Control method and device for improving broadband oscillation stability of grid-forming converter

Abstract

The invention discloses a control method and device for improving broadband oscillation stability of a grid-forming type converter, solves the problem that the grid-forming type converter generates intermediate frequency oscillation after a virtual inductor is introduced, and belongs to the technical field of power electronic grid-connected equipment control. The method comprises the steps that virtual synchronous control is adopted by a grid-forming converter, a VSG reference voltage amplitude is obtained according to an active and reactive control loop, and a converter output voltage reference value is obtained by combining an alternating current voltage and current double closed loop of a virtual inductor, a current value of a grid-connected line is sampled, and a dq-axis component of grid-connected current under a rotating coordinate system is obtained; a differential item obtained after the dq-axis component of the grid-connected current in the rotating coordinate system is multiplied by the virtual inductance passes through a first-order low-pass filter, a dynamic virtual inductance item of the dq axis in the rotating coordinate system is obtained, the dynamic virtual inductance item is introduced into an alternating-current voltage loop input end in an alternating-current voltage and current double closed loop, and the broadband oscillation stability of the grid-forming type converter is improved.

Description

Technical Field

[0001] The present invention relates to a control method and device for improving the broadband oscillation stability of a grid-connected converter, belonging to the technical field of power electronic grid-connected equipment control. Background Art

[0002] Due to the strong spatial and temporal uncertainties and power electronics characteristics of renewable energy, while improving power generation efficiency and grid connection capabilities, they also significantly impact the stability and dynamic behavior of the power grid. The interaction between the power electronics controller and the transmission network in this dual-high system can cause broadband oscillations. Improving the stability of renewable energy grid-connected converter systems within this broadband has become a key research issue.

[0003] The control methods used by new energy grid-connected units are mainly divided into two types: grid-following and grid-forming. The former uses a phase-locked loop to achieve synchronization with the grid, but it suffers from instability problems in weak grids and is unable to build voltage on its own. It cannot operate normally in high-penetration new energy systems. To solve these problems, grid-forming control has emerged. By drawing on the operating principles of synchronous generators, grid-forming control can build AC voltage on its own. Through typical topologies such as virtual synchronous control, it can support the grid voltage and frequency, and demonstrates good adaptability to weak grid operating conditions. However, grid-forming control still has the problem of unstable broadband oscillation under other operating conditions such as strong grids. It is necessary to analyze the stability of grid-forming control under different grid strengths and different frequency bands and propose oscillation suppression methods.

[0004] Grid-connected converters under grid-type control face the risk of low-frequency oscillations in strong power grids. To suppress these oscillations, virtual inductance control is often introduced to effectively increase line impedance, thereby improving system stability. However, as control system parameters, external line parameters, and virtual inductance parameters change, not only low-frequency oscillations can occur, but also the risk of oscillations in the mid-frequency band. The impact of virtual inductance on system stability is not a permanent fix; the factors influencing the decrease in mid-frequency stability after the introduction of virtual inductance require further investigation. Proposing methods to improve the mid-frequency stability of grid-type converters will be a key research focus. Summary of the Invention

[0005] In order to solve the problem of medium frequency oscillation in a grid-type converter after introducing virtual inductance, the present invention provides a control method for improving the broadband oscillation stability of the grid-type converter.

[0006] A control method for improving the broadband oscillation stability of a grid-type converter according to the present invention comprises:

[0007] The grid-type converter adopts virtual synchronous control, including active and reactive power control loops and AC voltage and current double closed loops;

[0008] The VSG reference voltage amplitude is obtained according to the active and reactive power control loop, and then the converter output voltage reference value is obtained by combining the AC voltage and current double closed loop with the introduction of virtual inductance, and then the PWM modulation wave instruction is obtained. Among them, the virtual inductance L is introduced. v The AC voltage and current double closed loop method is:

[0009] Sampling the current value of the grid-connected line, and obtaining the dq-axis components of the grid-connected current in the rotating coordinate system according to coordinate transformation;

[0010] The dq axis components of the grid current in the rotating coordinate system are multiplied by the virtual inductance L v The differential term after the transformation is passed through a first-order low-pass filter to obtain the dynamic virtual inductance term of the dq axis in the rotating coordinate system, and the dynamic virtual inductance term is introduced into the AC voltage loop input end of the AC voltage and current double closed loop.

[0011] As a preference, the dq axis components of the grid-connected current in the rotating coordinate system are i and d and i q ;

[0012] The dynamic virtual inductance terms of the dq axes in the rotating coordinate system are L1 and L2 respectively;

[0013]

[0014] Where s represents the Laplace operator, ω cc is the cutoff frequency of the low-pass filter.

[0015] Preferably, introducing the dynamic virtual inductance term into the AC voltage loop input terminal of the grid-type converter comprises:

[0016] The dq axis virtual input voltages at the input end of the AC voltage loop of the grid-type converter are E d and E q :

[0017] ΔE d =ΔE-ΔL1-R v Δi d

[0018] ΔE q =-ΔL2-R v Δi q

[0019] Where E is the VSG reference voltage amplitude output by the reactive control loop, △ represents the small disturbance of the corresponding variable, R v Indicates the virtual resistance value.

[0020] As a preferred embodiment, the control equation of the AC voltage and current double closed loop with the introduction of virtual inductance is:

[0021]

[0022] Among them, u d 、u q are the dq axis components of the grid connection point voltage, ω n is the grid frequency rating, i ldref 、i lqref are the given values of the dq axis current of the current loop output by the AC voltage loop; i ld 、i lq are the dq axis components of the filter inductor current respectively; d 、φ q , ψ d , ψ q is the intermediate variable, K pV , K iV is the PI control parameter of the voltage loop, K pi , K ii is the PI control parameter of the current loop, L f 、C f Represents filter inductance and filter capacitance, e d 、e q They represent the dq-axis components of the converter output voltage reference value respectively. The superscript c indicates that the variable is expressed in the control coordinate system corresponding to the output angle of the active control loop.

[0023] The beneficial effects of the present invention are to address the problem of medium-frequency oscillation in grid-type converters after the introduction of virtual inductance. By establishing a state-space model of the grid-type converter, the present invention studies the dominant role of virtual inductance in the stability of medium-frequency oscillation in grid control. Furthermore, by sampling the grid-connected current and converting it to the dq coordinate system, the differential term of the dq-axis component of the grid-connected current multiplied by the virtual inductance is passed through a first-order low-pass filter and introduced into the input of the AC voltage loop of the grid control, thereby improving the broadband oscillation stability of the grid-type converter. This method can adapt to various new energy grid-connected scenarios and help improve the small-disturbance stability of the grid-connected converter system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a control method for improving the broadband oscillation stability of a grid-type converter;

[0025] Figure 2 This is a control block diagram of a grid-connected converter used in an embodiment of the present invention;

[0026] Figure 3 Root loci of the influence of virtual inductance on the low-frequency and medium-frequency characteristic roots of the grid-type converter in this embodiment; (a) is the root loci of the low-frequency characteristic roots, and (b) is the root loci of the medium-frequency characteristic roots;

[0027] Figure 4: is a relationship curve between the short-circuit ratio and the intermediate frequency oscillation modal damping ratio under different virtual inductance parameters in this embodiment;

[0028] Figure 5 : is the relationship curve between the voltage loop proportional coefficient and the intermediate frequency modal damping ratio under different virtual inductance parameters in this embodiment;

[0029] Figure 6 The relationship curve between the current loop control coefficient and the intermediate frequency modal damping ratio under different virtual inductance parameters in this embodiment; (a) current loop proportional coefficient (b) current loop integral coefficient

[0030] Figure 7 This is a topology diagram of the optimization control method that introduces dynamic virtual inductance proposed in this embodiment;

[0031] Figure 8 This is the frequency root locus of the system when the virtual inductance value increases after the dynamic virtual inductance control is introduced in this embodiment;

[0032] Figure 9 Figure 1 shows the system power, voltage, and current waveforms after the dynamic virtual inductance is introduced to improve the control strategy when the current loop proportional coefficient increases in this embodiment; where (a) is the output active power, and (b) is the grid-connected point voltage and grid-connected current; Figure 10 When the virtual inductance value increases in this embodiment, the system power and voltage and current waveforms are shown after the dynamic virtual inductance improved control strategy is introduced, where (a) is the output active power and (b) is the grid-connected point voltage and grid-connected current. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0036] The control method for improving the broadband oscillation stability of a grid-type converter in this embodiment includes:

[0037] The grid-type converter adopts virtual synchronous control, including active and reactive power control loops and AC voltage and current double closed loops;

[0038] The VSG reference voltage amplitude is obtained based on the active and reactive power control loop, and then the converter output voltage reference value is obtained by combining the AC voltage and current double closed loop with the introduction of virtual inductance, and then the PWM modulation wave instruction is obtained;

[0039] To address the problem of medium-frequency oscillation in grid-connected converters under grid-type control, this embodiment derives the dominant effect of virtual inductance on the stability of medium-frequency oscillation in grid-type control:

[0040] S1. Establish a state-space model for the grid-connected converter and grid-connected lines under grid-connected control. First, it should be explained that the grid-connected converter employs a typical grid-connected control structure based on virtual synchronization. Its control system uses a dual AC voltage and current closed-loop structure based on the power loop output voltage reference to derive the converter's PWM modulation wave command value. Since the grid-connected lines are primarily inductive and have relatively small parasitic resistances, the impedance of the grid-connected lines will be modeled using the inductive and resistive properties.

[0041] According to the virtual synchronous control structure, its control loop mainly includes the power loop, power calculation link, AC voltage and current double closed loop, virtual inductance control and other links. The satisfied state space equation is derived as follows:

[0042] The power loop simulates the operating characteristics of the synchronous generator and includes active loop and reactive loop structures, which satisfy the following equation:

[0043]

[0044] Where ω and θ GFM The electrical angular velocity and electrical angle, J and D, constructed for the active loop p are the virtual inertia and droop coefficient of the active loop; K and D q is the inertia coefficient and droop coefficient of the reactive loop; E is the VSG reference voltage amplitude output by the reactive loop; U ref , U are the reference value and actual value of the grid connection point voltage; P, Q, P ref , Q ref are the actual value and given value of system active power and reactive power respectively; K i1 is the reactive loop integral coefficient, and △ represents the small disturbance of the variable.

[0045] The calculation expression of system active and reactive power is shown in formula (2):

[0046]

[0047] Where, ω l is the cutoff frequency of the first-order low-pass filter. P and Q are the state variables of active power and reactive power introduced by the low-pass filter. d , I q 、U d、U q for i d 、i q 、u d 、u q The steady-state value of u d 、u q 、i d 、i q are the dq-axis components of the grid-connected point voltage and grid-connected current;

[0048] The voltage and current inner loop of the grid-type converter adopts a PI controller, a decoupling and feedforward combined control method. According to its control block diagram, it has a total of 4 PI links. The state variables are taken after each integral link, and a total of four state variables Ф are introduced. d , Ф q , ψ d , ψ q The state space equation satisfied by the voltage and current double closed loop with the introduction of steady-state virtual inductance is shown in equation (3):

[0049]

[0050] Where i ldref 、i lqref are the given values of the dq axis current of the current inner loop output by the AC voltage loop, L v is the virtual inductance value. The superscript c represents the variable expressed in the control coordinate system corresponding to the active loop output angle. d 、φ q , ψ d , ψ q is an intermediate variable;

[0051] By arranging the above equations, the state space model of the wind power grid-connected unit under grid-type control can be obtained as follows:

[0052]

[0053] Δy=CΔx (5)

[0054] Where Δx is the state variable of the wind power grid-connected unit under grid-type control, △x=[△ω,△θ GFM , △E, △P, △Q, △Ф d , △Ф q , △ψ d , △ψ q ,△i ld , △i lq , △u d , △u q ,△i d ,△i q ], Δu is the input variable, Δu=[Δu gD ;ΔugQ ], Δy is the output variable, Δy=[△i d ,△i q ], A, B, and C are the state matrix, input matrix, and output matrix of the state space model respectively.

[0055] In addition, the resistive-inductive power grid line satisfies the following state space equation:

[0056]

[0057] Where, L g 、R g They are the equivalent inductance and equivalent resistance of the power grid line, u gd 、u gq is the dq axis component of the grid voltage, ω n Indicates the grid frequency rating.

[0058] In summary, the small signal state space model of grid-connected wind turbines and grid-connected lines under grid-type control can be obtained.

[0059] S2. Based on the established state-space model, solve the characteristic roots of each mode of the system. Use tools such as root loci and participation factors to determine the impact of various factors on the medium-frequency oscillation of the system. Study the dominant factors of the medium-frequency oscillation caused by the network-type control. The specific steps are as follows:

[0060] Based on the model of the grid-type converter, the characteristic matrix A can be used to obtain the characteristic roots of each mode, satisfying the following equation:

[0061] det(A-λ i I)=0 (8)

[0062] Where λ i is the modal characteristic root of the system, λ i =a i +jb i , a i 、b i denote the real and imaginary parts of the characteristic roots respectively;

[0063] Then, using matrix calculation derivation, the participation factor of each state variable to each modal eigenvalue can be obtained, satisfying the equations shown in equations (9)-(10):

[0064] Av i =λ i v i (9)

[0065]

[0066] Where, v i is the right eigenvector of the i-th eigenvalue of the system, ui is the left eigenvector of the i-th eigenvalue of the system, γ i is the participation factor of the i-th characteristic root of the system.

[0067] Using the above-mentioned eigenvalue analysis method, we can calculate the dominant participating variables of the characteristic roots of the system's medium-frequency oscillation mode, plot the root loci of the dominant oscillation mode as the virtual inductance and other control parameters change, and use the damping ratio curve of the system's dominant mode as the parameters change to clarify the dominant role of the virtual inductance in the medium-frequency oscillation of the network-type control. The damping ratio is calculated from the characteristic roots, as shown in Equation (11).

[0068]

[0069] Where, ξ i is the damping ratio of the i-th eigenvalue.

[0070] refer to Figure 3 , adjust the virtual inductance L in the grid-connected system v The parameter increases from 0.01pu to 0.2pu. The root loci of the low-frequency characteristic roots and the intermediate-frequency characteristic roots of the system are as follows: Figure 3 As shown in the figure, it can be seen that as the virtual inductance increases, the low-frequency stability is improved, but it will reduce the system's medium-frequency stability and cause the system to oscillate at medium frequencies. Furthermore, the influence of the short-circuit ratio change, the voltage loop proportional coefficient change, and the current loop parameter change on the system's medium-frequency modal damping ratio under different virtual inductance values can be plotted as follows: Figures 4 to 6 As shown in the figure. It can be seen that the introduction of virtual inductance into the system reduces the damping ratio of the system's mid-frequency modes. As the virtual inductance value and short-circuit ratio increase, the characteristic modes exhibit negative damping characteristics, and the system becomes unstable. Similarly, when virtual inductance is not introduced, even when the voltage loop proportional coefficient varies widely, the system can still maintain a certain positive damping ratio and remain stable in the mid-frequency band. When virtual inductance is not introduced, even when the current loop proportional and integral coefficients vary widely, the system can still maintain a certain positive damping ratio and remain stable in the mid-frequency band. In summary, the mid-frequency oscillation of the grid-type converter is dominated by the increase in steady-state virtual inductance.

[0071] Based on the above derivation Figure 2 Improvement of the AC voltage and current double closed loop:

[0072] S3. Sample the current value of the grid-connected line and obtain the dq-axis components of the grid-connected current in the rotating coordinate system according to the coordinate transformation:

[0073] The three-phase current value i on the converter grid-connected line is sampled by the sensor abc , the three-phase current i is converted to abc Converted to the two-phase stationary coordinate system, the current value i is obtained α 、iβ , and then transform the variables in the stationary coordinate system into the dq rotating coordinate system through Park transformation to obtain the dq axis component of the grid-connected current i d 、i q .

[0074] S4, the dq axis components of the grid current in the rotating coordinate system multiplied by the virtual inductance L v The differential term after the first-order low-pass filter is used to obtain the dynamic virtual inductance term of the dq axis in the rotating coordinate system, and the dynamic virtual inductance term is introduced into the AC voltage loop input end of the AC voltage and current double closed loop:

[0075] In order to simulate the effect of actual line inductance in the full frequency band, the dynamic characteristics of the virtual inductor are taken into account and the dynamic behavior of the inductor is simulated by making the output voltage proportional to the derivative of the output current. The specific changes are: based on the steady-state algebraic virtual inductor, a current differential term multiplied by the virtual inductor is introduced. However, since the pure differential term will lead to the accumulation of deviations and may amplify high-frequency noise, a first-order high-pass filter term is used to replace the pure differential term, which is equivalent to constructing a differential term with a low-pass filter. Its control structure is as follows: Figure 7 shown.

[0076] The dq-axis components of the grid-connected line current pass through the differential term, and the relationship between the variables is shown in formula (12):

[0077]

[0078] Where, and It is the variable after differentiation of the dq-axis component of the grid-connected current.

[0079] According to the proposed control structure, the current differential term needs to be introduced into the input port of the AC voltage loop after passing through a low-pass filter, and it satisfies the equation shown in equation (13):

[0080]

[0081] Where L1 and L2 are the dynamic virtual inductance terms of the dq axis in the rotating coordinate system, ω cc is the cutoff frequency of the low-pass filter, s represents the Laplace operator,

[0082] After introducing the improved control, the new state space equation satisfied by the AC voltage loop of the network control can be further derived as follows:

[0083]

[0084] Where R v is the virtual resistance value, and the dq axis virtual input voltages at the AC voltage loop input end of the grid-type converter are Ed and E q , ΔE d =ΔE-ΔL1-R v Δi d , ΔE q =-ΔL2-R v Δi q , R v represents the virtual resistance value, and E is the VSG reference voltage amplitude output by the reactive power control loop.

[0085] like Figure 7 As shown in Figure 2, the control equation of the AC voltage and current double closed loop with the introduction of virtual inductance is:

[0086]

[0087] Among them, i ld 、i lq are the dq axis components of the filter inductor current respectively; d 、φ q , ψ d , ψ q is the intermediate variable, K pV , K iV is the PI control parameter of the voltage loop, K pi , K ii is the PI control parameter of the current loop, L f 、C f Represents filter inductance and filter capacitance, e d 、e q They respectively represent the dq axis components of the converter output voltage reference value.

[0088] Specifically, refer to Figure 8 After the improved control is introduced into the grid-type converter, the trajectory curve of the system's mid-frequency characteristic roots as the virtual inductance parameters increase shows that the system's mid-frequency characteristic roots no longer move to the right half plane, the system always remains stable, and mid-frequency oscillation no longer occurs due to the increase of virtual inductance, verifying the effectiveness of the improved control.

[0089] refer to Figure 9 、 Figure 10 , which is the experimental waveform diagram of suppressing the system frequency oscillation after the dynamic virtual inductance control method is introduced into the grid-type converter, as shown in Figure 9 、 10 The following experimental waveforms show improved control using dynamic virtual inductance when the current loop proportional coefficient and virtual inductance increase, and when the system experiences intermediate-frequency oscillations. These waveforms demonstrate that improved control using dynamic virtual inductance rapidly suppresses system oscillations, shortens the dynamic process, and minimizes power fluctuations. After recovery, the system current maintains high current stability and sinusoidality, effectively improving the intermediate-frequency stability of the grid-connected converter.

[0090] This embodiment also provides a control device for improving the broadband oscillation stability of a grid-type converter, including an active and reactive power control device and an AC voltage and current control device;

[0091] Active and reactive power control device, used to obtain VSG reference voltage amplitude by using active and reactive power control loop, and input it to AC voltage and current control device;

[0092] The AC voltage and current control device is used to obtain the converter output voltage reference value based on the received VSG reference voltage amplitude and the AC voltage and current double closed loop with the virtual inductor introduced, and then obtain the PWM modulation wave instruction. v The AC voltage and current double closed loop method is:

[0093] The current value of the grid-connected line is sampled, and the dq axis components of the grid-connected current in the rotating coordinate system are obtained according to the coordinate transformation; the dq axis components of the grid-connected current in the rotating coordinate system are multiplied by the virtual inductance L v The differential term after the transformation is passed through a first-order low-pass filter to obtain the dynamic virtual inductance term of the dq axis in the rotating coordinate system, and the dynamic virtual inductance term is introduced into the AC voltage loop input end of the AC voltage and current double closed loop.

[0094] The control equation of the AC voltage and current double closed loop with the introduction of virtual inductance is:

[0095]

[0096] Among them, u d 、u q are the dq axis components of the grid connection point voltage, ω n is the grid frequency rating, i ldref 、i lqref are the given values of the dq axis current of the current loop output by the AC voltage loop; i ld 、i lq are the dq axis components of the filter inductor current respectively; d 、φ q , ψ d , ψ q is the intermediate variable, K pV , K iV is the PI control parameter of the voltage loop, K pi , K ii is the PI control parameter of the current loop, L f 、C f Represents filter inductance and filter capacitance, e d 、e q They represent the dq axis components of the converter output voltage reference value respectively. The superscript c indicates that the variable is expressed in the control coordinate system corresponding to the output angle of the active control loop.

[0097] The dq axis virtual input voltages at the input end of the AC voltage loop of the grid-type converter are E d and E q , ΔE d =ΔE-ΔL1-R v Δi d , ΔE q =-ΔL2-R v Δi q , E is the VSG reference voltage amplitude output by the reactive control loop, △ represents the small disturbance of the corresponding variable, R v Indicates the virtual resistance value; the dq axis components of the grid current in the rotating coordinate system are i d and i q ;

[0098] The dynamic virtual inductance terms of the dq axis in the rotating coordinate system are L1 and L2 respectively. s represents the Laplace operator, ω cc is the cutoff frequency of the low-pass filter.

[0099] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A control method for improving the broadband oscillation stability of a grid-type converter, characterized in that: include: The grid-type converter adopts virtual synchronous control, including active and reactive power control loops and AC voltage and current double closed loops; The VSG reference voltage amplitude is obtained according to the active and reactive power control loop, and then the converter output voltage reference value is obtained by combining the AC voltage and current double closed loop with the introduction of virtual inductance, and then the PWM modulation wave instruction is obtained. Among them, the virtual inductance L is introduced. v The AC voltage and current double closed loop method is: Sampling the current value of the grid-connected line, and obtaining the dq-axis components of the grid-connected current in the rotating coordinate system according to coordinate transformation; The dq axis components of the grid current in the rotating coordinate system are multiplied by the virtual inductance L v The differential term after the transformation is passed through a first-order low-pass filter to obtain the dynamic virtual inductance term of the dq axis in the rotating coordinate system, and the dynamic virtual inductance term is introduced into the AC voltage loop input end of the AC voltage and current double closed loop.

2. The control method for improving broadband oscillation stability of a grid-type converter according to claim 1, characterized in that: The dq axis components of the grid-connected current in the rotating coordinate system are i d and i q ; The dynamic virtual inductance terms of the dq axes in the rotating coordinate system are L1 and L2 respectively; Where s represents the Laplace operator, ω cc is the cutoff frequency of the first-order low-pass filter.

3. The control method for improving broadband oscillation stability of a grid-type converter according to claim 1, characterized in that: The dynamic virtual inductance term is introduced into the AC voltage loop input of the grid-type converter, including: The dq axis virtual input voltages at the input end of the AC voltage loop of the grid-type converter are E d and E q : D.E. d =ΔE-ΔL1-R v Yes d D.E. q =-ΔL2-R v Yes q Where E is the VSG reference voltage amplitude output by the reactive control loop, △ represents the small disturbance of the corresponding variable, R v Indicates the virtual resistance value.

4. The control method for improving broadband oscillation stability of a grid-type converter according to claim 1, characterized in that: The control equation of the AC voltage and current double closed loop with the introduction of virtual inductance is: Among them, u d 、u q are the dq axis components of the grid connection point voltage, ω n is the grid frequency rating, i ldref 、i lqref are the given values of the dq axis current of the current loop output by the AC voltage loop; i ld 、i lq are the dq axis components of the filter inductor current respectively; φ d 、φ q , ψ d , ψ q is the intermediate variable, K pV , K iV is the PI control parameter of the voltage loop, K pi , K ii is the PI control parameter of the current loop, L f 、C f Represents filter inductance and filter capacitance, e d 、e q They represent the dq-axis components of the converter output voltage reference value respectively. The superscript c indicates that the variable is expressed in the control coordinate system corresponding to the output angle of the active control loop.

5. A computer-readable storage device storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the control method for improving the broadband oscillation stability of a grid-type converter are implemented as claimed in any one of claims 1 to 4.

6. A control device for improving the broadband oscillation stability of a grid-type converter, comprising a storage device, a processor, and a computer program stored in the storage device and executable on the processor, characterized in that: The processor executes the computer program to implement the steps of the disk satellite mass moment attitude control method according to any one of claims 1 to 4.

7. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the control method for improving the broadband oscillation stability of a grid-type converter are implemented as claimed in any one of claims 1 to 4.

8. A control device for improving the broadband oscillation stability of a grid-type converter, characterized in that: Including active and reactive power control device and AC voltage and current control device; Active and reactive power control device, used to obtain VSG reference voltage amplitude by using active and reactive power control loop, and input it to AC voltage and current control device; The AC voltage and current control device is used to obtain the converter output voltage reference value based on the received VSG reference voltage amplitude and the AC voltage and current double closed loop with the virtual inductor introduced, and then obtain the PWM modulation wave instruction. v The AC voltage and current double closed loop method is: The current value of the grid-connected line is sampled, and the dq axis components of the grid-connected current in the rotating coordinate system are obtained according to the coordinate transformation; the dq axis components of the grid-connected current in the rotating coordinate system are multiplied by the virtual inductance L v The differential term after the transformation is passed through a first-order low-pass filter to obtain the dynamic virtual inductance term of the dq axis in the rotating coordinate system, and the dynamic virtual inductance term is introduced into the AC voltage loop input end of the AC voltage and current double closed loop.

9. The control device for improving broadband oscillation stability of a grid-type converter according to claim 8, characterized in that: The control equation of the AC voltage and current double closed loop with the introduction of virtual inductance is: Among them, u d 、u q are the dq axis components of the grid connection point voltage, ω n is the grid frequency rating, i ldref 、i lqref are the given values of the dq axis current of the current loop output by the AC voltage loop; i ld 、i lq are the dq axis components of the filter inductor current respectively; φ d 、φ q , ψ d , ψ q is the intermediate variable, K pV , K iV is the PI control parameter of the voltage loop, K pi , K ii is the PI control parameter of the current loop, L f 、C f Represents filter inductance and filter capacitance, e d 、e q They represent the dq axis components of the converter output voltage reference value respectively. The superscript c indicates that the variable is expressed in the control coordinate system corresponding to the output angle of the active control loop. The dq axis virtual input voltages at the input end of the AC voltage loop of the grid-type converter are E d and E q : D.E. d =ΔE-ΔL1-R v Yes d D.E. q =-ΔL2-R v Yes q Where E is the VSG reference voltage amplitude output by the reactive control loop, △ represents the small disturbance of the corresponding variable, R v Indicates the virtual resistance value; the dq axis components of the grid current in the rotating coordinate system are i d and i q The dynamic virtual inductance terms of the dq axes in the rotating coordinate system are L1 and L2 respectively; Where s represents the Laplace operator, ω cc is the cutoff frequency of the first-order low-pass filter.

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