CN104678170A - Power harmonic analysis method based on harmonic analyzer and harmonic analyzer - Google Patents

Power harmonic analysis method based on harmonic analyzer and harmonic analyzer Download PDF

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CN104678170A
CN104678170A CN201310641539.0A CN201310641539A CN104678170A CN 104678170 A CN104678170 A CN 104678170A CN 201310641539 A CN201310641539 A CN 201310641539A CN 104678170 A CN104678170 A CN 104678170A
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李涛
刘瑞
徐鲲鹏
皮学军
贾伟
亓学庆
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State Grid Corp of China SGCC
Beijing Nanrui Zhixin Micro Electronics Technology Co Ltd
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Abstract

本发明公开了一种基于谐波分析仪的电力谐波分析方法和谐波分析仪,其中,该方法包括:确定预设基频,根据预设基频为输入信号设计第一FIR梳状滤波器;通过第一FIR梳状滤波器对输入信号进行滤波,并确定滤波后信号的频率;当滤波后信号的频率与预设基频之间的差值小于预设阈值时,将滤波后信号的频率作为输入信号的基频;根据基频确定谐波的频率,并为谐波设计第二FIR梳状滤波器;通过第二FIR梳状滤波器对输入信号进行滤波,确定谐波的信号参数,并将信号参数发送给谐波分析仪的处理单元。该电力谐波分析方法很容易实现,可以方便计算出谐波参数,精度高,且该方法不受频率漂移影响。

The invention discloses a power harmonic analysis method based on a harmonic analyzer and a harmonic analyzer, wherein the method includes: determining a preset fundamental frequency, and designing a first FIR comb filter for an input signal according to the preset fundamental frequency filter; filter the input signal through the first FIR comb filter, and determine the frequency of the filtered signal; when the difference between the frequency of the filtered signal and the preset base frequency is less than the preset threshold, the filtered signal The frequency of the input signal is used as the fundamental frequency of the input signal; the frequency of the harmonic is determined according to the fundamental frequency, and a second FIR comb filter is designed for the harmonic; the input signal is filtered through the second FIR comb filter to determine the signal of the harmonic parameters, and send the signal parameters to the processing unit of the harmonic analyzer. The power harmonic analysis method is easy to implement, can conveniently calculate harmonic parameters, has high precision, and is not affected by frequency drift.

Description

一种基于谐波分析仪的电力谐波分析方法和谐波分析仪A kind of electric harmonic analysis method and harmonic analyzer based on harmonic analyzer

技术领域technical field

本发明涉及信号处理技术领域,具体地,涉及一种基于谐波分析仪的电力谐波分析方法和谐波分析仪。The present invention relates to the technical field of signal processing, in particular to a harmonic analyzer-based power harmonic analysis method and a harmonic analyzer.

背景技术Background technique

随着电力电子技术的快速发展,电力系统的谐波污染日益严重,电力电子装置带来的谐波问题对电力系统安全、稳定、经济运行构成潜在威胁,给周围电气环境带来了极大影响,电能质量问题受到高度重视,谐波分析技术在电能质量监控、电子产品生产检验、电器设备监控等众多领域应用广泛,是进行电网监控、质量检验、设备监控的重要技术手段。目前常用的分析方法主要有离散傅里叶变换(DFT)、快速傅里叶变换(FFT)、基于FIR(Finite Impulse Response,有限冲击响应)数字滤波算法、小波变换法和Prony算法等。With the rapid development of power electronic technology, the harmonic pollution of the power system is becoming more and more serious. The harmonic problems brought by power electronic devices pose a potential threat to the safety, stability and economic operation of the power system, and have a great impact on the surrounding electrical environment. , the problem of power quality has been highly valued. Harmonic analysis technology is widely used in many fields such as power quality monitoring, electronic product production inspection, and electrical equipment monitoring. It is an important technical means for power grid monitoring, quality inspection, and equipment monitoring. At present, the commonly used analysis methods mainly include discrete Fourier transform (DFT), fast Fourier transform (FFT), digital filtering algorithm based on FIR (Finite Impulse Response, finite impulse response), wavelet transform method and Prony algorithm, etc.

在工程应用中,谐波分析总是进行有限点的采样,难以做到严格意义的同步采样。这样,在应用FFT、DFT进行谐波分析时,就会存在由于截断效应导致的长范围泄漏和由于栅栏效应导致的短范围泄漏,使得分析结果精度不高,甚至不可信。In engineering applications, harmonic analysis always performs sampling at limited points, and it is difficult to achieve strict synchronous sampling. In this way, when FFT and DFT are used for harmonic analysis, there will be long-range leakage due to the truncation effect and short-range leakage due to the fence effect, making the analysis results inaccurate or even unreliable.

基于FIR数字滤波器的电力系统各次谐波分析是这些方法中原理简单且较为有效的一种算法。FIR数字滤波器可以从信号中过滤出所需的频率分量,但这种方法存在一些副作用,它改变了信号中剩余频率分量的幅度和相位。The harmonic analysis of power system based on FIR digital filter is a simple and effective algorithm among these methods. FIR digital filters can filter out the desired frequency components from a signal, but this method has some side effects, it changes the amplitude and phase of the remaining frequency components in the signal.

发明内容Contents of the invention

本发明是为了克服现有技术中谐波分析时存在栅栏效应的缺陷,根据本发明的一个方面,提出一种基于谐波分析仪的电力谐波分析方法。The purpose of the present invention is to overcome the defect of fence effect in the harmonic analysis in the prior art, and according to one aspect of the present invention, a power harmonic analysis method based on a harmonic analyzer is proposed.

根据本发明实施例的一种基于谐波分析仪的电力谐波分析方法,包括:A method for analyzing power harmonics based on a harmonic analyzer according to an embodiment of the present invention, comprising:

确定预设基频,根据预设基频为输入信号设计第一FIR梳状滤波器;通过第一FIR梳状滤波器对输入信号进行滤波,并确定滤波后信号的频率;当滤波后信号的频率与预设基频之间的差值小于预设阈值时,将滤波后信号的频率作为输入信号的基频;根据基频确定谐波的频率,并为谐波设计第二FIR梳状滤波器;通过第二FIR梳状滤波器对输入信号进行滤波,确定谐波的信号参数,并将信号参数发送给谐波分析仪的处理单元,信号参数包括:信号幅值和信号相位角。Determine the preset base frequency, design the first FIR comb filter for the input signal according to the preset base frequency; filter the input signal through the first FIR comb filter, and determine the frequency of the filtered signal; when the filtered signal When the difference between the frequency and the preset fundamental frequency is less than the preset threshold, the frequency of the filtered signal is used as the fundamental frequency of the input signal; the frequency of the harmonic is determined according to the fundamental frequency, and a second FIR comb filter is designed for the harmonic The input signal is filtered by the second FIR comb filter, the signal parameters of the harmonics are determined, and the signal parameters are sent to the processing unit of the harmonic analyzer. The signal parameters include: signal amplitude and signal phase angle.

优选的,基于谐波分析仪的电力谐波分析方法还包括:当滤波后信号的频率与预设基频之间的差值不小于预设阈值时,继续通过第一FIR梳状滤波器对滤波后信号进行滤波,直至再次滤波后信号的频率与预设基频之间的差值小于预设阈值,并将再次滤波后信号的频率作为输入信号的基频。Preferably, the power harmonic analysis method based on the harmonic analyzer further includes: when the difference between the frequency of the filtered signal and the preset fundamental frequency is not less than the preset threshold, continue to pass through the first FIR comb filter pair The filtered signal is filtered until the difference between the frequency of the re-filtered signal and the preset fundamental frequency is less than a preset threshold, and the frequency of the re-filtered signal is used as the fundamental frequency of the input signal.

优选的,确定滤波后信号的频率,包括:Preferably, determining the frequency of the filtered signal includes:

获取滤波后信号的连续三次采样值x(k)、x(k+1)和x(k+2);Obtain three consecutive sampling values x(k), x(k+1) and x(k+2) of the filtered signal;

确定滤波后信号的频率为:其中Δt为采样时间间隔。Determine the frequency of the filtered signal as: in Δt is the sampling time interval.

优选的,确定谐波的信号参数,包括:Preferably, determining the signal parameters of the harmonics includes:

获取谐波的连续两次采样值xi(k)和xi(k+1);Obtain two consecutive sampling values x i (k) and x i (k+1) of the harmonic;

确定谐波的信号幅值为:Xi=2|Ai|;Determine the signal amplitude of the harmonic as: X i =2|A i |;

确定谐波的信号相位角为:φi=angle(Ai);Determine the signal phase angle of the harmonic as: φ i = angle(A i );

其中, fi为谐波的频率,Δt为采样时间间隔。in, f i is the frequency of the harmonic, and Δt is the sampling time interval.

优选的,第一FIR梳状滤波器和第二FIR梳状滤波器为FIR窗滤波器;Preferably, the first FIR comb filter and the second FIR comb filter are FIR window filters;

对于采样序列x(k)=Xcos(2πfkΔt+φ),经过FIR窗滤波器进行滤波处理后:For the sampling sequence x(k)=Xcos(2πfkΔt+φ), after filtering by FIR window filter:

x ~ ( k ) = X 2 e jφ a k Σ n = 0 M - 1 W ( n ) a n + X 2 e - jφ a - k Σ n = 0 M - 1 W ( n ) a n , 其中a=ej2πfΔt Σ n = 0 M - 1 W ( n ) a n 为窗校正因子。 x ~ ( k ) = x 2 e jφ a k Σ no = 0 m - 1 W ( no ) a no + x 2 e - jφ a - k Σ no = 0 m - 1 W ( no ) a no , where a=e j2πfΔt , Σ no = 0 m - 1 W ( no ) a no is the window correction factor.

优选的,当第二FIR梳状滤波器为FIR窗滤波器时,确定谐波的信号参数,包括:Preferably, when the second FIR comb filter is an FIR window filter, determining the signal parameters of the harmonics includes:

获取谐波的连续两次采样值 Get two consecutive samples of the harmonic and

确定谐波的信号幅值为:Xi=2|Ai|;Determine the signal amplitude of the harmonic as: X i =2|A i |;

确定谐波的信号相位角为:φi=angle(Ai);Determine the signal phase angle of the harmonic as: φ i = angle(A i );

其中, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) × WCF i , a i = e j 2 π f i Δt , WCF i = Σ n = 0 M - 1 W ( n ) a i n , fi为谐波的频率,Δt为采样时间间隔。in, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) × WCF i , a i = e j 2 π f i Δt , WCF i = Σ no = 0 m - 1 W ( no ) a i no , f i is the frequency of the harmonic, and Δt is the sampling time interval.

本发明实施例提供的一种基于谐波分析仪的电力谐波分析方法,该方法很容易实现,可以方便计算出谐波参数,精度高,且该方法不受频率漂移影响,同时采样频率不必是基波频率的2n倍,有效克服了泄露、栅栏效应和混叠效应等严重影响谐波分析精度的缺点。A power harmonic analysis method based on a harmonic analyzer provided by an embodiment of the present invention is easy to implement and can conveniently calculate harmonic parameters with high precision, and the method is not affected by frequency drift, and the sampling frequency does not need to be It is 2n times of the fundamental frequency, which effectively overcomes the shortcomings of leakage, fence effect and aliasing effect that seriously affect the accuracy of harmonic analysis.

本发明是为了克服现有技术中谐波分析时存在栅栏效应的缺陷,根据本发明的一个方面,提出一种谐波分析仪。The purpose of the present invention is to overcome the defect of fence effect in the harmonic analysis in the prior art, and according to one aspect of the present invention, a harmonic analyzer is proposed.

根据本发明实施例的谐波分析仪,包括:A harmonic analyzer according to an embodiment of the present invention includes:

第一滤波设计模块,用于确定预设基频,根据预设基频为输入信号设计第一FIR梳状滤波器;The first filtering design module is used to determine the preset fundamental frequency, and design a first FIR comb filter for the input signal according to the preset fundamental frequency;

第一滤波模块,用于通过第一FIR梳状滤波器对输入信号进行滤波,并确定滤波后信号的频率;The first filtering module is configured to filter the input signal through a first FIR comb filter, and determine the frequency of the filtered signal;

基频确定模块,用于当滤波后信号的频率与预设基频之间的差值小于预设阈值时,将滤波后信号的频率作为输入信号的基频;A base frequency determination module, configured to use the frequency of the filtered signal as the base frequency of the input signal when the difference between the frequency of the filtered signal and the preset base frequency is less than a preset threshold;

第二滤波设计模块,用于根据基频确定谐波的频率,并为谐波设计第二FIR梳状滤波器;The second filter design module is used to determine the frequency of the harmonic according to the fundamental frequency, and to design a second FIR comb filter for the harmonic;

第二滤波模块,用于通过第二FIR梳状滤波器对输入信号进行滤波,确定谐波的信号参数,并将信号参数发送给谐波分析仪的处理单元,信号参数包括:信号幅值和信号相位角。The second filter module is used to filter the input signal through the second FIR comb filter, determine the signal parameters of the harmonics, and send the signal parameters to the processing unit of the harmonic analyzer. The signal parameters include: signal amplitude and signal phase angle.

优选的,第一滤波模块还用于:当滤波后信号的频率与预设基频之间的差值不小于预设阈值时,继续通过第一FIR梳状滤波器对滤波后信号进行滤波,直至再次滤波后信号的频率与预设基频之间的差值小于预设阈值;Preferably, the first filtering module is also used for: when the difference between the frequency of the filtered signal and the preset fundamental frequency is not less than the preset threshold, continue to filter the filtered signal through the first FIR comb filter, until the difference between the frequency of the filtered signal and the preset fundamental frequency is smaller than the preset threshold;

基频确定模块还用于:将再次滤波后信号的频率作为输入信号的基频。The base frequency determining module is also used for: taking the frequency of the filtered signal as the base frequency of the input signal.

优选的,第一滤波模块包括:Preferably, the first filter module includes:

第一采集单元,用于获取滤波后信号的连续三次采样值x(k)、x(k+1)和x(k+2);The first acquisition unit is used to obtain three consecutive sampling values x(k), x(k+1) and x(k+2) of the filtered signal;

第一计算单元,用于确定滤波后信号的频率为:其中Δt为采样时间间隔。The first calculation unit is used to determine the frequency of the filtered signal as: in Δt is the sampling time interval.

优选的,第二滤波模块包括:Preferably, the second filter module includes:

第二采集单元,用于获取谐波的连续两次采样值xi(k)和xi(k+1);The second acquisition unit is used to obtain two consecutive sampling values x i (k) and x i (k+1) of the harmonic;

第二计算单元,用于确定谐波的信号幅值为:Xi=2|Ai|;确定谐波的信号相位角为:φi=angle(Ai);The second calculation unit is used to determine the signal amplitude of the harmonic: X i =2|A i |; determine the phase angle of the signal of the harmonic: φ i =angle(A i );

其中, fi为谐波的频率,Δt为采样时间间隔。in, f i is the frequency of the harmonic, and Δt is the sampling time interval.

优选的,第一滤波设计模块确定的第一FIR梳状滤波器和第二滤波设计模块确定的第二FIR梳状滤波器为FIR窗滤波器;Preferably, the first FIR comb filter determined by the first filter design module and the second FIR comb filter determined by the second filter design module are FIR window filters;

对于采样序列x(k)=Xcos(2πfkΔt+φ),经过FIR窗滤波器进行滤波处理后:For the sampling sequence x(k)=Xcos(2πfkΔt+φ), after filtering by FIR window filter:

x ~ ( k ) = X 2 e jφ a k Σ n = 0 M - 1 W ( n ) a n + X 2 e - jφ a - k Σ n = 0 M - 1 W ( n ) a n , 其中a=ej2πfΔt Σ n = 0 M - 1 W ( n ) a n 为窗校正因子。 x ~ ( k ) = x 2 e jφ a k Σ no = 0 m - 1 W ( no ) a no + x 2 e - jφ a - k Σ no = 0 m - 1 W ( no ) a no , where a=e j2πfΔt , Σ no = 0 m - 1 W ( no ) a no is the window correction factor.

优选的,当第二FIR梳状滤波器为FIR窗滤波器时,第二滤波模块包括:Preferably, when the second FIR comb filter is an FIR window filter, the second filter module includes:

第三采集单元,用于获取谐波的连续两次采样值和x The third acquisition unit is used to obtain two consecutive sampling values of harmonics and x

第三计算单元,用于确定谐波的信号幅值为:Xi=2|Ai|;确定谐波的信号相位角为:φi=angle(Ai);The third calculation unit is used to determine the signal amplitude of the harmonic: X i =2|A i |; determine the phase angle of the harmonic signal: φ i =angle(A i );

其中, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) × WCF i , a i = e j 2 π f i Δt , WCF i = Σ n = 0 M - 1 W ( n ) a i n , fi为谐波的频率,Δt为采样时间间隔。in, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) × WCF i , a i = e j 2 π f i Δt , WCF i = Σ no = 0 m - 1 W ( no ) a i no , f i is the frequency of the harmonic, and Δt is the sampling time interval.

本发明的其它特征和优点将在随后的说明书中阐述,并且,部分地从说明书中变得显而易见,或者通过实施本发明而了解。本发明的目的和其他优点可通过在所写的说明书、权利要求书、以及附图中所特别指出的结构来实现和获得。Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

下面通过附图和实施例,对本发明的技术方案做进一步的详细描述。The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

附图说明Description of drawings

附图用来提供对本发明的进一步理解,并且构成说明书的一部分,与本发明的实施例一起用于解释本发明,并不构成对本发明的限制。在附图中:The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

图1为本发明实施例中谐波分析方法的流程图;Fig. 1 is the flowchart of harmonic analysis method in the embodiment of the present invention;

图2为实施例一中谐波分析方法的流程图;Fig. 2 is the flowchart of harmonic analysis method in embodiment one;

图3为本发明实施例中谐波分析仪的结构图。Fig. 3 is a structural diagram of a harmonic analyzer in an embodiment of the present invention.

具体实施方式Detailed ways

下面结合附图,对本发明的具体实施方式进行详细描述,但应当理解本发明的保护范围并不受具体实施方式的限制。The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

根据本发明实施例,提供了一种基于谐波分析仪的电力谐波分析方法,参见图1所示,本发明实施例中,谐波分析方法的流程如下:According to an embodiment of the present invention, a power harmonic analysis method based on a harmonic analyzer is provided, as shown in FIG. 1 , in the embodiment of the present invention, the flow of the harmonic analysis method is as follows:

步骤101:确定预设基频,根据预设基频为输入信号设计第一FIR梳状滤波器。Step 101: Determine a preset fundamental frequency, and design a first FIR comb filter for an input signal according to the preset fundamental frequency.

该预设基频为输入信号的理论基频,比如电力信号基频的理论值为50Hz,则预设基频设为50Hz。预设基频主要用于设计第一FIR梳状滤波器以及与经过第一FIR梳状滤波器滤波处理后的信号的频率作比较。The preset fundamental frequency is the theoretical fundamental frequency of the input signal. For example, the theoretical fundamental frequency of the power signal is 50 Hz, and the preset fundamental frequency is set to 50 Hz. The preset fundamental frequency is mainly used for designing the first FIR comb filter and comparing with the frequency of the signal filtered by the first FIR comb filter.

步骤102:通过第一FIR梳状滤波器对输入信号进行滤波,并确定滤波后信号的频率。Step 102: Filter the input signal through the first FIR comb filter, and determine the frequency of the filtered signal.

第一FIR梳状滤波器可以滤掉各次谐波,只剩下输入信号的基波,因此滤波后信号主要由基波组成。The first FIR comb filter can filter out all harmonics, leaving only the fundamental wave of the input signal, so the filtered signal is mainly composed of the fundamental wave.

步骤103:当滤波后信号的频率与预设基频之间的差值小于预设阈值时,将滤波后信号的频率作为输入信号的基频。Step 103: When the difference between the frequency of the filtered signal and the preset base frequency is smaller than a preset threshold, use the frequency of the filtered signal as the base frequency of the input signal.

由于实际信号的基频与理论上的预设基频之间存在误差,因此只有当滤波后信号的频率与预设基频之间的差值小于预设阈值时,才将该滤波后信号的频率作为输入信号的基频。其中,预设阈值为预先设定的,具体可以为0.1Hz或0.01Hz等,根据实际情况而定。Since there is an error between the fundamental frequency of the actual signal and the theoretical preset fundamental frequency, only when the difference between the frequency of the filtered signal and the preset fundamental frequency is smaller than the preset threshold, the frequency of the filtered signal is frequency as the fundamental frequency of the input signal. Wherein, the preset threshold is preset, and may be specifically 0.1 Hz or 0.01 Hz, etc., depending on actual conditions.

当滤波后信号的频率与预设基频之间的差值不小于预设阈值时,继续通过第一FIR梳状滤波器对滤波后信号进行滤波,直至再次滤波后信号的频率与预设基频之间的差值小于预设阈值,并将再次滤波后信号的频率作为输入信号的基频。即当滤波后信号的频率与预设基频之间的差值不小于预设阈值时,对已经经过滤波处理后的信号再次进行滤波处理,然后判断再次滤波后信号的频率与预设基频之间的差值是否小于预设阈值,若上述两个频率之间的差值仍然不小于预设阈值,则继续对滤波后的信号进行滤波,直至两个频率之间的差值小于预设阈值。When the difference between the frequency of the filtered signal and the preset base frequency is not less than the preset threshold, continue to filter the filtered signal through the first FIR comb filter until the frequency of the filtered signal is the same as the preset base frequency. The difference between the frequencies is less than the preset threshold, and the frequency of the filtered signal is used as the fundamental frequency of the input signal. That is, when the difference between the frequency of the filtered signal and the preset base frequency is not less than the preset threshold, the filtered signal is filtered again, and then the frequency of the filtered signal and the preset base frequency are judged. Whether the difference between the two frequencies is less than the preset threshold, if the difference between the above two frequencies is still not less than the preset threshold, continue to filter the filtered signal until the difference between the two frequencies is less than the preset threshold threshold.

步骤104:根据基频确定第i次谐波的频率,并为第i次谐波设计第二FIR梳状滤波器。Step 104: Determine the frequency of the i-th harmonic according to the fundamental frequency, and design a second FIR comb filter for the i-th harmonic.

当输入信号的基频确定时,则输入信号中的第i次谐波的频率就可以确定,其为基频的i倍,即第i次谐波的频率fi=if1,其中f1为基频。第二FIR梳状滤波器用于过滤掉输入信号中除第i次谐波之外的其他次谐波,即第二FIR梳状滤波器输出第i次谐波。When the fundamental frequency of the input signal is determined, the frequency of the i-th harmonic in the input signal can be determined, which is i times the fundamental frequency, that is, the frequency of the i-th harmonic is f i =if 1 , where f 1 is the base frequency. The second FIR comb filter is used to filter out other harmonics except the i-th harmonic in the input signal, that is, the second FIR comb filter outputs the i-th harmonic.

步骤105:通过第二FIR梳状滤波器对输入信号进行滤波,确定第i次谐波的信号参数,并将信号参数发送给谐波分析仪的处理单元,该信号参数包括:信号幅值和信号相位角。Step 105: filter the input signal through the second FIR comb filter, determine the signal parameters of the i-th harmonic, and send the signal parameters to the processing unit of the harmonic analyzer, the signal parameters include: signal amplitude and signal phase angle.

在步骤104中可以确定第i次谐波的频率,在步骤105中确定第i次谐波的信号幅值和信号相位角,综合两步骤可以确定第i次谐波的频率,幅值及相位,即确定了第i次谐波的所有信号参数。谐波分析仪接收到第i次谐波的信号参数后,谐波分析仪即可对该谐波进行分析处理,以图表、曲线的方式输出,供相关技术人员进行分析和利用;谐波分析仪还可以通过RS232、RS485标准通讯端口或网口(RJ45)通讯接口,将谐波的信号参数上传至上位机,上位机基于WINDOWS等操作平台,可以将采集的谐波信号参数转换成各种报表、曲线、棒图,同时,报表可根据需要转换为WORD或EXCEL格式。In step 104, the frequency of the i-th harmonic can be determined, and in step 105, the signal amplitude and signal phase angle of the i-th harmonic can be determined. The combination of the two steps can determine the frequency, amplitude and phase of the i-th harmonic , that is, all signal parameters of the i-th harmonic are determined. After the harmonic analyzer receives the signal parameters of the i-th harmonic, the harmonic analyzer can analyze and process the harmonic, and output it in the form of charts and curves for analysis and use by relevant technical personnel; harmonic analysis The instrument can also upload the harmonic signal parameters to the upper computer through the RS232, RS485 standard communication port or the network port (RJ45) communication interface. The upper computer is based on WINDOWS and other operating platforms, and can convert the collected harmonic signal parameters into various Reports, curves, bar graphs, at the same time, reports can be converted to WORD or EXCEL format as required.

本发明实施例中,步骤102和步骤105中的确定信号参数的方法原理具体如下:In the embodiment of the present invention, the principle of the method for determining signal parameters in step 102 and step 105 is specifically as follows:

理想信号x(t)可描述为:x(t)=Xcos(2πft+φ);其中,X是信号幅值,f是信号频率,φ是信号相位角。采用固定时间间隔Δt对连续时间信号x(t)进行离散采样,生成采样序列{x(k)}:The ideal signal x(t) can be described as: x(t)=Xcos(2πft+φ); where X is the signal amplitude, f is the signal frequency, and φ is the signal phase angle. The continuous-time signal x(t) is discretely sampled at a fixed time interval Δt to generate a sampling sequence {x(k)}:

x(k)=Xcos(2πfkΔt+φ)               (2)x(k)=Xcos(2πfkΔt+φ) (2)

因为则式(2)可以表示为:because Then formula (2) can be expressed as:

设a=ej2πfΔtz=Re(a),其中,z为复数a的实部,A*是A的共轭复数,则采样序列{x(k)}为:Let a=e j2πfΔt , z=Re(a), Among them, z is the real part of the complex number a, A * is the conjugate complex number of A, then the sampling sequence {x(k)} is:

x(k)=Aak+A*a-k           (4)x(k)=Aa k +A * a -k (4)

根据欧拉公式eix=cosx+isinx和式(4),设m=2πfΔt,可以得到:According to Euler's formula e ix =cosx+isinx and formula (4), assuming m=2πfΔt, we can get:

x(k)+x(k+2)=A(ak+ak+2)+A*(a-k+a-k-2)x(k)+x(k+2)=A(a k +a k+2 )+A * (a -k +a -k-2 )

=A[cos(mk)+jsin(mk)+cos(mk+2m)+jsin(mk+2m)]+=A[cos(mk)+jsin(mk)+cos(mk+2m)+jsin(mk+2m)]+

A*[cos(mk)-jsin(mk)+cos(mk+2m)-jsin(mk+2m)]A * [cos(mk)-jsin(mk)+cos(mk+2m)-jsin(mk+2m)]

=A[2cos(mk+m)cosm+j2sin(mk+m)cosm]+=A[2cos(mk+m)cosm+j2sin(mk+m)cosm]+

A*[2cos(mk+m)cosm-j2sin(mk+m)cosm]A * [2cos(mk+m)cosm-j2sin(mk+m)cosm]

=2[Aej(mk+m)+A*e-j(mk+m)]cosm=2x(k+1)cosm=2[Ae j(mk+m) +A * e -j(mk+m) ]cosm=2x(k+1)cosm

同时,由于z=Re(a)=Re(cos2πfΔt+jsin2πfΔt)=cos2πfΔt=cosm,结合上式可得:At the same time, since z=Re(a)=Re(cos2πfΔt+jsin2πfΔt)=cos2πfΔt=cosm, combined with the above formula, we can get:

zz == xx (( kk )) ++ xx (( kk ++ 22 )) 22 xx (( kk ++ 11 )) -- -- -- (( 55 ))

又x(k+1)a-x(k)=A[ak+1a-ak]+A*(a-k-1a-a-k)=Aak(a2-1),因此:And x(k+1)ax(k)=A[a k+1 aa k ]+A * (a -k-1 aa -k )=Aa k (a 2 -1), therefore:

AA == xx (( kk ++ 11 )) aa -- xx (( kk )) aa kk (( aa 22 -- 11 )) -- -- -- (( 66 ))

由于z=cos2πfΔt, A = X 2 e jφ = X 2 ( cos φ + j sin φ ) , 因此,对于电力信号x(t),信号频率信号赋值X=2|A|,信号相位角φ=angle(A)。Since z=cos2πfΔt, A = x 2 e jφ = x 2 ( cos φ + j sin φ ) , Therefore, for a power signal x(t), the signal frequency Signal assignment X=2|A|, signal phase angle φ=angle(A).

综上,对于信号x(t),根据三个离散采样值x(k)、x(k+1)、x(k+2)可以确定z,进而可以确定信号x(t)的信号频率f;当信号频率f和采样间隔Δt已知时,可以确定a和A,从而可以确定信号幅值X和信号相位角φ。该算法适用于标准的正弦或余弦信号,因此也适用于电力谐波。以该算法计算信号谐波的参数,容易实现、精度高,而且不受频率漂移的影响,采样频率不必是基波频率的2n倍。In summary, for the signal x(t), z can be determined according to three discrete sampling values x(k), x(k+1), x(k+2), and then the signal frequency f of the signal x(t) can be determined ; When the signal frequency f and the sampling interval Δt are known, a and A can be determined, so that the signal amplitude X and the signal phase angle φ can be determined. The algorithm works for standard sine or cosine signals and therefore also for power harmonics. Using this algorithm to calculate the parameters of signal harmonics is easy to implement, has high precision, and is not affected by frequency drift. The sampling frequency does not have to be 2n times the fundamental frequency.

将以上算法应用于本发明实施例中,在步骤101中,若滤波后信号为x(k),则确定滤波后信号的频率具体包括:Applying the above algorithm to the embodiment of the present invention, in step 101, if the filtered signal is x(k), then determining the frequency of the filtered signal specifically includes:

获取滤波后信号的连续三次采样值x(k)、x(k+1)和x(k+2);Obtain three consecutive sampling values x(k), x(k+1) and x(k+2) of the filtered signal;

滤波后信号的频率为:其中Δt为采样时间间隔。The frequency of the filtered signal is: in Δt is the sampling time interval.

在步骤105中,确定第i次谐波的信号参数具体包括:In step 105, determining the signal parameters of the i-th harmonic specifically includes:

获取第i次谐波的连续两次采样值xi(k)和xi(k+1);Obtain two consecutive sampling values x i (k) and x i (k+1) of the i-th harmonic;

谐波的信号幅值为:Xi=2|Ai|;谐波的信号相位角为:φi=angle(Ai);The harmonic signal amplitude is: X i =2|A i |; the harmonic signal phase angle is: φ i =angle(A i );

其中, A i = x i ( k + 1 ) a i - x i ( k ) a i k ( a i 2 - 1 ) , a i = e j 2 π f i Δt , fi为第i次谐波的频率,Δt为采样时间间隔。in, A i = x i ( k + 1 ) a i - x i ( k ) a i k ( a i 2 - 1 ) , a i = e j 2 π f i Δt , f i is the frequency of the i-th harmonic, and Δt is the sampling time interval.

优选的,第一FIR梳状滤波器和第二FIR梳状滤波器均为FIR窗滤波器;Preferably, both the first FIR comb filter and the second FIR comb filter are FIR window filters;

对于采样序列x(k)=Xcos(2πfkΔt+φ),经过FIR窗滤波器进行滤波处理后:For the sampling sequence x(k)=Xcos(2πfkΔt+φ), after filtering by FIR window filter:

x ~ ( k ) = X 2 e jφ a k Σ n = 0 M - 1 W ( n ) a n + X 2 e - jφ a - k Σ n = 0 M - 1 W ( n ) a n , 其中a=ej2πfΔt Σ n = 0 M - 1 W ( n ) a n 为窗校正因子。 x ~ ( k ) = x 2 e jφ a k Σ no = 0 m - 1 W ( no ) a no + x 2 e - jφ a - k Σ no = 0 m - 1 W ( no ) a no , where a=e j2πfΔt , Σ no = 0 m - 1 W ( no ) a no is the window correction factor.

根据式(5)和式(6)可得,引入窗校正因子WCF的信号的信号参数可以表示为:According to formula (5) and formula (6), the signal of introducing window correction factor WCF The signal parameters of can be expressed as:

ff ~~ == coscos -- 11 (( zz ~~ )) 22 πΔtπΔt ,, Xx ~~ == 22 || AA ~~ || ,, φφ ~~ == amgleamgle (( AA ~~ )) ;;

其中: z ~ = x ~ ( k ) + x ~ ( k + 2 ) 2 x ~ ( k + 1 ) , A ~ = x ~ ( k + 1 ) a - x ~ ( k ) a k ( a 2 - 1 ) × WCF , WCF = Σ n = 0 M - 1 W ( n ) a n . in: z ~ = x ~ ( k ) + x ~ ( k + 2 ) 2 x ~ ( k + 1 ) , A ~ = x ~ ( k + 1 ) a - x ~ ( k ) a k ( a 2 - 1 ) × WCF , WCF = Σ no = 0 m - 1 W ( no ) a no .

普通FIR梳状滤波器在提取出所需频率分量的同时,会改变信号中剩余频率分量的幅度和相位,因此采用FIR窗滤波器代替FIR梳状滤波器。本发明实施例中提供的窗校正因子WCF方法适合于任何有限序列的数字滤波器,例如适用于Hamming、Hanning和Blackman等窗过滤器,甚至有限复杂序列的DFT也包括在内。The ordinary FIR comb filter will change the amplitude and phase of the remaining frequency components in the signal while extracting the required frequency components, so the FIR window filter is used instead of the FIR comb filter. The window correction factor WCF method provided in the embodiment of the present invention is suitable for any finite sequence of digital filters, such as for Hamming, Hanning and Blackman window filters, and even DFT of finite complex sequences is also included.

本发明实施例提供的一种基于谐波分析仪的电力谐波分析方法,该方法很容易实现,可以方便计算出谐波参数,精度高,且该方法不受频率漂移影响,同时采样频率不必是基波频率的2n倍,有效克服了泄露、栅栏效应和混叠效应等严重影响谐波分析精度的缺点。A power harmonic analysis method based on a harmonic analyzer provided by the embodiment of the present invention is easy to implement and can conveniently calculate harmonic parameters with high precision, and the method is not affected by frequency drift, and the sampling frequency does not need to be It is 2n times of the fundamental frequency, which effectively overcomes the shortcomings of leakage, fence effect and aliasing effect that seriously affect the accuracy of harmonic analysis.

下面通过实施例一详细介绍电力谐波分析方法的流程。The flow of the power harmonic analysis method will be described in detail below through Embodiment 1.

实施例一Embodiment one

在实施例一中,采用FIR梳状滤波器对电力信号进行滤波,该FIR梳状滤波器经过加窗处理,其谐波分析过程如图2所示。实施例一中,电力信号波形描述为:采用固定时间间隔Δt对信号x(t)进行采样,生成采样序列:In the first embodiment, an FIR comb filter is used to filter the power signal. The FIR comb filter is processed by windowing, and its harmonic analysis process is shown in FIG. 2 . In Embodiment 1, the power signal waveform is described as: The signal x(t) is sampled at a fixed time interval Δt to generate a sampling sequence:

xx (( kk )) == ΣΣ ii == 11 mm Xx ii coscos (( 22 ππ ff ii kΔtkΔt ++ φφ ii )) kk == 0,1,2,30,1,2,3 .. .. .. .. .. ..

定义 a i = e j 2 π f i Δt , A i = X 2 e j i φ i , zi=Re(ai)=cos2πfiΔt, A i * = X 2 e - j i φ i . definition a i = e j 2 π f i Δt , A i = x 2 e j i φ i , z i = Re(a i ) = cos2πf i Δt, A i * = x 2 e - j i φ i .

根据FIR梳状滤波器的特有性质,可以得出以下结论:According to the unique properties of the FIR comb filter, the following conclusions can be drawn:

ΣΣ nno == 00 22 mm CC (( nno )) xx (( kk ++ nno )) == 00 ;;

C(n)={{1,-2z1,1}*{1,-2z2,1}*...*{1,-2zm,1}},其中,zi=cos2πfiΔt,*为卷积操作符,n为FIR梳状滤波器反馈环的个数。上式为FIR梳状滤波器的特有性质,为现有技术,此处不做详述。C(n)={{1,-2z 1 ,1}*{1,-2z 2 ,1}*...*{1,-2z m ,1}}, where z i =cos2πf i Δt, * is the convolution operator, and n is the number of FIR comb filter feedback loops. The above formula is a unique property of the FIR comb filter, which is a prior art, and will not be described in detail here.

当使用FIR梳状滤波器过滤掉除i次谐波外的其他次谐波信号时,相应的FIR梳状滤波器表达式为:When the FIR comb filter is used to filter out other harmonic signals except the i harmonic, the corresponding FIR comb filter expression is:

CC ii (( nno )) == CC (( nno )) {{ 11 ,, -- 22 zz ii ,, 11 }} == {{ {{ 11 ,, -- 22 zz 11 ,, 11 }} ** .. .. .. ** {{ 11 ,, -- 22 zz ii -- 11 ,, 11 }} ** {{ 11 ,, -- 22 zz ii ++ 11 ,, 11 }} ** .. .. .. ** {{ 11 ,, -- 22 zz mm ,, 11 }} }} ..

实施例一中,谐波分析的流程具体如下:In Embodiment 1, the process of harmonic analysis is specifically as follows:

预设基频f=60Hz,设计滤波器C1(n)。The preset fundamental frequency is f=60Hz, and the filter C 1 (n) is designed.

其中,C1(n)={{1,-2z2,1}*{1,-2z3,1}*...*{1,-2zm,1}}。Wherein, C 1 (n)={{1,-2z 2 ,1}*{1,-2z 3 ,1}*...*{1,-2z m ,1}}.

离散电力信号x(k)经过滤波器C1(n)滤波后,所得信号波形表达式为:After the discrete power signal x(k) is filtered by the filter C1(n), the obtained signal waveform expression is:

xx ~~ 11 (( kk )) == ΣΣ nno == 00 22 mm -- 22 CC 11 (( nno )) xx (( kk ++ nno )) ..

获取的连续三个采样值根据式(5)可以确定,经过滤波器C1(n)滤波后的信号的频率为:Obtain Three consecutive samples of and According to formula (5), it can be determined that the frequency of the signal filtered by the filter C 1 (n) is:

f new = cos - 1 ( z 1 ) 2 πΔt , 其中, z 1 = x ~ 1 ( k ) + x ~ 1 ( k + 2 ) 2 x ~ 1 ( k + 1 ) . f new = cos - 1 ( z 1 ) 2 πΔt , in, z 1 = x ~ 1 ( k ) + x ~ 1 ( k + 2 ) 2 x ~ 1 ( k + 1 ) .

判断|fnew-f|<0.001Hz是否成立。其中0.001Hz即为预设阈值,|fnew-f|<0.001Hz即为判断滤波后信号的频率fnew与预设基频60Hz之间的差值是否小于预设阈值0.001Hz。Judging whether |f new -f|<0.001Hz is true. Where 0.001Hz is the preset threshold, and |f new -f|<0.001Hz is to judge whether the difference between the frequency f new of the filtered signal and the preset base frequency 60Hz is less than the preset threshold 0.001Hz.

当|fnew-f|<0.001Hz成立时,将fnew作为电力信号x(k)的基频f1;当不成立时,则继续通过滤波器C1(n)对进行滤波,直至滤波后信号的频率与预设基频60Hz之间的差值小于预设阈值。When |f new -f|<0.001Hz is established, take f new as the fundamental frequency f 1 of the power signal x(k); when it is not established, continue to pass through the filter C 1 (n) to Filtering is performed until the difference between the frequency of the filtered signal and the preset fundamental frequency of 60 Hz is smaller than the preset threshold.

当基频f1确定后,根据式(6),可以确定基波的幅值和相位角:When the fundamental frequency f1 is determined, according to formula (6), the amplitude and phase angle of the fundamental wave can be determined:

X1=2|A1|,φ1=angle(A1);其中:X 1 =2|A 1 |, φ 1 =angle(A 1 ); where:

AA 11 == xx ~~ 11 (( kk ++ 11 )) aa 11 -- xx ~~ 11 (( kk )) aa 11 kk (( aa 11 22 -- 11 )) &times;&times; WCFWCF 11 ,, WCFWCF 11 == &Sigma;&Sigma; nno == 00 22 mm -- 22 CC 11 (( nno )) aa 11 nno ..

根据基频f1可以确定第i次谐波的频率,然后根据所需的第i次谐波设计滤波器Ci(n),Ci(n)={{1,-2z1,1}*...*{1,-2zi-1,1}*{1,-2zi+1,1}*...*{1,-2zm,1}}。According to the fundamental frequency f 1 , the frequency of the i-th harmonic can be determined, and then the filter C i (n) can be designed according to the required i-th harmonic, C i (n)={{1,-2z 1 ,1} *...*{1,-2z i-1 ,1}*{1,-2z i+1 ,1}*...*{1,-2z m ,1}}.

离散电力信号x(k)经过滤波器Ci(n)滤波后,所得第i次谐波的表达式为:After the discrete power signal x(k) is filtered by the filter C i (n), the expression of the i-th harmonic obtained is:

xx ~~ 11 (( kk )) == &Sigma;&Sigma; nno == 00 22 mm -- 22 CC ii (( nno )) xx (( kk ++ nno ))

第i次谐波的的幅值和相位角分别为:The amplitude and phase angle of the i-th harmonic are:

Xi=2|Ai|,φi=angle(Ai);其中:X i =2|A i |, φ i =angle(A i ); where:

AA ii == xx ~~ ii (( kk ++ 11 )) aa ii -- xx ~~ ii (( kk )) aa ii kk (( aa ii 22 -- 11 )) &times;&times; WCFWCF ii ,, WCFWCF ii == &Sigma;&Sigma; nno == 00 22 mm -- 22 CC ii (( nno )) aa ii nno ,, aa ii == ee jj 22 &pi;&pi; ff ii &Delta;t&Delta;t == aa 11 ii ..

因此,获取第i次谐波的连续两次采样值即可确定第i次谐波的幅值和相位角。Therefore, to obtain the i-th harmonic Two consecutive sampling values of and The amplitude and phase angle of the i-th harmonic can be determined.

本发明实施例提供的一种基于谐波分析仪的电力谐波分析方法,该方法很容易实现,可以方便计算出谐波参数,精度高,且该方法不受频率漂移影响,同时采样频率不必是基波频率的2n倍,有效克服了泄露、栅栏效应和混叠效应等严重影响谐波分析精度的缺点。采用窗校正因子方法,可以适用于任何有限序列的数字滤波器,并且可以选择不同的窗口算法和窗口大小获取更好的性能。本发明实施例提供的一种基于谐波分析仪的电力谐波分析方法适合于有需求的脱机应用,且如果可以用并行计算实现该谐波分析方法,则也适合于在线应用。A power harmonic analysis method based on a harmonic analyzer provided by an embodiment of the present invention is easy to implement and can conveniently calculate harmonic parameters with high precision, and the method is not affected by frequency drift, and the sampling frequency does not need to be It is 2n times of the fundamental frequency, which effectively overcomes the shortcomings of leakage, fence effect and aliasing effect that seriously affect the accuracy of harmonic analysis. Using the window correction factor method, it can be applied to any finite sequence of digital filters, and different window algorithms and window sizes can be selected to obtain better performance. A power harmonic analysis method based on a harmonic analyzer provided by an embodiment of the present invention is suitable for off-line applications in need, and if the harmonic analysis method can be realized by parallel computing, it is also suitable for online applications.

以上详细介绍了一种基于谐波分析仪的电力谐波分析方法的实现过程,本发明实施例还提供一种谐波分析仪,下面介绍谐波分析仪的结构。The implementation process of a power harmonic analysis method based on a harmonic analyzer is introduced in detail above. Embodiments of the present invention also provide a harmonic analyzer. The structure of the harmonic analyzer is introduced below.

本发明实施例提供的一种谐波分析仪,参见图3所示,包括:第一滤波设计模块301、第一滤波模块302、基频确定模块303、第二滤波设计模块304和第二滤波模块305。A harmonic analyzer provided by an embodiment of the present invention, as shown in FIG. 3 , includes: a first filter design module 301, a first filter module 302, a fundamental frequency determination module 303, a second filter design module 304 and a second filter Module 305.

第一滤波设计模块301用于确定预设基频,根据预设基频为输入信号设计第一FIR梳状滤波器;The first filtering design module 301 is used to determine the preset fundamental frequency, and design a first FIR comb filter for the input signal according to the preset fundamental frequency;

第一滤波模块302用于通过第一FIR梳状滤波器对输入信号进行滤波,并确定滤波后信号的频率;The first filtering module 302 is configured to filter the input signal through a first FIR comb filter, and determine the frequency of the filtered signal;

基频确定模块303用于当滤波后信号的频率与预设基频之间的差值小于预设阈值时,将滤波后信号的频率作为输入信号的基频;The base frequency determination module 303 is used to use the frequency of the filtered signal as the base frequency of the input signal when the difference between the frequency of the filtered signal and the preset base frequency is less than a preset threshold;

第二滤波设计模块304用于根据基频确定谐波的频率,并为谐波设计第二FIR梳状滤波器;The second filtering design module 304 is used to determine the frequency of the harmonic according to the fundamental frequency, and designs a second FIR comb filter for the harmonic;

第二滤波模块305用于通过第二FIR梳状滤波器对输入信号进行滤波,确定谐波的信号参数,并将信号参数发送给谐波分析仪的处理单元,信号参数包括:信号幅值和信号相位角。The second filter module 305 is used to filter the input signal through the second FIR comb filter, determine the signal parameters of the harmonics, and send the signal parameters to the processing unit of the harmonic analyzer, the signal parameters include: signal amplitude and signal phase angle.

优选的,第一滤波模块302还用于:当滤波后信号的频率与预设基频之间的差值不小于预设阈值时,继续通过第一FIR梳状滤波器对滤波后信号进行滤波,直至再次滤波后信号的频率与预设基频之间的差值小于预设阈值;Preferably, the first filtering module 302 is also used for: when the difference between the frequency of the filtered signal and the preset fundamental frequency is not less than the preset threshold, continue to filter the filtered signal through the first FIR comb filter , until the difference between the frequency of the filtered signal and the preset fundamental frequency is smaller than the preset threshold;

基频确定模块303还用于:将再次滤波后信号的频率作为输入信号的基频。The fundamental frequency determination module 303 is further configured to: use the frequency of the filtered signal again as the fundamental frequency of the input signal.

优选的,第一滤波模块302包括:Preferably, the first filtering module 302 includes:

第一采集单元,用于获取滤波后信号的连续三次采样值x(k)、x(k+1)和x(k+2);The first acquisition unit is used to obtain three consecutive sampling values x(k), x(k+1) and x(k+2) of the filtered signal;

第一计算单元,用于确定滤波后信号的频率为:其中Δt为采样时间间隔。The first calculation unit is used to determine the frequency of the filtered signal as: in Δt is the sampling time interval.

优选的,第二滤波模块305包括:Preferably, the second filtering module 305 includes:

第二采集单元,用于获取谐波的连续两次采样值xi(k)和xi(k+1);The second acquisition unit is used to obtain two consecutive sampling values x i (k) and x i (k+1) of the harmonic;

第二计算单元,用于确定谐波的信号幅值为:Xi=2|Ai|;确定谐波的信号相位角为:φi=angle(Ai);The second calculation unit is used to determine the signal amplitude of the harmonic: X i =2|A i |; determine the phase angle of the signal of the harmonic: φ i =angle(A i );

其中, fi为谐波的频率,Δt为采样时间间隔。in, f i is the frequency of the harmonic, and Δt is the sampling time interval.

优选的,第一滤波设计模块301确定的第一FIR梳状滤波器和第二滤波设计模块304确定的第二FIR梳状滤波器为FIR窗滤波器;Preferably, the first FIR comb filter determined by the first filter design module 301 and the second FIR comb filter determined by the second filter design module 304 are FIR window filters;

对于采样序列x(k)=Xcos(2πfkΔt+φ),经过FIR窗滤波器进行滤波处理后:For the sampling sequence x(k)=Xcos(2πfkΔt+φ), after filtering by FIR window filter:

x ~ ( k ) = X 2 e j&phi; a k &Sigma; n = 0 M - 1 W ( n ) a n + X 2 e - j&phi; a - k &Sigma; n = 0 M - 1 W ( n ) a n , 其中a=ej2πfΔt, &Sigma; n = 0 M - 1 W ( n ) a n 为窗校正因子。 x ~ ( k ) = x 2 e j&phi; a k &Sigma; no = 0 m - 1 W ( no ) a no + x 2 e - j&phi; a - k &Sigma; no = 0 m - 1 W ( no ) a no , where a=e j2πfΔt , &Sigma; no = 0 m - 1 W ( no ) a no is the window correction factor.

优选的,当第二FIR梳状滤波器为FIR窗滤波器时,第二滤波模块305包括:Preferably, when the second FIR comb filter is an FIR window filter, the second filtering module 305 includes:

第三采集单元,用于获取谐波的连续两次采样值 The third acquisition unit is used to obtain two consecutive sampling values of harmonics and

第三计算单元,用于确定谐波的信号幅值为:Xi=2|Ai|;确定谐波的信号相位角为:φi=angle(Ai);The third calculation unit is used to determine the signal amplitude of the harmonic: X i =2|A i |; determine the phase angle of the harmonic signal: φ i =angle(A i );

其中, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) &times; WCF i , a i = e j 2 &pi; f i &Delta;t , WCF i = &Sigma; n = 0 M - 1 W ( n ) a i n , fi为谐波的频率,Δt为采样时间间隔。in, A i = x ~ i ( k + 1 ) a i - x ~ i ( k ) a i k ( a i 2 - 1 ) &times; WCF i , a i = e j 2 &pi; f i &Delta;t , WCF i = &Sigma; no = 0 m - 1 W ( no ) a i no , f i is the frequency of the harmonic, and Δt is the sampling time interval.

本发明实施例提供的一种谐波分析仪,能够根据谐波采样值快速计算出谐波参数,精度高,且不受频率漂移影响,同时采样频率不必是基波频率的2n倍,有效克服了泄露、栅栏效应和混叠效应等严重影响谐波分析精度的缺点。A harmonic analyzer provided by an embodiment of the present invention can quickly calculate harmonic parameters according to harmonic sampling values, has high precision, and is not affected by frequency drift. At the same time, the sampling frequency does not have to be 2 n times the fundamental frequency, effectively It overcomes the shortcomings that seriously affect the accuracy of harmonic analysis such as leakage, fence effect and aliasing effect.

本发明能有多种不同形式的具体实施方式,上面以图1-图3为例结合附图对本发明的技术方案作举例说明,这并不意味着本发明所应用的具体实例只能局限在特定的流程或实施例结构中,本领域的普通技术人员应当了解,上文所提供的具体实施方案只是多种优选用法中的一些示例,任何体现本发明权利要求的实施方式均应在本发明技术方案所要求保护的范围之内。The present invention can have multiple specific implementations in different forms. Above, the technical solutions of the present invention are illustrated by taking Fig. 1-Fig. 3 as an example in conjunction with the accompanying drawings. In the specific process or embodiment structure, those of ordinary skill in the art should understand that the specific implementations provided above are only some examples of various preferred usages, and any implementation that embodies the claims of the present invention shall be included in the present invention. Within the scope of protection required by the technical solution.

最后应说明的是:以上仅为本发明的优选实施例而已,并不用于限制本发明,尽管参照前述实施例对本发明进行了详细的说明,对于本领域的技术人员来说,其依然可以对前述各实施例所记载的技术方案进行修改,或者对其中部分技术特征进行等同替换。凡在本发明的精神和原则之内,所作的任何修改、等同替换、改进等,均应包含在本发明的保护范围之内。Finally, it should be noted that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand The technical solutions recorded in the foregoing embodiments are modified, or some of the technical features are equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (12)

1. A power harmonic analysis method based on a harmonic analyzer is characterized by comprising the following steps:
determining a preset fundamental frequency, and designing a first FIR comb filter for an input signal according to the preset fundamental frequency;
filtering the input signal through the first FIR comb filter and determining the frequency of the filtered signal;
when the difference value between the frequency of the filtered signal and the preset fundamental frequency is smaller than a preset threshold value, taking the frequency of the filtered signal as the fundamental frequency of the input signal;
determining the frequency of a harmonic according to the fundamental frequency, and designing a second FIR comb filter for the harmonic;
filtering the input signal through the second FIR comb filter, determining signal parameters of the harmonic waves, and sending the signal parameters to a processing unit of a harmonic wave analyzer, wherein the signal parameters include: signal amplitude and signal phase angle.
2. The method of claim 1, further comprising:
and when the difference value between the frequency of the filtered signal and the preset fundamental frequency is not less than a preset threshold value, continuing to filter the filtered signal through the first FIR comb filter until the difference value between the frequency of the re-filtered signal and the preset fundamental frequency is less than the preset threshold value, and taking the frequency of the re-filtered signal as the fundamental frequency of the input signal.
3. The method of claim 1 or 2, wherein determining the frequency of the filtered signal comprises:
acquiring three sampling values x (k), x (k +1) and x (k +2) of the filtered signal;
determining the frequency of the filtered signal as:whereinΔ t is the sampling time interval.
4. The method of claim 1 or 2, wherein said determining signal parameters of said harmonics comprises:
obtaining two consecutive sample values x of the harmonici(k) And xi(k+1);
Determining the signal amplitude of the harmonic as: xi=2|Ai|;
Determining a signal phase angle of the harmonic as: phi is ai=angle(Ai);
Wherein, fiat is the frequency of the harmonic, Δ t is the sampling time interval.
5. The method of claim 1 or 2, wherein the first FIR comb filter and the second FIR comb filter are FIR window filters;
for the sampling sequence x (k) = Xcos (2 pi fk Δ t + phi), after filtering processing is performed by an FIR window filter:
<math> <mrow> <mover> <mi>x</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mi>X</mi> <mn>2</mn> </mfrac> <msup> <mi>e</mi> <mi>j&phi;</mi> </msup> <msup> <mi>a</mi> <mi>k</mi> </msup> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> <mo>+</mo> <mfrac> <mi>X</mi> <mn>2</mn> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>j&phi;</mi> </mrow> </msup> <msup> <mi>a</mi> <mrow> <mo>-</mo> <mi>k</mi> </mrow> </msup> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> <mo>,</mo> </mrow> </math> wherein a = ej2πfΔt, <math> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> </mrow> </math> Is a window correction factor.
6. The method of claim 5, wherein said determining signal parameters of said harmonics comprises:
obtaining two consecutive sample values of the harmonicAnd
determining the signal amplitude of the harmonic as: xi=2|Ai|;
Determining a signal phase angle of the harmonic as: phi is ai=angle(Ai);
Wherein, <math> <mrow> <msub> <mi>A</mi> <mi>i</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mover> <mi>x</mi> <mo>~</mo> </mover> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>-</mo> <msub> <mover> <mi>x</mi> <mo>~</mo> </mover> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mi>k</mi> </msup> <mrow> <mo>(</mo> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mn>2</mn> </msup> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>&times;</mo> <msub> <mi>WCF</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> </mrow> </math> <math> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mi>j</mi> <mn>2</mn> <mi>&pi;</mi> <msub> <mi>f</mi> <mi>i</mi> </msub> <mi>&Delta;t</mi> </mrow> </msup> <mo>,</mo> </mrow> </math> <math> <mrow> <msub> <mi>WCF</mi> <mi>i</mi> </msub> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mi>n</mi> </msup> <mo>,</mo> </mrow> </math> fiat is the frequency of the harmonic, Δ t is the sampling time interval.
7. A harmonic analyzer, comprising:
the first filtering design module is used for determining a preset fundamental frequency and designing a first FIR comb filter for an input signal according to the preset fundamental frequency;
a first filtering module, configured to filter the input signal through the first FIR comb filter, and determine a frequency of the filtered signal;
a fundamental frequency determining module, configured to, when a difference between the frequency of the filtered signal and the preset fundamental frequency is smaller than a preset threshold, take the frequency of the filtered signal as the fundamental frequency of the input signal;
the second filtering design module is used for determining the frequency of the harmonic wave according to the fundamental frequency and designing a second FIR comb filter for the harmonic wave;
a second filtering module, configured to filter the input signal through the second FIR comb filter, determine a signal parameter of the harmonic, and send the signal parameter to a processing unit of a harmonic analyzer, where the signal parameter includes: signal amplitude and signal phase angle.
8. The harmonic analyzer of claim 7, wherein the first filtering module is further configured to: when the difference value between the frequency of the filtered signal and the preset fundamental frequency is not less than a preset threshold value, continuing to filter the filtered signal through the first FIR comb filter until the difference value between the frequency of the re-filtered signal and the preset fundamental frequency is less than the preset threshold value;
the fundamental frequency determination module is further configured to: and taking the frequency of the re-filtered signal as the fundamental frequency of the input signal.
9. The harmonic analyzer of claim 7 or 8, wherein the first filtering module comprises:
the first acquisition unit is used for acquiring sampling values x (k), x (k +1) and x (k +2) of the filtered signal in three consecutive times;
a first calculating unit, configured to determine that a frequency of the filtered signal is:whereinΔ t is the sampling time interval.
10. The harmonic analyzer of claim 7 or 8, wherein the second filtering module comprises:
a second acquisition unit for acquiring two consecutive sampling values x of the harmonici(k) And xi(k+1);
A second calculation unit for determining the signal amplitude of the harmonic as: xi=2|AiL, |; determining a signal phase angle of the harmonic as: phi is ai=angle(Ai);
Wherein, fiat is the frequency of the harmonic, Δ t is the sampling time interval.
11. The harmonic analyzer of claim 7 or 8, wherein the first FIR comb filter determined by the first filter design module and the second FIR comb filter determined by the second filter design module are FIR window filters;
for the sampling sequence x (k) = Xcos (2 pi fk Δ t + phi), after filtering processing is performed by an FIR window filter:
<math> <mrow> <mover> <mi>x</mi> <mo>~</mo> </mover> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mi>X</mi> <mn>2</mn> </mfrac> <msup> <mi>e</mi> <mi>j&phi;</mi> </msup> <msup> <mi>a</mi> <mi>k</mi> </msup> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> <mo>+</mo> <mfrac> <mi>X</mi> <mn>2</mn> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>j&phi;</mi> </mrow> </msup> <msup> <mi>a</mi> <mrow> <mo>-</mo> <mi>k</mi> </mrow> </msup> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> <mo>,</mo> </mrow> </math> wherein a = ej2πfΔt, <math> <mrow> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <mi>a</mi> <mi>n</mi> </msup> </mrow> </math> Is a window correction factor.
12. The harmonic analyzer of claim 11, wherein the second filtering module comprises:
a third acquisition unit for acquiring two consecutive sampling values of the harmonicAnd x
A third calculation unit for determining the signal amplitude of the harmonic as: xi=2|AiL, |; determining a signal phase angle of the harmonic as: phi is ai=angle(Ai);
Wherein, <math> <mrow> <msub> <mi>A</mi> <mi>i</mi> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mover> <mi>x</mi> <mo>~</mo> </mover> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>-</mo> <msub> <mover> <mi>x</mi> <mo>~</mo> </mover> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mi>k</mi> </msup> <mrow> <mo>(</mo> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mn>2</mn> </msup> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>&times;</mo> <msub> <mi>WCF</mi> <mi>i</mi> </msub> </mrow> </mfrac> <mo>,</mo> </mrow> </math> <math> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mi>j</mi> <mn>2</mn> <mi>&pi;</mi> <msub> <mi>f</mi> <mi>i</mi> </msub> <mi>&Delta;t</mi> </mrow> </msup> <mo>,</mo> </mrow> </math> <math> <mrow> <msub> <mi>WCF</mi> <mi>i</mi> </msub> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>M</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <mi>W</mi> <mrow> <mo>(</mo> <mi>n</mi> <mo>)</mo> </mrow> <msup> <msub> <mi>a</mi> <mi>i</mi> </msub> <mi>n</mi> </msup> <mo>,</mo> </mrow> </math> fiat is the frequency of the harmonic, Δ t is the sampling time interval.
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