Universal selective harmonic repetitive controller and feedback control system

Abstract

The invention discloses a universal selective harmonic repetitive controller and a feedback control system, and belongs to the field of harmonic repetitive controllers. The device is composed of two time delay modules and a positive feed-forward gain module, has an independent delay link on a forward channel and has an output positive feedback form, and can realize accurate and rapid control of harmonic waves with specified times; the suppression of the harmonic waves with specified times in different application scenes can be realized by configuring different parameters; the cascade form and the fractional order expansion form of the periodic signal generator can be simplified at the same time, and under the condition of the same gain, better control performance and faster control speed are achieved. Besides, the frequency fluctuation configuration expansion form parameters can be sampled through a phase-locked loop, so that the frequency adaptive selection harmonic repetitive controller forms repetitive controllers with different internal model parameters and has different transfer functions, the universality is high, the application range is wide, the flexibility is high, and the use requirements of different application occasions can be met.

Description

Technical Field

[0001] The invention relates to a universal selective harmonic repetitive controller and a feedback control system, belonging to the field of harmonic repetitive controllers. Background Art

[0002] In today's era of pursuing carbon neutrality and carbon peak, actively advancing progress toward these goals is of paramount strategic importance. Building a new power system dominated by renewable energy sources is a key component in achieving this goal. Renewable energy sources such as wind and solar power, due to their clean, environmentally friendly, and renewable nature, play a dominant role in the construction of new power systems. However, when these renewable energy sources are connected to the grid, a series of issues arise that impact power system stability. For example, they can cause system frequency fluctuations and lead to voltage asymmetry. These instabilities can cause periodic harmonics to interfere with the voltage and current waveforms of the power system, severely impacting the performance of related controllers and posing a potential threat to the safe and stable operation of the power system.

[0003] The control performance of power systems depends largely on how effectively they control periodic signals. Taking three-phase / single-phase grid-connected converters as an example, their actual output signals contain not only harmonics of specific frequencies, such as the fourth and sixth harmonics, but also other harmonic components that are not specific multiples of the power frequency, as well as higher-order harmonics. The presence of these harmonics increases the difficulty of precise control. However, repetitive control technology based on the internal model principle can achieve high-precision, error-free tracking of periodic signals of various frequencies under steady-state conditions, or effectively eliminate these periodic interference signals. This provides strong technical support and solutions for ensuring the stable and efficient operation of power systems, and plays a key role in promoting the intelligent construction and sustainable development of new power systems.

[0004] To eliminate errors in specified subharmonics in converter control systems, scholars and researchers in related fields have proposed a variety of subharmonic repetitive control schemes. For example, Wenzhou Lu et al. proposed the nk±m subharmonic repetitive controller (Lu W, Zhou K, Wang D, et al. A Generic Digital $nk pm m$-Order Harmonic Repetitive Control Scheme for PWM Converters[J]. IEEE Transactions on Industrial Electronics, 2014, 61(3): 1516-1527. DOI: 10.1109 / TIE.2013.2258295.). Patent CN111142389B, "A Customized Harmonic Repetitive Controller and Control Method," and Patent CN115657460A, "A Customized Harmonic Repetitive Controller," propose similar control technologies that can effectively eliminate errors in specified subharmonics. However, existing subharmonic repetitive controllers generally have complex structural technical problems, which makes them difficult to design, implement and expand in practice, and makes it difficult to meet the requirements of conversion control systems for control algorithm simplicity, reliability and scalability. Summary of the Invention

[0005] In order to meet the requirements of the conversion control system for control algorithm simplicity, reliability and scalability, the present invention provides a universal selective harmonic repetitive controller and feedback control system. The technical solution is as follows:

[0006] The first object of the present invention is to provide a universal selective harmonic repetitive controller, comprising: a repetitive control gain module, a first adding loop U1 and a periodic signal generator;

[0007] The input end of the repetitive control gain module is connected to the input end of the universal selective harmonic repetitive controller, and the output end is connected to a positive input end of the first adding loop U1; the output end of the first adding loop U1 is connected to the input end of the periodic signal generator; the output end of the periodic signal generator is respectively connected to the other positive input end of the first adding loop U1 and the output end of the universal selective harmonic repetitive controller;

[0008] The periodic signal generator includes: a subtraction loop U0, a first time delay module τ1, a second addition loop U2, and a second time delay module τ2. The input end of the periodic signal generator is connected to a negative input end of the subtraction loop U0 and is connected to the positive input end of the second addition loop U2 through a gain module; the output end of the subtraction loop U0 is connected to the input end of the first time delay module τ1; the output end of the first time delay module τ1 is connected to the positive input end of the second addition loop U2; the output end of the second addition loop U2 is connected to the input end of the second time delay module τ2 and is connected to the positive input end of the subtraction loop U0 through a gain module, and the output end of the second time delay module τ2 is connected to the output end of the periodic signal generator.

[0009] Optionally, the output end of the first time delay module τ1 is connected to the second adding loop U2 through a first low-pass filter, and the output end of the second time delay module τ2 is connected to the output end of the periodic signal generator through a second low-pass filter.

[0010] Optionally, the first low-pass filter is connected to the second adding ring U2 via a first fractional-order filter, and the second low-pass filter is connected to the output end of the periodic signal generator via a second fractional-order filter.

[0011] Optionally, the output end of the periodic signal generator is connected to the output end of the universal selective harmonic repetitive controller through a phase advance compensator.

[0012] The second object of the present invention is to provide a parallel multi-channel universal selective harmonic repetitive controller, comprising several parallel universal selective harmonic repetitive controllers as described in any one of the above items and a third adding ring U3; the input end of each universal selective harmonic repetitive controller is connected to the input end of the parallel multi-channel universal selective harmonic repetitive controller, and the output end is respectively connected to the positive input end of the third adding ring U3; the output end of the third adding ring U3 is connected to the output end of the parallel multi-channel universal selective harmonic repetitive controller.

[0013] Optionally, the output end of the third adding loop U3 is connected to the output end of the universal selective harmonic repetitive controller through a phase lead compensator.

[0014] A third object of the present invention is to provide a cascaded multi-order selection universal harmonic repetitive controller, comprising a repetitive control gain module, a first adding loop U1, an L-stage cascaded periodic signal generator, and a fourth adding loop U4; the periodic signal generator is the periodic signal generator described above;

[0015] The input end of the repetitive control gain module is connected to the input end of the universal selective harmonic repetitive controller, and the output end is connected to a positive input end of the first adding loop U1;

[0016] The input end of the first-order periodic signal generator H1(z) is connected to the output end of the first adding loop U1. Starting from the second-order periodic signal generator, any l-th-order periodic signal generator H l The input of (z) is connected to the l-1 order periodic signal generator H l-1 (z) output terminal, any l-th order signal generator H l The output of (z) is extended by a universal expansion factor M l A positive input end of the fourth adding ring U4 is connected, and an output end of the fourth adding ring U4 is respectively connected to the positive input end of the first adding ring U1 and the output end of the cascaded multi-order selective harmonic repetitive controller.

[0017] Optionally, the output ends of the time delay modules in the periodic signal generator are connected to the next device through a fractional-order filter.

[0018] A fourth object of the present invention is to provide a fractional-order composite high-order parallel universal selective harmonic repetitive controller, characterized in that it includes the universal selective harmonic repetitive controller as described above and the cascaded multi-order selective harmonic repetitive controller as described above, and the universal selective harmonic repetitive controller and the cascaded multi-order selective harmonic repetitive controller are combined in parallel to form a composite controller.

[0019] The fifth object of the present invention is to provide a feedback control system, comprising a subtraction loop U5, a universal selective harmonic repetitive controller G as described in any one of the above items. rc (z), sixth addition ring U6, seventh addition ring U7;

[0020] The positive input terminal of the subtraction loop U5 is connected to the input terminal of the feedback control system to obtain the reference input signal i ref (z), the negative input end is connected to the output end of the feedback control system to obtain the actual output signal i(z), and the output end is respectively connected to the universal selective harmonic repetitive controller G rc (z) input end and a positive input end of the sixth adding loop U6; the universal selective harmonic repetitive controller G rc The output end of (z) is connected to the other positive input end of the sixth adding ring U6; the output end of the sixth adding ring U6 is connected to the traditional feedback controller G c (z) input terminal; the traditional feedback controller G c The output terminal of (z) is connected to the control object G p (z) input terminal; the control object G pThe output end of (z) is connected to a positive input end of the seventh adding loop U7; the other positive input end of the seventh adding loop U7 is connected to the system disturbance input d(z), and the output end is connected to the output end of the feedback control system.

[0021] The beneficial effects of the present invention are:

[0022] The present application discloses a universal selective harmonic repetitive controller, which consists of a forward channel with a simple structure of two time delay modules and a positive feedforward gain module, and has an independent time delay module on the forward channel, so that the universal selective harmonic repetitive controller is simpler when forming the structure of the L-order signal generator cascade to further optimize the control performance, especially when the fundamental frequency changes, it can also show good harmonic suppression ability and fast performance. In addition, the universal selective harmonic repetitive controller has an output positive feedback form, so that the universal selective harmonic repetitive controller conforms to the standard internal model structure, and can achieve accurate and rapid control of harmonics of specified orders. The controller has a simple and beautiful structure and is easy to design. By configuring different n and m parameters, the suppression of harmonics of specified orders in different application scenarios can be achieved. Therefore, in k rc Under the same circumstances, it can have a faster control speed.

[0023] Furthermore, the forward channel of the universal selective harmonic repetitive controller of the present invention can be constructed using two identical digital time delay modules connected in parallel, significantly reducing the total number of memory cells required for its hardware implementation. Therefore, the controller has a clear advantage in terms of storage resource utilization. While maintaining the dynamic performance of rapidly eliminating periodic disturbance errors, the controller can achieve precise and rapid tracking and suppression of specific harmonic components in the power system through programmable parameter configuration, significantly improving its versatility and flexibility compared to traditional solutions.

[0024] This universal selective harmonic repetitive controller can be further expanded to form a multi-control channel parallel structure, and can flexibly achieve effective elimination of all or specified harmonics, and can independently adjust the control gain parameters of each harmonic to further optimize the system control performance and dynamic response characteristics.

[0025] The universal selective harmonic repetitive controller can further be equipped with a built-in fractional-order filter. When a traditional repetitive controller faces fundamental frequency fluctuations, the period parameter N in the repetitive controller will be a non-integer, which seriously affects the control performance of the repetitive controller. Therefore, the universal selective harmonic repetitive controller can be equipped with a built-in fractional-order filter to improve the harmonic suppression capability of the repetitive controller.

[0026] The universal selective harmonic repetitive controller can further have a built-in low-pass filter to improve robustness, and can further have a built-in phase advance compensator or make the time delay module controlled by the time delay damping coefficient to compensate for the phase lag caused by the control object and the low-pass filter, improve the stability of the controller, and further optimize the control performance of the universal selective harmonic repetitive controller.

[0027] This universal selective harmonic repetitive controller can also be combined with a higher-order method and a fractional-order filter to form a frequency-adaptive selective harmonic repetitive controller by dynamically adjusting parameters. This frequency-adaptive selective harmonic repetitive controller has high versatility, a wide range of applications, high flexibility, and strong robustness, adapting to the needs of different applications.

[0028] The universal selective harmonic repetitive controller can constitute a frequency adaptive selective harmonic repetitive controller. By configuring different universal expansion coefficients, the frequency adaptive selective harmonic repetitive controller can form a repetitive controller with different expansion modes and different transfer functions. Then, by configuring different n and m parameters, the suppression of (nk±m) subharmonics in different application scenarios can be achieved. Therefore, in k rc Under the same circumstances, it can have a faster control speed. The frequency adaptive selection harmonic repetitive controller has high versatility, wide application range, high flexibility and strong robustness, and can meet the needs of different application occasions.

[0029] The frequency adaptive selection harmonic repetitive controller forms repetitive controllers with different expansion modes through different combinations of expansion coefficients, which all conform to the standard internal model structure and can achieve accurate and rapid control of harmonics of specified orders. The controller has a simple and beautiful structure, is easy to design, and occupies fewer memory units. Especially when the fundamental frequency changes, it can also show good harmonic suppression capability and fast performance.

[0030] The controller can further have a built-in low-pass filter unit with adjustable parameters to improve the system's anti-interference robustness. At the same time, it can also selectively have a built-in phase advance compensator module or make the time delay module controlled by an adjustable time delay damping coefficient to accurately compensate for the phase lag effect caused by the control object and the low-pass filter unit, significantly improving the dynamic stability of the controller, thereby further optimizing the steady-state and transient control performance of the frequency adaptive selective harmonic repetitive controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 1 is a structural diagram of a universal selective harmonic repetitive controller in a continuous-time system in Example 1 of the present invention.

[0033] Figure 2 4 is a structural diagram of a universal selective harmonic repetitive controller in a discrete-time system in Example 1 of the present invention.

[0034] Figure 3 4 is a structural diagram of a universal selective harmonic repetitive controller in Example 2 of the present invention.

[0035] Figure 4 4 is a structural diagram of a universal selective harmonic repetitive controller in Example 3 of the present invention.

[0036] Figure 5 4 is a structural diagram of a parallel multi-channel universal selective harmonic repetitive controller in Example 4 of the present invention.

[0037] Figure 6 4 is a structural diagram of a parallel multi-channel universal selective harmonic repetitive controller in Example 5 of the present invention.

[0038] Figure 7 This is a structural diagram after a fractional-order filter is added to Example 5 of the present invention.

[0039] Figure 8 This is a structural diagram of a cascaded multi-order selection universal harmonic repetitive controller in Example 6 of the present invention.

[0040] Figure 9 1 is a structural diagram after a fractional-order filter is added to Example 6 of the present invention.

[0041] Figure 10 4 is a structural diagram of a universal harmonic repetitive controller when L=2 in Example 6 of the present invention.

[0042] Figure 11 4 is a structural diagram of a universal harmonic repetitive controller in Example 7 of the present invention.

[0043] Figure 12 4 is a structural diagram of the frequency adaptive selective harmonic repetitive controller in Example 8 of the present invention.

[0044] Figure 13 4 is a structural diagram of a fractional-order composite high-order parallel frequency adaptive selective harmonic repetitive controller in Example 9 of the present invention.

[0045] Figure 14 1 is a structural diagram of the feedback control system in Example 10 of the present invention.

[0046] Figure 15A It is the FFT analysis waveform of the steady-state output current of the feedback control system when n=6 and m=1.

[0047] Figure 15B It is the error convergence diagram of the feedback control system when n=6 and m=1.

[0048] Figure 16A It is the FFT analysis waveform of the steady-state output current of the feedback control system when n=6, m=1, and L=2.

[0049] Figure 16B It is the error convergence diagram of the feedback control system when n=6, m=1, and L=2.

[0050] Figure 17A This is the FFT analysis waveform of the steady-state output current when the grid frequency suddenly changes from 50 Hz to 50.5 Hz and there is no built-in fractional-order filter.

[0051] Figure 17B This is the error convergence diagram when the grid frequency suddenly changes from 50 Hz to 50.5 Hz without a built-in fractional-order filter.

[0052] Figure 18A This is the FFT analysis waveform of the steady-state output current when the grid frequency suddenly changes from 50Hz to 50.5Hz and a fractional-order filter is built in.

[0053] Figure 18B This is the error convergence diagram when the grid frequency suddenly changes from 50Hz to 50.5Hz and the fractional-order filter is built in.

[0054] Figure 19A This is the FFT analysis waveform of the steady-state output current when the fundamental frequency fluctuation range is 0.2Hz, M1>1, M2<0, M1+M2=1, and the fractional-order parameters are not adjusted in real time.

[0055] Figure 19B This is the error convergence change diagram when the fundamental frequency fluctuation range is 0.2Hz, M1>1, M2<0, M1+M2=1, and the fractional-order parameters are not adjusted in real time.

[0056] Figure 20A This is the FFT analysis waveform of the steady-state output current when the fractional-order parameters are adjusted in real time when the fundamental frequency fluctuation range is 1 Hz and M1 = 1 and M2 = 0 are configured.

[0057] Figure 20BThis is a graph showing the error convergence change when adjusting the fractional-order parameters in real time when the fundamental frequency fluctuation range is 1 Hz and M1 = 1 and M2 = 0 are configured.

[0058] Figure 21A This is a steady-state current FFT analysis waveform diagram of the fractional-order composite high-order parallel frequency adaptive selective harmonic repetitive controller of the present invention.

[0059] Figure 21B It is an error convergence waveform diagram of the fractional-order composite high-order parallel frequency adaptive selective harmonic repetitive controller of the present invention. DETAILED DESCRIPTION

[0060] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0061] Example 1:

[0062] This embodiment provides a general selective harmonic repetitive controller. Figure 1 The universal selective harmonic repetitive controller includes a repetitive control gain module, a first adding loop U1 and a periodic signal generator H(s). The input end of the repetitive control gain module is connected to the input end of the universal selective harmonic repetitive controller to obtain the error input e(s). The output end of the repetitive control gain module is connected to a positive input end of the first adding loop U1. The output end of the first adding loop U1 is connected to the input end of the periodic signal generator H(s). The output end of the periodic signal generator H(s) is connected to the other positive input end of the first adding loop U1. The output end of the periodic signal generator H(s) is also connected to the output end of the universal selective harmonic repetitive controller to output c(s).

[0063] In the periodic signal generator H(s): the input end of the periodic signal generator H(s) is connected to a negative input end of the subtraction loop U0, and is connected to the positive input end of the second addition loop U2 through a gain module; the output end of the subtraction loop U0 is connected to the input end of the first time delay module τ1; the output end of the first time delay module τ1 is connected to the positive input end of the second addition loop U2; the output end of the second addition loop U2 is connected to the input end of the second time delay module τ2, and is connected to the positive input end of the subtraction loop U0 through a gain module; the output end of the second time delay module τ2 is connected to the output end of the periodic signal generator H(s).

[0064] Among them, the gain achieved by the repeated control gain module on the input is k rc The first time delay module delays the input After the output, the second time delay module delays the input After the output, the gain achieved by the positive feedforward gain module is cos(2πm / n).

[0065] In a continuous-time system, the transfer function of the periodic signal generator H(s) is:

[0066]

[0067] therefore Figure 1 In the example, the transfer function of the general selective harmonic repetitive controller is:

[0068]

[0069] Among them, T0 is the fundamental wave period, f0 is the fundamental frequency, ω0 is the fundamental angular frequency, e is the natural base, s is the s-plane parameter, n, m, k are integers not less than zero, and n ≠ 0 and n > m.

[0070] When m≠0, the above transfer function can be transformed into:

[0071]

[0072] When m=0, it can be simplified to the following form:

[0073]

[0074] According to the above two formulas, the general type selects the G of the harmonic repetitive controller rc The extreme point of (s) is still located at ±j(nk±m)ω0, where k=0,1,2…. Therefore G rc The amplitude-frequency response of (s) is infinite at the (nk±m)th harmonic frequency, so different values ​​of n and m can be selected to achieve accurate elimination of different harmonics. Therefore, by selecting appropriate values ​​of n and m, the universal selective harmonic repetitive controller is used to achieve tracking and elimination of (nk±m)th harmonics.

[0075] In practical applications, the universal selective harmonic repetitive controller is usually designed and implemented in digital form. Figure 1 The digital form of the general type selected harmonic repetitive controller is as follows Figure 2 As shown, its transfer function is:

[0076]

[0077] Wherein, c(z) is the output of the universal selective harmonic repetitive controller, e(z) is the error input of the universal selective harmonic repetitive controller, H(z) is the digital form of the periodic signal generator, is the period parameter, T s is the sampling period, and z is the z-plane parameter.

[0078] The universal selective harmonic repetitive controller includes two time delay modules, and the number of memory cells occupied is Therefore, the total memory occupied by the general selective harmonic repetitive controller is Therefore, the storage space occupied is much less than that of the conventional repetitive controller and the repetitive controller mentioned by previous scholars. Therefore, the special harmonic repetitive controller proposed in the present invention can have a faster response speed and has the advantages of simple and fast design.

[0079] In practical applications, parameters n and m can be assigned different values ​​to meet the needs of different scenarios, thereby achieving error-free tracking or disturbance suppression of specified (nk±m) harmonics. For example, in the case of a three-phase converter with a three-phase rectifier load, since its harmonics are primarily concentrated at the (6k±l)-order (i.e., 5th, 7th, 11th, 13th, etc.) harmonic frequency components, and tracking of the fundamental reference signal is often required, simply setting n = 6 and m = 1 can achieve error-free tracking of the fundamental reference signal and complete elimination of the (6k±l)-order harmonics. In the case of a single-phase converter with a single-phase rectifier load, since its harmonics are primarily concentrated at the (4k±l)-order (i.e., 3rd, 5th, 7th, 9th, etc.) frequency components, and tracking of the fundamental reference signal is often required, simply setting n = 4 and m = 1 can achieve error-free tracking of the fundamental reference signal and complete elimination of odd harmonics.

[0080] Example 2:

[0081] This embodiment is based on the structure of the universal selective harmonic repetitive controller described in Example 1. In order to further improve the robustness of the universal selective harmonic repetitive controller in practical applications, a low-pass filter Q(z) is added. In order to compensate for the phase lag caused by the controlled object and the low-pass filter Q(z) and improve the stability of the controller, a phase lead compensator G can also be added to the universal selective harmonic repetitive controller. f (z), or the time delay module is controlled by the time delay damping coefficient K.

[0082] In actual application, only the robustness of the general selective harmonic repetitive controller can be optimized, or only the stability can be optimized. However, more commonly, since both robustness and stability are important parameter indicators, this embodiment takes the simultaneous optimization of the robustness and stability of the general selective harmonic repetitive controller as an example.

[0083] like Figure 3As shown, in the periodic signal generator H(z), the first time delay module is provided with a time delay damping coefficient K, and its output is connected to the second adding loop U2 through the first low-pass filter Q(z). The second time delay module is also provided with a time delay damping coefficient K, and its output is connected to the output of the periodic signal generator H(z) through the second low-pass filter Q(z). The output of the periodic signal generator H(z) is also connected to the output of the periodic signal generator H(z) through the phase advance compensator G f (z) Connect to the output terminal of the universal selected harmonic repetitive controller.

[0084] In this embodiment, the delay achieved by the two time delay modules can still be z -N / n .

[0085] Figure 3 The universal digital selective harmonic repetitive controller shown can also be implemented in analog form, and the structures in other subsequent embodiments can also be implemented in analog form.

[0086] If not mentioned later, the default time delay damping coefficient K = 1. Figure 3 In the structure shown, the transfer function of the general selected harmonic repetitive controller is:

[0087]

[0088] Example 3:

[0089] like Figure 4 As shown, in this embodiment, based on embodiment 2, the first low-pass filter Q(z) in the periodic signal generator H(z) is further connected to the second adding ring U2 via the first fractional-order filter F(z), and the second low-pass filter Q(z) is further connected to the output end of the periodic signal generator H(z) via the second fractional-order filter F(z).

[0090] exist Figure 2 The situation of adding F(z) to the structure is similar.

[0091] based on Figure 4 The transfer function of the general selective harmonic repetitive controller is:

[0092]

[0093] When the power grid presents a non-ideal state of frequency fluctuation, the grid-side fundamental frequency suddenly changes from an integer N to a non-integer N′. Figure 4 The structure shown can achieve accurate adjustment and approximation of N' in real time and online. FIR filter and IIR filter are two different fractional order compensation schemes.

[0094] The FIR filter based on Lagrange interpolation can effectively achieve approximate compensation for d. Its basic expression is:

[0095]

[0096] as well as:

[0097]

[0098] Where M is the order of the FIR filter, i = 0, 1, 2, ... M. In a non-ideal power grid with grid-side frequency fluctuations, it is necessary to track and calculate the filter coefficients in real time to maintain optimal control performance.

[0099] As another fractional-order approximation compensation scheme, the IIR all-pass filter has the following transfer function:

[0100]

[0101] Among them, the coefficient a n Calculated by Thiran formula, its expression is:

[0102]

[0103] Wherein, k=0, 1, 2, ...M, and M is the filter order.

[0104] After adding the fractional-order filter F(z), the universal selective harmonic repetitive controller can effectively solve the problem of mismatch between the internal model of the repetitive controller and the resonance point of the specified periodic signal at the response frequency when the fundamental frequency changes suddenly. The fractional-order filter F(z) can effectively compensate for the fractional part of the periodic parameter N of the repetitive controller, further improving the stability and robustness of the control system.

[0105] Example 4:

[0106] This embodiment further expands the single control channel control structure described in embodiments 1 to 3 to form a structure with multiple control channels in parallel, such as Figure 5As shown, the universal selective harmonic repetitive controller includes p+1 control channels and a third adding loop U3, each control channel includes a repetitive control gain module and a periodic signal generator H(z), the input end of the repetitive control gain module in each control channel is connected to the input end of the universal selective harmonic repetitive controller to obtain e(z), the output end of the repetitive control gain module in each control channel is respectively connected to the input end of the periodic signal generator H(z) in the control channel, the output end of the periodic signal generator H(z) in each control channel is respectively connected to a positive input end of the third adding loop U3, the output end of the third adding loop U3 is connected to the output end of the universal selective harmonic repetitive controller, and the third adding loop U3 adds the output amounts of each control channel and outputs c(z) at the output end.

[0107] In this embodiment, p=m, such as Figure 5 As shown in the figure, the universal selective harmonic repetitive controller includes m+1 control channels, which are respectively recorded as control channel 0 to control channel p. The structure of each control channel is the same as Figure 2 The structure shown is similar, but the gain achieved by the repeated control gain module in each control channel is different. The gain achieved by the repeated control gain module in any i-th control channel is In addition, the delays realized by the two time delay modules in the periodic signal generator H(z) included in each control channel are However, the gains achieved by the positive feedforward gain modules in each control channel are different. The periodic signal generator H contained in any i-th control channel i The gain achieved by the positive feedforward gain module of (z) is cos(2πm i / n i ). i is a parameter. In this embodiment, since p=m, i is a parameter and i∈[0,m]. Figure 5 In the structure shown, the transfer function of the general selective harmonic repetitive controller is:

[0108]

[0109] Among them, n and m are both positive integers, and when n is an even number, m∈[0,n / 2]; when n is an odd number, m∈[0,[n / 2]], [n / 2] represents rounding n / 2. By selecting different n and m, this universal selective harmonic repetitive controller can be used to eliminate all subharmonics.

[0110] The universal selective harmonic repetitive controller can be used to eliminate the specified harmonics and has an independent adjustment function for the gain of each harmonic, that is, the control gain of each harmonic can be adjusted independently. Figure 5The multi-control channel parallel structure shown can further improve the robustness and stability of the universal selective harmonic repetitive controller.

[0111] Example 5:

[0112] Based on Example 4, this embodiment improves the robustness and stability of the universal selective harmonic repetitive controller by adding a time delay damping coefficient, a low-pass filter and a phase advance compensator. Figure 6 shown.

[0113] The delay of the two time delay modules in the i-th control channel is controlled by the time delay damping coefficient K. The periodic signal generator H in any i-th control channel i The first time delay module (z) is provided with a time delay damping coefficient K, and its output is passed through a low-pass filter Q i (z) Connect the second adding loop U2, the second time delay module also has a time delay damping coefficient K, and its output is passed through another low-pass filter Q i (z) Connect the periodic signal generator H i (z) output terminal. And the output terminal of the third adding loop U3 passes through the phase advance compensator G f (z) is connected to the output terminal of the universal selective harmonic repetitive controller to output c(z). The transfer function of the universal selective harmonic repetitive controller of this embodiment is:

[0114]

[0115] In addition, you can also follow Figure 4 Add a fractional order filter F(z) to each control channel in the following way, the structure is as follows Figure 7 shown.

[0116] Example 6:

[0117] This embodiment is expanded in each control channel and cascades several order signal generators H(z), such as Figure 8 As shown, an L-order signal generator H(z) is provided between the output end of the first adding ring U1 and the input end of the fourth adding ring U4. The input end of the first-order signal generator H1(z) is connected to the output end of the first adding ring U1. Starting from the second-order signal generator, any l-th-order signal generator H l The input of (z) is connected to the l-1 order signal generator H l-1 (z) is the output terminal, l is a parameter and l∈[1,L]. Any l-th order signal generator H l The output of (z) is passed through a first universal expansion factor M lConnected to a positive input terminal of the fourth adding loop U4, the output terminal of the fourth adding loop U4 is connected to the output terminal of the universal selective harmonic repetitive controller and the other positive input terminal of the first adding loop U1. Figure 2 The transfer functions of the various order signal generators H(z) described in the previous section can be expressed as follows based on the transfer functions of the various order signal generators H(z):

[0118]

[0119] exist Figure 8 Based on the multi-order signal generator H(z) cascade structure shown, the robustness and stability of the universal selective harmonic repetitive controller can also be further improved by adding a time delay damping coefficient, a low-pass filter and a phase advance compensator.

[0120] Figure 9 The embodiment shown in Figure 8 On this basis, a fractional-order filter is added to the multi-order signal generator H(z) to approximate the fractional-order delay parameters, which makes full use of the cascaded multi-order form and the fractional-order approximation idea to improve the frequency adaptability of the system.

[0121] The more the order L of the cascaded periodic signal generator is, the faster the control response of the general harmonic repetitive controller can be, thus achieving better control performance. However, this also leads to a greater design complexity. In order to balance the two aspects of performance, it is generally Figure 10 As shown, L=2, so the transfer function of the universal selective harmonic repetitive controller can be expressed based on the transfer function of each order periodic signal generator H(z):

[0122]

[0123] Example 7:

[0124] like Figure 11 As shown, this embodiment improves robustness and stability by adding a time delay damping coefficient, a low-pass filter and a phase advance compensator on the basis of Example 6. In the figure, the output end of the second adding loop U2 is connected to the negative input end of the third subtracting loop U3 through the second time delay module τ2. The output end of the third subtracting loop U3 is connected to the positive input end of the fourth adding loop U4 through another first time delay module τ1. The output end of the fourth adding loop U4 is connected to the positive input end of the fifth adding loop U5 through the second time delay module τ2 and the second universal expansion coefficient M2 in sequence. The other positive input end of the fifth adding loop U5 is connected by the output end of the first-order signal generator H1(z) through the first universal expansion coefficient M1. The output end of the fifth adding loop U5 is connected to the positive input end of the fifth adding loop U5 through the low-pass filter Q(z) and the phase advance compensator G f(z) is connected to the output terminal of the universal selective harmonic repetitive controller to output c(z). The output terminal of the low-pass filter Q(z) is connected to the other positive input terminal of the first adding loop U1. In this embodiment, the transfer function of the universal selective harmonic repetitive controller is:

[0125]

[0126] Will Figure 10 、 Figure 11 and Figure 3 By comparison, it can be seen that when multiple signal generators are cascaded, the cascaded multiple signal generators can share a low-pass filter without the need for Figure 3 Similarly, a low-pass filter is built into each order periodic signal generator, thereby effectively reducing the structural complexity.

[0127] Example 8:

[0128] This embodiment provides a frequency adaptive selective harmonic repetitive controller, such as Figure 12 As shown, the frequency adaptive selective harmonic repetitive controller includes: a repetitive control gain module, a first adding loop U1, a fifth adding loop U5 and periodic signal generators H1(z) and H2(z).

[0129] The input end of the repetitive control gain module is connected to the input end of the frequency adaptive selection harmonic repetitive controller to obtain e(z), the output end of the repetitive control gain module is connected to a positive input end of the first adding loop U1, the output end of the first adding loop U1 is connected to the input end of the periodic signal generator H1(z), the output end of the periodic signal generator H1(z) is connected to a positive input end of the fifth adding loop U5 after passing through the gain of the first universal expansion coefficient M1, the output end of the periodic signal generator H1(z) is connected to the input end of the periodic signal generator H2(z), the output end of the periodic signal generator H2(z) is connected to the other positive input end of the fifth adding loop U5 after passing through the gain of the second universal expansion coefficient M2, the output end of the fifth adding loop U5 is connected to the other positive input end of the adding loop U1 through the low-pass filter Q(z), and is connected to the other positive input end of the adding loop U1 through the phase advance compensator G f (z) is connected to the output of the frequency adaptive selection harmonic repetitive controller to output c(z).

[0130] In the periodic signal generator H1(z), the input of the periodic signal generator H1(z) is connected to a negative input of a subtraction loop U0 and, after passing through a cosine gain cos(2πm / n), is connected to the positive input of a second addition loop U2. The output of the subtraction loop U0 is connected to the input of a first time delay module τ1. The output of the first time delay module τ1 is connected to the other positive input of a second addition loop U2 after passing through a fractional-order filter F(z). The output of the second addition loop U2 is connected to the input of a second time delay module τ2. The output of the second time delay module τ2 is connected to the output of the periodic signal generator H1(z) after passing through a fractional-order filter F(z).

[0131] In the periodic signal generator H2(z), the input of the periodic signal generator H2(z) is connected to a negative input of a subtraction loop U3 and, after passing through a cosine gain cos(2πm / n), is connected to the positive input of a fourth addition loop U4. The output of the subtraction loop U3 is connected to the input of a first time delay module τ1. The output of the first time delay module τ1 is connected to the other positive input of a fourth addition loop U4 after passing through a fractional-order filter F(z). The output of the fourth addition loop U4 is connected to the input of a second time delay module τ2. The output of the second time delay module τ2 is connected to the output of the periodic signal generator H2(z) after passing through a fractional-order filter F(z).

[0132] Among them, the gain achieved by the repeated control gain module on the input is k rc The first time delay module delays the input z -N / n After the output, the second time delay module delays the input z -N / n After output, the gain achieved by the gain module is cos(2πm / n), where n, m, and k are all integers not less than zero and n≠0 and n>m.

[0133] The transfer function of the frequency adaptive selective harmonic repetitive controller is:

[0134]

[0135] Where H1(z) and H2(z) are:

[0136]

[0137] Where c(z) is the output of the frequency adaptive selection harmonic repetitive controller, e(z) is the error input of the frequency adaptive selection harmonic repetitive controller, H(z) is the digital form of the periodic signal generator, and N = T0 / T s is the period parameter, T sis the sampling period, and z is the z-plane parameter. It should be noted that in actual applications, the frequency adaptive selective harmonic repetitive controller is usually designed and implemented in digital form. The structures of the frequency adaptive selective harmonic repetitive controllers shown in the subsequent examples also have corresponding analog forms. The subsequent embodiments are mainly presented in digital form, and the analog form structure is no longer shown separately.

[0138] like Figure 12 As shown, the frequency-adaptive selective harmonic repetitive controller can be configured with different universal expansion coefficients, thereby achieving different forms of frequency adaptability. Therefore, by changing the value of the universal expansion coefficient, the structure and transfer function of the frequency-adaptive selective harmonic repetitive controller can be switched to suit different usage scenarios, achieving high versatility.

[0139] The two commonly used combinations of general expansion coefficients include the following two cases:

[0140] (1) When M1=1 and M2=0, the frequency adaptive selection harmonic repetitive controller constitutes the repetitive controller of the first extended structure, and its transfer function is:

[0141]

[0142] For different power equipment or electrical drive devices, there are corresponding specific harmonics. For the three-phase grid-connected inverter control system, since its harmonics are mainly concentrated at the (6k±l)th (i.e., 5th, 7th, 11th, 13th, etc.) harmonic frequency components, and its harmonic content gradually decreases with the increase of the harmonic order, it is only necessary to set n=6 and m=1 to achieve error-free tracking and complete elimination of the harmonic signal. For the single-phase grid-connected inverter control system, since its harmonics are mainly concentrated at the (4k±l)th (i.e., 5th, 7th, 11th, 13th, etc.) harmonic frequency components, and its harmonic content gradually decreases with the increase of the harmonic order, it is only necessary to set n=4 and m=1 to achieve error-free tracking and complete elimination of the harmonic signal. When the fundamental frequency fluctuates greatly, by adjusting the fractional-order filter G P The parameters of (s) are used to track and completely eliminate the harmonic signals.

[0143] (2) When M1>1, M2<0, M1+M2=1, the frequency adaptive selection harmonic repetitive controller constitutes the repetitive controller of the second structure, and its transfer function is:

[0144]

[0145] When the fundamental frequency fluctuation is small, the harmonic signal is tracked and eliminated by adjusting the general extended parameters M1 and M2.

[0146] In order to further improve the robustness of the frequency adaptive selection harmonic repetitive controller in practical applications, a low-pass filter Q(z) can also be added to the frequency adaptive selection harmonic repetitive controller. In order to compensate for the phase lag caused by the controlled object and the low-pass filter Q(z) and improve the stability of the controller, a phase advance compensator G can also be added to the frequency adaptive selection harmonic repetitive controller. f (z) Alternatively, the time delay module may be controlled by the time delay damping coefficient K.

[0147] In the frequency-adaptive harmonic repetitive controller parameter selection, real-time controller parameter changes are adopted. The process is as follows: the fundamental frequency is sampled through a phase-locked loop (PLL) to determine whether it is divisible by the sampling frequency, that is, whether the period parameter N is an integer. If not, the extended parameters M1 and M2 are selected based on the frequency fluctuation range. When the frequency fluctuation range is small, the parameter configuration is selected such that M1>1, M2<0, or M1+M2=1. When the frequency fluctuation range is large, the parameter configuration is selected such that M1=1, M2=0. The fractional-order filter parameters are selected based on the sampled fundamental frequency. If necessary, the time delay parameters are adjusted to match the fractional-order filter. Because the stability of the control system is highly sensitive to parameter changes, rapid parameter changes can lead to system instability or oscillation. Therefore, when designing the fractional-order filter, a certain margin should be maintained during parameter calculation and adjustment to ensure system stability despite parameter changes. This margin provides a buffer, preventing performance degradation or instability caused by sudden parameter changes or external interference, thereby enhancing the system's robustness and adaptability.

[0148] Example 9:

[0149] This embodiment will Figure 4 、 Figure 8 The fractional-order universal selective harmonic repetitive controller and the cascaded multi-order universal selective harmonic repetitive controller shown in the figure are operated in parallel to obtain Figure 13 The fractional-order composite high-order parallel frequency adaptive selective harmonic repetitive controller shown.

[0150] The input signal e(z) enters the fractional order control and high order control channels respectively. The first channel is composed of Figure 4 The fractional-order universal selective harmonic repetitive controller shown in the figure is composed of the second channel Figure 8 The high-order general-purpose selected harmonic repetitive controller shown is constructed.

[0151] This fractional-order composite high-order parallel frequency adaptive selective harmonic repetitive controller enhances the multi-channel collaborative processing capability of harmonic suppression and also has high frequency adaptability.

[0152] Example 10:

[0153] This embodiment provides a feedback control system, which adopts the universal selective harmonic repetitive controller described in the above embodiments to achieve tracking and elimination of specified (nk±m) harmonics.

[0154] like Figure 14 As shown, the positive input terminal of the subtraction loop U5 is connected to the input terminal of the feedback control system to obtain the reference input signal i ref (z), the negative input end of the subtraction loop U5 is connected to the output end of the feedback control system to obtain the actual output signal i(z), and the output end of the subtraction loop U5 is connected to the universal selective harmonic repetitive controller G rc The input of (z) provides e(z), and the output of the subtraction loop U5 is also connected to a positive input of the sixth addition loop U6. The universal selection harmonic repetitive controller G rc The output of (z) is connected to the other positive input of the sixth adding loop U6 to provide c(z). The output of the sixth adding loop U6 is connected to the traditional feedback controller G c (z) input, the traditional feedback controller G c The output terminal of (z) is connected to the control object G p The input terminal of (z) provides u(z) as the control object G p (z) input signal, control object G p The output end of (z) is connected to a positive input end of the seventh adding loop U7, the other positive input end of the seventh adding loop U7 is connected to the system disturbance input d(z), and the output end of the seventh adding loop U7 is connected to the output end of the feedback control system to output the actual output signal i(z). rc (z) is a universal selective harmonic repetitive controller in the above-mentioned embodiments of the present application.

[0155] In order to illustrate the practicality and effectiveness of the universal selective harmonic repetitive controller of the present application, a simulation verification based on MATLAB / Simulink was used to build a three-phase grid-connected inverter control system as a feedback control system. In the three-phase grid-connected inverter control system, since its harmonics are mainly concentrated at the (6k±l) frequency components (i.e., odd frequencies such as 5, 7, 11, and 13), and it is necessary to track the fundamental reference signal, it is only necessary to set n=6 and m=1 to achieve error-free tracking of the fundamental reference signal and complete elimination of the specified harmonics. The control goal is to make the output current accurately track the reference voltage, where the reference current is selected as i ref (s) = 3.26*sin(100πt). When the traditional feedback controllers all use the traditional deadbeat controller DB, the repetitive control gain is the same, and the repetitive controller is added at t = 0.1s, the simulation results are compared as follows: Figure 15A 、 Figure 15B 、 Figure 16A 、 Figure 16B 、 Figure 17A and Figure 17B shown.

[0156] When the universal selective harmonic repetitive controller of the present application is added to the feedback control system and n=6 and m=1 are taken to realize the 6k±1 customized harmonic repetitive controller, the steady-state output current FFT analysis waveform and error convergence diagram are shown as follows: Figure 15A and Figure 15B shown.

[0157] To further improve the response speed of the repetitive controller, a second-order general-purpose selective harmonic repetitive controller with L=2-order periodic signal generator cascaded can be used in the above simulation example. The steady-state output current FFT analysis waveform and error convergence diagram are shown as follows: Figure 16A and Figure 16B shown.

[0158] contrast Figure 15A 、 Figure 15B 、 Figure 16A 、 Figure 16B It can be seen that in the above simulation examples, the total harmonic distortion rates THD are 1.07% and 1.04% respectively, both of which can reach very small values. In addition, under the condition of achieving the same harmonic suppression effect, the general-purpose selective harmonic repetitive controller requires 0.3s to reach steady state, while the second-order general-purpose selective harmonic repetitive controller only requires 0.2s to reach steady state. Therefore, the use of a high-order general-purpose selective harmonic repetitive controller can improve the controller response speed without affecting the control performance.

[0159] In another simulation case, the general selective harmonic repetitive controller can also be used as Figure 4 The corresponding embodiment records the combination of the fractional-order filter F(z). When facing grid frequency fluctuations, the period parameter N of the universal selective harmonic repetitive controller will be non-integer, which seriously affects its control performance. According to theory, each delay link requires a fractional-order filter for approximate compensation, so the universal selective harmonic repetitive controller of this application has fewer delay modules. When the grid frequency suddenly changes from 50Hz to 50.5Hz, when using a universal selective harmonic repetitive controller without a built-in fractional-order filter F(z), the steady-state output current FFT analysis waveform and error convergence diagram are as follows respectively. Figure 17A and Figure 17B When the grid frequency suddenly changes from 50Hz to 50.5Hz, using the general selective harmonic repetitive controller without combining the fractional-order filter F(z), the steady-state output current FFT analysis waveform and error convergence diagram are shown as follows. Figure 18A and Figure 18B As shown. Figure 17A 、 Figure 17B and Figure 18A 、 Figure 18B It can be seen that the total harmonic distortion rates of the universal selective harmonic repetitive controller without a built-in fractional-order filter F(z) and the universal selective harmonic repetitive controller with a built-in fractional-order filter F(z) are 1.30% and 0.65% respectively, and the convergence errors are 0.36A and 0.03A respectively. It can be seen that the universal selective harmonic repetitive controller with a built-in fractional-order filter F(z) has better harmonic suppression effect and higher convergence error, and has stronger anti-interference performance against frequency fluctuations.

[0160] When the fundamental frequency fluctuation range is 0.2Hz, configure M1>1, M2<0, M1+M2=1, and do not adjust the fractional-order parameters in real time, the steady-state output current FFT analysis waveform and error convergence change diagram are as follows: Figure 19A and Figure 19B As shown, the current error increases from 0.35 to 0.59A, and the total harmonic distortion THD is 1.35%.

[0161] When the fundamental frequency fluctuation range is 1Hz, at t=0.5s, the grid-side frequency increases from 50Hz to 51Hz at a rate of 2Hz / s. The configuration parameters are selected as M1=1, M2=0, and the fractional-order parameters are adjusted in real time. The steady-state output current FFT analysis waveform and error convergence change diagram are shown as follows: Figure 20A and Figure 20B As shown, the current error is kept at 0.05A and the total harmonic distortion THD is 1.02%.

[0162] contrast Figure 19A 、 Figure 19B and Figure 20A 、 Figure 20B It can be seen that when the parameters are configured as M1>1, M2<0, and M1+M2=1, the steady-state convergence time is significantly improved, but the anti-disturbance performance is poor under frequency fluctuations. When the configuration parameters are selected as M1=1, M2=0, and the fractional-order parameters are adjusted in real time, the current error and harmonics can maintain good performance under frequency fluctuations. Therefore, when using the frequency adaptive selective harmonic repetitive controller of the present application, good performance can be achieved in both states with different parameter selections.

[0163] Some steps in the embodiments of the present invention may be implemented using software, and the corresponding software program may be stored in a readable storage medium, such as a CD or a hard disk.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A universal selective harmonic repetitive controller, characterized in that: include: Repeated control gain module, first adding loop U1 and periodic signal generator; The input end of the repetitive control gain module is connected to the input end of the universal selective harmonic repetitive controller, and the output end is connected to a positive input end of the first adding loop U1; the output end of the first adding loop U1 is connected to the input end of the periodic signal generator; the output end of the periodic signal generator is respectively connected to the other positive input end of the first adding loop U1 and the output end of the universal selective harmonic repetitive controller; The periodic signal generator includes: a subtraction loop U0, a first time delay module τ1, a second addition loop U2, and a second time delay module τ2. The input end of the periodic signal generator is connected to a negative input end of the subtraction loop U0 and is connected to the positive input end of the second addition loop U2 through a gain module; the output end of the subtraction loop U0 is connected to the input end of the first time delay module τ1; the output end of the first time delay module τ1 is connected to the positive input end of the second addition loop U2; the output end of the second addition loop U2 is connected to the input end of the second time delay module τ2 and is connected to the positive input end of the subtraction loop U0 through a gain module, and the output end of the second time delay module τ2 is connected to the output end of the periodic signal generator.

2. The universal selective harmonic repetitive controller according to claim 1, characterized in that: The output end of the first time delay module τ1 is connected to the second adding loop U2 via a first low-pass filter, and the output end of the second time delay module τ2 is connected to the output end of the periodic signal generator via a second low-pass filter.

3. The universal selective harmonic repetitive controller according to claim 2, characterized in that: The first low-pass filter is connected to the second adding loop U2 via a first fractional-order filter, and the second low-pass filter is connected to the output end of the periodic signal generator via a second fractional-order filter.

4. The universal selective harmonic repetitive controller according to any one of claims 1 to 3, characterized in that: The output end of the periodic signal generator is connected to the output end of the universal selective harmonic repetitive controller through a phase advance compensator.

5. A parallel multi-channel universal selective harmonic repetitive controller, characterized in that: It comprises a plurality of universal selective harmonic repetitive controllers as described in any one of claims 1 to 3 and a third adding ring U3 connected in parallel; the input end of each universal selective harmonic repetitive controller is connected to the input end of the parallel multi-channel universal selective harmonic repetitive controller, and the output end is respectively connected to the positive input end of the third adding ring U3; the output end of the third adding ring U3 is connected to the output end of the parallel multi-channel universal selective harmonic repetitive controller.

6. The parallel multi-channel universal selective harmonic repetitive controller according to claim 5, characterized in that: The output end of the third adding loop U3 is connected to the output end of the universal selective harmonic repetitive controller through a phase lead compensator.

7. A cascaded multi-order selection universal harmonic repetitive controller, characterized in that: It includes a repetitive control gain module, a first adding loop U1, an L-stage cascaded periodic signal generator and a fourth adding loop U4; the periodic signal generator is the periodic signal generator described in claims 1-3; The input end of the repetitive control gain module is connected to the input end of the universal selective harmonic repetitive controller, and the output end is connected to a positive input end of the first adding loop U1; The input end of the first-order periodic signal generator H1(z) is connected to the output end of the first adding loop U1. Starting from the second-order periodic signal generator, any l-th-order periodic signal generator H l The input of (z) is connected to the l-1 order periodic signal generator H l-1 (z) output terminal, any l-th order signal generator H l The output of (z) is extended by a universal expansion factor M l It is connected to a positive input end of the first adding ring U1 , and the output end of the first adding ring U1 is respectively connected to the positive input end of the adding ring U0 and the output end of the cascaded multi-order selective harmonic repetitive controller.

8. The cascaded multi-order selection universal harmonic repetitive controller according to claim 7, characterized in that: The output ends of the time delay modules in the periodic signal generator are connected to the next link through a fractional order filter.

9. A fractional-order composite high-order parallel universal selective harmonic repetitive controller, characterized in that: It includes the universal selective harmonic repetitive controller as described in claim 3 and the cascaded multi-order selective harmonic repetitive controller as described in claim 7, and the universal selective harmonic repetitive controller and the cascaded multi-order selective harmonic repetitive controller are combined in parallel to form any composite controller.

10. A feedback control system, characterized in that: The general selective harmonic repetitive controller G comprising a subtraction loop U5 and any one of claims 1 to 9 rc (z), sixth addition ring U6, seventh addition ring U7; The positive input terminal of the subtraction loop U5 is connected to the input terminal of the feedback control system to obtain the reference input signal i ref (z), the negative input end is connected to the output end of the feedback control system to obtain the actual output signal i(z), and the output end is respectively connected to the universal selective harmonic repetitive controller G rc (z) input end and a positive input end of the sixth adding loop U6; the universal selective harmonic repetitive controller G rc The output end of (z) is connected to the other positive input end of the sixth adding ring U6; the output end of the sixth adding ring U6 is connected to the traditional feedback controller G c (z) input terminal; the traditional feedback controller G c The output terminal of (z) is connected to the control object G p (z) input terminal; the control object G p The output end of (z) is connected to a positive input end of the seventh adding loop U7; the other positive input end of the seventh adding loop U7 is connected to the system disturbance input d(z), and the output end is connected to the output end of the feedback control system.

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