Network construction type three-phase imbalance compensation control method, system, equipment and medium

Abstract

The invention relates to the technical field of electric energy quality treatment of an electric power system, and discloses a network construction type three-phase imbalance compensation control method, system, equipment and medium, which comprises the following steps that: a network construction type control strategy is adopted, so that a converter autonomously generates pure chord and three-phase symmetrical internal potential, and a voltage transformer does not need to be arranged on a transformer area line; the engineering implementation is simplified; through cooperative control of a direct current stabilizer (including a bidirectional Boost and energy recovery circuit) and small-capacity energy storage, the voltage of a direct current side coupling capacitor is quickly stabilized, the dynamic response performance is improved, the self-starting and maintenance-free capability of equipment is realized, and the system reliability is remarkably improved. The stability problem of a traditional SVG under a weak power grid is effectively solved, and an efficient, reliable and easy-to-implement three-phase imbalance and harmonic comprehensive treatment scheme is provided for a power distribution area through an innovative system topology and control method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system power quality treatment, and particularly relates to a network configuration type three-phase imbalance compensation control method, system, device and medium. BACKGROUND

[0002] In the 380V low-voltage distribution area, due to the existence of single-phase load, three-phase imbalance is more prominent, and three-phase imbalance can lead to high and low voltage problems and distribution transformer heavy overload, especially with the access of a large number of single-phase distributed photovoltaic to the distribution area, the problem is more prominent. Its harm is reflected in: 1. Increase the power loss on the line. When the three-phase load of the distribution network is balanced, the active power and reactive power of each phase are equal, and the line loss is proportional to the sum of the squares of the currents of each phase. When the three-phase load is unbalanced, the total active and reactive power is unchanged, and the currents of each phase are not equal. In this case, the sum of the squares of the three-phase currents is greater than that when the three-phase load is balanced. In addition, when the three-phase load is unbalanced, the neutral line current is not zero, and active loss will occur in the neutral line. In summary, unbalanced load will increase the active loss of the entire network.

[0003] 2. Reduce the output of the distribution transformer. When the three-phase load of the system is unbalanced, the heavy load phase of the distribution transformer will be full load or even overload, and the light load phase will have surplus capacity, thereby reducing the output of the transformer.

[0004] 3. Cause three-phase voltage asymmetry, leading to high and low voltage coexistence problem.

[0005] There are mainly two ways to solve the above problems: one is to split the load of the original distribution area by building a new distribution area, which shortens the power supply radius and solves the problems of heavy overload and low voltage of the original distribution transformer. Due to the involvement of a series of links and management processes such as project approval, project research, material procurement and project construction in the new distribution area of the power grid company, this solution has poor timeliness and high investment cost. The other way is to install imbalance treatment devices, including load commutation devices, traditional reactive power compensation devices and SVG, but the load commutation device needs large-scale modification, which has high investment and low cost-effectiveness compared with traditional new distribution area; SVG has high operation and maintenance cost and is not suitable for large-scale distribution area. SUMMARY

[0006] In view of the above existing problems, the present application provides a network configuration type three-phase imbalance compensation control method, system, device and medium.

[0007] Therefore, the technical problems solved by the present application are: (1) the low reliability of traditional SVG, which has a bidirectional Boost circuit and a small capacity energy storage device to provide self-starting capability for SVG. (2) The network configuration control strategy is adopted to avoid the stability problem of weak power grid.

[0008] To solve the above technical problems, the application provides the following technical scheme, a network type three-phase unbalance compensation control method, comprising: using a network type control strategy, generating a three-phase sinusoidal internal potential signal, the amplitude of the internal potential is determined based on a rated voltage and a dynamic voltage recovery term; The output voltage of the network type converter is controlled, the internal potential signal is tracked with high precision, a proportional-integral-derivative controller is used to control the coupling capacitor voltage of the network type converter; Through the bidirectional Boost circuit in the DC stabilizer, a modulation signal is generated according to the error of the coupling capacitor voltage and the injected current, and the voltage is stabilized; Through the energy recovery circuit in the DC stabilizer, when the coupling capacitor voltage exceeds the threshold value, the small-capacity energy storage is triggered to charge.

[0009] As a preferred scheme of the network type three-phase unbalance compensation control method, wherein: the dynamic voltage recovery term includes, the effective value of the three-phase output voltage of the network type converter is averaged, the obtained average value is subtracted from the rated voltage, and then a proportional integral controller is used to generate; The effective value of the three-phase output voltage: The average value: Wherein, is the voltage recovery term, is the rated phase voltage, is the real-time effective value of the three-phase unbalance treatment device, , and is the effective value of the three-phase output voltage of the three-phase unbalance treatment device a, b and c, and is the proportional coefficient, and s refers to the Laplace operator.

[0010] As a preferred scheme of the network type three-phase unbalance compensation control method, wherein: the high-precision tracking internal potential signal includes, using proportional-resonant control in the abc stationary coordinate system, the transfer function of the resonant part is, Wherein, is the fundamental angular frequency, is the rated frequency, is the harmonic number, for the fundamental wave, the value is 1, is the bandwidth angular frequency, and the fundamental wave is taken is the phase compensation angle of the hth harmonic, is the resonance coefficient.

[0011] As a preferred scheme of the network type three-phase unbalance compensation control method, the control of the coupling capacitor voltage of the network type converter comprises using PID control of the coupling capacitor C dc Stable in the range of the command value, Wherein, is the initial phase angle of the a-phase internal potential, is the proportional coefficient, is the integral coefficient, is the differential coefficient, is the coupling capacitor command voltage, is the real-time voltage of the coupling capacitor; At the same time, a low-pass filter The differential element is processed to avoid amplifying high-frequency noise.

[0012] As a preferred scheme of the network type three-phase unbalance compensation control method, the control of the bidirectional Boost circuit comprises subtracting the real-time voltage measurement of the coupling capacitor from the command value, introducing the injection current integral term of the coupling capacitor into the feedback, normalizing with the DC command voltage value, and then generating a modulation wave signal through a proportional-integral controller , generating a PWM signal to drive the transistor module Sa to act, Wherein, is the injection current of the coupling capacitor, are the proportional coefficient and the integral coefficient of the proportional-integral controller, respectively.

[0013] As a preferred scheme of the network type three-phase unbalance compensation control method, the generation of the modulation signal according to the error of the coupling capacitor voltage and the injection current, and the stabilization of the voltage comprises comparing the real-time voltage of the coupling capacitor with the threshold value If it is greater than the threshold value, the transistor Sb is triggered to conduct, Wherein, is the margin coefficient.

[0014] As a preferred scheme of the network type three-phase unbalance compensation control method, it further comprises comparing the state of charge SoC of the small-capacity energy storage with the minimum threshold value SoC min When it is lower than the minimum threshold value, the small-capacity energy storage is charged by the converter; Comparing the real-time state of charge SoC of the small-capacity energy storage with the target state of charge The size of the SoC is less than The latching transistor Sc and Sd are turned on, and the transistor Sb is turned on to charge the small-capacity energy storage, and the above process continues until the small-capacity energy storage SoC reaches .

[0015] The application provides a network-structured three-phase imbalance compensation control system.

[0016] As a preferred scheme of the network-structured three-phase imbalance compensation control system, the network-structured three-phase imbalance compensation control system comprises a network-structured converter module, a DC voltage stabilization module and a central control module. The network-structured converter module is responsible for power conversion and generates a compensation voltage according to a control instruction to directly govern three-phase imbalance and harmonic problems on the power grid side. The DC voltage stabilization module is responsible for stabilizing the DC side working voltage of the system and managing the energy of the small-capacity energy storage to provide power support and energy buffering for the converter module. The central control module calculates an internal potential instruction signal according to the state of the power grid, controls the output voltage of the network-structured converter module to accurately track the instruction, generates a signal to control each part of the DC voltage stabilization module to maintain the stability of the DC voltage, and manages the energy state of the small-capacity energy storage.

[0017] The application provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a network-structured three-phase imbalance compensation control method when executing the computer program.

[0018] The application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of a network-structured three-phase imbalance compensation control method when executed by a processor.

[0019] The application has the advantages that the device does not need to install a voltage transformer on an existing transformer area line, thereby eliminating the trouble and having higher stability in a weak power grid (i.e., when the transformer area line is long). The small-capacity energy storage is configured on the DC side of the three-phase imbalance treatment device to provide rapid power support for the coupling capacitor, improve the voltage stability of the coupling capacitor, and also build the coupling capacitor voltage when the three-phase imbalance treatment device fails to realize self-starting of the entire device and improve the maintenance-free ability of the entire device.

[0020] The pre-stage direct current stabilizer circuit has double functions, in addition to charging the coupling capacitor by using the Boost circuit and stabilizing the voltage value of the coupling capacitor, the energy recovery circuit can charge the small capacity energy storage when the voltage of the coupling capacitor is high, and quickly adjust the voltage of the coupling capacitor.

[0021] The pure sine wave is directly generated as the instruction voltage of the grid-connected converter, the grid-connected converter output voltage is controlled to track the instruction voltage with high precision, the voltage at the grid-connected point of the three-phase imbalance comprehensive treatment device is a three-phase voltage with extremely low three-phase symmetrical harmonic content, and the integral of the coupling capacitor injection current is introduced into the control of the direct current stabilizer Boost circuit, so that the voltage control effect of the coupling capacitor is better. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 A grid-connected three-phase imbalance compensation control device structure schematic diagram is provided for an embodiment of the present application.

[0024] Figure 2 A voltage tracking schematic diagram of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0025] Figure 3 An experimental device schematic diagram of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0026] Figure 4 A three-phase voltage without compensation in scenario 1 of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0027] Figure 5 A three-phase voltage with compensation in scenario 1 of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0028] Figure 6 A three-phase voltage without compensation in scenario 2 of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0029] Figure 7 A three-phase voltage with compensation in scenario 2 of a grid-connected three-phase imbalance compensation control method is provided for an embodiment of the present application.

[0030] Figure 8 Scenario 3 three-phase voltage without compensation for a network type three-phase unbalance compensation control method provided by one embodiment of the present application.

[0031] Figure 9 Scenario 3 three-phase voltage with compensation for a network type three-phase unbalance compensation control method provided by one embodiment of the present application.

[0032] Figure 10 Scenario 4 three-phase voltage without compensation for a network type three-phase unbalance compensation control method provided by one embodiment of the present application.

[0033] Figure 11 Scenario 4 three-phase voltage without compensation for a network type three-phase unbalance compensation control method provided by one embodiment of the present application.

[0034] Figure 12 Three-phase load diagram for charging small-capacity energy storage for a network type three-phase unbalance compensation control method provided by one embodiment of the present application. DETAILED DESCRIPTION

[0035] To make the above objectives, features and advantages of the present application more apparent and understandable, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should fall within the scope of protection of the present application.

[0036] Embodiment 1, as the first embodiment of the present application, provides a network type three-phase unbalance compensation control method, comprising: S1: using a network type control strategy to generate a three-phase sinusoidal internal potential signal, the amplitude of the internal potential being determined based on a rated voltage and a dynamic voltage recovery term.

[0037] S2: controlling the output voltage of the network type converter, high-precision tracking the internal potential signal, using a proportional-integral-derivative controller to control the coupling capacitor voltage of the network type converter.

[0038] S3: generating a modulation signal according to the error of the coupling capacitor voltage and the injected current through the bidirectional Boost circuit in the DC stabilizer, stabilizing the voltage.

[0039] S4: triggering the charging of the small-capacity energy storage when the coupling capacitor voltage exceeds the threshold value through the energy recovery circuit in the DC stabilizer.

[0040] It should be noted that the method corresponds to a device composed of a small-capacity energy storage DC stabilizer and a network type converter part, and the structure diagram is as followsFigure 1 The direct current stabilizer is composed of a forward Boost circuit (composed of a small-capacity energy storage BL, an inductor L1, a transistor Sc, and a coupling capacitor Cdc) and an energy recovery circuit (composed of a resistor Rb, a transistor Sb, a buffer capacitor Cb, and a transistor anti-parallel diode module Sd). The direct current stabilizer functions to quickly stabilize the coupling capacitor voltage, and creates conditions for the normal operation of the grid-forming converter. The grid-forming converter (which can be two-level or three-level, and the schematic diagram shows two-level) includes a, b, and c three-phase bridge arms and a neutral line corresponding bridge arm, and adopts an LC (inductor-capacitor) filter circuit, in which L fa , L fb , and L fc are filter inductors of a, b, and c three phases, C fa , C fb , and C fc are filter capacitors of a, b, and c three phases. The small-capacity energy storage BL functions to charge the coupling capacitor Cdc through reasonable control to stabilize the voltage of the coupling capacitor Cdc, improve the reliability of the grid-forming power quality compensation system, and reduce the cost by using a small-capacity energy storage. The use of the grid-forming converter can eliminate the installation of a current transformer on the transformer area line, and is convenient for engineering use.

[0041] Embodiment 2, referring to Figure 1 and Figure 2 , is an embodiment of the present application, based on the above embodiment, a grid-forming three-phase unbalance compensation control method is provided.

[0042] Further, in the embodiment of the present application, step S1 adopts a grid-forming control strategy to generate a three-phase sinusoidal internal potential signal, and the amplitude of the internal potential is determined based on a rated voltage and a dynamic voltage recovery term. The specific steps include: Generating an instruction voltage, the grid-forming converter can autonomously generate an internal potential, that is, as shown in formulas (1a), (1b), and (1c).

[0043] (1a) (1b) (1c) In the formula, V is an internal potential instruction signal of a, b, and c three phases of the grid-forming converter, is an initial phase angle of the a-phase internal potential, and π is a circular constant.

[0044] The key is how to generate the amplitude V and the a-phase internal potential phase angle θ (a, b, and c phase internal potential phase angles lag in turn , thus the phase-a internal voltage phase angle is obtained, the phase-b and phase-c internal voltage phase angles are also obtained naturally. In this embodiment, the internal voltage is calculated according to formula (2), wherein is the rated phase voltage, is a voltage recovery term. For a low-voltage area with a line voltage of 380 V, the phase voltage is 220 V, and thus . is used to compensate for the voltage drop caused by the load current.

[0045] (2) For control, the difference between and the rated phase voltage is taken and then passed through a PI link to generate , which is calculated as shown in formula (5), wherein the proportional coefficient and can be set by using a mature method. In formula (3), is the real-time effective value of the three-phase imbalance treatment device, that is, the effective values of the three-phase output voltages of the three-phase imbalance treatment device a, b, and c , and are averaged, as shown in formula (4): (3) (4) wherein s indicates a Laplace operator.

[0046] Furthermore, in the embodiment of the application, step S2 controls the output voltage of the grid-forming converter, high-precision tracks the internal voltage signal, adopts a proportional-integral-derivative controller, and controls the coupling capacitor voltage of the grid-forming converter. The specific steps include: The voltage tracking link can adopt a conventional mature single-loop control or a voltage outer loop and current inner loop control. The control can adopt an abc three-phase stationary coordinate system, a stationary coordinate system, and a dq0 rotating coordinate system.

[0047] A proportional-resonant control in the abc stationary coordinate system is adopted. The transfer function of the resonant part is shown in formula (5): (5) In formula (5), is the fundamental angular frequency (wherein is the rated frequency of the grid), is the harmonic order (the first harmonic, that is, the fundamental, is also referred to as a harmonic for the convenience of description), for the fundamental, the value of the number is 1, is a bandwidth angular frequency, which can be the fundamental is a phase compensation angle of the hth harmonic, is the resonance coefficient.

[0048] The voltage outer loop and current inner loop control are adopted, wherein RCi (i=1, 3, 5, 6…) represents the resonance control of the i-th harmonic, and has a transfer function shown in formula (5).

[0049] The control target of the coupling capacitor is to ensure that Cdc is basically stable at the instruction value nearby, to lay a foundation for the normal operation of the network type three-phase unbalanced compensation device, and the control can adopt PID control, such as formula (6), wherein the proportional coefficient , the integral coefficient and the differential coefficient can be set according to the traditional method.

[0050] (6) In formula (6), a low-pass filter is used to process the differential link to avoid amplification of high-frequency noise.

[0051] Further, in the embodiment of the application, step S3 generates a modulation signal according to the error of the coupling capacitor voltage and the injected current through the bidirectional Boost circuit in the DC stabilizer, and stabilizes the voltage, and the specific steps include: The voltage stabilization control includes the control of the Boost circuit and the control of the energy recovery circuit. The control method of the Boost circuit is to subtract the real-time voltage measurement value of the coupling capacitor from the instruction value, introduce the integral term of the injected current of the coupling capacitor into the feedback, then normalize with the DC instruction voltage value, and then generate a modulation wave signal through a proportional-integral controller , further generate a PWM signal to drive the transistor module Sa to act, as shown in formula (7), (7) , wherein is the injected current of the coupling capacitor, and the integral coefficient of the proportional-integral controller, respectively.

[0052] The purpose of the energy recovery control is to charge the coupling capacitor to the energy storage when the coupling capacitor voltage exceeds a certain threshold, so as to quickly reduce the coupling capacitor voltage and improve the control effect of the coupling capacitor voltage. The real-time voltage of the coupling capacitor is compared with a certain threshold , if greater than the threshold, the transistor Sb is turned on, as shown in formula (8) (8) In formula (8) , is the instruction voltage of the coupling capacitor, is a margin coefficient, generally less than 5%.

[0053] Further, in the embodiments of the present application, step S4 triggers the charging of the small-capacity energy storage through the energy recovery circuit in the DC stabilizer when the coupling capacitor voltage exceeds the threshold value, and the specific steps include: comparing the state of charge SoC of the small-capacity energy storage with the minimum threshold value min When the threshold value is lower, the small-capacity energy storage is charged by the converter. The method is to compare the real-time state of charge SoC of the small-capacity energy storage with the target state of charge When SoC is less than , the transistors Sc and Sd are locked and the transistor Sb is turned on to charge the small-capacity energy storage. The above process continues until the SoC of the small-capacity energy storage reaches .

[0054] Embodiment 3, which is different from the first two embodiments, is a third embodiment of the present application. The embodiment also provides a network-forming three-phase imbalance compensation control system, which comprises a network-forming converter module, a DC voltage stabilizing module, and a central control module. The network-forming converter module is responsible for performing power conversion and generating a compensation voltage according to a control instruction to directly govern the three-phase imbalance and harmonic problems on the grid side. The DC voltage stabilizing module is responsible for stabilizing the DC side operating voltage of the system and managing the energy of the small-capacity energy storage to provide power support and energy buffer for the converter module. The central control module calculates an internal potential instruction signal according to the grid state, controls the output voltage of the network-forming converter module to accurately track the instruction, generates a signal to control each part of the DC voltage stabilizing module to maintain the stability of the DC voltage, and manages the energy state of the small-capacity energy storage.

[0055] The embodiment also provides an electronic device, which comprises a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions to implement a network-forming three-phase imbalance compensation control method as proposed in the above embodiment.

[0056] The embodiment also provides a storage medium having a computer program stored thereon, which is executed by a processor to implement a network-forming three-phase imbalance compensation control method as proposed in the above embodiment.

[0057] The storage medium proposed in the embodiment and the network-forming three-phase imbalance compensation control method proposed in the above embodiment belong to the same inventive concept, and the technical details not described in detail in the embodiment can be referred to the above embodiment, and the embodiment has the same beneficial effects as the above embodiment.

[0058] Those skilled in the art can clearly understand the present application by the above description of the embodiments, and the present application can be realized by software and necessary general hardware, and of course, can also be realized by hardware. Based on such understanding, the technical solutions of the present application or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a floppy disk, a read-only memory (ROM), a random access memory (RAM), a FLASH, a hard disk, or an optical disk, and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods of various embodiments of the present application.

[0059] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limited. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

[0060] Embodiment 4, refer to Figures 3-11 For an embodiment of the present application, a network construction type three-phase unbalance compensation control method is verified.

[0061] Three-phase unbalance compensation, three-phase 380V area with unbalanced load and a three-phase uncontrolled rectifier, such as Figure 3

[0062] Table 1 Voltage unbalance and harmonic conditions under four scenarios without compensation

[0063] Table 2 Voltage unbalance and harmonic conditions under four scenarios with compensation by the device of the present application ​

Claims

1. A network-type three-phase imbalance compensation control method, characterized in that: include, A grid-type control strategy is adopted to generate a three-phase sinusoidal internal potential signal. The amplitude of the internal potential is determined based on the rated voltage and a dynamic voltage recovery term. To control the output voltage of the grid converter, the internal potential signal is tracked with high precision. A proportional-integral-derivative controller is used to control the coupling capacitor voltage of the grid converter. The bidirectional Boost circuit in the DC ballast generates a modulation signal based on the error of the coupling capacitor voltage and the injected current to stabilize the voltage. The energy recovery circuit in the DC ballast triggers charging of the small-capacity energy storage when the voltage of the coupling capacitor exceeds a threshold.

2. The three-phase imbalance compensation control method of the grid type as described in claim 1, characterized in that: The dynamic voltage recovery term includes averaging the effective value of the three-phase output voltage of the grid converter, and then generating the average value by subtracting the rated voltage from the average value using a proportional-integral controller. The effective value of the three-phase output voltage: The average value: in, For voltage recovery, Rated phase voltage, This represents the real-time effective value of the three-phase imbalance control device. , and The values ​​are the effective values ​​of the three-phase output voltages (a, b, and c) of the three-phase imbalance correction device. and s is the proportionality coefficient, and s refers to the Laplace operator.

3. The three-phase imbalance compensation control method of network type as described in claim 2, characterized in that: The high-precision tracking internal potential signal includes proportional resonance control in an abc stationary coordinate system, where the transfer function of the resonant part is... in, The fundamental angular frequency, For the rated frequency, This represents the harmonic order; for the fundamental frequency, the value is 1. The bandwidth angular frequency is taken as the fundamental frequency. The phase compensation angle for the h-th harmonic. It is the resonance coefficient.

4. The three-phase imbalance compensation control method of the grid type as described in claim 3, characterized in that: The voltage of the coupling capacitor in the controlled grid converter includes the voltage of the coupling capacitor C controlled by PID. dc Stable within the range of the instruction value, in, Let be the initial phase angle of the internal potential of phase a. This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients. It is the coupling capacitor command voltage. This represents the real-time voltage of the coupling capacitor. Simultaneously employing a low-pass filter The differential component is processed to avoid amplifying high-frequency noise.

5. The three-phase imbalance compensation control method of the grid type as described in claim 4, characterized in that: The control of the bidirectional Boost circuit includes subtracting the real-time measured voltage value of the coupling capacitor from the command value, simultaneously introducing the integral term of the injected current of the coupling capacitor into the feedback, normalizing it with the DC command voltage value, and then generating a modulated wave signal through a proportional-integral controller. It generates a PWM signal to drive the transistor module Sa to operate. in, This refers to the injected current into the coupling capacitor. These are the proportional coefficient and integral coefficient of the proportional-integral controller, respectively.

6. The three-phase imbalance compensation control method of the grid type as described in claim 5, characterized in that: The step of generating a modulation signal based on the error of the coupling capacitor voltage and the injected current, and stabilizing the voltage, includes adjusting the real-time voltage of the coupling capacitor. and threshold In comparison, if the value is greater than or equal to the threshold, then transistor Sb is triggered to conduct. in, It is the margin coefficient.

7. The three-phase imbalance compensation control method of a grid-type structure as described in claim 6, characterized in that: This also includes comparing the state-of-charge SoC with small-capacity energy storage with the size of the SoC with the minimum threshold. min When the energy level is below the minimum threshold, the small-capacity energy storage is charged using a converter. Comparing real-time state of charge (SOC) and target state of charge for small-capacity energy storage Size, when SoC is smaller The blocking transistors Sc and Sd, and the turning transistor Sb, charge the small-capacity energy storage. This process continues until the small-capacity energy storage SoC reaches its maximum capacity. .

8. A network-type three-phase imbalance compensation control system, employing the network-type three-phase imbalance compensation control method as described in any one of claims 1 to 7, characterized in that, include: Network-type converter module, DC voltage stabilization module and central control module; The grid-type converter module is responsible for performing power conversion and generating compensation voltage according to control commands, directly addressing the three-phase imbalance and harmonic problems on the grid side. The DC voltage stabilization module is responsible for stabilizing the DC-side operating voltage of the system and managing the energy of the small-capacity energy storage, providing power support and energy buffering for the converter module. The central control module calculates the internal potential command signal based on the grid status, controls the output voltage of the grid-type converter module to accurately track the command, generates signals to control various circuits of the DC voltage stabilization module to maintain DC voltage stability, and manages the energy status of small-capacity energy storage in a coordinated manner.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the grid-type three-phase imbalance compensation control method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the grid-type three-phase imbalance compensation control method according to any one of claims 1 to 7.

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