Control method and device of three-phase inverter, three-phase inverter and power supply system

Abstract

The invention discloses a control method and device of a three-phase inverter, the three-phase inverter and a power supply system, and belongs to the technical field of inverters. The control method of the three-phase inverter comprises the following steps: under the condition that the three-phase inverter operates in a three-phase working mode, in response to single-phase default of a power grid, obtaining phase sequence detection information of the remaining two phases in the power grid; based on the phase sequence detection information, phase angle detection information of the remaining two phases is determined; and controlling the three-phase inverter to operate in a two-phase working mode based on the phase angle detection information. The method comprises the steps of obtaining phase sequence detection information of the remaining two phases, determining phase angle detection information of the remaining two phases, and controlling a three-phase inverter to be switched from a three-phase working mode to a two-phase working mode under the condition that a single-phase power failure occurs in a power grid, so that two-phase output of the three-phase inverter is matched with the remaining two-phase operation phases of the power grid, and the power failure of the power grid is avoided. The operation state of the three-phase inverter is maintained, and the waste of photovoltaic power generation resources is reduced.

Description

Technical Field

[0001] This application belongs to the field of inverter technology, and particularly relates to a control method, device, three-phase inverter and power supply system for a three-phase inverter. Background Technology

[0002] The application of photovoltaic and energy storage systems is becoming increasingly widespread. For three-phase photovoltaic and energy storage systems, their operation depends on being connected to a corresponding type of power grid and the power grid being normal. That is, the system can only operate normally when it is connected to a three-phase power grid and all three phases of the power grid are normal.

[0003] However, when a single-phase power outage occurs in the power grid, the system's protection mechanism will still trigger shutdown, causing the system to stop operating, even if the remaining phases of the grid remain normal. Existing control strategies severely restrict the reliability of photovoltaic-storage power supply, resulting in a waste of photovoltaic power generation resources and making it difficult for energy storage devices to provide backup power during partial grid failures. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a control method, device, three-phase inverter, and power supply system for a three-phase inverter, which can maintain the operation of the inverter in the event of a single-phase power outage in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0005] In a first aspect, this application provides a control method for a three-phase inverter connected to a power grid, the method comprising: When the three-phase inverter is operating in three-phase mode, in response to a single-phase loss in the power grid, the phase sequence detection information of the remaining two phases in the power grid is obtained; Based on the phase sequence detection information, the phase angle detection information of the remaining two phases is determined; Based on the phase angle detection information, the three-phase inverter is controlled to operate in two-phase mode.

[0006] According to the control method of the three-phase inverter in this application, when a single-phase power failure occurs in the power grid, the phase sequence detection information of the remaining two phases is obtained, the phase angle detection information of the remaining two phases is determined, and the three-phase inverter is controlled to switch from three-phase working mode to two-phase working mode, so that the two-phase output of the three-phase inverter matches the remaining two operating phases of the power grid, maintains the operating state of the three-phase inverter, and reduces the waste of photovoltaic power generation resources.

[0007] According to one embodiment of this application, the remaining two phases include a first target phase and a second target phase, and the step of obtaining the phase sequence detection information of the remaining two phases in the power grid includes: The phase of the first target phase is delayed by 90 degrees to establish the first virtual phase; Obtain the integral value of the voltage product of the first virtual phase and the second target phase over one power frequency cycle; Based on the sign of the integral value, the phase sequence of the remaining two phases in the power grid is determined.

[0008] According to one embodiment of this application, determining the phase sequence of the remaining two phases in the power grid based on the sign of the integral value includes: If the sign of the integral value is positive, the phase sequence of the remaining two phases in the power grid is determined to be positive. Alternatively, if the sign of the integral value is negative, the phase sequence of the remaining two phases in the power grid is determined to be negative.

[0009] According to one embodiment of this application, the remaining two phases include a first target phase and a second target phase, and determining the phase angle detection information of the remaining two phases based on the phase sequence detection information includes: Phase-locked to the first target phase, and the phase angle of the first target phase is obtained; Based on the phase angle of the first target phase and the phase sequence detection information, the phase angle of the second target phase is determined, and the phase angles of the first target phase and the second target phase differ by 120 degrees.

[0010] According to one embodiment of this application, the method further includes: When the three-phase inverter is operating in three-phase mode, in response to the occurrence of two-phase loss in the power grid, the three-phase inverter is controlled to operate in single-phase mode.

[0011] According to one embodiment of this application, the three-phase inverter is connected to the power grid via a three-phase grid-connected switching device, and the method further includes: When the three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, in response to a fault in the remaining phase of the grid, the three-phase grid-connected / off-grid switching device is controlled to disconnect the three-phase inverter from the grid and control the three-phase inverter to operate in off-grid mode.

[0012] According to one embodiment of this application, after the grid-connected switching device is disconnected from the power grid, the method further includes: When the remaining phases are restored to power, the output of the three-phase inverter is controlled based on the operating parameters of the remaining phases of the power grid. When the operating parameters of the three-phase inverter and the remaining phase of the power grid are synchronized, the three-phase grid-connected switching device is controlled to establish the connection between the three-phase inverter and the power grid, and the three-phase inverter is controlled to operate in grid-connected mode.

[0013] According to one embodiment of this application, the method further includes: When the three-phase inverter is operating in the three-phase working mode, in response to a phase loss in the power grid, the power conversion circuit in the three-phase inverter corresponding to the phase loss in the power grid is controlled to stop working.

[0014] Secondly, this application provides a control method for a two-phase inverter connected to a power grid, the method comprising: Obtain phase sequence detection information for two phases in the power grid; Based on the phase sequence detection information, the phase angle detection information of the two phases is determined; Based on the phase angle detection information, the two-phase inverter is controlled to operate in a two-phase working mode; In response to a single-phase loss in the power grid, the two-phase inverter is controlled to operate in single-phase mode.

[0015] According to the control method of the two-phase inverter in this application, by acquiring the phase sequence detection information and phase angle detection information of the two phases of the power grid, the two-phase output of the two-phase inverter is controlled according to the phase sequence and phase angle of the two-phase operating phases. When a single phase loss occurs in the power grid, the two-phase inverter is controlled to operate in a single-phase working mode. This can maintain the operating state of the two-phase inverter in the event of a single phase power failure in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0016] Thirdly, this application provides a control device for a three-phase inverter, the three-phase inverter being connected to the power grid, the control device comprising: The first processing module is used to obtain the phase sequence detection information of the remaining two phases in the power grid in response to a single phase loss when the three-phase inverter is operating in three-phase mode. The second processing module is used to determine the phase angle detection information of the remaining two phases based on the phase sequence detection information; The third processing module is used to control the three-phase inverter to operate in two-phase mode based on the phase angle detection information.

[0017] Fourthly, this application provides a three-phase inverter connected to the power grid, the three-phase inverter including the control device for the three-phase inverter as described in the third aspect above.

[0018] Fifthly, this application provides a control device for a two-phase inverter connected to the power grid, the control device comprising: The fourth processing module is used to acquire phase sequence detection information of two phases in the power grid; The fifth processing module is used to determine the phase angle detection information of the two phases based on the phase sequence detection information; The sixth processing module is used to control the two-phase inverter to operate in a two-phase working mode based on the phase angle detection information; The seventh processing module is used to control the two-phase inverter to operate in single-phase mode in response to a single-phase loss in the power grid.

[0019] In a sixth aspect, this application provides a two-phase inverter connected to the power grid, the two-phase inverter including the control device for the two-phase inverter as described in the fifth aspect above.

[0020] In a seventh aspect, this application provides a power supply system, comprising: The equipment includes a power supply device, a photovoltaic power generation device, and an energy storage device. The AC terminal of the power supply device is used to connect to the power grid, and the DC terminal of the power supply device is connected to the photovoltaic power generation device and the energy storage device. The power supply equipment is either a three-phase inverter as described in the fourth aspect above, or a two-phase inverter as described in the sixth aspect above.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating the control method for a three-phase inverter provided in an embodiment of this application; Figure 2 This is a flowchart illustrating the control method for a two-phase inverter provided in an embodiment of this application. Figure 3 This is a schematic diagram of the control device for a three-phase inverter provided in an embodiment of this application; Figure 4 This is a schematic diagram of the control device for a two-phase inverter provided in an embodiment of this application; Figure 5 This is a schematic diagram of the power supply system provided in an embodiment of this application; Figure 6 This is a schematic diagram of a single-phase loss in a power grid provided in an embodiment of this application; Figure 7 This is a schematic diagram of the grid connection disconnection of the grid switching device provided in the embodiments of this application; Figure 8 This is a schematic diagram showing the power conversion circuit provided in the embodiment of this application stopping operation; Figure 9This is a schematic diagram of the three-phase phase angle relationship provided in the embodiments of this application; Figure 10 This is a schematic diagram of the natural two-phase phase angle relationship provided in the embodiments of this application; Figure 11 This is a schematic diagram showing the positive three-phase sequence relationship provided in the embodiments of this application; Figure 12 This is a schematic diagram showing the negative three-phase sequence relationship provided in the embodiments of this application; Figure 13 This is a schematic diagram showing the positive phase sequence relationship of the two phases provided in the embodiments of this application; Figure 14 This is a schematic diagram showing that the two-phase sequence relationship is negative, provided in an embodiment of this application. Figure 15 This is one of the virtual phase diagrams provided in the embodiments of this application; Figure 16 This is the second virtual phase schematic diagram provided in the embodiments of this application; Figure 17 This is a schematic diagram of a Bode plot provided in an embodiment of this application; Figure 18 This is one of the schematic diagrams showing the remaining two-phase phase angle relationship provided in the embodiments of this application; Figure 19 This is the second schematic diagram of the remaining two phase angle relationship provided in the embodiments of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The control method for a three-phase inverter, the control method for a two-phase inverter, the control device for a three-phase inverter, the three-phase inverter, the control device for a two-phase inverter, the two-phase inverter, and the power supply system provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0026] The control method for a three-phase inverter provided in this application embodiment can be executed by a three-phase inverter or a functional module or entity within a three-phase inverter that can implement the control method for the three-phase inverter.

[0027] The three-phase inverter is connected to the power grid, with its AC terminal connected to the power grid and its DC terminal connected to the photovoltaic power generation device 510 and / or energy storage device 520.

[0028] It should be noted that the power grid connected to the three-phase inverter is a three-phase AC system. The three-phase inverter can output AC power in three phases, with a phase difference of 120 degrees between them, which can include phase L1, phase L2, and phase L3. The three-phase four-wire inverter also includes the neutral line N line.

[0029] In related technologies, when a single-phase power outage occurs due to an imbalance fault, even if the remaining phases of the grid remain normal, the system's protection mechanism will still trigger shutdown, causing the system to stop operating. This control strategy severely restricts the reliability of photovoltaic-storage power supply, wastes photovoltaic power generation resources, and makes it difficult for energy storage devices to provide backup power when there is a partial grid failure.

[0030] This application provides a control method for a three-phase inverter, which can maintain the inverter's operation and reduce the waste of photovoltaic power generation resources when a single-phase power failure occurs in the power grid.

[0031] like Figure 1 As shown, the control method of the three-phase inverter includes steps 110, 120 and 130.

[0032] Step 110: When the three-phase inverter is operating in three-phase mode, in response to a single-phase loss in the power grid, obtain the phase sequence detection information of the remaining two phases in the power grid.

[0033] It is understandable that a three-phase inverter operating in three-phase mode means that the three-phase inverter can output AC power in three phases.

[0034] In this step, the three-phase inverter monitors the operation of the power grid in real time. When it detects that a phase in the power grid has lost power, i.e. a single phase loss occurs in the power grid, it obtains the phase sequence detection information of the remaining two phases in the power grid.

[0035] In some embodiments, it can be determined whether a power outage has occurred based on whether the voltage sampling value of each phase at the grid terminal is lower than a preset threshold.

[0036] Taking a three-phase inverter as an example of a photovoltaic-storage inverter, such as Figure 6 As shown, the photovoltaic-storage inverter detected that the voltage sampling value of phase L1 was lower than the preset threshold, resulting in a phase loss of phase L1 in the power grid, with phases L2 and L3 remaining in the power grid.

[0037] In other embodiments, the remaining phases of the power grid can be preset. For example, if a region originally has a three-phase power grid, and during actual wiring, the three-phase inverter is connected to two of the three phases, that is, the other phase of the three phases is a power-off phase relative to the three-phase inverter. The relevant information of the power-off phase and the remaining phase can be preset in the control system of the three-phase inverter.

[0038] It should be noted that the phase sequence detection information of the remaining two phases in the power grid refers to the phase sequence of the remaining two operating phases in the power grid. The three-phase inverter is connected to the power grid, and the operating status of the three-phase inverter (such as the direction of motor rotation) is determined based on the phase sequence of the power grid.

[0039] Step 120: Based on the phase sequence detection information, determine the phase angle detection information of the remaining two phases.

[0040] In this step, the phase angles of the remaining two operating phases are calculated based on the phase sequence of the remaining two operating phases in the power grid, thus obtaining the phase angle detection information of the remaining two phases.

[0041] It should be noted that, as Figure 9 As shown, for a three-phase AC power grid, the three phases are 120 degrees apart. L1 and L2 are 120 degrees apart, L2 and L3 are 120 degrees apart, and L3 and L1 are 120 degrees apart. When L1 loses power, the absolute value of the phase difference between the remaining two phases L2 and L3 is still 120 degrees.

[0042] In this embodiment, the phase sequence detection information can characterize the phase order of the remaining two operating phases. Based on the known phase order, and according to the absolute value of the phase difference between the remaining two phases being 120 degrees, the phase angle detection information of the remaining two operating phases can be determined. The phase angle detection information is used to characterize the phase order and phase angle of the remaining two operating phases.

[0043] Step 130: Based on the phase angle detection information, control the three-phase inverter to operate in two-phase mode.

[0044] In this step, based on the phase angle detection information of the remaining two operating phases, the phase sequence and phase angle of the remaining two operating phases are determined, and the three-phase inverter is controlled to operate in two-phase working mode.

[0045] Among them, the three-phase inverter operating in two-phase working mode means that the three-phase inverter can output two phases of AC power.

[0046] In this embodiment, when a single-phase power outage occurs in the power grid, the three-phase inverter first detects the phase sequence of the remaining two operating phases, then determines the phase angle of the remaining two operating phases based on the phase sequence. According to the phase sequence and phase angle of the remaining two operating phases, the three-phase inverter is controlled to switch from three-phase output to two-phase output, so that the two-phase output of the three-phase inverter matches the remaining two operating phases of the power grid. This can maintain the operating state of the three-phase inverter in the event of a single-phase power outage in the power grid, reducing the waste of photovoltaic power generation resources.

[0047] According to the control method of the three-phase inverter provided in the embodiments of this application, when a single-phase power failure occurs in the power grid, the phase sequence detection information of the remaining two phases is obtained, the phase angle detection information of the remaining two phases is determined, and the three-phase inverter is controlled to switch from the three-phase working mode to the two-phase working mode, so that the two-phase output of the three-phase inverter matches the remaining two operating phases of the power grid, maintaining the operating state of the three-phase inverter and reducing the waste of photovoltaic power generation resources.

[0048] In some embodiments, the remaining two phases include a first target phase and a second target phase. Obtaining the phase sequence detection information of the remaining two phases in the power grid may include: The phase of the first target phase is delayed by 90 degrees to establish the first virtual phase; Obtain the integral value of the voltage product of the first virtual phase and the second target phase over one power frequency cycle; The phase sequence of the remaining two phases in the power grid is determined based on the sign of the integral value.

[0049] In this embodiment, the remaining two operating phases of the power grid include a first target phase and a second target phase. Based on the first target phase, a first virtual phase with a phase delay of 90 degrees is established. Then, the integral value of the voltage product of the first virtual phase and the second target phase within one power frequency cycle is calculated. Based on the positive or negative sign of the integral value, the phase sequence of the remaining two phases in the power grid is determined to be positive or negative.

[0050] In actual implementation, a filter can be constructed to control the phase delay of the filter at the grid frequency to be 90 degrees, thereby establishing a first virtual phase corresponding to the first target. The phase of the first virtual phase is delayed by 90 degrees compared to the phase of the first target, and the amplitude of the first virtual phase is the same as that of the first target phase.

[0051] Among them, the transfer function of the filter It can be designed as ,in, Represents complex frequency. , Indicates the frequency of the power grid.

[0052] When the power grid frequency is 50Hz, the transfer function Bode Diagram as Figure 17 As shown, Frequency represents the frequency, Magnitude represents the amplitude, and Phase represents the phase. The Bode plot is used to represent the amplitude-frequency characteristics (the change of amplitude with frequency) and phase-frequency characteristics (the change of phase shift with frequency) of the system.

[0053] like Figure 11 As shown, in a three-phase AC power grid, the phase sequence is positive. The voltage expressions for phases L1, L2, and L3 are as follows:

[0054] in, This represents the voltage of phase L1. This represents the voltage of phase L2. This represents the voltage of phase L3. Indicates the amplitude of the phase voltage. Indicates time, It represents angular frequency.

[0055] In actual implementation, angular frequency With frequency and power frequency cycle The relationship is .

[0056] In this embodiment, such as Figure 15 As shown, a virtual phase with a 90-degree phase delay is established based on phase L1. .

[0057] virtual phase The integral value of the product of the voltage of phase L2 and phase L2 over one power frequency cycle. as follows:

[0058] virtual phase The integral value of the product of the voltage of phase L3 and the voltage of phase L3 over one power frequency cycle. as follows:

[0059] in, Indicates virtual phase The voltage.

[0060] In this embodiment, when the phase sequence relationship is positive, the virtual phase... The integral of the product of the voltage of phase L2 and phase L2 over one power frequency cycle is positive, indicating a virtual phase. The integral of the product of the voltage of phase L3 and phase L3 over one power frequency cycle is negative. The two integral values ​​have different signs, and the phase order can be determined based on the sign of the integral values.

[0061] Similarly, such as Figure 12 As shown, in a three-phase AC power grid, the phase sequence is negative. The voltage expressions for phases L1, L2, and L3 are as follows:

[0062] in, This represents the voltage of phase L1. This represents the voltage of phase L2. This represents the voltage of phase L3. Indicates the amplitude of the phase voltage. Indicates time, It represents angular frequency.

[0063] Using phase L1 as a reference, a virtual phase with a 90-degree phase delay is established. virtual phase The voltage expression is .

[0064] virtual phase The integral value of the product of the voltage of phase L2 and phase L2 over one power frequency cycle. as follows:

[0065] virtual phase The integral value of the product of the voltage of phase L3 and the voltage of phase L3 over one power frequency cycle. as follows:

[0066] in, Indicates virtual phase The voltage.

[0067] In this embodiment, when the phase sequence relationship is negative, the virtual phase... The integral of the product of the voltage of phase L2 and phase L2 over one power frequency cycle is negative, indicating a virtual phase. The integral of the product of the voltage of phase L3 and phase L3 over one power frequency cycle is positive. The two integral values ​​have different signs, and the phase order can be determined based on the sign of the integral values.

[0068] In some embodiments, determining the phase sequence of the remaining two phases in the power grid based on the sign of the integral value includes: If the sign of the integral value is positive, the phase sequence of the remaining two phases in the power grid is determined to be positive.

[0069] like Figure 13As shown, in a two-phase AC power grid, the phase sequence is positive. The voltage expressions for phases L1 and L2 are as follows:

[0070] Using phase L1 as a reference, a virtual phase with a 90-degree phase delay is established. virtual phase The voltage expression is .

[0071] virtual phase The integral value of the product of the voltage of phase L2 and phase L2 over one power frequency cycle. as follows:

[0072] In this embodiment, If the value is positive, the phase sequence of phases L1 and L2 is positive.

[0073] In other embodiments, determining the phase sequence of the remaining two phases in the power grid based on the sign of the integral value includes: If the sign of the integral value is negative, the phase sequence of the remaining two phases in the power grid is determined to be negative.

[0074] like Figure 14 As shown, in a two-phase AC power grid, the phase sequence is positive. The voltage expressions for phases L1 and L2 are as follows:

[0075] like Figure 16 As shown, a virtual phase with a 90-degree phase delay is established based on phase L1. virtual phase The voltage expression is .

[0076] virtual phase The integral value of the product of the voltage of phase L2 and phase L2 over one power frequency cycle. as follows:

[0077] In this embodiment, If the value is negative, the phase sequence of phases L1 and L2 will be negative.

[0078] It is understandable that when a single phase is lost in the power grid, and the phase sequence of the remaining two operating phases is different, the phase angles of the remaining two operating phases will also be different.

[0079] For example, such as Figure 18 As shown, the phase sequence of phases L1 and L2 is positive, and the phase angle of phase L2 is... The calculation formula is as follows:

[0080] in, This is the phase angle of phase L1.

[0081] For example, such as Figure 19 As shown, the phase sequence of phases L1 and L2 is negative, and the phase angle of phase L2 is... The calculation formula is as follows:

[0082] in, This is the phase angle of phase L1.

[0083] In some embodiments, the remaining two phases include a first target phase and a second target phase. Determining the phase angle detection information of the remaining two phases based on the phase sequence detection information may include: Phase-locked to the first target phase to obtain the phase angle of the first target phase; Based on the phase angle and phase sequence detection information of the first target phase, the phase angle of the second target phase is determined.

[0084] The phase angles of the first target phase and the second target phase differ by 120 degrees.

[0085] In this embodiment, based on the three-phase voltage of the power grid, phase-locked calculation is performed in a fixed coordinate system. The first target phase is phase-locked to obtain the phase angle of the first target phase. Then, based on the 120-degree phase difference between the phase angles of the first and second target phases and the phase order of the first and second target phases, the phase angle of the second target phase is calculated.

[0086] For example, the phase angle of the first target phase L1 Phase angle of the second target phase L2 When the phase sequence of phases L1 and L2 is positive, When the phase sequence of phases L1 and L2 is negative, .

[0087] In this embodiment, by establishing a virtual phase corresponding to one of the remaining two phases, the integral value of the product of the voltage of the virtual phase and the other phase of the remaining two phases over one power frequency cycle is calculated. Based on the sign of the integral value, the phase sequence of the remaining two phases is determined. After obtaining the phase sequence, one phase of the remaining two phases is phase-locked, and the phase angle of the other phase is calculated based on the phase sequence. This allows for a simple and quick determination of the phase sequence and phase angle of the remaining two operating phases, enabling the three-phase inverter to be quickly switched from three-phase operating mode to two-phase operating mode, maintaining the continuity of three-phase inverter operation, and reducing the waste of photovoltaic power generation resources.

[0088] In some embodiments, the control method for a three-phase inverter may further include: When the three-phase inverter is operating in three-phase mode, in response to the loss of two phases in the power grid, the three-phase inverter is controlled to operate in single-phase mode.

[0089] In this embodiment, the three-phase inverter monitors the operation of the power grid in real time. When it detects that two phases of the power grid have lost power and only one phase of the power grid is still running, it controls the three-phase inverter to switch from three-phase operation mode to single-phase operation mode. The three-phase inverter can output one phase of AC power to maintain the operation of the three-phase inverter and reduce the waste of photovoltaic power generation resources.

[0090] In some embodiments, the three-phase inverter is connected to the power grid via a three-phase grid-connected / off-grid switching device.

[0091] Understandably, three-phase grid-connected and off-grid switching devices are used in three-phase AC power grids to enable grid-connected and off-grid operation of three-phase inverters. The number of phases in the three-phase grid-connected and off-grid switching device is the same as the number of phases in the three-phase inverter.

[0092] like Figure 7 As shown, the inverter port of the three-phase grid-connected switching device is connected to the three phases of the photovoltaic-storage inverter, the grid port of the three-phase grid-connected switching device is connected to the three phases of the power grid, and the load port of the three-phase grid-connected switching device is connected to the load.

[0093] In this embodiment, the load can be powered by the photovoltaic-storage inverter and / or the power grid. The three-phase grid-connected switching device establishes an electrical connection between the three-phase inverter and the power grid, and the three-phase inverter operates in grid-connected mode. The three-phase grid-connected switching device disconnects the electrical connection between the three-phase inverter and the power grid, and the three-phase inverter operates in off-grid mode.

[0094] When the L1 phase of the grid loses power, the three-phase parallel-to-off-grid switching device can connect to the remaining two phases of the grid, L2 and L3.

[0095] In some embodiments, the control method for a three-phase inverter may further include: When the three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, in response to a fault in the remaining phase of the grid, the three-phase grid-connected / off-grid switching device is controlled to disconnect the three-phase inverter from the grid and control the three-phase inverter to operate in off-grid mode.

[0096] It is understandable that if a three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, it indicates that the power grid has experienced a single-phase or two-phase loss, and the three-phase grid-connected / off-grid switching device still maintains the connection between the three-phase inverter and the power grid, that is, the three-phase inverter is operating in grid-connected mode.

[0097] In this embodiment, when the three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, if the three-phase inverter detects a fault in the remaining two phases or one phase of the grid, it controls the three-phase grid-connected / off-grid switching device to disconnect the three-phase inverter from the grid and controls the three-phase inverter to operate in off-grid mode. The local power supply is kept stable by disconnecting the three-phase inverter from the grid. At this time, the load can be powered by the energy storage device 520 or the photovoltaic power generation device 510.

[0098] In actual operation, the three-phase inverter operates in two-phase grid-connected mode or single-phase grid-connected mode. In response to a fault in the remaining phase of the grid, the switching devices corresponding to each phase in the three-phase grid-connected switching device can be controlled to disconnect, and the three-phase inverter disconnects from the grid.

[0099] In some embodiments, after the grid-connected switching device disconnects from the grid, the control method for the three-phase inverter may further include: When the remaining phases are restored to power, the output of the three-phase inverter is controlled based on the operating parameters of the remaining phases of the power grid. With the operating parameters of the three-phase inverter and the remaining phases of the grid synchronized, the three-phase grid-connected switching device is controlled to establish the connection between the three-phase inverter and the grid, and the three-phase inverter is controlled to operate in grid-connected mode.

[0100] In this embodiment, the remaining phases of the grid are restored to power supply. The three-phase inverter detects the operating parameters (frequency, phase, and amplitude) of the remaining phases of the grid and performs synchronization control to make the output voltage of the three-phase inverter have the same frequency, phase, and amplitude as the voltage of the remaining phases of the grid, thereby synchronizing the operating parameters of the three-phase inverter and the remaining phases of the grid.

[0101] When the operating parameters of the three-phase inverter and the grid are synchronized, the control of the three-phase grid-connected switching device establishes the connection between the three-phase inverter and the grid. It can control the closing of the switching devices corresponding to each phase in the three-phase grid-connected switching device, control the three-phase inverter to operate in grid-connected mode, and can restore to two-phase grid-connected mode or single-phase grid-connected mode.

[0102] For example, when a three-phase inverter is operating in two-phase grid-connected mode, if the three-phase inverter detects a fault in the remaining L1 and L2 phases of the grid, it controls the three-phase grid-connected / off-grid switching device to disconnect the three-phase inverter from the grid, and the three-phase inverter operates off-grid. When the L1 and L2 phases are restored to power supply, the output of the three-phase inverter can be controlled according to the frequency, phase, and amplitude of the L1 and L2 phases. When the operating parameters of the three-phase inverter and the grid are synchronized, the three-phase grid-connected / off-grid switching device is controlled to establish the connection between the three-phase inverter and the grid, and the three-phase inverter switches back to two-phase grid-connected mode.

[0103] For example, when a three-phase inverter is operating in single-phase grid-connected mode, if the three-phase inverter detects a fault in the remaining L1 phase of the grid, it controls the three-phase grid-connected / off-grid switching device to disconnect the three-phase inverter from the grid, and the three-phase inverter operates off-grid. When the L1 phase resumes power supply, the output of the three-phase inverter can be controlled according to the frequency, phase, and amplitude of the L1 phase. When the operating parameters of the three-phase inverter and the grid are synchronized, the three-phase grid-connected / off-grid switching device is controlled to establish the connection between the three-phase inverter and the grid, and the three-phase inverter switches back to single-phase grid-connected mode.

[0104] Understandably, when the remaining phases of the grid that have failed are restored to power, the output of the three-phase inverter is controlled according to the operating parameters of the remaining phases of the grid. When the frequency, phase and amplitude of the three-phase inverter and the grid are synchronized, the three-phase inverter is connected to the grid through the three-phase grid-connected switching device to reduce the adverse effects of the inrush current and achieve smooth grid connection of the three-phase inverter.

[0105] In some embodiments, the control method for a three-phase inverter may further include: When the three-phase inverter is operating in three-phase mode, in response to a phase loss in the power grid, the power conversion circuit in the three-phase inverter corresponding to the phase loss in the power grid stops working.

[0106] It is understandable that a three-phase inverter includes three power conversion circuits, which work together to generate three-phase alternating current.

[0107] In this embodiment, the three-phase inverter operates in three-phase mode. When a phase is lost in the power grid, the power conversion circuit in the three-phase inverter corresponding to the phase loss stops working. That is, the power conversion circuit corresponding to the phase loss no longer outputs voltage to ensure safety and avoid external electric shock.

[0108] For example, such as Figure 8 As shown, the three-phase four-wire inverter is connected to the power grid. The input of the inverter circuit (L1 phase, L2 phase and L3 phase correspond to three power conversion circuits respectively) is DC voltage input, and the output is connected to the power grid through a relay. When L1 phase is missing, the power conversion circuit corresponding to L1 is controlled to stop working.

[0109] In this embodiment, the three-phase inverter operates in a two-phase working mode or a single-phase working mode. That is, when the three-phase inverter is running with a phase loss, each operating phase in the three-phase inverter uses an independent control mode.

[0110] The control method for a three-phase inverter provided in this application can be executed by a control device for the three-phase inverter. This application uses the example of a control device for the three-phase inverter executing the control method to illustrate the control device for the three-phase inverter provided in this application.

[0111] This application also provides a control device for a three-phase inverter, which is connected to the power grid.

[0112] like Figure 3 As shown, the control device for this three-phase inverter includes: The first processing module 310 is used to obtain the phase sequence detection information of the remaining two phases in the power grid in response to a single phase loss when the three-phase inverter is operating in three-phase working mode. The second processing module 320 is used to determine the phase angle detection information of the remaining two phases based on the phase sequence detection information. The third processing module 330 is used to control the three-phase inverter to operate in two-phase mode based on the phase angle detection information.

[0113] According to the control device of the three-phase inverter provided in the embodiments of this application, when a single-phase power failure occurs in the power grid, the phase sequence detection information of the remaining two phases is obtained, the phase angle detection information of the remaining two phases is determined, and the three-phase inverter is controlled to switch from the three-phase working mode to the two-phase working mode, so that the two-phase output of the three-phase inverter matches the remaining two operating phases of the power grid, maintaining the operating state of the three-phase inverter and reducing the waste of photovoltaic power generation resources.

[0114] In some embodiments, the remaining two phases include a first target phase and a second target phase. The first processing module 310 is used to acquire phase sequence detection information of the remaining two phases in the power grid, including: The phase of the first target phase is delayed by 90 degrees to establish the first virtual phase; Obtain the integral value of the voltage product of the first virtual phase and the second target phase over one power frequency cycle; The phase sequence of the remaining two phases in the power grid is determined based on the sign of the integral value.

[0115] In some embodiments, the first processing module 310 is configured to determine the phase sequence of the remaining two phases in the power grid based on the sign of the integral value, including: If the sign of the integral value is positive, the phase sequence of the remaining two phases in the power grid is determined to be positive. Alternatively, if the sign of the integral value is negative, the phase sequence of the remaining two phases in the power grid is determined to be negative.

[0116] In some embodiments, the remaining two phases include a first target phase and a second target phase. The second processing module 320 is used to determine the phase angle detection information of the remaining two phases based on the phase sequence detection information, including: Phase-locked to the first target phase to obtain the phase angle of the first target phase; Based on the phase angle and phase sequence detection information of the first target phase, the phase angle of the second target phase is determined, and the phase angles of the first target phase and the second target phase differ by 120 degrees.

[0117] In some embodiments, the third processing module 330 is further configured to: When the three-phase inverter is operating in three-phase mode, in response to the loss of two phases in the power grid, the three-phase inverter is controlled to operate in single-phase mode.

[0118] In some embodiments, the three-phase inverter is connected to the power grid via a three-phase grid-connected switching device, and the third processing module 330 is further configured to: When the three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, in response to a fault in the remaining phase of the grid, the three-phase grid-connected / off-grid switching device is controlled to disconnect the three-phase inverter from the grid and control the three-phase inverter to operate in off-grid mode.

[0119] In some embodiments, after the grid-connected switching device disconnects from the power grid, the third processing module 330 is further configured to: When the remaining phases are restored to power, the output of the three-phase inverter is controlled based on the operating parameters of the remaining phases of the power grid. With the operating parameters of the three-phase inverter and the remaining phases of the grid synchronized, the three-phase grid-connected switching device is controlled to establish the connection between the three-phase inverter and the grid, and the three-phase inverter is controlled to operate in grid-connected mode.

[0120] In some embodiments, the third processing module 330 is further configured to: When the three-phase inverter is operating in three-phase mode, in response to a phase loss in the power grid, the power conversion circuit in the three-phase inverter corresponding to the phase loss in the power grid stops working.

[0121] The control device for the three-phase inverter in this application embodiment can be an electronic device or a component in an electronic device, such as an integrated circuit or a chip.

[0122] The control device for the three-phase inverter provided in this application embodiment can realize the various processes implemented in the above-described three-phase inverter control method embodiment. To avoid repetition, it will not be described again here.

[0123] This application embodiment also provides a three-phase inverter, which is connected to the power grid and includes the control device for the three-phase inverter as described above.

[0124] According to the three-phase inverter provided in the embodiments of this application, when a single-phase power failure occurs in the power grid, the phase sequence detection information of the remaining two phases is obtained, the phase angle detection information of the remaining two phases is determined, and the three-phase inverter is controlled to switch from three-phase working mode to two-phase working mode, so that the two-phase output of the three-phase inverter matches the remaining two operating phases of the power grid, maintaining the operating state of the three-phase inverter and reducing the waste of photovoltaic power generation resources.

[0125] This application also provides a control method for a two-phase inverter.

[0126] The control method for a two-phase inverter provided in this application embodiment can be executed by a two-phase inverter or a functional module or functional entity in a two-phase inverter that can implement the control method for the two-phase inverter.

[0127] The two-phase inverter is connected to the power grid, with its AC terminal connected to the power grid and its DC terminal connected to the photovoltaic power generation device 510 and / or energy storage device 520.

[0128] It should be noted that a two-phase inverter can output AC power in two phases. The power grid connected to a two-phase inverter can be either a three-phase AC system or a two-phase AC system. For two-phase inverters connected to a three-phase AC system, the phase that is not connected to the power grid can be preset.

[0129] For example, the power grid includes phases L1, L2, and L3. A two-phase inverter is connected to phases L2 and L3, while the two-phase inverter is not connected to phase L1 of the power grid. The two-phase inverter outputs two-phase AC power.

[0130] The phase difference between phases L2 and L3 is 120 degrees.

[0131] For two-phase AC power grids, such as Figure 10 As shown, the power grid includes phase L2 and phase L3, with a phase difference of 180 degrees between phase L2 and phase L3.

[0132] It should be noted that for a two-phase AC power grid, there is no positive or negative phase sequence between the two operating phases.

[0133] This application provides a control method for a two-phase inverter. The two-phase inverter is connected to a three-phase AC power grid. It can detect the phase sequence and phase angle of the two operating phases and control the two-phase output of the two-phase inverter to match the two operating phases of the power grid. In the event of a single-phase power failure in the power grid, the inverter can maintain its operating state and reduce the waste of photovoltaic power generation resources.

[0134] like Figure 2 As shown, the control method of the three-phase inverter includes steps 210, 220, 230 and 240.

[0135] Step 210: Obtain the phase sequence detection information of two phases in the power grid.

[0136] In this step, the two phases in the power grid can be the first target phase and the second target phase. Obtaining the phase sequence detection information of the two phases in the power grid can include: The phase of the first target phase is delayed by 90 degrees to establish the first virtual phase; Obtain the integral value of the voltage product of the first virtual phase and the second target phase over one power frequency cycle; The phase sequence of two phases in the power grid is determined based on the sign of the integral value.

[0137] In some embodiments, determining the phase sequence of two phases in the power grid based on the sign of the integral value includes: If the sign of the integral value is positive, the phase sequence of two phases in the power grid is determined to be positive.

[0138] In other embodiments, determining the phase sequence of two phases in the power grid based on the sign of the integral value includes: When the sign of the integral value is negative, the phase sequence of two phases in the power grid is determined to be negative.

[0139] Step 220: Based on the phase sequence detection information, determine the phase angle detection information of the two phases.

[0140] In this step, the phase angle of the two operating phases is calculated based on the phase sequence of the two operating phases in the power grid, and the phase angle detection information of the two phases is obtained.

[0141] In some embodiments, the two operating phases in the power grid can be a first target phase and a second target phase. Determining the phase angle detection information of the two phases based on phase sequence detection information may include: Phase-locked to the first target phase to obtain the phase angle of the first target phase; Based on the phase angle and phase sequence detection information of the first target phase, the phase angle of the second target phase is determined.

[0142] The phase angles of the first target phase and the second target phase differ by 120 degrees.

[0143] Step 230: Based on the phase angle detection information, control the two-phase inverter to operate in two-phase working mode.

[0144] In this step, based on the phase angle detection information of the two-phase operating phases, the phase sequence and phase angle of the two-phase operating phases are determined, and the two-phase inverter is controlled to operate in two-phase working mode, and the two-phase inverter outputs AC power in two phases.

[0145] Step 240: In response to a single-phase loss in the power grid, control the two-phase inverter to operate in single-phase mode.

[0146] In this step, the two-phase inverter monitors the operation of the power grid in real time. If it detects that one of the two phases of the power grid has lost power, i.e., a single phase loss has occurred in the power grid, it identifies the remaining operating phase of the power grid and controls the two-phase inverter to operate in single-phase mode.

[0147] In this embodiment, the two-phase inverter first detects the phase sequence of the two-phase operating phases of the power grid, then determines the phase angle of the two-phase operating phases based on the phase sequence. Based on the phase sequence and phase angle of the two-phase operating phases, the two-phase output of the two-phase inverter is controlled. When a single phase is lost in the power grid, the two-phase inverter is controlled to operate in single-phase mode. This can maintain the operating state of the two-phase inverter in the event of a single-phase power failure in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0148] It should be noted that the process of detecting the two-phase phase sequence and phase angle in the control method of a two-phase inverter is the same as that in the control method of a three-phase inverter. To avoid repetition, it will not be described again here.

[0149] According to the control method of the two-phase inverter in this application, by acquiring the phase sequence detection information and phase angle detection information of the two phases of the power grid, the two-phase output of the two-phase inverter is controlled according to the phase sequence and phase angle of the two-phase operating phases. When a single phase loss occurs in the power grid, the two-phase inverter is controlled to operate in a single-phase working mode. This can maintain the operating state of the two-phase inverter in the event of a single phase power failure in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0150] The control method for a two-phase inverter provided in this application can be executed by a control device for the two-phase inverter. This application uses the example of a control device for the two-phase inverter executing the control method to illustrate the control device for the two-phase inverter provided in this application.

[0151] This application also provides a control device for a two-phase inverter, which is connected to the power grid.

[0152] like Figure 4 As shown, the control device for this two-phase inverter includes: The fourth processing module 410 is used to acquire phase sequence detection information of two phases in the power grid; The fifth processing module 420 is used to determine the phase angle detection information of the two phases based on the phase sequence detection information; The sixth processing module 430 is used to control the two-phase inverter to operate in two-phase mode based on the phase angle detection information; The seventh processing module 440 is used to control the two-phase inverter to operate in single-phase mode in response to a single-phase loss in the power grid.

[0153] According to the control device of the two-phase inverter provided in the embodiments of this application, by acquiring the phase sequence detection information and phase angle detection information of the two phases of the power grid, the two-phase output of the two-phase inverter is controlled according to the phase sequence and phase angle of the two-phase operating phases. When a single phase loss occurs in the power grid, the two-phase inverter is controlled to operate in a single-phase working mode. In the event of a single phase power failure in the power grid, the operating state of the two-phase inverter can be maintained, reducing the waste of photovoltaic power generation resources.

[0154] The control device for the two-phase inverter in this embodiment can be an electronic device or a component in an electronic device, such as an integrated circuit or a chip.

[0155] The control device for the two-phase inverter provided in this application embodiment can realize the various processes implemented in the above-described control method embodiment for the two-phase inverter. To avoid repetition, these processes will not be described again here.

[0156] This application also provides a two-phase inverter, which is connected to the power grid and includes the control device for the two-phase inverter as described above.

[0157] According to the two-phase inverter provided in the embodiments of this application, by acquiring the phase sequence detection information and phase angle detection information of the two phases of the power grid, the two-phase output of the two-phase inverter is controlled according to the phase sequence and phase angle of the two-phase operating phases. When a single phase loss occurs in the power grid, the two-phase inverter is controlled to operate in a single-phase working mode. This can maintain the operating state of the two-phase inverter in the event of a single phase power failure in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0158] This application also provides a power supply system.

[0159] like Figure 5 As shown, the power supply system includes a power supply device 530, a photovoltaic power generation device 510, and an energy storage device 520. The AC terminal of the power supply device 530 is used to connect to the power grid, and the DC terminal of the power supply device 530 is connected to the photovoltaic power generation device 510 and the energy storage device 520.

[0160] The power supply equipment 530 is either a three-phase inverter as described above, or a two-phase inverter as described above.

[0161] According to the power supply system provided in the embodiments of this application, by acquiring phase sequence detection information and phase angle detection information, the output of the power supply equipment 530 is controlled, which can maintain the operation of the power supply equipment 530 in the event of a single-phase power failure in the power grid, thereby reducing the waste of photovoltaic power generation resources.

[0162] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0163] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0164] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0165] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0166] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method for a three-phase inverter, characterized in that, The three-phase inverter is connected to the power grid, and the method includes: When the three-phase inverter is operating in three-phase mode, in response to a single-phase loss in the power grid, the phase sequence detection information of the remaining two phases in the power grid is obtained; Based on the phase sequence detection information, the phase angle detection information of the remaining two phases is determined; Based on the phase angle detection information, the three-phase inverter is controlled to operate in two-phase mode.

2. The control method for a three-phase inverter according to claim 1, characterized in that, The remaining two phases include a first target phase and a second target phase. Obtaining the phase sequence detection information of the remaining two phases in the power grid includes: The phase of the first target phase is delayed by 90 degrees to establish the first virtual phase; Obtain the integral value of the voltage product of the first virtual phase and the second target phase over one power frequency cycle; Based on the sign of the integral value, the phase sequence of the remaining two phases in the power grid is determined.

3. The control method for a three-phase inverter according to claim 2, characterized in that, Determining the phase sequence of the remaining two phases in the power grid based on the sign of the integral value includes: If the sign of the integral value is positive, the phase sequence of the remaining two phases in the power grid is determined to be positive. Alternatively, if the sign of the integral value is negative, the phase sequence of the remaining two phases in the power grid is determined to be negative.

4. The control method for a three-phase inverter according to claim 1, characterized in that, The remaining two phases include a first target phase and a second target phase. Determining the phase angle detection information of the remaining two phases based on the phase sequence detection information includes: Phase-locked to the first target phase, and the phase angle of the first target phase is obtained; Based on the phase angle of the first target phase and the phase sequence detection information, the phase angle of the second target phase is determined, and the phase angles of the first target phase and the second target phase differ by 120 degrees.

5. The control method for a three-phase inverter according to claim 1, characterized in that, The method further includes: When the three-phase inverter is operating in three-phase mode, in response to the occurrence of two-phase loss in the power grid, the three-phase inverter is controlled to operate in single-phase mode.

6. The control method for a three-phase inverter according to any one of claims 1-5, characterized in that, The three-phase inverter is connected to the power grid via a three-phase grid-connected switching device, and the method further includes: When the three-phase inverter is operating in two-phase grid-connected mode or single-phase grid-connected mode, in response to a fault in the remaining phase of the grid, the three-phase grid-connected / off-grid switching device is controlled to disconnect the three-phase inverter from the grid and control the three-phase inverter to operate in off-grid mode.

7. The control method for a three-phase inverter according to claim 6, characterized in that, After the grid-connected switching device is disconnected from the power grid, the method further includes: When the remaining phases are restored to power, the output of the three-phase inverter is controlled based on the operating parameters of the remaining phases of the power grid. When the operating parameters of the three-phase inverter and the remaining phase of the power grid are synchronized, the three-phase grid-connected switching device is controlled to establish the connection between the three-phase inverter and the power grid, and the three-phase inverter is controlled to operate in grid-connected mode.

8. The control method for a three-phase inverter according to any one of claims 1-5, characterized in that, The method further includes: When the three-phase inverter is operating in the three-phase working mode, in response to a phase loss in the power grid, the power conversion circuit in the three-phase inverter corresponding to the phase loss in the power grid is controlled to stop working.

9. A control method for a two-phase inverter, characterized in that, The two-phase inverter is connected to the power grid, and the method includes: Obtain phase sequence detection information for two phases in the power grid; Based on the phase sequence detection information, the phase angle detection information of the two phases is determined; Based on the phase angle detection information, the two-phase inverter is controlled to operate in a two-phase working mode; In response to a single-phase loss in the power grid, the two-phase inverter is controlled to operate in single-phase mode.

10. A control device for a three-phase inverter, characterized in that, The three-phase inverter is connected to the power grid, and the control device includes: The first processing module is used to obtain the phase sequence detection information of the remaining two phases in the power grid in response to a single phase loss when the three-phase inverter is operating in three-phase mode. The second processing module is used to determine the phase angle detection information of the remaining two phases based on the phase sequence detection information; The third processing module is used to control the three-phase inverter to operate in two-phase mode based on the phase angle detection information.

11. A three-phase inverter, characterized in that, The three-phase inverter is connected to the power grid, and the three-phase inverter includes the control device for the three-phase inverter as described in claim 10.

12. A control device for a two-phase inverter, characterized in that, The two-phase inverter is connected to the power grid, and the control device includes: The fourth processing module is used to acquire phase sequence detection information of two phases in the power grid; The fifth processing module is used to determine the phase angle detection information of the two phases based on the phase sequence detection information; The sixth processing module is used to control the two-phase inverter to operate in a two-phase working mode based on the phase angle detection information; The seventh processing module is used to control the two-phase inverter to operate in single-phase mode in response to a single-phase loss in the power grid.

13. A two-phase inverter, characterized in that, The two-phase inverter is connected to the power grid, and the two-phase inverter includes the control device for the two-phase inverter as described in claim 12.

14. A power supply system, characterized in that, include: The equipment includes a power supply device, a photovoltaic power generation device, and an energy storage device. The AC terminal of the power supply device is used to connect to the power grid, and the DC terminal of the power supply device is connected to the photovoltaic power generation device and the energy storage device. The power supply equipment is a three-phase inverter as described in claim 11, or a two-phase inverter as described in claim 13.

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