Uninterruptible power supply bypass power failure detection method, control device and system

Abstract

The present invention provides a method, control device, and system for detecting bypass power failures in an uninterruptible power supply (UPS). The method comprises: obtaining the bypass voltage of each phase of the UPS in the previous cycle when the UPS is in economy mode; wherein the phase of the bypass voltage at the start of each cycle of each phase is the same; determining the DC component of each phase's bypass voltage based on the bypass voltage of each phase; and determining a bypass power failure when the DC component of the bypass voltage of any phase exceeds a first preset threshold. By utilizing the characteristic of a motor generating reverse electromotive force, the DC component of the bypass voltage is detected. By determining that the DC component of the bypass voltage exceeds a certain threshold, a bypass abnormality is quickly determined, thereby avoiding inverter shutdown caused by untimely power supply mode switching.

Description

Technical Field

[0001] The present application belongs to the technical field of uninterruptible power supplies, and in particular relates to a method, a control device, and a system for detecting bypass power failure of an uninterruptible power supply. Background Art

[0002] With the rise of energy conservation and environmental protection concepts, and advancements in UPS (Uninterruptible Power Supply) technology, the UPS's ECO mode (economic operation mode) has become widely used in applications where power quality requirements are low but energy conservation is essential. In ECO mode, when the mains power quality is excellent, the UPS supplies power to the load via bypass mode, with the inverter in standby mode. When the mains voltage or frequency exceeds a certain range, the UPS switches to inverter power. Therefore, the key to reliable operation of the UPS's ECO mode is how to quickly detect mains power anomalies.

[0003] However, when the load is an electric motor, the reverse electromotive force generated by the motor causes the amplitude of the bypass voltage to drop very slowly, and it is impossible to quickly determine the bypass power failure by detecting that the bypass voltage amplitude and frequency are out of range. The energy generated by the reverse electromotive force of the motor is fed back to the DC bus of the UPS, causing the bus to overvoltage, thereby triggering the UPS bus overvoltage protection mechanism, the inverter shutdown, and affecting the power supply reliability of the UPS. Summary of the Invention

[0004] In view of this, the present invention provides a method, a control device and a system for detecting bypass power failure of an uninterruptible power supply, aiming to solve the problem of low power supply reliability of the prior art UPS.

[0005] A first aspect of an embodiment of the present invention provides a method for detecting bypass power failure of an uninterruptible power supply, comprising:

[0006] When the uninterruptible power supply is in an economic operation mode, obtaining the bypass voltage of each phase of the uninterruptible power supply in the previous cycle; wherein the phase of the bypass voltage of each phase at the start time of each cycle is the same;

[0007] determining a DC component of the bypass voltage of each phase based on the bypass voltage of each phase;

[0008] When the DC component of the bypass voltage of any phase exceeds a first preset threshold, it is determined that the bypass is powered off.

[0009] A second aspect of an embodiment of the present invention provides a method for detecting bypass power failure of an uninterruptible power supply, comprising:

[0010] an acquisition module, configured to acquire the bypass voltage of each phase of the uninterruptible power supply in the previous cycle when the uninterruptible power supply is in an economic operation mode; wherein the phase of the bypass voltage of each phase at the start time of each cycle is the same;

[0011] a determination module, configured to determine a DC component of a bypass voltage of each phase based on the bypass voltage of each phase;

[0012] The judgment module is used to judge that the bypass power is off when the DC component of the bypass voltage of any phase exceeds a first preset threshold.

[0013] A third aspect of an embodiment of the present invention provides a control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the uninterruptible power supply bypass power failure detection method described in the first aspect above are implemented.

[0014] A fourth aspect of the embodiments of the present invention provides an uninterruptible power supply system, comprising: an uninterruptible power supply, a zero-crossing detection circuit, a voltage sampling circuit, and the control device as described in the third aspect above; the control device is connected to the uninterruptible power supply;

[0015] The voltage sampling circuit is connected to the bypass of the uninterruptible power supply and is used to collect the three-phase bypass voltage in real time;

[0016] The zero-crossing detection circuit is connected to the bypass of the uninterruptible power supply and is used to report the zero-crossing moment to the control device when the bypass voltage of each phase passes through zero.

[0017] A fifth aspect of an embodiment of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the uninterruptible power supply bypass power failure detection method as described in the first aspect above.

[0018] The embodiments of the present invention provide a method, control device, and system for detecting bypass power failure in an uninterruptible power supply (UPS), including: obtaining the bypass voltage of each phase of the UPS in the previous cycle when the UPS is in economy mode; wherein the phase of the bypass voltage at the start of each cycle of each phase is the same; determining the DC component of each phase's bypass voltage based on the bypass voltage of each phase; and determining a bypass power failure when the DC component of the bypass voltage of any phase exceeds a first preset threshold. The method utilizes the characteristic of the motor generating reverse electromotive force to detect the DC component of the bypass voltage. By determining that the DC component of the bypass voltage exceeds a certain threshold, a bypass abnormality is quickly determined, thereby avoiding inverter shutdown caused by untimely power supply mode switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a flow chart of an implementation method for detecting bypass power failure of an uninterruptible power supply provided by an embodiment of the present invention;

[0021] Figure 2 1 is a schematic structural diagram of an uninterruptible power supply bypass power failure detection device provided by an embodiment of the present invention;

[0022] Figure 3 It is a structural diagram of an uninterruptible power supply system provided by an embodiment of the present invention;

[0023] Figure 4 It is a structural diagram of a control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0025] Figure 1 The present invention provides an embodiment of the uninterruptible power supply bypass power failure detection method.

[0026] like Figure 1 As shown, in some embodiments, a method for detecting bypass power failure of an uninterruptible power supply includes:

[0027] S201, when the uninterruptible power supply is in an economic operation mode, obtaining the bypass voltage of each phase of the uninterruptible power supply in the previous cycle; wherein the phase of the bypass voltage of each phase at the start time of each cycle is the same.

[0028] In this embodiment, the voltage of each phase can be divided into multiple cycles based on the starting time. It is necessary to ensure that the bypass voltage has the same phase at the starting time of each cycle. For example, if the starting time of each cycle of phase a is the moment when the bypass voltage crosses zero, then the starting time of each cycle of phases b and c must also be the moment when the bypass voltage crosses zero. If the starting time of each cycle of phase a is the moment when the bypass voltage reaches its peak, then the starting time of each cycle of phases b and c must also be the moment when the bypass voltage reaches its peak.

[0029] S202 : Determine a DC component of the bypass voltage of each phase based on the bypass voltage of each phase.

[0030] In this embodiment, when the AC power is normally supplied, the DC component of the bypass voltage is several hundred mV. When the AC power is cut off, the bypass voltage is actually the reverse electromotive force of the motor. At this time, the bypass voltage contains a large DC component. Therefore, by determining the DC component of the voltage, the abnormality of the bypass can be judged.

[0031] S203: When the DC component of the bypass voltage of any phase exceeds a first preset threshold, determine that the bypass is powered off.

[0032] In this embodiment, the first preset threshold may be manually set or calculated based on historical power-off data, which is not limited here.

[0033] In this embodiment, a method for detecting a bypass power failure in an uninterruptible power supply (UPS) includes: obtaining the bypass voltage of each phase of the UPS during the previous cycle when the UPS is in economy mode; wherein the bypass voltage of each phase has the same phase at the start of each cycle; determining the DC component of each phase's bypass voltage based on the bypass voltage of each phase; and determining a bypass power failure when the DC component of the bypass voltage of any phase exceeds a first preset threshold. By utilizing the characteristic of a motor generating reverse electromotive force, the DC component of the bypass voltage is detected. By determining that the DC component of the bypass voltage exceeds a certain threshold, a bypass abnormality is quickly determined, thereby avoiding inverter shutdown caused by untimely power supply mode switching.

[0034] In some embodiments, the starting time of each cycle of each phase is the zero-crossing time of the bypass voltage of that phase;

[0035] S202 may include:

[0036] For the bypass voltage of each phase, the average value of the bypass voltage of the phase in the previous cycle is calculated as the DC component of the bypass voltage of the phase.

[0037] In some embodiments, S203 may include:

[0038] If the DC component of the bypass voltage of any phase exceeds a first preset threshold and is not lower than a second preset threshold within a first preset time, it is determined that the bypass power is off; wherein the first preset time is at least one cycle.

[0039] In this embodiment, the first preset threshold value may be 5 V, and the second preset threshold value may be 2.5 V. If one cycle is 20 ms, taking phase a as an example, if the DC component of the bypass voltage of phase a is greater than 5 V and not less than 2.5 V within 20 ms, the bypass voltage is determined to be abnormal, and it is considered that the bypass power is off.

[0040] In this embodiment, the DC component of the bypass voltage of each phase can be compared with the first preset threshold value respectively, or the maximum value of the DC component of the bypass voltage of each phase can be determined first and then compared with the first preset threshold value, which is not limited here.

[0041] In this embodiment, by setting the first preset time length, frequent switching of the power supply mode due to accidental fluctuations of the mains power can be avoided, and misjudgment can be avoided while ensuring rapid confirmation of abnormalities.

[0042] In some embodiments, S203 may include:

[0043] If the DC component of the bypass voltage of any phase always exceeds the first preset threshold value within the second preset time period, it is determined that the bypass power is off.

[0044] In this embodiment, the second preset time duration may be at least one cycle. The first preset threshold may be 5V. If one cycle is 20ms, taking phase a as an example, if the DC component of the bypass voltage of phase a is greater than 5V within 20ms, the bypass voltage is determined to be abnormal and the bypass power is considered to be off.

[0045] In some embodiments, after S203, the method further includes:

[0046] Change the working mode of the uninterruptible power supply from economic operation mode to inverter power supply mode.

[0047] In some embodiments, the uninterruptible power supply bypass power failure detection method further includes: if the DC component of the bypass voltage of each phase does not exceed a first preset threshold, determining that the bypass is not powered off and maintaining the economic operation mode.

[0048] In this embodiment, the economic operation mode is that the bypass supplies power to the load, and the inverter power supply mode is that the main line supplies power to the load. By switching the power supply mode after quickly determining that the bypass power is off, the main line inverter shutdown can be avoided.

[0049] In some embodiments, S201 may include:

[0050] For each phase, the bypass voltage of the phase in the previous cycle is obtained at the zero-crossing point of the phase.

[0051] In some embodiments, if the DC component of the bypass voltage of any phase exceeds a first preset threshold and is not lower than a second preset threshold within a preset number of zero crossings, it is determined that the bypass is powered off.

[0052] In this embodiment, since the bypass voltage passes through two zero points in each cycle, the timing confirmation method can be changed to counting confirmation. Taking phase a as an example, when the DC component of the bypass voltage of phase a is greater than 5V and not less than 2.5V within the preset number of zero crossings, the bypass voltage is judged to be abnormal and it is considered that the bypass power is off at this time.

[0053] In some embodiments, the load of the uninterruptible power supply includes a motor.

[0054] In ECO mode, with bypass power supply and motor load, it is difficult to quickly detect bypass abnormalities using conventional detection of bypass voltage amplitude and frequency out of range. Generally, it takes 10 cycles to determine bypass abnormalities.

[0055] In this embodiment, the DC component of the bypass voltage is detected based on the characteristics of the motor's reverse electromotive force. By determining if the DC component of the bypass voltage exceeds a certain threshold, a bypass anomaly is detected, allowing for a rapid switch to the inverter power supply. After approximately one to two cycles, the bypass anomaly is detected, and the inverter power supply is switched back to normal.

[0056] 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 invention.

[0057] Figure 2 FIG is a schematic diagram of the structure of the uninterruptible power supply system provided by an embodiment of the present invention. Figure 2 As shown, the uninterruptible power supply system 2 includes: an uninterruptible power supply 21, a voltage sampling circuit 22, a zero-crossing detection circuit 23, and a control device 24; the control device 24 is connected to the uninterruptible power supply 21; the control device 24 is used to implement the uninterruptible power supply power failure detection method shown in any of the above embodiments.

[0058] The voltage sampling circuit 22 is connected to the bypass of the uninterruptible power supply 21 and is used to collect the three-phase bypass voltage in real time;

[0059] The zero-crossing detection circuit 23 is connected to the bypass of the uninterruptible power supply 21 and is used to report the zero-crossing moment to the control device 24 when the bypass voltage of each phase passes through zero.

[0060] In this embodiment, when the control device 24 receives the zero-crossing moment of a certain phase, it obtains the bypass voltage of the phase collected by the voltage sampling circuit 22 in the previous cycle of the zero-crossing moment to determine whether a power outage occurs.

[0061] In this embodiment, the control device 24 can be a single-chip microcomputer, an MCU, a desktop computer, a notebook computer, a PDA, or other computing devices, without limitation. The control device 24 can control the static switches in the main circuit and the bypass circuit to switch the operating mode of the uninterruptible power supply 21.

[0062] In some embodiments, the zero-crossing detection circuit 23 is replaced by a detection device such as a peak detection circuit to achieve the change of the starting time of the previous cycle.

[0063] Figure 3 FIG is a schematic diagram of the structure of the uninterruptible power supply bypass power failure detection device provided by an embodiment of the present invention. Figure 3 As shown, in some embodiments, the uninterruptible power supply bypass power failure detection device 3 includes:

[0064] An acquisition module 310 is configured to acquire the bypass voltage of each phase of the uninterruptible power supply in the previous cycle when the uninterruptible power supply is in the economy operation mode; wherein the bypass voltage of each phase at the start time of each cycle is the same in phase;

[0065] A determination module 320, configured to determine a DC component of the bypass voltage of each phase based on the bypass voltage of each phase;

[0066] The judgment module 330 is configured to judge that the bypass is powered off when the DC component of the bypass voltage of any phase exceeds a first preset threshold.

[0067] Optionally, the starting moment of each cycle of each phase is the zero-crossing moment of the bypass voltage of that phase;

[0068] The determination module 320 is specifically configured to:

[0069] For the bypass voltage of each phase, the average value of the bypass voltage of the phase in the previous cycle is calculated as the DC component of the bypass voltage of the phase.

[0070] Optionally, the judgment module 330 is specifically configured to:

[0071] If the DC component of the bypass voltage of any phase exceeds a first preset threshold and is not lower than a second preset threshold within a first preset time, it is determined that the bypass power is off; wherein the first preset time is at least one cycle.

[0072] Optionally, the judgment module 330 is specifically configured to:

[0073] If the DC component of the bypass voltage of any phase always exceeds the first preset threshold value within the second preset time period, it is determined that the bypass power is off.

[0074] Optionally, the uninterruptible power supply bypass power failure detection device 3 further includes a control module 340 .

[0075] The control module 340 is configured to change the working mode of the uninterruptible power supply from the economic operation mode to the inverter power supply mode after determining that the bypass power is off.

[0076] The control module 340 is further configured to determine that the bypass is not powered off and maintain the economic operation mode if the DC component of the bypass voltage of each phase does not exceed the first preset threshold.

[0077] Optionally, the acquisition module 310 is specifically configured to:

[0078] For each phase, obtain the bypass voltage of the phase in the previous cycle at the zero-crossing point of the phase;

[0079] Optionally, the uninterruptible power supply load includes a motor.

[0080] Optionally, the judgment module 330 is specifically configured to judge that the bypass is powered off when the DC component of the bypass voltage of any phase exceeds a first preset threshold and is not lower than a second preset threshold within a preset number of zero crossings.

[0081] The uninterruptible power supply power failure detection device provided in this embodiment can be used to execute the above method embodiment. Its implementation principle and technical effects are similar and will not be described in detail in this embodiment.

[0082] Figure 4 Schematic diagram of the structure of the control device provided by the embodiment of the present invention. Figure 4 As shown, an embodiment of the present invention provides a control device 4, which includes: a processor 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40. When the processor 40 executes the computer program 42, the steps in the above-mentioned embodiments of the uninterruptible power supply power failure detection method are implemented, such as Figure 1 Alternatively, when the processor 40 executes the computer program 42, the functions of each module / unit in the above-mentioned system embodiments are realized, for example Figure 3 Functions of modules 310 to 330 are shown.

[0083] Exemplarily, the computer program 42 may be divided into one or more modules / units, one or more of which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program 42 in the control device 4.

[0084] The control device 4 can be a single chip microcomputer, MCU, desktop computer, notebook, PDA and other computing devices. The terminal can include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that Figure 4It is only an example of the control device 4 and does not constitute a limitation on the control device 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0085] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0086] The memory 41 can be an internal storage unit of the control device 4, such as the hard disk or memory of the control device 4. The memory 41 can also be an external storage device of the control device 4, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. equipped on the control device 4. Furthermore, the memory 41 can include both the internal storage unit of the control device 4 and an external storage device. The memory 41 is used to store computer programs and other programs and data required by the terminal. The memory 41 can also be used to temporarily store data that has been output or is about to be output.

[0087] An embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned uninterruptible power supply power failure detection system embodiment are implemented.

[0088] A computer-readable storage medium stores a computer program 42, which includes program instructions. When executed by the processor 40, the program instructions implement all or part of the process of the method in the above-described embodiment. The computer program 42 can also be used to instruct related hardware to complete the process. The computer program 42 can be stored in a computer-readable storage medium. When executed by the processor 40, the computer program 42 can implement the steps of each of the above-described method embodiments. The computer program 42 includes computer program code, which can be in source code form, object code form, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal, and software distribution medium. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media does not include electric carrier signals and telecommunication signals.

[0089] The computer-readable storage medium may be an internal storage unit of the terminal in any of the aforementioned embodiments, such as a hard disk or memory of the terminal. The computer-readable storage medium may also be an external storage device of the terminal, such as a plug-in hard disk equipped on the terminal, a smart memory card (SMC), a secure digital (SD) card, a flash memory card, etc. Furthermore, the computer-readable storage medium may include both an internal storage unit of the terminal and an external storage device. The computer-readable storage medium is used to store computer programs and other programs and data required by the terminal. The computer-readable storage medium may also be used to temporarily store data that has been output or is about to be output.

[0090] 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 invention.

[0091] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0092] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0093] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0094] In the embodiments provided herein, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of modules or units is merely a logical functional division. In actual implementation, other division methods may be used, such as multiple units or components being combined or integrated into another system, or some features being ignored or not implemented. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interface, or the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0095] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0096] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0097] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by a computer program to instruct the relevant hardware. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of each of the above-mentioned method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media does not include electric carrier signals and telecommunication signals.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for detecting a bypass power failure of an uninterruptible power supply, characterized in that: The load connected to the uninterruptible power supply includes a motor; the method includes: When the uninterruptible power supply is in an economic operation mode, obtaining the bypass voltage of each phase of the uninterruptible power supply in the previous cycle; wherein the phase of the bypass voltage of each phase at the start time of each cycle is the same; wherein the economic operation mode is to supply power to the load by the bypass; determining a DC component of the bypass voltage of each phase based on the bypass voltage of each phase; When the DC component of the bypass voltage of any phase exceeds a first preset threshold, it is determined that the bypass is powered off.

2. The uninterruptible power supply bypass power failure detection method according to claim 1, characterized in that: The starting moment of each cycle of each phase is the zero-crossing moment of the bypass voltage of that phase; Determining the DC component of the bypass voltage of each phase based on the bypass voltage of each phase includes: For the bypass voltage of each phase, the average value of the bypass voltage of the phase in the previous cycle is calculated as the DC component of the bypass voltage of the phase.

3. The uninterruptible power supply bypass power failure detection method according to claim 1, characterized in that: When a DC component of a bypass voltage of any phase exceeds a first preset threshold, determining that a bypass power failure occurs includes: If the DC component of the bypass voltage of any phase exceeds a first preset threshold and is not lower than a second preset threshold within a first preset time, it is determined that the bypass power is off; wherein the first preset time is at least one cycle.

4. The uninterruptible power supply bypass power failure detection method according to claim 1, characterized in that: When a DC component of a bypass voltage of any phase exceeds a first preset threshold, determining that a bypass power failure occurs includes: If the DC component of the bypass voltage of any phase always exceeds the first preset threshold value within the second preset time period, it is determined that the bypass power is off.

5. The uninterruptible power supply bypass power failure detection method according to claim 1, characterized in that: After determining that the bypass is powered off, the following steps are also performed: Change the working mode of the uninterruptible power supply from the economic operation mode to the inverter power supply mode; in the inverter power supply mode, the main circuit supplies power to the load; The method further comprises: If the DC component of the bypass voltage of each phase does not exceed the first preset threshold, it is determined that the bypass is not powered off and the economic operation mode is maintained.

6. The uninterruptible power supply bypass power failure detection method according to claim 2, characterized in that: When the DC component of the bypass voltage of any phase exceeds a first preset threshold, determining that the bypass power is off includes: If the DC component of the bypass voltage of any phase exceeds the first preset threshold and is not lower than the second preset threshold within the preset number of zero crossings, it is determined that the bypass power is off.

7. The uninterruptible power supply bypass power failure detection method according to claim 1, characterized in that: The load of the uninterruptible power supply includes a motor.

8. A control device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the uninterruptible power supply bypass power failure detection method as described in any one of claims 1 to 7 are implemented.

9. An uninterruptible power supply system, characterized in that: include: An uninterruptible power supply, a zero-crossing detection circuit, a voltage sampling circuit, and a control device as claimed in claim 8; The control device is connected to the uninterruptible power supply; The voltage sampling circuit is connected to the bypass of the uninterruptible power supply and is used to collect the three-phase bypass voltage in real time; The zero-crossing detection circuit is connected to the bypass of the uninterruptible power supply and is used to report the zero-crossing moment to the control device when the bypass voltage of each phase passes through zero.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the uninterruptible power supply bypass power failure detection method as described in any one of claims 1 to 7 are implemented.

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