CN115202201A - Three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference - Google Patents
Three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference Download PDFInfo
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Abstract
The embodiment of the invention provides a three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference, wherein a mathematical model of a photovoltaic grid-connected inverter is established by considering input time lag in the photovoltaic grid-connected inverter; the method comprises the steps of regarding interference caused by model coupling terms, dead zone effects and uncertainty disturbance as lumped interference, mapping the lumped interference to an input end of a system, carrying out reverse compensation on the lumped interference, and establishing a state space equation of the photovoltaic grid-connected inverter; establishing a state space equation of a current controller of the photovoltaic grid-connected inverter system based on a prediction equivalent input interference method, wherein the state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter based on the established state space equation; gains of a full-dimensional state observer and a state feedback predictor in the current controller are obtained and set. The current controller can effectively inhibit negative influences of input time lag, dead zone effect and model coupling terms in the photovoltaic grid-connected inverter system on grid-connected electric energy quality.
Description
Technical Field
The embodiment of the invention relates to the technical field of current control of a new energy grid-connected system, in particular to a three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference.
Background
In order to efficiently utilize new energy such as solar energy, the research of a distributed power generation technology is more and more mature, and China is the country with the highest global photovoltaic installed capacity at present. The grid-connected inverter is used as a core device of a distributed power generation system, and the performance of the grid-connected inverter directly determines the quality of grid-connected electric energy and the stable operation capacity of the system. The grid-connected inverter current control method is designed to improve the output electric energy quality of the photovoltaic grid-connected inverter system, and has great significance for the problems of efficient utilization of renewable energy sources and high-quality electric energy supply.
In an actual power system, in order to prevent a short circuit problem caused by simultaneous conduction of the non-inverting arms of the inverter, it is inevitably necessary to add a dead time to a drive signal of the switching device. However, the dead zone effect may bring low-frequency-dominant harmonics to the output voltage of the inverter, thereby seriously reducing the quality of the grid-connected current, and even affecting the stability of the system. Meanwhile, input time lags such as transmission delays and calculation delays in digital control can degrade controller performance. The equivalent input interference method can be used for equating the influence of uncertain interference on system output to an input channel without prior interference information, so that the equivalent input interference method can better inhibit a dead zone effect. However, input skew in a grid-tied system can severely degrade the performance of the equivalent input disturbance method in terms of given signal following, disturbance rejection, and the like.
Disclosure of Invention
The embodiment of the invention provides a three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference, which are used for solving the technical problem that input time lag and dead zone effect are difficult to inhibit simultaneously in the prior art.
In order to solve the above problem, in a first aspect, an embodiment of the present invention provides a control method for a three-phase photovoltaic grid-connected inverter based on equivalent interference, where the photovoltaic grid-connected inverter includes a full-bridge inverter circuit, an LCL filter, and a current controller, the full-bridge inverter circuit is connected in parallel with a photovoltaic array, an input end of the LCL filter is connected to the full-bridge inverter circuit, and an output end of the LCL filter is connected to a power grid; the method comprises the following steps:
s1, establishing a first state space equation of a photovoltaic grid-connected inverter based on input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to the first state space equation;
s2, establishing a second state space equation of the current controller based on a prediction equivalent input interference method, wherein the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and S3, determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
Preferably, the photovoltaic array and the direct current bus capacitor C bus Connecting in parallel;
the full-bridge inverter circuit comprises a plurality of insulated gate bipolar transistors integrated with freewheeling diodes, the anodes of the freewheeling diodes are connected with the emitting electrodes of the insulated gate bipolar transistors, and the cathodes of the freewheeling diodes are connected with the collecting electrodes of the insulated gate bipolar transistors; the plurality of insulated gate bipolar transistors comprises a first insulated gate bipolar transistor S 1 The first stepTwo insulated gate bipolar transistor S 2 A third insulated gate bipolar transistor S 3 And a fourth insulated gate bipolar transistor S 4 A fifth insulated gate bipolar transistor S 5 And a sixth insulated gate bipolar transistor S 6 (ii) a The first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistor S 4 The first insulated gate bipolar transistor S 1 Collector electrode of (1), fourth insulated gate bipolar transistor S 4 The emitting electrodes of the two-way light-emitting diode are respectively connected with two ends of a direct current bus capacitor; the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 The second insulated gate bipolar transistor S 2 Collector of (2), fifth insulated gate bipolar transistor S 5 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor; the third insulated gate bipolar transistor S 3 And a sixth insulated gate bipolar transistor S 6 The third insulated gate bipolar transistor S 3 Collector electrode of (1), sixth insulated gate bipolar transistor S 6 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor;
the LCL filter comprises three groups of filter circuits, and one ends of the three filter circuits are respectively connected to the first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistor S 4 And the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 The third insulated gate bipolar transistor S 3 And a sixth insulated gate bipolar transistor S 6 To (c) to (d); the other ends of the three filter circuits are respectively connected to a power grid; the filter circuit comprises a first inductor L connected in series 1 A first resistor R 1 A second resistor R 2 And a second inductance L 2 The first resistor R 1 And said second resistance R 2 One end of a filter capacitor C is connected among the three filter circuits, and the other end of the filter capacitor C of the three filter circuits is connected;
the output quantity of the current controller controls driving signals of six insulated bipolar transistors in the full-bridge inverter circuit, so that the output current of the full-bridge inverter circuit is controlled, the output current is filtered by the LCL filter and then is connected to the grid, and the grid-connected current is fed back to the current controller as feedback quantity.
Preferably, the step S1 specifically includes:
the method comprises the steps of determining a space state equation of the photovoltaic grid-connected inverter under a three-phase static coordinate system based on input time lag, converting the space state equation into a space state equation under a rotating coordinate system based on a space coordinate vector conversion method, controlling active components and reactive air quantity of input current of the inverter independently, and taking a coupling term under the rotating coordinate system as a part of lumped interference.
Preferably, in step S1, the first state space equation of the photovoltaic grid-connected inverter is:
wherein t represents a time variable, and h represents an input time lag;
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
a represents a state matrix, B represents an input matrix, C = [0 1 =]Represents the output matrix, L 1 、L 2 C represents an inverter side filter inductor, a network side filter inductor and a filter capacitor respectively; x (t)) And
respectively representing state variables of the first state space equation and corresponding first order differentials; u (t-h) represents an input variable, i 2 (t) represents a grid-connected current, d e (t) represents lumped interference, d d (t) represents a coupling term, d dead (t)、d gds (t) represents the interference due to the dead zone effect and the network voltage distortion, B dead 、B gds Representing the interfering input channel.
Preferably, in step S2, the internal model predictor is respectively:
in the above formula, x S (t) and
representing the state variables of the internal model predictor and their first order differentials, A, respectively S 、B S 、C S The state matrix, input matrix, output matrix, y, of the intra-model predictor, respectively R Representing internal model output quantity, y s (t) represents an internal model prediction quantity;
the full-dimensional state observer is as follows:
in the above formula, the first and second carbon atoms are,
represents a state observed quantity, i 2d And
respectively representing the component of the grid-connected current on the d-axis and the observed quantity, L O Denotes observer gain, u f (t-h) represents the output of the state feedback predictorThe amount of the discharged materials is measured,
representing the output of a full-dimensional state observer;
the state predictor is:
in the above formula, the first and second carbon atoms are,
indicating a state prediction quantity, L P The gain of the state predictor is represented and,
representing a state prediction intermediate quantity;
the interference estimator and the interference predictor are respectively:
in the above formula, B + ＝(B T B) -1 B T ，
In order to provide a lumped interference estimator,
error amount for state prediction, x d (t) and
respectively, the gain of the interference predictor, respectively,
denotes the interference prediction quantity, A d 、B d 、C d Respectively, an interference predictor state matrix, an input matrix, an output matrix, u f (t) is the output quantity of the state feedback controller, and u (t) is the output quantity of the current controller;
the filter is as follows:
F(s)＝1/(Ts+1)
in the above formula, F(s) is a first-order low-pass filter, and T is a filter time constant;
the state feedback controller is as follows:
in the above formula, K R For internal model predictor feedback gain, K P The gain is fed back to the state predictor.
Preferably, after the second state space equation of the current controller is established in step S2, setting a stability determination condition of the current controller further includes:
(A-L O c) All feature roots of (a) have a negative real part;
all solutions of the eigenequation for H(s) have a negative real part; wherein H(s) = C d (sI-A d ) -1 B d ；
||GFH|| ∞ ＜1
[K R ,K P ],K S And L P So that
All feature roots of (a) have a negative real part;
wherein the content of the first and second substances,
preferably, the step S2 specifically includes:
setting the time constant 1/T > 10 omega of the filter r Wherein ω is r Is the grid frequency;
setting the A in the interference predictor in the step S2 based on a first state space equation of the photovoltaic grid-connected inverter d 、B d 、C d A value of (d);
establishing a dual model of the first state space equation:
determining a positive definite matrix based on an optimal adjustment method
Positive real number
And rho → ∞ to solve the following quadratic optimal performance index equation to obtain the gain of the state observer:
in the above formula, the first and second carbon atoms are,
the solution of (2);
solving for
Obtaining a gain of the state observer;
authentication
And whether the stability judging conditions are simultaneously satisfied, otherwise, returning to the step S2.
In a second aspect, an embodiment of the present invention provides a three-phase photovoltaic grid-connected inverter control system based on equivalent interference, where the photovoltaic grid-connected inverter includes a full-bridge inverter circuit, an LCL filter, and a current controller, the full-bridge inverter circuit is connected in parallel with a photovoltaic array, an input end of the LCL filter is connected to the full-bridge inverter circuit, and an output end of the LCL filter is incorporated into a power grid; the system comprises:
the photovoltaic grid-connected inverter analysis module is used for establishing a first state space equation of the photovoltaic grid-connected inverter based on the input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to the input end of the first state space equation;
the current controller design module is used for establishing a second state space equation of the current controller based on a prediction equivalent input interference method, and the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and the current control module is used for determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
In a third aspect, an embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the steps of the equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to the embodiment of the first aspect of the present invention.
In a fourth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the equivalent interference based three-phase photovoltaic grid-connected inverter control method according to the embodiment of the first aspect of the present invention.
According to the three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference, input time lag in the photovoltaic grid-connected inverter is considered, and a mathematical model of the photovoltaic grid-connected inverter is established; the method comprises the steps of regarding interference caused by model coupling terms, dead zone effects and uncertainty disturbance as lumped interference, mapping the lumped interference to an input end of a system, carrying out reverse compensation on the lumped interference, and establishing a state space equation of the photovoltaic grid-connected inverter; establishing a state space equation of a current controller of a photovoltaic grid-connected inverter system based on a prediction equivalent input interference method, wherein the state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter based on the established state space equation; gains of a full-dimensional state observer and a state feedback predictor in the current controller are obtained and set. The invention has the beneficial effects that: the designed current controller can effectively inhibit negative influences of input time lag, dead zone effect and model coupling terms in the photovoltaic grid-connected inverter system on grid-connected electric energy quality.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a flow chart of a three-phase photovoltaic grid-connected inverter control method based on equivalent interference according to an embodiment of the invention;
fig. 2 is a diagram of a structure of a photovoltaic grid-connected inverter according to an embodiment of the present invention;
fig. 3 is a block diagram of a current controller of a photovoltaic grid-connected inverter according to an embodiment of the present invention;
FIG. 4 is a block diagram of a split design of a current controller according to an embodiment of the present invention;
fig. 5 is a diagram of the grid-connected current control effect of a three-phase photovoltaic grid-connected inverter with input time lag according to the embodiment of the invention;
FIG. 6 is a grid-connected current harmonic frequency spectrum diagram of a three-phase photovoltaic grid-connected inverter with hysteresis at input according to the embodiment of the invention;
FIG. 7 is a graph comparing grid-connected current harmonic spectra of a three-phase grid-connected photovoltaic inverter system according to an embodiment of the present invention, which includes an input time lag and is used in combination with other current control methods;
fig. 8 is a graph comparing the grid-connected current total harmonic distortion of the three-phase photovoltaic grid-connected inverter system according to the embodiment of the present invention with other current control methods under the dead zone effect including input time lag and change;
fig. 9 is a schematic physical structure diagram according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the embodiment of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone.
The terms "first", "second" in the embodiments of the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying any indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "comprise" and "have", as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a system, product or apparatus that comprises a list of elements or components is not limited to only those elements or components but may alternatively include other elements or components not expressly listed or inherent to such product or apparatus. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
In an actual power system, in order to prevent a short circuit problem caused by simultaneous conduction of the non-inverting arms of the inverter, it is inevitably necessary to add a dead time to a drive signal of the switching device. However, the dead zone effect may bring low-frequency-dominant harmonics to the output voltage of the inverter, thereby seriously reducing the quality of the grid-connected current, and even affecting the stability of the system. Meanwhile, input time lags such as transmission delays and calculation delays in digital control can degrade controller performance. The equivalent input interference method can equate the influence of uncertain interference on system output to an input channel, and does not need prior information of interference, so the equivalent input interference method can better inhibit dead zone effect. However, input skew in a grid-tied system can severely degrade the performance of the equivalent input disturbance method in terms of given signal following, disturbance rejection, and the like.
Therefore, the embodiment of the invention provides a three-phase photovoltaic grid-connected inverter control method based on equivalent interference, the photovoltaic grid-connected inverter comprises a full-bridge inverter circuit, an LCL filter and a current controller, the full-bridge inverter circuit is connected with a photovoltaic array in parallel, the input end of the LCL filter is connected with the full-bridge inverter circuit, and the output end of the LCL filter is connected with a power grid; the method comprises the following steps:
s1, establishing a first state space equation of a photovoltaic grid-connected inverter based on input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to an input end of the first state space equation;
as shown in fig. 2, which is a voltage source type three-phase pv grid-connected inverter according to an embodiment of the present invention, the pv array and the dc bus capacitor C bus Parallel connection;
the full-bridge inverter circuit comprises a plurality of insulated gate bipolar transistors integrated with freewheeling diodes, the anodes of the freewheeling diodes are connected with the emitting electrodes of the insulated gate bipolar transistors, and the cathodes of the freewheeling diodes are connected with the collecting electrodes of the insulated gate bipolar transistors; the plurality of insulated gate bipolar transistors comprises a first insulated gate bipolar transistor S 1 A second insulated gate bipolar transistor S 2 A third insulated gate bipolar transistor S 3 And a fourth insulated gate bipolar transistor S 4 A fifth insulated gate bipolar transistor S 5 And a sixth insulated gate bipolar transistor S 6 (ii) a The first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistor S 4 The first insulated gate bipolar transistor S 1 Collector electrode of (1), fourth insulated gate bipolar transistor S 4 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor; the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 The second insulated gate bipolar transistor S 2 Collector electrode of (1), fifth insulated gate bipolar transistor (S) 5 Is transmitted byThe poles are respectively connected with two ends of a direct current bus capacitor; the third IGBT S 3 And a sixth insulated gate bipolar transistor S 6 The third insulated gate bipolar transistor S 3 Collector electrode of (1), sixth insulated gate bipolar transistor S 6 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor;
the LCL filter comprises three groups of filter circuits, and one ends of the three filter circuits are respectively connected to the first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistor S 4 And the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 The third insulated gate bipolar transistor S 3 And a sixth insulated gate bipolar transistor S 6 To (c) to (d); the other ends of the three filter circuits are respectively connected to a power grid; the filter circuit comprises a first inductor L connected in series 1 A first resistor R 1 A second resistor R 2 And a second inductance L 2 The first resistor R 1 And said second resistance R 2 One end of a filter capacitor C is connected between the three filter circuits, and the other end of the filter capacitor C of the three filter circuits is connected.
The output quantity of the current controller controls driving signals of six insulated bipolar transistors in the full-bridge inverter circuit, so that the output current of the full-bridge inverter circuit is controlled, the output current is filtered by the LCL filter and then is connected to the grid, and the grid-connected current is fed back to the current controller as feedback quantity.
In this embodiment, an input time lag is considered to establish a space state equation of the photovoltaic grid-connected inverter in a three-phase stationary coordinate system, then a model is converted into a space state equation in a synchronous rotating coordinate system through a space coordinate vector transformation technology, so that an active component and a reactive component of an output current of the inverter can be controlled independently, finally, a model coupling term in the synchronous rotating coordinate system is also regarded as a part of lumped interference in step S1, interference caused by the model coupling term, a dead zone effect and uncertainty disturbance is regarded as lumped interference and is mapped to an input end of a system, the lumped interference is subjected to reverse compensation, and a state space equation of the photovoltaic grid-connected inverter is established:
wherein t represents a time variable and h represents an input time lag;
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
a represents a state matrix, B represents an input matrix, C = [0 1 =]Represents the output matrix, L 1 、L 2 C represents a filter inductor at the side of the inverter, a filter inductor at the side of the network and a filter capacitor respectively; x (t) and
respectively representing state variables of the first state space equation and corresponding first order differentials; u (t-h) represents an input variable, i 2 (t) represents a grid-connected current, d e (t) represents lumped interference, d d (t) represents a coupling term, d dead (t)、d gds (t) represents the interference due to the dead zone effect and the network voltage distortion, B dead 、B gds Representing the interfering input channel.
S2, establishing a second state space equation of the current controller based on a prediction equivalent input interference method, wherein the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter as shown in FIG. 3; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
in step S2, the internal model predictors are respectively:
in the above formula, x S (t) and
respectively representing the state variables of the internal model predictor and their first order differentials, A S 、B S 、C S Respectively, the state matrix, input matrix, output matrix, y of the internal model predictor R Representing internal model output quantity, y s (t) represents an internal model prediction quantity;
the full-dimensional state observer is as follows:
in the above formula, the first and second carbon atoms are,
represents a state observed quantity, i 2d And
respectively represents the grid-connected currentComponent on d-axis and its observed quantity, L O Representing observer gain, u f (t-h) represents the state feedback predictor output,
representing a full-dimensional state observer output quantity;
the state predictor is:
in the above-mentioned formula, the compound has the following structure,
indicating a state prediction quantity, L P The gain of the state predictor is represented,
representing a state prediction intermediate quantity;
the interference estimator and the interference predictor are respectively:
in the above formula, B + ＝(B T B) -1 B T ，
In order to provide a lumped interference estimator,
error amount for state prediction, x d (t) and
respectively, the gain of the interference predictor, respectively,
denotes the interference prediction quantity, A d 、B d 、C d Respectively an interference predictor state matrix, an input matrix, an output matrix u f (t) is the output quantity of the state feedback controller, and u (t) is the output quantity of the current controller;
the filter is as follows:
F(s)＝1/(Ts+1)
in the above formula, F(s) is a first-order low-pass filter, and T is a filter time constant;
the state feedback controller is as follows:
in the above formula, K R Feedback gain, K, for the internal model predictor P The gain is fed back for the state predictor.
In the step S2, fig. 4 is equivalent to the case where two subsystems in fig. 5 are connected in series, so that the whole control system stability is equivalent to the case where the subsystem 1 and the subsystem 2 are simultaneously stable. After the second state space equation of the current controller is established, setting a stability determination condition of the current controller, which specifically includes:
(A-L O c) All feature roots of (a) have a negative real part;
all solutions of the eigenequation for H(s) have a negative real part; wherein H(s) = C d (sI-A d ) -1 B d ；
||GFH|| ∞ ＜1
[K R ,K P ],K S And L P So that
All feature roots of (a) have a negative real part;
wherein the content of the first and second substances,
the step S2 specifically includes:
setting the time constant 1/T > 10 omega of the filter r Wherein ω is r Is the grid frequency;
setting A in the interference predictor in the step S2 based on a first state space equation of the photovoltaic grid-connected inverter d 、B d 、C d A value of (d);
establishing a dual model of the first state space equation:
determining a positive definite matrix based on an optimal adjustment method
Positive real number
And rho → ∞ to solve the following quadratic form optimal performance index equation to obtain the gain of the state observer:
in the above-mentioned formula, the compound has the following structure,
is composed of
The solution of (2);
solving for
Obtaining a gain of the state observer;
authentication
And whether the stability judging conditions are simultaneously satisfied, otherwise, returning to the step S2.
And S3, determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on the grid-connected power quality.
The invention will be further illustrated by the following specific examples: in the specific embodiment of the invention, a three-phase LCL type photovoltaic grid-connected inverter system is taken as an example to verify the effectiveness of the proposed three-phase photovoltaic grid-connected inverter current control method based on the predicted equivalent input interference. The method can effectively inhibit the negative influence of input time lag, dead zone effect and model coupling term on the grid-connected current quality, and specifically comprises the following steps:
(1) And (3) building a three-phase LCL type photovoltaic grid-connected inverter system simulation model on the MATLAB/SIMULINK platform according to the figure 1 and the figure 3. The illumination intensity of the photovoltaic array is 1000W/m < 2 >, the temperature is 25 ℃, and the maximum output power is 5.623kW. And all the switching tubes of the inverter system adopt IGBT full-control devices. Table 1 shows parameters of the three-phase LCL-type photovoltaic grid-connected inverter system.
TABLE 1 three-phase LCL type grid-connected PV inverter system parameters
(2) Solving the parameters of the current controller according to the step S3, and determining the stability criterion according to the stability criterion given in the step S3
The control system is known to be stable.
(3) The performance of the current control method of the photovoltaic grid-connected inverter provided by the embodiment under three conditions that the system has input time lag, simultaneously has input time lag and dead zone effect, and simultaneously has input time lag and changed dead zone effect is respectively as follows:
1) An input time lag h =1.5 sampling times is set in a photovoltaic grid-connected inverter system, and under the action of a grid-connected current controller based on predicted equivalent input interference, an effect graph of grid-connected current and a harmonic frequency spectrogram of the grid-connected current are respectively shown in fig. 5 and fig. 6. As can be seen from the simulation result diagram, the three-phase amplitudes of the grid-connected current are the same, which shows that the method has good model decoupling capability. The steady-state three-phase grid-connected current waveform has higher sine wave degree, the total current distortion (THD) value is only 0.49 percent and is far lower than the IEEE standard, and the method is proved to be capable of better inhibiting the negative influence caused by input time lag.
2) The invention relates to a method for setting input time lag h =1.5 sampling time in a photovoltaic grid-connected inverter system, which is based on the proportion
A comparison graph of grid-connected current harmonic frequency spectrums of the three-phase photovoltaic grid-connected inverter system based on other current control methods such as integral (PI) control, proportional integral and repetitive control combined (PI-RC) control method, equivalent input interference (EID) method and the like is shown in fig. 7. The method has the advantages that the best harmonic suppression effect is achieved in each order of harmonic waves, and input time lag and interference caused by model coupling terms can be suppressed to the maximum extent.
3) Simultaneously setting input time lag h =1.5 sampling times in a photovoltaic grid-connected inverter system, and simultaneously setting
The comparison graph of the total harmonic distortion of the grid-connected current of the three-phase photovoltaic grid-connected inverter system with other current control methods is shown in fig. 8 according to the dead time varying within the range of 2ms to 6 ms. Simulation results show that the THD value is always less than 2% along with the increase of dead time under the action of the current control method provided by the invention.
The embodiment of the invention also provides a three-phase photovoltaic grid-connected inverter control system based on equivalent interference, and the three-phase photovoltaic grid-connected inverter control method based on equivalent interference in the above embodiments is characterized in that the photovoltaic grid-connected inverter comprises a full-bridge inverter circuit, an LCL filter and a current controller, the full-bridge inverter circuit is connected in parallel with a photovoltaic array, the input end of the LCL filter is connected with the full-bridge inverter circuit, and the output end of the LCL filter is connected with a power grid; the system comprises:
the photovoltaic grid-connected inverter analysis module is used for establishing a first state space equation of the photovoltaic grid-connected inverter based on the input time lag of the photovoltaic grid-connected inverter, taking interference caused by coupling terms, dead zone effects and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to the first state space equation;
the current controller design module is used for establishing a second state space equation of the current controller based on a prediction equivalent input interference method, and the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and the current control module is used for determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
Based on the same concept, an embodiment of the present invention further provides an entity structure schematic diagram, as shown in fig. 9, the server may include: a processor (processor) 810, a communication Interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication Interface 820 and the memory 830 communicate with each other via the communication bus 840. The processor 810 may invoke logic instructions in the memory 830 to perform the steps of the equivalent disturbance based three-phase pv grid-connected inverter control method as described in the various embodiments above. Examples include:
s1, establishing a first state space equation of a photovoltaic grid-connected inverter based on input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to an input end of the first state space equation;
s2, establishing a second state space equation of the current controller based on a prediction equivalent input interference method, wherein the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and S3, determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
In addition, the logic instructions in the memory 830 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Based on the same concept, embodiments of the present invention further provide a non-transitory computer-readable storage medium, where a computer program is stored, where the computer program includes at least one code, and the at least one code is executable by a main control device to control the main control device to implement the steps of the equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to the embodiments. Examples include:
s1, establishing a first state space equation of a photovoltaic grid-connected inverter based on input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to an input end of the first state space equation;
s2, establishing a second state space equation of the current controller based on a prediction equivalent input interference method, wherein the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and S3, determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
Based on the same technical concept, the embodiment of the present application further provides a computer program, which is used to implement the above method embodiment when the computer program is executed by the main control device.
The program may be stored in whole or in part on a storage medium packaged with the processor, or in part or in whole on a memory not packaged with the processor.
Based on the same technical concept, the embodiment of the present application further provides a processor, and the processor is configured to implement the above method embodiment. The processor may be a chip.
In summary, according to the three-phase photovoltaic grid-connected inverter control method and system based on equivalent interference provided by the embodiment of the invention, the input time lag in the photovoltaic grid-connected inverter is considered, and a mathematical model of the photovoltaic grid-connected inverter is established; the method comprises the steps of regarding interference caused by model coupling terms, dead zone effects and uncertainty disturbance as lumped interference, mapping the lumped interference to an input end of a system, carrying out reverse compensation on the lumped interference, and establishing a state space equation of the photovoltaic grid-connected inverter; establishing a state space equation of a current controller of the photovoltaic grid-connected inverter system based on a prediction equivalent input interference method, wherein the state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter based on the established state space equation; gains of a full-dimensional state observer and a state feedback predictor in the current controller are obtained and set. The invention has the beneficial effects that: the designed current controller can effectively inhibit negative influences of input time lag, dead zone effect and model coupling terms in the photovoltaic grid-connected inverter system on grid-connected electric energy quality.
The embodiments of the present invention can be arbitrarily combined to achieve different technical effects.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, it may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions described in accordance with the present application are generated, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, digital subscriber line) or wirelessly (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk), among others.
One of ordinary skill in the art will appreciate that all or part of the processes in the methods of the above embodiments may be implemented by hardware related to instructions of a computer program, which may be stored in a computer-readable storage medium, and when executed, may include the processes of the above method embodiments. And the aforementioned storage medium includes: various media capable of storing program codes, such as ROM or RAM, magnetic or optical disks, etc.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The three-phase photovoltaic grid-connected inverter control method based on equivalent interference is characterized in that the photovoltaic grid-connected inverter comprises a full-bridge inverter circuit, an LCL filter and a current controller, the full-bridge inverter circuit is connected with a photovoltaic array in parallel, the input end of the LCL filter is connected with the full-bridge inverter circuit, and the output end of the LCL filter is connected into a power grid; the method comprises the following steps:
s1, establishing a first state space equation of a photovoltaic grid-connected inverter based on input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to an input end of the first state space equation;
s2, establishing a second state space equation of the current controller based on a prediction equivalent input interference method, wherein the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and S3, determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on grid-connected electric energy quality.
2. The three-phase photovoltaic grid-connected inverter control method based on equivalent interference according to claim 1, wherein the photovoltaic array and a direct-current bus capacitor C bus Parallel connection;
the full-bridge inverter circuit comprises a plurality of insulated gate bipolar transistors integrated with freewheeling diodes, the anodes of the freewheeling diodes are connected with the emitting electrodes of the insulated gate bipolar transistors, and the cathodes of the freewheeling diodes are connected with the collecting electrodes of the insulated gate bipolar transistors; the plurality of insulated gate bipolar transistors includes a first insulated gate bipolar transistor S 1 A second IGBT S 2 A third insulated gate bipolar transistor S 3 And a fourth insulated gate bipolar transistor S 4 And a fifth insulated gate bipolar transistor S 5 And a sixth insulated gate bipolar transistor S 6 (ii) a The first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistor S 4 The first insulated gate bipolar transistor S 1 Collector electrode of (1), fourth insulated gate bipolar transistor S 4 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor; the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 The second insulated gate bipolar transistor S 2 Collector electrode of (1), fifth insulated gate bipolar transistor (S) 5 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor; the third insulated gate bipolar transistor S 3 And a sixth insulated gate bipolar transistor S 6 The third insulated gate bipolar transistor S 3 Collector electrode of (1), sixth insulated gate bipolar transistor S 6 The emitting electrodes of the two-way switch are respectively connected with two ends of a direct current bus capacitor;
the LCL filter comprises three groups of filter circuits, and one ends of the three filter circuits are respectively connected to the first insulated gate bipolar transistor S 1 And a fourth insulated gate bipolar transistorS 4 And the second insulated gate bipolar transistor S 2 And a fifth insulated gate bipolar transistor S 5 And the third insulated gate bipolar transistor S 3 And a sixth insulated gate bipolar transistor S 6 In the middle of; the other ends of the three filter circuits are respectively connected to a power grid; the filter circuit comprises a first inductor L connected in series 1 A first resistor R 1 A second resistor R 2 And a second inductance L 2 The first resistor R 1 And said second resistance R 2 One end of a filter capacitor C is connected among the three filter circuits, and the other end of the filter capacitor C of the three filter circuits is connected;
the output quantity of the current controller controls driving signals of six insulated bipolar transistors in the full-bridge inverter circuit, so that the output current of the full-bridge inverter circuit is controlled, the output current is filtered by the LCL filter and then is connected to the grid, and the grid-connected current is fed back to the current controller as feedback quantity.
3. The equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to claim 2, wherein the step S1 specifically comprises:
the method comprises the steps of determining a space state equation of the photovoltaic grid-connected inverter under a three-phase static coordinate system based on input time lag, converting the space state equation into a space state equation under a rotating coordinate system based on a space coordinate vector conversion method, controlling active components and reactive air quantity of input current of the inverter independently, and taking a coupling term under the rotating coordinate system as a part of lumped interference.
4. The equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to claim 2, wherein in the step S1, the first state space equation of the photovoltaic grid-connected inverter is:
wherein t represents a time variable and h represents an input time lag;
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
d e (t)＝B -1 d d (t)+B -1 B dead d dead (t)+B -1 B gds d gds (t)
a represents a state matrix, B represents an input matrix, C = [0 1 =]Represents the output matrix, L 1 、L 2 C represents a filter inductor at the side of the inverter, a filter inductor at the side of the network and a filter capacitor respectively; x (t) and
respectively representing state variables of the first state space equation and corresponding first order differentials; u (t-h) represents an input variable, i 2 (t) represents a grid-connected current, d e (t) represents lumped interference, d d (t) represents a coupling term, d dead (t)、d gds (t) represents the interference due to the dead zone effect and the network voltage distortion, B dead 、B gds Representing the interfering input channel.
5. The equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to claim 4, wherein in the step S2, the internal model predictors are respectively:
in the above formula, the first and second carbon atoms are,x S (t) and
respectively representing the state variables of the internal model predictor and their first order differentials, A S 、B S 、C S Respectively, the state matrix, input matrix, output matrix, y of the internal model predictor R Representing internal model output quantity, y s (t) represents an internal model prediction quantity;
the full-dimensional state observer is as follows:
in the above formula, the first and second carbon atoms are,
represents a state observed quantity, i 2d And
respectively representing the component of the grid-connected current on the d axis and the observed quantity, L O Representing observer gain, u f (t-h) represents the output of the state feedback predictor,
representing the output of a full-dimensional state observer;
the state predictor is:
in the above formula, the first and second carbon atoms are,
denotes a state prediction quantity, L P The gain of the state predictor is represented,
representing a state prediction intermediate quantity;
the interference estimator and the interference predictor are respectively:
in the above formula, B + ＝(B T B) -1 B T ，
In order to provide a lumped interference estimator,
error amount for state prediction, x d (t) and
respectively, the gain of the interference predictor, respectively,
represents the interference prediction quantity, A d 、B d 、C d Respectively an interference predictor state matrix, an input matrix, an output matrix u f (t) is the output quantity of the state feedback controller, and u (t) is the output quantity of the current controller;
the filter is as follows:
F(s)＝1/(Ts+1)
in the above formula, F(s) is a first-order low-pass filter, and T is a filter time constant;
the state feedback controller is as follows:
in the above formula, K R For internal model predictor feedback gain, K P The gain is fed back to the state predictor.
6. The equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to claim 5, wherein in the step S2, after establishing the second state space equation of the current controller, further setting a stability determination condition of the current controller, specifically comprising:
(A-L O c) All feature roots of (a) have a negative real part;
all solutions of the eigenequation for H(s) have a negative real part; wherein H(s) = C d (sI-A d ) -1 B d ；
||GFH|| ∞ ＜1
[K R ,K P ],K S And L P So that
All feature roots of (a) have a negative real part;
wherein the content of the first and second substances,
7. the equivalent interference-based three-phase photovoltaic grid-connected inverter control method according to claim 6, wherein the step S2 specifically comprises:
setting the time constant 1/T > 10 omega of the filter r Wherein ω is r Is the grid frequency;
setting the A in the interference predictor in the step S2 based on a first state space equation of the photovoltaic grid-connected inverter d 、B d 、C d A value of (d);
establishing a dual model of the first state space equation:
determining a positive definite matrix based on an optimal adjustment method
Positive real number
And rho → ∞ to solve the following quadratic optimal performance index equation to obtain the gain of the state observer:
in the above formula, the first and second carbon atoms are,
is composed of
The solution of (2);
solving for
Obtaining the gain of the state observer;
authentication
And whether the stability judging conditions are simultaneously satisfied, otherwise, returning to the step S2.
8. A three-phase photovoltaic grid-connected inverter control system based on equivalent interference comprises a full-bridge inverter circuit, an LCL filter and a current controller, wherein the full-bridge inverter circuit is connected with a photovoltaic array in parallel, the input end of the LCL filter is connected with the full-bridge inverter circuit, and the output end of the LCL filter is connected with a power grid; characterized in that the system comprises:
the photovoltaic grid-connected inverter analysis module is used for establishing a first state space equation of the photovoltaic grid-connected inverter based on the input time lag of the photovoltaic grid-connected inverter, taking interference caused by a coupling term, a dead zone effect and uncertainty disturbance in the first state space equation as lumped interference, and feeding the lumped interference back to the input end of the first state space equation;
the current controller design module is used for establishing a second state space equation of the current controller based on a prediction equivalent input interference method, and the second state space equation comprises an internal model predictor, a full-dimensional state observer, a state feedback predictor, an interference predictor and a filter; the internal model predictor is used for tracking a given signal value of the current controller, the full-dimensional state observer is used for observing the state of a first state space equation, the state feedback predictor is used for superposing the output quantity of the internal model predictor and the state prediction quantity of the full-dimensional state observer and feeding back the output quantity to the input end of the first state space equation, the interference predictor is used for predicting the lumped interference in the step S1, high-frequency noise is filtered by the filter and then fed back to the input end of the first state space equation in a negative feedback mode, and the superposed quantity of the output quantity of the state feedback predictor and the output quantity of the state feedback predictor are used as the control quantity of the first state space equation;
and the current control module is used for determining gain values of the full-dimensional state observer and the state feedback predictor based on the first state space equation and the second state space equation so as to inhibit the influence of input time lag, dead zone effect and coupling terms in the photovoltaic grid-connected inverter on the grid-connected power quality.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program implements the steps of the equivalent interference based three-phase photovoltaic grid-connected inverter control method according to any one of claims 1 to 7.
10. A non-transitory computer readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the equivalent disturbance based three-phase pv grid inverter control method according to any of claims 1 to 7.
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| US20080255814A1 (en) * | 2007-04-13 | 2008-10-16 | Tien-Li Chia | Apparatus and method for model-based control |
| CN111614119A (en) * | 2020-05-22 | 2020-09-01 | 中国地质大学（武汉） | Inverter power control method based on equivalent input interference |
| CN113671833A (en) * | 2021-08-22 | 2021-11-19 | 北京工业大学 | Coordination design method and system for uncertain repetitive control system |
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| US20080255814A1 (en) * | 2007-04-13 | 2008-10-16 | Tien-Li Chia | Apparatus and method for model-based control |
| CN111614119A (en) * | 2020-05-22 | 2020-09-01 | 中国地质大学（武汉） | Inverter power control method based on equivalent input interference |
| CN113671833A (en) * | 2021-08-22 | 2021-11-19 | 北京工业大学 | Coordination design method and system for uncertain repetitive control system |
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| FANG LIU等: "Equivalent Input Disturbance-Based Control Design for Three Phase Dual-Stage Grid-Tied Photovoltaic System Considering Dead Time Effect", 《FRONTIERS IN ENERGY RESEARCH》, 17 December 2021 (2021-12-17) * |
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