Motor overload protection method, device and equipment and storage medium

Abstract

The invention discloses a motor overload protection method, a motor overload protection device, motor overload protection equipment and a storage medium. The method comprises the following steps: receiving a data mapping table of different overload multiples, different operation time and different phase currents of different motors in a preset temperature interval obtained through a bench test; obtaining a three-phase current effective value of the to-be-monitored motor, determining the maximum operation time of the to-be-monitored motor according to the three-phase current effective value and the data mapping table, and determining a counter according to the maximum operation time; when the current value of the counter is greater than a preset counter threshold value, generating a motor overload fault, and adjusting the power of the to-be-monitored motor according to the motor overload fault; according to the motor overload protection device, the overload capacity of the motor can be accurately detected, the capacity of the motor can be exerted to the greatest extent, the conditions that the motor is seriously overloaded and the motor is burnt are avoided, the detection precision of motor overload detection is improved, the stability and safety of the motor are improved, and the speed and efficiency of motor overload protection are improved.

Description

Technical Field

[0001] This invention relates to the field of motor safety technology, and in particular to a method, device, equipment and storage medium for motor overload protection. Background Art

[0002] New energy vehicles use electric motors as their power source, and their reliability directly affects the performance of the entire vehicle. Electric motors and control systems are complex and diverse, and there are many types of motor failures. Currently, in order to output more power at the same cost, the industry generally pushes the power of the motor and its controller to the limit. Since the motor will work at an overload power for a long time, and the corresponding temperature sensors cannot detect the highest temperature point of the motor and controller, there is a risk of overload burnout of the motor and electronic control.

[0003] The currently widely used overload detection methods are based on The detection method involves the following: current heating is proportional to the square of the current, and heat accumulation is proportional to time. Therefore, the degree of overload can be expressed as the product of the square of the current and time. The operating current I is monitored in real time by a current sensor, and the results are discretized and calculated. t can be decomposed into several very small time intervals. And integrate the value calculated for each very small time unit. The heat generated by the motor can be obtained. By setting a protection threshold, the protection action is triggered when the accumulated value exceeds the threshold.

[0004] However, in practical applications, different motors have different heat tolerance capabilities. When setting parameters, it is necessary to understand the characteristics of the motor and make corresponding compensation for the ambient temperature. It is difficult to accurately detect motor overload. In addition, the response to instantaneous large current is not fast enough. Summary of the Invention

[0005] The main objective of this invention is to provide a method, device, equipment, and storage medium for motor overload protection, aiming to solve the technical problems in the prior art where different motors have different heat tolerance capabilities, parameter settings require understanding of motor characteristics, the motor overload detection process is complex, detection efficiency is low, the detection accuracy for motor overload is low, the response to instantaneous large currents is not fast enough, and the motor is prone to severe overload, leading to motor burnout.

[0006] In a first aspect, the present invention provides a method for protecting a motor from overload, the method comprising the following steps: Receive a data mapping table of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench testing; Obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time; When the current value of the counter is greater than the preset counter threshold, a motor overload fault is generated, and the power of the motor to be monitored is adjusted according to the motor overload fault.

[0007] Optionally, the receiving of a data mapping table obtained through bench testing of different motors for different overload ratios, different operating times, and different phase currents within a preset temperature range includes: The system receives a data mapping table obtained by detecting different positions of different motors using a thermal imager during bench testing. The data includes different overload ratios, different operating times, and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors.

[0008] Optionally, the step of obtaining the effective value of the three-phase current of the motor to be monitored, determining the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determining the counter based on the maximum running time includes: Obtain the effective value of the three-phase current of the motor to be monitored, and determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current; The maximum running time corresponding to the current overload multiple is obtained according to the data mapping table, and the counter is determined according to the maximum running time.

[0009] Optionally, obtaining the effective value of the three-phase current of the motor under monitoring and determining the current overload multiple of the motor under monitoring based on the effective value of the three-phase current includes: The three-phase current of the motor to be monitored is collected by Hall sensors, and the three-phase current is transformed by CLARK and PARK to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula:

[0010] in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

[0011] Optionally, obtaining the maximum running time corresponding to the current overload multiple based on the data mapping table, and determining the counter based on the maximum running time, includes: Find the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration for which the motor can continue to run when it reaches the highest temperature in the preset temperature range from the running time, and take the maximum running time as the maximum running time; A counter is determined based on the maximum running time, and the count is incremented or decremented at preset time intervals.

[0012] Optionally, the step of generating a motor overload fault when the current value of the counter is greater than a preset counter threshold, and adjusting the power of the monitored motor according to the motor overload fault, includes: When the current phase current of the motor to be monitored is greater than the current rated current of the motor, the ratio of the duration of the current motor overload multiple to the maximum running time is calculated to obtain the auto-increment step size of the counter. When the current phase current of the motor to be monitored is less than the current rated current of the motor, the ratio of the preset temperature drop time to the duration of the current motor overload multiple is calculated to obtain the decrement step size of the counter. Obtain the preset target counter accumulation range, determine the preset counter threshold based on the increment step size, the decrement step size and the preset target counter accumulation range, and compare the current value of the counter with the preset counter threshold. When the current value is greater than the preset counter threshold, a motor overload fault is generated; Adjust the power of the motor to be monitored based on the motor overload fault.

[0013] Optionally, adjusting the power of the monitored motor based on the motor overload fault includes: When the motor overload fault occurs, determine whether the overload fault flag bit of the control system of the motor to be monitored is set; When the overload fault flag is in position, the power of the motor to be monitored is reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor to be monitored is restored according to the preset power reduction current rise time.

[0014] Secondly, to achieve the above objectives, the present invention also proposes a motor overload protection device, the motor overload protection device comprising: The data table acquisition module is used to receive data mapping tables of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench tests. The counter determination module is used to obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time. The power adjustment module is used to generate a motor overload fault when the current value of the counter is greater than a preset counter threshold, and adjust the power of the motor to be monitored according to the motor overload fault.

[0015] Thirdly, to achieve the above objectives, the present invention also proposes a motor overload protection device, the motor overload protection device comprising: a memory, a processor, and a motor overload protection program stored in the memory and executable on the processor, the motor overload protection program being configured to implement the steps of the motor overload protection method described above.

[0016] Fourthly, to achieve the above objectives, the present invention also proposes a storage medium storing a motor overload protection program, wherein the motor overload protection program, when executed by a processor, implements the steps of the motor overload protection method described above.

[0017] The motor overload protection method proposed in this invention receives a data mapping table obtained through bench testing of different motors within a preset temperature range, showing different overload multiples, different running times, and different phase currents. It then acquires the effective value of the three-phase current of the motor under test, determines the maximum running time of the motor based on the effective value of the three-phase current and the data mapping table, and determines a counter based on the maximum running time. When the current value of the counter exceeds a preset counter threshold, a motor overload fault is generated, and the power of the motor under test is adjusted according to the motor overload fault. This method can accurately detect the motor's overload capacity, maximize the motor's capacity, avoid severe motor overload leading to motor burnout, improve the detection accuracy of motor overload detection, enhance the stability and safety of the motor, and improve the speed and efficiency of motor overload protection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of the present invention; Figure 2 This is a flowchart illustrating the first embodiment of the motor overload protection method of the present invention; Figure 3 This is a flowchart illustrating the second embodiment of the motor overload protection method of the present invention; Figure 4 This is a flowchart illustrating the third embodiment of the motor overload protection method of the present invention; Figure 5This is a flowchart illustrating the fourth embodiment of the motor overload protection method of the present invention; Figure 6 This is a schematic diagram of the power reduction method in the motor overload protection method of the present invention; Figure 7 This is a functional block diagram of the first embodiment of the motor overload protection device of the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] The solution of this invention mainly involves: receiving a data mapping table of different motors with different overload multiples, different running times, and different phase currents within a preset temperature range, obtained through bench testing; acquiring the effective value of the three-phase current of the motor to be monitored; determining the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table; determining a counter based on the maximum running time; generating a motor overload fault when the current value of the counter is greater than a preset counter threshold; and adjusting the power of the motor to be monitored based on the motor overload fault. This method can accurately detect the overload capacity of the motor, maximize the motor's capacity, avoid severe motor overload leading to motor burnout, improve the detection accuracy of motor overload detection, enhance the stability and safety of the motor, and improve the speed and efficiency of motor overload protection. It solves the technical problems in the prior art where different motors have different heat tolerances, parameter settings require understanding of motor characteristics, the motor overload detection process is complex, the detection efficiency is low, the detection accuracy of motor overload is low, the response to instantaneous large currents is not fast enough, and severe motor overload leading to motor burnout is likely to occur.

[0022] Reference Figure 1 , Figure 1 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of the present invention.

[0023] like Figure 1As shown, the device may include: a processor 1001, such as a CPU; a communication bus 1002; a user interface 1003; a network interface 1004; and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be high-speed RAM or non-volatile memory, such as a disk drive. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0024] Those skilled in the art will understand that Figure 1 The device structure shown does not constitute a limitation on the device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0025] like Figure 1 As shown, the memory 1005, which serves as a storage medium, may include an operating device, a network communication module, a user interface module, and a motor overload protection program.

[0026] The device of the present invention calls the motor overload protection program stored in the memory 1005 through the processor 1001 and performs the following operations: Receive a data mapping table of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench testing; Obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time; When the current value of the counter is greater than the preset counter threshold, a motor overload fault is generated, and the power of the motor to be monitored is adjusted according to the motor overload fault.

[0027] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: The system receives a data mapping table obtained by detecting different positions of different motors using a thermal imager during bench testing. The data includes different overload ratios, different operating times, and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors.

[0028] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: Obtain the effective value of the three-phase current of the motor to be monitored, and determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current; The maximum running time corresponding to the current overload multiple is obtained according to the data mapping table, and the counter is determined according to the maximum running time.

[0029] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: The three-phase current of the motor to be monitored is collected by Hall sensors, and the three-phase current is transformed by CLARK and PARK to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula:

[0030] in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

[0031] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: Find the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration for which the motor can continue to run when it reaches the highest temperature in the preset temperature range from the running time, and take the maximum running time as the maximum running time; A counter is determined based on the maximum running time, and the count is incremented or decremented at preset time intervals.

[0032] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: When the current phase current of the motor to be monitored is greater than the current rated current of the motor, the ratio of the duration of the current motor overload multiple to the maximum running time is calculated to obtain the auto-increment step size of the counter. When the current phase current of the motor to be monitored is less than the current rated current of the motor, the ratio of the preset temperature drop time to the duration of the current motor overload multiple is calculated to obtain the decrement step size of the counter. Obtain the preset target counter accumulation range, determine the preset counter threshold based on the increment step size, the decrement step size and the preset target counter accumulation range, and compare the current value of the counter with the preset counter threshold. When the current value is greater than the preset counter threshold, a motor overload fault is generated; Adjust the power of the motor to be monitored based on the motor overload fault.

[0033] The device of the present invention, through processor 1001 calling the motor overload protection program stored in memory 1005, also performs the following operations: When the motor overload fault occurs, determine whether the overload fault flag bit of the control system of the motor to be monitored is set; When the overload fault flag is in position, the power of the motor to be monitored is reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor to be monitored is restored according to the preset power reduction current rise time.

[0034] This embodiment, through the above-described scheme, receives a data mapping table obtained from bench tests of different motors within a preset temperature range, showing different overload ratios, different running times, and different phase currents; obtains the effective value of the three-phase current of the motor to be monitored; determines the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table; determines a counter based on the maximum running time; generates a motor overload fault when the current value of the counter exceeds a preset counter threshold; and adjusts the power of the motor to be monitored based on the motor overload fault. This approach can accurately detect the motor's overload capacity, maximize the motor's capabilities, avoid severe motor overload leading to motor burnout, improve the detection accuracy of motor overload detection, enhance the stability and safety of the motor, and increase the speed and efficiency of motor overload protection.

[0035] Based on the above hardware structure, an embodiment of the motor overload protection method of the present invention is proposed.

[0036] Reference Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of the motor overload protection method of the present invention.

[0037] In the first embodiment, the motor overload protection method includes the following steps: Step S10: Receive the data mapping table of different motors with different overload multiples, different running times and different phase currents within the preset temperature range, obtained through bench testing.

[0038] It should be noted that bench testing can be used to test different models of motors, that is, to test different motors under different overload multiples, different phase currents and different operating times within a pre-set temperature range, forming a data mapping table of different overload multiples, different operating times and different phase currents.

[0039] Step S20: Obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time.

[0040] It should be understood that after obtaining the effective value of the three-phase current of the motor to be monitored, the maximum running time of the motor to be monitored, i.e. the maximum running time of the current within the preset temperature range, can be determined by the effective value of the three-phase current and the data mapping table. The counter can be determined based on the maximum running time.

[0041] Step S30: When the current value of the counter is greater than the preset counter threshold, a motor overload fault is generated, and the power of the motor to be monitored is adjusted according to the motor overload fault.

[0042] It is understandable that when the current value of the counter is greater than the preset counter threshold, it can be determined that the motor has been overloaded. At this time, a motor overload fault is generated, and then the power of the motor to be monitored is adjusted according to the motor overload fault to prevent the motor from overheating and ensure motor safety.

[0043] This embodiment, through the above-described scheme, receives a data mapping table obtained from bench tests of different motors within a preset temperature range, showing different overload ratios, different running times, and different phase currents; obtains the effective value of the three-phase current of the motor to be monitored; determines the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table; determines a counter based on the maximum running time; generates a motor overload fault when the current value of the counter exceeds a preset counter threshold; and adjusts the power of the motor to be monitored based on the motor overload fault. This approach can accurately detect the motor's overload capacity, maximize the motor's capabilities, avoid severe motor overload leading to motor burnout, improve the detection accuracy of motor overload detection, enhance the stability and safety of the motor, and increase the speed and efficiency of motor overload protection.

[0044] Furthermore, Figure 3 This is a flowchart illustrating the second embodiment of the motor overload protection method of the present invention, as shown below. Figure 3 As shown, based on the first embodiment, a second embodiment of the motor overload protection method of the present invention is proposed. In this embodiment, step S10 specifically includes the following steps: Step S11: Receive a data mapping table obtained by detecting different positions of different motors using a thermal imager during bench testing. The data includes different overload multiples, different running times, and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors.

[0045] It should be noted that during bench testing, thermal imagers can be used to detect different positions of different motors and obtain data mapping tables of different overload multiples, different running times and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors. After the data mapping table is generated, the relevant data can be received directly, and it is not necessary to conduct bench testing again each time.

[0046] In the specific implementation, taking a motor with a rated current of 300A as an example, to ensure that the controller still has a certain output capability under the premise of safety, the collected measured data are shown in the table below:

[0047] It should be noted that the table above can be obtained through bench testing, using thermal imagers or other testing instruments to inspect various positions of the motor.

[0048] In a specific implementation, when the ratio of phase current to motor rated current (overload multiple) is within a certain range at the operating temperature (e.g., 60°C), the motor running time is recorded. The motor temperature will continue to rise. When the highest temperature of the motor reaches the temperature threshold (e.g., 160°C), the running time is recorded, which is the maximum running time of the current in that range. Of course, other values ​​can also be set, and this embodiment does not limit this.

[0049] This embodiment, through the above-described scheme, obtains a data mapping table of different motors with different overload multiples, different running times, and different phase currents within a preset temperature range by receiving data from different positions of different motors detected by a thermal imager during bench testing. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors. This allows for rapid acquisition of the data mapping table, improving the detection accuracy of motor overload detection, enhancing the stability and safety of the motor, and increasing the speed and efficiency of motor overload protection.

[0050] Furthermore, Figure 4 This is a flowchart illustrating the third embodiment of the motor overload protection method of the present invention, as shown below. Figure 4 As shown, based on the first embodiment, a third embodiment of the motor overload protection method of the present invention is proposed. In this embodiment, step S20 specifically includes the following steps: Step S21: Obtain the effective value of the three-phase current of the motor to be monitored, and determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current.

[0051] It should be noted that after obtaining the effective value of the three-phase current of the motor to be monitored, the current overload multiple of the motor to be monitored can be determined based on the effective value of the three-phase current.

[0052] Furthermore, step S21 specifically includes the following steps: The three-phase current of the motor to be monitored is collected by Hall sensors, and the three-phase current is transformed by CLARK and PARK to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula:

[0053] in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

[0054] It is understandable that the motor collects three-phase current through Hall sensors. The three-phase current is transformed by CLARK and PARK to obtain two-phase currents Id and Iq in the rotating coordinate system. The effective value Is of the three-phase current can be obtained by taking the square of the sum of the squares of the two-phase currents, as shown in the formula above.

[0055] It should be noted that the Clark transform and the Park transform are two important coordinate transformation techniques used in the field of motor control for mathematical modeling and control of three-phase AC motors. Their core function is to convert complex three-phase AC quantities (voltage, current, flux linkage, etc.) into DC components that are easier to analyze and control, thereby simplifying the design of motor control algorithms.

[0056] It should be understood that when three-phase AC motors (such as asynchronous motors and synchronous motors) are energized with three-phase AC current, the resulting magnetic field is a rotating magnetic field. Its physical quantities such as voltage, current, and flux linkage are all sinusoidal quantities that change with time, and there is a phase difference (120°) between the three phases. Directly analyzing and controlling these AC quantities (such as speed regulation and torque control) would be very complex. Through Clark and Park transformations, the three-phase AC system can be converted into an equivalent DC system: AC quantities are converted into DC quantities, eliminating the coupling relationship between time and phase; the complex AC motor model is converted into a model similar to a DC motor, which facilitates the design of linear controllers.

[0057] Step S22: Obtain the maximum running time corresponding to the current overload multiple according to the data mapping table, and determine the counter according to the maximum running time.

[0058] It is understandable that the maximum running time can be obtained by looking up a table, that is, the maximum running time corresponding to the current overload multiple can be obtained according to the data mapping table, and then the counter can be determined according to the maximum running time.

[0059] It should be understood that the maximum running time refers to the longest time that a motor can run continuously under overload conditions (current exceeding the rated value) (generally determined by the motor's tolerance, load characteristics, etc.). For example, if a motor has a rated current of 10A and allows a short-term overload of 15A, but can only run for a maximum of 3 minutes (the windings will overheat and be damaged if it exceeds 3 minutes), then the "maximum running time" is 3 minutes.

[0060] Furthermore, step S22 specifically includes the following steps: Find the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration for which the motor can continue to run when it reaches the highest temperature in the preset temperature range from the running time, and take the maximum running time as the maximum running time; A counter is determined based on the maximum running time, and the count is incremented or decremented at preset time intervals.

[0061] It should be noted that the running time corresponding to the current overload multiple can be found in the data mapping table, and then the maximum duration of continuous operation of the motor when it reaches the highest temperature in the preset temperature range can be selected from the running time, and then the maximum running time can be used as the maximum running time; a counter that increments or decrements at preset time intervals can be determined based on the maximum running time.

[0062] It is understandable that the maximum running time is determined by presetting the limit of continuous operation of the motor under overload conditions, such as based on parameters such as the motor's heat resistance characteristics and insulation class. This embodiment does not impose any restrictions on this, and uses this duration as a benchmark to set the trigger threshold of the counter.

[0063] In the specific implementation, the overload factor, i.e., the ratio of Is to the rated current of the motor, is calculated, and the maximum running time t1(s) is obtained by looking up the overload factor in a table; the counter N is determined, and the counter is incremented or decremented every 10ms of program execution time; as shown in the following formula:

[0064] in, is the counter value, and n is the increment / decrement step size of the counter in each program execution cycle.

[0065] This embodiment, through the above-described scheme, obtains the effective value of the three-phase current of the motor to be monitored, determines the current overload multiple of the motor to be monitored based on the effective value of the three-phase current, obtains the maximum running time corresponding to the current overload multiple based on the data mapping table, and determines the counter based on the maximum running time. This enables rapid determination of the counter, improves the detection accuracy of motor overload detection, and enhances the speed and efficiency of motor overload protection.

[0066] Furthermore, Figure 5 This is a flowchart illustrating the fourth embodiment of the motor overload protection method of the present invention, as shown below. Figure 5 As shown, based on the first embodiment, a fourth embodiment of the motor overload protection method of the present invention is proposed. In this embodiment, step S30 specifically includes the following steps: Step S31: When the current phase current of the motor to be monitored is greater than the current rated current of the motor, calculate the ratio of the duration of the current motor overload multiple to the maximum running time, and obtain the auto-increment step size of the counter.

[0067] It should be noted that by comparing the current phase current of the motor under test with the current rated current of the motor, when the current phase current of the motor under test is greater than the current rated current of the motor, the ratio of the duration of the current motor overload multiple to the maximum running time can be calculated, thereby obtaining the auto-increment step size of the counter.

[0068] In practical implementation, taking a continuous operating time of 60 minutes under 1.1 times overload as an example, when the phase current is greater than the motor's rated current, the self-incrementing step size n can be calculated using the following formula with 60 minutes (3600s) as the base value: n=3600 / t1 Where t1 is the maximum running time obtained by looking up the overload factor in a table.

[0069] Step S32: When the current phase current of the motor to be monitored is less than the current rated current of the motor, calculate the ratio of the preset temperature drop time to the duration of the current motor overload multiple, and obtain the decrement step size of the counter.

[0070] It is understandable that by comparing the current phase current of the motor under test with the current rated current of the motor, when the current phase current of the motor under test is less than the current rated current of the motor, the ratio of the preset temperature drop time to the duration of the current motor overload multiple can be calculated, thereby obtaining the decrement step size of the counter.

[0071] In practical implementation, when the phase current is less than the rated current of the motor, the temperature drop time can be calculated using a time of 60 seconds (which can be calibrated to other values ​​according to actual conditions; this embodiment does not impose any restrictions on this) and the self-decreasing step size n can be calculated using the following formula: n = 3600 / 60 = 60 Step S33: Obtain the preset target counter accumulation range, determine the preset counter threshold based on the increment step size, the decrement step size and the preset target counter accumulation range, and compare the current value of the counter with the preset counter threshold.

[0072] It should be noted that the preset target counter accumulation range is a valid range or critical range allowed for the counter accumulation value, pre-set according to actual application requirements (e.g., control logic, protection thresholds, process monitoring targets, etc.). Step S34: When the current value is greater than the preset counter threshold, a motor overload fault is generated.

[0073] It is understandable that when the current value is greater than the preset counter threshold, a corresponding alarm message will be generated, that is, a motor overload fault will be generated.

[0074] In a practical implementation, taking an overload time of 60 minutes, a program execution time of 10 ms, and an increment step of 1 as an example, the counter threshold Nmax can be calculated using the following formula: Nmax = 60 * 60 * 1000 / 10 = 360000 When the value of counter N is greater than Nmax, a motor overload fault will be reported.

[0075] Step S35: Adjust the power of the motor to be monitored according to the motor overload fault.

[0076] It should be understood that the power of the motor under monitoring can be adjusted based on the motor overload fault.

[0077] Furthermore, step S35 specifically includes the following steps: When the motor overload fault occurs, determine whether the overload fault flag bit of the control system of the motor to be monitored is set; When the overload fault flag is in position, the power of the motor to be monitored is reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor to be monitored is restored according to the preset power reduction current rise time.

[0078] It should be noted that setting the overload fault flag means that when an overload condition is detected in the equipment (e.g., motor, circuit, etc.) (e.g., current exceeds the rated value, power exceeds the carrying capacity), the fault flag bit in the control system is set to an active state (usually represented by "1"), thereby recording the occurrence of the overload fault and providing a clear signal identifier for subsequent protection actions (such as shutdown, alarm) or fault diagnosis.

[0079] It should be understood that when the motor overload fault occurs, it can be determined whether the overload fault flag of the control system of the motor under test is set. When the overload fault flag is set, the power of the motor under test can be reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor under test can be restored according to the preset power reduction current rise time.

[0080] In the specific implementation, refer to Figure 6 , Figure 6 This is a schematic diagram of the power reduction method for motor overload protection in this invention, as shown below. Figure 6 As shown, after the overload fault flag is set, the power begins to decrease by 80% (this can be set to other values ​​depending on the actual situation, and this embodiment does not limit this). The power decrease current decrease time is 100ms (this can be set to other values ​​depending on the actual situation, and this embodiment does not limit this). The power decrease duration is 60s (this can be set to other values ​​depending on the actual situation, and this embodiment does not limit this). After 60s, the overload fault flag is cleared, the power begins to recover, and the power decrease current rise time is 1s (this can be set to other values ​​depending on the actual situation, and this embodiment does not limit this).

[0081] This embodiment, through the above-described scheme, calculates the ratio of the duration of the current motor overload multiple to the maximum running time when the current phase current of the monitored motor is greater than the current rated current of the motor, thus obtaining the increment step size of the counter; when the current phase current of the monitored motor is less than the current rated current of the motor, calculates the ratio of the preset temperature drop time to the duration of the current motor overload multiple, thus obtaining the decrement step size of the counter; obtains a preset target counter accumulation range, determines a preset counter threshold based on the increment step size, the decrement step size, and the preset target counter accumulation range, and compares the current value of the counter with the preset counter threshold; when the current value is greater than the preset counter threshold, a motor overload fault is generated; and adjusts the power of the monitored motor according to the motor overload fault. This allows for accurate detection of the motor's overload capacity, maximizing the motor's capabilities, avoiding severe motor overload and potential motor burnout, improving the detection accuracy of motor overload detection, enhancing motor stability and safety, and increasing the speed and efficiency of motor overload protection.

[0082] Accordingly, the present invention further provides a motor overload protection device.

[0083] Reference Figure 7 , Figure 7 This is a functional block diagram of the first embodiment of the motor overload protection device of the present invention.

[0084] In a first embodiment of the motor overload protection device of the present invention, the motor overload protection device includes: The data table acquisition module 10 is used to receive data mapping tables of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench tests.

[0085] The counter determination module 20 is used to obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time.

[0086] The power adjustment module 30 is used to generate a motor overload fault when the current value of the counter is greater than a preset counter threshold, and adjust the power of the motor to be monitored according to the motor overload fault.

[0087] The data table acquisition module 10 is also used to receive data mapping tables obtained by detecting different positions of different motors using a thermal imager during bench testing, showing different overload multiples, different running times and different phase currents of different motors within a preset temperature range. The preset temperature range is a range determined based on the operating temperature and maximum temperature of different motors.

[0088] The counter determination module 20 is further configured to obtain the effective value of the three-phase current of the motor to be monitored, determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current, obtain the maximum running time corresponding to the current overload multiple based on the data mapping table, and determine the counter based on the maximum running time.

[0089] The counter determination module 20 is also used to collect the three-phase current of the motor to be monitored through the Hall sensor, and to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system by performing CLARK transformation and PARK transformation on the three-phase current. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula:

[0090] in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

[0091] The counter determination module 20 is further configured to look up the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration of continuous operation of the motor when it reaches the highest temperature in the preset temperature range from the running time, and use the maximum duration as the maximum running time; and determine a counter that increments or decrements the count at preset time intervals based on the maximum running time.

[0092] The power adjustment module 30 is further configured to: calculate the ratio of the duration of the current motor overload multiple to the maximum running time when the current phase current of the motor under monitoring is greater than the current rated current of the motor, and obtain the increment step size of the counter; calculate the ratio of the preset temperature drop time to the duration of the current motor overload multiple when the current phase current of the motor under monitoring is less than the current rated current of the motor, and obtain the decrement step size of the counter; obtain a preset target counter accumulation range; determine a preset counter threshold based on the increment step size, the decrement step size, and the preset target counter accumulation range; compare the current value of the counter with the preset counter threshold; generate a motor overload fault when the current value is greater than the preset counter threshold; and adjust the power of the motor under monitoring according to the motor overload fault.

[0093] The power adjustment module 30 is further configured to determine whether the overload fault flag of the control system of the motor under test is set when the motor overload fault occurs; when the overload fault flag is set, reduce the power of the motor under test according to a preset power reduction percentage, a preset power current reduction time, and a preset power reduction duration; when the overload fault flag is cleared, restore the power of the motor under test according to a preset power reduction current rise time.

[0094] The steps for implementing each functional module of the motor overload protection device can be referred to in the various embodiments of the motor overload protection method of the present invention, and will not be repeated here.

[0095] Furthermore, this embodiment of the invention also proposes a storage medium storing a motor overload protection program, which, when executed by a processor, performs the following operations: Receive a data mapping table of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench testing; Obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time; When the current value of the counter is greater than the preset counter threshold, a motor overload fault is generated, and the power of the motor to be monitored is adjusted according to the motor overload fault.

[0096] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: The system receives a data mapping table obtained by detecting different positions of different motors using a thermal imager during bench testing. The data includes different overload ratios, different operating times, and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors.

[0097] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: Obtain the effective value of the three-phase current of the motor to be monitored, and determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current; The maximum running time corresponding to the current overload multiple is obtained according to the data mapping table, and the counter is determined according to the maximum running time.

[0098] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: The three-phase current of the motor to be monitored is collected by Hall sensors, and the three-phase current is transformed by CLARK and PARK to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula:

[0099] in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

[0100] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: Find the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration for which the motor can continue to run when it reaches the highest temperature in the preset temperature range from the running time, and take the maximum running time as the maximum running time; A counter is determined based on the maximum running time, and the count is incremented or decremented at preset time intervals.

[0101] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: When the current phase current of the motor to be monitored is greater than the current rated current of the motor, the ratio of the duration of the current motor overload multiple to the maximum running time is calculated to obtain the auto-increment step size of the counter. When the current phase current of the motor to be monitored is less than the current rated current of the motor, the ratio of the preset temperature drop time to the duration of the current motor overload multiple is calculated to obtain the decrement step size of the counter. Obtain the preset target counter accumulation range, determine the preset counter threshold based on the increment step size, the decrement step size and the preset target counter accumulation range, and compare the current value of the counter with the preset counter threshold. When the current value is greater than the preset counter threshold, a motor overload fault is generated; Adjust the power of the motor to be monitored based on the motor overload fault.

[0102] Furthermore, when the motor overload protection program is executed by the processor, it also performs the following operations: When the motor overload fault occurs, determine whether the overload fault flag bit of the control system of the motor to be monitored is set; When the overload fault flag is in position, the power of the motor to be monitored is reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor to be monitored is restored according to the preset power reduction current rise time.

[0103] Those skilled in the art will understand that all or part of the steps in the methods described above can be implemented by a program instructing related hardware. The program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium is a computer-readable storage medium, including: USB flash drive, mobile hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and other media that can store program code.

[0104] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0105] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0106] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for overload protection of a motor, characterized in that, The motor overload protection method includes: Receive a data mapping table of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench testing; Obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time; When the current value of the counter is greater than the preset counter threshold, a motor overload fault is generated, and the power of the motor to be monitored is adjusted according to the motor overload fault.

2. The motor overload protection method as described in claim 1, characterized in that, The receiving data mapping table, obtained through bench testing, shows different motors operating at different overload ratios, different running times, and different phase currents within a preset temperature range. This includes: The system receives a data mapping table obtained by detecting different positions of different motors using a thermal imager during bench testing. The data includes different overload ratios, different operating times, and different phase currents of different motors within a preset temperature range. The preset temperature range is determined based on the operating temperature and maximum temperature of different motors.

3. The motor overload protection method as described in claim 1, characterized in that, The steps of obtaining the effective value of the three-phase current of the motor under monitoring, determining the maximum running time of the motor under monitoring based on the effective value of the three-phase current and the data mapping table, and determining the counter based on the maximum running time include: Obtain the effective value of the three-phase current of the motor to be monitored, and determine the current overload multiple of the motor to be monitored based on the effective value of the three-phase current; The maximum running time corresponding to the current overload multiple is obtained according to the data mapping table, and the counter is determined according to the maximum running time.

4. The motor overload protection method as described in claim 3, characterized in that, The step of obtaining the effective value of the three-phase current of the motor under monitoring and determining the current overload multiple of the motor under monitoring based on the effective value of the three-phase current includes: The three-phase current of the motor to be monitored is collected by Hall sensors, and the three-phase current is transformed by CLARK and PARK to obtain the direct-axis current and quadrature-axis current in the rotating coordinate system. The effective values ​​of the three-phase currents are obtained from the direct-axis current and the quadrature-axis current using the following formula: in, This represents the effective value of the three-phase current. For direct-axis current, It is the quadrature-axis current; Obtain the rated current of the motor to be monitored, and use the ratio of the effective value of the three-phase current to the rated current as the current overload factor of the motor to be monitored.

5. The motor overload protection method as described in claim 3, characterized in that, The step of obtaining the maximum running time corresponding to the current overload multiple according to the data mapping table, and determining the counter according to the maximum running time, includes: Find the running time corresponding to the current overload multiple in the data mapping table, select the maximum duration for which the motor can continue to run when it reaches the highest temperature in the preset temperature range from the running time, and take the maximum running time as the maximum running time; A counter is determined based on the maximum running time, and the count is incremented or decremented at preset time intervals.

6. The motor overload protection method as described in claim 1, characterized in that, When the current value of the counter is greater than a preset counter threshold, a motor overload fault is generated, and the power of the monitored motor is adjusted according to the motor overload fault, including: When the current phase current of the motor to be monitored is greater than the current rated current of the motor, the ratio of the duration of the current motor overload multiple to the maximum running time is calculated to obtain the auto-increment step size of the counter. When the current phase current of the motor to be monitored is less than the current rated current of the motor, the ratio of the preset temperature drop time to the duration of the current motor overload multiple is calculated to obtain the decrement step size of the counter. Obtain the preset target counter accumulation range, determine the preset counter threshold based on the increment step size, the decrement step size and the preset target counter accumulation range, and compare the current value of the counter with the preset counter threshold. When the current value is greater than the preset counter threshold, a motor overload fault is generated; Adjust the power of the motor to be monitored based on the motor overload fault.

7. The motor overload protection method as described in claim 6, characterized in that, The step of adjusting the power of the motor under monitoring according to the motor overload fault includes: When the motor overload fault occurs, determine whether the overload fault flag bit of the control system of the motor to be monitored is set; When the overload fault flag is in position, the power of the motor to be monitored is reduced according to the preset power reduction percentage, the preset power current reduction time, and the preset power reduction duration. When the overload fault flag is cleared, the power of the motor to be monitored is restored according to the preset power reduction current rise time.

8. A motor overload protection device, characterized in that, The motor overload protection device includes: The data table acquisition module is used to receive data mapping tables of different motors with different overload multiples, different running times and different phase currents within a preset temperature range, obtained through bench tests. The counter determination module is used to obtain the effective value of the three-phase current of the motor to be monitored, determine the maximum running time of the motor to be monitored based on the effective value of the three-phase current and the data mapping table, and determine the counter based on the maximum running time. The power adjustment module is used to generate a motor overload fault when the current value of the counter is greater than a preset counter threshold, and adjust the power of the motor to be monitored according to the motor overload fault.

9. A motor overload protection device, characterized in that, The motor overload protection device includes: a memory, a processor, and a motor overload protection program stored in the memory and executable on the processor, the motor overload protection program being configured to implement the steps of the motor overload protection method as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium stores a motor overload protection program, which, when executed by a processor, implements the steps of the motor overload protection method as described in any one of claims 1 to 7.

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