Method and device for setting control parameters of networked converter

Abstract

This application discloses a method and apparatus for tuning control parameters of a grid-type converter. The method includes: solving the closed-loop transfer function of the first current control loop; using the Routh criterion to obtain the inequality constraints that the active power-frequency outer loop control parameters should satisfy under preset stability requirements; solving the inequality constraints under preset dynamic performance requirements to tune the active power-frequency outer loop control parameters; solving the closed-loop transfer function of the second current control loop to tune the reactive power-voltage outer loop control parameters; determining the parameter selection range of virtual inductance and virtual resistance based on the converter inductance to tune the virtual impedance control parameters; and solving the closed-loop transfer function of the third current control loop to solve the equality constraints that the current inner loop control parameters should satisfy under preset dynamic performance requirements to tune the current inner loop control parameters. This solves the technical problems in related technologies where parameter tuning based on experience or trial and error is inefficient and makes it difficult to find optimal control parameters.

Description

Technical Field

[0001] This application relates to the field of power system analysis and control technology, and in particular to a method and device for tuning control parameters of a grid-type converter. Background Technology

[0002] Power systems exhibit a clear "high proportion of power electronics" characteristic on the transmission, distribution, and consumption sides. Grid connection strategies for power electronic converters are generally divided into two types: grid-following and grid-connecting. Among them, the grid-following control strategy was proposed earlier and is the most widely used in power systems. However, grid-following control relies on phase-locked loops to track the grid voltage phase, which can easily lead to electromagnetic oscillations under weak grid conditions; moreover, grid-following control does not possess the inertial characteristics of traditional synchronous generator units.

[0003] To address the aforementioned issues, some studies have proposed grid-based control strategies. These strategies do not rely on phase-locked loops (PLLs), can establish voltage and frequency independently, and exhibit good stability even in weak power grids. A typical grid-based control strategy is virtual synchronous machine control, which simulates the rotor motion equations of a traditional synchronous machine.

[0004] Currently, research on grid-type converters mainly focuses on analyzing and improving their control performance, while research on parameter tuning is relatively limited. In related technologies, parameter tuning can be performed based on experience or trial and error, which not only has low tuning efficiency but also makes it difficult to find the optimal control parameters, failing to achieve a balance between stability and dynamic control performance, and thus needs improvement. Summary of the Invention

[0005] This application provides a method and apparatus for tuning control parameters of a grid-type converter to solve the technical problems in related technologies where parameter tuning is based on experience or trial and error, resulting in low tuning efficiency and difficulty in finding optimal control parameters to achieve both stability and dynamic control performance.

[0006] The first aspect of this application provides a method for tuning control parameters of a grid-type converter, comprising the following steps: solving the closed-loop transfer function of a first current control loop, and using the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under a preset stability requirement; solving the inequality constraints that the active-frequency outer loop control parameters should satisfy under a preset dynamic performance requirement, thereby tuning the active-frequency outer loop control parameters; solving the closed-loop transfer function of a second current control loop, and using the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirement. The reactive power-voltage outer loop control parameters should satisfy inequality constraints to tune the reactive power-voltage outer loop control parameters; the parameter selection range of virtual inductance and virtual resistance should be determined based on the converter inductance to tune the virtual impedance control parameters; and the closed-loop transfer function of the third current control loop should be solved, and the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements should be obtained using the Routh criterion, and the equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements should be solved to tune the current inner loop control parameters.

[0007] Optionally, in one embodiment of this application, the closed-loop transfer function of the first current control loop is:

[0008]

[0009] Where U is the converter output voltage, E q T is the output voltage of the converter switching devices. J D is the equivalent inertial time constant. p K is the first damping coefficient. f X is the frequency modulation effect coefficient. s Let be the total reactance of the converter, and s be the Laplace operator.

[0010] Optionally, in one embodiment of this application, the inequality constraints that the active-frequency outer loop control parameters should satisfy include:

[0011] First stability constraint:

[0012]

[0013] And, the first dynamic performance constraint:

[0014]

[0015] Where ζ is the second damping coefficient.

[0016] Optionally, in one embodiment of this application, the closed-loop transfer function of the second current control loop is:

[0017]

[0018] Among them, K pQ and K iQ The proportional and integral gains of the PI element in the reactive power-voltage outer loop control are given.

[0019] Optionally, in one embodiment of this application, the second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is:

[0020]

[0021] Optionally, in one embodiment of this application, the closed-loop transfer function of the third current control loop is:

[0022]

[0023]

[0024] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0025] Optionally, in one embodiment of this application, the equality constraints that the current inner loop control parameters should satisfy include:

[0026] Third stability constraint:

[0027]

[0028] And, the second dynamic performance constraint:

[0029]

[0030] A second aspect of this application provides a control parameter tuning device for a grid-type converter, comprising: a first calculation module, used to solve the closed-loop transfer function of a first current control loop, and using the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under a preset stability requirement, and to solve the inequality constraints that the active-frequency outer loop control parameters should satisfy under a preset dynamic performance requirement, so as to tune the active-frequency outer loop control parameters; and a second calculation module, used to solve the closed-loop transfer function of a second current control loop, and using the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirement. The system comprises: a power-voltage outer loop control parameter set to satisfy inequality constraints to tune the power-voltage outer loop control parameters; a determination module to determine the parameter selection range of virtual inductance and virtual resistance based on the converter inductance to tune the virtual impedance control parameters; and a third calculation module to solve the closed-loop transfer function of the third current control loop, and to use the Routh criterion to obtain the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements, and to solve the equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements to tune the current inner loop control parameters.

[0031] Optionally, in one embodiment of this application, the closed-loop transfer function of the first current control loop is:

[0032]

[0033] Where U is the converter output voltage, E q T is the output voltage of the converter switching devices. J D is the equivalent inertial time constant. p K is the first damping coefficient. f X is the frequency modulation effect coefficient. s Let be the total reactance of the converter, and s be the Laplace operator.

[0034] Optionally, in one embodiment of this application, the inequality constraints that the active-frequency outer loop control parameters should satisfy include:

[0035] First stability constraint:

[0036]

[0037] And, the first dynamic performance constraint:

[0038]

[0039] Where ζ is the second damping coefficient.

[0040] Optionally, in one embodiment of this application, the closed-loop transfer function of the second current control loop is:

[0041]

[0042] Among them, K pQ and K iQ The proportional and integral gains of the PI element in the reactive power-voltage outer loop control are given.

[0043] Optionally, in one embodiment of this application, the second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is:

[0044]

[0045] Optionally, in one embodiment of this application, the closed-loop transfer function of the third current control loop is:

[0046]

[0047]

[0048] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0049] Optionally, in one embodiment of this application, the equality constraints that the current inner loop control parameters should satisfy include:

[0050] Third stability constraint:

[0051]

[0052] And, the second dynamic performance constraint:

[0053]

[0054] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the grid-type converter control parameter tuning method as described in the above embodiments.

[0055] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for tuning control parameters of a grid-type converter.

[0056] This application's embodiments can simulate the mechanical and electromagnetic components of a synchronous generator, enabling the converter to possess the inertial damping characteristics of a synchronous generator. Through active-frequency outer loop control parameter tuning, reactive-voltage outer loop control parameter tuning, virtual impedance control parameter tuning, and current inner loop control parameter tuning, the overall dynamic performance of the control loop is improved as much as possible while meeting stability requirements, thus increasing tuning efficiency. This solves the technical problems in related technologies where parameter tuning based on experience or trial and error results in low tuning efficiency and difficulty in finding optimal control parameters to achieve a balance between stability and dynamic control performance.

[0057] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0058] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0059] Figure 1 This is a flowchart of a method for tuning control parameters of a grid-type converter according to an embodiment of this application;

[0060] Figure 2 This is a schematic diagram illustrating the principle of a grid-type converter control parameter tuning method according to an embodiment of this application;

[0061] Figure 3 This is a flowchart of a method for tuning control parameters of a grid-type converter according to an embodiment of this application;

[0062] Figure 4 This is a schematic diagram of a grid-type converter control parameter tuning device provided according to an embodiment of this application;

[0063] Figure 5 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0064] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0065] The following description, with reference to the accompanying drawings, illustrates a method and apparatus for tuning control parameters of a grid-type converter according to embodiments of this application. Addressing the technical problems mentioned in the background section, where parameter tuning based on experience or trial and error results in low tuning efficiency and difficulty in finding optimal control parameters to achieve a balance between stability and dynamic control performance, this application provides a method for tuning control parameters of a grid-type converter. In this method, the mechanical and electromagnetic components of a synchronous generator are simulated to give the converter the inertial damping characteristics of a synchronous generator. Through active power-frequency outer loop control parameter tuning, reactive power-voltage outer loop control parameter tuning, virtual impedance control parameter tuning, and current inner loop control parameter tuning, the overall dynamic performance of the control loop is improved as much as possible while meeting stability requirements, thus increasing tuning efficiency. Therefore, this solves the technical problems in related technologies where parameter tuning based on experience or trial and error results in low tuning efficiency and difficulty in finding optimal control parameters to achieve a balance between stability and dynamic control performance.

[0066] Specifically, Figure 1 This is a flowchart illustrating a method for tuning control parameters of a grid-type converter, as provided in an embodiment of this application.

[0067] like Figure 1 As shown, the method for tuning the control parameters of this grid-type converter includes the following steps:

[0068] In step S101, the closed-loop transfer function of the first current control loop is solved, and the Routh criterion is used to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirements. The inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset dynamic performance requirements are solved to tune the active-frequency outer loop control parameters.

[0069] In actual implementation, the embodiments of this application can solve the closed-loop transfer function of the first current control loop, and then use the Routh criterion to obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements, thereby solving the inequality constraints that the control parameters should satisfy under the dynamic performance requirements, and thus achieving the tuning of the active-frequency outer loop control parameters under the premise of satisfying stability.

[0070] The preset stability requirements will be explained below.

[0071] Optionally, in one embodiment of this application, the closed-loop transfer function of the first current control loop is:

[0072]

[0073] Where U is the converter output voltage, E q T is the output voltage of the converter switching devices. J D is the equivalent inertial time constant.p K is the first damping coefficient. f X is the frequency modulation effect coefficient. s Let be the total reactance of the converter, and s be the Laplace operator.

[0074] Specifically, in the embodiments of this application, it can be assumed that the output resistance of the converter is much smaller than the reactance, that is, the resistance value can be ignored, and the total reactance of the converter can be X. s (Considering both actual and virtual impedance), the active power P output by the converter can be:

[0075]

[0076] Where U is the converter output voltage, E q δ is the output voltage of the converter switching device, and δ is the phase angle difference between the two voltages.

[0077] Based on the transfer function of the active-frequency outer loop control, the embodiments of this application yield the following:

[0078]

[0079] Among them, T J D p and K f These are the equivalent inertial time constant, the first damping coefficient, and the frequency adjustment effect coefficient, respectively.

[0080] For active-frequency control, its open-loop transfer function can be:

[0081]

[0082] The closed-loop transfer function of the first current control loop can be:

[0083]

[0084] Optionally, in one embodiment of this application, the inequality constraints that the active-frequency outer loop control parameters should satisfy include:

[0085] First stability constraint:

[0086]

[0087] And, the first dynamic performance constraint:

[0088]

[0089] Where ζ is the second damping coefficient.

[0090] Considering system stability, i.e., the poles of the closed-loop transfer function must all be distributed in the left half of the complex plane, the embodiments of this application can be based on the Routh criterion:

[0091]

[0092] Among them, X s , U and E q If all parameters are positive, the inequality can be further simplified to the first stability constraint:

[0093]

[0094] Considering its dynamic performance, the above transfer function is a typical second-order transfer function, and the second damping coefficient ζ can be:

[0095]

[0096] During parameter tuning, to improve the dynamic performance of the control loop and reduce overshoot, the embodiments of this application can set the second damping coefficient ζ to be between 0.4 and 0.8, that is, the first dynamic performance constraint is:

[0097]

[0098] In summary, under the stability requirement, the active power-frequency outer loop control parameters must satisfy the first stability constraint of the inequality; to ensure the dynamic performance of the control loop, the control parameters must also satisfy the first dynamic performance constraint of the inequality.

[0099] In step S102, the closed-loop transfer function of the second current control loop is solved, and the Routh criterion is used to obtain the inequality constraints that the reactive power-voltage outer loop control parameters should satisfy under the preset stability requirements, so as to tune the reactive power-voltage outer loop control parameters.

[0100] As one possible approach, embodiments of this application can solve the closed-loop transfer function of the second current control loop, and then use the Routh criterion to obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements, thereby achieving the tuning of the reactive power-voltage outer loop control parameters while satisfying stability.

[0101] The preset stability requirements will be explained below.

[0102] Optionally, in one embodiment of this application, the closed-loop transfer function of the second current control loop is:

[0103]

[0104] Among them, K pQ and K iQ The proportional and integral gains of the PI element in the reactive power-voltage outer loop control are given.

[0105] Specifically, the reactive power Q output by the converter can be:

[0106]

[0107] Where U is the converter output voltage, E q X is the output voltage of the converter switching devices. s This refers to the output reactance of the converter.

[0108] Considering reactive power-voltage control, the voltage deviation ΔE can be obtained from the embodiments of this application:

[0109]

[0110] Among them, K pQ and K iQ ΔQ represents the proportional and integral gains of the PI element in the reactive power-voltage outer loop control, and ΔQ represents the reactive power disturbance component.

[0111] For the reactive power-voltage control loop, i.e., the second current control loop, the closed-loop transfer function is:

[0112]

[0113] Optionally, in one embodiment of this application, the second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is:

[0114]

[0115] In practical implementation, considering system stability, this embodiment of the application may require all closed-loop poles to be distributed in the left half-plane of the complex plane. According to the Routh criterion:

[0116]

[0117] Among them, X s If both the parameter U and the parameter are positive, then the inequality can be further simplified to:

[0118]

[0119] Considering its dynamic performance, since the open-loop transfer function of the reactive power-voltage control loop is a typical first-order transfer function and there is no obvious overshoot component, the control parameters in this embodiment do not need to satisfy the other constraints.

[0120] In summary, the reactive power-voltage outer loop control parameters must satisfy the above inequality constraints under the requirements of stability and dynamic performance.

[0121] In step S103, the parameter selection range of virtual inductance and virtual resistance is determined based on the converter inductance in order to adjust the virtual impedance control parameters.

[0122] Understandably, the function of virtual impedance control is equivalent to connecting an equivalent impedance in series at the output port of the converter, allowing for flexible adjustment of the converter's output impedance.

[0123] In this embodiment, the virtual inductance L can be determined based on the converter inductance L. V and virtual resistance R V The range of parameters to be selected.

[0124] Among these, to meet stability requirements and improve the dynamic performance of the control circuit, the virtual inductance L... V The virtual resistance R can be on the same order of magnitude as the converter inductance L. V It can be L V 10%.

[0125] In step S104, the closed-loop transfer function of the third current control loop is solved, and the Routh criterion is used to obtain the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements. The equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements are solved to tune the current inner loop control parameters.

[0126] In some embodiments, the embodiments of this application can solve the closed-loop transfer function of the third current control loop, obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements using the Routh criterion, and solve the equality constraints that the control parameters should satisfy under the preset dynamic performance requirements, thereby achieving the tuning of the current inner loop control parameters under the premise of satisfying stability.

[0127] The preset stability requirements and preset dynamic performance requirements will be explained below.

[0128] Optionally, in one embodiment of this application, the closed-loop transfer function of the third current control loop is:

[0129]

[0130]

[0131] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0132] Specifically, when designing the current closed-loop parameters, the embodiments of this application can assume that the d-axis and q-axis controls are decoupled, and the open-loop transfer function H of the current controller... i,d (s) and H i,q(s) can be defined as follows:

[0133]

[0134]

[0135] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0136] Then the closed-loop transfer function of the third current control loop is:

[0137]

[0138]

[0139] Optionally, in one embodiment of this application, the equality constraints that the current inner loop control parameters should satisfy include:

[0140] Third stability constraint:

[0141]

[0142] And, the second dynamic performance constraint:

[0143]

[0144] Furthermore, considering system stability, it is required that all closed-loop poles are distributed in the left half-plane of the complex plane. According to the Routh criterion in this embodiment, the following is true:

[0145]

[0146]

[0147] Obviously, for the above equation, all parameters are positive, and the first four inequalities hold. In this embodiment, only the last inequality needs to be satisfied to meet the stability requirements of the parameter design. Usually, R is very small, so the inequalities can be further simplified to a third stability constraint:

[0148]

[0149] Based on the principles of automatic control, in order to improve the dynamic performance of the control system, this application embodiment can attempt to make the poles of the closed-loop transfer function compensate for the zeros, that is, to make the zeros closer to the poles.

[0150] Therefore, the active power-frequency control parameters can satisfy the second dynamic performance constraint:

[0151]

[0152] In summary, under the stability requirement, the current inner loop control parameters must satisfy the third stability constraint of the inequality; to ensure the dynamic performance of the control loop, the current inner loop control parameters must also satisfy the second dynamic performance constraint of the equation.

[0153] It should be understood that steps S101 and S104 are set only for the convenience of description and are not intended to restrict the execution order of the methods.

[0154] Combination Figure 2 and Figure 3 As shown, the working principle of the grid-type converter control parameter tuning method of this application is explained in detail with an embodiment.

[0155] like Figure 2 The diagram shows the strategy and control parameters for setting the control parameters of a grid-type converter according to an embodiment of this application. It can include four parts: active power-frequency outer loop control, reactive power-voltage outer loop control, virtual impedance control, and current inner loop control.

[0156] like Figure 3 As shown, embodiments of this application may include the following steps:

[0157] Step S301: Set the active power-frequency outer loop control parameters.

[0158] In actual implementation, the embodiments of this application can solve the closed-loop transfer function of the first current control loop, and then use the Routh criterion to obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements, thereby solving the inequality constraints that the control parameters should satisfy under the dynamic performance requirements, and thus achieving the tuning of the active-frequency outer loop control parameters under the premise of satisfying stability.

[0159] The preset stability requirements will be explained below.

[0160] Specifically, in the embodiments of this application, it can be assumed that the output resistance of the converter is much smaller than the reactance, that is, the resistance value can be ignored, and the total reactance of the converter can be X. s (Considering both actual and virtual impedance), the active power P output by the converter can be:

[0161]

[0162] Where U is the converter output voltage, E q δ is the output voltage of the converter switching device, and δ is the phase angle difference between the two voltages.

[0163] Based on the transfer function of the active-frequency outer loop control, the embodiments of this application yield the following:

[0164]

[0165] Among them, T J D p and K f These are the equivalent inertial time constant, the first damping coefficient, and the frequency adjustment effect coefficient, respectively.

[0166] For active-frequency control, its open-loop transfer function can be:

[0167]

[0168] The closed-loop transfer function of the first current control loop can be:

[0169]

[0170] Considering system stability, i.e., the poles of the closed-loop transfer function must all be distributed in the left half of the complex plane, the embodiments of this application can be based on the Routh criterion:

[0171]

[0172] Among them, X s , U and E q If all parameters are positive, the inequality can be further simplified to the first stability constraint:

[0173]

[0174] Considering its dynamic performance, the above transfer function is a typical second-order transfer function, and the second damping coefficient ζ can be:

[0175]

[0176] During parameter tuning, to improve the dynamic performance of the control loop and reduce overshoot, the embodiments of this application can set the second damping coefficient ζ to be between 0.4 and 0.8, that is, the first dynamic performance constraint is:

[0177]

[0178] In summary, under stability requirements, the active power-frequency outer loop control parameters must satisfy the first constraint of the inequality; to ensure the dynamic performance of the control loop, the control parameters must also satisfy the second constraint of the inequality.

[0179] Step S302: Set the reactive power-voltage outer loop control parameters.

[0180] As one possible approach, embodiments of this application can solve the closed-loop transfer function of the second current control loop, and then use the Routh criterion to obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements, i.e., the second stability constraints, thereby achieving the tuning of the reactive power-voltage outer loop control parameters under the premise of satisfying stability.

[0181] The preset stability requirements will be explained below.

[0182] Specifically, the reactive power Q output by the converter can be:

[0183]

[0184] Where U is the converter output voltage, E q X is the output voltage of the converter switching devices. s This refers to the output reactance of the converter.

[0185] Considering reactive power-voltage control, the voltage deviation ΔE can be obtained from the embodiments of this application:

[0186]

[0187] Among them, K pQ and K iQ ΔQ represents the proportional and integral gains of the PI element in the reactive power-voltage outer loop control, and ΔQ represents the reactive power disturbance component.

[0188] For the reactive power-voltage control loop, i.e., the second current control loop, the closed-loop transfer function is:

[0189]

[0190] In practical implementation, considering system stability, this embodiment of the application may require all closed-loop poles to be distributed in the left half-plane of the complex plane. According to the Routh criterion:

[0191]

[0192] Among them, X s If both the parameter U and the parameter are positive, then the inequality can be further simplified to:

[0193]

[0194] Considering its dynamic performance, since the open-loop transfer function of the reactive power-voltage control loop is a typical first-order transfer function and there is no obvious overshoot component, the control parameters in this embodiment do not need to satisfy the other constraints.

[0195] In summary, the reactive power-voltage outer loop control parameters must satisfy the above inequality constraints under the requirements of stability and dynamic performance.

[0196] Step S303: Set the virtual impedance control parameters.

[0197] Understandably, the function of virtual impedance control is equivalent to connecting an equivalent impedance in series at the output port of the converter, allowing for flexible adjustment of the converter's output impedance.

[0198] In this embodiment, the virtual inductance L can be determined based on the converter inductance L. V and virtual resistance R V The range of parameters to be selected.

[0199] Among these, to meet stability requirements and improve the dynamic performance of the control circuit, the virtual inductance L... V The virtual resistance R can be on the same order of magnitude as the converter inductance L. V It can be L V 10%.

[0200] Step S304: Set the inner loop control parameters for the current.

[0201] In some embodiments, the embodiments of this application can solve the closed-loop transfer function of the third current control loop, obtain the inequality constraints that the control parameters should satisfy under the preset stability requirements using the Routh criterion, and solve the equality constraints that the control parameters should satisfy under the preset dynamic performance requirements, thereby achieving the tuning of the current inner loop control parameters under the premise of satisfying stability.

[0202] Specifically, when designing the current closed-loop parameters, the embodiments of this application can assume that the d-axis and q-axis controls are decoupled, and the open-loop transfer function H of the current controller... i,d (s) and H i,q (s) can be defined as follows:

[0203]

[0204]

[0205] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0206] Then the closed-loop transfer function of the third current control loop is:

[0207]

[0208]

[0209] Furthermore, considering system stability, it is required that all closed-loop poles are distributed in the left half-plane of the complex plane. According to the Routh criterion in this embodiment, the following is true:

[0210]

[0211]

[0212] Obviously, for the above equation, all parameters are positive, and the first four inequalities hold. In this embodiment, only the last inequality needs to be satisfied to meet the stability requirements of the parameter design. Usually, R is very small, so the inequalities can be further simplified to a third stability constraint:

[0213]

[0214] Based on the principles of automatic control, in order to improve the dynamic performance of the control system, this application embodiment can attempt to make the poles of the closed-loop transfer function compensate for the zeros, that is, to make the zeros closer to the poles.

[0215] Therefore, the active power-frequency control parameters can satisfy the second dynamic performance constraint:

[0216]

[0217] In summary, under the stability requirement, the current inner loop control parameters must satisfy the third stability constraint of the inequality; to ensure the dynamic performance of the control loop, the current inner loop control parameters must also satisfy the second dynamic performance constraint of the equation.

[0218] It should be understood that steps S301 and S304 are set only for the convenience of description and are not intended to restrict the execution order of the methods.

[0219] The grid-type converter control parameter tuning method proposed in this application can simulate the mechanical and electromagnetic parts of a synchronous generator, enabling the converter to possess the inertial damping characteristics of a synchronous generator. Through active power-frequency outer loop control parameter tuning, reactive power-voltage outer loop control parameter tuning, virtual impedance control parameter tuning, and current inner loop control parameter tuning, the overall dynamic performance of the control loop is improved as much as possible while meeting stability requirements, thus increasing tuning efficiency. This solves the technical problems in related technologies where parameter tuning based on experience or trial and error results in low tuning efficiency and difficulty in finding optimal control parameters to achieve a balance between stability and dynamic control performance.

[0220] Next, referring to the accompanying drawings, a control parameter tuning device for a grid-type converter according to an embodiment of this application is described.

[0221] Figure 4This is a block diagram of the control parameter tuning device for a grid-type converter according to an embodiment of this application.

[0222] like Figure 4 As shown, the grid-type converter control parameter tuning device 10 includes: a first calculation module 100, a second calculation module 200, a determination module 300, and a third calculation module 400.

[0223] Specifically, the first calculation module 100 is used to solve the closed-loop transfer function of the first current control loop, and to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirements using the Routh criterion, and to solve the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the active-frequency outer loop control parameters.

[0224] The second calculation module 200 is used to solve the closed-loop transfer function of the second current control loop and use the Routh criterion to obtain the inequality constraints that the reactive power-voltage outer loop control parameters should satisfy under the preset stability requirements, so as to tune the reactive power-voltage outer loop control parameters.

[0225] The determination module 300 is used to determine the parameter selection range of virtual inductance and virtual resistance based on the converter inductance, so as to tune the virtual impedance control parameters.

[0226] The third calculation module 400 is used to solve the closed-loop transfer function of the third current control link, and to obtain the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements using the Routh criterion, and to solve the equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the current inner loop control parameters.

[0227] Optionally, in one embodiment of this application, the closed-loop transfer function of the first current control loop is:

[0228]

[0229] Where U is the converter output voltage, E q T is the output voltage of the converter switching devices. J D is the equivalent inertial time constant. p K is the first damping coefficient. f X is the frequency modulation effect coefficient. s Let be the total reactance of the converter, and s be the Laplace operator.

[0230] Optionally, in one embodiment of this application, the inequality constraints that the active-frequency outer loop control parameters should satisfy include:

[0231] First stability constraint:

[0232]

[0233] And, the first dynamic performance constraint:

[0234]

[0235] Where ζ is the second damping coefficient.

[0236] Optionally, in one embodiment of this application, the closed-loop transfer function of the second current control loop is:

[0237]

[0238] Among them, X pQ and K iQ The proportional and integral gains of the PI element in the reactive power-voltage outer loop control are given.

[0239] Optionally, in one embodiment of this application, the second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is:

[0240]

[0241] Optionally, in one embodiment of this application, the closed-loop transfer function of the third current control loop is:

[0242]

[0243]

[0244] Among them, K pd K id K pq and K iq For the proportional and integral gain of the PI control loop, T d The operating time of the power electronic switch is given by R, and the inductance of the converter is given by R and L, respectively.

[0245] Optionally, in one embodiment of this application, the equality constraints that the current inner loop control parameters should satisfy include:

[0246] Third stability constraint:

[0247]

[0248] And, the second dynamic performance constraint:

[0249]

[0250] It should be noted that the foregoing explanation of the embodiment of the control parameter tuning method for grid-type converters also applies to the control parameter tuning device for grid-type converters in this embodiment, and will not be repeated here.

[0251] The grid-type converter control parameter tuning device proposed in this application can simulate the mechanical and electromagnetic parts of a synchronous generator, enabling the converter to possess the inertial damping characteristics of a synchronous generator. Through active-frequency outer loop control parameter tuning, reactive-voltage outer loop control parameter tuning, virtual impedance control parameter tuning, and current inner loop control parameter tuning, it achieves the best possible overall dynamic performance of the control loop while meeting stability requirements, thus improving tuning efficiency. This solves the technical problems in related technologies where parameter tuning based on experience or trial and error results in low tuning efficiency and difficulty in finding optimal control parameters to achieve a balance between stability and dynamic control performance.

[0252] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include:

[0253] The memory 501, the processor 502, and the computer program stored on the memory 501 and capable of running on the processor 502.

[0254] When the processor 502 executes the program, it implements the control parameter tuning method for the grid-type converter provided in the above embodiments.

[0255] Furthermore, electronic devices also include:

[0256] Communication interface 503 is used for communication between memory 501 and processor 502.

[0257] The memory 501 is used to store computer programs that can run on the processor 502.

[0258] The memory 501 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0259] If the memory 501, processor 502, and communication interface 503 are implemented independently, then the communication interface 503, memory 501, and processor 502 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 5 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0260] Optionally, in a specific implementation, if the memory 501, processor 502, and communication interface 503 are integrated on a single chip, then the memory 501, processor 502, and communication interface 503 can communicate with each other through an internal interface.

[0261] Processor 502 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0262] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for tuning control parameters of a grid-type converter.

[0263] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0264] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0265] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0266] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0267] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0268] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0269] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0270] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for tuning control parameters of a grid-type converter, characterized in that, Includes the following steps: Solve the closed-loop transfer function of the first current control loop, and use the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirements. Solve the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the active-frequency outer loop control parameters. Solve the closed-loop transfer function of the second current control loop, and use the Routh criterion to obtain the inequality constraints that the reactive power-voltage outer loop control parameters should satisfy under the preset stability requirements, so as to tune the reactive power-voltage outer loop control parameters. The parameter selection ranges for virtual inductance and virtual resistance are determined based on the converter inductance to tune the virtual impedance control parameters; and Solve the closed-loop transfer function of the third current control loop, and use the Routh criterion to obtain the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements. Solve the equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the current inner loop control parameters. The closed-loop transfer function of the first current control loop is: ， in, U This is the converter output voltage. The output voltage of the converter switching devices. The equivalent inertial time constant, The first damping coefficient, This is the frequency modulation effect coefficient. For the total reactance of the converter, s For the Laplace operator; The closed-loop transfer function of the second current control loop is: ， in, and The proportional and integral gains of the PI element in the reactive power-voltage outer loop control; The closed-loop transfer function of the third current control loop is: ， ， in, , , and For the proportional and integral gains of the PI control loop, For the operating time of power electronic switches, R and L These are the converter resistor and inductor, respectively.

2. The method according to claim 1, characterized in that, The inequality constraints that the active-frequency outer loop control parameters should satisfy include: First stability constraint: ， And, the first dynamic performance constraint: ， in, This is the second damping coefficient.

3. The method according to claim 1, characterized in that, The second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is: 。 4. The method according to claim 1, characterized in that, The equality constraints that the current inner loop control parameters should satisfy include: Third stability constraint: ； And, the second dynamic performance constraint: 。 5. A control parameter tuning device for a grid-type converter, characterized in that, include: The first calculation module is used to solve the closed-loop transfer function of the first current control loop, and use the Routh criterion to obtain the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset stability requirements, and solve the inequality constraints that the active-frequency outer loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the active-frequency outer loop control parameters. The second calculation module is used to solve the closed-loop transfer function of the second current control loop, and to use the Routh criterion to obtain the inequality constraints that the reactive power-voltage outer loop control parameters should satisfy under the preset stability requirements, so as to tune the reactive power-voltage outer loop control parameters. The determination module is used to determine the parameter selection range of virtual inductance and virtual resistance based on the converter inductance, so as to tune the virtual impedance control parameters; as well as The third calculation module is used to solve the closed-loop transfer function of the third current control loop, and use the Routh criterion to obtain the inequality constraints that the current inner loop control parameters should satisfy under the preset stability requirements, and solve the equality constraints that the current inner loop control parameters should satisfy under the preset dynamic performance requirements, so as to tune the current inner loop control parameters. The closed-loop transfer function of the first current control loop is: ， in, U This is the converter output voltage. The output voltage of the converter switching devices. The equivalent inertial time constant, The first damping coefficient, This is the frequency modulation effect coefficient. For the total reactance of the converter, s For the Laplace operator; The closed-loop transfer function of the second current control loop is: ， in, and The proportional and integral gains of the PI element in the reactive power-voltage outer loop control; The closed-loop transfer function of the third current control loop is: ， ， in, , , and For the proportional and integral gains of the PI control loop, For the operating time of power electronic switches, R and L These are the converter resistor and inductor, respectively.

6. The apparatus according to claim 5, characterized in that, The inequality constraints that the active-frequency outer loop control parameters should satisfy include: First stability constraint: ， And, the first dynamic performance constraint: ， in, This is the second damping coefficient.

7. The apparatus according to claim 5, characterized in that, The second stability constraint that the reactive power-voltage outer loop control parameters should satisfy is: 。 8. The apparatus according to claim 5, characterized in that, The equality constraints that the current inner loop control parameters should satisfy include: Third stability constraint: ； And, the second dynamic performance constraint: 。 9. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the grid-type converter control parameter tuning method as described in any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the control parameter tuning method for a grid-type converter as described in any one of claims 1-4.

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