An inverter current control method and system based on complex phase angle dq transformation

Abstract

The application discloses an inverter current control method and system based on complex phase angle dq transformation, which comprises the following steps: collecting three-phase voltage and current components of an inverter, transforming the three-phase voltage and current components to a two-phase stationary coordinate system, and obtaining a power grid voltage complex vector; performing generalized dq transformation on the power grid voltage complex vector, estimating a complex phase angle and a complex frequency which simultaneously reflect the dynamic of the amplitude and phase of the power grid voltage through a complex variable phase-locked loop; establishing an inverter dynamic model based on the obtained complex phase angle and complex frequency; taking the complex frequency as a feedforward decoupling compensation item of a current controller; the current controller comprises feedforward decoupling compensation and PI feedback regulation, and a modulation voltage instruction signal is calculated by using the current controller; a pulse width modulation signal is generated according to the obtained modulation voltage instruction signal, and power semiconductor switching devices in the inverter are driven. The application improves the dynamic response speed and control precision of the inverter under the disturbance of power grid voltage mutation, frequency fluctuation and the like.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to an inverter current control method based on complex phase angle dq transformation. Background Technology

[0002] With the rapid development of renewable energy, the performance of grid-connected inverters, which are the core interface connecting renewable energy and the power grid, directly affects the stability of the power grid and the power quality. The control strategy of the inverter is the key to determining the performance of the grid-connected inverter.

[0003] Currently, voltage-oriented control methods based on synchronous reference coordinate systems are widely used in industry. These methods use Park transformation to convert three-phase voltage and current into a dq coordinate system that rotates synchronously with the grid voltage, transforming them into DC quantities. Mature PI controllers can then be used to achieve zero steady-state error tracking of the current. However, traditional dq transformation introduces dynamic coupling terms between the d and q axes. Since these coupling terms are unobservable, accurate compensation for the d- and q-axis coupling components in the inverter's output voltage command is impossible. When disturbances such as frequency shifts or voltage dips occur in the grid, control systems using traditional phase-locked loops struggle to detect them, ultimately leading to instability.

[0004] To address this issue, existing technologies have proposed various control strategies. However, most strategies rely on precise differentiation of the grid voltage or complex filter designs, making it difficult to simultaneously achieve dynamic response speed, steady-state tracking accuracy, and disturbance rejection performance in practical applications. Furthermore, they lack robustness to changes in system parameters. Therefore, a novel inverter control method is needed that can achieve complete decoupling and is highly adaptable to grid dynamics. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to enhance the robustness of the grid-connected inverter current control system to grid disturbances without sacrificing control performance during the grid-connected inverter control process.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An inverter current control method based on complex phase angle dq transformation includes:

[0008] Step S1: Real-time acquisition of the three-phase voltage and current components of the inverter, and transformation of the three-phase voltage and current components of the inverter to two-phase stationary states. In the coordinate system, the complex vector of the grid voltage is obtained;

[0009] Step S2: Use the estimated complex phase angle Construct a generalized dq transformation matrix to transform the complex vector of grid voltage. Transform to the generalized dq coordinate system to obtain the voltage quantity. Based on the voltage error between the voltage value and the reference value, the estimated complex phase angle is updated through a closed-loop complex variable phase-locked loop. Sum of complex frequencies Thus, the complex phase angle and complex frequency, which can simultaneously reflect the dynamics of the grid voltage amplitude and phase, can be obtained in real time.

[0010] Step S3: Based on the complex phase angle and complex frequency estimated in Step S2, the inverter current and voltage signals are transformed to the generalized dq coordinate system, and an inverter dynamic model is established. In the inverter dynamic model, the complex phase angle is used to construct the generalized dq transformation matrix to realize coordinate transformation; the complex frequency is used to characterize the grid frequency dynamics and voltage amplitude dynamics, and serves as the feedforward decoupling compensation term of the current controller; the current controller includes feedforward decoupling compensation and PI feedback regulation, and the modulation voltage command signal is calculated using the current controller.

[0011] Step S4: Based on the modulation voltage command signal obtained in step S3, generate a pulse width modulation signal to drive the power semiconductor switching devices in the inverter, thereby achieving final control of the output current.

[0012] The aforementioned inverter current control method based on complex phase angle dq transformation includes, in step S1:

[0013] Define complex phase angle The expression is:

[0014] (1)

[0015] in, The voltage magnitude is a complex vector. The phase angle of a complex vector;

[0016] Complex frequency The definition of is:

[0017] (2)

[0018] in, The normalized rate of change of amplitude. The angular frequency of the power grid, indicated by the superscript. Represents the derivative with respect to time;

[0019] A three-phase stationary coordinate system can be obtained through Clark transformation. The complex vector of grid voltage in the coordinate system is expressed as equation (3):

[0020] (3)

[0021] for Power grid voltage vector in coordinate system , The grid voltage vector is respectively in shaft and Axial components, The imaginary unit, is the base of the natural logarithm.

[0022] In the aforementioned inverter current control method based on complex phase angle dq transformation, in step S2, the generalized dq transformation based on complex phase angle is defined as:

[0023] (4)

[0024] in, A complex vector in the generalized dq coordinate system. This is a real-time estimate of the complex phase angle. This is an estimate of the fundamental positive-sequence voltage amplitude of the power grid. This is an estimated value for the phase of the fundamental positive sequence voltage of the power grid.

[0025] In the aforementioned inverter current control method based on complex phase angle dq transformation, in step S2, the matrix expression of the generalized dq transformation is:

[0026] (5)

[0027] in, The real-time estimate of the complex frequency is obtained by a complex variable phase-locked loop through closed-loop estimation based on the relationship between the complex phase angle and the complex frequency as shown in equation (2), including the observed value of the normalized rate of change of amplitude and the observed value of the angular frequency.

[0028] In the aforementioned inverter current control method based on complex phase angle dq transformation, in step S3, the estimated complex phase angle obtained in real-time estimation by the complex variable phase-locked loop in step S2 is used. Sum of complex frequencies Establish a dynamic model of the inverter in the generalized dq coordinate system, including:

[0029] Based on the circuit topology of the three-phase L-type inverter, the grid-side current is selected as the state variable. Assuming that the voltages and currents of phases A, B, and C are symmetrically balanced, the state equations in the three-phase stationary coordinate system are listed according to Kirchhoff's voltage and current laws as follows:

[0030] (6)

[0031] in, For filtering inductors, For line resistance, The inverter output current is shown in a three-phase stationary coordinate system. This is the inverter output voltage. This refers to the grid voltage.

[0032] Transform the state equations in the three-phase stationary coordinate system into the state equations in the generalized dq coordinate system:

[0033] (7)

[0034] in, The inverter output current is defined in the generalized dq coordinate system. This is a real-time estimate of the complex frequency. The inverter output voltage is defined in the generalized dq coordinate system. The grid voltage in the generalized dq coordinate system;

[0035] In the state equation form of the generalized dq coordinate system, the current is decomposed into two components: the d-axis and the q-axis. Substituting the dq-axis components of each variable into the state equation, we get:

[0036] (8)

[0038] in This represents the d-axis component of the inverter output current. This represents the q-axis component of the inverter output current. The d-axis component of the inverter output voltage. This represents the q-axis component of the inverter output voltage. The d-axis component of the grid voltage. The grid voltage q-axis component, These are the observed angular frequencies. This represents the observed rate of voltage change.

[0039] Based on the principle that the real and imaginary parts are equal, the real state equations for the d and q axes are obtained respectively:

[0040] (9)

[0041] AC current control is achieved using a PI controller, which is represented as follows:

[0042] (10)

[0043] in and The current control represents the proportional and integral gain, respectively. This indicates the inverter output command voltage reference value. Represents the current loop transfer function. = - It is a current control error. The complex change in the current reference command in the generalized dq coordinate system. This represents the complex change in actual current in the generalized dq coordinate system.

[0044] In the aforementioned inverter current control method based on complex phase angle dq transformation, in step S3, the current controller is represented as follows:

[0045] (11)

[0046] in, This is the reference value for the dq axis current.

[0047] In the aforementioned inverter current control method based on complex phase angle dq transformation, in step S3, the current error, after passing through the current controller, undergoes grid voltage feedforward and coupling component compensation to finally obtain the output voltage command, including the d-axis reference component of the inverter output voltage. and the q-axis reference component of the inverter output voltage :

[0048] (12)

[0049] in, This is the reference value for the d-axis current component. This is the reference value for the q-axis current component. This is the d-axis reference value for the inverter output voltage. This is the q-axis reference value for the inverter output voltage.

[0050] A computer system includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described above.

[0051] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0052] A computer program product includes a computer program that, when executed by a processor, implements the steps of the above-described method.

[0053] The beneficial effects achieved by this invention are as follows: This invention provides an inverter current control method based on complex phase angle dq transformation. By introducing complex phase angle and complex frequency, a generalized inverter dynamic behavior model describing the dual dynamics of grid amplitude and phase is constructed. The feedforward decoupling controller designed based on the model can theoretically eliminate the rotational coupling term caused by angular frequency dynamics and the amplitude dynamic coupling term caused by amplitude normalization change dynamics within the system, thereby improving the dynamic response speed and steady-state tracking accuracy of the current loop.

[0054] The grid-connected inverter control method of this invention does not rely on the dynamic performance of traditional phase-locked loops. When large disturbances occur in the grid voltage, such as frequency changes, phase jumps, or voltage dips, it can instantly capture the real dynamics of the grid and perform precise compensation, effectively suppressing current oscillations and overshoot, and enhancing the operating stability and robustness of the inverter under weak grid or fault conditions.

[0055] Meanwhile, by feeding forward compensation to the amplitude coupling term caused by voltage amplitude dynamics, the defect of current runaway in the traditional dq control model during severe voltage sag is solved, enabling the inverter to maintain stable and accurate current control and strong low voltage ride-through capability.

[0056] Furthermore, this invention precisely linearizes and decouples complex nonlinear and time-varying controlled objects, simplifies the parameter design and tuning process of the controller, reduces dependence on complex parameter tuning, and enhances the applicability and portability of the control algorithm. Attached Figure Description

[0057] Figure 1 This is a flowchart of an inverter current control method based on complex phase angle dq transformation in Embodiment 1 of the present invention;

[0058] Figure 2 This is a topology diagram of the three-phase L-type grid-connected inverter in Embodiment 1 of the present invention;

[0059] Figure 3 This is a control structure diagram of the three-phase L-type grid-connected inverter in Embodiment 1 of the present invention;

[0060] Figure 4 This is a schematic diagram of the control principle of the grid-connected inverter system in Embodiment 1 of the present invention. Detailed Implementation

[0061] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0062] Example 1

[0063] Please see Figures 1-4 This embodiment provides an inverter current control method based on complex phase angle dq transformation, including the following steps:

[0064] Step S1: The signal acquisition and preprocessing module is used to collect the three-phase voltage and current components of the inverter in real time, and the three-phase voltage and current components of the inverter are transformed into two-phase stationary states. In a coordinate system, including:

[0065] Define complex phase angle The expression is:

[0066] (1)

[0067] in, The voltage magnitude is a complex vector. The phase angle of a complex vector;

[0068] Complex frequency The definition of is:

[0069] (2)

[0070] in, The normalized rate of change of amplitude. The angular frequency of the power grid, indicated by the superscript. It represents the derivative with respect to time.

[0071] The complex phase angle and complex frequency Real-time estimation is achieved through a complex variable phase-locked loop based on complex phase angle and complex frequency, enabling symmetrical and unified closed-loop observation and accurate estimation of voltage rate of change (RoCoV) and frequency change. The three-phase stationary coordinate system can be obtained through Clark transformation. The complex vector of grid voltage in the coordinate system is expressed as equation (3):

[0072] (3)

[0073] for Power grid voltage vector in coordinate system , The grid voltage vector is respectively in shaft and Axial components, The imaginary unit, is the base of the natural logarithm.

[0074] Step S2: For The complex vector of grid voltage in the coordinate system is subjected to generalized dq transformation. Through a complex variable phase-locked loop, the complex phase angle and complex frequency, which can simultaneously reflect the dynamics of grid voltage amplitude and phase, are estimated in real time.

[0075] Define the generalized dq transform based on the complex phase angle as follows:

[0076] (4)

[0077] in, A complex vector in the generalized dq coordinate system. This is a real-time estimate of the complex phase angle. This is an estimate of the fundamental positive-sequence voltage amplitude of the power grid. This is an estimated value for the phase of the fundamental positive sequence voltage of the power grid.

[0078] The matrix expression for the generalized dq transform is:

[0079] (5)

[0080] in, The real-time estimate of the complex frequency is obtained by a complex variable phase-locked loop through closed-loop estimation based on the relationship between the complex phase angle and the complex frequency as shown in equation (2), including the observed value of the normalized rate of change of amplitude and the observed value of the angular frequency.

[0081] Step S3: Based on the complex phase angle and complex frequency estimated in Step S2, transform the inverter current and voltage signals to the generalized dq coordinate system and establish an inverter dynamic model. In the inverter dynamic model, the complex phase angle is used to construct the generalized dq transformation matrix to achieve coordinate transformation; the complex frequency is used to characterize the grid frequency dynamics and voltage amplitude dynamics, and serves as the feedforward decoupling compensation term for the current controller. A current controller is constructed based on the inverter dynamic model. The current controller includes feedforward decoupling compensation and PI feedback regulation. The modulated voltage command signal is calculated using the current controller. This includes:

[0082] Based on the circuit topology of the three-phase L-type inverter, the grid-side current is selected as the state variable. Assuming that the voltages and currents of phases A, B, and C are symmetrically balanced, the state equations in the three-phase stationary coordinate system are listed according to Kirchhoff's voltage and current laws as follows:

[0083] (6)

[0084] in, For filtering inductors, For line resistance, The inverter output current is shown in a three-phase stationary coordinate system. This is the inverter output voltage. This is the grid voltage.

[0085] Transform the state equations in the three-phase stationary coordinate system into the state equations in the generalized dq coordinate system:

[0086] (7)

[0087] in, The inverter output current is defined in the generalized dq coordinate system. This is a real-time estimate of the complex frequency. The inverter output voltage is defined in the generalized dq coordinate system. The voltage is the grid voltage in the generalized dq coordinate system.

[0088] The grid-connected inverter current control system adopts current closed-loop control, which is the current controller shown in equation (11). The current in the state equation form under the generalized dq coordinate system is decomposed into two components, the d-axis and the q-axis. At the same time, the current is decomposed into two components, the d-axis and the q-axis, in the state equation form under the generalized dq coordinate system. Substituting the dq-axis components of each variable into the state equation, we get:

[0089] (8)

[0091] in This represents the d-axis component of the inverter output current. This represents the q-axis component of the inverter output current. The d-axis component of the inverter output voltage. This represents the q-axis component of the inverter output voltage. The d-axis component of the grid voltage. The grid voltage q-axis component, These are the observed angular frequencies. This represents the observed rate of voltage change.

[0092] Based on the principle that the real and imaginary parts are equal, the real state equations for the d and q axes are obtained respectively:

[0093] (9)

[0094] AC current control is achieved using a PI controller, which is represented as follows:

[0095] (10)

[0096] in and The current control represents the proportional and integral gain, respectively. This indicates the inverter output command voltage reference value. Represents the current loop transfer function. = - It is a current control error. The complex change in the current reference command in the generalized dq coordinate system. This represents the complex change in actual current in the generalized dq coordinate system.

[0097] The current controller is then represented as:

[0098] (11)

[0099] in, The reference value for the dq axis current is given. Equation (11) is the current closed-loop control expression obtained by combining the current state equation of equation (9) with the PI control law shown in equation (10).

[0100] The PI feedback control section eliminates current tracking errors, while the feedforward decoupling compensation section actively counteracts grid voltage disturbances and internal dynamic coupling. After the current error passes through the current controller, it undergoes grid voltage feedforward and coupling component compensation to ultimately obtain the output voltage command, including the d-axis reference component of the inverter output voltage. and the q-axis reference component of the inverter output voltage :

[0101] (12)

[0102] in, This is the reference value for the d-axis current component. This is the reference value for the q-axis current component. This is the d-axis reference value for the inverter output voltage. This is the q-axis reference value for the inverter output voltage.

[0103] Step S4: Based on the final voltage modulation reference signal in step S3, generate a pulse width modulation (PWM) signal to drive the power semiconductor switching devices in the inverter, thereby achieving final control of the output current.

[0104] In summary, this embodiment addresses the performance limitations of traditional phase-locked loop (PLL) based dq-transformer control methods in the face of dynamic power grids by introducing a complex variable-based grid-connected inverter current control system. By introducing a complex phase angle frequency that can uniformly describe the dual dynamics of system amplitude and phase, an accurate system description framework is constructed, providing rotational coupling terms caused by angular frequency dynamics and amplitude dynamic coupling terms caused by amplitude normalization changes.

[0105] The current controller in this embodiment, through a feedforward compensation unit, can actively, in real-time, and accurately cancel all the aforementioned internal coupling terms and external grid voltage disturbances. For a PI feedback regulator, this simplifies the originally complex, nonlinear, and time-varying controlled object into two independent, linear first-order inertial systems. This not only simplifies the design and tuning of controller parameters but also ensures the speed and stability of the control loop. Therefore, the method adopted in this embodiment has significant advantages over traditional control methods in terms of dynamic response speed, steady-state tracking accuracy, and robustness to grid disturbances. By compensating for the amplitude dynamic coupling terms, current oscillations during grid voltage dips or rises can be effectively suppressed, improving low-voltage ride-through capability.

[0106] Example 2

[0107] A computer system includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described above.

[0108] Example 3

[0109] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0110] Example 4

[0111] A computer program product includes a computer program that, when executed by a processor, implements the steps of the above-described method.

[0112] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0113] 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 1The function specified in one or more boxes.

[0114] 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.

[0115] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An inverter current control method based on complex phase angle dq transformation, characterized in that, include: Step S1: Real-time acquisition of the three-phase voltage and current components of the inverter, and transformation of the three-phase voltage and current components of the inverter to two-phase stationary states. In the coordinate system, the complex vector of the grid voltage is obtained; Step S2: Use the estimated complex phase angle Construct a generalized dq transformation matrix to transform the complex vector of grid voltage. Transform to the generalized dq coordinate system to obtain the voltage quantity. Based on the voltage error between the voltage value and the reference value, the estimated complex phase angle is updated through a closed-loop complex variable phase-locked loop. Sum of complex frequencies This allows for the real-time acquisition of complex phase angles and complex frequencies that simultaneously reflect the dynamics of the grid voltage amplitude and phase. Step S3: Based on the complex phase angle and complex frequency estimated in Step S2, the inverter current and voltage signals are transformed to the generalized dq coordinate system, and an inverter dynamic model is established. In the inverter dynamic model, the complex phase angle is used to construct the generalized dq transformation matrix to realize coordinate transformation; the complex frequency is used to characterize the grid frequency dynamics and voltage amplitude dynamics, and serves as the feedforward decoupling compensation term of the current controller; the current controller includes feedforward decoupling compensation and PI feedback regulation, and the modulation voltage command signal is calculated using the current controller. Step S4: Based on the modulation voltage command signal obtained in step S3, generate a pulse width modulation signal to drive the power semiconductor switching devices in the inverter, thereby achieving final control of the output current.

2. The inverter current control method based on complex phase angle dq transformation according to claim 1, characterized in that, Step S1 includes: Define complex phase angle The expression is: （1） in, The voltage magnitude is a complex vector. The phase angle of a complex vector; Complex frequency The definition of is: （2） in, The normalized rate of change of amplitude. The angular frequency of the power grid is indicated by the superscript. Represents the derivative with respect to time; A three-phase stationary coordinate system can be obtained through Clark transformation. The complex vector of grid voltage in the coordinate system is expressed as equation (3): （3） for Power grid voltage vector in coordinate system , The grid voltage vector is respectively in shaft and Axial components, The imaginary unit, It is the base of the natural logarithm.

3. The inverter current control method based on complex phase angle dq transformation according to claim 2, characterized in that, In step S2, the generalized dq transform based on the complex phase angle is defined as: （4） in, A complex vector in the generalized dq coordinate system. This is a real-time estimate of the complex phase angle. This is an estimate of the fundamental positive-sequence voltage amplitude of the power grid. This is an estimated value for the phase of the fundamental positive sequence voltage of the power grid.

4. The inverter current control method based on complex phase angle dq transformation according to claim 3, characterized in that, In step S2, the matrix expression for the generalized dq transform is: （5） in, The real-time estimate of the complex frequency is obtained by a complex variable phase-locked loop through closed-loop estimation based on the relationship between the complex phase angle and the complex frequency as shown in equation (2), including the observed value of the normalized rate of change of amplitude and the observed value of the angular frequency.

5. The inverter current control method based on complex phase angle dq transformation according to claim 4, characterized in that, In step S3, the estimated complex phase angle is obtained based on the real-time estimation of the complex variable phase-locked loop in step S2. Sum of complex frequencies Establish a dynamic model of the inverter in the generalized dq coordinate system, including: Based on the circuit topology of the three-phase L-type inverter, the grid-side current is selected as the state variable. Assuming that the voltages and currents of phases A, B, and C are symmetrically balanced, the state equations in the three-phase stationary coordinate system are listed according to Kirchhoff's voltage and current laws as follows: （6） in, For filtering inductors, For line resistance, The inverter output current is shown in a three-phase stationary coordinate system. This is the inverter output voltage. This refers to the grid voltage. Transform the state equations in the three-phase stationary coordinate system into the state equations in the generalized dq coordinate system: （7） in, The inverter output current is defined in the generalized dq coordinate system. This is a real-time estimate of the complex frequency. The inverter output voltage is defined in the generalized dq coordinate system. The grid voltage in the generalized dq coordinate system; In the state equation form of the generalized dq coordinate system, the current is decomposed into two components: the d-axis and the q-axis. Substituting the dq-axis components of each variable into the state equation, we get: （8） in This represents the d-axis component of the inverter output current. This represents the q-axis component of the inverter output current. The d-axis component of the inverter output voltage. This represents the q-axis component of the inverter output voltage. The d-axis component of the grid voltage. The grid voltage q-axis component, These are the observed angular frequencies. The observed value is the rate of change of voltage. Based on the principle that the real and imaginary parts are equal, the real state equations for the d and q axes are obtained respectively: （9） AC current control is achieved using a PI controller, which is represented as follows: （10） in and The current control represents the proportional and integral gain, respectively. This indicates the inverter output command voltage reference value. Represents the current loop transfer function. = - It is a current control error. The complex change in the current reference command in the generalized dq coordinate system. This represents the complex change in actual current in the generalized dq coordinate system.

6. The inverter current control method based on complex phase angle dq transformation according to claim 5, characterized in that, In step S3, the current controller is represented as: （11） in, This is the reference value for the dq axis current.

7. The inverter current control method based on complex phase angle dq transformation according to claim 6, characterized in that, In step S3, the current error, after passing through the current controller, undergoes grid voltage feedforward and coupling component compensation to finally obtain the output voltage command, including the d-axis reference component of the inverter output voltage. and the q-axis reference component of the inverter output voltage : （12） in, This is the reference value for the d-axis current component. This is the reference value for the q-axis current component. This is the d-axis reference value for the inverter output voltage. This is the q-axis reference value for the inverter output voltage.

8. A computer system comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the grid-connected inverter control method with applied complex variables as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the grid-connected inverter control method with complex variables as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the grid-connected inverter control method with complex variables as described in any one of claims 1-7.

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