Method for estimating specified time parameters of an unknown frequency sinusoidal signal

Abstract

The application discloses a specified time parameter estimation method of frequency-unknown sinusoidal signal and belongs to the technical field of signal estimation and processing. The method comprises the following steps: S1, initializing the parameters of the designed specified time estimator; S2, sampling the input sinusoidal signal according to the time interval specified in S1 to obtain original data; S3, using the specified time estimator of frequency-unknown sinusoidal signal to obtain the data of the state variable of the sinusoidal signal; and S4, estimating the frequency, amplitude, phase angle and initial phase of the sinusoidal signal according to the data of the state variable of the sinusoidal signal in S3. The designed estimator is suitable for any physical system with sinusoidal signal, such as power grid, motor driving system and the like, and has very wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of signal estimation and processing technology, and more specifically, relates to a method for estimating a specified time parameter of a sinusoidal signal with an unknown frequency. Background Technology

[0002] Sinusoidal signals are widely present in many practical engineering fields, including electric vehicle charging stations, power grids, and motor drive systems, and have received considerable attention. Parameter estimation of sinusoidal signals plays a crucial role in both theory and application for accurate tracking and suppression. Therefore, many algorithms have been proposed for estimating sinusoidal signals over the past few decades, such as Fourier analysis, robust spectrum analysis, adaptive filter techniques, phase-locked loop (PLL) methods, and frequency-locked loop (FLL) methods. Most of these sinusoidal signal estimation methods have an infinite convergence time for the estimation error, thus only achieving asymptotic stability. To accelerate convergence and improve tracking accuracy, parameter estimation of sinusoidal signals within a finite time interval has been studied. However, the convergence time of these finite-time detection methods depends on the initial conditions of the sinusoidal signal, making it difficult to estimate sinusoidal signals with unknown initial conditions within a predetermined time period. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a scheme for estimating a sinusoidal signal with an unknown frequency at a specified time, which can quickly and accurately estimate a sinusoidal signal with an unknown frequency within a specified time.

[0004] To address at least one of the aforementioned technical problems, according to one aspect of the present invention, a method for estimating a specified time parameter of a sinusoidal signal with an unknown frequency is provided, comprising the following steps:

[0005] S1. Initialize the parameters of the designed time estimator;

[0006] S2. Sample the input sinusoidal signal according to the time interval specified in S1 to obtain the raw data;

[0007] S3. Use a specified time estimator for a sinusoidal signal with an unknown frequency to obtain data on the state variables of the sinusoidal signal;

[0008] S4. Based on the sinusoidal signal state variable data in S3, estimate the frequency, amplitude, phase angle, and initial phase of the sinusoidal signal through calculation.

[0009] Preferably, step S1 is as follows:

[0010] S11、 Initialize the constant τ within the specified range;

[0011] S12. According to the formulas α1=1+τ, α2=1+2τ, α3=1+3τ respectively (1)

[0012] Initialize constants α1, α2, α3;

[0013] S13. Initialize appropriate positive estimator gain constants k1, k2, k3;

[0014] S14. Initialize the pre-specified convergence time T;

[0015] S15. Initialize the switching time T0 of the specified time estimator;

[0016] S16. Initialize the initial conditions for the specified time estimator

[0017] Preferably, the specified time estimator for the unknown frequency sinusoidal signal used in S3 is as follows:

[0018] When time t is less than the switching time T0, the specified time estimator structure for the unknown frequency sinusoidal signal is as follows:

[0019]

[0020] When time t is greater than or equal to switching time T0, the specified time estimator structure for the unknown frequency sinusoidal signal is as follows:

[0021]

[0022] Preferably, the specific steps of step S4 are as follows:

[0023] S41. Use the state variable data estimated in S3. The estimated frequency of the sinusoidal signal can be calculated using the following formula:

[0024]

[0025] S42. Use the state variable data estimated in S3. The estimated value of the sinusoidal signal amplitude can be calculated using the following formula:

[0026]

[0027] S43. Use the state variable data estimated in S3. The estimated value of the phase angle of the sinusoidal signal can be calculated using the following formula:

[0028]

[0029] S43. Use the state variable data estimated in S3. The estimated value of the initial phase of the sinusoidal signal can be calculated using the following formula:

[0030]

[0031] According to another aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the method for estimating a specified time parameter of a sinusoidal signal of unknown frequency according to the present invention.

[0032] According to another aspect of the present invention, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the steps in the method for estimating a specified time parameter of a sinusoidal signal with an unknown frequency according to the present invention.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] The method for estimating the specified time parameter of a sinusoidal signal with an unknown frequency according to the present invention, compared with the finite-time sinusoidal signal estimation method, has a predefined estimation time, does not depend on the sinusoidal signal and the initial value of the estimator, and can meet the need for rapid estimation of sinusoidal signals. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0036] Figure 1 This is a flowchart of the method of the present invention;

[0037] Figure 2 The simulation results of frequency estimation error in finite-time estimation schemes for sinusoidal signals of unknown frequency with different amplitudes are shown.

[0038] Figure 3 The figure shows the simulation results of amplitude estimation error in finite-time estimation schemes for sinusoidal signals of unknown frequency with different amplitudes.

[0039] Figure 4 The simulation results of phase angle estimation error in finite-time estimation schemes for sinusoidal signals of unknown amplitude and frequency are shown.

[0040] Figure 5 The figure shows the simulation results of the initial phase estimation error in a finite-time estimation scheme for sinusoidal signals of unknown amplitude and frequency.

[0041] Figure 6 The above is a simulation diagram of the frequency estimation error in a specified time estimation scheme for sinusoidal signals of unknown frequency and different amplitudes.

[0042] Figure 7The figure shows the simulation results of amplitude estimation error in a specified time estimation scheme for sinusoidal signals of unknown frequency with different amplitudes.

[0043] Figure 8 The simulation results of phase angle estimation error in a specified time estimation scheme for sinusoidal signals of unknown amplitude and frequency are shown.

[0044] Figure 9 This is a simulation result of the initial phase estimation error in a specified time estimation scheme for sinusoidal signals of unknown amplitude and frequency. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

[0046] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0047] like Figure 1-9 As shown,

[0048] Example 1:

[0049] The sinusoidal signal to be estimated is y = a0sin(ω0t + δ0) = a0sin(θ(t)), where ω0, a0, θ(t), and δ0 are the frequency, amplitude, phase angle, and initial phase of the sinusoidal signal, respectively. In the simulation, three sets of sinusoidal signals with different amplitudes are selected for analysis and comparison. They have the same frequency ω0 = 2π and initial phase δ0 = 0, and amplitudes a0 of 5, 10, and 15, respectively.

[0050] Choose state variables x1 = a0sin(ω0t + δ0) and x2 = a0ω0cos(ω0t + δ0). The sinusoidal signal was remodeled into the following form:

[0051]

[0052] For the three sets of sinusoidal signals with different amplitudes mentioned above, the state variable x3 = 4π 2 The initial values ​​of state variables x1 and x2 are chosen as x1(0) = 0, x2(0) = 10π, x1(0) = 0, x2(0) = 20π, and x1(0) = 0, x2(0) = 30π, respectively.

[0053] The estimation of the aforementioned unknown frequency sinusoidal signal includes the following steps:

[0054] Step 1: Initialize the parameters of the designed time estimator. First, select constants. Calculate using the formula Secondly, the gain constants of the positive estimator are chosen as k1 = 50, k2 = 150, and k3 = 150; then, the convergence time T = 0.3 seconds and the switching time T0 = 0.29 seconds of the time estimator are specified in advance; finally, the initial conditions of the estimator are set.

[0055] Step 2: Set a time interval of 0.0001 seconds to sample the input sine wave signal to obtain the raw data;

[0056] Step 3: Use a specified time estimator for a sinusoidal signal with an unknown frequency to obtain the data of the sinusoidal signal state variables;

[0057] When time t is less than the switching time T0, the structure of a specified time estimator for an unknown frequency sinusoidal signal is as follows:

[0058]

[0059] When time t is greater than or equal to switching time T0, the structure of a specified time estimator for an unknown frequency sinusoidal signal is as follows:

[0060]

[0061] Step 4: Use the state variable data estimated in Step 3 The frequency, amplitude, phase angle, and initial phase of the sinusoidal signal are estimated through calculation.

[0062] First, the estimated frequency of the sinusoidal signal is calculated using the following formula:

[0063]

[0064] Secondly, the estimated value of the sinusoidal signal amplitude is calculated using the following formula:

[0065]

[0066] Then, the estimated value of the phase angle of the sinusoidal signal is calculated using the following formula:

[0067]

[0068] Finally, the estimated value of the initial phase of the sinusoidal signal is calculated using the following formula:

[0069]

[0070] To better verify the method for estimating specified time parameters of a sinusoidal signal with unknown frequency disclosed in this invention, we define the estimation errors for frequency, amplitude, phase angle, and initial phase as follows: and Furthermore, a finite-time parameter estimation method for a sinusoidal signal with unknown frequency was used for comparative verification. For any time t, the observer structure of this scheme is as follows:

[0071]

[0072] The selected parameters and initial conditions are consistent with those given in step one of this invention.

[0073] Simulation results of estimation errors for frequency, amplitude, phase angle, and initial phase in finite-time estimation schemes for sinusoidal signals of different amplitudes are as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown in the figure; in a specified time estimation scheme for sinusoidal signals with known amplitudes and frequencies, the simulation results of the estimation errors for frequency, amplitude, phase angle, and initial phase are respectively as follows. Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown, this confirms the rationality of the present invention.

[0074] Example 2:

[0075] The computer-readable storage medium of this embodiment stores a computer program that, when executed by a processor, implements the steps in the method for estimating the specified time parameters of a sinusoidal signal with an unknown frequency in Embodiment 1.

[0076] The computer-readable storage medium in this embodiment can be an internal storage unit of the terminal, such as the terminal's hard disk or memory; the computer-readable storage medium in this embodiment can also be an external storage device of the terminal, such as a plug-in hard disk, smart memory card, secure digital card, flash memory card, etc. equipped on the terminal; furthermore, the computer-readable storage medium can include both the terminal's internal storage unit and external storage devices.

[0077] The computer-readable storage medium of this embodiment is used to store computer programs and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0078] Example 3:

[0079] The computer device of this embodiment includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the method for estimating the specified time parameters of a sinusoidal signal with an unknown frequency in Embodiment 1.

[0080] In this embodiment, the processor can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The memory can include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0081] Those skilled in the art will understand that the content disclosed in the embodiments can be provided as a method, system, or computer program product. Therefore, this solution can take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this solution can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage) containing computer-usable program code.

[0082] This solution is described with reference to flowchart illustrations and / or block diagrams of methods and computer program products according to embodiments of this solution. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0084] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0085] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0086] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A method for estimating a specified time parameter of a sinusoidal signal with an unknown frequency, characterized in that, Includes the following steps: S1. Initialize the parameters of the specified time interval estimator; S2. Sample the input sinusoidal signal according to the time interval specified in S1 to obtain the raw data; S3. Use a specified time estimator for a sinusoidal signal with an unknown frequency to obtain data on the state variables of the sinusoidal signal; S4. Based on the sinusoidal signal state variable data in S3, estimate the frequency, amplitude, phase angle, and initial phase of the sinusoidal signal through calculation; The specified time estimator for the unknown frequency sinusoidal signal used in S3 is as follows: When time Less than switching time The structure of the specified time estimator for the unknown frequency sinusoidal signal is as follows: (2) When time greater than or equal to switching time The structure of the specified time estimator for the unknown frequency sinusoidal signal is as follows: (3)。 2. The method according to claim 1, characterized in that, Step S1 is as follows: S11, in Initialization constants within range ; S12, according to the formula respectively , , (1) Initialization constants , , ; S13. Initialize a suitable positive estimator gain constant. , , ; S14. Initialize the pre-specified convergence time. ; S15. Initialize the switching time of the specified time estimator. ; S16. Initialize the initial conditions for the specified time estimator , , .

3. The method according to claim 1, characterized in that, The specific steps of step S4 are as follows: S41. Use the state variable data estimated in S3. , , The estimated frequency of the sinusoidal signal can be calculated using the following formula: （4）； S42. Use the state variable data estimated in S3. , , The estimated value of the sinusoidal signal amplitude can be calculated using the following formula: （5）； S43. Use the state variable data estimated in S3. , , The estimated value of the phase angle of the sinusoidal signal can be calculated using the following formula: （6）； S43. Use the state variable data estimated in S3. , , The estimated value of the initial phase of the sinusoidal signal can be calculated using the following formula: （7）。 4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the steps in the method for estimating the specified time parameters of a sinusoidal signal with an unknown frequency as described in any one of claims 1 to 3.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the method for estimating the specified time parameters of a sinusoidal signal with an unknown frequency as described in any one of claims 1 to 3.

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