Reverse phase sequence detection method, system and storage medium for motor protector

Abstract

The present invention provides a reverse phase sequence detection method, system and storage medium for a motor protector. Based on a preset alternating current cycle frequency, a first sampling frequency is obtained to collect the voltage value of each phase voltage; based on the judgment logic of the zero-crossing timing, the zero-crossing moment of each phase voltage is obtained to calculate the first zero-crossing interval and the second zero-crossing interval; finally, whether the alternating current is a reverse phase sequence is judged based on the first zero-crossing interval and the second zero-crossing interval; the present invention does not require an external metering chip or complex hardware, avoids complex sequence component calculations, reduces the MCU computing burden, and achieves a balance between low cost, high response speed and multi-functional protection while ensuring detection accuracy, providing reliable technical support for the safe operation of the motor.

Description

Technical Field

[0001] The present invention relates to the field of motor protectors, and more particularly to a reverse phase sequence detection method, system and storage medium applied to motor protectors. Background Art

[0002] The stable operation of electric motors is highly dependent on a stable three-phase power supply, and the phase sequence of the three-phase power supply plays a decisive role in determining the motor's rotation direction and operating efficiency. Accurately detecting and determining the phase sequence of the three-phase power supply is crucial for ensuring safe motor operation and preventing equipment damage caused by incorrect phase sequences. Currently, there are three main methods for detecting reverse phase sequences: hardware circuit detection, sequence component algorithm detection, and metering chip detection.

[0003] Hardware circuit detection method: First, a hardware circuit is used to shape the three-phase signal to output a square wave signal. Then, a microcontroller unit (MCU) detects the timing of the three-phase zero crossings to determine the phase sequence. However, this method increases hardware cost, complicates circuit design, and makes subsequent maintenance more difficult.

[0004] Sequence component algorithm detection: Reverse phase-sequence faults are detected by calculating the sequence component. However, the algorithm is complex and consumes a significant amount of MCU computing time. This can degrade overall system performance in systems with high real-time requirements and multi-tasking.

[0005] Metering chip detection method: This method uses the reverse phase sequence detection function of the metering chip to determine the phase sequence. However, this method is slow and only applicable to electricity meters. It cannot be applied to motor protectors and does not meet the requirements of motor protectors for fast and accurate phase sequence detection.

[0006] Therefore, there is an urgent need for a low-cost, fast-running reverse phase sequence detection technology for motor protectors. Summary of the Invention

[0007] In view of the above problems, the purpose of the present invention is to provide a reverse phase sequence detection method, system, and storage medium for motor protectors. First, no external metering chip or complex hardware is required, relying solely on a three-phase AC detection circuit to measure phase voltages, thus controlling hardware costs. Second, a judgment logic based on the zero-crossing timing is used to determine the voltage phase sequence, avoiding complex sequence component calculations and reducing the computational burden on the MCU. Finally, through fault protection, logging, self-testing, and other methods, a closed-loop protection system is formed, significantly improving equipment safety and operation and maintenance efficiency. While ensuring detection accuracy, a balance is achieved between low cost, high response speed, and multi-functional protection, providing reliable technical support for the safe operation of motors.

[0008] A first aspect of the present invention provides a reverse phase sequence detection method for a motor protector, the method comprising:

[0009] Obtaining a first sampling frequency based on a preset alternating current cycle frequency;

[0010] obtaining first voltage information, second voltage information, and third voltage information according to the first sampling frequency;

[0011] Obtaining a first zero-crossing time, a second zero-crossing time, and a third zero-crossing time according to the first voltage information, the second voltage information, and the third voltage information;

[0012] Obtaining a first zero-crossing interval and a second zero-crossing interval according to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment;

[0013] Determining whether the first zero-crossing interval is greater than the second zero-crossing interval;

[0014] If so, it is a reverse phase sequence, triggering a warning operation.

[0015] In this solution, the first voltage information, the second voltage information, and the third voltage information are obtained according to the first sampling frequency, specifically:

[0016] triggering at least two conversion channels to start analog-to-digital conversion according to the first sampling frequency, with each conversion channel performing at least three conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value;

[0017] Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information according to the first analog-to-digital sampling value and the second analog-to-digital sampling value respectively;

[0018] Searching a preset voltage correspondence table according to the first analog-to-digital information and the second analog-to-digital information to obtain the first voltage information and the second voltage information respectively;

[0019] A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0020] This plan also includes:

[0021] Get the total number of sampling points;

[0022] Calculating a difference between the second zero-crossing time and the first zero-crossing time to obtain first difference information;

[0023] Determine whether the first difference information is less than 0;

[0024] If yes, then calculating the sum of the first difference information and the total number of sampling points, and setting a first zero-crossing interval;

[0025] If not, setting a first zero-crossing interval according to the first difference information;

[0026] Calculating a difference between the third zero-crossing time and the first zero-crossing time to obtain second difference information;

[0027] Determine whether the second difference information is less than 0;

[0028] If yes, then calculating the sum of the second difference information and the total number of sampling points, and setting a second zero-crossing interval;

[0029] If not, set the second zero-crossing interval according to the second difference information.

[0030] This plan also includes:

[0031] Within the same AC power cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0032] This plan also includes:

[0033] Within the same AC cycle;

[0034] If the voltage value of the phase voltage is negative, the flag information is set;

[0035] If the flag information is in a set state and the voltage value of the phase voltage is positive or equal to 0, the flag information is reset and the zero-crossing point moment of the corresponding phase voltage is set according to the current sampling point sequence number.

[0036] In this solution, the triggering warning operation is specifically:

[0037] Switch the power supply to the motor or issue a warning signal;

[0038] A fault log is generated according to the voltage value and zero-crossing time of each phase voltage, the first sampling frequency, and the warning time, and is stored in a non-volatile memory.

[0039] A second aspect of the present invention provides a reverse phase sequence detection system for a motor protector, including a reverse phase sequence detection method program for a motor protector. When the reverse phase sequence detection method program for a motor protector is executed by the processor, the following steps are implemented:

[0040] Obtaining a first sampling frequency based on a preset alternating current cycle frequency;

[0041] obtaining first voltage information, second voltage information, and third voltage information according to the first sampling frequency;

[0042] Obtaining a first zero-crossing time, a second zero-crossing time, and a third zero-crossing time according to the first voltage information, the second voltage information, and the third voltage information;

[0043] Obtaining a first zero-crossing interval and a second zero-crossing interval according to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment;

[0044] Determining whether the first zero-crossing interval is greater than the second zero-crossing interval;

[0045] If so, it is a reverse phase sequence, triggering a warning operation.

[0046] In this solution, the first voltage information, the second voltage information, and the third voltage information are obtained according to the first sampling frequency, specifically:

[0047] triggering at least two conversion channels to start analog-to-digital conversion according to the first sampling frequency, with each conversion channel performing at least three conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value;

[0048] Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information according to the first analog-to-digital sampling value and the second analog-to-digital sampling value respectively;

[0049] Searching a preset voltage correspondence table according to the first analog-to-digital information and the second analog-to-digital information to obtain the first voltage information and the second voltage information respectively;

[0050] A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0051] This plan also includes:

[0052] Get the total number of sampling points;

[0053] Calculating a difference between the second zero-crossing time and the first zero-crossing time to obtain first difference information;

[0054] Determine whether the first difference information is less than 0;

[0055] If yes, then calculating the sum of the first difference information and the total number of sampling points, and setting a first zero-crossing interval;

[0056] If not, setting a first zero-crossing interval according to the first difference information;

[0057] Calculating a difference between the third zero-crossing time and the first zero-crossing time to obtain second difference information;

[0058] Determine whether the second difference information is less than 0;

[0059] If yes, then calculating the sum of the second difference information and the total number of sampling points, and setting a second zero-crossing interval;

[0060] If not, set the second zero-crossing interval according to the second difference information.

[0061] The third aspect of the present invention provides a computer-readable storage medium, which includes a reverse phase sequence detection method program applied to a motor protector. When the reverse phase sequence detection method program applied to a motor protector is executed by a processor, the steps of the reverse phase sequence detection method applied to a motor protector as described in any one of the above items are implemented.

[0062] The present invention provides a reverse phase sequence detection method, system and storage medium for a motor protector. Based on a preset alternating current cycle frequency, a first sampling frequency is obtained to collect the voltage value of each phase voltage; based on the judgment logic of the zero-crossing timing, the zero-crossing moment of each phase voltage is obtained to calculate the first zero-crossing interval and the second zero-crossing interval; finally, whether the alternating current is a reverse phase sequence is judged based on the first zero-crossing interval and the second zero-crossing interval; the present invention does not require an external metering chip or complex hardware, avoids complex sequence component calculations, reduces the MCU computing burden, and achieves a balance between low cost, high response speed and multi-functional protection while ensuring detection accuracy, providing reliable technical support for the safe operation of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope.

[0064] Figure 1 A flow chart showing a method for detecting a reverse phase sequence of a motor protector according to the present invention is shown;

[0065] Figure 2 A flow chart for detecting the voltage value of each phase voltage provided by an embodiment of the present invention is shown;

[0066] Figure 3 FIG1 shows an execution flow chart of a zero-crossing point judgment logic provided by an embodiment of the present invention;

[0067] Figure 4 The block diagram of the reverse phase sequence detection system of the motor protector according to the present invention is shown. DETAILED DESCRIPTION

[0068] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0069] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined in this manner in the embodiments of the present invention.

[0070] The words "first", "second" and similar terms used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the existence of at least one. Similarly, words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The steps before or after the method of the embodiment of the present invention do not necessarily have to be performed in exact order. On the contrary, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0071] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0072] Figure 1 The flowchart of the reverse phase sequence detection method of the present invention applied to the motor protector is shown.

[0073] like Figure 1 As shown, the first aspect of the present invention discloses a reverse phase sequence detection method applied to a motor protector, the method comprising:

[0074] S102, obtaining a first sampling frequency based on a preset alternating current cycle frequency;

[0075] S104, obtaining first voltage information, second voltage information, and third voltage information according to the first sampling frequency;

[0076] S106, obtaining a first zero-crossing time, a second zero-crossing time, and a third zero-crossing time according to the first voltage information, the second voltage information, and the third voltage information;

[0077] S108, obtaining a first zero-crossing interval and a second zero-crossing interval according to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment;

[0078] S110, determining whether the first zero-crossing interval is greater than the second zero-crossing interval;

[0079] S112: If yes, it is a reverse phase sequence, triggering a warning operation.

[0080] It should be noted that the AC power cycle frequency is the frequency of the detected three-phase AC power; the first sampling frequency is the time period for triggering the voltage sampling operation; the first voltage information is the voltage value between phases AB (Uab); the second voltage information is the voltage value between phases BC (Ubc); the third voltage information is the voltage value between phases CA (Uca); the first zero-crossing moment is the sampling point number (UabCount) corresponding to the zero-crossing point of the voltage value Uab; the second zero-crossing moment is the sampling point number (UbcCount) corresponding to the zero-crossing point of the voltage value Ubc; the third zero-crossing moment is the sampling point number (UcaCount) corresponding to the zero-crossing point of the voltage value Uca; the first zero-crossing interval is the sampling point number interval (PcountAB) between the zero-crossing point of phase A and the zero-crossing point of phase B; the second zero-crossing interval is the sampling point number interval (PcountAC) between the zero-crossing point of phase A and the zero-crossing point of phase C.

[0081] In this embodiment, a reverse phase sequence detection process for a motor protector is provided. First, the phase voltage acquisition frequency is determined based on the frequency of the three-phase alternating current (AC) according to a preset total number of samples; the total number of samples refers to the number of phase voltage measurements within a single three-phase AC cycle. Second, based on preset zero-crossing determination logic, the zero-crossing moments of each phase voltage are determined based on the real-time detected voltage values. Then, based on preset sampling interval calculation logic, the sampling point sequence interval (PcountAB) between the zero-crossing moments of phase A and phase B, and the sampling point sequence interval (PcountAC) between the zero-crossing moments of phase A and phase C are determined based on the difference between the zero-crossing moments of each phase voltage. Finally, based on the magnitude relationship between the first zero-crossing interval and the second zero-crossing interval, whether the three-phase AC current has a reverse phase sequence is determined. If the first zero-crossing interval is greater than the second zero-crossing interval, the phase sequence is determined to be reverse, triggering a warning operation to improve motor operation safety. If the first zero-crossing interval is less than the second zero-crossing interval, the phase sequence is determined to be positive. This embodiment does not require additional hardware circuits to shape the three-phase AC power. It only needs to use Uab, Ubc and Uca to detect the reverse phase sequence based on the zero-crossing point judgment. Figure 2 A flow chart for detecting the voltage value of each phase voltage provided by an embodiment of the present invention is shown.

[0082] According to an embodiment of the present invention, Figure 2 As shown, the first voltage information, the second voltage information and the third voltage information are obtained according to the first sampling frequency, specifically:

[0083] S202: trigger at least two conversion channels to start analog-to-digital conversion according to the first sampling frequency, and each conversion channel performs at least three conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value;

[0084] S204, obtaining first analog-to-digital information and second analog-to-digital information based on the first analog-to-digital sampling value and the second analog-to-digital sampling value, respectively;

[0085] S206: Search a preset voltage correspondence table according to the first analog-to-digital information and the second analog-to-digital information to obtain the first voltage information and the second voltage information respectively;

[0086] S208: Calculate the difference between the second voltage information and the first voltage information to obtain third voltage information.

[0087] It should be noted that the first analog-to-digital sampling value is a real-time analog-to-digital sampling value between phases AB; the second analog-to-digital sampling value is a real-time analog-to-digital sampling value between phases BC; the first analog-to-digital information is the analog-to-digital value (ADab) corresponding to the voltage between phases AB; and the second analog-to-digital information is the analog-to-digital value (ADbc) corresponding to the voltage between phases BC.

[0088] In this embodiment, a phase voltage detection process is provided as follows: according to the first sampling frequency, a first analog-to-digital sampling value and a second analog-to-digital sampling value are obtained; according to the first analog-to-digital sampling value and the second analog-to-digital sampling value, first analog-to-digital information and second analog-to-digital information are obtained respectively; according to the first analog-to-digital information and the second analog-to-digital information, the first voltage information and the second voltage information are obtained respectively; the difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0089] As an embodiment, a real-time analog-to-digital sampling value between the AB phase and the real-time analog-to-digital sampling value between the BC phase are measured and obtained respectively by an analog-to-digital converter including at least two conversion channels; wherein the analog-to-digital converter is provided by an analog-to-digital conversion chip or an MCU. At each sampling frequency, each channel performs at least three conversion operations to obtain at least three analog-to-digital sampling values; the above-mentioned analog-to-digital sampling values ​​and historical mode sampling values ​​are subjected to preset data processing; wherein the data processing method includes but is not limited to Kalman filtering, Butterworth filtering, weighted average processing, etc., to obtain the analog value of the corresponding channel. Then, based on the first analog-to-digital information and the second analog-to-digital information, a preset AD voltage correspondence table is queried to obtain the first voltage information and the second voltage information, respectively. Finally, the difference between the second voltage information and the first voltage information is calculated to obtain the third voltage information.

[0090] Figure 3 The figure shows an execution flow chart of a zero-crossing point judgment logic provided by an embodiment of the present invention.

[0091] According to an embodiment of the present invention, Figure 3 As shown, it also includes:

[0092] S302, obtaining the total number of sampling points;

[0093] S304, calculating the difference between the second zero-crossing time and the first zero-crossing time to obtain first difference information;

[0094] S306, determining whether the first difference information is less than 0;

[0095] S308: If yes, calculate the sum of the first difference information and the total number of sampling points, and set a first zero-crossing interval;

[0096] S310, if not, setting a first zero-crossing interval according to the first difference information;

[0097] S312, calculating the difference between the third zero-crossing time and the first zero-crossing time to obtain second difference information;

[0098] S314, determining whether the second difference information is less than 0;

[0099] S316: If yes, calculate the sum of the second difference information and the total number of sampling points, and set a second zero-crossing interval;

[0100] S318: If not, set a second zero-crossing interval according to the second difference information.

[0101] It should be noted that the total number of sampling points is the number of first analog-to-digital information or second analog-to-digital information obtained within the same AC power cycle. In this embodiment, a zero-crossing judgment logic execution process is provided as follows: obtaining the total number of sampling points; calculating the difference between the second zero-crossing moment and the first zero-crossing moment to set the first zero-crossing interval; if the first zero-crossing interval is less than 0, updating the first zero-crossing interval based on the total number of sampling points; calculating the difference between the third zero-crossing moment and the first zero-crossing moment to set the second zero-crossing interval; if the second zero-crossing interval is less than 0, updating the second zero-crossing interval based on the total number of sampling points.

[0102] As an implementation method, the first zero-crossing interval satisfies the following relationship:

[0103]

[0104] As an implementation method, the second zero-crossing interval satisfies the following relationship:

[0105]

[0106] Where:

[0107] is the total number of sampling points;

[0108] is the first zero-crossing interval;

[0109] is the second zero-crossing interval;

[0110] is the first zero-crossing moment;

[0111] is the second zero-crossing moment;

[0112] It is the third zero-crossing moment.

[0113] According to an embodiment of the present invention, the further embodiment includes:

[0114] Within the same AC power cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0115] It should be noted that in this embodiment, a number of sampling points are generally set according to the frequency of the AC cycle and the rule of equally dividing the time points. To ensure the accuracy of obtaining the zero-crossing time, in actual applications, at least 64 sampling points are generally used to control the sampling frequency.

[0116] According to an embodiment of the present invention, the further embodiment includes:

[0117] Within the same AC cycle;

[0118] If the voltage value of the phase voltage is negative, the flag information is set;

[0119] If the flag information is in a set state and the voltage value of the phase voltage is positive or equal to 0, the flag information is reset and the zero-crossing point moment of the corresponding phase voltage is set according to the current sampling point sequence number.

[0120] It should be noted that in this embodiment, a zero-crossing detection logic is provided. When the phase voltage value is negative, a flag is set. When the flag is set and the phase voltage value is positive or equal to 0, the current sampling point is recorded as the zero-crossing moment, indicating the sampling time point when the phase voltage value changes from negative to positive.

[0121] According to an embodiment of the present invention, the triggering warning operation is specifically:

[0122] Switch the power supply to the motor or issue a warning signal;

[0123] A fault log is generated according to the voltage value and zero-crossing time of each phase voltage, the first sampling frequency, and the warning time, and is stored in a non-volatile memory.

[0124] It should be noted that when a reverse phase sequence is detected, protective actions are executed to ensure motor safety, including but not limited to switching the motor power supply or issuing a warning signal. Switching the motor power supply allows the motor to attempt to reset before checking the phase sequence, improving motor safety. The issuance of a warning signal, acting as a maintenance request, improves motor operational stability. Furthermore, a fault log is generated based on information such as the phase voltage values ​​and zero-crossing times, the first sampling frequency, and the warning time, and is stored in non-volatile memory for subsequent query and analysis.

[0125] It is worth mentioning that it also includes:

[0126] When the motor power supply is switched after the early warning operation is determined to be triggered;

[0127] Control the motor to access the backup power supply and enter energy-saving mode;

[0128] The control performs a self-test until the phase sequence is positive and switches to the main power supply.

[0129] It should be noted that when the motor power supply is switched after the warning is triggered, if a backup power source is available, it is connected to the backup power source and enters energy-saving mode to prevent the motor from running at high speed. At this time, the main power supply is continuously tested until the main power supply phase sequence is positive, at which point the switch is returned to the main power supply. The main power supply is then used to restore the motor's normal operation mode.

[0130] It is worth mentioning that it also includes:

[0131] When a warning signal is issued after a warning operation is determined to have been triggered;

[0132] Control the motor to enter protection mode and limit the motor starting or running;

[0133] The control performs a self-test until the phase sequence is positive and the motor restrictions are released.

[0134] It should be noted that when a warning signal is issued after a pre-warning operation is triggered, the motor is first controlled to enter protection mode, restricting its startup or operation to prevent it from operating under reverse phase sequence conditions and causing equipment damage. Furthermore, the power supply is continuously tested until the power phase sequence returns to a positive phase sequence, at which point the motor resumes normal operation.

[0135] It is worth mentioning that it also includes:

[0136] Sending the fault log to a fault processing neural network model to obtain maintenance suggestions;

[0137] Send a maintenance request based on the maintenance suggestion.

[0138] It should be noted that fault logs are sent to a preset fault processing neural network model to obtain corresponding maintenance suggestions. Based on the maintenance suggestions, corresponding maintenance requests are generated and sent to improve equipment maintenance efficiency and reduce maintenance labor costs.

[0139] Figure 4 The block diagram of the reverse phase sequence detection system of the motor protector according to the present invention is shown.

[0140] like Figure 4As shown, the second aspect of the present invention discloses a reverse phase sequence detection system 4 applied to a motor protector, comprising a memory 41 and a processor 42. The memory includes a reverse phase sequence detection method program applied to the motor protector. When the reverse phase sequence detection method program applied to the motor protector is executed by the processor, the following steps are implemented:

[0141] Obtaining a first sampling frequency based on a preset alternating current cycle frequency;

[0142] obtaining first voltage information, second voltage information, and third voltage information according to the first sampling frequency;

[0143] Obtaining a first zero-crossing time, a second zero-crossing time, and a third zero-crossing time according to the first voltage information, the second voltage information, and the third voltage information;

[0144] Obtaining a first zero-crossing interval and a second zero-crossing interval according to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment;

[0145] Determining whether the first zero-crossing interval is greater than the second zero-crossing interval;

[0146] If so, it is a reverse phase sequence, triggering a warning operation.

[0147] It should be noted that the AC power cycle frequency is the frequency of the detected three-phase AC power; the first sampling frequency is the time period for triggering the voltage sampling operation; the first voltage information is the voltage value between phases AB (Uab); the second voltage information is the voltage value between phases BC (Ubc); the third voltage information is the voltage value between phases CA (Uca); the first zero-crossing moment is the sampling point number (UabCount) corresponding to the zero-crossing point of the voltage value Uab; the second zero-crossing moment is the sampling point number (UbcCount) corresponding to the zero-crossing point of the voltage value Ubc; the third zero-crossing moment is the sampling point number (UcaCount) corresponding to the zero-crossing point of the voltage value Uca; the first zero-crossing interval is the sampling point number interval (PcountAB) between the zero-crossing point of phase A and the zero-crossing point of phase B; the second zero-crossing interval is the sampling point number interval (PcountAC) between the zero-crossing point of phase A and the zero-crossing point of phase C.

[0148] In this embodiment, a reverse phase sequence detection process for a motor protector is provided. First, the phase voltage acquisition frequency is determined based on the frequency of the three-phase alternating current (AC) according to a preset total number of samples; the total number of samples refers to the number of phase voltage measurements within a single three-phase AC cycle. Second, based on preset zero-crossing determination logic, the zero-crossing moments of each phase voltage are determined based on the real-time detected voltage values. Then, based on preset sampling interval calculation logic, the sampling point sequence interval (PcountAB) between the zero-crossing moments of phase A and phase B, and the sampling point sequence interval (PcountAC) between the zero-crossing moments of phase A and phase C are determined based on the difference between the zero-crossing moments of each phase voltage. Finally, based on the magnitude relationship between the first zero-crossing interval and the second zero-crossing interval, whether the three-phase AC current has a reverse phase sequence is determined. If the first zero-crossing interval is greater than the second zero-crossing interval, the phase sequence is determined to be reverse, triggering a warning operation to improve motor operation safety. If the first zero-crossing interval is less than the second zero-crossing interval, the phase sequence is determined to be positive. This embodiment does not require additional hardware circuits to shape the three-phase AC power. It only needs to use Uab, Ubc and Uca to detect the reverse phase sequence based on the zero-crossing point judgment.

[0149] According to an embodiment of the present invention, obtaining the first voltage information, the second voltage information, and the third voltage information according to the first sampling frequency is specifically as follows:

[0150] triggering at least two conversion channels to start analog-to-digital conversion according to the first sampling frequency, with each conversion channel performing at least three conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value;

[0151] Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information according to the first analog-to-digital sampling value and the second analog-to-digital sampling value respectively;

[0152] Searching a preset voltage correspondence table according to the first analog-to-digital information and the second analog-to-digital information to obtain the first voltage information and the second voltage information respectively;

[0153] A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0154] It should be noted that the first analog-to-digital sampling value is a real-time analog-to-digital sampling value between phases AB; the second analog-to-digital sampling value is a real-time analog-to-digital sampling value between phases BC; the first analog-to-digital information is the analog-to-digital value (ADab) corresponding to the voltage between phases AB; and the second analog-to-digital information is the analog-to-digital value (ADbc) corresponding to the voltage between phases BC.

[0155] In this embodiment, a phase voltage detection process is provided as follows: according to the first sampling frequency, a first analog-to-digital sampling value and a second analog-to-digital sampling value are obtained; according to the first analog-to-digital sampling value and the second analog-to-digital sampling value, first analog-to-digital information and second analog-to-digital information are obtained respectively; according to the first analog-to-digital information and the second analog-to-digital information, the first voltage information and the second voltage information are obtained respectively; the difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0156] As an embodiment, a real-time analog-to-digital sampling value between the AB phase and the real-time analog-to-digital sampling value between the BC phase are measured and obtained respectively by an analog-to-digital converter including at least two conversion channels; wherein the analog-to-digital converter is provided by an analog-to-digital conversion chip or an MCU. At each sampling frequency, each channel performs at least three conversion operations to obtain at least three analog-to-digital sampling values; the above-mentioned analog-to-digital sampling values ​​and historical mode sampling values ​​are subjected to preset data processing; wherein the data processing method includes but is not limited to Kalman filtering, Butterworth filtering, weighted average processing, etc., to obtain the analog value of the corresponding channel. Then, based on the first analog-to-digital information and the second analog-to-digital information, a preset AD voltage correspondence table is queried to obtain the first voltage information and the second voltage information, respectively. Finally, the difference between the second voltage information and the first voltage information is calculated to obtain the third voltage information.

[0157] According to an embodiment of the present invention, the further embodiment includes:

[0158] Get the total number of sampling points;

[0159] Calculating a difference between the second zero-crossing time and the first zero-crossing time to obtain first difference information;

[0160] Determine whether the first difference information is less than 0;

[0161] If yes, then calculating the sum of the first difference information and the total number of sampling points, and setting a first zero-crossing interval;

[0162] If not, setting a first zero-crossing interval according to the first difference information;

[0163] Calculating a difference between the third zero-crossing time and the first zero-crossing time to obtain second difference information;

[0164] Determine whether the second difference information is less than 0;

[0165] If yes, then calculating the sum of the second difference information and the total number of sampling points, and setting a second zero-crossing interval;

[0166] If not, set the second zero-crossing interval according to the second difference information.

[0167] It should be noted that the total number of sampling points is the number of first analog-to-digital information or second analog-to-digital information obtained within the same AC power cycle. In this embodiment, a zero-crossing judgment logic execution process is provided as follows: obtaining the total number of sampling points; calculating the difference between the second zero-crossing moment and the first zero-crossing moment to set the first zero-crossing interval; if the first zero-crossing interval is less than 0, updating the first zero-crossing interval based on the total number of sampling points; calculating the difference between the third zero-crossing moment and the first zero-crossing moment to set the second zero-crossing interval; if the second zero-crossing interval is less than 0, updating the second zero-crossing interval based on the total number of sampling points.

[0168] As an implementation method, the first zero-crossing interval satisfies the following relationship:

[0169]

[0170] As an implementation method, the second zero-crossing interval satisfies the following relationship:

[0171]

[0172] Where:

[0173] is the total number of sampling points;

[0174] is the first zero-crossing interval;

[0175] is the second zero-crossing interval;

[0176] is the first zero-crossing moment;

[0177] is the second zero-crossing moment;

[0178] It is the third zero-crossing moment.

[0179] According to an embodiment of the present invention, the further embodiment includes:

[0180] Within the same AC power cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0181] It should be noted that in this embodiment, a number of sampling points are generally set according to the frequency of the AC cycle and the rule of equally dividing the time points. To ensure the accuracy of obtaining the zero-crossing time, in actual applications, at least 64 sampling points are generally used to control the sampling frequency.

[0182] According to an embodiment of the present invention, the further embodiment includes:

[0183] Within the same AC cycle;

[0184] If the voltage value of the phase voltage is negative, the flag information is set;

[0185] If the flag information is in a set state and the voltage value of the phase voltage is positive or equal to 0, the flag information is reset and the zero-crossing point moment of the corresponding phase voltage is set according to the current sampling point sequence number.

[0186] It should be noted that in this embodiment, a zero-crossing detection logic is provided. When the phase voltage value is negative, a flag is set. When the flag is set and the phase voltage value is positive or equal to 0, the current sampling point is recorded as the zero-crossing moment, indicating the sampling time point when the phase voltage value changes from negative to positive.

[0187] According to an embodiment of the present invention, the triggering warning operation is specifically:

[0188] Switch the power supply to the motor or issue a warning signal;

[0189] A fault log is generated according to the voltage value and zero-crossing time of each phase voltage, the first sampling frequency, and the warning time, and is stored in a non-volatile memory.

[0190] It should be noted that when a reverse phase sequence is detected, protective actions are executed to ensure motor safety, including but not limited to switching the motor power supply or issuing a warning signal. Switching the motor power supply allows the motor to attempt to reset before checking the phase sequence, improving motor safety. The issuance of a warning signal, acting as a maintenance request, improves motor operational stability. Furthermore, a fault log is generated based on information such as the phase voltage values ​​and zero-crossing times, the first sampling frequency, and the warning time, and is stored in non-volatile memory for subsequent query and analysis.

[0191] It is worth mentioning that it also includes:

[0192] When the motor power supply is switched after the early warning operation is determined to be triggered;

[0193] Control the motor to access the backup power supply and enter energy-saving mode;

[0194] The control performs a self-test until the phase sequence is positive and switches to the main power supply.

[0195] It should be noted that when the motor power supply is switched after the warning is triggered, if a backup power source is available, it is connected to the backup power source and enters energy-saving mode to prevent the motor from running at high speed. At this time, the main power supply is continuously tested until the main power supply phase sequence is positive, at which point the switch is returned to the main power supply. The main power supply is then used to restore the motor's normal operation mode.

[0196] It is worth mentioning that it also includes:

[0197] When a warning signal is issued after a warning operation is determined to have been triggered;

[0198] Control the motor to enter protection mode and limit the motor starting or running;

[0199] The control performs a self-test until the phase sequence is positive and the motor restrictions are released.

[0200] It should be noted that when a warning signal is issued after a pre-warning operation is triggered, the motor is first controlled to enter protection mode, restricting its startup or operation to prevent it from operating under reverse phase sequence conditions and causing equipment damage. Furthermore, the power supply is continuously tested until the power phase sequence returns to a positive phase sequence, at which point the motor resumes normal operation.

[0201] It is worth mentioning that it also includes:

[0202] Sending the fault log to a fault processing neural network model to obtain maintenance suggestions;

[0203] Send a maintenance request based on the maintenance suggestion.

[0204] It should be noted that fault logs are sent to a preset fault processing neural network model to obtain corresponding maintenance suggestions. Based on the maintenance suggestions, corresponding maintenance requests are generated and sent to improve equipment maintenance efficiency and reduce maintenance labor costs.

[0205] The third aspect of the present invention provides a computer-readable storage medium, which includes a reverse phase sequence detection method program applied to a motor protector. When the reverse phase sequence detection method program applied to a motor protector is executed by a processor, the steps of the reverse phase sequence detection method applied to a motor protector as described in any one of the above items are implemented.

[0206] In summary, the present invention provides a reverse phase sequence detection method, system and storage medium for a motor protector. Based on a preset alternating current cycle frequency, a first sampling frequency is obtained to collect the voltage value of each phase voltage; based on the judgment logic of the zero-crossing timing, the zero-crossing moment of each phase voltage is obtained to calculate the first zero-crossing interval and the second zero-crossing interval; finally, whether the alternating current is a reverse phase sequence is judged according to the first zero-crossing interval and the second zero-crossing interval; the present invention does not require an external metering chip or complex hardware, avoids complex sequence component calculations, reduces the MCU computing burden, and achieves a balance between low cost, high response speed and multi-functional protection while ensuring detection accuracy, providing reliable technical support for the safe operation of the motor.

[0207] If the functions are implemented as software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0208] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A reverse phase sequence detection method for a motor protector, characterized in that: The method comprises: Obtaining a first sampling frequency based on a preset alternating current cycle frequency; triggering at least two conversion channels to start analog-to-digital conversion according to the first sampling frequency, with each conversion channel performing at least three conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value; Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information according to the first analog-to-digital sampling value and the second analog-to-digital sampling value respectively; Searching a preset voltage correspondence table according to the first analog-to-digital information and the second analog-to-digital information to obtain first voltage information and second voltage information respectively; calculating a difference between the second voltage information and the first voltage information to obtain third voltage information; Obtaining a first zero-crossing time, a second zero-crossing time, and a third zero-crossing time according to the first voltage information, the second voltage information, and the third voltage information; Obtaining a first zero-crossing interval and a second zero-crossing interval according to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment; Get the total number of sampling points; Calculating a difference between the second zero-crossing time and the first zero-crossing time to obtain first difference information; Determine whether the first difference information is less than 0; If yes, then calculating the sum of the first difference information and the total number of sampling points, and setting a first zero-crossing interval; If not, setting a first zero-crossing interval according to the first difference information; Calculating a difference between the third zero-crossing time and the first zero-crossing time to obtain second difference information; Determine whether the second difference information is less than 0; If yes, then calculating the sum of the second difference information and the total number of sampling points, and setting a second zero-crossing interval; If not, setting a second zero-crossing interval according to the second difference information; Also includes: In the same alternating current cycle, at least 64 sampling points are included, that is, the total number of sampling points is at least 64; Determining whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is a reverse phase sequence, triggering the early warning operation; The triggering warning operation is specifically: Switch the power supply to the motor or issue a warning signal; Generate a fault log based on the voltage value and zero-crossing time of each phase voltage, the first sampling frequency, and the warning time, and store it in a non-volatile memory; Also includes: When the motor power supply is switched after the early warning operation is determined to be triggered; Control the motor to access the backup power supply and enter energy-saving mode; The control performs a self-test until the phase sequence is positive and switches to the main power supply.

2. The reverse phase sequence detection method for a motor protector according to claim 1, characterized in that: Also includes: Within the same AC cycle; If the voltage value of the phase voltage is negative, the flag information is set; If the flag information is in a set state and the voltage value of the phase voltage is positive or equal to 0, the flag information is reset and the zero-crossing point moment of the corresponding phase voltage is set according to the current sampling point sequence number.

3. A reverse phase sequence detection system for a motor protector, characterized in that: The system includes a memory and a processor, wherein the memory includes a reverse phase sequence detection method program applied to a motor protector, and when the reverse phase sequence detection method program applied to a motor protector is executed by the processor, the steps of the reverse phase sequence detection method applied to a motor protector as described in any one of claims 1 to 2 are implemented.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer-readable storage medium includes a reverse phase sequence detection method program applied to a motor protector. When the reverse phase sequence detection method program applied to a motor protector is executed by a processor, the steps of the reverse phase sequence detection method applied to a motor protector as described in any one of claims 1 to 2 are implemented.

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