Frequency response distortion compensation method and device based on black box inverse model

Abstract

The invention discloses a frequency response distortion compensation method and device based on a black box inverse model, and belongs to the technical field of voltage transformers, and the method comprises the steps: collecting the actual load impedance and the real-time secondary side voltage in real time when the secondary side voltage waveform frequency response distortion of a voltage transformer is detected; acquiring initial load impedance, generalized short-circuit impedance and auxiliary impedance; calculating a real-time primary side voltage based on the real-time secondary side voltage by using a voltage transmission unit of a black box inverse model; calculating a load current change difference value, and calculating a compensation voltage of the voltage transformer based on the load current change difference value by using a generalized short-circuit impedance unit of the black-box inverse model; and correcting the real-time primary side voltage based on the calculated compensation voltage so as to obtain the compensated primary side voltage of the voltage transformer, and performing primary side voltage compensation control on the voltage transformer based on the compensated primary side voltage. Therefore, by implementing the method and the device, the problem of poor frequency response distortion compensation effect in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of voltage transformer technology, and in particular to a frequency response distortion compensation method and apparatus based on a black-box inverse model. Background Technology

[0002] The voltage transfer characteristics of a voltage transformer are jointly determined by its generalized short-circuit impedance and external parameters (transformer load impedance). Existing methods for compensating for frequency response distortion of secondary voltage waveforms cannot characterize the wideband transfer characteristics of the internal electrical quantities (generalized short-circuit impedance) of the voltage transformer. Therefore, existing compensation methods only consider the actual load impedance. When the inverse function of the voltage transfer characteristic used in the compensation method does not match the actual load impedance of the voltage transformer, the accuracy of the calculated voltage will drop significantly, and the harmonic measurement error can reach 39%, far exceeding the allowable error range of harmonic measurement in the specification, resulting in poor frequency response distortion compensation. Summary of the Invention

[0003] This invention provides a frequency response distortion compensation method and apparatus based on a black-box inverse model, which can solve the problem of poor frequency response distortion compensation effect in the prior art.

[0004] To address the aforementioned technical problems, this invention provides a frequency response distortion compensation method based on a black-box inverse model, comprising:

[0005] When frequency response distortion of the secondary voltage waveform of the voltage transformer is detected, the actual load impedance and real-time secondary voltage of the voltage transformer are collected in real time.

[0006] The initial load impedance, generalized short-circuit impedance, and auxiliary impedance of the voltage transformer are obtained respectively.

[0007] Using the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance.

[0008] Based on the actual load impedance, the real-time secondary voltage, and the initial load impedance, calculate the load current variation difference of the voltage transformer;

[0009] Using the generalized short-circuit impedance unit of the black-box inverse model, the compensation voltage of the voltage transformer is calculated based on the load current variation difference and the generalized short-circuit impedance.

[0010] Based on the compensation voltage, the real-time primary voltage is corrected to obtain the compensated primary voltage of the voltage transformer;

[0011] The voltage transformer is subjected to primary side voltage compensation control based on the compensated primary side voltage.

[0012] As a preferred approach, the generalized short-circuit impedance is determined as follows:

[0013] The secondary winding of the voltage transformer is controlled to be in a short-circuit state.

[0014] Obtain the transformer ratio of the voltage transformer;

[0015] The primary side voltage and secondary side short-circuit current of the voltage transformer are detected when the secondary winding is short-circuited.

[0016] The generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current.

[0017] As a preferred embodiment, the calculation of the generalized short-circuit impedance based on the transformer ratio, the primary voltage, and the secondary short-circuit current includes:

[0018] The generalized short-circuit impedance is calculated using the following formula:

[0019]

[0020] In the formula, Z G U1 is the generalized short-circuit impedance; U2 is the primary side voltage; I2 is the secondary side short-circuit current; k v For the transformer ratio.

[0021] As a preferred approach, the auxiliary impedance is determined in the following manner:

[0022] The secondary winding of the voltage transformer is controlled to be in an open-circuit state.

[0023] The no-load voltage transfer characteristic value of the voltage transformer under the open-circuit condition of the secondary winding is detected;

[0024] The auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value.

[0025] As a preferred embodiment, the calculation of the auxiliary impedance based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value includes:

[0026] The auxiliary impedance is calculated using the following formula:

[0027]

[0028] In the formula, Z H For auxiliary impedance; Z G H is the generalized short-circuit impedance; linear_0 This represents the no-load voltage transmission characteristic value.

[0029] As a preferred embodiment, the voltage transmission unit utilizing the black-box inverse model calculates the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance, including:

[0030] Based on the voltage correlation formula between the primary and secondary voltages in the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated using the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance.

[0031] The voltage correlation formula is as follows:

[0032]

[0033] In the formula, V pZL1 This is the real-time primary side voltage; V sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L1 This is the initial load impedance.

[0034] As a preferred embodiment, the calculation of the load current variation difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage, and the initial load impedance includes:

[0035] Obtain the load current correlation formula between the load current variation difference and the actual load impedance;

[0036] Based on the load current correlation formula, the load current variation difference of the voltage transformer is calculated using the actual load impedance, the real-time secondary voltage, and the initial load impedance.

[0037] The load current correlation formula is as follows:

[0038]

[0039] In the formula, i s12 V represents the difference in load current variation. sh This refers to the real-time secondary side voltage; Z L Z represents the actual load impedance. L1 This is the initial load impedance.

[0040] As a preferred embodiment, the calculation of the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance using the generalized short-circuit impedance of the black-box inverse model includes:

[0041] The compensation voltage calculation formula is obtained from the generalized short-circuit impedance unit of the black box inverse model;

[0042] Based on the compensation voltage calculation formula, the compensation voltage of the voltage transformer is calculated using the load current variation difference and the generalized short-circuit impedance.

[0043] The formula for calculating the compensation voltage is as follows:

[0044] V pZG =Z G ·i s12

[0045] In the formula, V pZG For voltage compensation; i s12 Z represents the difference in load current variation. G This is the generalized short-circuit impedance.

[0046] As a preferred embodiment, the step of compensating the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer includes:

[0047] The primary voltage of the voltage transformer after compensation is calculated using the following formula:

[0048] V ph =V pZL1 +V pZG

[0049] In the formula, V ph To compensate for the primary side voltage; V pZL1 This is the real-time primary side voltage; V pZG To compensate for the voltage.

[0050] Accordingly, the present invention provides a frequency response distortion compensation device based on a black box inverse model, comprising: a data acquisition module, a data acquisition module, a primary voltage calculation module, a current difference calculation module, a compensation voltage calculation module, a voltage correction module, and a voltage compensation module;

[0051] The data acquisition module is used to acquire the actual load impedance and real-time secondary voltage of the voltage transformer in real time when frequency response distortion of the secondary voltage waveform of the voltage transformer is detected.

[0052] The data acquisition module is used to acquire the initial load impedance, generalized short-circuit impedance and auxiliary impedance of the voltage transformer, respectively.

[0053] The primary voltage calculation module is used to calculate the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance using the voltage transmission unit of the black-box inverse model.

[0054] The current difference calculation module is used to calculate the load current change difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage and the initial load impedance;

[0055] The compensation voltage calculation module is used to calculate the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance using the generalized short-circuit impedance unit of the black-box inverse model.

[0056] The voltage correction module is used to correct the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer.

[0057] The voltage compensation module is used to perform primary-side voltage compensation control on the voltage transformer based on the compensated primary-side voltage.

[0058] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0059] This invention provides a frequency response distortion compensation method based on a black-box inverse model. When frequency response distortion of the secondary voltage waveform of a voltage transformer is detected, the actual load impedance and real-time secondary voltage of the voltage transformer are acquired in real time, along with the initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On one hand, using the voltage transmission unit of the black-box inverse model, the real-time primary voltage is calculated based on the real-time secondary voltage, initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On the other hand, the load current variation difference is calculated, and using the generalized short-circuit impedance unit of the black-box inverse model, the compensation voltage of the voltage transformer is calculated based on the load current variation difference and the generalized short-circuit impedance. The real-time primary voltage is corrected based on the calculated compensation voltage, thus obtaining the compensated primary voltage of the voltage transformer. The primary voltage compensation control of the voltage transformer is then performed based on the compensated primary voltage. This invention performs frequency response distortion compensation analysis based on a black-box inverse model with embedded generalized short-circuit impedance, considering the voltage transmission characteristic of the voltage transformer, which effectively improves the accuracy of the compensation voltage and thus enhances the effect of frequency response distortion compensation. Attached Figure Description

[0060] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments 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 from these drawings without creative effort.

[0061] Figure 1 This is a flowchart illustrating an embodiment of the frequency response distortion compensation method based on the black-box inverse model provided by the present invention.

[0062] Figure 2 A schematic diagram of a black-box positive model provided by the present invention;

[0063] Figure 3 This is a flowchart illustrating another embodiment of the frequency response distortion compensation method based on the black-box inverse model provided by the present invention.

[0064] Figure 4 This is a schematic diagram of an embodiment of the frequency response distortion compensation device based on the black-box inverse model provided by the present invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0067] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0068] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0069] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0070] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0071] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0072] Example 1

[0073] See Figure 1 To address the poor frequency response distortion compensation effect in existing technologies, an embodiment of the present invention provides a frequency response distortion compensation method based on a black-box inverse model. This method includes steps 101 to 107, each step of which is detailed below:

[0074] Step 101: When frequency response distortion of the secondary voltage waveform of the voltage transformer is detected, the actual load impedance and real-time secondary voltage of the voltage transformer are collected in real time.

[0075] In this embodiment of the invention, voltage transformers have varying transmission capabilities for signals of different frequencies. Therefore, voltage transformers may experience frequency response distortion during operation. By monitoring the secondary voltage waveform of the voltage transformer in real time, it is possible to determine whether frequency response distortion is currently occurring by observing its waveform characteristics. When frequency response distortion is determined to have occurred based on the secondary voltage waveform, the actual load impedance and real-time secondary voltage of the voltage transformer are collected in real time. The actual load impedance of the voltage transformer refers to the equivalent impedance of all loads connected to its secondary side (such as instruments, relays, connecting wires, etc.), which directly affects the error characteristics and operational safety of the voltage transformer. Therefore, voltage compensation analysis based on the actual load impedance of the voltage transformer can improve the accuracy of compensation voltage calculation.

[0076] Step 102: Obtain the initial load impedance, generalized short-circuit impedance and auxiliary impedance of the voltage transformer respectively.

[0077] In this embodiment of the invention, the generalized short-circuit impedance, auxiliary impedance, and transformer load impedance can jointly characterize the voltage transmission characteristics of a voltage transformer dominated by frequency characteristics. The generalized short-circuit impedance is the equivalent impedance presented on the primary side of the voltage transformer when the secondary side is short-circuited, reflecting the combined effect of internal losses and electromagnetic characteristics. The auxiliary impedance is an additional impedance artificially added inside the voltage transformer to improve performance (such as suppressing ferroresonance and compensating for errors), usually connected in series or parallel in the primary or secondary circuit. The transformer load impedance is the equivalent impedance of the load actually connected to the secondary side of the voltage transformer, including the sum of the impedances of measuring instruments, protection devices, connecting wires, and other components, directly determining the magnitude of the secondary current and the operating state of the transformer. Therefore, when a voltage transformer exhibits frequency response distortion, obtaining the initial load impedance, generalized short-circuit impedance, and auxiliary impedance of the voltage transformer can determine the voltage transmission characteristics, thereby enabling accurate analysis of the compensation voltage.

[0078] As a preferred embodiment, the generalized short-circuit impedance is determined in the following manner:

[0079] The secondary winding of the voltage transformer is controlled to be in a short-circuit state.

[0080] Obtain the transformer ratio of the voltage transformer;

[0081] The primary side voltage and secondary side short-circuit current of the voltage transformer are detected when the secondary winding is short-circuited.

[0082] The generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current.

[0083] In this embodiment of the invention, when the secondary winding of the voltage transformer is short-circuited, the load impedance of the transformer is zero, and the auxiliary impedance is also short-circuited. The impedance between the primary voltage and the secondary short-circuit current at this time is the generalized short-circuit impedance. Specifically, the secondary winding of the voltage transformer is first controlled to be in a short-circuit state. Then, the primary voltage and secondary short-circuit current of the voltage transformer under this short-circuit state are detected, and the generalized short-circuit impedance is calculated based on the transformer ratio.

[0084] As a preferred embodiment, the generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current, including:

[0085] The generalized short-circuit impedance is calculated using the following formula:

[0086]

[0087] In the formula, Z G U1 is the generalized short-circuit impedance; U2 is the primary side voltage; I2 is the secondary side short-circuit current; k v For the transformer ratio.

[0088] In this embodiment of the invention, for a voltage transformer, the primary and secondary magnetic fields are coupled, and their impedance relationship satisfies the law of electromagnetic induction and the law of energy conservation. The transformer ratio of the voltage transformer is the ratio of the primary voltage to the secondary voltage. The generalized short-circuit impedance refers to the equivalent short-circuit impedance on the primary side, that is, the ratio of the primary voltage to the primary short-circuit current when the secondary side is short-circuited. Since it is difficult to directly measure the primary short-circuit current during actual operation, it needs to be indirectly calculated using secondary parameters. Because the secondary voltage is 0 when the secondary side of the voltage transformer is short-circuited, the secondary short-circuit impedance can be calculated using formula Z. 2SC =U 2OC / I2 is calculated; where Z is... 2SC This is the secondary side short-circuit impedance; U 2OC I0 is the ideal secondary voltage; I2 is the short-circuit current on the secondary side. The ideal secondary voltage U can be calculated using the formula. 2OC =U1 / k v In the formula, U 2OC U1 is the ideal secondary voltage; k is the primary voltage; v Let be the transformer ratio. According to the impedance transformation relationship, the equivalent short-circuit impedance on the primary side is: Therefore, substituting the formula for calculating the secondary short-circuit impedance into the equivalent primary short-circuit impedance described above, we can derive the relationship Z for calculating the generalized short-circuit impedance based on the transformer ratio, primary voltage, and secondary short-circuit current. G =(U1·k v ) / I2. The transformer ratio of the voltage transformer can be determined by the design parameters or nameplate of the voltage transformer.

[0089] As a preferred embodiment, the auxiliary impedance is determined in the following manner:

[0090] The secondary winding of the voltage transformer is controlled to be in an open-circuit state.

[0091] The no-load voltage transfer characteristic value of the voltage transformer under the open-circuit condition of the secondary winding is detected;

[0092] The auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value.

[0093] As a preferred embodiment, the auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value, including:

[0094] The auxiliary impedance is calculated using the following formula:

[0095]

[0096] In the formula, Z H For auxiliary impedance; Z G H is the generalized short-circuit impedance; linear_0 This represents the no-load voltage transmission characteristic value.

[0097] In this embodiment of the invention, when the secondary winding of the voltage transformer is in an open-circuit state (i.e., no-load), the load impedance of the transformer is infinitely large. At this time, the voltage transmission characteristic of the voltage transformer is: H linear_0 =Z H / (Z H +Z G Therefore, based on the no-load voltage transfer characteristics H... linear_0 and generalized short-circuit impedance Z G Calculate the auxiliary impedance Z H Auxiliary impedance Z H It has no physical meaning; it is used to combine the generalized short-circuit impedance Z. G H, which together characterizes the voltage transfer characteristics of a voltage transformer under no-load conditions. linear_0 .

[0098] The following describes the construction process of the black-box inverse model based on the black-box positive model, which can characterize the generalized short-circuit impedance and voltage transfer characteristics of a voltage transformer:

[0099] To compensate for frequency response distortion in the secondary voltage waveform, it is necessary to accurately characterize the generalized short-circuit impedance of the voltage transformer and the inverse function of the voltage transfer characteristic dominated by the frequency characteristics. Therefore, the black-box inverse model is set as follows:

[0100] V pZL1 =H linear_ZL1 -1 V sh (1)

[0101] In the formula, V pZL1 For real-time primary side voltage; H linear_ZL1 -1 V is the inverse function of the voltage transfer characteristic under initial load; sh This is the real-time secondary side voltage.

[0102] See Figure 2 This is a schematic diagram of a black-box positive model provided by the present invention. p V represents the port voltage on the primary side of the black-box positive model in the time domain. s i represents the port voltage on the secondary side of the black-box positive model in the time domain. s This indicates that the actual load impedance Z flows through the current in the time domain. L The current. Z G Z represents the generalized short-circuit impedance.H Z represents the auxiliary impedance. L Representing the actual load impedance, these three factors together characterize the voltage transfer characteristic H of the voltage transformer, which is dominated by frequency characteristics. linear :

[0103]

[0104] In the formula, H linear Voltage transfer characteristics of voltage transformers; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L This represents the actual load impedance.

[0105] The black-box inverse model can be derived from the black-box forward model, where Z... G and Z H Treating them as two independent modules, in characterizing the generalized short-circuit impedance Z G Based on this, by inverting the voltage transfer characteristic formula of the voltage transformer in the above black-box positive model, we can obtain the inverse function of the voltage transfer characteristic of the black-box positive model:

[0106]

[0107] In the formula, H linear -1 Z is the inverse function of the voltage transfer characteristic of a voltage transformer, which is dominated by frequency characteristics; G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L This represents the actual load impedance.

[0108] Let the actual load impedance Z L Equal to the initial load impedance Z L1 By combining equations (1) and (3), the real-time primary voltage V can be obtained. pZL1 With real-time secondary voltage V sh The relationship between them:

[0109]

[0110] In the formula, V pZL1 For real-time primary side voltage; H linear -1 V is the inverse function of the voltage transfer characteristic of a voltage transformer; sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L This represents the actual load impedance.

[0111] When the load impedance of the current transformer is any load impedance Z LAt that time, the secondary voltage V sh The corresponding primary voltage is:

[0112]

[0113] In the formula, V ph The load impedance of the voltage transformer is Z. L The primary voltage at that time; H linear -1 V is the inverse function of the voltage transfer characteristic of a voltage transformer; sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L This represents the actual load impedance.

[0114] Combining equations (4) and (5), we can obtain:

[0115] V ph =V pZL1 +V pZG (6)

[0116] in:

[0117]

[0118] In the formula, V ph The load impedance of the voltage transformer is Z. L The primary voltage at that time; V pZL1 This is the real-time primary side voltage; V pZG V is the voltage on the output side of the generalized short-circuit impedance unit. sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; L Z represents the actual load impedance. L1 This is the initial load impedance.

[0119] From formula (6), it can be seen that when the load impedances of the voltage transformers are Z... L1 and Z L At that time, if the primary side voltage V is different pZL1 and V ph The same secondary voltage V is obtained under the excitation. sh Then V pZL1 and V ph The difference between them is V pZG And V pZG It satisfies the relationship shown in formula (7).

[0120] Therefore, according to formula (7), we can conclude that: ①V pZG Only the difference with load admittance and generalized short-circuit impedance ZG Related; ② Output quantity V pZG With input quantity V sh The relationship between them is a linear function.

[0121] Based on the above analysis, a black-box inverse model including a voltage transfer unit and a generalized short-circuit impedance unit can be constructed. The voltage transfer unit is used to perform the calculation of formula (4) to realize the real-time input secondary voltage V. sh This allows you to obtain the real-time primary side voltage V. pZL1 The generalized short-circuit impedance unit is used to perform the calculation of formula (7) to realize the real-time input secondary voltage V. sh and actual load impedance Z L The compensation voltage can then be obtained.

[0122] Step 103: Using the voltage transmission unit of the black-box inverse model, calculate the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance.

[0123] As a preferred embodiment, the voltage transmission unit of the black-box inverse model calculates the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance, including:

[0124] Based on the voltage correlation formula between the primary and secondary voltages in the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated using the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance.

[0125] The voltage correlation formula is as follows:

[0126]

[0127] In the formula, V pZL1 This is the real-time primary side voltage; V sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L1 This is the initial load impedance.

[0128] In this embodiment of the invention, based on the constructed black-box inverse model, when the voltage transformer exhibits frequency response distortion, the real-time secondary voltage is acquired, along with the initial load impedance, generalized short-circuit impedance, and auxiliary impedance obtained through prior experimental testing. Combined with the voltage correlation formula in the voltage transmission unit, the real-time primary voltage of the voltage transformer can be calculated in real time. Specifically, the voltage transmission unit mainly functions as a simulation of the inverse function of voltage transmission characteristics. First, the vector matching method is used to fit the experimentally measured inverse function of voltage transmission characteristics into a partial fractional form of rational functions. Second, the inverse Laplace transform is used to convert the frequency domain fitting result of the inverse function of voltage transmission characteristics into a continuous state-space equation in the time domain. Finally, the central difference method is used to convert the continuous state-space equation into a discrete state-space equation, and based on this equation, values ​​are assigned to the matrix parameters, and a corresponding inversion calculation program is written to realize the input of the real-time secondary voltage V. sh This allows you to obtain the real-time primary side voltage V. pZL1 .

[0129] Step 104: Calculate the load current variation difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage, and the initial load impedance.

[0130] As a preferred embodiment, the load current variation difference of the voltage transformer is calculated based on the actual load impedance, the real-time secondary voltage, and the initial load impedance, including:

[0131] Obtain the load current correlation formula between the load current variation difference and the actual load impedance;

[0132] Based on the load current correlation formula, the load current variation difference of the voltage transformer is calculated using the actual load impedance, the real-time secondary voltage, and the initial load impedance.

[0133] The load current correlation formula is as follows:

[0134]

[0135] In the formula, i s12 V represents the difference in load current variation. sh This refers to the real-time secondary side voltage; Z L Z represents the actual load impedance. L1 This is the initial load impedance.

[0136] In this embodiment of the invention, the current, voltage, and impedance on the secondary side of the voltage transformer follow Ohm's law, and the current can be calculated by dividing the voltage by the impedance. Therefore, the difference in load current between the initial load impedance and the actual load impedance, combined with Ohm's law, yields the load current correlation formula: The generalized short-circuit impedance element in the black-box inverse model characterizes the real-time secondary voltage V. sh Actual load impedance Z L The relationship between the load current and the compensation voltage. Based on the above load current relationship formula, the relationship in the generalized short-circuit impedance unit can be simplified to V. pZG =Z G ·i s12 Therefore, in order to improve the working efficiency of the black-box inverse model, when the voltage transformer exhibits frequency response distortion, after acquiring the real-time secondary voltage and actual load impedance, and combining it with the pre-measured initial load impedance, the load current variation difference is first calculated, and then the load current variation difference is input to the generalized short-circuit impedance unit so that the generalized short-circuit impedance unit outputs a compensation voltage.

[0137] Step 105: Using the generalized short-circuit impedance unit of the black-box inverse model, calculate the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance.

[0138] As a preferred embodiment, the compensation voltage of the voltage transformer is calculated using the generalized short-circuit impedance unit of the black-box inverse model, based on the load current variation difference and the generalized short-circuit impedance, including:

[0139] The compensation voltage calculation formula is obtained from the generalized short-circuit impedance unit of the black box inverse model;

[0140] Based on the compensation voltage calculation formula, the compensation voltage of the voltage transformer is calculated using the load current variation difference and the generalized short-circuit impedance.

[0141] The formula for calculating the compensation voltage is as follows:

[0142] V pZG =Z G ·i s12

[0143] In the formula, V pZG For voltage compensation; i s12 Z represents the difference in load current variation. G This is the generalized short-circuit impedance.

[0144] In this embodiment of the invention, after obtaining the load current variation difference, the compensation voltage of the voltage transformer can be calculated in real time using the simplified compensation voltage calculation formula in the generalized short-circuit impedance unit, combined with the pre-tested generalized short-circuit impedance. Specifically, the vector matching method should first be used to calculate the Z obtained from the experiment. G The function is fitted into the form of a partial fractional sum of rational functions, and then the inverse Laplace transform is used to transform Z. GThe frequency domain fitting results are converted into continuous state-space equations in the time domain. Finally, the central difference method is used to convert the continuous state-space equations into discrete state-space equations. Based on these equations, values ​​are assigned to the parameters of each matrix, and a corresponding inversion calculation program is written to realize the real-time input secondary side voltage V. sh and actual load impedance Z L The compensation voltage can then be obtained.

[0145] Step 106: Correct the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer.

[0146] As a preferred embodiment, compensation is performed based on the compensation voltage to correct the real-time primary voltage, resulting in the compensated primary voltage of the voltage transformer, including:

[0147] The primary voltage of the voltage transformer after compensation is calculated using the following formula:

[0148] V ph =V pZL1 +V pZG

[0149] In the formula, V ph To compensate for the primary side voltage; V pZL1 This is the real-time primary side voltage; V pZG To compensate for the voltage.

[0150] In this embodiment of the invention, after the compensation voltage is calculated using the black-box inverse model, it is compared with the real-time primary side voltage collected in real time to obtain the compensated primary side voltage. The compensated primary side voltage is the voltage value that the primary side voltage needs to reach after frequency response distortion compensation.

[0151] Step 107: Perform primary side voltage compensation control on the voltage transformer based on the compensated primary side voltage.

[0152] In this embodiment of the invention, after the primary voltage after compensation is determined, the current real-time primary voltage of the voltage transformer is superimposed point-to-point to ensure that the real-time primary voltage of the voltage transformer reaches the voltage value corresponding to the primary voltage after compensation, thereby completing the primary voltage compensation control.

[0153] In this embodiment of the invention, when the actual load impedance Z of the voltage transformer L Equal to the initial load impedance Z L1 At time, or Z L Voltage transfer characteristics H of voltage transformer linearWhen the influence of the generalized short-circuit impedance is minimal, the black-box inverse model with embedded generalized short-circuit impedance only needs to use the voltage transmission unit to compensate for the distortion of the secondary voltage waveform, while the generalized short-circuit impedance unit does not participate in the calculation. In this case, frequency response distortion compensation based on the black-box inverse model can avoid the influence of the generalized short-circuit impedance measurement error on the accuracy of the black-box inverse model, thereby improving the frequency response distortion compensation effect; and since there is no need to use the generalized short-circuit impedance unit for secondary compensation, the computational load of the black-box inverse model is greatly reduced. If the voltage transmission unit and the generalized short-circuit impedance unit have the same order, the computational load can be reduced by up to 50%, which greatly improves the efficiency of frequency response distortion compensation.

[0154] See Figure 3 This is a flowchart illustrating another embodiment of the frequency response distortion compensation method based on a black-box inverse model provided by the present invention. When frequency response distortion occurs in the voltage transformer, the secondary voltage V of the voltage transformer is obtained. sh Based on the secondary side voltage V sh Calculate the difference in load current i s12 The difference in load current i s12 The input is given to the generalized short-circuit impedance unit so that the output compensation voltage V of the generalized short-circuit impedance unit is obtained. pZG On the other hand, the secondary voltage V sh The input is sent to the voltage transmission unit so that the voltage transmission unit outputs the real-time primary side voltage V. pZL1 Finally, combined with the compensation voltage V pZG and real-time primary side voltage V pZL1 The primary voltage V after compensation is obtained through black-box inverse model inversion calculation. ph .

[0155] The black-box inverse model of this invention embeds a generalized short-circuit impedance and includes a generalized short-circuit impedance unit. It successfully introduces a physical coupling mechanism between the load impedance and the generalized short-circuit impedance, breaking through the bottleneck of existing methods that lack the ability to represent the internal electrical quantities of voltage transformers. It realizes the accurate representation of the distortion mechanism of the secondary voltage waveform of voltage transformers and solves the problem of a significant decrease in the frequency response distortion compensation accuracy when the load impedance and the inverse function of voltage transmission characteristics are mismatched.

[0156] Implementing the above embodiments has the following effects:

[0157] This invention provides a frequency response distortion compensation method based on a black-box inverse model. When frequency response distortion of the secondary voltage waveform of a voltage transformer is detected, the actual load impedance and real-time secondary voltage of the voltage transformer are acquired in real time, along with the initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On one hand, using the voltage transmission unit of the black-box inverse model, the real-time primary voltage is calculated based on the real-time secondary voltage, initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On the other hand, the load current variation difference is calculated, and using the generalized short-circuit impedance unit of the black-box inverse model, the compensation voltage of the voltage transformer is calculated based on the load current variation difference and the generalized short-circuit impedance. The real-time primary voltage is corrected based on the calculated compensation voltage, thus obtaining the compensated primary voltage of the voltage transformer. The primary voltage compensation control of the voltage transformer is then performed based on the compensated primary voltage. This invention performs frequency response distortion compensation analysis based on a black-box inverse model with embedded generalized short-circuit impedance, considering the voltage transmission characteristic of the voltage transformer, which effectively improves the accuracy of the compensation voltage and thus enhances the effect of frequency response distortion compensation.

[0158] Example 2

[0159] See Figure 4 This is a schematic diagram of the structure of an embodiment of the frequency response distortion compensation device based on the black box inverse model provided by the present invention. The device includes a data acquisition module, a data acquisition module, a primary voltage calculation module, a current difference calculation module, a compensation voltage calculation module, a voltage correction module, and a voltage compensation module.

[0160] The data acquisition module is used to acquire the actual load impedance and real-time secondary voltage of the voltage transformer in real time when frequency response distortion of the secondary voltage waveform of the voltage transformer is detected.

[0161] The data acquisition module is used to acquire the initial load impedance, generalized short-circuit impedance and auxiliary impedance of the voltage transformer, respectively.

[0162] The primary voltage calculation module is used to calculate the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance using the voltage transmission unit of the black-box inverse model.

[0163] The current difference calculation module is used to calculate the load current change difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage and the initial load impedance;

[0164] The compensation voltage calculation module is used to calculate the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance using the generalized short-circuit impedance unit of the black-box inverse model.

[0165] The voltage correction module is used to correct the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer.

[0166] The voltage compensation module is used to perform primary-side voltage compensation control on the voltage transformer based on the compensated primary-side voltage.

[0167] As a preferred embodiment, the generalized short-circuit impedance is determined by controlling the secondary winding of the voltage transformer to be in a short-circuit state.

[0168] Obtain the transformer ratio of the voltage transformer;

[0169] The primary side voltage and secondary side short-circuit current of the voltage transformer are detected when the secondary winding is short-circuited.

[0170] The generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current.

[0171] As a preferred embodiment, the generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current, including:

[0172] The generalized short-circuit impedance is calculated using the following formula:

[0173]

[0174] In the formula, Z G U1 is the generalized short-circuit impedance; U2 is the primary side voltage; I2 is the secondary side short-circuit current; k v For the transformer ratio.

[0175] As a preferred embodiment, the auxiliary impedance is determined in the following manner:

[0176] The secondary winding of the voltage transformer is controlled to be in an open-circuit state.

[0177] The no-load voltage transfer characteristic value of the voltage transformer under the open-circuit condition of the secondary winding is detected;

[0178] The auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value.

[0179] As a preferred embodiment, the auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value, including:

[0180] The auxiliary impedance is calculated using the following formula:

[0181]

[0182] In the formula, Z H For auxiliary impedance; Z G H is the generalized short-circuit impedance; linear_0 This represents the no-load voltage transmission characteristic value.

[0183] As a preferred embodiment, the voltage transmission unit of the black-box inverse model calculates the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance, including:

[0184] Based on the voltage correlation formula between the primary and secondary voltages in the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated using the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance.

[0185] The voltage correlation formula is as follows:

[0186]

[0187] In the formula, V pZL1 This is the real-time primary side voltage; V sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L1 This is the initial load impedance.

[0188] As a preferred embodiment, the load current variation difference of the voltage transformer is calculated based on the actual load impedance, the real-time secondary voltage, and the initial load impedance, including:

[0189] Obtain the load current correlation formula between the load current variation difference and the actual load impedance;

[0190] Based on the load current correlation formula, the load current variation difference of the voltage transformer is calculated using the actual load impedance, the real-time secondary voltage, and the initial load impedance.

[0191] The load current correlation formula is as follows:

[0192]

[0193] In the formula, i s12 V represents the difference in load current variation. sh This refers to the real-time secondary side voltage; Z L Z represents the actual load impedance. L1 This is the initial load impedance.

[0194] As a preferred embodiment, the compensation voltage of the voltage transformer is calculated using the generalized short-circuit impedance unit of the black-box inverse model, based on the load current variation difference and the generalized short-circuit impedance, including:

[0195] The compensation voltage calculation formula is obtained from the generalized short-circuit impedance unit of the black box inverse model;

[0196] Based on the compensation voltage calculation formula, the compensation voltage of the voltage transformer is calculated using the load current variation difference and the generalized short-circuit impedance.

[0197] The formula for calculating the compensation voltage is as follows:

[0198] V pZG =Z G ·i s12

[0199] In the formula, V pZG For voltage compensation; i s12 Z represents the difference in load current variation. G This is the generalized short-circuit impedance.

[0200] As a preferred embodiment, compensation is performed based on the compensation voltage to correct the real-time primary voltage, resulting in the compensated primary voltage of the voltage transformer, including:

[0201] The primary voltage of the voltage transformer after compensation is calculated using the following formula:

[0202] V ph =V pZL1 +V pZG

[0203] In the formula, V ph To compensate for the primary side voltage; V pZL1 This is the real-time primary side voltage; V pZG To compensate for the voltage.

[0204] Implementing the above embodiments has the following effects:

[0205] This invention provides a frequency response distortion compensation device based on a black-box inverse model. When frequency response distortion of the secondary voltage waveform of a voltage transformer is detected, the device acquires the actual load impedance and real-time secondary voltage of the voltage transformer in real time, as well as the initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On one hand, using the voltage transmission unit of the black-box inverse model, the device calculates the real-time primary voltage based on the real-time secondary voltage, initial load impedance, generalized short-circuit impedance, and auxiliary impedance. On the other hand, it calculates the load current variation difference and uses the generalized short-circuit impedance unit of the black-box inverse model to calculate the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance. The real-time primary voltage is corrected based on the calculated compensation voltage to obtain the compensated primary voltage of the voltage transformer. The device then performs primary voltage compensation control on the voltage transformer based on the compensated primary voltage. This invention performs frequency response distortion compensation analysis based on a black-box inverse model with embedded generalized short-circuit impedance, considering the voltage transmission characteristic of the voltage transformer, which effectively improves the accuracy of the compensation voltage and thus enhances the effect of frequency response distortion compensation.

[0206] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A frequency response distortion compensation method based on a black-box inverse model, characterized in that, include: When frequency response distortion of the secondary voltage waveform of the voltage transformer is detected, the actual load impedance and real-time secondary voltage of the voltage transformer are collected in real time. The initial load impedance, generalized short-circuit impedance, and auxiliary impedance of the voltage transformer are obtained respectively. Using the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance. Based on the actual load impedance, the real-time secondary voltage, and the initial load impedance, calculate the load current variation difference of the voltage transformer; Using the generalized short-circuit impedance unit of the black-box inverse model, the compensation voltage of the voltage transformer is calculated based on the load current variation difference and the generalized short-circuit impedance. Based on the compensation voltage, the real-time primary voltage is corrected to obtain the compensated primary voltage of the voltage transformer; The voltage transformer is subjected to primary side voltage compensation control based on the compensated primary side voltage.

2. The frequency response distortion compensation method based on the black-box inverse model according to claim 1, characterized in that, The generalized short-circuit impedance is determined in the following way: The secondary winding of the voltage transformer is controlled to be in a short-circuit state. Obtain the transformer ratio of the voltage transformer; The primary side voltage and secondary side short-circuit current of the voltage transformer are detected when the secondary winding is short-circuited. The generalized short-circuit impedance is calculated based on the transformer ratio, the primary voltage, and the secondary short-circuit current.

3. The frequency response distortion compensation method based on the black-box inverse model according to claim 2, characterized in that, The calculation of the generalized short-circuit impedance based on the transformer ratio, the primary voltage, and the secondary short-circuit current includes: The generalized short-circuit impedance is calculated using the following formula: In the formula, Z G U1 is the generalized short-circuit impedance; U2 is the primary side voltage; I2 is the secondary side short-circuit current; k v For the transformer ratio.

4. The frequency response distortion compensation method based on the black-box inverse model according to claim 3, characterized in that, The auxiliary impedance is determined in the following way: The secondary winding of the voltage transformer is controlled to be in an open-circuit state. The no-load voltage transfer characteristic value of the voltage transformer under the open-circuit condition of the secondary winding is detected; The auxiliary impedance is calculated based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value.

5. The frequency response distortion compensation method based on the black-box inverse model according to claim 4, characterized in that, The calculation of the auxiliary impedance based on the generalized short-circuit impedance and the no-load voltage transmission characteristic value includes: The auxiliary impedance is calculated using the following formula: In the formula, Z H For auxiliary impedance; Z G H is the generalized short-circuit impedance; linear_0 This represents the no-load voltage transmission characteristic value.

6. The frequency response distortion compensation method based on the black-box inverse model according to claim 1, characterized in that, The voltage transmission unit utilizing the black-box inverse model calculates the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance, including: Based on the voltage correlation formula between the primary and secondary voltages in the voltage transmission unit of the black-box inverse model, the real-time primary voltage of the voltage transformer is calculated using the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance. The voltage correlation formula is as follows: In the formula, V pZL1 This is the real-time primary side voltage; V sh This refers to the real-time secondary side voltage; Z G Z is the generalized short-circuit impedance; H For auxiliary impedance; Z L1 This is the initial load impedance.

7. The frequency response distortion compensation method based on the black-box inverse model according to claim 1, characterized in that, The calculation of the load current variation difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage, and the initial load impedance includes: Obtain the load current correlation formula between the load current variation difference and the actual load impedance; Based on the load current correlation formula, the load current variation difference of the voltage transformer is calculated using the actual load impedance, the real-time secondary voltage, and the initial load impedance. The load current correlation formula is as follows: In the formula, i s12 V represents the difference in load current variation. sh This refers to the real-time secondary side voltage; Z L Z represents the actual load impedance. L1 This is the initial load impedance.

8. The frequency response distortion compensation method based on the black-box inverse model according to claim 1, characterized in that, The generalized short-circuit impedance unit utilizing the black-box inverse model calculates the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance, including: The compensation voltage calculation formula is obtained from the generalized short-circuit impedance unit of the black box inverse model; Based on the compensation voltage calculation formula, the compensation voltage of the voltage transformer is calculated using the load current variation difference and the generalized short-circuit impedance. The formula for calculating the compensation voltage is as follows: V pZG =Z G ·i s12 In the formula, V pZG For voltage compensation; i s12 Z represents the difference in load current variation. G This is the generalized short-circuit impedance.

9. The frequency response distortion compensation method based on the black-box inverse model according to claim 1, characterized in that, The step of compensating the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer includes: The primary voltage of the voltage transformer after compensation is calculated using the following formula: V ph =V pZL1 +V pZG In the formula, V ph To compensate for the primary side voltage; V pZL1 This is the real-time primary side voltage; V pZG To compensate for the voltage.

10. A frequency response distortion compensation device based on a black-box inverse model, characterized in that, include: The system includes a data acquisition module, a data purchase module, a primary voltage calculation module, a current difference calculation module, a compensation voltage calculation module, a voltage correction module, and a voltage compensation module. The data acquisition module is used to acquire the actual load impedance and real-time secondary voltage of the voltage transformer in real time when frequency response distortion of the secondary voltage waveform of the voltage transformer is detected. The data acquisition module is used to acquire the initial load impedance, generalized short-circuit impedance and auxiliary impedance of the voltage transformer, respectively. The primary voltage calculation module is used to calculate the real-time primary voltage of the voltage transformer based on the real-time secondary voltage, the initial load impedance, the generalized short-circuit impedance, and the auxiliary impedance using the voltage transmission unit of the black-box inverse model. The current difference calculation module is used to calculate the load current change difference of the voltage transformer based on the actual load impedance, the real-time secondary voltage and the initial load impedance; The compensation voltage calculation module is used to calculate the compensation voltage of the voltage transformer based on the load current variation difference and the generalized short-circuit impedance using the generalized short-circuit impedance unit of the black-box inverse model. The voltage correction module is used to correct the real-time primary voltage based on the compensation voltage to obtain the compensated primary voltage of the voltage transformer. The voltage compensation module is used to perform primary-side voltage compensation control on the voltage transformer based on the compensated primary-side voltage.

Images