Power grid compensation method, device, equipment and program product

Abstract

The invention is suitable for the technical field of power grids, and provides a power grid compensation method, device and equipment and a program product. The method comprises the steps of obtaining sampling voltage and sampling current of a power grid; determining a fundamental wave positive sequence phase of the power grid according to the sampling voltage; determining a compensation current instruction corresponding to the power grid according to the fundamental wave positive sequence phase and the sampling current; determining a compensation current reference value according to the compensation current instruction; and performing reactive compensation and harmonic compensation on the power grid according to the compensation current reference value. According to the power grid compensation method provided by the invention, reactive compensation and harmonic compensation can be performed on the power grid at the same time, the technical problem that reactive compensation and harmonic compensation cannot be performed on the power grid at the same time in the prior art is solved, and the compensation effect on the power grid is improved.

Description

Technical Field

[0001] This application belongs to the field of power grid technology, and in particular relates to a power grid compensation method, device, equipment and program product. Background Technology

[0002] Currently, there are a large amount of harmonic power and reactive power in the power grid. These harmonic and reactive power not only aggravate the line losses and reduce the power factor of the power grid, but also reduce the power supply quality, interfere with the operation of precision compensation equipment, and cause malfunctions of protection devices, threatening the economic, safe and stable operation of the power grid.

[0003] To reduce the negative impact of harmonic and reactive power on the power grid, it is necessary to compensate for these two factors. However, current technologies typically only compensate for reactive power or harmonics, not both simultaneously, thus reducing the effectiveness of the compensation. Summary of the Invention

[0004] In view of this, embodiments of this application provide a power grid compensation method, apparatus, equipment, and program product to solve the technical problem of poor power grid compensation effect in the prior art.

[0005] In a first aspect, embodiments of this application provide a power grid compensation method, comprising: Obtain the sampled voltage and sampled current of the power grid; The fundamental positive sequence phase of the power grid is determined based on the sampled voltage. Based on the fundamental positive sequence phase and the sampled current, the corresponding compensation current command for the power grid is determined; Determine the reference value of the compensation current according to the compensation current command; Based on the aforementioned compensation current reference value, reactive power compensation and harmonic compensation are performed on the power grid.

[0006] Optional, Optionally, determining the fundamental positive sequence phase of the power grid based on the sampled voltage includes: The positive-sequence component of the fundamental voltage of the power grid is determined by the positive-sequence separation phase-locked loop based on the sampled voltage, and the positive-sequence component of the fundamental voltage is phase-locked by the positive-sequence separation phase-locked loop. The fundamental positive-sequence phase is determined based on the phase-locked positive-sequence component of the fundamental voltage.

[0007] Optionally, determining the fundamental positive-sequence component of the power grid based on the sampled voltage includes: The fundamental voltage signal is phase-shifted by an all-pass filter based on the fundamental rated frequency of the fundamental voltage signal corresponding to the sampling voltage. The target fundamental signal is obtained by filtering out the interference of high-frequency harmonics on the phase-shifted fundamental voltage signal through a low-pass filter. Based on the target fundamental signal, determine the positive sequence component of the fundamental voltage.

[0008] Optionally, determining the compensation current command corresponding to the power grid based on the fundamental positive sequence phase and the sampled current includes: Based on the fundamental positive sequence phase, the first three-phase current corresponding to the sampling current is subjected to coordinate transformation to obtain the dq-axis current of the sampling current in the synchronous rotating coordinate system. The dq-axis current is filtered using a low-pass filter to determine the DC component of the dq-axis. Based on the fundamental positive sequence phase, the DC component of the dq axis is subjected to inverse coordinate transformation to obtain the second three-phase current; The compensation current command is determined based on the first three-phase current and the second three-phase current.

[0009] Optionally, determining the compensation current command based on the first three-phase current and the second three-phase current includes: Determine the first a-phase current, the first b-phase current, and the first c-phase current corresponding to the first three-phase current; Determine the second a-phase current, the second b-phase current, and the second c-phase current corresponding to the second and third phase currents; The phase a current difference is determined based on the first phase a current and the second phase a current; The phase b current difference is determined based on the first phase b current and the second phase b current; The c-phase current difference is determined based on the first c-phase current and the second c-phase current; The compensation current command is determined based on the current difference of phase a, the current difference of phase b, and the current difference of phase c.

[0010] Optionally, determining the compensation current reference value according to the compensation current command includes: Obtain the composite compensation controller; The composite compensation controller determines the reference value of the compensation current based on the compensation current command and the control command corresponding to the outer loop compensation controller.

[0011] Optionally, the acquisition of the composite compensation controller includes: Obtain the initial repetitive compensation controller; the integration processing method of the initial repetitive compensation controller is ideal integration; The integral processing method of the initial repetitive compensation controller is modified to quasi-integral processing to obtain the target repetitive compensation controller; The composite compensation controller is obtained by combining the target repetitive compensation controller with the proportional-integral compensation controller.

[0012] Secondly, embodiments of this application provide a power grid compensation device, comprising: The acquisition unit is used to acquire the sampled voltage and sampled current of the power grid; The first determining unit is used to determine the fundamental positive sequence phase of the power grid based on the sampled voltage. The second determining unit is used to determine the compensation current command corresponding to the power grid based on the fundamental positive sequence phase and the sampled current. The third determining unit is used to determine the compensation current reference value according to the compensation current command; The compensation unit is used to perform reactive power compensation and harmonic compensation on the power grid based on the compensation current reference value.

[0013] Thirdly, embodiments of this application provide a compensation device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the power grid compensation method as described in any of the first aspects above.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the power grid compensation method as described in any of the first aspects above.

[0015] Fifthly, embodiments of this application provide a computer program product that, when run on a control device, causes the control device to perform the steps of the power grid compensation method as described in any of the first aspects above.

[0016] The power grid compensation method, apparatus, equipment, and program product provided in this application have the following beneficial effects: In the power grid compensation method provided in this application embodiment, the sampled voltage and sampled current of the power grid are first obtained. Then, based on the sampled voltage, the fundamental positive sequence phase of the power grid is determined. Based on the fundamental positive sequence phase and the sampled current, the corresponding compensation current command for the power grid is determined. Next, based on the compensation current command, a compensation current reference value is determined. Finally, based on the compensation current reference value, reactive power compensation and harmonic compensation are performed on the power grid. The power grid compensation method provided in this application can simultaneously perform reactive power compensation and harmonic compensation on the power grid, solving the technical problem in the prior art that it is impossible to simultaneously perform reactive power compensation and harmonic compensation on the power grid, and improving the effect of power grid compensation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the implementation of the power grid compensation method provided in this application embodiment; Figure 2 This is a schematic diagram of a method for determining the compensation current command corresponding to the power grid, provided in an embodiment of this application. Figure 3 This is a schematic diagram of the structure of a composite compensation controller provided in an embodiment of this application; Figure 4 A schematic diagram of the structure of a power grid compensation device provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of a compensation device provided in an embodiment of this application. Detailed Implementation

[0019] It should be noted that the terminology used in the embodiments of this application is only for explaining specific embodiments of this application and is not intended to limit this application. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, "at least one" or "one or more" means one, two or more. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0020] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0021] In the existing technology, existing compensation equipment can usually only perform reactive power compensation or harmonic compensation for the power grid.

[0022] For example, a passive power filter is a compensation device that can compensate for harmonics in the power grid. Its working principle is to filter out harmonics or prevent their propagation by adding additional impedance branches to the system, thereby reducing the harmonic content injected into the power grid. Passive filters typically have large capacity and low cost, but their compensation characteristics are easily affected by grid impedance, they are prone to resonance with the grid, and their compensation accuracy and flexibility are poor. In practical applications, passive power filters cannot provide reactive power compensation for the power grid.

[0023] For example, synchronous condensers, static var compensators (SVCs), and static synchronous compensators (SRCs) are all compensation devices capable of reactive power compensation for the power grid. Synchronous condensers work by adjusting the excitation current of a synchronous motor to compensate for reactive power; however, they suffer from drawbacks such as large size, difficult maintenance, mechanical noise, and slow response. Furthermore, in practical applications, synchronous condensers cannot compensate for harmonics in the power grid. Static var compensators (SVCs) work by combining thyristor-controlled switching reactors (TCRs) and switching capacitors (TSCs) to achieve reactive power regulation. They offer large compensation capacity but require a large footprint, have low compensation accuracy, and generate harmonics, thus also failing to compensate for harmonics in the power grid. Static synchronous compensators (SMCs) work by using pulse width modulation (PWM) technology to control the amplitude of the output voltage and the grid voltage through a voltage source converter to achieve reactive power regulation. This is currently the mainstream technology, offering advantages such as small size, fast response, and continuous dynamic reactive power adjustment. However, in practical applications, because SMCs cannot accurately detect harmonics in the power grid and cannot track AC signals without steady-state error, they also cannot compensate for harmonics in the power grid.

[0024] Based on this, embodiments of this application provide a power grid compensation method for simultaneously performing reactive power compensation and harmonic compensation on the power grid.

[0025] The power grid compensation method provided in this application can be implemented by a power grid compensation device. This power grid compensation device can execute each step of the power grid compensation method provided in this application.

[0026] The power grid compensation method provided in this application can be applied to any scenario requiring reactive power compensation and harmonic compensation of the power grid. Specifically, when a user needs to perform reactive power compensation and harmonic compensation on the power grid, the various steps of the power grid compensation method provided in this application can be executed through compensation equipment, thereby achieving simultaneous reactive power compensation and harmonic compensation of the power grid, ultimately improving the effect of power grid compensation.

[0027] Please see Figure 1 , Figure 1 The flowchart illustrates the implementation of the power grid compensation method provided in this application embodiment. The power grid compensation method provided in this application embodiment may include S101~S105, as detailed below: In S101, the sampled voltage and sampled current of the power grid are obtained.

[0028] In this embodiment of the application, the compensation device first needs to sample and filter the two analog quantities of the grid voltage and current, so as to obtain the sampled voltage and sampled current of the grid.

[0029] In S102, the fundamental positive sequence phase of the power grid is determined based on the sampled voltage.

[0030] In this embodiment of the application, after obtaining the sampling voltage and sampling current of the power grid, the compensation device can determine the fundamental positive sequence phase of the power grid based on the sampling voltage.

[0031] In practical applications, the accuracy of determining the fundamental positive sequence phase of the power grid is mainly limited by the performance of the phase-locked loop (PLL). If there is an imbalance in the grid voltage, using a regular PLL will not be able to accurately determine the fundamental positive sequence phase of the grid, which will lead to inaccurate compensation current commands and may ultimately inject reactive power and harmonic power into the grid.

[0032] To address the above issues, the compensation equipment can determine the fundamental positive-sequence phase of the power grid based on the sampled voltage using the following method: The compensation device can determine the positive-sequence component of the fundamental voltage of the power grid based on the sampled voltage through a positive-negative sequence separation phase-locked loop, and perform phase-locking processing on the positive-sequence component of the fundamental voltage through the positive-negative sequence separation phase-locked loop, and determine the positive-sequence phase of the fundamental voltage based on the positive-sequence component of the fundamental voltage after phase-locking processing.

[0033] The specific method for a positive-sequence separation phase-locked loop to determine the positive-sequence component of the fundamental voltage of the power grid based on the sampled voltage can be as follows: The fundamental voltage signal is phase-shifted by using an all-pass filter based on the fundamental rated frequency of the fundamental voltage signal corresponding to the sampled voltage; the interference of high-frequency harmonics on the phase-shifted fundamental voltage signal is filtered out by a low-pass filter to obtain the target fundamental signal; and the positive sequence component of the fundamental voltage is determined based on the target fundamental signal.

[0034] For example, an all-pass filter can be used. ,in At the fundamental frequency, the full-band amplitude gain of this filter is 0dB. This all-pass filter can produce a 90° phase lag for the fundamental voltage signal at the fundamental frequency, thereby achieving the purpose of phase shifting the fundamental voltage signal.

[0035] The following explains why phase shift processing of the fundamental voltage signal is necessary: According to the symmetrical component method, in a two-phase stationary coordinate system, the grid voltage... and orthogonal components The following relationships exist:

[0036] in This indicates a phase shift of 90°. It can be seen that in the process of separating the positive-sequence component and the negative-sequence component of the fundamental voltage, the phase of the fundamental voltage signal needs to be shifted by 90° in the α-β coordinate system.

[0037] In S103, the corresponding compensation current command of the power grid is determined based on the fundamental positive sequence phase and the sampled current.

[0038] In this embodiment of the application, after determining the fundamental positive sequence phase of the power grid, the corresponding compensation current command of the power grid can be determined based on the fundamental positive sequence phase and the sampled current.

[0039] The following combination Figure 2 This paper provides a detailed explanation of the specific implementation method for determining the corresponding compensation current command of the power grid based on the fundamental positive sequence phase and the sampled current. Figure 2 This is a schematic diagram of a method for determining the compensation current command corresponding to the power grid, provided in an embodiment of this application.

[0040] Please see Figure 2 ,exist Figure 2 In this context, a PLL can be represented as a positive-to-negative sequence phase-locked loop. It can be represented as the sampling voltage, and sin and cos represent the fundamental positive sequence phase of the power grid.

[0041] First, the compensation device can perform coordinate transformation on the first three-phase current corresponding to the sampled current based on the fundamental positive sequence phase to obtain the dq-axis current of the sampled current in the synchronous rotating coordinate system.

[0042] Please see Figure 2 ,exist Figure 2 middle, , as well as Together, they represent the first three-phase currents corresponding to the sampled current. This can be expressed as "performing coordinate transformation on the first three-phase current corresponding to the sampled current". Specifically, the first three-phase current corresponding to the sampled current can be transformed from the abc axis to the dq axis (the axis in the synchronous rotating coordinate system) to obtain the dq axis current of the sampled current in the synchronous rotating coordinate system.

[0043] Afterwards, the compensation device can filter the dq-axis current using a low-pass filter to determine the DC component of the dq-axis.

[0044] Please see Figure 2 ,exist Figure 2 In this context, LPF stands for low-pass filter. and These represent the DC components of the d-axis and q-axis, respectively.

[0045] Afterwards, the compensation device can perform coordinate inverse transformation on the DC component of the dq axis according to the fundamental positive sequence phase to obtain the second and third phase currents.

[0046] Please see Figure 2 ,exist Figure 2 middle, This is expressed as "performing an inverse coordinate transformation on the DC component of the dq axis." Specifically, the DC component of the dq axis can be transformed from the dq axis to the abc axis to obtain the second and third phase currents. Figure 2 middle, , as well as Together they are represented as the second and third phase currents.

[0047] Finally, the compensation device can be based on the first three-phase current ( , as well as ) and second and third phase currents ( , as well as ), determine the compensation current command.

[0048] Specifically, the compensation device determines the compensation current command based on the first three-phase current and the second three-phase current in the following ways: determine the first a-phase current, the first b-phase current, and the first c-phase current corresponding to the first three-phase current; determine the second a-phase current, the second b-phase current, and the second c-phase current corresponding to the second three-phase current; determine the a-phase current difference based on the first a-phase current and the second a-phase current; determine the b-phase current difference based on the first b-phase current and the second b-phase current; determine the c-phase current difference based on the first c-phase current and the second c-phase current; and determine the compensation current command based on the a-phase current difference, the b-phase current difference, and the c-phase current difference.

[0049] Among them, the first a-phase current, the first b-phase current, and the first c-phase current corresponding to the first three-phase current can be respectively , as well as The second phase current, second phase current, and second phase current corresponding to the second and third phase currents can be respectively... , as well as .

[0050] Wherein, the current difference of phase a can be expressed as * The phase a current difference can specifically be the difference between the first phase a current and the second phase a current; that is, determining the phase a current difference... The formula for * can be: *= -

[0051] Wherein, the current difference in phase b can be expressed as * The phase b current difference can specifically be the difference between the first phase b current and the second phase b current; that is, determining the phase b current difference... The formula for * can be: *= -

[0052] Wherein, the current difference of phase c can be expressed as * The c-phase current difference can specifically be the difference between the first c-phase current and the second c-phase current; that is, determining the c-phase current difference... The formula for * can be: *= -

[0053] The compensation current command can be used to simultaneously compensate the power grid for reactive power and harmonics. The specific method for determining the compensation current command based on the current differences in phases a, b, and c can be set according to actual needs and is not limited here.

[0054] It should be noted that, in order to determine the compensation current command used for simultaneously performing reactive power compensation and harmonic compensation on the power grid, in Figure 2 Switch S in the circuit needs to be turned off.

[0055] In S104, the reference value of the compensation current is determined according to the compensation current command.

[0056] In this embodiment, after determining the compensation current command, a compensation current reference value can be determined based on the compensation current command. Specifically, the compensation device can first obtain a composite compensation controller. The composite compensation controller may include a repetitive compensation controller and a proportional-integral compensation controller.

[0057] Specifically, the method for obtaining a composite compensation controller for the compensation device can be as follows: obtain an initial repetitive compensation controller; the integral processing method of the initial repetitive compensation controller is ideal integration; modify the integral processing method of the initial repetitive compensation controller to quasi-integral processing to obtain a target repetitive compensation controller; combine the target repetitive compensation controller with a proportional-integral compensation controller to obtain a composite compensation controller.

[0058] For example, the initial repetition compensation controller can be represented by the following formula:

[0059] Where N = Ts / T, Ts is the sampling period, and T is the fundamental frequency period. Let R(z) be the transfer function of the initial repetitive compensation controller in the discrete domain (z-domain), describing the input-output relationship of the initial repetitive compensation controller. R(z) represents the output signal of the initial repetitive compensation controller (in z-domain), that is, the control signal output after initial repetitive control adjustment. E(z) represents the input error signal of the initial repetitive compensation controller (in z-domain). It is represented as a delay operator in the discrete domain, and its core function is to achieve periodic delay of the signal.

[0060] As can be seen from the formula, the initial integral processing method of the repetitive compensation controller is ideal integral. In order to improve the stability of the repetitive compensation controller, the ideal integral needs to be transformed into a quasi-integral to obtain the target repetitive compensation controller.

[0061] For example, the target repetition compensation controller can be represented by the following formula:

[0062] Where N = Ts / T, Ts is the sampling period, and T is the fundamental frequency period. Let R(z) be the transfer function of the target repetitive compensation controller in the discrete domain (z-domain), describing the input-output relationship of the target repetitive compensation controller. R(z) represents the output signal of the target repetitive compensation controller (in z-domain), that is, the control signal output after the target repetitive control adjustment. E(z) represents the input error signal of the target repetitive compensation controller (in z-domain). It is represented as a delay operator in the discrete domain. Its core function is to realize the periodic delay of the signal. Q(z) represents the stability correction parameter of the target repetition compensation controller. It can be a constant slightly less than 1 or designed as a low-pass filter.

[0063] This formula shows that the integral processing method of the target repetitive compensation controller is quasi-integral processing.

[0064] Compared with the initial repetitive compensation controller, the improved target repetitive compensation controller has higher stability. However, the steady-state accuracy of the target repetitive compensation controller is reduced. In addition, the repetitive control has good steady-state tracking accuracy, but since the internal mode of the repetitive control adjusts the output control quantity by accumulating the error signal with the fundamental period of the signal as the step size, the target repetitive compensation controller has the defect of slow dynamic response time, which is usually greater than one fundamental period.

[0065] Because proportional-integral (PI) compensation controllers have the advantage of fast dynamic response, and considering the shortcomings of target repetitive compensation controllers, they can be combined to obtain a composite compensation controller. This composite compensation controller combines the high stability of the target repetitive compensation controller with the fast dynamic response of the PI compensation controller, thereby improving the performance of the obtained composite compensation controller. This, in turn, improves the accuracy and efficiency of determining the compensation current reference value, and ultimately enhances the effect of power grid compensation.

[0066] For example, a schematic diagram of the composite compensation controller can be found in [reference needed]. Figure 3 , Figure 3 This is a schematic diagram of a composite compensation controller provided in an embodiment of this application.

[0067] exist Figure 3 In this diagram, G(z) represents the controlled object, and C(z) represents the target repetitive compensation controller. The function of the target repetitive compensation controller C(z) is to compensate for the amplitude and phase of the object to meet the stability requirements of the composite compensation controller. The expression for the target repetitive compensation controller can be as follows:

[0068] Where Kr is the gain of the repetitive controller. To compensate for the phase lag of the controlled object at high frequencies, S(z) is a low-pass filter. A second-order Buster-Warf filter can be used to ensure the attenuation and stability of the composite compensation controller at high frequencies.

[0069] exist Figure 3 In the context of the target repetitive controller, the equivalent controlled object P(z) is a proportional-integral controller. For a closed-loop system consisting of the controlled object G(z), the equivalent control object P(z) is expressed as:

[0070] Where Gpi(z) is the z-domain transfer function of the proportional-integral controller, and G(z) is the transfer function of the controlled object in the Z-domain.

[0071] When the output of the composite compensation controller is an inductor filter, the expression for the controlled object G(z) in the frequency domain, G(s), is:

[0072] Substituting G(s) into the circuit parameters and discretizing using zero-order hold, we can obtain the transfer function G(z) of the controlled object in the Z-domain, and finally the closed-loop transfer function of the entire composite compensation controller. It can be as follows:

[0073] Where C(z) represents the target repetitive compensation controller, For the equivalent controlled object, Q(z) represents the stability correction parameter of the target repetitive compensation controller.

[0074] After obtaining the composite compensation controller, the compensation equipment can determine the compensation current reference value based on the compensation current command and the corresponding control command of the outer loop compensation controller. Specifically, the compensation current command and the corresponding control command of the outer loop compensation controller can be input into the composite compensation controller to instruct it to determine and output the compensation current reference value.

[0075] In S105, reactive power compensation and harmonic compensation are performed on the power grid based on the compensation current reference value.

[0076] In this embodiment of the application, after determining the compensation current reference value, the compensation current reference value can be subjected to coordinate transformation processing. Specifically, the compensation current reference value located in the dq coordinate system can be transformed to the three-phase stationary coordinate system (i.e., the abc coordinate system) to obtain the compensation current reference value after coordinate transformation processing.

[0077] Afterwards, the coordinates of the decoupled compensation current reference value can be transformed back to the three-phase stationary coordinate system to obtain the reference modulation wave, which is then modulated by a sinusoidal pulse width modulation to obtain a pulse signal, which controls the conduction and cutoff of the power electronic switch tube, thereby enabling the corresponding equipment to output compensation current.

[0078] As can be seen from the above, in the power grid compensation method provided in this application embodiment, the sampled voltage and sampled current of the power grid are first obtained. Then, based on the sampled voltage, the fundamental positive sequence phase of the power grid is determined. Based on the fundamental positive sequence phase and the sampled current, the corresponding compensation current command for the power grid is determined. Then, based on the compensation current command, a compensation current reference value is determined. Finally, based on the compensation current reference value, reactive power compensation and harmonic compensation are performed on the power grid. The power grid compensation method provided in this application can simultaneously perform reactive power compensation and harmonic compensation on the power grid, solving the technical problem in the prior art that it is impossible to simultaneously perform reactive power compensation and harmonic compensation on the power grid, and improving the effect of power grid compensation.

[0079] Furthermore, in the power grid compensation method provided in this application embodiment, the compensation current reference value is determined by a composite compensation controller including a target repetitive compensation controller and a proportional-integral compensation controller. Since the target repetitive compensation controller has higher stability and the proportional-integral compensation controller has the advantage of fast dynamic response speed, the composite compensation controller has the advantages of both the high stability of the target repetitive compensation controller and the fast dynamic response speed of the proportional-integral compensation controller. This improves the performance of the obtained composite compensation controller, thereby improving the accuracy and efficiency of determining the compensation current reference value, and ultimately improving the effect of power grid compensation.

[0080] Based on the power grid compensation method provided in the above embodiments, this application further provides a power grid compensation device for implementing the above method embodiments. Please refer to [link to relevant documentation]. Figure 4 , Figure 4 This is a schematic diagram of the structure of a power grid compensation device provided in an embodiment of this application. Figure 4 As shown, the power grid compensation device 40 may include: an acquisition unit 41, a first determination unit 42, a second determination unit 43, a third determination unit 44, and a compensation unit 45. Wherein: The acquisition unit 41 is used to acquire the sampled voltage and sampled current of the power grid.

[0081] The first determining unit 42 is used to determine the fundamental positive sequence phase of the power grid based on the sampled voltage.

[0082] The second determining unit 43 is used to determine the corresponding compensation current command of the power grid based on the fundamental positive sequence phase and the sampled current.

[0083] The third determining unit 44 is used to determine the compensation current reference value according to the compensation current command.

[0084] The compensation unit 45 is used to perform reactive power compensation and harmonic compensation on the power grid based on the compensation current reference value.

[0085] Optionally, the first determining unit 42 is specifically used for: The positive-sequence component of the fundamental voltage of the power grid is determined by the positive-sequence separation phase-locked loop based on the sampled voltage. The positive-sequence component of the fundamental voltage is then phase-locked through the positive-sequence separation phase-locked loop, and the positive-sequence phase of the fundamental voltage is determined based on the phase-locked positive-sequence component of the fundamental voltage.

[0086] Optionally, the first determining unit 42 is specifically used for: The fundamental voltage signal is phase-shifted by using an all-pass filter based on the fundamental rated frequency of the fundamental voltage signal corresponding to the sampled voltage. The target fundamental signal is obtained by filtering out the interference of high-frequency harmonics on the phase-shifted fundamental voltage signal through a low-pass filter. Based on the target fundamental signal, determine the positive sequence component of the fundamental voltage.

[0087] Optionally, the second determining unit 43 is specifically used for: Based on the fundamental positive sequence phase, the first three-phase current corresponding to the sampling current is subjected to coordinate transformation to obtain the dq axis current of the sampling current in the synchronous rotating coordinate system. The dq-axis current is filtered by a low-pass filter to determine the DC component of the dq-axis. Based on the fundamental positive sequence phase, the DC component of the dq axis is subjected to inverse coordinate transformation to obtain the second and third phase currents; The compensation current command is determined based on the first and third phase currents and the second and third phase currents.

[0088] Optionally, the second determining unit 43 is specifically used for: Determine the first a-phase current, the first b-phase current, and the first c-phase current corresponding to the first three-phase current; Determine the second a-phase current, the second b-phase current, and the second c-phase current corresponding to the second three-phase current; The phase a current difference is determined based on the first phase a current and the second phase a current. The phase b current difference is determined based on the first phase b current and the second phase b current. The difference between phase c currents is determined based on the first phase c current and the second phase c current. The compensation current command is determined based on the current difference between phase a, phase b, and phase c.

[0089] Optionally, the third determining unit 44 is specifically used for: Obtain the composite compensation controller; The composite compensation controller determines the reference value of the compensation current based on the compensation current command and the corresponding control command of the outer loop compensation controller.

[0090] Optionally, the third determining unit 44 is specifically used for: Obtain the initial repetitive compensation controller; the integral processing method of the initial repetitive compensation controller is ideal integral; The integral processing method of the initial repetitive compensation controller is modified to quasi-integral processing to obtain the target repetitive compensation controller; By combining the target repetitive compensation controller with the proportional-integral compensation controller, a composite compensation controller is obtained.

[0091] It should be noted that the information interaction and execution process between the above-mentioned units are based on the same concept as the method embodiments of this application. Their specific functions and technical effects can be referred to the method embodiments section, and will not be repeated here.

[0092] Please see Figure 5 , Figure 5 This is a schematic diagram of a compensation device provided in an embodiment of this application. Figure 5 As shown, the compensation device 5 provided in this embodiment may include: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50, such as a program corresponding to a power grid compensation method. When the processor 50 executes the computer program 52, it implements the steps described in the embodiment of the compensation method applied to the power grid, for example... Figure 1 S101~S105 are shown. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module / unit in the above-described power grid compensation device embodiment, for example... Figure 4 The functions of units 41-45 shown.

[0093] For example, the computer program 52 can be divided into one or more modules / units, one or more of which are stored in the memory 51 and executed by the processor 50 to complete this application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 52 in the compensation device 5. For example, the computer program 52 can be divided into an acquisition unit 41, a first determining unit 42, a second determining unit 43, a third determining unit 44, and a compensation unit 45. For the specific functions of each unit, please refer to [link to relevant documentation]. Figure 4 The relevant descriptions in the corresponding embodiments are not repeated here.

[0094] Those skilled in the art will understand that Figure 5This is merely an example of compensation device 5 and does not constitute a limitation on compensation device 5. It may include more or fewer components than shown, or combine certain components, or use different components.

[0095] The processor 50 can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0096] The memory 51 can be an internal storage unit of the compensation device 5, such as a hard disk or RAM of the compensation device 5. The memory 51 can also be an external storage device of the compensation device 5, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, or flash card equipped on the compensation device 5. Furthermore, the memory 51 can include both internal and external storage units of the compensation device 5. The memory 51 is used to store computer programs and other programs and data required by the compensation device. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0097] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units is merely an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the power grid compensation device can be divided into different functional units to complete all or part of the functions described above. The functional units in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0098] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the steps in the various method embodiments described above.

[0099] This application provides a computer program product that, when run on a terminal device, enables the terminal device to implement the steps described in the various method embodiments above.

[0100] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, refer to the relevant descriptions of other embodiments.

[0101] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A power grid compensation method, characterized in that, include: Obtain the sampled voltage and sampled current of the power grid; The fundamental positive sequence phase of the power grid is determined based on the sampled voltage. Based on the fundamental positive sequence phase and the sampled current, the corresponding compensation current command for the power grid is determined; Determine the reference value of the compensation current according to the compensation current command; Based on the aforementioned compensation current reference value, reactive power compensation and harmonic compensation are performed on the power grid.

2. The method according to claim 1, characterized in that, Determining the fundamental positive sequence phase of the power grid based on the sampled voltage includes: The positive-sequence component of the fundamental voltage of the power grid is determined by the positive-sequence separation phase-locked loop based on the sampled voltage, and the positive-sequence component of the fundamental voltage is phase-locked by the positive-sequence separation phase-locked loop. The fundamental positive-sequence phase is determined based on the phase-locked positive-sequence component of the fundamental voltage.

3. The method according to claim 2, characterized in that, Determining the fundamental positive-sequence component of the power grid based on the sampled voltage includes: The fundamental voltage signal is phase-shifted by an all-pass filter based on the fundamental rated frequency of the fundamental voltage signal corresponding to the sampling voltage. The target fundamental signal is obtained by filtering out the interference of high-frequency harmonics on the phase-shifted fundamental voltage signal through a low-pass filter. Based on the target fundamental signal, determine the positive sequence component of the fundamental voltage.

4. The method according to claim 1, characterized in that, The step of determining the compensation current command corresponding to the power grid based on the fundamental positive sequence phase and the sampled current includes: Based on the fundamental positive sequence phase, the first three-phase current corresponding to the sampling current is subjected to coordinate transformation to obtain the dq-axis current of the sampling current in the synchronous rotating coordinate system. The dq-axis current is filtered using a low-pass filter to determine the DC component of the dq-axis. Based on the fundamental positive sequence phase, the DC component of the dq axis is subjected to inverse coordinate transformation to obtain the second three-phase current; The compensation current command is determined based on the first three-phase current and the second three-phase current.

5. The method according to claim 4, characterized in that, The step of determining the compensation current command based on the first three-phase current and the second three-phase current includes: Determine the first a-phase current, the first b-phase current, and the first c-phase current corresponding to the first three-phase current; Determine the second a-phase current, the second b-phase current, and the second c-phase current corresponding to the second and third phase currents; The phase a current difference is determined based on the first phase a current and the second phase a current; The phase b current difference is determined based on the first phase b current and the second phase b current; The c-phase current difference is determined based on the first c-phase current and the second c-phase current; The compensation current command is determined based on the current difference of phase a, the current difference of phase b, and the current difference of phase c.

6. The method according to any one of claims 1 to 5, characterized in that, Determining the compensation current reference value according to the compensation current command includes: Obtain the composite compensation controller; The composite compensation controller determines the reference value of the compensation current based on the compensation current command and the control command corresponding to the outer loop compensation controller.

7. The method according to claim 6, characterized in that, The acquisition of the composite compensation controller includes: Obtain the initial repetitive compensation controller; the integration processing method of the initial repetitive compensation controller is ideal integration; The integral processing method of the initial repetitive compensation controller is modified to quasi-integral processing to obtain the target repetitive compensation controller; The composite compensation controller is obtained by combining the target repetitive compensation controller with the proportional-integral compensation controller.

8. A power grid compensation device, characterized in that, include: The acquisition unit is used to acquire the sampled voltage and sampled current of the power grid; The first determining unit is used to determine the fundamental positive sequence phase of the power grid based on the sampled voltage. The second determining unit is used to determine the compensation current command corresponding to the power grid based on the fundamental positive sequence phase and the sampled current. The third determining unit is used to determine the compensation current reference value according to the compensation current command; The compensation unit is used to perform reactive power compensation and harmonic compensation on the power grid based on the compensation current reference value.

9. A compensation device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements each step of the power grid compensation method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, When the computer program product is executed by a processor, it implements the steps of the power grid compensation method as described in any one of claims 1 to 7.

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