Device control method

Abstract

The present application is applicable to the field of equipment control technology, and provides an equipment control method, which is applied to a three-phase energy storage inverter parallel system, which includes an inverter host and at least one inverter slave. The equipment control method includes: if the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase total reverse power of the grid-connected access point, calculates all single-phase target reverse powers corresponding to each inverter based on the three-phase total reverse power, obtains the three-phase actual total inverter power, and obtains the three-phase total load power based on the three-phase total reverse power and the three-phase actual total inverter power; the target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the target inverter to work according to the three-phase target total inverter power and the three-phase total load power at the N+1th moment, so that the electric energy reverse flow phenomenon occurring at subsequent moments can be effectively reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of device control, and in particular, to a device control method. Background Art

[0002] In the field of electric energy supply, a three-phase energy storage inverter parallel system is a common system. A three-phase energy storage inverter parallel system refers to a system in which at least two three-phase energy storage inverters are connected in parallel to provide electric energy.

[0003] In a three-phase energy storage inverter parallel system, the ideal situation includes three-phase load balance, that is, the current on each phase is the same and the power is the same. However, in practical applications, the three-phase energy storage inverter parallel system is prone to unbalanced loads, where unbalanced loads refer to unequal currents or unequal powers in each phase of the three-phase load. Unbalanced loads are prone to electric energy reverse flow, which refers to the flow of electric energy from the three-phase energy storage inverter parallel system to the power grid. However, some countries / regions do not allow electric energy to be sent to the power grid at will, that is, they do not allow the occurrence of such electric energy reverse flow. Therefore, how to effectively reduce the occurrence of electric energy reverse flow in a three-phase energy storage inverter parallel system has become an urgent problem to be solved. Summary of the invention

[0004] The embodiment of the present application provides a device control method, which can solve the problem that the current three-phase energy storage inverter parallel system cannot effectively reduce the electric energy backflow phenomenon.

[0005] In a first aspect, an embodiment of the present application provides a device control method, which is applied to a three-phase energy storage inverter parallel system, wherein the three-phase energy storage inverter parallel system includes at least two three-phase energy storage inverters, and the at least two three-phase energy storage inverters include an inverter host and at least one inverter slave. The device control method includes: if the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase reverse current total power of the grid-connected access point; the inverter host calculates all single-phase target reverse current powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse current total power; the inverter host obtains the three-phase actual inverter total power of the three-phase energy storage inverter parallel system at the Nth moment, where N is a large a positive integer greater than or equal to one; the inverter host obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase reverse total power and the three-phase actual inverter total power, and sends the three-phase load total power to the inverter slave; the target inverter calculates the three-phase target inverter total power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter according to the three-phase target inverter total power and the three-phase load total power at the N+1th moment, wherein the N+1th moment is a moment after the Nth moment, and at least one single-phase target reverse power corresponding to the target inverter is greater than or equal to a preset power threshold.

[0006] In a possible implementation of the first aspect, the target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment based on the single-phase target reverse power corresponding to the target inverter, including: the target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment based on the single-phase target reverse power corresponding to the target inverter and the three-phase target total inverter power of the target inverter at the Nth moment.

[0007] In a possible implementation of the first aspect, the target inverter calculates the three-phase target inverter total power of the target inverter at the N+1th moment based on the single-phase target reverse power corresponding to the target inverter and the three-phase target inverter total power of the target inverter at the Nth moment, including: the target inverter adds all single-phase target reverse powers corresponding to the target inverter and the three-phase target inverter total power of the target inverter at the Nth moment, and determines the obtained sum as the three-phase target inverter total power of the target inverter at the N+1th moment.

[0008] In a possible implementation of the first aspect, the target inverter controls the operation of the target inverter according to the three-phase target inverter total power and the three-phase load total power at the N+1th moment, including: the target inverter calculates the power increase or decrease of each single-phase load of the three-phase energy storage inverter parallel system according to the three-phase load total power; calculates the power share factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load and a preset value; corrects the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment according to the power share factor of each single-phase load corresponding to the N+1th moment, and controls the operation of the target inverter according to the corrected single-phase current value.

[0009] In a possible implementation of the first aspect, the power proportion factor of each single-phase load corresponding to the N+1th moment is calculated according to the power increase or decrease of each single-phase load and a preset value, including: calculating the power proportion factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load, a preset value and the power proportion factor of each single-phase load corresponding to the Nth moment.

[0010] In a possible implementation of the first aspect, when the preset value is greater than 0, the power share factor of each single-phase load corresponding to the N+1th moment is calculated based on the power increase or decrease of each single-phase load, the preset value and the power share factor of each single-phase load corresponding to the Nth moment, including: comparing the power increase or decrease of each single-phase load with 0; if the power increase or decrease of the single-phase load is greater than 0, then determining the sum of the power share factor of the single-phase load corresponding to the Nth moment and the preset value as the power share factor of the single-phase load corresponding to the N+1th moment.

[0011] In a possible implementation of the first aspect, the three-phase target inverter total power at the N+1th moment includes multiple single-phase target inverter powers at the N+1th moment, and the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power share factor of each single-phase load corresponding to the N+1th moment, including: performing the following steps for each power share factor of the single-phase load corresponding to the N+1th moment: multiplying the power share factor of the single-phase load corresponding to the N+1th moment by the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment before correction to obtain a product, and the product is the corrected single-phase current value.

[0012] In a possible implementation of the first aspect, the inverter host calculates all single-phase target reverse power corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse total power, including: the inverter host calculates all single-phase target reverse power corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse total power and the number of inverters.

[0013] In a possible implementation of the first aspect, the three-phase total reverse power includes: the first-phase actual reverse power, the second-phase actual reverse power and the third-phase actual reverse power. The three-phase total reverse power, the number of inverters and all single-phase target reverse powers corresponding to each inverter satisfy the following relationship: the quotient obtained by dividing the first-phase actual reverse power by the number of inverters is equal to the first-phase target reverse power corresponding to each inverter, the quotient obtained by dividing the second-phase actual reverse power by the number of inverters is equal to the second-phase target reverse power corresponding to each inverter, and the quotient obtained by dividing the third-phase actual reverse power by the number of inverters is equal to the third-phase target reverse power corresponding to each inverter.

[0014] In a possible implementation of the first aspect, the three-phase total reverse power includes: the actual reverse power of the first phase, the actual reverse power of the second phase, and the actual reverse power of the third phase. The three-phase load total power at the Nth moment includes the first phase load power, the second phase load power, and the third phase load power. The three-phase actual inverter total power includes the first phase actual inverter total power, the second phase actual inverter total power, and the third phase actual inverter total power. The inverter host obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase reverse power and the three-phase actual inverter total power, including: determining the sum of the first phase actual inverter total power and the first phase actual reverse power as the first phase load power; determining the sum of the second phase actual inverter total power and the second phase actual reverse power as the second phase load power; and determining the sum of the third phase actual inverter total power and the third phase actual reverse power as the third phase load power.

[0015] Compared with the prior art, the embodiments of the present application have the following beneficial effects: in the present application, if the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase total reverse power of the grid-connected access point, the inverter host calculates all single-phase target reverse powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase total reverse power, the inverter host obtains the three-phase actual total inverter power of the three-phase energy storage inverter parallel system at the Nth moment, the inverter host obtains the three-phase total load power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase total reverse power and the three-phase actual total inverter power, and sends the three-phase total load power to the inverter slave. The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter according to the three-phase target total inverter power and the three-phase total load power at the N+1th moment. Among them, the N+1th moment is a moment after the Nth moment, and at least one single-phase target reverse flow power corresponding to the target inverter is greater than or equal to the preset power threshold. It can be seen from the above that when an unbalanced load appears in the three-phase energy storage inverter parallel system, the target inverter can timely and accurately adjust the working state of the target inverter according to the three-phase target inverter total power and the three-phase load total power at the N+1th moment, thereby effectively reducing / avoiding the occurrence of power reverse flow in subsequent moments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 any creative work.

[0017] Figure 1 It is a flowchart of a device control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0019] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0020] It should also be understood that the term “or / and” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0021] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0022] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0023] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. Example

[0024] Figure 1 A flow chart of a device control method provided in an embodiment of the present application is shown, wherein the device control method is applied to a three-phase energy storage inverter parallel system, wherein the three-phase energy storage inverter parallel system comprises at least two three-phase energy storage inverters, wherein the at least two three-phase energy storage inverters are connected in parallel, and wherein the at least two three-phase energy storage inverters comprise an inverter host and at least one inverter slave, and the device control method comprises: step S101, step S102, step S103, step S104, and step S105, which are described in detail as follows:

[0025] Step S101: If the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase reverse current total power of the grid-connected access point.

[0026] The three-phase energy storage inverter parallel system being in a grid-connected state means that the three-phase energy storage inverter parallel system is connected to the grid.

[0027] For example, the output ends of all three-phase energy storage inverters in the three-phase energy storage inverter parallel system are connected to the national power grid.

[0028] For the convenience of description, the three-phase energy storage inverter will be referred to as inverter hereinafter.

[0029] As an example but not a limitation, an electric meter is provided in the three-phase energy storage inverter parallel system. If the three-phase energy storage inverter parallel system is in a grid-connected state and the three-phase energy storage inverter parallel system is in a reverse flow control mode, the inverter host obtains the current three-phase reverse flow total power of the grid-connected access point through the electric meter, wherein the reverse flow control mode is aimed at reducing / avoiding the flow of electric energy from the three-phase energy storage inverter parallel system to the grid, that is, the reverse flow control mode is a mode aimed at reducing or even avoiding the reverse flow of electric energy. The three-phase reverse flow total power is specifically the three-phase actual reverse flow total power, and the three-phase actual reverse flow total power includes three single-phase actual reverse flow powers (actual single-phase reverse flow powers). When the single-phase actual reverse flow power is a positive number, it indicates forward flow (no reverse flow); when the single-phase actual reverse flow power is a negative number, it indicates reverse flow. The three single-phase actual reverse flow powers may include the first phase actual reverse flow power, the second phase actual reverse flow power, and the third phase actual reverse flow power.

[0030] Step S102: The inverter host calculates all single-phase target reverse current powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse current total power.

[0031] It should be noted that the target reverse power described herein is the reverse power that the inverter intends to achieve. By analogy, the single-phase target reverse power is the single-phase / per-phase reverse power that the inverter intends to achieve, that is, the single-phase target reverse power is the single-phase / per-phase reverse power target (expected) value that the inverter intends to achieve. The single-phase described herein is at least one of the first phase, the second phase, and the third phase.

[0032] Specifically, the step S102 includes: the inverter host calculates the first phase target reverse power, the second phase target reverse power and the third phase target reverse power corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse total power.

[0033] In some embodiments, the first-phase target reverse power corresponding to each inverter is the same, the second-phase target reverse power corresponding to each inverter is the same, and the third-phase target reverse power corresponding to each inverter is the same. After the inverter host calculates the first-phase target reverse power, the second-phase target reverse power and the third-phase target reverse power corresponding to each inverter in the three-phase energy storage inverter parallel system, it also includes: the inverter host sends the first-phase target reverse power, the second-phase target reverse power and the third-phase target reverse power to each inverter slave.

[0034] In some embodiments, the at least one inverter slave includes two inverter slaves, the two inverter slaves include a first inverter slave and a second inverter slave, and the step S102 includes: the inverter host calculates the first-phase target reverse power corresponding to the inverter host, the second-phase target reverse power corresponding to the inverter host, the third-phase target reverse power corresponding to the inverter host, the first-phase target reverse power corresponding to the first inverter slave, the second-phase target reverse power corresponding to the first inverter slave, the third-phase target reverse power corresponding to the first inverter slave, the first-phase target reverse power corresponding to the second inverter slave, the second-phase target reverse power corresponding to the second inverter slave, and the third-phase target reverse power corresponding to the second inverter slave based on the three-phase reverse total power. The inverter host can also send the first-phase target reverse power corresponding to the first inverter slave, the second-phase target reverse power corresponding to the first inverter slave, and the third-phase target reverse power corresponding to the first inverter slave to the first inverter slave, and send the first-phase target reverse power corresponding to the second inverter slave, the second-phase target reverse power corresponding to the second inverter slave, and the third-phase target reverse power corresponding to the second inverter slave to the second inverter slave.

[0035] Optionally, the step S102 includes: the inverter host calculates all single-phase target reverse power corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse total power and the number of inverters.

[0036] The number of inverters is the number of inverters connected in parallel in the three-phase energy storage inverter parallel system.

[0037] In some embodiments, the three-phase total reverse power includes: the first-phase actual reverse power, the second-phase actual reverse power and the third-phase actual reverse power. The three-phase total reverse power, the number of inverters and all single-phase target reverse powers corresponding to each inverter (the first-phase target reverse power corresponding to each inverter, the second-phase target reverse power corresponding to each inverter, and the third-phase target reverse power corresponding to each inverter) satisfy the following relationship: the quotient obtained by dividing the first-phase actual reverse power by the number of inverters is equal to the first-phase target reverse power corresponding to each inverter, the quotient obtained by dividing the second-phase actual reverse power by the number of inverters is equal to the second-phase target reverse power corresponding to each inverter, and the quotient obtained by dividing the third-phase actual reverse power by the number of inverters is equal to the third-phase target reverse power corresponding to each inverter. In this way, the reasonable allocation of the single-phase target reverse power corresponding to each inverter can be efficiently achieved.

[0038] Step S103: the inverter host obtains the actual three-phase total inverter power of the three-phase energy storage inverter parallel system at the Nth moment.

[0039] Wherein, N is a positive integer greater than or equal to one.

[0040] For example, the Nth moment may be the current moment.

[0041] As an example but not limitation, a parallel communication bus is provided in the three-phase energy storage inverter parallel system, and the inverter host obtains the three-phase actual total inverter power of the three-phase energy storage inverter parallel system at the Nth moment through the parallel communication bus. The three-phase actual total inverter power is the actual three-phase total inverter power. The three-phase actual total inverter power includes the first-phase actual total inverter power, the second-phase actual total inverter power and the third-phase actual total inverter power. The actual total inverter power described in this article is the actual total inverter power. The first-phase actual total inverter power is equal to the sum of the first-phase actual inverter powers of all inverters in the three-phase energy storage inverter parallel system, the second-phase actual total inverter power is equal to the sum of the second-phase actual inverter powers of all inverters in the three-phase energy storage inverter parallel system, and the third-phase actual total inverter power is equal to the sum of the third-phase actual inverter powers of all inverters in the three-phase energy storage inverter parallel system.

[0042] Step S104: The inverter master obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase reverse total power and the three-phase actual inverter total power, and sends the three-phase load total power to the inverter slave.

[0043] The three-phase load total power includes the first-phase load power, the second-phase load power and the third-phase load power.

[0044] As an example but not limitation, the inverter host obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the first moment based on the three-phase reverse total power and the three-phase actual inverter total power, and synchronously sends the three-phase load total power to all inverter slaves of the three-phase energy storage inverter parallel system.

[0045] In some embodiments, the three-phase total reverse power includes: the actual reverse power of the first phase, the actual reverse power of the second phase, and the actual reverse power of the third phase. The three-phase load total power at the Nth moment includes the first phase load power, the second phase load power, and the third phase load power. The three-phase actual inverter total power includes the first phase actual inverter total power, the second phase actual inverter total power, and the third phase actual inverter total power. The inverter host obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase total reverse power and the three-phase actual inverter total power, including: determining the sum of the first phase actual inverter total power and the first phase actual reverse power as the first phase load power; determining the sum of the second phase actual inverter total power and the second phase actual reverse power as the second phase load power; and determining the sum of the third phase actual inverter total power and the third phase actual reverse power as the third phase load power.

[0046] Step S105: The target inverter calculates the three-phase target inverter total power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter according to the three-phase target inverter total power at the N+1th moment and the three-phase load total power. The N+1th moment is a moment after the Nth moment, and at least one single-phase target reverse power corresponding to the target inverter is greater than or equal to a preset power threshold.

[0047] That is, the target inverter is: in the three-phase energy storage inverter parallel system, an inverter whose at least one single-phase target reverse current power is greater than or equal to a preset power threshold.

[0048] As an example but not limitation, if at least one single-phase target reverse power corresponding to the inverter master is greater than or equal to a preset power threshold, the target inverter includes the inverter master; if at least one single-phase target reverse power corresponding to the inverter slave is greater than or equal to the preset power threshold, the target inverter includes the inverter master. Alternatively, if at least one single-phase target reverse power corresponding to the first inverter slave is greater than or equal to the preset power threshold, the target inverter includes the first inverter slave; if at least one single-phase target reverse power corresponding to the second inverter slave is greater than or equal to the preset power threshold, the target inverter includes the second inverter slave.

[0049] Specifically, the step S105 includes: each target inverter performs the following steps: the target inverter calculates the three-phase target inverter total power of the target inverter at the N+1th moment according to each single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter according to the three-phase target inverter total power at the N+1th moment and the three-phase load total power. The time length between the N+1th moment and the Nth moment is equal to the preset time length.

[0050] For example, assuming that there are at least two target inverters, including an inverter host and a first inverter slave, the inverter host calculates the three-phase target total inverter power of the inverter host at the N+1th moment according to each single-phase target reverse current power corresponding to the inverter host, and the inverter host controls the operation of the inverter host according to the three-phase target total inverter power of the inverter host at the N+1th moment and the three-phase load total power; the first inverter slave calculates the three-phase target total inverter power of the first inverter slave at the N+1th moment according to each single-phase target reverse current power corresponding to the first inverter slave, and the first inverter slave controls the operation of the first inverter slave according to the three-phase target total inverter power of the first inverter slave at the N+1th moment and the three-phase load total power.

[0051] Optionally, the target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, including: the target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter and the three-phase target total inverter power of the target inverter at the Nth moment. The three-phase target total inverter power of the target inverter at the N+1th moment calculated in this way is more scientific and can better optimize the prevention and control effect of electric energy reverse flow.

[0052] For example, assuming that there are at least two target inverters, including an inverter host and a first inverter slave, the inverter host calculates the three-phase target total inverter power of the inverter host at the N+1th moment based on the single-phase target reverse power corresponding to the inverter host and the three-phase target total inverter power of the inverter host at the Nth moment; the first inverter slave calculates the three-phase target total inverter power of the first inverter slave at the N+1th moment based on the single-phase target reverse power corresponding to the first inverter slave and the three-phase target total inverter power of the first inverter slave at the Nth moment.

[0053] Optionally, the target inverter calculates the three-phase target inverter total power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter and the three-phase target inverter total power of the target inverter at the Nth moment, including: the target inverter adds all the single-phase target reverse power corresponding to the target inverter and the three-phase target inverter total power of the target inverter at the Nth moment, and determines the obtained sum as the three-phase target inverter total power of the target inverter at the N+1th moment. In this way, the target inverter can accurately calculate the three-phase target inverter total power at the N+1th moment.

[0054] Specifically, each target inverter performs the following steps: adding the first-phase target reverse power corresponding to the target inverter, the second-phase target reverse power corresponding to the target inverter, the third-phase target reverse power corresponding to the target inverter, and the three-phase target total inverter power of the target inverter at the Nth moment, and determining the obtained sum as the three-phase target total inverter power of the target inverter at the N+1th moment.

[0055] For example, assuming that there are at least two target inverters, including an inverter master and a first inverter slave, the inverter master calculates a first sum, the first sum refers to: the sum of the first-phase target reverse power corresponding to the inverter master, the second-phase target reverse power corresponding to the inverter master, the third-phase target reverse power corresponding to the inverter master, and the three-phase target total inverter power of the inverter master at the Nth moment, and the first sum is determined as the three-phase target total inverter power of the inverter master at the N+1th moment. The first inverter slave calculates a second sum, the second sum refers to: the sum of the first-phase target reverse power corresponding to the first inverter slave, the second-phase target reverse power corresponding to the first inverter slave, the third-phase target reverse power corresponding to the first inverter slave, and the three-phase target total inverter power of the first inverter slave at the Nth moment, and the second sum is determined as the three-phase target total inverter power of the first inverter slave at the N+1th moment.

[0056] Optionally, the target inverter controls the operation of the target inverter according to the three-phase target inverter total power and the three-phase load total power at the N+1th moment, including: the target inverter calculates the power increase or decrease of each single-phase load of the three-phase energy storage inverter parallel system according to the three-phase load total power, calculates the power share factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load and a preset value, corrects the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment according to the power share factor of each single-phase load corresponding to the N+1th moment, and controls the operation of the target inverter according to the corrected single-phase current value.

[0057] It should be noted that the preset value and the preset power threshold are different values.

[0058] The target inverter calculates the increase or decrease of each single-phase load power of the three-phase energy storage inverter parallel system according to the total power of the three-phase load, which may include: calculating the increase or decrease of the first-phase load power of the three-phase energy storage inverter parallel system according to the first-phase load power and the load power average, the load power average is equal to the sum of the first-phase load power, the second-phase load power and the third-phase load power divided by 3 to obtain the quotient, that is, the load power average is equal to the average of the first-phase load power, the second-phase load power and the third-phase load power, the first-phase load power is equal to the first-phase load power, the second-phase load power and the third-phase load power. The power increase or decrease is equal to the difference obtained by subtracting the load power average value from the first phase load power; the second phase load power increase or decrease of the three-phase energy storage inverter parallel system is calculated according to the second phase load power and the load power average value, and the second phase load power increase or decrease is equal to the difference obtained by subtracting the load power average value from the second phase load power; the third phase load power increase or decrease of the three-phase energy storage inverter parallel system is calculated according to the third phase load power and the load power average value; the third phase load power increase or decrease is equal to the difference obtained by subtracting the load power average value from the third phase load power.

[0059] In addition, the power proportion factor of each single-phase load corresponding to the N+1th moment is calculated according to the power increase or decrease of each single-phase load and the preset value, and the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power proportion factor of each single-phase load corresponding to the N+1th moment, and the operation of the target inverter is controlled according to the corrected single-phase current value, which may include: calculating the power proportion factor of the first-phase load corresponding to the N+1th moment according to the first-phase load power and the preset value, and correcting the first-phase current value corresponding to the three-phase target inverter total power at the N+1th moment according to the power proportion factor of the first-phase load corresponding to the N+1th moment; and controlling the operation of the target inverter according to the corrected single-phase current value according to the second phase load power and the preset value. According to the power proportion factor of the second phase load corresponding to the N+1th moment, the second phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power proportion factor of the second phase load corresponding to the N+1th moment; according to the third phase load power and the preset value, the power proportion factor of the third phase load corresponding to the N+1th moment is calculated, and the third phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power proportion factor of the third phase load corresponding to the N+1th moment; and the target inverter is controlled to operate according to the corrected first phase current value, the corrected second phase current value and the corrected third phase current value.

[0060] When the three-phase energy storage inverter parallel system is in a three-phase load balance state, the power proportion factor of the first phase load, the power proportion factor of the second phase load, and the power proportion factor of the third phase load are all equal to 1 / 3.

[0061] Optionally, calculating the power share factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load and a preset value includes: calculating the power share factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load, a preset value and the power share factor of each single-phase load corresponding to the Nth moment.

[0062] The preset value may be greater than 0 or less than 0.

[0063] In some embodiments, when the preset value is greater than 0, the power proportion factor of each single-phase load corresponding to the N+1th moment is calculated according to the power increase or decrease of each single-phase load, the preset value, and the power proportion factor of each single-phase load corresponding to the Nth moment, including:

[0064] Compare the power increase or decrease of each single-phase load with 0;

[0065] If the increase or decrease in the power of the single-phase load is greater than 0, the sum of the power proportion factor of the single-phase load corresponding to the Nth moment and the preset value is determined as the power proportion factor of the single-phase load corresponding to the N+1th moment;

[0066] The calculation of the power share factor of each single-phase load corresponding to the N+1th moment based on the power increase or decrease of each single-phase load, the preset value and the power share factor of each single-phase load corresponding to the Nth moment may also include: if the power increase or decrease of the single-phase load is less than 0, then determining the difference between the power share factor of the single-phase load corresponding to the Nth moment and the preset value as the power share factor of the single-phase load corresponding to the N+1th moment.

[0067] When the three-phase energy storage inverter parallel system is in an unbalanced load condition, the single-phase load power increase or decrease is greater than 0 or the single-phase load power increase or decrease is less than 0.

[0068] For example, assuming that the preset value is greater than 0 and the power increase or decrease of the first phase load is greater than 0, the sum of the power proportion factor of the first phase load corresponding to the Nth moment and the preset value is determined as the power proportion factor of the first phase load corresponding to the N+1th moment. Since the power increase or decrease of the first phase load is greater than 0, the power increase or decrease of the second phase load or / and the power increase or decrease of the third phase load is less than 0. Assuming that the power increase or decrease of the second phase load is less than 0, the difference obtained by subtracting the preset value from the power proportion factor of the second phase load corresponding to the Nth moment is determined as the power proportion factor of the second phase load corresponding to the N+1th moment.

[0069] In some embodiments, when the preset value is less than 0, the power share factor of each single-phase load corresponding to the N+1th moment is calculated based on the power increase or decrease of each single-phase load, the preset value and the power share factor of each single-phase load corresponding to the Nth moment, including: comparing the power increase or decrease of each single-phase load with 0; if the power increase or decrease of the single-phase load is greater than 0, then determining the difference between the power share factor of the single-phase load corresponding to the Nth moment and the preset value as the power share factor of the single-phase load corresponding to the N+1th moment; the power share factor of each single-phase load corresponding to the N+1th moment is calculated based on the power increase or decrease of each single-phase load, the preset value and the power share factor of each single-phase load corresponding to the Nth moment, and may also include: if the power increase or decrease of the single-phase load is less than 0, then determining the sum of the power share factor of the single-phase load corresponding to the Nth moment and the preset value as the power share factor of the single-phase load corresponding to the N+1th moment.

[0070] In some embodiments, the three-phase target inverter total power at the N+1th moment includes multiple single-phase target inverter powers at the N+1th moment, and the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power proportion factor of each single-phase load corresponding to the N+1th moment, including: performing the following steps for each single-phase load corresponding to the N+1th moment: multiplying the power proportion factor of the single-phase load corresponding to the N+1th moment by the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment before correction to obtain a product, and the product is the corrected single-phase current value (corresponding to the three-phase target inverter total power at the N+1th moment).

[0071] In this way, the single-phase current value can be accurately corrected.

[0072] For example, the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment includes the first phase current value, the second phase current value and the third phase current value. The result obtained by multiplying the power proportion factor of the first phase load at the N+1th moment by the first phase current value before correction is determined as the corrected first phase current value; the result obtained by multiplying the power proportion factor of the second phase load at the N+1th moment by the second phase current value before correction is determined as the corrected second phase current value; the result obtained by multiplying the power proportion factor of the third phase load at the N+1th moment by the third phase current value before correction is determined as the corrected third phase current value.

[0073] The single-phase current value before correction (corresponding to the three-phase target inverter total power at the N+1th moment) is calculated based on the three-phase target inverter total power at the N+1th moment and the specified voltage value. The inverter control inner loop of each inverter has a front-end entrance, and the single-phase current value is the single-phase current value of the inverter control inner loop.

[0074] In the present application, if the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase total reverse power of the grid-connected access point, and the inverter host calculates all single-phase target reverse powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase total reverse power. The inverter host obtains the three-phase actual total inverter power of the three-phase energy storage inverter parallel system at the Nth moment, and the inverter host obtains the three-phase total load power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase total reverse power and the three-phase actual total inverter power, and sends the three-phase total load power to the inverter slave. The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter according to the three-phase target total inverter power at the N+1th moment and the three-phase total load power. Among them, the N+1th moment is a moment after the Nth moment, and at least one single-phase target reverse flow power corresponding to the target inverter is greater than or equal to the preset power threshold. As can be seen from the above, when an unbalanced load appears in the three-phase energy storage inverter parallel system, the target inverter can timely and accurately adjust the working state of the target inverter according to the three-phase target inverter total power and the three-phase load total power at the N+1th moment, thereby effectively reducing / avoiding the occurrence of power reverse flow phenomenon at subsequent moments.

[0075] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0076] The embodiments described above 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, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A device control method, characterized in that: The device control method is applied to a three-phase energy storage inverter parallel system, wherein the three-phase energy storage inverter parallel system includes at least two three-phase energy storage inverters, wherein the at least two three-phase energy storage inverters include an inverter master and at least one inverter slave, and the device control method includes: If the three-phase energy storage inverter parallel system is in a grid-connected state, the inverter host obtains the three-phase reverse current total power of the grid-connected access point; The inverter host calculates all single-phase target reverse current powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse current total power, and all single-phase target reverse current powers corresponding to each inverter include: the first-phase target reverse current power corresponding to each inverter, the second-phase target reverse current power corresponding to each inverter, and the third-phase target reverse current power corresponding to each inverter, the first-phase target reverse current power corresponding to each inverter is the same, the second-phase target reverse current power corresponding to each inverter is the same, and the third-phase target reverse current power corresponding to each inverter is the same. After the inverter host calculates the first-phase target reverse current power, the second-phase target reverse current power, and the third-phase target reverse current power, it also includes: the inverter host sends the first-phase target reverse current power, the second-phase target reverse current power, and the third-phase target reverse current power to each inverter slave; The inverter host obtains the three-phase actual total inverter power of the three-phase energy storage inverter parallel system at the Nth moment, where N is a positive integer greater than or equal to one; The inverter master obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase reverse total power and the three-phase actual inverter total power, and sends the three-phase load total power at the Nth moment to the inverter slave; The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment based on the single-phase target reverse power corresponding to the target inverter, and the target inverter controls the operation of the target inverter based on the three-phase target total inverter power at the N+1th moment and the three-phase total load power at the Nth moment, wherein the N+1th moment is a moment after the Nth moment, and at least one single-phase target reverse power corresponding to the target inverter is greater than or equal to a preset power threshold.

2. The device control method according to claim 1, characterized in that: The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter, including: The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter and the three-phase target total inverter power of the target inverter at the Nth moment.

3. The device control method according to claim 2, characterized in that: The target inverter calculates the three-phase target total inverter power of the target inverter at the N+1th moment according to the single-phase target reverse power corresponding to the target inverter and the three-phase target total inverter power of the target inverter at the Nth moment, including: The target inverter adds all single-phase target reverse current powers corresponding to the target inverter and the three-phase target inverter total power of the target inverter at the Nth moment, and determines the obtained sum as the three-phase target inverter total power of the target inverter at the N+1th moment.

4. The device control method according to claim 1, characterized in that: The target inverter controls the operation of the target inverter according to the three-phase target inverter total power at the N+1th moment and the three-phase load total power at the Nth moment, including: The target inverter calculates the power increase or decrease of each single-phase load of the three-phase energy storage inverter parallel system according to the total power of the three-phase load at the Nth moment; calculates the power share factor of each single-phase load corresponding to the N+1th moment according to the power increase or decrease of each single-phase load and a preset value; corrects the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment according to the power share factor of each single-phase load corresponding to the N+1th moment, and controls the operation of the target inverter according to the corrected single-phase current value.

5. The device control method according to claim 4, characterized in that: The calculating, according to the power increase or decrease of each single-phase load and a preset value, the power proportion factor of each single-phase load corresponding to the N+1th moment includes: The power proportion factor of each single-phase load corresponding to the N+1th moment is calculated according to the power increase or decrease of each single-phase load, the preset value and the power proportion factor of each single-phase load corresponding to the Nth moment.

6. The device control method according to claim 5, characterized in that: When the preset value is greater than 0, the power proportion factor of each single-phase load corresponding to the N+1th moment is calculated according to the power increase or decrease of each single-phase load, the preset value and the power proportion factor of each single-phase load corresponding to the Nth moment, including: Compare the power increase or decrease of each single-phase load with 0; If the increase or decrease in the single-phase load power is greater than 0, the sum of the power proportion factor of the single-phase load corresponding to the Nth moment and the preset value is determined as the power proportion factor of the single-phase load corresponding to the N+1th moment.

7. The device control method according to claim 4, characterized in that: The three-phase target inverter total power at the N+1th moment includes multiple single-phase target inverter powers at the N+1th moment, and the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment is corrected according to the power proportion factor of each single-phase load corresponding to the N+1th moment, including: The following steps are performed for each power proportion factor of the single-phase load corresponding to the N+1th moment: The power proportion factor of the single-phase load corresponding to the N+1th moment is multiplied by the single-phase current value corresponding to the three-phase target inverter total power at the N+1th moment before correction to obtain a product, and the product is the corrected single-phase current value.

8. The device control method according to claim 1, characterized in that: The inverter host calculates all single-phase target reverse current powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse current total power, including: The inverter host calculates all single-phase target reverse current powers corresponding to each inverter in the three-phase energy storage inverter parallel system based on the three-phase reverse current total power and the number of inverters.

9. The device control method according to claim 8, characterized in that: The three-phase total reverse power includes: the first-phase actual reverse power, the second-phase actual reverse power and the third-phase actual reverse power. The three-phase total reverse power, the number of inverters and all single-phase target reverse powers corresponding to each inverter satisfy the following relationship: the quotient obtained by dividing the first-phase actual reverse power by the number of inverters is equal to the first-phase target reverse power corresponding to each inverter, the quotient obtained by dividing the second-phase actual reverse power by the number of inverters is equal to the second-phase target reverse power corresponding to each inverter, and the quotient obtained by dividing the third-phase actual reverse power by the number of inverters is equal to the third-phase target reverse power corresponding to each inverter.

10. The device control method according to claim 1, characterized in that: The three-phase reverse total power includes: the first phase actual reverse power, the second phase actual reverse power and the third phase actual reverse power, the three-phase load total power at the Nth moment includes the first phase load power, the second phase load power and the third phase load power, the three-phase actual inverter total power includes the first phase actual inverter total power, the second phase actual inverter total power and the third phase actual inverter total power, the inverter host obtains the three-phase load total power of the three-phase energy storage inverter parallel system at the Nth moment based on the three-phase reverse total power and the three-phase actual inverter total power, including: Determine the sum of the first phase actual total inverter power and the first phase actual reverse current power as the first phase load power; Determine the sum of the second phase actual total inverter power and the second phase actual reverse current power as the second phase load power; The sum of the third-phase actual total inverter power and the third-phase actual reverse power is determined as the third-phase load power.

Images