Method, device and application for measuring position of rotor magnetic field of induction motor

Abstract

The present application relates to induction motor rotor magnetic field measurement technical field, more particularly, to rotor magnetic field position measurement method, adopt the rotor magnetic field position measurement method of rotor magnetic field position measurement device, both for induction motor rotor magnetic field measurement, and the application of the rotor magnetic field position measurement method, application in obtaining induction motor control parameter.The present application provides induction motor rotor magnetic field position measurement method, utilizes rotor current space vector and rotor magnetic field space angle relationship conversion, to obtain the real-time position of rotor magnetic field.The present application determines reference bar and auxiliary bar at the rotor side, and real-time measurement current value to establish rotor current space vector, and combine the real-time space position of reference bar to obtain the real-time position of rotor current space vector in stator coordinate system, and then obtain the real-time position of rotor magnetic field according to different working conditions.

Description

Technical Field

[0001] This invention relates to the field of induction motor rotor magnetic field measurement technology, and more specifically, to a rotor magnetic field position measurement method and a rotor magnetic field position measurement device using the rotor magnetic field position measurement method, both used for measuring the rotor magnetic field of an induction motor; and to the application of the rotor magnetic field position measurement method in obtaining induction motor control parameters. Background Technology

[0002] Rotor field-oriented control, due to its excellent decoupling characteristics, is widely used in the control of high-performance permanent magnet synchronous motors and induction motors. In permanent magnet synchronous motors, the rotor magnetic field position is aligned with the direction of the permanent magnet poles on the rotor, and the rotor magnetic field rotates synchronously with the rotor. Therefore, its position can be accurately measured directly using sensors such as photoelectric encoders or rotary transformers. However, in induction motors, to generate driving or braking torque, there is a slip between the rotor magnetic field rotation frequency and the rotor mechanical rotation frequency. The magnitude of this slip dynamically changes with different operating points, making it impossible to directly measure the rotor magnetic field position using traditional position sensors.

[0003] To achieve rotor field-oriented control for induction motors, scholars both domestically and internationally have conducted extensive research on rotor flux linkage position estimation. They have developed real-time rotor position estimation methods based on motor model parameters, such as current-flux linkage models, voltage-flux linkage models, and flux linkage observer models, achieving significant research results and numerous industrial applications. However, automotive induction motors typically operate at high temperatures, strong magnetic saturation, and wide speed ranges, with motor parameters exhibiting significant variations under different operating conditions. To construct an accurate rotor flux linkage position estimation model, it is necessary to calibrate the motor parameters at different operating points. Furthermore, the calibration of most motor parameters requires accurate rotor magnetic field position input as a prerequisite.

[0004] Since there is currently no effective method for real-time measurement of the rotor magnetic field position of an induction motor, it is difficult to: 1) assess the accuracy of the constructed rotor magnetic field position estimation scheme under different operating conditions; and 2) obtain various parameters of the induction motor at different operating points, which ultimately affects key performance indicators such as torque accuracy, system efficiency, and external characteristic range of the induction motor drive system. Summary of the Invention

[0005] Therefore, it is necessary to address the lack of an effective method for real-time measurement of the rotor magnetic field position of induction motors by providing a method, device, and application for measuring the rotor magnetic field position of induction motors.

[0006] This invention is achieved using the following technical solution:

[0007] In a first aspect, the present invention discloses a method for measuring the position of the magnetic field of an induction motor rotor, comprising the following steps:

[0008] S1, determine the rotor-side reference guide bar and auxiliary guide bar;

[0009] S1 includes: selecting one of the rotor's guide bars as a reference guide bar, and then determining auxiliary guide bars based on the reference guide bar;

[0010] S2, Establish the rotor current space vector in the reference guide bar coordinate system.

[0011] Where t represents time; the reference guide bar coordinate system is a coordinate system with the spatial position of the reference guide bar as the horizontal axis and leading the spatial electrical angle of the reference guide bar. A coordinate system with the vertical axis as the coordinate system;

[0012] S3, Extract the space vector of the rotor fundamental current in the reference conductor coordinate system.

[0013] S4, Calculate the spatial vector position θ of the rotor fundamental current in the stator coordinate system. ir (t):

[0014] S5, Determine the real-time position θ of the rotor magnetic field in the stator coordinate system. M (t);

[0015] Wherein, if the rotor magnetic field position is under the condition of positive torque output by the motor,

[0016] If the rotor magnetic field position is under negative torque output conditions, the rotor magnetic field position is:

[0017] This induction motor rotor magnetic field position measurement method implements the method or process disclosed in the embodiments of the present invention.

[0018] Secondly, the present invention discloses an induction motor rotor magnetic field position measuring device, which uses the induction motor rotor magnetic field position measuring method described in the first aspect.

[0019] The rotor magnetic field position measuring device includes a sensor module, a signal transmission module, and a signal calculation module. The sensor module acquires the real-time current of the reference and auxiliary conductors. The signal transmission module transmits the signals from the sensor module. The signal calculation module receives the rotor current signal transmitted from the signal transmission module, as well as the rotor position and slip signals acquired by the motor controller, and calculates the real-time rotor magnetic field position.

[0020] Thirdly, the present invention discloses the application of the induction motor rotor magnetic field position measurement method described in the first aspect, namely, its application in obtaining induction motor control parameters.

[0021] The application of this induction motor rotor magnetic field position measurement method realizes the method or process of the embodiments disclosed in this invention.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. This invention provides a method for measuring the rotor magnetic field position of an induction motor. The measured rotor magnetic field position can be used as the true value of the rotor magnetic field position to evaluate and correct different rotor magnetic field position estimation methods, so as to improve the estimation accuracy of the rotor magnetic field position in practical applications, thereby improving key performance indicators such as torque accuracy, system efficiency, and external characteristic range of the induction motor drive system.

[0024] 2. This invention accurately extracts the rotor current space vector. First, it performs reverse vector transformation and filtering, and then performs forward vector transformation to convert it into the rotor fundamental current space vector. This eliminates the influence of rotor current space vector harmonics on magnetic field position estimation, making subsequent measurement results more accurate. Attached Figure Description

[0025] Figure 1 This is a flowchart of the induction motor rotor magnetic field position measurement method in Embodiment 1 of the present invention;

[0026] Figure 2 for Figure 1 A schematic diagram showing the positional relationship of the auxiliary guide bar used in the time synchronization.

[0027] Figure 3 for Figure 1 Space vector of fundamental current in the rotor Extraction flowchart;

[0028] Figure 4 This is a structural diagram of the induction motor rotor magnetic field position measuring device in Embodiment 2 of the present invention;

[0029] Figure 5 for Figure 4 Layout diagram of the sensor module;

[0030] Figure 6 for Figure 4 A structural diagram of a brush-type signal transmission module used in the circuit.

[0031] Figure 7 for Figure 4 A schematic diagram showing the arrangement of telemetry signal transmission modules in the middle;

[0032] Figure 8 This is a schematic diagram illustrating an application scenario of the present invention;

[0033] Figure 9 The coupling relationship between motor parameter calibration and magnetic field position estimation;

[0034] Figure 10 This is a flowchart of obtaining motor control parameters in Embodiment 3 of the present invention;

[0035] Figure 11 This is the finite element simulation model in Embodiment 3 of the present invention;

[0036] Figure 12 The result of rotor current extraction calculation in Embodiment 3 of the present invention;

[0037] Figure 13 The result of the rotor magnetic field position calculation in Embodiment 3 of the present invention;

[0038] Figure 14 The results of current, flux linkage, and inductance in the rotor magnetic field coordinate system in Embodiment 3 of the present invention are shown. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] It should be noted that when a component is described as "installed on" another component, it can be on the other component or it can also be in a central component. When a component is described as "set on" another component, it can be set on the other component or it may also be in a central component. When a component is described as "fixed to" another component, it can be fixed on the other component or it may also be in a central component.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Example 1

[0043] Please see Figure 1 , Figure 1 This is a flowchart of the induction motor rotor magnetic field position measurement method of the present invention. This embodiment discloses an induction motor rotor magnetic field position measurement method, applicable to various types of induction motors such as squirrel-cage and wound-rotor motors.

[0044] The method for measuring the rotor magnetic field position of an induction motor includes the following steps:

[0045] S1: Determine the reference guide bar and auxiliary guide bar on the rotor side.

[0046] S2: Establish the rotor current space vector in the reference guide bar coordinate system Here, t represents time, and subsequent t representations have the same meaning, so they will not be explained again.

[0047] The reference guide bar coordinate system is a coordinate system with the spatial position of the reference guide bar as the horizontal axis and leading the spatial electrical angle of the reference guide bar. A coordinate system with the vertical axis as the coordinate system.

[0048] The purpose of S1 and S2 is to determine the reference and auxiliary conductors on the rotor side based on the existing conductor distribution, establish the reference conductor coordinate system, and then calculate the rotor current space vector.

[0049] S1 first selects one of the rotor's guide bars as the reference guide bar, and then determines the auxiliary guide bars based on the reference guide bar. There are two ways to determine the auxiliary guide bars: the first is a general case, and the second is a special case (based on the number of phases m of the induction motor rotor, where m is a multiple of 4). It should be noted that S2 differs for the two cases.

[0050] Specifically:

[0051] (a) The first method is to take counterclockwise as the positive direction and select the spatial electrical angle of the reference conductor ahead. The two guide bars that are symmetrically mirrored in position serve as auxiliary guide bars and form an auxiliary guide bar pair.

[0052] See Figure 2 , Figure 2 for Figure 1 A schematic diagram illustrating the time synchronization position relationship using auxiliary guide bars. For ease of explanation, Figure 2 The electrical angle in space is equivalent to the spatial angle.

[0053] It should be noted that the rotor bars are circumferentially uniformly distributed, thus leading or lagging the reference bar spatial electrical angle. The location allows you to find two symmetrically mirrored guide bars.

[0054] After determining the auxiliary guide bar pair, proceed to S2:

[0055] The real-time current I of the reference conductor is obtained using a current sensor. ref (t) Real-time current I of the two auxiliary conductors aux1 (t), I aux2 (t);

[0056] The real-time current I of the two auxiliary conductors aux1 (t), I aux2(t) is converted to the equivalent auxiliary conductor current value I' aux (t), where, Δθ is the difference in spatial electrical angle between the auxiliary conductor pairs;

[0057] Establish the rotor current space vector in the reference guide bar coordinate system Where, k w This is the equivalent coefficient for rotor current reduction.

[0058] (ii) The second method is that when the number of phases m of the induction motor rotor is a multiple of 4, the counterclockwise direction can also be used to select the spatial electrical angle of the leading reference guide bar. A single conductor bar is used as an auxiliary conductor bar.

[0059] After determining the single auxiliary guide bar, proceed to S2:

[0060] The real-time current I of the reference conductor is obtained using a current sensor. ref (t), Real-time current I of the auxiliary conductor aux (t);

[0061] Establish the rotor current space vector in the reference guide bar coordinate system Where, k w This is the equivalent coefficient for rotor current reduction.

[0062] The selection and arrangement of the current sensor mentioned above will be further described in the subsequent Embodiment 2, and will not be elaborated here.

[0063] S3, Extract the space vector of the rotor fundamental current in the reference conductor coordinate system.

[0064] The purpose of S3 is to eliminate the influence of rotor current space vector harmonics on magnetic field position estimation. See also Figure 3 , Figure 3 That is, the space vector of the rotor fundamental current. The extraction flowchart shows that LPF is a low-pass filter used to filter out high frequencies.

[0065] Specifically, S3 includes:

[0066] S301, Obtain the real-time induction motor slip ω under steady-state conditions. f (t), through integration operation ∫ω f (t)dt yields the slip space angle.

[0067] Among them, the slip ω of the induction motor f(t) represents the difference between the stator magnetic field rotational angular velocity and the rotor rotational angular velocity; the stator magnetic field rotational angular velocity is obtained based on the three-phase stator current frequency calculated by the motor controller, and the rotor rotational angular velocity is obtained based on the position sensor decoding by the motor controller.

[0068] S302, regarding the rotor current space vector in the reference conductor coordinate system. Perform spatial angle as The vector transformation yields the transformed current vector.

[0069] S303, for the transformed current vector The real and imaginary parts are filtered separately, and the filtered signal is then subjected to a spatial angle of... The vector transformation yields the rotor fundamental current space vector. The filtering process can be performed using a low-pass filter.

[0070] S4, Calculate the spatial vector position θ of the rotor fundamental current in the stator coordinate system. ir (t).

[0071] The stator coordinate system is based on the direction of the stator A-phase winding as the abscissa, leading the spatial angle of the A-phase winding. The vertical axis is a rectangular coordinate system. The purpose of S4 is to obtain the real-time position θ of the rotor current space vector in the stator coordinate system. ir (t), which is the angle relative to the stator A-axis.

[0072] Specifically, S4 includes:

[0073] S401, obtain the real-time spatial position of the reference guide bar relative to the stator A-axis, denoted as θ0(t);

[0074] θ0(t) can be obtained using the position / speed sensor built into the motor controller.

[0075] S402, Calculate the rotor fundamental current space vector Angle Let it be θ1(t);

[0076] See Figure 2 , The calculation is based on the rotor fundamental current space vector. The real and imaginary parts are obtained using inverse trigonometric functions. For example, the tangent value is calculated based on the real and imaginary parts, where tangent = imaginary part / real part, and then obtained through the arctangent. Of course, the sine value can also be calculated based on the real and imaginary parts. Then obtain it through the arcsine.

[0077] S403, Calculate the rotor fundamental current space vector The real-time position θ in the stator coordinate system ir (t), where θ ir (t)=θ0(t)+θ1(t).

[0078] S5, Determine the real-time position θ of the rotor magnetic field in the stator coordinate system. M (t).

[0079] S5 utilizes the M-axis current component i in the rotor magnetic field direction under steady state. rm The property that (t) is 0 means that θ in S4 ir (t) represents the direction of the leading or lagging rotor magnetic field. T-axis current component i rt (t) Real-time location.

[0080] Based on the sign relationship of the T-axis current component under two operating conditions—motor drive (outputting positive torque) and generator (outputting negative torque)—the real-time position of the rotor magnetic field can be expressed as:

[0081] (a) Under positive torque output conditions, the real-time position of the rotor magnetic field is:

[0082] (b) Under negative torque output conditions, the real-time position of the rotor magnetic field is:

[0083] Example 2

[0084] This embodiment provides an induction motor rotor magnetic field position measuring device, which uses the induction motor rotor magnetic field position measuring method of Embodiment 1. The rotor magnetic field position measuring method will not be described in detail here.

[0085] See Figure 4 The rotor magnetic field position measuring device includes a sensor module, a signal transmission module, and a signal calculation module. The sensor module acquires the real-time current of the reference and auxiliary conductors. The signal transmission module transmits the signals from the sensor module. The signal calculation module receives the signals transmitted from the signal transmission module, as well as the slip and reference conductor position signals calculated by the motor controller, and calculates the real-time rotor magnetic field position.

[0086] For the sensor module, after determining the positions of the reference and auxiliary conductors as described in Example 1, Rogowski coils or Hall effect current sensors are arranged on the conductors to convert the real-time rotor conductor current into an analog electrical signal. It is important to note that the sensor parameters and arrangement must fully consider performance indicators such as conductor current range, conductor temperature, and rotational balance.

[0087] Of course, see Figure 5The sensor module is not limited to current sensors; it can also integrate thermistor temperature sensors to convert the real-time temperature of the rotor bars into analog electrical signals, which facilitates the expansion of other functions. Further details will not be provided here.

[0088] Depending on the application requirements, signal transmission methods can be divided into two types: brush type and telemetry type. The signal transmission modules and signal calculation modules of the two transmission methods are different.

[0089] (a) Signal transmission module using brush type

[0090] See Figure 6 The signal transmission module includes multiple brush rings. These brush rings are positioned on the outer ring of the motor rotor and rotate synchronously with it. The power supply and signal lines of the sensor module are fixedly connected to the inner side of the brush rings, while the outer side of the brush rings transmits analog electrical signals to the signal calculation module.

[0091] The signal calculation module includes a power conversion circuit, a signal processing circuit, a signal communication circuit, and a microcontroller. The power conversion circuit converts the external input power into different voltage levels to power the microcontroller, signal processing circuit, signal communication circuit, and sensor module. The signal processing circuit converts, amplifies, or performs anti-interference processing on analog electrical signals. The microcontroller uses the rotor magnetic field position measurement method of Example 1 to calculate the real-time position of the rotor magnetic field and encodes the calculation results according to a high-speed communication protocol. The signal communication circuit acquires the real-time position of the rotor magnetic field and outputs the encoded result signal in real time.

[0092] The external input power supply mentioned in this design is generally a 12V DC power supply. After passing through the power conversion circuit, the 12V DC power supply powers the sensor module and other processing circuits.

[0093] (ii) Using a telemetry signal transmission module

[0094] See Figure 7 The signal transmission module is mounted on the motor rotor and rotates synchronously with it. The signal transmission module includes a built-in power supply, signal processing circuitry, and wireless transmission circuitry. The built-in power supply is either a synchronously rotating battery or wireless power transmission. The signal processing circuitry is used to convert, amplify, or perform anti-interference processing on the analog electrical signals. The wireless transmission circuitry is used to send the processed analog electrical signals to the signal calculation module via a transmission protocol.

[0095] The signal calculation module includes a power conversion circuit, a wireless receiving circuit, a signal communication circuit, and a microcontroller. The power conversion circuit converts the external input power into different voltage levels to power the microcontroller, signal processing circuit, signal communication circuit, and wireless receiving circuit. The wireless receiving circuit receives the processed analog electrical signals in real time. The microcontroller calculates the real-time position of the rotor magnetic field using the rotor magnetic field position measurement method of Example 1 and encodes the calculation results according to a high-speed communication protocol. The signal communication circuit acquires the real-time position of the rotor magnetic field and outputs the encoded result signal in real time.

[0096] In this design, the external input power supply is a 12V DC power supply, which is a separate component from the built-in power supply. The built-in power supply rotates synchronously with the motor rotor.

[0097] Based on the above measuring device, the position of the rotor magnetic field of the induction motor can be measured. (See also...) Figure 8 1) During the development stage of the induction motor control system, the method / device of this invention can be used to modify the induction motor test prototype to achieve real-time measurement of the rotor magnetic field position, thereby completing the accurate measurement of motor parameters at different operating points, evaluation and improvement of rotor magnetic field position estimation schemes, and improvement of other control software performance; 2) During the product application stage, the optimized control software can be deployed to the mass-produced induction motor drive system to improve the performance of the induction motor.

[0098] Example 3

[0099] As mentioned in the background section, motor parameter calibration and rotor magnetic field position are interrelated, such as... Figure 9 As shown.

[0100] This embodiment provides an application of the rotor magnetic field position measurement method of Embodiment 1, specifically for acquiring induction motor control parameters. This application is based on finite element simulation. It is essentially equivalent to the actual induction motor parameter calibration method based on the measuring device of Embodiment 2. See also... Figure 10 The specific steps include:

[0101] Step 1: Determine the steady-state finite element simulation operating point of the induction motor, including but not limited to the stator current amplitude I. s Stator current frequency ω s Rotor electrical frequency ω r Combination of three state variables (I) s ,ω s ,ω r ).

[0102] The finite element simulation uses electromagnetic simulation software, including Maxwell and JMAG. An induction motor finite element model is selected as the basis for the simulation model, and the state variable combination (I0) is defined.s ,ω s ,ω r The value of ).

[0103] Step 2: Extract electromagnetic quantity simulation results. Using finite element simulation, extract different electromagnetic quantities in the stator coordinate system under steady-state conditions, including but not limited to the three-phase stator flux linkage. Three-phase stator current Reference and auxiliary conductor currents, three-phase stator inductance parameter matrix

[0104] The currents of the reference and auxiliary conductors can be directly obtained using a field calculator.

[0105] Step 3: Calculate the real-time position of the rotor magnetic field in the stator coordinate system. Based on the rotor magnetic field position measurement method of Example 1, the real-time position θ of the rotor magnetic field in the stator coordinate system is calculated. M (t); This will not be repeated here.

[0106] Step 4: Calculate the control parameters under rotor magnetic field orientation. Electromagnetic quantities in the rotor magnetic field coordinate system are calculated using coordinate transformation. The coordinate transformation matrix is ​​introduced, as shown in equation (1):

[0107]

[0108] Ignoring the cross-coupling between the M and T axes, the stator flux linkage in the rotor coordinate system Stator current Stator inductor The following formulas (2), (3), and (4) can be used to obtain:

[0109]

[0110]

[0111]

[0112] Among them, stator inductor Including stator M-axis self-inductance Stator T-axis self-inductance

[0113] The rotor time constant T is obtained using equation (5). r :

[0114]

[0115] The rotor equivalent current in the rotor coordinate system is calculated using winding reduction and coordinate transformation. and utilize formula Obtaining mutual inductance between stator and rotor

[0116]

[0117] Based on the fact that the rotor flux linkage component on the T-axis is 0, the equivalent self-inductance flux linkage of the rotor on the T-axis is calculated according to equation (7).

[0118]

[0119] Of course, by changing the simulation operating point of the induction motor and repeating steps one to four above, the motor control parameters at different operating points can be obtained. The obtained parameters can be used for controller design and simulation model construction.

[0120] The following uses a finite element model of a certain automotive induction motor as an example to implement the above-mentioned rotor magnetic field position calculation method and motor parameter acquisition method, with a simulation performed using a single operating point as an example.

[0121] The working point O selected in this example is: (I s =50A,ω s =314 rad / s, ω r =289 rad / s).

[0122] See Figure 11 This is a finite element simulation model of a two-pair squirrel-cage induction motor. The selected positions of the reference conductor and auxiliary conductor bars are as follows: Figure 11 As shown in the image.

[0123] Based on the above methods for calculating the rotor magnetic field position and obtaining motor parameters, the results are as follows: Figure 12 , Figure 13 , Figure 14 And Table 1.

[0124] in, Figure 12 From top to bottom: reference conductor and auxiliary conductor current, rotor current space vector in reference conductor coordinate system, and rotor current space vector in reference conductor coordinate system after harmonic removal. Figure 13 The rotor magnetic field position in the stator coordinate system is determined based on the rotor current vector and the rotor spatial position. Figure 14 From top to bottom, they are: MT-shaft stator current in rotor magnetic field coordinate system, MT-shaft stator flux linkage in rotor magnetic field coordinate system, and MT-shaft stator self-inductance in rotor magnetic field coordinate system.

[0125] Considering that the parameters are basically constant in steady state under the rotor field-oriented MT coordinate system, the parameters are averaged in the time domain, and the final control parameters are shown in Table 1:

[0126] Table 1. Results of induction motor parameter acquisition at operating point O

[0127]

[0128] Example 4

[0129] This embodiment also discloses a readable storage medium storing computer program instructions. When the computer program instructions are read and executed by a processor, the above-described method for measuring the position of the rotor magnetic field of an induction motor is performed.

[0130] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method of measuring the position of the magnetic field of a rotor of an induction motor, characterized in that, The method comprises the following steps: S1, determining a reference bar and an auxiliary bar on the rotor side; Wherein, S1 comprises: selecting one bar of the rotor as the reference bar, and then determining the auxiliary bar based on the reference bar; S2, establish the rotor current space vector in the reference guide bar coordinate system ; wherein, t characterization time; The reference guide bar coordinate system is a coordinate system with the reference guide bar spatial position as the horizontal coordinate axis and the leading reference guide bar spatial electric angle as the vertical coordinate axis. The reference guide bar coordinate system is a coordinate system with the reference guide bar spatial position as the horizontal coordinate axis and the leading reference guide bar spatial electric angle as the vertical coordinate axis. S3, extracting the rotor fundamental current space vector in the reference guide bar coordinate system S3 includes: S301, obtaining real-time slip of induction motor under steady state working condition , obtaining slip space angle by integral operation ;​ S302, the rotor current space vector in the reference guide bar coordinate system is subjected to vector transformation with a spatial angle of to obtain the transformed current vector ; S303, for the transformed current vector The real and imaginary parts are filtered separately, and the filtered signal is then subjected to a spatial angle of... The vector transformation yields the rotor fundamental current space vector. ; S4, calculating the position of the rotor fundamental current space vector in the stator coordinate system ; S5, determining real-time position of the rotor magnetic field in the stator coordinate system ; Wherein, if in the motor output positive torque working condition, the rotor magnetic field real-time position is ; If the motor output negative torque condition, the rotor magnetic field real-time position is: .

2. The method of claim 1, wherein The determination method of the auxiliary bar in S1 is: Taking counterclockwise as the positive direction, select the spatial electrical angle of the leading reference conductor. The two guide bars that are symmetrically mirrored in position serve as auxiliary guide bars and form an auxiliary guide bar pair.

3. The method of claim 1, wherein The determination method of the auxiliary bar in S1 is: When the number of phases of the induction motor rotor is a multiple of 4 m , the bar with the leading reference bar space angle in the counterclockwise positive direction is selected as the auxiliary bar. ​ 4. The method of claim 2, wherein S2 It comprises: acquiring real-time currents of the reference guide bar , real-time currents of two auxiliary guide bars , ; Converting the real-time currents of the two auxiliary bars , to equivalent auxiliary bar current values wherein , is the difference in the spatial electrical angle between the pair of auxiliary bars; Establishing a rotor current space vector in a reference guide bar coordinate system wherein, is a rotor current reduction equivalent coefficient.

5. The method of claim 3, wherein S2 It comprises: acquiring a real-time current of the reference guide bar , a real-time current of the auxiliary guide bar ; Establishing a rotor current space vector in a reference guide bar coordinate system wherein, is a rotor current reduction equivalent coefficient.

6. The method for measuring the magnetic field position of an induction motor rotor according to claim 5, characterized in that S4 It uses the induction motor rotor magnetic field position measurement method as claimed in any one of claims 1-6; S401, acquiring real-time space position of the reference guide bar relative to the stator A axis, denoted as ; S402, calculate the rotor fundamental current space vector of the angle , denoted as ; S403, calculate the rotor fundamental current space vector at the real-time position of the stator coordinate system wherein .

7. A device for measuring the position of the magnetic field of a rotor of an induction motor, characterized in that The rotor magnetic field position measurement device comprises: A sensor module for acquiring real-time currents of the reference bar and the auxiliary bar; A signal transmission module for transmitting signals of the sensor module; and A signal calculation module for receiving the transmitted signals of the signal transmission module and the slip and the reference bar position signals calculated by the motor controller, and calculating the real-time position of the rotor magnetic field. The induction motor rotor magnetic field position measurement method is applied to acquire control parameters of the induction motor.

8. Use of the method of measuring the position of the magnetic field of the rotor of an induction motor according to any one of claims 1 to 6, characterized in that, The steady-state finite element simulation working point of the induction motor is determined, the electromagnetic simulation results are extracted, the real-time position of the rotor magnetic field in the stator coordinate system is calculated, and the control parameters under the rotor magnetic field orientation are calculated.

9. The use of the method for measuring the position of the magnetic field of the rotor of an induction motor according to claim 8, characterised in that, ​

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