ATSE power supply fundamental voltage calculation method based on Goertzel algorithm

Abstract

The invention relates to the technical field of three-phase power supply fundamental wave voltage calculation methods, and discloses an ATSE power supply fundamental wave voltage calculation method based on a Goertzel algorithm, which comprises the following steps: data acquisition: acquiring AD data of three-phase voltage of a power supply according to a fixed sampling rate through a sampling circuit of a controller; setting parameters: setting an initial frequency of frequency detection, a period number k = 1 and a sampling number N of each period; common variables are calculated, wherein the common variables of the Goertzel algorithm are calculated through a twiddle factor # imgabs0 # imgabs1 # and a twiddle factor # imgabs2 #; resampling operation: carrying out resampling operation on each sampling point according to a set frequency; and convolution operation: sequentially carrying out convolution operation on the resampled AD data. According to the method, the discrete Fourier transform is regarded as a group of filters through the Goertzel algorithm, so that the problem of relatively large delay caused by the fact that most of the existing three-phase power supply fundamental wave calculation methods widely applied to dual-power automatic change-over switch products in the market adopt the FFT algorithm is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of three-phase power supply fundamental voltage calculation methods, and in particular to an ATSE power supply fundamental voltage calculation method based on a Goertzel algorithm. Background Art

[0002] The dual power automatic transfer switch is crucial for monitoring the three-phase power supply voltage. During normal operation, the voltage signal of the three-phase power supply is collected in real time through sensing elements such as voltage transformers. The monitoring system will first set the normal working range threshold of the voltage. For example, for the common three-phase 380V system, the upper and lower limits have a certain allowable fluctuation range. When it is detected that the three-phase voltage is within the normal threshold, the dual power automatic transfer switch maintains the current power supply state and does not switch. If one or more phases of voltage are detected to be out of the normal range, such as excessive voltage, it may be caused by power grid fluctuations, lightning strikes, etc., and low voltage may be caused by line faults, excessive voltage drop during peak power consumption, etc. Once the voltage abnormality lasts for a certain period of time and meets the switching condition setting, the dual power automatic transfer switch will start the switching action according to the pre-set logic, switching from the faulty power supply to the backup power supply to ensure that the load continues to obtain stable power. At the same time, the voltage monitoring module can also monitor and analyze parameters such as voltage fluctuation frequency and harmonic content, providing data basis for power system fault diagnosis and power quality assessment, helping to promptly discover potential problems and take corresponding measures to maintain the safe and stable operation of the power system, ensuring that electrical equipment is not damaged by abnormal voltage and maintains normal working efficiency.

[0003] The existing three-phase power fundamental wave calculation methods widely used in dual power automatic transfer switch products on the market mostly use FFT algorithm. This method not only has a huge amount of calculation, but also requires a large amount of data collection to ensure the measurement accuracy of the power fundamental wave voltage, resulting in a large delay problem. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an ATSE power supply fundamental voltage calculation method based on the Goertzel algorithm, which solves the problem that the existing three-phase power supply fundamental voltage calculation methods widely used in dual-power automatic transfer switch products on the market mostly adopt FFT algorithms. This method not only has a huge amount of calculation, but also requires a large amount of data collection to ensure the measurement accuracy of the power supply fundamental voltage, resulting in a large delay.

[0005] To achieve the above objectives, the present invention is implemented by the following technical solutions: A method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm comprises the following steps:

[0006] S1, data acquisition: collect AD data of the three-phase voltage of the power supply at a fixed sampling rate through the sampling circuit of the controller;

[0007] S2, parameter setting: set the initial frequency of frequency detection, the number of cycles k=1 and the number of samples per cycle N;

[0008] S3. Calculate common variables: Twiddle Factor Calculate common variables of Goertzel's algorithm;

[0009] S4, resampling operation: resampling operation is performed on each sampling point according to the set frequency;

[0010] S5, convolution operation: performing convolution operation on the resampled AD data in sequence;

[0011] S6. Calculate the amplitude-frequency information: Calculate the amplitude-frequency information Y at the target frequency of the power signal n ;

[0012] S7. Calculate the fundamental amplitude: based on Y n The real part Y n_real , further calculation yields Y n Fundamental wave amplitude information;

[0013] S8. Obtain three-phase fundamental voltage information: Calculate the fundamental amplitude information of each of the three phases respectively, analyze and process it in combination with the characteristics of the three-phase circuit, and obtain the complete fundamental voltage information of the three-phase power supply.

[0014] Preferably, the initial frequency in step S2 is 50 Hz and the sampling number N is 64.

[0015] Preferably, the resampling operation in step S4 is to convert the AD data with a fixed sampling rate according to a set frequency.

[0016] Preferably, the convolution operation in step S5 is

[0017] Preferably, in step S6

[0018] Preferably, the fundamental amplitude information in step S7 is Y n_RMS =|Y n_real |.

[0019] Preferably, the Q kn is the value at time n.

[0020] The present invention provides a method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm.

[0021] Beneficial effects:

[0022] 1. In the present invention, the Goertzel algorithm is used, which regards the discrete Fourier transform as a group of filters, and uses the periodicity of the rotation factor to convert the discrete Fourier transform into a linear filtering operation, and only performs amplitude calculation on known individual frequency points. The algorithm itself discards the high-order harmonic content, reduces unnecessary calculation amount in the calculation process, simplifies the calculation process, and ensures the rapidity of the algorithm, thereby improving the existing three-phase power fundamental wave calculation method widely used in dual power automatic transfer switch products on the market. Most of them use the FFT algorithm. This method not only has a huge amount of calculation, but also requires a large amount of data collection to ensure the measurement accuracy of the power supply fundamental wave voltage, resulting in a large delay problem.

[0023] 2. In the present invention, it is only necessary to collect the AD value of the three-phase power supply to implement the entire calculation method. There is no need to add additional complex hardware circuits. The existing sampling circuit of the controller is directly used to collect the three-phase voltage AD data. After collecting at a fixed sampling rate, it is calculated through a series of software algorithms, which greatly saves the cost and complexity of the hardware circuit, and contributes to the miniaturization and cost control of the product.

[0024] 3. In the present invention, the automatic transfer switch is helped to accurately calculate the fundamental voltage information of the current power supply, including the fundamental amplitude of each of the three phases, etc., so as to better analyze the power supply status, improve the accuracy and rapidity of the dual power automatic transfer switch in judging power supply failure, and enhance the reliability of the product. At the same time, the method can be used for product upgrades at no cost, and only the software algorithm needs to be updated, which makes it convenient for the product to adapt to changes in the power system in different application scenarios and improve the overall performance and market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a circuit connection schematic diagram of the present invention;

[0026] Figure 2 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Please see attached Figure 1 The embodiment of the present invention provides a method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm, which is characterized by comprising the following steps:

[0029] S1, data acquisition: collect AD data of the three-phase voltage of the power supply at a fixed sampling rate through the sampling circuit of the controller;

[0030] S2, parameter setting: set the initial frequency of frequency detection, the number of cycles k=1 and the number of samples per cycle N;

[0031] S3. Calculate common variables: Twiddle Factor Calculate common variables of Goertzel's algorithm;

[0032] S4, resampling operation: resampling operation is performed on each sampling point according to the set frequency;

[0033] S5, convolution operation: performing convolution operation on the resampled AD data in sequence;

[0034] S6. Calculate the amplitude-frequency information: Calculate the amplitude-frequency information Y at the target frequency of the power signal n ;

[0035] S7. Calculate the fundamental amplitude: based on Y n The real part Y n_real , further calculation yields Y n Fundamental wave amplitude information;

[0036] S8. Obtain three-phase fundamental voltage information: Calculate the fundamental amplitude information of each of the three phases respectively, analyze and process it in combination with the characteristics of the three-phase circuit, and obtain the complete fundamental voltage information of the three-phase power supply.

[0037] Specifically, the AD data of the three-phase voltage of the power supply is collected at a fixed sampling rate through the sampling circuit of the controller, which can provide the original data basis for the subsequent calculation of the fundamental voltage of the three-phase power supply based on the Goertzel algorithm, so as to accurately analyze the frequency domain information of the power supply. By setting the initial frequency of the frequency detection, the number of cycles k=1 and the number of samples N in each cycle, it can ensure that the sampling data is complete within a certain frequency range, and provide the necessary parameter conditions for the subsequent accurate calculation of the relevant variables of the Goertzel algorithm and the accurate fundamental voltage calculation. By calculating the common variables of the Goertzel algorithm, it can provide the relevant conditions for the subsequent use of the Goertzel algorithm to perform convolution operations on the resampled AD data and further calculate the amplitude-frequency information at the target frequency. The calculation parameters of the key are used to accurately calculate the fundamental voltage of the three-phase power supply. By resampling each sampling point according to the set frequency, the number of sampling points in one cycle can be guaranteed to remain unchanged, so that the data meets the calculation requirements of the Goertzel algorithm, thereby providing a stable and appropriate data basis for the subsequent accurate calculation of the fundamental voltage of the three-phase power supply. By performing convolution operations on the resampled AD data in turn, the Goertzel algorithm can be used to process the input signal and the impulse response in the filter, laying a calculation foundation for the subsequent calculation of the amplitude-frequency information at the target frequency and then obtaining the fundamental voltage of the three-phase power supply, promoting the calculation process to gradually obtain accurate results, and calculating the amplitude-frequency information Y at the target frequency of the power signal. n , can obtain the frequency domain characteristics of the three-phase power supply at the target frequency point, provide key intermediate data for further calculation of the fundamental amplitude information to obtain the three-phase power supply fundamental voltage, and help to accurately analyze the power supply status. n The real part Y n_real By calculating the fundamental amplitude information, the key data of the fundamental part can be extracted from the amplitude-frequency information at the target frequency, so as to accurately obtain the fundamental voltage of the three-phase power supply, provide an accurate basis for the dual power automatic transfer switch to analyze the power supply status, and improve the rapidity and reliability of the switch control. By calculating the fundamental amplitude information of each phase and combining the three-phase circuit characteristics to obtain the complete fundamental voltage information of the three-phase power supply, the dual power automatic transfer switch can fully and accurately grasp the three-phase power supply status and provide key data support, so as to achieve effective analysis of power supply failures, ensure the rapidity and reliability of switch control and the stable operation of the entire power system;

[0038] This method is applied to Schneider Wango H-Plus controller, which can meet the reliable detection of power supply fundamental voltage without adding additional hardware circuits, improve product speed and reliability, and shorten product development cycle;

[0039] It can be implemented by only collecting the AD value of the three-phase power supply, which greatly saves the cost and complexity of the hardware circuit, helps the automatic transfer switch calculate the frequency of the current power supply, and further improves the speed and reliability of the dual power automatic transfer switch. In addition, this method can be used for product upgrades at no cost, and only the software method needs to be updated;

[0040] The entire calculation method can be implemented by only collecting the AD value of the three-phase power supply, without adding additional complex hardware circuits. The existing sampling circuit of the controller is directly used to collect the three-phase voltage AD data. After collecting at a fixed sampling rate, it is calculated through a series of software algorithms, which greatly saves the cost and complexity of the hardware circuit and helps miniaturization and cost control of the product.

[0041] It helps the automatic transfer switch to accurately calculate the fundamental voltage information of the current power supply, including the fundamental amplitude of each of the three phases, so as to better analyze the power supply status, improve the accuracy and speed of the dual power automatic transfer switch in judging power supply failures, and enhance the reliability of the product. At the same time, this method can be used for product upgrades at no cost. Only the software algorithm needs to be updated, which makes it easier for the product to adapt to changes in the power system in different application scenarios and improve the overall performance and market competitiveness of the product.

[0042] The initial frequency in step S2 is 50 Hz and the sampling number N is 64.

[0043] Specifically, by setting the initial frequency to 50 Hz and determining the sampling number N to 64, it is possible to ensure the integrity of the sampling data within the 70 Hz frequency range while providing adaptive basic parameters for the subsequent calculation of the three-phase power supply fundamental voltage based on the Goertzel algorithm, thereby ensuring the accuracy and effectiveness of the calculation.

[0044] The resampling operation in step S4 is to convert the AD data with a fixed sampling rate according to a set frequency.

[0045] Specifically, by converting the AD data with a fixed sampling rate according to the set frequency through the resampling operation in step S4, the data can be redistributed on a time scale, ensuring that the number of sampling points is constant within a cycle, thereby adapting to the calculation requirements of the Goertzel algorithm and providing a unified data basis for the subsequent accurate calculation of the fundamental voltage of the three-phase power supply.

[0046] The convolution operation in step S5 is

[0047] Specifically, through.

[0048] In step S6

[0049] Specifically, the convolution operation formula in step S5 is used in a specific calculation method to associate and process the current sampling point data with the previous sampling point data and the input signal using the Goertzel algorithm, and the intermediate results are calculated step by step and iteratively, laying a key calculation foundation for the subsequent accurate acquisition of the frequency domain information of the three-phase power supply at the target frequency point and then calculating the fundamental voltage.

[0050] The fundamental amplitude information in step S7 is Y n_RMS =|Y n_real |.

[0051] Specifically, in step S7, Y n_RMS =|Y n_real |Calculate the fundamental amplitude information, which can be obtained from Y containing the amplitude-frequency information at the target frequency n The real part of the fundamental wave amplitude is accurately extracted, thereby providing key data for obtaining the fundamental wave voltage of the three-phase power supply, and helping the dual power supply automatic transfer switch to accurately analyze and control the power supply status.

[0052] Q kn is the value at time n.

[0053] Specifically, this setting provides a basis and foundation for the iterative calculation of the Goertzel algorithm, enabling the algorithm to perform calculations and update data based on the values ​​at the current moment and the previous moment, thereby gradually deriving the information required for accurate calculation of the three-phase power supply fundamental voltage and realizing effective analysis of the power supply frequency domain information.

[0054] The Goertzel algorithm is an algorithm for calculating the discrete Fourier transform (DFT). The algorithm regards the discrete Fourier transform as a set of filters, performs convolution operations on the input signal and the impulse response in the filter, obtains the output of the filter, and obtains the frequency of a certain point in the frequency domain. The algorithm uses the periodicity of the rotation factor to convert the discrete Fourier transform into a linear filtering operation. The Goertzel algorithm only calculates the amplitude of individual known frequency points. The concept of "frequency point" is essentially the same as the frequency point in the Fourier transform, and the resolution and corresponding relationship of frequency recognition are also the same.

[0055] The detailed calculation process of the algorithm is as follows:

[0056] Define Q kn is the value at time n, but Q is needed k(n_1) and Q k(n_2) It can be seen that this algorithm is continuously iteratively calculated.

[0057] At n = 0, Q k(n_1) Q k(_1) and Q k(_2) The initial value of both is 0.

[0058] Then use the second formula to calculate the value range of n, which is 0 to N.

[0059] Get Q kn After that, add a step of sequence position exchange. Specifically: Q k(n_2) =Q k(n_1) , Q k(n_1) =Q kn , then we can proceed to the next step of calculation, which is the calculation at time n+1.

[0060] After the Goertzel algorithm, the three-phase power supply can be obtained at the target frequency F last Frequency domain information, target frequency F last The real part of the frequency domain information contains the amplitude information of the signal source. Then, the fundamental amplitude of the signal, that is, the fundamental voltage, can be obtained by modulating the real part of the calculation result.

[0061] Through the Goertzel algorithm, the algorithm regards the discrete Fourier transform as a group of filters, and uses the periodicity of the rotation factor to convert the discrete Fourier transform into a linear filtering operation. It only calculates the amplitude of known individual frequency points. The algorithm itself discards the high-order harmonic content, reduces unnecessary calculations in the calculation process, simplifies the calculation process, and ensures the speed of the algorithm, thereby improving the efficiency of the dual power supply automatic transfer switch in calculating and analyzing the power supply fundamental voltage.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm, characterized in that: The following steps are involved: S1, data acquisition: collect AD data of the three-phase voltage of the power supply at a fixed sampling rate through the sampling circuit of the controller; S2, parameter setting: set the initial frequency of frequency detection, the number of cycles k=1 and the number of samples per cycle N; S3. Calculate common variables: Twiddle Factor Calculate common variables of Goertzel's algorithm; S4, resampling operation: resampling operation is performed on each sampling point according to the set frequency; S5, convolution operation: performing convolution operation on the resampled AD data in sequence; S6. Calculate the amplitude-frequency information: Calculate the amplitude-frequency information Y at the target frequency of the power signal n ; S7. Calculate the fundamental amplitude: based on Y n The real part Y n_real , further calculation yields Y n Fundamental wave amplitude information; S8. Obtain three-phase fundamental voltage information: Calculate the fundamental amplitude information of each of the three phases respectively, analyze and process it in combination with the characteristics of the three-phase circuit, and obtain the complete fundamental voltage information of the three-phase power supply.

2. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 1, characterized in that: The initial frequency in step S2 is 50 Hz, and the sampling number N is 64.

3. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 1, characterized in that: The resampling operation in step S4 is to convert the AD data with a fixed sampling rate according to a set frequency.

4. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 1, characterized in that: The convolution operation in step S5 is:

5. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 1, characterized in that: In step S6 6. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 1, characterized in that: The fundamental amplitude information in step S7 is Y n_RMS =|Y n_real |.

7. The method for calculating the fundamental voltage of an ATSE power supply based on the Goertzel algorithm according to claim 4, characterized in that: The Q kn is the value at time n.

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