultracapacitor, l₁And l₂It is respectively capacitance convertor and battery unsteady flow The power cell number of device, k_sc、k_ba、k₁And k₂It is respectively ultracapacitor, accumulator, capacitance convertor and battery inverter Allowance for depreciation, f_sc、f_ba、f₁And f₂It is respectively ultracapacitor, accumulator, capacitance convertor and the unit price of battery inverter, η_sc、 η_ba、η₁And η₂It is respectively ultracapacitor, accumulator, capacitance convertor and the operating cost coefficient of battery inverter, λ_baFor storing The maintenance cost coefficient of battery, μ_sc、μ_ba、μ₁And μ₂It is respectively ultracapacitor, accumulator, capacitance convertor and battery inverter Cost of disposal coefficient；

The constraints of accumulator:

$\left\{\begin{array}{c}{P}_{bamin}\≤P_{ba}\left(t\right)\≤P_{bamax}\\ E_{ba\min }\≤E_{ba}\left(t\right)\≤E_{bamax}\\ {\mathrm{SOC}}_{\min }\≤SOC\left(t\right)\≤{\mathrm{SOC}}_{max}\end{array}\right.$

The constraints of ultracapacitor:

$\left\{\begin{array}{c}{P}_{scm\stackrel{\·}{t}n}\≤P_{sc}\left(t\right)\≤P_{scmax}\\ E_{sc\min }\≤E_{sc}\left(t\right)\≤E_{scmax}\\ V_{sc\min }\≤V_{sc}\left(t\right)\≤V_{sc\max }\end{array}\right.$

The constraints of current transformer:

$\left\{\begin{array}{c}{P}_1\left(t\right)\≤P_{1max}\\ T_1\left(t\right)\≤T_{1max}\end{array}\right.$

$\left\{\begin{array}{c}{P}_2\left(t\right)\≤P_{2max}\\ T_2\left(t\right)\≤T_{2max}\end{array}\right.$

P in formula_ba、P_scIt is respectively accumulator and the charge-discharge electric power of ultracapacitor, P_bamin、P_scminIt is respectively accumulator Minimum power with ultracapacitor discharge and recharge；P_bamax、P_scmaxIt is respectively accumulator and the maximum work of ultracapacitor discharge and recharge Rate；E_ba(t)、E_scT () is respectively t accumulator and the energy of ultracapacitor, E_bamin、E_scminIt is respectively accumulator and surpasses The minima that level capacitor energy limits；E_bamax、E_scmaxIt is respectively accumulator and the maximum of super capacitor energy restriction； SOC (t) is the state-of-charge of t accumulator, SOC_min、SOC_maxIt is respectively state-of-charge minimum and maximum value；V_scT () is t The voltage of moment ultracapacitor, V_scmin、V_scmaxVoltage for ultracapacitor limits minimum and maximum value；P₁(t)、P₂(t) It is respectively t by capacitance convertor and the general power of battery inverter, P_1max、P_2maxIt is respectively capacitance convertor and battery Current transformer allows to come and go the general power maximum passed through, T₁(t)、T₂T () is respectively t capacitance convertor and battery inverter Temperature, T_1max、T_2maxThe maximum temperature that can bear for capacitance convertor and battery inverter；

E. utilize particle cluster algorithm that object function is carried out optimizing, it is thus achieved that ultracapacitor that cost is minimum and electric power storage Pond optimal allocation capacity.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in above-mentioned grid-connected photovoltaic system, each parts allowance for depreciation Computational methods are as follows:

The allowance for depreciation of accumulator is k_ba=N_e/N_ba, wherein N_e=N_DOD*l_DOD, l in formula_DODFor the depth of discharge of accumulator, N_DODFor the charge and discharge cycles number of times of accumulator, N_baIt is 100% charge and discharge circulation life number of times, N_eCharge and discharge cycles for equivalence Number of times；

The allowance for depreciation of ultracapacitor is k_sc=N/N_sc, N in formula_scFor ultracapacitor from E_scmaxTo E_scminDischarge and recharge Cycle life number of times, N is actual charge and discharge cycles number of times；

The allowance for depreciation of capacitance convertor and battery inverter is replaced by respective fatigue damage degree, fatigue damage degree D Computing formula is D=n/N, and in formula, N is temperature or the Life Cycle number of times of power of current transformer, and n is the reality of temperature or power Cycle-index.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity, being manipulated so of accumulator in above-mentioned grid-connected photovoltaic system This coefficient is calculated by following formula:

${\mathrm{\μ}}_{ba}=\frac{k_{ba}\×{(1+k_{ba})}^n}{{(1+k_{ba})}^n-1}$

In formula, n is accumulator cell charging and discharging number of times.

The present invention takes into full account the method for operation and the cost of current transformer, participates in hybrid energy-storing as independent individuality During the optimization of system configuration capacity calculates, consider the constraints of ultracapacitor, accumulator and current transformer simultaneously, make calculating tie Fruit is more scientific and reasonable.The method is ensureing that photovoltaic generating system is efficiently, while stable operation, be effectively increased electricity generation system Economy.

Accompanying drawing explanation

Fig. 1 is grid-connected photovoltaic system general structure figure；

Fig. 2 is capacitance convertor and battery inverter cost acquisition flow chart；

Fig. 3 is the optimization calculation flow chart of the present invention.

Figure with each symbol in literary composition is: C_sc、C_ba、C₁、C₂It is respectively ultracapacitor, accumulator, capacitance convertor and electricity The totle drilling cost of pond current transformer, l₁And l₂It is respectively capacitance convertor and the power cell number of battery inverter, k_sc、k_ba、k₁And k₂ It is respectively ultracapacitor, accumulator, capacitance convertor and the allowance for depreciation of battery inverter, f_sc、f_ba、f₁And f₂The most super The unit price of capacitor, accumulator, capacitance convertor and battery inverter, η_sc、η_ba、η₁And η₂It is respectively ultracapacitor, electric power storage The operating cost coefficient of pond, capacitance convertor and battery inverter, λ_baFor the maintenance cost coefficient of accumulator, μ_sc、μ_ba、μ₁And μ₂ It is respectively ultracapacitor, accumulator, capacitance convertor and the cost of disposal coefficient of battery inverter, P_bamin、P_scminIt is respectively Accumulator and the minimum power of ultracapacitor discharge and recharge；P_bamax、P_scmaxIt is respectively accumulator and ultracapacitor discharge and recharge Peak power；E_ba(t)、E_scT () is respectively t accumulator and the energy of ultracapacitor, E_bamin、E_scminIt is respectively electric power storage The minima that pond and super capacitor energy limit；E_bamax、E_scmaxIt is respectively accumulator and super capacitor energy limits Big value；P₁(t)、P₂T () is respectively t by capacitance convertor and the general power of battery inverter, P_1max、P_2maxIt is respectively Capacitance convertor and battery inverter allow to come and go the general power maximum passed through, T₁(t)、T₂T () is respectively t electric capacity and becomes Stream device and the temperature of battery inverter, T_1max、T_2maxThe maximum temperature that can bear for capacitance convertor and battery inverter, P_pv For photo-voltaic power supply output, P_GridFor grid-connected power, P_LoadFor load power, P_HThe high frequency power component obtained for decomposition, P_L For low frequency power component, P_HmaxFor HFS power maximum, P_LmaxFor low frequency part power maximum, SOC (t) is t The state-of-charge of accumulator, SOC_min、SOC_maxIt is respectively state-of-charge minimum and maximum value；V_scT () is t ultracapacitor Voltage, V_scmin、V_scmaxVoltage for ultracapacitor limits minimum and maximum value；E_baFor in accumulator storage energy, E_ba0For accumulator primary power, E_scFor the energy of storage, E in ultracapacitor_sc0For ultracapacitor primary power, P_baFor Accumulator battery charge-discharge electric power, P_scFor bank of super capacitors charge-discharge electric power, l_DODFor the depth of discharge of accumulator, N_DODFor electric power storage The charge and discharge cycles number of times in pond, N_baIt is 100% charge and discharge circulation life number of times, N_eCharge and discharge cycles number of times for equivalence；N_scFor Ultracapacitor is from E_scmaxTo E_scminCharge and discharge circulation life number of times, D is fatigue damage degree, and V (t) is ultracapacitor Initial voltage.

Detailed description of the invention

The invention will be further described below in conjunction with the accompanying drawings.

The present invention is more than considering ultracapacitor and the cost of accumulator, simultaneously using current transformer as with ultracapacitor The ingredient same with accumulator, is included in mixed energy storage system assembly by its acquisition cost, operating cost and cost of disposal In this calculating.

As it is shown in figure 1, it is constituted, grid-connected photovoltaic system general structure includes that photovoltaic generating system, electrical network, alternating current-direct current are negative Lotus, bank of super capacitors, accumulator battery, two-way DC/DC capacitance convertor, two-way DC/DC battery inverter, unidirectional DC/DC connect Mouth circuit, DC/AC inverter, DC/AC combining inverter.Dotted box portion therein is mixed energy storage system, mainly includes surpassing Level capacitor, accumulator, capacitance convertor and battery inverter four part.When system is run, photo-voltaic power supply output is P_PV； DC load and AC load power are P on the spot_Load；The grid-connected power being transported to electrical network by combining inverter is P_Grid；Mixing The power of energy-storage system storage (or release) is P_HESS, the high frequency power component being responsible for including ultracapacitor and accumulator The low frequency power component being responsible for.

Current transformer 1 and current transformer 2 cost calculation step are as shown in Figure 2.First according to generated output, load power and grid-connected Power is determined need to be by the general power of mixed energy storage system discharge and recharge, and this general power, through empirical mode decomposition method, obtains height Frequency and low frequency power component, the peak power then according to high and low frequency determines that the power cell of current transformer 1 and current transformer 2 is individual The relevant parameters such as number, thus calculate current transformer 1 and the cost of current transformer 2 according to these parameters.

The flow process that ultracapacitor and accumulator capacity are distributed rationally is as shown in Figure 3.First ultracapacitor and storage are obtained The original state parameter (voltage of ultracapacitor and the state-of-charge of accumulator) of battery, obtains photovoltaic generation power, on the spot Load power and grid-connected power data, and determine need to be carried out discharge and recharge by mixed energy storage system according to these three power data General power, this general power finds boundary frequency through empirical mode decomposition, thus general power is decomposed into high frequency power component and Low frequency power component, is determined current transformer 1 and the merit of current transformer 2 by high frequency power component maximum and low frequency power component maximum Rate unit number, thus calculate current transformer 1 and the cost of current transformer 2, the high frequency power component simultaneously decomposited is according to super electricity The voltage status of container carries out discharge and recharge or abandons discharge and recharge, and same low frequency power component is determined according to the state-of-charge of accumulator Determine discharge and recharge or abandon discharge and recharge, calculating both become finally according to the actual charge status of ultracapacitor and accumulator This, so totle drilling cost is ultracapacitor, accumulator, current transformer 1 and the summation of current transformer 2 cost, fall into a trap in Life cycle Calculate totle drilling cost, thus ultracapacitor and accumulator are optimized configuration.

The target of mixed energy storage system capacity optimization is, according to ultracapacitor, accumulator and the full Life Cycle of current transformer Current cost, utilizes particle cluster algorithm to obtain and meets uneven photovoltaic electric energy storage and the ultracapacitor of release request and accumulator Economic capacity (configuration group number).

Described method follows the steps below:

A. photovoltaic plant exemplary operation day generated output and uneven merit between load power, grid-connected power on the spot are obtained Rate performance data.For the photovoltaic plant built up, the detection equipment utilizing power station itself to configure obtains photovoltaic generation power；For The photovoltaic plant do not built up is then according to situation prediction at sunshine generated output.If known load on the spot, then can be according to specifically making By situation, measure with power meter；If load does not put into, then the method using load power prediction.Grid-connected power is root Obtain according to the grid-connected interconnection agreement power of dispatching of power netwoks agencies dictate

B. mixed energy storage system charge-discharge electric power performance data is carried out empirical mode decomposition, obtain high frequency power component and Low frequency power component.Empirical mode decomposition (EMD) and Hilbert spectrum analysis combine to Non-stationary nonlinear signal analysis Good effect can be reached.EMD carries out signal decomposition according to the time scale of self, decomposes through EMD, and imbalance power is divided Solve as a series of intrinsic mode function c_i, and c_iFrequency be gradually lowered with the increase of i, after empirical mode decomposition utilize Hilbert frequency spectrum obtains instantaneous frequency time graph.

Obtain high frequency power component and low frequency power component: obtain from empirical mode decomposition and Hilbert frequency spectrum these Curve is found boundary frequency f_g, the general power of mixed energy storage system is divided into high and low frequency two parts.Frequency is higher than f_gHeight Frequently power component is designated as P_H, frequency is less than f_gLow frequency component be designated as P_L.Computing formula P_H=c₁+c₂+...+c_g(1), P_L=c_g+1+ c_g+2+…+c_m(2).The principle selecting boundary frequency is f_gOverlapping few with two mode of next-door neighbour.Boundary frequency herein and tradition Define identical.

C. by the cost of high frequency power component maximum value calculation capacitance convertor, the maximum according to high frequency power component is true The configuration parameters such as the power cell number of the capacitance convertor that surely need to configure, according to the cost of these parameter determination current transformers 1.Press The cost of low frequency power component maximum value calculation battery inverter；Equally, need are gone out according to the maximum value calculation of low frequency component power Want the configuration parameter such as power cell number of battery inverter, calculate the cost of current transformer 2 according to these parameters.

D. set up the mixed energy storage system capacity configuration comprising capacitance convertor cost and battery inverter cost and optimize mesh Scalar functions.

1. the object function that hybrid energy-storing capacity is distributed rationally is

MinC=C_sc+C_ba+C₁+C₂ (1)

C_sc、C_ba、C₁、C₂It is respectively ultracapacitor, accumulator, capacitance convertor and the totle drilling cost of battery inverter.Its Middle totle drilling cost includes acquisition cost, maintenance cost, operating cost and cost of disposal.

$\left\{\begin{array}{c}{C}_{sc}=k_{sc}\×n\×f_{sc}\×(1+{\mathrm{\η}}_{sc}+{\mathrm{\μ}}_{sc})\\ C_{ba}=k_{ba}\×m\×f_{ba}\×(1+{\mathrm{\η}}_{ba}+{\mathrm{\λ}}_{ba}+{\mathrm{\μ}}_{ba})\\ C_1=k_1\×l_1\×f_1\×(1+{\mathrm{\η}}_1+{\mathrm{\μ}}_1)\\ C_2=k_2\×l_2\×f_2\×(1+{\mathrm{\η}}_2+{\mathrm{\μ}}_2)\end{array}\right.---\left(2\right)$

M, n are respectively the group number of accumulator and ultracapacitor, l₁And l₂It is respectively capacitance convertor and battery inverter Power cell number, k_sc、k_ba、k₁And k₂It is respectively ultracapacitor, accumulator, capacitance convertor and the depreciation of battery inverter Rate, f_sc、f_ba、f₁And f₂It is respectively ultracapacitor, accumulator, capacitance convertor and the unit price of battery inverter, η_sc、η_ba、η₁ And η₂It is respectively ultracapacitor, accumulator, capacitance convertor and the operating cost coefficient of battery inverter, λ_baFor accumulator Maintenance cost coefficient, μ_sc、μ_ba、μ₁And μ₂It is respectively ultracapacitor, accumulator, capacitance convertor and the disposal of battery inverter Cost coefficient.

2. the calculating of allowance for depreciation

The depreciation process of accumulator can be represented by its capacitance loss degree, and some researchs show, the appearance of accumulator Amount loss and depth of discharge l_DODLinear.During so specifically calculating its depreciation value, can be first by the charge and discharge of different depth of discharges Electricity cycle-index N_DODConversion is the charge and discharge cycles times N of equivalence_e.Convert formula is represented by N_e=N_DOD*l_DODIf: accumulator Carry out l_DOD=100% charge and discharge circulation life number of times is N_ba, then the depreciation value of accumulator is k_ba=N_e/N_ba。

The depreciation value of ultracapacitor can direct cycle-index calculate.If ultracapacitor is carried out from E_scmaxArrive E_scminThe number of times of charge and discharge cycles be N_sc, then after carrying out n times charge and discharge cycles, its depreciation value is represented by: k_sc=N/ N_sc。

The thermal and mechanical stress that the fatigue failure of current transformer is mainly produced by long temperature or power cycle causes, this In utilize the fatigue damage of current transformer to replace depreciation value.If the life-span of current transformer is n times, it is assumed that at the work of certain permanent width stress S Under with, have passed through the circulation of n secondary stress, then injury tolerance is D=n/N, i.e. k₁=n₁/N₁, k₂=n₂/N₂.The current transformer of accumulator side The depreciation value of depreciation value and ultracapacitor side is different.

3. the calculating of other coefficients

The operating factor of accumulator, ultracapacitor and three kinds of equipment of current transformer be rule of thumb summed up about Value, ultracapacitor can be non-maintaining, so need not calculate its maintenance cost coefficient, i.e. η_sc=0, same current transformer is running In almost also without maintenance, the when of being all end-of-life when typically need to safeguard, so η₁=0, η₂=0.The disposal of accumulator Coefficient:

4. constraints

The constraints of accumulator:

$\left\{\begin{array}{c}{P}_{bamin}\≤P_{ba}\left(t\right)\≤P_{bamax}\\ E_{ba\min }\≤E_{ba}\left(t\right)\≤E_{bamax}\\ {\mathrm{SOC}}_{\min }\≤SOC\left(t\right)\≤{\mathrm{SOC}}_{max}\end{array}\right.---\left(3\right)$

The constraints of ultracapacitor:

$\left\{\begin{array}{c}{P}_{scmin}\≤P_{sc}\left(t\right)\≤P_{scmax}\\ E_{sc\min }\≤E_{sc}\left(t\right)\≤E_{scmax}\\ V_{sc\min }\≤V_{sc}\left(t\right)\≤V_{sc\max }\end{array}\right.---\left(4\right)$

The constraints of current transformer:

$\left\{\begin{array}{c}{P}_1\left(t\right)\≤P_{1\max }\\ T_1\left(t\right)\≤T_{1max}\end{array}\right.---\left(5\right)$

$\left\{\begin{array}{c}{P}_2\left(t\right)\≤P_{2\max }\\ T_2\left(t\right)\≤T_{2max}\end{array}\right.---\left(6\right)$

In formula, P_ba、P_scIt is respectively accumulator and the charge-discharge electric power of ultracapacitor, P_bamin、P_scminIt is respectively accumulator Minimum power with ultracapacitor discharge and recharge；P_bamax、P_scmaxIt is respectively accumulator and the maximum work of ultracapacitor discharge and recharge Rate；E_ba(t)、E_scT () is respectively t accumulator and the energy of ultracapacitor, E_bamin、E_scminIt is respectively accumulator and surpasses The minima that level capacitor energy limits；E_bamax、E_scmaxIt is respectively accumulator and the maximum of super capacitor energy restriction； SOC (t) is the state-of-charge of t accumulator, SOC_min、SOC_maxIt is respectively state-of-charge minimum and maximum value；V_scT () is t The voltage of moment ultracapacitor, V_scmin、V_scmaxVoltage for ultracapacitor limits minimum and maximum value；P₁(t)、P₂(t) It is respectively t by capacitance convertor and the general power of battery inverter, P_1max、P_2maxIt is respectively capacitance convertor and battery Current transformer allows to come and go the general power maximum passed through, T₁(t)、T₂T () is respectively t capacitance convertor and battery inverter Temperature, T_1max、T_2maxThe maximum temperature that can bear for capacitance convertor and battery inverter.

E. utilize particle cluster algorithm that described object function is carried out optimizing, it is thus achieved that the minimum ultracapacitor of cost and Accumulator optimal allocation capacity.

The present invention had both considered the cost of ultracapacitor and accumulator, it is also considered that vital electricity in system operation Hold current transformer and the cost of battery inverter so that optimize result of calculation more reasonable.Super according to the configuration of this optimization result of calculation Capacitor, accumulator, capacitance convertor and battery inverter, may be constructed low cost, performance hybrid energy-storing system strong, long-life System, with ensure photovoltaic generating system efficiently, stable electric generation runs.

Claims (4)

1. ultracapacitor and an Optimal Configuration Method for accumulator capacity in grid-connected photovoltaic system, is characterized in that, described side Method utilizes two two way convertors respectively bank of super capacitors and accumulator battery to be carried out charge and discharge control, according to super capacitor The Life cycle cost of device, accumulator and current transformer, utilize particle cluster algorithm obtain meet the storage of uneven photovoltaic electric energy with The ultracapacitor of release request and the Economic capacity (configuration group number) of accumulator, thus realize ultracapacitor and electric power storage Distributing rationally of tankage.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in grid-connected photovoltaic system the most according to claim 1, It is characterized in that, said method comprising the steps of:

A. obtain photovoltaic plant exemplary operation day generated output and on the spot imbalance power between load power, grid-connected power special Property data；

B. mixed energy storage system charge-discharge electric power performance data is carried out empirical mode decomposition, obtains high frequency power component and low frequency Power component；

C. by the cost of high frequency power component maximum value calculation capacitance convertor, become by low frequency power component maximum value calculation battery The cost of stream device；

D. the mixed energy storage system capacity configuration optimization aim letter comprising capacitance convertor cost and battery inverter cost is set up Number:

MinC=C_sc+C_ba+C₁+C₂

Wherein C_sc、C_ba、C₁、C₂It is respectively ultracapacitor, accumulator, capacitance convertor and the totle drilling cost of battery inverter, table Reaching formula is:

$\left\{\begin{array}{c}{C}_{sc}=k_{sc}\×n\×f_{sc}\×(1+{\mathrm{\η}}_{sc}+{\mathrm{\μ}}_{sc})\\ C_{ba}=k_{ba}\×m\×f_{ba}\×(1+{\mathrm{\η}}_{ba}+{\mathrm{\λ}}_{ba}+{\mathrm{\μ}}_{ba})\\ C_1=k_1\×l_1\×f_1\×(1+{\mathrm{\η}}_1+{\mathrm{\μ}}_1)\\ C_2=k_2\×l_2\×f_2\×(1+{\mathrm{\η}}_2+{\mathrm{\μ}}_2)\end{array}\right.$

In formula, m, n are respectively the group number of accumulator and ultracapacitor, l₁And l₂It is respectively capacitance convertor and battery inverter Power cell number, k_sc、k_ba、k₁And k₂It is respectively ultracapacitor, accumulator, capacitance convertor and the depreciation of battery inverter Rate, f_sc、f_ba、f₁And f₂It is respectively ultracapacitor, accumulator, capacitance convertor and the unit price of battery inverter, η_sc、η_ba、η₁ And η₂It is respectively ultracapacitor, accumulator, capacitance convertor and the operating cost coefficient of battery inverter, λ_baFor accumulator Maintenance cost coefficient, μ_sc、μ_ba、μ₁And μ₂It is respectively ultracapacitor, accumulator, capacitance convertor and the disposal of battery inverter Cost coefficient；

The constraints of accumulator:

$\left\{\begin{array}{c}{P}_{bamin}\≤P_{ba}\left(t\right)\≤P_{bamax}\\ E_{ba\min }\≤E_{ba}\left(t\right)\≤E_{bamax}\\ {\mathrm{SOC}}_{\min }\≤SOC\left(t\right)\≤{\mathrm{SOC}}_{max}\end{array}\right.$

The constraints of ultracapacitor:

$\left\{\begin{array}{c}{P}_{sc\min }\≤P_{sc}\left(t\right)\≤P_{scmax}\\ E_{sc\min }\≤E_{sc}\left(t\right)\≤E_{scmax}\\ V_{sc\min }\≤V_{sc}\left(t\right)\≤V_{sc\max }\end{array}\right.$

The constraints of current transformer:

$\left\{\begin{array}{c}{P}_1\left(t\right)\≤P_{1max}\\ T_1\left(t\right)\≤T_{1max}\end{array}\right.$

$\left\{\begin{array}{c}{P}_2\left(t\right)\≤P_{2max}\\ T_2\left(t\right)\≤T_{2\max }\end{array}\right.$

P in formula_ba、P_scIt is respectively accumulator and the charge-discharge electric power of ultracapacitor, P_bamin、P_scminIt is respectively accumulator and surpasses The minimum power of level capacitor charging/discharging；P_bamax、P_scmaxIt is respectively accumulator and the peak power of ultracapacitor discharge and recharge； E_ba(t)、E_scT () is respectively t accumulator and the energy of ultracapacitor, E_bamin、E_scminIt is respectively accumulator and super electricity The minima that container energy limits；E_bamax、E_scmaxIt is respectively accumulator and the maximum of super capacitor energy restriction；SOC T () is the state-of-charge of t accumulator, SOC_min、SOC_maxIt is respectively state-of-charge minimum and maximum value；V_scT () is t The voltage of ultracapacitor, V_scmin、V_scmaxVoltage for ultracapacitor limits minimum and maximum value；P₁(t)、P₂(t) difference For t by capacitance convertor and the general power of battery inverter, P_1max、P_2maxIt is respectively capacitance convertor and battery unsteady flow Device allows to come and go the general power maximum passed through, T₁(t)、T₂T () is respectively t capacitance convertor and the temperature of battery inverter Degree, T_1max、T_2maxThe maximum temperature that can bear for capacitance convertor and battery inverter；

E. utilize particle cluster algorithm that object function is carried out optimizing, it is thus achieved that ultracapacitor that cost is minimum and accumulator are Excellent configuration capacity.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in grid-connected photovoltaic system the most according to claim 2, It is characterized in that, the computational methods of each parts allowance for depreciation are as follows:

The allowance for depreciation of accumulator is k_ba=N_e/N_ba, wherein N_e=N_DOD*l_DOD, l in formula_DODFor the depth of discharge of accumulator, N_DODFor The charge and discharge cycles number of times of accumulator, N_baIt is 100% charge and discharge circulation life number of times, N_eCharge and discharge cycles number of times for equivalence；

The allowance for depreciation of ultracapacitor is k_sc=N/N_sc, N in formula_scFor ultracapacitor from E_scmaxTo E_scminCharge and discharge cycles Life-span number of times, N is actual charge and discharge cycles number of times；

The allowance for depreciation of capacitance convertor and battery inverter is replaced by respective fatigue damage degree, the calculating of fatigue damage degree D Formula is D=n/N, and in formula, N is temperature or the Life Cycle number of times of power of current transformer, and n is the actual cycle of temperature or power Number of times.

Ultracapacitor and the Optimal Configuration Method of accumulator capacity in grid-connected photovoltaic system the most according to claim 3, It is characterized in that, the cost of disposal coefficient of accumulator is calculated by following formula:

${\mathrm{\μ}}_{ba}=\frac{k_{ba}\×{(1+k_{ba})}^n}{{(1+k_{ba})}^n-1}$

In formula, n is accumulator cell charging and discharging number of times.