Control method and device of inverter, computing device and machine readable storage medium

Abstract

This application discloses a control method, apparatus, computing device, and machine-readable storage medium for an inverter, belonging to the field of photovoltaic grid connection. The inverter control method includes: determining a first projection component of the grid-connected current on the d-axis and a second projection component on the q-axis based on the output phase angle of the phase-locked loop; obtaining a first current reference value component and a second current reference value component; obtaining a first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and a first control parameter; obtaining a suppression feedback signal based on the voltage component of the connection point voltage on the q-axis and the disturbance transfer function of the phase-locked loop; obtaining a second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and a second control parameter; and controlling the switching transistor according to the first modulation signal and the second modulation signal.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic grid connection, and more specifically to a control method, apparatus, computing device, and machine-readable storage medium for an inverter. Background Technology

[0002] With the rapid development of new energy technologies, the proportion of distributed photovoltaic (PV) power grid connections is constantly increasing, making the trend of power grid electrification increasingly significant. Grid-connected inverters have the advantages of high controllability and high efficiency. PV power is converted from direct current (DC) to alternating current (AC) through grid-connected inverters, and then the converted AC power is fed into the grid. The control loop of grid-connected inverters has a wide time scale, and the interaction between the inverter and grid impedance affects the stability of the grid-connected inverter.

[0003] With the integration of numerous distributed photovoltaic (PV) systems into the grid, the impedance interaction between the PV systems and the grid can easily lead to broadband oscillations in the grid-connected system, thereby threatening the security of the grid system. To suppress these broadband oscillations, the control loop structure of the grid-connected inverter is typically altered or additional auxiliary control loops are added. This results in an overly complex control structure for the grid-connected inverter, making it excessively difficult to control. Furthermore, adding additional auxiliary control loops requires additional sensors to sample additional state variables, further complicating the control structure and making grid-connected inverter control even more challenging. Summary of the Invention

[0004] The purpose of this invention is to provide a control method, apparatus, computing device, and machine-readable storage medium for an inverter, so as to solve the problem of overly complex control structures for inverters.

[0005] To achieve the above objectives, the first aspect of this application provides a control method for an inverter. The inverter includes a switching transistor, a phase-locked loop (PLL), a d-axis current regulator, and a q-axis current regulator. The switching transistor is connected to the input terminals of the d-axis and q-axis current regulators respectively via the PLL. The output terminals of both the d-axis and q-axis current regulators are connected to the switching transistor. The inverter is connected to the power grid via a connection point. The control method for the inverter includes:

[0006] Based on the output phase angle of the phase-locked loop, determine the first projection component of the grid-connected current on the d-axis and the second projection component on the q-axis;

[0007] Obtain the first current reference value component and the second current reference value component, wherein the first current reference value is the component of the grid-connected current reference value on the d-axis, and the second current reference value is the component of the grid-connected current reference value on the q-axis.

[0008] Acquire a first modulation signal output by the d-axis current regulator based on a first projection component, a first current reference value, and a first control parameter, wherein the first control parameter is the control parameter of the d-axis current regulator;

[0009] Based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop, the suppression feedback signal is obtained;

[0010] The second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameter is obtained. The second control parameter is the control parameter of the q-axis current regulator, and the first control parameter and the second control parameter are asymmetric control parameters.

[0011] The switching transistor is controlled according to the first modulation signal and the second modulation signal.

[0012] The beneficial effects of this application are as follows:

[0013] Without altering the inverter's control loop structure or adding additional auxiliary control loops, asymmetric control parameters for the d-axis and q-axis enhance the system's oscillation suppression capability, preventing the inverter's control structure from becoming overly complex. Furthermore, the q-axis employs an asymmetric design that introduces a suppression feedback signal to offset the negative impact of the phase-locked loop on the inverter's wideband oscillations, further improving the system's oscillation suppression capability while simplifying the inverter's control structure.

[0014] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0016] Figure 1 An example diagram of the control structure of the inverter provided in an embodiment of this application is shown;

[0017] Figure 2 A flowchart of the inverter control method provided in an embodiment of this application is shown;

[0018] Figure 3 A schematic diagram of the control structure of the phase-locked loop provided in an embodiment of this application is shown;

[0019] Figure 4 A schematic diagram of the d-axis current control inner loop provided in an embodiment of this application is shown;

[0020] Figure 5A schematic diagram of the q-axis current control inner loop provided in an embodiment of this application is shown;

[0021] Figure 6 The transfer function model of the inverter provided in the embodiment of this application is shown;

[0022] Figure 7 An example diagram of the characteristic value curve of the grid impedance of 32mH provided in the embodiments of this application is shown;

[0023] Figure 8 An example diagram of the characteristic value curve of the grid impedance of 35mH provided in the embodiments of this application is shown;

[0024] Figure 9 This paper presents an example diagram of the grid-connected current waveform with a grid impedance of 32mH, provided in an embodiment of this application.

[0025] Figure 10 This paper presents an example diagram of the grid-connected current waveform with a grid impedance of 35mH, provided in an embodiment of this application.

[0026] Figure 11 A schematic diagram of the control device for the inverter provided in an embodiment of this application is shown. Detailed Implementation

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the present invention.

[0028] The components of the embodiments of the invention described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0030] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0031] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0032] Example 1

[0033] Please see Figure 1 , Figure 1 An example diagram of the control structure of the inverter provided in an embodiment of this application is shown.

[0034] The inverter includes switching transistors, a phase-locked loop (PLL), a d-axis current regulator, and a q-axis current regulator. The switching transistors are connected to the input terminals of the d-axis and q-axis current regulators respectively via the PLL. The output terminals of both the d-axis and q-axis current regulators are connected to the switching transistors. The inverter is connected to the power grid through a connection point. The control methods for the inverter include:

[0035] In this embodiment, the inverter also includes other components, which are set according to actual needs and are not limited here. For ease of understanding, the other components in this embodiment include DC-side capacitors, first filter inductors, second filter inductors, and filter capacitors, etc., and are not limited here. The switching transistor is the inverter bridge of the inverter, I. ds C is the current source for the inverter. dc U is the DC-side capacitor of the inverter. dc u is the DC bus voltage of the inverter. inv Where i is the output voltage of the inverter's switching transistor, i1 is the inductor current on the inverter side, L1 is the first filter inductor, L2 is the second filter inductor, and C is the current of the inverter's switching transistor. f For filter capacitors, L1 and C f And L2 form an LCL (Inductor-Capacitor-Inductor) filter, R d It is a passive damping resistor.

[0036] The inverter is connected to the grid through the access point, i2 is the inverter's output grid-connected current, Z g U is the power grid impedance. pcc U is the voltage at point PCC. g The voltage is the grid voltage. The PPC point is a point in the power system where multiple users or devices are connected together; in this embodiment, it is the access point of the phase-locked loop. dcref u is the given value of the DC bus voltage.dc G is the actual voltage across the DC-side capacitor. v (s) represents the control parameters of the inner loop PI controller; I 2dref The d-axis reference value component of the grid-connected current reference value; I 2qref For the grid-connected current reference value q-axis reference value component; i 2d i 2q These are the projected components of the grid-connected current on the d and q axes, respectively; G id (s) is the first control parameter of the d-axis current regulator, G iq (s) is the second control parameter of the q-axis current regulator; G PLL (s) represents the small-signal perturbation transfer function model of the phase-locked loop; I 2d0 The preset conversion factor is the steady-state value of the grid-connected current on the d-axis; K is the feedback gain; G is the feedback gain. g,c V represents the equivalent transformation coefficient between the q-axis voltage in the grid's dq coordinate system and the q-axis voltage in the controller's dq coordinate system. Md V is the first modulation signal output by the d-axis current regulator. Mq K is the second modulation signal output by the q-axis current regulator. PWM θ is the pulse width modulation gain; θ is the output phase angle of the phase-locked loop (PLL).

[0037] Please see Figure 2 , Figure 2 A flowchart of the control method for an inverter provided in an embodiment of this application is shown.

[0038] S110, based on the output phase angle of the phase-locked loop, determine the first projection component of the grid-connected current on the d-axis and the second projection component on the q-axis.

[0039] Grid-connected current refers to the output current of the inverter connected to the power grid after the inverter is connected. Grid-connected current is typically represented using an ABC three-phase coordinate system, where A, B, and C represent three phases with a phase difference of 120 degrees, indicating the phase and amplitude of physical quantities such as current and voltage. The dq coordinate system, also known as a rotating coordinate system, has a d-axis (direct axis) aligned with the direction of the rotating magnetic field, and a q-axis (quadrature axis) perpendicular to the d-axis, typically used to represent the portion perpendicular to the magnetic field.

[0040] Based on the output phase angle of the phase-locked loop (PLL), the first projected component of the grid-connected current on the d-axis and the second projected component on the q-axis are determined. The three-phase coordinates (A, B, C) of the grid-connected current are converted into dq coordinates. The output angle of the PLL is used as the reference angle for the dp-axis. The grid-connected current is decomposed along the dp-axis, converting the three-phase signal into a rotating DC coordinate system, thereby simplifying the complexity of analysis and control.

[0041] S120, obtain the first current reference value component and the second current reference value component, wherein the first current reference value is the component of the grid-connected current reference value on the d-axis, and the second current reference value is the component of the grid-connected current reference value on the q-axis.

[0042] The current reference value refers to the current value used to control the target in an electrical system. The grid-connected current reference value is decomposed along the d-axis to obtain a first current reference value component and a second current reference value component. The first current reference value is the d-axis component of the grid-connected current reference value, and the second current reference value is the q-axis component of the grid-connected current reference value.

[0043] In embodiments of this application, obtaining the first current reference value component and the second current reference value component includes:

[0044] Construct the equation relationship between the DC side and AC side of the inverter;

[0045] Construct a first small-signal model between the voltage outer loop and the current inner loop reference values ​​of the inverter;

[0046] Based on the equations and the first small-signal model, the second small-signal model of the current inner loop is obtained;

[0047] Based on the second small-signal model, the first current reference value component and the second current reference value component are obtained.

[0048] The small-signal model is a linear approximation model used to describe and analyze nonlinear systems near a specific operating point. When signal variations are small, the small-signal model simplifies the analysis of complex nonlinear systems. For ease of understanding, this embodiment uses the small-signal model for calculations, constructing an equation between the DC and AC sides of the inverter, and converting this equation into matrix form:

[0049]

[0050]

[0051] Among them, U dc I is the DC-side voltage of the inverter. ds U is the current source for the inverter. cmi is the AC side voltage of the inverter. 1d Let i be the steady-state value of the inductor current component on the d-axis on the inverter side. 1q V represents the steady-state value of the inductor current component along the q-axis on the inverter side, s is the state variable, and V Md V is the first modulation signal output by the d-axis current regulator. Mq C is the second modulation signal output by the q-axis current regulator. dc Δ is the DC-side capacitor of the inverter, and Δ is a small signal quantity, that is, a variable that changes very little.

[0052] Construct the first small-signal model between the voltage outer loop and the current inner loop reference values ​​of the inverter:

[0053]

[0054] Among them, I 2dref For the d-axis reference value component of the grid-connected current reference value, U dc G is the DC-side voltage of the inverter. v (s) represents the control parameters of the current inner loop PI controller, where s is the state variable and Δ is a small signal quantity, i.e., a variable that changes very little.

[0055] Based on the equations and the first small-signal model, the second small-signal model of the current inner loop is obtained:

[0056]

[0057] Among them, I 2dref For the d-axis reference value component of the grid-connected current reference value, U dc I is the DC-side voltage of the inverter. ds U is the current source for the inverter. cm i is the AC side voltage of the inverter. 1d i represents the d-axis current component of the inductor current on the inverter side. 1q Let s be the q-axis current component of the inductor current on the inverter side, and s be the state variable, V Md V is the first modulation signal output by the d-axis current regulator. Mq C is the second modulation signal output by the q-axis current regulator. dc V is the DC-side capacitor of the inverter. Md0 V is the steady-state value of the first signal corresponding to the first modulation signal. Mq0 G represents the steady-state value of the second signal corresponding to the second modulation signal. v (s) represents the control parameters of the current inner loop PI controller, where s is the state variable and Δ is a small signal quantity, i.e., a variable that changes very little.

[0058] i 1d i 1q VMd0 and V Mq0 All computational costs are constants and will not be elaborated upon here. Based on the second small-signal model, the first current reference value component and the second current reference value component are obtained. In this embodiment, the second current reference value component is zero and will not be elaborated upon here.

[0059] In the embodiments of this application, constructing the equation relationship between the DC side and the AC side of the inverter includes:

[0060] Construct the second small-signal model of the DC side of the inverter;

[0061] Construct a third small-signal model of the output power of the switching transistor;

[0062] Based on the second and third small-signal models, an equation relationship between the DC and AC sides of the inverter is constructed.

[0063]

[0064] Wherein, ΔP in ΔP is the output power of the inverter. Cdc I is the output power of the DC-side capacitor. 2dref For the d-axis reference value component of the grid-connected current reference value, U dc C is the DC-side voltage of the inverter. dc Δ is the DC-side capacitor of the inverter, and Δ is a small signal quantity, that is, a variable that changes very little.

[0065] Construct a third small-signal model of the output power of the switching transistor:

[0066]

[0067] Among them, P e For the third small-signal model of the output power of the switching transistor, u invd u represents the d-axis component of the inverter's switching transistor output voltage. invq i represents the q-axis component of the inverter's switching transistor output voltage. 1d i represents the d-axis current component of the inductor current on the inverter side. 1q V represents the q-axis current component of the inductor current on the inverter side. Md V is the first modulation signal output by the d-axis current regulator. Mq U is the second modulation signal output by the q-axis current regulator. dc U is the DC-side voltage of the inverter. cm This is the AC side voltage of the inverter.

[0068] Based on the second and third small-signal models, an equation relationship between the DC and AC sides of the inverter is constructed.

[0069] S130, acquire the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value and the first control parameter, wherein the first control parameter is the control parameter of the d-axis current regulator.

[0070] The first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and the first control parameter is obtained. For ease of understanding, in the embodiments of this application, both the d-axis current regulator and the q-axis current regulator are differential controllers; therefore, the control parameter of the d-axis current regulator is G. id (s)=k pd +k id / s, where G id (s) is the first control parameter, k pd k is the proportional coefficient of the d-axis current regulator. id Let be the integral coefficient of the d-axis current regulator, and s be the state variable. The first projected component and the first current reference value are used as state variables and substituted into the first control parameters of the d-axis current regulator to obtain the first modulation signal output by the d-axis current regulator.

[0071] S140, based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop, obtain the suppression feedback signal.

[0072] In this embodiment, a PLL influence suppression feedback is introduced on the q-axis to counteract the influence of the phase-locked loop (PLL) on the q-axis. Specifically, based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the PLL, i.e., the voltage component is used as the state variable of the disturbance transfer function, the suppression feedback signal is obtained, where the access point is the PCC point in the figure. The q-axis adopts an asymmetric design with the introduction of the suppression feedback signal to counteract the negative impact of the PLL on the inverter's wideband oscillation, further improving the system's oscillation suppression capability.

[0073] In the embodiments of this application, a suppression feedback signal is obtained based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop, including:

[0074] Based on the disturbance transfer function of the phase-locked loop, the steady-state value of the grid current on the d-axis, the preset conversion coefficient, and the feedback gain of the phase-locked loop, the voltage component of the connection point voltage on the q-axis is converted to obtain the suppression feedback signal of the q-axis current regulator. The preset conversion coefficient is the conversion coefficient between the grid voltage and the phase-locked loop voltage.

[0075] Please see Figure 3 , Figure 3 A schematic diagram of the control structure of the phase-locked loop provided in an embodiment of this application is shown.

[0076] In this embodiment, the phase-locked loop uses the control result of a PI (Proportional Integral) controller, ω g Let ω be the angular frequency of the power grid, ω0 be the output angular frequency of the phase-locked loop, and l / s represent the integrator element, i.e., integrating the input quantity l / s. The transfer function of the small-signal disturbance excited by the phase-locked loop is:

[0077]

[0078] Among them, G PLL (s) is the disturbance transfer function of the phase-locked loop, H PI (s) represents the control parameters of the PI controller in the phase-locked loop, where s is the state variable and V is the variable. m0 This represents the steady-state value of the grid voltage.

[0079] Based on the phase-locked loop (PLL) disturbance transfer function, the steady-state value of the grid-connected current on the d-axis, the preset conversion coefficient, and the PLL feedback gain, the voltage component of the connection point voltage on the q-axis is converted. Specifically, the preset conversion coefficient is the conversion coefficient between the grid voltage and the PLL voltage. The voltage component is converted based on the feedback gain and the preset conversion coefficient to obtain the converted voltage component. This converted voltage component is then substituted as a state component and multiplied by the steady-state value of the grid-connected current on the d-axis to obtain the suppression feedback signal of the q-axis current regulator. The q-axis employs an asymmetric design that introduces the suppression feedback signal to offset the negative impact of the PLL on the inverter's wideband oscillation.

[0080] S150, acquire the second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal and the second control parameter, wherein the second control parameter is the control parameter of the q-axis current regulator, and the first control parameter and the second control parameter are asymmetric control parameters.

[0081] The second modulation signal output by the q-axis current regulator is obtained based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameter. In this embodiment, the control parameter of the q-axis current regulator is G. iq (s)=k pq +k iq / s, where G iq (s) is the second control parameter, k pq k is the proportional coefficient of the q-axis current regulator. iq is the integral coefficient of the q-axis current regulator, and s is the state variable.

[0082] The second projection component, the second current reference value component, and the suppression feedback signal are used as state variables. The first projection component and the first current reference value are used as state variables and substituted into the second control parameters of the q-axis current regulator to obtain the second modulation signal output by the q-axis current regulator.

[0083] In this embodiment, the first and second control parameters are asymmetric control parameters, meaning that the proportional and integral coefficients of the q-axis current regulator and the d-axis current regulator are both asymmetric. The use of asymmetric control parameters for the d-axis and q-axis suppresses the negative impact of the phase-locked loop in the control loop, thereby improving the system's oscillation suppression capability.

[0084] S160 controls the switching transistor according to the first modulation signal and the second modulation signal.

[0085] The pulse width modulation (PWM) gain of the switching transistor is obtained based on the first and second modulation signals, and the switching transistor is controlled based on the PWM gain. Without changing the inverter's control loop structure or adding an additional auxiliary control loop, asymmetric control parameters on the d-axis and q-axis improve the system's oscillation suppression capability, avoiding an overly complex inverter control structure. Furthermore, the q-axis employs an asymmetric design that introduces a suppression feedback signal to offset the negative impact of the phase-locked loop on the inverter's wideband oscillations, further enhancing the system's oscillation suppression capability while simplifying the inverter's control structure.

[0086] In the embodiments of this application, the inverter control method further includes:

[0087] Obtain a first steady-state current value and a second steady-state current value, wherein the first steady-state current value is the steady-state current value of the output current of the switching transistor on the q-axis, and the second steady-state current value is the steady-state current value of the output current of the switching transistor on the d-axis;

[0088] Acquiring the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and the first control parameter, including:

[0089] Based on the first steady-state value of the current and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the first feedforward signal;

[0090] The first component difference is added to the first feedforward signal to obtain the first control signal, wherein the first component difference is the difference between the first projection component and the first current reference value.

[0091] Obtain the first modulation signal output by the d-axis current regulator based on the first control signal and the first control parameters;

[0092] Acquiring the second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameters, including:

[0093] Based on the steady-state value of the second current and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the second feedforward signal;

[0094] The second component difference, the second feedforward signal, and the suppression feedback signal are added together to obtain the second control signal, wherein the second component difference is the difference between the second projection component and the second current reference value.

[0095] Obtain the first modulation signal output by the q-axis current regulator based on the second control signal and the second control parameters.

[0096] Please see Figure 4 , Figure 4 A schematic diagram of the d-axis current control inner loop provided in an embodiment of this application is shown.

[0097] Please see Figure 5 , Figure 5 A schematic diagram of the q-axis current control inner loop provided in an embodiment of this application is shown.

[0098] Under steady-state operation of the inverter, the output phase angle of the phase-locked loop (PLL) is synchronized with the grid. When a small disturbance occurs in the grid voltage, due to the dynamic adjustment characteristics of the PLL, the output angular frequency of the PLL is no longer equal to the grid angular frequency. This results in a phase angle deviation between the inverter's dq coordinate system and the grid's dq coordinate system, allowing us to obtain the equivalent control structures of the d-axis current control inner loop and the q-axis current control inner loop. We obtain the first and second steady-state current values, where the first steady-state current value is the q-axis steady-state value of the switch's output current, and the second steady-state current value is the d-axis steady-state value of the switch's output current.

[0099] In the picture, This represents the d-axis component of the grid-connected current reference value in the dq coordinate system of the inverter. I represents the d-axis current projection component in the dq coordinate system of the power grid. q0 This is the first steady-state value of the current. The voltage component of the connection point voltage on the q-axis in the dq coordinate system of the power grid is transformed according to the first steady-state current value and the disturbance transfer function of the phase-locked loop (PLL). Specifically, the voltage component is substituted as a state component into the PLL's disturbance transfer function and multiplied by the first steady-state current value to obtain the first feedforward signal. The first projected component is subtracted from the first current reference value to obtain the first component difference. The first component difference is added to the first feedforward signal to obtain the first control signal. The first control signal is substituted as a state component into the first control parameters to obtain the first modulation signal output by the d-axis current regulator based on the first control signal and the first control parameters.

[0100] In the picture, This represents the q-axis component of the grid-connected current reference value in the dq coordinate system of the inverter. The voltage component is transformed based on the second steady-state current value and the phase-locked loop's (PLL) disturbance transfer function, representing the q-axis current projection component in the grid's dq coordinate system. This transformation involves substituting the voltage component as a state component into the PLL's disturbance transfer function and multiplying it by the second steady-state current value to obtain the second feedforward signal. The second projection component is subtracted from the second current reference value to obtain the second component difference. This difference, the second feedforward signal, and the suppression feedback signal are added together to obtain the second control signal. The second control signal is then substituted as a state component into the second control parameters to obtain the first modulation signal output by the q-axis current regulator based on the second control signal and the second control parameters. By introducing the first and second feedforward signals, the phase angle deviation between the inverter's dq coordinate system and the grid's dq coordinate system is eliminated, further offsetting the negative impact of the PLL on the inverter's wideband oscillation.

[0101] In embodiments of this application, controlling the switching transistor according to the first modulation signal and the second modulation signal includes:

[0102] Obtain the steady-state value of the first signal corresponding to the first modulation signal, and the steady-state value of the second signal corresponding to the second modulation signal;

[0103] Based on the stable value of the first signal and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the third feedforward signal;

[0104] The third feedforward signal is added to the first modulation signal to obtain the updated first modulation signal;

[0105] Based on the stable value of the second signal and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the fourth feedforward signal;

[0106] The fourth feedforward signal is added to the second modulation signal to obtain the updated second modulation signal;

[0107] Based on the updated first modulation signal and the updated second modulation signal, the pulse width modulation gain of the switching transistor is obtained, and the switching transistor is controlled based on the pulse width modulation gain.

[0108] Obtain the steady-state value of the first signal corresponding to the first modulation signal, and the steady-state value of the second signal corresponding to the second modulation signal. Based on the steady-state value of the first signal and the perturbation transfer function of the phase-locked loop, convert the voltage component, that is, substitute the voltage component as a state component into the perturbation transfer function of the phase-locked loop, and multiply it with the steady-state value of the first signal to obtain the third feedforward signal. Add the third feedforward signal to the first modulation signal to obtain the updated first modulation signal;

[0109] Based on the stable value of the second signal and the perturbation transfer function of the phase-locked loop (PLL), the voltage component is transformed by substituting it as a state component into the PLL's perturbation transfer function and multiplying it with the steady-state value of the second signal to obtain the fourth feedforward signal. The fourth feedforward signal is then added to the second modulation signal to update the second modulation signal. Based on the updated first and second modulation signals, the pulse width modulation (PWM) gain of the switching transistor is obtained, and the switching transistor is controlled based on this PWM gain. By introducing the third and fourth feedforward signals, the phase angle deviation between the inverter's dq coordinate system and the grid's dq coordinate system is eliminated, further offsetting the negative impact of the PLL on the inverter's wideband oscillation.

[0110] In the embodiments of this application, the inverter control method further includes:

[0111] Construct the impedance matrix model of the inverter;

[0112] Construct the hysteresis matrix of the inverter based on the impedance matrix model;

[0113] The oscillation characteristics of the inverter are determined based on the eigenvalue curves corresponding to the hysteresis matrix.

[0114] Please see Figure 6 , Figure 6 The transfer function model of the inverter provided in the embodiment of this application is shown.

[0115] The inverter's transfer function model includes multiple sub-transfer function models, which are shown in the figure as follows:

[0116]

[0117]

[0118] Where, k pd k is the proportional coefficient of the d-axis current regulator. id k is the integral coefficient of the d-axis current regulator. pq k is the proportional coefficient of the q-axis current regulator.iq G is the integral coefficient of the q-axis current regulator. PLL (s) is the disturbance transfer function of the phase-locked loop, H PI (s) represents the control parameters of the PI controller in the phase-locked loop, where s is the state variable and V is the variable. m0 Let i be the steady-state value of the grid voltage. 2q0 Let i be the steady-state value of the grid-connected current component on the q-axis. 2d0 G represents the steady-state value of the grid-connected current component on the d-axis, where K is the feedback gain; g,c T is the preset conversion factor. s V is the sampling period. Md0 V is the steady-state value of the first signal corresponding to the first modulation signal. Mq0 L1 is the steady-state value of the second signal corresponding to the second modulation signal, L2 is the first filter inductor, and C is the second filter inductor. f For the filter capacitor, ω1 is the rated angular frequency of the power grid, and R... d It is a passive damping resistor.

[0119] Based on the sub-transfer function models in the diagram, the impedance matrix model of the inverter can be constructed as follows:

[0120]

[0121] Among them, Y invdq For the impedance matrix model, I m G is a 2x2 current matrix, where G is the pulse width modulation gain of the switching transistor. v (s) represents the control parameters of the current inner loop PI controller.

[0122] Please see Figure 7 , Figure 7 An example diagram of the characteristic value curve of the grid impedance of 32mH provided in the embodiment of this application is shown.

[0123] The photovoltaic system is connected to the grid via an inverter. Based on the eigenvalue curves corresponding to the hysteresis matrix, the oscillation characteristics of the inverter are determined. In this embodiment, oscillation analysis results are obtained when the grid impedance is 32mH and 35mH. When the grid impedance is 32mH, the eigenvalue curves corresponding to the hysteresis matrix do not encircle the point (1, j0), indicating that the photovoltaic system can operate stably.

[0124] Please see Figure 8 , Figure 8 An example diagram of the characteristic value curve of the grid impedance of 35mH provided in the embodiment of this application is shown.

[0125] When the grid impedance increases to 35mH, the eigenvalue curve corresponding to the hysteresis matrix surrounds the point (1, j0), at which point the photovoltaic system loses stability and oscillates.

[0126] Please see Figure 9 , Figure 9 An example diagram of the grid-connected current waveform with a grid impedance of 32mH, provided in an embodiment of this application, is shown.

[0127] Please see Figure 10 , Figure 10 An example diagram of the grid-connected current waveform with a grid impedance of 35mH, provided in an embodiment of this application, is shown.

[0128] The figure shows the grid-connected current waveforms when the grid impedance is 32mH and 35mH respectively. The inverter control method provided in this embodiment improves the stability of the photovoltaic grid-connected inverter and the correctness and effectiveness of oscillation suppression, significantly improves the adaptability of the photovoltaic grid-connected inverter to the grid impedance, and promotes the local consumption of photovoltaic power.

[0129] This application provides a control method for an inverter, comprising: determining a first projection component of the grid-connected current on the d-axis and a second projection component on the q-axis based on the output phase angle of the phase-locked loop (PLL); obtaining a first current reference value component and a second current reference value component; obtaining a first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and a first control parameter; obtaining a suppression feedback signal based on the voltage component of the connection point voltage on the q-axis and the disturbance transfer function of the PLL; obtaining a second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameter; and controlling a switching transistor based on the first and second modulation signals. Without changing the inverter's control loop structure or adding an additional auxiliary control loop, the asymmetric control parameters for the d-axis and q-axis improve the system's oscillation suppression capability, avoiding an overly complex inverter control structure. Furthermore, the asymmetric design of the q-axis, incorporating a suppression feedback signal, offsets the negative impact of the PLL on the inverter's wideband oscillation, further improving the system's oscillation suppression capability while simplifying the inverter's control structure.

[0130] Example 2

[0131] Please see Figure 11 , Figure 11 A schematic diagram of the control device for an inverter according to an embodiment of this application is shown. The inverter includes a switching transistor, a phase-locked loop (PLL), a d-axis current regulator, and a q-axis current regulator. The switching transistor is connected to the input terminals of the d-axis and q-axis current regulators respectively via the PLL. The output terminals of both the d-axis and q-axis current regulators are connected to the switching transistor. The inverter is connected to the power grid via a connection point. Figure 11 The control device 200 of the inverter includes:

[0132] The projection component determination module 210 is used to determine the first projection component of the grid-connected current on the d-axis and the second projection component on the q-axis based on the output phase angle of the phase-locked loop.

[0133] The reference value component determination module 220 is used to obtain the first current reference value component and the second current reference value component, wherein the first current reference value is the component of the grid-connected current reference value on the d-axis, and the second current reference value is the component of the grid-connected current reference value on the q-axis.

[0134] The first modulation signal acquisition module 230 is used to acquire the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value and the first control parameter, wherein the first control parameter is the control parameter of the d-axis current regulator.

[0135] The suppression feedback signal acquisition module 240 is used to obtain the suppression feedback signal based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop;

[0136] The second modulation signal acquisition module 250 is used to acquire the second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal and the second control parameter, wherein the second control parameter is the control parameter of the q-axis current regulator, and the first control parameter and the second control parameter are asymmetric control parameters;

[0137] The switching transistor control module 260 is used to control the switching transistor according to the first modulation signal and the second modulation signal.

[0138] In the embodiments of this application, the suppression feedback signal obtaining module 240 is further used to convert the voltage component of the access point voltage on the q axis according to the disturbance transfer function of the phase-locked loop, the steady-state value of the grid current on the d axis, the preset conversion coefficient and the feedback gain of the phase-locked loop, to obtain the suppression feedback signal of the q-axis current regulator, wherein the preset conversion coefficient is the conversion coefficient between the grid voltage and the phase-locked loop voltage.

[0139] In embodiments of this application, the inverter control device 200 further includes:

[0140] The current steady-state value acquisition module is used to acquire a first current steady-state value and a second current steady-state value, wherein the first current steady-state value is the current steady-state value of the output current of the switching transistor on the q-axis, and the second current steady-state value is the current steady-state value of the output current of the switching transistor on the d-axis;

[0141] The first modulation signal acquisition module 230 includes:

[0142] The first feedforward signal acquisition submodule is used to convert the voltage component based on the first steady-state current value and the disturbance transfer function of the phase-locked loop to obtain the first feedforward signal.

[0143] The first control signal obtaining submodule is used to add the first component difference to the first feedforward signal to obtain the first control signal, wherein the first component difference is the difference between the first projection component and the first current reference value.

[0144] The first modulation signal output submodule is used to acquire the first modulation signal output by the d-axis current regulator based on the first control signal and the first control parameters;

[0145] The second modulation signal acquisition module 250 includes:

[0146] The second feedforward signal acquisition submodule is used to convert the voltage component based on the second steady-state current value and the disturbance transfer function of the phase-locked loop to obtain the second feedforward signal.

[0147] The second control signal acquisition submodule is used to add the second component difference, the second feedforward signal and the suppression feedback signal to obtain the second control signal, wherein the second component difference is the difference between the second projection component and the second current reference value.

[0148] The second modulation signal output submodule is used to acquire the first modulation signal output by the q-axis current regulator based on the second control signal and the second control parameters.

[0149] In embodiments of this application, the switching transistor control module 260 includes:

[0150] The signal steady-state value acquisition submodule is used to acquire the first signal steady-state value corresponding to the first modulation signal and the second signal steady-state value corresponding to the second modulation signal;

[0151] The third feedforward signal acquisition submodule is used to convert the voltage component based on the first signal stability value and the phase-locked loop disturbance transfer function to obtain the third feedforward signal.

[0152] The first modulation signal update submodule is used to add the third feedforward signal to the first modulation signal to obtain the updated first modulation signal;

[0153] The fourth feedforward signal acquisition submodule is used to convert the voltage component based on the second signal stability value and the phase-locked loop disturbance transfer function to obtain the fourth feedforward signal;

[0154] The second modulation signal update submodule is used to add the fourth feedforward signal to the second modulation signal to obtain the updated second modulation signal;

[0155] The pulse width modulation gain acquisition submodule is used to obtain the pulse width modulation gain of the switching transistor based on the updated first modulation signal and the updated second modulation signal, and to control the switching transistor based on the pulse width modulation gain.

[0156] In embodiments of this application, the reference value component determination module 220 includes:

[0157] The equation construction submodule is used to construct the equation relationship between the DC side and the AC side of the inverter.

[0158] The first small-signal model construction submodule is used to construct the first small-signal model between the voltage outer loop and the current inner loop reference values ​​of the inverter.

[0159] The second small-signal model construction submodule is used to obtain the second small-signal model of the current inner loop based on the equation relationship and the first small-signal model.

[0160] The component determination submodule is used to obtain the first current reference value component and the second current reference value component based on the second small-signal model.

[0161] In the embodiments of this application, the equation construction submodule is also used to construct a second small-signal model of the DC side of the inverter;

[0162] Construct a third small-signal model of the output power of the switching transistor;

[0163] Based on the second and third small-signal models, an equation relationship between the DC and AC sides of the inverter is constructed.

[0164] In embodiments of this application, the inverter control device 200 further includes:

[0165] The matrix model building module is used to build the impedance matrix model of the inverter;

[0166] The hysteresis matrix construction module is used to construct the inverter's hysteresis matrix based on the impedance matrix model.

[0167] The oscillation characteristic determination module is used to generate the oscillation characteristic determination result of the inverter based on the eigenvalue curve corresponding to the hysteresis matrix.

[0168] This application embodiment also provides a computing device, including:

[0169] The memory is configured to store instructions;

[0170] The processor is configured to retrieve instructions from memory and, when executing the instructions, to implement the aforementioned inverter control method.

[0171] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured; adjusting kernel parameters can help address issues that cannot accurately identify different behavioral scenarios.

[0172] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0173] This application also provides a machine-readable storage medium storing instructions that cause a machine to execute the above-described inverter control method.

[0174] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0175] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0176] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0177] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0178] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0179] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0180] Machine-readable storage media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0181] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0182] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A control method for an inverter, characterized in that, The inverter includes a switching transistor, a phase-locked loop (PLL), a d-axis current regulator, and a q-axis current regulator. The switching transistor is connected to the input terminals of the d-axis and q-axis current regulators respectively via the PLL. The output terminals of the d-axis and q-axis current regulators are both connected to the switching transistor. The inverter is connected to the power grid via a connection point. The control method of the inverter includes: Based on the output phase angle of the phase-locked loop, determine the first projection component of the grid-connected current on the d-axis and the second projection component on the q-axis; Obtain the first current reference value component and the second current reference value component, wherein the first current reference value is the component of the grid-connected current reference value on the d-axis, and the second current reference value is the component of the grid-connected current reference value on the q-axis. Obtain the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and the first control parameter, wherein the first control parameter is the control parameter of the d-axis current regulator; Based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop, the suppression feedback signal is obtained; The second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameter is obtained, wherein the second control parameter is the control parameter of the q-axis current regulator, and the first control parameter and the second control parameter are asymmetric control parameters; The switching transistor is controlled according to the first modulation signal and the second modulation signal; The step of obtaining the suppression feedback signal based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop includes: Based on the disturbance transfer function of the phase-locked loop, the steady-state value of the grid current on the d-axis, the preset conversion coefficient, and the feedback gain of the phase-locked loop, the voltage component of the access point voltage on the q-axis is converted to obtain the suppression feedback signal of the q-axis current regulator. The preset conversion coefficient is the conversion coefficient between the grid voltage and the phase-locked loop voltage. The step of controlling the switching transistor according to the first modulation signal and the second modulation signal includes: Obtain the first steady-state value of the first signal corresponding to the first modulation signal, and the second steady-state value of the second signal corresponding to the second modulation signal; Based on the steady-state value of the first signal and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the third feedforward signal; The third feedforward signal is added to the first modulation signal to obtain the updated first modulation signal; Based on the steady-state value of the second signal and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the fourth feedforward signal; The fourth feedforward signal is added to the second modulation signal to obtain the updated second modulation signal; Based on the updated first modulation signal and the updated second modulation signal, the pulse width modulation gain of the switching transistor is obtained, and the switching transistor is controlled based on the pulse width modulation gain.

2. The control method for the inverter according to claim 1, characterized in that, The control method for the inverter also includes: Obtain a first steady-state current value and a second steady-state current value, wherein the first steady-state current value is the steady-state current value of the output current of the switching transistor on the q-axis, and the second steady-state current value is the steady-state current value of the output current of the switching transistor on the d-axis; The step of obtaining the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value, and the first control parameter includes: Based on the first steady-state value of the current and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the first feedforward signal; The first component difference is added to the first feedforward signal to obtain the first control signal, wherein the first component difference is the difference between the first projection component and the first current reference value. Obtain the first modulation signal output by the d-axis current regulator based on the first control signal and the first control parameter; The step of obtaining the second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal, and the second control parameters includes: Based on the second steady-state current value and the disturbance transfer function of the phase-locked loop, the voltage component is converted to obtain the second feedforward signal; The second component difference, the second feedforward signal, and the suppression feedback signal are added together to obtain the second control signal, wherein the second component difference is the difference between the second projection component and the second current reference value; Obtain the first modulation signal output by the q-axis current regulator based on the second control signal and the second control parameter.

3. The control method for the inverter according to claim 1, characterized in that, The acquisition of the first current reference value component and the second current reference value component includes: Construct the equation relationship between the DC side and AC side of the inverter; Construct a first small-signal model between the reference values ​​of the voltage outer loop and the current inner loop of the inverter; Based on the aforementioned equation and the first small-signal model, the second small-signal model of the current inner loop is obtained; Based on the second small-signal model, the first current reference value component and the second current reference value component are obtained.

4. The control method for the inverter according to claim 3, characterized in that, The equation relating the DC and AC sides of the inverter is constructed as follows: Construct a second small-signal model of the DC side of the inverter; Construct a third small-signal model of the output power of the switching transistor; Based on the second small-signal model and the third small-signal model, an equation relationship is constructed between the DC side and the AC side of the inverter.

5. The control method for the inverter according to claim 1, characterized in that, The control method for the inverter also includes: Construct the impedance matrix model of the inverter; Based on the impedance matrix model, the hysteresis matrix of the inverter is constructed; Based on the eigenvalue curves corresponding to the hysteresis matrix, the oscillation characteristics determination result of the inverter is generated.

6. A control device for an inverter, characterized in that, The inverter includes a switching transistor, a phase-locked loop (PLL), a d-axis current regulator, and a q-axis current regulator. The switching transistor is connected to the input terminals of the d-axis current regulator and the q-axis current regulator respectively through the PLL. The output terminals of the d-axis current regulator and the q-axis current regulator are both connected to the switching transistor. The inverter is connected to the power grid through a connection point. The control device for the inverter includes: The projection component determination module is used to determine the first projection component of the grid-connected current on the d-axis and the second projection component on the q-axis based on the output phase angle of the phase-locked loop. The reference value component determination module is used to obtain a first current reference value component and a second current reference value component, wherein the first current reference value is the component of the grid-connected current reference value on the d-axis, and the second current reference value is the component of the grid-connected current reference value on the q-axis. The first modulation signal acquisition module is used to acquire the first modulation signal output by the d-axis current regulator based on the first projection component, the first current reference value and the first control parameter, wherein the first control parameter is the control parameter of the d-axis current regulator; The suppression feedback signal acquisition module is used to obtain the suppression feedback signal based on the voltage component of the access point voltage on the q-axis and the disturbance transfer function of the phase-locked loop; The second modulation signal acquisition module is used to acquire the second modulation signal output by the q-axis current regulator based on the second projection component, the second current reference value component, the suppression feedback signal and the second control parameter, wherein the second control parameter is the control parameter of the q-axis current regulator, and the first control parameter and the second control parameter are asymmetric control parameters; A switching transistor control module is used to control the switching transistor according to the first modulation signal and the second modulation signal; The suppression feedback signal acquisition module is also used to convert the voltage component of the access point voltage on the q axis according to the disturbance transfer function of the phase-locked loop, the steady-state value of the grid current on the d axis, the preset conversion coefficient and the feedback gain of the phase-locked loop, to obtain the suppression feedback signal of the q-axis current regulator, wherein the preset conversion coefficient is the conversion coefficient between the grid voltage and the phase-locked loop voltage; The switching transistor control module includes: The signal steady-state value acquisition submodule is used to acquire the first signal steady-state value corresponding to the first modulation signal and the second signal steady-state value corresponding to the second modulation signal; The third feedforward signal acquisition submodule is used to convert the voltage component based on the steady-state value of the first signal and the disturbance transfer function of the phase-locked loop to obtain the third feedforward signal. The first modulation signal update submodule is used to add the third feedforward signal to the first modulation signal to obtain the updated first modulation signal; The fourth feedforward signal acquisition submodule is used to convert the voltage component based on the steady-state value of the second signal and the disturbance transfer function of the phase-locked loop to obtain the fourth feedforward signal; The second modulation signal update submodule is used to add the fourth feedforward signal to the second modulation signal to obtain the updated second modulation signal; The pulse width modulation gain acquisition submodule is used to obtain the pulse width modulation gain of the switching transistor based on the updated first modulation signal and the updated second modulation signal, and to control the switching transistor based on the pulse width modulation gain.

7. A computing device, characterized in that, include: The memory is configured to store instructions; The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the control method of the inverter according to any one of claims 1 to 5.

8. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to perform the control method of the inverter according to any one of claims 1 to 5.

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