Method for controlling direct-current voltage of static var generator and static var generator

Abstract

The embodiment of the invention provides a control method for direct-current voltage of a static var generator and the static var generator. The method comprises the following steps: acquiring a reference voltage of an input side of the static var generator, and determining a reference current according to the reference voltage and a first observation value and a second observation value of an expansion state observation module; wherein the first observation value represents an observation value of the expansion state observation module on the DC voltage, and the second observation value represents an observation value of the expansion state observation module on the total disturbance; obtaining the actual current of the output side of the static var generator, and generating a control signal according to the reference current and the actual current; wherein the control signal is used for controlling the conduction state of a switch in the static var generator so as to control the direct current voltage of the static var generator. The method is used for accurately and quickly controlling the direct-current voltage of the static var generator.

Description

[0001] This application claims the priority of a Chinese patent application titled "Control Method for DC Voltage of Static Var Generator and Static Var Generator" with the application number 202510319838.5, which was filed with the Chinese Patent Office on March 18, 2025. The entire content thereof is incorporated herein by reference. Technical Field

[0002] This application relates to the fields of power systems and reactive power generators, and particularly to a control method for the DC voltage of a static var generator and a static var generator. Background Art

[0003] With the construction of a new type of power grid system, more power equipment is connected to the grid system. At the same time, a higher proportion of new energy power generation equipment is also connected to the grid system. The output power of new energy power generation equipment varies greatly, resulting in voltage fluctuations in the grid system. Therefore, it is necessary for a static var generator to compensate reactive power into the grid system to stabilize the voltage amplitude of the grid system.

[0004] The reactive power compensation of a static var generator relies on controlling the DC voltage on its DC side. In some technologies, the DC voltage of a static var generator is controlled by traditional Proportional Integral Derivative (PID). In the above technologies, the PID control method cannot control the DC voltage quickly and accurately in the face of disturbances.

[0005] Therefore, there is an urgent need for a solution that can accurately and quickly control the DC voltage of a static var generator. Summary of the Invention

[0006] The control method for the DC voltage of a static var generator and the static var generator provided by the embodiments of this application are used to accurately and quickly control the DC voltage of a static var generator.

[0007] In a first aspect, the embodiments of this application provide a control method for the DC voltage of a static var generator, which is applied to a processor in the static var generator and includes:

[0008] Obtain the reference voltage on the input side of the static var generator, and determine the reference current according to the reference voltage, the first observation value and the second observation value of the extended state observer module; wherein, the first observation value represents the observation value of the DC voltage by the extended state observer module, and the second observation value represents the observation value of the total disturbance by the extended state observer module;

[0009] Obtain the actual current on the output side of the static var generator, and generate a control signal based on the reference current and the actual current; wherein, the control signal is used to control the conduction state of the switch in the static var generator to control the DC voltage of the static var generator.

[0010] In a possible implementation manner, determining the reference current according to the reference voltage, the first observation value and the second observation value of the extended state observer module includes:

[0011] Determine the tracking error according to the reference voltage, the first observation value of the extended state observer module, and a preset proportionality coefficient; wherein, the tracking error represents the error between the first observation value and the reference voltage;

[0012] Determine the reference current according to the tracking error, the second observation value of the extended state observer module, and the reciprocal of the preset approximate controller gain value.

[0013] In a possible implementation manner, the method further includes:

[0014] Determine the observation error at the current moment according to the DC voltage of the static var generator at the previous moment and the first observation value of the extended state observer module at the previous moment; wherein, the observation error represents the error between the first observation value and the DC voltage;

[0015] Determine the second observation value of the extended state observer module at the current moment according to the observation error at the current moment and a preset second gain value;

[0016] Determine the first observation value of the extended state observer module at the current moment according to the second observation value at the current moment, the observation error at the current moment, the first gain value, the reference current at the previous moment, and the preset approximate controller gain value.

[0017] In a possible implementation manner, the method further includes:

[0018] Determine the first gain value and the second gain value respectively according to the preset observation bandwidth of the extended state observer module according to a preset first rule; wherein, the first gain value represents the convergence speed of the first observation value of the extended state observer module towards the DC voltage; the second gain value represents the convergence speed of the second observation value of the extended state observer module towards the total disturbance; the first rule includes the numerical relationship between the observation bandwidth and the first gain value, and the numerical relationship between the observation bandwidth and the second gain value.

[0019] In a possible implementation, the extended state observer module has a characteristic equation and a preset standard equation; the poles of the characteristic equation represent the combined observation effects of the first gain value and the second gain value on the DC voltage and the total disturbance; the poles of the standard equation represent the observation bandwidth's observation effects on the DC voltage and the total disturbance; wherein, the observation effects represent the convergence speed of the first observed value to the DC voltage and the observation accuracy of the second observed value to the total disturbance.

[0020] According to the preset observation bandwidth of the extended state observer module, the first gain value and the second gain value are determined respectively, including:

[0021] According to the pole placement method, the poles of the characteristic equation are made equal to the poles of the standard equation, so as to determine the first gain value and the second gain value respectively.

[0022] In a possible implementation, generating a control signal according to a reference current and an actual current includes:

[0023] Determine the difference between the reference current and the actual current as the current deviation;

[0024] Determine a voltage control quantity according to the current deviation;

[0025] Generate a control signal according to the voltage control quantity; wherein, the control signal is a pulse width modulation PWM signal.

[0026] In a possible implementation, when the control signal controls the conduction state of the switches in the static var generator to control the DC voltage of the static var generator, it includes:

[0027] Control the conduction state of the switches of the inverter bridge in the static var generator through the control signal to control the actual current to track the reference current;

[0028] When the actual current tracks the reference current, control the charging or discharging of the capacitor on the input side of the static var generator to control the DC voltage of the static var generator.

[0029] In a second aspect, an embodiment of the present application provides a control device for the DC voltage of a static var generator, including:

[0030] A first processing module, configured to obtain a reference voltage on the input side of the static var generator, and determine a reference current according to the reference voltage, and the first observed value and the second observed value of the extended state observer module; wherein, the first observed value represents the observed value of the extended state observer module for the DC voltage, and the second observed value represents the observed value of the extended state observer module for the total disturbance;

[0031] A second processing module, configured to obtain the actual current on the output side of the static var generator, and generate a control signal according to a reference current and the actual current; wherein, the control signal is used to control the conduction state of a switch in the static var generator to control the DC voltage of the static var generator.

[0032] In a possible implementation manner, according to a reference voltage, and a first observation value and a second observation value of an extended state observer module, a reference current is determined. The first processing module is configured to:

[0033] Determine a tracking error according to the reference voltage, the first observation value of the extended state observer module, and a preset proportionality coefficient; wherein, the tracking error represents the error between the first observation value and the reference voltage;

[0034] Determine the reference current according to the tracking error, the second observation value of the extended state observer module, and the reciprocal of a preset approximate controller gain value.

[0035] In a possible implementation manner, the first processing module is further configured to:

[0036] Determine an observation error at the current moment according to the DC voltage of the static var generator at the previous moment and the first observation value of the extended state observer module at the previous moment; wherein, the observation error represents the error between the first observation value and the DC voltage;

[0037] Determine the second observation value of the extended state observer module at the current moment according to the observation error at the current moment and a preset second gain value;

[0038] Determine the first observation value of the extended state observer module at the current moment according to the second observation value at the current moment, the observation error at the current moment, a first gain value, the reference current at the previous moment, and a preset approximate controller gain value.

[0039] In a possible implementation manner, the first processing module is further configured to:

[0040] Determine the first gain value and the second gain value respectively according to a preset observation bandwidth of the extended state observer module according to a preset first rule; wherein, the first gain value represents the convergence speed of the first observation value of the extended state observer module towards the DC voltage; the second gain value represents the convergence speed of the second observation value of the extended state observer module towards the total disturbance; the first rule includes the numerical relationship between the observation bandwidth and the first gain value, and the numerical relationship between the observation bandwidth and the second gain value.

[0041] In a possible implementation, the extended state observer module has a characteristic equation and a preset standard equation; the poles of the characteristic equation characterize the combined observation effects of the first gain value and the second gain value on the DC voltage and the total disturbance; the poles of the standard equation characterize the observation effects of the observation bandwidth on the DC voltage and the total disturbance; wherein, the observation effects characterize the convergence rate of the first observation value to the DC voltage and the observation accuracy of the second observation value to the total disturbance.

[0042] According to the preset observation bandwidth of the extended state observer module, the first gain value and the second gain value are respectively determined. The first processing module is used for:

[0043] According to the pole placement method, make the poles of the characteristic equation equal to the poles of the standard equation, so as to respectively determine the first gain value and the second gain value.

[0044] In a possible implementation, a control signal is generated according to the reference current and the actual current. The second processing module is used for:

[0045] Determine the difference between the reference current and the actual current as the current deviation.

[0046] Determine the voltage control amount according to the current deviation.

[0047] Generate a control signal according to the voltage control amount; wherein, the control signal is a pulse width modulation (PWM) signal.

[0048] In a possible implementation, when the control signal controls the conduction state of the switches in the static var generator to control the DC voltage of the static var generator, the second processing module is used for:

[0049] Control the conduction state of the switches of the inverter bridge in the static var generator through the control signal to control the actual current to track the reference current.

[0050] When the actual current tracks the reference current, control the charging or discharging of the capacitor on the input side of the static var generator to control the DC voltage of the static var generator.

[0051] In a third aspect, an embodiment of the present application provides a static var generator, including: a memory, a processor;

[0052] The memory stores computer-executable instructions.

[0053] The processor executes the computer-executable instructions stored in the memory, so that the processor executes the above first aspect and / or various possible implementation manners of the first aspect.

[0054] Fourthly, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the above first aspect and / or various possible implementation manners of the first aspect.

[0055] Fifthly, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the above first aspect and / or various possible implementation manners of the first aspect.

[0056] The method for controlling the DC voltage of the static var generator and the static var generator provided by the embodiments of the present application determine a reference current by obtaining a target reference voltage and based on the reference voltage, the observed value of the DC voltage by a pre-constructed extended state observer module, and the observed value of the total disturbance; obtain an actual current, and generate a control signal based on the reference current and the actual current; control the conduction state of the switches of the inverter bridge in the static var generator through the control signal, thereby realizing the control of the DC voltage. It can realize fast and accurate control of the DC voltage of the static var generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application.

[0058] Figure 1 is a schematic structural diagram of a static var generator;

[0059] Figure 2 is a schematic flowchart of the method for controlling the DC voltage of the static var generator provided by the present application Figure 1 ;

[0060] Figure 3 is a schematic flowchart of the method for controlling the DC voltage of the static var generator provided by the present application Figure 2 ;

[0061] Figure 4 is a schematic diagram of the control logic of an exemplary active disturbance rejection controller;

[0062] Figure 5 is a schematic flowchart of the method for controlling the DC voltage of the static var generator provided by the present application Figure 3 ;

[0063] Figure 6 is a schematic diagram of experimental results;

[0064] Figure 7 is a schematic structural diagram of the device for controlling the DC voltage of the static var generator provided by the present application;

[0065] Figure 8 The structural schematic diagram of the static var generator provided for this application.

[0066] Through the above-mentioned drawings, specific embodiments of this application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of this application in any way, but to illustrate the concept of this application to those skilled in the art by referring to specific embodiments. Specific Embodiments

[0067] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description involves the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. On the contrary, they are merely examples of devices and methods consistent with some aspects of this application as detailed in the appended claims.

[0068] First, the terms related to this application are explained:

[0069] Static Var Generator (abbreviated as SVG): It refers to a device for compensating reactive power in a power system. It generates reactive current synchronized with the power system through an inverter bridge to achieve dynamic compensation of reactive power. Its main functions include: being able to dynamically compensate reactive power and maintain the voltage stability of the power system; filtering harmonics in the power grid, etc.

[0070] Extended State Observer (abbreviated as ESO): It can also be called an extended state observer. When controlling the static var generator, it is used to observe and estimate the state variables of the controlled system in real time, and observe and estimate the possible unknown disturbances of the controlled system. Based on the observed and estimated values of the state variables and the observed and estimated values of the unknown disturbances, compensation control is performed on the state variables of the controlled system.

[0071] Figure 1 It is the structural schematic diagram of the static var generator, as Figure 1 shown, the static var generator mainly consists of a DC-side capacitor, an inverter bridge, and an inductive filter. In Figure 1 , represents the capacitor of the DC-side capacitor; represents the DC voltage, that is, the voltage across the DC-side capacitor; represents the current flowing from the DC side to the inverter bridge; , , respectively represent the three-phase voltages on the output side of the static var generator; , , respectively represent the three-phase currents on the output side of the static var generator; represents the inductance of the inductive filter; represents the grid voltage.

[0072] With the accelerating construction speed of the new power grid system, more types of power equipment are connected to the grid system. Among them, the power equipment includes a higher proportion of new energy power generation equipment. The output power of these new energy power generation equipment varies greatly, resulting in voltage fluctuations in the grid system. Therefore, it is necessary to connect a static var generator to the grid system to compensate for reactive power, thereby stabilizing the voltage amplitude of the grid system.

[0073] Furthermore, the reactive power compensation of the static var generator relies on controlling the voltage across the DC-side capacitor of the static var generator, that is, controlling the DC voltage for control. The required reactive power is output through the energy storage of the DC-side capacitor to achieve reactive power compensation.

[0074] In some embodiments, the DC voltage of the static var generator is controlled by the traditional proportional-integral-derivative (PID) method.

[0075] In the above embodiments, it is necessary to accurately design the parameters of the PID controller. If the parameter design of the PID controller is too aggressive, the DC voltage will overshoot when facing a step disturbance, that is, the DC voltage exceeds the set target value; if the parameter design of the PID controller is too conservative, the control adjustment time of the DC voltage will be too long when facing a step disturbance. Therefore, when the DC voltage is controlled by the above PID control method, it is impossible to quickly and accurately control the DC voltage.

[0076] The control method for the DC voltage of the static var generator provided in this application determines the reference current by obtaining the target reference voltage and based on the observed value of the DC voltage and the observed value of the total disturbance from the pre-constructed extended state observer module; obtains the actual current, and generates a control signal based on the reference current and the actual current; controls the conduction state of the switches of the inverter bridge in the static var generator through this control signal, thereby realizing the control of the DC voltage. It can quickly and accurately control the DC voltage of the static var generator.

[0077] The following uses specific embodiments to elaborate in detail on the technical solution of the present application and how the technical solution of the present application solves the above technical problems. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0078] Figure 2 Flow schematic of the control method for the DC voltage of the static var generator provided by the present application Figure 1 , as Figure 2 shown, this method is applied to the processor of the static var generator and includes:

[0079] Step 201. Obtain the reference voltage on the input side of the static var generator, and determine the reference current according to the reference voltage, as well as the first observation value and the second observation value of the extended state observer module.

[0080] Among them, the first observation value represents the observation value of the DC voltage by the extended state observer module, and the second observation value represents the observation value of the total disturbance by the extended state observer module.

[0081] The control of the static var generator can adopt a double closed-loop control strategy. In the double closed-loop control strategy, it includes a voltage control outer loop and a current control inner loop. The voltage control outer loop determines the reference current according to the reference voltage and the actual voltage; the current control inner loop generates a control signal according to the reference current and the actual current.

[0082] Among them, in the control process of the voltage control outer loop, the control process of the voltage control outer loop can be realized by a linear active disturbance rejection controller.

[0083] In one example, the linear active disturbance rejection controller is composed of an extended state observer module, a linear error feedback law, and a disturbance estimation compensation. Among them, the extended state observer module can be used to observe the DC voltage to obtain the first observation value, denoted as ; it can also be used to observe the total disturbance of the system to obtain the second observation value, denoted as . Among them, the total disturbance of the system can include uncertainties brought by factors such as model error and reactive power change, as well as unknown controller gains.

[0084] Exemplarily, obtain the reference voltage on the input side of the static var generator. This reference voltage indicates the target value that the DC voltage of the static var generator needs to reach, denoted as .

[0085] By means of the voltage sensor provided on the DC-side capacitor, the actual voltage on the input side of the static var generator, i.e., the DC voltage, can be acquired. The DC voltage is predicted by the extended state observer module to obtain a first observed value; and the total disturbance is estimated by the extended state observer module to obtain a second observed value.

[0086] Based on the first observed value, the second observed value, and the reference voltage, the value of the reference current can be determined. Specifically, based on the first observed value and the value of the reference voltage, the tracking situation of the current auto-disturbance rejection controller for the reference voltage is determined. Based on the tracking situation of the reference voltage, and then taking into account the estimated value of the total disturbance, the value of the reference current at the next moment can be determined. At the next moment, it is necessary to control the actual current value on the output side of the static var generator to track the reference current value at the next moment. By tracking the reference current value at the next moment, the DC voltage on the input side of the static var generator is controlled to track the reference voltage.

[0087] Step 202. Obtain the actual current on the output side of the static var generator, and generate a control signal according to the reference current and the actual current.

[0088] Among them, the control signal is used to control the conduction state of the switches in the static var generator to control the DC voltage of the static var generator.

[0089] Exemplarily, obtain the actual current on the output side of the static var generator. Specifically, the actual current is acquired by means of the current sensor provided on the output side of the static var generator. According to the reference current determined in step 201 and the actual current, the control signal can be determined.

[0090] Combined Figure 1 Explanation, as Figure 1 shown, in the static var generator, an inverter bridge is included, and switch elements are included in the inverter bridge. The inverter bridge includes three groups of switches, and each group of switches includes two switch elements. Taking Figure 1 the leftmost first group of switches as an example, at the middle node of the two switches in the first group of switches, it is connected to the A-phase line of the power grid. Correspondingly, the middle node of the two switches in the second group of switches is connected to the B-phase line of the power grid, and the middle node of the two switches in the third group of switches is connected to the C-phase line of the power grid.

[0091] These switches in the inverter bridge can change their conduction states in response to the above control signal. Based on the switches with changed conduction states, the DC voltage of the DC-side capacitor on the input side of the static var generator can be changed, thereby realizing the change of the DC voltage.

[0092] Optionally, these switches in the inverter bridge can be any one or more combinations of the following: Insulated Gate Bipolar Transistor (IGBT for short), Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET for short), Gate Turn-Off Thyristor (GTO for short), Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistor (SiC MOSFET for short), Gallium Nitride High Electron Mobility Transistor (GaN HEMT for short).

[0093] The method for controlling the DC voltage of the static var generator provided by the embodiment of the present application determines a reference current by obtaining a target reference voltage and based on the reference voltage, the observed value of the DC voltage by a pre-constructed extended state observer module, and the observed value of the total disturbance; obtains the actual current, and generates a control signal based on the reference current and the actual current; controls the conduction state of the switches in the inverter bridge of the static var generator through this control signal, thereby realizing the control of the DC voltage. It can quickly and accurately control the DC voltage of the static var generator.

[0094] Figure 3 It is a schematic flow chart of the method for controlling the DC voltage of the static var generator provided by the present application Figure 2 , as Figure 3 shown, on the basis of the Figure 2 embodiment, step 201 is described in detail. When determining the reference current, the method includes:

[0095] Step 301. Determine a tracking error according to the reference voltage, the first observed value of the extended state observer module, and a preset proportional coefficient.

[0096] Among them, the tracking error characterizes the error between the first observed value and the reference voltage.

[0097] Exemplarily, the first observed value is the observed value of the DC voltage by the extended state observer module. During the control process of the active disturbance rejection controller, it is necessary to control the DC voltage to track the reference voltage. The first observed value can characterize the observed value of the current DC voltage. Through the reference voltage and the first observed value, the tracking error of the current active disturbance rejection controller can be determined.

[0098] Optionally, a preset proportionality coefficient can also be introduced during the tracking error calculation. This proportionality coefficient can characterize the response intensity of the tracking error, denoted as . For example, the larger this proportionality coefficient is, the higher the response sensitivity of the active disturbance rejection controller to the tracking error, and the faster the DC voltage will be controlled to change; on the contrary, the smaller this proportionality coefficient is, the lower the response sensitivity of the active disturbance rejection controller to the tracking error, and the slower the DC voltage will be controlled to change.

[0099] Step 302. Determine the reference current according to the tracking error, the second observation value of the extended state observer module, and the reciprocal of the preset approximate controller gain value.

[0100] Exemplarily, the second observation value is the observation value of the extended state observer module for the total disturbance. During the control process of the active disturbance rejection controller, considering the influence of the total disturbance on the active disturbance rejection controller, it is necessary to eliminate the control influence of the total disturbance on the active disturbance rejection controller.

[0101] Optionally, a preset approximate controller gain value can also be introduced during the tracking error calculation, denoted as .

[0102] In one example, the reference current can be determined by the following formula (1):

[0103] (1)

[0104] In formula (1), represents the reference current; represents the preset approximate controller gain value; represents the preset proportionality coefficient; represents the reference current; represents the first observation value; represents the second observation value. It can be understood that represents the tracking error.

[0105] It should be noted that the calculation process of the above formula (1) can be understood as the disturbance estimation compensation and linear error feedback process of the active disturbance rejection controller. That is, the extended state observer module in the active disturbance rejection controller estimates the total disturbance and observes the DC voltage; according to the estimated value of the total disturbance (the second observation value), the observed value of the DC voltage (the first observation value), and the reference voltage, the current tracking situation of the active disturbance rejection controller is determined, and the reference current value is determined through error feedback.

[0106] In the above embodiments, according to the reference voltage and the first observation value, the tracking error in the control process of the active disturbance rejection controller is determined, and then combined with the second observation value of the total disturbance, the reference current is determined. It can quickly and accurately determine the reference current according to the reference voltage and the observation of the extended state observation module, laying a foundation for subsequent controlling the switches of the static var generator based on the reference current and the actual current.

[0107] Combined with the foregoing embodiments, it can be seen that in the active disturbance rejection controller, the extended state observation module is required to observe the DC voltage and the total disturbance to obtain the first observation value and the second observation value. This process is real-time. Therefore, on the basis of the foregoing embodiments, this embodiment explains how the extended state observation module specifically determines the first observation value and the second observation value.

[0108] Figure 4 For the control logic schematic diagram of an exemplary active disturbance rejection controller, as Figure 4 shown, in the control logic of the active disturbance rejection controller, an extended state observation module is included.

[0109] In one example, the formulaic expression of the extended state observation module is shown in formula (2):

[0110] (2)

[0111] In formula (2), represents the observation error, which characterizes the error value between the first observation value and the DC voltage; represents the first observation value; represents the DC voltage. represents the first-order differential of the first observation value, which characterizes the change rate of the first observation value on the time scale; represents the second observation value; represents the first gain value; represents the preset approximate controller gain value; represents the reference current. represents the first-order differential of the second observation value, which characterizes the change rate of the second observation value on the time scale; represents the second gain value.

[0112] Combined with Figure 4 the specific working process of the extended state observation module is explained.

[0113] According to the DC voltage of the static var generator at the previous moment and the first observation value of the extended state observation module at the previous moment, the observation error at the current moment is determined. Among them, the observation error characterizes the error between the first observation value and the DC voltage.

[0114] Exemplarily, obtain the DC voltage on the input side of the static var generator at the previous moment, and the first observation value of the extended state observer module at the previous moment, subtract the two to obtain the observation error at the current moment, that is, the observation error in the first expression among the three simultaneous expressions in formula (2). .

[0115] Determine the second observation value of the extended state observer module at the current moment according to the observation error at the current moment and the preset second gain value.

[0116] Exemplarily, after determining the observation error at the current moment , multiply it by the preset second gain value to obtain the rate of change of the second observation value with respect to time, that is, the first derivative of the second observation value in the third expression among the three simultaneous expressions in formula (2). .

[0117] Combined Figure 4 explanation, when the observation error is multiplied by the preset second gain value , it passes through the integration module. The integration module is as shown in Figure 4 " ". After passing through the integration module, integrate the first derivative of the second observation value to obtain the second observation value at the current moment .

[0118] Determine the first observation value of the extended state observer module at the current moment according to the second observation value at the current moment, the observation error at the current moment, the first gain value, the reference current at the previous moment, and the preset approximate controller gain value.

[0119] Exemplarily, obtain the reference current value at the previous moment, multiply it by the preset approximate controller gain value to obtain the first value at the current moment; obtain the determined observation error at the current moment, multiply it by the preset first gain value to obtain the second value at the current moment; add the second observation value at the current moment, the first value, and the second value to obtain the rate of change of the first observation value with respect to time, that is, the first derivative of the first observation value in the second expression among the three simultaneous expressions in formula (2). .

[0120] Combined Figure 4 explanation, after adding the second observation value at the current moment, the first value, and the second value to obtain the rate of change of the first observation value with respect to time, it passes through the integration module. Integrate the first derivative of the first observation value to obtain the first observation value at the current moment .

[0121] In the above example, the extended state observer module can continuously and real-time determine the first observation value and the second observation value at the current moment according to the reference current at the previous moment and the actual DC voltage. It can realize the real-time observation of the DC voltage and estimate the total disturbance of the active disturbance rejection controller. By feeding back the obtained first observation value and the second observation value, a new reference current at the current moment can be obtained, which lays a foundation for subsequent control of the DC voltage based on the new reference current.

[0122] Based on the foregoing example, the preset first gain value and second gain value can be determined according to the pole placement method.

[0123] In one example, according to the preset observation bandwidth of the extended state observer module, the first gain value and the second gain value are respectively determined according to a preset first rule.

[0124] Among them, the first gain value characterizes the convergence speed of the first observation value of the extended state observer module to the DC voltage; the second gain value characterizes the convergence speed of the second observation value of the extended state observer module to the total disturbance; the first rule includes the numerical relationship between the observation bandwidth and the first gain value, and the numerical relationship between the observation bandwidth and the second gain value.

[0125] Exemplarily, the first gain value and the second gain value can be preset fixed values, or can be determined by using the observation bandwidth of the extended state observer module according to the preset first rule. In the first rule, the numerical relationships between the observation bandwidth and the first gain value and the second gain value are respectively included.

[0126] For example, the first rule can be expressed by the following formula (3):

[0127] (3)

[0128] In formula (3), represents the preset observation bandwidth of the extended state observer module; represents the first gain value; represents the second gain value.

[0129] Combined with the foregoing example, it can be seen that when determining the first-order differential of the second observation value, it is obtained by multiplying the second gain value by the observation error. It can be understood that the larger the value of the second gain value, the larger the first-order differential of the second observation value, and the greater the change rate of the second observation value with respect to time. That is, the faster the convergence speed of the second observation value to the total disturbance.

[0130] Similarly, when determining the first-order differential of the first observation value, it is obtained by adding the first value, the second value, and the second observation value. When determining the second value, it is obtained by multiplying the first gain value by the observation error. It can be understood that the larger the value of the first gain value, the larger the value of the second value, which will make the first-order differential of the first observation value larger, and the change rate of the first observation value with respect to time is larger. That is, the convergence speed of the first observation value to the DC voltage is faster.

[0131] In the above example, using the observation bandwidth of the extended state observation module to represent the first gain value and the second gain value can represent the first gain value and the second gain value with the same parameter, which is convenient for adjusting the values of the first gain value and the second gain value. That is, only by adjusting the observation bandwidth of the extended state observation module, the adjustment of both the first gain value and the second gain value can be achieved simultaneously. It can improve the efficiency in the process of parameter adjustment.

[0132] Based on the above example, further introduce how to determine the first gain value and the second gain value based on the first rule.

[0133] In one example, the extended state observation module has a characteristic equation and a preset standard equation; the poles of the characteristic equation represent the combined observation influence of the first gain value and the second gain value on the DC voltage and the total disturbance; the poles of the standard equation represent the observation influence of the observation bandwidth on the DC voltage and the total disturbance. Among them, the observation influence represents the convergence speed of the first observation value to the DC voltage and the observation accuracy of the second observation value to the total disturbance.

[0134] Exemplarily, the characteristic equation of the extended state observation module can be represented by the following formula (4):

[0135] (4)

[0136] In formula (4), represents the complex variable of the Laplace transform; represents the first gain value; represents the second gain value.

[0137] Solving the characteristic equation shown in the above formula (4) can obtain the poles of the characteristic equation. The poles of the characteristic equation can be represented by the following formula (5):

[0138] (5)

[0139] In formula (5), represent two poles of the characteristic equation. The poles of the characteristic equation can characterize the combined observed influence of the first gain value and the second gain value on the DC voltage and the total disturbance. Specifically, the specific observed influence may include: the convergence rate of the first observed value to the DC voltage, and the observation accuracy of the second observed value to the total disturbance.

[0140] The standard equation preset by the extended state observation module can be expressed by the following formula (6):

[0141] (6)

[0142] In formula (6), represents the complex variable of the Laplace transform; represents the observation bandwidth preset by the extended state observation module.

[0143] Solving the standard equation shown in the above formula (6) can obtain the poles of the standard equation. The poles of the standard equation can be expressed by the following formula (7):

[0144] (7)

[0145] In formula (7), represent two poles of the standard equation. The poles of the standard equation can characterize the observed influence of the observation bandwidth on the DC voltage and the total disturbance. Specifically, the specific observed influence may include: the convergence rate of the first observed value to the DC voltage, and the observation accuracy of the second observed value to the total disturbance.

[0146] After determining the poles of the characteristic equation and the poles of the standard equation, the first gain value and the second gain value can be determined by the pole placement method.

[0147] Specifically, according to the pole placement method, make the poles of the characteristic equation equal to the poles of the standard equation, so as to determine the first gain value and the second gain value respectively.

[0148] Exemplarily, let and be equal, then the first gain value and the second gain value can be determined according to the expressions of formula (6) and formula (7) according to the one-to-one correspondence relationship, that is, the numerical relationship between the first gain value and the observation bandwidth shown in formula (3), and the numerical relationship between the second gain value and the observation bandwidth.

[0149] In the above example, through the poles of the characteristic equation and the poles of the standard equation of the extended observation unit, according to the pole placement method, the numerical relationships between the first gain value and the second gain value and the observation bandwidth can be determined respectively. It can be realized to determine the first gain value and the second gain value by the observation bandwidth.

[0150] In the above embodiments, the expansion observation unit can be used to observe the DC voltage in real time and accurately to obtain the first observation value, and estimate the total disturbance to obtain the second observation value; and the first observation value and the second observation value are used to determine a new reference current value in real time, and the DC voltage is controlled to follow the reference voltage value with the new reference current value.

[0151] Based on the foregoing embodiments, after the reference current is determined in the outer voltage control loop, a control signal is generated through the inner current control loop, thereby controlling the DC voltage. On the basis of any of the foregoing embodiments, this embodiment explains how the inner current control loop generates a control signal and how to control the DC voltage based on the control signal.

[0152] Figure 5 It is a schematic flow chart of the control method for the DC voltage of the static var generator provided by the present application Figure 3 , as Figure 5 shown, the generation of the control signal can be achieved through the following steps:

[0153] Step 501. Determine the difference between the reference current and the actual current as the current deviation.

[0154] Exemplarily, obtain the actual current on the output side of the static var generator, and subtract the actual current from the reference current to obtain the current deviation, denoted as .

[0155] Step 502. Determine the voltage control amount according to the current deviation.

[0156] Exemplarily, the voltage control amount can be determined by the following formula (8):

[0157] (8)

[0158] In formula (8), represents the voltage control amount; represents the proportional coefficient of the inner current control loop; represents the current deviation; represents the integral coefficient of the inner current control loop.

[0159] Step 503. Generate a control signal according to the voltage control amount.

[0160] Among them, the control signal is a pulse width modulation PWM signal.

[0161] Exemplarily, the voltage control amount is transformed through coordinate transformation to obtain a three-phase modulation signal; through this three-phase modulation signal, it is converted into a control signal using pulse width modulation (PWM) technology, and the control signal is a three-phase PWM signal.

[0162] It can be understood that the control signals of each phase respectively correspond to controlling the on - off states of a group of switches. Exemplarily, when the PWM signal of phase A outputs a high level, the switch of phase A is in the on state; if the PWM signal of phase A outputs a low level, the switch of phase A is in the off state.

[0163] In the above example, based on the current deviation between the reference current and the actual current, the voltage control amount of the control signal is determined, and coordinate transformation is performed based on the voltage control amount, so as to obtain the PWM control signal of each phase. Based on the PWM control signal of each phase, the on - off states of the switches of each phase of the inverter bridge in the static var generator can be controlled. It can realize the control of the switches in the static var generator based on the determined reference current, laying a foundation for subsequent controlling the DC voltage based on the on - off states of the switches.

[0164] In one example, when the control signal controls the on - off states of the switches in the static var generator to control the DC voltage of the static var generator, the method specifically includes:

[0165] Controlling the on - off states of the switches of the inverter bridge in the static var generator through the control signal to control the actual current to track the reference current.

[0166] When the actual current tracks the reference current, control the charging or discharging of the capacitor on the input side of the static var generator to control the DC voltage of the static var generator.

[0167] Exemplarily, combined with Figure 1 explain the above process. Control the on - off states of the switches of each phase in the inverter bridge of the static var generator through three - phase PWM signals. Based on the change of the on - off state, the actual current value on the output side of the inverter bridge changes, and the actual current value tracks the value represented by the reference current.

[0168] Specifically, when the voltage control amount increases, the duty cycle of the PWM signal increases, and the on - time of the switch becomes longer, so that the actual current increases; on the contrary, when the voltage control amount decreases, the duty cycle of the PWM signal decreases, and the on - time of the switch becomes shorter, so that the actual current decreases.

[0169] Furthermore, according to the change of the actual current, make the actual current track the reference current.

[0170] When the actual current tracks the reference current, the current on the input side of the static var generator will also change. For the DC - side capacitor, the DC - side capacitor is charged or discharged through the current on the input side of the static var generator When the DC - side capacitor is charged and discharged, the DC voltage across the DC - side capacitor will change, thus realizing the control of the DC voltage.

[0171] Specifically, according to the relationship among current, capacitance, and voltage change rate, the change rate of the voltage across the DC-side capacitor can be determined, that is, the change rate of the DC voltage. Based on the change rate of the DC voltage, the voltage across the DC-side capacitor is controlled, thereby realizing the control of the DC voltage.

[0172] Specifically, continue to combine Figure 1 to further explain the above process. According to Figure 1 The input and output terminals of the static var generator shown can obtain the mathematical model of the static var generator as shown in formula (9):

[0173] (9)

[0174] In formula (9), represents the inductance of the inductive filter; , , respectively represent the three-phase voltages on the output side of the static var generator; , , respectively represent the three-phase voltages of the power grid; represents the capacitance of the DC-side capacitor; represents the DC voltage, that is, the voltage across the DC-side capacitor; represents the current flowing from the DC side to the inverter bridge.

[0175] When the actual current tracks the reference current, the current flowing from the DC side to the inverter bridge will change; and according to the fourth expression in formula (9), when the current flowing from the DC side to the inverter bridge changes, the DC voltage will also change, thereby making the DC voltage follow the reference voltage .

[0176] In the above example, when the actual current follows the reference current, the charging and discharging energy of the DC-side capacitor can be controlled, and based on the charging and discharging energy of the DC-side capacitor, the control of the DC voltage can be realized.

[0177] In one example, to determine how to determine the state equation corresponding to the active disturbance rejection controller, the method may further include the following steps.

[0178] Perform a coordinate transformation on the above formula (9) to obtain the mathematical model of the static var generator in the two-phase synchronous stationary coordinate system, as shown in formula (10):

[0179] (10)

[0180] In formula (10), represents the d-axis component of the three-phase voltage on the output side of the static var generator, corresponding to the DC voltage in the foregoing embodiment; represents the q-axis component of the three-phase voltage on the output side of the static var generator; represents the d-axis component of the three-phase current on the output side of the static var generator; represents the q-axis component of the three-phase current on the output side of the static var generator, corresponding to the actual current in the foregoing embodiment; represents the d-axis component of the three-phase voltage of the power grid; represents the q-axis component of the three-phase voltage of the power grid.

[0181] Specifically, performing a coordinate transformation on the above formula (9) to obtain the mathematical model of the static var generator in the two-phase synchronous static coordinate system may include:

[0182] The above formula (9) is the mathematical model of the static var generator in the three-phase static coordinate system (a-b-c). Performing a Clarke transformation on the mathematical model in the three-phase static coordinate system to convert it into a two-phase static coordinate system (α-β); performing a Park transformation on the mathematical model in the two-phase static coordinate system to convert it into a two-phase rotating coordinate system (d-q).

[0183] According to the instantaneous reactive power theory, the output-side power of the inverter bridge of the static var generator can be determined, as shown in formula (11):

[0184] (11)

[0185] In formula (11), represents the output-side power of the inverter bridge of the static var generator.

[0186] Furthermore, ignoring the power losses of the switching devices and the lines in the inverter bridge, the power on the input side of the inverter bridge can be approximately equal to the power on the output side of the inverter bridge. The power on the input side of the inverter bridge can be calculated through the voltage and current on the DC side of the static var generator, as shown in formula (12):

[0187] (12)

[0188] In formula (12), represents the DC voltage, that is, the voltage across the DC-side capacitor; represents the current flowing out from the DC side to the inverter bridge.

[0189] Combining with the fourth expression in formula (9), formula (12) can be transformed to obtain the relationship between the DC voltage and the d-axis component of the three-phase current on the output side of the static var generator, as shown in formula (13):

[0190] (13)

[0191] Combining with the foregoing embodiments and formula (13), it can be known that when the actual current can track the reference current, formula (13) is rewritten to obtain formula (14):

[0192] (14)

[0193] In formula (14), represents the reference current; represents the given value of the reactive current.

[0194] Combining with formula (14), the state equation of the active disturbance rejection controller is designed as shown in formula (15):

[0195] (15)

[0196] In formula (15), represents the first-order differential of the DC voltage; represents the uncertain quantity from internal and external disturbances such as model error and reactive power change; represents the unknown controller gain; represents the preset approximate controller gain; represents the output of the active disturbance rejection controller; represents the DC voltage.

[0197] It should be noted that in formula (15), the first expression characterizes the change of the DC voltage with time, and the second expression characterizes that after integrating the first-order differential of the DC voltage, the output of the active disturbance rejection controller can be obtained as the DC voltage .

[0198] In addition, it should be noted that in formula (15), and can be denoted as the total disturbance g, corresponding to the total disturbance in the foregoing embodiments. It can be understood that the second observed value in the active disturbance rejection controller is the estimated value of the above total disturbance g.

[0199] Combining with the foregoing embodiments, it can be known that the reference current can be determined through the reference voltage, the first observed value and the second observed value. Substituting the expression of the reference current into the above formula (15), formula (16) can be obtained:

[0200] (16)

[0201] Comparing the above formulas (15) and (16), it can be seen that there is no longer a total disturbance, indicating that the second observed value of the extended state observer module can accurately estimate the value of the total disturbance and can eliminate the total disturbance, making the control of the self-disturbance rejection controller for the DC voltage more accurate.

[0202] In one example, a comparative experiment is conducted using the DC voltage control method of the static var generator provided in any of the foregoing embodiments.

[0203] Exemplarily, the initial voltage of the DC side capacitor is set to 500V, and the final value control target is 800V. It can be understood that the initial value of the DC voltage is 500V and the reference voltage is 800V. Now it is necessary to control the DC voltage of the static var generator to change from 500V to 800V.

[0204] Figure 6 For the schematic diagram of the experimental results. As Figure 6 shown, in Figure 6 the solid black line represents the DC voltage change curve of the DC side capacitor during the DC voltage control process using the method provided in the present application; the dashed black line represents the DC voltage change curve of the DC side capacitor during the DC voltage control process using the traditional proportional-integral control (PI control) method.

[0205] Analysis Figure 6 shows that under the method provided in the present application, the overshoot of the DC voltage is smaller and converges to the value represented by the reference voltage faster than the PI control method. Therefore, the effectiveness of the DC voltage control method of the static var generator provided in the present application can be verified. The method provided in the present application can significantly improve the control performance and dynamic compensation speed of the static var generator.

[0206] The control method for the DC voltage of the static var generator provided by the embodiment of the present application determines the reference current by obtaining the target reference voltage and based on the reference voltage, the observed value of the DC voltage by the pre-constructed extended state observer module, and the observed value of the total disturbance; obtains the actual current, and generates a control signal according to the reference current and the actual current; controls the on-state of the switches in the inverter bridge of the static var generator through this control signal, thereby realizing the control of the DC voltage. Among them, the extended state observer module can accurately estimate the DC voltage, adjust the reference current based on the deviation amount, so that the DC voltage follows the reference voltage; the extended state observer module can also accurately estimate and compensate the total disturbance, significantly reducing the influence of model errors, external disturbances, etc. on the control system, and improving the dynamic performance and disturbance resistance of the control system. Among them, by selecting appropriate first gain value, second gain value, and approximate controller gain value, fast response of the DC voltage control can be achieved.

[0207] Figure 7 is a schematic structural diagram of the control device for the DC voltage of the static var generator provided by the present application, as Figure 7 shown, the control device 70 for the DC voltage of the static var generator provided in this embodiment includes:

[0208] A first processing module 701, configured to obtain the reference voltage on the input side of the static var generator, and determine the reference current according to the reference voltage, the first observed value and the second observed value of the extended state observer module; wherein, the first observed value represents the observed value of the DC voltage by the extended state observer module, and the second observed value represents the observed value of the total disturbance by the extended state observer module;

[0209] A second processing module 702, configured to obtain the actual current on the output side of the static var generator, and generate a control signal according to the reference current and the actual current; wherein, the control signal is used to control the on-state of the switches in the static var generator to control the DC voltage of the static var generator.

[0210] In a possible implementation manner, to determine the reference current according to the reference voltage, the first observed value and the second observed value of the extended state observer module, the first processing module 701 is configured to:

[0211] Determine the tracking error according to the reference voltage, the first observed value of the extended state observer module, and a preset proportional coefficient; wherein, the tracking error represents the error between the first observed value and the reference voltage;

[0212] Determine the reference current according to the tracking error, the second observed value of the extended state observer module, and the reciprocal of a preset approximate controller gain value.

[0213] In a possible implementation, the first processing module 701 is further configured to:

[0214] Determine an observation error at the current moment according to the DC voltage of the static var generator at the previous moment and the first observation value of the extended state observer module at the previous moment; wherein, the observation error represents the error between the first observation value and the DC voltage;

[0215] Determine a second observation value of the extended state observer module at the current moment according to the observation error at the current moment and a preset second gain value;

[0216] Determine a first observation value of the extended state observer module at the current moment according to the second observation value at the current moment, the observation error at the current moment, the first gain value, the reference current at the previous moment, and a preset approximate controller gain value.

[0217] In a possible implementation, the first processing module 701 is further configured to:

[0218] Determine the first gain value and the second gain value respectively according to the preset observation bandwidth of the extended state observer module according to a preset first rule; wherein, the first gain value represents the convergence speed of the first observation value of the extended state observer module to the DC voltage; the second gain value represents the convergence speed of the second observation value of the extended state observer module to the total disturbance; the first rule includes the numerical relationship between the observation bandwidth and the first gain value, and the numerical relationship between the observation bandwidth and the second gain value.

[0219] In a possible implementation, the extended state observer module has a characteristic equation and a preset standard equation; the poles of the characteristic equation represent the combined observation influence of the first gain value and the second gain value on the DC voltage and the total disturbance; the poles of the standard equation represent the observation influence of the observation bandwidth on the DC voltage and the total disturbance; wherein, the observation influence represents the convergence speed of the first observation value to the DC voltage and the observation accuracy of the second observation value to the total disturbance;

[0220] To determine the first gain value and the second gain value respectively according to the preset observation bandwidth of the extended state observer module, the first processing module 701 is configured to:

[0221] According to the pole placement method, make the poles of the characteristic equation equal to the poles of the standard equation, so as to determine the first gain value and the second gain value respectively.

[0222] In a possible implementation, to generate a control signal according to the reference current and the actual current, the second processing module 702 is configured to:

[0223] Determine the difference between the reference current and the actual current as the current deviation;

[0224] Determine the voltage control amount according to the current deviation;

[0225] Generate a control signal according to the voltage control amount; wherein, the control signal is a pulse width modulation PWM signal.

[0226] In a possible implementation manner, when the control signal controls the conduction state of the switches in the static var generator to control the DC voltage of the static var generator, the second processing module 702 is configured to:

[0227] Control the conduction state of the switches of the inverter bridge in the static var generator through the control signal to control the actual current to track the reference current;

[0228] When the actual current tracks the reference current, control the charging or discharging of the capacitor on the input side of the static var generator to control the DC voltage of the static var generator.

[0229] The control device for the DC voltage of the static var generator provided in this embodiment can execute the method provided in the above method embodiment, and its implementation principle and technical effect are similar, which will not be elaborated here in this embodiment.

[0230] Figure 8 This is a schematic structural diagram of the static var generator provided in this application. As Figure 8 shown, the static var generator 80 provided in this embodiment includes: at least one processor 801 and a memory 802. Optionally, the static var generator 80 further includes a communication component 803. Among them, the processor 801, the memory 802, and the communication component 803 are connected through a bus 804.

[0231] In a specific implementation process, at least one processor 801 executes the computer execution instructions stored in the memory 802, so that at least one processor 801 executes the above method.

[0232] The specific implementation process of the processor 801 can refer to the above method embodiment, and its implementation principle and technical effect are similar, which will not be elaborated here in this embodiment.

[0233] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU for short), or may also be other general-purpose processors, digital signal processors (DSP for short), application specific integrated circuits (ASIC for short), etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method disclosed in combination with the invention can be directly implemented by the execution of the hardware processor, or can be implemented by the combination of the hardware and software modules in the processor.

[0234] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (Non-volatile Memory, NVM), such as at least one disk memory.

[0235] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of this application is not limited to only one bus or one type of bus.

[0236] This application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0237] This application also provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the processor executes the computer-executable instructions, the above method is implemented.

[0238] The above-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, a magnetic disk or an optical disk. The readable storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0239] An exemplary readable storage medium is coupled to a processor so that the processor can read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an Application Specific Integrated Circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in a device.

[0240] The division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed between each other can be through some interfaces, and the indirect couplings or communication connections of devices or units can be in electrical, mechanical or other forms.

[0241] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0242] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0243] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0244] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments; and the foregoing storage medium includes: various media such as ROM, RAM, magnetic disk, or optical disk that can store program codes.

[0245] Finally, it should be noted that: after considering the specification and practicing the invention disclosed herein, those skilled in the art will readily conceive of other embodiments of the present invention. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include known common knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A control method for the DC voltage of a static var generator, characterized in that, A processor applied to a static var generator, comprising: Obtain a reference voltage on the input side of the static var generator, and determine a reference current according to the reference voltage, a first observation value and a second observation value of an extended state observer module; wherein, the first observation value represents the observation value of the direct current voltage by the extended state observer module, and the second observation value represents the observation value of the total disturbance by the extended state observer module; Obtain an actual current on the output side of the static var generator, and generate a control signal according to the reference current and the actual current; wherein, the control signal is used to control the conduction state of a switch in the static var generator to control the direct current voltage of the static var generator.

2. The method according to claim 1, characterized in that, Determining a reference current according to the reference voltage, a first observation value and a second observation value of an extended state observer module, comprising: Determine a tracking error according to the reference voltage, the first observation value of the extended state observer module and a preset proportionality coefficient; wherein, the tracking error represents the error between the first observation value and the reference voltage; Determine a reference current according to the tracking error, the second observation value of the extended state observer module and the reciprocal of a preset approximate controller gain value.

3. The method according to claim 1, characterized in that The method further comprises: Determine an observation error at the current moment according to the direct current voltage of the static var generator at the previous moment and the first observation value of the extended state observer module at the previous moment; wherein, the observation error represents the error between the first observation value and the direct current voltage; Determine the second observation value of the extended state observer module at the current moment according to the observation error at the current moment and a preset second gain value; Determine the first observation value of the extended state observer module at the current moment according to the second observation value at the current moment, the observation error at the current moment, a first gain value, the reference current at the previous moment and a preset approximate controller gain value.

4. The method according to claim 3, wherein The method further comprises: Determine the first gain value and the second gain value respectively according to a preset observation bandwidth of the extended state observer module according to a preset first rule; wherein, the first gain value represents the convergence speed of the first observation value of the extended state observer module towards the direct current voltage; the second gain value represents the convergence speed of the second observation value of the extended state observer module towards the total disturbance; the first rule includes the numerical relationship between the observation bandwidth and the first gain value, and the numerical relationship between the observation bandwidth and the second gain value.

5. The method according to claim 4, wherein The extended state observer module has a characteristic equation and a preset standard equation; the poles of the characteristic equation represent the combined observation influence of the first gain value and the second gain value on the direct current voltage and the total disturbance; the poles of the standard equation represent the observation influence of the observation bandwidth on the direct current voltage and the total disturbance; wherein, the observation influence represents the convergence speed of the first observation value towards the direct current voltage and the observation accuracy of the second observation value for the total disturbance; Determine the first gain value and the second gain value respectively according to the observation bandwidth preset by the expansion state observation module, including: According to the pole placement method, make the poles of the characteristic equation equal to the poles of the standard equation, so as to determine the first gain value and the second gain value respectively.

6. The method according to any one of claims 1-5, characterized in that Generate a control signal according to the reference current and the actual current, including: Determine the difference between the reference current and the actual current as the current deviation; Determine the voltage control amount according to the current deviation; Generate a control signal according to the voltage control amount; wherein, the control signal is a pulse width modulation PWM signal.

7. The method according to any one of claims 1-5, characterized in that, When the control signal controls the conduction state of the switch in the static var generator to control the DC voltage of the static var generator, it includes: Control the conduction state of the switch of the inverter bridge in the static var generator through the control signal to control the actual current to track the reference current; When the actual current tracks the reference current, control the charging or discharging of the capacitor on the input side of the static var generator to control the DC voltage of the static var generator.

8. A control device for the DC voltage of a static var generator, characterized in that, Including: A first processing module, configured to obtain a reference voltage on the input side of the static var generator, and determine a reference current according to the reference voltage, the first observation value and the second observation value of the expansion state observation module; wherein, the first observation value represents the observation value of the expansion state observation module for the DC voltage, and the second observation value represents the observation value of the expansion state observation module for the total disturbance; A second processing module, configured to obtain the actual current on the output side of the static var generator, and generate a control signal according to the reference current and the actual current; wherein, the control signal is used to control the conduction state of the switch in the static var generator to control the DC voltage of the static var generator.

9. A static var generator, characterized in that, Including: A memory, a processor; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory, so that the processor executes the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, Computer execution instructions are stored in the computer-readable storage medium, and when the computer execution instructions are executed by the processor, they are used to implement the method according to any one of claims 1-7.

11. A computer program product, characterized in that, Including a computer program, which when executed by the processor implements the method according to any one of claims 1-7.

Images