CN102723740A - Stable MPPT (Maximum Power Point Tracking) control system and method of single-stage photovoltaic inverter - Google Patents

Abstract

The invention provides a stable MPPT (Maximum Power Point Tracking) control system and method of a single-stage photovoltaic inverter. The stable MPPT control system comprises a solar panel, a photovoltaic inverter, a power grid and an MPPT controller, wherein the solar panel, the photovoltaic inverter and the power grid are sequentially connected with one another; and the MPPT controller is respectively connected with the solar panel and the photovoltaic inverter. According to the stable MPPT control method, a novel voltage ring controller is adopted and comprises a proportional integral (PI) control module, a pole compensation module and a notching filter module, and the voltage ring controller and a current ring controller adopt a same control period, thus ensuring the operation stability of a single-stage inversion system and guaranteeing the single-stage inversion system to output electric energy with good quality; and an MPPT (Maximum Power Point Tracking) variable-step voltage disturbance method is adopted, a proportional coefficient is regulated to guarantee better dynamic response and steady-state performance of MPPT, and thus the use efficiency of the solar panel is improved.

Description

The single-stage photovoltaic DC-to-AC converter is stablized MPPT control system and method

Technical field

The invention belongs to the photovoltaic power generation technology field, be specifically related to a kind of single-stage photovoltaic DC-to-AC converter and stablize MPPT control system and method.

Background technology

In solar grid-connected electricity generation system; Solar cell is a kind of semiconductor device that luminous energy is directly changed into electric energy; Under certain luminous energy; How effectively to increase the power output of solar cell, thereby make full use of solar energy, the generating efficiency that improves whole solar grid-connected electricity generation system is significant.

Through the solar cell characteristics of output power is studied, find that solar cell power output P is relevant with ambient temperature T with intensity of illumination W, as shown in Figure 1, be the P-U characteristic curve under the different W of identical T, wherein, U is the solar cell output voltage; Fig. 2 is the P-U characteristic curve under the different T of identical W.As can beappreciated from fig. 1, the solar cell peak power output strengthens with intensity of illumination and becomes big, and, under same photoenvironment, have unique peak power output point.In peak power output point left side, power output rises with the solar cell output voltage and is the approximately linear ascendant trend; After arriving peak power output point, power output begins quick decline, and decrease speed is much larger than the rate of climb.Among Fig. 2, the total variation tendency of solar cell power output is similar with Fig. 1.

Therefore; Solar cell power output and intensity of illumination and ambient temperature are in close relations; When external environment condition changed, the solar cell power output also can produce bigger variation, how photovoltaic generating system was controlled; Making solar cell working near peak power output point, is the effective means that improves solar battery efficiency.

MPPT (Maximum Power Point Tracking; MPPT maximum power point tracking) be to adopt more a kind of solar cell power points control strategy at present; Operating state through the real time altering grid-connected system; The peak power output point of tracking solar battery, thus realize the output of solar cell maximum power.Concrete; Through changing controlled quentity controlled variable; The output voltage of solar cell is changed,, judge the position of present operating point on the P-U characteristic curve through the difference of power output before and after changing to output voltage; And then judge the variation pattern of next step controlled quentity controlled variable, thereby make solar cell working point gradually to the peak power output point near.

At present; Adopt the peak power output point of the existing controller working voltage method of perturbation tracking solar battery of MPPT control strategy; It is lower to have the disturbance following rate; And this bat that calculates is prone to deviation and causes incorrect polarity with the solar panel output voltage difference Δ u of last bat, and promptly the positive and negative mistake of Δ u can't guarantee effectively that the solar panel steady operation is near peak power output point; And can't follow the tracks of the violent photoenvironment of variation fast, thereby reduce the solar panel service efficiency.

Summary of the invention

Defective to the prior art existence; The present invention provides a kind of single-stage photovoltaic DC-to-AC converter to stablize MPPT control system and method; Voltage controller is based on dc capacitor voltage and the modeling of outputting inductance electric current; Voltage and electric current loop adopt identical control cycle, adopt novel Voltage loop controller, comprising: proportional integral PI controls, adds pole compensation and notch filter combination; Thereby the stable operation of assurance single-stage inversion system is stopped direct voltage avalanche problem in the solar panel P-U characteristic curve maximum power point left and right sides; In addition, adopt the variable step voltage disturbance method of Mppt, through the resize ratio coefficient, can guarantee the good dynamic response and the steady-state behaviour of MPPT maximal power tracing, thereby improve the solar panel service efficiency.

The technical scheme that the present invention adopts is following:

The present invention provides a kind of single-stage photovoltaic DC-to-AC converter to stablize the MPPT control system, comprises solar panel, photovoltaic DC-to-AC converter, electrical network and MPPT controller; Said solar panel, said photovoltaic DC-to-AC converter and said electrical network are connected in order; Said MPPT controller is connected with said photovoltaic DC-to-AC converter with said solar panel respectively.

Preferably, said photovoltaic DC-to-AC converter comprises three-phase inverting circuit, filter circuit and the transforming circuit of series connection; And/or said MPPT controller is a dsp controller.

The present invention provides a kind of method that above-mentioned single-stage photovoltaic DC-to-AC converter is stablized the MPPT control system of using, and said method comprising the steps of:

S1, said MPPT controller is gathered the actual output voltage u of said solar panel _DcWith actual output current i _Pv, to handle through the voltage disturbance ring, output is as the voltage given u of voltage control loop _{Dc_ref}

S2, said MPPT controller is with the Voltage Feedback u of said solar panel _{Dc_fb}With u _{Dc_ref}Export to said voltage control loop, handle through said voltage control loop, output is as the given i of current regulator d shaft current _{D_ref}

S3, said MPPT controller gather the current three-phase current i that is incorporated into the power networks of said photovoltaic DC-to-AC converter _a, i _bAnd i _c, based on PARK and CLARK conversion principle, convert three phase static coordinate system abc into two phase rest frame α β, converting said two phase rest frame α β into two cordic phase rotators again is dq, calculates d shaft current i _dWith q shaft current i _q

S4, the i that S2 is obtained _{D_ref}The i that obtains with S3 _dDifference export to said current regulator, output d shaft voltage u _{M_d}Said controller is set to pure active power output, the given i of reactive current _{Q_ref}=0, with i _qDifference export to said current regulator, output q shaft voltage u _{M_q}

S5, said controller carry out coordinate system inversion conversion, and being about to two cordic phase rotators is that dq converts two phase rest frame α β into, converts two phase rest frame α β into three phase static coordinate system abc again, with u _{M_d}And u _{M_q}Be converted to three-phase control voltage u _{M_a}, u _{M_b}And u _{M_c}Adopt the SVPWM space vector pulse width modulation to obtain three-phase modulations ripple PWM then, export the pipe module I GBT of said photovoltaic DC-to-AC converter to.

Preferably, among the S1, said voltage disturbance ring processing procedure is specially:

S11 sets the voltage given u of said voltage control loop _{Dc_ref}Initial value and meet variable sign;

S12 sets sample frequency, gathers the actual output voltage u of the solar panel of current bat by this sample frequency _Dc(k) and actual output current i _Pv(k), calculate the power output P (k) of the solar panel of current bat then, wherein, P (k)=u _Dc(k) * i _Pv(k);

S13 obtains the direct voltage set-point u of the solar panel that the power output P (k-1), preceding 1 of preceding 1 solar panel clapped claps _{Dc_ref}(k-1) and the direct voltage set-point u of preceding 2 solar panels clapped _{Dc_ref}(k-2); Calculate Δ P and Δ u then, wherein, Δ P=P (k)-P (k-1), Δ u=u _{Dc_ref}(k-1)-u _{Dc_ref}(k-2);

S14 judges whether Δ P equals 0, if judged result is for being that then the sign assignment 0, carries out S17 then; If judged result is then carried out S15 for not;

S15 further judges whether to satisfy the condition of Δ P＞0 and Δ u＜0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is then carried out S16 for not;

S16 further judges whether to satisfy the condition of Δ P＜0 and Δ u＞0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is that then sign assignment-1 does not carry out 17 then;

S17 calculates the voltage given u of the said voltage control loop that current bat need export according to formula (1) _{Dc_ref}(k);

u _{Dc_ref}(k)=u _{Dc_ref}(k-1)-sign * u _Step* (K _Mppt* Δ P) formula (1)

Wherein, u _Step---voltage disturbance step value, K _Mppt---proportionality coefficient;

S18 when arriving the sampling period of next bat, makes k=k+1, repeats S12-S17.

Preferably, said voltage control loop processing procedure is specially:

Handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through proportional controller K _pCalculate ratio output pr _Out,

Through integral controller

Calculate integration output in _OutPr _OutWith in _OutAddition, output pi _OutPi _OutThrough 1 limit Handle, output is as sys _OutCarry out the feedforward compensation of solar panel output current again, output valve is passed through secondary notch filter G again _Notch(s) handle, output is as the given i of current regulator d shaft current _{D_ref}Wherein,

When being the 50Hz electrical network, ω=100 π rad/s.

Preferably, after the S2, also comprise:

Handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through Voltage loop controller D _{V_all}(s), output i _{D_ref}Given as electric current loop d shaft current; i _{D_ref}With inductance d shaft current feedback i _dDifference through current loop controller D _i(s), output u _{M_d}u _{M_d}Through hardware inductance module

Export actual d shaft current i _di _dWith i _PvPoor, output actual capacitance i _DcAgain through the hardware capacitance module

Output u _Dc

Preferably, said voltage control loop is identical with the control cycle of said current regulator.

Beneficial effect of the present invention is following:

Single-stage photovoltaic DC-to-AC converter provided by the invention is stablized MPPT control system and method; Have following innovation: (1) is based on inverter dc capacitor voltage and the modeling of outputting inductance electric current; The Voltage loop control system is passed through to adopt identical control cycle with current regulator, thereby has improved the voltage control dynamic response.(2) adopt novel Voltage loop controller; Comprise: proportional integral PI controls, adds pole compensation and notch filter combination; Thereby the stable operation of assurance single-stage inversion system is stopped direct voltage avalanche problem in the solar panel P-U characteristic curve maximum power point left and right sides.Therefore, guarantee single-stage inverter maximal power tracing stability and the highest tracking efficient and good electric energy output.(3) the variable step voltage disturbance method of employing Mppt through the resize ratio coefficient, can guarantee the good dynamic response and the steady-state behaviour of MPPT maximal power tracing.

Description of drawings

Fig. 1 is the solar panel P-U characteristic curve under the equivalent environment temperature different illumination intensity in the prior art;

Fig. 2 is the solar panel P-U characteristic curve under the identical intensity of illumination varying environment temperature in the prior art;

Fig. 3 is the overall structure sketch map that single-stage photovoltaic DC-to-AC converter provided by the invention is stablized the MPPT control system;

Fig. 4 is the process chart of voltage disturbance ring provided by the invention;

Fig. 5 is the structural representation of voltage control loop provided by the invention;

Fig. 6 is the structural representation of electric current and voltage control ring provided by the invention;

Fig. 7 is inverter applications MPPT control system operation provided by the invention one day solar panel power output Pdc and an inverter power output Pacc curve chart;

Fig. 8 is applied solar cell panel voltages and a change of time curve among Fig. 7.

When Fig. 9 generates electricity for the actual measurement photovoltaic DC-to-AC converter, direct voltage and output current wave.

Embodiment

As shown in Figure 3, single-stage photovoltaic DC-to-AC converter provided by the invention is stablized the MPPT control system, it is characterized in that, comprises solar panel, photovoltaic DC-to-AC converter, electrical network and MPPT controller; Said solar panel, said photovoltaic DC-to-AC converter and said electrical network are connected in order; Said MPPT controller is connected with said photovoltaic DC-to-AC converter with said solar panel respectively.Wherein, said photovoltaic DC-to-AC converter comprises three-phase inverting circuit, filter circuit and the transforming circuit of series connection; And/or said MPPT controller is a dsp controller.

Use above-mentioned single-stage photovoltaic DC-to-AC converter and stablize the MPPT control system, single-stage photovoltaic DC-to-AC converter provided by the invention is stablized the MPPT control method and may further comprise the steps:

S1, said MPPT controller is gathered the actual output voltage u of said solar panel _DcWith actual output current i _Pv, to handle through the voltage disturbance ring, output is as the voltage given u of voltage control loop _{Dc_ref}

As shown in Figure 4, be the process chart of voltage disturbance ring provided by the invention, voltage disturbance ring processing procedure is specially:

S11 sets the voltage given u of said voltage control loop _{Dc_ref}Initial value and meet variable sign;

Wherein, meet variable sign only to be composed three kinds of values: 0,1 and-1.

S12 sets sample frequency, gathers the actual output voltage u of the solar panel of current bat by this sample frequency _Dc(k) and actual output current i _Pv(k), calculate the power output P (k) of the solar panel of current bat then, wherein, P (k)=u _Dc(k) * i _Pv(k);

S13 obtains the direct voltage set-point u of the solar panel that the power output P (k-1), preceding 1 of preceding 1 solar panel clapped claps _{Dc_ref}(k-1) and the direct voltage set-point u of preceding 2 solar panels clapped _{Dc_ref}(k-2); Calculate Δ P and Δ u then, wherein, Δ P=P (k)-P (k-1), Δ u=u _{Dc_ref}(k-1)-u _{Dc_ref}(k-2);

In this step,, use u in the calculating voltage difference _{Dc_ref}Replace u _Dc, that is: make the direct voltage set-point u of preceding 1 solar panel clapped _{Dc_ref}(k-1) with the direct voltage set-point u of preceding 2 solar panels clapped _{Dc_ref}(k-2) poor, cause Δ u value deviation or incorrect polarity in the time of can avoiding there is big voltage ripple, and then influence accuracy and stability that disturbance moves by voltage sample deviation or direct current.

S14 judges whether Δ P equals 0, if judged result is for being that then the sign assignment 0, carries out S17 then; If judged result is then carried out S15 for not;

S15 further judges whether to satisfy the condition of Δ P＞0 and Δ u＜0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is then carried out S16 for not;

S16 further judges whether to satisfy the condition of Δ P＜0 and Δ u＞0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is that then sign assignment-1 does not carry out 17 then;

S17 calculates the voltage given u of the said voltage control loop that current bat need export according to formula (1) _{Dc_ref}(k);

u _{Dc_ref}(k)=u _{Dc_ref}(k-1)-sign * u _Step* (K _Mppt* Δ P) formula (1)

Wherein, u _Step---voltage disturbance step value, K _Mppt---proportionality coefficient;

S18 when arriving the sampling period of next bat, makes k=k+1, repeats S 12-S17.

Concrete, in conjunction with Fig. 1 or Fig. 2, divide following three kinds of briefings:

(1) when Δ P=0; Show that the solar panel work at present is at maximum power point (mpp); So; Make that sign is 0, the voltage given of the voltage control loop that current bat need export is equated with the voltage given of the voltage control loop of last bat output, that is: do not change this bat solar panel operating state;

(2) when satisfying condition 1: Δ P＞0 and Δ u＜0; Or condition 2: Δ P＜0 and Δ u＞0 o'clock; Show the right side of solar panel work at present at maximum power point (mpp); Therefore, the sign assignment is 1, makes the voltage given of the voltage given of the voltage control loop that current bat need export less than the voltage control loop of last bat output; The power output of solar panel is moved to left, and gradually near maximum power point (mpp);

(3) when Δ P/ Δ u＞0; Show the left side of solar panel work at present at maximum power point (mpp); Therefore, the sign assignment is-1, makes the voltage given of the voltage given of the voltage control loop that current bat need export greater than the voltage control loop of last bat output; The power output of solar panel is moved to right, and gradually near maximum power point (mpp).

In this step, adopt the variable step voltage disturbance method of Mppt,, can guarantee the good dynamic response and the steady-state behaviour of MPPT maximal power tracing through the resize ratio coefficient.

S2, said MPPT controller is with the Voltage Feedback u of said solar panel _{Dc_fb}With u _{Dc_ref}Export to said voltage control loop, handle through said voltage control loop, output is as the given i of current regulator d shaft current _{D_ref}

As shown in Figure 5, be the structural representation of voltage control loop provided by the invention, the voltage control loop processing procedure is specially:

Handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through proportional controller K _pCalculate ratio output pr _Out,

Through integral controller

Calculate integration output in _OutPr _OutWith in _OutAddition, output pi _OutPi _OutThrough 1 limit Handle, output is as sys _OutCarry out the feedforward compensation of solar panel output current again, output valve is passed through secondary notch filter G again _Notch(s) handle, output is as the given i of current regulator d shaft current _{D_ref}Wherein,

When being the 50Hz electrical network, ω=100 π rad/s.

In this step, pi _OutCan guarantee that direct voltage does not have clean poor tracking; Limit is handled and is act as: with the high-frequency signal filtering, can eliminate under the stable state to current regulator and inject the high-frequency harmonic component.Have suffered Cheng Zuowei Voltage loop control system D _{V_all}(s); The Voltage loop control system has improved the voltage control dynamic response through adopting and the same control cycle of current regulator, through design excellent control device parameter; Guarantee that but single-stage inverter stable operation is in the left and right sides of cell panel power voltage PV curve maximum power point; Make pole compensation and filter on the algorithm simultaneously, guaranteed only to inject small harmonic wave to current regulator under the stable state, basically the actual current harmonic wave is not had influence.Therefore, guarantee single-stage inverter maximal power tracing stability and the highest tracking efficient and good electric energy output.

Shown in Fig. 6, after the S2, also comprise: handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through Voltage loop controller D _{V_all}(s), output i _{M_d}i _{M_d}With solar panel output current i _PvAddition, output i _{D_ref}i _{D_ref}With inductance d shaft current feedback i _dDifference through current loop controller D _i(s), output u _{M_d}u _{M_d}Through hardware inductance module

Export actual d shaft current i _di _dWith i _PvPoor, output actual capacitance i _DcAgain through the hardware capacitance module

Output u _Dc

S3, said MPPT controller gather the current three-phase current i that is incorporated into the power networks of said photovoltaic DC-to-AC converter _a, i _bAnd i _c, based on PARK and CLARK conversion principle, convert three phase static coordinate system abc into two phase rest frame α β, converting said two phase rest frame α β into two cordic phase rotators again is dq, calculates d shaft current i _dWith q shaft current i _q

S4, the i that S2 is obtained _{D_ref}The i that obtains with S3 _dDifference export to said current regulator, output d shaft voltage u _{M_d}Said controller is set to pure active power output, the given i of reactive current _{Q_ref}=0, with i _qDifference export to said current regulator, output q shaft voltage u _{M_q}

S5, said controller carry out coordinate system inversion conversion, and being about to two cordic phase rotators is that dq converts two phase rest frame α β into, converts two phase rest frame α β into three phase static coordinate system abc again, with u _{M_d}And u _{M_q}Be converted to three-phase control voltage u _{M_a}, u _{M_b}And u _{M_c}Adopt the SVPWM space vector pulse width modulation to obtain three-phase modulations ripple PWM then, export the pipe module I GBT of said photovoltaic DC-to-AC converter to.

Adopt space vector pulse width modulation SVPWM strategy, have the following advantages 1) improve the direct voltage utilance, assurance can adapt to the direct voltage scope of broad; 2) can reduce the harmonic current (as 3,6,9... subharmonic) of 3 multiples greatly, can reduce the wastage and ensure to electrical network better electric energy is provided.

In addition, among the present invention, voltage control loop is identical with the control cycle of current regulator, the control cycle of voltage control loop and the control cycle of current regulator has been shown among Fig. 3 has been 100us, has improved the voltage control dynamic response.Need to prove; Among the present invention; Control cycle be meant voltage control loop or current regulator to the voltage of the digital signals format that receives or the cycle that current signal carries out s operation control, for example: every 100us makes 1 signal sampling, and promptly the sampling period is 100us; The every 100us of control ring does a controller computing, and then control cycle is 100us.

Use single-stage photovoltaic DC-to-AC converter provided by the invention and stablize MPPT control system and method, photovoltaic DC-to-AC converter is carried out actual test, Fig. 7 shows solar panel power output P _DcWith inverter power output Pac curve, wherein, 1 represents solar panel power output P _DcWith the change of time curve, 2 represent inverter power output P _AcWith the change of time curve; Fig. 8 shows solar cell panel voltages and change of time curve.When Fig. 9 generates electricity for the actual measurement photovoltaic DC-to-AC converter, direct voltage and output current wave.Can find out that in conjunction with Fig. 7, Fig. 8 and Fig. 9 after using single-stage photovoltaic DC-to-AC converter of the present invention and stablizing MPPT control system and method, solar panel direct voltage and power output are all highly stable.

In sum; Single-stage photovoltaic DC-to-AC converter provided by the invention is stablized MPPT control system and method; Have following innovation: the variable step voltage disturbance method of Mppt is adopted in (1), through the resize ratio coefficient, can guarantee the good dynamic response and the steady-state behaviour of MPPT maximal power tracing.(2) the Voltage loop control system is through adopting and the same control cycle of current regulator; Improved the voltage control dynamic response; Through design excellent control device parameter, but guarantee single-stage inverter stable operation, make pole compensation and filter on the while algorithm in the left and right sides of cell panel power voltage PV curve maximum power point; Guaranteed only to inject small harmonic wave to current regulator under the stable state, basically the actual current harmonic wave has not been had influence.Therefore, guarantee single-stage inverter maximal power tracing stability and the highest tracking efficient and good electric energy output.

The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; Can also make some improvement and retouching, these improvement and retouching also should be looked protection scope of the present invention.

Claims (7)

1. a single-stage photovoltaic DC-to-AC converter is stablized the MPPT control system, it is characterized in that, comprises solar panel, photovoltaic DC-to-AC converter, electrical network and MPPT controller; Said solar panel, said photovoltaic DC-to-AC converter and said electrical network are connected in order; Said MPPT controller is connected with said photovoltaic DC-to-AC converter with said solar panel respectively.

2. single-stage photovoltaic DC-to-AC converter according to claim 1 is stablized the MPPT control system, it is characterized in that, said photovoltaic DC-to-AC converter comprises three-phase inverting circuit, filter circuit and the transforming circuit of series connection; And/or said MPPT controller is a dsp controller.

3. an application rights requires each said single-stage photovoltaic DC-to-AC converter of 1-2 to stablize the method for MPPT control system, it is characterized in that, said method comprising the steps of:

S1, said MPPT controller is gathered the actual output voltage u of said solar panel _DcWith actual output current i _Pv, to handle through the voltage disturbance ring, output is as the voltage given u of voltage control loop _{Dc_ref}

S2, said MPPT controller is with the Voltage Feedback u of said solar panel _{Dc_fb}With u _{Dc_ref}Export to said voltage control loop, handle through said voltage control loop, output is as the given i of current regulator d shaft current _{D_ref}

S3, said MPPT controller gather the current three-phase current i that is incorporated into the power networks of said photovoltaic DC-to-AC converter _a, i _bAnd i _c, based on PARK and CLARK conversion principle, convert three phase static coordinate system abc into two phase rest frame α β, converting said two phase rest frame α β into two cordic phase rotators again is dq, calculates d shaft current i _dWith q shaft current i _q

S4, the i that S2 is obtained _{D_ref}The i that obtains with S3 _dDifference export to said current regulator, output d shaft voltage u _{M_d}Said controller is set to pure active power output, the given i of reactive current _{Q_ref}=0, with i _qDifference export to said current regulator, output q shaft voltage u _{M_q}

S5, said controller carry out coordinate system inversion conversion, and being about to two cordic phase rotators is that dq converts two phase rest frame α β into, converts two phase rest frame α β into three phase static coordinate system abc again, with u _{M_d}And u _{M_q}Be converted to three-phase control voltage u _{M_a}, u _{M_b}And u _{M_c}Adopt the SVPWM space vector pulse width modulation to obtain three-phase modulations ripple PWM then, export the pipe module I GBT of said photovoltaic DC-to-AC converter to.

4. method according to claim 3 is characterized in that, among the S1, said voltage disturbance ring processing procedure is specially:

S11 sets the voltage given u of said voltage control loop _{Dc_ref}Initial value and meet variable sign;

S12 sets sample frequency, gathers the actual output voltage u of the solar panel of current bat by this sample frequency _Dc(k) and actual output current i _Pv(k), calculate the power output P (k) of the solar panel of current bat then, wherein, P (k)=u _Dc(k) * i _Pv(k);

S13 obtains the direct voltage set-point u of the solar panel that the power output P (k-1), preceding 1 of preceding 1 solar panel clapped claps _{Dc_ref}(k-1) and the direct voltage set-point u of preceding 2 solar panels clapped _{Dc_ref}(k-2); Calculate Δ P and Δ u then, wherein, Δ P=P (k)-P (k-1), Δ u=u _{Dc_ref}(k-1)-u _{Dc_ref}(k-2);

S14 judges whether Δ P equals 0, if judged result is for being that then the sign assignment 0, carries out S17 then; If judged result is then carried out S15 for not;

S15 further judges whether to satisfy the condition of Δ P＞0 and Δ u＜0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is then carried out S16 for not;

S16 further judges whether to satisfy the condition of Δ P＜0 and Δ u＞0, if judged result is for being that then the sign assignment 1, carries out S17 then; If judged result is that then sign assignment-1 does not carry out 17 then;

S17 calculates the voltage given u of the said voltage control loop that current bat need export according to formula (1) _{Dc_ref}(k);

u _{Dc_ref}(k)=u _{Dc_ref}(k-1)-sign * u _Step* (K _Mppt* Δ P) formula (1)

Wherein, u _Step---voltage disturbance step value, K _Mppt---proportionality coefficient;

S18 when arriving the sampling period of next bat, makes k=k+1, repeats S 12-S17.

5. method according to claim 3 is characterized in that, among the S2, said voltage control loop processing procedure is specially:

Handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through proportional controller K _pCalculate ratio output pr _Out, Through integral controller

Calculate integration output in _OutPr _OutWith in _OutAddition, output pi _OutPi _OutThrough 1 limit

Handle, output is as sysy _OutCarry out the feedforward compensation of solar panel output current again, output valve is passed through secondary notch filter G again _Notch(s) handle, output is as the given i of current regulator d shaft current _{D_ref}Wherein,

When being the 50Hz electrical network, ω=100 π rad/s.

6. method according to claim 3 is characterized in that, after the S2, also comprises:

Handle the given u of output voltage through said voltage disturbance ring _{Dc_ref}, u _{Dc_ref}With Voltage Feedback u _{Dc_fb}Subtract each other, obtain difference

Through Voltage loop controller D _{V_all}(s), output i _{D_ref}Given as electric current loop d shaft current; i _{D_ref}With inductance d shaft current feedback i _dDifference through current loop controller D _i(s), output u _{M_d}u _{M_d}Through hardware inductance module

Export actual d shaft current i _di _dWith i _PvPoor, output actual capacitance i _DcAgain through the hardware capacitance module

Output u _Dc

7. method according to claim 3 is characterized in that, said voltage control loop is identical with the control cycle of said current regulator.

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