Motor stall protection control method and device, electronic equipment and storage medium

Abstract

Embodiments of the application disclose a motor stall protection control method and device, electronic equipment and a storage medium. The method comprises: obtaining an estimated back electromotive force value and an estimated rotating speed value of a motor; if the estimated back electromotive force value and the estimated rotating speed value of the motor are both zero, controlling ramp constant current soft start of the motor in a motor self-oscillation and step current increment manner; and if the estimated back electromotive force value of the motor is less than a back electromotive force threshold value and the estimated rotating speed value of the motor is less than a first rotating speed threshold value or greater than a second rotating speed threshold value, controlling ramp constant current soft start of the motor in a motor forward and reverse rotation and step current increment manner. Through the application, the technical problem that the reliability and effectiveness of motor stall detection are low and effective barrier treatment cannot be performed for specific stall types in the related art is solved, and the technical effects that the reliability and effectiveness of motor stall detection are improved and effective barrier treatment can be performed for specific stall types are achieved.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a motor stall protection control method, device, electronic equipment and storage medium. Background Technology

[0002] During operation, circulating water pumps may become clogged with foreign objects due to water quality issues. When the pump motor becomes blocked, it can cause system malfunctions or even burn out the motor and drive board. Therefore, foreign object detection and clearance are essential safety protection functions for circulating water pumps.

[0003] In related technologies, the following solutions are commonly used: 1) Using position sensors such as Hall effect sensors or encoders to test the rotor position and determine the stall and stall handling procedures based on position changes. This method has disadvantages such as high cost, complex structure, demanding installation conditions, and high failure rate of position detection devices. 2) Using flow meter sensors to determine the occurrence of stall based on flow rate. However, this method has poor real-time performance, requiring a long time from the occurrence of stall to the determination result. During this determination time, it is easy to cause overheating of the stator windings and overcurrent of the drive MOSFET. In addition, motor stall and pipeline blockage can both cause abnormal flow, thus leading to misjudgment. 3) Special handling for locked rotor: By detecting the bus current and phase current, the occurrence of locked rotor is indirectly judged based on the abnormality of the bus current and phase current when the motor is locked. However, the locked rotor judgment is inaccurate. The bus overcurrent or phase current abnormality may be caused by abnormal voltage, damaged control board components, overpower, etc., and the cause logic is not unique. In addition, the real-time performance of locked rotor judgment is poor. When locked rotor occurs, there is a probability that the fault of bus overcurrent or phase current abnormality may not occur, thus incorrectly entering the start protection.

[0004] Therefore, the reliability and effectiveness of motor stall detection in related technologies are low, and they cannot effectively address specific stall types.

[0005] No effective solution has yet been proposed to address the above problems. Summary of the Invention

[0006] This application provides a motor stall protection control method, device, electronic device, and storage medium to at least solve the technical problem in the related art that the reliability and effectiveness of motor stall detection are low and that it is impossible to effectively handle specific stall types.

[0007] According to one aspect of the embodiments of this application, a motor stall protection control method is provided, comprising: when the motor is in a ramp constant current soft start, acquiring the back electromotive force (EMF) estimate and the speed estimate of the motor; if both the back EMF estimate and the speed estimate of the motor are zero, then controlling the ramp constant current soft start of the motor using motor self-oscillation and stepped current increment; if the back EMF estimate of the motor is less than a back EMF threshold and the speed estimate of the motor is less than a first speed threshold or greater than a second speed threshold, then controlling the ramp constant current soft start of the motor using motor forward and reverse rotation and stepped current increment; wherein, the first speed threshold is the lowest speed value when the motor is in a constant speed running state, the second speed threshold is the highest speed value when the motor is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value when the motor is in a constant speed running state.

[0008] Optionally, the motor self-oscillation method includes: sequentially changing the energizing sequence of the motor windings according to the first composite magnetic field direction to the second composite magnetic field direction, the second composite magnetic field direction to the third composite magnetic field direction, the third composite magnetic field direction to the fourth composite magnetic field direction, the fourth composite magnetic field direction to the fifth composite magnetic field direction, the fifth composite magnetic field direction to the sixth composite magnetic field direction, and the sixth composite magnetic field direction to the first composite magnetic field direction to make the motor self-oscillate; wherein, the angle of change of the second composite magnetic field direction, the third composite magnetic field direction, the fourth composite magnetic field direction, the fifth composite magnetic field direction, and the sixth composite magnetic field direction relative to the first composite magnetic field direction gradually increases, the angle of change between the first composite magnetic field direction and the second composite magnetic field direction is 60°, the angle of change between the second composite magnetic field direction and the third composite magnetic field direction is 60°, the angle of change between the third composite magnetic field direction and the fourth composite magnetic field direction is 60°, the angle of change between the fourth composite magnetic field direction and the fifth composite magnetic field direction is 60°, the angle of change between the fifth composite magnetic field direction and the sixth composite magnetic field direction is 60°, and the angle of change between the sixth composite magnetic field direction and the first composite magnetic field direction is 60°.

[0009] Optionally, during the self-oscillation of the motor, the method further includes: detecting the current phase current of the motor winding; if the current phase current of the motor winding is greater than the phase current threshold, then during the next self-oscillation of the motor, the energizing sequence corresponding to the associated synthetic magnetic field direction is shielded.

[0010] Optionally, the method of reversing the motor includes: determining the energizing sequence of the motor windings by sequentially changing the direction of the first composite magnetic field to the direction of the second, third, fourth, fifth, and sixth composite magnetic fields, and so on, to make the motor reverse direction; wherein the angle of change of the second, third, fourth, fifth, and sixth composite magnetic fields relative to the first composite magnetic field direction gradually increases, the angle of change between the first and second composite magnetic field directions is 60°, the angle of change between the second and third composite magnetic field directions is 60°, the angle of change between the third and fourth composite magnetic field directions is 60°, the angle of change between the fourth and fifth composite magnetic field directions is 60°, the angle of change between the fifth and sixth composite magnetic field directions is 60°, and the angle of change between the sixth and first composite magnetic field directions is 60°.

[0011] Optionally, during the forward and reverse rotation of the motor, the method further includes: detecting the current phase current of the motor winding; if the current phase current of the motor winding is greater than the phase current threshold, then reducing the duty cycle of the energizing sequence during the next forward and reverse rotation of the motor.

[0012] Optionally, the stepped current increment method includes: Step 1, determining the current phase current of the motor winding, and controlling the motor to perform ramp constant current soft start according to the current phase current; Step 2, if the motor successfully performs ramp constant current soft start, then the motor is switched from ramp constant current soft start to uniform speed operation; Step 3, if the motor fails to perform ramp constant current soft start, then the number of times the motor starts is recorded, the sum of the current phase current and the phase current increment value is used as the updated current phase current, and if the number of times the motor starts is less than or equal to the starting threshold, the steps of Step 1 are continued; Step 4, if the number of times the motor starts is greater than the starting threshold, then it is determined that the motor has failed to perform ramp constant current soft start.

[0013] Optionally, obtaining the estimated back electromotive force (EMF) and estimated speed of the motor includes: obtaining the stator phase voltage and phase current of the motor; performing vector transformation and coordinate transformation on the stator phase voltage and phase current of the motor to obtain the back EMF of the motor; determining the estimated back EMF and stator flux linkage angle of the motor corresponding to the back EMF of the motor; calculating the rotor flux linkage angle of the motor based on the power angle between the rotor and stator and the stator flux linkage angle of the motor; and differentiating the rotor flux linkage angle of the motor to obtain the estimated speed of the motor.

[0014] According to another aspect of the embodiments of this application, a motor stall protection control device is also provided, comprising: an acquisition module, configured to acquire the estimated back electromotive force and the estimated speed of the motor when the motor is in a ramp constant current soft start; a first control module, configured to control the ramp constant current soft start of the motor by means of motor self-oscillation and step-by-step current increment if both the estimated back electromotive force and the estimated speed are zero; and a second control module, configured to control the ramp constant current soft start of the motor by means of motor forward and reverse rotation and step-by-step current increment if the estimated back electromotive force is less than a back electromotive force threshold and the estimated speed is less than a first speed threshold or greater than a second speed threshold; wherein, the first speed threshold is the lowest speed value when the motor is in a constant speed running state, the second speed threshold is the highest speed value when the motor is in a constant speed running state, and the back electromotive force threshold is the back electromotive force value associated with the lowest speed value when the motor is in a constant speed running state.

[0015] According to another aspect of the embodiments of this application, an electronic device is also provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the steps of the method described in any of the preceding claims.

[0016] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform the steps of any one of the methods described above.

[0017] In this embodiment, when the motor is in a ramp constant current soft start state, the estimated back EMF and estimated speed of the motor are obtained. If both the estimated back EMF and estimated speed are zero, the ramp constant current soft start of the motor is controlled by motor self-oscillation and step-by-step current increment. If the estimated back EMF is less than the back EMF threshold and the estimated speed is less than the first speed threshold or greater than the second speed threshold, the ramp constant current soft start of the motor is controlled by motor forward and reverse rotation and step-by-step current increment. The first speed threshold is the lowest speed value when the motor is in a constant speed running state, the second speed threshold is the highest speed value when the motor is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value when the motor is in a constant speed running state. In other words, this application embodiment obtains the back EMF and speed estimates of the motor during ramp constant current soft start; determines the motor's stall type based on the back EMF and speed estimates. If both the back EMF and speed estimates are zero, it is the first stall type of the motor, and the ramp constant current soft start is controlled by motor self-oscillation and step-by-step current increment. If the back EMF estimate is less than the back EMF threshold and the speed estimate is less than the first speed threshold or greater than the second speed threshold, it is the second stall type of the motor, and the ramp constant current soft start is controlled by motor forward and reverse rotation and step-by-step current increment. This solves the technical problem in related technologies where the reliability and effectiveness of motor stall detection are low, and it is impossible to effectively overcome specific stall types. It achieves the technical effect of improving the reliability and effectiveness of motor stall detection and effectively overcoming specific stall types. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0019] Figure 1 A flowchart of a motor stall protection control method provided in this application embodiment;

[0020] Figure 2 A flowchart for detecting motor stall type is provided in an embodiment of this application;

[0021] Figure 3 A flowchart for another type of motor stall detection provided in this application embodiment;

[0022] Figure 4 A schematic diagram of the direction of the first synthetic magnetic field provided in an embodiment of this application;

[0023] Figure 5A schematic diagram of the direction of the second synthetic magnetic field provided in an embodiment of this application;

[0024] Figure 6 A schematic diagram of the direction of the third synthetic magnetic field provided in an embodiment of this application;

[0025] Figure 7 A schematic diagram of the direction of the fourth synthetic magnetic field provided in the embodiments of this application;

[0026] Figure 8 A schematic diagram of the direction of the fifth composite magnetic field provided in the embodiments of this application;

[0027] Figure 9 A schematic diagram of the sixth synthetic magnetic field direction provided in the embodiments of this application;

[0028] Figure 10 This is a schematic diagram of a motor stall protection control device provided in an embodiment of this application. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to limit a specific order. The steps shown in the flowcharts of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0031] According to one aspect of the embodiments of this application, a motor stall protection control method is provided. Figure 1 A flowchart of a motor stall protection control method provided in this application embodiment is shown below. Figure 1 As shown, the method includes the following steps:

[0032] Step S102: When the motor is in a ramp constant current soft start, obtain the estimated value of the motor's back electromotive force and the estimated value of its speed.

[0033] The ramp constant current soft starter gradually increases the starting current during the initial stage of motor startup. Once the current of the current phase reaches a preset value, it remains constant until the operation is completed.

[0034] Step S104: If the estimated back EMF and the estimated speed of the motor are both zero, the ramp constant current soft start of the motor is controlled by the motor self-oscillation and the step current increment method.

[0035] Step S106: If the estimated value of the back EMF of the motor is less than the back EMF threshold and the estimated value of the motor speed is less than the first speed threshold or greater than the second speed threshold, then the motor is controlled by forward and reverse rotation and step-by-step current increment to control the ramp constant current soft start of the motor; wherein, the first speed threshold is the lowest speed value when the motor is in a constant speed running state, the second speed threshold is the highest speed value when the motor is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value when the motor is in a constant speed running state.

[0036] Through the above steps, the predicted back EMF and speed of the motor during ramp constant current soft start can be obtained. Based on these predictions, the motor's stall type can be determined. If both the predicted back EMF and speed are zero, it indicates the first stall type, in which case the motor's ramp constant current soft start is controlled using motor self-oscillation and stepped current increments. If the predicted back EMF is less than the back EMF threshold and the predicted speed is less than the first speed threshold or greater than the second speed threshold, it indicates the second stall type, in which case the motor's forward and reverse rotation and stepped current increments are used to control the ramp constant current soft start. This solves the technical problem of low reliability and effectiveness in motor stall detection in related technologies, which cannot effectively address specific stall types. It achieves the technical effect of improving the reliability and effectiveness of motor stall detection and effectively addressing specific stall types.

[0037] For scenarios with no speed and no back EMF (corresponding to zero estimated back EMF and speed for the aforementioned motor): The motor shaft or blades are blocked by fine deposits or scale, leaving no room for motor movement and causing a stall. In this scenario, the motor has a large starting torque, no back EMF during the climbing phase, and no speed, specifically manifested as no speed and no back EMF observed during constant current soft start on a slope. To increase the accuracy of the judgment, a detection window is set during constant current soft start on a slope. By calculating the mean and variance of the estimated back EMF and speed within the detection window, this situation is determined to have occurred. The specific implementation process is as follows... Figure 2 As shown.

[0038] For scenarios with abnormal speed and very low back EMF (corresponding to the motor's back EMF estimate being less than the back EMF threshold and the motor's speed estimate being less than the first speed threshold or greater than the second speed threshold): The motor shaft or blades are jammed by large foreign objects, leaving the motor with a small range of motion, causing a stall. In this scenario, the motor's starting torque changes abruptly, the motor has a small back EMF during the ramp-up phase, and the speed is abnormal. Specifically, during ramp-up constant current soft start, the observer's speed output is abnormal (greater than the maximum limited speed or less than the minimum stable operating speed), the effective value of the back EMF is small, and it does not follow a sinusoidal pattern. To increase the accuracy of the judgment, a detection window is set during ramp-up constant current soft start. By calculating the mean and variance of the back EMF estimate and speed estimate within the detection window period, the occurrence of this situation is determined. The specific implementation process is as follows: Figure 3 As shown.

[0039] It should be noted that the estimated rotational speed can be calculated from the estimated back electromotive force (EMF). Back EMF is the electromotive force generated against the tendency of a changing current. Back EMF is commonly found in electromagnetic coils, such as relay coils, solenoid valves, contactor coils, motors, and inductors.

[0040] In this embodiment, schematic diagrams of the first, second, third, fourth, fifth, and sixth composite magnetic field directions are shown below. Figures 4 to 9 As shown.

[0041] In one optional embodiment, the motor self-oscillation method includes: sequentially changing the energizing sequence of the motor windings according to the first synthetic magnetic field direction to the second synthetic magnetic field direction, the second synthetic magnetic field direction to the third synthetic magnetic field direction, the third synthetic magnetic field direction to the fourth synthetic magnetic field direction, the fourth synthetic magnetic field direction to the fifth synthetic magnetic field direction, the fifth synthetic magnetic field direction to the sixth synthetic magnetic field direction, and the sixth synthetic magnetic field direction to the first synthetic magnetic field direction to determine the motor self-oscillation; wherein, the angle of change of the second synthetic magnetic field direction, the third synthetic magnetic field direction, the fourth synthetic magnetic field direction, the fifth synthetic magnetic field direction, and the sixth synthetic magnetic field direction relative to the first synthetic magnetic field direction gradually increases, the angle of change between the first synthetic magnetic field direction and the second synthetic magnetic field direction is 60°, the angle of change between the second synthetic magnetic field direction and the third synthetic magnetic field direction is 60°, the angle of change between the third synthetic magnetic field direction and the fourth synthetic magnetic field direction is 60°, the angle of change between the fourth synthetic magnetic field direction and the fifth synthetic magnetic field direction is 60°, the angle of change between the fifth synthetic magnetic field direction and the sixth synthetic magnetic field direction is 60°, and the angle of change between the sixth synthetic magnetic field direction and the first synthetic magnetic field direction is 60°.

[0042] First, the motor self-oscillation operation is performed to change the direction of the first synthetic magnetic field to the direction of the second synthetic magnetic field. If the motor self-oscillation operation fails, the operation is then performed to change the direction of the second synthetic magnetic field to the direction of the third synthetic magnetic field. If the motor self-oscillation operation fails, the operation is then performed to change the direction of the third synthetic magnetic field to the direction of the fourth synthetic magnetic field. If the motor self-oscillation operation fails, the operation is then performed to change the direction of the fourth synthetic magnetic field to the direction of the fifth synthetic magnetic field. If the motor self-oscillation operation fails, the operation is then performed to change the direction of the fifth synthetic magnetic field to the direction of the sixth synthetic magnetic field. If the motor self-oscillation operation fails, the operation is then performed to change the direction of the sixth synthetic magnetic field back to the direction of the first synthetic magnetic field. If any of the above motor self-oscillation operations is successful, it indicates that the motor stall has been cleared, and no further motor self-oscillation operations are necessary.

[0043] Each combination of magnetic field direction changes corresponds to the energizing sequence of a set of motor windings. The energizing sequence of the motor windings can be flexibly adjusted according to the duty cycle, switching rate, and number of switching operations.

[0044] Optionally, to ensure high-frequency, low-amplitude motor self-oscillation, during motor self-oscillation, the energizing sequence of the motor windings is determined by sequentially changing the direction of the first composite magnetic field to the second composite magnetic field, the direction of the second composite magnetic field to the third composite magnetic field, the direction of the third composite magnetic field to the fourth composite magnetic field, the direction of the fourth composite magnetic field to the fifth composite magnetic field, the direction of the fifth composite magnetic field to the sixth composite magnetic field, and the direction of the sixth composite magnetic field to the first composite magnetic field. The energizing sequence of each group of motor windings is based on a 10% duty cycle, a switching rate of 16K, and 50 switching cycles, meaning that the energizing sequence of each group of motor windings lasts for 3.125ms.

[0045] In the embodiments of this application, motor stalling that occurs when both the predicted back EMF and the predicted speed of the motor are zero is solved by motor self-vibration.

[0046] In an optional embodiment, during the self-oscillation of the motor, the method further includes: detecting the current phase current of the motor winding; if the current phase current of the motor winding is greater than the phase current threshold, then during the next self-oscillation of the motor, shielding the energizing sequence corresponding to the associated synthetic magnetic field direction.

[0047] In the embodiments of this application, during the motor self-oscillation process, for each set of motor windings corresponding to the change in the direction of the combined magnetic field, the current phase current of the motor windings is detected in real time. When the current phase current is greater than the phase current threshold, the energizing sequence of the relevant motor windings is automatically shielded in the next motor self-oscillation. For example, if an overcurrent is triggered when the energizing sequence of the motor windings corresponding to the change from the second combined magnetic field direction to the third combined magnetic field direction, the energizing sequence of that motor winding will be automatically avoided in the next cycle.

[0048] In one optional embodiment, the motor's forward and reverse rotation includes: determining the energizing sequence of the motor windings by sequentially changing the direction of the first composite magnetic field to the direction of the second, third, fourth, fifth, and sixth composite magnetic fields, and so on, to cause the motor to rotate in both directions; wherein the angle of change of the second, third, fourth, fifth, and sixth composite magnetic fields relative to the first composite magnetic field direction gradually increases, the angle of change between the first and second composite magnetic field directions is 60°, the angle of change between the second and third composite magnetic field directions is 60°, the angle of change between the third and fourth composite magnetic field directions is 60°, the angle of change between the fourth and fifth composite magnetic field directions is 60°, the angle of change between the fifth and sixth composite magnetic field directions is 60°, and the angle of change between the sixth and first composite magnetic field directions is 60°.

[0049] The motor operates in both forward and reverse directions, with one electrical cycle as the operating cycle. This involves changing the direction of the first composite magnetic field to the second, then to the third, then to the fourth, then to the fifth, then to the sixth, then to the fifth, then to the fourth, then to the third, then to the second, and finally back to the first composite magnetic field. Each change follows the previous one, continuing until all changes are completed. Each timing sequence is repeated 10 times at a 10% duty cycle and a switching frequency of 16kHz. One electrical cycle represents the time it takes for a pair of magnetic poles to complete one revolution.

[0050] In the embodiments of this application, the motor stalling that occurs when the estimated value of the back EMF of the motor is less than the back EMF threshold and the estimated value of the motor speed is less than the first speed threshold or greater than the second speed threshold is solved by reversing the motor forward and reverse.

[0051] In an optional embodiment, during the forward and reverse rotation of the motor, the method further includes: detecting the current phase current of the motor winding; if the current phase current of the motor winding is greater than the phase current threshold, then reducing the duty cycle of the energizing timing during the next forward and reverse rotation of the motor.

[0052] The energizing sequence of the motor windings can be flexibly adjusted according to the duty cycle, switching speed, and number of switching operations. The duty cycle of the above energizing sequence can be flexibly adjusted according to the needs of the application scenario, for example, the duty cycle can be reduced by 1% or 2%.

[0053] In the embodiments of this application, during the forward and reverse rotation of the motor, the current phase current of the motor winding is detected in real time for one electrical cycle. When the current phase current is greater than the phase current threshold, the duty cycle of the next forward and reverse rotation is reduced by 1%. In addition, by reducing the duty cycle of the energizing sequence during the next forward and reverse rotation of the motor, the frequency of the forward and reverse rotation of the motor can be changed, thereby effectively solving the motor stall problem.

[0054] In one optional embodiment, the step-current increment method includes: Step 1, determining the current phase current of the motor winding, and controlling the motor to perform a ramp constant current soft start according to the current phase current; Step 2, if the motor successfully performs a ramp constant current soft start, then the motor is switched from ramp constant current soft start to uniform speed operation; Step 3, if the motor fails to perform a ramp constant current soft start, then the number of motor starts is recorded, the sum of the current phase current and the phase current increment value is used as the updated current phase current, and if the number of motor starts is less than or equal to the starting threshold, the steps of Step 1 are continued; Step 4, if the number of motor starts is greater than the starting threshold, then it is determined that the motor has failed to perform a ramp constant current soft start.

[0055] After the motor self-oscillates or reverses direction, a stepped current increment method is used to control the ramp constant current soft start of the motor. For example, the first step is: the motor self-oscillates or reverses direction; the second step is to execute a ramp constant current soft start with I1 as the current limit value. If the start is successful, it switches to normal closed-loop control (corresponding to switching the motor from ramp constant current soft start to uniform speed operation); otherwise, it proceeds to the next step, n = 0; the third step is to execute a ramp constant current soft start with I2 as the current limit value. If the start is successful, it switches to normal closed-loop control; otherwise, n++ and proceeds to the next step; the fourth step is to determine that the start failed if n > 5. It should be noted that I2 = I1 + n * δ I , n represents the number of times the motor is started, δ I This represents the incremental value of the phase current. When implementing a stepped current increment method, it is necessary to ensure that the current phase current is less than or equal to the current limit value.

[0056] In one optional embodiment, obtaining the predicted back electromotive force (EMF) and predicted rotational speed of the motor includes: obtaining the stator phase voltage and phase current of the motor; performing vector transformation and coordinate transformation on the stator phase voltage and phase current of the motor to obtain the back EMF of the motor; determining the predicted back EMF and stator flux linkage angle of the motor corresponding to the back EMF of the motor; calculating the rotor flux linkage angle of the motor based on the power angle between the rotor and stator and the stator flux linkage angle of the motor; and differentiating the rotor flux linkage angle of the motor to obtain the predicted rotational speed of the motor.

[0057] In the embodiments of this application, the back electromotive force (EMF) of the motor is calculated by directly obtaining the stator phase voltage and phase current of the motor. Then, the predicted back EMF and stator flux linkage angle of the motor corresponding to the back EMF are calculated. Furthermore, the rotor flux linkage angle of the motor is calculated using the power angle between the rotor and stator and the stator flux linkage angle. Finally, the predicted motor speed is obtained by differentiating the rotor flux linkage angle. In other words, the embodiments of this application can calculate the predicted back EMF and predicted motor speed more accurately with low cost and high reliability, without relying on sensors.

[0058] According to another aspect of the embodiments of this application, a motor stall protection control device is also provided. Figure 10 This is a schematic diagram of a motor stall protection control device provided in an embodiment of this application, as shown below. Figure 10 As shown, the motor stall protection control device includes: an acquisition module 1002, a first control module 1004, and a second control module 1006. The motor stall protection control device will be described in detail below.

[0059] The acquisition module 1002 is used to acquire the estimated back electromotive force and the estimated speed of the motor when the motor is in a ramp constant current soft start.

[0060] The first control module 1004 is connected to the acquisition module 1002 and is used to control the ramp constant current soft start of the motor by means of motor self-oscillation and step current increment if the back electromotive force prediction and speed prediction of the motor are both zero.

[0061] The second control module 1006, connected to the acquisition module 1002, is used to control the ramp constant current soft start of the motor by means of forward and reverse rotation of the motor and step-by-step current increment if the estimated value of the back EMF of the motor is less than the back EMF threshold and the estimated value of the motor speed is less than the first speed threshold or greater than the second speed threshold. The first speed threshold is the lowest speed value when the motor is in a constant speed running state, the second speed threshold is the highest speed value when the motor is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value when the motor is in a constant speed running state.

[0062] In the embodiments of this application, the motor stall protection control device can obtain the back EMF and speed estimates of the motor when it is in a ramp constant current soft start state. Based on the back EMF and speed estimates, the stall type of the motor is determined. If both the back EMF and speed estimates are zero, it is considered the first stall type, and the ramp constant current soft start is controlled using motor self-oscillation and stepped current increments. If the back EMF estimate is less than the back EMF threshold and the speed estimate is less than the first speed threshold or greater than the second speed threshold, it is considered the second stall type, and the ramp constant current soft start is controlled using motor forward / reverse rotation and stepped current increments. This solves the technical problem in related technologies where the reliability and effectiveness of motor stall detection are low, and it is impossible to effectively address specific stall types. This achieves the technical effect of improving the reliability and effectiveness of motor stall detection and effectively addressing specific stall types.

[0063] It should be noted that the above-mentioned acquisition module 1002, first control module 1004 and second control module 1006 correspond to steps S102 to S106 in the method embodiment. The examples and application scenarios implemented by the above modules and corresponding steps are the same, but are not limited to the content disclosed in the above method embodiment.

[0064] According to another aspect of the embodiments of this application, an electronic device is also provided, including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the steps of any of the methods described above.

[0065] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform the steps of any of the methods described above.

[0066] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0067] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of modules can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interface; the indirect coupling or communication connection of modules may be electrical or other forms.

[0068] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0069] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0070] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned computer-readable storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0071] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for controlling motor stall protection, characterized in that, include: When the motor is in a ramp constant current soft start, obtain the estimated back electromotive force and estimated speed of the motor; If the estimated back electromotive force and the estimated speed of the motor are both zero, then the ramp constant current soft start of the motor is controlled by the motor self-oscillation and the step current increment method. If the estimated back EMF of the motor is less than the back EMF threshold and the estimated speed of the motor is less than the first speed threshold or greater than the second speed threshold, then the ramp constant current soft start of the motor is controlled by rotating the motor in both forward and reverse directions and using a stepped current increment method; wherein, the first speed threshold is the lowest speed value of the motor when it is in a constant speed running state, the second speed threshold is the highest speed value of the motor when it is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value of the motor when it is in a constant speed running state.

2. The method according to claim 1, characterized in that, The self-oscillation methods of the motor include: The energizing sequence of the motor windings is determined by sequentially changing the direction of the first composite magnetic field to the second composite magnetic field, then to the third composite magnetic field, then to the fourth composite magnetic field, then to the fifth composite magnetic field, then to the sixth composite magnetic field, and finally back to the first composite magnetic field to ensure the motor's self-oscillation. The angles of change of the second, third, fourth, fifth, and sixth composite magnetic field directions relative to the first composite magnetic field direction gradually increase, with the angles between the first and second composite magnetic field directions being 60°, between the second and third composite magnetic field directions being 60°, between the third and fourth composite magnetic field directions being 60°, between the fourth and fifth composite magnetic field directions being 60°, between the fifth and sixth composite magnetic field directions being 60°, and between the sixth and first composite magnetic field directions being 60°.

3. The method according to claim 2, characterized in that, During the self-vibration process of the motor, the method further includes: Detect the current phase current of the motor winding; If the current phase current of the motor winding is greater than the phase current threshold, then the energizing sequence corresponding to the magnetic field direction of the shielding switch will be changed during the next self-oscillation of the motor.

4. The method according to claim 1, characterized in that, The forward and reverse rotation methods of the motor include: The energizing sequence of the motor windings is determined by sequentially changing the direction of the first composite magnetic field to the second, third, fourth, fifth, and sixth composite magnetic field directions, which in turn cause the motor to rotate in both directions. The angles of change of the second, third, fourth, fifth, and sixth composite magnetic field directions relative to the first composite magnetic field direction gradually increase. The angles of change between the first and second composite magnetic field directions are 60°, between the second and third composite magnetic field directions, between the third and fourth composite magnetic field directions, between the fourth and fifth composite magnetic field directions, between the fifth and sixth composite magnetic field directions, and between the sixth and first composite magnetic field directions are all 60°.

5. The method according to claim 4, characterized in that, During the forward and reverse rotation of the motor, the method further includes: Detect the current phase current of the motor winding; If the current phase current of the motor winding is greater than the phase current threshold, the duty cycle of the energizing sequence will be reduced during the next forward and reverse rotation of the motor.

6. The method according to claim 1, characterized in that, The stepped current increment method includes: Step 1: Determine the current phase current of the motor windings, and control the motor to perform ramp constant current soft start according to the current phase current; Step 2: If the motor successfully performs a ramp constant current soft start, then the motor is switched from a ramp constant current soft start to a constant speed running state. Step 3: If the motor fails to perform ramp constant current soft start, record the number of times the motor starts, use the sum of the current phase current and the phase current increment as the updated current phase current, and if the number of times the motor starts is less than or equal to the starting threshold, continue to execute the steps in step 1. Step 4: If the number of times the motor is started is greater than the starting threshold, then it is determined that the motor has failed to perform ramp constant current soft start.

7. The method according to any one of claims 1 to 6, characterized in that, Obtaining the estimated back electromotive force and estimated speed of the motor includes: Obtain the stator phase voltage and phase current of the motor; The back electromotive force of the motor is obtained by performing vector transformation and coordinate transformation on the stator phase voltage and phase current of the motor. Determine the estimated value of the back electromotive force of the motor and the stator flux linkage angle corresponding to the back electromotive force of the motor; The rotor flux linkage angle of the motor is calculated based on the power angle between the rotor and stator of the motor and the stator flux linkage angle of the motor. The estimated speed of the motor is obtained by differentiating the rotor flux linkage angle.

8. A motor stall protection control device, characterized in that, include: The acquisition module is used to acquire the estimated back electromotive force and estimated speed of the motor when the motor is in a ramp constant current soft start. The first control module is used to control the ramp constant current soft start of the motor by means of motor self-oscillation and step current increment if the back electromotive force and speed prediction of the motor are both zero. The second control module is used to control the ramp constant current soft start of the motor by means of forward and reverse rotation of the motor and step-by-step current increment if the estimated value of the back EMF of the motor is less than the back EMF threshold and the estimated value of the motor speed is less than the first speed threshold or greater than the second speed threshold; wherein, the first speed threshold is the lowest speed value of the motor when it is in a constant speed running state, the second speed threshold is the highest speed value of the motor when it is in a constant speed running state, and the back EMF threshold is the back EMF value associated with the lowest speed value of the motor when it is in a constant speed running state.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to perform the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the steps of the method according to any one of claims 1 to 7.

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