Method for rapidly estimating initial position of main motor based on estimation of rotor current characteristic value

Abstract

The invention relates to the technical field of electrically excited synchronous motors, in particular to a main motor initial position rapid estimation method based on estimation of a rotor current characteristic value, and the method comprises the steps: obtaining the three-phase rotor current of an exciter; obtaining a target rotor current of the exciter; acquiring excitation current of the main motor; obtaining excitation current variances of the main motor corresponding to the stator alpha shaft and the stator beta shaft; obtaining an angle compensation value of a main motor rotor; and obtaining an initial position estimation value of the main motor rotor. According to the method, under the condition that the initial position of the exciter is not known, the exciting current of the main motor is accurately estimated, the initial position of the rotor of the main motor is rapidly estimated, a large amount of data processing is not needed, and the complexity of the initial position identification process of the rotor of the main motor is simplified.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electrically excited synchronous motors, in particular to a method for rapidly estimating the initial position of a main motor based on estimated rotor current eigenvalues. BACKGROUND

[0002] In order to improve the reliability, maintainability and ground support capability of an aircraft, more-electric aircraft and all-electric aircraft are widely used in the aviation industry, and integrated starting and generating technology is a key technology in the more-electric aircraft. As a core part of the system, the starting generator uses the reversibility principle of the motor to drive the aviation load in the electric mode of the main generator, and has become the focus of research.

[0003] The brushless electrically excited starting and generating system is widely used in multiple fields due to its adjustable excitation characteristics, Figure 2 The basic structure of the brushless electrically excited starting and generating system is shown, including a main motor, a rotating rectifier and a secondary exciter, wherein the rotating rectifier connects the main motor and the secondary exciter. During starting, the on-board power supply provides a three-phase alternating current signal to the exciter, which is rectified by the rotating rectifier to provide a direct current excitation current for the main motor. At this time, the main motor can be approximated to an electrically excited synchronous motor. The secondary exciter only provides excitation during starting and does not participate in control. In the starting control of the brushless electrically excited motor, the initial position of the rotor of the main motor (the position of the N pole) is a very important physical quantity. The installation of a traditional position sensor undoubtedly increases the cost, volume and stability of the system, causing a decrease in system reliability, and in some cases, the initial position of the rotor needs to be obtained in a stationary state.

[0004] At present, there are many methods for estimating the initial value of the motor, but they are mainly for permanent magnet synchronous motors. The simple and practical methods mainly include the following: (1) a constant voltage space vector is applied to the stator to make the motor reach a "straight-through state" so that the rotor is turned to a specific position. However, when the initial position of the rotor needs to be obtained in a stationary state, this method is not suitable. (2) The saturation effect of the stator inductance is generally used. This method requires applying a voltage space vector with a constant amplitude to the stator for one cycle (360° electrical angle) and simultaneously collecting the three-phase stator currents. The disadvantage of this method is that the amount of data processed each time is too large. The step size and precision are often inversely proportional, and at the same time, for electrically excited synchronous motors, the flux linkage is not as stable as that of permanent magnet synchronous motors, so directly using this method will have a large estimation error.

[0005] Therefore, there is a large estimation error in the estimated excitation current in the existing estimation method, and in the subsequent process of estimating the initial position of the main motor, four positive and negative pulse signals need to be continuously injected at a specific time, and the excitation current estimation harmonic is eliminated by multiple difference methods. And because of the error in the estimated excitation current, the rotor side of the main motor is not completely measurable, and a continuous sinusoidal signal cannot be injected to improve the signal-to-noise ratio of the response signal.

[0006] Therefore, it is necessary to provide a main motor initial position fast estimation method based on estimated rotor current characteristic value to solve the above problems. SUMMARY

[0007] In order to solve the existing rotor position estimation method, continuous multiple voltage signals need to be injected to determine the positions of motor N and S poles. This process requires a large amount of data fitting processing, which is too cumbersome. Moreover, the estimated excitation current has an error, the rotor side of the main motor is not completely measurable, and a continuous sinusoidal signal cannot be injected to improve the signal-to-noise ratio of the response signal, resulting in low accuracy of the estimated rotor position. The present application provides a main motor initial position fast estimation method based on estimated rotor current characteristic value to solve the existing problems.

[0008] The present application provides a main motor initial position fast estimation method based on estimated rotor current characteristic value, which adopts the following technical scheme, comprising: According to the three-phase stator current and three-phase stator voltage of the exciter, the d axis rotor current and q axis rotor current of the exciter are obtained; d According to the q axis rotor current and axis rotor current of the exciter, the three-phase rotor current of the exciter is obtained; The derivative function module length of the three-phase rotor current of the exciter is taken as the target rotor current of the exciter; When the difference between the target rotor current of the exciter at the current time and the target rotor current of the exciter at the initial time meets the preset difference threshold, the characteristic value corresponding to the current three-phase rotor current of the exciter is collected, and the excitation current of the main motor is obtained according to the characteristic value; axis and stator axis of the main motor are injected with sinusoidal signals with the same amplitude and frequency, and the excitation current corresponding to the stator axis and stator axis of the main motor is collected; and the excitation current variance of the main motor corresponding to the stator axis and stator axis is obtained respectively; The excitation current variance of the main motor corresponding to the stator axis and stator Stator in the first half cycle of the shaft injection sinusoidal signal Shaft and stator The excitation current transformation quantity corresponding to the shaft, according to the stator Shaft and stator The excitation current transformation quantity corresponding to the shaft and the preset variation threshold value, obtain the angle compensation value of the main motor rotor; According to the angle compensation value, the stator Shaft and stator The excitation current variance of the main motor corresponding to the shaft obtains the initial position estimation value of the main motor rotor.

[0009] The further scheme of the application, the excitation machine d Shaft rotor current and q The steps of the shaft rotor current are: When the motor is in a static state, a three-phase symmetric three-phase stator voltage is applied to the stator side of the excitation machine, and the three-phase stator current of the excitation machine is collected; The three-phase stator voltage of the excitation machine is clark transformed to obtain The three-phase stator voltage of the excitation machine in the static coordinate system Shaft stator voltage and Shaft stator voltage; The three-phase stator current of the excitation machine is clark transformed to obtain The three-phase stator current of the excitation machine in the static coordinate system Shaft stator current and Shaft stator current; According to the three-phase stator voltage of the excitation machine Shaft stator voltage, Shaft stator voltage, Shaft stator current, Shaft stator current and the stator inductance of the excitation machine, and the mutual inductance of the excitation machine stator and rotor, obtain the d Shaft rotor current and q Shaft rotor current.

[0010] The further scheme of the application, according to the three-phase stator voltage of the excitation machine Shaft stator voltage, Shaft stator voltage, Shaft stator current, Shaft stator current and the stator inductance of the excitation machine, and the mutual inductance of the excitation machine stator and rotor, obtain the d Shaft rotor current and q The steps of the shaft rotor current are:

[0011] In the formula, Indicates the d Shaft rotor current of the excitation machine; Indicates the exciter q Shaft rotor current; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft stator current; Indicates the exciter Shaft stator current; This represents the stator inductance of the exciter; This indicates the stator resistance of the exciter; This indicates the mutual inductance between the exciter stator and rotor.

[0012] A further aspect of the present invention involves obtaining the three-phase rotor current of the exciter as follows:

[0013] In the formula, Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; This indicates the estimated position of the exciter rotor; Indicates the exciter d Shaft rotor current; Indicates the exciter q Shaft rotor current.

[0014] A further aspect of this invention is as follows: the step of obtaining the target rotor current of the exciter is:

[0015] In the formula, The target rotor current of the exciter. For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current.

[0016] A further aspect of the present invention is that the target rotor current of the exciter at the current moment ( ) and the target rotor current of the exciter at the initial moment ( When the difference between the current three-phase rotor current and the current value of the exciter is less than the preset difference threshold, the characteristic value corresponding to the current three-phase rotor current of the exciter is collected; wherein, the difference threshold is half of the preset initial value of the target rotor current. A further aspect of the present invention involves obtaining the excitation current of the main motor based on characteristic values ​​as follows:

[0017] In the formula, This represents the excitation current of the main motor; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents.

[0018] A further aspect of the present invention, based on the stator α shaft and The steps to obtain the angle compensation value of the main motor rotor, based on the excitation current change amount corresponding to the shaft and the preset change threshold, are as follows: According to the stator Shaft and stator The quadrant in which the initial position of the main motor rotor is located is determined by the excitation current change amount corresponding to the shaft and the preset change amount threshold. When the initial position of the main motor rotor is in the first quadrant, the angle compensation value of the main motor rotor is 0°; When the initial position of the main motor rotor is in the second quadrant, the angle compensation value of the main motor rotor is 180°; When the initial position of the main motor rotor is in the third quadrant, the angle compensation value of the main motor rotor is 180°; When the initial position of the main motor rotor is in the fourth quadrant, the angle compensation value of the main motor rotor is 360°.

[0019] A further aspect of the present invention, based on the stator Shaft and stator The steps for determining the quadrant of the main motor rotor's initial position, based on the excitation current change corresponding to the shaft and the preset change threshold, are as follows: The preset threshold for change is 0; In the stator The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is less than or equal to 0, the initial position of the main motor rotor is in the first quadrant; In the stator The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is greater than or equal to 0, the initial position of the main motor rotor is in the second quadrant; In the stator The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change value corresponding to the shaft is greater than 0, the initial position of the main motor rotor is located in the third quadrant; In the stator The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change corresponding to the shaft is less than 0, the initial position of the main motor rotor is in the fourth quadrant.

[0020] A further aspect of the present invention involves obtaining the estimated initial position of the main motor rotor based on the angle compensation value and the variance of the two excitation currents as follows:

[0021] In the formula, This represents the estimated initial position of the main motor rotor. stator The variance of the excitation current of the main motor corresponding to the shaft; stator The variance of the excitation current of the main motor corresponding to the shaft; This indicates the angle compensation value.

[0022] The beneficial effects of this invention are: By analyzing the characteristic values ​​of the three-phase rotor current of the excitation current and injecting sinusoidal signals, based on the relationship between the characteristic values ​​and the actual excitation current of the main motor, the excitation current of the main motor can be accurately estimated even when the initial position of the exciter is unknown. The initial position of the main motor rotor can also be quickly estimated without a large amount of data processing, thus simplifying the complexity of the initial position identification process of the main motor rotor. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for rapidly estimating the initial position of a main motor based on the estimated rotor current characteristic value, according to the present invention. Figure 2 This is a schematic diagram of a brushless electrically excited synchronous motor. Figure 3 A schematic diagram for calculating the target rotor current of the exciter; Figure 4This is a detailed flowchart illustrating a method for rapidly estimating the initial position of a main motor based on the estimated rotor current characteristic value, as described in an embodiment of the present invention. Figure 5 A schematic diagram showing the estimated results of the three-phase rotor current of the exciter; Figure 6 A comparison chart of the actual excitation current and the estimated excitation current of the main motor; Figure 7 Estimate the change in excitation current of the main motor; Figure 8 A comparison chart of the actual initial position and the estimated initial position of the main motor rotor; Figure 9 The graph shows the estimation error results of the initial position of the main motor at different positions. Detailed Implementation

[0025] 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.

[0026] Therefore, this invention provides an embodiment of a method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value, such as... Figure 1 and Figure 4 As shown, it includes: S1. Obtain the three-phase rotor current of the exciter; Specifically, based on the three-phase stator current and three-phase stator voltage of the exciter, the exciter's... d Shaft rotor current and q Shaft rotor current; based on the exciter's... d Shaft rotor current and q Shaft rotor current, obtain the three-phase rotor current of the exciter.

[0027] For example, such as Figure 3 As shown, in one specific embodiment, the exciter's... d Shaft rotor current and q The steps for determining the shaft rotor current are as follows: When the motor is stationary, apply a three-phase symmetrical three-phase stator voltage to the stator side of the exciter and collect the three-phase stator current of the exciter; perform Clark transform on the three-phase stator voltage of the exciter to obtain... Exciter in stationary coordinate system Shaft stator voltage and Shaft stator voltage; obtained by Clark transforming the three-phase stator current of the exciter. Exciter in stationary coordinate system Shaft stator current and Shaft stator current; based on the exciter's... Shaft stator voltage, Shaft stator voltage, Shaft stator current, The exciter's stator current, stator inductance, and mutual inductance between the stator and rotor are used to obtain the exciter's... d Shaft rotor current and q Shaft rotor current. In this embodiment, d Shaft rotor current and q The expression for the shaft rotor current is:

[0028] In the formula, Indicates the exciter d Shaft rotor current; Indicates the exciter q Shaft rotor current; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft stator current; Indicates the exciter Shaft stator current; This represents the stator inductance of the exciter; This indicates the stator resistance of the exciter; This indicates the mutual inductance between the exciter stator and rotor.

[0029] For example, in one specific embodiment, the expression for the three-phase rotor current of the exciter is:

[0030] In the formula, Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; This indicates the estimated position of the exciter rotor; Indicates the exciter d Shaft rotor current; Indicates the exciter q Shaft rotor current.

[0031] S2. Obtain the target rotor current of the exciter; Specifically, the three-phase rotor current of the exciter is obtained, and the magnitude of the derivative function of the three-phase rotor current of the exciter is taken as the target rotor current of the exciter.

[0032] For example, in this embodiment, the step of obtaining the three-phase rotor current of the exciter and using the magnitude of the derivative function of the three-phase rotor current of the exciter as the target rotor current of the exciter is as follows: Define the exciter. Phase rotor current The derivative of is Define exciter b Phase rotor current The derivative of is Define the exciter c Phase rotor current The derivative of is ,Will Phase rotor current, b Phase rotor current, c The magnitude of the derivative of the phase rotor current is used as the target rotor current. The expression for the target rotor current of the exciter is:

[0033] In the formula, The target rotor current of the exciter. For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current.

[0034] S3. Obtain the excitation current of the main motor; Specifically, when the difference between the target rotor current of the main motor at the current moment and the target rotor current at the initial moment meets the preset difference threshold, the characteristic value corresponding to the current three-phase rotor current of the exciter is collected, and the excitation current of the main motor is obtained based on the characteristic value.

[0035] For example, in one specific embodiment, the step of acquiring the characteristic value corresponding to the current three-phase rotor current of the exciter is as follows: Define the current time as time n, then the target rotor current at the current time is... Record the target rotor current at the current moment. and the preset target rotor current initial value The difference between them is considered to be less than a set difference threshold. When the signal reaches its peak value, the difference threshold is set to the preset initial value of the target rotor current. If the difference between the target rotor current of the main motor at the current moment and the target rotor current at the initial moment meets the preset difference threshold, then the characteristic value corresponding to the current three-phase rotor current of the exciter is collected. The characteristic value corresponding to the phase rotor current is denoted as The current state of the exciter The characteristic value corresponding to the phase rotor current is denoted as The current state of the exciter The characteristic value corresponding to the phase rotor current is denoted as .

[0036] For example, in one specific embodiment, the expression for the excitation current of the main motor is:

[0037] In the formula, This represents the excitation current of the main motor; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter. Characteristic values ​​corresponding to phase rotor currents.

[0038] S4. Obtain the stator Shaft and stator The variance of the excitation current of the main motor corresponding to the shaft; Specifically, respectively to the stator of the main motor Shaft and stator A sinusoidal signal with the same amplitude and frequency is injected into the shaft, and the stator of the main motor is sampled. Shaft and stator The excitation current corresponding to the shaft; and the stator current is obtained respectively. Shaft and stator The variance of the excitation current of the main motor corresponding to the shaft.

[0039] For example, in one specific embodiment, the main motor stator The excitation current of the shaft is denoted as and main motor stator The excitation current corresponding to the shaft is denoted as .

[0040] Among them, stator The variance of the excitation current of the shaft is: ,stator The variance of the excitation current of the shaft is: .

[0041] S5. Obtain the angle compensation value of the main motor rotor; Specifically, the stator of the main motor is obtained separately. Shaft and stator Stator during the first half-cycle of a sinusoidal signal injected into the shaft α shaft and The excitation current transformation quantity corresponding to the shaft is based on the stator. Shaft and stator The angle compensation value of the main motor rotor is obtained by measuring the excitation current change amount corresponding to the shaft and the preset change threshold.

[0042] For example, in one specific embodiment, the stator of the main motor is obtained. Shaft and stator Stator during the first half-cycle of a sinusoidal signal injected into the shaft Shaft and stator The steps for determining the excitation current transformation corresponding to the shaft are as follows: Since the excitation current variance can only reflect the magnitude of the sin and cos signals, it is necessary to check the excitation current change at the initial stage of the injected sinusoidal signal to obtain the quadrant of the initial position. Therefore, the change is first recorded on the stator of the main motor where the sinusoidal signal is injected. The axis enables the stator to operate within the first half-cycle. Excitation current transformation quantity corresponding to the shaft ; and the stator of the main motor recorded in the sinusoidal signal injection The axis enables the stator to operate within the first half-cycle. Excitation current transformation quantity corresponding to the shaft .

[0043] For example, in one specific embodiment, according to the stator Shaft and stator The steps to obtain the rotor angle compensation value of the main motor are as follows: based on the excitation current change amount corresponding to the shaft and the preset change threshold, the steps are: Shaft and stator The excitation current change value corresponding to the shaft and the preset change threshold are used to determine the quadrant in which the initial position of the main motor rotor is located. When the initial position of the main motor rotor is in the first quadrant, the angle compensation value of the main motor rotor is 0°. When the initial position of the main motor rotor is in the second quadrant, the angle compensation value of the main motor rotor is 180°. When the initial position of the main motor rotor is in the third quadrant, the angle compensation value of the main motor rotor is 180°. When the initial position of the main motor rotor is in the fourth quadrant, the angle compensation value of the main motor rotor is 360°.

[0044] In one specific embodiment, according to the stator Shaft and stator The steps for determining the quadrant of the main motor rotor's initial position, based on the excitation current change value corresponding to the shaft and the preset change threshold, are as follows: the preset change threshold is 0; in the stator... The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is less than or equal to 0, the initial position of the main motor rotor is in the first quadrant; in the stator... The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is greater than or equal to 0, the initial position of the main motor rotor is in the second quadrant; in the stator The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change corresponding to the shaft is greater than 0, the initial position of the main motor rotor is in the third quadrant; in the stator... The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change corresponding to the shaft is less than 0, the initial position of the main motor rotor is in the fourth quadrant. Then the stator... Shaft and stator The relationship between the excitation current transformation amount corresponding to the shaft, the preset change threshold, the quadrant in which the main motor rotor is initially located, and the angle compensation value of the main motor rotor is shown in Table 1. Table 1

[0045] S6. Obtain the estimated initial position of the main motor rotor; Specifically, based on the angle compensation value obtained in step S5 and the stator value obtained in step S4... Shaft and stator The initial position estimate of the main motor rotor is obtained by using the variance of the excitation current of the main motor corresponding to the shaft.

[0046] For example, in one specific embodiment, the expression for the initial position estimate of the main motor rotor is:

[0047] In the formula, This represents the estimated initial position of the main motor rotor. stator The variance of the excitation current of the main motor corresponding to the shaft; stator The variance of the excitation current of the main motor corresponding to the shaft; This indicates the angle compensation value.

[0048] The invention will be described below with reference to specific simulation data and accompanying drawings: This example uses MATLAB / Simulink to... Figure 2 The brushless electrically excited synchronous motor shown is subjected to simulation analysis. The actual initial position of the main motor of the brushless electrically excited synchronous motor is set to... The main motor is stationary, and the excitation frequency of the exciter stator is 200Hz.

[0049] The calculations are performed sequentially according to steps S1 to S6. The estimated rotor current of the exciter obtained from step S1 is as follows: Figure 5 As shown, the estimated excitation current of the main motor calculated by S3 is as follows: Figure 6 As shown. The variance of the excitation current calculated in step S4 is as follows. Figure 7 As shown, Figure 6 middle , , According to Table 1, when the initial position of the main motor rotor is in the fourth quadrant, the angle compensation value of the main motor rotor is 360°. In this example, the estimated and actual initial positions of the main motor rotor are as follows: Figure 8 As shown, the actual initial rotor position of the main motor is... The estimated initial position of the main motor is The calculated result of the initial position estimate of the main motor rotor is as follows: The actual initial position of the motor is 317.5°, so the estimated error is 1.2°. Wherein, Figure 9 The estimation results for the initial rotor position of the main motor at different angles, such as Figure 9 As shown, the position estimation error of the main motor at different initial positions is within... within degrees.

[0050] In summary, existing methods for estimating the initial position of multi-stage motors based on low-frequency square wave signal injection contain significant estimation errors in the estimated excitation current. Therefore, during subsequent initial position estimation of the main motor, four consecutive positive and negative pulse signals need to be injected at specific times, and the excitation current estimation harmonics are eliminated through multiple subtraction operations. Furthermore, due to the errors in the estimated excitation current, the rotor side of the main motor is not fully measurable, and a continuous sinusoidal signal cannot be injected to improve the signal-to-noise ratio of the response signal. In the method of this embodiment, since the actual excitation current has been obtained, the rotor side is fully measurable. The main motor can then be considered a brushed electrically excited synchronous motor. Therefore, when solving for the initial position, a long-duration sinusoidal signal can be injected to ensure the signal-to-noise ratio of the extracted signal and improve the accuracy of the position estimation. Moreover, it eliminates the need for multiple consecutive signal injections, requiring only two. Additionally, the maximum estimation error of existing multi-stage motor initial position estimation methods based on low-frequency square wave signal injection is generally within a certain range. In this method, the estimation error is basically within... Therefore, the estimation method of the present invention has higher accuracy and higher estimation efficiency in estimating the initial position compared with the prior art.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value, characterized in that, include: Based on the three-phase stator current and three-phase stator voltage of the exciter, obtain the exciter's... d Shaft rotor current and q Shaft rotor current; based on the exciter's... d Shaft rotor current and q Shaft rotor current, to obtain the three-phase rotor current of the exciter; The magnitude of the derivative function of the three-phase rotor current of the exciter is taken as the target rotor current of the exciter. When the difference between the target rotor current of the exciter at the current moment and the target rotor current of the exciter at the initial moment meets the preset difference threshold, the characteristic value corresponding to the current three-phase rotor current of the exciter is collected, and the excitation current of the main motor is obtained based on the characteristic value. to the stator of the main motor respectively Shaft and stator A sinusoidal signal with the same amplitude and frequency is injected into the shaft, and the stator of the main motor is sampled. Shaft and stator The excitation current corresponding to the shaft; and the stator current is obtained respectively. Shaft and stator The variance of the excitation current of the main motor corresponding to the shaft; Obtain the stator of the main motor respectively Shaft and stator Stator during the first half-cycle of a sinusoidal signal injected into the shaft Shaft and stator The excitation current transformation quantity corresponding to the shaft is based on the stator. Shaft and stator The angle compensation value of the main motor rotor is obtained by measuring the excitation current change amount corresponding to the shaft and the preset change threshold. Based on angle compensation value, stator Shaft and stator The initial position estimate of the main motor rotor is obtained by using the variance of the excitation current of the main motor corresponding to the shaft.

2. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, Obtain the exciter d Shaft rotor current and q The steps for controlling the rotor current are as follows: When the motor is stationary, a three-phase symmetrical three-phase stator voltage is applied to the stator side of the exciter, and the three-phase stator current of the exciter is collected. The three-phase stator voltage of the exciter is obtained by Clark transformation. Exciter in stationary coordinate system Shaft stator voltage and Shaft-stator voltage; The Clarke transform of the three-phase stator current of the exciter is obtained Exciter in stationary coordinate system Shaft stator current and Shaft stator current; According to the exciter Shaft stator voltage, Shaft stator voltage, Shaft stator current, The exciter's stator current, stator inductance, and mutual inductance between the stator and rotor are used to obtain the exciter's... d Shaft rotor current and q Shaft rotor current.

3. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 2, characterized in that, According to the exciter Shaft stator voltage, Shaft stator voltage, Shaft stator current, The exciter's stator current, stator inductance, and mutual inductance between the stator and rotor are used to obtain the exciter's... d Shaft rotor current and q The steps for controlling the rotor current are as follows: In the formula, Indicates the exciter d Shaft rotor current; Indicates the exciter q Shaft rotor current; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft-stator voltage; Indicates the exciter Shaft stator current; Indicates the exciter Shaft stator current; This represents the stator inductance of the exciter; This indicates the stator resistance of the exciter; This indicates the mutual inductance between the exciter stator and rotor.

4. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, The steps to obtain the three-phase rotor current of the exciter are as follows: In the formula, Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; Indicates the exciter Phase rotor current; This indicates the estimated position of the exciter rotor; Indicates the exciter d Shaft rotor current; Indicates the exciter q Shaft rotor current.

5. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, The steps to obtain the target rotor current of the exciter are as follows: In the formula, The target rotor current of the exciter. For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current, For the exciter The derivative of the phase rotor current.

6. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, When the difference between the target rotor current of the exciter at the current moment and the target rotor current of the exciter at the initial moment is less than a preset difference threshold, the characteristic value corresponding to the current three-phase rotor current of the exciter is collected; wherein, the difference threshold is half of the preset initial value of the target rotor current of the exciter.

7. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, The steps for obtaining the excitation current of the main motor based on the characteristic value are as follows: In the formula, This represents the excitation current of the main motor; Indicates the current state of the exciter Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter Characteristic values ​​corresponding to phase rotor currents; Indicates the current state of the exciter Characteristic values ​​corresponding to phase rotor currents.

8. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, According to the stator Shaft and stator The steps to obtain the angle compensation value of the main motor rotor, based on the excitation current change amount corresponding to the shaft and the preset change threshold, are as follows: According to the stator Shaft and stator The quadrant in which the initial position of the main motor rotor is located is determined by the excitation current change amount corresponding to the shaft and the preset change amount threshold. When the initial position of the main motor rotor is in the first quadrant, the angle compensation value of the main motor rotor is 0°; When the initial position of the main motor rotor is in the second quadrant, the angle compensation value of the main motor rotor is 180°; When the initial position of the main motor rotor is in the third quadrant, the angle compensation value of the main motor rotor is 180°; When the initial position of the main motor rotor is in the fourth quadrant, the angle compensation value of the main motor rotor is 360°.

9. A method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value, as described in claim 8, is characterized in that... According to the stator Shaft and stator The steps for determining the quadrant of the main motor rotor's initial position, based on the excitation current change corresponding to the shaft and the preset change threshold, are as follows: The preset threshold for change is 0; In the stator The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is less than or equal to 0, the initial position of the main motor rotor is in the first quadrant; In the stator The excitation current change corresponding to the shaft is less than 0, and the stator When the excitation current change corresponding to the shaft is greater than or equal to 0, the initial position of the main motor rotor is in the second quadrant; In the stator The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change value corresponding to the shaft is greater than 0, the initial position of the main motor rotor is located in the third quadrant; In the stator The excitation current change corresponding to the shaft is greater than or equal to 0, and the stator When the excitation current change corresponding to the shaft is less than 0, the initial position of the main motor rotor is in the fourth quadrant.

10. The method for rapid estimation of the initial position of a main motor based on the estimated rotor current characteristic value as described in claim 1, characterized in that, The steps to obtain the initial position estimate of the main motor rotor based on the angle compensation value and the variance of the two excitation currents are as follows: In the formula, This represents the estimated initial position of the main motor rotor. stator The variance of the excitation current of the main motor corresponding to the shaft; stator The variance of the excitation current of the main motor corresponding to the shaft; This indicates the angle compensation value.

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