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

Abstract

The invention discloses a three-phase grid-connected inverter wave sending method and system, a controller and a readable storage medium, and the method comprises the steps: obtaining a three-phase modulation wave signal outputted by a three-phase control loop of an inverter, and extracting a maximum value and a minimum value from the three-phase modulation wave signal; based on the extracted maximum value and minimum value, a zero-sequence injection component of SVPWM wave sending control is obtained through calculation; based on the extracted maximum value and minimum value, calculating to obtain a zero-sequence injection component controlled by the DPWM wave; selecting an optimal one of the zero-sequence injection components based on SVPWM (Space Vector Pulse Width Modulation) wave generation control and the zero-sequence injection components based on DPWM (Digital Pulse Width Modulation) wave generation control as a final three-phase modulation wave zero-sequence injection component; and the final three-phase modulation wave zero-sequence injection component is added to the three-phase modulation wave signal output by the three-phase control loop to obtain the final three-phase modulation wave signal, so that the switching loss is reduced, the equipment efficiency is improved, and meanwhile, the system stability is improved.

Description

Technical Field

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

[0002] Generally, three-phase grid-connected inverters use SPWM or SVPWM wave control, among which SVPWM square wave mode can improve DC voltage utilization compared with SPWM wave mode. Three-phase grid-connected inverters can also be controlled by DPWM wave mode, which can reduce switching losses and improve efficiency.

[0003] The three-phase grid-connected inverter adopts SPWM or SVPWM wave control, which controls the current sinusoidality and total harmonic distortion (THDI) of the current. However, when the current is near the maximum, the tube has to switch at a high frequency, so the switching loss is large and the efficiency is low, which affects the thermal performance of the equipment. In contrast, the three-phase grid-connected inverter adopts traditional DPWM wave control, and the tube does not operate near the maximum current, which effectively reduces the switching loss and improves the efficiency. However, at low modulation ratios, the modulation wave is not monotonous, and the LC filter LC resonance and the common mode voltage jump of the modulation wave crossing zero are generated in the low-frequency system, resulting in system instability. At the same time, the current sinusoidality and total harmonic distortion of the current are poor.

[0004] The above information disclosed in this Background section is included only for enhancement of understanding of the background of the present 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 view of the above-mentioned defects of the prior art.

[0006] The technical solution adopted by the present invention to solve the 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] Based on the extracted maximum and minimum values, the zero-sequence injection component of SVPWM wave control is calculated;

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

[0011] Based on the zero-sequence injection component of SVPWM wave control and the zero-sequence injection component of DPWM wave control, the best 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 to the extracted minimum value and multiplying it 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 SVPWM 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 SVPWM 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 SVPWM 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 zero-sequence injection component based on SVPWM wave generation control and the zero-sequence injection component based on DPWM wave generation control are 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 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 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 is configured to obtain a three-phase modulation wave signal output by a three-phase control loop of the inverter and extract a maximum value and a 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] A zero-sequence injection component selection module is configured to select the best 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;

[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 signal 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, used for calculating the difference between 1 and the extracted maximum value as a first candidate value;

[0033] A second subtractor, used for calculating the difference between -1 and the extracted minimum value as a second candidate value;

[0034] The first absolute value comparator is used to, 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 SVPWM wave control is equal to the first candidate value; when the absolute value of the first candidate value is less than the absolute value of the second candidate value, the zero-sequence injection component of the SVPWM wave 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 for, 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 three-phase modulation wave zero-sequence injection component 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 greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final three-phase modulation wave zero-sequence injection component is equal to the zero-sequence injection component of the SVPWM wave control.

[0037] In a third aspect, a three-phase grid-connected inverter wave generator controller is constructed, including 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 preceding 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 method combining SVPWM and DPWM, avoiding the problem that the conventional DPWM wave generation method controls the modulation wave at a low modulation ratio, the modulation wave is not monotonous, and the LC resonance of the LC filter and the common mode voltage jump of the modulation wave when the modulation wave crosses zero in the low-frequency system, resulting in system instability, and the current sinusoidality and total harmonic distortion of the current are poor. At the same time, it avoids the problem that the tube has to switch at a high frequency all the time when the SPWM and SVPWM wave generation methods are controlled near the maximum current, so the switching loss is large, the efficiency is low, and the thermal performance of the equipment is affected. 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 are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative 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 It is a principle 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 the composition of the three-phase grid-connected inverter wave generating system of the present invention. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the present invention are shown in the drawings. However, the present invention 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 invention more thorough and comprehensive. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0045] Embodiment 1

[0046] The three-phase modulation wave signals output by the three-phase control loop of the inverter are recorded as Va, Vb, and Vc respectively. 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 wave generation. For example, the generated modulation wave signals Va, Vb, and Vc are compared with a carrier signal of a fixed frequency. If the amplitude of the modulation wave is higher than the carrier signal, a high level is generated (the switching device of the inverter is turned on); otherwise, a low level is generated (the switching device of the inverter is turned off). The idea of ​​the present invention 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 wave generation control method of the present invention. The method combines SVPWM wave generation with DPWM wave generation, generates a new zero-sequence injection component, reduces switching loss, improves equipment efficiency, and improves system stability.

[0047] refer to Figure 1 A three-phase grid-connected inverter wave control method of the present invention is suitable for being executed by a controller of the inverter, and the method comprises:

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

[0049] The process of generating the three-phase modulation wave signals Va, Vb, and Vc output by the three-phase control loop is already existing and is not an improvement point of the present application. The three-phase control loop generally includes one or more feedbacks, and its purpose is to maintain the stability of the output voltage or current through closed-loop control. A typical control loop includes an outer loop control and an 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 invention executes this step S101 immediately after the three-phase control loop outputs the three-phase modulation wave signals Va, Vb, and Vc, as shown in FIG. Figure 2As shown, in the embodiment of the present invention, the maximum of the three-phase modulation wave signals Va, Vb, and Vc output from the three-phase control loop is taken and recorded as Vmax, and the minimum of the three of Va, Vb, and Vc is taken and recorded as Vmin.

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

[0051] refer to Figure 2 The zero-sequence injection component for SVPWM wave generation control is calculated based on the extracted maximum and minimum values, specifically comprising: adding the extracted maximum value Vmax to the extracted minimum value Vmin and then multiplying by a preset proportional coefficient K to obtain the zero-sequence injection component for SVPWM wave generation control, and this zero-sequence injection component is recorded as V0sv, that is, V0sv=K*(Vmax+Vmin).

[0052] The proportionality coefficient K here ranges from 0 to 1.

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

[0054] refer to Figure 2 , assuming that the zero-sequence injection component of the SVPWM wave control is recorded as V0dp, the zero-sequence injection component of the SVPWM wave control is calculated based on the extracted maximum and minimum values, specifically including:

[0055] Calculate the difference between 1 and the extracted maximum value Vmax (i.e. 1-Vmax), and use it as the first candidate value; It should be noted that Va, Vb, and Vc in the present invention have been normalized in the three-phase control loop (generally divided by the bus voltage U 母 Half of ) and the resulting value is less than or equal to 1;

[0056] Calculate the difference between -1 and the extracted minimum value Vmin (i.e. -1-Vmin), and use it as the second candidate value;

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

[0058] When the absolute value of the first candidate value (ie, |1-Vmax|) is smaller than the absolute value of the second candidate value (ie, |-1-Vmin|), the zero-sequence injection component V0dp of the SVPWM wave control is equal to the second candidate value.

[0059] S104: selecting the best 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 three-phase modulation wave zero-sequence injection component;

[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 of SVPWM wave control |V0sv| is greater than or equal to the absolute value of the zero-sequence injection component of DPWM wave control |V0dp|, the final three-phase modulation wave zero-sequence injection component V0fianl is equal to the zero-sequence injection component V0sv of 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, the drive signals can be generated according to the existing methods. For example, assuming that the inverter includes three-phase bridge arms in parallel, each phase bridge arm is composed of upper and lower switch tubes connected in series, and the drive signals of the upper and lower switch tubes are complementary. Then, Vafinal, Vbfinal, and Vcfinal can be compared with the carrier to obtain three PWM waveforms, which are recorded as PWMa, PWMb, and PWMc respectively. Then, PWMa, PWMb, and PWMc can be used to drive the upper tube of the three-phase bridge arm, and PWMa, PWMb, and PWMc can be flipped to drive the lower tube of the three-phase bridge arm.

[0069] This embodiment proposes a new zero-sequence component injection method for DPWM wave generation, which avoids the problem that the modulation wave is not monotonous when the traditional DPWM wave generation method is controlled at a low modulation ratio, and the LC resonance of the LC filter and the jump of the common mode voltage of the modulation wave when it passes through zero in the low-frequency system, resulting in system instability, and the current sinusoidality and THDi are poor. At the same time, it also avoids the problem that when the SPWM and SVPWM wave generation methods are controlled near the maximum current, the tube always has to switch at high frequency, so the switching loss is large, the efficiency is low, and the thermal performance of the equipment is affected. In short, this embodiment reduces the switching loss, improves the equipment efficiency, and improves the system stability.

[0070] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing related 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] Embodiment 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] The maximum value extraction module 201 is configured to obtain the three-phase modulation wave signal output by the three-phase control loop of the inverter and extract the maximum value and the 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 best 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 modulation wave signal output module 205 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.

[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, used for calculating the difference between 1 and the extracted maximum value as a first candidate value;

[0083] A second subtractor, used for calculating the difference between -1 and the extracted minimum value as a second candidate value;

[0084] The first absolute value comparator is used to, 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 SVPWM wave control is equal to the first candidate value; when the absolute value of the first candidate value is less than the absolute value of the second candidate value, the zero-sequence injection component of the SVPWM wave control is equal to the second candidate value.

[0085] Among them, 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 control is greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final three-phase modulation wave zero-sequence injection component 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 greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final three-phase modulation wave zero-sequence injection component is equal to the zero-sequence injection component of the SVPWM wave 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] Embodiment 3

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

[0089] Embodiment 4

[0090] Based on the same inventive concept, the present invention also constructs a readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method described in Embodiment 1. The specific implementation process can refer to the relevant description of the above method embodiment, which 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 the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0092] Terms including 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. The purpose of using these terms is only to distinguish one component from other components. For example, without departing from the scope of the present invention, the first component may be named as the second component, and similarly, the second component may also be named as the first component.

[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 modes, which are merely illustrative rather than 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 within the protection of 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; Based on the extracted maximum and minimum values, 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 zero-sequence injection component of SVPWM wave control and the zero-sequence injection component of DPWM wave control, the best 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.

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

4. The three-phase grid-connected inverter wave control method according to claim 1, characterized in that: The method of selecting the optimal one of the zero-sequence injection component based on the SVPWM wave generation control and the zero-sequence injection component based on the DPWM wave generation control as the final three-phase modulation wave zero-sequence injection component 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 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 SVPWM wave control.

5. A three-phase grid-connected inverter wave control system, characterized in that: The system comprises: A maximum value extraction module is configured to obtain a three-phase modulation wave signal output by a three-phase control loop of the inverter and extract a maximum value and a 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; A zero-sequence injection component selection module is configured to select the best 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; 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 signal output by the three-phase control loop to obtain the final three-phase modulation wave signal.

6. The three-phase grid-connected inverter wave control system according to claim 5, 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.

7. The three-phase grid-connected inverter wave control system according to claim 5, characterized in that: The second zero-sequence injection component calculation module includes: a first subtractor, used for calculating the difference between 1 and the extracted maximum value as a first candidate value; A second subtractor, used for calculating the difference between -1 and the extracted minimum value as a second candidate value; The first absolute value comparator is used to, 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 SVPWM wave control is equal to the first candidate value; when the absolute value of the first candidate value is less than the absolute value of the second candidate value, the zero-sequence injection component of the SVPWM wave control is equal to the second candidate value.

8. The three-phase grid-connected inverter wave control system according to claim 5, characterized in that: The zero-sequence injection component selection module comprises: The second absolute value comparator is used for, 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 three-phase modulation wave zero-sequence injection component 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 greater than or equal to the absolute value of the zero-sequence injection component of the DPWM wave control, the final three-phase modulation wave zero-sequence injection component is equal to the zero-sequence injection component of the SVPWM wave control.

9. A three-phase grid-connected inverter generator 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 4 are implemented.

10. 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 4 are implemented.

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