Inverter based on coupling structure and parameter calculation method, device and equipment thereof

Abstract

The present application relates to an inverter based on a coupling structure and a parameter calculation method, device and equipment thereof, the method comprising obtaining the control parameters of the inverter and the harmonic order of the load; obtaining reactive compensation data according to the fundamental frequency, initial capacitance and initial inductance calculation; obtaining the upper limit of harmonic compensation according to the reactive compensation data, grid connection point voltage, sampling period, resonance ratio and transfer function threshold calculation; determining the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the upper limit of harmonic compensation; obtaining the capacitance and inductance of the coupling structure connected to the inverter according to the fundamental frequency, reactive compensation data, grid connection point voltage and coupling impedance to the fundamental frequency data. The capacitance and inductance of the coupling structure connected to the inverter are obtained by the inverter parameter calculation method based on the coupling structure as the design parameters of the inverter, so that the designed inverter can realize wide-band harmonic compensation and improve the harmonic compensation capability of the inverter.

Description

Technical Field

[0001] The present application relates to the technical field of inverters, and in particular to an inverter based on a coupling structure and a parameter calculation method, device and equipment thereof. Background Art

[0002] Due to the inherent control disadvantages of semiconductor materials and the increasing number of nonlinear loads connected, serious harmonic problems will occur in power networks containing distributed energy. Since harmonics will increase the loss of the power system and cause interference and failure to other electrical equipment on the power system, the control of harmonics has received more and more attention. Harmonic compensation is a very common control method. Existing harmonic compensation equipment includes active power filters and passive filters. Active power filters have strong filtering capabilities and their control capabilities are less affected by power system parameters; but they are expensive and have complex control methods. Generally, multiple quasi-proportional-resonant controllers are required to achieve compensation for multiple harmonic frequency bands, which requires additional configuration and requires additional power supply, resulting in high operating costs. Passive filters are low in cost and do not require additional power supply, but their ability to filter harmonics is limited and can only filter harmonics of specific frequencies; it is difficult to coordinate reactive compensation and harmonic control functions, and it is difficult to set power system parameters. Summary of the invention

[0003] The embodiments of the present application provide an inverter based on a coupling structure and a parameter calculation method, device and equipment thereof, which are used to solve the technical problem that the existing passive harmonic compensation equipment can only filter out characteristic harmonics and has poor harmonic compensation effect.

[0004] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions:

[0005] A method for calculating inverter parameters based on a coupling structure is applied to an inverter based on a coupling structure. The method for calculating inverter parameters comprises the following steps:

[0006] Acquiring control parameters of the inverter and harmonic order of the load, wherein the control parameters include fundamental frequency, grid connection point voltage, initial capacitance, initial inductance, sampling period, resonance ratio and transfer function threshold, and the load is connected to the inverter;

[0007] According to the fundamental frequency, the initial capacitance and the initial inductance, reactive compensation data is obtained; according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold, an upper limit of harmonic compensation is obtained;

[0008] Determine the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the harmonic compensation upper limit order;

[0009] The base frequency data is calculated according to the base frequency, the reactive power compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter.

[0010] Preferably, the inverter parameter calculation method based on the coupling structure includes: using a capacitance calculation formula and an inductance calculation formula to calculate the base frequency data according to the base frequency, the reactive compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter; the capacitance calculation formula is:

[0011]

[0012] The inductance calculation formula is:

[0013]

[0014] Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the fundamental frequency, N is the coupling impedance to the fundamental frequency data, L is the inductance of the coupling structure connected to the inverter, and C is the capacitance of the coupling structure connected to the inverter.

[0015] Preferably, the inverter parameter calculation method based on the coupling structure includes: using a harmonic compensation upper limit order calculation formula to calculate the harmonic compensation upper limit order according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold, to obtain the harmonic compensation upper limit order; the harmonic compensation upper limit order calculation formula is:

[0016]

[0017] In the formula, H U is the upper limit of harmonic compensation, V pcc is the grid voltage, Q s is the reactive compensation data, ω is the fundamental frequency, T is the sampling period, K is the resonance ratio, and α is the transfer function threshold.

[0018] Preferably, the inverter parameter calculation method based on the coupling structure includes: using a reactive compensation calculation formula to calculate according to the fundamental frequency, the initial capacitance and the initial inductance to obtain reactive compensation data; the reactive compensation calculation formula is:

[0019]

[0020] Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the fundamental frequency, C0 is the initial capacitance, and L0 is the initial inductance.

[0021] Preferably, acquiring the harmonic order of the load connected to the inverter includes: determining the harmonic order according to the type of the load connected to the inverter.

[0022] The present application also provides an inverter based on a coupling structure, comprising a power input terminal, a control module, an LC coupling module and a load connection module connected in sequence, wherein the capacitance and inductance of the LC coupling module are obtained using the inverter parameter calculation method based on the coupling structure described above.

[0023] Preferably, the LC coupling module includes three groups of LC circuits, the input end of each group of LC circuits is connected to an output end of the control module, and the output end of each group of LC circuits is connected to an input end of the load connection module; each group of LC circuits includes an inductor, a capacitor and a resistor connected in series in sequence.

[0024] The present application also provides an inverter parameter calculation device based on a coupling structure, which is applied to an inverter based on a coupling structure. The inverter parameter calculation device includes a data acquisition module, a first calculation module, a data determination module and a second calculation module;

[0025] The data acquisition module is used to acquire control parameters of the inverter and harmonic order of the load, wherein the control parameters include fundamental frequency, grid connection point voltage, initial capacitance, initial inductance, sampling period, resonance ratio and transfer function threshold, and the load is connected to the inverter;

[0026] The first calculation module is used to calculate the reactive compensation data by using the reactive compensation calculation formula according to the fundamental frequency, the initial capacitance and the initial inductance; and to calculate the harmonic compensation upper limit order by using the harmonic compensation upper limit order calculation formula according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold;

[0027] The data determination module is used to determine the coupling impedance to fundamental frequency data of the coupling structure in the inverter according to the harmonic order and the harmonic compensation upper limit order;

[0028] The second calculation module is used to calculate the base frequency data using the capacitance calculation formula and the inductance calculation formula according to the base frequency, the reactive compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter.

[0029] Preferably, the capacitance calculation formula is:

[0030]

[0031] The inductance calculation formula is:

[0032]

[0033] The calculation formula for the upper limit of harmonic compensation is:

[0034]

[0035] The reactive power compensation calculation formula is:

[0036]

[0037] Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the base frequency, N is the coupling impedance to the base frequency data, L is the inductance of the coupling structure connected to the inverter, C is the capacitance of the coupling structure connected to the inverter, H U is the upper limit of harmonic compensation, T is the sampling period, K is the resonance ratio, α is the transfer function threshold, C0 is the initial capacitance, and L0 is the initial inductance.

[0038] The present application also provides a terminal device, including a processor and a memory;

[0039] The memory is used to store program codes and transmit the program codes to the processor;

[0040] The processor is used to execute the above-mentioned inverter parameter calculation method based on the coupling structure according to the instructions in the program code.

[0041] It can be seen from the above technical scheme that the embodiment of the present application has the following advantages: the inverter based on the coupling structure and its parameter calculation method, device and equipment, the method includes obtaining the control parameters of the inverter and the harmonic order of the load; according to the fundamental frequency, initial capacitance and initial inductance calculation, reactive compensation data is obtained; according to the reactive compensation data, grid connection point voltage, sampling period, resonance ratio and transfer function threshold calculation, the harmonic compensation upper limit is obtained; according to the harmonic order and the harmonic compensation upper limit, the coupling impedance of the coupling structure in the inverter is determined to the fundamental frequency data; according to the fundamental frequency, reactive compensation data, grid connection point voltage and coupling impedance, the fundamental frequency data is calculated to obtain the capacitance and inductance of the coupling structure connected in the inverter. The capacitance and inductance of the coupling structure connected are obtained as the design parameters of the inverter through the inverter parameter calculation method based on the coupling structure, so that the designed inverter can realize wide-band harmonic compensation, improve the harmonic compensation capability of the inverter, and solve the technical problem that the existing passive harmonic compensation equipment can only filter out characteristic harmonics and the harmonic compensation effect is poor. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 A flowchart of the steps of the inverter parameter calculation method based on the coupling structure described in an embodiment of the present application;

[0044] Figure 2 It is a schematic diagram of a framework of an inverter based on a coupling structure in a method for calculating inverter parameters based on a coupling structure according to an embodiment of the present application;

[0045] Figure 3 A schematic diagram of an inverter control system based on a coupling structure in an inverter parameter calculation method based on a coupling structure according to an embodiment of the present application;

[0046] Figure 4 It is a framework diagram of an inverter parameter calculation device based on a coupling structure according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] The embodiments of the present application provide an inverter based on a coupling structure and a parameter calculation method, device and equipment thereof, which are used to solve the technical problem that the existing passive harmonic compensation equipment can only filter out characteristic harmonics and has poor harmonic compensation effect.

[0049] Embodiment 1:

[0050] Figure 1 This is a flowchart of the steps of the inverter parameter calculation method based on the coupling structure described in an embodiment of the present application. Figure 2 Schematic diagram of a framework of an inverter based on a coupling structure in a method for calculating inverter parameters based on a coupling structure according to an embodiment of the present application, Figure 3 Schematic diagram of an inverter control system based on a coupling structure in the inverter parameter calculation method based on a coupling structure described in an embodiment of the present application. Figure 3 The letters in the list mean: S aThe beginning is the trigger signal for the IGBT switch in the inverter, i c is the sampling current, i L is the current flowing to the load by the inverter control system based on the coupling structure, i s The current output by the AC power supply.

[0051] The embodiment of the present application provides a method for calculating inverter parameters based on a coupling structure, which is applied to an inverter based on a coupling structure.

[0052] like Figure 2 As shown, in the embodiment of the present application, the inverter based on the coupling structure includes a power input terminal 10, a control module 20, an LC coupling module 30 and a load connection module 40 connected in sequence, and the capacitance and inductance of the LC coupling module 30 are obtained by using the inverter parameter calculation method based on the coupling structure. The LC coupling module 30 includes three groups of LC circuits, the input end of each group of LC circuits is connected to an output end of the control module 20, and the output end of each group of LC circuits is connected to an input end of the load connection module 40; each group of LC circuits includes an inductor, a capacitor and a resistor connected in series in sequence.

[0053] It should be noted that the load connection module 40 includes three input terminals, which are respectively denoted as port A, port B and port C, and port A, port B and port C are all connected to an output terminal of the LC coupling module 30. In this embodiment, the control module 20 includes at least six IGBT tubes.

[0054] In the embodiments of the present application, Figure 3 As shown, the inverter control system based on the coupling structure is: connecting port 1 of the AC power supply to port 1 of the load, port 2 of the inverter based on the coupling structure and port 1 of the quasi-proportional-resonant controller respectively, connecting port 3 of the quasi-proportional-resonant controller to one end of the carrier PWM controller, and connecting the other end of the carrier PWM controller to port 3 of the inverter based on the coupling structure, connecting port 1 of the inverter based on the coupling structure to port 2 of the AC power supply and port 2 of the load respectively, connecting port 2 of the quasi-proportional-resonant oscillator to port 1 of the power calculation unit, and the power calculation unit is used to input electrical quantity parameters through its input terminal, and the electrical quantity parameters include the active power P output by the inverter inj , load current iL, grid voltage V PCC The inverter control system based on the coupling structure obtains the reference current value i of the input quasi-proportional-resonant controller by calculating the instantaneous reactive power formula according to the input electrical quantity parameters through the power calculation unit. c_ref The quasi-proportional-resonant controller is based on the reference current value i c_refThe current reference value that can control the power output of the inverter is calculated, and the carrier PWM controller compiles the carrier signal according to the current reference value.

[0055] In an embodiment of the present application, the inverter control system based on the coupling structure is connected to the low-voltage bus through an LC coupling module and cooperates with a single quasi-proportional-resonant controller to achieve effective harmonic compensation for the harmonics generated by nonlinear elements, and at the same time suppress the ripple current generated by the inverter. Compared with the traditional harmonic compensation scheme, the inverter control system based on the coupling structure can greatly reduce the complexity of the control algorithm and the requirements for the computing power of the control chip by using the inverter based on the coupling structure of the present application, thereby reducing costs, controlling losses, and extending the life of the equipment. At the same time, the LC coupling module can also help maintain the grid connection point voltage and improve the power supply reliability, and the inverter parameter calculation method based on the coupling structure can be applied to the design of core inverters of renewable energy, such as wind power, solar power and other power generation equipment, to improve the power quality of new energy power generation.

[0056] It should be noted that the inverter control system based on the coupling structure suppresses low-frequency harmonics through the capacitive coupling structure of the LC coupling module in the inverter, and compensates for high-frequency harmonics through a quasi-proportional-resonant controller.

[0057] like Figure 1 As shown, the inverter parameter calculation method based on the coupling structure includes the following steps:

[0058] S1. Obtain control parameters of the inverter and harmonic order of the load, the control parameters include fundamental frequency, grid connection point voltage, initial capacitance, initial inductance, sampling period, resonance ratio and transfer function threshold, and the load is connected to the inverter.

[0059] It should be noted that in step S1, one is to obtain the harmonic order of the load connected to the inverter; the other is to obtain the control parameters for controlling the operation of the inverter.

[0060] In the embodiment of the present application, obtaining the harmonic order of the load connected to the inverter includes: determining the harmonic order according to the type of the load connected to the inverter.

[0061] It should be noted that if the load type is a capacitor load, generating 5-7 harmonics, the harmonic order can be selected as 7; if the load type is a power semiconductor device, generating 5-11 harmonics, the harmonic order can be selected as 11. Among them, the rule for obtaining the harmonic order value of the inverter parameter calculation method based on the coupling structure is to select the highest value.

[0062] S2. Obtain reactive power compensation data based on fundamental frequency, initial capacitance and initial inductance; obtain upper limit of harmonic compensation based on reactive power compensation data, grid connection point voltage, sampling period, resonance ratio and transfer function threshold.

[0063] It should be noted that in step S2, reactive power compensation data and the upper limit of harmonic compensation times are calculated.

[0064] In the embodiment of the present application, the inverter parameter calculation method based on the coupling structure adopts the harmonic compensation upper limit order calculation formula to calculate the harmonic compensation upper limit order; and adopts the reactive compensation calculation formula to calculate the reactive compensation data;

[0065] The reactive power compensation calculation formula is:

[0066]

[0067] The calculation formula for the upper limit of harmonic compensation is:

[0068]

[0069] In the formula, H U is the upper limit of harmonic compensation, V pcc is the grid voltage, Q s is the reactive compensation data, ω is the fundamental frequency, T is the sampling period, K is the resonance ratio, α is the transfer function threshold, C0 is the initial capacitance, and L0 is the initial inductance.

[0070] It should be noted that in order to avoid current amplification at high frequencies, it is necessary to set a threshold α for the closed-loop transfer function size of the proportional-resonant controller. For example: for low voltages below 10kV, select α as 10dB, for 10-15kV, select α as 20dB, and for 15-25kV, select α as 30dB.

[0071] In the embodiment of the present application, the following inequality can be obtained according to the transfer function threshold α and the closed-loop transfer function of the proportional-resonant controller:

[0072]

[0073] Where, T is the sampling period of the carrier PWM controller in the inverter control system based on the coupling structure, K is the proportional term of the proportional-resonant controller (i.e., the resonant proportion), and in the low-voltage network, K can be between 40 and 60. Considering that for harmonics with a harmonic order of more than 3, φ real (ω) and φ img (ω) is a parameter, φ real (ω) and φ img The value of (ω) is a relatively small value, so the above inequality can be simplified to:

[0074]

[0075] S3. Determine the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the upper limit order of harmonic compensation.

[0076] It should be noted that in step S3, the harmonic order H obtained in step S1 and step S2 is L The upper limit of harmonic compensation is H U , select the coupling impedance to the fundamental frequency data. The selected coupling impedance to the fundamental frequency data N is greater than the harmonic order H L And less than the upper limit of harmonic compensation H U In this embodiment, the closer the value of the coupling impedance to the fundamental frequency data N is to the upper limit of the harmonic compensation order H U , the higher the value of coupling impedance for the fundamental frequency data N, the more likely the high-frequency ripple will be amplified, but the low-order harmonic compensation effect will be better; the closer the value of coupling impedance to the harmonic order H L , the higher the high-frequency ripple will be effectively compensated, but the compensation effect of low-order harmonics will be affected. The selection should be made according to the actual harmonic type of the load and the proportion of different harmonics.

[0077] S4. Calculate the base frequency data according to the base frequency, reactive power compensation data, grid connection point voltage and coupling impedance to obtain the capacitance and inductance of the coupling structure connected in the inverter.

[0078] It should be noted that in step S4, the capacitance and inductance connected to the coupling structure in the inverter are calculated.

[0079] In the embodiment of the present application, the capacitance and inductance of the coupling structure connected in the inverter are calculated using the capacitance calculation formula and the inductance calculation formula; the capacitance calculation formula is:

[0080]

[0081] The formula for calculating inductance is:

[0082]

[0083] Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the fundamental frequency, N is the coupling impedance to the fundamental frequency data, L is the inductance of the coupling structure connected to the inverter, and C is the capacitance of the coupling structure connected to the inverter.

[0084] In an embodiment of the present application, the capacitance and inductance of the LC coupling module are calculated by a method for calculating inverter parameters based on a coupling structure to design an inverter, and wide-band harmonic compensation can be achieved through the compensation effect of the LC coupling module of the inverter on harmonics. In addition, since the inverter based on the coupling structure is a passive filtering device, no additional power supply is required, thereby reducing operating costs.

[0085] The present application provides a method for calculating inverter parameters based on a coupling structure, the method comprising obtaining control parameters of the inverter and the harmonic order of the load; obtaining reactive compensation data according to fundamental frequency, initial capacitance and initial inductance calculation; obtaining the upper limit of harmonic compensation according to reactive compensation data, grid connection point voltage, sampling period, resonance ratio and transfer function threshold calculation; determining the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the upper limit of harmonic compensation; obtaining the capacitance and inductance of the coupling structure connected to the inverter according to the fundamental frequency, reactive compensation data, grid connection point voltage and coupling impedance to the fundamental frequency data. The capacitance and inductance of the coupling structure connected to the inverter are obtained by the inverter parameter calculation method based on the coupling structure as the design parameters of the inverter, so that the designed inverter can realize wide-band harmonic compensation, improve the harmonic compensation capability of the inverter, and solve the technical problem that the existing passive harmonic compensation equipment can only filter out characteristic harmonics and the harmonic compensation effect is poor.

[0086] Embodiment 2:

[0087] Figure 4 This is a framework flow chart of the inverter parameter calculation device based on the coupling structure described in an embodiment of the present application.

[0088] like Figure 4 As shown, an embodiment of the present application provides an inverter parameter calculation device based on a coupling structure, which is applied to an inverter based on a coupling structure. The inverter parameter calculation device includes: a data acquisition module 10, a first calculation module 20, a data determination module 30 and a second calculation module 40;

[0089] The data acquisition module 10 is used to acquire the control parameters of the inverter and the harmonic order of the load, the control parameters include the fundamental frequency, the grid connection point voltage, the initial capacitance, the initial inductance, the sampling period, the resonance ratio and the transfer function threshold, and the load is connected to the inverter;

[0090] The first calculation module 20 is used to calculate the reactive power compensation data by using the reactive power compensation calculation formula according to the fundamental frequency, the initial capacitance and the initial inductance; and to calculate the harmonic compensation upper limit order by using the harmonic compensation upper limit order calculation formula according to the reactive power compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold;

[0091] A data determination module 30, for determining the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the upper limit order of the harmonic compensation;

[0092] The second calculation module 40 is used to calculate the base frequency data using the capacitance calculation formula and the inductance calculation formula according to the base frequency, reactive compensation data, grid connection point voltage and coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter.

[0093] In the embodiment of the present application, the capacitance calculation formula is:

[0094]

[0095] The formula for calculating inductance is:

[0096]

[0097] The calculation formula for the upper limit of harmonic compensation is:

[0098]

[0099] The reactive power compensation calculation formula is:

[0100]

[0101] Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the base frequency, N is the coupling impedance to the base frequency data, L is the inductance of the coupling structure connected to the inverter, C is the capacitance of the coupling structure connected to the inverter, H U is the upper limit of harmonic compensation, T is the sampling period, K is the resonance ratio, α is the transfer function threshold, C0 is the initial capacitance, and L0 is the initial inductance.

[0102] It should be noted that the modules in the device of Example 2 correspond to the steps in the method of Example 1. The content of the inverter parameter calculation method based on the coupling structure has been described in detail in Example 1, and the content of the modules in the device will not be described in detail in this Example 2.

[0103] Embodiment three:

[0104] An embodiment of the present application provides a terminal device, including a processor and a memory;

[0105] A memory, used for storing program codes and transmitting the program codes to a processor;

[0106] The processor is used to execute the above-mentioned inverter parameter calculation method based on the coupling structure according to the instructions in the program code.

[0107] It should be noted that the processor is used to execute the steps in the above-mentioned inverter parameter calculation method embodiment based on the coupling structure according to the instructions in the program code. Alternatively, the processor implements the functions of each module / unit in the above-mentioned system / device embodiments when executing the computer program.

[0108] Exemplarily, the computer program may be divided into one or more modules / units, one or more modules / units are stored in a memory and executed by a processor to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of completing a specific function, and the instruction segments are used to describe the execution process of the computer program in a terminal device.

[0109] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that this does not constitute a limitation on the terminal device, and may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal device may also include input and output devices, network access devices, buses, etc.

[0110] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0111] The memory may be an internal storage unit of the terminal device, such as a hard disk or memory of the terminal device. The memory may also be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the terminal device. Furthermore, the memory may also include both an internal storage unit of the terminal device and an external storage device. The memory is used to store computer programs and other programs and data required by the terminal device. The memory may also be used to temporarily store data that has been output or is to be output.

[0112] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0113] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0114] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0115] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0116] If the integrated 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 technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0117] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these 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 application.

Claims

1. A method for calculating inverter parameters based on a coupling structure, applied to an inverter based on a coupling structure, characterized in that: The inverter based on the coupling structure comprises a power input terminal, a control module, an LC coupling module and a load connection module connected in sequence, the LC coupling module comprises three groups of LC circuits, the input terminal of each group of the LC circuits is connected to an output terminal of the control module, and the output terminal of each group of the LC circuits is connected to an input terminal of the load connection module; each group of the LC circuits comprises an inductor, a capacitor and a resistor connected in series in sequence, and the inverter parameter calculation method comprises the following steps: Acquiring control parameters of the inverter and harmonic order of the load, wherein the control parameters include fundamental frequency, grid connection point voltage, initial capacitance, initial inductance, sampling period, resonance ratio and transfer function threshold, and the load is connected to the inverter; According to the fundamental frequency, the initial capacitance and the initial inductance, reactive compensation data is obtained; according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold, an upper limit of harmonic compensation is obtained; Determine the coupling impedance of the coupling structure in the inverter to the fundamental frequency data according to the harmonic order and the harmonic compensation upper limit order; The base frequency data is calculated according to the base frequency, the reactive power compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter.

2. The inverter parameter calculation method based on the coupling structure according to claim 1, characterized in that: include: Calculate the base frequency data using a capacitance calculation formula and an inductance calculation formula according to the base frequency, the reactive compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance of the coupling structure connected to the inverter; The capacitance calculation formula is: The inductance calculation formula is: Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the fundamental frequency, N is the coupling impedance to the fundamental frequency data, L is the inductance of the coupling structure connected to the inverter, and C is the capacitance of the coupling structure connected to the inverter.

3. The inverter parameter calculation method based on the coupling structure according to claim 1, characterized in that: include: The harmonic compensation upper limit order is calculated by using the harmonic compensation upper limit order calculation formula according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold, to obtain the harmonic compensation upper limit order; The calculation formula for the upper limit of harmonic compensation is: In the formula, H U is the upper limit of harmonic compensation, V pcc is the grid voltage, Q s is the reactive compensation data, ω is the fundamental frequency, T is the sampling period, K is the resonance ratio, and α is the transfer function threshold.

4. The inverter parameter calculation method based on the coupling structure according to claim 1, characterized in that: include: The reactive compensation data is obtained by using a reactive compensation calculation formula according to the fundamental frequency, the initial capacitance and the initial inductance; the reactive compensation calculation formula is: Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the fundamental frequency, C0 is the initial capacitance, and L0 is the initial inductance.

5. The inverter parameter calculation method based on the coupling structure according to claim 1, characterized in that: Acquiring the harmonic order of the load connected to the inverter includes: determining the harmonic order according to the type of the load connected to the inverter.

6. An inverter parameter calculation device based on a coupling structure, applied to an inverter based on a coupling structure, characterized in that: The inverter based on the coupling structure comprises a power input terminal, a control module, an LC coupling module and a load connection module connected in sequence, the LC coupling module comprises three groups of LC circuits, the input terminal of each group of the LC circuits is connected to an output terminal of the control module, and the output terminal of each group of the LC circuits is connected to an input terminal of the load connection module; each group of the LC circuits comprises an inductor, a capacitor and a resistor connected in series in sequence, and the inverter parameter calculation device comprises: a data acquisition module, a first calculation module, a data determination module and a second calculation module; The data acquisition module is used to acquire control parameters of the inverter and harmonic order of the load, wherein the control parameters include fundamental frequency, grid connection point voltage, initial capacitance, initial inductance, sampling period, resonance ratio and transfer function threshold, and the load is connected to the inverter; The first calculation module is used to calculate the reactive compensation data by using the reactive compensation calculation formula according to the fundamental frequency, the initial capacitance and the initial inductance; and to calculate the harmonic compensation upper limit order by using the harmonic compensation upper limit order calculation formula according to the reactive compensation data, the grid connection point voltage, the sampling period, the resonance ratio and the transfer function threshold; The data determination module is used to determine the coupling impedance to fundamental frequency data of the coupling structure in the inverter according to the harmonic order and the harmonic compensation upper limit order; The second calculation module is used to calculate the base frequency data using the capacitance calculation formula and the inductance calculation formula according to the base frequency, the reactive compensation data, the grid connection point voltage and the coupling impedance to obtain the capacitance and inductance connected to the coupling structure in the inverter.

7. The inverter parameter calculation device based on the coupling structure according to claim 6, characterized in that: The capacitance calculation formula is: The inductance calculation formula is: The calculation formula for the upper limit of harmonic compensation is: The reactive power compensation calculation formula is: Where V pcc is the grid voltage, Q s is the reactive power compensation data, ω is the base frequency, N is the coupling impedance to the base frequency data, L is the inductance of the coupling structure connected to the inverter, C is the capacitance of the coupling structure connected to the inverter, H U is the upper limit of harmonic compensation, T is the sampling period, K is the resonance ratio, α is the transfer function threshold, C0 is the initial capacitance, and L0 is the initial inductance.

8. A terminal device, characterized in that: including a processor and a memory; The memory is used to store program codes and transmit the program codes to the processor; The processor is used to execute the inverter parameter calculation method based on the coupling structure according to any one of claims 1 to 5 according to the instructions in the program code.

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