Open-phase detection method and device for three-phase power supply and frequency converter

Abstract

The invention relates to a three-phase power supply-oriented open-phase detection method and device and a frequency converter. The method comprises the following steps: acquiring a three-phase voltage synthesis vector of a three-phase power supply to be measured; obtaining a synthesis vector statistical value of the three-phase voltage synthesis vector in a preset time period, comparing the synthesis vector statistical value with a preset standard voltage synthesis result, and determining an open-phase threshold according to a comparison result and a preset comparison threshold; and when it is detected that the three-phase voltage synthesis vector at any moment is smaller than an open-phase threshold value, generating an early warning signal for the open-phase of the to-be-detected three-phase power supply. By adopting the method, the accuracy of phase loss detection of the three-phase power supply can be improved.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a phase loss detection method, device and inverter for a three-phase power supply. Background Art

[0002] Three-phase power supply is a common power supply method in industrial electricity. It consists of three phase lines and a neutral line. The three-phase power supply can provide a stable current output and is suitable for rated operation of high-power equipment. Modern elevator inverters are generally powered by three-phase power supply, and the car is driven by a permanent magnet synchronous motor. The permanent magnet synchronous motor under vector control is very dependent on the stable output of the inverter. If one phase of the three-phase power supply fails to supply power normally due to a fault or other reasons during the use of the elevator, and it is not discovered in time, it is very likely that the current on two phases of the three-phase input power line is too large, the heat is serious, the inverter output is abnormal, and even burns out.

[0003] Phase loss detection in the prior art is mainly hardware detection, wherein hardware detection relies on an additional detection circuit to detect the bus voltage to determine whether there is a phase loss problem. However, this method has the problems of high detection cost, single detection means and low detection accuracy.

[0004] Currently, no effective solution has been proposed for the problem of low efficiency and accuracy of phase loss detection of three-phase power supply in the prior art. Summary of the invention

[0005] Based on this, it is necessary to provide a phase loss detection method, device and inverter for a three-phase power supply to address the above technical problems.

[0006] In a first aspect, the present application provides a method for detecting a phase loss in a three-phase power supply. The method comprises:

[0007] Obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested;

[0008] Obtaining a synthetic vector statistic value of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold value based on the comparison result and a preset comparison threshold value;

[0009] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, an early warning signal for phase loss of the three-phase power supply to be tested is generated.

[0010] In one embodiment, when it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, a warning signal for the three-phase power supply to be tested is generated, including:

[0011] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, three power phase waveforms corresponding to the three power phases in the three-phase power supply to be tested are sampled respectively;

[0012] When it is detected that among all the power phase waveforms, there are two power phase waveforms whose wave peaks are smaller than a preset first recheck threshold, a warning signal for the three-phase power supply to be tested is generated.

[0013] In one embodiment, obtaining a first recheck threshold includes:

[0014] Obtaining voltage extreme values ​​corresponding to each power supply phase waveform in a preset re-inspection time period, and determining a maximum voltage extreme value among the voltage extreme values;

[0015] A first recheck threshold is determined based on the voltage extreme value maximum value.

[0016] In one embodiment, the maximum voltage extreme value is 1.35 times the first recheck threshold.

[0017] In one embodiment, obtaining a synthetic vector statistic of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic with a preset standard voltage synthesis result, and determining a phase loss threshold according to the comparison result and a preset comparison threshold, including:

[0018] Obtaining a maximum value of a composite vector of a three-phase voltage composite vector within a preset time period;

[0019] The phase loss threshold is determined according to the product of the ratio of the maximum value of the synthetic vector to the preset standard voltage synthetic vector and the preset comparison threshold.

[0020] In one of the embodiments, the preset comparison threshold is determined according to a variation range of a preset standard voltage synthesis vector in a phase loss condition.

[0021] In one embodiment, the method further comprises:

[0022] When it is not detected that there are two power phase waveforms in the power phase waveform whose peaks are smaller than the first re-check threshold, it is determined that there is no phase loss in the three-phase power supply to be tested.

[0023] In one of the embodiments, the power supply voltage of the three-phase power supply to be tested is in a fluctuating state.

[0024] In a second aspect, the present application also provides a phase loss detection device for a three-phase power supply. The device comprises:

[0025] An acquisition module, used for acquiring a three-phase voltage synthesis vector of a three-phase power supply to be tested;

[0026] A calculation module, used to obtain a synthetic vector statistic value of the three-phase voltage synthetic vector within a preset time period, compare the synthetic vector statistic value with a preset standard voltage synthesis result, and combine the comparison result with a preset comparison threshold to obtain a phase loss threshold;

[0027] The generating module is used to generate a warning signal for the phase loss of the three-phase power supply to be tested when it is detected that the three-phase voltage synthesis vector is less than the phase loss threshold at any time.

[0028] In a third aspect, the present application further provides a frequency converter, which is connected to a three-phase power supply to be tested, and includes the phase loss detection device for the three-phase power supply as described above.

[0029] In a fourth aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0030] Obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested;

[0031] Obtaining a synthetic vector statistic value of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold value based on the comparison result and a preset comparison threshold value;

[0032] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, an early warning signal for phase loss of the three-phase power supply to be tested is generated.

[0033] In a fifth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0034] Obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested;

[0035] Obtaining a synthetic vector statistic value of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold value based on the comparison result and a preset comparison threshold value;

[0036] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, an early warning signal for phase loss of the three-phase power supply to be tested is generated.

[0037] The above-mentioned method, device and frequency converter for phase loss detection of three-phase power supply first obtain the three-phase voltage synthesis vector of the three-phase power supply to be tested, and then obtain the synthesis vector statistics of the three-phase voltage synthesis vector within a preset time period, compare the synthesis vector statistics with the preset standard voltage synthesis result, and determine the phase loss threshold according to the comparison result and the preset comparison threshold; finally, when it is detected that the three-phase voltage synthesis vector is less than the phase loss threshold at any time, an early warning signal for the phase loss of the three-phase power supply to be tested is generated. The present application can effectively improve the accuracy of phase loss detection of three-phase power supply, avoid the problem of false alarm of phase loss detection fault caused by power supply voltage fluctuation, and effectively improve the accuracy of phase loss detection of three-phase power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of a flow chart of a phase loss detection method in one embodiment;

[0039] Figure 2 The waveform of the voltage at the front end of the rectifier bridge when one phase of the three-phase power supply voltage is missing in one embodiment;

[0040] Figure 3 is a waveform of a composite value of three-phase voltages under an ideal state in an embodiment;

[0041] Figure 4 The waveform of the synthetic wave when one phase of the three-phase input is missing in one embodiment;

[0042] Figure 5 is a structural block diagram of a phase loss detection device in an embodiment;

[0043] Figure 6 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] In one embodiment, Figure 1 As shown, a phase loss detection method for a three-phase power supply is provided, comprising the following steps:

[0046] Step S110, obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested.

[0047] Specifically, the above-mentioned three-phase power supply is a common power supply method in the field, consisting of three phase lines and one neutral line. The three-phase power supply can provide a stable current output and is suitable for rated operation of high-power equipment. In some preferred embodiments, the three-phase power supply to be tested in this application is a three-phase four-wire power supply. The three-phase voltage synthesis vector of the three-phase power supply to be tested is obtained, wherein the three-phase voltage synthesis vector is the synthesis value U of the three-phase line voltage d , assuming that the phase voltages of the three-phase power supply are Ur, Us, and Ut respectively, this embodiment provides a method for calculating the three-phase line voltage synthetic vector:

[0048]

[0049] Among them, Urs is the line voltage between the R phase and the S phase, Ust is the line voltage between the S phase and the T phase, and Utr is the line voltage between the T phase and the R phase.

[0050] In theory, if there is no phase loss in the three-phase power input, Ud is a constant value, such as 380 V. However, in actual applications, due to differences in regions and power equipment, the three-phase power supply voltage may fluctuate, resulting in the three-phase voltage composite vector Ud not being a stable value.

[0051] Step S120, obtaining a synthetic vector statistic value of the three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold according to the comparison result and a preset comparison threshold.

[0052] Specifically, the synthetic vector statistic of the three-phase voltage synthetic vector Ud is obtained within a preset time period, wherein the preset time period can be set by relevant technical personnel, such as 30ms, and the synthetic vector statistic can be set to statistical values ​​such as average value and maximum value. In some preferred embodiments, the synthetic vector statistic is the maximum value of the three-phase voltage synthetic vector within the preset time period.

[0053] Then, the synthetic vector statistics are further compared with the preset standard voltage synthesis result, wherein the standard voltage synthesis result can be set by relevant technical personnel, such as 380V. The comprehensive comparison result and the preset comparison threshold Ua0 are combined to obtain the phase loss threshold Uamax, wherein the comparison result can be the ratio between the synthetic vector statistics and the standard voltage synthesis result; the comprehensive comparison result and the comparison threshold Ua0 can be the product of the calculated comparison result and the comparison threshold Ua0, and the value of Ua0 can be preset by relevant technical personnel, and can be set to 300V in some preferred embodiments.

[0054] Step S130, when it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, a warning signal for phase loss of the three-phase power supply to be tested is generated.

[0055] Specifically, the three-phase voltage composite vector Ud of the three-phase power supply to be tested is monitored in real time. When it is detected that the three-phase voltage composite vector at any time is less than the above-mentioned phase loss threshold Uamax, the three-phase power supply to be tested is judged to be phase-lost, and an early warning signal for the phase loss of the three-phase power supply to be tested is generated. In practical applications, when the power supply voltage fluctuates, if the three-phase voltage composite vector Ud is directly compared with the preset threshold, it is easy to cause false fault alarms. However, through this application, the phase loss threshold is calculated and updated according to the actual situation based on the statistical value of the three-phase voltage composite vector, and then the three-phase voltage composite vector is compared with the phase loss threshold, which can effectively reduce the probability of false alarms and improve the accuracy of phase loss detection.

[0056] Through steps S110 to S130, the synthetic vector statistics of the three-phase voltage synthetic vector within a preset time period are calculated, and the synthetic vector statistics are compared with the preset standard voltage synthesis result, and the comparison result is combined with the preset comparison threshold to calculate the phase loss threshold, and then the three-phase voltage synthetic vector is compared according to the phase loss threshold, thereby effectively improving the accuracy of phase loss detection and reducing the probability of false alarm.

[0057] In some embodiments, obtaining a synthetic vector statistic of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic with a preset standard voltage synthesis result, and determining a phase loss threshold according to the comparison result and a preset comparison threshold, includes:

[0058] Obtaining a maximum value of a composite vector of a three-phase voltage composite vector within a preset time period;

[0059] The phase loss threshold is determined according to the product of the ratio of the maximum value of the synthetic vector to the preset standard voltage synthetic vector and the preset comparison threshold.

[0060] Specifically, in this embodiment, the phase loss threshold used for comparison with the three-phase voltage synthetic vector needs to be calculated in real time, so as to improve the accuracy of the three-phase power supply phase loss detection. Among them, in this embodiment, the synthetic vector statistics preferably adopts the synthetic vector maximum value Udmax. Further, the standard voltage synthesis result is mostly in the form of a vector. In summary, in this embodiment, the ratio of the synthetic vector maximum value Udmax to the standard voltage synthetic vector is first calculated, for example, Udmax / 380V is calculated. Then it is combined with a preset comparison threshold, which represents the threshold for comparing and judging whether there is a phase loss in the three-phase power supply when there is no fluctuation in the voltage amplitude, that is, when the voltage amplitude does not fluctuate, it is considered that there is a phase loss when it is less than the comparison threshold. The comparison threshold is combined with the ratio of the above-mentioned synthetic vector maximum value to the standard voltage synthetic vector to calculate the final phase loss threshold used for comparison with the three-phase voltage synthetic vector. This embodiment is not only applicable to the ideal state where the voltage amplitude does not fluctuate, but also applicable to the case where the voltage amplitude fluctuates, and a more accurate judgment result of whether the three-phase power supply is phase-lost can be obtained.

[0061] In some of the embodiments, the preset comparison threshold is determined according to a variation range of a preset standard voltage synthesis vector in a phase loss condition.

[0062] Specifically, when one phase is missing, the three-phase voltage composite vector will fluctuate within a fixed voltage range. In this embodiment, the comparison threshold is determined according to the variation range of the standard voltage composite vector when a phase is missing, so that a more accurate phase-missing threshold corresponding to the actual three-phase voltage composite vector can be obtained, thereby ensuring accurate alarm.

[0063] In some embodiments, the method further comprises:

[0064] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, three power phase waveforms corresponding to the three power phases in the three-phase power supply to be tested are sampled respectively;

[0065] When it is detected that among all the power phase waveforms, there are two power phase waveforms whose wave peaks are smaller than a preset first recheck threshold, a warning signal for the three-phase power supply to be tested is generated.

[0066] Specifically, in order to further improve the accuracy of detection, this embodiment also provides a re-test method. In practical applications, when one phase of the three-phase power supply voltage is missing, the waveform presents a periodic waveform with a higher peak and two relatively lower peaks, such as Figure 2 As shown, Figure 2It is the waveform of the voltage at the front end of the rectifier bridge when one phase of the three-phase power supply voltage is missing. Therefore, the waveform and peak value of the three-phase voltage can be detected. If it is detected that there is a high peak in one phase and a relatively low peak in two phases, an early warning signal for the phase loss of the three-phase power supply to be tested can be output. Among them, the judgment method for whether there is a relatively low peak in two phases includes that a re-check threshold can be preset. When it is detected that the peak of the two-phase voltage is less than the re-check threshold, it is judged that the two-phase peak is relatively low. In this embodiment, another method can also be used, that is, according to the actual voltage situation of the three-phase power supply to be tested, the above-mentioned first re-check threshold is calculated. When it is detected that the peak of the waveform of two power supply phases is less than the above-mentioned first re-check threshold, it is judged that the power supply is missing at this time, and the above-mentioned early warning signal is generated. Specifically, when it is detected that the three-phase voltage synthetic vector Ud is less than the phase loss threshold at any time, the alarm signal is not directly output, but the three power supply phase waveforms corresponding to the three power supply phases in the three-phase power supply to be tested are sampled respectively, that is, the waveforms of the three-phase line voltages Urs, Ust, and Utr are sampled respectively.

[0067] The three power phase waveforms are detected, and the maximum value of each phase in the preset recheck time period is first obtained, which are Ursmax, Ustmax, and Utrmax in sequence, wherein the recheck time period can preferably be set to 100ms. Then the maximum value Umax of the voltage extreme value of each phase is determined, and the first recheck threshold Ucomp is calculated based on the maximum value Umax of the voltage extreme value.

[0068] When it is detected that the peaks of two power phase waveforms among the three phases of the power supply to be tested are smaller than the first recheck threshold Ucomp, it is considered that there is a phase loss problem in the three-phase power supply to be tested, and an early warning signal for the three-phase power supply to be tested is generated.

[0069] This embodiment provides a re-test method, which can further improve the accuracy of phase loss detection.

[0070] In some embodiments, the method further comprises:

[0071] Obtaining voltage extreme values ​​corresponding to each power supply phase waveform in a preset re-inspection time period, and determining a maximum voltage extreme value among the voltage extreme values;

[0072] A first recheck threshold is determined based on the voltage extreme value maximum value.

[0073] Specifically, the voltage extreme values ​​corresponding to each power supply phase waveform in the preset recheck time period are obtained, and the maximum voltage extreme value among the above three voltage extreme values ​​is determined, which is Umax mentioned above. In practical applications, if there is no phase loss in the three-phase power supply to be tested, but the three-phase voltage synthesis vector Ud is detected to be less than the above phase loss threshold Uamax due to power supply fluctuations and other reasons, then when rechecking at this time, it will be detected that the voltage extreme values ​​of the three-phase voltage waveforms are not much different, that is, the first recheck threshold calculated based on the maximum voltage extreme value is less than the remaining two relatively small voltage extreme values. If it is detected that the peaks of the two power supply phase waveforms are less than the above first recheck threshold, it indicates that there is a phase loss in the above three-phase power supply to be tested, and an early warning signal is generated.

[0074] Furthermore, the first re-check threshold Ucomp is determined according to the maximum value of the voltage extreme value. In practical applications, the first re-check threshold Ucomp needs to be determined in real time according to the maximum value of the voltage extreme value detected. The calculation method of the first re-check threshold Ucomp is:

[0075] Ucomp=Umax / 1.35, wherein Umax is the maximum voltage extreme value mentioned above.

[0076] This embodiment provides a method for calculating a first re-check threshold value, by which it is possible to determine whether the three-phase voltage to be tested has a periodic waveform with one high peak and two relatively low peaks, thereby more accurately determining whether the three-phase power supply to be tested has a phase loss problem.

[0077] In some of the embodiments, the method further includes: the maximum value of the voltage extreme value is 1.35 times the first recheck threshold value.

[0078] In some embodiments, it may happen that the peaks of the two power supply phase waveforms are both greater than the first re-check threshold, which indicates that the three-phase power supply to be tested is working normally and there is no phase loss.

[0079] Through this application, the three-phase power supply to be tested can be further re-tested, effectively improving the accuracy of phase loss detection and avoiding false detection.

[0080] In some of the embodiments, under ideal conditions, that is, when there is no abnormal fluctuation in the power supply voltage of the three-phase power supply, the three-phase voltage synthesis vector Ud of the three-phase power supply to be tested should be a fixed value, and when the three-phase power supply to be tested lacks one phase, the above three-phase voltage synthesis vector Ud will be expressed as a waveform of a sine wave with a fixed period, and the period is determined by the three-phase power frequency. At this time, the three-phase voltage synthesis vector Ud can be compared with a preset threshold value. If it is detected that the three-phase voltage synthesis vector Ud is less than the preset threshold value, it can be determined that the power supply to be tested is missing a phase. However, in actual applications, due to differences in regions and electrical equipment, it is possible to cause fluctuations in the three-phase power supply voltage, resulting in the three-phase voltage synthesis vector Ud of the above power supply not being a stable value. At this time, when compared with the preset threshold value, it is possible that at a certain moment, the three-phase voltage synthesis vector Ud is less than the threshold value, and is thus considered to be missing a phase, which will lead to misjudgment. In summary, the method proposed in the present application can effectively avoid misjudgment caused by power supply voltage fluctuations.

[0081] The present application also provides a preferred embodiment of a phase loss detection method for a three-phase power supply.

[0082] Under ideal conditions, if there is no phase loss in the three-phase power input and the power supply voltage is stable, the three-phase voltage composite value of the three-phase power supply should be a fixed value. In practical applications, this composite value is mostly 380V. Figure 3 It is the waveform of the three-phase voltage composite value under an ideal state in an embodiment. When the power supply voltage fluctuation is not considered, the detection of the phase loss of the three-phase power supply can be directly performed by comparing the three-phase voltage composite value with a preset threshold value (preferably set to 340V). If it is detected that the three-phase voltage composite value is less than the preset threshold value, a phase loss warning is performed. However, in actual applications, the line voltage amplitude may fluctuate by nearly 20% around 380V. If it is compared with the preset threshold value when the power supply voltage fluctuates, when the line voltage of the three-phase input power supply is less than 340V, that is, the three-phase voltage composite value is less than 340V, then after comparing with the preset threshold value, a false phase loss will be directly reported, thereby wasting manpower and material resources for maintenance and bringing inconvenience to production and life.

[0083] The present application is preferably applied in the scenario where the three-phase power supply voltage fluctuates. First, the three-phase voltage synthetic vector Ud of the three-phase power supply to be tested is calculated, and the synthetic vector maximum value Udmax of the three-phase voltage synthetic vector Ud within a preset time period (such as 30ms) is obtained, and the ratio between the synthetic vector maximum value Udmax and the preset standard voltage (preferably 380V) synthetic result when there is no phase loss is calculated, and the ratio result is multiplied by the preset comparison threshold Ua0 to obtain the phase loss threshold Uamax. In summary, the calculation method of the phase loss threshold Uamax can be summarized as the following formula:

[0084]

[0085] Based on the above phase loss threshold Uamax, the three-phase power supply to be tested can be monitored in real time. If it is detected that the three-phase voltage synthesis vector Ud of the three-phase power supply is less than Uamax, it can be considered that the three-phase power supply to be tested is phase-lost, and an early warning signal is generated. Figure 4 Schematic diagram of the waveform when one phase of the three-phase input is missing in an embodiment. As can be seen from the figure, when the three-phase input line voltage is 380V and one phase of the three-phase input is missing, the waveform is a sine wave curve with a maximum amplitude of 380V.

[0086] Further, when the three-phase power supply to be tested may be detected to be missing phase by the above method, a re-check process is performed, firstly sampling the three power phases Urs, Ust, and Utr in the three-phase power supply to be tested, and determining the voltage extreme values ​​of the three power phases within a preset re-check time period (preferably 100ms), which are Ursmax, Ustmax, and Utrmax, respectively. The three voltage extreme values ​​are compared to obtain the maximum value thereof, that is, the maximum voltage extreme value. Since the voltage value of the high peak after the loss of one phase is √3 times the voltage value of the low peak, the first re-check threshold Ucomp can be calculated, and the first re-check threshold Ucomp is compared with the voltage extreme value. If the voltage extreme value is less than the first re-check threshold Ucomp, it is determined that there is a phase loss at this time, wherein the calculation method of the first re-check threshold Ucomp is as follows:

[0087] Ucomp=Umax / 1.35

[0088] If it is detected that the remaining two smaller voltage extreme values ​​are both smaller than the first re-check threshold value Ucomp, the number of low peaks is determined to be 2, and the phase loss detection is considered to be correct. At this time, an early warning signal for phase loss of the three-phase power supply to be tested is generated.

[0089] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0090] Based on the same inventive concept, the embodiment of the present application also provides a phase-loss detection device for implementing the above-mentioned phase-loss detection method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more embodiments of the phase-loss detection device provided below can refer to the limitations of the phase-loss detection method above, and will not be repeated here.

[0091] In one embodiment, Figure 5 As shown, a phase loss detection device is provided, including: an acquisition module 51, a calculation module 52 and a generation module 53, wherein:

[0092] An acquisition module 51 is used to acquire a three-phase voltage synthesis vector of a three-phase power supply to be tested;

[0093] The calculation module 52 is used to obtain the synthetic vector statistics of the three-phase voltage synthetic vector within a preset time period, compare the synthetic vector statistics with the preset standard voltage synthesis result, and combine the comparison result with the preset comparison threshold to obtain the phase loss threshold;

[0094] The generating module 53 is used to generate a warning signal for phase loss of the three-phase power supply to be tested when it is detected that the three-phase voltage synthesis vector is less than the phase loss threshold at any time.

[0095] Specifically, the acquisition module 51 acquires the three-phase voltage composite vector of the three-phase power supply to be tested, and sends the three-phase voltage composite vector to the calculation module 52. The calculation module 52 then calculates the composite vector statistics of the three-phase voltage composite vector within a preset time period, compares the composite vector statistics with the preset standard voltage synthesis result, and combines the comparison result with the preset comparison threshold to obtain a phase loss threshold, and sends the phase loss threshold to the generation module 53. When the generation module 53 detects that the three-phase voltage composite vector is less than the phase loss threshold at any time, it generates a warning signal for phase loss of the three-phase power supply to be tested.

[0096] Each module in the above-mentioned phase loss detection device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0097] Based on the same inventive concept, an embodiment of the present application further provides a frequency converter, which is connected to a three-phase power supply to be tested, and includes the phase loss detection device as described above.

[0098] In some preferred embodiments, the inverter may be an elevator inverter. Based on the above-mentioned phase loss detection device, the phase loss problem of the three-phase four-wire power supply input of the elevator inverter can be effectively detected, thereby realizing that the inverter can give timely alarm when the input voltage is phase-lost.

[0099] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 6 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data related to phase loss detection calculations. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a phase loss detection method is implemented.

[0100] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0101] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0102] Obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested;

[0103] Obtaining a synthetic vector statistic value of a three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold value based on the comparison result and a preset comparison threshold value;

[0104] When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, an early warning signal for phase loss of the three-phase power supply to be tested is generated.

[0105] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0106] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0107] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A phase loss detection method for a three-phase power supply, characterized in that: The method comprises: Obtaining a three-phase voltage synthesis vector of the three-phase power supply to be tested; Obtaining a synthetic vector statistic value of the three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and determining a phase loss threshold value according to the comparison result and a preset comparison threshold value; When it is detected that the three-phase voltage composite vector is smaller than the phase loss threshold at any time, an early warning signal for the phase loss of the three-phase power supply to be tested is generated.

2. The method according to claim 1, characterized in that When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, generating a warning signal for the three-phase power supply to be tested includes: When it is detected that the three-phase voltage composite vector is less than the phase loss threshold at any time, three power phase waveforms corresponding to the three power phases in the three-phase power supply to be tested are sampled respectively; When it is detected that among all the power phase waveforms, there are two power phase waveforms whose wave peaks are smaller than a preset first recheck threshold, the early warning signal for the three-phase power supply to be tested is generated.

3. The method according to claim 2, characterized in that The step of obtaining the first retest threshold value includes: Obtaining voltage extreme values ​​corresponding to each of the power supply phase waveforms in a preset recheck time period, and determining a maximum voltage extreme value among the voltage extreme values; The first recheck threshold is determined based on the voltage extreme value maximum value.

4. The method according to claim 3, characterized in that The maximum voltage extreme value is 1.35 times the first re-check threshold.

5. The method according to claim 1, characterized in that The obtaining of the synthetic vector statistics of the three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistics with a preset standard voltage synthesis result, and determining a phase loss threshold according to the comparison result and a preset comparison threshold, includes: Obtaining a maximum value of a composite vector of the three-phase voltage composite vector within a preset time period; The phase loss threshold is determined according to the product of the ratio of the maximum value of the synthetic vector to the preset standard voltage synthetic vector and the preset comparison threshold.

6. The method according to claim 5, characterized in that The preset comparison threshold is determined according to the variation range of the preset standard voltage synthesis vector in the phase loss condition.

7. A phase loss detection device for a three-phase power supply, characterized in that: The device comprises: An acquisition module, used for acquiring a three-phase voltage synthesis vector of a three-phase power supply to be tested; A calculation module, used for obtaining a synthetic vector statistic value of the three-phase voltage synthetic vector within a preset time period, comparing the synthetic vector statistic value with a preset standard voltage synthesis result, and combining the comparison result with a preset comparison threshold to obtain a phase loss threshold; A generating module is used to generate a warning signal for the phase loss of the three-phase power supply to be tested when it is detected that the three-phase voltage synthesis vector is less than the phase loss threshold at any time.

8. A frequency converter, characterized in that: The frequency converter is connected to a three-phase power supply to be tested, and the frequency converter includes the phase loss detection device as claimed in claim 7.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images