Resonance suppression method and device for power generation system

Abstract

The invention provides a power generation system resonance suppression method and device, and belongs to the field of power system control. The method comprises the following steps: acquiring operation data of a grid-connected inverter in a target power generation system; determining a control signal of the grid-connected inverter according to the operation data and the active damping superposition control loop; performing resonance suppression in the target power generation system according to the control signal; wherein the active damping superposition control loop comprises a capacitance current feedback link and a capacitance voltage feedforward link; active damping corresponding to the resonant frequency of the grid-connected inverter is introduced into the grid-connected inverter in the capacitor current feedback link and the capacitor voltage feedforward link. On the basis of a capacitance current feedback link, a capacitance voltage feed-forward link is added, so that active damping generated by the capacitance current feedback link and the capacitance voltage feed-forward link is superposed, the active damping is increased, the resonance peak of the LCL filter is inhibited, and generated interference harmonic waves are reduced; therefore, the resonance point offset caused by the method is solved, and the resonance of the power generation system is inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of power system control, and in particular to a method and device for suppressing resonance of a power generation system. Background Art

[0002] The construction of power system has undergone a major transformation towards a new power system with a "high proportion of new energy" and a "high proportion of power electronics". Grid-connected inverters, as an interface device between the new energy power generation system and the power grid, are widely used in distributed energy systems.

[0003] In the power generation system, since the output voltage of the grid-connected inverter contains abundant high-frequency switching harmonics, a high-frequency filter needs to be added to suppress the grid-connected current harmonics. The LCL filter is more effective than the L filter, so an LCL type inverter is added between the inverter and the grid. As a third-order filter, the LCL filter takes into account the low-frequency high-efficiency filtering capability of the LC filter and also has the high-frequency attenuation capability. However, as a third-order underdamped system, it exhibits an inherent resonance peak, which seriously affects the stability of the grid-connected inverter, and then causes the power generation system to resonate. Summary of the invention

[0004] The embodiment of the present invention provides a method and device for suppressing resonance of a power generation system, so as to solve the problem that the stability of a grid-connected inverter is affected by the presence of harmonic peaks in an LCL filter.

[0005] In a first aspect, an embodiment of the present invention provides a method for suppressing resonance of a power generation system, comprising:

[0006] Obtaining operation data of grid-connected inverters in the target power generation system;

[0007] Determine the control signal of the grid-connected inverter based on the operating data and the active damping superposition control loop;

[0008] According to the control signal, resonance suppression is performed on the target power generation system;

[0009] The active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; both the capacitor current feedback link and the capacitor voltage feedforward link introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

[0010] In a possible implementation, the active damping superposition control loop includes a first inner open-loop transfer function or a second inner open-loop transfer function;

[0011] Based on the operating data and the active damping superposition control loop, the control signal of the grid-connected inverter is determined, including:

[0012] Inputting the operating data into an active damping superposition control loop, and determining a control signal of a grid-connected inverter based on a first inner open-loop transfer function;

[0013] Alternatively, the operating data is input into an active damping superposition control loop, and a control signal of the grid-connected inverter is determined based on a second inner open-loop transfer function.

[0014] In a possible implementation, the first inner open-loop transfer function is:

[0015]

[0016] Among them, G fb G is the active damping coefficient introduced into the capacitor current feedback link; ff is the active damping coefficient introduced in the capacitor voltage feedforward link; C is the filter capacitor; s is the resonant angular frequency; G d K is the delay in the sampling and calculation process of the power generation system during the PWM circuit; PWM is the inverter gain coefficient; H1 is the active damping coefficient introduced by capacitor current feedback; L1 is the inverter side inductance of the LCL filter; L2 is the grid side inductance; L g is the grid impedance.

[0017] In a possible implementation, the virtual impedance corresponding to the first inner open-loop transfer function is:

[0018]

[0019] The virtual impedance is determined by equivalently transforming the capacitor current feedback link and the capacitor voltage feedforward link.

[0020] In a possible implementation, the second inner open-loop transfer function is:

[0021]

[0022] Where N is the parameter corresponding to the corner frequency of the first-order high-pass filter in the case of fs / 2; ω r is the natural resonant frequency.

[0023] In a possible implementation, the equivalent transfer function corresponding to the second inner open-loop transfer function is:

[0024]

[0025] In a possible implementation, in the active damping superposition control loop corresponding to the first inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the first proportional link and the differential link connected in series.

[0026] In one possible implementation, in the active damping superposition control loop corresponding to the second inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the series connection of the first proportional link and the equivalent differential link; wherein the equivalent differential link is obtained by equivalently transforming the series structure of the first-order high-pass filter and the second proportional link within the Nyquist frequency.

[0027] In a possible implementation, the operating data includes input voltage, input current, input current reference value and grid voltage.

[0028] In a second aspect, an embodiment of the present invention provides a power generation system resonance suppression device, comprising:

[0029] A collection module, used to obtain the operating data of the grid-connected inverter in the target power generation system;

[0030] A calculation module for determining a control signal of a grid-connected inverter based on operating data and an active damping superposition control loop;

[0031] A control module, used for suppressing resonance of a target power generation system according to a control signal;

[0032] The active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; both the capacitor current feedback link and the capacitor voltage feedforward link introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

[0033] The embodiment of the present invention provides a method and device for suppressing resonance of a power generation system, taking into account that the active damping generated by the capacitor current feedback link in the original power generation system resonance suppression circuit is less than the resonance frequency of the corresponding grid-connected inverter, and is insufficient to suppress the resonance point offset caused by the LCL filter. The embodiment of the present invention adds a capacitor voltage feedforward link on the basis of the capacitor current feedback link, so that the active damping generated by the capacitor current feedback link and the capacitor voltage feedforward link are superimposed, and the active damping is increased to suppress the resonance peak of the LCL filter, reduce the interference harmonics generated by it, so as to solve the resonance point offset caused by it, thereby suppressing the resonance of the power generation system and improving the stability of the power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative work.

[0035] Figure 1 This is the main circuit topology diagram of the single-phase LCL grid-connected inverter;

[0036] Figure 2 It is an equivalent model of a single-phase LCL grid-connected inverter provided by an embodiment of the present invention;

[0037] Figure 3 is a flow chart of an implementation method of a power generation system resonance suppression method provided by an embodiment of the present invention;

[0038] Figure 4 It is a main circuit diagram of a single-phase LCL type grid-connected inverter with active damping superimposed on the output of a capacitor current feedback link and a capacitor voltage feedforward link provided by an embodiment of the present invention;

[0039] Figure 5 It is an equivalent model of a single-phase LCL type grid-connected inverter with active damping superimposed on the output of the capacitor current feedback link and the capacitor voltage feedforward link provided by an embodiment of the present invention;

[0040] Figure 6 It is a main circuit diagram of a single-phase LCL type grid-connected inverter with active damping superposition output of an optimized capacitor current feedback link and a capacitor voltage feedforward link provided by an embodiment of the present invention;

[0041] Figure 7 It is an equivalent model of a single-phase LCL type grid-connected inverter with active damping superimposed on the output of the optimized capacitor current feedback link and capacitor voltage feedforward link provided by an embodiment of the present invention;

[0042] Figure 8 It is a schematic diagram of the structure of a power generation system resonance suppression device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0045] Figure 1 This is the main circuit topology diagram of the single-phase LCL grid-connected inverter. Figure 2 The single-phase LCL grid-connected inverter equivalent model provided by the embodiment of the present invention is shown below in combination with Figure 1 and Figure 2 The causes of the technical problem solved by this embodiment are analyzed.

[0046] exist Figure 1 In the figure, L1, L2, and C are the inverter-side inductance, grid-connected-side inductance, and filter capacitor of the LCL filter respectively; L g is the grid impedance; u dc is the DC side voltage; U g is the grid voltage; i c is the capacitor current; i L1 is the inverter current; i L2 is the grid-connected current; v inv is the inverter output voltage; v PCC is the voltage at the common coupling point. Figure 1 We can get:

[0047]

[0048] according to Figure 1 The topological structure given in and the corresponding relationship obtained can be obtained Figure 2 Equivalent model of single-phase LCL grid-connected inverter in.

[0049] Combining Formula 1 and Figure 2 , we can get the transfer function from the inverter output side voltage to the grid-connected side current:

[0050]

[0051] Among them, i L2 (s) is the grid-connected current; v inv (s) is the output voltage; L T =L1+L g ; s is the resonant angular frequency; ω r is the natural resonant frequency, and its expression is:

[0052] Based on formula (2) and Figure 2 It can be seen that the LCL filter has the characteristics of a third-order system. There is a resonance phenomenon between the filter capacitor and the filter inductor, and a resonance peak is generated at its resonant frequency. At the same time, a large interference harmonic is generated, which causes the output current of the grid-connected inverter to oscillate. In severe cases, it may even cause a significant decrease in the stability of the system. When the frequency is the resonant angular frequency s = jω r When 2 =-ω r 2 , G LCL If the denominator of (s) is zero, the amplitude will be infinite and the phase angle will jump by 180°.

[0053] In order to solve the problem that the harmonic peaks of the LCL filter affect the stability of the grid-connected inverter at this stage, this embodiment provides the following Figure 3 The solution shown.

[0054] Figure 3 is a flow chart of the implementation of the method for suppressing resonance of a power generation system provided by an embodiment of the present invention, such as Figure 1 As shown, the method includes:

[0055] Step 110: Acquire operation data of the grid-connected inverter in the target power generation system.

[0056] In this embodiment, the operation data of the grid-connected inverter may include input voltage, input current, input current reference value, grid voltage, capacitor current and capacitor voltage of the filter capacitor in the LCL filter, etc.

[0057] Step 120: Determine the control signal of the grid-connected inverter according to the operation data and the active damping superposition control loop. The active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; both the capacitor current feedback link and the capacitor voltage feedforward link introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

[0058] In this embodiment, considering that the active damping generated by the capacitor current feedback link in the original power generation system resonance suppression circuit is less than the resonance frequency of the corresponding grid-connected inverter, and is insufficient to suppress the resonance point offset caused by the LCL filter, the embodiment of the present invention improves the active damping superposition control loop, and superimposes the capacitor voltage feedforward link on the original capacitor current feedback link. When the operation data of the grid-connected inverter is input into the active damping superposition control loop, a control signal of the grid-connected inverter including superimposed active damping can be generated through these two links; wherein the superimposed active damping generated can correspond to the resonance frequency of the grid-connected inverter, so as to increase the active damping introduced into the grid-connected inverter, thereby suppressing the resonance peak of the LCL filter and reducing the interference harmonics generated by it.

[0059] Active damping uses state variable feedback to achieve a natural increase in damping. The damping at this time is called virtual damping. Because the system can have multiple state variables, there are also multiple ways of system feedback. Different forms correspond to different transfer functions, correspondingly:

[0060] In an optional embodiment, the active damping superposition control loop may include a first inner open-loop transfer function or a second inner open-loop transfer function.

[0061] Based on the operating data and the active damping superposition control loop, the control signal of the grid-connected inverter is determined, which may include:

[0062] The operating data is input into the active damping superposition control loop, and the control signal of the grid-connected inverter is determined based on the first inner loop open-loop transfer function.

[0063] Alternatively, the operating data is input into an active damping superposition control loop, and a control signal of the grid-connected inverter is determined based on a second inner open-loop transfer function.

[0064] In this embodiment, this embodiment can provide two different forms of active damping superposition control loops to solve the technical problem corresponding to the present application. Correspondingly, the inner loop open-loop transfer functions corresponding to the two different forms of active damping superposition control loops are different. Figure 4 and Figure 5 , the topological structure corresponding to the first inner open-loop transfer function is described:

[0065] like Figure 4 As shown, in this embodiment, in the active damping superposition control loop corresponding to the first inner loop open-loop transfer function, the capacitor voltage feedforward link is based on the first proportional link G ff With the differential link G fb Cs are connected in series. Among them, K PWM is the inverter gain factor, U tri is the carrier amplitude. G c (s) is a quasi proportional resonant (QPR) current controller, and its expression is:

[0066]

[0067] Among them, K p is the proportional gain; K r is the resonance coefficient; ω c is the controller bandwidth; ω0 is the fundamental angular frequency, 100πrad / s.

[0068] G d (s) is the calculation delay, modulation delay and sampling delay in the system during PWM sampling and calculation, and its expression is:

[0069]

[0070] Among them, T s The sampling period

[0071] Considering that the capacitor current feedback link and the capacitor voltage feedforward link can have various forms, this embodiment provides

[0072] G LCL (s) is the transfer function of the LCL filter under the active damping superposition control strategy, and the corresponding expression of the system gain T(s) is:

[0073] T(s)=G c K PWM Gd G LCL (s)(5)

[0074] based on Figure 4 , and the corresponding parameters mentioned above, the first inner loop open-loop transfer function can be:

[0075]

[0076] Among them, G fb G is the active damping coefficient introduced into the capacitor current feedback link; ff The active damping coefficient introduced for the capacitor voltage feed-forward link.

[0077] based on Figure 4 The structure of one of its corresponding equivalent circuit diagrams can be found in Figure 5 ,exist Figure 5 In, Z eq1 , Z eq2 It is a virtual impedance, which is obtained by equivalently transforming the capacitor current feedback link and the capacitor voltage feedforward link respectively, and is connected in parallel at both ends of the filter capacitor.

[0078] Correspondingly, the virtual impedance can be expressed as:

[0079]

[0080] exist Figure 5 In the equation, the equivalent impedance is Z eq1 Parallel Z eq2 , the equivalent resistance is R eq1 Parallel R eq2 , the equivalent reactance is X eq1 Parallel X eq2 , whose expressions are:

[0081] Z eq =Z eq1 / / Z eq2 (9)

[0082] R eq =R eq1 / / R eq2 (10)

[0083] X eq =X eq1 / / X eq2 (11)

[0084] It should be understood that Figure 5 Only show Figure 4 The corresponding equivalent circuit is one of them, which does not constitute any limitation on this scheme. Figure 4 Other equivalent circuits that can be determined are also within the protection scope of the embodiments of the present invention.

[0085] Figure 4 The active damping superposition control loop provided can greatly improve the equivalent resistance R eq Positive damping range. However, due to the introduction of the capacitor voltage feedforward link, two sets of sensors are required, which is one more set than the traditional capacitor current feedback link, increasing the cost. Taking this into account, the second active damping superposition control loop also provided in this embodiment is improved on the basis of the first active damping superposition control loop, which can not only solve the technical problems proposed in the embodiment of the present invention, but also solve the high cost problem existing in the first active damping superposition control loop. Accordingly, the main circuit topology diagram of the second active damping superposition control loop can be seen in Figure 6 , Figure 6 The corresponding equivalent circuit diagram can be found in Figure 7 The following combination Figure 6 and Figure 7 The second active damping superposition control loop provided in this embodiment is described.

[0086] like Figure 6 As shown, in this embodiment, the capacitor voltage feedforward link in the active damping superposition control loop is optimized, and the differential link in the capacitor voltage feedforward link corresponding to the original first active damping superposition control loop is optimized, that is, the original differential link G fb Cs is replaced by an equivalent differential link obtained by equivalently transforming the series structure of the first-order high-pass filter and the second proportional link within the Nyquist frequency, such as Figure 5 As shown, the transfer function corresponding to the equivalent differential link can be expressed as:

[0087]

[0088] N=πf s (13)

[0089] Where N is the parameter corresponding to the corner frequency of the first-order high-pass filter in the case of fs / 2. Correspondingly, the capacitor voltage feedforward link at this time can be expressed as: G c (s) = G fb CF v (s)+G ff

[0090] Accordingly, at this time Figure 6 The corresponding second inner open-loop transfer function can be expressed as:

[0091]

[0092] right Figure 6 By performing an equivalent transformation on the structure in, we can obtain Figure 7In the equivalent model. Figure 7 In the transformed system structure, the structure consists of the capacitor voltage inner loop and the grid-connected current feedback outer loop. The corresponding inner loop closed-loop transfer function can be expressed as:

[0093]

[0094] The gain at this time is:

[0095]

[0096] From formula (16), we can see that at this time the current controller G c (s) does not have a right half plane pole, so whether T(s) has a right half plane pole depends on the inner loop closed-loop transfer function Q ic (s) Whether there are right half-plane poles.

[0097] Accordingly, based on Figure 7 The equivalent transfer function corresponding to the second inner open-loop transfer function is obtained as follows:

[0098]

[0099] From formula (17), we know that the parameter N of the first-order high-pass filter is a positive real number greater than 0, so there is no right half plane pole in the system, and P = 0. According to the Nyquist stability criterion, when P = 0, the positive crossing number M+ should be equal to the negative crossing number M-, and the system is stable.

[0100] It should be understood that Figure 7 and its corresponding equivalent transfer function is simply Figure 6 And one of the forms of the corresponding second inner-loop open-loop transfer function does not constitute any limitation on the second inner-loop open-loop transfer function. In addition, it should be understood that other forms of equivalent transfer functions determined based on the second inner-loop open-loop equivalent transfer function are also within the protection scope of the embodiments of the present invention.

[0101] Step 130: Perform resonance suppression on the target power generation system according to the control signal.

[0102] In this embodiment, the corresponding control signal obtained based on the active damping superposition control loop provided in step 120 of this embodiment is able to solve the technical problem solved by this embodiment. Therefore, the grid-connected inverter can be directly controlled through the obtained control signal to solve the resonance point offset problem caused by the LCL filter, thereby suppressing the resonance of the power generation system and improving the stability of the power generation system.

[0103] In summary, the embodiment of the present invention takes into account that the active damping generated by the capacitor current feedback link in the original power generation system resonance suppression circuit is less than the resonance frequency of the corresponding grid-connected inverter, and is insufficient to suppress the resonance point offset caused by the LCL filter. The embodiment of the present invention adds a capacitor voltage feedforward link on the basis of the capacitor current feedback link, so that the active damping generated by the capacitor current feedback link and the capacitor voltage feedforward link are superimposed, and the active damping is increased to suppress the resonance peak of the LCL filter, reduce the interference harmonics generated by it, so as to solve the resonance point offset caused by it, and then suppress the resonance of the power generation system and improve the stability of the power generation system.

[0104] In another optional embodiment, the parameters of the grid-connected inverter are set as follows:

[0105] DC side voltage u dc =220V; grid voltage u g =50V; inverter side inductance L1 = 3.5mH; grid side inductance L2 = 1.75mH; grid impedance L g =(0-5)mH; filter capacitor C = 5μF; DC gain K PWM =100; proportionality coefficient K p =0.06; resonance coefficient K r =5; sampling frequency f s =10kHz; switching frequency f sw =10kHz.

[0106] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0107] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0108] Figure 8 The structure diagram of the power generation system resonance suppression device provided by the embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0109] like Figure 8 As shown, the power generation system resonance suppression device 8 includes:

[0110] The acquisition module 81 is used to obtain the operation data of the grid-connected inverter in the target power generation system;

[0111] A calculation module 82, for determining a control signal of a grid-connected inverter based on the operating data and the active damping superposition control loop;

[0112] A control module 83, used for suppressing resonance of a target power generation system according to a control signal;

[0113] The active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; both the capacitor current feedback link and the capacitor voltage feedforward link introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

[0114] In a possible implementation, the active damping superposition control loop includes a first inner open-loop transfer function or a second inner open-loop transfer function;

[0115] The calculation module 82 is specifically used for:

[0116] Inputting the operating data into an active damping superposition control loop, and determining a control signal of a grid-connected inverter based on a first inner open-loop transfer function;

[0117] Alternatively, the operating data is input into an active damping superposition control loop, and a control signal of the grid-connected inverter is determined based on a second inner open-loop transfer function.

[0118] In a possible implementation, the first inner open-loop transfer function is:

[0119]

[0120] Among them, G fb G is the active damping coefficient introduced into the capacitor current feedback link; ff is the active damping coefficient introduced in the capacitor voltage feedforward link; C is the filter capacitor; s is the resonant angular frequency; G d K is the delay in the sampling and calculation process of the power generation system during the PWM circuit; PWM is the inverter gain coefficient; H1 is the active damping coefficient introduced by capacitor current feedback; L1 is the inverter side inductance of the LCL filter; L2 is the grid side inductance; L g is the grid impedance.

[0121] In a possible implementation, the virtual impedance corresponding to the first inner open-loop transfer function is:

[0122]

[0123] The virtual impedance is determined by equivalently transforming the capacitor current feedback link and the capacitor voltage feedforward link.

[0124] In a possible implementation, the second inner open-loop transfer function is:

[0125]

[0126] Where N is the parameter corresponding to the corner frequency of the first-order high-pass filter in the case of fs / 2; ω r is the natural resonant frequency.

[0127] In a possible implementation, the equivalent transfer function corresponding to the second inner open-loop transfer function is:

[0128]

[0129] In a possible implementation, in the active damping superposition control loop corresponding to the first inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the first proportional link and the differential link connected in series.

[0130] In one possible implementation, in the active damping superposition control loop corresponding to the second inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the series connection of the first proportional link and the equivalent differential link; wherein the equivalent differential link is obtained by equivalently transforming the series structure of the first-order high-pass filter and the second proportional link within the Nyquist frequency.

[0131] In a possible implementation, the operating data includes input voltage, input current, input current reference value and grid voltage.

[0132] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0133] Those of ordinary skill in the art will appreciate that the templates, units, and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0134] If the module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various power generation system resonance suppression method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium.

[0135] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for suppressing resonance of a power generation system, characterized in that: include: Obtaining operation data of grid-connected inverters in the target power generation system; Determining a control signal of the grid-connected inverter according to the operating data and an active damping superposition control loop; According to the control signal, resonance suppression is performed on the target power generation system; Among them, the active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; the capacitor current feedback link and the capacitor voltage feedforward link both introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

2. The method for suppressing resonance of a power generation system according to claim 1, characterized in that: The active damping superposition control loop includes a first inner open-loop transfer function or a second inner open-loop transfer function; Determining the control signal of the grid-connected inverter according to the operating data and the active damping superposition control loop includes: Inputting the operating data into an active damping superposition control loop, and determining a control signal of the grid-connected inverter based on a first inner open-loop transfer function; Alternatively, the operating data is input into an active damping superposition control loop, and a control signal of the grid-connected inverter is determined based on a second inner open-loop transfer function.

3. The method for suppressing resonance of a power generation system according to claim 2, characterized in that: The first inner open-loop transfer function is: Among them, G fb G is the active damping coefficient introduced into the capacitor current feedback link; ff is the active damping coefficient introduced in the capacitor voltage feedforward link; C is the filter capacitor; s is the resonant angular frequency; G d K is the delay in the sampling and calculation process of the power generation system during the PWM circuit; PWM is the inverter gain coefficient; H1 is the active damping coefficient introduced by capacitor current feedback; L1 is the inverter side inductance of the LCL filter; L2 is the grid side inductance; L g is the grid impedance.

4. The method for suppressing resonance of a power generation system according to claim 3, characterized in that: The virtual impedance corresponding to the first inner open-loop transfer function is: The virtual impedance is determined by performing equivalent transformation on the capacitor current feedback link and the capacitor voltage feedforward link.

5. The method for suppressing resonance of a power generation system according to claim 2, characterized in that: The second inner open-loop transfer function is: Where N is the parameter corresponding to the corner frequency of the first-order high-pass filter in the case of fs / 2; ω r is the natural resonant frequency.

6. The method for suppressing resonance of a power generation system according to claim 5, characterized in that: The equivalent transfer function corresponding to the second inner open-loop transfer function is:

7. The method for suppressing resonance of a power generation system according to claim 2, characterized in that: In the active damping superposition control loop corresponding to the first inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the first proportional link and the differential link connected in series.

8. The method for suppressing resonance of a power generation system according to claim 2, characterized in that: In the active damping superposition control loop corresponding to the second inner open-loop transfer function, the capacitor voltage feedforward link is obtained based on the series connection of the first proportional link and the equivalent differential link; wherein the equivalent differential link is obtained by equivalently transforming the series structure of the first-order high-pass filter and the second proportional link within the Nyquist frequency.

9. The method for suppressing resonance of a power generation system according to claim 1, characterized in that: The operation data includes input voltage, input current, input current reference value and grid voltage.

10. A power generation system resonance suppression device, characterized in that: include: A collection module, used to obtain the operating data of the grid-connected inverter in the target power generation system; A calculation module, used for determining a control signal of the grid-connected inverter according to the operation data and an active damping superposition control loop; A control module, configured to suppress resonance of the target power generation system according to the control signal; Among them, the active damping superposition control loop includes a capacitor current feedback link and a capacitor voltage feedforward link; the capacitor current feedback link and the capacitor voltage feedforward link both introduce active damping corresponding to the resonant frequency of the grid-connected inverter into the grid-connected inverter.

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