CN104134829B - Storage battery energy storage system control method - Google Patents

Abstract

The invention relates to a storage battery energy storage system control method which is technically characterized in that: reading the state of charge Soc (T) of current moment of a storage battery; according to a load forecasting result of the system in the next period of time delta t, estimating the exchange power Pex of the storage battery and the external within Delta t; according to the operating voltage of the storage battery system, calculating the exchange current Iex = Pex / U of the storage battery and the external within Delta t; if the exchange current Iex > 0, namely the storage battery is in discharging, performing the storage battery dischargeing control process, otherwise performing the storage battery charging control process. The storage battery energy storage system control method is reasonable in design, according to the electric quantity change situations in the storage battery in different charge and discharge current situations, optimization of the management and control of the storage battery energy storage system can be implemented, the energy conversion efficiency of the storage battery energy storage system can be effectively improved, the storage battery energy storage system control method can be widely used for energy management and control of energy storing devices of electric vehicle charging stations, micro networks or UPS systems.

Description

A kind of energy-storage system of accumulator control method

Technical field

The invention belongs to batteries to store energy control technology field, especially a kind of energy-storage system of accumulator control method.

Background technology

Accumulator is storage chemical energy a kind of electrochemical devices releasing electric energy when necessary.Its operation principle: Make internal active substance regeneration using outside electric energy during charging, be chemical energy electrical power storage, need during electric discharge again change Can be converted to electric energy output.The rated capacity of accumulator is used for characterizing the ability of its storage electric energy, when that is, accumulator is fully charged Internal electric energy, with the use of accumulator, its internal electric energy can constantly discharge.State-of-charge (state of charge, Soc) can be used to characterize the releasable degree of storage battery, state-of-charge refers to residual capacity and the rated capacity of accumulator Ratio, state-of-charge represents for 1 that accumulator electric-quantity is full up, and state-of-charge represents net discharge capacity for 0 and reaches rated capacity.

Due to being affected by internal electrochemical reaction process, the charge and discharge process of accumulator is subject to a series of constraints: right In charging process, it is not that the charging current of any size can be accepted by accumulator, there is a maximum acceptable electricity Stream, maximum acceptable size of current depends on the residual capacity of moment accumulator that charges；Meanwhile, maximum acceptable electric current Value in charging process for the size is not constant yet, and the increase with remaining battery capacity is reduced.For putting Electric process, the discharge capacity of accumulator is constrained by discharge current, and discharge current is bigger, the total electricity that accumulator can be released Fewer, the persistent period of discharge process is also shorter；Discharge current is less, and the total electricity that it can be released is bigger, discharges The persistent period of journey is also longer.

In energy-storage system of accumulator, in order to give full play to efficient energy conversion, need to set up energy management platform, to storage The discharge and recharge of battery is managed and controls.

Content of the invention

It is an object of the invention to overcoming the deficiencies in the prior art, provide a kind of reasonable in design and energy of can fully delivering The energy-storage system of accumulator control method of source transformation efficiency.

The present invention solves its technical problem and takes technical scheme below to realize:

A kind of energy-storage system of accumulator control method, comprises the following steps:

Step 1, state-of-charge soc (t) of reading current time accumulator；

Step 2, according to the load prediction results in system future a period of time δ t, in estimation δ t accumulator with outside Exchange power p_ex；

Step 3, according to battery system working voltage, calculate in δ t with outside exchanging electric current i_ex=p_ex/u；

If step 4 exchanging electric current i_ex＞ 0, represents battery discharging, execution step 5, otherwise execution step 6；

Step 5, battery discharging rate-determining steps；

Step 6, Battery charge controller step.

And, the concrete processing procedure of described step 5 is: in calculating δ t, accumulator maximum can discharge current i_outmaxIf, i_outmax≥i_ex, labelling accumulator can power, and the state-of-charge soc (t+ δ t) calculating accumulator after electric discharge is as reference；If i_outmax＜ i_ex, prompt system short of electricity warning information.

And, in described calculating δ t, accumulator maximum can discharge current i_outmaxUsing equation below:

$t=\frac{k\×\mathrm{soc}(t-1)}{i_{\mathrm{out}}^n}$

Wherein, soc (t-1) is the state-of-charge of electric discharge initial time accumulator, and t is the time of the sustainable electric discharge of accumulator T, k and n are the constant depending on different batteries self-discharge characteristic.

And, described calculate electric discharge after the state-of-charge of accumulator adopt equation below:

Wherein, t is in electric current i_outUnder the actual discharge time, c_nFor battery rating, soc (t) completes for electric discharge The state-of-charge of accumulator afterwards.

And, the concrete processing procedure of described step 6 is: the acceptable electric current of calculating accumulator and accumulator are when charging Between charging capacity c in t_in, charging current i_in＜ i₀, accumulator is with i_inConstant current charge；Otherwise, estimation accumulator is in δ t Critical charging current i of maximum_inmax, and control system is with i_inmaxCharge for accumulator, in prompt system, electric energy is superfluous simultaneously, Need cut-out power supply.

And, the acceptable electric current of described calculating accumulator adopts equation below:

I=i₀e^-at

Wherein, i₀For the maximum initial current value allowing when starting to charge up, α is that the charging of accumulator is subject to ratio for table The charging levying accumulator is subject to characteristic.

And, charging capacity c in charging interval t for the described calculating accumulator_inUsing equation below:

$c_{\mathrm{in}}=\left\{\begin{array}{cc}\frac{i_0}{\mathrm{\&alpha;}}(1-e^{-\mathrm{\&alpha;t}}),& i_{\mathrm{in}}\&greaterequal;i_0\\ i_{\mathrm{in}}t+\frac{i_{\mathrm{in}}}{{\mathrm{\&alpha;}}^{\&prime;}}(1-e^{-{\mathrm{\&alpha;}}^{\&prime;}(t-t)}),& i_{\mathrm{in}}<i_0,t<t\\ i_{\mathrm{in}}t,& i_{\mathrm{in}}<i_0,t\&greaterequal;t\end{array}\right.$

Wherein,i₀=α c_r,c_r=(1-soc (t-1)) cx, soc (t-1) are to fill The state-of-charge of accumulator, c before electricity_nRated capacity for energy storage.

And, described maximum critical charging current i_inmaxComputational methods be: order electric discharge simulation process in critical moment t =δ t, that is, $\mathrm{\&delta;t}=c_r/i_{\mathrm{in}\max }-i_{\mathrm{in}\max }/k_0^2,$ Thus being calculated $i_{\mathrm{in}\max }={-k}_0^2\mathrm{\&delta;t}\&plusminus;0.5\sqrt{k_0^4{\mathrm{\&delta;t}}^2+4k_0^2{c}_r},$ Take in this formula i_inmaxIt is the battery charging current under controlling for positive person.

And, described need cut-out power be (i_ex-i_inmax)u.

Advantages of the present invention and good effect are:

The present invention is reasonable in design, and it is real according to the electric quantity change situation of internal storage battery in the case of different charging and discharging currents Apply the optimum management to energy-storage system of accumulator and control, effectively improve the efficient energy conversion of energy-storage system of accumulator, can It is widely used in and energy management and control are carried out to the energy storage device in electric automobile charging station, microgrid or ups system.

Brief description

Fig. 1 is the first charged condition schematic diagram when accumulator charges；

Fig. 2 is second charged condition schematic diagram when accumulator charges；

Fig. 3 is the third charged condition schematic diagram when accumulator charges.

Specific embodiment

Below in conjunction with accompanying drawing, the present invention is further described:

A kind of energy-storage system of accumulator control method, comprises the following steps:

Step 1, state-of-charge soc (t) of reading current time accumulator；

Step 2, according to the load prediction results in system future a period of time δ t, in estimation δ t accumulator with outside Exchange power p_ex；

Step 3, according to battery system working voltage, calculate in δ t with outside exchanging electric current i_ex=p_ex/u；

If step 4 i_ex＞ 0, represents battery discharging, execution step 5, otherwise execution step 6；

Step 5, battery discharging processing procedure: can discharge current i according to accumulator maximum in formula (1) calculating δ t_outmax, If i_outmax≥i_ex, labelling accumulator can be powered, and calculate state-of-charge soc (the t+ δ of accumulator after electric discharge according to formula (2) T) as reference；If i_outmax＜ i_ex, prompt system short of electricity warning information.

In discharge process, the electric energy that accumulator can be released is constrained by discharge current, and discharge current is bigger, can put The capacity of electricity is fewer.If the state-of-charge of electric discharge initial time accumulator is soc (t-1), in the horizontal i of a certain discharge current_out Under, the time t of the sustainable electric discharge of accumulator can be with skin Kate (peukert) electric discharge formula description:

$t=\frac{k\&times;\mathrm{soc}(t-1)}{i_{\mathrm{out}}^n}---\left(1\right)$

Wherein, k and n is the constant depending on different batteries self-discharge characteristic, can be obtained by test.

According to above-mentioned principle, the discharge process emulation of accumulator can be expressed as:

Wherein, t is in electric current i_outUnder the actual discharge time, c_nFor battery rating, soc (t) completes for electric discharge The state-of-charge of accumulator afterwards, that is, after discharge off, the state-of-charge of accumulator is state-of-charge when terminating is (c_n×soc (t-1)-i_out×t)/c_n.

The control principle of discharge process: when with electric current i_outDuring continuous discharge, the discharge time that accumulator multipotency maintains is t.If actual discharge time t≤t, then after electric discharge terminates, the electricity that accumulator is released is c_n×soc(t-1)-i_out× t, puts State-of-charge after electricity terminates is (c_n×soc(t-1)-i_out×t)/c_n；If t >=t, accumulator cannot continue in time t With i_outLevel is discharged, and explanation cannot persistently supply electric power for specific load.

Step 6, accumulator charging procedure: belonged to according to the charging process that formula (3) and formula (4) calculate accumulator in δ t Which kind of situation in Fig. 1 to Fig. 3, if belonging to the third situation (Fig. 3), normal starting storage battery charge function；If Belong to first (Fig. 1) situation, two kinds of situations (Fig. 2), then according to Fig. 2 corresponding emulation expression formula estimation accumulator in δ t Critical greatly charging current i_inmax, and control system is with i_inmaxCharge for accumulator, in prompt system, electric energy is superfluous simultaneously, need Excise a part of power supply, need to excise power is (i_ex-i_inmax)u.i_inmaxComputational methods be: order electric discharge simulation process in facing Boundary moment t=δ t, that is, $\mathrm{\&delta;t}=c_r/i_{\mathrm{in}\max }-i_{\mathrm{in}\max }/k_0^2,$ Thus being calculated $i_{\mathrm{in}\max }={-k}_0^2\mathrm{\&delta;t}\&plusminus;0.5\sqrt{k_0^4{\mathrm{\&delta;t}}^2+4k_0^2{c}_r},$ Take this I in formula_inmaxIt is the battery charging current under controlling for positive person.

In charging process, be not that the charging current of any size can be accepted by accumulator, exist one maximum Acceptable electric current.Meanwhile, acceptable electric current also exponentially can decay with the charging interval it may be assumed that

I=i₀e^-at(3)

Wherein, i₀For the maximum initial current value allowing when starting to charge up, α is that the charging of accumulator is subject to ratio for table The charging levying accumulator is subject to characteristic.

Charging be subject to than with accumulator with i₀Capacity c to be charged when starting to charge up_rRelevant, according to Mace law (mass),k₀It is by testing the proportionality constant obtaining.During accepting current attenuation, charging is kept by than α Constant.Maximum initial charge current can be passed throughCalculate.

Accumulator charging procedure is as shown in Figure 1 to Figure 3.

Constant charge current i in Fig. 1 express time unit_inMore than i₀When situation, the now maximum acceptance of accumulator Electric current is only i₀And exponential damping.

In fig. 2, charging current i of initial time_in＜ i₀, accumulator can be with i_inConstant current charge.But it is certain to charge After time (less than t), with the minimizing of capacity to be charged, accumulator acceptable maximum initial charge current also drops therewith Low, when new maximum initial charge current i'₀It is reduced to equal to charging current i_inAfterwards, accept electric current and be still to exponential damping.? i'₀=i_inMoment t (critical moment), had according to Mace law $i_0^{\&prime;}=k_0\sqrt{c_r-i_{\mathrm{in}}t},$ Therefore $t=c_r/i_{\mathrm{in}}-i_{\mathrm{in}}/k_0^2.$

In figure 3, there is t >=t, therefore accumulator can keep all the time with constant current i in time t_inCharge.

Charging capacity c in charging interval t for the accumulator_inIt is the integration of each curve of in figure, can be with formula (4) quantitation table Show:

$c_{\mathrm{in}}=\left\{\begin{array}{cc}\frac{i_0}{\mathrm{\&alpha;}}(1-e^{-\mathrm{\&alpha;t}}),& i_{\mathrm{in}}\&greaterequal;i_0\\ i_{\mathrm{in}}t+\frac{i_{\mathrm{in}}}{{\mathrm{\&alpha;}}^{\&prime;}}(1-e^{-{\mathrm{\&alpha;}}^{\&prime;}(t-t)}),& i_{\mathrm{in}}<i_0,t<t\\ i_{\mathrm{in}}t,& i_{\mathrm{in}}<i_0,t\&greaterequal;t\end{array}\right.---\left(4\right)$

Wherein,i₀=α c_r,c_r=(1-soc (t-1)) c_n, soc (t-1) is to fill The state-of-charge of accumulator, c before electricity_nRated capacity for energy storage.Calculate c_inAfterwards, you can the state-of-charge after being charged is:

Soc (t)=soc (t-1)+c_in/c_r(5)

The control principle of charging process is: (1) is when charging current i_inWhen very big, accumulator can only accept i_inA part, I.e. maximum acceptable electric current i₀, and i in charging process₀Also can be with exponential damping；(2) when charging current i_inDuring very little, electric power storage Pond can be by constant current i_inCharge until terminating；(3) when charging current is between 1) and 3) between when, accumulator is charging In a certain moment before constant current charge, after such a time then exponentially decay current charge.

Taking uninterrupted power supply (ups) system as a example illustrate below, this system uses lotus Bake (hoppecke) lead-acid accumulator, model 24opzv3000, rated capacity is 3000ah, the battery parameter that producer is given such as table 1 Shown.

Table 1 accumulator parameter

Discharge time (h)	1	3	5	10
					Discharge current (a)	1488	744	504	300

The parameter being provided according to producer and correlation test, can record skin Kate electric discharge constant k and n and be respectively 34991 Hes 1.431, Mace law proportionality constant k0 are 95.

At a time, the state-of-charge of accumulator is 90%, due to external electrical network temporary interruption 1 hour, needs electric power storage Pond powers.Calculating battery discharging electric current according to the payload of required power supply is 900a.Using calculating accumulator of the present invention Whether can after continued power in 1h and power supply accumulator dump energy.Controlling stream according to energy-storage system of accumulator Journey, the sustainable discharge time calculating under 900a is 1.86 hours, and therefore labelling accumulator can be powered, accumulator after electric discharge State-of-charge is 60%.

After this battery discharging 1h, external electrical network recovers supply of electric power.Possess the electric power of abundance for guarantee ups power supply, right Accumulator charges, and the charging interval is set as 1h.According to the control flow of energy-storage system of accumulator, calculate the critical of accumulator Charging current is 2328a.After charging 1h, the state-of-charge of accumulator can be calculated as 99.25%.

Apply control method of the present invention can be advantageously applied to management and the charge and discharge control of battery system, realize energy The accurate prediction of amount and Optimum utilization.

It is emphasized that embodiment of the present invention is illustrative rather than determinate, bag therefore of the present invention Include the embodiment being not limited to described in specific embodiment, every by those skilled in the art's technology according to the present invention scheme The other embodiment drawing, also belongs to the scope of protection of the invention.

Claims (6)

1. a kind of energy-storage system of accumulator control method is it is characterised in that comprise the following steps:

Step 1, state-of-charge soc (t) of reading current time accumulator；

Step 2, according to the load prediction results in system future a period of time δ t, accumulator and outside exchange in estimation δ t Power p_ex；

Step 3, according to battery system working voltage, calculate in δ t with outside exchanging electric current i_ex=p_ex/u；

If step 4 exchanging electric current i_ex＞ 0, represents battery discharging, execution step 5, otherwise execution step 6；

Step 5, battery discharging rate-determining steps, its concrete processing procedure is: in calculating δ t, accumulator maximum can discharge current i_outmaxIf, i_outmax≥i_ex, labelling accumulator can be powered, and calculates state-of-charge soc (t) the conduct ginseng of accumulator after electric discharge Examine；If i_outmax＜ i_ex, prompt system short of electricity warning information；

Step 6, Battery charge controller step, its concrete processing procedure is: the acceptable electric current of calculating accumulator and accumulator Charging capacity c in charging interval t_in, charging current i_in＜ i₀, accumulator is with i_inConstant current charge；Otherwise, estimate electric power storage Critical charging current i of maximum in δ t for the pond_inmax, and control system is with i_inmaxCharge for accumulator, simultaneously in prompt system Electric energy is superfluous, needs cut-out power supply, wherein, i₀For the maximum initial current value allowing when starting to charge up.

2. a kind of energy-storage system of accumulator control method according to claim 1 it is characterised in that: in described calculating δ t Accumulator maximum can discharge current i_outmaxUsing equation below:

$t=\frac{k\&times;soc(t-1)}{i_{outmax}^n}$

Wherein, soc (t-1) be electric discharge initial time accumulator state-of-charge, t be the sustainable electric discharge of accumulator time, k and N is the constant depending on different batteries self-discharge characteristic.

3. a kind of energy-storage system of accumulator control method according to claim 1 it is characterised in that: described calculate electric discharge after The state-of-charge of accumulator adopts equation below:

Wherein, i_outFor the discharge current of accumulator, t is in electric current i_outUnder the actual discharge time, c_nFor the specified appearance of accumulator Amount, soc (t) is the state-of-charge of accumulator after the completion of electric discharge；Soc (t-1) is the state-of-charge of accumulator before electric discharge；T is to store The time of battery lasts electric discharge.

4. a kind of energy-storage system of accumulator control method according to claim 1 it is characterised in that: described calculating accumulator Acceptable electric current adopt equation below:

I=i₀e^-αt

Wherein, i₀For the maximum initial current value allowing when starting to charge up, α is that the charging of accumulator is subject to ratio for characterizing electric power storage The charging in pond is subject to characteristic.

5. a kind of energy-storage system of accumulator control method according to claim 1 it is characterised in that: described calculating accumulator Charging capacity c in charging interval t_inUsing equation below:

$c_{in}=\left\{\begin{array}{cc}\frac{i_0}{\mathrm{\&alpha;}}(1-e^{-\mathrm{\&alpha;}t}),& i_{in}\&greaterequal;i_0\\ i_{in}t+\frac{i_{in}}{{\mathrm{\&alpha;}}^{\&prime;}}(1-e^{-{\mathrm{\&alpha;}}^{\&prime;}(t-t)}),& i_{in}<i_0,t<t\\ i_{in}t,& i_{in}<i_0,t\&greaterequal;t\end{array}\right.$

Wherein,i₀=α c_r,c_r=(1-soc (t-1)) c_n, before soc (t-1) is charging The state-of-charge of accumulator, c_nFor the rated capacity of energy storage, k₀For Mace law proportionality constant, α for accumulator charging be subject to than.

6. a kind of energy-storage system of accumulator control method according to claim 1 it is characterised in that: described need cut portion Independent power source power is (i_ex-i_inmax)u.