Motor stall detection method and apparatus, electronic speed controller

Abstract

The application discloses a motor stall detection method and device and an electronic speed regulator, relates to the technical field of motor fault identification, and discloses the motor stall detection method and device and the electronic speed regulator, which judges the stall state by comprehensively considering the multidimensional parameters of motor input power, rotating speed and efficiency, and effectively solves the problems of high false alarm rate and poor adaptability of traditional single parameter detection by combining a dynamic threshold adjustment and a temperature compensation mechanism, so that the detection precision is effectively improved, the risk of thermal damage is reduced, and the service life of equipment is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor fault recognition, and particularly relates to a motor stall detection method and device and an electronic speed regulator. BACKGROUND

[0002] Motor stall is a common fault phenomenon in the field of motor control, which refers to the situation that the rotor cannot rotate or the rotation speed is abnormally reduced due to excessive load or mechanical jamming of the motor, while the electronic speed regulation system is still in a state of continuous power supply. This abnormal working condition can instantaneously generate an electric current several times the rated value, resulting in a large amount of heat energy accumulated in the motor winding and power device of the electronic speed regulator in a short time. If timely detection and protective measures are not taken, irreversible damage such as demagnetization of permanent magnets, damage of winding insulation or burning of power devices can easily occur.

[0003] The current mainstream stall protection scheme is mainly based on a single parameter threshold judgment mechanism, including two typical implementation methods of current detection method and rotation speed detection method. The current detection method detects the current value of the DC bus or the power device branch, and triggers protection when the detected current value exceeds the preset threshold and lasts for a specified time. The rotation speed detection method relies on the rotation speed signal obtained by the Hall sensor or back electromotive force estimation, and determines stall when the throttle command and the measured rotation speed are seriously mismatched. The above detection schemes are difficult to accurately distinguish between stall and normal working conditions (such as motor starting, sudden load increase, etc.), and in order to reduce the false alarm rate, the protection delay time has to be extended, which further aggravates the risk of thermal damage to the equipment.

[0004] The above content is only used to assist in understanding the technical solutions of the present application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a motor stall detection method and device and an electronic speed regulator, which aims to improve the accuracy of motor stall detection.

[0006] To achieve the above purpose, the present application provides a motor stall detection method, which comprises:

[0007] obtaining the DC bus voltage and the DC bus current of the motor, and calculating based on the DC bus voltage and the DC bus current to obtain the input power of the motor;

[0008] obtaining the torque current component and the rotation speed of the motor, and calculating based on the torque current component, the rotation speed of the motor and the preset torque constant to obtain the mechanical power of the motor;

[0009] calculating based on the mechanical power of the motor and the input power of the motor to obtain the efficiency of the motor;

[0010] When the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, the motor efficiency is lower than a preset efficiency value, and the duration reaches a preset time length, it is determined that the motor is stalled.

[0011] In an embodiment, the step of acquiring the DC bus voltage and the DC bus current of the motor comprises:

[0012] The original voltage signal is collected by a voltage sensor, and the original voltage signal is subjected to mean value filtering processing to acquire the DC bus voltage;

[0013] The original current signal is collected by a current sensor, and the original current signal is subjected to sliding window filtering processing to acquire the DC bus current.

[0014] In an embodiment, the step of calculating based on the DC bus voltage and the DC bus current to acquire the motor input power comprises:

[0015] The DC bus voltage and the DC bus current are multiplied to obtain instantaneous power data;

[0016] The instantaneous power data is subjected to time integration operation to generate cumulative energy data in a preset period;

[0017] The cumulative energy data is divided by the current period to acquire the motor input power.

[0018] In an embodiment, the step of determining that the motor is stalled when the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, and the motor efficiency is lower than a preset efficiency value, and the duration reaches a preset time length comprises:

[0019] When the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, and the motor efficiency is lower than a preset efficiency value, a timer is started;

[0020] After the timer is started, it is detected in real time whether the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, and the motor efficiency is lower than a preset efficiency value, and if at least one of them is not satisfied, the timer is reset;

[0021] When the cumulative value of the timer reaches a preset time length, a stall confirmation flag is generated to determine that the motor is stalled.

[0022] In an embodiment, the method further comprises:

[0023] Based on the model parameters of the motor, an initial value of the torque constant is extracted;

[0024] acquire a motor running temperature, and compensate and correct the initial value of the torque constant according to the motor running temperature to acquire the preset torque constant.

[0025] In an embodiment, after determining that the motor is stalled, the method further comprises:

[0026] acquiring a motor real-time temperature;

[0027] when the motor real-time temperature exceeds a safety threshold, triggering a motor power-off protection mechanism;

[0028] when the motor real-time temperature does not exceed the safety threshold, periodically reducing the driving current of the motor and detecting the change of the motor rotating speed, and when it is detected that the motor rotating speed continuously rises and exceeds a preset recovery threshold, generating a stall removal signal to recover the driving current of the motor.

[0029] In an embodiment, the method further comprises:

[0030] continuously recording the motor efficiency and constructing a historical efficiency dataset;

[0031] performing a sliding variance calculation on the historical efficiency dataset to acquire an efficiency variance value;

[0032] when the efficiency variance value continuously exceeds a preset warning range, generating a bearing wear warning signal.

[0033] In an embodiment, before the step of determining that the motor is stalled, the method further comprises:

[0034] determining a current working condition of the motor;

[0035] increasing the preset efficiency value when the motor is in a heavy load working condition, and decreasing the preset efficiency value when the motor is in an idle load working condition.

[0036] In addition, to achieve the above-mentioned purposes, the present application further provides a motor stall detection device, which comprises a memory, a processor, and a motor stall detection program stored in the memory and executable on the processor, and the motor stall detection program is configured to implement the steps of the motor stall detection method.

[0037] In addition, to achieve the above-mentioned purposes, the present application further provides an electronic speed regulator, which uses the motor stall detection method, or the electronic speed regulator comprises the motor stall detection device.

[0038] The motor stall detection method and device and electronic speed regulator provided by the application can effectively solve the problems of high false alarm rate and poor adaptability of traditional single parameter detection by comprehensively judging the stall state of the motor through multi-dimensional parameters of motor input power, rotating speed and efficiency, and combining dynamic threshold adjustment and temperature compensation mechanism, and can effectively improve detection accuracy, reduce the risk of thermal damage and prolong the service life of the device. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the application and, together with the description, further serve to explain the principles of the application.

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without creative labor.

[0041] Figure 1 A flowchart is provided for an embodiment of the motor stall detection method of the application;

[0042] Figure 2 A detailed flowchart is provided for step S100 in the application Figure 1

[0043] Figure 3 A detailed flowchart is provided for step S400 in the application Figure 1

[0044] A flowchart is provided for another embodiment of the motor stall detection method of the application; Figure 4

[0045] A flowchart is provided for another embodiment of the motor stall detection method of the application; Figure 5

[0046] A flowchart is provided for another embodiment of the motor stall detection method of the application; Figure 6

[0047] A flowchart is provided for another embodiment of the motor stall detection method of the application; Figure 7 A structural diagram is provided for an embodiment of the motor stall detection device of the application.

[0048] Explanation of reference numerals:

[0049] 10, memory; 20, processor.

[0050] The purpose of the application, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0051] ​The technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0052] It should be understood that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0053] In the prior art, motor stall detection generally uses single-dimensional criteria of current detection or rotational speed detection. When the motor starts or bears a sudden heavy load, the current will instantaneously increase, and the rotational speed can sharply decrease, at this time, the traditional detection method is easy to misjudge as a stall state. In order to reduce the false alarm rate, the prior art has to prolong the protection delay, resulting in that the motor bears a large current impact for too long when it is in a real stall state, and there is a risk of device damage.

[0054] In order to solve the above problems, the researchers found that single parameter detection cannot accurately distinguish between normal working conditions and stall states. By analyzing the energy conversion relationship of the motor when it is running, it is found that there is a significant imbalance between the input power and the mechanical power in the stall state. Based on this, input power, mechanical power and rotational speed are proposed as a collaborative criterion, and a multi-dimensional determination model is constructed combined with the efficiency parameter.

[0055] Based on this, the motor stall detection method provided in the embodiments of the present application, with reference to Figure 1 , the motor stall detection method comprises steps S100-S400, wherein:

[0056] Step S100, acquiring a direct current bus voltage and a direct current bus current of a motor, and calculating based on the direct current bus voltage and the direct current bus current to obtain a motor input power;

[0057] Step S200, acquiring a torque current component and a motor rotational speed, and calculating based on the torque current component, the motor rotational speed and a preset torque constant to obtain a motor mechanical power;

[0058] Step S300, calculating based on the motor mechanical power and the motor input power to obtain a motor efficiency;

[0059] Step S400, when the motor input power is greater than the preset power value, the motor speed is lower than the preset speed value, and the motor efficiency is lower than the preset efficiency value are satisfied at the same time, and the duration reaches the preset time length, it is determined that the motor is locked.

[0060] In this embodiment, the DC bus voltage refers to the voltage across the DC power supply in the motor drive circuit, which can be obtained by collecting the original signal through a voltage sensor and then performing mean filtering processing, and is used to reflect the input level of electrical energy. The DC bus current refers to the total current flowing through the motor drive circuit, which can be obtained by collecting the original signal through a current sensor and then performing sliding window filtering processing, and is used to calculate the instantaneous power. The torque current component refers to the current component in the motor control system for generating electromagnetic torque, which can be obtained directly through an electronic governor. The preset torque constant refers to the torque value corresponding to a unit torque current component, which can be calibrated according to motor parameters, and is used to calculate mechanical power. The preset efficiency value refers to the minimum ratio of mechanical power to input power under normal operation, which can be dynamically adjusted according to the type of motor, and is used to identify energy conversion abnormalities.

[0061] In this embodiment, the input power is obtained by real-time monitoring the product of the DC bus voltage and current, reflecting the total amount of electrical energy consumption. At the same time, the mechanical power is obtained by multiplying the product of the torque current component and the speed by the torque constant, representing the effective output energy. The efficiency parameter is obtained by calculating the ratio of the two, reflecting the energy conversion efficiency. When the input power abnormally rises, the speed suddenly drops, and the efficiency is lower than the threshold value, the duration condition is combined to comprehensively determine the locked state. This determination mechanism can effectively filter the current impact at the moment of starting, and distinguish between heavy load conditions and real locked state.

[0062] In this embodiment, the energy conversion efficiency criterion is constructed by introducing the efficiency parameter, and the multi-dimensional cooperative detection of power and speed is combined to establish a locked rotor determination model from the perspective of energy conservation, which can significantly reduce the probability of false triggering and avoid protection misoperation caused by normal starting or short-term overload. At the same time, the energy conversion efficiency is dynamically monitored through the efficiency parameter, which can quickly identify the real locked state, and improve the system reliability on the premise of ensuring detection sensitivity.

[0063] In a feasible implementation manner, the step of obtaining the DC bus voltage and the DC bus current of the motor comprises: collecting an original voltage signal through a voltage sensor, and performing mean filtering processing on the original voltage signal to obtain the DC bus voltage; collecting an original current signal through a current sensor, and performing sliding window filtering processing on the original current signal to obtain the DC bus current.

[0064] In this embodiment, the mean filtering process refers to the arithmetic mean operation on multiple continuous sampling values collected by the voltage sensor. Specifically, it can be implemented by collecting ten voltage sampling values within a fixed period and calculating their average value, thereby eliminating high-frequency random noise and improving the stability of the voltage signal. The sliding window filtering process refers to the statistical quantity calculation on the continuous data stream collected by the current sensor within a fixed window length. Specifically, it can be implemented by constructing a window with every five adjacent current sampling values and calculating their moving average value, thereby suppressing transient fluctuations and retaining the dynamic change trend of the current.

[0065] In this embodiment, the high-frequency noise in the voltage signal mainly comes from electromagnetic interference or sensor errors. After the mean filtering process, the abnormal peaks in the voltage signal are smoothed, for example, the voltage jitter generated at the moment of motor start-up can be corrected by the average value of multiple sampling points. The fluctuations in the current signal are mainly caused by load mutation or commutation process. The sliding window filtering process retains the change direction of the current while limiting the mutation amplitude of adjacent sampling values within the window range. For example, when the motor suddenly accelerates and causes the current to increase sharply, the moving average of multiple sampling values within the window can avoid distortion caused by single-point sampling abnormalities. Therefore, the voltage and current signals are respectively subjected to targeted filtering processing, providing accurate input data for subsequent power calculation.

[0066] In this embodiment, different filtering strategies are designed for the high-frequency noise of the voltage signal and the transient fluctuations of the current signal, respectively, which eliminates random noise in the voltage signal while retaining effective change information in the current signal, avoids signal distortion or response delay caused by a single filtering method, suppresses noise interference in the DC bus voltage and current signals, and solves the problem of stall misjudgment caused by signal distortion. The mean filtering process of the voltage signal reduces the influence of instantaneous voltage abnormalities on input power calculation, and the sliding window filtering process of the current signal avoids distortion of the current sampling value caused by load mutation. The combination of the two ensures the accurate acquisition of motor input power and mechanical power, thereby improving the reliability of stall detection.

[0067] In a feasible implementation manner, referring to Figure 2 , the step of calculating based on the DC bus voltage and the DC bus current to obtain the motor input power includes steps S110-S130, wherein:

[0068] Step S110, multiplying the DC bus voltage and the DC bus current to obtain instantaneous power data;

[0069] Step S120, performing time integration operation on the instantaneous power data to generate accumulated energy data within a preset period;

[0070] Step S130, dividing the accumulated energy data by the current period to obtain the motor input power.

[0071] In this embodiment, the time integration operation refers to the accumulation and summation of instantaneous power data in continuous time, which can be implemented by using trapezoidal integration or rectangular integration. The discrete power data is converted into continuous energy accumulation by the integration operation. The preset period refers to the time window for calculating the average power, which can be set to an integer multiple of 50 milliseconds to 200 milliseconds, for example, 100 milliseconds. The period average processing is achieved by dividing the power data. The period average processing refers to dividing the accumulated energy data by the corresponding time window length, which can be implemented by using floating point division operation. The average operation eliminates short-term noise interference.

[0072] In this embodiment, during the operation of the motor, the instantaneous product of the DC bus voltage and current reflects the transient power, but the value is easily affected by motor commutation noise or sensor sampling error. The discrete power points are accumulated by time integration operation to form an energy accumulation curve. The curve has continuity in time dimension, which can effectively suppress the abnormal fluctuation of a single sampling point. For example, in a 100 millisecond period, power data is collected every 1 millisecond and integrated and accumulated. The average power value is obtained by dividing the total energy by 0.1 seconds. This processing method not only retains the overall trend of power change, but also eliminates high-frequency interference components through the smoothing characteristics of the integration operation. The period average establishes a statistically stable power index.

[0073] In this embodiment, the energy accumulation model is constructed by integration operation, the transient power fluctuation is converted into continuous change of energy accumulation, and the statistically significant power index is obtained by period average processing, which effectively distinguishes the instantaneous fluctuation of normal working condition from the continuous abnormality of locked-rotor state. For example, the short-time power peak value during the acceleration stage of the motor is diluted after integration and average processing, while the continuous high power state during locked-rotor is accurately captured. In this way, the present application can eliminate the instantaneous power peak interference caused by motor commutation noise, sensor sampling error or load mutation, and accurately calculate the average value of motor input power. The technical scheme realizes the time domain correlation and statistical stability of power data by double processing of energy accumulation and period average, establishes a reliable power calculation benchmark for subsequent locked-rotor judgment under the premise of ensuring real-time, and solves the misjudgment problem caused by simply relying on current or speed threshold detection in the prior art.

[0074] In one possible implementation, the reference Figure 3 Step S400 includes steps S410-S430, in which:

[0075] Step S410, when the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, and the motor efficiency is lower than a preset efficiency value, start the timer.

[0076] Step S420, detecting in real time whether the motor input power is greater than a preset power value, the motor speed is lower than a preset speed value, and the motor efficiency is lower than a preset efficiency value after the timer is started, and resetting the timer if at least one of the conditions is not met;

[0077] Step S430, generating a locked-rotor confirmation flag when the accumulated value of the timer reaches a preset time length, to determine the locked-rotor of the motor.

[0078] In this embodiment, starting the timer means triggering the time accumulation mechanism when the motor input power, speed and efficiency simultaneously exceed the set threshold, which can be implemented by the timer module of the microcontroller, for quantifying the duration of the abnormal state. Real-time detection means continuously collecting parameter data and making logical judgments during the timing process, which can be implemented by the interrupt service program or polling method to ensure dynamic monitoring of the parameter state. Resetting the timer means clearing the accumulated time value when any parameter returns to the normal range, which can be implemented by setting the timer counter to zero to avoid false positives caused by temporary abnormalities. Generating a locked-rotor confirmation flag means outputting a state identifier when the timer reaches the preset time length, which can be implemented by using register flag bits or digital signal output to trigger subsequent protection actions.

[0079] In this embodiment, when the motor input power, speed and efficiency simultaneously exceed the threshold, the timer starts to accumulate time. During the operation of the timer, real-time detection is continuously performed on the three parameters: if any parameter returns to the normal range, the timer is immediately reset to zero; if the three parameters continue to be abnormal until the accumulated time of the timer reaches the preset time length, a locked-rotor confirmation flag is generated. In this process, the start and reset mechanisms of the timer distinguish between short-term fluctuations and persistent abnormal states, for example, a temporary power surge during motor startup or a short-term speed drop caused by load mutation, which will cause the timer to reset due to the recovery of parameters, while the real locked-rotor state is characterized by persistent abnormalities in the three parameters.

[0080] In this embodiment, the time dimension is dynamically associated with the parameter state by joint judgment of multiple parameters and dynamic timer linkage, which not only eliminates short-term abnormal interference, but also avoids the response lag caused by fixed delay, solves the problem of false triggering of protection caused by instantaneous working condition fluctuations in existing locked-rotor detection methods, and avoids the response lag or equipment damage risk caused by simply relying on the delay mechanism.

[0081] In one possible implementation, with reference to Figure 4 , the method further includes steps S510-S520, in which:

[0082] Step S510, extracting a torque constant initial value based on the model parameters of the motor;

[0083] Step S520, acquiring the motor operating temperature, and compensating and correcting the torque constant initial value according to the motor operating temperature to obtain the preset torque constant.

[0084] In this embodiment, the model parameter refers to a set of inherent parameters calibrated when the motor is shipped, which can be realized by using the motor nameplate data or the parameters recorded in the technical manual provided by the manufacturer, and is used to determine the initial reference value of the torque constant. The torque constant initial value refers to the theoretical torque value generated by unit current of the motor under standard temperature conditions, which can be realized by analyzing the motor electromagnetic design parameters or experimental calibration data, and provides a reference for subsequent temperature compensation. The motor operating temperature refers to the real-time temperature data generated by the motor winding or magnet during operation, which can be realized by using a thermocouple, a thermistor or an infrared sensor to collect temperature signals, and is used to reflect the influence of temperature change on the torque constant. The compensation and correction refer to the process of dynamically adjusting the torque constant initial value according to the temperature change, which can be realized by constructing a temperature-torque correction coefficient mapping table and matching the compensation parameters corresponding to the real-time temperature by using the look-up table method, and is used to offset the torque constant deviation caused by the magnetic flux decay or winding resistance change due to temperature.

[0085] In this embodiment, the torque constant initial value is first extracted from the motor model parameter, which corresponds to the theoretical performance parameter of the motor at room temperature. Then, the motor operating temperature is collected in real time by a temperature sensor, and the temperature is input into the pre-established temperature-torque correction coefficient mapping table to match the compensation parameters corresponding to the current temperature interval. The compensation parameters are set according to the material thermal expansion coefficient, magnetic flux temperature characteristics and other physical laws, for example, a negative compensation coefficient is used in the high temperature interval to reflect the magnetic flux decay effect. Finally, the torque constant initial value is multiplied by the compensation parameter to generate a dynamically corrected torque constant, which is used for subsequent mechanical power calculation. This process realizes double calibration mechanism, which not only retains the accuracy of the original design parameters of the motor, but also realizes dynamic adaptation under temperature change.

[0086] In this embodiment, by introducing the temperature compensation mechanism, the correlation between temperature and torque constant is established based on physical characteristics, the look-up table method is used to realize low-delay dynamic parameter correction, which effectively eliminates the influence of temperature change on calculation accuracy, solves the mechanical power calculation error problem caused by torque constant deviation due to temperature change, avoids the mis-triggering or missed detection phenomenon caused by inaccurate mechanical power calculation in the process of locked-rotor detection, and improves the reliability of locked-rotor detection.

[0087] In a possible implementation, with reference to Figure 5 , the method further includes steps S610-S620, wherein:

[0088] Step S610, acquiring the motor real-time temperature;

[0089] Step S620, when the motor real-time temperature exceeds the safety threshold, triggering the motor power-off protection mechanism; when the motor real-time temperature does not exceed the safety threshold, periodically reducing the motor drive current and detecting the motor speed change, and generating a locked-rotor release signal to restore the motor drive current when the motor speed is detected to continuously rise and exceed a preset recovery threshold.

[0090] In this embodiment, the motor real-time temperature refers to the instantaneous temperature data of the motor winding or shell, which can be collected by a surface-mounted thermocouple or an infrared temperature sensor, and is used to evaluate the heat accumulation state of the motor during operation. The safety threshold refers to the preset temperature limit of the motor material, which can be set to 130℃ or 155℃ according to the motor insulation level, and is used to trigger emergency power-off to avoid thermal runaway. Periodic reduction of drive current refers to gradually reducing the output control of PWM duty cycle at fixed time intervals, which can use a stepwise decreasing strategy, and the reduction amplitude can be set to 5% to 10% of the current value, which is used to alleviate the energy input under locked-rotor condition. The preset recovery threshold refers to the speed threshold for determining that the motor is out of locked-rotor state, which can be set to 20% to 30% of the rated speed, and is used to identify the working condition that the mechanical load is reduced or the locked-rotor obstacle is eliminated.

[0091] In this embodiment, when the motor is determined to be locked-rotor, the temperature monitoring module immediately starts real-time sampling. If it is detected that the temperature exceeds the safety threshold, the main controller directly cuts off the power supply of the three-phase inverter bridge, and forces the system to enter the shutdown state. If the temperature is within the safety range, the drive current is gradually attenuated at a fixed period, and the motor speed is continuously monitored. When it is detected that the speed exceeds the recovery threshold for three consecutive sampling periods, it is determined that the locked-rotor state is released, and the drive current is restored to the normal value according to the preset slope. In this process, the temperature data and current regulation form a closed-loop control, which not only prevents overheating damage but also maintains the system operation capability.

[0092] In this embodiment, by introducing the cooperative mechanism of temperature monitoring and dynamic current regulation, the system self-recovery capability is retained under the premise of ensuring thermal safety. The problem of manual reset after current sudden drop in the prior art is solved in this scheme by automatically releasing the protection state through speed feedback, realizing unattended intelligent recovery. Through the above technical scheme, the contradiction between safety and availability in the locked-rotor protection process is effectively solved. Through the hierarchical protection mechanism triggered by temperature, the system can be powered off in time to prevent equipment from burning out under extreme working conditions, and the system operation can be maintained and automatically recovered within a controllable temperature range. The periodic current regulation combined with the speed feedback mechanism avoids the misoperation or response lag caused by fixed time delay in the traditional scheme, significantly improving the reliability and self-adaptive ability of the protection system.

[0093] In a feasible implementation manner, referring to Figure 6 , the method further includes steps S710-S730, wherein:

[0094] Step S710, continuously record the motor efficiency and build a historical efficiency dataset;

[0095] Step S720, perform a sliding variance calculation on the historical efficiency dataset to obtain an efficiency variance value;

[0096] Step S730, when the efficiency variance value continuously exceeds a preset warning range, generate a bearing wear warning signal.

[0097] In this embodiment, the historical efficiency dataset refers to a time series data set formed by periodically sampling and storing motor efficiency values, which can be implemented using a ring buffer or a database table structure, and is used to reflect the long-term trend of motor operating efficiency. The sliding variance calculation refers to performing variance operation on a fixed length of continuous sample segment in the dataset, which can be implemented using a moving window algorithm, and the influence of transient interference on the statistical result is eliminated by dynamically updating the data in the window. The preset warning range refers to the reasonable interval of variance fluctuation set according to the motor model and working condition, which can be determined by experiment calibration or historical data analysis, and is used to distinguish between normal fluctuation and abnormal fluctuation.

[0098] In this embodiment, the motor efficiency value is periodically collected and stored in the historical dataset to form an efficiency change record containing multiple time points. The sliding variance calculation module traverses the dataset with a fixed window length, calculates the variance of the efficiency values in the window each time, and generates a numerical sequence reflecting the degree of efficiency fluctuation. When the continuous multiple variance calculation results exceed the preset threshold interval, it is determined that there is a gradual mechanical loss feature, and a bearing wear warning signal is triggered. This continuous overrun judgment mechanism can effectively filter incidental interference and accurately capture the efficiency fluctuation anomaly caused by bearing wear.

[0099] It can be understood that the existing locked-rotor detection method only relies on the instantaneous value of current or speed for judgment, and cannot identify the gradual decline in efficiency caused by bearing wear. The present scheme can detect mechanical component abnormalities in advance by analyzing the continuous change trend of the efficiency variance value, and realize fault warning before locked-rotor occurs. The traditional method cannot generate a warning signal at the early stage of bearing wear due to the lack of efficiency fluctuation monitoring mechanism, resulting in misjudgment of locked-rotor or sudden failure. The present application can monitor the efficiency fluctuation characteristics in real time during motor operation, trigger a warning signal before the bearing is severely worn, and enable maintenance personnel to perform preventive maintenance in a timely manner. This effectively avoids the problem of misjudgment of locked-rotor caused by unrecognized mechanical component abnormalities, and reduces the risk of equipment damage caused by sudden mechanical failure.

[0100] In a feasible implementation, before step S400, the method further comprises: determining the current working condition of the motor; increasing the preset efficiency value when the motor is in a heavy load working condition, and decreasing the preset efficiency value when the motor is in an idle working condition.

[0101] In this embodiment, the current working condition of the motor is determined by real-time monitoring of the operating parameters of the motor to determine the load state, and specifically, the ratio of current to speed can be used for analysis. When the current significantly increases while the speed does not synchronously rise, it is determined as a heavy load condition, and when the current is at a low level and the speed fluctuates little, it is determined as an empty load condition. Increasing the preset efficiency value means adjusting the efficiency determination threshold upward under heavy load conditions, which can be dynamically set by table lookup or linear interpolation according to the load level. Reducing the preset efficiency value means adjusting the efficiency determination threshold downward under no-load conditions, which can be scaled by a preset proportion factor on the reference threshold, so that the efficiency fluctuation at low power operation will not trigger a false judgment.

[0102] In this embodiment, during the operation of the motor, the load rate is first calculated by collecting current and speed data, and the heavy or empty load state is divided according to the interval of the load rate. When it is identified as a heavy load condition, the efficiency determination threshold is increased by a certain amplitude based on the preset compensation coefficient, for example, the original threshold is multiplied by 1.2 times, so that in the normal condition of increased mechanical power demand, the efficiency will not be temporarily reduced to misjudge the stall. When it is identified as an empty load condition, the efficiency threshold is reduced using a reverse compensation mechanism, for example, the original threshold is multiplied by 0.8 times, to ensure that the abnormal efficiency decrease can still be effectively captured under low load operation state. This dynamic threshold adjustment mechanism complements the fixed threshold scheme, so that the three conditions of stall determination can automatically match the best parameter combination according to the actual working condition.

[0103] In this embodiment, the dynamic mapping relationship between the load state and the efficiency threshold is established through working condition perception, solving the problem of insufficient adaptability of the fixed threshold, so that the stall detection conditions can be automatically optimized according to the actual working state of the motor. In the heavy load condition, the threshold is increased to avoid misjudging the normal high-power operation as stall, and in the empty load condition, the threshold is reduced to enhance the detection sensitivity in the low-power state, significantly improving the stall detection accuracy under different load conditions.

[0104] In this embodiment, the motor stall detection method determines the stall state by comprehensively considering the multi-dimensional parameters of motor input power, speed and efficiency, and combines dynamic threshold adjustment and temperature compensation mechanism, effectively solving the problem of high false alarm rate and poor adaptability of traditional single parameter detection. It not only effectively improves the detection accuracy, but also reduces the risk of thermal damage and prolongs the service life of the equipment.

[0105] It should be noted that the above examples are only for understanding the present application and do not limit the motor stall detection method of the present application. Based on this technical concept, more forms of simple transformation are within the protection scope of the present application.

[0106] The present application also provides a motor stall detection device, which is described with reference to Figure 7The motor stall detection device comprises a memory 10, a processor 20 and a motor stall detection program stored in the memory 10 and executable on the processor 20, and the motor stall detection program is configured to implement the steps of the motor stall detection method.

[0107] The motor stall detection device provided by the application can improve the accuracy of motor stall detection by using the motor stall detection method in the above embodiment. Compared with the prior art, the motor stall detection device provided by the application has the same beneficial effects as the motor stall detection method provided by the above embodiment, and other technical features in the motor stall detection device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0108] The application also provides an electronic speed regulator, which uses the motor stall detection method or comprises the motor stall detection device.

[0109] The electronic speed regulator in the embodiment can improve the accuracy of motor stall detection by using the motor stall detection method or comprising the motor stall detection device. Compared with the prior art, the electronic speed regulator provided by the application has the same beneficial effects as the motor stall detection method and the motor stall detection device provided by the above embodiment, and other technical features in the electronic speed regulator are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0110] It should be understood that various parts of the application can be realized by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0111] The above is only a specific implementation of the application, but the protection scope of the application is not limited thereto, and any equivalent structural transformation made by using the content of the application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A method of detecting a locked-rotor condition of an electric machine, the method comprising: The motor stall detection method comprises: Obtaining the DC bus voltage and the DC bus current of the motor, and calculating based on the DC bus voltage and the DC bus current to obtain the motor input power; Obtaining the torque current component and the motor speed, and calculating based on the torque current component, the motor speed and the preset torque constant to obtain the motor mechanical power; Calculating based on the motor mechanical power and the motor input power to obtain the motor efficiency; When the motor input power is greater than the preset power value, the motor speed is lower than the preset speed value, and the motor efficiency is lower than the preset efficiency value are simultaneously satisfied, and the duration reaches the preset time length, it is determined that the motor is stalled.

2. The motor stall detection method of claim 1, wherein, The step of obtaining the DC bus voltage and the DC bus current of the motor comprises: Collecting the original voltage signal through the voltage sensor, and performing mean value filtering processing on the original voltage signal to obtain the DC bus voltage; Collecting the original current signal through the current sensor, and performing sliding window filtering processing on the original current signal to obtain the DC bus current.

3. The motor stall detection method of claim 1, wherein, The step of calculating based on the DC bus voltage and the DC bus current to obtain the motor input power comprises: Multiplying the DC bus voltage and the DC bus current to obtain instantaneous power data; Performing time integration operation on the instantaneous power data to generate cumulative energy data within a preset period; Dividing the cumulative energy data by the current period to obtain the motor input power.

4. The motor stall detection method of claim 1, wherein, The step of determining that the motor is stalled when the motor input power is greater than the preset power value, the motor speed is lower than the preset speed value, and the motor efficiency is lower than the preset efficiency value are simultaneously satisfied, and the duration reaches the preset time length comprises: When the motor input power is greater than the preset power value, the motor speed is lower than the preset speed value, and the motor efficiency is lower than the preset efficiency value are simultaneously satisfied, start the timer; After the timer is started, it is detected in real time whether the motor input power is greater than the preset power value, the motor speed is lower than the preset speed value, and the motor efficiency is lower than the preset efficiency value are simultaneously satisfied, if at least one of them is not satisfied, reset the timer; When the cumulative value of the timer reaches the preset time length, generate a stall confirmation flag to determine that the motor is stalled.

5. The method of claim 1, wherein, The method further comprises: Based on the model parameters of the motor, extract the initial value of the torque constant; Obtain the motor operating temperature, and compensate and correct the initial value of the torque constant according to the motor operating temperature to obtain the preset torque constant.

6. The motor stall detection method of claim 1, wherein, After determining that the motor is stalled, the method further comprises: Obtaining the real-time temperature of the motor; When the real-time temperature of the motor exceeds the safety threshold, triggering the motor power-off protection mechanism; When the real-time temperature of the motor does not exceed the safety threshold, periodically reducing the drive current of the motor and detecting the change of the motor speed, and when the motor speed continuously rises and exceeds the preset recovery threshold, generating a stall removal signal to restore the drive current of the motor.

7. The motor stall detection method of claim 1, wherein, The method further comprises: Continuously record the motor efficiency and build a historical efficiency dataset; Performing sliding variance calculation on the historical efficiency dataset to obtain the efficiency variance value; When the efficiency variance value continuously exceeds the preset early warning range, a bearing wear early warning signal is generated.

8. The motor stall detection method of claim 1, wherein, Before the step of determining that the motor is in a locked-rotor state when the motor input power is greater than a preset power value, the motor rotating speed is lower than a preset rotating speed value, and the motor efficiency is lower than a preset efficiency value, and the duration reaches a preset time length, the method further comprises: Determining a current working condition of the motor; Increasing the preset efficiency value when the motor is in a heavy load working condition, and decreasing the preset efficiency value when the motor is in an idle load working condition.

9. A motor stall detection device, characterized by, The motor locked-rotor detection device comprises a memory, a processor, and a motor locked-rotor detection program stored in the memory and capable of running on the processor, and the motor locked-rotor detection program is configured to implement the steps of the motor locked-rotor detection method according to any one of claims 1 to 8.

10. An electronic speed controller characterized by The electronic speed regulator uses the motor locked-rotor detection method according to any one of claims 1 to 8, or the electronic speed regulator comprises the motor locked-rotor detection device according to claim 9.

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