Converter control method, device and storage medium considering alternating current side phase angle feedback

Abstract

The application discloses a converter control method and device considering AC side phase angle feedback and a storage medium, and belongs to the field of novel power grid formation control. The method comprises the following steps: for a DC-AC power converter, considering the connection of the DC-AC power converter with an infinite bus or a dynamic center inertia (COI) power grid, a converter model containing explicit expressions of energy dynamics, DC links, LC output filters, transmission lines and the like is established, and a closed-loop dynamic equation under a hybrid angle control (HAC) strategy is determined; based on the model and the control strategy, the existence, stability and boundedness of equilibrium points of a closed-loop system are analyzed, and corresponding parameter conditions are given; considering the safety constraints of the power converter, a current limiting control compatible with the hybrid angle control (HAC) is designed, and the stability thereof is analyzed; the implementation method of the hybrid angle control (HAC) in actual application is researched and designed, the robustness thereof is analyzed, behaviors of the hybrid angle control (HAC) under different working conditions are analyzed, and numerical examples are used for verification.

Description

Technical Field

[0001] This application belongs to the field of converter control, specifically relating to converter control methods, devices, and storage media that take into account AC side phase angle feedback. Background Technology

[0002] In recent years, power generation technology has undergone tremendous changes. Currently, converter-interface power generation is gradually replacing large-capacity synchronous motors (SMs), transforming the power system into a low-inertia system. The stability of this transformation is affected by significant inertia reduction, volatility, and potential adverse interactions due to the existence of adjacent time scales.

[0003] To address this issue, existing technologies often employ droop control to simulate the speed droop of a synchronous generator (SG) and control the converter modulation angle proportional to the active power imbalance. However, while controlling the converter modulation angle to be proportional to the active power imbalance can address the active power imbalance to some extent by adjusting the converter modulation angle, its stability and response speed are unsatisfactory when dealing with complex operating conditions.

[0004] Virtual Synchronous Machine (VSM) strategy, as an extension of droop control, simulates the dynamics and control of synchronous generators, but still has limitations in terms of stability and response speed. While Virtual Oscillator Control (VOC) and Scheduling Virtual Oscillator Control (dVOC) have some effect on synchronization, their robustness is insufficient, and they cannot guarantee the stable operation of the system when faced with system disturbances. There is still room for improvement in terms of system stability and response speed.

[0005] I. A search revealed Chinese invention patent CN117728518A, which discloses an autonomous adaptation control method and system for grid-connected converters applicable to power fluctuations. This system includes: a DC subsystem, an AC subsystem, a voltage source converter, and a voltage source converter controller. The DC subsystem includes a DC power supply, a voltage regulator module, and a voltmeter. The AC subsystem includes a large power grid, equivalent inductance, equivalent resistance, filter inductance, filter capacitor, digital energy meter, and PCC point. The voltage source converter controller includes a DC voltage synchronization controller, an active power synchronization controller, a reactive power controller, a voltage control loop, a current control loop, a dq converter, and a PWM modulator. This invention is applicable to power fluctuations caused by new energy generation. It initially regulates the stability of the DC power supply through the voltage regulator module; improves the system's autonomous adaptability by switching the synchronization controller under different states; and reduces current surges and voltage fluctuations during system operation through an improved current control loop control method with voltage signal compensation.

[0006] The technical comparison between this application and the aforementioned prior art documents is as follows:

[0007] 1. The aforementioned comparative document provides a method and system for autonomous adaptation control of grid-connected converters applicable to power fluctuations, which solves the problem of power system instability caused by power fluctuations due to new energy generation, and is mainly aimed at grid-connected converter control in new energy grid-connected scenarios.

[0008] The converter control method, device, and storage medium considering AC side phase angle feedback proposed in this patent belong to the field of novel power grid formation control. It aims to solve the stability problem of low-inertia power systems and realize the stable operation of power converters under different power grid models. It is mainly aimed at converter control in low-inertia power systems.

[0009] The two are fundamentally different in terms of application scenarios and usage background.

[0010] 2. The aforementioned prior art proposes an autonomous adaptive control system for grid-connected converters suitable for power fluctuations, comprising: a DC subsystem, which includes a DC power supply, a voltmeter, and a voltage regulator module connected in sequence, with a capacitor connected in parallel between the DC power supply and the voltmeter; an AC subsystem, which includes a filter inductor, a digital energy meter, an equivalent inductance, and an equivalent resistance connected in series, with the equivalent resistance connected to the main power grid, and a filter capacitor connected in parallel between the filter inductor and the digital energy meter; a voltage source converter, with the voltage regulator module and the filter inductor both connected to it; and a voltage source converter controller, which includes a DC voltage synchronization controller, an active power synchronization controller, a reactive power controller, a voltage control loop, a current control loop, a dq converter, and a PWM modulator, with the reactive power controller connected in series with the voltage control loop and the current control loop, and both the voltage control loop and the current control loop connected in series with the dq converter, the DC voltage synchronization controller and the active power synchronization controller both electrically connected to the dq converter, and the dq converter, PWM modulator, and voltage source converter connected in series.

[0011] This patent proposes a converter control method, device, and storage medium considering AC-side phase angle feedback. For scenarios involving DC-AC power converters connected to an infinite bus (IB) or dynamic center-inertia (COI) grid, it constructs a model incorporating energy dynamics, a DC link, an LC output filter, transmission lines, and a converter. Coordinate systems describe dynamic equations, such as (Energy Source Dynamics) (DC link dynamics), etc., involving key variables such as filter inductors, capacitors, and line parameters. Define state vectors. Establish closed-loop dynamic equations, such as Hybrid angle control (HAC) is achieved by combining DC voltage deviation with nonlinear angle feedback.

[0012] The two differ fundamentally in their technical solutions, implementation paths, physical structures, and gain effects. Summary of the Invention

[0013] To address the shortcomings of existing technologies, this invention develops a converter control method, device, and storage medium that considers AC side phase angle feedback. It aims to solve the stability problem of low-inertia power systems by using hybrid angle control to combine DC-based matching control with nonlinear angle feedback, thereby achieving stable operation of the power converter under different power grid models. Furthermore, it enables coordinated operation between converters without relying on communication when multiple converters are in parallel.

[0014] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0015] A converter control method considering AC side phase angle feedback is characterized by the following steps:

[0016] S1. For DC-AC power converters, considering their connection to an infinite bus or a dynamically centered inertial grid, establish a model that includes energy dynamics.

[0017] S2. Determine the closed-loop dynamic equations under the hybrid angle control strategy;

[0018] S3. Based on the model in step S1 and the control strategy in step S2, analyze the existence, stability and boundedness of the equilibrium point of the closed-loop system, and give the corresponding parameter conditions.

[0019] S4. Considering the safety constraints of the power converter, design a current limiting control that is compatible with hybrid angle control, and analyze its stability.

[0020] S5. Research the implementation method of hybrid angle control in practical applications, analyze its robustness and behavior under different working conditions, and verify it through numerical examples.

[0021] As a preferred technical solution of the present invention, step S1 is specifically as follows:

[0022] A three-phase two-level DC-AC converter is connected to an infinite bus. A first-order system is used to simulate a DC energy source to provide input to a controlled DC current source. An AC filter is modeled using LC elements, and the inductance line, which is considered as a low-to-medium voltage transformer model, is connected to the infinite bus.

[0023] As a preferred technical solution of the present invention: In step S1, considering the case where the DC-AC power converter is connected to an infinite bus or a dynamic center inertial grid, the following is established: The dynamic equation model in the frame is as follows:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] in, Energy time constant, To output direct current for energy, This is a reference value for DC current. For DC link capacitor, This is the DC bus voltage. For the equivalent conductance of the DC link, This is a reference range. It is the absolute phase angle of the converter. For filtering inductors, For the resistance associated with the component, This is the DC bus voltage. For the modulation vector in The values ​​of the coordinate system For the filter inductor current in Values ​​in the coordinate system; This is the voltage across the filter capacitor. For filtering capacitors, For electrical conductivity, For the filter inductor current in The values ​​of the coordinate system This is the voltage across the filter capacitor. For line inductance, The resistor is related to the line inductance. This is the voltage across the filter capacitor. For the line inductance current in The values ​​of the coordinate system For infinite busbars Voltage in the frame, It is the moment of inertia. It is the inertial constant. Based on power, Indicates mechanical torque. This represents the combined damping and sag coefficient. Indicates electrical torque. This indicates mechanical torque.

[0034] As a preferred technical solution of the present invention: In step S2, the closed-loop dynamic equation of the grid-type converter under the hybrid angle control strategy is established, as follows:

[0035]

[0036]

[0037]

[0038]

[0039] in The rated angular frequency, , To control the gain, For reference angle.

[0040] As a preferred technical solution of the present invention, step S3 is as follows:

[0041] Using matrix analysis, we determine the full-rank condition of the linear equation, prove the uniqueness of the solution, and determine that there is a unique equilibrium set in the closed-loop system. This equilibrium set contains two disjoint equilibrium points, and the equilibrium angle is related to the reference angle. We then prove the existence of the equilibrium points.

[0042] Define error coordinates Construct Lyapunov functions And the system stability parameters are derived. Under these conditions, prove the global asymptotic stability of the equilibrium point and the instability of the other equilibrium point;

[0043] Consider the system's disturbance term The closed-loop system equations are rewritten as follows: Using the Lyapunov-Krasovskii functional method, the system state is analyzed. Does it meet the requirements? We obtain the boundedness condition of the system, ensuring that the system is bounded under certain perturbations, thus proving the boundedness of the system.

[0044] As a preferred technical solution of the present invention, step S4 is specifically as follows:

[0045] The design incorporates current-limiting control compatible with hybrid angle control, as detailed below:

[0046] The dynamic analysis of the current amplitude is as follows:

[0047]

[0048]

[0049]

[0050] in, It is the phase of the modulation vector. It is the phase of the current vector. It is the phase of the voltage vector. It is the magnitude of the voltage vector.

[0051] The current limiting control design based on duty cycle adjustment is as follows:

[0052]

[0053]

[0054] in, This is the duty cycle adjustment amount. Minimum duty cycle, To adjust the parameters, For current threshold, This is the original reference range.

[0055] By incorporating current limiting control into the closed-loop system, the system stability is analyzed as follows:

[0056] Introducing current-limiting control into the aforementioned closed-loop dynamic equations, the reference amplitude changes accordingly based on the state vector. The system stability is then analyzed, including:

[0057] Define a new Lyapunov function Taking its derivative, we get Then through analysis The stability of a system is judged by the sign of its positive or negative sign. If the system satisfies the following condition near the equilibrium point... If the system is locally asymptotically stable at that equilibrium point, then by combining current limiting control, we can obtain the parameter conditions that guarantee the stability of the system.

[0058] As a preferred technical solution of the present invention, step S5 is as follows:

[0059] Alternative implementation methods based on DC and AC measurements are used to obtain the relative angle dependent on hybrid angle control by measuring DC voltage. IB voltage Derive the relative angle;

[0060] Under the assumption of time scale separation, an approximation method is used to achieve the hybrid angle control. Meanwhile, considering the uncertainty of line parameters, an estimation method is used to derive the actual implementation method of hybrid angle control.

[0061] Considering the impact of parameter uncertainties and measurement noise on the system, the perturbation system equations are established. Using robust control theory, we present the conditions for the boundedness of the disturbed system and the stability analysis of the equilibrium point.

[0062] The paper elucidates the grid formation behavior under hybrid angle control, achieving relative angle control by adjusting the modulation angle. It analyzes the differential slope of the active power-frequency relationship in a converter-dynamic center inertial system where frequency drop is permissible. The paper derives its expression and analyzes the power-frequency characteristics of the system at different equilibrium points, provides optimization suggestions, gives a consistent definition of the reference modulation amplitude, introduces a feedforward AC voltage and power control method based on steady-state DC voltage, AC voltage amplitude and power flow, analyzes its behavior under different operating conditions, and improves the control strategy of hybrid angle control.

[0063] A device, characterized in that it comprises:

[0064] One or more processors, a memory, a program stored in the memory and executable on the processor, and a data bus for enabling communication between the processor and the memory, wherein the program, when executed by the processor, implements a converter control method that takes into account AC side phase angle feedback.

[0065] A storage medium for computer-readable storage, characterized in that the storage medium stores one or more programs, which, when executed by one or more processors, implement the converter control method considering AC side phase angle feedback.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] This invention enables more precise analysis of the operating performance of converters that take into account AC phase angle feedback under various operating conditions, optimizes the configuration of control parameters, effectively improves system stability, robustness and dynamic performance, and provides strong support for the reliable operation of power systems. Attached Figure Description

[0068] Figure 1 is a flowchart illustrating a converter control method considering AC side phase angle feedback according to an embodiment of the present invention.

[0069] Figure 2 is a control loop structure diagram of a converter control method considering AC side phase angle feedback according to an embodiment of the present invention;

[0070] Figure 3 is a schematic diagram of the structure for implementing the hybrid angle control (HAC) strategy of a three-phase two-stage DC-AC converter according to an embodiment of the present invention;

[0071] Figure 4 is a schematic diagram of the node test system for synchronous motors and power converters according to an embodiment of the present invention;

[0072] Figure 5 shows a Möbius strip boundary from an embodiment of the present invention. arrive The angular space of the range;

[0073] Figure 6 shows the d-axis grid current of the converter considering AC side phase angle feedback in an embodiment of the present invention;

[0074] Figure 7 shows the d-axis filter current of the converter considering AC side phase angle feedback in an embodiment of the present invention;

[0075] Figure 8 shows the d-axis filter voltage of the converter considering AC side phase angle feedback in an embodiment of the present invention;

[0076] Figure 9 shows the q-axis grid current of the converter considering AC side phase angle feedback in an embodiment of the present invention;

[0077] Figure 10 shows the q-axis filter current of the converter considering AC side phase angle feedback in an embodiment of the present invention.

[0078] Figure 11 shows the q-axis filter voltage of the converter considering AC side phase angle feedback in an embodiment of the present invention.

[0079] Figure 12 shows the converter-related angle under the Hybrid Angle Control (HAC) strategy in an embodiment of the present invention.

[0080] A chart of degree characteristics;

[0081] Figure 13 is a graph showing the dynamic characteristics of DC voltage in the power system model of the Hybrid Angle Control (HAC) strategy according to an embodiment of the present invention.

[0082] Figure 14 This is a structural diagram of the device in this invention. Detailed Implementation

[0083] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0084] To address the shortcomings of existing technologies, this invention develops a converter control method that considers AC side phase angle feedback. This method aims to solve the stability problem of low-inertia power systems. By using hybrid angle control, it combines DC-based matching control with nonlinear angle feedback to achieve stable operation of the power converter under different power grid models. Furthermore, it enables coordinated operation between converters without relying on communication when multiple converters are operating in parallel. This has significant theoretical and practical implications for ensuring the safe and stable operation of the power grid.

[0085] As shown in Figure 1-13, the converter control method considering AC side phase angle feedback proposed in this invention includes the following steps:

[0086] S1. For DC-AC power converters, considering their connection to an infinite bus or dynamic center of inertia (COI) grid, establish a converter model that includes an explicit representation of energy dynamics, DC link, LC output filter, transmission line, etc.

[0087] S2. Determine the closed-loop dynamic equations under the hybrid angle control (HAC) strategy;

[0088] S3. Based on the model in step S1 and the control strategy in step S2, analyze the existence, stability and boundedness of the equilibrium point of the closed-loop system, and give the corresponding parameter conditions.

[0089] S4. Considering the safety constraints of the power converter, design a current limiting control compatible with hybrid angle control (HAC) and analyze its stability.

[0090] S5. Research the implementation method of hybrid angle control (HAC) in practical applications, analyze its robustness and behavior under different working conditions, and verify it through numerical examples.

[0091] This invention enables more precise analysis of the operating performance of converters that take into account AC phase angle feedback under various operating conditions, optimizes the configuration of control parameters, effectively improves system stability, robustness and dynamic performance, and provides strong support for the reliable operation of power systems.

[0092] The present invention specifically includes the following steps:

[0093] Step S1 is as follows:

[0094] A three-phase two-level DC-AC converter is connected to an infinite bus (IB). A first-order system is used to simulate a DC energy source to provide input to a controlled DC current source. An AC filter is modeled using LC elements, and an inductor line, which is considered as a low-to-medium voltage transformer model, is connected to the infinite bus (IB).

[0095] Considering the connection of the DC-AC power converter to an infinite bus (IB) or dynamic center of inertia (COI) grid, the following is established: The dynamic equation model in the frame is as follows:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] in, Energy time constant, To output direct current for energy, This is a reference value for DC current. For DC link capacitor, This is the DC bus voltage. For the equivalent conductance of the DC link, This is a reference range. It is the absolute phase angle of the converter. For filtering inductors, For the resistance associated with the component, This is the DC bus voltage. For the modulation vector in The values ​​of the coordinate system For the filter inductor current in Values ​​in the coordinate system; This is the voltage across the filter capacitor. For filtering capacitors, For electrical conductivity, For the filter inductor current in The values ​​of the coordinate system This is the voltage across the filter capacitor. For line inductance, The resistor is related to the line inductance. This is the voltage across the filter capacitor. For the line inductance current in The values ​​of the coordinate system For infinite busbars Voltage in the frame, It is the moment of inertia. It is the inertial constant. Based on power, Indicates mechanical torque. This represents the combined damping and sag coefficient. Indicates electrical torque. This indicates mechanical torque.

[0106] In step S2, after defining the relevant control expressions, the closed-loop dynamic equations of the grid-type converter under the Hybrid Angle Control (HAC) strategy are established, as follows:

[0107]

[0108]

[0109] (12)

[0110]

[0111] in The rated angular frequency, , To control the gain, For reference angle.

[0112] Step S3 is as follows:

[0113] Based on this model and control strategy, the existence, stability, and boundedness of the equilibrium point of the closed-loop system are analyzed, and the corresponding parameter conditions are given as follows:

[0114] Assuming the DC voltage satisfies the reference value under steady state. By setting the right side of the closed-loop system to zero, a series of equations are obtained. Using matrix analysis, the full-rank condition of the linear equations is judged, and it is determined that there exists a unique equilibrium set in the closed-loop system. This set contains two non-intersecting equilibrium points, and the equilibrium angle is related to the reference angle. The uniqueness of the solution of the relevant equations is proved.

[0115] Define error coordinates Construct Lyapunov functions And the system stability parameters are derived. Under these conditions, we prove the global asymptotic stability of the equilibrium point and the instability of the other equilibrium point.

[0116] Consider the system's disturbance term The closed-loop system equations are rewritten as follows: Using methods such as Lyapunov-Krasovskii functionals, the system state is analyzed. Does it meet the requirements? We obtain the boundedness condition of the system, ensuring that the system is bounded under certain perturbations, thus proving the boundedness of the system.

[0117] Step S4 is as follows:

[0118] Considering the safety constraints of the power converter, a current limiting control compatible with Hybrid Angle Control (HAC) is designed. While the HAC strategy improves converter performance, compatible current limiting control is needed to ensure stable system operation under abnormal conditions such as overcurrent, as follows:

[0119] The dynamic analysis of the current amplitude is as follows:

[0120]

[0121]

[0122]

[0123] in, It is the phase of the modulation vector. It is the phase of the current vector. It is the phase of the voltage vector. It is the magnitude of the voltage vector.

[0124] The current limiting control design based on duty cycle adjustment is as follows:

[0125]

[0126]

[0127] in, This is the duty cycle adjustment amount. Minimum duty cycle, To adjust the parameters, Current threshold

[0128] value, This is the original reference range.

[0129] Introducing current-limiting control into the aforementioned closed-loop dynamic equations, the reference amplitude changes accordingly based on the state vector. The system stability is then analyzed, including:

[0130] Define a new Lyapunov function Taking its derivative, we get Then through analysis The stability of a system is judged by the sign of its positive or negative value. If the system satisfies the following condition near the equilibrium point... If the system is locally asymptotically stable at that equilibrium point, then by combining current limiting control, we can obtain the parameter conditions that guarantee the stability of the system.

[0131] Step S5 is as follows:

[0132] This study investigates the implementation methods, robustness, and behavior of Hybrid Angle Control (HAC) in practical applications, and verifies these findings through numerical examples, as follows:

[0133] Alternative methods for obtaining HAC-dependent relative angles based on DC and AC measurements involve angle-related calculations and analyses, which raise issues of angle periodicity and multi-valuedness. In traditional circular topologies, the angle... The evolution space of angles is limited, but in the HAC system, certain characteristics of angles make the analysis more complex. Here, we introduce the concept of a Möbius strip boundary to extend the evolution space of angles to the Möbius strip boundary. In this special space, angular terms that were originally multivalued on a circle become analyzable by measuring DC voltage. IB voltage We derive the relative angle; under the assumption of time scale separation, we use an approximate method to achieve it, while considering the uncertainty of line parameters, we use estimation techniques to derive the actual implementation method of HAC.

[0134] Consider the impact of parameter uncertainties and measurement noise on the system. Establish the equations for the disturbed system. The evolution characteristics of the Möbius strip at its boundary can affect the stability assessment of the system. Due to the special topological structure of the Möbius strip boundary, when analyzing disturbance inputs... To output The transfer function The norm and the characteristics of the angle on the Möbius strip boundary when solving the Riccati equation can more accurately determine the controller gain matrix. Using robust control theory, we present the conditions for the boundedness of the disturbed system and the stability analysis of the equilibrium point.

[0135] This paper elucidates the grid formation behavior of HAC (High-Intensity Conversion) and demonstrates how relative angle control is achieved by adjusting the modulation angle. It analyzes the differential slope of the active power-frequency relationship in a converter-COI (Converter-on-Insulator) system that allows for frequency drop. The paper derives its expression and analyzes the power-frequency characteristics of the system at different equilibrium points. Optimization suggestions are given, a consistent definition of the reference modulation amplitude is introduced, and a feedforward AC voltage and power control method based on steady-state DC voltage, AC voltage amplitude, and power flow is presented. Its behavior under different operating conditions is analyzed, and the control strategy of HAC is improved.

[0136] The present invention proposes a device comprising:

[0137] One or more processors, a memory, a program stored in the memory and executable on the processor, and a data bus for enabling communication between the processor and the memory, wherein the program, when executed by the processor, implements a converter control method that takes into account AC side phase angle feedback.

[0138] A storage medium for computer-readable storage, the storage medium storing one or more programs, which, when executed by one or more processors, implement a converter control method taking into account AC side phase angle feedback.

[0139] like Figure 14 As shown, device 140 includes one or more processors 141 and memory 143.

[0140] The processor 141 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0141] Memory 143 may include one or more computer program products, which may include various forms of storage media, such as volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the storage medium, and processor 141 may execute the program instructions to implement the methods of the software programs in the various embodiments of the present invention described above, and / or other desired functions. In one example, the device may further include an input device 142 and an output device 144, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0142] In addition, the input device 142 may also include, for example, a keyboard, a mouse, etc.

[0143] The output device 144 can output various information to the outside. The output device may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0144] Of course, for the sake of simplicity, Figure 14 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0145] It should also be noted that in the methods, apparatus, and storage media of the present invention, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the present invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any modifications or equivalent variations made based on the technical essence of the present invention still fall within the scope of protection claimed by the present invention.

Claims

1. A converter control method considering AC side phase angle feedback, characterized in that, Includes the following steps: S1. For DC-AC power converters, considering their connection to an infinite bus or a dynamically centered inertial grid, establish a model that includes energy dynamics. In step S1, considering the case where the DC-AC power converter is connected to an infinite bus or a dynamically centered inertial grid, the following is established: The dynamic equation model in the frame is as follows: （1） （2） （3） （4） （5） （6） （7） （8） （9） in, The energy time constant, To output direct current for energy, This is a reference value for DC current. For DC link capacitor, This is the DC bus voltage. For the equivalent conductance of the DC link, This is a reference range. It is the absolute phase angle of the converter. For filtering inductors, For the resistance associated with the component, For the modulation vector in The values ​​of the coordinate system For the filter inductor current in Values ​​in the coordinate system; This is the voltage across the filter capacitor. For filtering capacitors, For electrical conductivity, For the filter inductor current in The values ​​of the coordinate system This is the voltage across the filter capacitor. For line inductance, The resistor is related to the line inductance. This is the voltage across the filter capacitor. For the line inductance current in The values ​​of the coordinate system For infinite busbars Voltage in the frame, It is the moment of inertia. It is the inertial constant. Based on power, Indicates mechanical torque. This represents the combined damping and sag coefficient. Indicates electrical torque. Indicates mechanical torque; S2. Determine the closed-loop dynamic equations under the hybrid angle control strategy; In step S2, the closed-loop dynamic equations of the grid-type converter under the hybrid angle control strategy are established, as follows: （10） （11） （12） （13） in The rated angular frequency, , To control the gain, For reference angle; S3. Based on the model in step S1 and the control strategy in step S2, analyze the existence, stability and boundedness of the equilibrium point of the closed-loop system, and give the corresponding parameter conditions. S4. Considering the safety constraints of the power converter, design a current limiting control that is compatible with hybrid angle control, and analyze its stability. S5. Research and design the implementation method of hybrid angle control in practical applications, analyze its robustness and its behavior under different working conditions, and verify it through numerical examples.

2. The converter control method considering AC side phase angle feedback according to claim 1, characterized in that, Step S1 is as follows: A three-phase two-level DC-AC converter is connected to an infinite bus. A first-order system is used to simulate a DC energy source to provide input to a controlled DC current source. An AC filter is modeled using LC elements, and the inductance line, which is considered as a low-to-medium voltage transformer model, is connected to the infinite bus.

3. The converter control method considering AC side phase angle feedback according to claim 1, characterized in that, Step S3 is as follows: Using matrix analysis, we determine the full-rank condition of the linear equation, prove the uniqueness of the solution, and determine that there is a unique equilibrium set in the closed-loop system. This equilibrium set contains two disjoint equilibrium points, and the equilibrium angle is related to the reference angle. We then prove the existence of the equilibrium points. Define error coordinates Construct Lyapunov functions And the system stability parameters are derived. Under these conditions, prove the global asymptotic stability of the equilibrium point and the instability of the other equilibrium point; Consider the system's disturbance term The closed-loop system equations are rewritten as follows: Using the Lyapunov-Krasovskii functional method, the system state is analyzed. Does it meet the requirements? We obtain the boundedness condition of the system, ensuring that the system is bounded under certain perturbations, thus proving the boundedness of the system.

4. The converter control method considering AC side phase angle feedback according to claim 1, characterized in that, Step S4 is as follows: The design incorporates current-limiting control compatible with hybrid angle control, as detailed below: The dynamic analysis of the current amplitude is as follows: （14） （15） （16） in, It is the phase of the current vector. It is the phase of the voltage vector. It is the magnitude of the voltage vector. The current limiting control design based on duty cycle adjustment is as follows: （17） （18） in, This is the duty cycle adjustment amount. Minimum duty cycle, To adjust the parameters, For current threshold, This is the original reference range. By incorporating current limiting control into the closed-loop system, the system stability is analyzed as follows: Introducing current-limiting control into the aforementioned closed-loop dynamic equations, the reference amplitude changes accordingly based on the state vector. The system stability is then analyzed, including: Define a new Lyapunov function Taking its derivative, we get Then through analysis The stability of a system is judged by the sign of its equilibrium state; if the equilibrium condition is satisfied near the equilibrium point... If the system is locally asymptotically stable at the equilibrium point, then by combining current limiting control, the parameter conditions that guarantee the stability of the system can be obtained.

5. The converter control method considering AC side phase angle feedback according to claim 1, characterized in that, Step S5 is as follows: Alternative implementation methods based on DC and AC measurements are used to obtain the relative angle dependent on hybrid angle control by measuring DC voltage. Infinite bus voltage Derive the relative angle; Under the assumption of time scale separation, an approximation method is used to achieve the hybrid angle control. Meanwhile, considering the uncertainty of line parameters, an estimation method is used to derive the actual implementation method of hybrid angle control. Considering the impact of parameter uncertainties and measurement noise on the system, the perturbation system equations are established. Using robust control theory, we present the conditions for the boundedness of the disturbed system and the stability analysis of the equilibrium point. The paper elucidates the grid formation behavior under hybrid angle control, achieving relative angle control by adjusting the modulation angle. It analyzes the differential slope of the active power-frequency relationship in a converter-dynamic center inertial system where frequency drop is permissible. The paper derives its expression and analyzes the power-frequency characteristics of the system at different equilibrium points, provides optimization suggestions, gives a consistent definition of the reference modulation amplitude, introduces a feedforward AC voltage and power control method based on steady-state DC voltage, AC voltage amplitude and power flow, analyzes its behavior under different operating conditions, and improves the control strategy of hybrid angle control.

6. A device, characterized in that, include: One or more processors, a memory, a program stored in the memory and executable on the processor, and a data bus for enabling communication between the processor and the memory, wherein the program, when executed by the processor, implements the converter control method considering AC side phase angle feedback as described in any one of claims 1-5.

7. A storage medium for computer-readable storage, characterized in that, The storage medium stores one or more programs, which, when executed by one or more processors, implement the converter control method considering AC side phase angle feedback as described in any one of claims 1-5.

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