CN114050732A - Photovoltaic power generation grid-connected inverter control method based on active damping - Google Patents

Photovoltaic power generation grid-connected inverter control method based on active damping Download PDF

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CN114050732A
CN114050732A CN202111260077.9A CN202111260077A CN114050732A CN 114050732 A CN114050732 A CN 114050732A CN 202111260077 A CN202111260077 A CN 202111260077A CN 114050732 A CN114050732 A CN 114050732A
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inverter
grid
phase
voltage
mathematical model
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李宁
肖子涵
张世乾
郑爱香
柳明
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Xian University of Technology
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Xian University of Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

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Abstract

The invention discloses a photovoltaic power generation grid-connected inverter control method based on active damping, which comprises the steps of collecting inverter signals, carrying out Park conversion, establishing a Hamilton system mathematical model, namely a PCHD mathematical model, according to an LCL type grid-connected inverter, calculating the passive control rate U of a system through the PCHD mathematical model, and adopting U to control the inverter to obtain the components U of the system control rate on the d axis and the q axis of a two-phase rotating coordinate systemdAnd UqWill U isd，UqTransforming into a two-phase static coordinate system to obtain UαAnd UβWill U isα、UβProcessed alpha and beta axis modulation voltage U obtained from input trapα ’、Uβ ’Will modulate the voltage Uα ’、Uβ ’And inputting the duty ratio signal into a driving protection circuit of the LCL type three-phase grid-connected inverter to control the on and off of the switching tube of the inverter circuit.

Description

Photovoltaic power generation grid-connected inverter control method based on active damping
Technical Field
The invention belongs to the technical field of power electronics, and relates to a photovoltaic power generation grid-connected inverter control method based on active damping.
Background
Photovoltaic power generation is an important direction of new energy research, and a photovoltaic grid-connected inverter is an important link of a photovoltaic power generation system. The structure of a photovoltaic power generation system is generally formed by combining two parts, namely a photovoltaic array and a power grid connection part.
Frequent starting and stopping of the switching devices in the operation of the inverter can cause the output side of the inverter to have certain content of harmonic waves, and when photovoltaic power generation energy is transmitted through the wires, the harmonic waves can be amplified by equivalent impedance of the wires and stray inductance and capacitance of a system. In order to make the system output effect better, the common L-type, LC-type and LCL-type filters eliminate the harmonic in the photovoltaic power generation system.
According to the analysis of the structure and the characteristics of a common filter, the LC and LCL type filters can inhibit harmonic waves higher than the resonant frequency, have high attenuation response speed and are widely applied to the design of a grid-connected inverter. The LCL type filter has a better decoupling capability than the grid impedance, but needs to consider the resonance spike at the resonance frequency and the current ripple generated at the inductance, which may adversely affect the grid when grid-connected.
The resonance is an important direction in the research of the grid-connected inverter, and according to the reason of the resonance generation, the resonance at the resonance frequency can be restrained by increasing the damping in the system of the inverter, and the damping of the grid-connected inverter mainly comprises two types of passive damping and active damping. Passive damping is the simplest and direct control method and is not limited by the frequency of the used switching device, but the method mainly utilizes series or parallel resistors in each branch of a filter to increase the damping of the system, and the extra power consumption of the system is increased, so that the efficiency of the system is reduced. The active damping mainly utilizes an intelligent control algorithm, can overcome the defect of passivity, does not need to add additional electric elements in the filter, and does not have additional power consumption.
In order to realize active damping control, a method for realizing damping based on capacitance current feedback control is researched and proposed, and a damping mode of capacitance voltage feedback is also proposed. Later researches propose that the split capacitance method is used for converting a third-order system into a first-order system to solve the existing resonance problem, but the split capacitance method is difficult to realize in practical engineering. Common controllers for linear control of grid current include, for example, integral (PI) controllers, Proportional Resonant (PR) controllers, and predictive control, but these controllers have disadvantages such as complexity and poor grid-connected dynamic performance. There is also a need to suppress resonances due to inverter side current harmonics and grid side voltage harmonics near the resonant frequency.
Disclosure of Invention
The invention aims to provide a photovoltaic power generation grid-connected inverter control method based on active damping, and solves the problem that the existing photovoltaic power generation grid-connected inverter control method is difficult to inhibit system resonance peak and makes the grid-connected system have weak anti-interference capability.
The technical scheme adopted by the invention is that the photovoltaic power generation grid-connected inverter control method based on active damping is characterized by comprising the following steps:
step 1, collecting inverter signals, and carrying out Park conversion on the collected inverter signals;
step 2, establishing a Hamilton system mathematical model, namely a PCHD mathematical model, according to the LCL type grid-connected inverter;
step 3, calculating the passive control rate U of the system through the PCHD mathematical model, and controlling the inverter by adopting the passive control rate U of the system to obtain the components U of the system control rate on the d and q axes of the two-phase rotating coordinate systemdAnd Uq；
Step 4, adding Ud，UqTransforming the two-phase static coordinate system to obtain the components U of the system control rate on the alpha and beta axes of the two-phase static coordinate systemαAnd UβWill U isα、UβFiltering the signal in a wave trap to obtain processed alpha and beta axis modulation voltage Uα’、Uβ’；
Step 5, modulating the voltage Uα’、UβThe SVPWM module in the input inverter circuit obtains a duty ratio signal of an inverter circuit switching tube, and the duty ratio signal is input into a drive protection circuit of the LCL type three-phase grid-connected inverter to control the on and off of the inverter circuit switching tube.
Wherein, the inverter signal in the step 1 comprises three-phase voltage U at the inverter sideCa，UCb，UCcAnd three-phase current i1a，i1b，i1cNetwork side three-phase voltage Usa，Usb，UscAnd three-phase current i2a，i2b，i2cAnd the direct current side capacitor voltage U of the grid-connected LCL type three-phase grid-connected inverterdc。
The specific process of step 2 is as follows:
step 2.1, obtaining a mathematical model expression of the three-phase LCL type grid-connected inverter in a two-phase rotating coordinate system according to kirchhoff voltage law KVL and kirchhoff current law KCL, wherein the mathematical model expression is as follows:
Figure BDA0003325259550000041
wherein, UdcIs the DC side capacitor voltage, L, of the inverter grid connection1Is an inductance of the inverter side, L2Is an inductance on the grid side i1d，i1qIs a two-phase rotating coordinate system current obtained by the conversion of three-phase current on the inverter side through Parkcd，UcqIs the voltage of a two-phase rotating coordinate system obtained by the Park conversion of the three-phase voltage at the inverter side, omega is the angular frequency of the power grid, and LgIs the equivalent inductance of the power grid, i2d，i2qIs a two-phase rotating coordinate system current, U, obtained by the conversion of three-phase current on the side of a power grid through Parksd，UsqThe method is characterized in that the voltage of a two-phase rotating coordinate system is obtained by carrying out Park conversion on three-phase voltage on the power grid side, C is a filter capacitor, and R is1、R2Resistances, R, of the inverter side and of the grid side, respectivelygIs the equivalent resistance produced by the inverter output;
step 2.2, according to the characteristics of the mathematical model of the Hamilton system, the formula (1) is converted to obtain the PCHD mathematical model, which is as follows:
Figure BDA0003325259550000042
wherein J (x) is a system internal structure matrix, R (x) is a system dissipation matrix, g (x) is a system internal and external interconnection matrix, x is a system input state variable,
Figure BDA0003325259550000043
represents the derivative of x with respect to time; u is a control input vector, H (x) is a system Hamiltonian, and y is a system output quantity;
wherein the content of the first and second substances,
Figure BDA0003325259550000051
R(x)＝ding{R1 R1 R2+Rg R2+Rg 0 0} (4)
Figure BDA0003325259550000052
Figure BDA0003325259550000053
wherein x is1、x2、x3、x4、x5、x6Representing the system input at 6 different points in time.
The specific process of step 3 is as follows:
step 3.1, obtaining an energy balance equation dH (x)/dt ═ u of PCHD according to the PCHD mathematical modelTy, then the dissipation inequality of the system is found to be:
Figure BDA0003325259550000054
wherein t represents time;
step 3.2, the closed-loop PCHD model of the system is made as follows:
Figure BDA0003325259550000055
wherein, Jd(x)＝Ja(x) + J (x) and Rd(x)＝Ra(x) + R (x) are the new interconnection and dissipation matrices, Ra(x) For damping the injection matrix, Hd(x)＝Ha(x) + H (x) is the total energy storage function,
order to
Figure BDA0003325259550000061
And K (x) satisfies integrability:
Figure BDA0003325259550000062
at the equilibrium point there are:
Figure BDA0003325259550000063
x is a reference value of the system input state variable;
the Lyapunov stability was:
Figure BDA0003325259550000064
such that:
Figure BDA0003325259550000065
in the formula Rd(x)＝Rd(x)T；
And 3.3, performing phase-shift transformation on the formula (12) to obtain a passive control rate of the system, wherein the passive control rate is as follows:
Figure BDA0003325259550000066
control design of inverter according to equation (13), take Ja(x)＝0，Ra(x)＝ding{r1 r2 r3 r4 r5r6Inputting the data after Park transformation in the step 1 into a passive controller as a control object, and enabling x to be x3→x3 *，x4→x4 *And solving for x through PCHD mathematical model1、x2、x5、x6With x3、x4To finally realize x → x*Namely:
Figure BDA0003325259550000071
wherein r isnIs damping coefficient (n is 1, 2, 3, 4, 5, 6);
and 3.4, combining the formula (14) with a system control equation to obtain a switching function component S on two coordinate axes of d and qdAnd SqI.e., system control rate:
Figure BDA0003325259550000072
step 3.5, according to the switching function component SdAnd SqObtaining a direct axis modulation voltage UdQuadrature axis modulated voltage Uq，
Figure BDA0003325259550000073
In the formula of Urefd，UrefqReference voltages are given for the d-axis and the q-axis, respectively.
Step 3.3The data i after the Park transformation in the step 1 is processed1d、i1q、i2d、i2q、Ucd、Ucq、UsdAnd UsqThe input passive controller is taken as a control object, so that x3→x3 *，x4→x4 *。
The invention has the advantages that a Hamilton system-based mathematical model is established by analyzing the LCL type grid-connected inverter and the PCHD system, a system resonance peak is inhibited in a series wave trap mode, a passive control (PBC) theory is used for designing a three-phase LCL type grid-connected inverter controller on the basis of classical control theory, PI and other traditional controllers, a passive controller is designed, and the anti-interference capability of the grid-connected system is improved; in order to improve the output performance of a high frequency band, active damping control based on a wave trap is provided, and based on the improvement, the effective suppression of a system resonance peak is achieved and the anti-interference capability of a grid-connected system is improved.
Drawings
FIG. 1 is a block diagram of a passive controller of a three-phase LCL grid-connected inverter under a weak power grid in the photovoltaic power generation grid-connected inverter control method based on active damping according to the invention;
FIG. 2 is an inversion system designed on the basis of a passive controller in the control method of the photovoltaic power generation grid-connected inverter based on active damping according to the invention;
FIG. 3 is a structural block diagram of an inverter with a wave trap and a passive controller finally added in the control method of the photovoltaic power generation grid-connected inverter based on active damping;
FIG. 4 is a Baud diagram of a wave trap obtained through a transfer function of the wave trap in the control method of the photovoltaic power generation grid-connected inverter based on active damping;
fig. 5 is a bode diagram of a system after a wave trap is added in the control method of the photovoltaic power generation grid-connected inverter based on active damping.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention discloses a photovoltaic power generation grid-connected inverter control method based on active damping, which refers to the steps of fig. 1 and 2 and comprises the following steps:
step 1, collecting three-phase voltage U at inverter sideCa，UCb，UCcAnd three-phase current i1a，i1b，i1cNetwork side three-phase voltage Usa，Usb，UscAnd three-phase current i2a，i2b，i2cAnd the direct current side capacitor voltage U of the grid-connected LCL type three-phase grid-connected inverterdcRespectively carrying out Park conversion on the collected three-phase voltage and three-phase current on the inverter side and the collected three-phase voltage and three-phase current on the network side;
step 2, establishing a Hamilton system mathematical model, namely a PCHD mathematical model, according to the LCL type grid-connected inverter;
the specific process of step 2 is as follows:
step 2.1, obtaining a mathematical model expression of the three-phase LCL type grid-connected inverter in a two-phase rotating coordinate system according to kirchhoff voltage law KVL and kirchhoff current law KCL, wherein the mathematical model expression is as follows:
Figure BDA0003325259550000091
wherein, UdcIs the DC side capacitor voltage, L, of the inverter grid connection1Is an inductance of the inverter side, L2Is an inductance on the grid side i1d，i1qIs a two-phase rotating coordinate system current, U, obtained by Clark conversion of a three-phase current at the inverter sidecd，UcqIs the voltage of a two-phase rotating coordinate system obtained by Clark conversion of the three-phase voltage at the inverter side, omega is the angular frequency of a power grid, and LgIs the equivalent inductance of the power grid, i2d，i2qIs a two-phase rotating coordinate system current, U, obtained by Clark conversion of a three-phase current at the power grid sidesd，UsqThe two-phase rotating coordinate system voltage is obtained by Clark conversion of three-phase voltage at the power grid side, C is a filter capacitor, and R is1、R2Resistances, R, of the inverter side and of the grid side, respectivelygIs the equivalent resistance produced by the inverter output;
step 2.2, according to the characteristics of the mathematical model of the Hamilton system, the formula (1) is converted to obtain the PCHD mathematical model, which is as follows:
Figure BDA0003325259550000101
wherein J (x) is a system internal structure matrix, R (x) is a system dissipation matrix, g (x) is a system internal and external interconnection matrix which indicates the internal and external interconnection conditions of the system, x is a system input state variable,
Figure BDA0003325259550000102
representing the derivative of x to time, u is a control input vector, H (x) is a system Hamiltonian and reflects the energy in an energy storage element of the system, and y is the output quantity of the system;
wherein the content of the first and second substances,
Figure BDA0003325259550000103
R(x)＝ding{R1 R1 R2+Rg R2+R g 0 0} (4)
Figure BDA0003325259550000104
Figure BDA0003325259550000105
wherein x is1、x2、x3、x4、x5、x6Representing the system input quantity of 6 different time points;
step 3, calculating the passive control rate u of the system through the PCHD mathematical model, designing to obtain a passive controller according to the passive control rate u, and inputting the data after Park conversion in the step 1 into the passive controllerIn a source controller, a controller outputs a direct axis modulation voltage UdQuadrature axis modulated voltage Uq；
The specific process of step 3 is as follows:
step 3.1, obtaining an energy balance equation dH (x)/dt ═ u of PCHD according to the PCHD mathematical modelTy, then the dissipation inequality of the system is found to be:
Figure BDA0003325259550000111
wherein t represents time;
step 3.2, setting a control rate to ensure that the closed-loop PCHD model of the system is as follows:
Figure BDA0003325259550000112
wherein, Jd(x)＝Ja(x) + J (x) and Rd(x)＝Ra(x) + R (x) are the new interconnection and dissipation matrices, Ra(x) For damping the injection matrix, Hd(x)＝Ha(x) + H (x) is the total energy storage function;
order to
Figure BDA0003325259550000113
And K (x) satisfies integrability:
Figure BDA0003325259550000114
at the equilibrium point there are:
Figure BDA0003325259550000115
x is a reference value of the system input state variable;
the Lyapunov stability was:
Figure BDA0003325259550000121
obtaining:
Figure BDA0003325259550000122
in the formula Rd(x)＝Rd(x)T；
And 3.3, performing phase-shift transformation on the formula (12) to obtain a passive control rate of the system, wherein the passive control rate is as follows:
Figure BDA0003325259550000123
obtaining a passive controller by controlling and designing the inverter according to the formula (13), and taking Ja(x)＝0，Ra(x)＝ding{r1 r2 r3 r4 r5 r6Inputting the data subjected to Park transformation in the step 1 into a passive controller as a control object (see fig. 3), so that x is3→x3 *，x4→x4 *And solving for x through PCHD mathematical model1、x2、x5、x6With x3、x4To finally realize x → x*Namely:
Figure BDA0003325259550000124
wherein r isnIs damping coefficient (n is 1, 2, 3, 4, 5, 6);
and 3.4, combining the formula (14) with a system control equation to obtain a switching function component S on two coordinate axes of d and q in order to obtain the control rate of the systemdAnd SqI.e., system control rate:
Figure BDA0003325259550000131
step 3.5, according to the switching function component SdAnd SqObtaining a direct axis modulation voltage UdQuadrature axis modulated voltage Uq，
Figure BDA0003325259550000132
In the formula of Urefd，UrefqReference voltages are given for the d-axis and the q-axis, respectively.
Step 4, adding Ud，UqTransforming into a two-phase static coordinate system to obtain components U of the two-phase static coordinate system on alpha and beta axesαAnd UβWill U isα、UβFiltering the signal in a wave trap to obtain processed alpha and beta axis modulation voltage Uα’、Uβ’；
The transfer function of the trap in this embodiment is:
Figure BDA0003325259550000133
xi in the formula (17) is a damping coefficient of the wave trap, ωnFor the trap to reverse the resonance angular frequency, a bode diagram of the trap can be obtained by the transfer function of the trap as shown in fig. 4.
The transfer function of the trap according to equation (17) is known at a frequency of ωnA large reverse gain is produced, and the gain at the other corresponding frequencies is 0. Therefore, the backward peak of the wave trap after being added in the wave trap can counteract the forward peak at the system frequency, so as to achieve the effect of inhibiting the resonance peak and finally output the processed modulation voltage Uα’、Uβ’；
Step 5, modulating the voltage Uα’、UβThe SVPWM module in the input inverter circuit obtains a duty ratio signal of an inverter circuit switching tube, and the duty ratio signal is input into a drive protection circuit of the LCL type three-phase grid-connected inverter to control the on and off of the inverter circuit switching tube.
Fig. 5 is a bode diagram of the LCL filter and the trap under weak power grid, and it is apparent from the bode diagram of the LCL filter and the bode diagram of the trap alone that the LCL filter and the trap have obvious resonance peak suppression effect.

Claims (5)

1. A photovoltaic power generation grid-connected inverter control method based on active damping is characterized by comprising the following steps:
step 1, collecting inverter signals, and carrying out Park conversion on the collected inverter signals;
step 2, establishing a Hamilton system mathematical model, namely a PCHD mathematical model, according to the LCL type grid-connected inverter;
step 3, calculating the passive control rate U of the system through the PCHD mathematical model, and controlling the inverter by adopting the passive control rate U of the system to obtain the components U of the system control rate on the d and q axes of the two-phase rotating coordinate systemdAnd Uq；
Step 4, adding Ud，UqTransforming the two-phase static coordinate system to obtain the components U of the system control rate on the alpha and beta axes of the two-phase static coordinate systemαAnd UβWill U isα、UβFiltering the signal in a wave trap to obtain processed alpha and beta axis modulation voltage Uα’、Uβ’；
Step 5, modulating the voltage Uα’、UβThe SVPWM module in the input inverter circuit obtains a duty ratio signal of an inverter circuit switching tube, and the duty ratio signal is input into a drive protection circuit of the LCL type three-phase grid-connected inverter to control the on and off of the inverter circuit switching tube.
2. The method for controlling the photovoltaic power generation grid-connected inverter based on the active damping as claimed in claim 1, wherein the inverter signal in the step 1 comprises an inverter-side three-phase voltage UCa，UCb，UCcAnd three-phase current i1a，i1b，i1cNetwork side three-phase voltage Usa，Usb，UscAnd three-phase current i2a，i2b，i2cAnd the direct current side capacitor voltage U of the grid-connected LCL type three-phase grid-connected inverterdc。
3. The active damping-based photovoltaic power generation grid-connected inverter control method according to claim 2, wherein the specific process of the step 2 is as follows:
step 2.1, obtaining a mathematical model expression of the three-phase LCL type grid-connected inverter in a two-phase rotating coordinate system according to kirchhoff voltage law KVL and kirchhoff current law KCL, wherein the mathematical model expression is as follows:
Figure FDA0003325259540000021
wherein, UdcIs the DC side capacitor voltage, L, of the inverter grid connection1Is an inductance of the inverter side, L2Is an inductance on the grid side i1d，i1qIs a two-phase rotating coordinate system current obtained by the conversion of three-phase current on the inverter side through Parkcd，UcqIs the voltage of a two-phase rotating coordinate system obtained by the Park conversion of the three-phase voltage at the inverter side, omega is the angular frequency of the power grid, and LgIs the equivalent inductance of the power grid, i2d，i2qIs a two-phase rotating coordinate system current, U, obtained by the conversion of three-phase current on the side of a power grid through Parksd，UsqThe method is characterized in that the voltage of a two-phase rotating coordinate system is obtained by carrying out Park conversion on three-phase voltage on the power grid side, C is a filter capacitor, and R is1、R2Resistances, R, of the inverter side and of the grid side, respectivelygIs the equivalent resistance produced by the inverter output;
step 2.2, according to the characteristics of the mathematical model of the Hamilton system, the formula (1) is converted to obtain the PCHD mathematical model, which is as follows:
Figure FDA0003325259540000031
wherein J (x) is a system internal structure matrix, R (x) is a system dissipation matrix, g (x) isAn internal and external interconnection matrix of the system, x is a system input state variable,
Figure FDA0003325259540000032
represents the derivative of x with respect to time; u is a control input vector, H (x) is a system Hamiltonian, and y is a system output quantity;
wherein the content of the first and second substances,
Figure FDA0003325259540000033
R(x)＝ding{R1 R1 R2+Rg R2+Rg 0 0} (4)
Figure FDA0003325259540000034
Figure FDA0003325259540000035
wherein x is1、x2、x3、x4、x5、x6Representing the system input at 6 different points in time.
4. The active damping-based photovoltaic power generation grid-connected inverter control method according to claim 3, wherein the specific process of the step 3 is as follows:
step 3.1, obtaining an energy balance equation dH (x)/dt ═ u of PCHD according to the PCHD mathematical modelTy, then the dissipation inequality of the system is found to be:
Figure FDA0003325259540000041
wherein t represents time;
step 3.2, the closed-loop PCHD model of the system is made as follows:
Figure FDA0003325259540000042
wherein, Jd(x)＝Ja(x) + J (x) and Rd(x)＝Ra(x) + R (x) are the new interconnection and dissipation matrices, Ra(x) For damping the injection matrix, Hd(x)＝Ha(x) + H (x) is the total energy storage function,
order to
Figure FDA0003325259540000043
And K (x) satisfies integrability:
Figure FDA0003325259540000044
at the equilibrium point there are:
Figure FDA0003325259540000045
x is a reference value of the system input state variable;
the Lyapunov stability was:
Figure FDA0003325259540000046
such that:
Figure FDA0003325259540000047
in the formula Rd(x)＝Rd(x)T；
And 3.3, performing phase-shift transformation on the formula (12) to obtain a passive control rate of the system, wherein the passive control rate is as follows:
Figure FDA0003325259540000051
control design of inverter according to equation (13), take Ja(x)＝0，Ra(x)＝ding{r1r2 r3 r4 r5 r6Inputting the data after Park transformation in the step 1 into a passive controller as a control object, and enabling x to be x3→x3 *，x4→x4 *And solving for x through PCHD mathematical model1、x2、x5、x6With x3、x4To finally realize x → x*Namely:
Figure FDA0003325259540000052
wherein r isnIs damping coefficient (n is 1, 2, 3, 4, 5, 6);
and 3.4, combining the formula (14) with a system control equation to obtain a switching function component S on two coordinate axes of d and qdAnd SqI.e., system control rate:
Figure FDA0003325259540000053
step 3.5, according to the switching function component SdAnd SqObtaining a direct axis modulation voltage UdQuadrature axis modulated voltage Uq，
Figure FDA0003325259540000061
In the formula of Urefd，UrefqReference voltages are given for the d-axis and the q-axis, respectively.
5. A method according to claim 4The control method of the active damping photovoltaic power generation grid-connected inverter is characterized in that in the step 3.3, data i after Park conversion in the step 1 are processed1d、i1q、i2d、i2q、Ucd、Ucq、UsdAnd UsqThe input passive controller is taken as a control object, so that x3→x3 *，x4→x4 *。
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