A motor overload protection method and device, electronic equipment and storage medium

Abstract

The application discloses a motor overload protection method and device, electronic equipment and storage medium, relates to the technical field of servo control, and comprises the following steps: acquiring a real-time current of a motor, determining a proportion of a current relative to a rated current, and performing heat accumulation timing according to the current proportion; based on a preset data set, querying an overload allowed time or a heat dissipation deduction time of the current proportion, wherein the preset data set comprises an overload allowed time of different current proportions in normal operation, an overload allowed time of different current proportions in locked-rotor operation and a heat dissipation deduction time; comparing the heat accumulation timing with the overload allowed time, and triggering the overload protection when the heat accumulation timing reaches the allowed overload time. It is suitable for resource-restricted embedded hardware, adapts to the heat dissipation characteristics of the motor under different working conditions, and realizes fine and scenario-based protection of motor overload.

Description

Technical Field

[0001] This invention belongs to the field of motor overload technology, and particularly relates to a motor overload protection method, device, electronic device and storage medium. Background Technology

[0002] In servo motor drive systems, thermal protection for the motor and driver is a crucial safety mechanism. During motor operation, current flowing through the windings generates heat (IT). 2 (R loss) If the current is too high or the duration is too long, it will cause the motor windings to overheat, leading to insulation aging, short circuits, or even burnout. Simultaneously, the power devices (IGBT / MOSFET) in the driver will also be damaged by overheating, and overheating of the regenerative resistor may also pose a fire hazard. Therefore, effective overload protection for the motor system is essential. However, motors are not incapable of withstanding any overload. In practice, motors have short-term overload capacity, allowing them to output torque exceeding the rated current for a certain period, based on the rated current. In industrial applications such as conveyor systems with frequent start-stop cycles and robotic arms with sudden load increases, fully utilizing this short-term overload capacity can improve the system's dynamic response and load-carrying capacity. Therefore, an ideal overload protection method should maximize the motor's overload potential while ensuring safety.

[0003] Currently, motor overload protection mainly employs the following technical solutions. One is the fixed threshold protection method, which sets a fixed current threshold; once the current exceeds this threshold, the protection action is immediately triggered. The second is the traditional I... 2 The T-method is a continuous integration method that calculates the integral of the square of the current over time in real time. The integral value increases when the current exceeds the rated value and decreases when it falls below the rated value. The protection is triggered by comparing the integral value with a set threshold. The third method is a temperature sensor-based protection method. This method directly measures the temperature by installing a temperature sensor on the motor windings or power devices. Protection is triggered when the temperature exceeds a set threshold.

[0004] However, the fixed threshold protection method does not allow the use of the motor's short-term overload capacity, causing the system to trip frequently in scenarios requiring short-term high torque output, thus limiting system performance. Traditional I 2The T-continuous integration method requires real-time squaring, integration accumulation, and threshold comparison, resulting in a large computational load and placing a significant burden on low-cost MCUs / DSPs, potentially affecting the real-time performance of the control system. Most of the methods mentioned above assume the motor is in normal operating condition, using the same set of protection curves or parameters regardless of whether the motor is running normally or stalled. They fail to consider the fact that the fan stops and cooling conditions deteriorate drastically when stalled. If the overload curve for normal operation is used, the allowable time may be too long, potentially causing the motor to burn out before protection is triggered. Furthermore, in existing methods, heat dissipation is often only considered as the reverse process of overload integration, without differentiating the heat dissipation rate under different light load conditions. This simplified heat dissipation model cannot accurately simulate the thermal capacity effect of the motor, leading to decreased protection accuracy. Summary of the Invention

[0005] In view of this, the present invention provides a method, device, electronic device and storage medium for motor overload protection, which solves the problems of large calculation load and inaccurate protection under operating conditions in the process of motor overload protection.

[0006] To achieve the above objectives, in a first aspect, the technical solution of the present invention to solve the technical problem is to provide a motor overload protection method, comprising: acquiring the real-time current of the motor, determining the proportion of the current current relative to the rated current, and performing thermal accumulation timing based on the current current proportion; querying the overload allowable time or heat dissipation deduction time of the current current proportion based on a preset dataset, wherein the preset dataset includes the overload allowable time during normal operation, the overload allowable time during stall, and the heat dissipation deduction time for different current proportions; comparing the thermal accumulation timing with the overload allowable time, and triggering overload protection when the thermal accumulation timing reaches the allowable overload time.

[0007] In one specific embodiment, the current percentage in the preset dataset is divided into multiple discrete intervals according to a fixed step size of the rated current, and each discrete interval corresponds to the overload allowable time or the heat dissipation deduction time.

[0008] In one specific embodiment, the step of performing thermal accumulation timing based on the current current percentage includes: increasing the accumulation time when the current current percentage is greater than or equal to a first threshold; and deducting the accumulation time when the current current percentage is less than or equal to a second threshold; wherein the first threshold is greater than the rated current and the second threshold is less than the rated current.

[0009] In one specific embodiment, there is a hysteresis interval between the first threshold and the second threshold, and when the current current percentage is between the first threshold and the second threshold, the cumulative time remains unchanged.

[0010] In one specific embodiment, when the current current percentage is greater than or equal to the first threshold, it is increased in fixed time units, and when it is less than or equal to the second threshold, it is deducted by a predetermined value related to the current current percentage, wherein the smaller the current current percentage is, the larger the predetermined value is deducted.

[0011] In one specific embodiment, when querying the overload allowable time of the current current percentage, the overload allowable time for normal operation or the overload allowable time for stalled rotor is queried according to the current operating conditions.

[0012] In one specific embodiment, the real-time current includes the actual current and the commanded current. Before executing the thermal accumulation timing, the consistency between the actual current and the commanded current is determined. The corresponding thermal accumulation timing is executed only when the ratios of the actual current and the commanded current relative to the rated current simultaneously meet the timing conditions of the corresponding operating condition. Secondly, the present invention provides a motor overload protection device, including a thermal accumulation timing module for acquiring the real-time current of the motor, determining the ratio of the current current relative to the rated current, and executing thermal accumulation timing based on the current current ratio; a parameter lookup table module for querying the overload allowable time or heat dissipation deduction time for the current current ratio based on a preset dataset, wherein the preset dataset includes the overload allowable time during normal operation, the overload allowable time during stall, and the heat dissipation deduction time for different current ratios; and an overload protection triggering module for comparing the thermal accumulation timing with the overload allowable time, and triggering overload protection when the thermal accumulation timing reaches the allowable overload time.

[0013] Thirdly, the present invention provides an electronic device comprising: an input unit, a memory, at least one processor, and an output unit, wherein the memory stores program instructions that can be executed on the processor, and the processor can execute the motor overload protection method by calling the program instructions.

[0014] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements a motor overload protection method.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: By employing a three-stage table lookup, discretized data storage, and parameter configuration differentiated by operating conditions, the traditional continuous I / O method is replaced. 2T-integral calculation significantly reduces computational load, eliminating the need for floating-point operations and real-time integration. Overload protection determination is achieved solely through simple table lookups and numerical comparisons. It is compatible with resource-constrained embedded hardware such as low-cost MCUs and fixed-point DSPs, enabling stable real-time operation in high-speed control loops. Simultaneously, a preset dataset differentiates the overload allowable time for normal operation and stall conditions, closely aligning with the motor's heat dissipation characteristics under different operating conditions. This solves the problem of inaccurate protection for stall conditions using traditional single protection curves, fully utilizing the motor's short-term overload capability while ensuring motor safety, thus improving the performance of the servo drive system. Furthermore, by matching the current ratio with the corresponding heat dissipation deduction time, the thermal capacitance effect and heat dissipation process of the motor can be accurately simulated, avoiding the protection misjudgments caused by traditional protection methods that only consider overload and ignore heat dissipation. Combined with precise comparison of thermal accumulation timing and overload allowable time to trigger protection, refined and scenario-based overload protection of the motor is achieved, effectively preventing damage to motor windings and driver power devices due to overload and overheating, thus improving the safety, reliability, and engineering practicality of the servo motor drive system. Attached Figure Description

[0016] Figure 1 This is a flowchart of the steps of the motor overload protection method provided in the first embodiment of the present invention; Figure 2 This is a flowchart illustrating a motor overload protection method. Figure 3 This is a schematic diagram of the structure of the motor overload protection device provided in the second embodiment of the present invention; Figure 4 This is a schematic diagram of the electronic device structure provided in the third embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0019] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0020] In some embodiments provided by this invention, the motor overload protection method is executed by the controller of the servo motor driver. The controller can be a fixed-point digital signal processor, a low-cost microcontroller unit, or an embedded main control chip, possessing real-time current data acquisition, logical judgment, and fast table lookup capabilities, and is integrated into the main control board of the servo motor drive system. To achieve lightweight computation for overload protection, a preset dataset adapted to the motor's thermal characteristics is pre-constructed. This dataset is obtained by combining theoretical calculations of motor thermal characteristics with offline calibration tests. Based on the actual heat accumulation and dissipation patterns under three operating conditions—normal operation, stall, and heat dissipation—the permissible overload time relationship and heat dissipation rate relationship corresponding to different current levels are constructed. Furthermore, the relevant relationships can be discretized according to a preset ratio for each current level, ultimately forming a tabular dataset. The preset dataset can be stored in the controller's non-volatile memory or in a storage medium accessible to the controller, such as the servo motor drive system's supporting storage module or external storage device. When executing the overload protection method, the controller can directly retrieve the preset dataset from the corresponding storage location.

[0021] like Figures 1 to 2 As shown, the motor overload protection method includes the following steps: S101, acquire the real-time motor current, determine the ratio of the current current to the rated current, and perform thermal accumulation timing based on the current current ratio; Real-time motor current can be obtained through a current detection module integrated into the servo motor drive system. This module can be equipped with current sampling elements such as shunt resistors, Hall current sensors, or current transformers, and works with signal conditioning circuits to filter, amplify, and linearly correct the current signal. Some integrated AD conversion units can directly output digital signals to sample and detect the three-phase or single-phase operating current during motor operation in real time, accurately obtaining the actual value of the motor's real-time current. To determine the percentage of the current current relative to the rated current, the controller can call a preset motor rated current reference value. The actual real-time motor current value collected and transmitted by the current detection module is compared with this rated current reference value to calculate the percentage of the current current relative to the motor's rated current, thus quantifying the current current load of the motor.

[0022] After obtaining the current current percentage, the controller immediately executes thermal accumulation timing based on that percentage. Thermal accumulation timing refers to the operation of adding, subtracting, or keeping the internally maintained thermal accumulation time value constant based on the motor's current state. Specifically, the controller determines whether the motor should be in overload timing, heat dissipation timing, or remain constant based on the current current percentage.

[0023] S102, based on a preset dataset, query the overload allowable time or heat dissipation deduction time of the current current percentage. The preset dataset includes the overload allowable time, overload allowable time and heat dissipation deduction time of different current percentages during normal operation, during stalled operation, and respectively. The data in the preset dataset are all based on a three-segment I model pre-constructed by combining theoretical calculations of motor thermal characteristics with offline calibration test results. 2 The T-protection curve architecture is constructed, which includes three operating condition curves: normal operation overload curve, stall overload curve, and heat dissipation curve.

[0024] The normal operation overload curve corresponds to the normal working state of the motor with air cooling, while the stalled overload curve corresponds to the special stalled state of the motor without air cooling. Both overload curves are converted into overload allowable time data corresponding to different current percentages.

[0025] The heat dissipation curves are adapted to the light-load and no-load heat dissipation operating states of the motor. First, the total cooling time required to restore the heat accumulation value to the baseline state under each current percentage is obtained through experiments or theoretical calculations. Then, this total cooling time is converted into a heat dissipation deduction time that the controller can directly use, ultimately forming heat dissipation deduction time data corresponding to different current percentages. All three curves are discretized according to a preset current classification standard to ensure that different current percentages can be accurately matched with the corresponding time parameters in the dataset, forming a dedicated dataset adapted for the controller's fast table lookup calculations.

[0026] The controller retrieves a pre-configured dataset and uses the calculated current current percentage of the motor as the retrieval basis. It then performs a precise index match in the pre-configured dataset and directly queries the overload allowable time or heat dissipation deduction time corresponding to that current percentage.

[0027] By adopting a three-segment I 2 The T-protection curve architecture forms a lookup table dataset, which can fully distinguish the thermal tolerance and heat dissipation characteristics of the motor under different operating conditions. This makes the values ​​of overload allowable time and heat dissipation deduction time more consistent with the actual working state of the motor. At the same time, the discretized lookup table method simplifies the controller's calculation logic and improves the efficiency and real-time performance of parameter acquisition.

[0028] S103 compares the thermal accumulation time with the overload allowable time, and triggers overload protection when the thermal accumulation time reaches the allowable overload time; After updating the current thermal accumulation time value and retrieving the overload allowable time corresponding to the current current percentage from the preset dataset, the controller compares the current thermal accumulation time value with the overload allowable time. If the current thermal accumulation time value has reached or exceeded the overload allowable time, it indicates that the heat accumulated inside the motor has exceeded the safety threshold. The controller immediately outputs a protection control signal and executes overload protection actions (such as cutting off the power supply to the motor's main circuit, outputting an alarm signal, or limiting the output torque) to protect the motor from overload. If the overload has not yet been reached, the current control cycle ends, and the controller continues to acquire the real-time motor current for the next cycle, repeating the above operations until overload protection is triggered.

[0029] In some implementations, the current percentage in the preset dataset is divided into multiple discrete intervals according to a fixed step size of the rated current, and each discrete interval corresponds to the overload allowable time or the heat dissipation deduction time.

[0030] A fixed step size is set based on the motor's rated current, dividing the data into multiple continuous and non-overlapping discrete intervals. Each discrete interval is independently configured with a corresponding overload allowable time or heat dissipation deduction time. This allows the controller to quickly locate the corresponding time parameter based on the current percentage interval during data matching, eliminating the need for continuous numerical calculations and simplifying table lookup logic. Preferably, the fixed step size is a preset proportion of the rated current, or multiple preset current percentage intervals.

[0031] By dividing the current percentage into discrete intervals with a fixed step size, each interval directly corresponds to the overload allowable time or the heat dissipation deduction time, so that the controller only needs to determine the interval to which the current belongs to complete a table lookup once, without the need for complex calculations and interpolation processing.

[0032] It should be noted that a larger step size can be used for the low-current heat dissipation range to reduce data storage, while a smaller step size can be used for the high-overload critical range to improve the matching accuracy of the overload allowable time. Furthermore, discrete ranges can be replaced with continuous numerical mapping tables to achieve more granular overload protection when the controller has sufficient computing resources.

[0033] In some implementations, performing thermal accumulation timing based on the current current percentage includes: When the current current percentage is greater than or equal to the first threshold, the accumulation time is increased; When the current current percentage is less than or equal to the second threshold, the accumulated time is deducted. The first threshold is greater than the rated current, and the second threshold is less than the rated current.

[0034] The first threshold, higher than the rated current, is used to determine whether the motor has entered an overload state. If the condition is met, the accumulated time is added to reflect the continuous accumulation of heat. The second threshold, lower than the rated current, is used to determine whether the motor has entered a light-load heat dissipation state. If the condition is met, the accumulated time is deducted to reflect the gradual dissipation of heat. The two thresholds are independent and their intervals do not overlap, achieving a clear boundary between overload accumulation and heat dissipation deduction.

[0035] The fixed threshold can be replaced with a dynamic threshold related to the motor temperature. The controller adaptively adjusts the size of the first threshold and the second threshold according to the real-time detected motor housing temperature or winding temperature. When the temperature is too high, the overload threshold is lowered and the heat dissipation threshold is raised to accelerate the heat accumulation response speed; when the temperature is too low, the threshold range is widened to balance protection accuracy and operation continuity.

[0036] In some implementations, there is a hysteresis interval between the first threshold and the second threshold, and the cumulative time remains unchanged when the current percentage is between the first threshold and the second threshold.

[0037] When the current percentage falls within the hysteresis range, the thermal accumulation timer neither increases nor decreases, maintaining the value of the previous cycle unchanged. This avoids control jitter caused by frequent switching of the accumulation and deduction logic when the current fluctuates slightly near the threshold.

[0038] In a specific example, when the real-time current ratio is between the first threshold and the second threshold, the cumulative timing remains unchanged. By setting the hysteresis interval, the current sampling noise and frequent threshold crossings caused by slight load fluctuations are effectively filtered out, avoiding frequent switching of the thermal accumulation timing between the accumulation and subtraction states, improving the stability and reliability of the control process, while not increasing complex calculations and ensuring the controller's execution efficiency.

[0039] The hysteresis range width can be dynamically adjusted according to the motor's operating conditions. In high-speed, high-dynamic-response applications, the hysteresis range can be narrowed to improve protection sensitivity. In heavy-load, impact-load applications, the hysteresis range can be widened to further enhance anti-interference capabilities, balancing protection reliability and operational continuity.

[0040] In some implementations, when the current current percentage is greater than or equal to the first threshold, it is increased in fixed time units, and when it is less than or equal to the second threshold, it is deducted by a predetermined value related to the current current percentage, wherein the smaller the current current percentage, the larger the predetermined value to be deducted.

[0041] When the current percentage is greater than or equal to the first threshold, the motor is in an overload state. Using a fixed step size for accumulation ensures that the heat accumulation process is simple, stable, and predictable. When the current percentage is less than the second threshold, the motor is in a heat dissipation state. The lower the current percentage, the faster the heat dissipation, and the larger the corresponding single deduction value, making the heat accumulation decay law more consistent with the actual physical heat dissipation characteristics of the motor.

[0042] In some implementations, when querying the overload allowable time of the current current percentage, the overload allowable time for normal operation or stall overload is queried according to the current operating conditions.

[0043] After obtaining the current current percentage, the controller does not directly use a single overload time parameter. Instead, it first identifies the current load condition of the motor, distinguishes between normal operation and stalled operation, and then retrieves the corresponding normal operation overload allowable time or stalled overload allowable time from the preset dataset according to the corresponding operating condition, so as to realize differentiated overload protection thresholds under different operating conditions.

[0044] The operating condition can be determined based on the motor speed. When the speed is lower than the preset threshold, the operating condition is determined to be stalled; otherwise, it is determined to be in normal operating condition.

[0045] By differentiating overload allowable time according to operating conditions, the difference in heat tolerance between normal operation with air cooling and stalled operation without air cooling is fully considered, so that the protection threshold is more in line with the actual heat dissipation conditions of the motor. This avoids overheating damage during stalled operation and ensures that the protection is not triggered prematurely during normal operation, thus balancing safety and operational continuity.

[0046] It should be noted that, in addition to normal operation and stall, extended types such as braking condition and instantaneous heavy load condition can also be added, and an independent overload allowable time curve can be configured for each condition to further improve the protection adaptability and control accuracy under complex conditions.

[0047] In some implementations, the real-time current includes the actual current and the commanded current. Before performing thermal accumulation timing, the consistency between the actual current and the commanded current is determined. The corresponding thermal accumulation timing is performed only when the ratios of the actual current and the commanded current relative to the rated current simultaneously meet the timing conditions of the corresponding operating condition.

[0048] Actual current refers to the real operating current of the motor stator windings detected by the current sampling circuit and sensors. It is the current feedback value of the motor's actual operating state. Command current refers to the current command value calculated and output by the controller based on the motor control requirements and load conditions. It is the current reference value for driving the motor to operate as expected. The addition or subtraction of cumulative timing for heat accumulation is only executed when both the ratio of actual current to rated current and the ratio of command current to rated current simultaneously meet the overload or heat dissipation conditions.

[0049] In a specific example, if the current percentage is greater than or equal to a first threshold, it is defined as a motor overload condition; and if the current percentage is less than or equal to a second threshold, it is defined as a motor heat dissipation condition. Then: When the proportions of both the actual current and the commanded current exceed the first threshold, both simultaneously meet the overload condition, and the thermal accumulation accumulation timer is executed. When the proportions of both actual current and command current are less than the second threshold, both simultaneously meet the heat dissipation conditions, and the heat accumulation deduction cumulative timing is executed. When the proportion of actual current is greater than the first threshold and the proportion of command current is less than the second threshold, the two fail to meet the same operating condition at the same time. In this case, thermal accumulation is not performed, and the cumulative timing result remains unchanged.

[0050] By synchronously verifying the actual current and the command current in real time, the distortion of a single current signal caused by factors such as current sampling interference, abnormal sensor signals, and line transmission faults can be effectively filtered out, avoiding timing mis-triggering caused by a single abnormal current signal and improving the accuracy and reliability of thermal accumulation timing. Furthermore, the dual-channel consistency judgment only requires a simple numerical ratio comparison, without adding complex operations such as floating-point operations or integral calculations, resulting in low computational load. This aligns with the lightweight design concept of this invention and allows for stable operation in low-cost MCUs / fixed-point DSPs.

[0051] It should be noted that a percentage deviation threshold can also be added to the consistency judgment of the dual-channel real-time current. When the difference between the percentage of the actual current and the command current relative to the rated current exceeds the preset deviation threshold, it is directly judged as a current signal fault and an alarm is issued. At the same time, the thermal accumulation timing result is locked until the fault is cleared before normal dual-channel judgment and timing operation is restored, which further improves the fault identification capability and operational safety.

[0052] To clearly illustrate the method in this embodiment, a complete and continuous actual working condition is used for overall explanation: In this specific working condition, a servo motor with a certain rated current value is taken as the object, and the parameters are set as follows: the control cycle is a preset duration, the first threshold (overload accumulation threshold) is set to the first percentage higher than the rated current, the second threshold is set to the second percentage lower than the rated current, and the discretization lookup step size is a preset fixed step size. Examples of core parameters in the preset dataset are as follows: a certain overload current percentage corresponds to the first duration of the normal operating overload allowable time, and the second duration of the stalled overload allowable time; a certain light load current percentage corresponds to the third duration / cycle of the heat dissipation deduction time; another light load current percentage corresponds to the fourth duration / cycle of the heat dissipation deduction time; and the extreme overload percentage corresponds to the fifth duration of the stalled overload allowable time. The initial thermal accumulation timing value of the motor is set to zero. The real-time current includes the actual current and the commanded current. Before executing the thermal accumulation timing, a dual-path current consistency judgment must be completed. The specific execution process of each control cycle is as follows: First control cycle: The actual current and the command current are calculated and their current ratios both reach the overload threshold. The dual-path consistency judgment is passed, and the motor is determined to be in normal operating condition. The thermal accumulation operation is executed, and the accumulation is performed by a fixed time unit (e.g., the length of one control cycle). The thermal accumulation time value is updated to a time unit. The table is consulted to find that the normal operating overload allowable time under this current ratio is the first duration. The protection threshold has not been reached, so the motor does not have any protection action. The current thermal accumulation time value is output.

[0053] 100th control cycle: After accumulating multiple control cycles, if the ratio of the actual current to the command current is still the overload value mentioned above, the consistency judgment is passed, the normal operating condition remains unchanged, and the fixed accumulation continues to be executed. The thermal accumulation time value is accumulated to the first value, but the first duration protection threshold is not reached. The motor does not take any protection action, and the current thermal accumulation time value is output.

[0054] 101st control cycle: Motor stalls, controller determines stall condition, the ratio of actual current to command current is still the above overload value, consistency judgment passes, fixed accumulation continues, thermal accumulation time value increases by one time unit, look up table to find that stall overload allowable time under this current ratio is the second duration (corresponding to multiple control cycles), current time value has not reached protection threshold, motor has no protection action, output current thermal accumulation time value.

[0055] 299th control cycle: After stalling, run for several control cycles. The accumulated thermal accumulation time value is updated to a value close to the second duration. The ratio of the actual current to the command current is still the overload value mentioned above. The consistency judgment is passed. The second duration protection threshold has not been reached. The motor does not have any protection action. Output the current thermal accumulation time value.

[0056] 300th control cycle: After stalling, continue running for one control cycle. The accumulated thermal accumulation time value is updated to reach the second duration. The ratio of the actual current to the command current is still the above overload value. The consistency judgment is passed. The stall overload protection threshold is reached. The controller immediately triggers the pre-protection prompt, outputs the current thermal accumulation time value and issues an overload warning signal.

[0057] 301st control cycle: The fault is resolved in time, the load is reduced, and the ratio of the actual current and the command current both drop to a certain light load ratio (below the second threshold). The consistency judgment is passed, and it is determined to be a heat dissipation condition. The heat accumulation deduction operation is executed. The heat dissipation deduction time corresponding to the light load ratio is found to be the third duration / cycle. The heat accumulation time value is reduced accordingly, and the current heat accumulation time value is output.

[0058] 451st control cycle: After multiple control cycles of heat dissipation operation, the ratio of the actual current to the command current is still the same as the light load ratio. The consistency judgment is passed, and heat dissipation deduction is continuously executed. The heat accumulation time value gradually decreases to zero. The motor completes heat dissipation and outputs a heat accumulation time value of zero.

[0059] 452nd control cycle: The load fluctuates slightly, and the ratio of the actual current to the commanded current falls into the hysteresis range (e.g., between the second threshold and the first threshold). The accumulation / subtraction threshold conditions are not met, so no timing operation is performed, the thermal accumulation timing value remains at zero, the motor has no protection action, and the output thermal accumulation timing value is zero.

[0060] 453rd control cycle: The line has a brief abnormality. The ratio of the actual current and the command current is in the heat dissipation range and the overload range, respectively. The dual-path consistency judgment fails. No timing operation is performed. The thermal accumulation timing value remains at zero. The motor has no protection action. The output thermal accumulation timing value is zero.

[0061] 454th control cycle: The line abnormality is cleared. The ratio of the actual current and the command current is equal to the second threshold. The consistency judgment is passed. It is determined to be a heat dissipation condition. The heat accumulation deduction operation is executed. The heat dissipation deduction time corresponding to the current ratio is the fourth duration / cycle. The heat accumulation time value is kept at zero (without underflow). The heat accumulation time value is output as zero.

[0062] Control cycle 455: The motor suddenly experiences extreme load and stalls. The controller determines it to be a stall condition. The ratio of the actual current to the commanded current reaches the extreme overload value. The consistency judgment is passed, and the thermal accumulation operation is performed. The thermal accumulation time value is updated to one time unit. The table is looked up to find that the stall overload allowable time corresponding to the extreme overload ratio is the fifth duration (corresponding to a few control cycles). The protection threshold is not reached, so the motor does not have any protection action. The current thermal accumulation time value is output.

[0063] 459th control cycle: After several control cycles of extreme overload stall operation, if the ratio of the actual current to the commanded current is still the extreme overload value, the consistency judgment is passed, and the accumulation continues. The thermal accumulation time value is updated to reach the fifth duration, reaching the stall overload allowable time protection threshold, and the motor overload protection is immediately triggered, cutting off the motor drive circuit and outputting the protection action signal.

[0064] During overall operation, it accurately distinguishes between normal operating overload, stalled overload, heat dissipation, dead zone operation, and abnormal current signal, and performs operations such as fixed accumulation of heat, lookup table based on operating condition, variable deduction based on proportion, and time holding respectively. At the same time, it filters abnormal signal interference through dual-channel current consistency judgment, and uses discretized lookup table to replace traditional integral calculation. It takes into account the full utilization of motor overload capacity, accurate protection under different operating conditions, and lightweight calculation requirements, and is compatible with low-cost MCU / fixed-point DSP, thus improving the stability and reliability of motor overload protection.

[0065] like Figure 3 As shown, the second embodiment of the present invention provides a motor overload protection device, which includes: The thermal accumulation timing module 210 is used to acquire the real-time current of the motor, determine the ratio of the current current to the rated current, and perform thermal accumulation timing based on the current current ratio. The parameter lookup module 220 is used to query the overload allowable time or heat dissipation deduction time of the current current percentage based on a preset dataset. The preset dataset includes the overload allowable time, overload allowable time and heat dissipation deduction time of different current percentages during normal operation, during stalled operation, and respectively. The overload protection trigger module 230 is used to compare the thermal accumulation time with the overload allowable time, and trigger the overload protection when the thermal accumulation time reaches the allowable overload time.

[0066] Each module in the aforementioned motor overload protection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0067] like Figure 4 As shown, a third embodiment of the present invention provides an electronic device 300, which includes an input unit 310, a memory 320, at least one processor 330, and an output unit 340. The memory 320 stores program instructions that can be executed on the processor 330. The processor 330 can execute the motor overload protection method based on the foregoing embodiments by calling the program instructions. This electronic device can be a mobile terminal device such as a mobile phone or a computer.

[0068] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0069] The fourth embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described method embodiments.

[0070] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one of relational and non-relational databases. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these. The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0071] Compared with existing technologies, the motor overload protection method, device, electronic equipment, and storage medium provided by this invention replace the traditional continuous I / O method by using a three-stage lookup table, discrete data storage, and parameter configuration based on operating conditions. 2T-integral calculation significantly reduces computational load, eliminating the need for floating-point operations and real-time integration. Overload protection determination is achieved solely through simple table lookups and numerical comparisons. It is compatible with resource-constrained embedded hardware such as low-cost MCUs and fixed-point DSPs, enabling stable real-time operation in high-speed control loops. Simultaneously, a preset dataset differentiates the overload allowable time for normal operation and stall conditions, closely aligning with the motor's heat dissipation characteristics under different operating conditions. This solves the problem of inaccurate protection for stall conditions using traditional single protection curves, fully utilizing the motor's short-term overload capability while ensuring motor safety, thus improving the performance of the servo drive system. Furthermore, by matching the current ratio with the corresponding heat dissipation deduction time, the thermal capacitance effect and heat dissipation process of the motor can be accurately simulated, avoiding the protection misjudgments caused by traditional protection methods that only consider overload and ignore heat dissipation. Combined with precise comparison of thermal accumulation timing and overload allowable time to trigger protection, refined and scenario-based overload protection of the motor is achieved, effectively preventing damage to motor windings and driver power devices due to overload and overheating, thus improving the safety, reliability, and engineering practicality of the servo motor drive system.

[0072] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method of motor overload protection, characterized by, include: Obtain the real-time motor current, determine the ratio of the current current to the rated current, and perform thermal accumulation timing based on the current current ratio; Based on a preset dataset, query the overload allowable time or heat dissipation deduction time of the current current percentage. The preset dataset includes the overload allowable time, overload allowable time and heat dissipation deduction time of different current percentages during normal operation, during stalled operation, and respectively. The thermal accumulation time is compared with the overload allowable time, and the overload protection is triggered when the thermal accumulation time reaches the allowable overload time.

2. The motor overload protection method as described in claim 1, characterized in that: The current percentage in the preset dataset is divided into multiple discrete intervals according to a fixed step size of the rated current. Each discrete interval corresponds to the overload allowable time or the heat dissipation deduction time.

3. A method of motor overload protection as recited in claim 1 wherein, The step of performing thermal accumulation timing based on the current current percentage includes: When the current current percentage is greater than or equal to the first threshold, the cumulative time is increased; When the current current percentage is less than or equal to the second threshold, the accumulated time is deducted. Wherein, the first threshold is greater than the rated current, and the second threshold is less than the rated current.

4. The motor overload protection method as described in claim 3, characterized in that... include: There is a hysteresis interval between the first threshold and the second threshold. When the current current percentage is between the first threshold and the second threshold, the cumulative time remains unchanged.

5. The motor overload protection method as described in claim 3, characterized in that: When the current current percentage is greater than or equal to the first threshold, it increases in fixed time units, and when it is less than or equal to the second threshold, it is deducted by a predetermined value related to the current current percentage, wherein the smaller the current current percentage is, the larger the predetermined value is deducted.

6. The motor overload protection method as described in claim 1, characterized in that: When querying the overload allowable time of the current current percentage, the overload allowable time for normal operation or stall overload is queried according to the current operating conditions.

7. The motor overload protection method as described in claim 1, characterized in that: The real-time current includes the actual current and the commanded current. Before executing the thermal accumulation timing, the consistency between the actual current and the commanded current is also judged. The corresponding thermal accumulation timing is executed only when the ratio of the actual current and the commanded current to the rated current simultaneously meets the timing conditions of the corresponding operating condition.

8. A motor overload protection device, characterized in that, include: The thermal accumulation timing module is used to acquire the real-time current of the motor, determine the ratio of the current current to the rated current, and execute thermal accumulation timing based on the current current ratio. The parameter lookup module is used to query the overload allowable time or heat dissipation deduction time of the current current percentage based on a preset dataset. The preset dataset includes the overload allowable time, overload allowable time and heat dissipation deduction time of different current percentages during normal operation, during stalled operation, and respectively. The overload protection trigger module is used to compare the thermal accumulation time with the overload allowable time, and trigger overload protection when the thermal accumulation time reaches the allowable overload time.

9. An electronic device, characterized in that, include: The input unit, the memory, at least one processor and the output unit, the memory stores program instructions executable on the processor, and the processor calling the program instructions can execute the motor overload protection method as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the motor overload protection method as claimed in any one of claims 1 to 7.

Images