Power grid voltage phase detection method, device, equipment and medium

Abstract

The embodiment of the invention provides a power grid voltage phase detection method and device, equipment and a medium. The method comprises the steps that a second-order generalized integrator carries out low-pass filtering on a power grid voltage signal, harmonic and direct-current components in the power grid voltage signal are suppressed and filtered for the first time, and direct-current bias and phase bias in the power grid voltage signal are filtered in combination with bias filtering, so that current interference is avoided to the maximum extent; and through transformation processing and a linear expansion state observer, an instantaneous angular frequency corresponding to the current is obtained, and a phase value corresponding to the power grid voltage signal is calculated. The method is used for solving the problem of insufficient accuracy of power grid voltage phase detection in related technologies.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid equipment, and particularly relates to a power grid voltage phase detection method and device, equipment and a medium. BACKGROUND

[0002] For an inverter in a distributed energy system (such as photovoltaic power generation, wind power generation, etc.), in order to safely and effectively inject power into a power grid, the phase and frequency of the current of the power grid need to be accurately detected to ensure that the current output by the inverter is consistent with the phase and frequency of the power grid voltage. Since various renewable energies, that is, the inertia damping of the distributed energy system, are low and more sensitive to various uncertain disturbances, if the current characteristics of the power grid cannot be accurately detected, the grid connection of the distributed energy system will be further affected, thereby causing the safety of the overall power grid.

[0003] In related technologies, ensuring the detection of the phase and frequency of the power grid voltage is mainly achieved by a phase-locked loop cooperating with the inverter, but the anti-interference ability of the phase-locked loop itself is limited, which leads to insufficient accuracy of the power grid voltage phase detection. SUMMARY

[0004] Embodiments of the present application provide a power grid voltage phase detection method, device, equipment and medium to solve the problem of insufficient accuracy of power grid voltage phase detection in related technologies.

[0005] In a first aspect, an embodiment of the present application provides a power grid voltage phase detection method, comprising:

[0006] The power grid voltage signal output by the power grid is input into corresponding second-order generalized integrators, and a voltage corresponding to each phase and a deflection voltage are output, wherein the power grid voltage signal includes three phases, each phase includes a corresponding second-order generalized integrator, and the second-order generalized integrator is used for performing first filtering processing on the power grid voltage;

[0007] The voltage and the deflection voltage are subjected to transformation processing and bias filtering processing to obtain phase parameters after filtering processing, wherein the transformation processing includes Clark transformation and Park transformation, and the bias filtering processing includes direct current bias filtering processing and phase bias filtering processing;

[0008] The phase parameters are input into a linear extended state observer, and a corresponding instantaneous angular frequency is output;

[0009] Based on the instantaneous angular frequency, a phase value corresponding to the power grid voltage signal is obtained.

[0010] In a possible implementation, the voltage and the deflection voltage are transformed and biased filtered to obtain the filtered phase parameter, including: performing Clarke transformation on the voltage and the deflection voltage respectively to obtain the transformed two-phase voltage and two-phase deflection voltage; performing direct current bias filtering and phase bias filtering on the two-phase voltage based on the two-phase deflection voltage to obtain the filtered two-phase deflection voltage; performing Park transformation on the two-phase deflection voltage to obtain the transformed phase parameter.

[0011] In a possible implementation, the two-phase deflection voltage contains a direct current component; the two-phase voltage is filtered based on the two-phase deflection voltage to obtain the filtered two-phase deflection voltage, including: subtracting the two-phase deflection voltage from the two-phase voltage to obtain a corresponding direct current component; subtracting the corresponding direct current component from the two-phase deflection voltage to obtain the two-phase deflection voltage after direct current bias filtering; combining the two-phase voltage and the two-phase deflection voltage after direct current bias filtering and averaging to obtain the two-phase deflection voltage after phase bias filtering.

[0012] In a possible implementation, the phase parameter is input into a linear extended state observer to output a corresponding instantaneous angular frequency, including: obtaining the instantaneous angular frequency at a previous moment as a reference angular frequency; outputting the reference angular frequency and the phase parameter into the linear extended state observer to output the instantaneous angular frequency and a change amount of the instantaneous angular frequency.

[0013] In a possible implementation, the linear extended state observer processes the reference angular frequency and the phase parameter as follows:

[0014] ,

[0015] wherein z1 is used to represent the instantaneous angular frequency, z1 is used to represent the first derivative of the instantaneous angular frequency, z2 is used to represent the change amount of the instantaneous angular frequency, z2 is used to represent the first derivative of the change amount of the instantaneous angular frequency, y is the input phase parameter, u is the reference angular frequency, b0 is a nominal gain of the linear extended state observer, β1 and β2 are correlation coefficients of errors and observation state variables, and U ref is the reference voltage.

[0016] In a possible implementation, the obtaining the phase value corresponding to the grid voltage signal based on the instantaneous angular frequency comprises: determining a phase deviation between the instantaneous angular frequency and the reference voltage, and proportionally adjusting the phase deviation; combining the proportionally adjusted phase deviation and a change amount of the instantaneous angular frequency to obtain a phase deviation after feedforward compensation; performing normalization processing on the phase deviation after feedforward compensation to obtain a reference angular frequency used for calculation of the linear extended state observer at a next moment; combining the reference angular frequency with a disturbance compensation parameter to obtain a phase deviation after disturbance compensation; and integrating the phase deviation to obtain the phase value.

[0017] In a possible implementation, the method further comprises: inputting the phase value into a Park transformation in the transformation processing to obtain the instantaneous angular frequency.

[0018] In a second aspect, an embodiment of the present application provides an apparatus for detecting a grid voltage phase, comprising:

[0019] The obtaining module is configured to input grid voltage signals output by a grid into corresponding second-order generalized integrators respectively, and output a voltage and a deflection voltage corresponding to each phase, wherein the grid voltage signals comprise three phases, each phase comprises a corresponding second-order generalized integrator, and the second-order generalized integrators are configured to perform first filtering processing on the grid voltage signals.

[0020] The transformation module is configured to perform transformation processing and bias filtering processing on the voltage and the deflection voltage to obtain phase parameters after filtering processing, wherein the transformation processing comprises Clarke transformation and Park transformation, and the bias filtering processing comprises direct current bias filtering processing and phase bias filtering processing.

[0021] The detecting module is configured to input the phase parameters into a linear extended state observer to output corresponding instantaneous angular frequencies.

[0022] The determining module is configured to obtain a phase value corresponding to the grid voltage signal based on the instantaneous angular frequency.

[0023] In a possible implementation, the transformation module is specifically configured to perform Clarke transformation processing on the voltage and the deflection voltage respectively to obtain two-phase voltages and two-phase deflection voltages after transformation processing; perform direct current bias filtering processing and phase bias filtering processing on the two-phase voltages respectively based on the two-phase deflection voltages to obtain two-phase deflection voltages after filtering processing; and perform Park transformation processing on the two-phase deflection voltages to obtain the phase parameters after transformation processing.

[0024] In one possible implementation, the conversion module is specifically used to, if the two-phase deflection voltage contains a DC component; subtract the two-phase voltage from the two-phase deflection voltage to obtain the corresponding DC component; subtract the two-phase deflection voltage from the corresponding DC component to obtain the two-phase deflection voltage after DC bias filtering; combine the two-phase voltage and the corresponding two-phase deflection voltage after DC bias filtering and calculate the average to obtain the two-phase deflection voltage after phase bias filtering.

[0025] In one possible implementation, the detection module is specifically configured to obtain an instantaneous angular frequency obtained at a previous moment as a reference angular frequency; output the reference angular frequency and phase parameter to a linear extended state observer, and output the instantaneous angular frequency and the change in the instantaneous angular frequency.

[0026] In a possible implementation, the detection module specifically includes a linear extended state observer processing the reference angular frequency and phase parameters as follows:

[0027] ,

[0028] Among them, z1 is used to represent the instantaneous angular frequency, It is used to represent the first-order derivative of the instantaneous angular frequency, and z2 is used to represent the change in the instantaneous angular frequency. It is used to express the first derivative of the instantaneous angular frequency change, y is the input phase parameter, u is the reference angular frequency, b0 is the nominal gain of the linear expansion state observer, β1 and β2 are the correlation coefficients between the error and the observed state variable, U ref is the reference voltage.

[0029] In one possible implementation, the determination module is specifically used to determine the phase deviation between the instantaneous angular frequency and the reference voltage, and to proportionally adjust the phase deviation; combine the proportionally adjusted deviation with the change in the instantaneous angular frequency to obtain the phase deviation after feedforward compensation; normalize the phase deviation after feedforward compensation to obtain a reference angular frequency for linear extended state observer calculation at the next moment; combine the reference angular frequency with the disturbance compensation parameter to obtain the phase deviation after disturbance compensation; and integrate the phase deviation to obtain a phase value.

[0030] In a possible implementation manner, the transformation module is further configured to input the phase value into a Park transformation in the transformation process to obtain an instantaneous angular frequency.

[0031] In a third aspect, an embodiment of the present application provides a control device, including: a memory, a processor;

[0032] The memory stores computer-executable instructions;

[0033] The processor executes the computer-executed instructions stored in the memory, so that the processor executes the first aspect and / or various possible implementation manners of the first aspect.

[0034] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, wherein computer-executed instructions are stored in the computer readable storage medium, and the computer-executed instructions are executed by a processor to implement the first aspect and / or various possible implementation manners of the first aspect.

[0035] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, wherein the computer program is executed by a processor to implement the first aspect and / or various possible implementation manners of the first aspect.

[0036] The grid voltage phase detection method, device, equipment and medium provided by the embodiments of the present application can maximize the avoidance of current interference by performing low-pass filtering on the grid voltage signal through a second-order generalized integrator, suppressing and performing first filtering on the harmonic and DC component in the grid voltage signal, and then combining bias filtering to filter out the DC bias and phase bias in the grid voltage signal. Then, the instantaneous angular frequency corresponding to the current is obtained through transformation processing and linear extended state observer, and the phase value corresponding to the grid voltage signal is calculated. Thus, through multiple filtering, the accuracy of the obtained phase value is ensured, and through the filtering of the DC bias and phase bias, the method can be applied to the working condition of three-phase DC bias imbalance, thereby improving the application range and accuracy of phase detection. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] Figure 1 An application scenario diagram of the grid voltage phase detection method provided by an embodiment of the present application is shown in the figure.

[0039] Figure 2 A flowchart of the grid voltage phase detection method provided by an embodiment of the present application is shown in the figure.

[0040] Figure 3 A flowchart of the grid voltage phase detection method provided by another embodiment of the present application is shown in the figure.

[0041] Figure 4 A flowchart of the grid voltage phase detection method provided by another embodiment of the present application is shown in the figure. Figure 3 A flowchart of the grid voltage phase detection method provided by another embodiment of the present application is shown in the figure.

[0042] Figure 5 A flowchart of the grid voltage phase detection method provided by another embodiment of the present application is shown in the figure. Figure 3A diagram showing the relationship between the phase and amplitude of the two-phase voltages and the two-phase deflection voltages provided by the illustrated embodiment;

[0043] Figure 6 for Figure 3 The illustrated embodiment provides a logic flow chart for filtering two-phase deflection voltages;

[0044] Figure 7 for Figure 3 The illustrated embodiment provides a flow chart for obtaining a phase value by using a two-phase deflection voltage;

[0045] Figure 8 A schematic structural diagram of a grid voltage phase detection device provided in yet another embodiment of the present disclosure;

[0046] Figure 9 A schematic diagram of the structure of a control device provided in one embodiment of the present disclosure.

[0047] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0048] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0049] To safely and efficiently inject power into the grid, inverters in distributed energy systems (such as photovoltaic and wind power generation) require precise detection of the grid's current phase and frequency to ensure that the inverter's output current aligns with the grid voltage's phase and frequency. Because renewable energy sources, or distributed energy systems, have low inertial damping and are more sensitive to various uncertain disturbances, the inability to accurately detect grid current characteristics can further impact the integration of distributed energy resources, potentially compromising the overall security of the grid.

[0050] In related technologies, the detection of grid voltage phase and frequency is mainly achieved through a phase-locked loop (PLL) in conjunction with the inverter. However, the PLL itself has limited anti-interference capabilities and does not have the function of filtering various current biases, harmonics, and disturbances, resulting in insufficient accuracy in grid voltage phase detection.

[0051] The grid voltage phase detection method provided in the application can effectively avoid the influence of disturbance in the current on phase detection and improve the accuracy and practicality of phase detection by filtering the grid voltage multiple times, then performing transformation processing, and then performing phase detection to obtain the corresponding phase value.

[0052] Figure 1 The application scenario of the grid voltage phase detection method provided in the application is shown in FIG. 1. Figure 1 As shown in the figure, the specific application scenario of the application is that, in the determination of the phase of a grid signal, a phase detection system 100 receives a grid signal input by a grid 110 and outputs a corresponding phase value.

[0053] It should be noted that, Figure 1 The number of grids and phase detection systems in the scenario shown in the figure is only taken as an example or a specific number for example description, but the present disclosure is not limited thereto, that is, the number of grids and phase detection systems can be arbitrary.

[0054] The technical solutions of the application and how the technical solutions of the application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the application will be described below with reference to the drawings.

[0055] Figure 2 The flowchart of the grid voltage phase detection method provided in the application is shown in FIG. 2. Figure 1 As shown in the figure, the method comprises the following steps. Figure 2

[0056] S201, inputting the grid voltage signal output by the grid into corresponding second-order generalized integrators respectively, and outputting the voltage corresponding to each phase and the deflection voltage.

[0057] The grid voltage signal comprises three phases, each phase comprises a corresponding second-order generalized integrator, and the second-order generalized integrator is used for performing first filtering processing on the grid voltage.

[0058] Specifically, the present embodiment is used for generally describing the main steps of grid voltage phase detection.

[0059] The execution subject in the embodiment of the present disclosure is a device, a computer program or a system for detecting the phase of the grid voltage, which is collectively referred to as a system for convenience of description.

[0060] ​The system is usually matched with an inverter of a distributed energy system to monitor the phase and frequency of the grid voltage signal, and then modulate the grid-connected electrical signal output by the distributed energy system according to the phase and frequency of the grid voltage signal, so as to ensure the consistency of the phase and frequency, and avoid abnormality or failure in the grid connection process due to the difference in phase and frequency. That is, the system functions similarly to a phase-locked loop.

[0061] There are three second-order generalized integrators (SOGI) in the system, each corresponding to a phase of the grid voltage signal (the grid voltage signal is a three-phase voltage signal, and the angle difference between each phase of the voltage signal is 120°). After receiving the voltage signal of the corresponding phase, the SOGI outputs two orthogonal voltage signals, one of which is the same as the original voltage signal, and the other voltage signal is 90° different from the corresponding original voltage signal, that is, the deflection voltage.

[0062] At the same time, the SOGI contains a low-pass filter, which can also filter high-order harmonics in the grid voltage signal (but cannot suppress DC bias, low-order harmonics, etc.), that is, the first filtering process.

[0063] S202, transform and bias filtering processing are performed on the voltage and deflection voltage to obtain the phase parameter after filtering processing.

[0064] Among them, the transform processing includes Clark transform and Park transform, and the bias filtering processing includes DC bias filtering processing and phase bias filtering processing.

[0065] Specifically, through the Clark transform, the voltage and deflection voltage can be converted into voltage components in the corresponding two-phase stationary coordinate system; and then through the Park transform, the voltage components can be converted into voltage components in the rotating coordinate system (d-q coordinate system), wherein the voltage component corresponding to the q-axis is used to reflect the deviation between the current angle estimation value and the true value. This voltage component is the phase parameter.

[0066] Since the first filtering of SOGI cannot suppress the DC bias in the voltage signal and other problems, there will be a deviation between the voltage signal and the true result, therefore, the disturbance in each voltage component needs to be filtered out through DC bias filtering and phase bias filtering, so as to ensure the accuracy of the subsequent measured phase value.

[0067] S203, input the phase parameter into the linear extended state observer to output the corresponding instantaneous angular frequency.

[0068] Specifically, the linear extended state observer (LESO) is a device that can measure the angular frequency corresponding to the electrical signal according to the phase parameter.

[0069] Since the grid voltage signal is continuously input into the system, the angular frequency output by the LESO is the real-time angular frequency detected at the current moment, that is, the instantaneous angular frequency.

[0070] In some embodiments of the present disclosure, the LESO observer optimized on the basis of linear active disturbance rejection control (LADRC) can also be used for calculation to improve the anti-interference performance in the process of determining the instantaneous angular frequency.

[0071] S204, based on the instantaneous angular frequency, obtaining the phase value corresponding to the grid voltage signal.

[0072] Specifically, by integrating the instantaneous angular frequency, the phase value of the grid voltage signal can be obtained.

[0073] In actual calculation, disturbance compensation, signal amplification, etc. can be performed on the instantaneous angular frequency before integration to ensure the accuracy and reliability of the calculated phase value.

[0074] At the same time, through the instantaneous angular frequency, the frequency of the grid voltage signal can also be conveniently converted, that is, the instantaneous angular frequency is divided by 2π to obtain the instantaneous frequency of the grid voltage signal.

[0075] The grid voltage phase detection method provided by the embodiments of the present application filters the grid voltage signal through a second-order generalized integrator, suppresses and first filters the harmonic and DC components in the grid voltage signal, combines bias filtering to filter out the DC bias and phase bias in the grid voltage signal, maximizes the interference of the current, and then obtains the instantaneous angular frequency corresponding to the current through transformation processing and linear extended state observer. Further, the phase value corresponding to the grid voltage signal is calculated, thereby ensuring the accuracy of the obtained phase value through multiple filtering, and through the filtering of the DC bias and phase bias, the method can be applied to the working condition of three-phase DC bias imbalance, and the application range and accuracy of phase detection are improved.

[0076] Figure 3 The flowchart of the grid voltage phase detection provided by the present application Figure 2 As shown in Figure 3 the embodiment is based on Figure 2 the embodiment, the specific implementation process of the grid voltage phase detection method is described in detail, and the method comprises:

[0077] S301, input the grid voltage signal output by the grid into corresponding second-order generalized integrators respectively, and output voltage and deflection voltage corresponding to each phase.

[0078] The grid voltage signal includes three phases, each phase includes a corresponding second-order generalized integrator, and the second-order generalized integrator is used for first filtering processing of the grid voltage.

[0079] Specifically, the embodiment is used for further detailed description of specific steps in grid voltage phase detection.

[0080] As shown in Figure 4 , it is a flowchart of SOGI and Clarke transformation processing of the grid voltage signal.

[0081] In combination Figure 4 , after receiving the grid voltage signal, the system processes the grid three-phase voltage signal through three parallel SOGIs. After the voltage signal of each phase is processed by the SOGI, two signals with the same phase and 90° phase difference are obtained from the original signal, and thus, U, V, and W obtain corresponding voltages U, V, and W and deflection voltages U', V', and W'.

[0082] S302, perform Clarke transformation processing on the voltage and the deflection voltage respectively, and obtain two-phase voltage and two-phase deflection voltage after transformation processing.

[0083] Specifically, in combination Figure 4 , the right side upper and lower two blocks respectively represent Clarke transformation, wherein the upper Clarke transformation is transformation processing on the voltage U, V, and W, to obtain corresponding two-phase voltage U α1 , U β1 in the two-phase stationary coordinate system, and the lower Clarke transformation is transformation processing on the deflection voltage U', V', and W', to obtain corresponding two-phase deflection voltage U α2 , U β2 in the two-phase stationary coordinate system.

[0084] S303, based on the two-phase deflection voltage, perform direct current bias filtering processing and phase bias filtering processing on the two-phase voltage respectively, and obtain two-phase deflection voltage after filtering processing.

[0085] Specifically, in an ideal case, if the direct current components of the three-phase voltage are the same, the two-phase deflection voltage after Clarke transformation does not contain direct current components, but in the actual situation, there may be an unbalanced situation of the direct current components of the three-phase voltage, at this time, the two-phase deflection voltage after Clarke transformation will contain direct current bias and phase bias, which affects the tracking performance of the system.

[0086] Because the two-phase deflection voltage contains DC component, the two-phase voltage needs to be filtered, as shown in Figure 5 , which is a phase amplitude relationship diagram of the two-phase voltage and the two-phase deflection voltage, as shown in Figure 6 , which is a logic flow chart of filtering the two-phase deflection voltage, combined with Figure 5 and Figure 6 , the specific filtering process includes the following steps:

[0087] Step A1, difference between the two-phase voltage and the two-phase deflection voltage to obtain the corresponding DC component.

[0088] Specifically, as in Figure 5 , U1 and U2 are two voltage signals corresponding to three-phase power grid voltage signals in the two-phase stationary coordinate system, as shown in the figure, at this time, the phase difference between the two-phase deflection voltage and the corresponding two-phase voltage is 90°, and at the same time, U β1 and U α2 are equal in value, U α1 and U β1 are opposite numbers (the calculation process of Clark transformation is existing technology in the art, which will not be repeated here).

[0089] Therefore, subtracting U β2 from U α1 (only adding them together is needed because U β2 is negative, so the corresponding operation in Figure 6 is to add them together), the corresponding DC component of U β2 can be obtained.

[0090] Similarly, subtracting U α2 from U β1 , the corresponding DC component of U β1 can be obtained.

[0091] Step A2, difference between the two-phase deflection voltage and the corresponding DC component to obtain the two-phase deflection voltage after DC bias filtering.

[0092] Specifically, by subtracting the corresponding DC component from the two-phase voltage, the two-phase deflection voltage after DC bias filtering can be obtained.

[0093] In Figure 6 , subtracting the corresponding DC component obtained in the previous step from U α2 , the two-phase deflection voltage U α1 ′ after removing the DC bias filter can be obtained, and similarly, subtracting the corresponding DC component obtained in the previous step from U β2 , the two-phase deflection voltage U β1 ′ after removing the DC bias filter can be obtained.

[0094] Step A3: Combine the two-phase voltages with the corresponding two-phase deflection voltages after DC offset filtering and calculate the average to obtain the two-phase deflection voltages after phase offset filtering.

[0095] Specifically, in addition to the DC offset, the voltage signal actually also contains a phase offset, which also affects the accuracy of the subsequent phase value determination. Therefore, it is necessary to combine each two-phase voltage with the corresponding two-phase deflection voltage after DC offset filtering and then average them to eliminate the influence of the phase offset.

[0096] Combine Figure 6 In the middle, use U α1 Subtract the two-phase deflection voltage U obtained in the previous step after removing the DC offset filter α1 ′, and then calculate the average of the results (i.e. multiply by 0.5), we can get the two-phase deflection voltage U after phase offset filtering. α , similarly, we can get β1 The corresponding two-phase deflection voltage U after phase offset filtering β .

[0097] S304 , performing Park transformation on the two-phase deflection voltages to obtain transformed phase parameters.

[0098] Specifically, such as Figure 7 As shown in FIG, it is a flow chart of obtaining the phase value by the two-phase deflection voltage. The two-phase deflection voltage U after the phase offset filtering process in the above steps is α and U β to the Park transformation (i.e. Figure 7 The two-phase deflection voltage can be converted into the voltage component V in the rotating coordinate system through Park transformation. d and V q .

[0099] Among them, V q It represents the voltage component of the q-axis in the rotating coordinate system, and also represents the synchronization error (i.e., phase parameter) between the current angle estimate and the true angle. Combined with the phase value at the previous moment, it is corrected to obtain the difference between the phase value at the current moment and the phase value at the previous moment. By correcting this difference, the angular frequency at the current moment, i.e., the instantaneous angular frequency, can be obtained.

[0100] Therefore, in actual calculation, it is necessary to obtain the phase value at the previous moment and input the phase value into the Park transform in the transformation process to determine the phase parameter at the current moment.

[0101] S305: Obtain the instantaneous angular frequency obtained at the previous moment as a reference angular frequency.

[0102] Specifically, according to the foregoing analysis, after obtaining the phase parameter, the instantaneous angular frequency at the current moment needs to be calculated by combining the angular frequency at the previous moment, and then the phase value at the current moment is calculated.

[0103] Therefore, before the next calculation is performed, the instantaneous angular frequency obtained at the previous moment needs to be obtained as a reference angular frequency, so as to perform subsequent calculation.

[0104] The reference angular frequency can be obtained from the LESO output at the previous moment. The angular frequency value of the LESO output is stored in the system cache, so as to be called in subsequent calculation.

[0105] Reference Figure 7 In the figure, the value from the top to the LESO block is the reference angular frequency.

[0106] S306, output the reference angular frequency and the phase parameter to the linear extended state observer respectively, output the instantaneous angular frequency and the change amount of the instantaneous angular frequency.

[0107] Specifically, the reference angular frequency and the V q are input into the LESO, so as to obtain the instantaneous angular frequency at the current moment and the first derivative thereof, that is, the change amount of the instantaneous angular frequency.

[0108] In some embodiments of the present disclosure, the conventional LESO is good at detecting the deviation between the instantaneous angular frequency and the reference angular frequency, but is prone to deviation in detecting the deviation between the change amount of the instantaneous angular frequency and the corresponding actual value. In the related art, the LESO corresponding observer parameters (such as the correlation coefficient of the error and the observation state variable) are usually selected to increase to ensure the detection accuracy of the change amount of the instantaneous angular frequency, but this will cause the dynamic performance of the LESO to be insufficient, thereby affecting the reliability of the LESO in power grid phase identification.

[0109] Therefore, in the present scheme, the LESO detector based on the improved LADRC is actually used for detection, and at this time, the calculation method is as follows:

[0110] The processing of the reference angular frequency and the phase parameter by the linear extended state observer is represented as:

[0111] ,

[0112] Among them, z1 is used to represent the instantaneous angular frequency, is used to represent the first derivative of the instantaneous angular frequency, z2 is used to represent the change amount of the instantaneous angular frequency, is used to represent the first derivative of the change amount of the instantaneous angular frequency, and y is the input phase parameter (here, the corresponding formula of the improved LESO detector is given. In actual operation, it can be directly replaced by V q), u is the reference angular frequency, b0 is the nominal gain of the linear extended state observer, β1 and β2 are the correlation coefficients between the error and the observed state variable, U ref is the reference voltage.

[0113] In actual calculations, β1 and β2 can be taken as 2ω0 and ω0 respectively. 2 , ω0 is the bandwidth configured by the system, and both b0 and ω0 can be adjusted according to actual computing requirements to ensure the accuracy of detection.

[0114] Reference voltage U ref It is usually 0.

[0115] S307 : Determine the phase deviation between the instantaneous angular frequency and the reference voltage, and perform proportional adjustment on the phase deviation.

[0116] Specifically, the instantaneous angular frequency obtained through the above steps can be integrated to obtain the phase value, but in order to improve the accuracy of the calculation results.

[0117] The reference voltage ( Figure 7 U in ref ) is corrected (i.e., subtracted) and then applied by a pre-configured proportional gain ( Figure 7 ), adjust it to reduce the tracking error.

[0118] S308 : Combining the deviation after proportional adjustment with the change in instantaneous angular frequency to obtain a phase deviation after feedforward compensation.

[0119] Specifically, the result after proportional adjustment is compared with the change in the instantaneous angular frequency output by LESO (i.e. Figure 7 The combination (i.e., addition) of z2) can improve the dynamic response performance of the result, that is, the phase deviation after feedforward compensation is obtained.

[0120] S309 , normalizing the phase deviation after feedforward compensation to obtain a reference angular frequency for linear extended state observer calculation at the next moment.

[0121] Specifically, the phase deviation obtained in the above steps is normalized (multiplied by 1 / b0) to obtain a reference angular frequency that can be used for feedback to the LESO.

[0122] S310 : Combining the reference angular frequency with the disturbance compensation parameter to obtain a phase deviation after disturbance compensation.

[0123] Specifically, the reference angular frequency and the disturbance compensation parameter ( Figure 7 Chinese g ) are combined (here they are subtracted) to offset constant disturbances (such as gravity, friction, etc.), thereby obtaining the phase deviation after disturbance compensation.

[0124] The disturbance compensation parameters are also pre-configured values ​​in the system (in fact, the pre-configured parameters of the above system are all common parameters in the relevant technology, and their configuration and adjustment methods are all existing technologies and will not be repeated here). Those skilled in the art can adjust them according to actual conditions.

[0125] S311. Integrate the phase deviation to obtain a phase value.

[0126] Specifically, by integrating the phase deviation obtained in the previous step, a phase value with anti-interference and fast response capabilities can be obtained, thereby maximizing the accuracy of the results obtained from the grid voltage signal.

[0127] In some embodiments of the present disclosure, the reference angular frequency obtained above can also be converted to the frequency of the grid voltage signal (i.e., ω in the figure, the conversion principle has been described in the previous steps and will not be repeated here). Finally, the frequency and phase value can be output together to control the electrical signal output by the inverter based on the frequency and phase value of the grid.

[0128] The grid voltage phase detection method provided in the embodiments of the present application performs SOGI processing on the grid voltage signal, then passes it through Clarke transform, DC offset filtering, phase offset filtering, and Park transform. The resulting signal is then output to an improved LESO. Finally, the output instantaneous angular frequency is adjusted and integrated to obtain the final phase value. This maximizes the anti-interference capability and accuracy of the obtained phase value.

[0129] Figure 8 This is a schematic diagram of the structure of the grid voltage phase detection device provided in this application, as shown in Figure 8 As shown, the grid voltage phase detection device 400 provided in this embodiment includes:

[0130] An acquisition module 410 is configured to input the grid voltage signals output by the grid into corresponding second-order generalized integrators, and output the voltage corresponding to each phase and the deflection voltage. The grid voltage signal includes three phases, and each phase includes a corresponding second-order generalized integrator. The second-order generalized integrator is configured to perform a first filtering process on the grid voltage.

[0131] a transformation module 420 for performing transformation processing and bias filtering processing on the voltage and the deflection voltage to obtain a phase parameter after filtering, wherein the transformation processing includes Clarke transformation and Park transformation, and the bias filtering processing includes DC bias filtering processing and phase bias filtering processing;

[0132] The detection module 430 is used to input the phase parameter into the linear extended state observer and output the corresponding instantaneous angular frequency;

[0133] The determination module 440 is configured to obtain a phase value corresponding to the grid voltage signal based on the instantaneous angular frequency.

[0134] In a possible implementation, the transformation module 420 is specifically configured to perform Clarke transformation on the voltage and the deflection voltage respectively to obtain two-phase voltage and two-phase deflection voltage after transformation processing; perform direct current bias filtering processing and phase bias filtering processing on the two-phase voltage based on the two-phase deflection voltage to obtain two-phase deflection voltage after filtering processing; and perform Park transformation on the two-phase deflection voltage to obtain phase parameters after transformation processing.

[0135] In a possible implementation, the transformation module 420 is specifically configured to, if the two-phase deflection voltage contains a direct current component; obtain a corresponding direct current component by subtracting the two-phase deflection voltage from the two-phase voltage; obtain two-phase deflection voltage after direct current bias filtering processing by subtracting the two-phase deflection voltage from the corresponding direct current component; and obtain two-phase deflection voltage after phase bias filtering processing by combining the two-phase voltage and the two-phase deflection voltage after direct current bias filtering processing and taking an average.

[0136] In a possible implementation, the detection module 430 is specifically configured to obtain the instantaneous angular frequency at a previous moment as a reference angular frequency; and output the reference angular frequency and the phase parameters to a linear extended state observer to output the instantaneous angular frequency and a change amount of the instantaneous angular frequency.

[0137] In a possible implementation, the detection module 430 specifically includes that the linear extended state observer processes the reference angular frequency and the phase parameters as follows:

[0138]

[0139] wherein z1 is used to represent the instantaneous angular frequency, is used to represent the first derivative of the instantaneous angular frequency, z2 is used to represent the change amount of the instantaneous angular frequency, is used to represent the first derivative of the change amount of the instantaneous angular frequency, y is the input phase parameter, u is the reference angular frequency, b0 is a nominal gain of the linear extended state observer, β1 and β2 are correlation coefficients of errors and observation state variables, and U ref is the reference voltage.

[0140] ​In one possible embodiment, the determination module 440 is specifically used to determine the phase deviation between the instantaneous angular frequency and the reference voltage, and proportionally adjust the phase deviation; combine the proportionally adjusted deviation with the change in the instantaneous angular frequency to obtain the phase deviation after feedforward compensation; normalize the phase deviation after feedforward compensation to obtain a reference angular frequency for linear extended state observer calculation at the next moment; combine the reference angular frequency with the disturbance compensation parameter to obtain the phase deviation after disturbance compensation; and integrate the phase deviation to obtain a phase value.

[0141] In a possible implementation, the transformation module 440 is further configured to input the phase value into a Park transform in the transformation process to obtain an instantaneous angular frequency.

[0142] The grid voltage phase detection device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effects are similar, and are not described in detail in this embodiment.

[0143] Figure 9 This is a schematic diagram of the structure of the control device provided in this application. Figure 9 As shown, the control device 50 provided in this embodiment includes: at least one processor 501 and a memory 502. Optionally, the device 50 further includes a communication component 503. The processor 501, the memory 502 and the communication component 503 are connected via a bus 504.

[0144] In a specific implementation process, at least one processor 501 executes the computer-executable instructions stored in the memory 502, so that the at least one processor 501 performs the above method.

[0145] The specific implementation process of the processor 501 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0146] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASICs), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly executed by a hardware processor or by a combination of hardware and software modules within the processor.

[0147] The memory can include a Random Access Memory (RAM) and can also include a Non-volatile Memory (NVM), such as at least one disk memory.

[0148] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application does not limit to only one bus or one type of bus.

[0149] The present application also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the above method.

[0150] The present application also provides a computer readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the above method is implemented.

[0151] The above readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0152] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an Application Specific Integrated Circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0153] The division of units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0154] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, can be located in one place, or can be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0155] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0156] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0157] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various program code storage media.

[0158] It should be understood that many of the materials and devices exemplified in this disclosure are articles of manufacture (i.e., articles of manufacture) according to this disclosure. The articles of manufacture can be manufactured as such or can be manufactured by combining the materials and devices exemplified in this disclosure. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It should be understood that, in some embodiments, equivalents to the specific electrode structures and / or methods described herein can be employed without departing from the scope of the application. Accordingly, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," "containing," "involving," "characterized by," "characterized into," and variations thereof herein, is meant to encompass the items listed thereafter, and equivalents thereof as well as additional items. Although the foregoing application has been described in some detail by way of illustration and example, it is not to be limited thereby, but rather, only by the scope of the appended claims.

Claims

1. A method for detecting a grid voltage phase, characterized in that: include: Inputting the grid voltage signals output by the grid into corresponding second-order generalized integrators respectively, and outputting the voltage corresponding to each phase and the deflection voltage, wherein the grid voltage signal includes three phases, each phase includes a corresponding second-order generalized integrator, and the second-order generalized integrator is used to perform a first filtering process on the grid voltage; Performing transformation processing and bias filtering processing on the voltage and the deflection voltage to obtain a phase parameter after filtering, wherein the transformation processing includes Clarke transformation and Park transformation, and the bias filtering processing includes DC bias filtering processing and phase bias filtering processing; Inputting the phase parameter into a linear extended state observer and outputting the corresponding instantaneous angular frequency; Based on the instantaneous angular frequency, a phase value corresponding to the grid voltage signal is obtained.

2. The method according to claim 1, characterized in that Performing transformation processing and bias filtering processing on the voltage and the deflection voltage to obtain a filtered phase parameter includes: Performing Clarke transform processing on the voltage and the deflection voltage respectively to obtain two-phase voltage and two-phase deflection voltage after the transform processing; Based on the two-phase deflection voltages, performing DC bias filtering processing and phase bias filtering processing on the two-phase voltages respectively to obtain filtered two-phase deflection voltages; Performing Park transformation on the two-phase deflection voltages to obtain transformed phase parameters.

3. The method according to claim 2, characterized in that The two-phase deflection voltage contains a DC component; The step of performing DC bias filtering and phase bias filtering on the two-phase deflection voltages to obtain filtered two-phase deflection voltages comprises: Difference between the two-phase voltage and the two-phase deflection voltage to obtain the corresponding DC component; Subtracting the two-phase deflection voltage from the corresponding DC component to obtain the two-phase deflection voltage after DC bias filtering; The two-phase voltages are combined with the two-phase deflection voltages after the corresponding DC offset filtering process and averaged to obtain the two-phase deflection voltages after the phase offset filtering process.

4. The method according to any one of claims 1 to 3, characterized in that The phase parameter is input into the linear extended state observer, and the corresponding instantaneous angular frequency is output, including: Obtain the instantaneous angular frequency at the previous moment as the reference angular frequency; The reference angular frequency and the phase parameter are respectively output to a linear extended state observer, and the instantaneous angular frequency and the variation of the instantaneous angular frequency are output.

5. The method according to claim 4, characterized in that The processing of the reference angular frequency and phase parameters by the linear extended state observer is expressed as: ， Among them, z1 is used to represent the instantaneous angular frequency, It is used to represent the first-order derivative of the instantaneous angular frequency, and z2 is used to represent the change in the instantaneous angular frequency. It is used to express the first derivative of the instantaneous angular frequency change, y is the input phase parameter, u is the reference angular frequency, b0 is the nominal gain of the linear expansion state observer, β1 and β2 are the correlation coefficients between the error and the observed state variable, U ref is the reference voltage.

6. The method according to claim 5, characterized in that The obtaining, based on the instantaneous angular frequency, a phase value corresponding to the grid voltage signal, includes: determining a phase deviation between the instantaneous angular frequency and a reference voltage, and proportionally adjusting the phase deviation; Combining the deviation after proportional adjustment with the change in instantaneous angular frequency, the phase deviation after feedforward compensation is obtained; The phase deviation after feedforward compensation is normalized to obtain the reference angular frequency used for the calculation of the linear extended state observer at the next moment; The reference angular frequency is combined with the disturbance compensation parameter to obtain the phase deviation after disturbance compensation; The phase deviation is integrated to obtain the phase value.

7. The method according to claim 6, characterized in that The method further comprises: The phase value is input into the Park transform in the transform process to obtain the instantaneous angular frequency.

8. A power grid voltage phase detection device, characterized in that: include: an acquisition module, configured to input the grid voltage signals output by the grid into corresponding second-order generalized integrators, and output the voltage corresponding to each phase and the deflection voltage, wherein the grid voltage signal includes three phases, each phase includes a corresponding second-order generalized integrator, and the second-order generalized integrator is used to perform a first filtering process on the grid voltage; a transformation module, configured to perform transformation processing and bias filtering processing on the voltage and the deflection voltage to obtain a phase parameter after filtering, wherein the transformation processing includes Clarke transformation and Park transformation, and the bias filtering processing includes DC bias filtering processing and phase bias filtering processing; A detection module, configured to input the phase parameter into a linear extended state observer and output a corresponding instantaneous angular frequency; A determination module is used to obtain a phase value corresponding to the grid voltage signal based on the instantaneous angular frequency.

9. A control device, characterized in that: include: Memory, processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

Images