Flux linkage control method, garden tool, electronic device, and storage medium

Abstract

The present invention relates to a flux linkage control method applied to a motor, a garden tool, an electronic device, and a storage medium. The flux linkage control method comprises: determining whether a motor operates; if the motor operates, introducing a flux linkage observer to observe the angle of a rotor, and introducing a parameter identification formula to identify parameters, so as to acquire the latest identified resistance Rs and identified stator inductance Ls that are identified by the parameter identification formula; the flux linkage observer obtaining an observation angle on the basis of the latest identified resistance Rs and identified stator inductance Ls; introducing I / F forced startup, operating at a preset forced startup angle on the basis of a forced startup current, and calculating an absolute value θ of the angle difference between the observation angle and the forced startup angle; comparing θ with a preset threshold; if θ is not greater than the preset threshold, entering closed-loop control and ending the I / F forced startup; and if θ is greater than the preset threshold, continuing to perform the I / F forced startup. Parameter identification is performed while forced startup is performed, so that the observation angle of the observer is more accurate, higher stability is achieved in sensorless operation, and the system robustness is higher.

Description

Magnetic chain control method, garden tool, electronic device and storage medium Technical Field

[0001] The present invention relates to the field of motor control, and more particularly to a magnetic flux control method, a garden tool, an electronic device, and a storage medium applying the magnetic flux control method. Background Art

[0002] Compared to square wave control, FOC sine wave control has the advantages of low noise, smooth operation, low current harmonics, energy saving, small impact peak current on the switching tube, and higher output torque under the same current. Therefore, the electronic control method of garden tools on the market is gradually transitioning from square wave control to sine wave control. In addition, the application of sine wave control can obtain different control solutions according to product requirements:

[0003] (1) For tools such as fans that do not require high starting requirements, speed control or power control can be used as needed. Compared with square waves, the overshoot is small, the operation is stable, and the efficiency is high. The sine wave motor theory using weak magnetic control can obtain a higher limit speed, further improving system performance.

[0004] (2) For tools that require heavy-load starting, such as chain saws and lawn mowers, direct torque control can be used. Its dynamic response speed is high and it can quickly reach the target output. It is very suitable for starting on steep slopes, cutting heavy objects, and other occasions that require high torque starting.

[0005] Permanent magnet motor drive control schemes generally employ dual closed-loop detection, with rotor position and speed detection being essential. Adding sensors to the motor system increases system size and cost, reducing reliability. Consequently, sensorless field-of-control (FOC) control has become a major development direction for motor control. Currently, state observers are commonly used as sensorless control algorithms and can be categorized as flux observers and back-EMF observers. Both are angle-based observation schemes based on the motor voltage equation and assume constant motor parameters during computation.

[0006] Traditional sensorless control algorithms based on the motor voltage equation offer advantages such as simplicity, rapid convergence, and low steady-state error when the model is constant. However, motor parameters are affected by operating conditions and the operating environment. Permanent magnet synchronous motors have high output power, large current amplitudes and harmonics, and their temperatures rise continuously during operation. The stator resistance of the motor is prone to fluctuations. If magnetic circuit saturation occurs during operation, the inductance amplitude and flux linkage will also change. These issues can reduce the recognition capability of sensorless control algorithms.

[0007] Assuming a motor resistance of 1 ohm at room temperature (25°C), the curve of motor resistance versus temperature is roughly as shown in Figure 1. As shown in Figure 1, the resistance of copper wire increases approximately linearly with increasing temperature. When motors used in garden tools such as chainsaws and fans operate at temperatures exceeding 120°C for extended periods, their resistance increases by approximately 20%, significantly changing the original parameter model. However, when the motor operates in the heavy-load saturation range, the flux linkage and inductance increase exponentially, making them difficult to quantify using curve fitting. This can directly lead to abnormal motor operation. Abnormal operation of high-speed motors used in garden tools can often have dangerous consequences. Summary of the Invention

[0008] In order to solve at least one of the technical problems raised above, the present application provides a magnetic flux control method, which performs parameter identification simultaneously with forced drag, and the parameters of the two are complementary, which can make the observer's observation angle more accurate, more stable after entering the sensorless operation, and more robust the system.

[0009] The present application provides a flux control method applied to a motor, comprising:

[0010] If the motor is detected to be running, the motor operating parameters are collected, where the motor operating parameters include resistance, and / or inductance, and / or electromagnetic;

[0011] Processing the motor operating parameters according to the parameter processing model to obtain first detection data;

[0012] Processing the motor operating parameters according to the I / F control method to obtain second detection data;

[0013] If the difference between the first detection data and the second detection data is less than a preset threshold, continue to process the motor operating parameters through the parameter processing model;

[0014] Otherwise, the parameter processing model is modified.

[0015] Preferably, the present application provides a parameter processing model for a flux control method for a motor, including:

[0016] The magnetic flux observation model is used, and the motor operating parameters are processed according to the parameter processing model to obtain the first detection data, including:

[0017] Processing the motor operating parameters through a parameter identification formula to obtain identified motor operating parameters, wherein the processed motor operating parameters include: identified resistance, and / or identified inductance, and / or electromagnetic;

[0018] The identified motor operating parameters are processed by a flux observation model to obtain an observation angle, thereby obtaining first detection data.

[0019] Preferably, the present application provides a method for controlling a flux linkage of a motor, wherein the method processes the motor operating parameters according to an I / F control method to obtain second detection data, including:

[0020] Based on the forced drag start of the I / F system, a preset forced drag angle of the motor under a preset forced drag current is obtained, thereby obtaining second detection data.

[0021] Preferably, the present application provides a method for obtaining identified motor operating parameters in a flux control method for a motor, comprising:

[0022] Collect real-time voltage U d 、U q , real-time quadrature axis current I q , real-time direct-axis current I d ;

[0023] The parameter identification formula is introduced to use the real-time voltage U collected d 、U q , the real-time quadrature-axis current I q , the real-time direct-axis current I d The identification resistance R obtained in the previous round s , the identification of stator inductance L s Make corrections and define the difference between the identified value and the actual value as the generalized error of the identification system;

[0024] When the sum of squares of the generalized errors is at a minimum, the identification is successful, and the new identification resistance R is obtained. s , the identification of stator inductance L s .

[0025] Preferably, the present application provides a method for controlling the flux linkage of a motor, wherein the parameter identification formula is a forgetting factor recursive least squares method, and the mathematical model of the forgetting factor recursive least squares method is:

[0026] Among them, θ is the current parameter, θ(k-1) is the parameter to be identified, K(k) is the gain matrix, is the observation matrix, P(k-1) is the covariance matrix, y(k) is the output parameter, P(K) is the current covariance matrix, λ is the forgetting factor,

[0027] λ usually takes a value in the range of 0.9 to 1, and the gain matrix K(k) and the covariance matrix P(k-1) are given values.

[0028] Preferably, the present application provides a flux observation model in a flux control method for a motor, including a nonlinear flux observer. The mathematical model of the nonlinear flux observer is:

[0029] The rotor flux is obtained by subtracting the stator flux from the total flux: ψ rotor =∫(U αβ -I αβ R S )dt-L S I αβ

[0030] Among them, ψ rotor is the component matrix of the rotor flux on the α-axis and β-axis, U αβ is the component matrix of voltage on the α-axis and β-axis, I αβ is the component matrix of the current on the α-axis and β-axis, R s is the internal resistance of the motor, L s is the motor inductance;

[0031] Perform error correction on the rotor flux:

[0032] Where U is the component matrix of voltage on the α-axis and β-axis, I is the component matrix of current on the α-axis and β-axis, R is the motor internal resistance, γ is the correction parameter, and ψ is the real-time flux determined by the identification parameters;

[0033] is the observed flux, and θ is the motor angle, which can be estimated by PLL or arc tangent.

[0034] Preferably, the present application provides a flux control method for a motor, which further includes, before processing the motor operating parameters through a parameter identification formula:

[0035] The flux observer obtains the observed angle and flux according to the rated parameters of the motor, and identifies the rated parameters of the motor through the parameter identification formula to obtain the latest identification resistance R s , the identification of stator inductance L s And bring it into the magnetic flux observation model.

[0036] Preferably, the present application provides a flux control method for a motor. After closed-loop control, the mathematical model of the voltage equation is:

[0037] Among them, u d (k),u q (k) is the d and q axis voltage, i d (k、i q (k) is the d and q axis current, ω e (k) is the rotation speed, T s is the time constant, To identify the real-time resistance, Real-time inductance for identification.

[0038] Preferably, the present application provides a flux control method for a motor, further comprising a flux observer dynamic update method, including:

[0039] Acquire pre-stored motor parameters of the motor, wherein the motor parameters include pre-stored flux linkage, pre-stored resistance, and pre-stored inductance;

[0040] Obtain the flux value observed by the flux observer, calculate the absolute value of the difference between the observed flux value and the pre-stored flux value,

[0041] If the absolute value of the difference is not greater than the preset threshold, the magnetic flux observation model is accurate and the observation is continued using the magnetic flux observation model;

[0042] If the absolute value of the difference is greater than the preset threshold, the flux linkage observation model is inaccurate, and the parameter identification formula is used for iterative calculation to set the new identification resistance R s , the identification of stator inductance L s Substitute it into the flux observer to perform update calculation until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold value, and use the latest identification resistor R s , the identification of stator inductance L s , and update the pre-stored motor parameters with the observed flux linkage values.

[0043] Preferably, the present application provides a flux control method for a motor, further comprising a flux observer dynamic update method, including:

[0044] If the absolute value of the difference is greater than the preset threshold, the flux linkage observation model is inaccurate, and the parameter identification formula is used for iterative calculation to set the new identification resistance R s , the identification of stator inductance L s Substitute it into the flux observer to perform update calculation until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold value, and use the latest identification resistor R s , the identification of stator inductance L s , and update the pre-stored motor parameters with the observed flux linkage values.

[0045] The present application also provides a garden tool, comprising a motor and a control unit connected to the motor, wherein the control unit controls the motor according to the above-mentioned flux control method;

[0046] Wherein, the control unit is used for:

[0047] If the motor is detected to be running, the motor operating parameters are collected, where the motor operating parameters include resistance, and / or inductance, and / or electromagnetic;

[0048] Processing the motor operating parameters according to the parameter processing model to obtain first detection data;

[0049] Processing the motor operating parameters according to the I / F control method to obtain second detection data;

[0050] If the difference between the first detection data and the second detection data is less than a preset threshold, continue to process the motor operating parameters through the parameter processing model;

[0051] Otherwise, the parameter processing model is modified.

[0052] Preferably, the present application provides a garden tool, wherein the parameter processing model in the control unit of the garden tool includes: a magnetic flux observation model, and the processing of the motor operating parameters according to the parameter processing model to obtain the first detection data includes:

[0053] Processing the motor operating parameters through a parameter identification formula to obtain identified motor operating parameters, wherein the processed motor operating parameters include: identified resistance, and / or identified inductance, and / or electromagnetic;

[0054] The identified motor operating parameters are processed by a flux observation model to obtain an observation angle, thereby obtaining first detection data.

[0055] Preferably, the present application provides a garden tool, wherein the control unit in the garden tool is further used for:

[0056] Based on the forced drag start of the I / F system, a preset forced drag angle of the motor under a preset forced drag current is obtained, thereby obtaining second detection data.

[0057] Preferably, the present application provides a garden tool, wherein the control unit in the garden tool is further configured to: after comparing θ with a preset threshold, if θ is greater than the preset threshold, continue to perform I / F forced drag. Preferably, the present application provides a garden tool, wherein the control unit in the garden tool is further configured to:

[0058] Collect real-time voltage U d 、U q , real-time quadrature axis current I q , real-time direct-axis current I d ;

[0059] The parameter identification formula is introduced to use the real-time voltage U collected d 、U q , the real-time quadrature-axis current I q , the real-time direct-axis current I d The identification resistance R obtained in the previous round s , the identification of stator inductance L sMake corrections and define the difference between the identified value and the actual value as the generalized error of the identification system;

[0060] When the sum of squares of the generalized errors is at a minimum, the identification is successful, and the new identification resistance R is obtained. s , the identification of stator inductance L s .

[0061] Among them, the real-time voltage U d and voltage U q ,include:

[0062] Voltage U q : Represents the q-axis component of the voltage, that is, the voltage related to the quadrature axis (q-axis) direction of the motor.

[0063] Voltage U d : Represents the d-axis component of the voltage, that is, the voltage related to the motor's direct axis (d-axis) direction.

[0064] Voltage U d and voltage U q Together they describe the voltage state of the motor in the dq coordinate system and are important parameters that are indispensable in motor control.

[0065] Among them, the real-time quadrature axis current I q , real-time direct-axis current I d ,include:

[0066] I q : Represents the quadrature-axis current, that is, the current flowing in the quadrature-axis (q-axis) direction of the motor.

[0067] I d : Represents the direct axis current, that is, the current flowing in the direction of the motor's direct axis (d axis).

[0068] Real-time quadrature axis current I q , real-time direct-axis current I d Together they determine the motor's electromagnetic torque, magnetic flux and other performance.

[0069] By adjusting the real-time quadrature-axis current I q , real-time direct-axis current I d The ratio of the output torque and efficiency of the motor can be accurately controlled.

[0070] When I q = 0, the motor mainly generates magnetic resistance torque; when I d = 0, the motor mainly generates permanent magnet torque. By adjusting I q and I d The value of can achieve optimal control of the motor under different working conditions.

[0071] Preferably, the present application provides a garden tool, wherein the parameter identification formula in the control unit of the garden tool includes: a forgetting factor recursive least squares method, and the mathematical model of the forgetting factor recursive least squares method is:

[0072] Among them, θ is the current parameter, θ(k-1) is the parameter to be identified, K(k) is the gain matrix, is the observation matrix, P(k-1) is the covariance matrix, y(k) is the output parameter, P(K) is the current covariance matrix, λ is the forgetting factor,

[0073] λ usually takes a value in the range of 0.9 to 1, and the gain matrix K(k) and the covariance matrix P(k-1) are given values.

[0074] Preferably, the present application provides a garden tool, wherein the flux observer in the control unit of the garden tool is a nonlinear flux observer, and the mathematical model of the nonlinear flux observer is:

[0075] The rotor flux is obtained by subtracting the stator flux from the total flux: ψ rotor =∫(U αβ -I αβ R S )dt-L S I αβ

[0076] Among them, ψ rotor is the component matrix of the rotor flux on the α-axis and β-axis, U αβ is the component matrix of voltage on the α-axis and β-axis, I αβ is the component matrix of the current on the α-axis and β-axis, R s is the internal resistance of the motor, L s is the motor inductance;

[0077] Perform error correction on the rotor flux:

[0078] Where U is the component matrix of voltage on the α-axis and β-axis, I is the component matrix of current on the α-axis and β-axis, R is the motor internal resistance, γ is the correction parameter, and ψ is the real-time flux determined by the identification parameters;

[0079] is the observed flux, and θ is the motor angle, which can be estimated by PLL or arc tangent.

[0080] Preferably, the present application provides a garden tool, wherein the control unit in the garden tool is configured to identify the resistance R according to the latest s , the identification of stator inductance L s , before obtaining the observation angle, is also used to:

[0081] The flux observer obtains the observed angle and flux according to the rated parameters of the motor, and identifies the rated parameters of the motor through the parameter identification formula to obtain the latest identification resistance R s , the identification of stator inductance L s And bring it into the magnetic flux observation model.

[0082] Preferably, the present application provides a garden tool, wherein the control unit in the garden tool has a voltage equation whose mathematical model is:

[0083] Among them, u d (k),u q (k) is the d and q axis voltage, i d (k), i q (k) is the d and q axis current, ω e (k) is the rotation speed, T s is the time constant, To identify the real-time resistance, Real-time inductance for identification.

[0084] Preferably, the present application provides a garden tool, wherein the control unit in the garden tool is further used in a method for dynamically updating a magnetic flux observer, wherein the method for dynamically updating a magnetic flux observer includes:

[0085] Acquire pre-stored motor parameters of the motor, wherein the motor parameters include pre-stored flux linkage, pre-stored resistance, and pre-stored inductance;

[0086] Obtain the flux value observed by the flux observer, calculate the absolute value of the difference between the observed flux value and the pre-stored flux value,

[0087] If the absolute value of the difference is not greater than the preset threshold, the magnetic flux observation model is accurate and the observation is continued using the magnetic flux observation model;

[0088] If the absolute value of the difference is greater than the preset threshold, the flux linkage observation model is inaccurate, and the parameter identification formula is used for iterative calculation to set the new identification resistance R s , the identification of stator inductance L s Substitute it into the flux observer to perform update calculation until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold value, and use the latest identification resistor R s , the identification of stator inductance L s , and update the pre-stored motor parameters with the observed flux linkage values.

[0089] The present application also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned flux control method when executing the computer program.

[0090] The present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and is characterized in that when the computer program is executed by a processor, the above-mentioned magnetic flux control method is implemented.

[0091] The flux control method for the motor provided in this application is to observe the flux during the I / F strong drag period according to the latest identification resistance R s , Identify stator inductance L s , the observation angle and magnetic flux are obtained, the results are more accurate, the subsequent switching into sensorless operation is more stable, and the control system is more robust. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] FIG1 is a schematic diagram of a curve showing changes in motor resistance with temperature in the prior art;

[0093] FIG2 is a flow chart of the flux control method provided by the present application;

[0094] FIG3 is a flow chart of the flux control method provided by the present application;

[0095] FIG4 is a flow chart of a dynamic update method for a flux observer provided by the present application;

[0096] FIG5 is a flow chart of a motor control system provided by the present application;

[0097] FIG6 is a simulation curve diagram of the observed value and actual value of the flux observer algorithm provided in this application. DETAILED DESCRIPTION

[0098] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. For example, terms such as "upper," "lower," "front," and "rear" indicating orientation or positional relationships are based solely on the orientation or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the disclosure. They do not indicate or imply that the device or element referred to must have a specific orientation or be constructed or operated in a specific orientation. Therefore, they should not be construed as limiting the disclosure.

[0099] The present application discloses a gardening tool comprising a motor and a control unit connected to the motor, wherein the control unit controls the motor according to a magnetic flux control method. The gardening tool may be a hair dryer, a chain saw, or the like.

[0100] Specifically, as shown in FIG2 , the flux control method includes steps 201 to 204:

[0101] Step 201: If the motor is detected to be running, collect the motor operating parameters, which include resistance, and / or inductance, and / or electromagnetic;

[0102] Step 202: Process the motor operating parameters according to the parameter processing model to obtain first detection data;

[0103] Step 203: Process the motor operating parameters according to the I / F control method to obtain second detection data;

[0104] Step 204: If the difference between the first detection data and the second detection data is less than a preset threshold, continue to process the motor operating parameters using the parameter processing model;

[0105] Otherwise, the parameter processing model is modified.

[0106] The aforementioned I / F control is used to set the appropriate current-frequency ratio for the inverter based on the permanent magnet synchronous motor's load characteristics, matching the motor's output torque to the load at different speeds for high operating efficiency. The I / F control strategy operates in an open-loop speed and closed-loop current state. A PI regulator forms the closed-loop current loop in the DQ axis coordinate system. Current feedback is constrained to the desired value to prevent overcurrent.

[0107] In an optional embodiment, the parameter processing model in the method provided in the present application includes: a flux observation model, and the above step 202 processes the motor operating parameters according to the parameter processing model to obtain the first detection data, including:

[0108] Processing the motor operating parameters through a parameter identification formula to obtain identified motor operating parameters, wherein the processed motor operating parameters include: identified resistance, and / or identified inductance, and / or electromagnetic;

[0109] The identified motor operating parameters are processed by a flux observation model to obtain an observation angle, thereby obtaining first detection data.

[0110] The flux observation model is an algorithm used for motor control. It estimates the internal flux of the motor by analyzing the voltage and current signals on the stator side in real time, thereby determining the rotor position and speed. While the flux observer can achieve sensorless control, it is important to observe the phase and amplitude of the rotor flux to avoid system oscillation or instability.

[0111] In an optional embodiment, the step 203 of the flux control method provided in the present application of processing the motor operating parameters according to the I / F control mode to obtain the second detection data includes:

[0112] Based on the forced drag start of the I / F system, a preset forced drag angle of the motor under a preset forced drag current is obtained, thereby obtaining second detection data.

[0113] Open-loop forced drag in I / F control refers to the speed loop being open, while the current loop remains in closed-loop control. During this process, the IF control module is required to provide two quantities: the Q-axis current and the open-loop angular velocity. The open-loop electrical angle is obtained by integrating the angular velocity provided by the IF module. In an optional embodiment, please refer to the flowchart shown in Figure 3. The flux control method provided in this application may also include the following steps:

[0114] Determine whether the motor is running. If the motor is running, introduce the flux observer to observe the angle, and introduce the parameter identification formula to identify the parameters.

[0115] Get the latest identification resistance R after the parameter identification formula is identified s , Identify stator inductance L s , the flux observer is based on the latest identification resistor R s , Identify stator inductance L s , and obtain the observation angle;

[0116] Introducing I / F control, based on the strong drag current and running at the preset strong drag angle, calculates the absolute value θ of the angle difference between the observed angle and the preset strong drag angle;

[0117] Compare the value of θ with the preset threshold. If θ is not greater than the preset threshold, enter closed-loop control and end I / F forced drag.

[0118] If it is greater than the preset threshold, the I / F forced dragging will continue.

[0119] The flux control method is based on the latest identification resistor R s , Identify stator inductance L s , before obtaining the observation angle, it also includes:

[0120] The flux observer obtains the observed angle and flux according to the rated parameters of the motor, and identifies the rated parameters of the motor through the parameter identification formula to obtain the latest identification resistance R s , Identify stator inductance L s And bring it into the magnetic flux observation model.

[0121] In addition, after closed-loop control, the mathematical model of the voltage equation is:

[0122] Among them, u d (k),u q (k) is the d and q axis voltage, i d (k), i q (k) is the d and q axis current, ω e(k) is the rotation speed, T s is the time constant, To identify the real-time resistance, Real-time inductance for identification.

[0123] The flux observer of this application is a nonlinear observer. The mathematical model of the linear observer is:

[0124] The rotor flux is obtained by subtracting the stator flux from the total flux: ψ rotor =∫(U αβ -I αβ R S )dt-L S I αβ

[0125] Among them, ψ rotor is the component matrix of the rotor flux on the α-axis and β-axis, U αβ is the component matrix of voltage on the α-axis and β-axis, I αβ is the component matrix of the current on the α-axis and β-axis, R s is the internal resistance of the motor, L s is the motor inductance;

[0126] Perform error correction on the rotor flux:

[0127] Where U is the voltage component matrix on the α-axis and β-axis, I is the current component matrix on the α-axis and β-axis, R is the motor internal resistance, γ is the correction parameter, and ψ is the real magnetic flux determined by the identification parameters.

[0128] is the observed flux, and θ is the motor angle, which can be estimated by PLL or arc tangent.

[0129] In order to verify the feasibility of the flux observer algorithm, the above observer algorithm was built on MATLAB-Simulink, and the curve simulation diagram shown in Figure 5 was obtained.

[0130] The calculated rotor flux quickly converges to the actual motor flux. Therefore, after the motor passes the high-powered drag period, the voltage equation mathematical model within the closed-loop algorithm uses the motor's dynamic flux data. This prevents system instability due to nonlinear flux drift under high temperature and heavy load conditions. The rotor motor angle information quickly and accurately tracks the actual motor angle, achieving angle convergence before the end of the high-powered drag period, ensuring reliable closed-loop operation.

[0131] During the I / F strong drag period, the flux observation of this application is based on the latest identification resistance R s , Identify stator inductance L s, the observation angle and magnetic flux are obtained, the results are more accurate, the subsequent switching into sensorless operation is more stable, and the control system is more robust.

[0132] This application obtains the identification resistance R s , Identify stator inductance L s The methods include:

[0133] Collect real-time voltage U d 、U q , real-time quadrature axis current I q , real-time direct-axis current I d ;

[0134] The parameter identification formula is introduced to use the collected real-time voltage U d 、U q , real-time quadrature axis current I q , real-time direct-axis current I d The identification resistance R obtained in the previous round s , Identify stator inductance L s Correction is performed, and the difference between the identified value and the actual value is defined as the generalized error of the identification system. When the sum of the squares of the generalized errors is at the minimum, the identification is successful, and the new identification resistance R is obtained. s , Identify stator inductance L s .

[0135] The parameter identification formula is the forgetting factor recursive least squares method, and the mathematical model of the forgetting factor recursive least squares method is:

[0136] Among them, θ is the current parameter, θ(k-1) is the parameter to be identified, K(k) is the gain matrix, is the observation matrix, P(k-1) is the covariance matrix, y(k) is the output parameter, P(K) is the current covariance matrix, λ is the forgetting factor,

[0137] λ usually ranges from 0.9 to 1, and the gain matrix K(k) and covariance matrix P(k-1) are given values.

[0138] The magnetic observer algorithm in this application enables online adjustment of the amplitudes of parameters such as resistance and inductance, thereby improving algorithm stability. An additional magnetic observer algorithm is used to identify two other electrical parameters, resistance and inductance. Ultimately, all identified unknown parameters are fed back to the system for more precise control performance. This allows for significant parameter changes during motor heating and heavy load saturation conditions, resulting in more stable system control.

[0139] In addition, since the permanent magnets of the motor are easily demagnetized due to factors such as temperature and heavy load overcurrent, and dynamic motor-related parameters are required, a dynamic update method of the flux observer is also disclosed, as shown in Figure 3, including:

[0140] Obtain the motor's pre-stored parameters, including pre-stored flux, pre-stored resistance, and pre-stored inductance. The initial flux can be the value measured by the motor supplier under a certain temperature environment.

[0141] Obtain the flux value observed by the flux observer, calculate the absolute value of the difference between the observed flux value and the pre-stored flux value,

[0142] If the absolute value of the difference is not greater than the preset threshold, the magnetic flux observation model is accurate and the observation is continued using the magnetic flux observation model;

[0143] If the absolute value of the difference is greater than the preset threshold, the flux linkage observation model is inaccurate, and the parameter identification formula is used for iterative calculation to set the new identification resistance R s , Identify stator inductance L s Substitute it into the flux observer for update calculation until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold, that is, the new identification resistance R obtained after the parameter identification iteration is stable s , Identify stator inductance L s After being substituted into the flux observer, the flux observer calculates the new flux and cycles until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold. s , Identify stator inductance L s , and update the pre-stored motor parameters with the observed flux linkage values.

[0144] The present application also discloses an electronic device, which includes a memory, a processor, and a computer program stored in the memory and runable on the processor, and the processor executes the computer program to implement the above-mentioned magnetic flux control method. The electronic device is a computing device such as a server, a desktop computer, a tablet computer, a cloud server, and a mobile terminal. The memory is a hard disk or internal memory in the electronic device, or a USB flash drive, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, or a flash card (FlashCard) plugged into the electronic device. The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc.

[0145] The present application also discloses a computer-readable storage medium storing a computer program that implements the aforementioned flux control method when executed by a processor. The computer program includes computer program code, which may be in source code form, object code form, an executable file, or some intermediate form. The computer-readable medium may include any entity or device capable of carrying computer program code, a recording medium, a USB flash drive, a mobile hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunications signal, and a software distribution medium.

[0146] As can be seen from the above, the flux control method disclosed in this application, the flux observation during the I / F strong pull period is based on the latest identification resistance R s , Identify stator inductance L s , the observation angle and magnetic flux are obtained, the results are more accurate, the subsequent switching into sensorless operation is more stable, and the control system is more robust.

[0147] The present invention is not limited to the specific embodiments described above. Those skilled in the art will readily appreciate that many alternatives to the outer rotor motor of the present invention exist without departing from the principles and scope of the present invention. The scope of protection of the present invention shall be determined by the claims.

Claims

1. A flux control method for a motor, characterized by: include: If the motor is detected to be running, the motor operating parameters are collected, where the motor operating parameters include resistance, and / or inductance, and / or electromagnetic; Processing the motor operating parameters according to the parameter processing model to obtain first detection data; Processing the motor operating parameters according to the I / F control method to obtain second detection data; If the difference between the first detection data and the second detection data is less than a preset threshold, continue to process the motor operating parameters through the parameter processing model; Otherwise, the parameter processing model is modified.

2. The flux control method according to claim 1, wherein: The parameter processing model includes a flux observation model, and the step of processing the motor operating parameters according to the parameter processing model to obtain first detection data includes: Processing the motor operating parameters through a parameter identification formula to obtain identified motor operating parameters, wherein the processed motor operating parameters include: identified resistance, and / or identified inductance, and / or electromagnetic; The identified motor operating parameters are processed by a flux observation model to obtain an observation angle, thereby obtaining first detection data.

3. The flux control method according to claim 2, wherein: Processing the motor operating parameters according to the I / F control method to obtain second detection data includes: Based on the forced drag start of the I / F system, a preset forced drag angle of the motor under a preset forced drag current is obtained, thereby obtaining second detection data.

4. The flux control method according to claim 2, wherein: Obtain the identified motor operating parameters, including: Collect real-time voltage U d 、U q , real-time quadrature axis current I q , real-time direct-axis current I d ; The parameter identification formula is introduced to use the real-time voltage U collected d 、U q , the real-time quadrature-axis current I q , the real-time direct-axis current I d The identification resistance R obtained in the previous round s , the identification of stator inductance L s Make corrections and define the difference between the identified value and the actual value as the generalized error of the identification system; When the sum of squares of the generalized errors is at a minimum, the identification is successful, and the new identification resistance R is obtained. s , the identification of stator inductance L s .

5. The flux control method according to claim 2, wherein: The parameter identification formula is the forgetting factor recursive least squares method, and the mathematical model of the forgetting factor recursive least squares method is: Among them, θ is the current parameter, θ(k-1) is the parameter to be identified, K(k) is the gain matrix, is the observation matrix, P(k-1) is the covariance matrix, y(k) is the output parameter, P(K) is the current covariance matrix, λ is the forgetting factor, λ usually takes a value in the range of 0.9 to 1, and the gain matrix K(k) and the covariance matrix P(k-1) are given values.

6. The flux control method according to claim 2, wherein: The flux observation model includes a nonlinear flux observer, and the mathematical model of the nonlinear flux observer is: The rotor flux is obtained by subtracting the stator flux from the total flux: ψ rotor =∫(U αβ -I αβ R S )dt-L S I αβ Among them, ψ rotor is the component matrix of the rotor flux on the α-axis and β-axis, U αβ is the component matrix of voltage on the α-axis and β-axis, I αβ is the component matrix of the current on the α-axis and β-axis, R s is the internal resistance of the motor, L s is the motor inductance; Perform error correction on the rotor flux: Where U is the component matrix of voltage on the α-axis and β-axis, I is the component matrix of current on the α-axis and β-axis, R is the motor internal resistance, γ is the correction parameter, and ψ is the real-time flux determined by the identification parameters; is the observed flux, and θ is the motor angle, which can be estimated by PLL or arc tangent.

7. The flux control method according to claim 1, wherein: Before processing the motor operating parameters through the parameter identification formula, the flux control method further includes: The flux observer obtains the observed angle and flux according to the rated parameters of the motor, and identifies the rated parameters of the motor through the parameter identification formula to obtain the latest identification resistance R s , the identification of stator inductance L s And bring it into the magnetic flux observation model.

8. The flux control method according to claim 1, wherein: After closed-loop control, the mathematical model of the voltage equation is: Among them, u d (k),u q (k) is the d and q axis voltage, i d (k), i q (k) is the d and q axis current, ω e (k) is the rotation speed, T s is the time constant, To identify the real-time resistance, Real-time inductance for identification.

9. The flux control method according to claim 1, wherein: The flux control method further includes modifying the parameter processing model, including: Acquiring pre-stored motor parameters of the motor, wherein the pre-stored motor parameters include pre-stored flux linkage, pre-stored resistance, and pre-stored inductance; Obtain the flux value observed by the flux observer, calculate the absolute value of the difference between the observed flux value and the pre-stored flux value, If the absolute value of the difference is not greater than the preset threshold, the magnetic flux observation model is accurate and the observation is continued using the magnetic flux observation model; If the absolute value of the difference is greater than the preset threshold, the flux linkage observation model is inaccurate, and the parameter identification formula is used for iterative calculation to set the new identification resistance R s , the identification of stator inductance L s Substitute it into the flux observer to perform update calculation until the absolute value of the difference between the observed flux value and the pre-stored flux value is no greater than the preset threshold value, and use the latest identification resistor R s , the identification of stator inductance L s , and update the pre-stored motor parameters with the observed flux linkage values.

10. A garden tool comprising a motor and a control unit connected to the motor, wherein the control unit controls the motor according to the flux control method according to any one of claims 1 to 9.

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