Single-phase asynchronous motor starting control circuit with anomaly detection function

Abstract

The invention relates to the technical field of single-phase asynchronous motors, and discloses a single-phase asynchronous motor starting control circuit with anomaly detection, which comprises an MCU (Microprogrammed Control Unit), a main silicon controlled rectifier, an auxiliary silicon controlled rectifier, an electric metering chip and a protection circuit, the main silicon controlled rectifier, the auxiliary silicon controlled rectifier, the electric metering chip and the protection circuit are directly or indirectly electrically connected to the MCU control unit, and the MCU control unit is used for executing control logic, so that the on-off time sequence of the main silicon controlled rectifier and the auxiliary silicon controlled rectifier can be accurately controlled, the starting process of the motor is optimized, the starting impact is reduced, and the service life of the motor is prolonged. And abnormal state judgment can be carried out according to real-time current and voltage data provided by the electric metering chip, and protection measures can be taken quickly when abnormity is detected. In addition, key operation parameters when the abnormal state occurs are recorded, a basis is provided for subsequent fault analysis, the fault diagnosis process is greatly simplified, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of single-phase asynchronous motors, and more specifically, to a single-phase asynchronous motor starting control circuit with abnormality detection. Background Art

[0002] Traditional starting methods for single-phase asynchronous motors rely on PTC thermal starters or heavy hammer mechanical starters. While simple to implement, these methods have numerous shortcomings in practice, particularly in terms of operational reliability and ease of maintenance.

[0003] First, traditional starters lack intelligent control mechanisms, making it difficult to dynamically adjust starting parameters based on load changes. This can easily lead to starting failures or excessive current surges, impacting grid stability. Second, these starting devices generally lack real-time monitoring capabilities, making it impossible to effectively collect and analyze key parameters such as current, voltage, and power during motor operation. Consequently, when an anomaly or fault occurs, the system cannot provide effective data support, making it difficult for maintenance personnel to accurately determine the cause of the fault, resulting in difficult troubleshooting, long repair cycles, and high maintenance costs.

[0004] Furthermore, traditional starters often rely on passive protection methods, such as temperature changes or mechanical contact disconnection. These methods are slow to respond and susceptible to environmental factors, posing significant safety risks. For example, PTC starters are prone to aging and failure due to frequent starts and stops or high temperatures, while the mechanical contacts of heavy hammer starters are susceptible to wear and oxidation, resulting in poor contact or even complete failure. Summary of the Invention

[0005] To solve the above problems, the present application proposes a single-phase asynchronous motor starting control circuit with abnormality detection.

[0006] According to one aspect of the present application, a single-phase asynchronous motor starting control circuit with abnormality detection is provided, comprising: an MCU control unit, a main thyristor, a secondary thyristor, an electricity metering chip, and a protection circuit; the main thyristor, the secondary thyristor, the electricity metering chip, and the protection circuit are directly or indirectly electrically connected to the MCU control unit; wherein the MCU control unit is used to execute control logic, the control logic including controlling the on and off timing of the main thyristor and the secondary thyristor, performing abnormal state judgment based on real-time data from the electricity metering chip, executing protection actions, and recording key operating parameters when the abnormal state occurs.

[0007] In one possible implementation, abnormal state determination based on real-time data from an electricity metering chip includes: receiving a real-time effective current value collected by the electricity metering chip; comparing the real-time effective current value with a current dynamic protection threshold to determine whether a first condition is met; and, when it is determined that the first condition is met, causing an MCU control unit to shut down a main thyristor.

[0008] In a possible implementation, the first condition is that the effective current value exceeds the current dynamic protection threshold and the duration exceeds a preset filtering time.

[0009] In one possible implementation, setting the current dynamic protection threshold includes: in the motor startup phase, high-frequency sampling of effective current values ​​and effective voltage values ​​through an electricity metering chip to obtain a series of startup phase effective current values ​​and a series of startup phase effective voltage values; identifying a peak startup current value from the series of startup phase effective current values; calculating a startup voltage value based on a timestamp of the peak startup current value and the series of startup phase effective voltage values; calculating a reference overcurrent protection threshold based on the peak startup current value and the startup voltage value; in the stable operation phase of the motor, low-frequency sampling of effective current values ​​and effective voltage values ​​through an electricity metering chip to obtain an operating phase effective current value and an operating phase effective voltage value; calculating a dynamic adjustment coefficient based on the operating phase effective current value and the operating phase effective voltage value; and dynamically adjusting the reference overcurrent protection threshold based on the dynamic adjustment coefficient to obtain the current dynamic protection threshold.

[0010] In one possible implementation, the starting voltage value is calculated based on the timestamp of the peak starting current value and the series of starting phase effective voltage values, including: based on the timestamp of the peak starting current value, cutting a short-time window near the peak value of the effective voltage value from the series of starting phase effective voltage values, wherein the timestamp of the peak starting current value is located at the center of the short-time window near the peak value of the effective voltage value; and calculating the average of all starting phase effective voltage values ​​in the short-time window near the peak value of the effective voltage value as the starting voltage value.

[0011] In one possible implementation, calculating a reference overcurrent protection threshold based on the peak starting current value and the starting voltage value includes calculating the reference overcurrent protection threshold based on the peak starting current value and the starting voltage value using the following formula, where the formula is: ;in, is the peak starting current value, is the starting voltage value, It is the multiple of the preset peak starting current value and the rated operating current value. is the preset overload factor, Indicates the baseline overcurrent protection threshold.

[0012] In one possible implementation, the startup phase is determined and , including: obtaining general operation stage values and ;based on The reciprocal of and The probability coupling relationship between the first dynamic balance quantization modeling coefficient and the second dynamic balance quantization modeling coefficient is calculated; based on the first dynamic balance quantization modeling coefficient and the second dynamic balance quantization modeling coefficient, Perform smoothing adjustment based on correlation mutation to obtain a smoothing adjustment factor; based on the first dynamic balance quantitative modeling coefficient, the second dynamic balance quantitative modeling coefficient and the smoothing adjustment factor, and Calibration is performed to obtain the startup phase and .

[0013] In one possible implementation, a dynamic adjustment coefficient is calculated based on the effective current value and the effective voltage value in the operating stage, including: calculating a current active power value based on the effective current value and the effective voltage value in the operating stage, wherein the current active power value is the effective current value in the operating stage multiplied by the effective voltage value in the operating stage and then multiplied by the power factor; an MCU control unit obtains a rated active power value; based on the current active power value and the rated active power value, a normalized load factor is calculated, wherein the normalized load factor is the current active power value divided by the rated active power value; based on the normalized load factor, a load discrete level label is determined; and based on the load discrete level label, the dynamic adjustment coefficient is matched from a dynamic adjustment coefficient table.

[0014] In a possible implementation, the discrete load level labels include no load, very light load, medium load, rated load, and instantaneous overload.

[0015] Compared to the prior art, the single-phase asynchronous motor starting control circuit with abnormality detection provided by this application includes an MCU control unit, a main thyristor, a secondary thyristor, an electricity metering chip, and a protection circuit; the main thyristor, the secondary thyristor, the electricity metering chip, and the protection circuit are directly or indirectly electrically connected to the MCU control unit. The MCU control unit is used to execute control logic, which not only accurately controls the on- and off-time of the main and secondary thyristors to optimize the motor starting process and reduce starting shock, but also determines abnormal conditions based on the real-time current and voltage data provided by the electricity metering chip and quickly takes protective measures when an abnormality is detected. In addition, it also records key operating parameters when the abnormal condition occurs, providing a basis for subsequent fault analysis, greatly simplifying the fault diagnosis process and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other purposes, features, and advantages of the present application will become more apparent through a more detailed description of the embodiments of the present application in conjunction with the accompanying drawings. The accompanying drawings are intended to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 The figure illustrates a schematic principle block diagram of a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application.

[0018] Figure 2 The figure shows a schematic flow chart of abnormal state judgment based on real-time data from an electricity metering chip in a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application.

[0019] Figure 3 The figure illustrates a schematic flow chart of setting the current dynamic protection threshold in a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application.

[0020] Figure 4 The figure illustrates a schematic flowchart of calculating the starting voltage value based on the timestamp of the peak starting current value and the series of effective voltage values ​​in the starting stage in a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application.

[0021] Figure 5 The figure illustrates a schematic flow chart of calculating a dynamic adjustment coefficient based on the effective current value and the effective voltage value in the operating phase in a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] Below, the exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the exemplary embodiments described herein.

[0023] Figure 1 The figure shows a schematic principle block diagram of a single-phase asynchronous motor starting control circuit with abnormality detection according to an embodiment of the present application. Figure 1 As shown, the present application provides a single-phase asynchronous motor starting control circuit with abnormality detection, comprising: an MCU control unit, a main thyristor, a secondary thyristor, an electricity metering chip and a protection circuit; the main thyristor, the secondary thyristor, the electricity metering chip and the protection circuit are directly or indirectly electrically connected to the MCU control unit; wherein the MCU control unit is used to execute control logic, and the control logic includes controlling the on and off timing of the main thyristor and the secondary thyristor, performing abnormal state judgment based on real-time data from the electricity metering chip, executing protection actions and recording key operating parameters when the abnormal state occurs.

[0024] Specifically, the core of the single-phase asynchronous motor starting control circuit with anomaly detection lies in the MCU control unit. As the intelligent processing center of the entire system, it features high flexibility and strong computing power. The MCU is responsible for receiving and processing real-time operating data from the electricity metering chip, including parameters such as current, voltage, and power. This real-time data not only reflects the motor's operating status but also serves as an important basis for the circuit to detect abnormal conditions. Based on this data, the MCU executes pre-set control logic to handle various tasks during the startup and operation phases. During startup, the MCU controls the on-off timing of the main and auxiliary thyristors to provide the motor with the optimal starting current and starting torque, ensuring a smooth start. During the operation phase, the MCU continuously monitors load data and dynamically adjusts its strategy to further optimize system efficiency. Furthermore, if the MCU detects an abnormality such as overcurrent, overvoltage, or overheating, it executes a protection program to quickly shut down the circuit, ensuring safe operation of the motor and circuits. As the control core, the MCU also records key operating parameters, providing reliable data support for remote diagnosis and subsequent optimization of the system.

[0025] The main thyristor (SCR) and slave thyristor (SCR) each play different roles in the circuit. The main SCR is located at a key position in the motor's main circuit control circuit, primarily controlling the main power supply on and off. During the startup phase, the MCU (MCU) control unit triggers the main SCR based on real-time current and voltage signals, energizing the motor's main winding and providing the necessary operating conditions. When the motor enters a stable operating state, the main SCR continues to operate, maintaining on-off control of the main circuit. If the system triggers a protection action under certain abnormal conditions, the MCU control unit immediately shuts off the main SCR, quickly terminating the power supply to prevent motor overload or system damage. The slave SCR's role is more focused on the motor startup phase, temporarily energizing the motor's auxiliary starting winding to provide additional starting torque during the initial startup phase. Once the motor has successfully started and reached a stable speed, the slave SCR shuts off under the MCU's command, disconnecting the starting winding and preventing unnecessary energy consumption. The coordinated operation of the main and slave SCRs significantly improves the motor's starting efficiency and operational stability.

[0026] The energy metering chip, as the core data acquisition module, is directly connected between the power supply and the load, using high-frequency sampling technology to monitor changes in key circuit parameters in real time. During the startup phase, the current and voltage data collected by the energy metering chip is transmitted to the MCU control unit to calculate dynamic startup parameters, including the startup current threshold and overcurrent protection threshold. These parameters provide the basis for the MCU control of the trigger angle and on-off timing of the main and secondary thyristors. After the motor enters stable operation, the energy metering chip continues to transmit the operating current and voltage parameters back to the MCU control unit through low-frequency sampling, which is used to dynamically adjust the system strategy. This dynamic sampling and adjustment method achieves significant optimization of the system protection threshold through intelligent analysis based on real-time data. The data provided by the energy metering chip also helps the MCU control unit establish a comprehensive load analysis model, achieve accurate load status labeling and classification, and design the optimal operation strategy for different load conditions.

[0027] The protection circuit plays a crucial role in this single-phase asynchronous motor starting control circuit, designed to provide hardware-level safety assurance for the system. The protection circuit comprises multiple hardware components that rapidly respond to abnormal conditions in the system through electromagnetic means. In the system, when the MCU control unit detects an emergency condition such as overcurrent, overvoltage, overheating, or short circuit via the electricity metering chip, the protection circuit immediately activates, shutting off the critical power supply path in the circuit to prevent the accident from escalating. The protection circuit also supports setting the overload duration, enabling the system to temporarily tolerate transient overload peaks to avoid false protection. This multi-layered protection mechanism, working in conjunction with the intelligent operation of the MCU control unit, significantly improves the reliability and risk resistance of the entire circuit.

[0028] Specifically, the control of the on- and off-time sequence of the main thyristor and the auxiliary thyristor includes the following: During the startup phase, the auxiliary thyristor is first activated to connect the power supply to the starting winding. During this phase, the MCU control unit monitors the current, voltage, and power data in the circuit in real time via the power metering chip to determine whether the motor is currently in a suitable state for starting. When the system determines that the load conditions and electrical parameters meet the startup requirements, the MCU control unit sends a trigger signal to the auxiliary thyristor to energize the starting winding. During this phase, the starting winding provides additional starting torque to overcome the static inertia of the motor when it is stopped, achieving initial rotor acceleration. During this phase, the MCU control unit dynamically adjusts the auxiliary thyristor's trigger angle based on current trends fed back by the power metering chip to suppress the peak starting current and reduce the impact on the power grid. Simultaneously, the MCU control unit continuously monitors the increase in the back-electromotive force signal. When this signal indicates that the rotor has reached the critical starting speed, the operating state of the auxiliary thyristor begins to change, preparing for the next switching.

[0029] As the startup process nears its end, the main thyristor (SCR) enters the core control logic, with the MCU triggering its on-signal to connect the main winding. As the motor's primary drive structure, the main winding officially takes over control of system operation at this point, switching the motor from startup mode to normal operation. The MCU dynamically calculates the trigger angle of the main SCR based on historical startup monitoring data and the current load demand of the main winding. This precise control method significantly reduces pulse fluctuations during startup transitions and improves overall operating efficiency. After the main SCR turns on, the MCU gradually deactivates the starting winding and sends a shutdown signal to disconnect the secondary SCR, thereby reducing the energy waste caused by the uninterrupted power supply to the starting winding.

[0030] At the same time, the MCU control unit will also make abnormal status judgments based on real-time data from the electricity metering chip. If an abnormal operating status is encountered, the MCU control unit will immediately shut down the main thyristor and cut off the power supply to the main winding to avoid equipment damage or further expansion of the fault.

[0031] In one embodiment, Figure 2 As shown, abnormal state judgment is performed based on real-time data from the electricity metering chip, including: S1, receiving the real-time effective current value collected by the electricity metering chip; S2, comparing the real-time effective current value with the current dynamic protection threshold to determine whether a first condition is met; S3, when it is determined that the first condition is met, the MCU control unit turns off the main thyristor.

[0032] Specifically, the electricity metering chip's real-time data acquisition capabilities and its sampling mechanism utilize a high-frequency mode during the motor startup phase, accurately recording instantaneous fluctuations in current and voltage, thereby capturing the peak characteristics of each electrical parameter during the startup process. This data serves as a key basis for the MCU control unit to determine whether the motor is operating normally. Specifically, the MCU control unit receives the real-time effective current value collected by the electricity metering chip and compares it with the current dynamic protection threshold based on predefined abnormality judgment logic. Specifically, the real-time effective current value is compared with the current dynamic protection threshold to determine whether a first condition is met. If the first condition is determined to be met, the MCU control unit triggers the abnormality protection logic, immediately shutting down the main thyristor.

[0033] In one embodiment, the first condition is that the effective current value exceeds the dynamic current protection threshold and lasts longer than a preset filtering time. It should be understood that current fluctuations are normal during the operation of single-phase asynchronous motors. This includes high current peaks during startup and random interference during operation. These interferences may arise from short-term electrical parameter anomalies caused by external load changes, power supply fluctuations, or environmental factors. However, these short-term current fluctuations are part of normal operation for most motors and generally do not pose a potential hazard to the motor. Without a filter time design, for example, requiring that any current exceeding the protection threshold trigger an immediate protection action, there is a high probability of unnecessary shutdowns, thus affecting system stability and user experience. Furthermore, relying solely on dynamic protection thresholds for judgment is not ideal. Short-term peak currents are a typical phenomenon during startup. Without a time constraint, these could potentially interfere with the startup process. Therefore, the requirement for a duration exceeding the preset filtering time adds an additional judgment dimension to the time axis, enabling more efficient screening of anomaly judgments.

[0034] In one specific embodiment, during the startup phase, the high-frequency sampling mechanism of the electricity metering chip captures instantaneous current peaks in real time and uses this information to adjust the dynamic protection threshold. The filtering time is set relatively short, typically on the order of one to several milliseconds, to quickly identify abnormal conditions during startup. For example, when a motor starts, the effective current rises rapidly and may exceed the dynamic protection threshold. At this point, the MCU starts a timer to monitor whether the current continues to exceed this threshold. If the duration exceeds the defined filtering time, the startup process is deemed to have a fault, such as a short circuit or motor jam. If the duration does not reach the filtering time, the MCU considers the current change to be part of the startup characteristic rather than an anomaly and does not trigger the protection action. This timeline-based logic avoids misoperation and provides the necessary tolerance for the motor to complete startup.

[0035] The implementation logic during the operation phase differs slightly. Because current fluctuations are typically less severe than during the startup phase, the filtering time is set relatively long during this phase to further accommodate load changes during operation. During this phase, the low-frequency sampling mechanism of the electricity metering chip is utilized, and the MCU analyzes the effective current trend in real time. If the operating current continuously exceeds the protection threshold and persists for longer than the preset filtering time (e.g., more than 50 milliseconds), the system will determine that an overload or other abnormality exists. If the motor enters an overload state, it may cause an abnormal increase in winding temperature and even damage the motor itself. In this case, once the filtering time expires, the MCU control unit will respond quickly, shutting down the main thyristor to disconnect the power supply path, thereby protecting the motor.

[0036] In one embodiment, Figure 3 As shown, the setting of the current dynamic protection threshold includes: during the motor startup phase, S21, high-frequency sampling of effective current and effective voltage values ​​using an electricity metering chip to obtain a series of effective current values ​​and a series of effective voltage values ​​during the startup phase; S22, identifying a peak startup current value from the series of effective current values ​​during the startup phase; S23, calculating a startup voltage value based on the timestamp of the peak startup current value and the series of effective voltage values ​​during the startup phase; S24, calculating a baseline overcurrent protection threshold based on the peak startup current value and the startup voltage value. During the motor's stable operation phase, S25, low-frequency sampling of effective current and effective voltage values ​​using an electricity metering chip to obtain an effective current value and an effective voltage value during the operation phase; S26, calculating a dynamic adjustment coefficient based on the effective current value and the effective voltage value during the operation phase; and S27, dynamically adjusting the baseline overcurrent protection threshold based on the dynamic adjustment coefficient to obtain the current dynamic protection threshold.

[0037] During the motor startup phase, the power metering chip continuously samples effective current and effective voltage values ​​using a high-frequency sampling mechanism (typically several kilohertz, such as 5kHz or 10kHz), generating a series of startup data sets. This data set provides a complete record of the electrical characteristics during startup and is the basis for identifying peak starting current values. The effective current peak often occurs just as the motor begins to overcome the static torque, when the current rises rapidly and forms a noticeable peak fluctuation. The MCU monitors this trend in real time. Using the continuously sampled current curve, it compares data from adjacent time points to identify the maximum starting current value, accurately confirming the peak starting current value and its corresponding timestamp.

[0038] Once the timestamp of the peak starting current value is determined, the process of calculating the starting voltage value will be carried out. Figure 4As shown, the starting voltage value is calculated based on the timestamp of the peak starting current value and the series of effective voltage values ​​in the starting stage, including: S231, based on the timestamp of the peak starting current value, cutting a short-time window near the peak of the effective voltage value from the series of effective voltage values ​​in the starting stage, wherein the timestamp of the peak starting current value is located at the center position of the short-time window near the peak of the effective voltage value; S232, calculating the average of all effective voltage values ​​in the starting stage in the short-time window near the peak of the effective voltage value as the starting voltage value.

[0039] In one embodiment, calculating a reference overcurrent protection threshold based on the peak starting current value and the starting voltage value includes: calculating the reference overcurrent protection threshold based on the peak starting current value and the starting voltage value using the following formula, wherein the formula is: ;in, is the peak starting current value, is the starting voltage value, It is the multiple of the preset peak starting current value and the rated operating current value. is the preset overload factor, Represents the baseline overcurrent protection threshold. The multiple between the preset peak starting current value and the rated operating current value reflects the difference in current characteristics between the motor starting process and the stable operation stage; the preset overload factor indicates the ratio of the maximum current allowed by the system to the rated current value. It directly determines the sensitivity of the protection threshold to dynamic changes and can be obtained according to the motor type or specific load characteristics, for example Of course, this is just an example and can be adjusted according to actual conditions. This application does not make any specific limitations.

[0040] here, As a multiple of the preset peak starting current value and the rated operating current value, and As the preset overload factor, it reflects the ratio between the maximum allowable current and the rated operating current value. and However, due to the difference between the starting phase and the stable operation phase of the single-phase asynchronous motor, it is not suitable to directly determine the starting phase involved here with the commonly used operating phase values. and That is, during the startup phase, and The dynamic balance relationship between them is adjusted to avoid distortion of the overload factor preset due to transient processes.

[0041] Based on this, in another embodiment, the startup phase is determined and , including: first obtain the general operation stage value and , can be obtained according to the motor type or specific load characteristics in the previous embodiment, for example , then based on The reciprocal of and The probability coupling relationship between them is used to calculate the first dynamic balance quantitative modeling coefficient and the second dynamic balance quantitative modeling coefficient, which can be expressed as: ;in Adjust parameters for dynamic correlation balance, represents the first dynamic equilibrium quantitative modeling coefficient, It represents the second dynamic balance quantitative modeling coefficient, that is, the higher the multiple between the peak starting current value and the rated operating current value, the lower the preset overload coefficient should be set to play a dynamic protection role.

[0042] But at the same time, smooth adjustment based on correlation mutation is also required, which can be achieved by introducing the natural logarithm function, that is, based on the first dynamic balance quantitative modeling coefficient and the second dynamic balance quantitative modeling coefficient, A smoothing adjustment based on correlation mutation is performed to obtain a smoothing adjustment factor, which is expressed as: ;in, is a mutation adjustment parameter used to characterize the tolerance for correlation mutations. represents the smoothing adjustment factor, Represents the natural logarithm function.

[0043] In this way, based on the first dynamic balance quantitative modeling coefficient, the second dynamic balance quantitative modeling coefficient and the smoothing adjustment factor, and Calibration is performed to obtain the startup phase and , in this way and The dynamic balance relationship between them is regulated, namely: Thus, in the correction process, while smoothing adjustment is performed based on the natural logarithmic function, the sensitivity to low correlation values ​​is enhanced by square root operation as a nonlinear miscorrelation characteristic suppression, so that the above and There is a dynamic balance relationship of probabilistic coupling and coordination between them, which improves its numerical accuracy and thus improves the benchmark overcurrent protection during the motor startup phase.

[0044] Next, considering the complex and diverse load variations experienced by single-phase asynchronous motors during actual operation, this operating environment exceeds the sensitivity range of traditional fixed-threshold protection mechanisms. Therefore, during the motor's stable operation phase, the power metering chip samples the effective current and voltage values ​​at a low frequency (e.g., 50Hz to 200Hz) to obtain the operating phase effective current and voltage values. Based on these operating phase effective current and voltage values, a dynamic adjustment coefficient is calculated. The baseline overcurrent protection threshold is dynamically adjusted based on this dynamic adjustment coefficient to obtain the current dynamic protection threshold. Dynamically adjusting the baseline overcurrent protection threshold based on the dynamic adjustment coefficient is designed to account for the motor's protection requirements under varying load levels, ensuring that the motor remains in a safe protection state while preventing false triggering due to overly stringent protection or hardware damage caused by delayed protection. The dynamic adjustment mechanism achieves a balanced performance and protection by adjusting the protection strategy based on the current load state. In particular, the introduction of the dynamic adjustment coefficient effectively adapts to the significant difference between the high current fluctuations during startup and the steady current during stable operation, enhancing system flexibility.

[0045] In one embodiment, Figure 5 As shown, based on the effective current value and the effective voltage value of the operating stage, the dynamic adjustment coefficient is calculated, including: S261, based on the effective current value and the effective voltage value of the operating stage, the current active power value is calculated, and the current active power value is the effective current value of the operating stage multiplied by the effective voltage value of the operating stage and then multiplied by the power factor; S262, the MCU control unit obtains the rated active power value; S263, based on the current active power value and the rated active power value, a normalized load factor is calculated, and the normalized load factor is the current active power value divided by the rated active power value; S264, based on the normalized load factor, a load discrete level label is determined; S265, based on the load discrete level label, the dynamic adjustment coefficient is matched from the dynamic adjustment coefficient table.

[0046] In a specific embodiment, the effective current value during the operation phase is 10A, the effective voltage value during the operation phase is 220V, and the power factor is 0.85. Therefore, the current active power is calculated as 10×220×0.85=1870W. At the same time, the preset rated active power is 2000W. Therefore, the normalized load factor is calculated as 1870÷2000=0.935. This value is close to the rated load range, indicating that the motor is currently operating under a relatively normal operating load state. Then, based on this normalized load factor, a corresponding dynamic adjustment coefficient can be matched. In one embodiment, the load discrete level labels include no load, very light load, medium load, rated load, and instantaneous overload. The label corresponding to the normalized load factor of 0.935 is rated load, and the matched dynamic adjustment coefficient is 0.9. Finally, based on the calculated dynamic adjustment coefficient, the baseline overcurrent protection threshold is dynamically adjusted to obtain the current dynamic protection threshold. Specifically, the current dynamic protection threshold can be obtained by multiplying the dynamic adjustment coefficient by the baseline overcurrent protection threshold. At the same time, when the real-time effective current value exceeds the dynamic protection threshold and the duration exceeds the preset filtering time, the protection action is triggered and abnormal data recording is simultaneously started. The system stores all parameters related to the abnormality in the internal storage module, including the current peak value, voltage peak value, the timestamp of the abnormality, and the dynamic adjustment coefficient.

[0047] In summary, the single-phase asynchronous motor starting control circuit with abnormality detection provided by the present application includes an MCU control unit, a main thyristor, a secondary thyristor, an electricity metering chip, and a protection circuit; the main thyristor, the secondary thyristor, the electricity metering chip, and the protection circuit are directly or indirectly electrically connected to the MCU control unit, wherein the MCU control unit is used to execute the control logic, which can not only accurately control the on and off timing of the main and secondary thyristors to optimize the motor starting process and reduce the starting impact, but also judge the abnormal state based on the real-time current and voltage data provided by the electricity metering chip, and quickly take protective measures when an abnormality is detected. In addition, the key operating parameters when the abnormal state occurs are recorded to provide a basis for subsequent fault analysis, greatly simplifying the fault diagnosis process and reducing maintenance costs.

[0048] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0049] The flowcharts of the methods involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the flowcharts. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems may be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and may be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and may be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and may be used interchangeably therewith.

[0050] It should also be noted that in the method of the present application, each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0051] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0052] The above description has been provided for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A single-phase asynchronous motor starting control circuit with abnormality detection, characterized in that: The single-phase asynchronous motor starting control circuit includes an MCU control unit, a main thyristor, a secondary thyristor, an electricity metering chip, and a protection circuit; the main thyristor, the secondary thyristor, the electricity metering chip, and the protection circuit are directly or indirectly electrically connected to the MCU control unit; wherein the MCU control unit is used to execute control logic, which includes controlling the on and off timing of the main thyristor and the secondary thyristor, performing abnormal state judgment based on real-time data from the electricity metering chip, executing protection actions, and recording key operating parameters when the abnormal state occurs.

2. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 1, characterized in that: An abnormal state judgment is performed based on real-time data from an electricity metering chip, including: receiving a real-time effective current value collected by the electricity metering chip; comparing the real-time effective current value with a current dynamic protection threshold to determine whether a first condition is met; and when it is determined that the first condition is met, an MCU control unit turns off a main thyristor.

3. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 2, characterized in that: The first condition is that the effective current value exceeds the current dynamic protection threshold and the duration exceeds the preset filtering time.

4. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 2, characterized in that: The setting of the current dynamic protection threshold includes: in the motor starting stage, high-frequency sampling of effective current values ​​and effective voltage values ​​through the electric metering chip to obtain a series of effective current values ​​and a series of effective voltage values ​​in the starting stage; identifying the peak starting current value from the series of effective current values ​​in the starting stage; calculating the starting voltage value based on the timestamp of the peak starting current value and the series of effective voltage values ​​in the starting stage; calculating the reference overcurrent protection threshold based on the peak starting current value and the starting voltage value; in the stable operation stage of the motor, low-frequency sampling of effective current values ​​and effective voltage values ​​through the electric metering chip to obtain an effective current value and an effective voltage value in the running stage; calculating a dynamic adjustment coefficient based on the effective current value and the effective voltage value in the running stage; and dynamically adjusting the reference overcurrent protection threshold based on the dynamic adjustment coefficient to obtain the current dynamic protection threshold.

5. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 4, characterized in that: The starting voltage value is calculated based on the timestamp of the peak starting current value and the series of effective voltage values ​​in the starting stage, including: based on the timestamp of the peak starting current value, cutting a short-time window near the peak value of the effective voltage value from the series of effective voltage values ​​in the starting stage, wherein the timestamp of the peak starting current value is located at the center position of the short-time window near the peak value of the effective voltage value; and calculating the average of all effective voltage values ​​in the starting stage in the short-time window near the peak value of the effective voltage value as the starting voltage value.

6. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 4, characterized in that: Calculating a reference overcurrent protection threshold based on the peak starting current value and the starting voltage value includes: calculating the reference overcurrent protection threshold based on the peak starting current value and the starting voltage value using the following formula, wherein the formula is: ;in, is the peak starting current value, is the starting voltage value, It is the multiple of the preset peak starting current value and the rated operating current value. is the preset overload factor, Indicates the baseline overcurrent protection threshold.

7. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 6, characterized in that: Determine the start-up phase and , including: obtaining general operation stage values and ;based on The reciprocal of and The probability coupling relationship between the first dynamic balance quantization modeling coefficient and the second dynamic balance quantization modeling coefficient is calculated; based on the first dynamic balance quantization modeling coefficient and the second dynamic balance quantization modeling coefficient, Perform smoothing adjustment based on correlation mutation to obtain a smoothing adjustment factor; based on the first dynamic balance quantitative modeling coefficient, the second dynamic balance quantitative modeling coefficient and the smoothing adjustment factor, and Calibration is performed to obtain the startup phase and .

8. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 4, characterized in that: Based on the effective current value and the effective voltage value in the operating stage, a dynamic adjustment coefficient is calculated, including: based on the effective current value and the effective voltage value in the operating stage, a current active power value is calculated, the current active power value is the effective current value in the operating stage multiplied by the effective voltage value in the operating stage and then multiplied by the power factor; the MCU control unit obtains the rated active power value; based on the current active power value and the rated active power value, a normalized load factor is calculated, the normalized load factor is the current active power value divided by the rated active power value; based on the normalized load factor, a load discrete level label is determined; based on the load discrete level label, the dynamic adjustment coefficient is matched from a dynamic adjustment coefficient table.

9. The single-phase asynchronous motor starting control circuit with abnormality detection according to claim 8, characterized in that: The load discrete level labels include no load, very light load, medium load, rated load and instantaneous overload.

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