Sensorless motor control method and system, electronic product and storage medium

Abstract

The invention relates to the technical field of motor driving control, in particular to a sensorless motor control method and system, an electronic product and a storage medium. The method comprises the following steps: under the condition that the motor is in a non-static state, determining zero-crossing times of three-phase signals of the motor within a preset time length every preset time length; under the condition that the zero-crossing times are smaller than the zero-crossing times threshold value, back electromotive force detection is carried out on the motor, and the rotor position and the rotating speed of the motor are determined according to a back electromotive force detection result; and controlling the motor according to the rotor position and the rotating speed. By adopting the scheme, the motor control precision of the sensorless motor can be improved, and the stability of the sensorless motor during operation is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of motor drive control, and in particular to a sensorless motor control method, system, electronic product and storage medium. Background Art

[0002] Sensorless motors usually refer to motor control systems that do not rely on position sensors (such as Hall sensors) to determine the rotor position. Such systems are mostly used for brushless direct current motors (BLDC) or permanent magnet synchronous motors (PMSM).

[0003] When the sensorless motor enters the sensorless mode, it is necessary to change the current in the coil based on the rotor position to make the rotor rotate continuously. However, when the motor runs at low speed or zero speed, the stator voltage is very low; the existence of the dead zone will affect the accuracy of the stator voltage calculation, and the accuracy of the stator voltage will have a greater impact on the motor flux estimation, resulting in the sensorless motor often being difficult to obtain a good control effect when running at low speed; when outputting a large torque at low speed, it is often difficult to operate stably. Summary of the invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, a first objective of the present disclosure is to propose a sensorless motor control method to improve the motor control accuracy of the sensorless motor and enhance the stability of the sensorless motor during operation.

[0006] A second objective of the present disclosure is to provide a sensorless motor control system.

[0007] The third objective of the present disclosure is to provide an electronic product.

[0008] A fourth objective of the present disclosure is to provide a computer-readable storage medium.

[0009] A fifth object of the present disclosure is to provide a computer program product.

[0010] To achieve the above-mentioned purpose, a first aspect of the present disclosure provides a sensorless motor control method, comprising:

[0011] When the motor is in a non-stationary state, at every preset time length, determining the number of zero crossings of the three-phase signal of the motor within the preset time length;

[0012] When the number of zero crossings is less than a zero crossing number threshold, back electromotive force detection is performed on the motor, and a rotor position and a rotation speed of the motor are determined according to the back electromotive force detection result;

[0013] The motor is controlled according to the rotor position and the rotational speed.

[0014] Optionally, when the motor is in a non-stationary state, before determining the number of zero crossings of the three-phase signal of the motor within the preset time period at every preset time period, the method further includes:

[0015] Performing phase sequence and parameter identification on the motor, and detecting the current value of the motor when the identification result meets the phase sequence and parameter requirements;

[0016] If the current value is less than the current threshold, the rotor of the motor is reset to an initial position, and the motor is soft-started. During the soft-start process, the motor is commutated based on the identification result until the current value is not less than the current threshold, so that the motor is in a non-stationary state.

[0017] Optionally, the identifying the phase sequence and parameters of the motor includes:

[0018] Performing phase sequence identification on the motor to determine the A-phase winding, the B-phase winding, and the C-phase winding of the motor, wherein the A-phase winding leads the B-phase winding by 120 degrees, and the B-phase winding leads the C-phase winding by 120 degrees;

[0019] Providing a first power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor respectively in sequence, and performing voltage and current detection on the motor to obtain a first three-phase voltage, a first three-phase current and a first bus voltage;

[0020] Obtain a three-phase pulse width modulation waveform by calculating the motor speed, the digitized rotation angle signal and the current value through the first three-phase voltage, the first three-phase current and the first bus voltage based on a magnetic field oriented control strategy;

[0021] The motor is subjected to proportional-integral control according to the three-phase pulse width modulation waveform, and during the proportional-integral control, a first three-phase zero-crossing point and a first voltage absolute value maximum point of the motor are identified.

[0022] Optionally, performing a commutation operation on the motor based on the identification result during the soft start process includes:

[0023] Providing a second power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor in sequence, and performing voltage and current detection on the motor to obtain a second three-phase voltage, a second three-phase current and a second bus voltage;

[0024] Identify the second three-phase zero-crossing point and the second voltage absolute value maximum point corresponding to the second three-phase voltage, the second three-phase current and the second bus voltage;

[0025] Compare the second three-phase zero-crossing point with the first three-phase zero-crossing point, and compare the second voltage absolute value maximum point with the first voltage absolute value maximum point to obtain a comparison result;

[0026] A pulse width modulation phase sequence corresponding to the comparison result is determined, and a commutation operation is performed on the motor according to the pulse width modulation phase sequence.

[0027] Optionally, performing back electromotive force detection on the motor and determining the rotor position and speed of the motor according to the back electromotive force detection result includes:

[0028] Injecting a target signal into the stator winding of the motor, and determining a zero-crossing time interval of the three-phase signal of the motor after the target signal is injected, wherein the zero-crossing time interval is determined by the time interval between any two adjacent zero-crossing time points of the three-phase signal of the motor after the target signal is injected, wherein the frequency of the target signal is greater than a preset frequency;

[0029] The rotor position and the rotation speed of the motor are determined based on the time interval.

[0030] Optionally, after determining the number of zero crossings of the three-phase signal of the motor within the preset time length, the method further includes:

[0031] When the number of zero crossings is not less than the zero crossing threshold, determining the number of times the absolute value of the voltage of the motor reaches the highest point of the absolute value of the voltage within the preset time period;

[0032] The rotor position and the rotation speed of the motor are determined according to the zero-crossing times and the peak point times.

[0033] Optionally, controlling the motor according to the rotor position and the rotational speed includes:

[0034] Obtaining a third three-phase voltage and a third three-phase current of the motor;

[0035] Determine a current reference value, a speed reference value, and a rotor position reference value corresponding to a current loop of the motor;

[0036] The third three-phase current, the rotor position and the speed are used as inputs of the current loop, and the third three-phase voltage is used as feedback of the current loop, and the current loop is adaptively controlled so that the difference between the third three-phase current and the current reference value is less than a first difference threshold, the difference between the speed and the speed reference value is less than a second difference threshold, and the difference between the rotor position and the rotor position reference value is less than a third difference threshold.

[0037] To achieve the above-mentioned purpose, a second aspect of the present disclosure provides a sensorless motor control system, including:

[0038] A zero-crossing detection unit, used for determining the number of zero-crossings of the three-phase signal of the motor within a preset time period at intervals of a preset time period when the motor is in a non-stationary state;

[0039] a parameter determination unit, configured to perform back electromotive force detection on the motor when the number of zero crossings is less than a zero crossing number threshold, and determine a rotor position and a rotation speed of the motor according to the back electromotive force detection result;

[0040] A motor control unit is used to control the motor according to the rotor position and the rotation speed.

[0041] To achieve the above-mentioned purpose, a third aspect of the present disclosure provides an electronic product, including:

[0042] A memory for storing executable program codes;

[0043] A processor is used to call and run the executable program code from the memory, so that the electronic product executes the method shown in any one of the first aspects above.

[0044] To achieve the above-mentioned purpose, the fourth aspect of the present disclosure provides a computer-readable storage medium, which stores a computer program. When the computer program is executed, it implements the method shown in any one of the above-mentioned first aspects.

[0045] To achieve the above-mentioned objective, a fifth aspect of the present disclosure provides a computer program product, including a computer program, which, when executed by a processor, implements the method shown in any one of the above-mentioned first aspects.

[0046] In summary, the method, system, electronic product and storage medium provided by the present invention detect the zero-crossing point of the three-phase signal as a basis for the low-speed or zero-speed operation of the motor, and perform back-electromotive force detection on the motor when the motor is running at low speed or zero speed, and determine the rotor position and speed of the motor according to the back-electromotive force detection result, which can reduce the problem of poor control effect caused by low accuracy of stator voltage calculation, improve the motor control accuracy of the sensorless motor, and enhance the stability of the sensorless motor during operation.

[0047] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and / or additional aspects and advantages of the present disclosure will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0049] Figure 1 A schematic flow chart of a sensorless motor control method provided by an embodiment of the present disclosure;

[0050] Figure 2 A schematic diagram of the structure of a sensorless motor control system provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0052] The present disclosure is described in detail below with reference to specific embodiments.

[0053] In the first embodiment, if Figure 1 As shown, Figure 1 The present invention provides a flow chart of a sensorless motor control method provided by an embodiment of the present invention. The method can be implemented by a computer program and can be run on a system for performing sensorless motor control. The computer program can be integrated into an application or run as an independent tool application.

[0054] Among them, the sensorless motor control method can be executed by an electronic product.

[0055] For example, the sensorless motor control method includes the following steps:

[0056] S101, when the motor is in a non-stationary state, determining the number of zero crossings of the three-phase signal of the motor within a preset time period at intervals of a preset time period;

[0057] According to some embodiments, the non-stationary state refers to a state in which the shaft of the motor is continuously rotating. When the shaft of the motor is not rotating, the motor is in a stationary state.

[0058] In some embodiments, the preset duration does not specifically refer to a fixed duration, and the preset duration can be determined according to actual application scenarios. The preset duration can be, for example, 1 second.

[0059] According to some embodiments, the three-phase signal includes three-phase current and three-phase voltage, and recording the number of zero crossings of the three-phase signal of the motor may be recording the number of zero crossings of the three-phase current, or may be recording the number of zero crossings of the three-phase voltage of the motor.

[0060] In some embodiments, the zero-crossing count refers to the number of times a signal crosses zero within a certain period of time. For a periodic signal, the zero-crossing count can reflect the frequency of the signal. In the embodiment of the present disclosure, the zero-crossing count refers to the number of times the signal value of the three-phase signal is 0.

[0061] S102, when the number of zero crossings is less than the zero crossing number threshold, performing back electromotive force detection on the motor, and determining the rotor position and speed of the motor according to the back electromotive force detection result;

[0062] According to some embodiments, the zero-crossing number threshold is a set zero-crossing number value used to determine whether the motor is in a low-speed operation state. The zero-crossing number threshold can be determined according to the specific application and characteristics of the motor.

[0063] In some embodiments, if the number of zero crossings is less than the zero crossing threshold, it means that the motor speed is low and the motor can be considered to be in a low-speed running state; if the number of zero crossings is greater than the zero crossing threshold, it can be considered that the motor is in a normal or high-speed running state.

[0064] For example, when the zero-crossing threshold is 10 times / second, if the zero-crossing frequency detected is 5 times / second, and 5 times / second is less than 10 times / second, it means that the motor is in a low-speed running state; if the zero-crossing frequency detected is 15 times / second, and 15 times / second is greater than 10 times / second, it means that the motor is in a normal or high-speed running state.

[0065] According to some embodiments, when the motor is initially started, the field winding establishes a magnetic field, the armature current generates another magnetic field, and the two magnetic fields interact to start the motor running. The armature winding rotates in the magnetic field, thus generating a generator effect. In fact, the rotating armature generates an induced electromotive force, which is opposite to the polarity of the armature voltage. This self-induced electromotive force is called back electromotive force.

[0066] S103, controlling the motor according to the rotor position and speed.

[0067] In summary, the method provided in this embodiment detects the zero-crossing point of the three-phase signal as a basis for the motor to run at low speed or zero speed, and performs back-electromotive force detection on the motor when the motor runs at low speed or zero speed, and determines the rotor position and speed of the motor according to the back-electromotive force detection result. This can reduce the problem of poor control effect caused by low accuracy of stator voltage calculation, improve the motor control accuracy of the sensorless motor, and enhance the stability of the sensorless motor during operation.

[0068] This embodiment also provides another sensorless motor control method, which can be executed by an electronic product.

[0069] For example, the sensorless motor control method may include the following steps:

[0070] S201, performing phase sequence and parameter identification on the motor, and detecting the current value of the motor when the identification result meets the phase sequence and parameter requirements;

[0071] It should be noted that for a new motor, its phase sequence and parameters need to be identified before use. If the identification result does not meet the phase sequence and parameter requirements, it means that the motor phase sequence is abnormal and / or the parameters are abnormal, that is, it is in a fault state and the subsequent control process cannot be carried out; if the identification result meets the phase sequence and parameter requirements, it means that the motor phase sequence is normal and the parameters are normal, and the subsequent control process can be carried out.

[0072] According to some embodiments, when the phase sequence and parameter identification of the motor are performed, the phase sequence identification of the motor can be performed, and the A-phase winding, B-phase winding and C-phase winding of the motor can be determined; the first power supply voltage is provided to the A-phase winding, B-phase winding and C-phase winding of the motor respectively, and the voltage and current detection of the motor is performed to obtain the first three-phase voltage, the first three-phase current and the first bus voltage; the motor speed is calculated, the digital angle signal is calculated and the current value is calculated based on the field oriented control (Field Oriented Control, FOC) strategy through the first three-phase voltage, the first three-phase current and the first bus voltage, and the three-phase pulse width modulation waveform is obtained; the motor is proportionally integral (proportional integral, PI) controlled according to the three-phase pulse width modulation waveform, and in the process of proportional integral control, the first three-phase zero crossing point and the first voltage absolute value highest point of the motor are identified. Therefore, reliable data support can be provided for the control of the motor, the stability of the motor control can be improved, and by monitoring different data, the data is analyzed and compared, with more superior control quality and stronger interference suppression ability, which can effectively improve the robustness of weak magnetic control.

[0073] In some embodiments, the first power supply voltage refers to the power supply voltage used when performing phase sequence and parameter identification on the motor.

[0074] In some embodiments, the A-phase winding leads the B-phase winding by 120 degrees, and the B-phase winding leads the C-phase winding by 120 degrees. If the A-phase winding, the B-phase winding, and the C-phase winding that meet the above requirements are not identified during the phase sequence identification of the motor, it means that the phase sequence of the motor is abnormal, and the identification result does not meet the phase sequence and parameter requirements.

[0075] In some embodiments, the first three-phase zero-crossing point and the first voltage absolute value maximum point are used as a commutation basis for performing commutation operations when the motor is subsequently controlled.

[0076] S202, if the current value is less than the current threshold, the rotor of the motor is reset to the initial position, and the motor is soft-started, and during the soft-start process, the motor is commutated based on the identification result until the current value is not less than the current threshold, so that the motor is in a non-stationary state;

[0077] According to some embodiments, the current threshold refers to a threshold used to determine whether the motor is in a stationary state. For example, the current threshold may be 0. When the current value of the motor is equal to 0, it indicates that the motor is in a stationary state, otherwise it is in a non-stationary state.

[0078] In some embodiments, the rotor of the motor can be reset to the initial position by treating the A-phase winding as a powered phase and the BC-phase winding as a powered phase, that is, the current enters from the A-phase winding and is output from the BC-phase winding. The motor can also be rotated at a low speed to pre-position the rotor, that is, determine the initial position of the rotor.

[0079] According to some embodiments, soft starting refers to starting a motor by gradually increasing voltage or current to reduce current surge and torque fluctuation when the motor starts.

[0080] In some embodiments, when the motor is commutated based on the identification result during the soft start process, a second power supply voltage can be provided to the A-phase winding, B-phase winding and C-phase winding of the motor respectively, and the motor can be subjected to voltage and current detection to obtain a second three-phase voltage, a second three-phase current and a second bus voltage; the second three-phase zero-crossing point and the second voltage absolute value maximum point corresponding to the second three-phase voltage, the second three-phase current and the second bus voltage are identified; the second three-phase zero-crossing point is compared with the first three-phase zero-crossing point, and the second voltage absolute value maximum point is compared with the first voltage absolute value maximum point to obtain a comparison result; the pulse width modulation phase sequence corresponding to the comparison result is determined, and the motor is commutated according to the pulse width modulation phase sequence to maintain the movement of the motor.

[0081] In some embodiments, the second power supply voltage refers to a gradually increasing voltage received by the motor during a soft start process.

[0082] In some embodiments, the process of identifying the second three-phase zero-crossing point and the second voltage absolute value highest point corresponding to the second three-phase voltage, the second three-phase current and the second bus voltage can refer to the process of identifying the first three-phase zero-crossing point and the first voltage absolute value highest point of the motor through the first three-phase voltage, the first three-phase current and the first bus voltage in step S201, and will not be repeated here.

[0083] According to some embodiments, when the motor is commutated according to a pulse width modulation phase sequence to maintain the motion of the motor, an open loop control strategy may be used to control the motor according to a preset voltage or frequency curve until a current threshold is reached.

[0084] S203, when the motor is in a non-stationary state, determining the number of zero crossings of the three-phase signal of the motor within a preset time period at intervals of a preset time period;

[0085] It should be noted that for motors of different structures, the number of zero crossings detected at each preset time length may be different. For example, if the number of pole pairs of the motor is different, the number of zero crossings detected at each preset time length may also be different.

[0086] S204, when the number of zero crossings is less than the zero crossing number threshold, injecting a target signal into the stator winding of the motor, determining a zero crossing time interval of the three-phase signal of the motor after the target signal is injected, and determining a rotor position and a rotation speed of the motor according to the time interval;

[0087] According to some embodiments, the zero-crossing time interval is determined by the time interval between any two adjacent zero-crossing time points of the three-phase signal of the motor after the target signal is injected. The zero-crossing time interval can be obtained by detecting multiple time intervals and averaging them to improve the reliability of the zero-crossing time interval determination.

[0088] In some embodiments, when the frequency of the target signal is greater than a preset frequency, the target signal may be regarded as a high-frequency signal. The preset frequency may be determined according to actual application scenarios.

[0089] According to some embodiments, a sliding mode observer (SMO) or an extended Kalman filter (EKF) can be used to determine the rotor position and speed of the motor according to the time interval. Both SMO and EKF are algorithms for motor state estimation, which can provide estimates of the rotor position and speed, and maintain relatively smooth control even under low speed conditions.

[0090] Among them, SMO is a state observer of nonlinear systems. It forces the system state to reach the sliding surface and slide on it within a finite time by designing a sliding surface and a control law. SMO has good robustness to changes in system parameters and external disturbances, so it is widely used in motor control. It can quickly and accurately estimate the rotor position and speed of the motor, and can work effectively even in the presence of parameter uncertainty and external disturbances.

[0091] Among them, EKF is an extension of Kalman filter, which can be used to deal with the state estimation problem of nonlinear systems. EKF converts nonlinear problems into linear problems by linearizing the nonlinear equations of the system, thereby allowing the use of the Kalman filter framework to solve the state estimation problem of nonlinear systems. EKF Taylor expands the nonlinear function at each step (usually retains the first-order term), thereby approximating the nonlinear problem to a linear problem. This method enables EKF to effectively perform state estimation and tracking on nonlinear systems when the system and measurement model exhibit significant nonlinear characteristics.

[0092] In some embodiments, SMO and EKF can also be used in combination to determine the rotor position and speed of the motor based on the time interval to take advantage of their respective advantages. For example, EKF can be used to preliminarily estimate the electrical angle, and then SMO further optimizes the estimation result by introducing the sliding surface. Through this combination, a more accurate and stable electrical angle estimation can be achieved, thereby obtaining the target sinusoidal waveform, and then the rotor position and speed of the motor can be obtained.

[0093] S205, when the number of zero crossings is not less than the zero crossing number threshold, determining the number of times the absolute value of the voltage of the motor reaches the highest point of the absolute value of the voltage within a preset time length, and determining the rotor position and speed of the motor according to the number of zero crossings and the number of highest points;

[0094] It should be noted that when the number of zero crossings is not less than the zero crossing threshold, the back electromotive force of the motor is usually large enough to estimate the rotor position more accurately. Therefore, a closed-loop control strategy, such as vector control, can be used to directly determine the rotor position and speed of the motor based on the number of zero crossings and the number of highest points.

[0095] S206, obtaining the third three-phase voltage and the third three-phase current of the motor; determining the current reference value, the speed reference value and the rotor position reference value corresponding to the current loop of the motor; using the third three-phase current, the rotor position and the speed as inputs of the current loop, and using the third three-phase voltage as feedback of the current loop, and performing adaptive control on the current loop, so that the difference between the third three-phase current and the current reference value is less than a first difference threshold, the difference between the speed and the speed reference value is less than a second difference threshold, and the difference between the rotor position and the rotor position reference value is less than a third difference threshold.

[0096] According to some embodiments, when the third three-phase voltage is used as feedback of the current loop, the voltage signal of the third three-phase voltage can be decomposed with phase A as the x-axis, and then Clarke and Park transformations are performed in sequence to obtain the D-axis voltage and Q-axis voltage of the motor as feedback of the current loop.

[0097] In some embodiments, the current reference value, the speed reference value, the rotor position reference value, the first difference threshold value, the second difference threshold value, and the third difference threshold value can be adjusted according to actual application scenarios.

[0098] According to some embodiments, when performing PID regulation on the current loop, an adaptive control strategy may be adopted, that is, as the motor speed changes, the control parameters are dynamically adjusted to adapt to different operating conditions.

[0099] In some embodiments, an adaptive control strategy can identify model parameters of the controlled system. These parameters may change over time or as environmental conditions change. For example, a change in the load of a motor can cause its dynamic characteristics to change. Once the current system parameters are identified, the adaptive control strategy can adjust the control parameters to adapt to the new system characteristics. This adjustment can be in real time to ensure that the system always maintains optimal performance. Adaptive control enhances the robustness of motor control by dynamically adjusting parameters, enabling it to cope with external disturbances and internal parameter changes. With adaptive control, the motor can optimize its operating parameters at different speeds, thereby improving energy efficiency.

[0100] For example, during the operation of the motor, the load may change. Adaptive control can adjust the control parameters in real time to compensate for the impact of load changes on the motor speed, ensuring that the motor can operate stably under various load conditions.

[0101] In some embodiments, the adaptive control strategy includes but is not limited to a model reference adaptive control (MRAC) strategy, an adaptive PID control strategy, and the like.

[0102] Among them, MRAC is a commonly used adaptive control method. It uses a reference model to define the desired system behavior and adjusts the control parameters to make the actual system output as close as possible to the output of the reference model. In motor control, MRAC can be used to ensure that the motor can achieve the expected performance indicators at different speeds, such as response speed and steady-state error.

[0103] Among them, adaptive proportional-integral-derivative (PID) control automatically adjusts the proportional (P), integral (I) and derivative (D) parameters to adapt to system dynamic changes. This method is widely used in industrial control because it is simple and effective. The adaptive PID control strategy can adjust parameters based on performance indicators (such as error, response time) to optimize system performance.

[0104] According to some embodiments, when the motor is running, it may be subject to various disturbances (such as load changes, temperature effects, etc.). By observing these disturbances and compensating for them, the stability of the motor operation can be improved. Among them, at least one of the following methods can be used for observation and compensation:

[0105] Temperature compensation technology: The effect of temperature on motor performance can be compensated by monitoring the temperature changes of the motor and adjusting the motor control parameters, such as the rotor time constant, according to these changes.

[0106] Load observation and feedforward compensation: The load observer can monitor the changes in the motor load and use the observed load changes as interference for feedforward compensation, which can significantly improve the stability of the motor speed.

[0107] Disturbance observer: A disturbance observer can be designed to monitor the internal parameter perturbations and external load disturbances of the motor in real time, and feed forward the observed values ​​to the current loop adaptive sliding mode controller to improve the robustness of the motor control while reducing the jitter of the current loop adaptive sliding mode controller.

[0108] Non-singular terminal sliding mode control: Design a non-singular terminal sliding mode velocity loop controller based on the nonlinear sliding surface to ensure the convergence of the system in finite time, while avoiding the singular problem of the system, reducing the system's chattering, and improving the steady-state accuracy of the system.

[0109] Improved sliding mode disturbance observer: The improved disturbance observer is used to observe and estimate the motor disturbance in real time, and the estimated disturbance is fed back to the PI regulator for feedforward compensation, which effectively improves the motor control performance and alleviates the jitter phenomenon.

[0110] Current predictive control: By building a state observer to observe the parameter errors and parameter disturbances in the servo system, the motor current predictive control based on disturbance observation and compensation is improved to improve the robustness of the algorithm and avoid steady-state current errors caused by parameter deviations and parameter disturbances.

[0111] In some embodiments, by using the above methods individually or in combination, the disturbances to which the motor is subjected when running at high speed can be effectively observed and compensated, thereby improving the stability and performance of the motor, and significantly improving the performance and reliability of the sensorless motor system. The present application does not limit the combination of the observation and compensation methods.

[0112] In summary, the method provided in this embodiment has the characteristics of sensorless control of normal operation of the motor, solves the problem of smooth start, low-speed operation and high-speed operation of the motor of the sensorless system, and ensures that the motor works reliably under different working conditions (including low-speed operation state and high-speed operation state). Secondly, by detecting the zero crossing point and the highest point of the absolute value of the voltage, as the basis for commutation and speed calculation and position calculation, it is conducive to adjusting the performance of the motor under different working conditions, and can be applied to different application occasions, ensuring the reliable operation of the motor at low speed and high speed. In addition, the intelligent scheme for controlling the continuous rotation of the rotor in the related art (for example: square wave control, sine wave control) cannot be controlled adaptively according to the rotor position, and the torque fluctuation is large and the efficiency is low. The present disclosure performs PID adjustment parameters according to the motor speed, position and current, which can realize more reliable PID adjustment capability, and can provide larger electromagnetic torque and smaller switching loss in the process of controlling the operation of the encoderless motor, without encoder, saving cost, realizing sensorless control of the motor, improving the motor control accuracy, good adaptability and strong robustness.

[0113] In order to implement the above embodiments, the present disclosure also proposes a sensorless motor control system.

[0114] For example, Figure 2 FIG. 1 is a schematic diagram of a sensorless motor control system provided by an embodiment of the present disclosure. Figure 2 As shown, the sensorless motor control system 200 includes:

[0115] The zero-crossing detection unit 210 is used to determine the number of zero-crossings of the three-phase signal of the motor within a preset time period at intervals of a preset time period when the motor is in a non-stationary state;

[0116] The parameter determination unit 220 is used to perform back electromotive force detection on the motor when the number of zero crossings is less than the zero crossing number threshold, and determine the rotor position and speed of the motor according to the back electromotive force detection result;

[0117] The motor control unit 230 is used to control the motor according to the rotor position and speed.

[0118] Optionally, before the motor is in a non-stationary state, the sensorless motor control system 200 further includes:

[0119] The motor identification unit 240 is used to identify the phase sequence and parameters of the motor, and detect the current value of the motor when the identification result meets the phase sequence and parameter requirements;

[0120] The motor starting unit 250 is used to reset the rotor of the motor to an initial position and perform soft start on the motor if the current value is less than the current threshold, and perform commutation operation on the motor based on the identification result during the soft start process until the current value is not less than the current threshold, so that the motor is in a non-stationary state.

[0121] Optionally, the motor identification unit 240 includes a phase sequence identification subunit 241, a parameter detection subunit 242, a waveform determination subunit 243 and a parameter identification subunit 244. The motor identification unit 240 is used to perform phase sequence and parameter identification on the motor:

[0122] The phase sequence identification subunit 241 is used to identify the phase sequence of the motor and determine the A-phase winding, the B-phase winding and the C-phase winding of the motor, wherein the A-phase winding leads the B-phase winding by 120 degrees, and the B-phase winding leads the C-phase winding by 120 degrees;

[0123] The parameter detection subunit 242 is used to sequentially provide a first power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor, and perform voltage and current detection on the motor to obtain a first three-phase voltage, a first three-phase current and a first bus voltage;

[0124] The waveform determination subunit 243 is used to calculate the motor speed, the digitized rotation angle signal and the current value through the first three-phase voltage, the first three-phase current and the first bus voltage based on the magnetic field oriented control strategy to obtain a three-phase pulse width modulation waveform;

[0125] The parameter identification subunit 244 is used to perform proportional-integral control on the motor according to the three-phase pulse width modulation waveform, and to identify the first three-phase zero-crossing point and the first voltage absolute value maximum point of the motor during the proportional-integral control process.

[0126] Optionally, the motor starting unit 250 is used to perform a commutation operation on the motor based on the identification result during the soft starting process, specifically for:

[0127] Providing a second power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor respectively in sequence, and performing voltage and current detection on the motor to obtain a second three-phase voltage, a second three-phase current and a second bus voltage;

[0128] Identify the second three-phase zero-crossing point and the second voltage absolute value maximum point corresponding to the second three-phase voltage, the second three-phase current and the second bus voltage;

[0129] Compare the second three-phase zero-crossing point with the first three-phase zero-crossing point, and compare the second voltage absolute value maximum point with the first voltage absolute value maximum point to obtain a comparison result;

[0130] A pulse width modulation phase sequence corresponding to the comparison result is determined, and a commutation operation is performed on the motor according to the pulse width modulation phase sequence.

[0131] Optionally, the parameter determination unit 220 is used to detect the back electromotive force of the motor and determine the rotor position and speed of the motor according to the back electromotive force detection result, specifically for:

[0132] Injecting a target signal into the stator winding of the motor, and determining a zero-crossing time interval of the three-phase signal of the motor after the target signal is injected, wherein the zero-crossing time interval is determined by the time interval between any two adjacent zero-crossing time points of the three-phase signal of the motor after the target signal is injected, wherein the frequency of the target signal is greater than a preset frequency;

[0133] The rotor position and speed of the motor are determined based on the time interval.

[0134] Optionally, after determining the number of zero crossings of the three-phase signal of the motor within a preset time length, the parameter determination unit 220 is further used to:

[0135] When the number of zero crossings is not less than the zero crossing number threshold, determining the number of times the absolute value of the voltage of the motor reaches the highest point of the absolute value of the voltage within a preset time period;

[0136] The rotor position and speed of the motor are determined based on the number of zero crossings and the number of peak points.

[0137] Optionally, when the motor control unit 230 is used to control the motor according to the rotor position and the speed, it is specifically used to:

[0138] Obtain the third three-phase voltage and the third three-phase current of the motor;

[0139] Determine a current reference value, a speed reference value, and a rotor position reference value corresponding to a current loop of the motor;

[0140] The third three-phase current, rotor position and speed are used as inputs of the current loop, and the third three-phase voltage is used as feedback of the current loop. The current loop is adaptively controlled so that the difference between the third three-phase current and the current reference value is less than a first difference threshold, the difference between the speed and the speed reference value is less than a second difference threshold, and the difference between the rotor position and the rotor position reference value is less than a third difference threshold.

[0141] It should be noted that the above explanation of the embodiment of the sensorless motor control method is also applicable to the sensorless motor control system of this embodiment, and will not be repeated here.

[0142] In summary, the system provided by the embodiments of the present invention detects the zero-crossing point of the three-phase signal as a basis for the low-speed or zero-speed operation of the motor, and performs back-electromotive force detection on the motor when the motor is running at low speed or zero speed, and determines the rotor position and speed of the motor according to the back-electromotive force detection result. This can reduce the problem of poor control effect caused by low accuracy of stator voltage calculation, improve the motor control accuracy of the sensorless motor, and enhance the stability of the sensorless motor during operation.

[0143] In order to implement the above embodiments, the present disclosure also proposes an electronic product, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0144] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0145] In order to implement the above embodiments, the present disclosure also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0146] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this disclosure shall comply with the relevant laws and regulations and shall not violate public order and good morals.

[0147] It should be noted that personal information from users should be collected for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. In addition, such collection / sharing should be carried out after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign the agreement / authorization including authorization of relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others who have access to personal information data comply with its privacy policy and procedures.

[0148] The present disclosure anticipates providing implementation schemes for users to selectively block the use or access of personal information data. That is, the present disclosure anticipates providing hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, risks can be minimized by limiting data collection and deleting the data. In addition, when applicable, such personal information is de-identified to protect the privacy of the user.

[0149] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0150] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0151] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present disclosure belong.

[0152] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM) or flash memory, an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0153] It should be understood that the various parts of the present disclosure can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0154] A person skilled in the art may understand that all or part of the steps in the above-mentioned embodiment method may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0155] In addition, each functional unit in each embodiment of the present disclosure may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0156] The storage medium mentioned above may be a read-only memory, a disk or an optical disk, etc. Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present disclosure. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present disclosure.

Claims

1. A sensorless motor control method, characterized in that: include: When the motor is in a non-stationary state, at every preset time length, determining the number of zero crossings of the three-phase signal of the motor within the preset time length; When the number of zero crossings is less than a zero crossing threshold, back electromotive force detection is performed on the motor, and a rotor position and a rotation speed of the motor are determined according to the back electromotive force detection result; The motor is controlled according to the rotor position and the rotational speed.

2. The method according to claim 1, characterized in that When the motor is in a non-stationary state, before determining the number of zero crossings of the three-phase signal of the motor within the preset time period at every preset time period, the method further includes: Performing phase sequence and parameter identification on the motor, and detecting the current value of the motor when the identification result meets the phase sequence and parameter requirements; If the current value is less than the current threshold, the rotor of the motor is reset to an initial position, and the motor is soft-started. During the soft-start process, the motor is commutated based on the identification result until the current value is not less than the current threshold, so that the motor is in a non-stationary state.

3. The method according to claim 2, characterized in that The phase sequence and parameter identification of the motor includes: Performing phase sequence identification on the motor to determine the A-phase winding, the B-phase winding, and the C-phase winding of the motor, wherein the A-phase winding leads the B-phase winding by 120 degrees, and the B-phase winding leads the C-phase winding by 120 degrees; Providing a first power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor respectively in sequence, and performing voltage and current detection on the motor to obtain a first three-phase voltage, a first three-phase current and a first bus voltage; Obtain a three-phase pulse width modulation waveform by calculating the motor speed, the digitized rotation angle signal and the current value through the first three-phase voltage, the first three-phase current and the first bus voltage based on a magnetic field oriented control strategy; The motor is subjected to proportional-integral control according to the three-phase pulse width modulation waveform, and during the proportional-integral control, a first three-phase zero-crossing point and a first voltage absolute value maximum point of the motor are identified.

4. The method according to claim 3, characterized in that The performing a commutation operation on the motor based on the identification result during the soft start process includes: Providing a second power supply voltage to the A-phase winding, the B-phase winding and the C-phase winding of the motor in sequence, and performing voltage and current detection on the motor to obtain a second three-phase voltage, a second three-phase current and a second bus voltage; Identify the second three-phase zero-crossing point and the second voltage absolute value maximum point corresponding to the second three-phase voltage, the second three-phase current and the second bus voltage; Compare the second three-phase zero-crossing point with the first three-phase zero-crossing point, and compare the second voltage absolute value maximum point with the first voltage absolute value maximum point to obtain a comparison result; A pulse width modulation phase sequence corresponding to the comparison result is determined, and a commutation operation is performed on the motor according to the pulse width modulation phase sequence.

5. The method according to claim 1, characterized in that The step of performing back electromotive force detection on the motor and determining the rotor position and rotation speed of the motor according to the back electromotive force detection result includes: Injecting a target signal into the stator winding of the motor, and determining a zero-crossing time interval of the three-phase signal of the motor after the target signal is injected, wherein the zero-crossing time interval is determined by the time interval between any two adjacent zero-crossing time points of the three-phase signal of the motor after the target signal is injected, wherein the frequency of the target signal is greater than a preset frequency; The rotor position and the rotation speed of the motor are determined based on the time interval.

6. The method according to claim 1, characterized in that After determining the number of zero crossings of the three-phase signal of the motor within the preset time length, the method further includes: When the number of zero crossings is not less than the zero crossing threshold, determining the number of times the absolute value of the voltage of the motor reaches the highest point of the absolute value of the voltage within the preset time period; The rotor position and the rotation speed of the motor are determined according to the zero-crossing times and the peak point times.

7. The method according to claim 1, characterized in that The controlling the motor according to the rotor position and the speed includes: Obtaining a third three-phase voltage and a third three-phase current of the motor; Determine a current reference value, a speed reference value, and a rotor position reference value corresponding to a current loop of the motor; The third three-phase current, the rotor position and the speed are used as inputs of the current loop, and the third three-phase voltage is used as feedback of the current loop, and the current loop is adaptively controlled so that the difference between the third three-phase current and the current reference value is less than a first difference threshold, the difference between the speed and the speed reference value is less than a second difference threshold, and the difference between the rotor position and the rotor position reference value is less than a third difference threshold.

8. A sensorless motor control system, characterized in that: include: A zero-crossing detection unit, used for determining the number of zero-crossings of the three-phase signal of the motor within a preset time period at intervals of a preset time period when the motor is in a non-stationary state; a parameter determination unit, configured to perform back electromotive force detection on the motor when the number of zero crossings is less than a zero crossing number threshold, and determine a rotor position and a rotation speed of the motor according to the back electromotive force detection result; A motor control unit is used to control the motor according to the rotor position and the rotation speed.

9. An electronic product, characterized in that: The electronic products include: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory, so that the electronic product executes 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 stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 7 is implemented.

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