Wideband oscillation component detection method and system based on cascaded high-order complex filter
By combining a cascaded high-order complex filter and a frequency-locked loop (FLL), the influence of unknown frequencies in the detection of broadband oscillation components is resolved, enabling accurate detection of the fundamental and resonant components and ensuring the effective operation of the broadband oscillation damping device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
- Filing Date
- 2026-06-26
- Publication Date
- 2026-07-24
AI Technical Summary
Existing broadband oscillation component detection methods struggle to accurately detect the fundamental component when the frequency is unknown, and cannot effectively separate multiple resonant frequencies, thus affecting the effectiveness of broadband oscillation damping devices.
By employing cascaded high-order complex filters and configuring a frequency-locked loop (FLL), the fundamental frequency and resonant components are detected through successive filtering. The positive and negative sequence components are extracted using a first-order decoupled complex filter, thereby achieving frequency adaptation.
Accurate detection of the fundamental component and separation of multiple resonant components and their frequencies eliminate the influence of unknown frequencies, providing reliable detection assurance for broadband oscillation damping devices.
Smart Images
Figure CN122449201A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of novel power system broadband oscillation component detection technology, specifically relating to a broadband oscillation component detection method and system based on cascaded high-order complex filters. Background Technology
[0002] With the rapid increase in the proportion of power electronic equipment such as wind power, photovoltaics, and energy storage in the power grid, the broadband oscillation problem induced by these technologies has become increasingly serious, posing a significant threat to the safe and stable operation of the system. Configuring broadband oscillation damping devices is one of the important means to suppress broadband oscillations. The broadband oscillation component detection method is a key component of the damping device's control algorithm, directly determining the effectiveness of the device's execution; therefore, this detection method is of great significance.
[0003] Currently, broadband oscillation component detection methods mainly include direct detection methods and indirect detection methods. Direct detection methods directly detect the resonant component through resonance detection, including methods such as Fourier transform, wavelet transform, and mode decomposition. Indirect detection methods first detect the fundamental component of the signal, then subtract it from the original signal to obtain the resonant component. Fundamental component detection methods mainly include synchronous phase-locked loops, second-order generalized integrators, and adaptive notch filters. Direct resonant component detection typically requires data support from a phasor measurement unit (PMU) to obtain high-precision, time-stamped synchronous phasor data. Simultaneously, by performing spectral analysis, modal parameter extraction, or time-frequency transformation on the PMU data, key characteristics such as oscillation frequency, damping ratio, and amplitude can be identified. However, direct detection methods are mainly suitable for offline analysis, post-accident identification, and oscillation feature extraction in wide-area monitoring systems. They are difficult to apply directly to the control of broadband oscillation damping devices requiring real-time response, mainly due to limitations in algorithm computational complexity and data window delay. Therefore, wideband oscillation damping devices typically employ indirect detection methods.
[0004] As is known from the principle of indirect resonant component detection methods, accurate detection of the fundamental frequency component is crucial. To improve the accuracy of fundamental frequency component detection, existing research involves connecting multiple second-order generalized integrators or adaptive notch filters in parallel to prevent the adverse effects of background harmonics on the detection accuracy. However, parallel schemes require prior knowledge of the frequency to be detected, and the influence of unknown frequency components remains unsuppressed. Furthermore, conventional parallel resonant methods can only obtain the sum of resonant components, failing to detect the specific resonant frequency and also unable to separate multiple unknown frequency resonant components. Summary of the Invention
[0005] The purpose of this invention is to provide a broadband oscillation component detection method based on cascaded high-order complex filters, which can solve the problem of eliminating the influence of unknown frequencies on the detection of fundamental components.
[0006] To achieve the above objectives, this invention provides a broadband oscillation component detection method based on cascaded high-order complex filters. The method includes: cascading multiple high-order decoupled complex filters to form a cascaded high-order decoupled complex filter, and configuring a frequency-locked loop (FLL) in each high-order decoupled complex filter; the input of the cascaded high-order decoupled complex filter is... The frequency domain voltage component in the coordinate system is detected by the cascaded high-order decoupled complex filter to obtain a wideband oscillation component. This wideband oscillation component is the fundamental component and multiple resonant components obtained after successive filtering by multiple high-order decoupled complex filters. The input of each intermediate stage of the cascaded high-order decoupled complex filter is the fundamental or resonant component output by the previous stage of the high-order decoupled complex filter and the voltage error signal. Each high-order decoupled complex filter is composed of multiple cascaded first-order decoupled complex filters, and each first-order decoupled complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter.
[0007] Preferably, the cascaded high-order decoupling complex filter includes A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, wherein: the input of the first high-order decoupling complex filter is the input to the cascaded high-order decoupling complex filter. In the frequency domain voltage component of the coordinate system, the output of the first higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first higher-order decoupling complex filter includes the fundamental positive-sequence component and the fundamental negative-sequence component. The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive-sequence component and the first resonant negative-sequence component. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
[0008] Preferably, each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter is used in each higher-order decoupling complex filter to extract positive-sequence and negative-sequence components. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter. The input of each intermediate first-order decoupling complex filter in the higher-order decoupling complex filter is the positive-sequence and negative-sequence components output by the previous first-order decoupling complex filter.
[0009] Preferably, the higher-order decoupling complex filter includes a higher-order positive-order decoupling complex filter and a higher-order negative-order decoupling complex filter, wherein the transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of the first-order positive-order complex filter is obtained, and the transfer function of the higher-order negative-order decoupling complex filter is based on the corresponding... The transfer functions of the first-order negative-order complex filters are obtained; wherein, the transfer functions of the first-order positive-order complex filters and the first-order negative-order complex filters are obtained based on the cutoff frequency of the first-order decoupled complex filters and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output.
[0010] Preferably, the broadband oscillation component detection method based on cascaded high-order complex filters provided by the present invention includes: Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).
[0011] Preferably, in In each frequency-locked loop (FLL): the first FLL corresponds to the first higher-order decoupling complex filter, including: based on the fundamental positive-sequence component output by the first higher-order decoupling complex filter... In the shaft component and the first voltage error signal The fundamental angular frequency is obtained from the axial component; the second frequency-locked loop (FLL) corresponds to the second higher-order decoupling complex filter, including: based on the first resonant positive sequence component output by the second higher-order decoupling complex filter... Shaft component and second voltage error signal The first resonant angular frequency is obtained from the axial component; the second... Frequency Locked Loop (FLL) and the first Higher-order decoupling complex filters correspond to, including: according to the first The first output of a high-order decoupling complex filter In the resonant positive sequence component Axis components and the first Voltage error signal The axis component is obtained as follows The resonant angular frequency; wherein, the fundamental angular frequency is input to each first-order decoupling complex filter in the first higher-order decoupling complex filter, and the first resonant angular frequency is input to each first-order decoupling complex filter in the second higher-order decoupling complex filter, wherein the first... The resonant angular frequency is input to the first Each first-order decoupling complex filter in the higher-order decoupling complex filter; wherein, in the first voltage error signal The axis components are input to the first higher-order decoupling complex filter. In the axial frequency domain voltage component and the fundamental positive sequence component In the axial components and fundamental negative sequence components The shaft component is calculated; in the second voltage error signal The shaft component is based on the first voltage error signal. Axial components, first resonant positive sequence components In the axial component and the first resonant negative sequence component The axis components are calculated; the first Voltage error signal Axis components according to the first Voltage error signal Axis component, first The α-axis component and the first harmonic positive sequence component The α-axis component of the resonant negative sequence component is calculated.
[0012] Accordingly, the present invention also provides a wideband oscillation component detection system based on cascaded high-order complex filters. This system includes: a cascaded high-order decoupled complex filter comprising multiple high-order decoupled complex filters and multiple frequency-locked loops (FLLs). The cascaded high-order decoupled complex filter is composed of multiple cascaded high-order decoupled complex filters, and each high-order decoupled complex filter is configured with a frequency-locked loop (FLL). Each high-order decoupled complex filter is composed of multiple cascaded first-order decoupled complex filters, and each first-order decoupled complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter. The input of the cascaded high-order decoupled complex filter is... The frequency domain voltage component in the coordinate system is detected by the cascaded high-order decoupling complex filter to obtain a wideband oscillation component. This wideband oscillation component is the fundamental component and multiple resonant components obtained after successive filtering by multiple high-order decoupling complex filters. The input of the intermediate stages of the cascaded high-order decoupling complex filter is the fundamental or resonant component output by the previous stage of the high-order decoupling complex filter and the voltage error signal.
[0013] Preferably, the cascaded high-order decoupling complex filter includes A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, wherein: the input of the first high-order decoupling complex filter is the input to the cascaded high-order decoupling complex filter. In the frequency domain voltage component of the coordinate system, the output of the first higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first higher-order decoupling complex filter includes the fundamental positive-sequence component and the fundamental negative-sequence component. The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive-sequence component and the first resonant negative-sequence component. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
[0014] Preferably, each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter is used in each higher-order decoupling complex filter to extract positive-sequence and negative-sequence components. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter. The input of each intermediate first-order decoupling complex filter in the higher-order decoupling complex filter is the positive-sequence and negative-sequence components output by the previous first-order decoupling complex filter.
[0015] Preferably, the higher-order decoupling complex filter includes a higher-order positive-order decoupling complex filter and a higher-order negative-order decoupling complex filter, wherein the transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of the first-order positive-order complex filter is obtained, and the transfer function of the higher-order negative-order decoupling complex filter is based on the corresponding... The transfer functions of the first-order negative-order complex filters are obtained, wherein the transfer functions of the first-order positive-order complex filters and the first-order negative-order complex filters are based on the cutoff frequency of the first-order decoupled complex filters and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output; wherein, the broadband oscillation component detection system further includes Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).
[0016] The beneficial effects of this invention are as follows:
[0017] Compared with conventional parallel decoupling multi-complex filters, the technical solution provided by this invention can eliminate the influence of unknown frequencies on the detection of fundamental components, accurately detect fundamental components, and realize the detection of multiple resonant components and their resonant frequencies, thus ensuring the smooth implementation of the broadband oscillation damping device suppression algorithm. Attached Figure Description
[0018] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:
[0019] Figure 1 This invention provides a method for detecting wideband oscillation components based on cascaded high-order complex filters.
[0020] Figure 2 This invention provides a high-order decoupling complex filter;
[0021] Figure 3 This invention provides a method for implementing a high-order decoupling complex filter.
[0022] Figure 4 This is the three-phase voltage provided by the present invention;
[0023] Figure 5 This invention provides The fundamental component and its frequency in the coordinate system, where, Figure 5 (a) in the middle is The fundamental component in the coordinate system, Figure 5 In this context, (b) represents the fundamental frequency;
[0024] Figure 6 This invention provides The first example resonant component and its frequency in the coordinate system, where... Figure 6 (a) in the middle is The first example resonant component in the coordinate system. Figure 6 In the example, (b) is the frequency of the first example resonant component;
[0025] Figure 7 This invention provides The second example resonant component and its frequency in the coordinate system, wherein, Figure 7 (a) in the middle is The second example resonant component in the coordinate system. Figure 7 In the example, (b) is the frequency of the second example resonant component. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.
[0027] Figure 1 This invention provides a broadband oscillation component detection method based on cascaded high-order complex filters, such as... Figure 1 As shown, the method includes: cascading multiple high-order decoupling complex filters to form a cascaded high-order decoupling complex filter, and configuring a frequency-locked loop (FLL) in each high-order decoupling complex filter; the input of the cascaded high-order decoupling complex filter is... The frequency domain voltage component in the coordinate system is detected by a cascaded high-order decoupled complex filter to obtain a broadband oscillation component. This broadband oscillation component is the fundamental component and multiple resonant components obtained after successive filtering by multiple high-order decoupled complex filters. The input of each intermediate stage of the cascaded high-order decoupled complex filter is the fundamental or resonant component output by the previous stage of the high-order decoupled complex filter and the voltage error signal. Each high-order decoupled complex filter is composed of multiple cascaded first-order decoupled complex filters, and each first-order decoupled complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter.
[0028] according to Figure 1 As can be seen, the wideband oscillation component detection algorithm based on cascaded high-order decoupled complex filters provided by this invention consists of n cascaded high-order decoupled complex filters, the number of which is... The appropriate filter can be selected based on actual needs. To avoid the adverse effects of power grid frequency fluctuations on the detection accuracy of the fundamental and broadband oscillation components, each high-order decoupled complex filter achieves frequency adaptation through a frequency-locked loop (FLL).
[0029] First, the three-phase voltage , , Obtained through Clarke transform The time-domain voltage component in the coordinate system is shown in equation (1):
[0030] (1)
[0031] in, , and These are the grid voltages for phases A, B, and C, respectively. and They are respectively coordinate system shaft and The time-domain voltage component of the axis will The time-domain voltage component in the coordinate system is transformed by Laplace to... Frequency domain voltage components in the coordinate system.
[0032] Cascaded high-order decoupling complex filters include A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, where:
[0033] The input of the first high-order decoupled complex filter is the frequency domain voltage component in the αβ coordinate system input to the cascaded high-order decoupled complex filter. The output of the first high-order decoupled complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first high-order decoupled complex filter includes the fundamental positive sequence component and the fundamental negative sequence component.
[0034] The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive sequence component and the first resonant negative sequence component.
[0035] No. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
[0036] Will Frequency domain voltage components in coordinate system Axial components and Axial components The input is fed to a first higher-order decoupling complex filter. The output of the first higher-order decoupling complex filter includes the fundamental positive-sequence component. Fundamental negative sequence component and the first voltage error signal (the first voltage error signal includes the first voltage error signal in Axial component U αe1 (s) and the first voltage error signal Axial component U βe1 (s)). Further, the output of the first higher-order decoupling complex filter is used as the input of the second higher-order decoupling complex filter to obtain the first resonant positive-sequence component. First resonant negative sequence component and the second voltage error signal (the second voltage error signal includes the second voltage error signal in the second voltage error signal) Axial component U αe2 (s) and the second voltage error signal Axial component U βe2 (s)). Similarly, the (n-2)th voltage error signal output from the (n-1)th higher-order decoupling complex filter is used as the input to the nth higher-order decoupling complex filter n to obtain the (n-1)th resonant positive sequence component. The (n-1)th resonant negative sequence component Passing the exam Voltage error signal (the first) Voltage error signal includes the first Voltage error signal Axial component U αen (s) and the Voltage error signal Axial component U βen (s)).
[0037] It should be noted that, in this invention, the fundamental positive sequence component... In the fundamental positive sequence component Axial components and the fundamental positive sequence component Axial components The general term; fundamental negative sequence component In the fundamental negative sequence component Axial components and the fundamental negative sequence component Axial components The general term; the first resonant positive sequence component In the first resonant positive sequence component Axial components and the first resonant positive sequence component Axial components The general term; the first resonant negative sequence component In the first resonant negative sequence component Axial components and the first resonant negative sequence component Axial components The general term; the (n-1)th resonant positive sequence component In the (n-1)th resonant positive sequence component Axial components and the (n-1)th resonant positive sequence component Axial components The collective term; the (n-1)th resonant negative sequence component In the (n-1)th resonant negative sequence component Axial components and the (n-1)th resonant negative sequence component Axial components A general term.
[0038] Each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter is used to extract positive-order and negative-order components in each higher-order decoupling complex filter. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter.
[0039] The inputs of the intermediate first-order decoupling complex filters in a higher-order decoupling complex filter are the positive-sequence and negative-sequence components of the output of the previous first-order decoupling complex filter.
[0040] Higher-order decoupling complex filters include higher-order positive-order decoupling complex filters and higher-order negative-order decoupling complex filters. The transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of a first-order positive-order complex filter is obtained, and the transfer function of a higher-order negative-order decoupling complex filter is based on the corresponding... The transfer function of a first-order negative-order complex filter is obtained.
[0041] Figure 2This invention provides a high-order decoupling complex filter, specifically... Figure 2 The diagram shown is the structure of the first high-order decoupling complex filter. Figure 2 In the diagram, the first-order decoupling complex filter 1 is the first-order decoupling complex filter. For the first First-order decoupling complex filter.
[0042] Taking the fundamental frequency as an example, that is, taking the first higher-order decoupling complex filter as an example, the transfer functions of the first-order positive-order complex filter and the first-order negative-order complex filter in the first higher-order decoupling complex filter are Equations (2) and (3), respectively:
[0043] (2)
[0044] (3)
[0045] Among them, F p (s) and F n (s) are the transfer functions of a first-order positive-order complex filter and a first-order negative-order complex filter, respectively; ω c ω1 is the cutoff frequency of the first-order decoupling complex filter, ω1 is the fundamental angular frequency, and s is the complex frequency.
[0046] Although the fundamental positive-sequence filter can accurately detect the positive-sequence component, it cannot completely attenuate the negative-sequence component; similarly, the fundamental negative-sequence filter can accurately detect the negative-sequence component, but it cannot completely attenuate the positive-sequence component. In order to achieve accurate detection of the positive-sequence and negative-sequence components, a cross-decoupling structure is adopted here. The fundamental positive-sequence component and the fundamental negative-sequence component can be calculated using the following equations (4) and (5) using a first-order decoupled complex filter:
[0047] (4)
[0048] (5)
[0049] in, The fundamental positive sequence component is obtained by using a first-order decoupled complex filter. This refers to the fundamental negative sequence component when a first-order decoupled complex filter is used.
[0050] When the three-phase voltage contains only the fundamental positive-sequence and fundamental negative-sequence components, the fundamental frequency can be accurately extracted using a first-order cross-decoupling complex filter. However, if the three-phase voltage contains background harmonics or resonant components, a first-order decoupling complex filter has limited suppression capability for harmonic components of other frequencies and cannot accurately extract the positive-sequence and negative-sequence components. To enhance the suppression capability of the first-order decoupling complex filter for other frequency components, [further steps are needed]. A higher-order decoupling complex filter is obtained by cascading a first-order decoupling complex filter. The transfer functions of the higher-order positive-order decoupling complex filter and the higher-order negative-order decoupling complex filter are Equations (6) and (7), respectively:
[0051] (6)
[0052] (7)
[0053] in, and These are the transfer functions of a higher-order positive-order complex filter and a higher-order negative-order complex filter, respectively. This represents the number of cascaded first-order decoupling complex filters.
[0054] At this point, the positive-sequence component and the negative-sequence component of the output of the first high-order decoupling complex filter are respectively Equation (8) and Equation (9):
[0055] (8)
[0056] (9)
[0057] in, The fundamental positive sequence component of the output of the first higher-order decoupled complex filter when the first higher-order decoupled complex filter is cascaded with multiple first-order decoupled complex filters; The fundamental negative sequence component of the output of the first higher-order decoupled complex filter is given when the first higher-order decoupled complex filter is cascaded with multiple first-order decoupled complex filters.
[0058] By cascading multiple first-order decoupled complex filters, the ability to suppress harmonics at other frequencies is significantly enhanced.
[0059] It should be understood that when a high-order decoupling complex filter employs multiple cascaded first-order decoupling complex filters, the fundamental positive-sequence component and fundamental negative-sequence component output by the first high-order decoupling complex filter are respectively... and When a single first-order decoupling complex filter replaces a higher-order decoupling complex filter (e.g., the first higher-order decoupling complex filter is replaced by a first-order decoupling complex filter), the corresponding output fundamental positive-sequence component and fundamental negative-sequence component are respectively... and .
[0060] Figure 3 A method for implementing a high-order decoupling complex filter is presented. Figure 3 The high-order decoupling complex filter shown is composed of multiple first-order decoupling complex filters cascaded together.
[0061] The following example uses the first first-order decoupling complex filter in the first higher-order decoupling complex filter as an example.
[0062] Since formulas (4) and (5) are expressions for a first-order decoupled complex filter, the expression for the first first-order decoupled complex filter in the first higher-order decoupled complex filter can be derived based on formulas (4) and (5), where the fundamental positive sequence component is in shaft and The components of the axis are given by equations (10) and (11):
[0063] (10)
[0064] (11)
[0065] in, and The fundamental positive-sequence component of the output of the first first-order decoupling complex filter in the first higher-order decoupling complex filter is respectively... shaft and The components of the axis; and The fundamental negative-sequence component of the output of the first first-order decoupling complex filter in the first higher-order decoupling complex filter is respectively... shaft and The components of the axis.
[0066] The fundamental negative sequence component on the α-axis and β-axis are given by equations (12) and (13):
[0067] (12)
[0068] (13)
[0069] According to formulas (10) to (13), the first first-order decoupling complex filter in the first higher-order decoupling complex filter can be realized. The output of the first first-order decoupling complex filter in the first higher-order decoupling complex filter can be used as the input of the subsequent first-order decoupling complex filter. Multiple first-order decoupling complex filters are cascaded to form a higher-order decoupling complex filter.
[0070] The fundamental positive-sequence component of the output of the first-order decoupling complex filter in the first higher-order decoupling complex filter is... shaft and Components of the axis and And the fundamental negative-sequence component of the output of the first first-order decoupling complex filter in the first higher-order decoupling complex filter. shaft and Components of the axis and As the output of the second first-order decoupling complex filter in the first higher-order decoupling complex filter, and so on, the inputs of the intermediate first-order decoupling complex filters in the first higher-order decoupling complex filter are the positive-sequence and negative-sequence components of the output of the previous first-order decoupling complex filter. The output of the first-order negative-sequence complex filter is the fundamental positive-sequence component of the first higher-order decoupling complex filter. The fundamental negative-sequence component of the output of the first higher-order decoupling complex filter .
[0071] The method for detecting wideband oscillation components of cascaded high-order complex filters provided by this invention includes: Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).
[0072] The transfer functions of the first-order positive-sequence complex filter and the first-order negative-sequence complex filter are obtained based on the cutoff frequency of the first-order decoupled complex filter and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output.
[0073] exist In a frequency-locked loop (FLL):
[0074] The first frequency-locked loop (FLL) corresponds to the first higher-order decoupling complex filter, including: based on the fundamental positive-sequence component output by the first higher-order decoupling complex filter... In the shaft component and the first voltage error signal The fundamental angular frequency is obtained from the axial component;
[0075] The second frequency-locked loop (FLL) corresponds to the second higher-order decoupling complex filter, including: based on the first resonant positive-sequence component output by the second higher-order decoupling complex filter... Shaft component and second voltage error signal The first resonant angular frequency is obtained from the axial component;
[0076] No. Frequency Locked Loop (FLL) and the first Higher-order decoupling complex filters correspond to, including: according to the first The first output of a high-order decoupling complex filter In the resonant positive sequence component Axis components and the first Voltage error signal The axis component is obtained as follows Resonant angular frequency.
[0077] The fundamental angular frequency is input to each of the first-order decoupling complex filters in the first higher-order decoupling complex filter, and the first resonant angular frequency is input to each of the first-order decoupling complex filters in the second higher-order decoupling complex filter. The resonant angular frequency is input to the first Each first-order decoupling complex filter in a higher-order decoupling complex filter.
[0078] Among them, in the first voltage error signal The axis components are input to the first higher-order decoupling complex filter. In the axial frequency domain voltage component and the fundamental positive sequence component In the axial components and fundamental negative sequence components The shaft component is calculated; in the second voltage error signal The shaft component is based on the first voltage error signal. Axial components, first resonant positive sequence components In the axial component and the first resonant negative sequence component The axis components are calculated; the first Voltage error signal Axis components according to the first Voltage error signal Axis component, first In the resonant positive sequence component Axis components and the first In the resonant negative sequence component The axial components are calculated.
[0079] Specifically, to achieve frequency adaptation, a frequency-locked loop (FLL) is used. Taking the fundamental frequency as an example, for the first higher-order decoupling complex filter, the first step is to calculate the first voltage error signal... The axial component is given by equation (14):
[0080] (14)
[0081] Among them, U αe1 (s) represents the first voltage error signal. Axial components, In the fundamental positive sequence component of the first higher-order decoupling complex filter output Axial components, In the fundamental negative sequence component of the output of the first higher-order decoupling complex filter Axial components.
[0082] The first voltage error signal In axial components and fundamental positive sequence components The fundamental angular frequency is obtained by multiplying the axial components and then passing the result through an integral controller, as shown in equation (15):
[0083] (15)
[0084] Where K1 is the frequency-locked loop control gain of the first high-order decoupling complex filter. In the fundamental positive sequence component of the first higher-order decoupling complex filter output Axial components.
[0085] Similarly, in order to achieve frequency adaptation of the nth higher-order decoupling complex filter, the nth... The resonant angular frequency is given by equation (16):
[0086] (16)
[0087] Among them, K n Let be the frequency-locked loop control gain of the nth higher-order decoupled complex filter. For the first Voltage error signal Axial components, For the first In the resonant positive sequence component Axial components.
[0088] Among them, the The first output of a high-order decoupling complex filter Voltage error Axial components For equation (17):
[0089] (17)
[0090] in, and These are the fundamental positive sequence components. In the axial components and fundamental negative sequence components Axial components; and These are the first resonant positive sequence components. In the axial component and the first resonant negative sequence component Axial components; and The first In the resonant positive sequence component Axis components and the first In the resonant negative sequence component Axial components.
[0091] The invention will be further illustrated below with specific implementation examples.
[0092] To verify the effectiveness of the broadband oscillation component detection method based on cascaded high-order complex filters of this invention, a simulation model can be built in Matlab / Simulink, for example. The number of cascaded high-order decoupling complex filters is set to 3, and the number of first-order decoupling complex filters is set to 2. Initially, the three-phase voltages are balanced with an amplitude of 1 pu and a frequency of 50 Hz. At 1.0 s, the three-phase voltage frequency abruptly changes from 50 Hz to 45 Hz, and simultaneously, a first example resonant component with an amplitude / frequency of 0.2 pu / 225 Hz and a second example resonant component with an amplitude / frequency of 0.2 pu / 1618 Hz are injected into the three-phase voltages. The simulation results are as follows: Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown. It should be understood that the first and second example resonant components are merely the resonant components used in this embodiment. To make the invention clearer, the first and second example resonant components are used to distinguish different resonant components, and are not intended to limit the invention.
[0093] in, Figure 4 This is the three-phase voltage provided by the present invention; Figure 5 This invention provides The fundamental component and its frequency in the coordinate system, where, Figure 5 (a) in the middle is The fundamental component in the coordinate system, Figure 5 In this context, (b) represents the fundamental frequency; Figure 6 This invention provides The first example resonant component and its frequency in the coordinate system, where... Figure 6 (a) in the middle is The first example resonant component in the coordinate system. Figure 6 In the example, (b) is the frequency of the first example resonant component; Figure 7 This invention provides The second example resonant component and its frequency in the coordinate system, wherein, Figure 7 (a) in the middle is The second example resonant component in the coordinate system. Figure 7 In the example, (b) is the frequency of the second example resonant component.
[0094] Simulation results show that a resonant component exists in the three-phase voltage after 1.0s. Figure 5 , Figure 6 and Figure 7 It can be seen that the broadband oscillation component detection method based on cascaded high-order complex filters proposed in this invention can accurately detect the fundamental component and its frequency, as well as the resonant component and its frequency, while achieving frequency adaptive tracking, thus ensuring the smooth execution of the broadband oscillation damping device suppression algorithm.
[0095] Accordingly, the present invention also provides a wideband oscillation component detection system based on cascaded high-order complex filters. This system includes: a cascaded high-order decoupled complex filter comprising multiple high-order decoupled complex filters and multiple frequency-locked loops (FLLs). The cascaded high-order decoupled complex filter is composed of multiple cascaded high-order decoupled complex filters, and each high-order decoupled complex filter is configured with a frequency-locked loop (FLL). Each high-order decoupled complex filter is composed of multiple cascaded first-order decoupled complex filters, and each first-order decoupled complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter. The input of the cascaded high-order decoupled complex filter is... The frequency domain voltage component in the coordinate system is detected by a cascaded high-order decoupling complex filter to obtain a wideband oscillation component. This wideband oscillation component is the fundamental component and multiple resonant components obtained after successive filtering by multiple high-order decoupling complex filters. The input of each intermediate stage of the cascaded high-order decoupling complex filter is the fundamental or resonant component output by the previous stage of the high-order decoupling complex filter and the voltage error signal.
[0096] Among them, cascaded high-order decoupling complex filters include A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, wherein: the input of the first high-order decoupling complex filter is the input to the cascaded high-order decoupling complex filter. In the frequency domain voltage component of the coordinate system, the output of the first higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first higher-order decoupling complex filter includes the fundamental positive-sequence component and the fundamental negative-sequence component. The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive-sequence component and the first resonant negative-sequence component. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
[0097] Each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter extracts the positive-sequence and negative-sequence components in each higher-order decoupling complex filter. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-sequence complex filter and a first-order negative-sequence complex filter. The input of each intermediate first-order decoupling complex filter in the higher-order decoupling complex filter is the positive-sequence and negative-sequence components output by the previous first-order decoupling complex filter.
[0098] Among them, the higher-order decoupling complex filters include higher-order positive-order decoupling complex filters and higher-order negative-order decoupling complex filters. The transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of a first-order positive-order complex filter is obtained, and the transfer function of a higher-order negative-order decoupling complex filter is based on the corresponding... The transfer functions of the first-order negative-order complex filters are obtained, wherein the transfer functions of the first-order positive-order complex filters and the first-order negative-order complex filters are based on the cutoff frequency of the first-order decoupled complex filters and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output; wherein, the broadband oscillation component detection system also includes Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).
[0099] It should be noted that the specific details and benefits of the broadband oscillation component detection system based on cascaded high-order complex filters provided by this invention are similar to those of the broadband oscillation component detection method based on cascaded high-order complex filters provided by this invention, and will not be repeated here.
[0100] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.
[0101] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.
[0102] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.
Claims
1. A method for detecting broadband oscillation components based on cascaded high-order complex filters, characterized in that, The method includes: Multiple high-order decoupled complex filters are cascaded to form a cascaded high-order decoupled complex filter, and a frequency-locked loop (FLL) is configured in each high-order decoupled complex filter; The input of the cascaded high-order decoupling complex filter is The frequency domain voltage component in the coordinate system is detected by the cascaded high-order decoupled complex filter to obtain a broadband oscillation component. This broadband oscillation component is the fundamental component and multiple resonant components obtained after being filtered successively by multiple high-order decoupled complex filters. The input of each intermediate stage of the cascaded high-order decoupling complex filter is the fundamental or resonant component and voltage error signal output from the previous stage of the high-order decoupling complex filter. Each higher-order decoupling complex filter is composed of multiple cascaded first-order decoupling complex filters, and each first-order decoupling complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter.
2. The broadband oscillation component detection method based on a cascaded high-order complex filter according to claim 1, characterized in that, The cascaded high-order decoupling complex filter includes A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, where: The input to the first higher-order decoupling complex filter is the input to the cascaded higher-order decoupling complex filter. In the coordinate system, the frequency domain voltage component, the output of the first higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first higher-order decoupling complex filter includes the fundamental positive sequence component and the fundamental negative sequence component. The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive sequence component and the first resonant negative sequence component. No. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
3. The broadband oscillation component detection method based on a cascaded high-order complex filter according to claim 2, characterized in that, Each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter is used to extract positive-order and negative-order components in each higher-order decoupling complex filter. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter. The inputs of the intermediate first-order decoupling complex filters of the higher-order decoupling complex filter are the positive-sequence and negative-sequence components of the output of the previous first-order decoupling complex filter.
4. The broadband oscillation component detection method based on a cascaded high-order complex filter according to claim 3, characterized in that, The higher-order decoupling complex filter includes a higher-order positive-order decoupling complex filter and a higher-order negative-order decoupling complex filter. The transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of the first-order positive-order complex filter is obtained, and the transfer function of the higher-order negative-order decoupling complex filter is based on the corresponding... The transfer function of a first-order negative-order complex filter is obtained; The transfer functions of the first-order positive-sequence complex filter and the first-order negative-sequence complex filter are obtained based on the cutoff frequency of the first-order decoupled complex filter and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output.
5. The broadband oscillation component detection method based on a cascaded high-order complex filter according to claim 4, characterized in that, The method includes Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).
6. The broadband oscillation component detection method based on a cascaded high-order complex filter according to claim 5, characterized in that, exist In a frequency-locked loop (FLL): The first frequency-locked loop (FLL) corresponds to the first higher-order decoupling complex filter, including: based on the fundamental positive-sequence component output by the first higher-order decoupling complex filter... In the shaft component and the first voltage error signal The fundamental angular frequency is obtained from the axial component; The second frequency-locked loop (FLL) corresponds to the second higher-order decoupling complex filter, including: based on the first resonant positive-sequence component output by the second higher-order decoupling complex filter... Shaft component and second voltage error signal The first resonant angular frequency is obtained from the axial component; No. Frequency Locked Loop (FLL) and the first Higher-order decoupling complex filters correspond to, including: according to the first The first output of a high-order decoupling complex filter In the resonant positive sequence component Axis components and the first Voltage error signal The axis component is obtained as follows Resonant angular frequency; Wherein, the fundamental angular frequency is input to each first-order decoupling complex filter in the first higher-order decoupling complex filter, and the first resonant angular frequency is input to each first-order decoupling complex filter in the second higher-order decoupling complex filter. The resonant angular frequency is input to the first Each first-order decoupling complex filter in a higher-order decoupling complex filter; Among them, in the first voltage error signal The axis components are input to the first higher-order decoupling complex filter. In the axial frequency domain voltage component and the fundamental positive sequence component In the axial components and fundamental negative sequence components The shaft component is calculated; in the second voltage error signal The shaft component is based on the first voltage error signal. Axial components, first resonant positive sequence components In the axial component and the first resonant negative sequence component The axis components are calculated; the first Voltage error signal Axis components according to the first Voltage error signal Axis component, first The α-axis component and the first harmonic positive sequence component The α-axis component of the resonant negative sequence component is calculated.
7. A broadband oscillation component detection system based on a cascaded high-order complex filter, characterized in that, The system includes: A cascaded high-order decoupled complex filter includes multiple high-order decoupled complex filters and multiple frequency-locked loops (FLLs). The cascaded high-order decoupled complex filter is composed of multiple high-order decoupled complex filters cascaded together, and each high-order decoupled complex filter is equipped with a frequency-locked loop (FLL). Each higher-order decoupling complex filter is composed of multiple first-order decoupling complex filters cascaded together. Each first-order decoupling complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter. The input of the cascaded high-order decoupling complex filter is... The frequency domain voltage component in the coordinate system is detected by the cascaded high-order decoupling complex filter to obtain a wideband oscillation component. This wideband oscillation component is the fundamental component and multiple resonant components obtained after successive filtering by multiple high-order decoupling complex filters. The input of the intermediate stages of the cascaded high-order decoupling complex filter is the fundamental or resonant component output by the previous stage of the high-order decoupling complex filter and the voltage error signal.
8. The broadband oscillation component detection system based on a cascaded high-order complex filter according to claim 7, characterized in that, The cascaded high-order decoupling complex filter includes A series of high-order decoupling complex filters, namely the first to the second... A high-order decoupling complex filter, where: The input to the first higher-order decoupling complex filter is the input to the cascaded higher-order decoupling complex filter. In the coordinate system, the frequency domain voltage component, the output of the first higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The fundamental component of the output of the first higher-order decoupling complex filter includes the fundamental positive sequence component and the fundamental negative sequence component. The input of the second higher-order decoupling complex filter is the fundamental component and the first voltage error signal. The output of the second higher-order decoupling complex filter is the first resonant component and the second voltage error signal. The first resonant component includes the first resonant positive sequence component and the first resonant negative sequence component. No. The input of a higher-order decoupling complex filter is the first... The first output of a high-order decoupling complex filter Resonant components and the first Voltage error signal, number The output of the higher-order decoupling complex filter is the first Resonant components and the first Voltage error signal, where are positive integers and , No. The resonant components include the first The resonant positive sequence component and the first Resonant negative sequence component.
9. The broadband oscillation component detection system based on a cascaded high-order complex filter according to claim 8, characterized in that, Each high-order decoupling complex filter includes There are three first-order decoupling complex filters, namely the first to the second. A first-order decoupling complex filter is used to extract positive-order and negative-order components in each higher-order decoupling complex filter. The first-order decoupling complex filter is a first-order cross-decoupling complex filter, and each first-order decoupling complex filter includes a first-order positive-order complex filter and a first-order negative-order complex filter. The inputs of the intermediate first-order decoupling complex filters of the higher-order decoupling complex filter are the positive-sequence and negative-sequence components of the output of the previous first-order decoupling complex filter.
10. The broadband oscillation component detection system based on a cascaded high-order complex filter according to claim 9, characterized in that, The higher-order decoupling complex filter includes a higher-order positive-order decoupling complex filter and a higher-order negative-order decoupling complex filter. The transfer function of the higher-order positive-order decoupling complex filter is based on the corresponding... The transfer function of the first-order positive-order complex filter is obtained, and the transfer function of the higher-order negative-order decoupling complex filter is based on the corresponding... The transfer functions of the first-order negative-order complex filters are obtained, where the transfer functions of the first-order positive-order complex filters and the first-order negative-order complex filters are based on the cutoff frequency of the first-order decoupled complex filters and the fundamental or resonant angular frequency of the corresponding frequency-locked loop (FLL) output. The broadband oscillation component detection system also includes Each frequency-locked loop (FLL) is connected to... Each high-order decoupling complex filter corresponds one-to-one with the frequency-locked loop (FLL) based on the voltage error signal. In the axial components and fundamental positive sequence components or resonant positive sequence components The axial components are used to obtain the corresponding fundamental or resonant angular frequencies, and these frequencies are then input to the corresponding higher-order decoupled complex filters so that each higher-order decoupled complex filter can achieve frequency adaptation through a frequency-locked loop (FLL).