Photovoltaic inverter control method based on maximum power point tracking and related device

Abstract

The invention discloses a photovoltaic inverter control method based on maximum power point tracking and a related device, and the method comprises the steps: enabling a photovoltaic inverter to detect the input power inputted by a plurality of photovoltaic cells in a photovoltaic power generation field, and carrying out the starting control of the photovoltaic inverter based on the input power; performing maximum power point tracking processing on the total generated power; calling an inversion unit to perform inversion operation processing on the received input direct current on the basis of tracking the maximum total generation power to obtain alternating current data to be output formed by inversion; carrying out harmonic and inter-harmonic detection processing on the alternating current data to be output; and carrying out filtering processing on the alternating current data to be output based on each harmonic signal and each inter-harmonic signal, and inputting the filtered alternating current data to be output into the power distribution network based on grid-connected connection. In the embodiment of the invention, the power generation efficiency of the photovoltaic power generation field can be effectively improved by tracking the maximum total power generation power, and the oscillation of the power distribution network can be reduced through targeted filtering.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a photovoltaic inverter control method based on maximum power point tracking and related devices. Background Art

[0002] Photovoltaic grid-connected power generation is an important direction of solar energy application and the main way for solar energy to transition from supplementary energy to alternative energy. Among them, the inverter is an important core component in the photovoltaic grid-connected power generation system. It converts the DC power output by the solar cell module into AC power. The quality of its performance directly determines the level of the grid-connected photovoltaic power generation system.

[0003] There are two main aspects of the indicators of photovoltaic grid-connected inverters: high performance indicators, such as conversion efficiency, MPPT (maximum power point tracking) accuracy and grid-connected current harmonics and other power quality indicators, which meet the power quality requirements of the State Grid; complete protection functions, such as AC over-voltage and under-voltage, AC over-frequency and under-frequency, DC over-voltage, over-current, overheating and other protection functions. The inverter should be able to detect the above faults within the specified time and be able to automatically protect. At the same time, the inverter should also have an automatic recovery function, that is, it can automatically resume operation after the fault condition disappears. It is also necessary to solve how to further improve the MPPT accuracy, thereby improving the power generation efficiency of the photovoltaic power plant, and how to further perform precise filtering to ensure the stable operation of the grid-connected distribution network. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art. The present invention provides a photovoltaic inverter control method and related devices based on maximum power point tracking. By tracking the maximum total power generation, the power generation efficiency of the photovoltaic power field can be effectively improved, and the oscillation of the distribution network can be reduced through targeted filtering.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a photovoltaic inverter control method based on maximum power point tracking, which is applied to a photovoltaic inverter, wherein one end of the photovoltaic inverter is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a distribution network; the method comprises:

[0006] The photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power;

[0007] The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain the tracked maximum total power generation power;

[0008] The photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtains the alternating current data to be output formed by the inversion;

[0009] The photovoltaic inverter performs harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal;

[0010] The photovoltaic inverter performs filtering processing on the AC power data to be output based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on the grid connection.

[0011] Optionally, the photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power, including:

[0012] When the photovoltaic inverter detects the input power input by a plurality of photovoltaic cells in the photovoltaic power generation field, it extracts the input voltage data corresponding to the input power;

[0013] The input voltage data is compared with the minimum starting voltage of the photovoltaic inverter, and when the input voltage data is greater than or equal to the minimum starting voltage, the photovoltaic inverter is started and controlled.

[0014] Optionally, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain the tracked maximum total power generation power, including:

[0015] The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on the PV characteristic curve formed by the photovoltaic power field to obtain the tracked maximum total power generation power.

[0016] Optionally, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on a PV characteristic curve formed by the photovoltaic power field to obtain the maximum total power generation power, including:

[0017] Three points a, b, and c are extracted from left to right near the peak point of the PV characteristic curve formed by the photovoltaic power generation field, and the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ;

[0018] The voltage U at point bb As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step;

[0019] Get the power P corresponding to points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <P c ;P a <P b ,P c <P b ;P c <P b <P a ;

[0020] After obtaining the position relationship, a power comparison flag Tag is set, the initial value of the Tag is 0, and the position of point b is adjusted according to the position relationship using the Tag in each judgment cycle. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P b =P max When , the maximum total power generation is obtained.

[0021] Optionally, the adjusting the position of b by using a Tag according to the position relationship in each judgment cycle includes:

[0022] In the position relationship P a <P b <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of points a, b, and c;

[0023] In the position relationship Pa <P b ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of points a, b, and c;

[0024] In the position relationship P c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated U a Equal to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

[0025] Optionally, the photovoltaic inverter calls an inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation to obtain the alternating current data to be output formed by the inversion, including:

[0026] The tracked maximum total power generation is used as the actual input power of the photovoltaic inverter, and the inverter unit is called to perform an inversion operation on the input direct current corresponding to the actual input power to obtain the alternating current data to be output formed by the inversion.

[0027] Optionally, the photovoltaic inverter filters the to-be-output AC power data based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on a grid-connected connection, including:

[0028] Based on the harmonic signals and the interharmonic signals, parameter configuration processing is performed on the filter unit of the photovoltaic inverter to form a configured filter unit, wherein the filter unit is composed of an AC filter, an AC relay, and an AC electromagnetic interference filter in sequence;

[0029] The AC power data to be output is filtered by the configured filtering unit to obtain filtered AC power data to be output;

[0030] The filtered alternating current data to be output is input into the power distribution network based on the grid connection.

[0031] In addition, an embodiment of the present invention further provides a photovoltaic inverter control device based on maximum power point tracking, which is applied to a photovoltaic inverter, wherein one end of the photovoltaic inverter is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a distribution network; the device comprises:

[0032] A start-up control module: used for the photovoltaic inverter to detect the input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and to start the photovoltaic inverter based on the input power;

[0033] Tracking module: used for the photovoltaic inverter to perform maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on the maximum power point tracking algorithm to obtain the maximum total power generation power;

[0034] Inversion operation module: used for the photovoltaic inverter to call the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtain the alternating current data to be output formed by the inversion;

[0035] Detection module: used for the photovoltaic inverter to perform harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal;

[0036] Filter output module: used for the photovoltaic inverter to filter the AC power data to be output based on the harmonic signals and the interharmonic signals, and input the filtered AC power data to be output into the distribution network based on the grid connection.

[0037] In addition, an embodiment of the present invention further provides a photovoltaic inverter, wherein the electronic device includes a processor and a memory, the memory is used to store instructions, and the processor is used to call the instructions in the memory so that the electronic device executes the photovoltaic inverter control method described in any one of the above.

[0038] In addition, an embodiment of the present invention further provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed on an electronic device, the electronic device executes the photovoltaic inverter control method as described in any one of the above.

[0039] In an embodiment of the present invention, a photovoltaic inverter detects input power of several photovoltaic cells in a photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power; performs maximum power point tracking processing on the total power generation; calls an inverter unit to perform an inversion operation on the received input direct current based on the tracking maximum total power generation, and obtains the AC power data to be output formed by the inversion; performs harmonic and interharmonic detection processing on the AC power data to be output; performs filtering processing on the AC power data to be output based on each harmonic signal and each interharmonic signal, and inputs the filtered AC power data to be output into the distribution network based on the grid connection; thereby realizing high-precision tracking processing of the power generation of the photovoltaic power generation field, thereby accurately obtaining the maximum total power generation, thereby realizing that the power generation efficiency of the photovoltaic power generation field can be effectively improved by tracking the maximum total power generation; and by performing harmonic and interharmonic detection on the AC power data to be output after inversion, filtering processing is performed to remove each harmonic and each interharmonic in the AC power data to be output, so as to ensure that the AC power data input to the distribution network will not cause the oscillation of the distribution network, and ensure the safe operation of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 is a flow chart of a photovoltaic inverter control method based on maximum power point tracking in an embodiment of the present invention;

[0042] Figure 2 is a flow chart of a photovoltaic inverter control method based on maximum power point tracking in another embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of the structure of a photovoltaic inverter control device based on maximum power point tracking in an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the structural composition of a photovoltaic inverter in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] For example, see Figure 1 , Figure 1 It is a flow chart of a photovoltaic inverter control method based on maximum power point tracking in an embodiment of the present invention.

[0047] like Figure 1 As shown, a photovoltaic inverter control method based on maximum power point tracking is applied to a photovoltaic inverter, one end of which is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a distribution network; the method comprises:

[0048] S101: The photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power;

[0049] In the specific implementation process of the present invention, the photovoltaic inverter detects the input power input by several photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power, including: when the photovoltaic inverter detects the input power input by several photovoltaic cells in the photovoltaic power generation field, extracts the input voltage data corresponding to the input power; compares and processes the input voltage data with the minimum starting voltage of the photovoltaic inverter, and starts and controls the photovoltaic inverter when the input voltage data is greater than or equal to the minimum starting voltage.

[0050] Specifically, the input end of the photovoltaic inverter is connected to a number of photovoltaic cells in the photovoltaic power field through a DC switch, that is, first, a number of photovoltaic cells in the photovoltaic power field are connected to the DC switch after passing string detection, and the output end of the photovoltaic inverter is connected to the distribution network.

[0051] The photovoltaic inverter has a starting condition, that is, the photovoltaic inverter needs to detect the input power of several photovoltaic cells in the photovoltaic power field by detection when it is not started, and when the input power of several photovoltaic cells in the photovoltaic power field is detected, it is necessary to extract the input voltage data corresponding to the input power; then compare the input voltage data with the minimum starting voltage of the photovoltaic inverter, and when the input voltage data is greater than or equal to the minimum starting voltage, start the photovoltaic inverter; if the input voltage data is less than the minimum starting voltage, the photovoltaic inverter will not start temporarily, and continue to detect the input power of several photovoltaic cells in the photovoltaic power field.

[0052] S102: the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain a tracked maximum total power generation power;

[0053] In the specific implementation process of the present invention, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field based on the maximum power point tracking algorithm to obtain the tracked maximum total power generation power, including: the photovoltaic inverter uses the three-point method based on the PV characteristic curve formed by the photovoltaic power field to perform maximum power point tracking processing on the total power generation power of the photovoltaic power field to obtain the tracked maximum total power generation power.

[0054] Further, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on the PV characteristic curve formed by the photovoltaic power field to obtain the maximum total power generation power, including: extracting three points a, b, and c from left to right near the peak point corresponding to the PV characteristic curve formed by the photovoltaic power field, and obtaining the power P corresponding to the three points a, b, and c. a , P b , P c and voltage U a , U b , U c ; Take the voltage U at point b b As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step; obtain the power P corresponding to the three points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <P c;P a <P b ,P c <P b ;P c <P b <P a After obtaining the position relationship, a power comparison flag Tag is set, the initial value of the Tag is 0, and the position of point b is adjusted according to the position relationship using the Tag in each judgment cycle. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P v =P max When , the maximum total power generation is obtained.

[0055] Further, the adjusting the position of b by using Tag according to the position relationship in each judgment cycle includes: when the position relationship is P a <P b <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of the three points a, b, and c; in the position relationship P a <P b ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of the three points a, b, and c; in the position relationship P c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated U aEqual to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

[0056] Specifically, in this embodiment, the maximum power point tracking (MPPT) algorithm is used to implement the maximum power point tracking of the total power generation power of the photovoltaic power plant; the MPPT algorithm can achieve efficient tracking under rapidly changing weather conditions, wherein the inverter efficiency of the photovoltaic inverter is: total inverter efficiency = MPPT tracking efficiency * inverter conversion efficiency; therefore, it can be known that when the photovoltaic cell conversion efficiency and the inverter conversion efficiency are constant, the MPPT tracking efficiency is particularly important for improving the power generation of the power station, and the MPPT tracking efficiency greatly affects the power generation of the power station.

[0057] MPPT tracking efficiency refers to the ratio of the actual input power obtained by the inverter from the photovoltaic cell to the maximum power that the photovoltaic cell can theoretically output; the higher the MPPT tracking efficiency, the better the MPPT response performance and the higher the inverter power generation. MPPT efficiency includes static MPPT efficiency and dynamic MPPT efficiency.

[0058] Static MPPT efficiency is the steady-state efficiency when the environment remains unchanged, and can be as high as possible. Since the open circuit voltage and short circuit current of photovoltaic cells are largely affected by the irradiation intensity and temperature, when the environmental conditions such as irradiation intensity and temperature change, the output power curve of photovoltaic cells also changes, so the optimal operating point of the system will change with the change of environmental factors. All changes in the external environment will lead to low dynamic efficiency; therefore, improving the dynamic MPPT efficiency is the key to improving the overall MPPT efficiency.

[0059] The technical solution adopts the MPPT algorithm based on the three-point method, which compares the three points by disturbing the PV curve of the photovoltaic array, and compares the output power of these three points to determine the disturbance direction and step size. Therefore, the judgment is more accurate, and at the same time, when the external environment changes greatly, it does not search blindly to avoid misjudgment.

[0060] The specific maximum power point tracking detailed process is as follows:

[0061] Extract three points a, b, and c from left to right near the peak point of the PV characteristic curve formed by the photovoltaic power generation field, and obtain the power P corresponding to the three points a, b, and c a , P b , P c and voltage U a , U b , U c; The power value can be calculated by multiplying the voltage and current; and the voltage U at point b b As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step; obtain the power P corresponding to the three points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <P c ;P a <P b ,P c <P b ;P c <P b <P a ; Since point a and point c are obtained based on point b, under normal circumstances, these three points and the maximum power point P max There are three types of position relationships: when point b has the maximum power point P max When the distance is far to the left, point c is also on P max In the case on the left, there is P a <P b <P c ; When the maximum power point P max Nearby, after increasing the step size ΔU, point c is at P max On the right side, there is P a <P b ,P c <P b ; When the maximum power point P max On the right, after reducing the step size ΔU, point a is also at the maximum power point P max In the case on the right, there is both P c <P b <P a After obtaining the positional relationship of the above three situations, a power comparison flag Tag is set, and the initial value of the Tag is 0. In each judgment cycle, the position of point b is adjusted according to the positional relationship using the Tag. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P b =P maxWhen , the maximum total power generation is obtained.

[0062] That is, in the position relationship P a <P b <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of points a, b, and c; a <P b ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of points a, b, and c; c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated U a Equal to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

[0063] There may also be misjudgment, that is, when the system detects P a ≥P b , then there is cloud cover, and then the detected c <P b , indicating that the light intensity changes rapidly; the change of environment may cause a variety of misjudgment states, which can be covered by Tag = 0; at this time, even with U b =U b , U a =U b -ΔU,U c =U a+2ΔU disturbance, the system operating point remains at the position before the rapid change of light intensity, and re-tracks to the maximum power point after the light intensity stabilizes; thus ensuring that when the external environment changes significantly, the system does not search blindly to avoid the occurrence of misjudgment.

[0064] S103: The photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtains the alternating current data to be output formed by the inversion;

[0065] In the specific implementation process of the present invention, the photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation to obtain the alternating current data to be output formed by the inversion, including: taking the tracked maximum total power generation as the actual input power of the photovoltaic inverter, and calling the inverter unit to perform an inversion operation on the input direct current corresponding to the actual input power to obtain the alternating current data to be output formed by the inversion.

[0066] Specifically, after tracking the maximum total power generation, the maximum total power generation is used as the maximum total power generation, and then the inverter unit is called to perform an inverter operation on the input DC power corresponding to the actual input power to obtain the AC power data to be output formed by the inverter.

[0067] S104: the photovoltaic inverter performs harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal;

[0068] In the specific implementation process of the present invention, because the AC power inverted by the photovoltaic inverter may contain harmonics and simple harmonics when performing the inversion operation, this may cause the distribution network to oscillate after being input into the distribution network, thereby causing unstable operation of the distribution network and posing a potential safety hazard in operation.

[0069] The sensor on the photovoltaic inverter collects the voltage waveform and current waveform in the AC power data to be output, and then separates each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal from the voltage waveform and the current waveform through the fundamental voltage signal and the fundamental current signal; and extracts each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal respectively; in this way, filtering operations can be performed subsequently according to the extracted each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal.

[0070] S105: The photovoltaic inverter performs filtering processing on the AC power data to be output based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on a grid-connected connection.

[0071] In the specific implementation process of the present invention, the photovoltaic inverter filters the AC power data to be output based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on the grid connection, including: performing parameter configuration processing on the filter unit of the photovoltaic inverter based on the harmonic signals and the interharmonic signals to form a configured filter unit, the filter unit is composed of an AC filter, an AC relay and an AC electromagnetic interference filter in sequence; filtering the AC power data to be output through the configured filter unit to obtain filtered AC power data to be output; and inputting the filtered AC power data to be output into the distribution network based on the grid connection.

[0072] Specifically, parameter configuration processing is performed on the filter unit of the photovoltaic inverter according to each harmonic signal and each interharmonic signal to form a configured filter unit, and then the AC power data to be output is filtered by passing the configured filter unit to obtain the filtered AC power data to be output; finally, the filtered AC power data to be output is input into the distribution network based on the grid connection; wherein the filter unit is composed of an AC filter, an AC relay and an AC electromagnetic interference filter in sequence; according to these each harmonic signal and each interharmonic signal, the filter parameters are configured in a targeted manner, so that the signal corresponding to the AC power data to be output can be accurately filtered out, so that the output filtered AC power data to be output will not cause the oscillation of the distribution network after being output to the distribution network, thereby ensuring the safe operation of the distribution network.

[0073] In an embodiment of the present invention, a photovoltaic inverter detects input power of several photovoltaic cells in a photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power; performs maximum power point tracking processing on the total power generation; calls an inverter unit to perform an inversion operation on the received input direct current based on the tracking maximum total power generation, and obtains the AC power data to be output formed by the inversion; performs harmonic and interharmonic detection processing on the AC power data to be output; performs filtering processing on the AC power data to be output based on each harmonic signal and each interharmonic signal, and inputs the filtered AC power data to be output into the distribution network based on the grid connection; thereby realizing high-precision tracking processing of the power generation of the photovoltaic power generation field, thereby accurately obtaining the maximum total power generation, thereby realizing that the power generation efficiency of the photovoltaic power generation field can be effectively improved by tracking the maximum total power generation; and by performing harmonic and interharmonic detection on the AC power data to be output after inversion, filtering processing is performed to remove each harmonic and each interharmonic in the AC power data to be output, so as to ensure that the AC power data input to the distribution network will not cause the oscillation of the distribution network, and ensure the safe operation of the distribution network.

[0074] For example 2, please refer to Figure 2 , Figure 2 It is a flow chart of a photovoltaic inverter control method based on maximum power point tracking in another embodiment of the present invention.

[0075] like Figure 2 As shown, a photovoltaic inverter control method based on maximum power point tracking is applied to a photovoltaic inverter, one end of which is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a distribution network; the method comprises:

[0076] S201: The photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power;

[0077] S202: The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain a tracked maximum total power generation power;

[0078] S203: taking the tracked maximum total generated power as the actual input power of the photovoltaic inverter, and calling the inversion unit to perform an inversion operation on the input direct current corresponding to the actual input power to obtain the inverted alternating current data to be output;

[0079] S204: the photovoltaic inverter performs harmonic and interharmonic detection processing on the output AC power data to obtain harmonic signals and interharmonic signals;

[0080] S205: performing parameter configuration processing on the filter unit of the photovoltaic inverter based on the harmonic signals and the interharmonic signals to form a configured filter unit, wherein the filter unit is composed of an AC filter, an AC relay, and an AC electromagnetic interference filter in sequence;

[0081] S206: filtering the to-be-output AC power data through the configured filtering unit to obtain filtered AC power data to be output;

[0082] S207: Inputting the filtered AC power data to be output into the distribution network based on the grid connection.

[0083] The specific implementation of the second embodiment can be found in the first embodiment, which will not be described in detail here.

[0084] For example 3, please refer to Figure 3 , Figure 3 It is a schematic diagram of the structural composition of a photovoltaic inverter control device based on maximum power point tracking in an embodiment of the present invention.

[0085] like Figure 3 As shown, a photovoltaic inverter control device based on maximum power point tracking is applied to a photovoltaic inverter, one end of which is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a distribution network; the device comprises:

[0086] A start-up control module 301 is used for the photovoltaic inverter to detect the input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and to start the photovoltaic inverter based on the input power;

[0087] In the specific implementation process of the present invention, the photovoltaic inverter detects the input power input by several photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power, including: when the photovoltaic inverter detects the input power input by several photovoltaic cells in the photovoltaic power generation field, extracts the input voltage data corresponding to the input power; compares and processes the input voltage data with the minimum starting voltage of the photovoltaic inverter, and starts and controls the photovoltaic inverter when the input voltage data is greater than or equal to the minimum starting voltage.

[0088] Specifically, the input end of the photovoltaic inverter is connected to a number of photovoltaic cells in the photovoltaic power field through a DC switch, that is, first, a number of photovoltaic cells in the photovoltaic power field are connected to the DC switch after passing string detection, and the output end of the photovoltaic inverter is connected to the distribution network.

[0089] The photovoltaic inverter has a starting condition, that is, the photovoltaic inverter needs to detect the input power of several photovoltaic cells in the photovoltaic power field by detection when it is not started, and when the input power of several photovoltaic cells in the photovoltaic power field is detected, it is necessary to extract the input voltage data corresponding to the input power; then compare the input voltage data with the minimum starting voltage of the photovoltaic inverter, and when the input voltage data is greater than or equal to the minimum starting voltage, start the photovoltaic inverter; if the input voltage data is less than the minimum starting voltage, the photovoltaic inverter will not start temporarily, and continue to detect the input power of several photovoltaic cells in the photovoltaic power field.

[0090] Tracking module 302: used for the photovoltaic inverter to perform maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on the maximum power point tracking algorithm to obtain the tracked maximum total power generation power;

[0091] In the specific implementation process of the present invention, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field based on the maximum power point tracking algorithm to obtain the tracked maximum total power generation power, including: the photovoltaic inverter uses the three-point method based on the PV characteristic curve formed by the photovoltaic power field to perform maximum power point tracking processing on the total power generation power of the photovoltaic power field to obtain the tracked maximum total power generation power.

[0092] Further, the photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on the PV characteristic curve formed by the photovoltaic power field to obtain the maximum total power generation power, including: extracting three points a, b, and c from left to right near the peak point corresponding to the PV characteristic curve formed by the photovoltaic power field, and obtaining the power P corresponding to the three points a, b, and c. a , P b , P c and voltage U a , U b , U c ; Take the voltage U at point b b As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step; obtain the power P corresponding to the three points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <Pc ;P a <P b ,P c <P b ;P c <P b <P a After obtaining the position relationship, a power comparison flag Tag is set, the initial value of the Tag is 0, and the position of point b is adjusted according to the position relationship using the Tag in each judgment cycle. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P b =P max When , the maximum total power generation is obtained.

[0093] Further, the adjusting the position of b by using Tag according to the position relationship in each judgment cycle includes: when the position relationship is P a <P b <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of the three points a, b, and c; in the position relationship P a <P b ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of the three points a, b, and c; in the position relationship P c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated Ua Equal to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

[0094] Specifically, in this embodiment, the maximum power point tracking (MPPT) algorithm is used to implement the maximum power point tracking of the total power generation power of the photovoltaic power plant; the MPPT algorithm can achieve efficient tracking under rapidly changing weather conditions, wherein the inverter efficiency of the photovoltaic inverter is: total inverter efficiency = MPPT tracking efficiency * inverter conversion efficiency; therefore, it can be known that when the photovoltaic cell conversion efficiency and the inverter conversion efficiency are constant, the MPPT tracking efficiency is particularly important for improving the power generation of the power station, and the MPPT tracking efficiency greatly affects the power generation of the power station.

[0095] MPPT tracking efficiency refers to the ratio of the actual input power obtained by the inverter from the photovoltaic cell to the maximum power that the photovoltaic cell can theoretically output; the higher the MPPT tracking efficiency, the better the MPPT response performance and the higher the inverter power generation. MPPT efficiency includes static MPPT efficiency and dynamic MPPT efficiency.

[0096] Static MPPT efficiency is the steady-state efficiency when the environment remains unchanged, and can be as high as possible. Since the open circuit voltage and short circuit current of photovoltaic cells are largely affected by the irradiation intensity and temperature, when the environmental conditions such as irradiation intensity and temperature change, the output power curve of photovoltaic cells also changes, so the optimal operating point of the system will change with the change of environmental factors. All changes in the external environment will lead to low dynamic efficiency; therefore, improving the dynamic MPPT efficiency is the key to improving the overall MPPT efficiency.

[0097] The technical solution adopts the MPPT algorithm based on the three-point method, which compares the three points by disturbing the PV curve of the photovoltaic array, and compares the output power of these three points to determine the disturbance direction and step size. Therefore, the judgment is more accurate, and at the same time, when the external environment changes greatly, it does not search blindly to avoid misjudgment.

[0098] The specific maximum power point tracking detailed process is as follows:

[0099] Extract three points a, b, and c from left to right near the peak point of the PV characteristic curve formed by the photovoltaic power generation field, and obtain the power P corresponding to the three points a, b, and c a , P b , P c and voltage U a , U b , U c; The power value can be calculated by multiplying the voltage and current; and the voltage U at point b b As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step; obtain the power P corresponding to the three points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <P c ;P a <P b ,P c <P b ;P c <P b <P a ; Since point a and point c are obtained based on point b, under normal circumstances, these three points and the maximum power point P max There are three types of position relationships: when point b has the maximum power point P max When the distance is far to the left, point c is also on P max In the case on the left, there is P a <P b <P c ; When the maximum power point P max Nearby, after increasing the step size ΔU, point c is at P max On the right side, there is P a <P b ,P c <P b ; When the maximum power point P max On the right, after reducing the step size ΔU, point a is also at the maximum power point P max In the case on the right, there is both P c <P b <P a After obtaining the positional relationship of the above three situations, a power comparison flag Tag is set, and the initial value of the Tag is 0. In each judgment cycle, the position of point b is adjusted according to the positional relationship using the Tag. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P b =P maxWhen , the maximum total power generation is obtained.

[0100] That is, in the position relationship P a <P b <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of points a, b, and c; a <P b ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of points a, b, and c; c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated U a Equal to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

[0101] There may also be misjudgment, that is, when the system detects P a ≥P b , then there is cloud cover, and then the detected c <P b , indicating that the light intensity changes rapidly; the change of environment may cause a variety of misjudgment states, which can be covered by Tag = 0; at this time, even with U b =U b , U a =U b -ΔU,U c =U a+2ΔU disturbance, the system operating point remains at the position before the rapid change of light intensity, and re-tracks to the maximum power point after the light intensity stabilizes; thus ensuring that when the external environment changes significantly, the system does not search blindly to avoid the occurrence of misjudgment.

[0102] Inversion operation module 303: used for the photovoltaic inverter to call the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtain the alternating current data to be output formed by the inversion;

[0103] In the specific implementation process of the present invention, the photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation to obtain the alternating current data to be output formed by the inversion, including: taking the tracked maximum total power generation as the actual input power of the photovoltaic inverter, and calling the inverter unit to perform an inversion operation on the input direct current corresponding to the actual input power to obtain the alternating current data to be output formed by the inversion.

[0104] Specifically, after tracking the maximum total power generation, the maximum total power generation is used as the maximum total power generation, and then the inverter unit is called to perform an inverter operation on the input DC power corresponding to the actual input power to obtain the AC power data to be output formed by the inverter.

[0105] Detection module 304: used for the photovoltaic inverter to perform harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal;

[0106] In the specific implementation process of the present invention, because the AC power inverted by the photovoltaic inverter may contain harmonics and simple harmonics when performing the inversion operation, this may cause the distribution network to oscillate after being input into the distribution network, thereby causing unstable operation of the distribution network and posing a potential safety hazard in operation.

[0107] The sensor on the photovoltaic inverter collects the voltage waveform and current waveform in the AC power data to be output, and then separates each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal from the voltage waveform and the current waveform through the fundamental voltage signal and the fundamental current signal; and extracts each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal respectively; in this way, filtering operations can be performed subsequently according to the extracted each voltage harmonic signal, each voltage interharmonic signal, each current harmonic signal and each current interharmonic signal.

[0108] The filtering output module 305 is used for the photovoltaic inverter to filter the AC power data to be output based on the harmonic signals and the interharmonic signals, and input the filtered AC power data to be output into the distribution network based on the grid connection.

[0109] In the specific implementation process of the present invention, the photovoltaic inverter filters the AC power data to be output based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on the grid connection, including: performing parameter configuration processing on the filter unit of the photovoltaic inverter based on the harmonic signals and the interharmonic signals to form a configured filter unit, the filter unit is composed of an AC filter, an AC relay and an AC electromagnetic interference filter in sequence; filtering the AC power data to be output through the configured filter unit to obtain filtered AC power data to be output; and inputting the filtered AC power data to be output into the distribution network based on the grid connection.

[0110] Specifically, parameter configuration processing is performed on the filter unit of the photovoltaic inverter according to each harmonic signal and each interharmonic signal to form a configured filter unit, and then the AC power data to be output is filtered by passing the configured filter unit to obtain the filtered AC power data to be output; finally, the filtered AC power data to be output is input into the distribution network based on the grid connection; wherein the filter unit is composed of an AC filter, an AC relay and an AC electromagnetic interference filter in sequence; according to these each harmonic signal and each interharmonic signal, the filter parameters are configured in a targeted manner, so that the signal corresponding to the AC power data to be output can be accurately filtered out, so that the output filtered AC power data to be output will not cause the oscillation of the distribution network after being output to the distribution network, thereby ensuring the safe operation of the distribution network.

[0111] In an embodiment of the present invention, a photovoltaic inverter detects input power of several photovoltaic cells in a photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power; performs maximum power point tracking processing on the total power generation; calls an inverter unit to perform an inversion operation on the received input direct current based on the tracking maximum total power generation, and obtains the AC power data to be output formed by the inversion; performs harmonic and interharmonic detection processing on the AC power data to be output; performs filtering processing on the AC power data to be output based on each harmonic signal and each interharmonic signal, and inputs the filtered AC power data to be output into the distribution network based on the grid connection; thereby realizing high-precision tracking processing of the power generation of the photovoltaic power generation field, thereby accurately obtaining the maximum total power generation, thereby realizing that the power generation efficiency of the photovoltaic power generation field can be effectively improved by tracking the maximum total power generation; and by performing harmonic and interharmonic detection on the AC power data to be output after inversion, filtering processing is performed to remove each harmonic and each interharmonic in the AC power data to be output, so as to ensure that the AC power data input to the distribution network will not cause the oscillation of the distribution network, and ensure the safe operation of the distribution network.

[0112] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, a photovoltaic inverter control method of any one of the above embodiments is implemented. The computer-readable storage medium includes, but is not limited to, any type of disk (including floppy disk, hard disk, optical disk, CD-ROM, and magneto-optical disk), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (EraSable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic card or optical card. That is, the storage device includes any medium that can store or transmit information in a readable form by a device (for example, a computer, a mobile phone), which can be a read-only memory, a disk or an optical disk, etc.

[0113] An embodiment of the present invention further provides a computer application program, which runs on a computer and is used to execute the photovoltaic inverter control method of any one of the above embodiments.

[0114] also, Figure 4 It is a schematic diagram of the structural composition of a photovoltaic inverter in an embodiment of the present invention.

[0115] The embodiment of the present invention further provides a photovoltaic inverter, such as Figure 4 The photovoltaic inverter includes a processor 402, a memory 403, an input unit 404, a display unit 405 and other devices. Those skilled in the art can understand that Figure 4 The structural components of the photovoltaic inverter shown do not constitute a limitation on all devices, and may include more or fewer components than shown, or combine certain components. The memory 403 can be used to store the application 401 and various functional modules, and the processor 402 runs the application 401 stored in the memory 403, thereby executing various functional applications and data processing of the device. The memory can be an internal memory or an external memory, or include both internal and external memories. The internal memory may include a read-only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, or a random access memory. The external memory may include a hard disk, a floppy disk, a ZIP disk, a U disk, a magnetic tape, etc. The memory disclosed in the present invention includes but is not limited to these types of memories. The memory disclosed in the present invention is only an example and not a limitation.

[0116] The input unit 404 is used to receive the input of the signal and the keyword input by the user. The input unit 404 may include a touch panel and other input devices. The touch panel can collect the user's touch operation on or near it (such as the user's operation on or near the touch panel using any suitable object or accessory such as a finger, stylus, etc.), and drive the corresponding connection device according to a pre-set program; other input devices may include but are not limited to one or more of a physical keyboard, a function key (such as a playback control key, a switch key, etc.), a trackball, a mouse, a joystick, etc. The display unit 405 can be used to display the information input by the user or the information provided to the user and various menus of the terminal device. The display unit 405 can be in the form of a liquid crystal display, an organic light emitting diode, etc. The processor 402 is the control center of the terminal device, which uses various interfaces and lines to connect the various parts of the entire device, and executes various functions and processes data by running or executing software programs and / or modules stored in the memory 403, and calling the data stored in the memory.

[0117] As an embodiment, the photovoltaic inverter includes: one or more processors 402, a memory 403, and one or more applications 401, wherein the one or more applications 401 are stored in the memory 403 and are configured to be executed by the one or more processors 402, and the one or more applications 401 are configured to execute the photovoltaic inverter control method in any one of the above embodiments.

[0118] In an embodiment of the present invention, a photovoltaic inverter detects input power of several photovoltaic cells in a photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power; performs maximum power point tracking processing on the total power generation; calls an inverter unit to perform an inversion operation on the received input direct current based on the tracking maximum total power generation, and obtains the AC power data to be output formed by the inversion; performs harmonic and interharmonic detection processing on the AC power data to be output; performs filtering processing on the AC power data to be output based on each harmonic signal and each interharmonic signal, and inputs the filtered AC power data to be output into the distribution network based on the grid connection; thereby realizing high-precision tracking processing of the power generation of the photovoltaic power generation field, thereby accurately obtaining the maximum total power generation, thereby realizing that the power generation efficiency of the photovoltaic power generation field can be effectively improved by tracking the maximum total power generation; and by performing harmonic and interharmonic detection on the AC power data to be output after inversion, filtering processing is performed to remove each harmonic and each interharmonic in the AC power data to be output, so as to ensure that the AC power data input to the distribution network will not cause the oscillation of the distribution network, and ensure the safe operation of the distribution network.

[0119] In addition, the above is a detailed introduction to a photovoltaic inverter control method based on maximum power point tracking and related devices provided by an embodiment of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A photovoltaic inverter control method based on maximum power point tracking, characterized in that: Applied to a photovoltaic inverter, one end of the photovoltaic inverter is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a power distribution network; the method comprises: The photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power; The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain the tracked maximum total power generation power; The photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtains the alternating current data to be output formed by the inversion; The photovoltaic inverter performs harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal; The photovoltaic inverter performs filtering processing on the AC power data to be output based on the harmonic signals and the interharmonic signals, and inputs the filtered AC power data to be output into the distribution network based on the grid connection.

2. The photovoltaic inverter control method according to claim 1, characterized in that: The photovoltaic inverter detects input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and starts and controls the photovoltaic inverter based on the input power, including: When the photovoltaic inverter detects the input power input by a plurality of photovoltaic cells in the photovoltaic power generation field, it extracts the input voltage data corresponding to the input power; The input voltage data is compared with the minimum starting voltage of the photovoltaic inverter, and when the input voltage data is greater than or equal to the minimum starting voltage, the photovoltaic inverter is started and controlled.

3. The photovoltaic inverter control method according to claim 1, characterized in that: The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on a maximum power point tracking algorithm to obtain the tracked maximum total power generation power, including: The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on the PV characteristic curve formed by the photovoltaic power field to obtain the tracked maximum total power generation power.

4. The photovoltaic inverter control method according to claim 3, characterized in that: The photovoltaic inverter performs maximum power point tracking processing on the total power generation power of the photovoltaic power field using a three-point method based on the PV characteristic curve formed by the photovoltaic power field to obtain the maximum total power generation power, including: Three points a, b, and c are extracted from left to right near the peak point of the PV characteristic curve formed by the photovoltaic power generation field, and the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; The voltage U at point b b As a reference, point c and point a are the working points corresponding to one step in the positive and negative directions of point b, and the voltage at point c is U c =U b +ΔU, the voltage at point a is U a =U b -ΔU, where ΔU is the voltage difference of one step; Get the power P corresponding to points a, b, and c a , P b , P c The positional relationship between the two includes P a <P b <P c ;P a <P b ,P c <P b ;P c <P b <P a ; After obtaining the position relationship, a power comparison flag Tag is set, the initial value of the Tag is 0, and the position of point b is adjusted according to the position relationship using the Tag in each judgment cycle. After the adjustment, the power P corresponding to the three points a, b, and c is obtained. a , P b , P c and voltage U a , U b , U c ; until P b =P max When , the maximum total power generation is obtained.

5. The photovoltaic inverter control method according to claim 4, characterized in that: The step of adjusting the position of b by using the tag according to the position relationship in each judgment cycle includes: In the position relationship P a <P v <P c When the Tag is adjusted to Tag = 2, the execution program is as follows: c Give U b , forming an updated U b , updated U a Equal to the updated U b Subtract 1 ΔU, the updated U c Equal to the updated U a Add 2 ΔU to form the updated positions of points a, b, and c; In the position relationship P a <P v ,P c <P b When the Tag is adjusted to Tag = 0, the execution program is to keep U a and U b The same as U c Adjust to U a Add 1 ΔU to form the updated positions of points a, b, and c; In the position relationship P c <P b <P a When the Tag is adjusted to Tag = -2, the execution program is as follows: a Give U b , forming an updated U b , updated U c Equal to the updated U b Add 1 ΔU, the updated U a Equal to the updated U c Subtract 2 ΔU to form the updated positions of points a, b, and c.

6. The photovoltaic inverter control method according to claim 1, characterized in that: The photovoltaic inverter calls the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtains the alternating current data to be output formed by the inversion, including: The tracked maximum total power generation is used as the actual input power of the photovoltaic inverter, and the inverter unit is called to perform an inversion operation on the input direct current corresponding to the actual input power to obtain the alternating current data to be output formed by the inversion.

7. The photovoltaic inverter control method according to claim 1, characterized in that: The photovoltaic inverter performs filtering processing on the to-be-output AC power data based on the harmonic signals and the interharmonic signals, and inputs the filtered to-be-output AC power data into the distribution network based on the grid connection, including: Based on the harmonic signals and the interharmonic signals, parameter configuration processing is performed on the filter unit of the photovoltaic inverter to form a configured filter unit, wherein the filter unit is composed of an AC filter, an AC relay, and an AC electromagnetic interference filter in sequence; The AC power data to be output is filtered by the configured filtering unit to obtain filtered AC power data to be output; The filtered alternating current data to be output is input into the power distribution network based on the grid connection.

8. A photovoltaic inverter control device based on maximum power point tracking, characterized in that: Applied to a photovoltaic inverter, one end of the photovoltaic inverter is connected to a plurality of photovoltaic cells in a photovoltaic power generation field through a DC switch, and the other end is connected to a power distribution network; the device comprises: A start-up control module: used for the photovoltaic inverter to detect the input power of a plurality of photovoltaic cells in the photovoltaic power generation field, and to start the photovoltaic inverter based on the input power; Tracking module: used for the photovoltaic inverter to perform maximum power point tracking processing on the total power generation power of the photovoltaic power plant based on the maximum power point tracking algorithm to obtain the maximum total power generation power; Inversion operation module: used for the photovoltaic inverter to call the inverter unit to perform an inversion operation on the received input direct current based on the tracked maximum total power generation, and obtain the alternating current data to be output formed by the inversion; Detection module: used for the photovoltaic inverter to perform harmonic and interharmonic detection processing on the output AC power data to obtain each harmonic signal and each interharmonic signal; Filter output module: used for the photovoltaic inverter to filter the AC power data to be output based on the harmonic signals and the interharmonic signals, and input the filtered AC power data to be output into the distribution network based on the grid connection.

9. A photovoltaic inverter, wherein the electronic device comprises a processor and a memory, characterized in that: The memory is used to store instructions, and the processor is used to call the instructions in the memory, so that the electronic device executes the photovoltaic inverter control method according to any one of claims 1 to claim 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed on an electronic device, the electronic device executes the photovoltaic inverter control method according to any one of claims 1 to 7.

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