Current DC component suppression method, inverter and photovoltaic energy storage system

Abstract

The present application provides a method for suppressing a DC component of a current, an inverter, and a photovoltaic energy storage system. The method for suppressing a DC component of a current is applied to an inverter circuit, the inverter circuit includes an AC interface, and the method includes: obtaining an interface current, a given DC component, and a preset reset current of the AC interface; obtaining an actual DC component of the current according to the interface current; determining a target reset current according to the actual DC component of the current, a given DC component, and a preset reset current; and adjusting the interface current according to the target reset current. The method for suppressing a DC component of a current provided in the present application can achieve effective control of the DC component of the current on the inverter circuit.

Description

Technical Field

[0001] The present application relates to the field of electronic power technology, and in particular to a method for suppressing a DC component of a current, an inverter, and a photovoltaic energy storage system. Background Art

[0002] In the related art, the switch tube of the inverter circuit in the inverter (such as a micro inverter) can adopt a critical current mode control method to reset the switch tube cycle when the interface current of the inverter's AC interface is regulated to the corresponding reset current. However, due to the Hall characteristics, the sampling of the interface current may be delayed. In this way, the actual upper and lower limits of the interface current and the theoretical upper and lower limits of the current may be offset, resulting in asymmetry of the actual positive and negative half-cycles of the interface current. Moreover, it is difficult to accurately control the interface current when the switch tube is reset in the related art. The above reasons make it easy for the DC component of the interface current to exceed the standard, thereby affecting the safe operation of the inverter circuit and the system connected to it, such as affecting the safe operation of the inverter circuit when it is connected to the power grid. However, the traditional control method of the DC component of the current has limited effect in the control method of the critical current mode. Therefore, a method for suppressing the DC component of the current is urgently needed to achieve effective control of the DC component of the current. Summary of the invention

[0003] In view of this, the present application provides a current DC component suppression method, an inverter and a photovoltaic energy storage system to achieve effective control of the DC component of the current on the inverter circuit.

[0004] The present application provides a first aspect of a current DC component suppression method, which is applied to an inverter circuit. The inverter circuit includes an AC interface. The method includes: obtaining an interface current, a given DC component, and a preset reset current of the AC interface; obtaining an actual current DC component according to the interface current; determining a target reset current according to the actual current DC component, the given DC component, and the preset reset current; and adjusting the interface current according to the target reset current.

[0005] In one embodiment, before determining the target reset current based on the actual current DC component, the given DC component and the preset reset current, the method also includes: determining an adjustment current value based on the actual current DC component and the given DC component; when the absolute value of the adjustment current value is greater than or equal to a preset threshold, executing the step of determining the target reset current based on the actual current DC component, the given DC component and the preset reset current.

[0006] In one embodiment, determining the target reset current according to the actual current DC component, the given DC component and the preset reset current includes: determining a compensation current value according to the actual current DC component and the given DC component; and determining the target reset current according to the compensation current value and the preset reset current.

[0007] In one embodiment, the preset reset current includes a first preset reset current and a second preset reset current, the target reset current includes a first target reset current and a second target reset current, the first preset reset current and the first target reset current are both less than 0, and the second preset reset current and the second target reset current are both greater than 0, and the target reset current is determined according to the compensation current value and the preset reset current, including: when the compensation current value is greater than 0, the first preset reset current minus the compensation current value is used as the first target reset current, and the second preset reset current minus the compensation current value is used as the second target reset current; when the compensation current value is less than 0, the first preset reset current plus the compensation current value is used as the first target reset current, and the second preset reset current plus the compensation current value is used as the second target reset current.

[0008] In one embodiment, determining the compensation current value according to the actual current DC component and the given DC component includes: taking the difference between the actual current DC component and the given DC component as the compensation current value.

[0009] In one embodiment, determining the adjusted current value according to the actual current DC component and the given DC component includes: obtaining a current deviation value between the actual current DC component and the given DC component; and performing deviation adjustment on the current deviation value to obtain the adjusted current value.

[0010] In one embodiment, after determining the adjustment current value according to the actual current DC component and the given DC component, the method further includes: when the absolute value of the adjustment current value is less than a preset threshold, adjusting the interface current according to the adjustment current value.

[0011] In one embodiment, before determining the target reset current based on the actual current DC component, the given DC component and the preset reset current, the method also includes: comparing the actual current DC component with the given DC component; when the actual current DC component is equal to the given DC component, returning to the step of obtaining the interface current of the AC interface, the given DC component and the preset reset current.

[0012] The second aspect of the present application provides an inverter, including an inverter circuit and a controller. The inverter circuit includes an AC interface, and the controller is used to: obtain an interface current and a preset reset current of the AC interface; obtain an actual current DC component according to the interface current; determine a target reset current according to the actual current DC component and the preset reset current; and adjust the interface current according to the target reset current.

[0013] The third aspect of the present application provides a photovoltaic energy storage system, comprising a power supply and the inverter described above. The inverter comprises a DC interface, the power supply is connected to the DC interface, and the power supply comprises a photovoltaic module and / or a battery.

[0014] The current DC component suppression method provided in the present application first obtains the actual current DC component according to the interface current, and then adjusts the preset reset current according to the deviation between the actual current DC component and the given DC component to determine the target reset current, and then adjusts the interface current according to the target reset current to adjust the actual current upper and lower limits of the interface current, thereby suppressing the current DC component in the interface current. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. In each of the drawings, similar components are numbered similarly.

[0016] Figure 1 The figure is a circuit diagram of an inverter circuit according to an embodiment of the present application.

[0017] Figure 2 for Figure 1 Schematic diagram of the waveform of the interface current of the AC interface.

[0018] Figure 3 A schematic flow chart of a method for suppressing a DC component of a current provided in one embodiment of the present application.

[0019] Figure 4 A schematic flow chart of a method for suppressing a DC component of a current provided in another embodiment of the present application.

[0020] Figure 5 A schematic diagram of sub-steps for determining a target reset current provided in an embodiment of the present application.

[0021] Figure 6 A schematic diagram of sub-steps of step S403 provided in an embodiment of the present application.

[0022] Figure 7 A structural block diagram of an inverter provided in one embodiment of the present application.

[0023] Figure 8 A structural block diagram of a photovoltaic energy storage system provided in one embodiment of the present application.

[0024] Fig. 9 This is a structural block diagram of a control device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0026] It is understandable that the connection relationship described in this application refers to direct or indirect connection. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components. For example, A and C can be directly connected, and C and B can be directly connected, so that A and B are connected through C. It is also understandable that the "A connects B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0027] In the description of this application, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this article is only a way to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0028] In the description of this application, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0030] Some embodiments will be described below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0031] See also Figure 1 , Figure 1 A circuit diagram of an inverter circuit 10 to which the control method for the DC component of the current of the inverter circuit provided by the present application is applied. It is understandable that the present application does not limit the type of inverter circuit to which the control method for the DC component of the current is applied. The present application only takes the inverter circuit 10 as a single-phase full-bridge inverter circuit as an example to illustrate the control method. In other embodiments, the inverter circuit 10 may also be a half-bridge inverter circuit, a bidirectional inverter circuit, etc., and the inverter circuit may also be a multi-phase inverter circuit.

[0032] Specifically, Figure 1The inverter circuit 10 shown includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a capacitor C1, an inductor L1, a DC interface (including a positive DC interface DC+ and a negative DC interface DC-) and an AC interface (including a positive AC interface AC+ and a negative AC interface AC-). Among them, the first end of the switch tube Q1 and the first end of the switch tube Q3 are both used to connect the positive DC interface DC+. The second end of the switch tube Q1 is electrically connected to the first end of the switch tube Q2. The second end of the switch tube Q3 is electrically connected to the first end of the switch tube Q4. The second end of the switch tube Q2 and the second end of the switch tube Q4 are both used to connect the negative DC interface DC-. The first end of the inductor L1 is electrically connected between the second end of the switch tube Q1 and the first end of the switch tube Q2, and the second end of the inductor L1 is electrically connected to the positive AC interface AC+. The negative AC interface AC- of the inverter circuit 10 is electrically connected between the second end of the switch tube Q3 and the first end of the switch tube Q4. The capacitor C1 is connected between the positive AC interface AC+ and the negative AC interface AC- of the inverter circuit 10. The controlled ends of the switch tubes Q1, Q2, Q3 and Q4 are all electrically connected to a controller (not shown). The controller can output corresponding control signals to the switch tubes Q1-Q4, and the control signals are used to control the on and off of the switch tubes Q1-Q4.

[0033] In the related art, the switch tube of the inverter circuit in the inverter (such as a micro inverter) can adopt a critical current mode control method to periodically reset when the upper and lower limits of the interface current of the AC interface of the inverter circuit reach the corresponding reset current.

[0034] For example, see Figure 2 , Figure 2 The interface current I of the inverter circuit 10 is shown as L The current waveform diagram of the inverter circuit 10 is shown in FIG. 1 . The reset current set in the inverter circuit 10 includes Ib+ and Ib-. An interface current I L The complete cycle of includes the first cycle and the second cycle, and the interface current I L The average current value may be greater than 0, for example, and the interface current I L The average current value may be less than 0, for example. L When the average current value is greater than 0, the interface current I L The current lower limit is maintained at the reset current Ib-. When the interface current I L When the current lower limit exceeds the reset current Ib-, the controller confirms to enter the second cycle; when the interface current I L When the average current value is less than 0, the interface current I L The current upper limit is maintained at the reset current Ib+. When the interface current I LWhen the current upper limit exceeds the reset current Ib+, the controller confirms that it has entered the first cycle. L The current value is compared with the reset current Ib- and reset current Ib+ to realize the interface current I L The periodic reset between the first cycle and the second cycle. It is understandable that in other embodiments, the interface current I L The average current value is less than 0 and the interface current I L The average current is greater than 0.

[0035] However, due to the limitation of Hall characteristics, the interface current I L There is a delay in sampling, so the interface current I L The actual current upper and lower limits and the theoretical current upper and lower limits (i.e., reset current Ib- and reset current Ib+) may be offset, resulting in asymmetry of the actual positive and negative half-cycles of the interface current. Moreover, it is difficult to accurately control the interface current when the switch tube is reset in the related technology. The above reasons make the interface current I L The DC component of the current is easily exceeded, thereby affecting the safe operation of the inverter circuit and the system connected thereto, such as affecting the safe operation of the inverter circuit 10 when it is connected to the power grid. The control method of the DC component of the current in the related art has limited effect in the control method of the critical current mode. Therefore, a method for suppressing the DC component of the current is urgently needed to achieve effective control of the DC component of the current.

[0036] In view of this, the present application provides a current DC component suppression method, an inverter and a photovoltaic energy storage system to achieve effective control of the DC component of the current at the AC interface of the inverter circuit.

[0037] Please continue reading Figure 3 , Figure 3 A flow chart of a method for controlling a DC component of a current provided in an embodiment of the present application. It is understandable that the control method can be executed by a controller of an inverter circuit. The method includes:

[0038] Step S301: obtaining an interface current of an AC interface, a given DC component, and a preset reset current.

[0039] Please also refer to Figure 1 , the interface current may be the current flowing through the inductor L1.

[0040] The given DC component is used to represent the ideal value of the DC component of the interface current. The given DC component can be a positive number, a negative number or 0. The present application does not limit the value of the given DC component.

[0041] The preset reset current can be used to adjust the interface current so that the interface current can be reset periodically. The given DC component and the preset reset current can be preset values.

[0042] Step S302: obtaining the actual current DC component according to the interface current.

[0043] In some embodiments, the current of the interface current in a complete cycle (including the first cycle and the second cycle) can be sampled by a sampling circuit, and the current sampled in a complete cycle is integrated to calculate an average value, so that the average value is used as the actual current DC component of the interface current. This application does not limit the specific algorithm or specific circuit structure used to obtain the actual current DC component of the interface current. In other embodiments, step S2 can also use other methods to obtain the actual current DC component according to the interface current.

[0044] Step S303: determining a target reset current according to the actual current DC component, the given DC component and the preset reset current.

[0045] It is understandable that the deviation between the actual current DC component and the given DC component should be within a smaller preset range. When the deviation between the actual current DC component and the given DC component exceeds the preset range, the interface current should be adjusted to reduce the DC component of the interface current. Since the reset current can be used to limit the upper and lower limits of the interface current within a certain range, in step S303, the preset reset current can be adjusted according to the deviation between the actual current DC component and the given DC component to determine the target reset current, thereby controlling the upper and lower current limits of the interface current according to the target reset current to suppress the DC component of the interface current.

[0046] For example, if the actual current DC component is greater than the given DC component, the interface current I L The average current of the first half cycle is greater than the average current of the second half cycle. Since the reset current Ib- is less than 0 and the average current of the first cycle corresponding to the reset current Ib- is greater than 0, the reset current Ib- can be adjusted down to reduce the interface current I L At the same time, since the reset current Ib+ is greater than 0 and the current average value of the second cycle corresponding to the reset current Ib+ is less than 0, the reset current Ib+ can be adjusted down to further reduce the interface current I L The average current value in the second cycle. In this way, by synchronously reducing the reset current Ib- and the reset current Ib+, the interface current I L The lower limit value of the first cycle and the interface current I L The upper limit of the second cycle quickly reduces the interface current I LThe average current value in the first half cycle is used to suppress the DC component of the interface current in the first half cycle. The lowered reset current Ib+ and the lowered reset current Ib- are the target reset currents.

[0047] Similarly, if the actual current DC component is less than the given DC component, the average current value of the first half cycle of the interface current is less than the average current value of the second half cycle. Since the reset current Ib- is less than 0 and the average current value of the first cycle corresponding to the reset current Ib- is greater than 0, the reset current Ib- can be adjusted upward to increase the average current value of the interface current in the first cycle. At the same time, since the reset current Ib+ is greater than 0 and the average current value of the second cycle corresponding to the reset current Ib+ is less than 0, the reset current Ib+ can be adjusted upward to further increase the interface current I L The average current value in the second cycle. In this way, by synchronously increasing the reset current Ib- and the reset current Ib+, the interface current I L The lower limit value of the first cycle and the interface current I L The upper limit of the second cycle, thereby quickly increasing the interface current I L The average current value in the first half cycle is used to suppress the DC component of the interface current in the second half cycle. The increased reset current Ib+ and the increased reset current Ib- are the target reset currents.

[0048] Step S304: adjusting the interface current according to the target reset current.

[0049] In step S304 , the controller may output corresponding control signals to the switch tubes Q1 to Q4 to adjust the waveform of the interface current according to the target reset current, thereby adjusting the DC component of the interface current.

[0050] In summary, the current DC component suppression method provided in the present application first obtains the actual current DC component based on the interface current, and then adjusts the preset reset current according to the deviation between the actual current DC component and the given DC component to determine the target reset current, and then adjusts the interface current according to the target reset current to adjust the actual current upper and lower limits of the interface current, thereby suppressing the current DC component in the interface current.

[0051] Understandably, Figure 2 The current waveform shown is a schematic diagram of the current waveform when the interface current is in a constant reset current mode in one embodiment of the present application. The current DC component suppression method provided in the present application can also be applied to other reset current modes, such as a constant current variation mode, a variable reset current mode, etc.

[0052] See also Figure 4 , Figure 4A schematic flow chart of a method for suppressing a DC component of a current provided in another embodiment of the present application. Figure 4 The current DC component suppression method shown includes the following steps:

[0053] Step S401: obtaining an interface current of an AC interface, a given DC component, and a preset reset current.

[0054] Step S402: obtaining the actual current DC component according to the interface current.

[0055] The specific execution process of step S401 and step S402 is substantially the same as that of step S301 and step S302 in the above text, and will not be repeated here.

[0056] Step S403: determining an adjusted current value according to the actual current DC component and the given DC component.

[0057] The adjusted current value indicates an adjustment amount of a given value of the interface current obtained based on a deviation between an actual current DC component and a given DC component. Understandably, when the DC component of the interface current exceeds the standard, the interface current may be adjusted directly by adjusting the current value (for example, by adjusting the current given value of the interface current, and then adjusting the interface current according to the adjusted current given value), thereby suppressing the DC component of the interface current.

[0058] In some embodiments, the actual current DC component can be used as the feedback value, the given DC component can be used as the given value, and the regulated current value can be calculated based on the deviation between the given value and the feedback value. This application does not limit the specific algorithm for calculating the regulated current value.

[0059] Step S404: when the absolute value of the adjusted current value is greater than or equal to the preset threshold, determining the target reset current according to the actual current DC component, the given DC component and the preset reset current.

[0060] The preset threshold value is used to indicate a threshold value of the regulated current value that causes the interface current to overshoot.

[0061] Understandably, in the process of controlling the DC component of the current, if the adjusted current value is too large or too small, the DC component of the current may be over-regulated. That is, when the absolute value of the adjusted current value is greater than or equal to the preset threshold, the method of controlling the DC component of the interface current according to the adjusted current value may fail. In this way, in step S404, when it is determined that the adjusted current value is greater than or equal to the preset threshold, the target reset current is determined based on the actual current DC component, the given DC component and the preset reset current.

[0062] Step S405: adjusting the interface current according to the target reset current.

[0063] It is understandable that step S405 is substantially the same as step S304 and will not be described in detail herein.

[0064] In this way, by executing step S401 to step S404 , the DC component of the interface current can be better suppressed.

[0065] Please refer again Figure 4 , in some embodiments, Figure 4 The method shown also includes:

[0066] Step S406: When the absolute value of the adjusted current value is less than the preset threshold, the interface current is adjusted according to the adjusted current value.

[0067] It can be understood that when the absolute value of the regulated current value is less than the preset threshold value, it indicates that the probability of the current regulated current value causing the interface current overshoot is low. Thus, when the given value of the interface current is adjusted according to the regulated current value, the actual DC component of the interface current can be made close to the given DC component in the next complete cycle, thereby achieving control over the DC component of the interface current.

[0068] Please continue reading Figure 5 In some embodiments, determining the target reset current according to the actual current DC component, the given DC component and the preset reset current includes the following sub-steps:

[0069] Step S501: determining a compensation current value according to an actual current DC component and a given DC component.

[0070] In some embodiments, a difference value obtained by subtracting a given DC component from an actual current DC component is used as the compensation current value.

[0071] In other embodiments, after obtaining the difference between the actual current DC component and the given DC component, the difference may be calculated based on a PI controller (Proportional Integral controller) or a PID controller (Proportion Integration Differentiation controller) to obtain a compensation current value. This application does not limit the calculation method for determining the compensation current value according to the actual current DC component and the given DC component in step S501.

[0072] Among them, when the compensation current value calculated in step S501 is greater than 0, it means that the average value of the interface current in the upper half cycle (i.e., the positive half cycle) is greater than the average value of the interface current in the lower half cycle (i.e., the negative half cycle); when the compensation current value is less than 0, it means that the average value of the interface current in the upper half cycle (i.e., the positive half cycle) is less than the average value of the interface current in the lower half cycle (i.e., the negative half cycle).

[0073] Step S502: determining a target reset current according to the compensation current value and the preset reset current.

[0074] In step S502 , the preset reset current may be adjusted upward or downward according to the compensation current value to obtain a target reset current.

[0075] In this way, by executing step S501 to step S502 , the target reset current can be determined according to the actual current DC component, the given DC component and the preset reset current.

[0076] In some embodiments, the preset reset current includes a first preset reset current and a second preset reset current, the target reset current includes a first target reset current and a second target reset current, and the first preset reset current and the first target reset current are both less than 0, and the second preset reset current and the second target reset current are both greater than 0. Thus, step S502 includes:

[0077] When the compensation current value is greater than 0, the first preset reset current minus the compensation current value is used as the first target reset current, and the second preset reset current minus the compensation current value is used as the second target reset current;

[0078] When the compensation current value is less than 0, the first preset reset current plus the compensation current value is used as the first target reset current, and the second preset reset current plus the compensation current value is used as the second target reset current.

[0079] In this way, the interface current is adjusted according to the first target reset current and the second target reset current, so that the actual current DC component of the interface current can be suppressed.

[0080] See also Figure 6 , in some embodiments, Figure 4 The illustrated step S403 includes the following sub-steps:

[0081] Step S601: obtaining a current deviation value between an actual current DC component and a given DC component.

[0082] In some embodiments, a difference value obtained by subtracting a given DC component from an actual current DC component is used as the current deviation value.

[0083] Step S602: performing deviation adjustment on the current deviation value to obtain an adjusted current value.

[0084] In some embodiments, the current deviation value is adjusted by performing deviation adjustment on the current deviation value, and the current deviation value can be calculated based on a PI controller (Proportional Integral controller) or a PID controller (Proportion Integration Differentiation controller) to obtain an adjusted current value. The present application does not limit the calculation method for performing deviation adjustment on the current deviation value to obtain an adjusted current value in step S602.

[0085] In some embodiments, before determining the target reset current according to the actual current DC component, the given DC component and the preset reset current, the method further includes:

[0086] Compare the actual current DC component with the given DC component;

[0087] When the actual current DC component is equal to the given DC component, the process returns to the step of obtaining the interface current of the AC interface, the given DC component and the preset reset current.

[0088] Understandably, when the actual DC component is equal to the given DC component, it indicates that the DC component of the current interface current does not need to be adjusted, and therefore the method can be returned to the step of obtaining the interface current of the AC interface, the given DC component and the preset reset current, and the above method can be re-executed.

[0089] See also Figure 7 The present application also provides an inverter 100. The inverter 100 includes an inverter circuit 10 and a controller 20. The inverter circuit 10 includes an AC interface. The controller 20 is used to: obtain an interface current and a preset reset current of the AC interface; obtain an actual current DC component according to the interface current; determine a target reset current according to the actual current DC component and the preset reset current; and adjust the interface current according to the target reset current.

[0090] See also Figure 8 The present application also provides a photovoltaic energy storage system 200, including a power supply 210 and an inverter 100. The inverter 100 also includes a DC interface. The power supply 210 is connected to the DC interface. And the inverter 100 can execute the current DC V component suppression method described in any of the above embodiments. The power supply 210 includes a photovoltaic module and / or a battery.

[0091] See also Fig. 9 In one embodiment of the present application, a control device 300 is provided, which can be applied to the inverter circuit 10 or an electronic device provided with the inverter circuit 10. The control device 300 includes:

[0092] The first acquisition module 310 is used to acquire the interface current of the AC interface, a given DC component and a preset reset current.

[0093] The second acquisition module 320 is used to acquire the actual current DC component according to the interface current.

[0094] The determination module 330 is used to determine the target reset current according to the actual current DC component, the given DC component and the preset reset current.

[0095] The regulating module 340 is used to regulate the interface current according to the target reset current.

[0096] In the embodiment of the present application, a more detailed functional description of each of the above modules can be referred to the corresponding content of the aforementioned part, which will not be repeated here.

[0097] An embodiment of the present application further provides a computer storage medium, which stores a computer program. When the computer program is executed by a processor, the processor executes the above-mentioned method for suppressing the DC component of current.

[0098] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that contains one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0099] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0100] The present application is not limited to the above specific implementations. A person skilled in the art can easily understand that there are many alternatives to the test fixture of the present application without departing from the principle and scope of the present application. The scope of protection of the present application shall be subject to the content of the claims.

Claims

1. A method for suppressing a DC component of a current, applied to an inverter circuit, wherein the inverter circuit includes an AC interface, characterized in that: The method comprises: Obtaining an interface current, a given DC component, and a preset reset current of the AC interface; Acquiring a DC component of an actual current according to the interface current; Determining an adjusted current value according to the actual current DC component and the given DC component; When the absolute value of the regulated current value is greater than or equal to a preset threshold, determining a target reset current according to the actual current DC component, the given DC component and the preset reset current; The interface current is adjusted according to the target reset current.

2. The method according to claim 1, characterized in that The determining of the target reset current according to the actual current DC component, the given DC component and the preset reset current includes: Determine a compensation current value according to the actual current DC component and the given DC component; The target reset current is determined according to the compensation current value and the preset reset current.

3. The method according to claim 2, characterized in that The preset reset current includes a first preset reset current and a second preset reset current, the target reset current includes a first target reset current and a second target reset current, the first preset reset current and the first target reset current are both less than 0, the second preset reset current and the second target reset current are both greater than 0, and determining the target reset current according to the compensation current value and the preset reset current includes: When the compensation current value is greater than 0, the first preset reset current minus the compensation current value is used as the first target reset current, and the second preset reset current minus the compensation current value is used as the second target reset current; When the compensation current value is less than 0, the first preset reset current plus the compensation current value is used as the first target reset current, and the second preset reset current plus the compensation current value is used as the second target reset current.

4. The method according to claim 2, characterized in that: The determining of the compensation current value according to the actual current DC component and the given DC component includes: The difference obtained by subtracting the given DC component from the actual current DC component is used as the compensation current value.

5. The method according to claim 1, characterized in that The step of determining the adjusted current value according to the actual current DC component and the given DC component includes: Acquire a current deviation value between the actual current DC component and the given DC component; The current deviation value is deviation-adjusted to obtain the adjusted current value.

6. The method according to claim 1, characterized in that After determining the adjustment current value according to the actual current DC component and the given DC component, the method further includes: When the absolute value of the regulated current value is less than the preset threshold, the interface current is regulated according to the regulated current value.

7. The method according to claim 1, characterized in that Before determining the target reset current according to the actual current DC component, the given DC component and the preset reset current, the method further includes: comparing the actual current DC component with the given DC component; When the actual current DC component is equal to the given DC component, the process returns to the step of obtaining the interface current of the AC interface, the given DC component and the preset reset current.

8. An inverter, comprising an inverter circuit and a controller, characterized in that: The inverter circuit includes an AC interface, and the controller is used for: Obtaining an interface current, a given DC component, and a preset reset current of the AC interface; Acquiring a DC component of an actual current according to the interface current; Determining an adjusted current value according to the actual current DC component and the given DC component; When the absolute value of the regulated current value is greater than or equal to a preset threshold, determining a target reset current according to the actual current DC component, the given DC component and the preset reset current; The interface current is adjusted according to the target reset current.

9. A photovoltaic energy storage system, characterized in that: The photovoltaic energy storage system includes a power supply and the inverter as claimed in claim 8, the inverter also includes a DC interface, the power supply is connected to the DC interface, and the power supply includes a photovoltaic module and / or a battery.

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