Method for adjusting time constant of rotor of asynchronous motor, current correction method, device and system

Abstract

The application provides a method and device for adjusting the time constant of an asynchronous motor rotor, and a current correction method, device and system, and relates to the technical field of motor control. The method comprises the following steps: obtaining the rotor electric angular velocity, resistance and inductance; obtaining the three-phase current and three-phase voltage of the motor; using a current model to calculate a first torque according to the rotor d-axis flux, rotor q-axis flux, initial rotor time constant, stator d-axis current and stator q-axis current; using a voltage model to calculate a second torque according to the stator alpha-axis flux, stator beta-axis flux, stator alpha-axis voltage, stator beta-axis voltage, stator alpha-axis current and stator beta-axis current; making the deviation of the first torque relative to the second torque within a preset range to generate a rotor time constant compensation value; and compensating the initial rotor time constant. The application solves the problem of poor torque control accuracy of the asynchronous motor caused by the calculation of the rotor time constant based on the offline measured rotor inductance and resistance for controlling the stator d-axis current and stator q-axis current.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method for adjusting the rotor time constant of an asynchronous motor, a current correction method, a device, and a system. Background Technology

[0002] In asynchronous motor rotor flux orientation control, accurate rotor time constants are essential for proper decomposition of d / q axis currents. However, in practical applications, the rotor time constant is often calculated from offline measurements of inductance and resistance. When the rotor temperature rises, both rotor resistance and inductance change. In this case, the calculated rotor time constant will deviate from the actual accurate value. If the rotor time constant is still calculated from offline measurements of resistance and inductance, the d / q axis currents will not be accurately decomposed, directly affecting the torque control accuracy of the asynchronous motor and potentially causing problems such as voltage saturation in the field weakening zone. Summary of the Invention

[0003] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method for adjusting the rotor time constant of an asynchronous motor, a current correction method, a device and a system, to solve the problem that the existing method of calculating the rotor time constant based on offline measured rotor inductance and resistance to control the d-axis current and q-axis current results in poor torque control accuracy of the asynchronous motor.

[0004] This invention discloses a method for adjusting the rotor time constant of an asynchronous motor, comprising:

[0005] Obtain the rotor electrical angular velocity, resistance, and inductance of the motor, and calculate the initial rotor time constant based on the resistance and inductance;

[0006] The three-phase current and three-phase voltage of the motor are obtained, and the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current are obtained based on the initial rotor time constant, the three-phase current, and the three-phase voltage.

[0007] The rotor d-axis flux linkage and rotor q-axis flux linkage are obtained using a current model based on the rotor electric angular velocity. The first torque is then calculated based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current.

[0008] The stator α-axis flux linkage and stator β-axis flux linkage are obtained using a voltage model. The second torque is calculated based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current.

[0009] The rotor time constant is adjusted based on the initial rotor time constant so that the deviation of the first torque relative to the second torque is within a preset range, thereby generating a rotor time constant compensation value.

[0010] The initial rotor time constant is compensated according to the rotor time constant compensation value.

[0011] Preferably, a PI controller is used to adjust the rotor time constant.

[0012] Preferably, the rotor d-axis flux linkage and rotor q-axis flux linkage are obtained using a current model based on the rotor's electric angular velocity, including:

[0013] The current model is expressed as: ;

[0014] in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; The rotor's electric angular velocity; As a variable; , These are the stator d-axis current and stator q-axis current, respectively.

[0015] In the current model, the variables are assigned the rotor electric angular velocity and then subjected to a Laplace transform to calculate the rotor d-axis flux linkage and rotor q-axis flux linkage.

[0016] Preferably, the rotor d-axis flux linkage and rotor q-axis flux linkage are represented as follows: ;

[0017] in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; , These are the stator d-axis current and the stator q-axis current, respectively.

[0018] Preferably, the step of obtaining the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model includes:

[0019] The voltage model is represented as follows: ;

[0020] in, , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and β current, respectively. For rotor resistance; , These are the stator α-axis voltage and the stator β-axis voltage, respectively.

[0021] Preferably, the first torque is expressed as: ;

[0022] The second torque is expressed as: ;

[0023] in, , These represent the first torque and the second torque, respectively; K1 and K2 are preset parameters. , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and stator β-axis current, respectively. , These are the stator d-axis current and the stator q-axis current, respectively.

[0024] The present invention also provides a method for current correction of an asynchronous motor, comprising:

[0025] Collect the three-phase current of the motor;

[0026] Based on the method for adjusting the rotor time constant of an asynchronous motor and the three-phase current, the adjusted rotor time constant is obtained, and the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage are calculated according to the current model.

[0027] The adjusted stator α-axis flux linkage and stator β-axis flux linkage are calculated based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity.

[0028] The rotor flux linkage angle is updated through trigonometric transformation based on the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

[0029] The target d-axis current and target q-axis current are obtained based on the updated rotor flux angle and the three-phase current of the motor.

[0030] Preferably, the step of calculating the adjusted stator α-axis flux linkage and stator β-axis flux linkage based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage, and rotor electrical angular velocity includes:

[0031] Based on the rotor electric angular velocity, the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage are subjected to inverse Park transformation to obtain the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

[0032] The present invention also provides a device for adjusting the rotor time constant of an asynchronous motor, comprising:

[0033] The first acquisition module is used to acquire the rotor electric angular velocity, resistance and inductance of the motor, and calculate the initial rotor time constant based on the resistance and inductance.

[0034] The second acquisition module is used to acquire the three-phase current and three-phase voltage of the motor, and transform the three-phase current and three-phase voltage based on the initial rotor time constant to obtain the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current.

[0035] The first calculation module is used to obtain the rotor d-axis flux linkage and rotor q-axis flux linkage based on the rotor electric angular velocity using a current model, and to calculate the first torque based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current.

[0036] The second calculation module is used to obtain the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model, and to calculate the second torque based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current.

[0037] The processing module is used to adjust the initial rotor time constant using a PI controller so that the deviation of the first torque relative to the second torque is within a preset range, thereby generating a rotor time constant compensation value; and to compensate the initial rotor time constant according to the rotor time constant compensation value.

[0038] The present invention also provides an asynchronous motor current correction system, comprising:

[0039] The pre-control module is used to collect the three-phase current of the motor;

[0040] The adjustment module is used to obtain the adjusted rotor time constant from the adjustment device of the asynchronous motor rotor time constant according to the three-phase current, calculate the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage according to the current model; calculate the adjusted stator α-axis flux linkage and stator β-axis flux linkage according to the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity; and update the rotor flux linkage angle through trigonometric transformation according to the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

[0041] The correction module is used to obtain the target d-axis current and the target q-axis current based on the updated rotor flux linkage angle and the three-phase current.

[0042] Compared with existing technologies, the above technical solution has the following advantages:

[0043] The method, current correction method, device, and system for adjusting the rotor time constant of an asynchronous motor disclosed in this application integrate rotor electric angular velocity, inductance, rotor resistance, stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current. Then, a second torque calculated using the stator flux linkage (stator α-axis flux linkage and stator β-axis flux linkage) is used to adjust the first torque calculated based on the rotor flux linkage (rotor d-axis flux linkage and rotor q-axis flux linkage), thereby adjusting the rotor time constant to match the actual operating scenario. This improves the accuracy of the decomposition of the d / q-axis current calculated based on the rotor time constant, thus enhancing the precision of torque control. Attached Figure Description

[0044] Figure 1 This is a flowchart of an embodiment of the method for adjusting the rotor time constant of the asynchronous motor, the current correction method, the device, and the system method of the present invention;

[0045] Figure 2 This is a flowchart of Embodiment 3 of the method for adjusting the rotor time constant of the asynchronous motor, the current correction method, the device, and the system method according to the present invention;

[0046] Figure 3 These are schematic diagrams of modules in Embodiments 2 and 4 of the apparatus and system method described in this invention.

[0047] Figure label:

[0048] 11-Asynchronous motor current correction system; 111-Pre-control module; 112-Adjustment module; 113-Correction module; 10-Asynchronous motor rotor time constant adjustment device; 101-First acquisition module; 102-Second acquisition module; 103-First calculation module; 104-Second calculation module; 105-Processing module. Detailed Implementation

[0049] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0050] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0051] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0052] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0053] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0054] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0055] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0056] Example 1: This example provides a method for adjusting the rotor time constant of an asynchronous motor. (See attached document.) Figure 1 ,include:

[0057] S100: Obtain the rotor electric angular velocity, rotor resistance, and inductance of the motor, and calculate the initial rotor time constant based on the rotor resistance and inductance;

[0058] Specifically, in this embodiment, the rotor time constant (τ) r According to the rotor resistance (R) s ) and inductance (L m The initial rotor time constant is obtained by using the ratio of the rotor resistance to the rotor resistance. That is, The rotor time constant is calculated based on the actual measured resistance and inductance. However, this calculated rotor time constant may deviate from the actual accurate value, thus affecting the control I based on the calculation. d I q In cases where the calculation is inaccurate, this application adjusts the parameters based on the calculated initial rotor time constant. That is, the parameters in S100 above and S200 below are collected while the asynchronous motor is operating at a certain rotor time constant.

[0059] S200: Obtain the three-phase current and three-phase voltage of the motor, and obtain the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current based on the initial rotor time constant, the three-phase current, and the three-phase voltage;

[0060] Specifically, in the above steps, the acquisition of three-phase current and three-phase voltage is mainly used for the calculation of the first torque and the second torque, and the stator α-axis current (I sα ), stator β-axis current (I sβ ), stator α-axis voltage (U sα ), stator β-axis voltage (U sβ ) and stator d-axis current (I sd ), stator q-axis current (I) sq All of these calculations are based on the initial rotor time constant mentioned above. The transformations are performed based on the initial rotor time constant, the three-phase current, and the three-phase voltage. Specifically, they are calculated based on the three-phase current and the three-phase voltage through Clark transformation and / or Park transformation.

[0061] S300: The rotor d-axis flux linkage and rotor q-axis flux linkage are obtained based on the rotor electric angular velocity using a current model. The first torque is calculated based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current.

[0062] Specifically, the rotor d-axis flux linkage and rotor q-axis flux linkage are obtained using a current model based on the rotor's electric angular velocity, including:

[0063] The current model is expressed as: ;

[0064] in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; The rotor's electric angular velocity; As a variable; , These are the stator d-axis current and stator q-axis current, respectively.

[0065] For illustrative purposes, in the above current model To allow for arbitrary assignment of rotational speed, when calculating the rotor d-axis flux linkage and rotor q-axis flux linkage based on the aforementioned current model, the variables are assigned the rotor electric angular velocity and then subjected to a Laplace transformation in the current model to calculate the rotor d-axis flux linkage and rotor q-axis flux linkage.

[0066] That is, based on the above current model, let = After performing a Laplace transform, we can obtain:

[0067] ; After transformation, the following can be obtained:

[0068] Specifically, the rotor d-axis flux linkage and rotor q-axis flux linkage are represented as follows: ;

[0069] in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; , These are the stator d-axis current and the stator q-axis current, respectively.

[0070] Specifically, the first torque is expressed as: ;

[0071] in, K represents the first torque; K2 represents the preset parameters. , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. , These are the stator d-axis current and the stator q-axis current, respectively.

[0072] Specifically, the first torque calculated above is the torque calculated based on the rotor flux linkage. Since the rotor time constant is obtained from the measured inductance and resistance, there may be inaccuracies.

[0073] S400: The stator α-axis flux linkage and stator β-axis flux linkage are obtained using a voltage model. The second torque is calculated based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current.

[0074] Specifically, obtaining the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model includes:

[0075] The voltage model is represented as follows: ;

[0076] in, , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and β current, respectively. For rotor resistance; , These are the stator α-axis voltage and the stator β-axis voltage, respectively.

[0077] The second torque is expressed as: ;

[0078] in, These represent the second torque; K 1为 Preset parameters; , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and the stator β-axis current, respectively.

[0079] The second torque calculated above is based on the stator flux linkage. It is not affected by the working state, temperature, etc., and does not depend on the rotor flux linkage. Therefore, the second torque is an accurate value. In this application, the adjustment of the rotor time constant is achieved by adjusting the value calculated by the first torque based on the accurate value calculated by the second torque.

[0080] S500: The initial rotor time constant is adjusted so that the deviation of the first torque relative to the second torque is within a preset range, so as to generate a rotor time constant compensation value.

[0081] Specifically, in this embodiment, the rotor time constant is adjusted by a PI controller, so that the first torque calculated from the initial rotor time constant gradually approaches the second torque, i.e., the error between the two is gradually reduced. A PI controller is a linear controller that uses the control deviation between the given value and the actual output value as a basis. The proportional and integral components of this deviation are linearly combined to form the control quantity, which controls the controlled object (in this embodiment, the rotor time constant). It should be noted that other control methods can also be used to adjust the rotor time constant in the first torque based on the second torque, including but not limited to adjustments with preset steps.

[0082] S600: Compensate the initial rotor time constant according to the rotor time constant compensation value.

[0083] Specifically, in step S500 above, the rotor time constant compensation value can be obtained through the PI controller. Then, compensation is performed based on the initial rotor time constant to obtain the rotor time constant under the actual torque. Based on this, the stator d-axis current, stator q-axis current, torque control, etc. are calculated with high accuracy.

[0084] As can be seen, in this embodiment, the torque calculated using the stator flux linkage (stator α-axis flux linkage, stator β-axis flux linkage) is used to adjust the torque calculated based on the rotor flux linkage, thereby adjusting the rotor time constant to make it conform to the actual operating scenario, improving the accuracy of the decomposition of the d / stator q-axis current based on this calculation, and thus improving the accuracy of torque control.

[0085] Example 2: The present invention also provides an adjustment device 10 for the rotor time constant of an asynchronous motor, see reference. Figure 3 The adjustment method implemented in Example 1 specifically includes:

[0086] The first acquisition module 101 is used to acquire the rotor electrical angular velocity, resistance and inductance of the motor, and calculate the initial rotor time constant based on the resistance and inductance; specifically, the initial rotor time constant is obtained by using the ratio of the inductance to the rotor resistance.

[0087] The second acquisition module 102 is used to acquire the three-phase current and three-phase voltage of the motor, and transform the three-phase current and three-phase voltage based on the initial rotor time constant to obtain the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current; specifically, it is calculated based on the three-phase current and three-phase voltage through Clark transformation and / or Park transformation.

[0088] The first calculation module 103 is used to obtain the rotor d-axis flux linkage and rotor q-axis flux linkage based on the rotor electric angular velocity using a current model, and to calculate the first torque based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current.

[0089] The second calculation module 104 is used to obtain the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model, and to calculate the second torque based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current.

[0090] The processing module 105 is used to adjust the initial rotor time constant based on the initial rotor time constant, so that the deviation of the first torque relative to the second torque is within a preset range, thereby generating a rotor time constant compensation value; and to compensate the initial rotor time constant according to the rotor time constant compensation value. Specifically, a PI controller is used to adjust the initial rotor time constant.

[0091] In this embodiment, the rotor electric angular velocity, initial rotor time constant, stator α-axis current (Isα), stator β-axis current (Isβ), stator α-axis voltage (Usα), stator β-axis voltage (Usβ), stator d-axis current (Isd), and stator q-axis current (Isq) are acquired by the first acquisition module and the second acquisition module. Then, the second torque based on the stator flux linkage and the first torque based on the rotor flux linkage are calculated in stages in the first calculation module and the second calculation module. In the processing module, the rotor flux linkage in the first torque is adjusted according to the second torque to determine the rotor time constant compensation value. Compensation is performed based on the initial rotor time constant to obtain a rotor time constant that matches the actual value, so as to achieve precise torque control.

[0092] Example 3: The present invention also provides an asynchronous motor current correction method, see below. Figure 2 Including the following:

[0093] S700-1: Collects the three-phase current of the motor;

[0094] Specifically, as an explanation, the initial d-axis current and q-axis current can be obtained from the three-phase current. They are obtained by decomposing the rotor time constant before adjustment (i.e., the initial rotor time constant, which can be calculated to obtain the value of the rotor flux linkage angle before the update below), which is consistent with the one obtained in step S200 above. This embodiment corrects it based on this.

[0095] S700: Based on the method for adjusting the rotor time constant of the asynchronous motor in Embodiment 1, the adjusted rotor time constant is obtained, and the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage are calculated according to the current model;

[0096] Specifically, the compensated rotor time constant can be obtained according to step S600 above, and the rotor d-axis flux linkage can be calculated according to the current model of the first embodiment above. Rotor q-axis flux .

[0097] S800: Calculate the adjusted stator α-axis flux linkage and stator β-axis flux linkage based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage, and rotor electric angular velocity; update the rotor flux linkage angle through trigonometric transformation based on the adjusted stator α-axis flux linkage and stator β-axis flux linkage;

[0098] Specifically, the step of calculating the adjusted stator α-axis flux linkage and stator β-axis flux linkage based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity includes: performing an inverse Park transformation on the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage based on the rotor electric angular velocity to obtain the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

[0099] That is, based on Perform an inverse Park transform on the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage to obtain the adjusted rotor time constant. , Then according to ,in It is the rotor flux linkage angle.

[0100] S900: Obtain the target d-axis current and target q-axis current based on the updated rotor flux angle and the three-phase current.

[0101] Specifically, based on the rotor flux linkage angle calculated using the adjusted rotor time constant mentioned above... The three-phase current is decomposed into d-axis and q-axis values ​​to obtain accurate stator d-axis and stator q-axis currents, and solid corrections are made to the stator d-axis and stator q-axis currents.

[0102] Example 4: The present invention also provides an asynchronous motor current correction system 11, see reference. Figure 3 The method includes transmitting data with the asynchronous motor rotor time constant adjustment device 10, or includes the asynchronous motor rotor time constant adjustment device 10, and implementing the correction method described in Embodiment 3 above, including:

[0103] The pre-control module 111 is used to collect the three-phase current of the motor;

[0104] The adjustment module 112 is used to obtain the adjusted rotor time constant from the adjustment device of the asynchronous motor rotor time constant according to the three-phase current, calculate the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage according to the current model; calculate the adjusted stator α-axis flux linkage and stator β-axis flux linkage according to the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity; and update the rotor flux linkage angle through trigonometric transformation according to the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

[0105] The correction module 113 is used to obtain the corrected stator d-axis current and stator q-axis current based on the updated rotor flux linkage angle and the three-phase current of the motor.

[0106] In this embodiment, a pre-control module controls the d-axis current and q-axis current (before adjusting the rotor time constant). After the asynchronous motor rotor time constant adjustment device calculates the adjusted rotor time constant, the adjustment module updates the rotor flux linkage angle according to the current model. Finally, the correction module obtains accurate d-axis and q-axis currents based on the updated rotor flux linkage angle, so that the d-axis and q-axis currents are consistent with the actual working conditions, thereby improving torque control accuracy.

[0107] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for adjusting the rotor time constant of an asynchronous motor, characterized in that, include: Obtain the rotor electrical angular velocity, resistance, and inductance of the motor, and calculate the initial rotor time constant based on the resistance and inductance; The three-phase current and three-phase voltage of the motor are obtained, and the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current are obtained based on the initial rotor time constant, the three-phase current, and the three-phase voltage. The rotor d-axis flux linkage and rotor q-axis flux linkage are obtained using a current model based on the rotor electric angular velocity. The first torque is then calculated based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current. The stator α-axis flux linkage and stator β-axis flux linkage are obtained using a voltage model. The second torque is calculated based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current. The rotor time constant is adjusted based on the initial rotor time constant so that the deviation of the first torque relative to the second torque is within a preset range, thereby generating a rotor time constant compensation value. The initial rotor time constant is compensated according to the rotor time constant compensation value.

2. The adjustment method according to claim 1, characterized in that: A PI controller is used to adjust the rotor time constant.

3. The adjustment method according to claim 1, characterized in that, The method of obtaining the rotor d-axis flux linkage and rotor q-axis flux linkage based on the rotor electric angular velocity using a current model includes: The current model is expressed as: ; in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; The rotor's electric angular velocity; As a variable; , These are the stator d-axis current and stator q-axis current, respectively. In the current model, the variables are assigned the rotor electric angular velocity and then subjected to a Laplace transform to calculate the rotor d-axis flux linkage and rotor q-axis flux linkage.

4. The adjustment method according to claim 3, characterized in that: The rotor d-axis flux linkage and rotor q-axis flux linkage are represented as follows: ; in, , These are the rotor d-axis flux linkage and the rotor q-axis flux linkage, respectively. It is an inductor; The rotor time constant; , These are the stator d-axis current and the stator q-axis current, respectively.

5. The adjustment method according to claim 1, characterized in that, The method of obtaining the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model includes: The voltage model is represented as follows: ; in, , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and stator β-axis current, respectively. For rotor resistance; , These are the α-axis voltage and the stator β-axis voltage, respectively.

6. The adjustment method according to claim 1, characterized in that: The first torque is expressed as: ; The second torque is expressed as: ; in, , These represent the first torque and the second torque, respectively; K1 and K2 are preset parameters. , These are the rotor d-axis flux linkage and rotor q-axis flux linkage, respectively. , These are the stator α-axis flux linkage and the stator β-axis flux linkage, respectively. , These are the stator α-axis current and stator β-axis current, respectively. , These are the stator d-axis current and the stator q-axis current, respectively.

7. A method for correcting the current of an asynchronous motor, characterized in that, include: Collect the three-phase current of the motor; According to the method for adjusting the rotor time constant of the asynchronous motor as described in claim 1 and the three-phase current to obtain the adjusted rotor time constant, the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage are calculated according to the current model. The adjusted stator α-axis flux linkage and stator β-axis flux linkage are calculated based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity. The rotor flux linkage angle is updated through trigonometric transformation based on the adjusted stator α-axis flux linkage and stator β-axis flux linkage. The target d-axis current and target q-axis current are obtained based on the updated rotor flux angle and the three-phase current.

8. The current correction method according to claim 7, characterized in that, The calculation of the adjusted stator α-axis flux linkage and stator β-axis flux linkage based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage, and rotor electric angular velocity includes: Based on the rotor electric angular velocity, the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage are subjected to inverse Park transformation to obtain the adjusted stator α-axis flux linkage and stator β-axis flux linkage.

9. A device for adjusting the rotor time constant of an asynchronous motor, characterized in that, include: The first acquisition module is used to acquire the rotor electric angular velocity, resistance and inductance of the motor, and calculate the initial rotor time constant based on the resistance and inductance. The second acquisition module is used to acquire the three-phase current and three-phase voltage of the motor, and transform the three-phase current and three-phase voltage based on the initial rotor time constant to obtain the stator α-axis current, stator β-axis current, stator α-axis voltage, stator β-axis voltage, stator d-axis current, and stator q-axis current. The first calculation module is used to obtain the rotor d-axis flux linkage and rotor q-axis flux linkage based on the rotor electric angular velocity using a current model, and to calculate the first torque based on the rotor d-axis flux linkage, rotor q-axis flux linkage, initial rotor time constant, stator d-axis current, and stator q-axis current. The second calculation module is used to obtain the stator α-axis flux linkage and stator β-axis flux linkage using a voltage model, and to calculate the second torque based on the stator α-axis flux linkage, stator β-axis flux linkage, stator α-axis voltage, stator β-axis voltage, stator α-axis current, and stator β-axis current. The processing module is used to adjust the rotor time constant based on the initial rotor time constant, so that the deviation of the first torque relative to the second torque is within a preset range, so as to generate a rotor time constant compensation value; and to compensate the initial rotor time constant according to the rotor time constant compensation value.

10. An asynchronous motor current correction system, characterized in that, include: The pre-control module is used to collect the three-phase current of the motor; The adjustment module is used to obtain the adjusted rotor time constant from the asynchronous motor rotor time constant adjustment device as described in claim 9 based on the three-phase current, calculate the adjusted rotor d-axis flux linkage and rotor q-axis flux linkage based on the current model; calculate the adjusted stator α-axis flux linkage and stator β-axis flux linkage based on the adjusted rotor d-axis flux linkage, rotor q-axis flux linkage and rotor electric angular velocity; and update the rotor flux linkage angle through trigonometric transformation based on the adjusted stator α-axis flux linkage and stator β-axis flux linkage. The correction module is used to obtain the target d-axis current and the target q-axis current based on the updated rotor flux linkage angle and the three-phase current.

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