CN103593577A - Photovoltaic power generation system output power modeling and estimation method - Google Patents

Abstract

The invention discloses a photovoltaic power generation system output power modeling and estimation method. The photovoltaic power generation system output power modeling method comprises the steps of establishing a photovoltaic module current-voltage characteristic model according to a solar cell current-voltage characteristic model, simplifying the photovoltaic module current-voltage characteristic model, and establishing a photovoltaic power generation system output power model according to the simplified photovoltaic module current-voltage characteristic model. The photovoltaic power generation system output power estimation method comprises the steps of establishing the photovoltaic power generation system output power model, acquiring characteristic parameters under photovoltaic module standard test conditions, obtaining parameters in the output power model, obtaining original meteorological parameters, correcting the meteorological parameters into photovoltaic module actual operating temperature and absorbed effective irradiation, and inputting the corrected meteorological parameters to the model to obtain photovoltaic module output power. By means of the photovoltaic power generation system output power modeling and estimation method, accurate estimation of output power of a photovoltaic power generation system can be realized, power station designers can be helped to carry out benefit analysis, and prediction of the output power of the photovoltaic power generation system is realized.

Description

The modeling of a kind of photovoltaic generating system output power and evaluation method

Technical field

The present invention relates to field of photovoltaic power generation, particularly relate to the modeling of a kind of photovoltaic generating system output power and evaluation method.

Background technology

Photovoltaic generating system generated output is subject to meteorological factor influence very big, is especially subject to solar irradiance and ambient temperature effect comparatively obvious.In recent years, domestic photovoltaic plant is installed total amount and is risen year by year, and when meteorological condition acute variation, the extensive photovoltaic plant of installing will have a strong impact on the stabilization of power grids, reduce the quality of power supply.In addition,, for photovoltaic generating system designer, the estimation generated output of building a power station also seems particularly important in advance.Therefore, set up accurate photovoltaic generating system output power model accurate estimation has become to its output power ever more important.

At present, from domestic and foreign literature, based on power station historical generating data and weather data, utilize the method for neural net model establishing estimation or prediction power station power comparatively general.But with respect to abroad, China's day irradiation Data Collection is started late, and wide geographic area historical data shortage, be difficult to by mass data training network.Therefore increasing scholar has proposed the power forecasting method in conjunction with numerical weather forecast and photovoltaic generating system physical model, and wherein comparatively common is single diode model.But this model parameter is more, solves inconvenience.

Summary of the invention

For the deficiency existing in prior art, the present invention seeks to the photovoltaic module model based on simplifying, disclose a kind of photovoltaic generating system output power model, and disclose the evaluation method of this model assessment photovoltaic generating system output power.

To achieve these goals, the present invention realizes by the following technical solutions:

An output power modeling method, is characterized in that, the method comprises the steps:

A. according to traditional solar battery sheet current-voltage characteristic model, set up photovoltaic module current-voltage characteristic model;

B. simplify above-mentioned photovoltaic module current-voltage characteristic model;

C. according to the photovoltaic module current-voltage characteristic model of simplifying, set up photovoltaic generating system output power model.

Described photovoltaic module current-voltage characteristic model, can be provided by following formula:

$I=I_{\mathrm{ph}}-I_0\{e^{\frac{q(V+R_{s}I)}{{\mathrm{nK}}_{b}T}}-1\}-\frac{V+R_{s}I}{R_{\mathrm{sh}}}$

Wherein: I and V are respectively solar battery sheet output current and voltage; I _phfor photogenerated current; I ₀for solar battery sheet P-N knot equivalent diode reverse saturation current; N is Diode Ideality Factor; Q is electron charge, 1.6 * 10 ^-19c; K _bfor Boltzmann constant; T is photovoltaic module working temperature; R _sand R _shbe respectively the inner equivalent series resistance of solar battery sheet and parallel resistance.

The photovoltaic module current-voltage characteristic formula of described simplification is provided by following formula:

$I=I_{\mathrm{SC}}-\frac{I_{\mathrm{SC}}{R}_{\mathrm{sh}}-V_{\mathrm{OC}}}{R_{\mathrm{sh}}}{(k+1)}^{(\frac{V+R_{s}I}{V_{\mathrm{OC}}}-1)}-\frac{V+R_{s}I}{R_{\mathrm{sh}}}$

I wherein _sCwith V _oCfor short-circuit current and the open-circuit voltage under photovoltaic module current environment of living in, k is model intermediate parameters.

Described photovoltaic generating system output power model, goes out photovoltaic generating system output power by the photovoltaic module current-voltage characteristic derivation of equation of simplifying, and is given by the following formula:

P _{MPP_Array}=N _pN _sV _MPPI _MPP

P in formula _{mPP_Array}for photovoltaic generating system output power, N _pwith N _sbe respectively the number of photovoltaic modules of parallel connection in photovoltaic array and the number of photovoltaic modules of series connection; V _mPPwith I _mPPbe respectively single photovoltaic module and work in voltage and the current value at maximum power point place.V _mPPwith I _mPPby following two solving simultaneous equations:

$I_{\mathrm{SC}}-I_{\mathrm{MPP}}-\frac{I_{\mathrm{SC}}-R_{\mathrm{sh}}-V_{\mathrm{OC}}}{R_{\mathrm{sh}}}{(k+1)}^{(\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{V_{\mathrm{OC}}}-1)}-\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{R_{\mathrm{sh}}}=0$

$V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP}}{R}_s+\frac{(V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_s)(I_{\mathrm{SC}}{R}_{\mathrm{sh}}-V_{\mathrm{OC}})}{V_{\mathrm{OC}}}{(k+1)}^{\left(\frac{V_{\mathrm{MPP}}+I_{\mathrm{MPP}}{R}_s-V_{\mathrm{OC}}}{V_{\mathrm{OC}}}\right)}\ln (k+1)=0.$

An output power evaluation method, comprises the steps:

A. create described photovoltaic generating system output power model;

B. obtain the characterisitic parameter under photovoltaic module standard test condition, by output power model parametric solution method, solving model parameter;

C. obtain original meteorologic parameter, comprise the horizontal irradiance in environment temperature and earth's surface;

D. meteorologic parameter is proofreaied and correct to the effective irradiation for photovoltaic module actual work temperature and absorption;

E. by the meteorologic parameter input model after proofreading and correct, by photovoltaic generating system output power method for solving, estimate photovoltaic generating system output power.

The method for solving of described output power model parameter, parametric solution method is as follows:

1) obtain the open-circuit voltage V of photovoltaic module under standard test condition _{oC, ref}, short-circuit current I _{sC, ref}, the voltage V of maximum power point place _{mPP, ref}with electric current I _{mPP, ref}, following two equations of simultaneous, numerical value iterative parameters R _swith R _sh, R _sand R _shbe respectively the inner equivalent series resistance of solar battery sheet and parallel resistance:

$V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s+(V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

$\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

$\frac{R_s}{R_{\mathrm{sh}}}+(\frac{R_s}{R_{\mathrm{sh}}}-1)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

${\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)}^{\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

2) solve parameters R _swith R _shafter, by following formula, solve parameter k under standard test condition, be designated as k _ref:

$k_{\mathrm{ref}}{=}^{(\frac{V_{\mathrm{MPP}}+I_{\mathrm{MPP}}{R}_s}{V_{\mathrm{OC},\mathrm{ref}}}-1)}\sqrt{\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}}.$

Described meteorologic parameter bearing calibration, the following formula of photovoltaic module mounting plane irradiation solves:

$S=(S_B+S_D{A}_T)\frac{\cos \mathrm{\θ}}{\cos {\mathrm{\θ}}_Z}+S_D(1-A_T)\left(\frac{1+{\cos \mathrm{\β}}_T}{2}\right)+S_H\mathrm{\ρ}\left(\frac{1-{\cos \mathrm{\β}}_T}{2}\right)$

S, S in formula _b, S _d, S _hbe respectively clinoplane irradiation, sun direct projection irradiation, scattering irradiation and the total irradiation of level; θ is solar incident angle, θ _zfor zenith angle, β _tfor clinoplane inclination angle; A _tfor anisotropic index, ρ is Ambient rate.

Photovoltaic module actual work temperature is calculated by following formula:

$T=T_{\mathrm{amb}}+\frac{T_{\mathrm{NOCT}}}{800}S$

Be wherein T _ambfor the environment temperature of weather forecast, T _nOCTfor photovoltaic module nominal operation temperature, T and S are respectively the effective irradiation of photovoltaic module temperature and absorption under any environment.

Described photovoltaic generating system output power method for solving, the method comprises the following steps:

1) obtain photovoltaic module short-circuit current temperature coefficient α, open-circuit voltage temperature coefficient β, open-circuit voltage irradiance correction factor a, calculates the photovoltaic module short-circuit current I under any irradiation and temperature environment by following formula _sCwith open-circuit voltage V _oC:

$I_{\mathrm{SC}}=I_{\mathrm{SC},\mathrm{ref}}[1+\mathrm{\α}(T-T_{\mathrm{ref}})]\frac{S}{S_{\mathrm{ref}}}$

$V_{\mathrm{OC}}=V_{\mathrm{OC},\mathrm{ref}}[1+a\ln \left(\frac{S}{S_{\mathrm{ref}}}\right)+\mathrm{\β}(T-T_{\mathrm{ref}})]$

T wherein _reffor the photovoltaic module temperature under standard test condition, 25 ℃, S _reffor irradiance under standard test condition, 1000W/m ², I _sCwith V _oCbe respectively photovoltaic module short-circuit current and open-circuit voltage in current environment.

2), based on photovoltaic module short-circuit current and open-circuit voltage under the above-mentioned any environment having solved, by following formula, solve any environment drag parameter k:

$\frac{\ln (k+1)}{\ln (k_{\mathrm{ref}}+1)}=\frac{V_{\mathrm{OC}}{T}_{\mathrm{ref}}}{V_{\mathrm{OC},\mathrm{ref}}T}$

3) solve parameters R _s, R _shafter k, according to described photovoltaic generating system output power model, can solve photovoltaic generating system output power.

The beneficial effect that the present invention reaches:

The present invention solves easy, can realize the output power of photovoltaic generating system is accurately estimated, helps Power Plant Design personnel to carry out performance analysis, and the weather forecast data based on degree of precision also can realize the prediction of photovoltaic generating system output power.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, describe the present invention in detail;

Fig. 1 is the photovoltaic generating system structural drawing of estimating in specific embodiment;

Fig. 2 is the output power modeling of invention photovoltaic generating system and evaluation method general flow chart;

Fig. 3 applies estimated power curve of the present invention and measured light photovoltaic generating system powertrace comparison diagram on September 23rd, 2013;

Fig. 4 applies estimated power curve of the present invention and measured light photovoltaic generating system powertrace comparison diagram on September 25th, 2013.

Embodiment

For technological means, creation characteristic that the present invention is realized, reach object and effect is easy to understand, below in conjunction with embodiment, further set forth the present invention.

The distributed grid-connected system of building up for Hohai University, the present invention's employing is exported DC power as the flow and method of Fig. 2 to this system and is estimated.

As shown in Figure 1, the TMS-PC05240W component string that this grid-connected system is produced by 44 Changzhou Trina Solar companies composes in parallel.The characterisitic parameter of this model photovoltaic module under standard test condition is as shown in the table:

Wherein open-circuit voltage irradiation correction factor a is outdoor measured value.Obtaining the open-circuit voltage V of photovoltaic module under standard test condition _{oC, ref}, short-circuit current I _{sC, ref}, the voltage V of maximum power point place _{mPP, ref}with electric current I _{mPP, ref}afterwards, following two equations of simultaneous, iterative parameters R _swith R _sh:

$V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s+(V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

$\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

$\frac{R_s}{R_{\mathrm{sh}}}+(\frac{R_s}{R_{\mathrm{sh}}}-1)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

${\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)}^{\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

Adopt numerical solution, solve R _svalue is 0.343 Ω, R _shvalue is 5956 Ω.

Solve parameters R _swith R _shafter, by following formula, solve parameter k under standard test condition, be designated as k _ref:

$k_{\mathrm{ref}}{=}^{(\frac{V_{\mathrm{MPP}}+I_{\mathrm{MPP}}{R}_s}{V_{\mathrm{OC},\mathrm{ref}}}-1)}\sqrt{\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}}.$

Try to achieve k _refvalue is 2.9301 * 10 ⁹.

In this specific embodiment, for ease of contrasting disclosed photovoltaic generating system output power appraising model and photovoltaic generating system real output, respectively on September 23rd, 2013 and September 25, recorded inverter and surveyed DC power data.Meanwhile, convenient for the purpose of, adopted the irradiance sensor with the coplanar installation of photovoltaic module, scene has recorded coplanar irradiance as the actual reception of the photovoltaic array irradiation after proofreading and correct; Adopt the on-the-spot assembly backboard temperature that records as the assembly working temperature after proofreading and correct.

Above-mentioned meteorologic parameter input of having proofreaied and correct had previously been solved to the photovoltaic generating system output power model of model parameter, simultaneous following formula, numerical solution goes out single output power of photovoltaic module:

$I_{\mathrm{SC}}-I_{\mathrm{MPP}}-\frac{I_{\mathrm{SC}}{R}_{\mathrm{sh}}-V_{\mathrm{OC}}}{R_{\mathrm{sh}}}{(k+1)}^{(\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{V_{\mathrm{OC}}}-1)}-\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{R_{\mathrm{sh}}}=0$

$V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP}}{R}_s+\frac{(V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_s)(I_{\mathrm{SC}}{R}_{\mathrm{sh}}-R_{\mathrm{OC}})}{V_{\mathrm{OC}}}{(k+1)}^{\left(\frac{v_{\mathrm{mpp}}+I_{\mathrm{mpp}}-V_{\mathrm{OC}}}{V_{\mathrm{OV}}}\right)}\ln (k+1)=0$

By required single output power of photovoltaic module, by following formula, estimate photovoltaic generating system output power again:

P _{MPP_Array}=4×11×V _MPPI _MPP

As shown in Figure 3, Figure 4, September 23,25 days, powertrace and the measured light photovoltaic generating system powertrace of the calculating of photovoltaic generating system output power appraising model relatively showed, estimation curve of the present invention and measured curve matching are good.Wherein whole day power percentage error, related coefficient are as shown in the table:

From table, the present invention can realize the accurate estimation to photovoltaic generating system output DC power, meets scientific research and practical implementation.

Wherein, average percent error (MPE) is solved by following formula:

In formula, n is whole day photovoltaic generating system power sample sum.

Related coefficient (R) is solved by following formula:

More than show and described ultimate principle of the present invention and principal character and advantage of the present invention.The technician of the industry should understand; the present invention is not restricted to the described embodiments; that in above-described embodiment and instructions, describes just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.

Claims (7)

1. photovoltaic generating system output power modeling method, is characterized in that, comprises the steps:

A. according to traditional solar battery sheet current-voltage characteristic model, set up photovoltaic module current-voltage characteristic model;

B. simplify above-mentioned photovoltaic module current-voltage characteristic model;

C. according to the photovoltaic module current-voltage characteristic model of simplifying, set up photovoltaic generating system output power model.

2. photovoltaic generating system output power modeling method according to claim 1, is characterized in that, in step a, single photovoltaic module current-voltage characteristic model is provided by following equation:

$I=I_{\mathrm{ph}}-I_0\{e^{\frac{q(V+R_{s}I)}{{\mathrm{nK}}_{b}T}}-1\}-\frac{V+R_{s}I}{R_{\mathrm{sh}}}$

Wherein: I and V are respectively solar battery sheet output current and voltage; I _phfor photogenerated current; I ₀for solar battery sheet P-N knot equivalent diode reverse saturation current; N is Diode Ideality Factor; Q is electron charge, 1.6 * 10 ^-19c; K _bfor Boltzmann constant; T is photovoltaic module working temperature; R _sand R _shbe respectively the inner equivalent series resistance of solar battery sheet and parallel resistance.

3. photovoltaic generating system output power modeling method according to claim 2, is characterized in that, the equation of the photovoltaic module current-voltage characteristic model of simplification is as follows:

$I=I_{\mathrm{SC}}-\frac{I_{\mathrm{SC}}{R}_{\mathrm{sh}}-V_{\mathrm{OC}}}{R_{\mathrm{sh}}}{(k+1)}^{(\frac{V+R_{s}I}{V_{\mathrm{OC}}}-1)-\frac{V+R_{s}I}{R_{\mathrm{sh}}}}$

I wherein _sCwith V _oCfor short-circuit current and the open-circuit voltage under photovoltaic module current environment of living in, k is model intermediate parameters.

4. photovoltaic generating system output power modeling method according to claim 3, is characterized in that, photovoltaic generating system output power model is by following formula:

P _{MPP_Array}=N _pN _sV _MPPI _MPP

P wherein _{mPP_Array}for photovoltaic generating system output power, N _pwith N _sbe respectively the number of photovoltaic modules of parallel connection in photovoltaic array and the number of photovoltaic modules of series connection; V _mPPwith I _mPPbe respectively single photovoltaic module and work in voltage and the current value at maximum power point place; V _mPPwith I _mPPby following two solving simultaneous equations:

$I_{\mathrm{SC}}-I_{\mathrm{MPP}}-\frac{I_{\mathrm{SC}}-R_{\mathrm{sh}}-V_{\mathrm{OC}}}{R_{\mathrm{sh}}}{(k+1)}^{(\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{V_{\mathrm{OC}}}-1)}-\frac{V_{\mathrm{MPP}}+R_s{I}_{\mathrm{MPP}}}{R_{\mathrm{sh}}}=0$

$V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP}}{R}_s+\frac{(V_{\mathrm{MPP}}-I_{\mathrm{MPP}}{R}_s)(I_{\mathrm{SC}}{R}_{\mathrm{sh}}-V_{\mathrm{OC}})}{V_{\mathrm{OC}}}{(k+1)}^{\left(\frac{V_{\mathrm{MPP}}+I_{\mathrm{MPP}}{R}_s-V_{\mathrm{OC}}}{V_{\mathrm{OC}}}\right)}\ln (k+1)=0.$

5. the photovoltaic generating system output power evaluation method based on photovoltaic generating system output power modeling method claimed in claim 1, is characterized in that, comprises the steps:

A. create photovoltaic generating system output power model;

B. obtain the characterisitic parameter under photovoltaic module standard test condition, by output power model parametric solution method, solving model parameter;

C. obtain original meteorologic parameter, comprise the horizontal irradiance in environment temperature and earth's surface;

D. meteorologic parameter is proofreaied and correct to the effective irradiation for photovoltaic module actual work temperature and absorption;

E. by the meteorologic parameter input model after proofreading and correct, by photovoltaic generating system output power method for solving, estimate photovoltaic generating system output power.

6. photovoltaic generating system output power evaluation method according to claim 5, is characterized in that, the method for solving of output power model parameter is as follows:

1) obtain the open-circuit voltage V of photovoltaic module under standard test condition _{oC, ref}, short-circuit current I _{sC, ref}, the voltage V of maximum power point place _{mPP, ref}with electric current I _{mPP, ref}, following two equations of simultaneous, numerical value iterative parameters R _swith R _sh, R _sand R _shbe respectively the inner equivalent series resistance of solar battery sheet and parallel resistance:

$V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s+(V_{\mathrm{MPP},\mathrm{ref}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

$\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

$\frac{R_s}{R_{\mathrm{sh}}}+(\frac{R_s}{R_{\mathrm{sh}}}-1)\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}$

${\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP},\mathrm{ref}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}\right)}^{\left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)}$

$\ln \left(\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}{V_{\mathrm{MPP},\mathrm{ref}}+I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{OC},\mathrm{ref}}}\right)=0$

2) solve parameters R _swith R _shafter, by following formula, solve parameter k under standard test condition, be designated as k _ref:

$k_{\mathrm{ref}}{=}^{(\frac{V_{\mathrm{MPP}}+I_{\mathrm{MPP}}{R}_s}{V_{\mathrm{OC},\mathrm{ref}}}-1)}\sqrt{\frac{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_{\mathrm{sh}}-I_{\mathrm{MPP},\mathrm{ref}}{R}_s-V_{\mathrm{MPP}}}{I_{\mathrm{SC},\mathrm{ref}}{R}_{\mathrm{sh}}-V_{\mathrm{OC},\mathrm{ref}}}}.$

7. photovoltaic generating system output power evaluation method according to claim 5, is characterized in that, described photovoltaic generating system output power method for solving, comprises the steps:

1) obtain photovoltaic module short-circuit current temperature coefficient α, open-circuit voltage temperature coefficient β, open-circuit voltage irradiance correction factor a, calculates the photovoltaic module short-circuit current I under any irradiation and temperature environment by following formula _sCwith open-circuit voltage V _oC:

$I_{\mathrm{SC}}=I_{\mathrm{SC},\mathrm{ref}}[1+\mathrm{\α}(T-T_{\mathrm{ref}})]\frac{S}{S_{\mathrm{ref}}}$

$V_{\mathrm{OC}}=V_{\mathrm{OC},\mathrm{ref}}[1+a\ln \left(\frac{S}{S_{\mathrm{ref}}}\right)+\mathrm{\β}(T-T_{\mathrm{ref}})]$

T wherein _reffor the photovoltaic module temperature under standard test condition, 25 ℃, S _reffor irradiance under standard test condition, 1000W/m ², T and S are respectively the effective irradiation of photovoltaic module temperature and absorption under any environment, I _sCwith V _oCbe respectively photovoltaic module short-circuit current and open-circuit voltage in current environment;

2), based on photovoltaic module short-circuit current and open-circuit voltage under the above-mentioned any environment having solved, by following formula, solve any environment drag parameter k:

$\frac{\ln (k+1)}{\ln (k_{\mathrm{ref}}+1)}=\frac{V_{\mathrm{OC}}{T}_{\mathrm{ref}}}{V_{\mathrm{OC},\mathrm{ref}}T}$

3) solve parameters R _s, R _shafter k, according to photovoltaic generating system output power model, solve photovoltaic generating system output power.

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