Inverse phase sequence detection method and system applied to motor protector and storage medium

Abstract

The invention provides an inverse phase sequence detection method and system applied to a motor protector and a storage medium, and the method comprises the steps: obtaining a first sampling frequency based on a preset alternating current cycle frequency, and collecting the voltage value of each phase voltage; based on the judgment logic of the zero-crossing time sequence, obtaining the zero-crossing time of each phase voltage for calculating a first zero-crossing interval and a second zero-crossing interval; and finally, according to the first zero crossing point interval and the second zero crossing point interval, judging whether the alternating current is in a reverse phase sequence. An external metering chip or complex hardware is not needed, complex sequence component calculation is avoided, the MCU operation burden is reduced, the balance of low cost, high response speed and multifunctional protection is achieved while the detection precision is guaranteed, and reliable technical support is provided for safe operation of the motor.

Description

Technical Field

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

[0002] The stable operation of a motor highly depends on a stable three-phase power supply, and the phase sequence of the three-phase power supply plays a decisive role in the rotation direction and operation efficiency of the motor. Accurately detecting and judging the phase sequence of the three-phase power supply is of great significance in ensuring the safe operation of the motor and avoiding equipment damage caused by incorrect phase sequence. Currently, there are mainly three reverse phase sequence detection methods: hardware circuit detection method, sequence component algorithm detection method, and metering chip detection method.

[0003] Hardware circuit detection method: First, use a hardware circuit to shape the three-phase signals and output square wave signals, and then detect the zero-crossing timing of the three phases through a microcontroller unit (MCU) to judge the phase sequence. However, this method increases the hardware cost, improves the complexity of circuit design, and increases the difficulty of later maintenance.

[0004] Sequence component algorithm detection method: Judge the reverse phase sequence fault by solving the sequence components. However, the complexity of the related algorithms is relatively high, and a large amount of MCU operation time is required. In a system with high real-time requirements and multi-task processing, it is easy to cause a reduction in the overall performance of the system.

[0005] Metering chip detection method: Judge the phase sequence by means of the reverse phase sequence detection function of the metering chip. However, this method has a slow detection speed and is only applicable to electric energy meters, and cannot be applied to motor protector products, and cannot meet the requirements of fast and accurate phase sequence detection for motor protectors.

[0006] Therefore, there is an urgent need for a reverse phase sequence detection technology for motor protectors with low cost and fast operation efficiency. 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 applied to motor protectors. First, there is no need for an external metering chip or complex hardware, and only rely on a three-phase alternating current detection circuit to measure the phase voltage, controlling the hardware cost; then, based on the judgment logic of the zero-crossing timing, the voltage phase sequence is obtained, avoiding complex sequence component calculations and reducing the MCU operation burden; finally, through fault protection, log recording, self-checking, etc., a closed-loop protection system is formed, greatly improving the safety and operation and maintenance efficiency of the equipment. While ensuring the detection accuracy, the balance of low cost, high response speed, and multi-functional protection is achieved, providing reliable technical support for the safe operation of the motor.

[0008] The first aspect of the present invention provides a reverse phase sequence detection method applied to a motor protector, and the method includes: Based on a preset AC power cycle frequency, obtain a first sampling frequency; According to the first sampling frequency, obtain first voltage information, second voltage information, and third voltage information; According to the first voltage information, the second voltage information, and the third voltage information, obtain a first zero-crossing moment, a second zero-crossing moment, and a third zero-crossing moment; According to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment, obtain a first zero-crossing interval and a second zero-crossing interval; Judge whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is a reverse phase sequence, and a warning operation is triggered.

[0009] In this solution, the obtaining of the first voltage information, the second voltage information, and the third voltage information according to the first sampling frequency is specifically: According to the first sampling frequency, trigger at least 2 conversion channels to start analog-to-digital conversion, and each conversion channel performs at least 3 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, respectively obtain 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; According to the first analog-to-digital information and the second analog-to-digital information, look up a preset voltage correspondence table to respectively obtain the first voltage information and the second voltage information; Calculate the difference between the second voltage information and the first voltage information to obtain third voltage information.

[0010] This solution further includes: Obtain the total number of sampling points; Calculate the difference between the second zero-crossing moment and the first zero-crossing moment to obtain first difference information; Judge whether the first difference information is less than 0; If so, calculate the sum of the first difference information and the total number of sampling points, and set the first zero-crossing interval; If not, set the first zero-crossing interval according to the first difference information; Calculate the difference between the third zero-crossing moment and the first zero-crossing moment to obtain second difference information; Judge whether the second difference information is less than 0; If so, calculate the sum of the second difference information and the total number of sampling points, and set the second zero-crossing interval; If not, set a second zero-crossing interval according to the second difference information.

[0011] This solution also includes: Within the same AC cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0012] This solution also includes: Within the same AC cycle; If the voltage value of the phase voltage is negative, set the flag information. If the flag information is in the set state and the voltage value of the phase voltage is positive or equal to 0, reset the flag information and set the zero-crossing moment of the corresponding phase voltage according to the current sampling point number.

[0013] In this solution, the triggering of the warning operation is specifically: Switch the motor power supply or send a warning signal; Generate a fault log based on the voltage values and zero-crossing moments of each phase voltage, the first sampling frequency, and the warning time, and store it in the non-volatile memory.

[0014] The second aspect of the present invention provides an inverse phase sequence detection system applied to a motor protector, including an inverse phase sequence detection method program applied to the motor protector. When the inverse phase sequence detection method program applied to the motor protector is executed by the processor, the following steps are implemented: Based on a preset AC cycle frequency, obtain a first sampling frequency; According to the first sampling frequency, obtain first voltage information, second voltage information, and third voltage information; According to the first voltage information, the second voltage information, and the third voltage information, obtain a first zero-crossing moment, a second zero-crossing moment, and a third zero-crossing moment; According to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment, obtain a first zero-crossing interval and a second zero-crossing interval; Judge whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is an inverse phase sequence, and trigger a warning operation.

[0015] In this solution, the obtaining of the first voltage information, the second voltage information, and the third voltage information according to the first sampling frequency is specifically: According to the first sampling frequency, trigger at least 2 conversion channels to start analog-to-digital conversion. Each conversion channel performs at least 3 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, first analog-to-digital information and second analog-to-digital information are obtained respectively according to the first analog-to-digital sampling value and the second analog-to-digital sampling value; Based on the first analog-to-digital information and the second analog-to-digital information, a preset voltage correspondence table is searched to obtain the first voltage information and the second voltage information respectively; The difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0016] In this solution, it further includes: Obtain the total number of sampling points; The difference between the second zero-crossing moment and the first zero-crossing moment is calculated to obtain first difference information; Judge whether the first difference information is less than 0; If so, calculate the sum of the first difference information and the total number of sampling points, and set the first zero-crossing interval; If not, set the first zero-crossing interval according to the first difference information; The difference between the third zero-crossing moment and the first zero-crossing moment is calculated to obtain second difference information; Judge whether the second difference information is less than 0; If so, calculate the sum of the second difference information and the total number of sampling points, and set the second zero-crossing interval; If not, set the second zero-crossing interval according to the second difference information.

[0017] A third aspect of the present invention provides a computer-readable storage medium, which includes a reverse phase sequence detection method program for a motor protector. When the reverse phase sequence detection method program for the motor protector is executed by a processor, the steps of the reverse phase sequence detection method for the motor protector as described in any one of the above are implemented.

[0018] The present invention provides a reverse phase sequence detection method, system and storage medium for a motor protector. Based on a preset AC power frequency, a first sampling frequency is obtained for collecting the voltage values of each phase voltage; based on the judgment logic of the zero-crossing time sequence, the zero-crossing moments of each phase voltage are obtained for calculating the first zero-crossing interval and the second zero-crossing interval; finally, whether the AC power is in 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 operation burden, and while ensuring the detection accuracy, achieves a balance of low cost, high response speed and multi-functional protection, providing reliable technical support for the safe operation of the motor. Description of the Drawings

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0020] Figure 1 Shows a flowchart of the reverse phase sequence detection method applied to a motor protector according to the present invention; Figure 2 Shows a flowchart for detecting the voltage values of each phase voltage provided by an embodiment of the present invention; Figure 3 Shows a flowchart for executing the zero-crossing judgment logic provided by an embodiment of the present invention; Figure 4 Shows a block diagram of the reverse phase sequence detection system applied to a motor protector according to the present invention. Detailed implementation manners

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] 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 of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless explicitly defined in the embodiments of the present invention.

[0023] The "first", "second" and similar terms used in the embodiments of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Terms such as "a", "an" or "the" do not denote a quantity limitation either, but mean that there is at least one. Similarly, terms such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. "Connection" or "connected" and similar terms are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The steps before or after the methods of the embodiments of the present invention do not necessarily have to be carried out precisely in order. On the contrary, they can be carried out in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or several steps can be removed from these processes.

[0024] In addition, in each embodiment of the present invention, each functional module can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0025] Figure 1 The flowchart of the reverse phase sequence detection method of the present invention applied to a motor protector is shown.

[0026] As Figure 1 shown, the first aspect of the present invention discloses a reverse phase sequence detection method applied to a motor protector, and the method includes: S102, obtaining a first sampling frequency based on a preset AC power frequency; S104, obtaining first voltage information, second voltage information, and third voltage information according to the first sampling frequency; S106, obtaining a first zero-crossing moment, a second zero-crossing moment, and a third zero-crossing moment according to the first voltage information, the second voltage information, and the third voltage information; 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; S110, determining whether the first zero-crossing interval is greater than the second zero-crossing interval; S112, if so, it is a reverse phase sequence, and a warning operation is triggered.

[0027] It should be noted that the AC power frequency is the frequency of the three-phase alternating current to be detected; the first sampling frequency is the time period for triggering the voltage sampling operation; the first voltage information is the voltage value (Uab) between the AB phases; the second voltage information is the voltage value (Ubc) between the BC phases; the third voltage information is the voltage value (Uca) between the CA phases; the first zero-crossing moment is the sampling point serial number (UabCount) corresponding to the zero-crossing of the voltage value of Uab; the second zero-crossing moment is the sampling point serial number (UbcCount) corresponding to the zero-crossing of the voltage value of Ubc; the third zero-crossing moment is the sampling point serial number (UcaCount) corresponding to the zero-crossing of the voltage value of Uca; the first zero-crossing interval is the sampling point serial number interval (PcountAB) between the zero-crossing of phase A and the zero-crossing of phase B; the second zero-crossing interval is the sampling point serial number interval (PcountAC) between the zero-crossing of phase A and the zero-crossing of phase C.

[0028] In this embodiment, an inverse phase sequence detection process applied to a motor protector is provided. First, according to the frequency of three-phase alternating current, the acquisition frequency of the phase voltage is determined according to a preset total number of samples; where the total number of samples refers to the number of times of measuring the phase voltage within the same cycle of three-phase alternating current. Secondly, based on a preset zero-crossing judgment logic, the zero-crossing moments of each phase voltage are obtained according to the voltage values detected in real time of each phase voltage. Then, based on a preset calculation logic of the sampling interval, according to the difference between the zero-crossing moments of each phase voltage, the sampling point sequence number interval (PcountAB) between the zero-crossing point of phase A and the zero-crossing point of phase B and the sampling point sequence number interval (PcountAC) between the zero-crossing point of phase A and the zero-crossing point of phase C are respectively obtained. Finally, according to the magnitude relationship between the first zero-crossing interval and the second zero-crossing interval, it is judged whether the three-phase alternating current is in an inverse phase sequence; if the first zero-crossing interval is greater than the second zero-crossing interval, it is determined as an inverse phase sequence, that is, a warning operation is triggered to improve the safety of motor operation; if the first zero-crossing interval is not greater than the second zero-crossing interval, it is determined as a positive phase sequence. This embodiment does not need to use an additional hardware circuit to shape the three-phase alternating current, and only needs to detect the inverse phase sequence based on the zero-crossing judgment through Uab, Ubc, and Uca. Figure 2 The flowchart of detecting the voltage values of each phase voltage provided by the embodiment of the present invention is shown.

[0029] According to the embodiment of the present invention, as Figure 2 shown, obtaining the first voltage information, the second voltage information, and the third voltage information according to the first sampling frequency specifically includes: S202, according to the first sampling frequency, triggering at least 2 conversion channels to start analog-to-digital conversion, and each conversion channel performs at least 3 conversion operations to obtain a first analog-to-digital sampling value and a second analog-to-digital sampling value; S204, based on a preset data processing algorithm, respectively obtaining a first analog-to-digital information and a second analog-to-digital information according to the first analog-to-digital sampling value and the second analog-to-digital sampling value; S206, according to the first analog-to-digital information and the second analog-to-digital information, looking up a preset voltage correspondence table to respectively obtain the first voltage information and the second voltage information; S208, calculating the difference between the second voltage information and the first voltage information to obtain the third voltage information.

[0030] It should be noted that the first analog-to-digital sampling value is the real-time analog-to-digital sampling value between phases AB; the second analog-to-digital sampling value is the real-time analog-to-digital sampling value between phases BC; the first analog-to-digital information is the analog value corresponding to the voltage between phases AB (ADab); the second analog-to-digital information is the analog value corresponding to the voltage between phases BC (ADbc).

[0031] In this embodiment, a detection process for the phase voltage is specifically as follows: according to the first sampling frequency, first and second analog-to-digital sampling values are obtained; according to the first and second analog-to-digital sampling values, first and second analog-to-digital information are respectively obtained; according to the first and second analog-to-digital information, the first voltage information and the second voltage information are respectively obtained; the difference between the second voltage information and the first voltage information is calculated to obtain the third voltage information.

[0032] As an implementation manner, by means of an analog-to-digital converter including at least 2 conversion channels, the real-time analog-to-digital sampling values between the AB phases and the real-time analog-to-digital sampling values between the BC phases are respectively measured; wherein, the analog-to-digital converter is an analog-to-digital conversion chip or built in the MCU. At each sampling frequency, each channel performs at least 3 conversion operations to obtain at least 3 analog-to-digital sampling values; preset data processing is performed on the above-mentioned analog-to-digital sampling values and historical mode sampling values; wherein, the data processing methods include but are not limited to Kalman filtering processing, Butterworth filtering processing, weighted mean processing, etc., to obtain the analog values of the corresponding channels. Then, according to the first and 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.

[0033] Figure 3 The execution flowchart of a zero-crossing judgment logic provided by an embodiment of the present invention is shown.

[0034] According to an embodiment of the present invention, as Figure 3 shown, it further includes: S302, obtaining the total number of sampling points; S304, calculating the difference between the second zero-crossing moment and the first zero-crossing moment to obtain the first difference information; S306, judging whether the first difference information is less than 0; S308, if so, calculating the sum of the first difference information and the total number of sampling points to set the first zero-crossing interval; S310, if not, setting the first zero-crossing interval according to the first difference information; S312, calculating the difference between the third zero-crossing moment and the first zero-crossing moment to obtain the second difference information; S314, judging whether the second difference information is less than 0; S316, if so, calculating the sum of the second difference information and the total number of sampling points to set the second zero-crossing interval; S318, if not, setting the second zero-crossing interval according to the second difference information.

[0035] It should be noted that the total number of sampling points is the number of the first analog-to-digital information or the second analog-to-digital information obtained within the same AC cycle. In this embodiment, the execution process of a zero-crossing judgment logic is specifically as follows: obtain the total number of sampling points; calculate 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, update the first zero-crossing interval according to the total number of sampling points; calculate 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, update the second zero-crossing interval according to the total number of sampling points.

[0036] As an implementation manner, the first zero-crossing interval satisfies the following relational expression:

[0037] As an implementation manner, the second zero-crossing interval satisfies the following relational expression:

[0038] In the formula: is the total number of sampling points; is the first zero-crossing interval; is the second zero-crossing interval; is the first zero-crossing moment; is the second zero-crossing moment; is the third zero-crossing moment.

[0039] According to the embodiment of the present invention, it further includes: Within the same AC cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0040] It should be noted that in this embodiment, usually according to the frequency of the AC cycle, several sampling points are set according to the rule of equal time point division. To ensure the acquisition accuracy of the zero-crossing moment, in practical applications, usually at least 64 sampling points are used to control the sampling frequency.

[0041] According to the embodiment of the present invention, it further includes: Within the same AC cycle; If the voltage value of the phase voltage is negative, set the flag information; If the flag information is in a set state and the voltage value of the phase voltage is a positive value 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.

[0042] It should be noted that, in this embodiment, a logic for zero-crossing detection is provided. When the voltage value of the phase voltage is negative, the flag information is set. When the flag information is set and the voltage value of the phase voltage is positive or equal to 0, the current sampling point is recorded as the zero-crossing moment, which is used to indicate the sampling time point when the voltage value of the phase voltage changes from a negative value to a positive value.

[0043] According to an embodiment of the present invention, the triggering warning operation is specifically: Switching the power supply to the motor or issuing a warning signal; 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.

[0044] It should be noted that when a reverse phase sequence is identified, in order to ensure the safety of the motor, protection operations will be performed, including but not limited to switching the motor power supply or issuing a warning signal. By switching the motor power supply, the motor attempts to reset and then detect the phase sequence, thereby improving the safety of the motor. By issuing a warning signal, it is used as a maintenance request to improve the stability of the motor operation. In addition, a fault log is generated based on the voltage value and zero-crossing time of each phase voltage, the first sampling frequency, the warning time and other information, and stored in a non-volatile memory for subsequent query and analysis.

[0045] It is worth mentioning that it also includes: When the motor power supply is switched after judging the triggering of the warning operation; Control the motor to access the backup power supply and enter the energy-saving mode; The control performs a self-test until the phase sequence is positive and switches to the main power supply.

[0046] It should be noted that when the motor power supply is switched after the early warning operation is triggered, if there is a backup power supply, it is connected to the backup power supply and enters the energy-saving mode to prevent the motor from running at high speed. At this time, the main power supply is continuously detected until the phase sequence of the main power supply is positive, and then it is switched back to the main power supply. The motor is powered by the main power supply to restore the normal operation mode.

[0047] It is worth mentioning that it also includes: When a warning signal is issued after the early warning operation is determined to be triggered; Control the motor to enter protection mode and limit the motor starting or running; The control performs a self-check until the phase sequence is positive and the motor restrictions are released.

[0048] It should be noted that when a warning signal is issued after triggering the warning operation, the motor is first controlled to enter the protection mode, restricting the start or operation of the motor to avoid the motor running under the reverse phase sequence condition and causing equipment damage. In addition, the power supply is continuously detected until the power supply phase sequence is the positive phase sequence, and then the normal operation mode of the motor is restored.

[0049] It is worth mentioning that it also includes: Sending the fault log to the fault handling neural network model to obtain maintenance suggestions; Sending a maintenance request according to the maintenance suggestions.

[0050] It should be noted that the fault log is sent to a preset fault handling neural network model to obtain corresponding maintenance suggestions. Then, according to the maintenance suggestions, a corresponding maintenance request is generated and sent to improve the equipment maintenance efficiency and reduce the labor cost of maintenance.

[0051] Figure 4 The block diagram of the reverse phase sequence detection system of the present invention applied to a motor protector is shown.

[0052] As Figure 4 shown, the second aspect of the present invention discloses a reverse phase sequence detection system 4 applied to a motor protector, including a memory 41 and a processor 42. The memory includes 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: Based on a preset AC power cycle frequency, obtain a first sampling frequency; According to the first sampling frequency, obtain first voltage information, second voltage information, and third voltage information; According to the first voltage information, the second voltage information, and the third voltage information, obtain a first zero-crossing moment, a second zero-crossing moment, and a third zero-crossing moment; According to the first zero-crossing moment, the second zero-crossing moment, and the third zero-crossing moment, obtain a first zero-crossing interval and a second zero-crossing interval; Judge whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is a reverse phase sequence, and a warning operation is triggered.

[0053] It should be noted that the frequency of the alternating current cycle is the frequency of the three-phase alternating current to be detected; the first sampling frequency is the time period for triggering the voltage sampling operation; the first voltage information is the voltage value (Uab) between phase A and phase B; the second voltage information is the voltage value (Ubc) between phase B and phase C; the third voltage information is the voltage value (Uca) between phase C and phase A; the first zero-crossing moment is the sampling point serial number (UabCount) corresponding to the zero-crossing of the voltage value of Uab; the second zero-crossing moment is the sampling point serial number (UbcCount) corresponding to the zero-crossing of the voltage value of Ubc; the third zero-crossing moment is the sampling point serial number (UcaCount) corresponding to the zero-crossing of the voltage value of Uca; the first zero-crossing interval is the sampling point serial number interval (PcountAB) between the zero-crossing of phase A and the zero-crossing of phase B; the second zero-crossing interval is the sampling point serial number interval (PcountAC) between the zero-crossing of phase A and the zero-crossing of phase C.

[0054] In this embodiment, an inverse phase sequence detection process applied to a motor protector is provided. First, according to the frequency of the three-phase alternating current, the acquisition frequency of the phase voltage is determined according to the preset total number of samples; where the total number of samples refers to the number of times of measuring the phase voltage within the same three-phase alternating current cycle. Secondly, based on the preset zero-crossing judgment logic, the zero-crossing moments of each phase voltage are obtained according to the voltage values of each phase voltage detected in real time. Then, based on the calculation logic of the preset sampling interval, according to the difference between the zero-crossing moments of each phase voltage, the sampling point serial number interval (PcountAB) between the zero-crossing of phase A and the zero-crossing of phase B and the sampling point serial number interval (PcountAC) between the zero-crossing of phase A and the zero-crossing of phase C are respectively obtained. Finally, according to the magnitude relationship between the first zero-crossing interval and the second zero-crossing interval, it is judged whether the three-phase alternating current is in inverse phase sequence; if the first zero-crossing interval is greater than the second zero-crossing interval, it is determined as inverse phase sequence, that is, the warning operation is triggered to improve the safety of motor operation; if the first zero-crossing interval is not greater than the second zero-crossing interval, it is determined as positive phase sequence. This embodiment does not need to use an additional hardware circuit to shape the three-phase alternating current, and only needs to realize the inverse phase sequence detection based on the zero-crossing judgment through Uab, Ubc and Uca.

[0055] 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 specifically includes: According to the first sampling frequency, at least 2 conversion channels are triggered to start analog-to-digital conversion, and each conversion channel performs at least 3 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, the first analog-to-digital information and the second analog-to-digital information are respectively obtained according to the first analog-to-digital sampling value and the second analog-to-digital sampling value; According to the first analog-to-digital information and the second analog-to-digital information, searching a preset voltage correspondence table to obtain the first voltage information and the second voltage information respectively; A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

[0056] 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 an analog-to-digital value (ADab) corresponding to the voltage between phases AB; and the second analog-to-digital information is an analog-to-digital value (ADbc) corresponding to the voltage between phases BC.

[0057] 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.

[0058] As an implementation method, an analog-to-digital converter including at least two conversion channels is used to measure and obtain the real-time analog-to-digital sampling value between the AB phase and the real-time analog-to-digital sampling value between the BC phase respectively; wherein the analog-to-digital converter is provided by the analog-to-digital conversion chip or the 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 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 processing, Butterworth filtering processing, weighted mean processing, etc., to obtain the analog value of the corresponding channel. Then, according to the first analog-to-digital information and the second analog-to-digital information, the 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.

[0059] According to an embodiment of the present invention, it also includes: Get the total number of sampling points; Calculating the difference between the second zero-crossing point in time and the first zero-crossing point in 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; Calculate the difference between the third zero-crossing moment and the first zero-crossing moment to obtain second difference information; Determine whether the second difference information is less than 0; If so, calculate the sum of the second difference information and the total number of sampling points to set a second zero-crossing interval; If not, set the second zero-crossing interval according to the second difference information.

[0060] It should be noted that the total number of sampling points is the number of first analog information or second analog information obtained within the same AC cycle. In this embodiment, the execution process of a zero-crossing judgment logic is specifically as follows: obtain the total number of sampling points; calculate 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, update the first zero-crossing interval according to the total number of sampling points; calculate 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, update the second zero-crossing interval according to the total number of sampling points.

[0061] As an implementation manner, the first zero-crossing interval satisfies the following relational expression:

[0062] As an implementation manner, the second zero-crossing interval satisfies the following relational expression:

[0063] In the formula: is the total number of sampling points; is the first zero-crossing interval; is the second zero-crossing interval; is the first zero-crossing moment; is the second zero-crossing moment; is the third zero-crossing moment.

[0064] According to the embodiment of the present invention, it further includes: Within the same AC cycle, there are at least 64 sampling points, that is, the total number of sampling points is at least 64.

[0065] It should be noted that in this embodiment, usually according to the frequency of the AC cycle, several sampling points are set according to the rule of equal time point division. To ensure the acquisition accuracy of the zero-crossing moment, in practical applications, usually at least 64 sampling points are used to control the sampling frequency.

[0066] According to an embodiment of the present invention, it further includes: Within the same AC cycle; If the voltage value of the phase voltage is negative, set the flag information; If the flag information is in the set state and the voltage value of the phase voltage is positive or equal to 0, reset the flag information and set the zero-crossing moment of the corresponding phase voltage according to the current sampling point sequence number.

[0067] It should be noted that in this embodiment, a logic for zero-crossing detection is provided. When the voltage value of the phase voltage is negative, the flag information is set. When the flag information is in the set state and the voltage value of the phase voltage is positive or equal to 0, the current sampling point is recorded as the zero-crossing moment, which is used to represent the sampling time point when the voltage value of the phase voltage changes from negative to positive.

[0068] According to an embodiment of the present invention, the triggering of the warning operation is specifically: Switch the motor power supply or issue a warning signal; Generate a fault log according to the voltage value and zero-crossing moment of each phase voltage, the first sampling frequency, and the warning time, and store it in the non-volatile memory.

[0069] It should be noted that when it is determined to be reverse phase sequence, to ensure the safe use of the motor, protection operations will be performed, including but not limited to switching the motor power supply or issuing a warning signal. By switching the motor power supply, the motor attempts to reset and then the phase sequence is detected again, improving the safety of the motor. By issuing a warning signal, it is used as a maintenance request, improving the stability of the motor operation. In addition, a fault log is generated according to the voltage value and zero-crossing moment of each phase voltage, the first sampling frequency, the warning time, etc., and stored in the non-volatile memory for subsequent query and analysis.

[0070] It is worth mentioning that it further includes: When judging to switch the motor power supply after triggering the warning operation; Control the motor to connect to the standby power supply and enter the energy-saving mode; Control to perform self-check until it is positive phase sequence and then switch to the main power supply.

[0071] It should be noted that when switching the motor power supply after triggering the warning operation, if there is a standby power supply, it is connected to the standby power supply and enters the energy-saving mode to avoid the motor running at high speed. At this time, the main power supply is continuously detected until the main power supply phase sequence is positive phase sequence, and then it is switched back to the main power supply. Through the main power supply, the normal operation mode of the motor is restored.

[0072] It is worth mentioning that it further includes: When judging to issue a warning signal after triggering the warning operation; Control the motor to enter protection mode and limit the motor starting or running; The control performs a self-check until the phase sequence is positive and the motor restrictions are released.

[0073] It should be noted that when a warning signal is issued after the early warning operation is triggered, the motor is first controlled to enter the protection mode to limit the motor starting or running to prevent the motor from running under the reverse phase sequence condition and causing equipment damage. In addition, the power supply is continuously tested until the power supply phase sequence is positive, and the normal operation mode of the motor is restored.

[0074] It is worth mentioning that it also includes: Sending the fault log to a fault processing neural network model to obtain maintenance suggestions; A maintenance request is sent according to the maintenance suggestion.

[0075] It should be noted that the fault log is sent to the preset fault processing neural network model to obtain the corresponding maintenance suggestions. Then, according to the maintenance suggestions, the corresponding maintenance request is generated and sent to improve the equipment maintenance efficiency and reduce the maintenance labor cost.

[0076] A 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.

[0077] 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 calculation, reduces the MCU computing burden, and achieves a balance between low cost, high response speed and multi-function protection while ensuring detection accuracy, providing reliable technical support for the safe operation of the motor.

[0078] When the above-mentioned functions are implemented in the form of software function 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, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0079] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A reverse phase sequence detection method applied to a motor protector, characterized in that: The method comprises: Based on the preset alternating current cycle frequency, obtaining a first sampling frequency; According to the first sampling frequency, first voltage information, second voltage information and third voltage information are obtained, wherein the first voltage information, the second voltage information and the third voltage information are voltage information of different phase voltages; 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; Determining whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is a reverse phase sequence, triggering a warning operation.

2. The reverse phase sequence detection method for a motor protector according to claim 1 is characterized in that: The obtaining of the first voltage information, the second voltage information and the third voltage information according to the first sampling frequency is specifically: According to the first sampling frequency, trigger at least two conversion channels to start analog-to-digital conversion, 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; Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information respectively according to the first analog-to-digital sampling value and the second analog-to-digital sampling value; According to the first analog-to-digital information and the second analog-to-digital information, searching a preset voltage correspondence table to obtain the first voltage information and the second voltage information respectively; A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

3. The reverse phase sequence detection method for a motor protector according to claim 1, characterized in that: Also includes: Get the total number of sampling points; Calculating the difference between the second zero-crossing point in time and the first zero-crossing point in 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 the difference between the third zero-crossing point in time and the first zero-crossing point in time to obtain second difference information; Determine whether the second difference information is less than 0; If yes, then calculate the sum of the second difference information and the total number of sampling points, and set a second zero-crossing interval; If not, the second zero-crossing interval is set according to the second difference information.

4. The reverse phase sequence detection method for a motor protector according to claim 3 is characterized in that: 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.

5. 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 a positive value 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.

6. The reverse phase sequence detection method for a motor protector according to claim 1, characterized in that: The triggering warning operation is specifically: Switching the power supply to the motor or issuing a warning signal; 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.

7. 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 following steps are implemented: Based on the preset alternating current cycle frequency, obtaining a first sampling frequency; According to the first sampling frequency, first voltage information, second voltage information and third voltage information are obtained, wherein the first voltage information, the second voltage information and the third voltage information are voltage information of different phase voltages; 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; Determining whether the first zero-crossing interval is greater than the second zero-crossing interval; If so, it is a reverse phase sequence, triggering a warning operation.

8. The reverse phase sequence detection system for a motor protector according to claim 7, characterized in that: The obtaining of the first voltage information, the second voltage information and the third voltage information according to the first sampling frequency is specifically: According to the first sampling frequency, trigger at least two conversion channels to start analog-to-digital conversion, 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; Based on a preset data processing algorithm, obtaining first analog-to-digital information and second analog-to-digital information respectively according to the first analog-to-digital sampling value and the second analog-to-digital sampling value; According to the first analog-to-digital information and the second analog-to-digital information, searching a preset voltage correspondence table to obtain the first voltage information and the second voltage information respectively; A difference between the second voltage information and the first voltage information is calculated to obtain third voltage information.

9. The reverse phase sequence detection system for a motor protector according to claim 7, characterized in that: Also includes: Get the total number of sampling points; Calculating the difference between the second zero-crossing point in time and the first zero-crossing point in 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 the difference between the third zero-crossing point in time and the first zero-crossing point in time to obtain second difference information; Determine whether the second difference information is less than 0; If yes, then calculate the sum of the second difference information and the total number of sampling points, and set a second zero-crossing interval; If not, the second zero-crossing interval is set according to the second difference information.

10. 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 6 are implemented.

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