Method, device and motor for calculating instantaneous value of armature reaction inductance

Abstract

The present application discloses a method, device and motor for calculating the instantaneous value of armature reaction inductance, and relates to the technical field of motors. The method for calculating the instantaneous value of armature reaction inductance includes: obtaining the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor; calculating the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the mechanical angle of the rotor of the motor and the preset calculation model. It can be seen that the method can directly calculate the instantaneous value of the armature reaction inductance by establishing a calculation model and only needing to obtain the instantaneous value of the current and the mechanical angle of the rotor of the motor. The method can take into account the influence of the motor rotor position and the current phase on the armature reaction inductance, is simple and reliable, does not require coordinate transformation, and will not affect the information of the original data, that is, it will not cause the information of the original data to be lost.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a method and device for calculating the instantaneous value of armature reaction inductance, and a motor. Background Art

[0002] When studying the control strategy and evaluating the control effect of permanent magnet synchronous motors, the real-time feedback of the instantaneous values ​​of the parameters of the controlled motor (such as the instantaneous value of the armature reaction inductance) is of great reference significance to developers. The traditional method is to transform the various electrical quantities of the motor into dq0 coordinates and decompose them into direct-axis components and quadrature-axis components that rotate synchronously with the motor rotor, thereby reducing the complexity of control. However, a lot of useful information in the original data is also lost, which is not conducive to the analysis of certain transient problems. Summary of the invention

[0003] Purpose of the invention: An embodiment of the present application provides a method for calculating the instantaneous value of armature reaction inductance, aiming to overcome the technical problem of loss of original data in the calculation of the instantaneous value of armature reaction inductance in the prior art; another purpose of an embodiment of the present application is to provide a device for calculating the instantaneous value of armature reaction inductance; the third purpose of the present application is to provide a motor.

[0004] Technical solution: A method for calculating the instantaneous value of armature reaction inductance described in an embodiment of the present application includes:

[0005] Obtain the instantaneous value of the motor current and the mechanical angle of the motor rotor;

[0006] The instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and a preset measurement model.

[0007] In some embodiments, the instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor, and a preset measurement model, including:

[0008] Determining a rotor electrical angle according to a rotor mechanical angle of the motor;

[0009] Determining the phase angle of the current lagging back electromotive force according to the instantaneous value of the current of the motor and the electrical angle of the rotor;

[0010] The instantaneous value of the armature reaction inductance is calculated based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and the preset measurement model.

[0011] In some embodiments, the calculation formula of the preset calculation model is:

[0012]

[0013] Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back electromotive force; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor.

[0014] In some embodiments, determining the rotor electrical angle according to the rotor mechanical angle includes:

[0015] Get the number of motor pole pairs;

[0016] The rotor electrical angle is determined according to the rotor mechanical angle and the number of motor pole pairs.

[0017] In some embodiments, determining the phase angle of the current lagging back electromotive force according to the instantaneous current value and the rotor electrical angle includes:

[0018] Analyzing and obtaining the current phase angle according to the instantaneous value of the current;

[0019] The phase angle of the current lagging the back electromotive force is determined according to the current phase angle, the rotor electrical angle, and the corresponding relationship between the back electromotive force and the rotor electrical angle.

[0020] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase b is:

[0021]

[0022] Among them, L bs (θ e ,γ) is the instantaneous value of the armature reaction inductance of motor phase b.

[0023] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase c is:

[0024]

[0025] Among them, L cs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase c of the motor.

[0026] Accordingly, a device for calculating the instantaneous value of armature reaction inductance described in an embodiment of the present application includes: a current detection module, a rotor angle detection module and a control module; the current detection module is used to detect the instantaneous value of the current of the motor and send it to the control module; the rotor angle detection module is used to detect the rotor mechanical angle of the motor and send it to the control module;

[0027] The control module is used to: obtain the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor;

[0028] The instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and a preset measurement model.

[0029] In some embodiments, the control module is further used to: determine a rotor electrical angle according to a rotor mechanical angle of the motor;

[0030] Determining the phase angle of the current lagging back electromotive force according to the instantaneous value of the current of the motor and the electrical angle of the rotor;

[0031] The instantaneous value of the armature reaction inductance is calculated based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and the preset measurement model.

[0032] In some embodiments, the calculation formula of the preset calculation model is:

[0033]

[0034] Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back electromotive force; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor.

[0035] In some embodiments, the current detection module is a current sensor, and the rotor angle detection module is a rotor angle position sensor.

[0036] Correspondingly, an embodiment of the present application describes a motor, which includes a variable frequency drive and a device for measuring the instantaneous value of the armature reaction inductance as described above.

[0037] Beneficial effect: Compared with the prior art, the instantaneous value of the armature reaction inductance of the embodiment of the present application is calculated by the method, device and motor, and the instantaneous value of the armature reaction inductance includes: obtaining the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor; calculating the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the mechanical angle of the rotor of the motor and the preset calculation model. It can be seen that the method can directly calculate the instantaneous value of the armature reaction inductance by establishing a calculation model and only needs to obtain the instantaneous value of the current and the mechanical angle of the rotor of the motor. The method can take into account the influence of the motor rotor position and the current phase on the armature reaction inductance, is simple and reliable, does not require coordinate transformation, and does not affect the information of the original data, that is, it does not cause the information of the original data to be lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 is a flow chart of a method for calculating the instantaneous value of armature reaction inductance provided in an embodiment of the present application;

[0040] Figure 2 is a structural schematic diagram of an idealized three-phase synchronous motor provided in an embodiment of the present application;

[0041] Figure 3 It is a schematic diagram of the overall process of a method for calculating the instantaneous value of armature reaction inductance provided in an embodiment of the present application;

[0042] Figure 4 A principle structure block diagram of a device for measuring the instantaneous value of armature reaction inductance provided in an embodiment of the present application;

[0043] Figure 5 It is a structural schematic diagram of a motor test system provided in an embodiment of the present application.

[0044] Reference numerals:

[0045] 100-motor; 101-frequency converter; 102-parameter measurement controller; 103-current sensor; 104-rotor angle position sensor; 10-current detection module; 20-rotor angle detection module; 30-control module. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0047] It should be understood that although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0048] Those skilled in the art will appreciate that the drawings are only schematic diagrams of example embodiments and may not be to scale. The modules or processes in the drawings are not necessarily required to implement the present application and therefore cannot be used to limit the scope of protection of the present application.

[0049] The applicant has found that the permanent magnet synchronous motor uses a permanent magnet rotor, has the advantages of high power density and no rotor copper loss, and is widely used in new energy vehicles, variable speed power generation and other fields. As energy utilization efficiency is increasingly valued, the installed capacity of permanent magnet synchronous motors continues to grow, and the application field is also expanding. However, the advantages of permanent magnet synchronous motors are not achieved without a price. Unlike wound rotor synchronous motors, the rotor excitation of permanent magnet motors is fixed and cannot be adjusted as needed, which brings many challenges to control; and the performance of permanent magnets is related to temperature. When the motor is running and heating, the corresponding reduction in induced potential must be considered. The induced potential caused by the magnetic field of the permanent magnet rotor in the armature winding can generally be obtained through an open circuit test of the motor armature winding, but it is difficult to measure directly when the motor is loaded, and it needs to be estimated by the back electromotive force coefficient, or calculated by the armature current, armature terminal voltage, winding ohmic voltage drop, armature reaction voltage, etc. Among them, the armature current and terminal voltage can be directly measured, the winding ohmic voltage drop can be calculated by the winding AC resistance, and the armature reaction voltage is related to the armature reaction inductance. For multi-phase AC synchronous motors, the armature reaction voltage of one phase winding is related to the current and inductance of each phase winding of the armature. For permanent magnet synchronous motors without salient pole ratio, the armature reaction inductance is basically constant, and the instantaneous value is basically unchanged; while for permanent magnet synchronous motors with salient pole ratio, the armature reaction inductance is not only related to the rotor angle, but also to the load state of the motor, and further, to the phase angle of the current, and its value changes in real time with the load change.

[0050] When conducting control strategy research and control effect evaluation of permanent magnet synchronous motors, real-time feedback of the instantaneous values ​​of various parameters of the controlled motor is of great reference significance to developers. The traditional method is to transform the various electrical quantities of the motor into dq0 coordinates and decompose them into direct-axis components and quadrature-axis components that rotate synchronously with the motor rotor, thereby reducing the complexity of control, but at the same time also losing a lot of useful information in the original data, which is not conducive to the analysis of certain transient problems.

[0051] To this end, an embodiment of the present application provides a method for calculating the instantaneous value of the armature reaction inductance, so as to realize the calculation of the instantaneous value of the armature reaction inductance of each phase of the motor without the need for operations such as coordinate transformation. It is simple and reliable and will not cause the loss of original data information.

[0052] Figure 1 It is a flow chart of a method for calculating the instantaneous value of armature reaction inductance provided in an embodiment of the present application. This method studies the measurement technology of the instantaneous value of armature reaction inductance for the armature reaction of a permanent magnet synchronous motor, solves the problem of observing the instantaneous value and change law of part of the electrical quantity when conducting relevant research on the control of a permanent magnet synchronous motor, and provides a more intuitive real-time feedback signal for control strategy research and control effect evaluation. This method can be applied to the process of calculating the instantaneous value of the armature reaction inductance of each phase of the motor during the application of the motor. This method can be executed by a device for measuring the instantaneous value of the armature reaction inductance, which can be implemented by software and / or hardware, and can be configured in the controller of the motor. Please refer to Figure 1 , the method comprises the following steps:

[0053] Step 110: Obtain the instantaneous value of the motor current and the rotor mechanical angle of the motor.

[0054] The instantaneous value of the current of the motor can be obtained by detecting a current detection device, such as a current sensor, etc. The mechanical angle of the rotor of the motor can be obtained by detecting a rotor angle detection device, such as a rotor angle position sensor. The motor can be a permanent magnet synchronous three-phase motor.

[0055] Step 120 , calculating the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor, and a preset measurement model.

[0056] The preset direct-axis inductance of the motor and the preset quadrature-axis inductance of the motor can be obtained from the factory data of the motor.

[0057] Specifically, by pre-constructing a calculation model for the instantaneous value of the armature reaction inductance, and taking the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, and the rotor mechanical angle of the motor as inputs of the calculation model, the instantaneous value of the armature reaction inductance of each phase of the motor can be calculated. In this way, the instantaneous value of the armature reaction inductance of each phase of the motor can be calculated in real time, which is convenient for the subsequent transient analysis of each phase of the motor, and does not require coordinate transformation, and will not cause the loss of original data. In addition, in the calculation process, the influence of the motor rotor position and current phase on the armature reaction inductance is fully considered, thereby improving the accuracy of the calculation.

[0058] In the technical solution of this embodiment, the working principle of the method for calculating the instantaneous value of the armature reaction inductance is as follows: Figure 1 First, the instantaneous value of the motor current and the mechanical angle of the motor rotor are obtained. Then, the instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the motor current, the mechanical angle of the motor rotor and the preset measurement model. It can be seen that this method can directly calculate the instantaneous value of the armature reaction inductance by establishing a measurement model and only needing to obtain the instantaneous value of the motor current and the mechanical angle of the rotor. This method can take into account the influence of the motor rotor position and current phase on the armature reaction inductance, is simple and reliable, does not require coordinate transformation, and will not affect the information of the original data, that is, it will not cause the information of the original data to be lost.

[0059] In some embodiments, the instantaneous value of the armature reaction inductance is calculated based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the mechanical angle of the rotor of the motor, and a preset measurement model, including: determining the rotor electrical angle based on the mechanical angle of the rotor of the motor; determining the phase angle of the current lagging back electromotive force based on the instantaneous value of the current of the motor and the rotor electrical angle; calculating the instantaneous value of the armature reaction inductance based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and a preset measurement model.

[0060] Specifically, first, the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor are obtained. Then, the rotor electrical angle is obtained according to the mechanical angle of the rotor of the motor, and the phase angle of the current lag back electromotive force is determined according to the instantaneous value of the current of the motor and the rotor electrical angle. Finally, the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle and the phase angle of the current lag back electromotive force are used as inputs of the measurement model, and are input into the measurement model to calculate the instantaneous value of the armature reaction inductance. It can be seen that when the instantaneous value of the armature reaction inductance of each phase of the motor is calculated in real time, it is only necessary to obtain the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor in real time, and input the obtained value as an input into the preset measurement model for calculation, so as to obtain the instantaneous value of the armature reaction inductance of each phase of the motor. The method is simple and easy to implement, and does not require coordinate transformation, so that the original data will not lose information. And the influence of the motor rotor position and the current phase on the armature reaction inductance is fully considered during the measurement, so as to provide the measurement accuracy of the instantaneous value of the armature reaction inductance of each phase of the motor.

[0061] In some embodiments, the calculation formula of the preset calculation model is:

[0062]

[0063] Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back EMF; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor. Among them, the preset direct-axis inductance and the preset quadrature-axis inductance of the motor can be obtained from the factory data of the motor.

[0064] For example, in the technical solution of the embodiment of the present application, a three-phase motor is used as an example for explanation (the same below, no further description is given). After obtaining the rotor electrical angle of the motor, the phase angle of the current lagging back electromotive force, the preset direct-axis inductance of the motor, and the preset quadrature-axis inductance of the motor, the instantaneous value of the armature reaction inductance of the motor phase a can be directly calculated according to the above calculation formula.

[0065] Figure 2 is a schematic diagram of the structure of an idealized three-phase synchronous motor provided in an embodiment of the present application. Figure 2 , the inductance of the three-phase synchronous motor is introduced as follows:

[0066] For the purpose of this analysis, we assume Figure 2 The synchronous motor meets the following two conditions:

[0067] First, the air gap permeance has a constant component and a smaller component that varies with the cosine of twice the rotor angle (electrical angle). The rotor angle is referenced to the direct axis and the stator a-phase axis. The electrical angle θ e for:

[0068]

[0069] Among them, poles represents the number of motor poles.

[0070] Second, the influence of space harmonics in the air gap flux can be ignored.

[0071] Based on the above two conditions, the rotor electrical angle θ e Write down the expressions for the various inductances of the motor. They are as follows:

[0072] The self-inductance of the stator winding is:

[0073]

[0074] Among them, the mutual inductance between stator windings is:

[0075]

[0076] Wherein, the subscripts a, b, and c represent phase a, phase b, and phase c respectively. ζ represents inductance. If the subscripts are the same, it is the self-inductance of the winding. If the subscripts are different, it is the mutual inductance between the windings. L al is the leakage inductance of phase a winding, L aao is the inductance of phase a corresponding to the constant component of air gap permeance. The three phases are symmetrical. The winding leakage inductance of phases a, b, and c is the same as the constant component of air gap permeance, indicated by the same subscript; L g2 is the amplitude of the inductance corresponding to the component of the air gap permeability that varies with the rotor position angle.

[0077] The effect of salient poles only appears in the stator self-inductance and mutual inductance terms, which is a function of 2θ e This two-fold angle change can be referred to Figure 2 To understand, this figure is a simplified diagram of a salient pole synchronous motor with rotor winding. Figure 2 It can be seen that the original structure of the magnetic circuit is reproduced when the rotor rotates through 180 degrees.

[0078] The relationship between armature reaction voltage and equivalent armature reaction inductance is derived as follows:

[0079] According to the law of electromagnetic induction, the voltage component of the armature winding of a three-phase motor caused by the armature reaction, that is, the component related to the armature current, is:

[0080]

[0081] Among them, ia (t), i b (t) and i c (t) represents the armature current of phases a, b, and c respectively, and e as (t), e bs (t), e cs (t) represents the voltage components of phases a, b, and c due to armature reaction.

[0082] Express (Equation 3) in matrix form, that is:

[0083]

[0084] When a three-phase motor operates normally, the three-phase current amplitudes are equal and the phase difference is 120 degrees. If the current expression of any one phase is known, the current expressions of the other two phases can be obtained based on the relationship between the three-phase currents.

[0085] Therefore, the armature reaction voltage component of each phase can be expressed by the current of the corresponding phase, that is,

[0086]

[0087] Among them, as (t), ζ bs (t), ζ cs (t) represents the equivalent armature reaction inductance of each phase of armature winding a, b, and c. Therefore,

[0088]

[0089] According to the expressions of the self-inductance of the stator winding and the mutual inductance between windings (Equation 1) and (Equation 2), it can be known that:

[0090] By using matrix operations and extracting the same variables, the above formula can be simplified to the following form:

[0091]

[0092] According to the relationship between back electromotive force and rotor angle, the three-phase current expression is derived as follows:

[0093] like Figure 2 , the rotor magnetic field B of the three-phase synchronous motor R The moment when the direction of the a-phase axis is consistent is the time starting point, and the rotor magnetic field B R With electrical angular velocity ω e (t) is rotating in the positive direction. Then:

[0094] ∫ω e (t)dt=θ e

[0095] When the three-phase synchronous motor runs stably at the synchronous speed, ω e (t) = ω e is a constant value, the above formula can be simplified to:

[0096] ω e t=θ e

[0097] According to the principle of the motor, the back electromotive force in each phase winding is in the rotor magnetic field B R The peak value is obtained when the corresponding winding is swept, such as Figure 2 , the positions of the windings of phases a, b, and c are 90 degrees, (120+90) degrees, and (240+90) degrees away from the 0 degree position corresponding to the time starting point, respectively, so the back electromotive force of phases a, b, and c can be expressed as:

[0098]

[0099] Assume that the three-phase synchronous motor is running at synchronous speed ω e (t) = ω e During stable operation, the phase of the a-phase winding current lags behind the rotor magnetic field, and the electrical angle of the induced voltage in the a-phase winding is γ, then:

[0100]

[0101] That is, the three-phase current expression is:

[0102]

[0103] Among them, I max Indicates the current amplitude.

[0104] Therefore, by substituting (Equation 6) and (Equation 7) into (Equation 5), we can obtain:

[0105]

[0106] Since the motor is operating normally, i a (t)+i b (t)+i c (t) = 0, so and will Substitute it into the formula, and we get

[0107] The trigonometric function part in the above formula can be simplified, let θ e -γ=δ, then

[0108] so:

[0109]

[0110] because

[0111] When sin(θ e -γ)≠0, i.e. i a When (t)≠0,

[0112] When sin(θ e -γ-120°)≠0, i.e. i b When (t)≠0,

[0113] When sin(θ e -γ-240°)≠0, i.e. i c When (t)≠0,

[0114] so,

[0115]

[0116] Right now

[0117]

[0118] so

[0119]

[0120] According to the principle of electromechanics,

[0121]

[0122] Among them, L d and L q There are direct-axis inductance and quadrature-axis inductance, which can be obtained from the factory data of the synchronous motor.

[0123] By replacing the parameters of the armature reaction inductance expression, we can get:

[0124]

[0125] When the phase current is 0, that is, the denominator of the trigonometric function in the expression is 0, the expression of the equivalent armature reaction inductance of the corresponding phase is meaningless. The domain of the function expression can be determined by the natural domain. Therefore, in the end, the equivalent armature reaction inductance of each phase a, b, and c of the three-phase motor is about the quadrature axis inductance L q , direct axis inductance L d 、Electrical angle θ e The expression of the current lag back EMF angle γ can be written as:

[0126]

[0127] In some embodiments, determining the rotor electrical angle according to the rotor mechanical angle includes: obtaining the number of motor pole pairs; and determining the rotor electrical angle according to the rotor mechanical angle and the number of motor pole pairs.

[0128] The number of motor pole pairs may be determined based on specific motor factory information (such as a motor manual or data sheet), and may be set based on actual conditions, and is not specifically limited here.

[0129] Specifically, after the number of motor pole pairs and the rotor mechanical angle are obtained, the rotor electrical angle may be calculated based on the product of the number of motor pole pairs and the rotor mechanical angle.

[0130] In some embodiments, the phase angle of the current lagging back EMF is determined based on the instantaneous value of the current and the rotor electrical angle, including: obtaining the current phase angle based on the instantaneous value of the current; and determining the phase angle of the current lagging back EMF based on the current phase angle, the rotor electrical angle, and the corresponding relationship between the back EMF and the rotor electrical angle.

[0131] Among them, the corresponding relationship between the back electromotive force and the rotor electrical angle can be determined through theoretical analysis, numerical simulation, data analysis and fitting, etc., and can be determined by referring to the existing technical solutions. No specific limitation or detailed explanation is made here.

[0132] Among them, when the rotor pole sweeps across the average position of the armature winding, the back electromotive force reaches its peak value.

[0133] Specifically, after obtaining the instantaneous current value and the rotor mechanical angle of the motor, the current phase angle is obtained by analyzing the instantaneous current value. The rotor electrical angle can be obtained according to the rotor mechanical angle and the number of motor pole pairs. Finally, the phase angle of the current lagging back EMF can be calculated based on the current phase angle, the rotor electrical angle, and the corresponding relationship between the preset back EMF and the rotor electrical angle.

[0134] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase b is:

[0135]

[0136] Among them, L bs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase b of the motor.

[0137] Specifically, when the three-phase permanent magnet synchronous motor is loaded, the armature reaction voltage in phase a is proportional to the rate of change of the flux of the phase a winding turn chain, and the instantaneous value of the phase a flux depends on the current and self-inductance of phase a, the current of phase b and its mutual inductance with phase a, and the current of phase c and its mutual inductance with phase a. Based on the premise of multi-phase symmetry, the armature reactions of the remaining phases can be reduced to the same phase for analysis. Due to the three-phase symmetry of the three-phase motor, the instantaneous value of the phase a flux can be equivalently transformed into the product of the current of phase a and the equivalent armature reaction inductance, and the equivalent armature reaction inductance calculation formula and algorithm can be calculated according to the calculation formula of the above-mentioned preset measurement model. Therefore, in order to calculate the armature reaction voltage in real time, it is only necessary to measure the equivalent armature reaction inductance value in real time.

[0138] For the equivalent armature reaction inductance of phases b and c, due to the three-phase symmetry, it is necessary to replace the θ in the calculation formula of the equivalent armature reaction inductance of phase a with e Replace them with (θ e -120°) and (θ e -240°).

[0139] When sin(θ e -γ)=0, the instantaneous value of phase a current is zero, and the equivalent armature reaction inductance value of phase a is meaningless.

[0140] When sin(θ e When -120°-γ)=0, the instantaneous value of the b-phase current is zero, and the equivalent armature reaction inductance value of the b-phase is meaningless.

[0141] When sin(θ e When -240°-γ)=0, the instantaneous value of the c-phase current is zero, and the equivalent armature reaction inductance value of the c-phase is meaningless.

[0142] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase c is:

[0143]

[0144] Among them, L cs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase c of the motor.

[0145] It can be seen that the embodiment of the present application provides a method for calculating the instantaneous value of the armature reaction inductance for a permanent magnet synchronous motor operating under different load conditions, from which the instantaneous values ​​and change laws of other armature reaction related parameters can be deduced. This method can realize independent measurement of the instantaneous value of the armature reaction inductance of each phase of the motor without coordinate transformation, and can measure the instantaneous value of the armature reaction inductance in real time, which is convenient for transient analysis of single-phase electrical quantity. And the influence of the motor rotor position and current phase on the armature reaction inductance is taken into account. This method is suitable for occasions where there is a need to observe the change law of the instantaneous value of the three-phase armature reaction inductance, which is conducive to data analysis of permanent magnet synchronous motor control related experiments and verification of motor control algorithms.

[0146] Compared with the prior art, when analyzing the armature reaction of a permanent magnet synchronous motor, the armature reaction inductance in the corresponding state is taken as a constant value to draw a phasor diagram and perform analysis, based on the premise that the synchronous motor stably operates at a synchronous speed and the load remains unchanged. It is impossible to dynamically analyze the armature reaction after a non-synchronous speed or load change with the same armature reaction inductance value. The technical solution of the embodiment of the present application takes into account the instantaneous change law of the armature reaction inductance, and is suitable for analyzing the change process of the armature reaction-related electrical signal when the working condition of the permanent magnet synchronous motor changes.

[0147] Figure 3 The overall flow chart of a method for calculating the instantaneous value of armature reaction inductance provided in an embodiment of the present application is shown in FIG. Figure 3 The overall implementation process of the method for calculating the instantaneous value of the armature reaction inductance is as follows: First, obtain the instantaneous value of the current i a and the rotor mechanical angle θ m Then, according to the instantaneous current value i a The current amplitude I is obtained by analysis max and the current phase angle θ i According to the rotor mechanical angle θ m And the number of motor pole pairs to get the rotor electrical angle θ e Secondly, according to the current phase angle θ i 、Rotor electrical angle θ e The phase angle γ of the current lagging the back EMF is calculated from the corresponding relationship between the back EMF and the rotor electrical angle. Finally, the rotor electrical angle θ e , the phase angle γ of the current lagging the back EMF, the preset direct-axis inductance L of the motor d And the motor's preset quadrature-axis inductance L qSubstituting it as input into the calculation formula of the preset measurement model, the instantaneous value of the armature reaction inductance of each phase can be calculated. This can realize the real-time measurement of the instantaneous value of the armature reaction inductance of each phase of the motor, which is convenient for the transient analysis of single-phase electricity. In addition, the instantaneous value of the armature reaction inductance of each phase can be measured independently without the need for coordinate transformation, which will not cause the original data to lose information. In addition, the influence of the motor rotor position and current phase on the armature reaction inductance can be considered, which can improve the measurement accuracy.

[0148] Figure 4 The schematic diagram of the principle structure of a device for calculating the instantaneous value of armature reaction inductance provided in the embodiment of the present application. Accordingly, the embodiment of the present application also provides a device for calculating the instantaneous value of armature reaction inductance, and the device for calculating the instantaneous value of armature reaction inductance includes: a current detection module 10, a rotor angle detection module 20 and a control module 30; the current detection module is used to detect the instantaneous value of the current of the motor and send it to the control module 30; the rotor angle detection module 20 is used to detect the rotor mechanical angle of the motor and send it to the control module 30; the control module 30 is used to: obtain the instantaneous value of the current of the motor and the rotor mechanical angle of the motor; calculate the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and the preset calculation model.

[0149] The control module 30 is electrically connected to the current detection module 10 and the rotor angle detection module 20. The control module may be a parameter measurement controller, such as a single chip microcomputer, etc., which may be specifically configured according to actual conditions and is not specifically limited here.

[0150] The technical solution of this embodiment provides a device for calculating the instantaneous value of armature reaction inductance, which includes: a current detection module, a rotor angle detection module and a control module; the current detection module is used to detect the instantaneous value of the current of the motor and send it to the control module; the rotor angle detection module is used to detect the rotor mechanical angle of the motor and send it to the control module; the control module is used to: obtain the instantaneous value of the current of the motor and the rotor mechanical angle of the motor; calculate the instantaneous value of the armature reaction inductance according to the preset direct axis inductance of the motor, the preset quadrature axis inductance of the motor, the instantaneous value of the current of the motor, the mechanical angle of the rotor of the motor and the preset calculation model. It can be seen that the device can directly calculate the instantaneous value of the armature reaction inductance by establishing a calculation model and only needs to obtain the instantaneous value of the current of the motor and the mechanical angle of the rotor. The method can take into account the influence of the motor rotor position and current phase on the armature reaction inductance, is simple and reliable, does not require coordinate transformation, and does not affect the information of the original data, that is, it does not cause the information of the original data to be lost.

[0151] In some embodiments, the control module 30 is also used to: determine the rotor electrical angle according to the rotor mechanical angle of the motor; determine the phase angle of the current lagging back electromotive force according to the instantaneous value of the motor current and the rotor electrical angle; and calculate the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and a preset measurement model.

[0152] In some embodiments, the calculation formula of the preset calculation model is:

[0153]

[0154] Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back EMF; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor.

[0155] In some embodiments, the current detection module is a current sensor, and the rotor angle detection module is a rotor angle position sensor.

[0156] In some embodiments, the control module is further used to: obtain the number of motor pole pairs; and determine the rotor electrical angle according to the rotor mechanical angle and the number of motor pole pairs.

[0157] In some embodiments, the control module is further used to: obtain the current phase angle according to the instantaneous value of the current; determine the phase angle of the current lagging back electromotive force according to the current phase angle, the rotor electrical angle, and the corresponding relationship between the back electromotive force and the rotor electrical angle.

[0158] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase b is:

[0159]

[0160] Among them, L bs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase b of the motor.

[0161] In some embodiments, the calculation formula for the instantaneous value of the armature reaction inductance of the motor phase c is:

[0162]

[0163] Among them, L cs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase c of the motor.

[0164] Figure 5is a schematic diagram of the structure of a motor test system provided in the embodiment of the present application. Correspondingly, the embodiment of the present application also provides a motor, see Figure 5 The motor 100 includes a variable frequency drive 101 and a device for measuring the instantaneous value of armature reaction inductance as described in any embodiment of the present application.

[0165] Among them, the motor is a three-phase permanent magnet synchronous motor.

[0166] For example, see Figure 5 The motor 100 includes a variable frequency drive 101, a parameter measurement controller 102, a current sensor 103 and a rotor angular position sensor 104. The variable frequency drive 101 is used to control the motor 100 to start and run stably at a synchronous speed. The current sensor 103 is used to detect and obtain the instantaneous value of the phase current of the motor and send it to the parameter measurement controller 102. The rotor angular position sensor 104 is used to detect and obtain the rotor mechanical angle and send it to the parameter measurement controller 102. The parameter measurement controller 102 is provided with a software algorithm of a preset measurement model. The parameter measurement controller 102 and the related software algorithm complete the processing of the collected sensor signals, and the sum of the current and inductance of each phase is calculated to one of the phases under the condition that the synchronous motor is symmetrical, and the influence of the armature reaction is considered only by the current of one phase and the equivalent armature reaction inductance, and the instantaneous value of the armature reaction inductance is calculated in real time.

[0167] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0168] The above is a detailed introduction to the method, device and motor for calculating the instantaneous value of the armature reaction inductance provided in the embodiments of the present application, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A method for calculating the instantaneous value of armature reaction inductance, characterized in that: include: Obtain the instantaneous value of the motor current and the mechanical angle of the motor rotor; The instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and a preset measurement model.

2. The method for calculating the instantaneous value of armature reaction inductance according to claim 1, characterized in that: The calculating of the instantaneous value of the armature reaction inductance according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and a preset measurement model comprises: Determining a rotor electrical angle according to a rotor mechanical angle of the motor; Determining the phase angle of the current lagging back electromotive force according to the instantaneous value of the current of the motor and the electrical angle of the rotor; The instantaneous value of the armature reaction inductance is calculated based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and the preset measurement model.

3. The method for calculating the instantaneous value of armature reaction inductance according to claim 2, characterized in that: The calculation formula of the preset measurement model is: Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back electromotive force; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor.

4. The method for calculating the instantaneous value of armature reaction inductance according to claim 2, characterized in that: Determining the rotor electrical angle according to the rotor mechanical angle includes: Get the number of motor pole pairs; The rotor electrical angle is determined according to the rotor mechanical angle and the number of motor pole pairs.

5. The method for calculating the instantaneous value of armature reaction inductance according to claim 2, characterized in that: Determining the phase angle of the current lagging back electromotive force according to the instantaneous value of the current and the rotor electrical angle, comprising: Analyzing and obtaining the current phase angle according to the instantaneous value of the current; The phase angle of the current lagging the back electromotive force is determined according to the current phase angle, the rotor electrical angle, and the corresponding relationship between the back electromotive force and the rotor electrical angle.

6. The method for calculating the instantaneous value of armature reaction inductance according to claim 2, characterized in that: The calculation formula of the instantaneous value of the armature reaction inductance of the motor phase b is: Among them, L bs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase b of the motor.

7. The method for calculating the instantaneous value of armature reaction inductance according to claim 2, characterized in that: The calculation formula of the instantaneous value of the armature reaction inductance of the motor phase c is: Among them, L cs (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase c of the motor.

8. A device for calculating the instantaneous value of armature reaction inductance, characterized in that: include: A current detection module, a rotor angle detection module and a control module; the current detection module is used to detect the instantaneous value of the current of the motor and send it to the control module; the rotor angle detection module is used to detect the rotor mechanical angle of the motor and send it to the control module; The control module is used to: obtain the instantaneous value of the current of the motor and the mechanical angle of the rotor of the motor; The instantaneous value of the armature reaction inductance is calculated according to the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the instantaneous value of the current of the motor, the rotor mechanical angle of the motor and a preset measurement model.

9. The device for calculating the instantaneous value of armature reaction inductance according to claim 8, characterized in that: The control module is also used to: determine the rotor electrical angle according to the rotor mechanical angle of the motor; Determining the phase angle of the current lagging back electromotive force according to the instantaneous value of the current of the motor and the electrical angle of the rotor; The instantaneous value of the armature reaction inductance is calculated based on the preset direct-axis inductance of the motor, the preset quadrature-axis inductance of the motor, the rotor electrical angle, the phase angle of the current lagging back electromotive force, and the preset measurement model.

10. The device for calculating the instantaneous value of armature reaction inductance according to claim 9, characterized in that: The calculation formula of the preset measurement model is: Among them, θ e is the rotor electrical angle; γ is the phase angle of the current lagging back electromotive force; L d is the preset direct-axis inductance of the motor; L q is the preset quadrature-axis inductance of the motor; L as (θ e ,γ) is the instantaneous value of the armature reaction inductance of phase a of the motor.

11. The device for calculating the instantaneous value of armature reaction inductance according to claim 8, characterized in that: The current detection module is a current sensor, and the rotor angle detection module is a rotor angle position sensor.

12. A motor, characterized in that: It comprises a variable frequency drive and a device for measuring the instantaneous value of armature reaction inductance as claimed in any one of claims 8 to 11.

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