A universal multi-channel repetition controller

Abstract

The application discloses a general multi-channel repetitive controller, and relates to the field of repetitive controllers. Three channels of the general multi-channel repetitive controller can be configured with different general extension coefficients respectively. Different value combinations of the three general extension coefficients can make the general multi-channel repetitive controller form repetitive controllers with different structures and different transfer functions. Different n and m parameters are configured to suppress the sub-harmonic waves in different application scenarios. Therefore, the general multi-channel repetitive controller has a faster control speed under the condition that the gain realized by the repetitive control gain module is the same. The general multi-channel repetitive controller has high universality, a wide application range and high flexibility, and can meet the use requirements of different application occasions.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of repetitive controllers, and particularly to a universal multi-channel repetitive controller. BACKGROUND

[0002] In order to promote the process of achieving the goal of "carbon neutralization and carbon peak", it is particularly important to establish a new power system mainly based on new energy. When the new energy station based on wind energy, solar energy, water energy, biomass energy and other new energies is connected to the grid, the stability of the power system will be affected, including system frequency fluctuation, voltage asymmetry and the like, which will affect the voltage and current waveform of the power system and seriously affect the performance of the related controller.

[0003] The control performance of periodic signals determines the control performance of the power system to some extent. For various power equipment, it is particularly important to adopt a targeted control strategy to improve the control level of periodic signals. Different power equipment is disturbed by different harmonic interference. For example, the main harmonic pollution of a three-phase grid-connected converter during operation is concentrated in (6k±1)(k=1,2,…), and the main harmonic pollution of a single-phase grid-connected converter during operation is concentrated in (4k±1)(k=1,2,…). With the increase of the harmonic number, the component is less and less, and the above two kinds of harmonic occupy the main position in industrial occasions.

[0004] The repetitive controller based on the internal model principle can realize the steady-state error tracking and disturbance elimination for periodic signals. At present, there are many researches. Subsequent scholars include Wenzhou Lu et al. in “A novel repetitive controller for nk±m order harmonics compensation,” Proceedings of the 30th Chinese Control Conference, 2011, proposed a specified nk±m order harmonic repetitive controller, and in “A Generic Digital nk±m-Order Harmonic Repetitive Control Scheme for PWM Converters”, IEEE Transactions on Industrial Electronics, 2013, proposed an improved (nk±m) order harmonic repetitive controller, and in “A kind of custom harmonic repetitive controller and control method”, 2020, proposed a (nk±m) order harmonic repetitive controller, which can all realize the error elimination for specified nk±m order harmonics. However, the current various repetitive controllers are generally customized repetitive controllers designed for specific occasions. Different repetitive controllers need to be designed for different application scenarios, and the functions are relatively single and the application range is narrow. SUMMARY

[0005] The applicant proposes a general multi-channel repetitive controller for the above problems and technical needs. The technical scheme of the present application is as follows:

[0006] A general multi-channel repetitive controller, the general multi-channel repetitive controller comprises a repetitive control gain module and a periodic signal generator H(s), the input end of the repetitive control gain module is connected with the input end of the general multi-channel repetitive controller to obtain e(s), the output end of the repetitive control gain module is connected with the input end of the periodic signal generator H(s), and the output end of the periodic signal generator H(s) is connected with the output end of the general multi-channel repetitive controller to output c(s).

[0007] In the periodic signal generator H(s): one positive input terminal of the addition ring U1 is connected with the input terminal of the periodic signal generator H(s), the output terminal of the addition ring U1 is connected with the input terminal of the time delay module τ1, the negative input terminal of the subtraction ring U2, the input terminal of the time delay module τ3, the input terminal of the time delay module τ4 and one positive input terminal of the addition ring U4; the output terminal of the time delay module τ1 is connected with one positive input terminal of the addition ring U3, the output terminal of the addition ring U3 is connected with the positive input terminal of the subtraction ring U2 through the time delay module τ2, the output terminal of the subtraction ring U2 is connected with another positive input terminal of the addition ring U3 through the positive feedforward gain module K1, and the output terminal of the subtraction ring U2 is also connected with the first positive input terminal of the addition ring U6 through the general expansion coefficient C3;

[0008] The output terminal of the time delay module τ3 is connected with the second positive input terminal of the addition ring U6 through the general expansion coefficient C2; the output terminal of the time delay module τ4 is connected with the negative input terminal of the subtraction ring U5, the output terminal of the subtraction ring U5 is connected with the input terminal of the time delay module τ5, and the output terminal of the time delay module τ5 is connected with another positive input terminal of the addition ring U1, another positive input terminal of the addition ring U4 respectively, and the output terminal of the addition ring U4 is connected with the positive input terminal of the subtraction ring U5 through the positive feedforward gain module K2; the output terminal of the time delay module τ5 is also connected with the third positive input terminal of the addition ring U6 through the general expansion coefficient C1; the output terminal of the addition ring U6 is connected with the output terminal of the periodic signal generator H(s).

[0009] The gain realized by the repetitive control gain module is k rc The delay realized by all the time delay modules to the input quantity is T The gain realized by all the positive feedforward gain modules is cos(2πm / n).

[0010] The general multi-channel repetitive controller forms repetitive controllers with different structures and different transfer functions under different combinations of the values of the three general expansion coefficients; when forming each kind of structure of the repetitive controller, the general multi-channel repetitive controller is used to realize the tracking and elimination of (nk±m)th harmonic, T0 is the fundamental period, n, m and k are all integers not less than zero and n≠0, n>m.

[0011] The beneficial technical effects of the present application are:

[0012] The general multi-channel repetitive controller can be configured with different general expansion coefficients for each of the three channels, and by configuring different combinations of the values of the three general expansion coefficients, the general multi-channel repetitive controller can form repetitive controllers with different structures and different transfer functions. By configuring different n and m parameters, the general multi-channel repetitive controller can realize the suppression of (nk±m)th harmonic under different application scenarios, so that the general multi-channel repetitive controller can be applied to different application scenarios.rc In the same case, it can have a faster control speed. The universal multi-channel repetitive controller has high universality, wide application range and high flexibility, and can adapt to the use needs of different application occasions.

[0013] The universal multi-channel repetitive controller can realize accurate and rapid control of specified order harmonics, and has simple and beautiful structure, convenient design, and less memory storage units.

[0014] The universal multi-channel repetitive controller can further extend to form an L-order periodic signal generator cascade structure to further optimize the control performance, and can also show good harmonic suppression ability and rapid performance when the fundamental frequency changes.

[0015] The universal multi-channel repetitive controller can further extend to form a multi-control channel parallel structure, and can realize elimination of all or specified order harmonics, and can independently adjust the control gain of each order harmonic to further optimize the control performance.

[0016] The universal multi-channel repetitive controller can further embed a low-pass filter to improve robustness, and can further embed a phase lead compensator or make a time delay module controlled by a 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 multi-channel repetitive controller.

[0017] The universal multi-channel repetitive controller can further embed a fractional order filter. The traditional repetitive controller will make the periodic parameter N in the repetitive controller be a non-integer when facing the fundamental frequency fluctuation, which seriously affects the control performance of the repetitive controller. Therefore, the universal multi-channel repetitive controller can improve the harmonic suppression ability of the repetitive controller after embedding the fractional order filter. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the control structure diagram of the universal multi-channel repetitive controller in an embodiment of the present application.

[0019] Figure 2 is Figure 1 the control structure diagram corresponding to the digital form.

[0020] Figure 3 is Figure 1 the control structure diagram when C1=0, C2=1, and C3=0.

[0021] Figure 4 isFigure 1 Control structure diagram when C1=0, C2=0, C3=1 is configured.

[0022] Figure 5 is an equivalent control structure diagram of Figure 4 .

[0023] Figure 6 is a control structure diagram when a low-pass filter and a phase lead compensator are added in Figure 1 .

[0024] Figure 7 is an equivalent control structure diagram of Figure 6 when C1=0, C2=1, C3=0 is configured.

[0025] Figure 8 is a control structure diagram when a low-pass filter and a time delay damping coefficient are added in Figure 1 .

[0026] Figure 9 is an equivalent control structure diagram of Figure 8 when C1=0, C2=0, C3=1 is configured.

[0027] Figure 10 is a control structure diagram when a fractional order filter is further added in Figure 6 .

[0028] Figure 11 is a parallel structure based on the structure of Figure 1 extended to multiple parallel branches, and a control structure diagram when a low-pass filter and a phase lead compensator are added.

[0029] Figure 12 is another parallel structure based on the structure of Figure 1 extended to multiple parallel branches, and a control structure diagram when a low-pass filter and a time delay damping coefficient are added.

[0030] Figure 13 is a control structure diagram of a general multi-channel repetitive controller based on the structure of Figure 1 extended to high order.

[0031] Figure 14 is a control structure diagram when a low-pass filter and a phase lead compensator are added in Figure 13 .

[0032] Figure 15 is a system structure diagram of a feedback control system in which the general multi-channel repetitive controller is built in an embodiment of the present application.

[0033] Figure 16Fig. 1 is a simulation result diagram when a conventional CRC controller is used in a simulation example, (a) is a steady-state output current FFT analysis waveform, and (b) is an error convergence change diagram.

[0034] Figure 17 Fig. 2 is a simulation result diagram when a universal multi-channel repetitive controller of the present application is used in a simulation example, (a) is a steady-state output current FFT analysis waveform, and (b) is an error convergence change diagram. DETAILED DESCRIPTION

[0035] The specific embodiments of the present application will be further described below with reference to the accompanying drawings.

[0036] The present application discloses a universal multi-channel repetitive controller, please refer to Figure 1 The universal multi-channel repetitive controller comprises a repetitive control gain module 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 multi-channel repetitive controller to obtain e(s), the output end of the repetitive control gain module is connected to the input end of the periodic signal generator H(s), and the output end of the periodic signal generator H(s) is connected to the output end of the universal multi-channel repetitive controller to output c(s). In the periodic signal generator H(s):

[0037] The input end of the periodic signal generator H(s) is connected to a positive input end of an addition ring U1, the output end of the addition ring U1 is connected to the input end of a time delay module τ1, the negative input end of a subtraction ring U2, the input end of a time delay module τ3, the input end of a time delay module τ4, and a positive input end of an addition ring U4. The output end of the time delay module τ1 is connected to a positive input end of an addition ring U3, the output end of the addition ring U3 is connected to the positive input end of the subtraction ring U2 through a time delay module τ2, the output end of the subtraction ring U2 is connected to another positive input end of the addition ring U3 through a positive feedforward gain module K1, and the output end of the subtraction ring U2 is also connected to a first positive input end of an addition ring U6 through a universal expansion coefficient C3.

[0038] The output end of the time delay module τ3 is connected to a second positive input end of the addition ring U6 through a universal expansion coefficient C2. The output end of the time delay module τ4 is connected to the negative input end of a subtraction ring U5, the output end of the subtraction ring U5 is connected to the input end of a time delay module τ5, the output end of the time delay module τ5 is respectively connected to another positive input end of the addition ring U1 and another positive input end of the addition ring U4, and the output end of the addition ring U4 is connected to the positive input end of the subtraction ring U5 through a positive feedforward gain module K2. The output end of the time delay module τ5 is also connected to a third positive input end of the addition ring U6 through a universal expansion coefficient C1, and the output end of the addition ring U6 is connected to the output end of the periodic signal generator H(s).

[0039] The gain realized by the repetitive control gain module is k rc The delay realized by all the time delay modules on the input quantity is The gain realized by all the positive feedforward gain modules is cos(2πm / n).

[0040] The transfer function of the universal multi-channel repetitive controller is:

[0041]

[0042] wherein T0 is the fundamental 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, n>m.

[0043] In actual application, the universal multi-channel repetitive controller is usually designed and realized in digital form, Figure 1 The digital form of the universal multi-channel repetitive controller of formula (1) is shown in Figure 2 and its transfer function is:

[0044]

[0045] wherein c(z) is the output quantity of the universal multi-channel repetitive controller, e(z) is the error input quantity of the universal multi-channel 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. It should be noted that the structures of the universal multi-channel repetitive controllers shown in the subsequent examples also each have a corresponding digital form, and the digital form structures are not shown in the subsequent embodiments.

[0046] As shown in Figure 1 , the three channels of the universal multi-channel repetitive controller can each be configured with different universal extension coefficients. By configuring different value combinations of the three universal extension coefficients, the universal multi-channel repetitive controller can be formed into repetitive controllers with different structures and different transfer functions. Therefore, by switching the value combinations of the universal extension coefficients, the structure and the transfer function of the universal multi-channel repetitive controller can be switched to adapt to the use needs of different occasions, and the universality is high. When formed into each kind of structure of repetitive controller, the universal multi-channel repetitive controller is used to realize the tracking and elimination of (nk±m)th harmonic, wherein n, m, k are integers not less than zero and n≠0, n>m.

[0047] In this application, the value combinations of the three universal extension coefficients include the following cases:

[0048] (1) When C1 = 0, C2 = 1, and C3 = 0, the general-purpose multi-channel repetitive controller is formed as the first structure repetitive controller, and its equivalent structure is as follows: Figure 3 As shown, the transfer function of this general-purpose multi-channel repetitive controller is:

[0049]

[0050] according to Figure 3 It can be seen that the repetitive controller of the first structure contains three time delay modules, and therefore occupies 3N / n memory units. Therefore, when n>3, the storage space occupied by this general-purpose multi-channel repetitive controller is much smaller than that of a conventional repetitive controller, and it has a significant advantage in speed.

[0051] The three time delay modules of this repetitive controller implement the same delay element, and the delay time is 1 / n of the fundamental period T0. Furthermore, the total delay time is much shorter than that of a traditional repetitive controller. Therefore, the gain of the repetitive control gain module is k. rc Under the same conditions, it is possible to achieve faster control of specified (nk±m) harmonics.

[0052] Figure 3 The transfer function of the general-purpose multichannel repetitive controller with the structure shown can be rewritten as:

[0053]

[0054] In the above formula, m≠0. When m=0, it can be further simplified to:

[0055]

[0056] Therefore, the pole of the general-purpose multi-channel repetitive controller of the first structure falls at the frequency (nk±m)ω0, and the gain of the general-purpose multi-channel repetitive controller is infinite at the frequency (nk±m)ω0. Therefore, by selecting appropriate values ​​of n and m, the general-purpose multi-channel repetitive controller can be used to track and eliminate the (nk±m)th harmonic.

[0057] For different power equipment or electrical drive devices, there are corresponding specific harmonics. For a three-phase grid-connected inverter control system, since its harmonics are mainly concentrated at (6k±l)th (i.e. 5, 7, 11, 13, etc.) harmonic frequency components, and with the increase of the harmonic number, the harmonic content gradually decreases, so only n = 6 and m = 1 can be used to realize error-free tracking and complete elimination of the harmonic signal. For a single-phase grid-connected inverter control system, since its harmonics are mainly concentrated at (4k±l)th (i.e. 5, 7, 11, 13, etc.) harmonic frequency components, and with the increase of the harmonic number, the harmonic content gradually decreases, so only n = 4 and m = 1 can be used to realize error-free tracking and complete elimination of the harmonic signal.

[0058] (2) When C1 = 0, C2 = 0, C3 = 1, the general multi-channel repetitive controller forms a repetitive controller of the second structure, whose equivalent structure is shown in Figure 4 , and the transfer function of the general multi-channel repetitive controller is:

[0059]

[0060] After equivalent transformation, Figure 4 , the structure shown in Figure 5 can be further equivalent, and the transfer functions of the two are consistent. According to Figure 5 , the repetitive controller of the second structure contains two time delay modules, and the delay time is 1 / n of the fundamental period T0, and the total delay time is much shorter than that of the traditional repetitive controller, so when the gain of the repetitive control gain module is k rc , the specified (nk±m)th harmonic can be controlled more quickly under the same condition. By selecting different k rc , different error convergence speeds can be obtained, but the stability of the repetitive controller will be affected to some extent, so a suitable repetitive controller gain k rc needs to be selected in a good trade-off between stability and speed.

[0061] Therefore, the repetitive controller of the second structure occupies 2N / n memory units. Therefore, when n > 2, the storage space occupied by the general multi-channel repetitive controller is much smaller than that of the conventional repetitive controller, and there is a clear advantage in speed. The control analysis of the (nk±m)th harmonic of the repetitive controller of the second structure is similar to the above case (1), and will not be described again.

[0062] (3) When C1 = 1, C2 = 0, C3 = 0, the general multi-channel repetitive controller forms a repetitive controller of the third structure, which is similar to the above two cases and will not be shown separately. At this time, the transfer function of the general multi-channel repetitive controller is And the third structure of the repetitive controller contains two time delay modules, thus occupying 2N / n memory units and being able to achieve more rapid control for the specified (nk±m) harmonic as well.

[0063] In Figure 1 Based on the structure shown in the figure, in order to further improve the robustness of the general multi-channel repetitive controller in practical application, a low-pass filter Q(s) can be added to the general multi-channel repetitive controller. In order to compensate for the phase lag caused by the control object and the low-pass filter Q(s) and improve the stability of the controller, a phase-advance compensator G f (s) or make the time delay module controlled by a time delay damping coefficient K. In practical application, the robustness of the general multi-channel repetitive controller can be optimized, or only the stability can be optimized, but more commonly, since both robustness and stability are important parameter indicators, the present application takes the example of optimizing both the robustness and the stability of the general multi-channel repetitive controller.

[0064] In one embodiment, as Figure 6 shown, in the periodic signal generator H(s), the input end of the time delay module τ1, the output end of the positive feedforward gain module K1, the output end of the time delay module τ3, the output end of the time delay module τ4, and the output end of the time delay module τ5 are respectively connected with a low-pass filter Q(s). And the output end of the periodic signal generator H(s) is connected with the output end of the general multi-channel repetitive controller through a phase-advance compensator G f (s).

[0065] Based on Figure 6 the structure shown in the figure, when the configuration C1=0, C2=1, C3=0, the structure diagram of the general multi-channel repetitive controller is as Figure 7 shown in the figure, at this time the transfer function of the general multi-channel repetitive controller becomes The structure diagram and the transfer function when taking other value combinations of the general expansion coefficient can be similarly deduced, and this embodiment will not be shown separately.

[0066] In another embodiment, as Figure 8 shown, in the periodic signal generator H(s), the input end of the time delay module τ1, the output end of the positive feedforward gain module K1, the output end of the time delay module τ3, the output end of the time delay module τ4, and the output end of the time delay module τ5 are respectively connected with a low-pass filter Q(s). And the delay achieved by all the time delay modules in the periodic signal generator H(s) is also controlled by a time delay damping coefficient K, thus being

[0067] Based on Figure 8The structure shown, when the configuration C1=0, C2=0, C3=1, combined with Figure 5 The equivalent structure shown, the structure diagram of the general multi-channel repetitive controller is as Figure 9 The equivalent structure shown, the structure diagram of the general multi-channel repetitive controller is as The structure diagram and transfer function of other value combinations of general extended coefficients can be similarly analogized, and this embodiment will not be shown separately.

[0068] In Figure 6 And Figure 8 The general multi-channel repetitive control further includes a fractional order filter G p (s) to further optimize the robustness, then as Figure 10 To further improve on the basis of Figure 6 The fractional order filter G p (s) is connected between the time delay module τ1 and the low-pass filter Q(s) at its input end, between the positive feedforward gain module K1 and the low-pass filter Q(s) at its output end, between the time delay module τ3 and the low-pass filter Q(s) at its output end, between the time delay module τ4 and the low-pass filter Q(s) at its output end, and between the time delay module τ5 and the low-pass filter Q(s) at its output end. When the configuration C1=0, C2=0, C3=1, the transfer function of the general multi-channel repetitive control is By adding the fractional order filter G p (s), the general multi-channel repetitive control can effectively solve the problem of mismatch between the internal mode of the repetitive controller and the specified periodic signal at the resonance point of the response frequency when the base frequency changes, and the fractional order filter 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.

[0069] In another embodiment, the general multi-channel repetitive control can also be further extended to form a multi-parallel branch structure based on the structure of a single branch shown. Figures 1-10 As shown in Figure 11 And Figure 12 The general multi-channel repetitive controller includes p+1 parallel branches, each parallel branch includes a repetitive control gain module and a periodic signal generator H(s) connected in series. The input end of the repetitive control gain module in each parallel branch is connected to the input end of the general multi-channel repetitive controller to obtain e(s), and the output end of the periodic signal generator H(s) in each parallel branch is connected to a positive input end of the summing ring U7, and the output end of the summing ring U7 is connected to the output end of the general multi-channel repetitive controller.

[0070] There are two ways to form the parallel structure by multiple parallel branches:

[0071] Way one, please refer to Figure 11 , the delay realized by the time delay module in all parallel branches is equal to The gain realized by the repetitive control gain module in different parallel branches is different, in order to distinguish, the gain realized by the repetitive control gain module in any ith parallel branch is The gain realized by the positive feedforward gain module in different parallel branches is different, in order to distinguish, the gain realized by the positive feedforward gain module in any ith parallel branch is cos(2πi / n), i is a parameter and i∈[0,p].

[0072] In this way, p=m. Wherein, n and m are positive integers, and when n is even, m∈[0,n / 2]; when n is odd, m∈[0,[n / 2]], [n / 2] represents taking n / 2 to integer, the general multi-channel repetitive controller is used to realize the elimination of all harmonics, and the general multi-channel repetitive controller is used to realize the elimination of all harmonics.

[0073] Based on the parallel structure of the first way, when C1=0, C2=1, C3=0, the transfer function of the general multi-channel repetitive controller is When C1=0, C2=0, C3=1, the transfer function of the general multi-channel repetitive controller is

[0074]

[0075] Way two, please refer to Figure 12 The gain realized by the repetitive control gain module in different parallel branches is different, in order to distinguish, the gain realized by the repetitive control gain module in any ith parallel branch is k r i c . The gain realized by the positive feedforward gain module in different parallel branches is different, in order to distinguish, the gain realized by the positive feedforward gain module in any ith parallel branch is cos(2π·m i / n i ). The delay realized by the time delay module in different parallel branches is different, in order to distinguish, the delay realized by the time delay module in any ith parallel branch is In this way, n i and m i are any positive integers, the general multi-channel repetitive controller is used to realize the elimination of specified harmonics and has independent adjustment function for the gain of each harmonic.

[0076] Based on the parallel structure of the second mode, when the configuration C1=0, C2=1, C3=0, the transfer function of the general multi-channel repetitive controller is When the configuration C1=0, C2=0, C3=1, the transfer function of the general multi-channel repetitive controller is

[0077]

[0078] No matter which multi-parallel branch parallel structure is adopted, in the case of parallel branch parallel, the robustness and stability can also be improved according to the above method. Then, similar to the single branch structure, one case is that it can be improved by adding a low-pass filter and a phase lead compensator, such as Figure 11 Taking this case as an example, the periodic signal generator H i (s) of any i-th parallel branch, the input end of the time delay module τ1, the output end of the positive feedforward gain module K1, the output end of the time delay module τ3, the output end of the time delay module τ4, and the output end of the time delay module τ5 are respectively connected with a low-pass filter Q i (s), and the output end of the addition ring U7 is connected with the output end of the general multi-channel repetitive controller through a phase lead compensator G f (s). Then, when the parallel structure of the first mode is adopted and the low-pass filter and the phase lead compensator are added, and the configuration C1=0, C2=1, C3=0, the transfer function of the general multi-channel repetitive controller is When the parallel structure of the second mode is adopted and the low-pass filter and the phase lead compensator are added, and the configuration C1=0, C2=1, C3=0, the transfer function of the general multi-channel repetitive controller is

[0079]

[0080] Another case is that it can be improved by adding a low-pass filter and a time delay damping coefficient, such as Figure 12 Taking this case as an example, then the periodic signal generator H i (s) of any i-th parallel branch, the input end of the time delay module τ1, the output end of the positive feedforward gain module K1, the output end of the time delay module τ3, the output end of the time delay module τ4, and the output end of the time delay module τ5 are respectively connected with a low-pass filter Q i (s); and the delay achieved by all time delay modules in all parallel branches is also controlled by a time delay damping coefficient K. Then, when the parallel structure of the first mode is adopted and the low-pass filter and the time delay damping coefficient K are added, and the configuration C1=0, C2=0, C3=1, the transfer function of the general multi-channel repetitive controller is Then, following the parallel structure of Method 2, and adding a low-pass filter and a time delay damping coefficient K, with C1=0, C2=0, and C3=1, the transfer function of this general-purpose multi-channel repetitive controller is:

[0081]

[0082] Furthermore, regardless of Figure 11 still Figure 12 Based on this, a fractional-order filter G can also be added. p (s) Further improve robustness, no longer illustrated separately.

[0083] Besides being able to Figure 1 In addition to expanding upon the existing structure to form a multi-parallel branch parallel structure, it can also be used to... Figure 1 Based on this, a higher-order repetitive controller structure is formed. An L-order periodic signal generator is connected in series between the output of this repetitive control gain module and the output of the general-purpose multi-channel repetitive controller. Further details will follow... Figure 1 This article will use the example of extending a higher-order repetitive controller structure based on the above. However, it should be noted that when using a structure with multiple parallel branches, each parallel branch can also be extended to form a higher-order repetitive controller according to the following methods.

[0084] like Figure 13 As shown, the output of the repetitive control gain module is connected to one positive input of the adder loop U8, and the output of the adder loop U8 is connected to the first-order periodic signal generator H. 1 The input terminal of (s) starts from the second-order periodic signal generator, and any l-order periodic signal generator H l The input terminal of (s) is connected to the (l-1)th order periodic signal generator H. l-1 The output of (s) is a parameter where l ∈ [1, L]. Any l-th order periodic signal generator H l The output of (s) is connected to a constant coefficient M. l Connect one positive input terminal of the adder loop U9. Connect the output terminal of the adder loop U9 to the other positive input terminal of the adder loop U8 and the output terminal of the general-purpose multi-channel repeater controller.

[0085] The higher the order L of the cascaded periodic signal generators, the faster the control response of this general-purpose multi-channel repetitive controller, resulting in better control performance. However, this also increases design complexity. To balance these two aspects, L is typically set to 2. The transfer function of this general-purpose multi-channel repetitive controller can be written as:

[0086] In the expansion formation as Figure 13Based on the high-order repetitive controller structure shown, robustness and stability can be further improved using the methods described above. However, a unique feature of the high-order repetitive controller structure is that the L-order periodic signal generator can share the low-pass filter Q(s), as follows: Figure 14 As shown, the output of the adder loop U9 is connected to a low-pass filter Q(s) and a phase lead compensator G. f Connect the output of the general-purpose multi-channel repetitive controller (s) to the output of the low-pass filter Q(s), and connect the output of the low-pass filter Q(s) to the other positive input of the adder loop U8, so that the output of the adder loop U9 is connected to the adder loop U8 through the low-pass filter Q(s). Then the transfer function of this general-purpose multi-channel repetitive controller can be written as: Or you can also Figure 14 Phase lead compensator G in f (s) Removed to ensure that the delay implemented by the time delay module in each periodic signal generator is still controlled by the time delay damping coefficient K. Similarly, both cases can further increase the fractional-order filter G. p (s). Similar to the above, no further illustrations will be shown.

[0087] The general-purpose multi-channel repetitive controller provided in the above embodiments can be applied to various feedback control systems to achieve tracking and elimination of specified (nk±m) harmonics. Please refer to... Figure 15 The positive input terminal of the subtraction loop U10 is connected to the input terminal of the feedback control system to obtain the reference input signal i. ref (s), the negative input terminal of the subtraction loop U10 is connected to the output terminal of the feedback control system to obtain the actual output signal i(s), and the output terminal of the subtraction loop U10 is connected to the general-purpose multi-channel repetitive controller G. rc The input terminal of (s) provides e(s), and the output terminal of the subtraction loop U10 is also connected to a positive input terminal of the addition loop U11. The general-purpose multi-channel repetitive controller G... rc The output of c(s) is connected to the other positive input of the adder loop U11 to provide c(s). The output of the adder loop U11 is connected to the conventional feedback controller G. c The input terminal of (s), traditional feedback controller G c The output of (s) is connected to the control object G. o The input terminal of (s) provides u(s) as the control object G. o The input signal of (s), the controlled object G o The output terminal of (s) is connected to one positive input terminal of the adder loop U12, and the other positive input terminal of the adder loop U12 is connected to the system disturbance input d(s). The output terminal of the adder loop U12 is connected to the output terminal of the feedback control system to output the actual output signal i(s). General-purpose multi-channel repetitive controller G rc(s) is a general multi-channel repetitive controller in each embodiment of the present application.

[0088] In order to illustrate the practicability and effectiveness of the general multi-channel repetitive controller of the present application, a simulation verification based on MATLAB / Simulink is adopted, and a three-phase grid-connected inverter control system is built as a feedback control system. In the three-phase grid-connected inverter control system, the harmonics are mainly concentrated at (6k±1) frequencies, so only m=1 and n=6 are needed, and theoretically, error-free tracking of periodic signals and elimination of specified harmonic frequencies can be achieved. The control target is to make the output current accurately track the reference voltage, where the reference current i ref =6.53*sin(100πt), in the traditional feedback controller G c (s) are all the traditional deadbeat controller DB, the repetitive control gain k rc is the same, and different repetitive controllers are added at t=0.1s, the comparison simulation results are shown in Figure 16 and Figure 17

[0089] When the traditional repetitive controller, i.e., the CRC controller, is added to the feedback control system, the steady-state output current FFT analysis waveform and the error convergence change diagram are shown in Figure 16 (a) and (b), respectively.

[0090] The general multi-channel repetitive controller of the present application Figure 1 is added to the feedback control system, C1=0, C2=0, C3=1, m=1 and n=6 are taken, and the steady-state output current FFT analysis waveform and the error convergence change diagram are shown in Figure 17 (a) and (b), respectively.

[0091] As can be seen from the comparison of Figure 16 and Figure 17 , when the CRC controller is adopted, the total harmonic distortion (THD) is 0.13%, and when the general multi-channel repetitive controller of the present application is adopted, the total harmonic distortion is 0.28%, both of which can achieve very small values. However, the CRC controller needs about 0.08s to reach steady state, while the general multi-channel repetitive controller of the present application only needs 0.02s to reach steady state, and the error convergence speed is about 4 times that of the traditional CRC controller, which has a significant advantage in error convergence speed.

[0092] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.​

Claims

1. A universal multi-channel repetition controller, characterized by, The universal multi-channel repetitive controller comprises a repetitive control gain module and a periodic signal generator The input end of the repetitive control gain module is connected to the input end of the universal multi-channel repetitive controller The output end of the repetitive control gain module is connected to the input end of the periodic signal generator The output end of the periodic signal generator is connected to the output end of the universal multi-channel repetitive controller ​ In the periodic signal generator In the middle: the periodic signal generator The input terminal is connected to the addition loop. One positive input terminal, addition ring The output terminal is connected to a time delay module. Input terminal, subtraction loop Negative input terminal, time delay module Input terminal, time delay module Input terminals and addition ring A positive input terminal; time delay module The output terminal is connected to the addition loop. One positive input terminal, addition ring The output terminal is connected to a time delay module. Connect the subtraction ring The positive input terminal, the subtraction loop The output terminal is connected to a positive feedforward gain module. Connect the addition ring The other positive input, the subtraction loop The output terminal also uses a universal expansion factor. Connect the addition ring The first positive input terminal; the output of the time delay module is connected through a common scaling factor to a positive input of the summing loop ; the second positive input of the summing loop is connected to the output of the time delay module ; the negative input of the summing loop is connected to the output of the time delay module ; the input of the time delay module is connected to the output of the summing loop ; the other positive input of the summing loop is connected to the output of the summing loop ; the output of the summing loop is connected to a positive input of the difference loop ; the output of the time delay module is also connected through a common scaling factor to a positive input of the summing loop ; the third positive input of the summing loop is connected to the output of the periodic signal generator ; the output of the periodic signal generator The gain realized by the repetitive control gain module is The delay realized by all the time delay modules on the input quantity is The gain realized by all the positive feedforward gain modules is ; The universal multi-channel repetitive controller is formed into repetitive controllers of different structures and has different transfer functions under different combinations of values of three universal extension coefficients, and the transfer function of the universal multi-channel repetitive controller is ; when formed into repetitive controllers of each structure, the universal multi-channel repetitive controller is used to realize tracking and elimination of sub-harmonics, for a fundamental period, , , are all integers not less than zero and , .

2. The universal multi-channel repetition controller of claim 1, wherein, The value combination of the three general extension coefficients includes: When the general multi-channel repetitive controller is formed as a repetitive controller of a first structure, occupies one memory unit and the transfer function is ; When the general multi-channel repetitive controller is formed as a repetitive controller of a second structure, occupies one memory unit and the transfer function is ; When the general multi-channel repetitive controller is formed as a repetitive controller of a third structure, occupies one memory unit and the transfer function is ; wherein is a periodic parameter, is a sampling period.

3. The universal multi-channel repetition controller according to claim 1, characterized in that, In the periodic signal generator , the input end of the time delay module , the output end of the positive feedforward gain module , the output end of the time delay module , the output end of the time delay module , the output end of the time delay module are respectively connected with low-pass filters ; and the output end of the periodic signal generator is connected with the output end of the general multi-channel repetition controller through a phase lead compensator . Or; in the periodic signal generator The input end of the time delay module The output end of the positive feedforward gain module The output end of the time delay module The output end of the time delay module The output end of the time delay module The output end of the time delay module Are respectively connected with low-pass filters And the delay realized by all the time delay modules in the periodic signal generator Is also controlled by a time delay damping coefficient 4. The universal multi-channel repetition controller of claim 3, wherein, time delay module and a low pass filter at its input and a positive feed forward gain module and a low pass filter at its output and a time delay module and a low pass filter at its output and a time delay module and a low pass filter at its output and a time delay module and a low pass filter at its output fractional order filters​ 5. The universal multi-channel repetition controller of claim 1, wherein, The general-purpose multi-channel repetitive controller includes Each of the parallel branches includes the repetitive control gain module and the periodic signal generator connected in series. The input terminals of the repetitive control gain modules in each parallel branch are all connected to the input terminals of the general-purpose multi-channel repetitive controller to obtain the data. Periodic signal generators in each parallel branch The output terminals are connected to the addition loop respectively. One positive input terminal, addition ring The output terminal is connected to the output terminal of the general-purpose multi-channel repeater controller.

6. The universal multi-channel repetition controller of claim 5, wherein, all time delay modules implemented in all parallel branches have a delay of , the gain implemented by the repetitive control gain module in any th parallel branch is , the gain implemented by the positive feedforward gain module in any th parallel branch is , is a parameter and , ; in, and Both are positive integers, and When it is an even number, ; When it is an odd number, , Indicates to Rounding down, the general-purpose multi-channel repetitive controller is used to eliminate all subharmonics.

7. The universal multi-channel repetition controller of claim 5, wherein, Any number The gain achieved by the repetitive control gain module in each parallel branch is: , any number The gain achieved by the positive feedforward gain module in each parallel branch is: , any number The delay implemented by the time delay module in each parallel branch is: ; For parameters and , and All are arbitrary positive integers. The general-purpose multi-channel repetitive controller is used to eliminate specified harmonics and the gain of each harmonic has independent adjustment function.

8. The universal multi-channel repetition controller according to claim 5, characterized in that, Any of the periodic signal generators with parallel branches In this case, the input end of the time delay module , the output end of the positive feedforward gain module , the output end of the time delay module , the output end of the time delay module , the output end of the time delay module are respectively connected with low-pass filters ; and the output end of the addition ring is connected with the output end of the universal multi-channel repetitive controller through a phase lead compensator . Or, any of the periodic signal generators of parallel branches The input end of the time delay module The output end of the positive feedforward gain module The output end of the time delay module The output end of the time delay module The output end of the time delay module The output end of the time delay module ; and all the time delay modules in all the parallel branches are also controlled by the time delay damping coefficient ; wherein, is a parameter and .

9. The universal multi-channel repetition controller of claim 1, wherein, The output terminal of the repetitive control gain module is connected in series with the output terminal of the general-purpose multi-channel repetitive controller. Periodic signal generator: The output of the repetitive control gain module is connected to a positive input of a summing loop The output of the summing loop is connected to an input of a first order periodic signal generator The output of the first order periodic signal generator is connected to an input of an arbitrary order periodic signal generator The output of the arbitrary order periodic signal generator is connected to an input of a next order periodic signal generator The output of the next order periodic signal generator is connected to an input of a next order periodic signal generator The output of the next order periodic signal generator is connected to a positive input of a summing loop The output of the summing loop is connected to an input of a first order periodic signal generator The output of the first order periodic signal generator is connected to an input of an arbitrary order periodic signal generator The output of the arbitrary order periodic signal generator is connected to a positive input of a summing loop The output of the summing loop is connected to an input of a first order periodic signal generator The output of the first order periodic signal generator is connected to an input of an arbitrary order periodic signal generator The output of the arbitrary order periodic signal generator is connected to a positive input of a summing loop 10. The universal multi-channel repetition controller of claim 9, wherein, addition ring the output of the low pass filter and the phase lead compensator the output of the universal multi-channel repetition controller, the output of the low pass filter is connected to the addition ring another positive input of the addition ring the output of the low pass filter is connected to the addition ring .

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