Three-phase grid-connected inverter firing method, system, controller and readable storage medium

Abstract

The application discloses a three-phase grid-connected inverter wave generation method, system, controller and readable storage medium, and the method comprises the following steps: acquiring three-phase modulation wave signals output by a three-phase control loop of the inverter, and extracting maximum values and minimum values from the three-phase modulation wave signals; calculating zero sequence injection components of SVPWM wave generation control based on the extracted maximum values and minimum values; calculating zero sequence injection components of DPWM wave generation control based on the extracted maximum values and minimum values; selecting the optimal one of the zero sequence injection components of SVPWM wave generation control and the zero sequence injection components of DPWM wave generation control as the final three-phase modulation wave zero sequence injection component; and adding the final three-phase modulation wave zero sequence injection component to the three-phase modulation wave signals output by the three-phase control loop respectively to obtain final three-phase modulation wave signals. Thus, the application reduces switching loss, improves equipment efficiency, and improves system stability.

Description

Technical Field

[0001] The present invention relates to the field of three-phase grid-connected inverters, and in particular to a wave generation method, system, controller and readable storage medium for a three-phase grid-connected inverter. Background Art

[0002] Three-phase grid-connected inverters typically use SPWM or SVPWM control. The SVPWM square wave method improves DC voltage utilization compared to the SPWM method. Three-phase grid-connected inverters can also use DPWM control, which reduces switching losses and improves efficiency.

[0003] Three-phase grid-connected inverters use SPWM or SVPWM control, which achieves high current sinusoidality and low total harmonic distortion (THDI). However, near maximum current, the transistors must constantly switch at high frequencies, resulting in high switching losses and low efficiency, impacting the device's thermal performance. In contrast, three-phase grid-connected inverters use traditional DPWM control, which disables the transistors near maximum current, effectively reducing switching losses and improving efficiency. However, at low modulation ratios, the modulation wave is not monotonic, causing LC filter resonance and common-mode voltage jumps at the modulation wave's zero crossing in low-frequency systems, leading to system instability. Current sinusoidality and total harmonic distortion are also poor.

[0004] The above information disclosed in this Background section is included only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is currently known to a person of ordinary skill in the art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a three-phase grid-connected inverter wave generation method, system, controller and readable storage medium in response to the above-mentioned defects of the prior art.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] On the one hand, a three-phase grid-connected inverter wave control method is constructed, the method comprising:

[0008] Obtaining a three-phase modulation wave signal output by a three-phase control loop of the inverter, and extracting a maximum value and a minimum value therefrom;

[0009] The zero-sequence injection component of SVPWM wave control is calculated based on the extracted maximum and minimum values;

[0010] The zero-sequence injection component of DPWM wave control is calculated based on the extracted maximum and minimum values;

[0011] Based on the zero-sequence injection component of SVPWM wave control and the zero-sequence injection component of DPWM wave control, the optimal one is selected as the final zero-sequence injection component of the three-phase modulation wave;

[0012] The three-phase modulation wave signals output by the three-phase control loop are respectively added with the final three-phase modulation wave zero-sequence injection component to obtain the final three-phase modulation wave signal.

[0013] Furthermore, in the three-phase grid-connected inverter wave generation control method described in the present invention, the zero-sequence injection component for SVPWM wave generation control is calculated based on the extracted maximum value and minimum value, specifically including: adding the extracted maximum value and the extracted minimum value and then multiplying the result by a preset proportional coefficient to obtain the zero-sequence injection component for SVPWM wave generation control.

[0014] Furthermore, in the three-phase grid-connected inverter wave generation control method of the present invention, the zero-sequence injection component of the DPWM wave generation control is calculated based on the extracted maximum and minimum values, specifically including:

[0015] Calculate the difference between 1 and the extracted maximum value as the first candidate value;

[0016] Calculate the difference between -1 and the extracted minimum value as the second candidate value;

[0017] When the absolute value of the first candidate value is greater than or equal to the absolute value of the second candidate value, the zero-sequence injection component of the DPWM wave control is equal to the first candidate value;

[0018] When the absolute value of the first candidate value is smaller than the absolute value of the second candidate value, the zero-sequence injection component of the DPWM wave control is equal to the second candidate value.

[0019] Furthermore, in the three-phase grid-connected inverter wave generation control method of the present invention, the optimal one of the zero-sequence injection component based on SVPWM wave generation control and the zero-sequence injection component based on DPWM wave generation control is selected as the final three-phase modulation wave zero-sequence injection component, which specifically includes:

[0020] When the absolute value of the zero-sequence injection component of the SVPWM wave control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final zero-sequence injection component of the three-phase modulation wave is equal to the zero-sequence injection component of the DPWM wave control;

[0021] When the absolute value of the zero-sequence injection component of the SVPWM wave control is smaller than the absolute value of the zero-sequence injection component of the DPWM wave control, the final zero-sequence injection component of the three-phase modulation wave is equal to the zero-sequence injection component of the SVPWM wave control.

[0022] In the second aspect, a three-phase grid-connected inverter wave control system is constructed, the system comprising:

[0023] a maximum value extraction module configured to obtain the three-phase modulated wave signal output by the three-phase control loop of the inverter and extract the maximum value and the minimum value therefrom;

[0024] A first zero-sequence injection component calculation module is configured to calculate the zero-sequence injection component of the SVPWM wave control based on the extracted maximum value and minimum value;

[0025] A second zero-sequence injection component calculation module is configured to calculate the zero-sequence injection component of the DPWM wave control based on the extracted maximum value and minimum value;

[0026] The zero-sequence injection component selection module is configured to select the optimal one as the final three-phase modulation wave zero-sequence injection component based on the zero-sequence injection component of the SVPWM wave control and the zero-sequence injection component of the DPWM wave control;

[0027] The three-phase modulation wave signal output module is configured to add the final three-phase modulation wave zero-sequence injection component to the three-phase modulation wave signals output by the three-phase control loop to obtain the final three-phase modulation wave signal.

[0028] Furthermore, in the three-phase grid-connected inverter wave generation control system of the present invention, the first zero-sequence injection component calculation module includes:

[0029] a first adder, configured to add the extracted maximum value to the extracted minimum value;

[0030] A multiplier is connected to the first adder and is used to multiply the first adder by a preset proportional coefficient to obtain a zero-sequence injection component for SVPWM wave generation control.

[0031] Furthermore, in the three-phase grid-connected inverter wave generation control system of the present invention, the second zero-sequence injection component calculation module includes:

[0032] a first subtractor, configured to calculate a difference between 1 and the extracted maximum value as a first candidate value;

[0033] a second subtractor, configured to calculate a difference between -1 and the extracted minimum value as a second candidate value;

[0034] The first absolute value comparator is configured to: when the absolute value of the first candidate value is greater than or equal to the absolute value of the second candidate value, ensure that the zero-sequence injection component of the SVPWM wave generation control is equal to the first candidate value; and when the absolute value of the first candidate value is less than the absolute value of the second candidate value, ensure that the zero-sequence injection component of the SVPWM wave generation control is equal to the second candidate value.

[0035] Furthermore, in the three-phase grid-connected inverter wave generation control system of the present invention, the zero-sequence injection component selection module includes:

[0036] The second absolute value comparator is used to ensure that, when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave generation control, the final zero-sequence injection component of the three-phase modulated wave is equal to the zero-sequence injection component of the DPWM wave generation control; and when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is less than the absolute value of the zero-sequence injection component of the DPWM wave generation control, the final zero-sequence injection component of the three-phase modulated wave is equal to the zero-sequence injection component of the SVPWM wave generation control.

[0037] In a third aspect, a three-phase grid-connected inverter wave generator controller is constructed, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the method described above are implemented.

[0038] In a fourth aspect, a readable storage medium is constructed, which stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any of the above items are implemented.

[0039] The three-phase grid-connected inverter wave generation method, system, controller, and readable storage medium of the present invention have the following beneficial effects: the present invention is equivalent to a wave generation mode that combines SVPWM and DPWM, avoiding the problems of the traditional DPWM wave generation mode when the modulation wave is controlled at a low modulation ratio, resulting in non-monotonic modulation wave in the low-frequency system, LC resonance of the LC filter, and common-mode voltage jumps when the modulation wave crosses zero, leading to system instability and poor current sinusoidality and total harmonic distortion. At the same time, it avoids the problem of the SPWM and SVPWM wave generation modes when the current is controlled near the maximum, resulting in high switching losses, low efficiency, and impact on the thermal performance of the equipment. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. Those skilled in the art can also derive other drawings based on the provided drawings without inventive work.

[0041] Figure 1 It is a flow chart of the wave generation method of the three-phase grid-connected inverter of the present invention;

[0042] Figure 2 This is a schematic diagram of a specific embodiment of the three-phase grid-connected inverter wave generation method of the present invention;

[0043] Figure 3It is a schematic diagram of a three-phase grid-connected inverter firing system of the present application. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The drawings show typical embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features in the embodiments of the present application and the embodiments can be combined with each other without conflict.

[0045] Embodiment one

[0046] The three-phase modulation wave signals output by the three-phase control loop of the inverter are respectively denoted as Va, Vb, and Vc. In the prior art, the three-phase modulation wave signals Va, Vb, and Vc output by the three-phase control loop are directly used for firing, for example, the generated modulation wave signals Va, Vb, and Vc are compared with a fixed frequency carrier signal for firing. If the amplitude of the modulation wave is higher than the carrier signal, a high level (the switching device of the inverter is turned on) is generated; otherwise, a low level (the switching device of the inverter is turned off) is generated. The idea of the present application is that before the existing three-phase modulation wave signals Va, Vb, and Vc are compared with the carrier, they are processed based on the three-phase grid-connected inverter firing control method of the present application. This method combines SVPWM firing with DPWM firing to generate a new zero sequence injection component, reduces the switching loss, improves the equipment efficiency, and at the same time improves the system stability.

[0047] Reference Figure 1 The three-phase grid-connected inverter firing control method of the present application is suitable for being executed by a controller of an inverter, and the method comprises:

[0048] S101: obtaining three-phase modulation wave signals output by a three-phase control loop of the inverter, and extracting the maximum value and the minimum value therefrom;

[0049] The generation process of the three-phase modulation wave signals Va, Vb, and Vc output by the three-phase control loop is already existing and is not the improvement point of the present application. The three-phase control loop generally contains one or more feedbacks, and the purpose is to maintain the stability of the output voltage or current through closed-loop control. A typical control loop includes outer loop control and inner loop control, the outer loop control is responsible for setting the target value of the output voltage or current, and the inner loop control adjusts the actual output according to the target value set by the outer loop. The present application executes this step S101 immediately after the three-phase control loop outputs the three-phase modulation wave signals Va, Vb, and Vc, for example, Figure 2As shown, the embodiment of the present application is to take the maximum of three-phase modulation wave signals Va, Vb, Vc output from the three-phase control loop and record it as Vmax, and take the minimum of Va, Vb, Vc and record it as Vmin.

[0050] S102: calculating the zero sequence injection component for SVPWM wave control based on the extracted maximum value and minimum value;

[0051] Reference Figure 2 The calculating the zero sequence injection component for SVPWM wave control based on the extracted maximum value and minimum value specifically includes: adding the extracted maximum value Vmax to the extracted minimum value Vmin and multiplying the preset proportionality coefficient K to obtain the zero sequence injection component for SVPWM wave control, and the zero sequence injection component is recorded as V0sv, that is, V0sv=K*(Vmax+Vmin).

[0052] The proportionality coefficient K herein has a value range of 0 to 1.

[0053] S103: calculating the zero sequence injection component for DPWM wave control based on the extracted maximum value and minimum value;

[0054] Reference Figure 2 Suppose that the zero sequence injection component for DPWM wave control is recorded as V0dp, and the calculating the zero sequence injection component for DPWM wave control based on the extracted maximum value and minimum value specifically includes:

[0055] Calculating the difference (that is, 1-Vmax) between 1 and the extracted maximum value Vmax, and taking it as a first candidate value; it needs to be explained that Va, Vb, Vc in the present application are values less than or equal to 1 obtained by normalizing (generally dividing by half of bus voltage U 母 );

[0056] Calculating the difference (that is, -1-Vmin) between -1 and the extracted minimum value Vmin, and taking it as a second candidate value;

[0057] When the absolute value (that is, |1-Vmax|) of the first candidate value is greater than or equal to the absolute value (that is, |-1-Vmin|) of the second candidate value, then the zero sequence injection component V0dp for DPWM wave control is equal to the first candidate value;

[0058] When the absolute value (that is, |1-Vmax|) of the first candidate value is less than the absolute value (that is, |-1-Vmin|) of the second candidate value, then the zero sequence injection component V0dp for DPWM wave control is equal to the second candidate value.

[0059] S104: selecting the optimal one based on the zero-sequence injection component of the SVPWM wave control and the zero-sequence injection component of the DPWM wave control as the final zero-sequence injection component of the three-phase modulation wave;

[0060] refer to Figure 2 Assuming that the final three-phase modulation wave zero-sequence injection component is recorded as V0fianl, the zero-sequence injection component based on SVPWM wave control and the zero-sequence injection component based on DPWM wave control are selected as the final three-phase modulation wave zero-sequence injection component, specifically including:

[0061] When the absolute value of the zero-sequence injection component of the SVPWM wave control |V0sv| is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control |V0dp|, the final three-phase modulation wave zero-sequence injection component V0fianl is equal to the zero-sequence injection component V0dp of the DPWM wave control;

[0062] When the absolute value of the zero-sequence injection component |V0sv| of the SVPWM wave control is smaller than the absolute value of the zero-sequence injection component |V0dp| of the DPWM wave control, the final three-phase modulation wave zero-sequence injection component V0fianl is equal to the zero-sequence injection component V0sv of the SVPWM wave control.

[0063] S105: Add the final three-phase modulation wave zero-sequence injection component to the three-phase modulation wave signals output by the three-phase control loop to obtain the final three-phase modulation wave signals.

[0064] Assuming that the final output modulation wave signals are Vafinal, Vbfinal, and Vcfinal, it means:

[0065] Vafinal=Va+V0fianl;

[0066] Vbfinal=Vb+V0fianl;

[0067] Vcfinal=Vc+V0fianl;

[0068] After obtaining Vafinal, Vbfinal, and Vcfinal, they can be used to generate drive signals using established methods. For example, assuming the inverter includes three parallel-connected bridge arms, each consisting of upper and lower switches connected in series, with their drive signals complementary. Vafinal, Vbfinal, and Vcfinal can be compared with the carrier to generate three PWM waveforms, denoted as PWMa, PWMb, and PWMc. PWMa, PWMb, and PWMc can then be used to drive the upper transistors of the three-phase bridge arms, while PWMa, PWMb, and PWMc can be flipped to drive the lower transistors.

[0069] This embodiment proposes a new zero-sequence component injection method for DPWM generation. This avoids the problems of conventional DPWM generation methods, such as non-monotonic modulation at low modulation ratios, which can cause LC filter resonance in low-frequency systems and common-mode voltage jumps when the modulation wave crosses zero, leading to system instability and poor current sinusoidality and THDi. It also avoids the problem of SPWM and SVPWM generation methods, which, when controlled near maximum current, require constant high-frequency switching of the transistors, resulting in high switching losses, low efficiency, and impact on the device's thermal performance. In summary, this embodiment reduces switching losses, improves device efficiency, and enhances system stability.

[0070] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a program. The program can be stored in a storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods.

[0071] Example 2

[0072] refer to Figure 3 Based on the same inventive concept, the present invention also constructs a three-phase grid-connected inverter wave control system, including:

[0073] A maximum value extraction module 201 is configured to obtain a three-phase modulated wave signal output by a three-phase control loop of the inverter and extract a maximum value and a minimum value therefrom;

[0074] A first zero-sequence injection component calculation module 202 is configured to calculate the zero-sequence injection component of the SVPWM wave control based on the extracted maximum value and minimum value;

[0075] A second zero-sequence injection component calculation module 203 is configured to calculate the zero-sequence injection component of the DPWM wave control based on the extracted maximum value and minimum value;

[0076] The zero-sequence injection component selection module 204 is configured to select the optimal one as the final three-phase modulation wave zero-sequence injection component based on the zero-sequence injection component of the SVPWM wave generation control and the zero-sequence injection component of the DPWM wave generation control;

[0077] The three-phase modulated wave signal output module 205 is configured to add the final three-phase modulated wave zero-sequence injection component to the three-phase modulated wave signals output by the three-phase control loop to obtain the final three-phase modulated wave signals.

[0078] Wherein, the first zero-sequence injection component calculation module 202 includes:

[0079] a first adder, configured to add the extracted maximum value to the extracted minimum value;

[0080] A multiplier is connected to the first adder and is used to multiply the first adder by a preset proportional coefficient to obtain a zero-sequence injection component for SVPWM wave generation control.

[0081] Wherein, the second zero-sequence injection component calculation module 203 includes:

[0082] a first subtractor, configured to calculate a difference between 1 and the extracted maximum value as a first candidate value;

[0083] a second subtractor, configured to calculate a difference between -1 and the extracted minimum value as a second candidate value;

[0084] a first absolute value comparator, configured to: when the absolute value of the first candidate value is greater than or equal to the absolute value of the second candidate value, ensure that the zero-sequence injection component of the DPWM wave generation control is equal to the first candidate value; and when the absolute value of the first candidate value is less than the absolute value of the second candidate value, ensure that the zero-sequence injection component of the DPWM wave generation control is equal to the second candidate value.

[0085] The zero-sequence injection component selection module 204 includes a second absolute value comparator, which is used to, when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave generation control, ensure that the final three-phase modulation wave zero-sequence injection component is equal to the zero-sequence injection component of the DPWM wave generation control; when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is less than the absolute value of the zero-sequence injection component of the DPWM wave generation control, ensure that the final three-phase modulation wave zero-sequence injection component is equal to the zero-sequence injection component of the SVPWM wave generation control.

[0086] The functions of each functional module in this embodiment can be specifically implemented according to the method in the above method embodiment. The specific implementation process can refer to the description of the above method embodiment, which will not be repeated here.

[0087] Example 3

[0088] Based on the same inventive concept, the present invention also constructs a three-phase grid-connected inverter generator controller, characterized by including a memory and a processor. The memory stores a computer program, and when executed by the processor, the computer program implements the steps of the method described in Example 1. The specific implementation process can be referred to the relevant description of the above method embodiment and will not be repeated here.

[0089] Example 4

[0090] Based on the same inventive concept, the present invention further provides a readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps of the method described in Example 1. The specific implementation process can be referred to the relevant description of the above method embodiment and will not be repeated here.

[0091] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0092] Terms containing ordinal numbers, such as "first" and "second," used in this specification may be used to describe various components, but these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component, without departing from the scope of the present invention.

[0093] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A three-phase grid-connected inverter wave control method, characterized in that: The method comprises: Obtaining a three-phase modulation wave signal output by a three-phase control loop of the inverter, and extracting a maximum value and a minimum value therefrom; The zero-sequence injection component of SVPWM wave control is calculated based on the extracted maximum and minimum values; The zero-sequence injection component of DPWM wave control is calculated based on the extracted maximum and minimum values; Based on the zero-sequence injection component of SVPWM wave control and the zero-sequence injection component of DPWM wave control, the optimal one is selected as the final zero-sequence injection component of the three-phase modulation wave; The three-phase modulation wave signals output by the three-phase control loop are respectively added with the final three-phase modulation wave zero-sequence injection component to obtain the final three-phase modulation wave signal; The method of selecting the optimal one of the zero-sequence injection component based on SVPWM wave generation control and the zero-sequence injection component based on DPWM wave generation control as the final zero-sequence injection component of the three-phase modulation wave specifically includes: When the absolute value of the zero-sequence injection component of the SVPWM wave control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final zero-sequence injection component of the three-phase modulation wave is equal to the zero-sequence injection component of the DPWM wave control; When the absolute value of the zero-sequence injection component of the SVPWM wave control is smaller than the absolute value of the zero-sequence injection component of the DPWM wave control, the final zero-sequence injection component of the three-phase modulation wave is equal to the zero-sequence injection component of the SVPWM wave control.

2. The three-phase grid-connected inverter wave control method according to claim 1, characterized in that: The calculating of the zero-sequence injection component for SVPWM wave generation control based on the extracted maximum and minimum values ​​specifically includes: adding the extracted maximum value to the extracted minimum value and multiplying the result by a preset proportional coefficient to obtain the zero-sequence injection component for SVPWM wave generation control.

3. The three-phase grid-connected inverter wave control method according to claim 1, characterized in that: The zero-sequence injection component of the DPWM wave control is calculated based on the extracted maximum and minimum values, specifically including: Calculate the difference between 1 and the extracted maximum value as the first candidate value; Calculate the difference between -1 and the extracted minimum value as the second candidate value; When the absolute value of the first candidate value is greater than or equal to the absolute value of the second candidate value, the zero-sequence injection component of the DPWM wave control is equal to the first candidate value; When the absolute value of the first candidate value is smaller than the absolute value of the second candidate value, the zero-sequence injection component of the DPWM wave control is equal to the second candidate value.

4. A three-phase grid-connected inverter wave control system, characterized in that: The system comprises: a maximum value extraction module configured to obtain the three-phase modulated wave signal output by the three-phase control loop of the inverter and extract the maximum value and the minimum value therefrom; A first zero-sequence injection component calculation module is configured to calculate the zero-sequence injection component of the SVPWM wave control based on the extracted maximum value and minimum value; A second zero-sequence injection component calculation module is configured to calculate the zero-sequence injection component of the DPWM wave control based on the extracted maximum value and minimum value; The zero-sequence injection component selection module is configured to select the optimal one as the final three-phase modulation wave zero-sequence injection component based on the zero-sequence injection component of the SVPWM wave control and the zero-sequence injection component of the DPWM wave control; The three-phase modulation wave signal output module is configured to add the final three-phase modulation wave zero-sequence injection component to the three-phase modulation wave signals output by the three-phase control loop to obtain the final three-phase modulation wave signal; The zero-sequence injection component selection module includes: The second absolute value comparator is used to ensure that, when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave generation control, the final zero-sequence injection component of the three-phase modulated wave is equal to the zero-sequence injection component of the DPWM wave generation control; and when the absolute value of the zero-sequence injection component of the SVPWM wave generation control is less than the absolute value of the zero-sequence injection component of the DPWM wave generation control, the final zero-sequence injection component of the three-phase modulated wave is equal to the zero-sequence injection component of the SVPWM wave generation control.

5. The three-phase grid-connected inverter wave control system according to claim 4, characterized in that: The first zero-sequence injection component calculation module includes: a first adder, configured to add the extracted maximum value to the extracted minimum value; A multiplier is connected to the first adder and is used to multiply the first adder by a preset proportional coefficient to obtain a zero-sequence injection component for SVPWM wave generation control.

6. The three-phase grid-connected inverter wave control system according to claim 4, characterized in that: The second zero-sequence injection component calculation module includes: a first subtractor, configured to calculate a difference between 1 and the extracted maximum value as a first candidate value; a second subtractor, configured to calculate a difference between -1 and the extracted minimum value as a second candidate value; The first absolute value comparator is configured to: when the absolute value of the first candidate value is greater than or equal to the absolute value of the second candidate value, ensure that the zero-sequence injection component of the SVPWM wave generation control is equal to the first candidate value; and when the absolute value of the first candidate value is less than the absolute value of the second candidate value, ensure that the zero-sequence injection component of the SVPWM wave generation control is equal to the second candidate value.

7. A three-phase grid-connected inverter wave controller, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 3 are implemented.

8. A readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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