An estimation method and system for the rotor temperature of an asynchronous motor

Abstract

The present invention provides an estimation method and system for the rotor temperature of an asynchronous motor. The estimation method comprises the following steps: under an experimental environment, collecting the rotor temperature Temp and the time constant T of the asynchronous motor at any time. r The relationship between the rotor temperature Temp and the time constant T is recorded as the relationship data; the fixed current is changed, and the relationship data is continuously obtained and stored as the rotor temperature Temp and the time constant T r Relationship table; Get the stator α-axis flux ψ of the asynchronous motor sα and stator β-axis flux ψ sβ ; Based on the stator α-axis flux ψ sα and β-axis flux ψ sβ The flux linkage with the rotor α axis ψ rα and rotor β-axis flux ψ rβ Calculate the rotor α-axis flux ψ rα and rotor β-axis flux ψ rβ ; Calculate the rotor magnetic field angle θ ψr and the rotor magnetic field angular velocity ω e ; Calculate the rotor magnetic field angular velocity ω e The rotor electrical angular velocity ω of the asynchronous motor r The difference between the two is used to obtain the time constant T r ; Set the time constant T r Substitute into the relationship table to obtain the rotor temperature Temp of the asynchronous motor. After adopting the above technical solution, the rotor temperature can be quickly and accurately obtained by evaluating the motor state.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and particularly to a method and system for estimating the rotor temperature of an asynchronous motor. Background Art

[0002] With the rapid development of new energy vehicles, various controls of the motors in new energy vehicles have become the key factors for differentiating new energy vehicles.

[0003] Among them, in engineering practice, how to quickly and accurately monitor the rotor temperature of an asynchronous motor is of great significance for motor state evaluation, over-temperature protection, etc. However, due to operating conditions, it is very difficult to directly measure the rotor temperature. Even the rotor temperature obtained indirectly has a certain deviation from the actual temperature, or the acquisition time is too long, and the data obtained is not accurate.

[0004] Therefore, a new method for estimating the rotor temperature of an asynchronous motor is needed, and the estimation method is simple and has high accuracy. Summary of the Invention

[0005] In order to overcome the above technical defects, the purpose of the present invention is to provide a method and system for estimating the rotor temperature of an asynchronous motor, and the rotor temperature can be quickly and accurately obtained through the evaluation of the motor state.

[0006] The present invention discloses a method for estimating the rotor temperature of an asynchronous motor, including the following steps:

[0007] Under an experimental environment, based on a fixed current passing through the asynchronous motor, collect the rotor temperature Temp of the asynchronous motor and a time constant T at any moment r of the relationship, and record it as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor;

[0008] Change the fixed current, continuously obtain the relationship data, and store it as a relationship table of the rotor temperature Temp and the time constant T r ;

[0009] Obtain the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ of the asynchronous motor from the motor controller;

[0010] Based on the relationship between the stator α-axis magnetic flux ψ sα and the β-axis magnetic flux ψ sβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, calculate and obtain the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor;

[0011] Based on the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ calculate the rotor magnetic field angle θ of the asynchronous motor ψr and the rotor magnetic field angular velocity ω e ;

[0012] Calculate the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω of the asynchronous motor r to obtain the time constant T r ;

[0013] Substitute the time constant T r into the relationship table to obtain the rotor temperature Temp of the asynchronous motor.

[0014] Preferably, the step of obtaining the stator α-axis flux linkage ψ and the stator β-axis flux linkage ψ of the asynchronous motor from the motor controller includes: sα and the stator β-axis flux linkage ψ sβ is as follows:

[0015] Collect the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ from the motor controller;

[0016] Based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ , and the known stator impedance R s , calculate the stator α-axis flux linkage ψ sα and the stator β-axis flux linkage ψ sβ respectively according to the following formulas:

[0017] ψ sα = ∫(u sα - R s i sα )dt, ψ sβ = ∫(u sβ - R s i sβ )dt.

[0018] Preferably, based on the relationship between the stator α-axis flux linkage ψ and the β-axis flux linkage ψ of the asynchronous motor sα and the rotor α-axis flux linkage ψ sβ and the rotor β-axis flux linkage ψ of the asynchronous motor rα and the rotor β-axis flux linkage ψ rβ calculate the rotor α-axis flux linkage ψ of the asynchronous motor rαand the rotor β-axis flux linkage ψ rβ The steps include:

[0019] Obtain the stator self-inductance L s , the mutual inductance L between the stator and the rotor m , the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ;

[0020] Based on the stator α-axis flux linkage ψ sα and β-axis flux linkage ψ sβ of the asynchronous motor and the rotor α-axis flux linkage ψ rα and rotor β-axis flux linkage ψ rβ of the following relationship:

[0021] Obtain the following calculation formula for the rotor α-axis flux linkage ψ rα and rotor β-axis flux linkage ψ rβ :

[0022]

[0023] Preferably, based on the rotor α-axis flux linkage ψ rα and rotor β-axis flux linkage ψ rβ calculate to obtain the rotor magnetic field angle θ ψr and rotor magnetic field angular velocity ω e The steps include:

[0024] Calculate the rotor magnetic field angle θ ψr according to the following formula:

[0025]

[0026] Calculate the rotor magnetic field angular velocity ω e according to the following formula:

[0027]

[0028] Preferably, calculate the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor to obtain the time constant T r The steps include:

[0029] Calculate the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor:

[0030]

[0031] Read the stator q-axis current i in the motor controller sq and the stator d-axis current i sd , and calculate the time constant T according to the following formula r :

[0032]

[0033] The present invention also discloses an estimation system for the rotor temperature of an asynchronous motor, including:

[0034] An experimental component, in an experimental environment, based on a fixed current passing through the asynchronous motor, the experimental component collects the rotor temperature Temp of the asynchronous motor and a time constant T r at any moment, and records them as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor;

[0035] The experimental component changes the fixed current, continuously obtains the relationship data, and stores it as a relationship table of the rotor temperature Temp and the time constant T r ;

[0036] A calculation module, which obtains the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ of the asynchronous motor from the motor controller;

[0037] Based on the relationship between the stator α-axis magnetic flux ψ sα and the β-axis magnetic flux ψ sβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, the calculation module calculates and obtains the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor;

[0038] Based on the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ , the calculation module calculates and obtains the rotor magnetic field angle θ ψr and the rotor magnetic field angular velocity ω e of the asynchronous motor;

[0039] The calculation module calculates the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor to obtain the time constant T r ;

[0040] The calculation module substitutes the time constant T r into the relationship table to obtain the rotor temperature Temp of the asynchronous motor.

[0041] Preferably, the calculation module collects the stator α-axis voltage u of the asynchronous motor from the motor controller sα and the stator β-axis voltage u sβ 、the stator α-axis current i sα and the stator β-axis current i sβ ;

[0042] The calculation module is based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ 、the stator α-axis current i sα and the stator β-axis current i sβ 、the known stator impedance R s , and respectively calculates the stator α-axis flux linkage ψ sα and the stator β-axis flux linkage ψ sβ according to the following formula:

[0043] ψ sα =∫(u sα -R s i sα )dt、ψ sβ =∫(u sβ -R s i sβ )dt.

[0044] Preferably, the calculation module obtains the stator self-inductance L s 、the stator-rotor mutual inductance L m 、the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ;

[0045] The calculation module is based on the stator α-axis flux linkage ψ of the asynchronous motor sα and the β-axis flux linkage ψ sβ and the following relationship between the rotor α-axis flux linkage ψ of the asynchronous motor rα and the rotor β-axis flux linkage ψ rβ :

[0046] Obtain the following calculation formulas for the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ :

[0047]

[0048] Preferably, the calculation module calculates the rotor magnetic field angle θ ψr according to the following formula:

[0049]

[0050] The calculation module calculates the angular velocity ω of the rotor magnetic field according to the following formula e :

[0051]

[0052] Preferably, the calculation module calculates the angular velocity ω of the rotor magnetic field according to the following formula e and the difference from the electrical angular velocity ω r of the rotor of the asynchronous motor:

[0053]

[0054] The calculation module reads the stator q-axis current i sq and the stator d-axis current i sd in the motor controller, and calculates the time constant T according to the following formula r :

[0055]

[0056] After adopting the above technical solution, compared with the prior art, it has the following beneficial effects:

[0057] 1. At high speeds of the motor, the rotor temperature can still be estimated;

[0058] 2. The estimation result of the rotor temperature is accurate and fast. Description of the Drawings

[0059] Figure 1 It is a schematic flowchart of the method for estimating the rotor temperature of an asynchronous motor according to a preferred embodiment of the present invention. Detailed Embodiments

[0060] The advantages of the present invention are further elaborated below in conjunction with the drawings and specific embodiments.

[0061] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. 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 present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0062] The terms used in the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present 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.

[0063] 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 only used to distinguish information of the same type from each other. For example, without departing from the scope of this disclosure, 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 word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0064] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0065] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a mechanical connection or an electrical connection, or it may be the communication inside two elements. It may be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms may be understood according to specific circumstances.

[0066] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only for the convenience of describing the present invention, and they do not have a specific meaning in themselves. Therefore, "module" and "component" can be used interchangeably.

[0067] Refer to Figure 1 , which shows an estimation method for the rotor temperature of an asynchronous motor in a preferred embodiment of the present invention, characterized by including the following steps:

[0068] S100: In an experimental environment, based on a fixed current passing through the asynchronous motor, collect the relationship between the rotor temperature Temp of the asynchronous motor and a time constant T r at any moment, and record it as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor;

[0069] In the test environment or experimental environment of the motor controller, a simulated working scenario of the asynchronous motor is established. The asynchronous motor is powered on with any fixed current. As the power-on process continues, the asynchronous motor will continue to operate and generate heat due to the operation of mechanical components, causing the rotor temperature of the rotor to gradually increase. Thus, at any moment after operation, the current rotor temperature Temp and the time constant T at the current moment can be obtained through the temperature sensor set in the asynchronous motor. r Record the two arrays as a set of relationship data. In the above process, the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor at the current moment and can be obtained through the existing parameters of the motor and the motor controller.

[0070] S200: Change the fixed current, continuously obtain the relationship data, and store it as a relationship table of the rotor temperature Temp and the time constant T r ;

[0071] In the experimental environment, continue to change the magnitude of the fixed current passed previously and continuously record the relationship data at different moments until a large amount of data is obtained, and then it can be stored as a relationship table of the rotor temperature Temp and the time constant T r ;

[0072] S300: Obtain the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ of the asynchronous motor from the motor controller;

[0073] In this step, the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ of the asynchronous motor will be directly read from the motor controller, and the values will be stored for calculation in subsequent steps.

[0074] S400: Based on the relationship between the stator α-axis magnetic flux ψ sα and the β-axis magnetic flux ψ sβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, calculate and obtain the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor;

[0075] Since there is a certain relationship between the stator α-axis magnetic flux ψ sα and the β-axis magnetic flux ψ sβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, then according to the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ obtained in step S300sβ The value accurately calculates the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, avoiding the difficulty in obtaining the above data of the rotor that is rotating at high speed in the prior art.

[0076] S500: Based on the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ calculate the rotor magnetic field angle θ ψr and the rotor magnetic field angular velocity ω e of the asynchronous motor.

[0077] After obtaining the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the asynchronous motor, the rotor magnetic field angle θ ψr and the rotor magnetic field angular velocity ω e can be calculated. In the prior art, the rotor magnetic field angle is generally indirectly calculated through the integration of the motor rotor speed and the motor slip. For example, the rotor speed can be directly collected from the encoder, and the motor slip can be calculated from the torque current feedback of the motor and the current magnetic flux amplitude of the motor. In this embodiment, the rotor magnetic field angle θ ψr and the rotor magnetic field angular velocity ω e can be obtained through further calculation, saving calculation time.

[0078] S600: Calculate the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor to obtain the time constant T r ;

[0079] In this step, the time constant T e under the actual working condition is calculated by the difference between the rotor magnetic field angular velocity ω r and the rotor electrical angular velocity ω r of the asynchronous motor.

[0080] S700: Substitute the time constant T r into the relationship table to obtain the rotor temperature Temp

[0081] of the asynchronous motor. Finally, substitute the time constant T r under the actual working condition into the relationship table, so as to obtain the rotor temperature Temp of the asynchronous motor corresponding to the current time constant T r at the current moment in the actual working condition. The obtained rotor temperature Temp can be regarded as the estimated rotor temperature at the current moment.

[0082] Through the above calculation method, a large amount of complex data calculation can be avoided. As the calibration data in the experimental environment becomes richer, the accuracy of the estimated rotor temperature Temp will also be improved.

[0083] In a preferred embodiment, step S300 includes:

[0084] S310: Collect the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ from the motor controller;

[0085] In the motor controller, the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ can be obtained and calculated through a three-phase circuit and current sensors. The calculation method depends on the capabilities of the current sensors. For example, the above data can be calculated internally after collecting three-phase currents.

[0086] S320: Based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ , and the known stator impedance R s , calculate the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ respectively according to the following formulas:

[0087] ψ sα = ∫(u sα - R s i sα )dt, ψ sβ = ∫(u sβ - R s i sβ )dt, that is, calculate the integral of the stator loss voltage with respect to time to obtain the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ .

[0088] Furthermore, step S400 includes:

[0089] S410: Obtain the stator self-inductance L s , the stator-rotor mutual inductance L m , the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ;

[0090] Stator self-inductance L s , stator-rotor mutual inductance L m , rotor self-inductance L r and rotor α-axis current i rα and rotor β-axis current i sβ Data can be obtained from the asynchronous motor manufacturer. The parameters of each asynchronous motor may vary slightly, which are related to the materials and processes during manufacturing.

[0091] S420: Based on the stator α-axis magnetic flux ψ sα and β-axis magnetic flux ψ sβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and rotor β-axis magnetic flux ψ rβ of the asynchronous motor, the following relationship:

[0092]

[0093] After rewriting the above relationship, the following calculation formulas for the rotor α-axis magnetic flux ψ rα and rotor β-axis magnetic flux ψ rβ are obtained:

[0094] It can be seen from the above calculation formulas that through the existing parameters, and the stator α-axis magnetic flux ψ sα and β-axis magnetic flux ψ sβ at any moment, the rotor α-axis magnetic flux ψ rα and rotor β-axis magnetic flux ψ rβ at the current moment can be calculated.

[0095] Furthermore, step S500 includes:

[0096] S510: Calculate the rotor magnetic field angle θ ψr according to the following formula:

[0097] S520: Calculate the rotor magnetic field angular velocity ω e according to the following formula:

[0098] Most preferably, step S600 includes:

[0099] S610: Finally, calculate the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor according to the following formula: The difference between the two is also the ratio of the q-axis current to the d-axis current, and a time constant is superimposed.

[0100] S620: Read the stator q-axis current i sq and stator d-axis current isd , and calculate the time constant T according to the following formula r :[[]]

[0101] The source of the above formula mainly considers the ratio of the rotor inductance to the rotor impedance of the asynchronous motor, that is And the rotor impedance is related to temperature.[[]]

[0102] The present invention also discloses an estimation system for the rotor temperature of an asynchronous motor, including: an experimental component, in an experimental environment, based on a fixed current passing through the asynchronous motor, the experimental component collects the rotor temperature Temp of the asynchronous motor and a time constant T r at any moment, and records it as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor; the experimental component changes the fixed current, continuously obtains the relationship data, and stores it as a relationship table of the rotor temperature Temp and the time constant T r ; a calculation module, obtains the stator α-axis magnetic flux ψ sα and the stator β-axis magnetic flux ψ sβ of the asynchronous motor from the motor controller; the calculation module calculates and obtains the rotor α-axis magnetic flux ψ sα and the rotor β-axis magnetic flux ψ sβ of the asynchronous motor based on the relationship between the stator α-axis magnetic flux ψ rα and the β-axis magnetic flux ψ rβ of the asynchronous motor and the rotor α-axis magnetic flux ψ rα and the rotor β-axis magnetic flux ψ rβ of the rotor; the calculation module calculates and obtains the rotor magnetic field angle θ rα and the rotor magnetic field angular velocity ω rβ of the asynchronous motor based on the rotor α-axis magnetic flux ψ ψr and the rotor β-axis magnetic flux ψ e ; the calculation module calculates the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor to obtain the time constant T r ; the calculation module substitutes the time constant T r into the relationship table to obtain the rotor temperature Temp of the asynchronous motor.[[]]

[0103] Preferably, the calculation module collects the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ of the asynchronous motor from the motor controller; the calculation module is based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sαand the stator β-axis current i sβ , the known stator impedance R s , calculate the stator α-axis flux linkage ψ sα and the stator β-axis flux linkage ψ sβ respectively according to the following formulas: ψ sα = ∫(u sα - R s i sα )dt, ψ sβ = ∫(u sβ - R s i sβ )dt.

[0104] Preferably, the calculation module obtains the stator self-inductance L s , the stator-rotor mutual inductance L m , the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ; the calculation module is based on the stator α-axis flux linkage ψ sα and β-axis flux linkage ψ sβ of the asynchronous motor and the rotor α-axis flux linkage ψ rα and rotor β-axis flux linkage ψ rβ of the asynchronous motor, and the following relationship: to obtain the following calculation formulas for the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ :

[0105] Preferably, the calculation module calculates the rotor magnetic field angle θ ψr according to the following formula:

[0106] The calculation module calculates the rotor magnetic field angular velocity ω e according to the following formula:

[0107] Preferably, the calculation module calculates the difference between the rotor magnetic field angular velocity ω e and the rotor electrical angular velocity ω r of the asynchronous motor: The calculation module reads the stator q-axis current i sq and the stator d-axis current i sd in the motor controller, and calculates the time constant T r according to the following formula:

[0108] It should be noted that the embodiments of the present invention have better implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the technical content disclosed above to modify or transform it into equivalent effective embodiments. However, as long as the content does not depart from the technical solution of the present invention, any modification, equivalent change, or modification made to the above embodiments based on the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. An estimation method for the rotor temperature of an asynchronous motor, characterized in that, including the following steps: Under an experimental environment, based on a fixed current of an asynchronous motor, at any moment, the rotor temperature Temp of the asynchronous motor and a time constant T r are related, and are recorded as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor; Change the fixed current, continuously obtain relationship data, and store it as a relationship table of rotor temperature Temp and time constant T r ; Obtain the stator α-axis flux linkage ψ of the asynchronous motor from the motor controller sα and the stator β-axis flux linkage ψ sβ ; Based on the stator α-axis flux linkage ψ of the asynchronous motor sα and the β-axis flux linkage ψ sβ of the asynchronous motor, and the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ of the asynchronous motor, calculate and obtain the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ ; Based on the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ calculate the rotor magnetic field angle θ of the asynchronous motor ψr and the rotor magnetic field angular velocity ω e ; Calculate the angular velocity ω of the rotor magnetic field e and the difference from the electrical angular velocity ω r of the rotor of the induction motor to obtain the time constant T r ; Substitute the time constant T r into the relational table to obtain the rotor temperature Temp of the induction motor.

2. The estimation method according to claim 1, wherein Obtain the stator α-axis flux linkage ψ of the asynchronous motor from the motor controller sα and the stator β-axis flux linkage ψ sβ The steps include: Collect the stator α-axis voltage u of the asynchronous motor from the motor controller sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ ; Based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ , and the known stator impedance R s , calculate the stator α-axis flux linkage ψ sα and the stator β-axis flux linkage ψ sβ respectively according to the following formulas: ψ sα = ∫(u sα - R s i sα )dt, ψ sβ = ∫(u sβ - R s i sβ )dt.

3. The estimation method according to claim 2, wherein Based on the stator α-axis flux linkage ψ of the asynchronous motor sα and the stator β-axis flux linkage ψ sβ and the rotor α-axis flux linkage ψ of the asynchronous motor rα and the rotor β-axis flux linkage ψ rβ The steps for calculating the rotor α-axis flux linkage ψ and the rotor β-axis flux linkage ψ of the asynchronous motor are as follows: rα and the rotor β-axis flux linkage ψ rβ include: Obtain the stator self-inductance L s , the mutual inductance L between the stator and the rotor m , the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ; Based on the stator α-axis flux linkage ψ of the asynchronous motor sα and the stator β-axis flux linkage ψ sβ and the rotor α-axis flux linkage ψ of the asynchronous motor rα and the rotor β-axis flux linkage ψ rβ the following relationship: The following calculation formulas for the rotor α-axis magnetic flux linkage ψ rα and the rotor β-axis magnetic flux linkage ψ rβ are obtained:

4. The estimation method according to claim 3, wherein Based on the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ Calculating to obtain the rotor magnetic field angle θ of the asynchronous motor ψr and the rotor magnetic field angular velocity ω e The steps are as follows: Calculate the rotor magnetic field angle θ according to the following formula ψr :[[]]END]] Calculate the rotor magnetic field angular velocity ω according to the following formula e :[[]]END]] 5. The estimation method according to claim 4, characterized in that Calculate the angular velocity ω of the rotor magnetic field e and the angular velocity ω r of the rotor of the asynchronous motor to obtain the time constant T r The steps include: Calculate the rotor magnetic field angular velocity ω according to the following formula e and the rotor electrical angular velocity ω r of the asynchronous motor: Read the stator q-axis current i in the motor controller sq and the stator d-axis current i sd , and calculate the time constant T according to the following formula r :

6. An estimation system for the rotor temperature of an asynchronous motor, characterized in that, including: Experimental component. In an experimental environment, based on a fixed current of an asynchronous motor, the experimental component collects the rotor temperature Temp of the asynchronous motor and a time constant T at any moment, r and records them as a set of relationship data, where the time constant T r is the ratio of the rotor inductance to the rotor impedance of the asynchronous motor; The experimental component changes the fixed current, continuously obtains relationship data, and stores it as a relationship table of the rotor temperature Temp and the time constant T r ; Calculation module, obtaining the stator α-axis magnetic flux ψ of the asynchronous motor from the motor controller sα and the stator β-axis magnetic flux ψ sβ ; The calculation module calculates the rotor α-axis flux linkage ψ sα and the β-axis flux linkage ψ sβ of the asynchronous motor based on the relationship with the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ of the asynchronous motor, and obtains the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ ; The calculation module calculates the rotor magnetic field angle θ rα and the rotor flux linkage ψ on the β-axis rβ of the asynchronous motor based on the rotor flux linkage ψ on the α-axis ψr and the rotor magnetic field angular velocity ω e ; The calculation module calculates the angular velocity ω of the rotor magnetic field e and the electrical angular velocity ω r of the rotor of the asynchronous motor to obtain the time constant T r ; the calculation module substitutes the time constant T r into the relationship table to obtain the rotor temperature Temp of the asynchronous motor.

7. The estimation system according to claim 6, characterized in that The calculation module collects the stator α-axis voltage u of the asynchronous motor from the motor controller sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ ; The calculation module is based on the stator α-axis voltage u sα and the stator β-axis voltage u sβ , the stator α-axis current i sα and the stator β-axis current i sβ , the known stator impedance R s , and respectively calculates the stator α-axis flux linkage ψ sα and the stator β-axis flux linkage ψ sβ according to the following formula: ψ sα = ∫(u sα - R s i sα ) dt, ψ sβ = ∫(u sβ - R s i sβ ) dt.

8. The estimation system according to claim 7, characterized in that The calculation module obtains the stator self-inductance L s , the stator-rotor mutual inductance L m , the rotor self-inductance L r and the rotor α-axis current i rα and the rotor β-axis current i sβ ; The calculation module is based on the stator α-axis magnetic flux ψ of the asynchronous motor sα and the β-axis magnetic flux ψ sβ and the following relationships with the rotor α-axis magnetic flux ψ of the asynchronous motor rα and the rotor β-axis magnetic flux ψ rβ : The following calculation formulas for the rotor α-axis flux linkage ψ rα and the rotor β-axis flux linkage ψ rβ are obtained:

9. The estimation system according to claim 8, characterized in that The calculation module calculates the rotor magnetic field angle θ according to the following formula ψr :[[]]END]] The calculation module calculates the angular velocity ω of the rotor magnetic field according to the following formula e :[[]]END]] 10. The estimation system according to claim 9, characterized in that The calculation module calculates the angular velocity ω of the rotor magnetic field according to the following formula e and the angular electrical velocity ω r of the asynchronous motor: The calculation module reads the stator q-axis current i sq and the stator d-axis current i sd in the motor controller, and calculates the time constant T according to the following formula r :

Images