Online estimation method and system for stator flux linkage of permanent magnet synchronous motor

Abstract

The embodiment of the invention provides a permanent magnet synchronous motor stator flux linkage online estimation method and system, and belongs to the technical field of permanent magnet synchronous motor control. The rotating speed information of the permanent magnet synchronous motor is acquired; selecting corresponding correction parameters according to the rotating speed information; according to the rotating speed information and the correction parameter, obtaining an online estimated stator flux linkage axis component; and obtaining a stator flux linkage estimation value according to the stator flux linkage axis component. The system hardware cost and the experiment time cost can be reduced, the identification process is simplified, and the identification efficiency and accuracy are improved.

Description

Technical Field

[0001] The present application relates to the technical field of permanent magnet synchronous motor control, and in particular to a method and system for online estimation of stator flux of a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motor (PMSM) has the advantages of small size, high power density and high efficiency. To achieve high-precision torque or speed control, PMSM generally adopts vector control. In recent years, in order to save costs and avoid control failure caused by failure of rotary encoders under certain harsh working conditions, vector control solutions without rotary encoders have gradually become mainstream.

[0003] At present, there are two main ways to obtain the stator flux of permanent magnet synchronous motors. One is offline flux identification. Through experimental measurement, the motor is dragged back by a dynamometer under no-load condition to measure the back electromotive force at different speeds. Then, based on the relationship between flux and speed, the stator flux of the motor is finally obtained based on the basic voltage equation. The disadvantage of this method is that it requires the construction of a special test environment, including a dynamometer, test equipment, etc., which is costly, time-consuming, and complicated in actual operation. Different motors for different projects need to be retested and measured, which is a huge workload and has poor portability. The second method is online flux identification. During the operation of the motor, the stator flux is identified online through flux observers such as extended Kalman filter, model reference adaptive method, voltage model, current model, and hybrid model. However, the extended Kalman filter requires a large number of complex inversion operations, with poor real-time performance and slow response speed; the design process of the model reference adaptive method is complex and difficult to implement in actual engineering; the voltage model, current model and hybrid model, the estimation accuracy of the current model is affected by the temperature rise of the motor and the saturation of the magnetic circuit; the voltage model has problems such as initial value error and DC bias due to the pure integral link. Summary of the invention

[0004] The main purpose of the embodiments of the present application is to provide a method and system for online estimation of the stator flux of a permanent magnet synchronous motor.

[0005] The technical solution adopted by the present invention is:

[0006] On the one hand, an embodiment of the present invention provides a method for online estimation of stator flux of a permanent magnet synchronous motor, the method comprising the following steps:

[0007] Get the speed information of the permanent magnet synchronous motor;

[0008] Selecting corresponding correction parameters according to the speed information;

[0009] Obtaining an online estimated stator flux axis component according to the speed information and the correction parameter;

[0010] A stator flux estimation value is obtained according to the stator flux axial component.

[0011] Furthermore, the obtaining of the speed information of the permanent magnet synchronous motor comprises the following steps:

[0012] Set the speed threshold;

[0013] According to the speed threshold, a speed region is obtained;

[0014] According to the rotation speed range, rotation speed information is obtained.

[0015] Furthermore, the corresponding correction parameter is selected according to the size of the speed information, and the formula used includes:

[0016]

[0017] Among them, α1 is the first speed threshold; α2 is the second speed threshold; ω r is the angular velocity of the motor; g(ω r ) is the correction parameter with the motor speed as the independent variable.

[0018] Furthermore, the formula used to obtain the online estimated stator flux axis component based on the speed information and the correction parameter includes:

[0019]

[0020] is the α-axis component of the stator flux estimated online by the current model;

[0021] is the stator flux β-axis component estimated online by the current model;

[0022] It is the stator flux α-axis component estimated online by the improved voltage model;

[0023] It is the stator flux β-axis component estimated online by the improved voltage model;

[0024] ψ sα It is the stator flux α-axis component output by the estimation model;

[0025] ψ sβ It is the stator flux β-axis component output by the estimated model.

[0026] Furthermore, the formula used in the current model includes:

[0027]

[0028] in, is the current model in the two-phase stationary coordinate system;

[0029] θ is the rotation angle of the motor rotor;

[0030] L d is the inductance of the d-axis in the rotating coordinate system;

[0031] i d is the current of the d-axis in the rotating coordinate system;

[0032] is the magnetic flux of the rotor permanent magnet;

[0033] L q is the inductance of the q-axis in the rotating coordinate system;

[0034] i q is the current along the q axis in the rotating coordinate system.

[0035] Furthermore, the method for online estimating the stator flux of a permanent magnet synchronous motor further comprises the following steps:

[0036] Set the high-pass filter;

[0037] According to the high-pass filter and the integrator, a transfer function is obtained;

[0038] According to the transfer function, an improved voltage model is obtained.

[0039] Furthermore, the transfer function is obtained according to the high-pass filter and the integrator, and the formula used includes:

[0040]

[0041] in, is the transfer function;

[0042] ω c is the cut-off angular frequency of the integrator;

[0043] E s (s) is the back electromotive force of the motor;

[0044] s is the complex frequency domain variable in the Laplace transform.

[0045] On the other hand, an embodiment of the present invention further provides a permanent magnet synchronous motor stator flux online estimation system, the system comprising:

[0046] The first module is used to obtain the speed information of the permanent magnet synchronous motor;

[0047] The second module is used to select a corresponding correction parameter according to the speed information;

[0048] A third module is used to obtain an online estimated stator flux axis component according to the speed information and the correction parameter;

[0049] The fourth module is used to obtain a stator flux estimation value according to the stator flux axis component.

[0050] On the other hand, an embodiment of the present invention also provides an online estimation device for the stator flux of a permanent magnet synchronous motor, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the online estimation method for the stator flux of the permanent magnet synchronous motor as described above is implemented.

[0051] On the other hand, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the method described above.

[0052] The embodiments of the present application include at least the following beneficial effects: The present application provides a method and system for online estimation of the stator flux of a permanent magnet synchronous motor. The present invention obtains the speed information of the permanent magnet synchronous motor; selects corresponding correction parameters according to the size of the speed information; obtains the online estimated stator flux axis component according to the speed information and the correction parameters; obtains the stator flux estimation value according to the stator flux axis component. The present invention can reduce the system hardware cost and experimental time cost, simplify the identification process, and improve the identification efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a flow chart of a method for online estimation of stator flux of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0054] Figure 2 is a flow chart of a method for online estimation of stator flux of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0055] Figure 3 is a flow chart of a method for online estimation of stator flux of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0056] Figure 4 is a flow chart of a method for online estimation of stator flux of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0057] Figure 5 is a flow chart of a method for online estimation of stator flux of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0058] Figure 6 is a schematic diagram of an online estimation system for stator flux linkage of a permanent magnet synchronous motor provided by an embodiment of the present invention;

[0059] Figure 7It is a working flow chart of a hybrid stator flux online estimator based on speed provided by an embodiment of the present invention;

[0060] Figure 8 is a structural diagram of a hybrid stator flux online estimator provided by an embodiment of the present invention;

[0061] Fig. 9 This is a specific block diagram after adding a feedback compensation module provided by an embodiment of the present invention;

[0062] Fig.10 It is a schematic diagram of the hardware structure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0064] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

[0065] The terms "at least one", "multiple", "each", "any", etc. used in this application, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0067] The present invention takes into account that there are two main ways to obtain the stator flux of a permanent magnet synchronous motor. One is offline flux identification, which relies on the basic voltage equation of the motor to obtain the stator flux through experimental measurement, but requires the construction of a special test environment, including a dynamometer, test equipment, etc., which is costly, time-consuming, and complicated in actual operation. The other is online flux identification. During the operation of the motor, the stator flux is identified online through flux observers such as an extended Kalman filter, a model reference adaptive method, a voltage model, a current model, and a hybrid model. However, the extended Kalman filter requires a large number of complex inversion operations, poor real-time performance, and slow response speed; the model reference adaptive method has a complex design process and is difficult to implement in actual engineering; the estimation accuracy of the voltage model, the current model, and the hybrid model is affected by the temperature rise of the motor and the saturation of the magnetic circuit; the voltage model has problems such as integral initial value error and DC bias due to the pure integral link. Therefore, it is necessary to develop a relatively simple online identification method for the stator flux of a PMSM to reduce the system hardware cost and experimental time cost, simplify the identification process, and improve the identification efficiency and accuracy.

[0068] The present invention takes a permanent magnet synchronous motor as a research object, and adopts a speed-based hybrid stator flux observer to obtain the stator flux in the current state for the current, voltage, etc. of the motor in the current state. In view of the problem that a single current or voltage model has poor estimation accuracy in the full speed range of the motor, a correction module with the actual motor speed as the independent variable is designed to realize the hybrid stator flux online estimator, in which the current model works at low speed; at high speed, the voltage model works; when switching between high and low speeds, that is, in the medium speed range of the motor, a linear function of the speed is used to realize smooth switching of stator flux observation, solving the problem that the traditional hybrid flux observer has relatively poor robustness in the medium speed range. Furthermore, in order to solve the problem of DC bias in the traditional voltage model, the present invention proposes an improved voltage model, and adds a high-pass filter to solve the DC bias problem. Since the high-pass filter will have amplitude attenuation and phase error when observing the stator flux, a feedback compensation module is added to realize error compensation for amplitude and phase.

[0069] Before describing the embodiments of the present application in detail, some nouns and terms involved in the embodiments of the present application are first described. The nouns and terms involved in the embodiments of the present application are subject to the following explanations.

[0070] 1) Permanent Magnet Synchronous Motor (PMSM): It is an AC motor that uses permanent magnets as the rotor magnetic field.

[0071] 2) Kalman Filter: It is a recursive filtering algorithm used to estimate the state of a dynamic system.

[0072] 3) Stator flux: It is the flux formed by the interaction between the magnetic field generated in the motor stator winding and the magnetic field generated by the permanent magnet. It is a key electromagnetic quantity in the operation of the motor and affects the performance and efficiency of the motor.

[0073] 4) Pure integrator: In motor control, especially when voltage models are involved, pure integrator usually refers to a mathematical model used to describe the change of state variables in a dynamic system. Specifically, the function of the integrator is to integrate the input signal (such as current, speed, etc.) to obtain the state variables of the system (such as voltage, displacement, etc.).

[0074] 5) High-pass filter: An electronic filter that allows high-frequency signals to pass through while attenuating low-frequency signals.

[0075] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0076] On the one hand, an embodiment of the present invention provides a method for online estimation of stator flux of a permanent magnet synchronous motor, referring to Figure 1 , the method comprises the following steps:

[0077] S100, obtaining speed information of the permanent magnet synchronous motor;

[0078] S200, selecting corresponding correction parameters according to the speed information;

[0079] S300, obtaining an online estimated stator flux axial component according to the speed information and the correction parameter;

[0080] S400: Obtain a stator flux estimation value according to a stator flux axial component.

[0081] The embodiment of the present invention discloses step S100 to obtain the speed information of the permanent magnet synchronous motor, referring to Figure 2 , including the following steps:

[0082] S110, setting a speed threshold;

[0083] S120, obtaining a speed range according to a speed threshold;

[0084] S130: Obtain speed information according to the speed range.

[0085] As an optional implementation, the present invention selects a suitable rotation speed sensor, such as an encoder or a Hall sensor, to obtain the rotation speed of the motor with high precision.

[0086] The embodiment of the present invention compares the rotation speed monitored in real time with a set threshold value.

[0087] If the current speed is less than the first threshold (6000 rpm), it is determined to be in a low speed zone.

[0088] If the current rotation speed is ≥ the first threshold and < the second threshold (10000 rpm), it is determined to be in the medium speed zone.

[0089] If the current rotation speed is ≥ the second threshold (10000 rpm), it is determined to be in the high speed zone.

[0090] According to the confirmed speed range, the corresponding information processing module is activated. The processing strategies for different areas are different:

[0091] In the low speed area, the current model processing is activated.

[0092] In the medium speed region, hybrid model processing is activated.

[0093] In the high-speed area, voltage model processing is activated.

[0094] The embodiment of the present invention discloses that step S200 selects a corresponding correction parameter according to the size of the speed information, and the formula used includes:

[0095]

[0096] Among them, α1 is the first speed threshold; α2 is the second speed threshold; ω r is the angular velocity of the motor; g(ω r ) is the correction parameter with the motor speed as the independent variable.

[0097] As an optional implementation, the present invention determines whether the motor is currently in a low speed zone, a medium speed zone, or a high speed zone:

[0098] Low speed range: [0,6000]RPM;

[0099] Medium speed area: [6000,10000]RPM;

[0100] High speed area: [10000,18000]RPM;

[0101] refer to Figure 3 , according to the preset threshold, determine the correction parameter corresponding to the current state of the motor, calibrate the first threshold and the second threshold to ensure smooth switching in different intervals:

[0102] The first threshold (the critical point for switching between the low speed zone and the medium speed zone): 6000rpm;

[0103] The second threshold (the critical point for switching between the medium speed zone and the high speed zone): 10000rpm;

[0104] According to the motor state and speed range, configure the parameters of the correction module. These parameters will affect the switching and fusion process of the current model and voltage model.

[0105] The embodiment of the present invention discloses that step S300 obtains the stator flux axis component estimated online according to the speed information and the correction parameter, and the formula used includes:

[0106]

[0107] is the α-axis component of the stator flux estimated online by the current model;

[0108] is the stator flux β-axis component estimated online by the current model;

[0109] It is the stator flux α-axis component estimated online by the improved voltage model;

[0110] It is the stator flux β-axis component estimated online by the improved voltage model;

[0111] ψ sα It is the stator flux α-axis component output by the estimation model;

[0112] ψ sβ It is the stator flux β-axis component output by the estimated model.

[0113] As an optional implementation, refer to Figure 4 , embodiments of the present invention:

[0114] The real-time data of the motor is input into the set estimation model to perform online estimation calculations.

[0115] Based on the model structure and inputs, an estimate of the stator flux is calculated. This usually involves processing the current and voltage signals and adjusting them in combination with correction parameters.

[0116] After obtaining the stator flux estimation value, the result is monitored in real time. If abnormal values ​​are found, the model parameters are adjusted or the model is switched through the feedback mechanism to improve the stability and accuracy of the estimation.

[0117] The formula used in the current model disclosed in the embodiment of the present invention includes:

[0118]

[0119] in, is the current model in the two-phase stationary coordinate system;

[0120] θ is the rotation angle of the motor rotor;

[0121] Ld is the inductance of the d-axis in the rotating coordinate system;

[0122] i d is the current of the d-axis in the rotating coordinate system;

[0123] is the magnetic flux of the rotor permanent magnet;

[0124] L q is the inductance of the q-axis in the rotating coordinate system;

[0125] i q is the current along the q axis in the rotating coordinate system.

[0126] The method for online estimation of stator flux of a permanent magnet synchronous motor disclosed in the embodiment of the present invention is referred to Figure 5 , further comprising the following steps:

[0127] S500, set high pass filter;

[0128] S600, obtaining a transfer function according to a high-pass filter and an integrator;

[0129] S700: Obtain an improved voltage model according to the transfer function.

[0130] The embodiment of the present invention discloses that step S600 obtains a transfer function according to a high-pass filter and an integrator, and the formula used includes:

[0131]

[0132] in, is the transfer function;

[0133] ω c is the cut-off angular frequency of the integrator;

[0134] E s (s) is the back electromotive force of the motor;

[0135] s is the complex frequency domain variable in the Laplace transform.

[0136] On the other hand, reference Figure 6 The embodiment of the present invention further provides a permanent magnet synchronous motor stator flux online estimation system, the system comprising:

[0137] The first module is used to obtain the speed information of the permanent magnet synchronous motor;

[0138] The second module is used to select corresponding correction parameters according to the speed information;

[0139] The third module is used to obtain an online estimated stator flux axis component according to the speed information and the correction parameter;

[0140] The fourth module is used to obtain a stator flux estimation value according to the stator flux axis component.

[0141] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0142] As an optional implementation, the present invention discloses a method for online estimation of stator flux of a permanent magnet synchronous motor, comprising:

[0143] 1. According to the actual speed of PMSM, a correction module with the actual speed of the motor as the independent variable is designed to realize the hybrid stator flux online estimator. The current model works at low speed; at high speed, the voltage model works; when switching between high and low speed, the stator flux estimation model is smoothly switched based on the correction module. The main stator flux estimation methods for PMSM currently include current model, voltage model, etc. The current model in the two-phase stationary coordinate system is shown as follows:

[0144]

[0145] This method has large amount of calculation and complex structure. In addition, the current model structure built according to the coordinate transformation and magnetic flux formula is as follows:

[0146]

[0147] After Park inverse transformation, the current model in the two-phase stationary coordinate system is obtained:

[0148]

[0149] The current model is greatly affected by the motor winding temperature and flux saturation at high speeds and is suitable for the low speed stage.

[0150] In the two-phase stationary coordinate system, the PMSM stator flux estimation model based on the voltage model is as follows:

[0151]

[0152] The advantage of the voltage model is that the calculation process is very simple and easy to implement, but it requires the motor stator resistance parameters. The flux observation error caused by the change of stator resistance is particularly obvious in the low-speed zone. Specifically, it is significantly affected by the stator resistance voltage drop, and a small change in resistance may lead to a significant decrease in observation accuracy; in the high-speed zone, the stator resistance voltage drop is very small and can be ignored, so it has good flux observation accuracy.

[0153] Based on the above analysis, the present invention proposes a hybrid stator flux online estimator based on speed. The estimation process is as follows: Figure 7 Workflow diagram of the speed-based hybrid stator flux online estimator.

[0154] 2. To realize the judgment of the speed, different stator flux estimation models are adopted according to different speed ranges to realize high-precision observation of stator flux. The present invention designs a speed range judgment module, and divides the full speed range of the motor into three different areas: low speed area, medium speed area, and high speed area. Taking the maximum speed of the motor of 18000rpm as an example, the low speed area can be set to [0,6000]rpm, the medium speed range is [6000,10000]rpm, and the high speed range is [10000,18000]rpm. The corresponding calibration preset threshold α1 is 6000rpm, and the preset threshold α2 is 10000rpm. The threshold is pre-written into the model through the underlying program, and the threshold of different motors can be adjusted according to actual conditions. In order to realize the smooth switching of the estimation model of high and low speed areas and improve the robustness of the observer, the present invention designs the following correction module:

[0155]

[0156] The formula involves two speed thresholds α1 and α2. The threshold when the current model estimation accuracy is reduced is defined as the first threshold α1, and the threshold when the voltage model estimation accuracy is fully obtained is defined as the second threshold α2. From α1 to α2, g(ω r ) is the speed ω r is a linear function of the independent variable. 0≤ω r <α1 is the low speed zone, and the corresponding correction parameter of the correction module in the low speed zone is g(ω r )=2πα1,α1≤ω r <α2 is the medium speed zone, and the corresponding correction parameter of the correction module in the medium speed zone is g(ω r )=ω r ,ω r ≥α2 is the high speed zone, and the corresponding correction parameter of the correction module in the high speed zone is g(ω r )=0.

[0157] The hybrid stator flux online estimator based on the above correction module is designed as follows. The voltage model is the best at high speed, and the current model is the best at low speed. There is a model switching process in the process of switching from low speed to high speed. The instantaneous switching may have a greater impact on the control system. Therefore, the present invention proposes a hybrid stator flux online estimator with motor speed as the independent variable. The specific form is as follows:

[0158]

[0159] In the formula, g(ωr ) are three different correction parameters within the full speed range of the correction module; They are the stator flux components estimated online by the current model; They are the stator flux components estimated online by the improved voltage model respectively.

[0160] 1) When 0≤ω r <α1, that is, in the low speed zone, g(ω r )=2πα1, at this time, the hybrid stator flux online estimator outputs the flux as follows:

[0161]

[0162] When the motor is running at low speed, at this time:

[0163]

[0164] 2) When α1≤ω r <α2, i.e. in the medium speed range, g(ω r )=ω r At this time, the hybrid stator flux online estimator outputs the flux as follows:

[0165]

[0166] The flux output of the hybrid model is ω r , The three are linear functions, and the speed is continuous, so the model can transition smoothly. Compared with the traditional method of switching through PI control, this method is simple, easy to implement, and has good robustness.

[0167] 3) When ω r ≥α2, i.e. in high speed zone, g(ω r )=0, at this time, the hybrid stator flux online estimator outputs the flux as follows:

[0168]

[0169] Combining the above design process, the structure diagram of the hybrid stator flux online estimator is as follows: Figure 8 .

[0170] 3. The traditional voltage model is a pure integrator. The DC component in the back electromotive force will form a DC bias after integration. To solve this problem, a high-pass filter is added on the basis of the pure integrator. The low-frequency signal is cut off by the high-pass filter, and the DC bias can be eliminated by integration. The corresponding transfer function is as follows:

[0171]

[0172] Simplified:

[0173]

[0174] Where: c is the cut-off angular frequency of the integrator; E s (s) is the back electromotive force of the motor.

[0175] The amplitude-frequency and phase-frequency characteristics of the high-pass filter at low speed are as follows:

[0176]

[0177] It can be seen that the high-pass filter will have the problem of amplitude attenuation and phase error when observing the stator flux. In order to solve this problem, the present invention adds a feedback compensation module to achieve amplitude and phase error compensation. The specific block diagram is as follows: Fig. 9 As shown, the feedback ensures the accuracy of the flux phase angle through coordinate conversion, that is, the conversion between the Cartesian coordinate system and the polar coordinate system, and the limiting module can suppress the amplitude attenuation problem, wherein the amplitude of the limiting module is usually set to the stator flux given value.

[0178] The key points of the present invention are:

[0179] 1. The embodiment of the present invention proposes a hybrid stator flux online estimator with motor speed as an independent variable, so that the current model takes effect at low speed; at high speed, the voltage model takes effect; when switching between high and low speed, smooth switching of the stator flux estimation model is achieved based on the correction module; the accuracy of flux estimation can be effectively improved.

[0180] 2. The present invention designs a correction module based on the actual speed of the motor, and provides correction parameters corresponding to low-speed, medium-speed and high-speed areas, which can be used as guiding parameters.

[0181] 3. This patent aims to solve the problem of amplitude attenuation and phase error in the stator flux observed by high-pass filter, and adds a feedback compensation module to realize amplitude and phase error compensation.

[0182] On the other hand, an embodiment of the present invention also provides an online estimation device for the stator flux of a permanent magnet synchronous motor, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the online estimation method for the stator flux of a permanent magnet synchronous motor as described above is implemented.

[0183] The device for online estimation of stator flux linkage of a permanent magnet synchronous motor according to an embodiment of the present invention includes a memory and a processor.

[0184] refer to Fig.10The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0185] The memory may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage. Among them, ROM can store static data or instructions required by the processor or other modules of the computer. The permanent storage device may be a readable and writable storage device. The permanent storage device may be a non-volatile storage device that does not lose the stored instructions and data even after the computer is powered off. In some embodiments, the permanent storage device uses a large-capacity storage device (such as a magnetic or optical disk, flash memory) as a permanent storage device. In some other embodiments, the permanent storage device may be a removable storage device (such as a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as a dynamic random access memory. The system memory may store some or all instructions and data required by the processor at run time. In addition, the memory may include any combination of computer-readable storage media, including various types of semiconductor memory chips (DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and disks and / or optical disks may also be used. In some embodiments, the memory may include a readable and / or writable removable storage device, such as a laser disc (CD), a read-only digital versatile disc (e.g., DVD-ROM, double-layer DVD-ROM), a read-only Blu-ray disc, an ultra-density optical disc, a flash memory card (e.g., SD card, mini SD card, Micro-SD card, etc.), a magnetic floppy disk, etc. The computer-readable storage medium does not include carrier waves and transient electronic signals transmitted wirelessly or wired.

[0186] The memory stores executable codes, and when the executable codes are processed by the processor, the processor can execute part or all of the methods described above.

[0187] Input / output interface, used to realize information input and output.

[0188] The communication interface is used to realize the communication interaction between this device and other devices. Communication can be achieved through wired methods (such as USB, network cable, etc.) or wireless methods (such as mobile network, WIFI, Bluetooth, etc.).

[0189] The bus, which transfers information between the various components of the device (such as the processor, memory, input / output interfaces, and communication interfaces);

[0190] The processor, memory, input / output interface and communication interface are connected to each other through a bus inside the device.

[0191] On the other hand, an embodiment of the present invention further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above method.

[0192] It can be understood that the contents of the above method embodiments are all applicable to the present storage medium embodiments, the functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0193] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0194] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0195] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0196] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0197] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0198] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0199] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0200] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0201] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0202] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0203] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including multiple instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), disk or optical disk and other media that can store programs.

[0204] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0205] In the above description of this specification, the description with reference to the terms "one embodiment / example", "another embodiment / example" or "certain embodiments / 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 invention. In this specification, the schematic representation of the above terms does 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.

[0206] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0207] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A method for online estimation of stator flux of a permanent magnet synchronous motor, characterized in that: The method comprises the following steps: Get the speed information of the permanent magnet synchronous motor; Selecting corresponding correction parameters according to the speed information; Obtaining an online estimated stator flux axis component according to the speed information and the correction parameter; A stator flux estimation value is obtained according to the stator flux axial component.

2. The method according to claim 1, characterized in that The step of obtaining the speed information of the permanent magnet synchronous motor comprises the following steps: Set the speed threshold; According to the speed threshold, a speed range is obtained; According to the rotation speed range, rotation speed information is obtained.

3. The method according to claim 1, characterized in that According to the size of the speed information, the corresponding correction parameter is selected, and the formula used includes: Among them, α1 is the first speed threshold; α2 is the second speed threshold; ω r is the angular velocity of the motor; g(ω r ) is the correction parameter with the motor speed as the independent variable.

4. The method according to claim 1, characterized in that: The formula used to obtain the online estimated stator flux axis component according to the speed information and the correction parameter includes: is the α-axis component of the stator flux estimated online by the current model; is the stator flux β-axis component estimated online by the current model; It is the stator flux α-axis component estimated online by the improved voltage model; It is the stator flux β-axis component estimated online by the improved voltage model; ψ sα It is the stator flux α-axis component output by the estimation model; ψ sβ It is the stator flux β-axis component output by the estimated model.

5. The method according to claim 4, characterized in that The equations used in the current model include: in, is the current model in the two-phase stationary coordinate system; θ is the rotation angle of the motor rotor; L d is the inductance of the d-axis in the rotating coordinate system; i d is the current of the d-axis in the rotating coordinate system; is the magnetic flux of the rotor permanent magnet; L q is the inductance of the q-axis in the rotating coordinate system; i q is the current along the q axis in the rotating coordinate system.

6. The method according to claim 1, characterized in that The method for online estimating stator flux of a permanent magnet synchronous motor further comprises the following steps: Set the high-pass filter; According to the high-pass filter and the integrator, a transfer function is obtained; According to the transfer function, an improved voltage model is obtained.

7. The method according to claim 6, characterized in that The transfer function is obtained according to the high-pass filter and the integrator, and the formula used includes: in, is the transfer function; ω c is the cut-off angular frequency of the integrator; E s (s) is the back electromotive force of the motor; s is the complex frequency domain variable in the Laplace transform.

8. A permanent magnet synchronous motor stator flux online estimation system, characterized in that: The system comprises: The first module is used to obtain the speed information of the permanent magnet synchronous motor; The second module is used to select a corresponding correction parameter according to the speed information; A third module is used to obtain an online estimated stator flux axis component according to the speed information and the correction parameter; The fourth module is used to obtain a stator flux estimation value according to the stator flux axis component.

9. A device for online estimation of the stator flux of a permanent magnet synchronous motor, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for online estimation of the stator flux of a permanent magnet synchronous motor as claimed in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the method according to any one of claims 1 to 7.

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