A grid-connected inverter control method and control system based on power-current hybrid synchronization

Abstract

This invention discloses a grid-connected inverter control method and control system based on power-current hybrid synchronization. The grid-connected inverter control method of this invention includes: acquiring the three-phase current of the inverter bridge arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor, and obtaining the instantaneous active power of the inverter system; obtaining the hybrid synchronization control output phase using a power synchronization loop and a current synchronization loop; obtaining the first control signal of the inverter using capacitor voltage control; performing a Park inverse transform on the first control signal based on the hybrid synchronization control output phase to obtain a second control signal in a three-phase stationary coordinate system; and performing pulse width modulation on the second control signal to generate switching signals for the power devices in the inverter. This invention enables the grid-connected inverter to operate stably under a wide range of grid strength conditions.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically, to a grid-connected inverter control method and control system based on power-current hybrid synchronization. Background Technology

[0002] With the rapid advancement of new energy technologies, the installed capacity of renewable energy sources such as wind power and photovoltaics continues to increase, and a large number of new energy units are connected to the power grid via long-distance lines through grid-connected inverters. Wind and solar energy resources exhibit significant diurnal periodicity and volatility, causing the output power of new energy power plants to vary continuously over a wide range from zero to rated power on an hourly timescale. This output characteristic results in the equivalent short-circuit ratio (SCR) at the grid connection point also exhibiting slowly varying and wide-range dynamic characteristics throughout the day, posing a severe challenge to the stable operation of grid-connected inverters. This requires the control system of the grid-connected inverter to have the ability to maintain stable operation under a wide range of grid strength conditions. However, existing control strategies suffer from insufficient stability when facing continuously changing grid conditions.

[0003] Therefore, improving the steady-state stability of grid-connected inverters under different operating conditions of strong and weak power grids has become a critical issue that urgently needs to be addressed. Existing technologies have yielded relevant research; for example, the paper "Adaptive Grid-Connecting Control of Converters and Mechanism Analysis for Improving Oscillation Stability" designs a hybrid synchronization control based on voltage synchronization and power synchronization loops. However, the proposed control strategy only achieves stable operation within the SCR range of 1 to 5, failing to meet the stability requirements under a wide range of SCR variations.

[0004] In summary, existing grid-connected inverter technologies still suffer from insufficient stability under a wide range of grid strength. Although some methods can maintain stability within a limited SCR range, they still face the risk of oscillation and instability when the SCR varies widely. Therefore, to achieve stable operation of grid-connected inverters under a wide range of grid strength, it is urgent to propose a new grid-connected inverter control method and control system. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a grid-connected inverter control method and control system based on power-current hybrid synchronization, so as to achieve stable operation of the grid-connected inverter under a wide range of grid strength.

[0006] To address the aforementioned problems, in a first aspect, the present invention provides a grid-connected inverter control method based on power-current hybrid synchronization, comprising:

[0007] The system collects the three-phase current of the inverter arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor, and obtains the instantaneous active power output of the inverter system. The three-phase voltages of the inverter-side filter capacitors and the three-phase currents of the inverter bridge arm inductors are respectively subjected to Park transformation to obtain the synchronous rotating coordinate system. d Axis voltage variable q Axis voltage variable d shaft current variables and q Axis current variable; Based on the deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using the power synchronization loop and the current synchronization loop; based on d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is used to obtain the first control signal of the inverter by controlling the capacitor voltage. Based on the hybrid synchronous control output phase, the first control signal is subjected to Park inverse transformation to obtain the second control signal in the three-phase stationary coordinate system; The second control signal is pulse-width modulated to generate switching signals for the power devices in the inverter.

[0008] In some embodiments, obtaining the instantaneous active power output by the inverter system includes: Based on formula Obtain the instantaneous active power output of the inverter system, where P is the instantaneous active power output of the inverter system. , , The three-phase voltage of the inverter-side filter capacitor is... , , This represents the three-phase current of the grid-side inductor.

[0009] In some embodiments, the deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using a power synchronization loop and a current synchronization loop, including: Based on the deviation between the active power command value and the instantaneous active power, the first output phase of power synchronization control is obtained using the power synchronization loop; based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is obtained by using the current synchronization loop to obtain the second output phase of the current synchronization control; The hybrid synchronization control output phase is obtained based on the first output phase and the second output phase.

[0010] In some embodiments, obtaining the first output phase of power synchronization control using a power synchronization loop based on the deviation between the active power command value and the instantaneous active power includes: Based on formula Obtain the first output phase of the power synchronization control, where... This is the first output phase. This is the proportional adjustment coefficient of the power synchronization loop. The active power command value is... The instantaneous active power, For the Laplace operator.

[0011] In some embodiments, based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is obtained by using a current synchronization loop to obtain the second output phase of the current synchronization control, including: Based on formula Obtain the second output phase of the current synchronization control, where, This is the second output phase. For the q Virtual reference value for shaft current variable. For the q shaft current variable, This is the proportional adjustment coefficient of the current synchronization loop ISC. This is the bandwidth of the low-pass filter in the current synchronization loop ISC. For the Laplace operator.

[0012] In some embodiments, obtaining the hybrid synchronization control output phase based on the first output phase and the second output phase includes: Based on formula Obtain the hybrid synchronization control output phase, wherein, This is the first output phase. This is the second output phase. As the reference phase, based on the formula Obtain, among which, The system's rated angular frequency,s For the Laplace operator.

[0013] In some embodiments, the based d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is obtained by using capacitor voltage control to acquire the first control signal of the inverter, including: Based on formula

[0014] Obtain the first control signal respectively d Axial components and q Axial components, where, , These are the first control signals. d Axial components and q Axial components, F CVC , F ACC These are the transfer functions of the first PI controller and the second PI controller, respectively, for capacitor voltage control. , The respective d Shaft voltage reference value and the above q Shaft voltage reference value, , The respective d shaft voltage variables and the q Axis voltage variable, The system's rated angular frequency, The capacitance value is the value of the inverter-side filter capacitor. The inductance value of the grid-side inductor. The respective q shaft current variables and the d Axis current variable; in, , This is the proportional adjustment coefficient of the first PI controller. This is the integral adjustment coefficient of the first PI controller. s For the Laplace operator; , This is the proportional adjustment coefficient of the second PI controller. This is the integral adjustment coefficient of the second PI controller.

[0015] Secondly, the present invention provides a grid-connected inverter control system based on power-current hybrid synchronization, comprising: The acquisition module is configured to acquire the three-phase current of the inverter arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor of the inverter system. The power acquisition module is configured to acquire the instantaneous active power output by the inverter system based on the data acquired by the acquisition module; The Park transformation module is configured to perform Park transformation on the three-phase voltage of the inverter-side filter capacitor and the three-phase current of the inverter arm inductor to obtain the synchronous rotating coordinate system. d Axis voltage variable q Axis voltage variable d shaft current variables and q Axis current variable; A hybrid synchronous control module is configured to base its operation on the deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using the power synchronization loop and the current synchronization loop; The control signal acquisition module is configured to be based on d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is used to obtain the first control signal of the inverter by controlling the capacitor voltage. The Park inverse transform module is configured to perform a Park inverse transform on the first control signal based on the hybrid synchronous control output phase to obtain a second control signal in a three-phase stationary coordinate system. A pulse width modulation module is configured to perform pulse width modulation on the second control signal to generate switching signals for the power devices in the inverter.

[0016] In some embodiments, the hybrid synchronization control module includes: A power synchronization loop is configured to obtain the first output phase of power synchronization control based on the deviation between the active power command value and the instantaneous active power. A current synchronization loop, which is configured to be based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the second output phase of the current synchronization control; A hybrid synchronization control output phase acquisition module is configured to acquire the hybrid synchronization control output phase based on the first output phase and the second output phase.

[0017] In some embodiments, the inverter bridge arm inductor The inverter-side filter capacitor is 3mH. The grid-side inductance is 10mF. It is 33mH.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The grid-connected inverter control method based on power-current hybrid synchronization provided by this invention introduces current synchronization to form power-current hybrid synchronization control, increases the equivalent damping of the inverter system, improves the frequency support characteristics of the grid-connected inverter, and can ensure that the system maintains stable operation over a wider SCR range from strong grid to weak grid. This fundamentally solves the stability problem when the output fluctuation of new energy power plants causes wide changes in the equivalent SCR at the grid connection point. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating a grid-connected inverter control method based on power-current hybrid synchronization provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a three-phase LC grid-connected inverter and some control modules according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a hybrid synchronization control module according to an embodiment of the present invention; Figure 4 The waveforms of the grid connection point voltage and inverter output current before and after applying the grid-connected inverter control method provided by this invention are shown under the condition that the grid short-circuit ratio is 10 (strong grid). Figure 5 The waveforms of the grid connection point voltage and inverter output current before and after applying the grid-connected inverter control method provided by this invention are shown under the condition that the grid short-circuit ratio is 1 (weak grid). Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the grid-connected inverter control method and control system based on power-current hybrid synchronization proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise scales, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, scales, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in scale, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0021] As described in the background section, existing grid-connected inverters still suffer from insufficient stability under a wide range of grid strength. While some methods can maintain stability within a limited SCR range, they still face the risk of oscillation and instability when the SCR varies widely. This embodiment aims to provide a grid-connected inverter control method based on power-current hybrid synchronization to achieve stable operation of the grid-connected inverter under a wide range of grid strength.

[0022] Specifically, please refer to Figure 1 and Figure 2 , Figure 1 This is a flowchart illustrating the grid-connected inverter control method based on power-current hybrid synchronization provided in this embodiment. Figure 2 This is a structural diagram of the three-phase LC grid-connected inverter and some control modules provided in this embodiment. Please refer to it. Figure 1 and Figure 2 The control method includes: Step S1: Collect the inverter arm inductance of the inverter system. Three-phase current , , Inverter-side filter capacitor Three-phase voltage , , and grid-side inductors Three-phase current , , And obtain the instantaneous active power P output by the inverter system.

[0023] Specifically, in this embodiment, the inverter bridge arm inductor The inverter-side filter capacitor is 3mH. The grid-side inductance is 10mF. The value is 33mH. It should be noted that the control method provided in this embodiment does not rely on a fixed set of parameters. The specific values ​​given are only one feasible embodiment for verifying the present invention. In other embodiments, the inverter bridge arm inductance... Inverter-side filter capacitor and grid-side inductors Other values ​​can be selected based on specific system design requirements, power grid conditions, and performance indicators; this embodiment does not impose specific limitations.

[0024] Step S2: Convert the three-phase voltage of the inverter-side filter capacitor. , , Three-phase current of inverter bridge arm inductor , , Perform Park transformations separately to obtain the coordinates in the synchronous rotating coordinate system. d Axis voltage variable , q Axis voltage variable , d Axis current variable as well as q Axis current variable .

[0025] Step S3: Based on the active power command value The deviation from the instantaneous active power P, and q Virtual reference value of shaft current variable With the q Axis current variable The deviation is addressed by using the power synchronization loop (PSC) and the current synchronization loop (ISC) to obtain the hybrid synchronization control output phase. .

[0026] It should be noted that the active power command value Based on system design requirements, 3500W is used in this embodiment. In other embodiments, the active power command value is... Other values ​​can be selected based on system design requirements; this embodiment does not impose specific limitations. Similarly, the... q Virtual reference value of shaft current variable This is also based on system design requirements, and this embodiment does not impose any specific limitations.

[0027] Step S4: Based on d Axis voltage variable , q Axis voltage variable , d Axis current variable , q Axis current variable , d Shaft voltage reference value and q Shaft voltage reference value The first control signal of the inverter is obtained by using capacitor voltage control. , .

[0028] In this embodiment, the d Shaft voltage reference value Take 70.7V, the q Shaft voltage reference value In other embodiments, the value is 0. d Shaft voltage reference value and q Shaft voltage reference value Other values ​​can be selected according to the system design requirements; this embodiment does not impose specific limitations.

[0029] Step S5: Output phase based on the hybrid synchronization control For the first control signal , Perform inverse Park transform to obtain the second control signal in the three-phase stationary coordinate system. , , .

[0030] Step S6: For the second control signal , , Pulse width modulation is performed to generate switching signals for the power devices in the inverter, which are then passed through a drive circuit to control the power devices to turn on and off.

[0031] The grid-connected inverter control method based on power-current hybrid synchronization provided in this embodiment introduces current synchronization to form power-current hybrid synchronization control, which increases the equivalent damping of the inverter system and improves the frequency support characteristics of the grid-connected inverter. This ensures that the system maintains stable operation over a wider SCR range from strong grid to weak grid, fundamentally solving the stability problem when the output fluctuation of new energy power plants causes wide changes in the equivalent SCR at the grid connection point.

[0032] In step S1, obtaining the instantaneous active power P output by the inverter system includes: Based on formula Obtain the instantaneous active power P output by the inverter system, where, , , The three-phase voltage of the inverter-side filter capacitor is... , , This represents the three-phase current of the grid-side inductor.

[0033] Specifically, please refer to Figure 3 , Figure 3 This is a schematic diagram of the hybrid synchronization control module provided in this embodiment. In step S3, the step based on the active power command value... The deviation from the instantaneous active power P, and q Virtual reference value of shaft current variable With the q Axis current variable The deviation is addressed by using the power synchronization loop (PSC) and the current synchronization loop (ISC) to obtain the hybrid synchronization control output phase. ,include: Step S31: Based on the active power command value The deviation from the instantaneous active power P is used to obtain the first output phase of power synchronization control via the power synchronization loop PSC. ; Step S32: Based on q Virtual reference value of shaft current variable With the q Axis current variable The deviation is addressed by using the current synchronization loop ISC to obtain the second output phase of the current synchronization control. ; Step S33: Based on the first output phase and the second output phase Obtain the hybrid synchronization control output phase .

[0034] For details, please refer to [link / reference]. Figure 3 In step S31, the active power command value is used as the basis for the operation. The deviation from the instantaneous active power P is used to obtain the first output phase of power synchronization control via the power synchronization loop PSC. ,include: Based on formula Obtain the first output phase of power synchronization control ,in, This is the first output phase. This is the proportional adjustment coefficient of the power synchronization loop PSC. The active power command value is... The instantaneous active power, This is the Laplace operator. Specifically, in this embodiment, the proportional adjustment coefficient of the power synchronization loop... The value is set to 0.0036. In other embodiments, other parameters of the power synchronization loop (PSC) can be selected according to the system design requirements. This embodiment does not impose specific limitations.

[0035] For details, please refer to [link / reference]. Figure 3 In step S32, based on q Virtual reference value of shaft current variable With the q Axis current variable The deviation is addressed by using the current synchronization loop ISC to obtain the second output phase of the current synchronization control. ,include: Based on formula Obtain the second output phase of the current synchronization control, where, This is the second output phase. For the q Virtual reference value for shaft current variable. For the q shaft current variable, This is the proportional adjustment coefficient of the current synchronization loop ISC. This is the bandwidth of the low-pass filter in the current synchronization loop ISC. This is the Laplace operator. Specifically, in this embodiment, the proportional adjustment coefficient of the current synchronization loop ISC is... Take 2.6155, the low-pass filter bandwidth of the current synchronization loop ISC. The value is 6.2832. In other embodiments, the current synchronization loop ISC with other parameters can be selected according to the system design requirements. This embodiment does not impose specific limitations.

[0036] For details, please refer to [link / reference]. Figure 3 In step S33, based on the first output phase and the second output phase Obtain the hybrid synchronization control output phase ,include: Based on formula Obtain the hybrid synchronization control output phase ,in, This is the first output phase. This is the second output phase. As the reference phase, based on the formula Obtain, among which, The system's rated angular frequency is taken as 314.1592 rad / s in this embodiment. s For the Laplace operator.

[0037] In step S4, the basis d Axis voltage variable ,q Axis voltage variable , d Axis current variable , q Axis current variable , d Shaft voltage reference value and q Shaft voltage reference value The first control signal of the inverter is obtained by using capacitor voltage control. , ,include: Based on formula

[0038] Obtain the first control signal respectively d Axial components and q Axial components ,in, F CVC , F ACC These are the transfer functions of the first PI controller and the second PI controller, respectively, for capacitor voltage control. This is the system's rated angular frequency; in, , This is the proportional adjustment coefficient of the first PI controller. This is the integral adjustment coefficient of the first PI controller. s For the Laplace operator; , This is the proportional adjustment coefficient of the second PI controller. This is the integral adjustment coefficient of the second PI controller.

[0039] Specifically, in this embodiment, the proportional control coefficient of the first PI controller The integral adjustment coefficient of the first PI controller is set to 0.08. Take 80 as the proportional control coefficient of the second PI controller. Take 12.5 as the integral adjustment coefficient of the second PI controller. In other embodiments, the first PI controller and the second PI controller with other parameters can be selected according to the system design requirements. This embodiment does not make specific limitations.

[0040] Please see Figure 4 , Figure 4 The graphs show the waveforms of the grid connection point voltage and inverter output current before and after applying the grid-connected inverter control method provided in this embodiment, under the condition of a grid short-circuit ratio of 10 (strong grid). Figure 4It is evident that, after adopting the grid-connected inverter control method of this embodiment, the inverter system under a strong power grid can operate stably.

[0041] Please see Figure 5 , Figure 5 The graphs show the waveforms of the grid connection point voltage and inverter output current before and after applying the grid-connected inverter control method provided in this embodiment, under the condition of a grid short-circuit ratio of 1 (weak grid). Figure 5 It is evident that, by adopting the grid-connected inverter control method of this embodiment, the inverter system under a weak power grid can operate stably.

[0042] Based on the same inventive concept, this embodiment also provides a grid-connected inverter control system based on power-current hybrid synchronization, the control system comprising: The acquisition module is configured to acquire the three-phase current of the inverter arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor of the inverter system. The power acquisition module is configured to acquire the instantaneous active power output by the inverter system based on the data acquired by the acquisition module; The Park transformation module is configured to perform Park transformation on the three-phase voltage of the inverter-side filter capacitor and the three-phase current of the inverter arm inductor to obtain the synchronous rotating coordinate system. d Axis voltage variable q Axis voltage variable d shaft current variables and q Axis current variable; A hybrid synchronous control module is configured to base its operation on the deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using the power synchronization loop and the current synchronization loop; The control signal acquisition module is configured to be based on d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is used to obtain the first control signal of the inverter by controlling the capacitor voltage. The Park inverse transform module is configured to perform a Park inverse transform on the first control signal based on the hybrid synchronous control output phase to obtain a second control signal in a three-phase stationary coordinate system. A pulse width modulation module is configured to perform pulse width modulation on the second control signal to generate switching signals for the power devices in the inverter.

[0043] In some embodiments, the hybrid synchronization control module includes: A power synchronization loop is configured to obtain the first output phase of power synchronization control based on the deviation between the active power command value and the instantaneous active power. A current synchronization loop, which is configured to be based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the second output phase of the current synchronization control; A hybrid synchronization control output phase acquisition module is configured to acquire the hybrid synchronization control output phase based on the first output phase and the second output phase.

[0044] In summary, the grid-connected inverter control system based on power-current hybrid synchronization provided in this embodiment introduces a current synchronization loop to form a power-current hybrid synchronization control architecture, increases the equivalent damping of the inverter system, improves the frequency support characteristics of the grid-connected inverter, and can ensure that the system maintains stable operation over a wider SCR range from strong grid to weak grid.

[0045] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0046] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0047] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A grid-connected inverter control method based on power-current hybrid synchronization, characterized in that, include: The system collects the three-phase current of the inverter arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor, and obtains the instantaneous active power output of the inverter system. The three-phase voltage of the inverter side filter capacitor and the three-phase current of the inverter bridge arm inductor are respectively subjected to Park transformation to obtain d a d-axis voltage variable, q a q-axis voltage variable, d a d-axis current variable, and q a q-axis current variable. based on a deviation of the active instruction value from the instantaneous active power, and q a deviation of the shaft current variable from the q a mixed synchronization control output phase is obtained using a power synchronization loop and a current synchronization loop; based on d an axle voltage variable, q an axle voltage variable, d an axle current variable, q an axle current variable, d an axle voltage reference value, and q an axle voltage reference value, a first control signal for the inverter is obtained using a capacitor voltage control. Based on the hybrid synchronous control output phase, the first control signal is subjected to Park inverse transformation to obtain the second control signal in the three-phase stationary coordinate system; The second control signal is pulse-width modulated to generate switching signals for the power devices in the inverter.

2. The grid-connected inverter control method of claim 1, wherein, The acquisition of the instantaneous active power output by the inverter system includes: Based on the formula acquiring the instantaneous active power output by the inverter system, wherein P is the instantaneous active power output by the inverter system, , , is the three-phase voltage of the inverter-side filter capacitor, , , is the three-phase current of the grid-side inductor.

3. The grid-connected inverter control method as described in claim 1, characterized in that, The deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using a power synchronization loop and a current synchronization loop, including: Based on the deviation between the active power command value and the instantaneous active power, the first output phase of power synchronization control is obtained using the power synchronization loop; based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is obtained by using the current synchronization loop to obtain the second output phase of the current synchronization control; The hybrid synchronization control output phase is obtained based on the first output phase and the second output phase.

4. The grid-connected inverter control method as described in claim 3, characterized in that, The step of obtaining the first output phase of power synchronization control using a power synchronization loop based on the deviation between the active power command value and the instantaneous active power includes: Based on formula Obtain the first output phase of the power synchronization control, where... This is the first output phase. This is the proportional adjustment coefficient of the power synchronization loop. The active power command value is... The instantaneous active power, For the Laplace operator.

5. The grid-connected inverter control method as described in claim 3, characterized in that, The basis q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is obtained by using a current synchronization loop to obtain the second output phase of the current synchronization control, including: Based on formula Obtain the second output phase of the current synchronization control, where, This is the second output phase. For the q Virtual reference value for shaft current variable. For the q shaft current variable, This is the proportional adjustment coefficient of the current synchronization loop ISC. This is the bandwidth of the low-pass filter in the current synchronization loop ISC. For the Laplace operator.

6. The grid-connected inverter control method as described in claim 3, characterized in that, The step of obtaining the hybrid synchronization control output phase based on the first output phase and the second output phase includes: Based on formula Obtain the hybrid synchronization control output phase, wherein, This is the first output phase. This is the second output phase. As the reference phase, based on the formula Obtain, among which, The system's rated angular frequency, s For the Laplace operator.

7. The grid-connected inverter control method as described in claim 1, characterized in that, The basis d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is obtained by using capacitor voltage control to acquire the first control signal of the inverter, including: Based on formula Obtain the first control signal respectively d Axial components and q Axial components, where, , These are the first control signals. d Axial components and q Axial components, F CVC , F ACC These are the transfer functions of the first PI controller and the second PI controller, respectively, for capacitor voltage control. , The respective d Shaft voltage reference value and the above q Shaft voltage reference value, , The respective d shaft voltage variables and the q Axis voltage variable, The system's rated angular frequency, The capacitance value is the value of the inverter-side filter capacitor. The inductance value of the grid-side inductor. The respective q shaft current variables and the d Axis current variable; in, , This is the proportional adjustment coefficient of the first PI controller. This is the integral adjustment coefficient of the first PI controller. s For the Laplace operator; , This is the proportional adjustment coefficient of the second PI controller. This is the integral adjustment coefficient of the second PI controller.

8. A grid-connected inverter control system based on power-current hybrid synchronization, characterized in that, include: The acquisition module is configured to acquire the three-phase current of the inverter arm inductor, the three-phase voltage of the inverter-side filter capacitor, and the three-phase current of the grid-side inductor of the inverter system. The power acquisition module is configured to acquire the instantaneous active power output by the inverter system based on the data acquired by the acquisition module; The Park transformation module is configured to perform Park transformation on the three-phase voltage of the inverter-side filter capacitor and the three-phase current of the inverter arm inductor to obtain the synchronous rotating coordinate system. d Axis voltage variable q Axis voltage variable d shaft current variables and q Axis current variable; A hybrid synchronous control module is configured to base its operation on the deviation between the active power command value and the instantaneous active power, and q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the hybrid synchronous control output phase using the power synchronization loop and the current synchronization loop; The control signal acquisition module is configured to be based on d Axis voltage variable q Axis voltage variable d shaft current variable, q shaft current variable, d Shaft voltage reference value and q The shaft voltage reference value is used to obtain the first control signal of the inverter by controlling the capacitor voltage. The Park inverse transform module is configured to perform a Park inverse transform on the first control signal based on the hybrid synchronous control output phase to obtain a second control signal in a three-phase stationary coordinate system. A pulse width modulation module is configured to perform pulse width modulation on the second control signal to generate switching signals for the power devices in the inverter.

9. The grid-connected inverter control system as described in claim 8, characterized in that, The hybrid synchronization control module includes: A power synchronization loop is configured to obtain the first output phase of power synchronization control based on the deviation between the active power command value and the instantaneous active power. A current synchronization loop, which is configured to be based on q The virtual reference value of the shaft current variable and the above q The deviation of the shaft current variable is used to obtain the second output phase of the current synchronization control; A hybrid synchronization control output phase acquisition module is configured to acquire the hybrid synchronization control output phase based on the first output phase and the second output phase.

10. The grid-connected inverter control system as described in claim 8, characterized in that, The inverter bridge arm inductor The inverter-side filter capacitor is 3mH. The grid-side inductance is 10mF. It is 33mH.

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