CN101275991A - Method and device for estimating battery residual capacity, and battery power supply system - Google Patents

Abstract

In the method for estimating battery residual capacity of the present invention, the voltage measurement values are obtained (step S 2 ). And once it is finished, using the initial values of the coefficients set at the step S 3 as starting, the optimization is progressed with renewing each value of the coefficients on the following iterating calculations (step S 4 ). Once the optimum value of each coefficient in the approximation is determined at the step S 4 , the stable open circuit voltage is calculated by the optimized reciprocal function using thereof at the step S 5 . And then based thereon, the battery residual capacity is calculated by the predetermined conversion method (step S 6 ).

Description

Estimating battery residual capacity method and device, battery power supply system

Technical field

The present invention relates to a kind ofly infer estimating battery residual capacity method, estimating battery residual capacity device and battery power supply system to the residual capacity of the battery of load supply capability based on stablizing open-circuit voltage.

Background technology

In recent years, because of the portability of electronic equipment, the hybrid power of automobile (hybrid) change, nothing idle running (idle stop) change etc., the charge rate of the battery supply that correct deduction is carried or the requirement of residual capacity are strong day by day.As the method for inferring this charge rate or residual capacity, there is the method for inferring based on the stable open-circuit voltage (OCV) of battery, this method is the easiest, as realizing that the correct method of inferring is effective.

But, in fact in the environment that uses power-supply system, because therefore the charging and discharging currents that frequently flows in battery, often produces polarization in the inside of battery.So even during discharging and recharging, the polarizing voltage that also can superpose on the cell voltage almost can't realize the state that cell voltage is consistent with OCV voltage.

Consider the influence that this polarization produces, for example open that flat 7-98367 communique, spy are opened the 2002-234408 communique, the spy opens and discloses the method for stablizing open-circuit voltage of inferring in the 2005-43339 communique the spy.In these communiques, the polarization that causes that discharges and recharges of battery relaxes in time, and cell voltage is converged on the function that the voltage action of stablizing open-circuit voltage shows as the time.Proposed to utilize the result who in than the short period, measures cell voltage to determine the coefficient of the function of time, thereby prediction is through the technology of the stable open-circuit voltage after long-time.

As an example, open in the flat 7-98367 communique change in voltage V (t) of the battery when discharging and recharging once the reciprocal function performance relevant the spy with time t.

V (t)=C-(at+b) ^-1(formula 1) utilizes above-mentioned function, defined property function F (t)=t * dV (t)/dt, based on this obtain the t=tmax that makes F (t) maximum (=a/b), and then, as coefficient C=2V (tmax)-V (t0), calculate stable open-circuit voltage.

In addition, open in the 2002-234408 communique the spy, proposed following method: the change in voltage V of the battery in the time of will discharging and recharging (t) shows as formula (2), determine the optimum value of factor alpha and OCV by the least square computing, and will be as the optimum value of the OCV of coefficient as stablizing open-circuit voltage.

V (t)=α t ^-0.5+ OCV (=α t ^D+ OCV) (formula 2)

And then open the spy and to have proposed following method in the 2005-43339 communique: the change in voltage V of the battery in the time of will discharging and recharging (t) is with the exponential function more than four times

V(t)＝A1·exp(B1/t)+A2·exp(B2·t)

+ ... + V0 (formula 3)

Performance is determined by least square computing optimization coefficient Ai, Bi, V0.

But there are the following problems in above-mentioned prior art.Open in the flat 7-98367 communique the spy, the change in voltage of the battery when discharging and recharging not is for only representing such simple action by the inverse function of above-mentioned (formula 1) with (formula 1) performance but the polarization of cells known voltage relaxes action.Therefore, existence can not be stablized the problem that open-circuit voltage is inferred battery residual capacity with enough accuracy predictions.

In addition, open in the flat 7-98367 communique, defined characteristic function, and calculated stable open-circuit voltage based on this spy.But in this method, infer that with utilizing the optimum coefficient of calculating the method for change in voltage compares, be difficult to stablize open-circuit voltage with high-precision forecast by least square method.

Open in the 2002-234408 communique the spy, the change in voltage of the battery when discharging and recharging is with (formula 2) performance, exponential D is approximately-0.5 o'clock factor alpha and the value of OCV is defined as optimum value.But the function of Que Dinging also exists the polarization with actual cell voltage to relax the problem that action deviates from fully like this.

With respect to this, open in the 2005-43339 communique the spy, the change in voltage V (t) of the battery when discharging and recharging shows with (formula 3) of having utilized the exponential function more than four times, therefore can very high degree of precision ground prediction stablizing open-circuit voltage.But, in (formula 3), used complexity and the high exponential function of calculated load morely, therefore there is the high problem of calculated load.And then, exponential function in time the value of variable variation and to be worth change very big, the situation of the astronomical numerical value of expression can appear in its calculating process sometimes.For example, when utilizing the controller that carries in the automobile the limited arithmetic element of capacity, exist numerical value can exceed element process range, be difficult to stablize the problem of computing.

Summary of the invention

The present invention realizes that for addressing these problems purpose is to provide a kind of and stablizes open-circuit voltage and can infer the light estimating battery residual capacity method of residual capacity, calculated load of battery based on stablizing open-circuit voltage very high degree of precision ground by the high precision deduction.

First technical scheme of estimating battery residual capacity method of the present invention is, a kind ofly infers the estimating battery residual capacity method of the residual capacity of battery based on stablizing open-circuit voltage, and this estimating battery residual capacity method comprises the steps:

Establish t be from elapsed time, n that the magnitude of voltage that discharges and recharges the battery after stopping to be obtained beginning be integer, F (t) more than 2 be the arbitrary function of described time t, when C is constant, utilize open-circuit voltage that denominator is similar to described battery for the function (hereinafter referred to as n reciprocal function) of the polynomial of degree n of time t over time

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+F\left(t\right)+C$

Obtain beginning at the appointed time from described magnitude of voltage, obtain the above magnitude of voltage of number of coefficient described battery, described n reciprocal function, and based on obtained described magnitude of voltage, by least square method or Kalman filtering computing or neural network, determine the value of the coefficient of described n reciprocal function

Utilize the value of described definite coefficient, calculate stable open-circuit voltage according to described n time reciprocal function, and infer described residual capacity based on described stable open-circuit voltage of calculating.

Another technical scheme of estimating battery residual capacity method of the present invention is characterized in that, establishing described n reciprocal function is following formula:

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+C.$

Another technical scheme of estimating battery residual capacity method of the present invention, it is characterized in that, when from discharging and recharging time till stopping to begin obtaining beginning in first reference time when following to the magnitude of voltage of described battery, change in voltage when being similar to described open circuit with described n reciprocal function, time till obtaining beginning to described magnitude of voltage surpasses described first reference time and in second reference time when following, change in voltage when being similar to described open circuit with (n-1) inferior described reciprocal function, after, at every turn when the time till described magnitude of voltage is obtained beginning surpasses the reference time of regulation, be similar to after all the number of times of described reciprocal function being reduced 1 successively, reach till 1 until described number of times.

First technical scheme of estimating battery residual capacity device of the present invention is, a kind ofly infer the estimating battery residual capacity device of the residual capacity of battery based on stablizing open-circuit voltage, this estimating battery residual capacity device comprises: voltage sensor, and its voltage to described battery is measured; And control part, it carries out control to being used to infer the computing of described residual capacity; Described control part establish t be from elapsed time, n that the magnitude of voltage that discharges and recharges the battery after stopping to be obtained beginning be integer, F (t) more than 2 be the arbitrary function of described time t, when C is constant, utilize open-circuit voltage that denominator is similar to described battery for the function (hereinafter referred to as n reciprocal function) of the polynomial of degree n of time t over time

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+F\left(t\right)+C$

Obtain beginning at the appointed time from described magnitude of voltage, obtain the above magnitude of voltage of number of coefficient described battery, described n reciprocal function, and based on obtained described magnitude of voltage, by least square method or Kalman filtering computing or neural network, determine the value of the coefficient of described n reciprocal function, utilize the value of described definite coefficient, calculate stable open-circuit voltage according to described n time reciprocal function, and infer described residual capacity based on described stable open-circuit voltage of calculating.

Another technical scheme of estimating battery residual capacity device of the present invention is characterized in that, described control part uses following formula as described n reciprocal function.

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+C$

Another technical scheme of estimating battery residual capacity device of the present invention, it is characterized in that, described control part is when from discharging and recharging time till stopping to begin obtaining beginning to the magnitude of voltage of described battery in first reference time when following, change in voltage when being similar to described open circuit with described n reciprocal function, time till obtaining beginning to described magnitude of voltage surpasses described first reference time and in second reference time when following, change in voltage when being similar to described open circuit with (n-1) inferior described reciprocal function, after, at every turn when the time till described magnitude of voltage is obtained beginning surpasses the reference time of regulation, be similar to after all the number of times of described reciprocal function being reduced 1 successively, reach till 1 until described number of times.

First technical scheme of battery power supply system of the present invention is characterized in that, comprising: each described estimating battery residual capacity device in described battery and the technique scheme.

Description of drawings

Fig. 1 is the process flow diagram of flow process of processing of the estimating battery residual capacity method of expression first embodiment of the present invention;

Fig. 2 is the block diagram that the summary of expression estimating battery residual capacity device of first embodiment of the present invention and battery power supply system constitutes;

Fig. 3 is the figure that the approximate expression to the measured value of open-circuit voltage and reciprocal function compares;

Fig. 4 is the process flow diagram of flow process of processing of the estimating battery residual capacity method of expression second embodiment of the present invention.

Embodiment

With reference to accompanying drawing, the formation of the estimating battery residual capacity method in the preferred implementation of the present invention, estimating battery residual capacity device and battery power supply system is elaborated.In addition, owing to, therefore mark prosign to having each formation portion simplicity of illustration and explanation of same function.

Fig. 2 is the block diagram that the summary of expression estimating battery residual capacity device of embodiments of the present invention and battery power supply system constitutes.The battery power supply system 100 of present embodiment constitutes and comprises: the estimating battery residual capacity device 200 of battery 110, charging circuit 120, present embodiment, load 10 is connected with battery 110.

In addition, estimating battery residual capacity device 200 comprises: control part 210, storage part 220, voltage sensor 230.The embodiment that control part 210 utilizes estimating battery residual capacity method of the present invention is carried out control to being used to infer the computing of residual capacity, and then, also can constitute the action of control battery power supply system 100 integral body.In Fig. 2, the formation that adopts control part 210 control charging circuits 120 to carry out the charging of battery 110.

Voltage sensor 230 is measured the voltage between terminals of battery 110, sends detected voltage determination value to control part 210.Storage part 220 is preserved: various parameters of using in the deduction computing of the residual capacity of being handled by control part 210 etc., by voltage sensor 230 detected voltage determination values etc.

When the battery power supply system 100 with present embodiment is applied to automotive power supply system, utilize for motor vehicle lead accumulator as battery 110, become the system of load 10 supply powers of motor of on vehicle, carrying etc.Comprise that in for motor vehicle lead accumulator alternator (alternator) is as charging circuit 120.

Then, in the battery power supply system 100 of present embodiment, the estimating battery residual capacity method of the present embodiment of the residual capacity of inferring battery 110 is described.As mentioned above, there is close correlationship in the stable open-circuit voltage of the residual capacity of battery 110 and battery 110, therefore, can preestablish according to stablizing the unique relational expression of calculating residual capacity of open-circuit voltage.By utilizing such relational expression, infer the stable open-circuit voltage of battery 110 accurately, thereby can infer the residual capacity of battery 110 accurately.

On the other hand, under the practice situation of battery 110, because from the frequent repetition of discharging and recharging of battery 110, therefore, the inside that is in battery 110 during the major part has produced the situation of polarization, also is superimposed with polarizing voltage on the voltage of battery 110.The influence of this polarization can slowly reduce after discharging and recharging of battery 110 stops, and needs tens hours to several days such time of extremely growing but become in this influence before enough little.Open-circuit voltage when therefore, stablizing after the mensuration polarization canceling is difficulty very.Can't expect it is applied in the practicality.

Therefore, the estimating battery residual capacity method of present embodiment, utilize the approximate function that stops the change in time of back open-circuit voltage that discharges and recharges of energy high precision, and the voltage determination value that this function utilization is detected by voltage sensor 230 determined the coefficient of described function, thereby can high precision infer battery 110 open-circuit voltage after stable.

Below describe the estimating battery residual capacity method of present embodiment in detail.In the present embodiment, as the approximate function that stops the change in time of back open-circuit voltage that discharges and recharges of high precision, utilize denominator for the polynomial of degree n of time t as shown in the formula function (hereinafter referred to as n reciprocal function).

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+F\left(t\right)+C$ (formula 4)

Here, the time t of establishing begins elapsed time from the magnitude of voltage of obtaining battery 110, and establishing V (t) is the open-circuit voltage of battery 110, establishes n and be the integer more than 2, and establishing F (t) is the arbitrary function of time t, and establishing C is constant.

In the present embodiment, establish open-circuit voltage V (t) by as the reciprocal function of (formula 4) represent that the frequency n by making reciprocal function is at least more than 2, thereby open-circuit voltage that can the approximate battery 110 of high precision over time.In (formula 4), first reciprocal function is similar to discharge and recharge and stops after-polarization voltage over time on the right of utilizing, and second F (t) can set arbitrarily as required.

Below, as another embodiment, the estimating battery residual capacity method during to the reciprocal function of the following formula that do not utilize second F (t) describes.

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+C$ (formula 5)

Adorn in the estimating battery residual capacity method of 200 performed present embodiments at estimating battery residual capacity, make stop from discharging and recharging of battery 110 after, utilize voltage sensor 230 to measure the open-circuit voltage of battery 110, and determine the coefficient A of (formula 5) based on this voltage determination value _i, B _i, C.

Coefficient A as (formula 5) _i, B _i, C definite method, can utilize least square method, Kalman filtering (Kalman filter) computing or neural network (neural networe).For example, when utilizing least square method, in order to ask for coefficient A _i, B _i, C optimum value, be defined as follows the sum of square of deviations function of formula, ask for coefficient A _i, B _i, C is till this function minimum.

$M=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\{\mathrm{Vm}\left(t_k\right)-V\left(t_k\right)\}}^2$ (formula 6)

Here, the voltage determination value that Vm (k) expression is obtained by voltage sensor 230, t _kExpression discharges and recharges the time of the voltage determination point after stopping.Voltage determination point all is the k point.

As asking for the coefficient A that makes the sum of square of deviations M minimum shown in above-mentioned (formula 6) _i, B _i, C method, use Gauss-Newton method or Levenberg-Marquardt method etc. according to begin to reduce the mode of M successively from predetermined initial value with coefficient A _i, B _i, C is updated to the such recursive operation method of optimum value and gets final product.

At the secondary reciprocal function is example, and expression is asked for the example that the optimum coefficient of this function is separated by the Gauss-Newton method below.With the secondary reciprocal function

$V\left(t\right)=\frac{1+A_1\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="t\; B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">t</figure-callout>}}{B_{}}+C$ (formula 7)

Be rewritten as following formula.

$V\left(t\right)=\frac{1}{\mathrm{\&alpha;}1\&CenterDot;t+\mathrm{\&alpha;}3}+\frac{1}{\mathrm{\&alpha;}2\&CenterDot;t+\mathrm{\&alpha;}4}+\mathrm{\&alpha;}5$ (formula 8)

And then the discrete value as at interval open-circuit voltage V (t) being sampled and obtains with Δ T is rewritten as following formula.

$V\left(n\right)=\frac{1}{\mathrm{\&alpha;}1\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}3}+\frac{1}{\mathrm{\&alpha;}2\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}4}+\mathrm{\&alpha;}5$ (formula 9)

If with the actual cell voltage measured value of measuring in Δ T interval is that (n=1～Ns), establish its difference with the value of calculating according to above-mentioned mathematical expression is following formula to V m (n).

R (n)=V (n)-Vm (n) (formula 10)

Then, when using least square method, the partial differential item that each factor alpha 1～α 5 of (formula 6) is correlated with is asked for by each sampling instant by following (formula 11).

$\mathrm{dDF\&alpha;}1\left(n\right)=\frac{-n\&CenterDot;\mathrm{\&Delta;T}}{{(\mathrm{\&alpha;}1\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}3)}^2}$

$\mathrm{dDF\&alpha;}2\left(n\right)=\frac{-n\&CenterDot;\mathrm{\&Delta;T}}{{(\mathrm{\&alpha;}2\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}4)}^2}$

$\mathrm{dDF\&alpha;}3\left(n\right)=\frac{-1}{{(\mathrm{\&alpha;}1\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}3)}^2}$ (formula 11)

$\mathrm{dDF\&alpha;}4\left(n\right)=\frac{-1}{{(\mathrm{\&alpha;}2\&CenterDot;\mathrm{\&Delta;T}\&CenterDot;n+\mathrm{\&alpha;}4)}^2}$

dDFα5(n)＝1

Then, the partial differential item of be correlated with based on resulting each factor alpha 1～α 5 by each sampling instant by following (formula 12), is that (i j) calculates Hai Sai (Hesse) matrix B to 5 * 5 square symmetric matrixes of the simultaneous equations of suitable least square method.

$B\left(\mathrm{1,1}\right)=\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}{\left\{\mathrm{dDF\&alpha;}1\left(n\right)\right\}}^2$

$B\left(\mathrm{1,2}\right)=\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}1\left(n\right)\&times;\mathrm{dDF\&alpha;}2\left(n\right)\}$

$B\left(\mathrm{1,3}\right)=\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}1\left(n\right)\&times;\mathrm{dDF\&alpha;}3\left(n\right)\}$ (formula 12)

.

.

.

$B\left(\mathrm{5,5}\right)=\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}{\left\{\mathrm{dDF\&alpha;}5\left(n\right)\right\}}^2$

And then the partial differential item based on each the factor alpha 1～α 5 by each sampling instant that obtains equally is correlated with calculates the dR1～dR5 shown in following (formula 13).

$\mathrm{dR}1=-\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}1\left(n\right)\&times;R\left(n\right)\}$

$\mathrm{dR}2=-\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}2\left(n\right)\&times;R\left(n\right)\}$

$\mathrm{dR}3=-\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}3\left(n\right)\&times;R\left(n\right)\}$ (formula 13)

$\mathrm{dR}4=-\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}4\left(n\right)\&times;R\left(n\right)\}$

$\mathrm{dR}5=-\underset{n=1}{\overset{\mathrm{Ns}}{\mathrm{\&Sigma;}}}\{\mathrm{dDF\&alpha;}5\left(n\right)\&times;R\left(n\right)\}$

Like this, the variation of the correction in the recursive operation of factor alpha 1～α 5 dd1～dd5 calculates by following (formula 14).

$\left(\begin{array}{c}\mathrm{dd}1\\ \mathrm{dd}2\\ \mathrm{dd}3\\ \mathrm{dd}4\\ \mathrm{dd}5\end{array}\right)={\left(\begin{array}{ccccc}B\left(\mathrm{1,1}\right)& B\left(\mathrm{1,2}\right)& B\left(\mathrm{1,3}\right)& B(1,4)& B(1,5)\\ B\left(\mathrm{2,1}\right)& B(2,2)& B(2,3)& B(2,4)& B(2,5)\\ B(3,1)& B(3,2)& B(3,3)& B\left(\mathrm{3,4}\right)& B(3,5)\\ B(4,1)& B(4,2)& B\left(\mathrm{4,3}\right)& B(4,4)& B(4,5)\\ B(5,1)& B(5,2)& B(5,3)& B(5,4)& B(5,5)\end{array}\right)}^{-1}\&times;\left(\begin{array}{c}\mathrm{dR}1\\ \mathrm{dR}2\\ \mathrm{dR}3\\ \mathrm{dR}4\\ \mathrm{dR}5\end{array}\right)$ (formula 14)

Till above-mentioned dd1～dd5 is very little,, (formula 9)～(formula 15) carried out computing repeatedly according to following (formula 15) update coefficients α 1～α 5.

$\left(\begin{array}{c}\mathrm{\&alpha;}1\\ \mathrm{\&alpha;}2\\ \mathrm{\&alpha;}3\\ \mathrm{\&alpha;}4\\ \mathrm{\&alpha;}5\end{array}\right)=.\left(\begin{array}{c}\mathrm{\&alpha;}1+\mathrm{dd}1\\ \mathrm{\&alpha;}2+\mathrm{dd}2\\ \mathrm{\&alpha;}3+\mathrm{dd}3\\ \mathrm{\&alpha;}4+\mathrm{dd}4\\ \mathrm{\&alpha;}5+\mathrm{dd}5\end{array}\right)$ (formula 15)

According to aforesaid least square method, the open-circuit voltage V (t) that is represented by the reciprocal function of (formula 5) is approximately consistent accurately with voltage determination value Vm (k), and can infer the variation of long open-circuit voltage accurately.In the estimating battery residual capacity method of present embodiment,, therefore, the load of the optimized calculation process of coefficient of the approximate expression of open-circuit voltage is alleviated significantly owing to do not use exponential function fully in the aforementioned calculation process.

Expression is similar to an example of open-circuit voltage with the reciprocal function shown in (formula 5) in Fig. 3.Approximate expression shown in this figure is utilized following secondary reciprocal function.

$V\left(t\right)=\frac{1+A_1\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="t\; B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">t</figure-callout>}}{B_{}}+C$ (formula 16)

In Fig. 3, heavy line 310 expression measured values, the value of (formula 16) of dotted line 320 expression open-circuit voltages.As shown in the drawing, very consistent by the formula 320 of the approximate open-circuit voltage of above-mentioned secondary reciprocal function with measured value 310.In addition, the R that has represented the consistent degree between open-circuit voltage formula 320 and the measured value 310 ²Be 0.99525 and near 1 value.

As the coefficient A that determines (formula 5) _i, B _i, C additive method, have Kalman filtering computing and neural network, but in the Kalman filtering computing, with coefficient A _i, B _i, C or the mathematical expression that comprises this coefficient be set at state vector X _k, determine thus: Jacobi (Jacob) matrix that the one-step prediction of state vector on time series determined, calculate V (t as observed reading according to state vector _k) observation equation.From predetermined like this coefficient A _i, B _i, the initial value of C and the initial measured value V of k=1 ₁(t ₁) beginning, increase and measured value V according to count k along with the observation of voltage measured value _m(t _k) and calculated value V (t _k) error become minimum mode, carry out repeatedly according to Kalman filtering algorithm that kalman gain calculates, update mode vector X successively _k, state vector one-step prediction, thereby, along with the carrying out of observing makes coefficient A gradually _i, B _i, the C optimization.

In addition, using under the situation of neural network, selecting as the suitable network of multistage perceptron (perceptron), in advance the measured value of adequate preparation voltage and the coefficient A that is optimized by this measured value _i, B _i, C various examples, these are educated network by backpropagation proper methods such as (backpropagation) as teacher signal, thereby the measured value by giving voltage to network can obtain coefficient A as input _i, B _i, C optimum value as output.

Utilize process flow diagram shown in Figure 1, further describe the deduction method of the performed battery residual capacity of the estimating battery residual capacity device 200 of the present embodiment of having utilized least square method.At first, in step S1,, then in step S2, utilize the voltage (open-circuit voltage) of 230 pairs of batteries 110 of voltage sensor to measure if judgement stops from discharging and recharging of battery 110.In this is measured, obtain the above voltage determination value of number of the coefficient that reciprocal function comprised of (formula 4) or (formula 5) that open-circuit voltage is similar to.

The voltage determination value obtain end after, in step S3, set initial value by the coefficient of the optimized reciprocal function of least square method.In step S4, be starting point with the initial value of the coefficient set among the step S3, carry out optimization while upgrade the value of each coefficient in the repeated calculation afterwards.After in step S4, having determined the optimum value of each coefficient of approximate expression, in step S5, calculate stable open-circuit voltage according to the reciprocal function that has utilized this optimum value to be optimized.

And then, in step S6,, calculate battery residual capacity with the transform method of regulation based on the stable open-circuit voltage of in step S5, calculating.Can utilize transform that is formed and stored in advance the storage part 220 etc. from stablizing open-circuit voltage to the conversion of battery residual capacity.

Another embodiment to the deduction method of battery residual capacity of the present invention describes below.In the present embodiment,, also used the reciprocal function of (formula 4) or (formula 5) as the function that the open-circuit voltage to battery 110 is similar to, below, as an example, be that 4 example describes to the frequency n in the reciprocal function of (formula 5).At this moment, the open-circuit voltage V (t) of battery 110 is shown below.

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+A_3\&CenterDot;t^3}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+B_3\&CenterDot;t^3+B_4\&CenterDot;t^4}+C$ (formula 17)

Discharge and recharge the battery 110 after stopping open-circuit voltage variation for example as shown in Figure 3, show rapid variation after just stopping discharging and recharging, relax gradually along with the process of time.Utilize (formula 17), can be similar to the variation of open-circuit voltage as shown in Figure 3 accurately.Especially, for the approximate rapid variation that discharges and recharges after just stopping of high precision, the preferred reciprocal function that utilizes as the high order of (formula 17).

But the variation meeting of the open-circuit voltage mitigation that becomes along with the process of time for the variation to the open-circuit voltage that discharges and recharges the mitigation of having passed through the stipulated time after stopping is similar to, need not to utilize the reciprocal function of high order.Therefore, in the present embodiment, according to from discharging and recharging the time span till stopping to begin beginning, reduce the frequency n of the reciprocal function of use in open-circuit voltage approximate to the mensuration of the open-circuit voltage of battery 110.

At first, be located at make discharging and recharging of battery 110 stop after to the time that begins till the voltage determination of batteries 110 by voltage sensor 230 in order to obtain voltage determination value Vm (k) be tx, then do not reach under the situation of first reference time, use (formula 17) approximate expression as open-circuit voltage at time tx.In addition, surpassed at time tx under the situation of first reference time, used number of times with the reciprocal function of (formula 17) to subtract following formula after one as the approximate expression of open-circuit voltage.

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+B_3\&CenterDot;t^3}+C$ (formula 18)

And, surpassed at time tx under the situation of second reference time, use number of times with the reciprocal function of (formula 18) to subtract following formula after one as the approximate expression of open-circuit voltage.

$V\left(t\right)=\frac{1+A_1\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="t\; B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">t</figure-callout>}}{B_{}}+C$ (formula 19)

And then, surpassed at time tx under the situation of the 3rd reference time, use number of times with the reciprocal function of (formula 19) to subtract following formula after one as the approximate expression of open-circuit voltage.

$V\left(t\right)=\frac{1}{{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="A20081008735600191.png"\; state="\{\{state\}\}">B</figure-callout>}}_0+B_1\&CenterDot;t}+C$ (formula 20)

Because the frequency n of (formula 20) has reached 1, therefore do not use the reciprocal function of further minimizing frequency n.

As mentioned above, reduce the frequency n of the reciprocal function that open-circuit voltage is similar to according to the time till stopping from discharging and recharging of battery 110 beginning beginning to voltage determination, thereby, required computing time of optimal approximation of reciprocal function can be shortened.

Utilize process flow diagram shown in Figure 4, further describe the estimating battery residual capacity method of above-mentioned present embodiment.At first, in step S11,, then in step S12, measure from discharging and recharging the elapsed time that stops to begin if judgement stops from discharging and recharging of battery 110.

In step S13, judge from discharging and recharging the elapsed time that stops to begin whether reached the stipulated time, be judged to be reached the stipulated time after, in step S14, utilize voltage sensor 230 to measure the voltage (open-circuit voltage) of batteries 110.In this is measured, obtain the above voltage determination value of number of the coefficient that reciprocal function comprised of (formula 4) or (formula 5) that open-circuit voltage is similar to.

The voltage determination value obtain end after, in step S15, the length in elapsed time till beginning according to the voltage determination to battery 110 is determined the number of times of the reciprocal function of (formula 4) or (formula 5) that open-circuit voltage is similar to.In step S16, set initial value by the coefficient of the optimized reciprocal function of least square method.In step S17, be starting point with the initial value of the coefficient set among the step S16, carry out optimization while upgrade the value of each coefficient in the repeated calculation afterwards.After in step S17, having determined the optimum value of each coefficient of approximate expression, in step S18, calculate stable open-circuit voltage according to the reciprocal function that has utilized this optimum value to be optimized.

And then, in step S19,, calculate battery residual capacity with the transform method of regulation based on the stable open-circuit voltage of in step S17, calculating.Can utilize transform that is formed and stored in advance the storage part 220 etc. from stablizing open-circuit voltage to the conversion of battery residual capacity.

In the estimating battery residual capacity method of present embodiment,, therefore, the load of the optimized calculation process of coefficient of the approximate expression of open-circuit voltage is alleviated significantly because the aforementioned calculation process do not use exponential function fully yet.

As mentioned above, in estimating battery residual capacity method of the present invention, be similar to the time response of the reciprocal function more than the secondary the open-circuit voltage of battery, therefore, the convergency value of open-circuit voltage can be obtained at short notice, the charge rate of battery can be correctly and stably inferred with few calculated load.In addition, in the method for having utilized exponential function, the variation of the value of variable in time and to be worth change very big is difficult to stablize computing, but in having utilized the estimating battery residual capacity method of the present invention of reciprocal function, can stably carries out computing.

Present embodiment only is similar to open-circuit voltage with reciprocal function, but other suitable functions also capable of being combined exponential function etc. for example.The number of times of reciprocal function of this moment and the number of times of exponential function are considered calculated load and precision prescribed and are suitably selected.In this case, can adopt reciprocal function once, the combination of the exponential function below three times fully.

As mentioned above, according to the present invention, be similar to the time response of the reciprocal function more than the secondary the open-circuit voltage of battery, therefore, can provide the convergency value that to obtain open-circuit voltage at short notice also can correctly and stably infer the charge rate deduction method of the charge rate of battery with few calculated load.

In addition, an example of estimating battery residual capacity method involved in the present invention, estimating battery residual capacity device and battery power supply system is represented in the record in the present embodiment, but is not limited thereto.About the part formation and the detailed actions etc. in detail such as estimating battery residual capacity method of present embodiment, in the scope that does not break away from aim of the present invention, can suitably change.

Claims (7)

1, a kind of estimating battery residual capacity method is inferred the residual capacity of battery based on stablizing open-circuit voltage, and this estimating battery residual capacity method comprises the steps:

Establish t be from the magnitude of voltage that discharges and recharges the battery after stopping to obtain the elapsed time, the n that begin be integer, F (t) more than 2 be the arbitrary function of described time t, when C is constant, utilize denominator for the function of the polynomial of degree n of time t, be n reciprocal function:

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{B_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;B_n\&CenterDot;t^n}+F\left(t\right)+C$

The open-circuit voltage that is similar to described battery over time, obtain from described magnitude of voltage and to begin at the appointed time, obtain the above magnitude of voltage of number of coefficient described battery, described n reciprocal function, and based on obtained described magnitude of voltage, by least square method or Kalman filtering computing or neural network, determine the value of the coefficient of described n reciprocal function

Utilize the value of described definite coefficient, calculate stable open-circuit voltage according to described n time reciprocal function, and infer described residual capacity based on described stable open-circuit voltage of calculating.

2, estimating battery residual capacity method according to claim 1 is characterized in that,

If described n reciprocal function is following formula:

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;A_{n-1}\&CenterDot;t^{n-1}}{B_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+C.$

3, estimating battery residual capacity method according to claim 1 and 2 is characterized in that,

When from discharging and recharging time till the magnitude of voltage that stops to begin playing described battery is obtained beginning in first reference time when following, change in voltage during with the approximate described open circuit of described n reciprocal function,

Time till obtaining beginning to described magnitude of voltage surpasses described first reference time and in second reference time when following, change in voltage during with the approximate described open circuit of (n-1) inferior described reciprocal function,

After, at every turn when the time to described magnitude of voltage is obtained beginning till surpasses the reference time of stipulating, be similar to after all the number of times of described reciprocal function being reduced 1 successively, reach till 1 until described number of times.

4, a kind of estimating battery residual capacity device is inferred the residual capacity of battery based on stablizing open-circuit voltage,

This estimating battery residual capacity device comprises:

Voltage sensor, its voltage to described battery is measured; With

Control part, it carries out control to being used to infer the computing of described residual capacity;

Described control part establish t be from the magnitude of voltage that discharges and recharges the battery after stopping to obtain the elapsed time, the n that begin be integer, F (t) more than 2 be the arbitrary function of described time t, when C is constant, utilize denominator for the function of the polynomial of degree n of time t, be n reciprocal function:

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{B_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+F\left(t\right)+C$

The open-circuit voltage that is similar to described battery over time, obtain from described magnitude of voltage and to begin at the appointed time, obtain the above magnitude of voltage of number of coefficient described battery, described n reciprocal function, and based on obtained described magnitude of voltage, by least square method or Kalman filtering computing or neural network, determine the value of the coefficient of described n reciprocal function, utilize the value of described definite coefficient, calculate stable open-circuit voltage according to described n time reciprocal function, and infer described residual capacity based on described stable open-circuit voltage of calculating.

5, estimating battery residual capacity device according to claim 4 is characterized in that,

Described control part uses following formula as described n reciprocal function:

$V\left(t\right)=\frac{1+A_1\&CenterDot;t+A_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+A_{n-1}\&CenterDot;t^{n-1}}{B_0+B_1\&CenterDot;t+B_2\&CenterDot;t^2+\&CenterDot;\&CenterDot;\&CenterDot;+B_n\&CenterDot;t^n}+C.$

6, according to claim 4 or 5 described estimating battery residual capacity devices, it is characterized in that,

Described control part is when from discharging and recharging time till the magnitude of voltage that stops to begin playing described battery is obtained beginning in first reference time when following, change in voltage when being similar to described open circuit with described n reciprocal function, time till obtaining beginning to described magnitude of voltage surpasses described first reference time and in second reference time when following, change in voltage when being similar to described open circuit with (n-1) inferior described reciprocal function, after, at every turn when the time till described magnitude of voltage is obtained beginning surpasses the reference time of regulation, be similar to after all the number of times of described reciprocal function being reduced 1 successively, reach till 1 until described number of times.

7, a kind of battery power supply system comprises: each described estimating battery residual capacity device in described battery and the claim 4～6.

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