New energy primary frequency modulation frequency rapid calculation method and device based on HERMITE interpolation

Abstract

The invention provides a new energy primary frequency modulation frequency rapid calculation method and device based on HERMITE interpolation, and the method comprises the steps: collecting a three-phase voltage / current signal converted by a secondary side voltage / current transformer of a power grid in a primary frequency modulation system of a new energy station, and carrying out the digital filtering through a Butterworth band-pass filter; selecting four pieces of sampling data near a zero crossing point of the voltage / current signal after digital filtering, and constructing a four-point HERMITE interpolation polynomial; and calculating the new energy primary frequency modulation frequency according to the zero crossing point of the interpolation polynomial. The error of the method is obviously smaller than that of a traditional method, and good precision can still be kept when noise is large.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy power, and in particular relates to a method and device for quickly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation. Background Art

[0002] In the primary frequency modulation system of new energy stations, accurate estimation of the grid frequency is the key to ensure system stability and efficiency. The sampling frequency of the power acquisition module of the general power system is below 9600Hz, and the grid frequency is mainly in the range of 45-55Hz. The current national standard for the frequency acquisition accuracy and rate of new energy primary frequency modulation and inertia response system are: 0.001Hz, 10ms; the primary frequency modulation system of new energy stations requires the frequency of the signal to be calculated within 100ms, with an accuracy of 0.001Hz.

[0003] Currently, the commonly used methods include Fast Fourier Transform (FFT) and zero-crossing detection, but both methods have some shortcomings.

[0004] The disadvantages of the Fast Fourier Transform (FFT) method are: The frequency resolution of FFT is limited by the sampling rate and signal length. If the frequency is solved using the Fast Fourier Transform, the frequency resolution is: Δf = 1 / T, where T is the total time length of the signal, that is, when the frequency accuracy requirement is 0.001 Hz, a 1000-second signal is required, which does not meet the 10 ms requirement.

[0005] The disadvantage of the zero-crossing detection method is that it is sensitive to noise and difficult to effectively filter out the influence of noise. If the noise is large, it is difficult to meet the high-precision requirements. Summary of the invention

[0006] The present invention proposes a method and device for quickly calculating the primary frequency modulation frequency of a new energy source based on HERMITE interpolation, which is based on traditional zero-crossing point detection and can achieve good accuracy even when the noise is large.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows: A fast calculation method for the primary frequency modulation of new energy based on HERMITE interpolation, including: In the primary frequency modulation system of the new energy station, the three-phase voltage / current signals converted by the voltage / current transformer on the secondary side of the power grid are collected and digitally filtered using a Butterworth bandpass filter. Four sampling data are selected near the zero-crossing point of the voltage / current signal after digital filtering to construct a four-point HERMITE interpolation polynomial. The primary frequency modulation frequency of the new energy is calculated based on the zero-crossing point of the interpolation polynomial.

[0008] Furthermore, it also includes: after calculating the signal frequency, verifying the frequency validity.

[0009] Further, the method of digital filtering using a Butterworth bandpass filter includes: S101, setting initial filter parameters: the filter order is set to 4th order, and the coefficients of the 4th order numerator polynomial b=[b0, b1, b2, b3, b4] and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4] are set; S102, setting the differential equation of the output data after filtering by the filter as follows: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

[0010] Furthermore, the method for constructing the four-point HERMITE interpolation polynomial is: Assume that the 4 sampling data are , where x represents the abscissa of the interpolation point, and y represents the function value corresponding to x; the four-point HERMITE interpolation polynomial is constructed as: ; Where H(x) represents the HERMITE interpolation polynomial; y0' is the derivative value at x0, which represents the slope of the function at that point; y1' is the derivative value at x1, which represents the slope of the function at that point; y2' is the derivative value at x2, which represents the slope of the function at that point; y3' is the derivative value at x3, which represents the slope of the function at that point.

[0011] Furthermore, the method for calculating the primary frequency modulation frequency of the renewable energy source according to the zero-crossing point of the interpolation polynomial includes: Find two values ​​near the interpolated zero point and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculationi-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3; get the primary frequency modulation frequency f of the new energy.

[0012] On the other hand, the present invention also proposes a new energy primary frequency modulation fast calculation device based on HERMITE interpolation, comprising: Acquisition and filtering module: In the primary frequency modulation system of the new energy station, the three-phase voltage / current signal after the voltage / current transformer conversion on the secondary side of the power grid is collected and digitally filtered using a Butterworth bandpass filter; Sampling construction module: Select 4 sampling data near the zero-crossing point of the voltage / current signal after digital filtering to construct a four-point HERMITE interpolation polynomial; Calculation module: Calculate the primary frequency modulation frequency of the new energy according to the zero-crossing point of the interpolation polynomial.

[0013] Furthermore, it also includes a verification module: after calculating the signal frequency, the frequency validity is verified.

[0014] Furthermore, the acquisition and filtering module includes: Parameter setting unit: set the initial parameters of the filter, set the filter order to 4th order, and set the coefficients of the numerator polynomial of the 4th order b=[b0, b1, b2, b3, b4] and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4]; Difference equation unit: The difference equation of the output data after setting the filter is as follows: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

[0015] Furthermore, the sampling construction module includes: Assume that the 4 sampling data are , where x represents the abscissa of the interpolation point, and y represents the function value corresponding to x; the four-point HERMITE interpolation polynomial is constructed as: ; Where H(x) represents the HERMITE interpolation polynomial; y0' is the derivative value at x0, which represents the slope of the function at that point; y1' is the derivative value at x1, which represents the slope of the function at that point; y2' is the derivative value at x2, which represents the slope of the function at that point; y3' is the derivative value at x3, which represents the slope of the function at that point.

[0016] Furthermore, the calculation module includes: Find two values ​​near the interpolated zero point and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculation i-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3; get the primary frequency modulation frequency f of the new energy.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Improved accuracy: The error of the HERMITE interpolation method used in the present invention is significantly smaller than that of the traditional method, and it can still maintain good accuracy when the noise is large.

[0018] 2. Strong anti-interference ability: The present invention utilizes derivative information to improve the accuracy of signal reconstruction and has a smoothing effect on the noise near the sampling point.

[0019] 3. High computational efficiency: The present invention only requires a small number of sampling points near the zero-crossing point, with a moderate amount of computation, and is suitable for real-time processing.

[0020] 4. Good adaptability: The present invention has good adaptability to signal distortion and can handle the situation of non-uniform sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the process of Example 1 of the present invention.

[0022] Figure 2 It is a comparison diagram of the traditional linear interpolation zero-crossing point and the HERMITE interpolation zero-crossing point of Example 1 of the present invention. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] In order to make the purpose and features of the present invention more obvious and understandable, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] Embodiment 1: Based on the traditional zero-crossing detection, this embodiment uses the HERMITE interpolation method to make a more precise difference in the data near the signal zero point, thereby improving the detection accuracy when the sampling frequency is not high enough. The specific steps are as follows Figure 1 As shown, including: Step 1: Signal acquisition.

[0026] In the primary frequency modulation system of the new energy station, the three-phase circuit voltage / current signal after conversion by the voltage / current transformer on the secondary side of the power grid is collected. The sampling frequency is 9600Hz, and the power grid frequency is 50Hz, that is, the number of sampling points per power frequency cycle is: 9600 / 50=192 points; it is converted into a digital signal through an AC / DC converter.

[0027] Step 2: Digital filtering.

[0028] The Butterworth bandpass filter is used for digital filtering to filter out high and low frequency disturbance signals other than 45~55Hz. The advantages are: Flat passband: The frequency response of the Butterworth filter within the passband is very flat and has no ripples, which enables it to effectively preserve the amplitude characteristics of the signal within the passband.

[0029] Gradual Attenuation: After the cutoff frequency, the Butterworth filter has a very smooth attenuation, avoiding sharp changes in the frequency response.

[0030] Here’s how: 1. Set the initial filter parameters: Low cut-off frequency f1 = 45 Hz; High cut-off frequency f2 = 55Hz; Sampling frequency f s =9600Hz; The filter order is 4; Low cut-off frequency ; High cut-off frequency ; The fourth-order parameters are: the coefficients of the numerator polynomial b=[b0, b1, b2, b3, b4], and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4]; In this embodiment, the cutoff frequency is brought in and solved using the Python Scipy library to obtain the specific values ​​of each coefficient, which can be used directly: The coefficient of the numerator polynomial is b=[0.0099,0,-0.0198,0,0.0099]; The coefficient of the denominator polynomial a=[1.0000,-3.9155,5.7472,-3.7638,0.9321]; 2. Set the differential equation for the filtered output data: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; According to the specific values ​​of the above coefficients, the differential equation of the output data after filtering can be obtained as follows: y[n]=0.0099x[n]-0.0198x[n-2]+0.0099x[n-4]+3.9155y[n-1]-5.7472y[n-2]+3.7638y[n-3]-0.9321y[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

[0031] Step 3: Interpolate the data near the signal zero point.

[0032] Select 4 sampling data near the zero-crossing point, 2 before and after zero; Among them, the HERMITE interpolation polynomial is a polynomial used to construct a polynomial passing through given data points. It not only considers the value of the data point (function value), but also the derivative value (slope) of these points. In HERMITE interpolation, the sampling points are usually represented as a set of points (x i , y i ),in: x i , is the horizontal coordinate (independent variable) of the interpolation point.

[0033] y i is the value corresponding to x i The function value (dependent variable), that is, y i =f(x i ).

[0034] The specific steps of calculating the derivative using the central difference method and constructing the HERMITE interpolation polynomial are as follows: The four sampling points are (x i ,y i), i=0,1,...,3, we want to calculate the derivative at a certain point x.

[0035] HERMITE interpolation polynomial construction process: Basic function definition: α j (x)=[1-2(xx j )L' j (x j )]L j ²(x); β j (x)=(xx j )L j ²(x); L j (x) is the Lagrange basic polynomial: L j (x)=∏(k≠j)(x k ) / (x j -x k ); L' j (x j ) is L j (x) at node x j The derivative at a point represents the slope or rate of change at that point; j is the index of the Lagrangian basis polynomial currently being constructed. It represents the specific node (or data point) of interest during the interpolation process. In the interpolation polynomial, L j (x) is used to ensure that the interpolation polynomial is at node x j The value at x is 1, and at all other nodes x k The value at (k≠j) is 0.

[0036] k is the index used to loop through all interpolation nodes, representing the index of other nodes, and the value range of k is from 0 to n (the total number of interpolation nodes), but excludes the current j value. In other words, k represents all nodes that are different from j.

[0037] α j (x): Usually represents the HERMITE basis function, which is used for interpolation. Its function is to ensure that the interpolation polynomial is at each sampling point x j The function value f(x j ) are correctly reflected.

[0038] β j (x): Usually represents the derivative part of the HERMITE basis function, which is used for the derivative value of the interpolation. Its role is to ensure that the interpolation polynomial is at each sampling point x j The derivative value f'(x j ) are correctly reflected.

[0039] The complete form of the HERMITE interpolation polynomial is: H(x)=Σ[f(x j )α j (x)+f'(x j )β j (x)]; Specific formula derivation: For 4 sampling points , the HERMITE interpolation polynomial is constructed as follows: H(x)=y0h0(x)+y1h1(x)+y2h2(x)+y3h3(x)+y0'H0(x)+y1'H1(x)+y1'H2(x)+y3'H3(x); y0' is the derivative value at the node x0, which represents the slope of the function at that point.

[0040] y1' is the derivative value at node x1, which represents the slope of the function at that point.

[0041] Y2' is the derivative value at node x2, which represents the slope of the function at that point.

[0042] y3' is the derivative value at node x3, which represents the slope of the function at that point.

[0043] Basis function calculation: a)L i (x): Lagrange basic polynomial; L0(x)=(x-x1)(x-x2)(x-x3) / [(x0-x1)(x0-x2)(x0-x3)]; L1(x)=(x-x0)(x-x2)(x-x3) / [(x1-x0)(x1-x2)(x1-x3)]; L2(x)=(x-x0)(x-x1)(x-x3) / [(x2-x0)(x2-x1)(x2-x3)]; L3(x)=(x-x0)(x-x1)(x-x2) / [(x3-x0)(x3-x1)(x3-x2)]; b)h i (x): HERMITE basis function: h0(x)=[1-2(x-x0) L0'(x0)]L0²(x); h1(x)=[1-2(x-x1) L1'(x1)]L1²(x); h2(x)=[1-2(x-x2) L2'(x2)]L2²(x); h3(x)=[1-2(x-x3) L3'(x3)]L3²(x); L0'(x0), L1'(x1), L2'(x2), L3'(x3): represent the derivative values ​​of Lagrange basic polynomial L0(x) at node x0, L1(x) at node x1, L2(x) at node x2, L3(x) at node x3, respectively, reflecting the rate of change or slope of the interpolation polynomial at that point.

[0044] c)H i (x): basis functions related to derivatives; H0(x)=(x-x0)L0²(x); H1(x)=(x-x1)L1²(x); H2(x)=(x-x2)L2²(x); H3(x)=(x-x3)L3²(x); A simplified form for equally spaced sampling points: Assume that the sampling interval is h, that is, x i+1 -x i =h, the derivative calculation formula at point x1 can be simplified to: f'(x1)≈[y0-8y1+8y2-y3] / (12h)+O(h 4 ); The final four-point HERMITE interpolation polynomial: ; Step 4: Calculate the primary frequency modulation frequency of the renewable energy source according to the zero-crossing point of the interpolation polynomial.

[0045] Find two values ​​near 0 of the interpolated data and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculation i-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3.

[0046] Step 5: Frequency validity check.

[0047] If the calculated f is greater than 55Hz or less than 45Hz, the current calculation is invalid and the previous calculation result is retained.

[0048] By implementing the above method, assuming that the true frequency is 50.2Hz, the accuracy calculation results under different noise levels are as follows:

[0049] Among them, the zero-crossing point found by traditional linear interpolation is compared with the zero-crossing point found by HERMITE interpolation. Figure 2 shown.

[0050] It can be seen that the error of the HERMITE interpolation method proposed in this embodiment is significantly smaller than that of the traditional method, and it can still maintain good accuracy when the noise is large.

[0051] Embodiment 2: In this embodiment 2, a device for quickly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation is proposed, comprising: Acquisition and filtering module: In the primary frequency modulation system of the new energy station, the three-phase voltage / current signal after the voltage / current transformer conversion on the secondary side of the power grid is collected and digitally filtered using a Butterworth bandpass filter; Sampling construction module: Select 4 sampling data near the zero-crossing point of the voltage / current signal after digital filtering to construct a four-point HERMITE interpolation polynomial; Calculation module: calculate the primary frequency modulation frequency of renewable energy according to the zero-crossing point of the interpolation polynomial; Verification module: After calculating the signal frequency, the frequency validity is verified.

[0052] Wherein, the acquisition and filtering module includes: Parameter setting unit: set the initial parameters of the filter, set the filter order to 4th order, and set the coefficients of the numerator polynomial of the 4th order b=[b0, b1, b2, b3, b4] and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4]; Difference equation unit: The difference equation of the output data after setting the filter is as follows: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

[0053] Wherein, the sampling construction module includes: Assume that the 4 sampling data are , where x represents the abscissa of the interpolation point, and y represents the function value corresponding to x; the four-point HERMITE interpolation polynomial is constructed as: ; Where H(x) represents the HERMITE interpolation polynomial; y0' is the derivative value at x0, which represents the slope of the function at that point; y1' is the derivative value at x1, which represents the slope of the function at that point; y2' is the derivative value at x2, which represents the slope of the function at that point; y3' is the derivative value at x3, which represents the slope of the function at that point.

[0054] Wherein, the calculation module includes: Find two values ​​near the interpolated zero point and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculation i-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3; get the primary frequency modulation frequency f of the new energy.

[0055] The device for quickly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation proposed in this embodiment 2 can realize the method for quickly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation described in embodiment 1, and has the same technical effect as embodiment 1.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fast calculation method for the primary frequency modulation of new energy based on HERMITE interpolation, characterized in that: include: In the primary frequency modulation system of the new energy station, the three-phase voltage / current signals converted by the voltage / current transformer on the secondary side of the power grid are collected and digitally filtered using a Butterworth bandpass filter. Four sampling data are selected near the zero-crossing point of the voltage / current signal after digital filtering to construct a four-point HERMITE interpolation polynomial. The primary frequency modulation frequency of the new energy is calculated based on the zero-crossing point of the interpolation polynomial.

2. The method for rapidly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation according to claim 1 is characterized in that: Also includes: After calculating the signal frequency, the frequency validity is verified.

3. The method for rapidly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation according to claim 1 is characterized in that: The method for digital filtering using a Butterworth bandpass filter comprises: S101, setting initial filter parameters: the filter order is set to 4th order, and the coefficients of the 4th order numerator polynomial b=[b0, b1, b2, b3, b4] and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4] are set; S102, setting the differential equation of the output data after filtering by the filter as follows: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

4. The method for rapidly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation according to claim 1 is characterized in that: The method for constructing the four-point HERMITE interpolation polynomial is: Assume that the 4 sampling data are , where x represents the abscissa of the interpolation point, and y represents the function value corresponding to x; the four-point HERMITE interpolation polynomial is constructed as: ； Where H(x) represents the HERMITE interpolation polynomial; y0' is the derivative value at x0, which represents the slope of the function at that point; y1' is the derivative value at x1, which indicates the slope of the function at that point; y2' is the derivative value at x2, which represents the slope of the function at that point; y3' is the derivative value at x3, which represents the slope of the function at that point.

5. The method for rapidly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation according to claim 1 is characterized in that: The method for calculating the primary frequency modulation frequency of renewable energy based on the zero-crossing point of the interpolation polynomial includes: Find two values ​​near the interpolated zero point and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculation i-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3; get the primary frequency modulation frequency f of the new energy.

6. A fast calculation device for primary frequency modulation of new energy based on HERMITE interpolation, characterized in that: include: Acquisition and filtering module: In the primary frequency modulation system of the new energy station, the three-phase voltage / current signal after the voltage / current transformer conversion on the secondary side of the power grid is collected and digitally filtered using a Butterworth bandpass filter; Sampling construction module: Select 4 sampling data near the zero-crossing point of the voltage / current signal after digital filtering to construct a four-point HERMITE interpolation polynomial; Calculation module: Calculate the primary frequency modulation frequency of the new energy according to the zero-crossing point of the interpolation polynomial.

7. The device for rapidly calculating the primary frequency modulation of new energy based on HERMITE interpolation according to claim 6 is characterized in that: It also includes a verification module: after calculating the signal frequency, the frequency validity verification is performed.

8. The device for rapidly calculating the primary frequency modulation of new energy based on HERMITE interpolation according to claim 6 is characterized in that: The acquisition and filtering module comprises: Parameter setting unit: set the initial parameters of the filter, set the filter order to 4th order, and set the coefficients of the numerator polynomial of the 4th order b=[b0, b1, b2, b3, b4] and the coefficients of the denominator polynomial a=[a0, a1, a2, a3, a4]; Difference equation unit: The difference equation of the output data after setting the filter is as follows: a0*y[n]+a1*y[n-1]+a2*y[n-2]+a3*y[n-3]+a4*y[n-4]=b0*x[n]+b1*x[n-1]+b2*x[n-2]+b3*x[n-3]+b4*x[n-4]; Among them, n is the time sequence of the current input signal; y[n]: the value of the filter output signal at time sequence n; x[n]: The value of the filter's input signal at time sequence n.

9. The device for rapidly calculating the primary frequency modulation frequency of new energy based on HERMITE interpolation according to claim 6 is characterized in that: The sampling building block includes: Assume that the 4 sampling data are , where x represents the abscissa of the interpolation point, and y represents the function value corresponding to x; the four-point HERMITE interpolation polynomial is constructed as: ； Where H(x) represents the HERMITE interpolation polynomial; y0' is the derivative value at x0, which represents the slope of the function at that point; y1' is the derivative value at x1, which indicates the slope of the function at that point; y2' is the derivative value at x2, which represents the slope of the function at that point; y3' is the derivative value at x3, which represents the slope of the function at that point.

10. The device for rapidly calculating the primary frequency modulation of new energy based on HERMITE interpolation according to claim 6 is characterized in that: The calculation module comprises: Find two values ​​near the interpolated zero point and average their time coordinates as t i ; i is the i-th zero-crossing point; and the last found zero crossing point t i-1 The time difference between i -t i-1 ; The frequency f of the signal after this calculation i-1 =1 / 2T; Then smooth the result f=(f i-1 +f i-2 +f i-3 ) / 3; get the primary frequency modulation frequency f of the new energy.

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