Brake control method, device and system of permanent magnet synchronous motor for sewing machine and sewing machine

Abstract

The invention provides a brake control method, device and system of a permanent magnet synchronous motor for a sewing machine and the sewing machine. The method comprises the steps that first motor state parameters measured by three Hall sensors and second motor state parameters estimated by a flux linkage observer are obtained; performing fine-grained reconstruction on the second motor state parameter by using the first motor state parameter to generate a third motor state parameter; after brake operation is triggered, the third motor state parameter serves as input, and a brake path of the motor is dynamically planned based on the three-loop control principle; and when the motor decelerates to be close to the target parking position according to the planned braking path, a lock shaft parking mechanism is triggered. By adopting the motor brake control mode of combining the flux linkage observer and the three Hall sensors, the stability of the brake performance is improved; through interpolation compensation, a more accurate machine angle, an electrical angle and a feedback speed are obtained, and reliable reference data are provided for dynamic planning of a brake path; and meanwhile, the consistency of parking time can be ensured, and the brake positioning precision is improved.

Description

Technical Field

[0001] This application belongs to the technical field of motor control, and relates to a braking control method, device and system for a permanent magnet synchronous motor used in a sewing machine, and a sewing machine. Background Art

[0002] During the operation of a sewing machine, a permanent magnet synchronous motor needs to frequently start and stop. The accuracy and stability of the braking control of the permanent magnet synchronous motor directly affect the operating efficiency and sewing quality of the sewing machine.

[0003] However, there are many technical bottlenecks in traditional braking control methods for permanent magnet synchronous motors, resulting in poor braking performance and difficulty in meeting the requirements of high-precision positioning.

[0004] On the one hand, traditional braking control methods usually rely on a single sensor to measure the angle or speed of the motor. However, the measurement method using a single sensor has obvious accuracy deficiencies in the low-speed operation stage of the motor. In the low-speed section, the speed of the motor changes relatively slowly, the signal strength is weak, and a single sensor is difficult to accurately capture and distinguish the subtle motion state of the motor, resulting in large errors in the measurement data. This lack of measurement accuracy is directly reflected in the braking performance, making the braking process less smooth and accurate, and affecting the overall operating effect of the sewing machine.

[0005] On the other hand, the actual working environment of a sewing machine is often relatively complex, often accompanied by harsh conditions such as high temperature, high pressure, and high electromagnetic interference. Under the action of these severe environmental factors, some sensors relied on by traditional braking control methods are extremely prone to failure. For example, a high-temperature environment may cause the performance of the electronic components inside the sensor to decline and the parameters to drift, affecting its normal operation; a high-pressure environment may damage the insulation performance of the sensor, causing problems such as short circuits or leakage; and high electromagnetic interference may interfere with the signal transmission and processing of the sensor, making it unable to accurately feedback the operating state of the motor. Once the sensor fails, it will trigger a failure of the entire braking control system, resulting in a sharp decline in braking performance, further seriously interfering with the normal operation of the sewing machine, and even possibly causing safety accidents. Summary of the Invention

[0006] The purpose of this application is to provide a braking control method, device and system for a permanent magnet synchronous motor used in a sewing machine, and a sewing machine, which are used to solve the technical problem of unstable braking performance existing in the prior art.

[0007] In the first aspect, this application provides a braking control method for a permanent magnet synchronous motor used in a sewing machine, including:

[0008] Obtain the first motor state parameters measured by three Hall sensors and the second motor state parameters estimated by a flux observer; the first motor state parameters include the measured value of the electrical angle, the measured value of the mechanical angle, and the measured value of the rotational speed; the second motor state parameters include the estimated value of the electrical angle, the estimated value of the mechanical angle, and the estimated value of the rotational speed;

[0009] Use the first motor state parameters to perform fine-grained reconstruction on the second motor state parameters to generate the third motor state parameters;

[0010] After the brake operation is triggered, use the third motor state parameters as the input and dynamically plan the brake path of the motor based on the three-loop control principle;

[0011] When the motor decelerates to near the target parking position according to the planned brake path, trigger the shaft locking parking mechanism.

[0012] In an implementation manner of the first aspect, using the first motor state parameters to perform fine-grained reconstruction on the second motor state parameters to generate the third motor state parameters includes:

[0013] Based on the interpolation algorithm, insert the estimated value of the electrical angle between adjacent sampling points of the measured value of the electrical angle to generate a reconstructed value of the electrical angle;

[0014] Based on the interpolation algorithm, insert the estimated value of the mechanical angle between adjacent sampling points of the measured value of the mechanical angle to generate a reconstructed value of the mechanical angle;

[0015] Based on the interpolation algorithm, insert the estimated value of the rotational speed between adjacent sampling points of the measured value of the rotational speed to generate a reconstructed value of the rotational speed;

[0016] Use the reconstructed value of the electrical angle, the reconstructed value of the mechanical angle, and the reconstructed value of the rotational speed as the third motor state parameters.

[0017] In an implementation manner of the first aspect, after the brake operation is triggered, using the third motor state parameters as the input and dynamically planning the brake path of the motor based on the three-loop control principle includes:

[0018] Obtain the brake operation trigger instruction;

[0019] In response to the brake operation trigger instruction, start the dual-loop control mode of the speed loop and the current loop to make the motor enter the rapid deceleration stage;

[0020] When it is detected that the motor speed drops to a preset speed value, switch from the dual-loop control mode to the three-loop control mode of the position loop, the speed loop, and the current loop to make the motor enter the planned deceleration stage;

[0021] Under the double-loop control mode and / or the triple-loop control mode, the current loop is adjusted by using the reconstructed electrical angle value to update the pulse width modulation signal for driving the motor; the speed loop is adjusted by using the reconstructed speed value to update the current loop command; and the position loop is adjusted by using the reconstructed mechanical angle value to update the speed loop command.

[0022] In an implementation manner of the first aspect, it further includes:

[0023] When the motor enters the planned deceleration stage, a planned braking position command is generated based on the mechanically measured angle value collected in real time, the target parking position, and the target braking time; the target parking position is set within a predetermined interval near the locked-rotor position;

[0024] Based on the planned braking position command, the motor is controlled to complete a specific number of braking turns within the target braking time, decelerate from the preset speed value to a complete stop, and finally reach the target parking position; where the specific number of braking turns is the number of complete mechanical angle cycles that the motor turns from the start of deceleration to a complete stop, and is related to the mechanically measured angle value.

[0025] In an implementation manner of the first aspect, it further includes:

[0026] Based on the speed measurement value collected in real time, it is judged whether the motor speed is close to zero;

[0027] If so, the d-axis current injection method of the current loop is used to enhance the input signal of the flux observer; where the input signal of the flux observer includes the stator voltage and current in the α-β axis coordinate system;

[0028] Otherwise, the motor speed is continuously monitored.

[0029] In an implementation manner of the first aspect, when the motor decelerates along the planned braking path to be close to the target parking position, triggering the locked-axis parking mechanism includes:

[0030] Recording the combined state of the three Hall signals when the last up / down needle stop Hall interruption is triggered;

[0031] Determining the target locked-axis angle according to the preset locked-axis parameters;

[0032] Based on the combined state of the three Hall signals, the motor rotor is forcibly positioned to the target locked-axis angle through an open-loop control algorithm.

[0033] In a second aspect, the present application provides a braking control device for a permanent magnet synchronous motor used in a sewing machine, including:

[0034] A parameter acquisition module, configured to acquire a first motor state parameter measured by a three Hall sensor and a second motor state parameter estimated by a flux observer; the first motor state parameter includes an electrical angle measurement value, a mechanical angle measurement value, and a rotational speed measurement value; the second motor state parameter includes an electrical angle estimation value, a mechanical angle estimation value, and a rotational speed estimation value;

[0035] A parameter reconstruction module, configured to perform fine-grained reconstruction on the second motor state parameter by using the first motor state parameter to generate a third motor state parameter;

[0036] A planned braking module, configured to, after a braking operation is triggered, use the third motor state parameter as an input and dynamically plan a braking path of the motor based on the three-loop control principle;

[0037] A shaft locking and parking module, configured to trigger a shaft locking and parking mechanism when the motor decelerates to a position close to a target parking position according to the planned braking path.

[0038] In a third aspect, the present application provides a braking control system for a permanent magnet synchronous motor used in a sewing machine, including:

[0039] A three Hall sensor, configured to measure a first motor state parameter;

[0040] A flux observer, configured to estimate a second motor state parameter;

[0041] The braking control device for a permanent magnet synchronous motor used in a sewing machine as described above, electrically connected to the three Hall sensor and the flux observer, and configured to execute the braking control method for a permanent magnet synchronous motor used in a sewing machine as described in any one of the above.

[0042] In an implementation manner of the third aspect, the flux observer is designed to continuously perform online estimation of the second motor state parameter during the entire operation cycle of the permanent magnet synchronous motor; the entire operation cycle of the permanent magnet synchronous motor includes a starting stage, a steady-state operation stage, and a braking stage.

[0043] In a fourth aspect, the present application provides a sewing machine, including: a sewing equipment body; the braking control system for a permanent magnet synchronous motor used in a sewing machine as described in any one of the above, and the system is electrically connected to the sewing equipment body.

[0044] As described above, the braking control method, device, system, and sewing machine for a permanent magnet synchronous motor used in the present application have the following beneficial effects:

[0045] (1) By adopting a motor braking control method combining a flux observer and a three Hall sensor, the stability of the braking performance is improved;

[0046] (2) Through interpolation compensation, more accurate mechanical angles, electrical angles, and feedback speeds are obtained, effectively suppressing the continuous growth of the cumulative error of the flux observer, solving the observation drift problem of the flux observer under low-speed conditions, and providing reliable reference data for the dynamic planning of the braking path;

[0047] (3) It can ensure the consistency of the parking time and improve the braking positioning accuracy. Description of the Drawings

[0048] Figure 1 It shows a schematic structural diagram of the braking control system of the permanent magnet synchronous motor for sewing machines according to the present application in an embodiment.

[0049] Figure 2 It shows a flowchart of the braking control method of the permanent magnet synchronous motor for sewing machines according to the present application in an embodiment.

[0050] Figure 3 It shows a flowchart of the braking control method of the permanent magnet synchronous motor for sewing machines according to the present application in another embodiment.

[0051] Figure 4 It shows a flowchart of the braking control method of the permanent magnet synchronous motor for sewing machines according to the present application in yet another embodiment.

[0052] Figure 5 It shows a working principle diagram of the three-loop control mode according to the present application in an embodiment.

[0053] Figure 6 It shows a flowchart of the braking control method of the permanent magnet synchronous motor for sewing machines according to the present application in still another embodiment.

[0054] Figure 7 It shows a schematic structural diagram of the braking control device of the permanent magnet synchronous motor for sewing machines according to the present application in an embodiment.

[0055] Figure 8 It shows a schematic structural diagram of the sewing machine according to the present application in an embodiment.

[0056] Figure 9 It shows a schematic structural diagram of the braking control system of the permanent magnet synchronous motor for sewing machines according to the present application in another embodiment. Detailed Embodiments

[0057] The following describes the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0058] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. Therefore, only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0059] In addition, in the present application, descriptions such as "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0060] The following embodiments of the present application provide a braking control method, device, system, and sewing machine for a permanent magnet synchronous motor of a sewing machine. By adopting a motor braking control method that combines a flux observer and three Hall sensors, the present application improves the stability of braking performance; through interpolation compensation, more accurate machine angles, electrical angles, and feedback speeds are obtained, effectively suppressing the continuous growth of the cumulative error of the flux observer and solving the observation drift problem of the flux observer under low-speed working conditions, providing reliable reference data for the dynamic planning of the braking path; at the same time, it can ensure the consistency of the parking time and improve the braking positioning accuracy.

[0061] Please refer to Figure 1 , which shows a schematic structural diagram of a braking control system for a permanent magnet synchronous motor of a sewing machine according to an embodiment of the present application.

[0062] As Figure 1 shown, this embodiment provides a braking control system for a permanent magnet synchronous motor of a sewing machine, including three Hall sensors, a flux observer, and a braking control device for a permanent magnet synchronous motor of a sewing machine.

[0063] In an embodiment of the present application, three Hall sensors are used to measure the first motor state parameters.

[0064] The three Hall sensors are sensors based on the Hall effect principle and have the ability to sense the rotor position simultaneously. The three Hall sensors in this embodiment are electrically connected to the motor and are used to measure the operating state parameters of the motor in real time.

[0065] Specifically, the first motor state parameters obtained by the three Hall sensors through measurement include electrical angle measurement values, mechanical angle measurement values, and rotational speed measurement values.

[0066] The electrical angle represents the spatial phase angle of the stator winding of the motor relative to the rotor magnetic flux, the mechanical angle represents the angle of rotation of the motor rotor around the axis in physical space, and the rotational speed represents the rotational rate of the motor rotor. For a multi-pole motor, the electrical angle is the mechanical angle multiplied by the number of pole pairs.

[0067] In an embodiment of the present application, a flux observer is used to estimate the second motor state parameters.

[0068] In the field of motor control, as a typical sensorless technology, the core function of the flux observer is to indirectly calculate state variables such as rotor position and speed by real-time collecting easily measurable electrical quantities such as current and voltage.

[0069] The flux observer in this embodiment is electrically connected to the braking control device of the permanent magnet synchronous motor for sewing machines, and estimates the second motor state parameters based on the input stator voltage and current in the α-β axis coordinate system.

[0070] Specifically, the second motor state parameters include electrical angle estimation values, mechanical angle estimation values, and rotational speed estimation values.

[0071] In other embodiments, the original output value of the flux observer is an angle increment, and the electrical angle and mechanical angle are obtained through the angle increment, where the angle increment represents the periodic difference of the electrical angle. For example, within a sampling period, the electrical angle changes from θ1 to θ2, then the angle increment Δθ can be expressed as: Δθ = θ2 - θ1. Combining with the number of pole pairs of the motor can realize the conversion between the electrical angle estimation value and the mechanical angle estimation value.

[0072] In an embodiment of the present application, the flux observer is designed to continuously perform online estimation of the second motor state parameters during the full operating cycle of the permanent magnet synchronous motor; the full operating cycle of the permanent magnet synchronous motor includes a starting stage, a steady-state operating stage, and a braking stage.

[0073] In this implementation method, by starting the iterative calculation of the flux observer throughout the entire operating cycle, the phenomenon of parameter mutation caused by the mismatch of the initial state of the flux observer or the failure to reach the steady state can be effectively avoided. This pre-intervention calculation mechanism enables the flux observer to continuously track the rotor angle and speed even when load mutation or operating condition switching occurs during the motor operation, thereby providing a reliable closed-loop control reference for the subsequent braking stage.

[0074] If the start of the flux observer is triggered only during the braking stage, since the motor may have experienced a long non-observation period at this time, there is a significant deviation between the initial state of the system and the actual operating condition, and it is extremely easy to generate a step jump in the angle estimation value. Through continuous calculation throughout the process, the flux observer can gradually converge to the true state, and the angle increment and speed estimation value output by it show continuous change characteristics in the time dimension, meeting the strict requirements of the braking control for the smoothness of state parameters. This design avoids the risk of transient mutation at the system level and ensures the controllability and safety of the motor under all operating conditions.

[0075] In an embodiment of the present application, the braking control device of the permanent magnet synchronous motor for sewing machines is electrically connected to the three Hall sensors and the flux observer, and is used to execute the braking control method of the permanent magnet synchronous motor for sewing machines described in the present application.

[0076] Next, the braking control device and method of the permanent magnet synchronous motor for sewing machines described in the embodiments of the present application will be described in detail with reference to the accompanying drawings in the embodiments of the present application.

[0077] Please refer to Figure 2 , which shows the flow chart of the braking control method of the permanent magnet synchronous motor for sewing machines described in the present application in an embodiment.

[0078] As Figure 2 shown, this embodiment provides a braking control method for a permanent magnet synchronous motor for sewing machines, including the following steps S100 to step S400.

[0079] In step S100, obtain the first motor state parameters measured by the three Hall sensors and the second motor state parameters estimated by the flux observer; the first motor state parameters include the measured value of the electrical angle, the measured value of the mechanical angle, and the measured value of the speed; the second motor state parameters include the estimated value of the electrical angle, the estimated value of the mechanical angle, and the estimated value of the speed.

[0080] It should be noted that the specific definitions, measurement methods, and physical meanings of the first motor state parameters and the second motor state parameters involved in this embodiment have been fully described in the related embodiments of the braking control system of the permanent magnet synchronous motor for sewing machines above, and will not be repeated here.

[0081] In step S200, the second motor state parameter is finely reconstructed using the first motor state parameter to generate a third motor state parameter.

[0082] Please refer to Figure 3 , which shows a flowchart of the braking control method for a permanent magnet synchronous motor used in a sewing machine according to the present application in another embodiment.

[0083] As Figure 3 shown, the fine-grained reconstruction of the second motor state parameter using the first motor state parameter to generate the third motor state parameter includes the following steps S201 to S204.

[0084] In step S201, the electrical angle estimated value is inserted between adjacent sampling points of the electrical angle measurement value based on an interpolation algorithm to generate an electrical angle reconstruction value.

[0085] In step S202, the mechanical angle estimated value is inserted between adjacent sampling points of the mechanical angle measurement value based on an interpolation algorithm to generate a mechanical angle reconstruction value.

[0086] In step S203, the rotational speed estimated value is inserted between adjacent sampling points of the rotational speed measurement value based on an interpolation algorithm to generate a rotational speed reconstruction value.

[0087] In step S204, the electrical angle reconstruction value, the mechanical angle reconstruction value, and the rotational speed reconstruction value are used as the third motor state parameter.

[0088] This embodiment realizes the correction of the estimated value of the flux observer using the absolute position measurement value of the Hall sensor, and realizes the complementary advantages of the two through the interpolation compensation algorithm, and finally generates high-precision and continuous motor state parameters. The specific principle is as follows:

[0089] The output characteristic of the Hall sensor is that it is triggered only at specific mechanical angles, such as 0°, 15°, 30°..., providing discrete absolute position measurement values, with high precision but sparse data. The limitation is that it cannot provide continuous angle information between two discrete points (such as 0° to 15°), resulting in limited real-time performance of the control system.

[0090] The output characteristic of the flux observer is that it continuously estimates parameters such as electrical angle and rotational speed based on the stator voltage and current in the input α-β axis coordinate system, with dense data but cumulative errors. During long-term operation, the estimated value may deviate from the true value due to noise, for example, the problem of increasing electrical angle error over time.

[0091] This application uses the absolute position measurement value of the Hall sensor as a high-precision "anchor point" to forcibly correct the estimated value of the flux observer at the corresponding moment. For example, if the estimated value of the observer at the 15° moment is 14.8°, it is forcibly aligned to 15° to eliminate the cumulative error. Between adjacent Hall measurement points (such as 0° to 15°), the continuous estimated values of the observer are filled into the missing intervals proportionally using interpolation algorithms (such as linear interpolation and spline interpolation). Specifically, the interpolation weight can be designed as follows: when approaching the Hall measurement point, the measured value is preferred (high weight); in the middle region, the estimated value of the observer is mainly used, but is constrained by the measured values at both ends. The finally output reconstructed values of the electrical angle, mechanical angle, and rotational speed not only retain the absolute accuracy of the Hall sensor but also possess the continuity of the flux observer.

[0092] In this implementation manner, by obtaining more accurate machine angles, electrical angles, and feedback speeds, the continuous growth of the cumulative error of the flux observer is effectively suppressed, the problem of observation drift existing in the flux observer under low-speed working conditions is solved, reliable reference data is provided for subsequent motion planning, the braking response speed and accuracy of the motor are improved, and the control performance of the whole machine is enhanced.

[0093] It is found in practical applications that this application can effectively reduce the hardware cost of the sensor while ensuring the observation accuracy by using low-cost three Hall sensors to replace traditional high-precision optical encoders. This technical route breaks through the traditional understanding that high-precision braking control must rely on expensive position sensors, and makes up for the inherent low-precision defects of Hall devices through a multi-source information fusion algorithm, and finally achieves a control effect equivalent to that of an optical encoder, with significant economic advantages.

[0094] In step S300, after the braking operation is triggered, using the third motor state parameter as the input, the braking path of the motor is dynamically planned based on the three-loop control principle.

[0095] Please refer to Figure 4 , which shows the flowchart of the braking control method for the permanent magnet synchronous motor used in the sewing machine according to this application in another embodiment.

[0096] As Figure 4 shown, after the braking operation is triggered, using the third motor state parameter as the input, dynamically planning the braking path of the motor based on the three-loop control principle includes the following steps S301 to S304.

[0097] In step S301, obtain the braking operation trigger instruction.

[0098] Specifically, an embedded pedal displacement sensor can be set to monitor the force of the operator stepping on the sewing machine brake pedal in real time. When it is detected that the travel of the brake pedal exceeds a preset threshold, a braking enable signal is triggered. After digital filtering and debouncing processing, this signal serves as the brake operation trigger instruction.

[0099] In step S302, in response to the brake operation trigger instruction, a dual-loop control mode of the speed loop and the current loop is started to make the motor enter the rapid deceleration stage.

[0100] Specifically, the control objective in the rapid deceleration stage is to reduce the rotational speed from high speed to medium speed in the shortest time. For example, a rapid deceleration process from 6000 rpm to 2000 rpm.

[0101] In step S303, when it is detected that the motor speed drops to a preset speed value, a three-loop control mode of the position loop, the speed loop, and the current loop is switched from the dual-loop control mode to make the motor enter the planned deceleration stage.

[0102] The planned deceleration stage described in this embodiment can achieve a smooth deceleration process from 2000 rpm to 0 rpm.

[0103] Due to the inertia of the motor, after the brake operation is triggered, the motor will not stop rotating immediately, but needs to continue rotating for several turns before gradually stopping. To achieve accurate stopping of the motor at the target position, the running path of the motor needs to be carefully planned.

[0104] Specifically, it is necessary to accurately calculate key parameters such as the number of turns the motor needs to rotate after the brake operation and the speed command values at different times. Through reasonable planning and precise control of these specific paths, the motor can run along a predetermined trajectory during the deceleration process and finally stop accurately at the target position.

[0105] In an embodiment of the present application, the brake control method for the permanent magnet synchronous motor used in the sewing machine described in this embodiment further includes:

[0106] When the motor enters the planned deceleration stage, based on the mechanically measured angle value, the target parking position, and the target braking time collected in real time, a planned braking position instruction is generated; the target parking position is set within a predetermined interval near the locked rotor position.

[0107] Based on the planned braking position instruction, after controlling the motor to complete a specific number of braking turns within the target braking time, it decelerates from the preset speed value to a complete stop and finally reaches the target parking position; where the specific number of braking turns is the number of complete mechanical angle cycles that the motor rotates from the start of deceleration to a complete stop, and is related to the mechanically measured angle value.

[0108] In actual operation, the target braking time and the target number of braking revolutions used from 2000 rpm to 0 rpm can be parsed from the planned braking position command. Based on the parsing results, stable control of the braking time and the number of braking revolutions can be achieved.

[0109] In this implementation mode, the position planning effect similar to that of an optical encoder, an inductive encoder or a magnetic encoder mode can be achieved, ensuring the consistency of each parking time and improving the braking accuracy.

[0110] In step S304, in the double-loop control mode and / or the triple-loop control mode, the current loop is adjusted by using the reconstructed electrical angle value to update the pulse width modulation signal for driving the motor; the speed loop is adjusted by using the reconstructed speed value to update the current loop command; the position loop is adjusted by using the reconstructed mechanical angle value to update the speed loop command.

[0111] Please refer to Figure 5 , which shows the working principle diagram of the triple-loop control mode described in this application in an embodiment.

[0112] In this implementation mode, through the dynamic switching strategy from double-loop control to triple-loop control and the triple-loop collaborative control process, segmented precise braking of the motor is achieved. It not only meets the real-time performance of high-speed braking but also achieves millimeter-level accuracy of the stop position.

[0113] In step S400, when the motor decelerates to approach the target stop position according to the planned braking path, the shaft locking parking mechanism is triggered.

[0114] In an embodiment of this application, when the motor decelerates to approach the target stop position according to the planned braking path, triggering the shaft locking parking mechanism includes the following steps S401 to S403.

[0115] In step S401, record the combined state of the three Hall signals when the last up and down stop needle Hall interrupt is triggered.

[0116] In step S402, determine the target shaft locking angle according to the preset shaft locking parameters.

[0117] In step S403, based on the combined state of the three Hall signals, the motor rotor is forcibly positioned to the target shaft locking angle through an open-loop control algorithm.

[0118] In this implementation mode, through the shaft locking mechanism, the motor rotor is forcibly positioned to the preset target shaft locking angle, ensuring the precise docking of the sewing machine at the target stop position. This greatly improves the accuracy and consistency of parking and reduces the error of the stop position.

[0119] Please refer to Figure 6, which shows the flowchart of the braking control method of the permanent magnet synchronous motor for sewing machines in yet another embodiment.

[0120] As Figure 6 shown, the braking control method of the permanent magnet synchronous motor for sewing machines described in this embodiment further includes the following steps S500 to S700.

[0121] Step S500: Based on the measured speed value collected in real time, determine whether the motor speed is close to zero;

[0122] Step S600: If the motor speed is close to zero, adopt the d-axis current injection method of the current loop to enhance the input signal of the flux observer; where the input signal of the flux observer includes the stator voltage and current in the α-β axis coordinate system;

[0123] Step S700: If the motor speed is not close to zero, continuously monitor the motor speed.

[0124] In the low-speed operation stage of the motor, since the current amplitude input to the flux observer is theoretically small, this will lead to a significant reduction in the reliability of the estimated value output by the flux observer. To address this technical problem, the present application proposes to adopt the d-axis current injection method of the current loop under low-speed working conditions, which can effectively increase the stator current amplitude in the low-speed state. When the current input to the flux observer reaches the preset threshold, the observation accuracy of the angle and speed can be significantly improved.

[0125] In this implementation manner, by implementing the d-axis current injection strategy in the low-speed range, the problem of insufficient reliability of the traditional observation method under this working condition is successfully solved. The experimental results show that this method can effectively improve the accuracy and dynamic stability of position estimation, especially showing good control performance in the working condition of frequent start and stop of sewing machines.

[0126] It should be noted that the protection scope of the braking control method of the permanent magnet synchronous motor for sewing machines described in the embodiments of the present application is not limited to the execution order of the steps listed in this embodiment. Any solution achieved by adding or subtracting steps of the prior art and replacing steps according to the principle of the present application is included in the protection scope of the present application.

[0127] Please refer to Figure 7 , which shows the structural schematic diagram of the braking control device of the permanent magnet synchronous motor for sewing machines described in the embodiments of the present application.

[0128] As Figure 7 shown, this embodiment provides a braking control device for a permanent magnet synchronous motor for sewing machines, including:

[0129] A parameter acquisition module, configured to acquire a first motor state parameter measured by three Hall sensors and a second motor state parameter estimated by a flux observer; the first motor state parameter includes an electrical angle measurement value, a mechanical angle measurement value, and a rotational speed measurement value; the second motor state parameter includes an electrical angle estimation value, a mechanical angle estimation value, and a rotational speed estimation value;

[0130] A parameter reconstruction module, configured to perform fine-grained reconstruction on the second motor state parameter by using the first motor state parameter to generate a third motor state parameter;

[0131] A planned braking module, configured to, after a braking operation is triggered, use the third motor state parameter as an input and dynamically plan a braking path of the motor based on the three-loop control principle;

[0132] A shaft locking parking module, configured to trigger a shaft locking parking mechanism when the motor decelerates to a position close to a target parking position according to the planned braking path.

[0133] It should be noted that the structures and principles of the parameter acquisition module, the parameter reconstruction module, the planned braking module, and the shaft locking parking module in this embodiment correspond one by one to the steps in the above-mentioned braking control method for a permanent magnet synchronous motor of a sewing machine, so details are not described herein again.

[0134] The braking control device for a permanent magnet synchronous motor of a sewing machine provided in an embodiment of the present application can implement the braking control method for a permanent magnet synchronous motor of a sewing machine described in the present application. However, the implementation device of the braking control method for a permanent magnet synchronous motor of a sewing machine described in the present application includes, but is not limited to, the structure of the braking control device for a permanent magnet synchronous motor of a sewing machine listed in this embodiment. Any structural deformation and replacement of the prior art made according to the principle of the present application are included in the protection scope of the present application.

[0135] Please refer to Figure 8 , which shows a structural schematic diagram of the sewing machine described in the present application in an embodiment.

[0136] As Figure 8 shown, this embodiment provides a sewing machine, including: a sewing equipment body; the braking control system for a permanent magnet synchronous motor of a sewing machine as described above, and the system is electrically connected to the sewing equipment body.

[0137] Please refer to Figure 9 , which shows a structural schematic diagram of the braking control system for a permanent magnet synchronous motor of a sewing machine described in the present application in another embodiment.

[0138] As Figure 9As shown, the braking control system of the permanent magnet synchronous motor for sewing machines provided in this embodiment includes a controlled module, a feedback module, a combination module of sensorless and Hall, and a control module. These modules work together to achieve stable braking of the motor.

[0139] Specifically, the controlled module includes a three-phase high-voltage driver and a servo motor. The three-phase high-voltage driver is electrically connected to the servo motor and is used to provide the required electrical energy for the servo motor.

[0140] The feedback module includes a current sampling unit and a three-Hall signal acquisition unit, which are used to monitor the operating state of the motor in real time. The current sampling unit is electrically connected to the three-phase high-voltage driver and is used to obtain the current signal Iab during motor operation. The three-Hall signal acquisition unit is electrically connected to the servo motor and is used to obtain the three-Hall signals.

[0141] The combination module of sensorless and Hall is used to receive the three-Hall signals collected by the three-Hall signal acquisition unit, as well as the stator voltage and current in the α-β axis coordinate system in the control module, and generate the electrical angle, mechanical angle, and electrical angle based on the sensorless flux observer and Hall combination algorithm.

[0142] The control module takes the electrical angle, mechanical angle, and rotational speed generated by the combination module of sensorless and Hall as inputs, and dynamically plans the braking path of the motor based on the three-loop control principle. The operation of the control module involves various advanced control algorithms and technologies such as inverse Park transformation, SVPWM (Space Vector Pulse Width Modulation), Clark transformation, and Park transformation. Through the coordinated action of these algorithms, the control module can accurately control the braking process of the motor to ensure the smoothness and rapidity of braking.

[0143] In several embodiments provided in this application, it should be understood that the disclosed system, device, or method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of modules / units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of devices or modules or units can be in electrical, mechanical, or other forms.

[0144] The modules / units described as separate components may or may not be physically separated, and the components shown as modules / units may or may not be physical modules, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules / units can be selected according to actual needs to achieve the objectives of the embodiments of the present application. For example, in various embodiments of the present application, each functional module / unit can be integrated into a processing module, or each module / unit can exist physically alone, or two or more modules / units can be integrated into one module / unit.

[0145] Those of ordinary skill in the art should further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0146] The descriptions of the processes or structures corresponding to the above-mentioned respective drawings each have their own focuses. For parts not detailed in a certain process or structure, reference can be made to the relevant descriptions of other processes or structures.

[0147] The above embodiments are only illustrative of the principles and effects of the present application and are not used to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those of ordinary skill in the art within the technical field without departing from the spirit and technical ideas disclosed in the present application should still be covered by the claims of the present application.

Claims

1. A braking control method for a permanent magnet synchronous motor used in a sewing machine, characterized in that, Including: Obtaining a first motor state parameter measured by a three Hall sensor and a second motor state parameter estimated by a flux observer; The first motor state parameter includes an electrical angle measurement value, a mechanical angle measurement value, and a rotational speed measurement value; the second motor state parameter includes an electrical angle estimated value, a mechanical angle estimated value, and a rotational speed estimated value; Using the first motor state parameter to perform fine-grained reconstruction on the second motor state parameter to generate a third motor state parameter; After a brake operation is triggered, using the third motor state parameter as an input, dynamically planning a brake path of the motor based on the three-loop control principle; When the motor decelerates to near the target parking position according to the planned brake path, triggering a shaft locking parking mechanism.

2. The method according to claim 1, wherein Using the first motor state parameter to perform fine-grained reconstruction on the second motor state parameter to generate a third motor state parameter includes: Inserting the electrical angle estimated value between adjacent sampling points of the electrical angle measurement value based on an interpolation algorithm to generate an electrical angle reconstruction value; Inserting the mechanical angle estimated value between adjacent sampling points of the mechanical angle measurement value based on an interpolation algorithm to generate a mechanical angle reconstruction value; Inserting the rotational speed estimated value between adjacent sampling points of the rotational speed measurement value based on an interpolation algorithm to generate a rotational speed reconstruction value; Taking the electrical angle reconstruction value, the mechanical angle reconstruction value, and the rotational speed reconstruction value as the third motor state parameter.

3. The method according to claim 2, wherein After a brake operation is triggered, using the third motor state parameter as an input, dynamically planning a brake path of the motor based on the three-loop control principle includes: Obtaining a brake operation trigger instruction; In response to the brake operation trigger instruction, starting a dual-loop control mode of a speed loop and a current loop to enable the motor to enter a rapid deceleration stage; When it is detected that the motor speed drops to a preset speed value, switching from the dual-loop control mode to a three-loop control mode of a position loop, a speed loop, and a current loop to enable the motor to enter a planned deceleration stage; In the dual-loop control mode and / or the three-loop control mode, adjusting the current loop using the electrical angle reconstruction value to update a pulse width modulation signal for driving the motor; adjusting the speed loop using the rotational speed reconstruction value to update a current loop command; adjusting the position loop using the mechanical angle reconstruction value to update a speed loop command.

4. The method according to claim 3, wherein Further including: When the motor enters the planned deceleration stage, generating a planned brake position command based on a real-time collected mechanical angle measurement value, a target parking position, and a target brake time; The target parking position is set within a predetermined interval near the locked rotor position; Based on the planned brake position command, controlling the motor to complete a specific number of brake turns within the target brake time, decelerating from the preset speed value to a complete stop, and finally reaching the target parking position; where the specific number of brake turns is the number of complete mechanical angle cycles that the motor rotates from the start of deceleration to a complete stop, and is related to the mechanical angle measurement value.

5. The method according to claim 1, characterized in that, Further including: Based on the real-time collected rotational speed measurement value, determining whether the motor speed is close to zero; If so, adopting a d-axis current injection method of the current loop to enhance an input signal of the flux observer; The input signals of the flux observer include the stator voltage and current in the α-β axis coordinate system; Otherwise, continuously monitor the motor speed.

6. The method according to claim 1, wherein When the motor decelerates to near the target stop position according to the planned braking path, the trigger for the shaft locking stop mechanism includes: Record the combined state of the three Hall signals at the last trigger of the upper and lower needle stop Hall interrupt; Determine the target shaft locking angle according to the preset shaft locking parameters; Based on the combined state of the three Hall signals, the motor rotor is forcibly positioned at the target shaft locking angle through an open-loop control algorithm.

7. A braking control device for a permanent magnet synchronous motor used in a sewing machine, characterized in that, Including: A parameter acquisition module for acquiring the first motor state parameters measured by a three-Hall sensor and the second motor state parameters estimated by a flux observer; the first motor state parameters include the measured value of the electrical angle, the measured value of the mechanical angle, and the measured value of the speed; the second motor state parameters include the estimated value of the electrical angle, the estimated value of the mechanical angle, and the estimated value of the speed; A parameter reconstruction module for performing fine-grained reconstruction of the second motor state parameters using the first motor state parameters to generate the third motor state parameters; A planned braking module for, after the braking operation is triggered, using the third motor state parameters as the input to dynamically plan the braking path of the motor based on the three-loop control principle; A shaft locking stop module for triggering the shaft locking stop mechanism when the motor decelerates to near the target stop position according to the planned braking path.

8. A braking control system for a permanent magnet synchronous motor used in a sewing machine, characterized in that, Including: A three-Hall sensor for measuring the first motor state parameters; A flux observer for estimating the second motor state parameters; The braking control device for a permanent magnet synchronous motor for a sewing machine as described in claim 7, electrically connected to the three-Hall sensor and the flux observer, for performing the braking control method for a permanent magnet synchronous motor for a sewing machine as described in any one of claims 1 to 6.

9. The system according to claim 8, wherein The flux observer is designed to continuously perform online estimation of the second motor state parameters during the entire operating cycle of the permanent magnet synchronous motor; the entire operating cycle of the permanent magnet synchronous motor includes a starting stage, a steady-state operating stage, and a braking stage.

10. A sewing machine, characterized in that, Including: A sewing equipment body; The braking control system for a permanent magnet synchronous motor for a sewing machine as described in any one of claims 8 to 9, the system being electrically connected to the sewing equipment body.

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