Inverter control method based on power grid, electronic equipment, storage medium and program product

Abstract

The embodiment of the invention provides an inverter control method based on a power grid, electronic equipment, a storage medium and a program product. The method comprises the steps that a disturbance instruction is sent to a target power grid, impedance information of the target power grid is determined according to change values of operation parameters of the target power grid, and the disturbance instruction comprises an active step change value and / or a reactive step change value; a first switching frequency of an inverter is calculated based on the impedance information and a preset power grid reactive power value, and the inverter is electrically connected with the target power grid; and under the condition that the first switching frequency accords with the operation condition of the inverter, determining to control a switch of the inverter to execute on-off processing according to the first switching frequency. The method is used for achieving the effect of controlling the switching frequency of the inverter based on the reactive power of the power grid.

Description

Technical Field

[0001] This application relates to the field of power supply, and more particularly to a grid-based inverter control method, electronic equipment, storage medium, and program product. Background Technology

[0002] In new energy power generation systems (such as photovoltaic and wind power), the inverter, as the core device for converting DC power to AC power, directly affects the power quality, efficiency, and stability of the system through its filtering design. Traditionally, LCL-type filters are designed and optimized based on typical operating conditions with rated maximum power and a fixed power factor.

[0003] While this design approach can guarantee that performance indicators meet the nominal operating conditions, it faces significant limitations in practical applications: it takes the ideal scenario of "full load + high power factor" as the benchmark and ignores the intermittent, fluctuating and uncertain characteristics unique to renewable energy.

[0004] Currently, there is an urgent need for a solution to control the inverter switching frequency based on the reactive power of the power grid. Summary of the Invention

[0005] This application provides a grid-based inverter control method, electronic device, storage medium, and program product to achieve the effect of controlling the inverter switching frequency based on the reactive power of the grid.

[0006] In a first aspect, embodiments of this application provide a grid-based inverter control method, comprising: issuing a disturbance command to a target grid; determining the impedance information of the target grid based on changes in the operating parameters of the target grid, wherein the disturbance command includes: an active power step change value and / or a reactive power step change value; calculating a first switching frequency of the inverter based on the impedance information and a preset grid reactive power value, wherein the inverter is electrically connected to the target grid; and determining, when the first switching frequency meets the operating conditions of the inverter, to control the inverter to perform on / off processing according to the first switching frequency.

[0007] In one possible implementation, the current amplitude corresponding to the preset grid reactive power value is determined; a target current ripple range is obtained by calculation based on the current amplitude and the preset current ripple range; and the first switching frequency of the inverter is determined based on the target current ripple range and impedance information.

[0008] In one possible implementation, the target voltage value corresponding to the filter inductor in the inverter is determined based on the operating parameters of the target power grid; the first switching frequency of the inverter is determined based on the target current ripple range of the target voltage value and the inductance information carried in the impedance information.

[0009] In one possible implementation, if the disturbance command includes an active power step change value, the reactive power of the target power grid is kept constant, and a first current change value and a first voltage change value of the target power grid are obtained; the resistance information of the target power grid is determined based on the first current change value and the first voltage change value; if the disturbance command includes a reactive power step change value, the active power of the target power grid is kept constant, and a second current change value and a second voltage change value of the target power grid are obtained; the inductance information of the target power grid is determined based on the second current change value and the second voltage change value; and the impedance information of the target power grid is determined based on the resistance information and the inductance information.

[0010] In one possible implementation, when the inverter switches at the first switching frequency, a first voltage value of the inverter connected to the target power grid is obtained; the first voltage value is compared with a preset voltage threshold for the target power grid operation; if the first voltage value is greater than the preset voltage threshold, the target reactive power is calculated based on the rated voltage of the target power grid.

[0011] In one possible implementation, if the first switching frequency does not meet the operating conditions of the inverter, the maximum switching frequency value carried by the operating conditions is determined; the maximum switching frequency value is determined as the new first switching frequency; and the switch controlling the inverter is determined to operate according to the new first switching frequency.

[0012] Secondly, embodiments of this application provide a grid-based inverter control device, comprising: a determination module, configured to issue a disturbance command to a target grid and determine the impedance information of the target grid based on changes in the operating parameters of the target grid, wherein the disturbance command includes: an active power step change value and / or a reactive power step change value; a calculation module, configured to calculate a first switching frequency of the inverter based on the impedance information and a preset grid reactive power value, wherein the inverter is electrically connected to the target grid; and a control module, configured to determine, when the first switching frequency meets the operating conditions of the inverter, to control the inverter to perform on / off processing according to the first switching frequency.

[0013] Thirdly, embodiments of this application provide a grid-based inverter control device, including: a memory and a processor;

[0014] The memory stores computer-executed instructions;

[0015] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0016] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0017] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0018] The grid-based inverter control method, electronic device, storage medium, and program product provided in this application embodiment apply controllable power surges and observe the grid's response characteristics to them, thereby deriving the current equivalent impedance parameters of the target grid. Based on the impedance value obtained in the previous step (reflecting the grid's rigidity) and a pre-set reactive power target value, a target switching frequency suitable for the current operating conditions is calculated. Only when the target switching frequency meets the inverter's operating conditions is a PWM waveform with the corresponding duty cycle sent to the inverter's drive circuit, causing the power semiconductor devices to periodically turn on and off according to the target switching frequency, achieving the effect of controlling the inverter's switching frequency based on the magnitude of the grid's reactive power. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0020] Figure 1 The schematic diagram of the grid-based inverter control provided in this application Figure 1 ;

[0021] Figure 2 A flowchart illustrating the grid-based inverter control method provided in this application. Figure 2 ;

[0022] Figure 3 A schematic diagram of the structure of the grid-based inverter control device provided in this application;

[0023] Figure 4 A schematic diagram of the structure of the grid-based inverter control device provided in this application.

[0024] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0026] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0027] Figure 1 The schematic diagram of the grid-based inverter control provided in this application Figure 1 ,like Figure 1 As shown, the method includes:

[0028] S201. Send a disturbance command to the target power grid and determine the impedance information of the target power grid based on the changes in the operating parameters of the target power grid.

[0029] The disturbance command includes: active step change value and / or reactive step change value.

[0030] For example, a specific step change in active / reactive power (such as increasing or decreasing a certain amount of P or Q) is injected into the target power grid, and then the resulting changes in operating parameters such as voltage and current are monitored. ).

[0031] The comprehensive impedance value of the power grid is derived using the dynamic response relationship of Ohm's law. ).For example:

[0032] If only the active power is changed ( ), which can mainly reflect the resistance component (R);

[0033] If only reactive power is changed ( If ), then the focus is on the reactance component (X).

[0034] Alternatively, assuming that the grid impedance remains constant before and after the disturbance, the above results can be used to construct the initial impedance model. The estimated The data is stored in the DSP as the basis for subsequent control.

[0035] Traditional methods rely on offline measurements or empirical models, while this real-time online identification can more accurately capture the actual electrical characteristics of the current power grid, and is especially suitable for complex and ever-changing new energy grid connection scenarios.

[0036] S202. Calculate the first switching frequency of the inverter based on the impedance information and the preset reactive power value of the power grid, wherein the inverter is electrically connected to the target power grid; substitute the impedance parameters obtained in the previous step into the preset algorithm formula to calculate the target switching frequency that makes the inverter operate in the optimal state. This frequency must simultaneously satisfy two constraints:

[0037] Resonance avoidance: Avoiding the inherent resonant point of the LC filter to prevent oscillations caused by impedance mismatch;

[0038] Loss balancing: weighing switching losses against conduction losses, and selecting the frequency band with the highest efficiency.

[0039] Compared to fixed-frequency designs, dynamically adaptable switching frequencies significantly improve the system's adaptability under different operating conditions. For example:

[0040] Automatically reduces frequency to minimize impact when operating on a weak power grid (high impedance);

[0041] Increasing the frequency improves waveform quality when using a strong power grid (low impedance).

[0042] S203. If the first switching frequency meets the operating conditions of the inverter, determine that the switch of the inverter is controlled to perform on / off processing according to the first switching frequency.

[0043] Optionally, the operating conditions may include:

[0044] Hardware boundary check: Confirmed The maximum permissible switching frequency of power devices such as IGBTs shall not exceed the maximum allowable switching frequency.

[0045] Thermal stability assessment: whether the junction temperature rise under simulated long-term operation is within a reasonable range.

[0046] The controller will only issue a command to the inverter to operate when all conditions are met. Run; otherwise, initiate a rollback mechanism to recalculate the available reactive power output range based on the maximum permissible frequency (similar to a "derating for safety" mode). This conservative strategy effectively avoids the risk of equipment damage caused by parameter drift.

[0047] In the design process of inverter LCL filters, most filters are designed according to the operating condition of the maximum output current value that can output the maximum power factor. For example, in the design process of a 100kW inverter, if the specified power factor is 0.8, then the inverter needs to be able to operate under the condition of 100kW and power factor 0.8.

[0048] However, in practical applications, inverters are constrained by the constantly changing input energy levels from photovoltaic panels and wind power. In addition to the limitations of the power factor, more and more scenarios now require the use of even lower power factors, or even a state of generating pure reactive power.

[0049] The grid-based inverter control method provided in this application applies a method that artificially applies controllable power surges and observes the grid's response characteristics to these surges. This allows for the derivation of the target grid's current equivalent impedance parameters. Based on the impedance value obtained in the previous step (reflecting the grid's rigidity) and a pre-set reactive power target value, a target switching frequency suitable for the current operating conditions is calculated. Only when the target switching frequency meets the inverter's operating conditions is a PWM waveform with the corresponding duty cycle sent to the inverter's drive circuit. This causes the power semiconductor devices to periodically turn on and off according to the target switching frequency, achieving the effect of controlling the inverter's switching frequency based on the grid's reactive power level.

[0050] Figure 2 A flowchart illustrating the grid-based inverter control method provided in this application. Figure 2 ,like Figure 2 As shown, in this embodiment... Figure 1 Based on the embodiments, a grid-based inverter control method is described in detail, which includes:

[0051] S301. When the disturbance command includes an active power step change value, keep the reactive power of the target power grid constant, and obtain the first current change value and the first voltage change value of the target power grid; determine the resistance information of the target power grid based on the first current change value and the first voltage change value; when the disturbance command includes a reactive power step change value, keep the active power of the target power grid constant, and obtain the second current change value and the second voltage change value of the target power grid; determine the inductance information of the target power grid based on the second current change value and the second voltage change value; determine the impedance information of the target power grid based on the resistance information and the inductance information.

[0052] This method utilizes the dynamic form of Ohm's law (considering the phase difference under inductive loads). By controlling the inverter to inject a known amount of active or reactive step change into the grid, and observing the resulting voltage and current responses, the equivalent impedance model of the grid can be derived.

[0053] "Keep the reactive power of the target power grid constant" (i.e.) ); change the active power output (e.g., increase) Record the sudden change in current at this time. and voltage fluctuations In a purely resistive system, voltage and current are in phase and satisfy... Since the reactive power remains unchanged at this time (capacitive reactance is not activated), the measured change mainly reflects the resistance characteristics.

[0054] Keep the active power of the target power grid constant (i.e.) );

[0055] Sudden change in reactive power output (such as increasing) Record the sudden change in current at this time. and voltage fluctuations .

[0056] In a purely inductive system, voltage leads current. And satisfy (ω is the angular frequency). At this point, the active power is locked, and only the inductive characteristics of the power grid are activated.

[0057] In other words, by controlling a single variable (changing only the active or reactive power) while keeping the other power constant, decoupled observation of the resistive and inductive components can be achieved.

[0058] S302. Determine the current amplitude corresponding to the preset reactive power value of the power grid; calculate the target current ripple range based on the current amplitude and the preset current ripple range; determine the first switching frequency of the inverter based on the target current ripple range and impedance information.

[0059] It should be noted that there is an upper limit to the ripple current value required by the system, such as... If it is desired that the inverter will generate more reactive power, the switching frequency needs to be increased accordingly to reduce harmonics.

[0060] According to the basic formula of AC circuit (Reactive power = effective voltage value × reactive current component), transforming the abstract reactive power command into a specific current dimension.

[0061] For example, the target voltage value corresponding to the filter inductor in the inverter is determined based on the operating parameters of the target power grid; the first switching frequency of the inverter is determined based on the target voltage value, the target current ripple range, and the inductance information carried in the impedance information.

[0062] For inductors, their inductance changes due to their DC bias characteristics. Here, I represents the current value, N is the number of turns in the inductor wire, Le is the length of the magnetic circuit, and the magnetic field H of the inductor changes, thus affecting the inductance value.

[0063]

[0064] As the inverter power factor decreases, the inverter circuit is equivalent to a BUCK circuit, and the inverter output harmonics are as shown in Equation 2:

[0065] (2)

[0066] Wherein, ∆I: the allowable peak current ripple, which is usually determined by u% * I_rated (rated current).

[0067] |V1|: The amplitude of the fundamental component of the inverter output voltage (approximate to the amplitude of the grid voltage).

[0068] |Vbus|: DC bus voltage of the inverter.

[0069] Fsw: The switching frequency that needs to be solved.

[0070] La1: Filter inductance value.

[0071] u%: Percentage of allowable current ripple relative to rated current.

[0072] Convert the target reactive power Q_target into a current command to determine the required ∆I (i.e., u% * I_target). Then substitute parameters such as La1, V1, and Vbus into the formula.

[0073] Inverse calculation of f_sw_req: Transform equation (2) into f_sw_req = (|V1| * (1 - |V1| / |Vbus|)) / (∆I * La1), and the required switching frequency can be calculated.

[0074] Furthermore, if f_sw_req <= f_sw_max, it means that the inverter can safely output the target reactive power, using Q_target (target reactive power value).

[0075] If f_sw_req > f_sw_max: This indicates that outputting reactive power will cause the switching frequency to exceed the limit, damaging the device.

[0076] Inverse calculation of Q_max: Because changes in Q affect I_target and ∆I, thus affecting the formula. The strategy is to substitute f_sw_max into the formula, deduce the maximum allowable ∆I under the current conditions, and then deduce the maximum allowable output current based on ∆I, finally obtaining the maximum reactive power Q_max allowed by the inverter's own capabilities.

[0077] Issue the instruction: Change the final reactive power instruction from Q_target (reactive power target value) to Q_max.

[0078] S303. When the inverter switches at the first switching frequency, obtain the first voltage value of the inverter connected to the target power grid; compare the first voltage value with the preset voltage threshold of the target power grid; if the first voltage value is greater than the preset voltage threshold, calculate the target reactive power based on the rated voltage of the target power grid.

[0079] If the number of load nodes in the power grid is n, and a photovoltaic inverter is connected at the k-th node, the voltage at inverter connection point k is denoted by Uk. The active and reactive power of this power source are denoted by PDG,k and QDG,k, respectively. The equivalent resistance and reactance of the i-th line segment are denoted by Ri and Xi, and the load power is denoted by PLi+jQLi. After the photovoltaic grid connection, the voltage drop at power source connection point k is denoted by Uk, and the formula for calculating Uk is:

[0080] (3)

[0081] Uk: The voltage of the kth node (referring to the voltage of the inverter grid connection point PCC).

[0082] Un: Rated voltage of the power grid source.

[0083] PDG,k, QDG,k: Active and reactive power flowing into the k-th node (i.e., the power output by the inverter).

[0084] ∑Rj, ∑Xj: Total resistance and total reactance along the path from the source of the power grid to the kth node (i.e., R and X estimated in the first stage).

[0085] If |ΔU| <= U_critical value: the instruction is safe and can be executed.

[0086] If |ΔU| > U_critical value, it will cause the grid voltage to exceed the limit.

[0087] Inverse calculation of Q_safety value: Let ΔU = U_critical value, substitute into the formula U_critical value = (Q_safety value * X) / Un, and directly solve for Q_safety value = (U_critical value * Un) / X.

[0088] Issue the instruction: Change the final reactive power instruction to the Q_safety value.

[0089] S304. If the first switching frequency does not meet the operating conditions of the inverter, determine the maximum switching frequency value carried by the operating conditions; determine the maximum switching frequency value as the new first switching frequency; and determine that the switch controlling the inverter operates according to the new first switching frequency.

[0090] It should be noted that the initially calculated theoretical switching frequency (the "first switching frequency" derived from formulas based on current ripple, impedance matching, etc.) may exceed the limitations of the hardware or design. For example:

[0091] Exceeding the maximum permissible switching frequency (limited by IGBT / MOSFET switching speed and drive circuit bandwidth);

[0092] This results in excessively high switching losses (affecting efficiency and heat dissipation).

[0093] This can cause electromagnetic interference (EMI) to exceed the standard.

[0094] There is a risk of coupling oscillation with other components of the system.

[0095] The DSP / MCU determines whether the limit has been exceeded by comparing the actual calculated value with the preset protection threshold (such as f_max, thermal model warning line).

[0096] The grid-based inverter control method, electronic device, storage medium, and program product provided in this application embodiment apply controllable power surges and observe the grid's response characteristics to them, thereby deriving the current equivalent impedance parameters of the target grid. Based on the impedance value obtained in the previous step (reflecting the grid's rigidity) and a pre-set reactive power target value, a target switching frequency suitable for the current operating conditions is calculated. Only when the target switching frequency meets the inverter's operating conditions is a PWM waveform with the corresponding duty cycle sent to the inverter's drive circuit, causing the power semiconductor devices to periodically turn on and off according to the target switching frequency, achieving the effect of controlling the inverter's switching frequency based on the magnitude of the grid's reactive power.

[0097] Figure 3 A schematic diagram of the structure of the grid-based inverter control device provided in this application is shown below. Figure 3 As shown, the grid-based inverter control device 40 provided in this embodiment includes:

[0098] The determination module 401 is used to send a disturbance command to the target power grid and determine the impedance information of the target power grid based on the change value of the operating parameters of the target power grid. The disturbance command includes: active step change value and / or reactive step change value.

[0099] Calculation module 402 is used to calculate the first switching frequency of the inverter based on impedance information and preset grid reactive power value, wherein the inverter is electrically connected to the target grid.

[0100] The control module 403 is used to determine, when the first switching frequency meets the operating conditions of the inverter, to control the inverter to perform on / off processing according to the first switching frequency.

[0101] In one possible implementation, the calculation module 402 is used to determine the current amplitude corresponding to the preset grid reactive power value; calculate the target current ripple range based on the current amplitude and the preset current ripple range; and determine the first switching frequency of the inverter based on the target current ripple range and impedance information.

[0102] In one possible implementation, the calculation module 402 is used to determine the target voltage value corresponding to the filter inductor in the inverter based on the operating parameters of the target power grid; and to determine the first switching frequency of the inverter based on the target voltage value, the target current ripple range, and the inductance information carried in the impedance information.

[0103] In one possible implementation, the determining module 401 is configured to, when the disturbance command includes an active power step change value, keep the reactive power of the target power grid constant, acquire a first current change value and a first voltage change value of the target power grid; determine the resistance information of the target power grid based on the first current change value and the first voltage change value; when the disturbance command includes a reactive power step change value, keep the active power of the target power grid constant, acquire a second current change value and a second voltage change value of the target power grid; determine the inductance information of the target power grid based on the second current change value and the second voltage change value; and determine the impedance information of the target power grid based on the resistance information and the inductance information.

[0104] In one possible implementation, the control module 403 is used to obtain a first voltage value of the inverter connected to the target power grid when the inverter switches at a first switching frequency; compare the first voltage value with a preset voltage threshold for the target power grid operation; and if the first voltage value is greater than the preset voltage threshold, calculate the target reactive power based on the rated voltage of the target power grid.

[0105] In one possible implementation, the control module 403 is used to determine the maximum switching frequency value carried by the operating conditions when the first switching frequency does not meet the operating conditions of the inverter; determine the maximum switching frequency value as the new first switching frequency; and determine to control the inverter to operate according to the new first switching frequency.

[0106] The grid-based inverter control device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0107] Figure 4 This is a schematic diagram of the structure of the grid-based inverter control device provided in this application. Figure 4As shown, the electronic device 50 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the device 50 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus 504.

[0108] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0109] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0110] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0111] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0112] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0113] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0114] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0115] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0116] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0117] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0118] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0119] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0120] If a function is implemented as 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 this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0121] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0122] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A grid-based inverter control method, characterized in that, include: A disturbance command is sent to the target power grid, and the impedance information of the target power grid is determined based on the change values ​​of the operating parameters of the target power grid. The disturbance command includes: active step change value and / or reactive step change value. The first switching frequency of the inverter is calculated based on the impedance information and the preset reactive power value of the power grid, wherein the inverter is electrically connected to the target power grid. If the first switching frequency meets the operating conditions of the inverter, it is determined that the switch controlling the inverter will perform on / off processing according to the first switching frequency.

2. The method according to claim 1, characterized in that, The first switching frequency of the inverter is calculated based on the impedance information and the preset reactive power value of the power grid, including: Determine the current amplitude corresponding to the preset reactive power value of the power grid; The target current ripple range is obtained by calculating based on the current amplitude and the preset current ripple range. The first switching frequency of the inverter is determined based on the target current ripple range and impedance information.

3. The method according to claim 2, characterized in that, Determining the first switching frequency of the inverter based on the target current ripple range and impedance information includes: The target voltage value corresponding to the filter inductor in the inverter is determined based on the operating parameters of the target power grid. The first switching frequency of the inverter is determined based on the target voltage value, the target current ripple range, and the inductance information carried in the impedance information.

4. The method according to claim 1, characterized in that, Sending a disturbance command to the target power grid and determining the impedance information of the target power grid based on the changes in the operating parameters of the target power grid, including: When the disturbance command includes an active step change value, the reactive power of the target power grid is kept constant, and the first current change value and the first voltage change value of the target power grid are obtained. The resistance information of the target power grid is determined based on the first current change value and the first voltage change value; When the disturbance command includes a reactive step change value, the active power of the target power grid is kept constant, and the second current change value and the second voltage change value of the target power grid are obtained. The inductance information of the target power grid is determined based on the second current change value and the second voltage change value; The impedance information of the target power grid is determined based on the resistance information and the inductance information.

5. The method according to claim 1, characterized in that, After determining that the switch controlling the inverter performs on / off processing according to the first switching frequency, the method further includes: When the inverter switches at the first switching frequency, the first voltage value of the inverter connected to the target power grid is obtained; The first voltage value is compared with a preset voltage threshold for the target power grid. If the first voltage value is greater than the preset voltage threshold, the target reactive power is calculated based on the rated voltage of the target power grid.

6. The method according to claim 1, characterized in that, Before determining that the switch controlling the inverter performs on / off processing according to the first switching frequency, the method further includes: If the first switching frequency does not meet the operating conditions of the inverter, determine the maximum switching frequency value carried by the operating conditions; The maximum frequency value of the switch is determined as the new first switching frequency; The switch controlling the inverter is determined to operate at a new first switching frequency.

7. A grid-based inverter control device, characterized in that, include: The determination module is used to issue a disturbance command to the target power grid and determine the impedance information of the target power grid based on the change value of the operating parameters of the target power grid. The disturbance command includes: active step change value and / or reactive step change value. The calculation module is used to calculate the first switching frequency of the inverter based on the impedance information and the preset reactive power value of the power grid, wherein the inverter is electrically connected to the target power grid; The control module is used to determine, when the first switching frequency meets the operating conditions of the inverter, to control the switch of the inverter to perform on / off processing according to the first switching frequency.

8. A grid-based inverter control device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-6.

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