Method and system for estimating rotational speed and rotor position of a permanent magnet synchronous motor of a dynamic pressure gas bearing gyro

Abstract

The application discloses a kind of dynamic pressure air float gyro permanent magnet synchronous motor rotating speed rotor position estimation method and system, it is related to position sensorless algorithm technical field, method includes obtaining to the three-phase counter electromotive force of permanent magnet synchronous motor is amplitude extraction and normalization, obtain the three-phase counter electromotive force of unitization;Unitized three-phase counter electromotive force is differentiated to time processing;To differential three-phase counter electromotive force is electric angular velocity extraction;According to the d-axis component in two-phase rotating coordinate axis system of three-phase counter electromotive force unitization determination;According to electric angular velocity and the d-axis component after PI regulator adjustment, the angular velocity of permanent magnet synchronous motor is calculated;According to angular velocity and pole pair number, the rotating speed is calculated;Angular velocity is integrated to time processing, and the predicted position of rotor is obtained, the application is differentiated to counter electromotive force, further obtained the stable frequency information of counter electromotive force, and then based on the stable frequency information, the rotating speed of motor and the position of rotor are more accurate.

Description

Technical Field

[0001] This invention relates to the field of sensorless algorithm technology, and in particular to a method and system for estimating the speed and rotor position of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor. Background Technology

[0002] Currently, existing methods for estimating the speed and rotor position of permanent magnet synchronous motors (PMSMs) calculate the motor speed and rotor position based on the motor terminal voltage. However, for dynamic pressure air-float gyroscope PMSMs, the rotor has no iron core, the motor impedance is relatively high, the motor inductance is extremely small, and the motor is greatly affected by speed and current. The motor terminal voltage fluctuates drastically and is unstable, so the motor position calculated based on the unstable terminal voltage is also inaccurate. Therefore, there is an urgent need for a speed and rotor position estimation method suitable for dynamic pressure air-float gyroscope PMSMs. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for estimating the speed and rotor position of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, which can improve the accuracy of speed and rotor position estimation of permanent magnet synchronous motors.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A method for estimating the rotor position and rotational speed of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, the method comprising:

[0006] Obtain the three back electromotive forces of a permanent magnet synchronous motor;

[0007] The amplitude of the three back electromotive forces is extracted and normalized to obtain the normalized three back electromotive forces;

[0008] Differentiate the normalized three-phase back electromotive force with respect to time to obtain the differential three-phase back electromotive force.

[0009] The electric angular velocity of the permanent magnet synchronous motor is obtained by extracting the electric angular velocity of the differential three-phase back electromotive force.

[0010] The d-axis components of the three back electromotive forces in the two-phase rotating coordinate system are determined based on the normalized three back electromotive forces.

[0011] The d-axis component is adjusted using a PI controller;

[0012] The angular velocity of the permanent magnet synchronous motor is calculated based on the adjusted d-axis component and the electric angular velocity.

[0013] The rotational speed of the permanent magnet synchronous motor is calculated based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor.

[0014] The angular velocity is integrated over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

[0015] Optionally, before extracting and normalizing the amplitudes of the three back electromotive forces, the method further includes:

[0016] The three back electromotive forces are subjected to low-pass filtering.

[0017] Optionally, after integrating the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor, the method further includes:

[0018] The filter phase compensation is determined based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor.

[0019] The final predicted position of the rotor of the permanent magnet synchronous motor is determined based on the filtered phase compensation and the predicted position.

[0020] Optionally, obtaining the three back electromotive forces of the permanent magnet synchronous motor specifically includes:

[0021] Obtain the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance, and inductance;

[0022] The three back electromotive forces of the permanent magnet synchronous motor are calculated based on the motor parameters.

[0023] Optionally, determining the d-axis component of the three-phase back electromotive force in the two-phase rotating coordinate system based on the normalized three-phase back electromotive force specifically includes:

[0024] The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

[0025] The present invention also provides a rotor position estimation system for a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, the system comprising:

[0026] The three-phase back EMF acquisition module is used to acquire the three-phase back EMF of the permanent magnet synchronous motor.

[0027] An amplitude extraction and normalization module is used to extract and normalize the amplitude of the three back electromotive forces to obtain a normalized three back electromotive forces.

[0028] The differential processing module is used to differentiate the normalized three back electromotive forces with respect to time to obtain the differential three back electromotive forces.

[0029] An electric angular velocity extraction module is used to extract the electric angular velocity of the differential three-phase back electromotive force to obtain the electric angular velocity of the permanent magnet synchronous motor.

[0030] The d-axis component acquisition module is used to determine the d-axis components of the three back electromotive forces in the two-phase rotating coordinate system based on the normalized three back electromotive forces.

[0031] An adjustment module is used to adjust the d-axis component using a PI controller;

[0032] An angular velocity calculation module is used to calculate the angular velocity of the permanent magnet synchronous motor based on the adjusted d-axis component and the electric angular velocity.

[0033] The rotational speed calculation module is used to calculate the rotational speed of the permanent magnet synchronous motor based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor.

[0034] An integral processing module is used to integrate the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

[0035] Optional, also includes:

[0036] The low-pass filtering module is used to perform low-pass filtering on the three back electromotive forces; the three back electromotive forces after low-pass filtering are used for amplitude extraction and normalization.

[0037] Optionally, it may also include: a phase compensation module; the phase compensation module includes:

[0038] A phase compensation unit is used to determine the filtered phase compensation based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor.

[0039] The final predicted position determination unit is used to determine the final predicted position of the rotor of the permanent magnet synchronous motor based on the filtered phase compensation and the predicted position.

[0040] Optionally, the three-phase back electromotive force acquisition module specifically includes:

[0041] The motor parameter acquisition unit is used to acquire the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance, and inductance.

[0042] The three-phase back electromotive force acquisition unit is used to calculate the three-phase back electromotive force of the permanent magnet synchronous motor based on the motor parameters.

[0043] Optionally, the d-axis component acquisition module specifically includes:

[0044] The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

[0045] According to specific embodiments provided by the present invention, the following technical effects are disclosed: The method for estimating the rotor position and rotational speed of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor provided by the present invention includes: acquiring the three-phase back electromotive force (EMF) of the permanent magnet synchronous motor; extracting and normalizing the amplitude of the three-phase back EMF to obtain a normalized three-phase back EMF; differentiating the normalized three-phase back EMF with respect to time to obtain a differential three-phase back EMF; extracting the electrical angular velocity of the differential three-phase back EMF to obtain the electrical angular velocity of the permanent magnet synchronous motor; determining the d-axis component of the three-phase back EMF in a two-phase rotating coordinate system based on the normalized three-phase back EMF; adjusting the d-axis component using a PI controller; calculating the angular velocity of the permanent magnet synchronous motor based on the adjusted d-axis component and the electrical angular velocity; calculating the rotational speed of the permanent magnet synchronous motor based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor; and integrating the angular velocity with respect to time to obtain the predicted position of the rotor of the permanent magnet synchronous motor. The present invention differentiates the back EMF to further obtain stable frequency information of the back EMF, thereby making the calculated rotational speed and rotor position of the motor more accurate based on this stable frequency information. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0047] Figure 1 This is a flowchart of the method for estimating the rotor position of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor provided in Embodiment 1 of the present invention;

[0048] Figure 2 This is a block diagram of the dynamic pressure air-floating gyroscope permanent magnet synchronous motor speed and rotor position estimation system provided in Embodiment 2 of the present invention. Detailed Implementation

[0049] 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.

[0050] The purpose of this invention is to provide a method and system for estimating the speed and rotor position of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor. By differentiating the back electromotive force, stable frequency information of the back electromotive force is obtained, and the speed of the motor and the position of the rotor are calculated based on the stable frequency information, thereby improving the accuracy of speed and rotor position estimation of the permanent magnet synchronous motor.

[0051] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] Example 1

[0053] like Figure 1 As shown, this invention provides a method for estimating the rotor position and rotational speed of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, the method comprising:

[0054] S1: Obtain the three back electromotive forces of the permanent magnet synchronous motor.

[0055] S2: Extract and normalize the amplitude of the three back electromotive forces to obtain a normalized three back electromotive forces.

[0056] S3: Differentiate the normalized three-phase back electromotive force with respect to time to obtain the differential three-phase back electromotive force.

[0057] S4: Extract the electric angular velocity from the differential three-phase back electromotive force to obtain the electric angular velocity of the permanent magnet synchronous motor.

[0058] S5: Determine the d-axis component of the three back electromotive force in the two-phase rotating coordinate system based on the normalized three back electromotive force.

[0059] S6: The d-axis component is adjusted using a PI controller.

[0060] S7: The angular velocity of the permanent magnet synchronous motor is calculated based on the adjusted d-axis component and the electric angular velocity.

[0061] S8: The rotational speed of the permanent magnet synchronous motor is calculated based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor.

[0062] S9: Integrate the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

[0063] In this embodiment, step S1 specifically includes:

[0064] Obtain the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance, and inductance;

[0065] Calculate the three back electromotive forces of the permanent magnet synchronous motor based on the motor parameters. Specifically:

[0066] First, the motor parameters of the dynamic pressure air-float gyroscope permanent magnet synchronous motor are obtained. In this embodiment, the motor parameters include resistance, inductance, and three-phase voltage u. U u V u W and three-phase current i U i V and i W The back electromotive force is extracted using the following equation (1), and the three back electromotive forces f are obtained. U f V and f W .

[0067]

[0068] In the formula, R is the motor resistance and L is the motor inductance.

[0069] In this embodiment, after calculating the three back electromotive forces, before extracting and normalizing the amplitude of the three back electromotive forces, the method further includes:

[0070] The three back electromotive forces are subjected to low-pass filtering, i.e., f is filtered. U f V and f W Perform low-pass filtering to obtain u MU u MV and u MW .

[0071] Then, according to formula (2), u MU u MV and u MW Amplitude extraction and normalization are performed to obtain the normalized three-phase back electromotive force F. U F V and F W .

[0072]

[0073] Among them, F X The three back electromotive forces are normalized, and k is a constant.

[0074] After obtaining the three back electromotive forces F U F V and F W Then, by differentiating time using equation (3), the differential three-phase back electromotive force F is obtained. U ′、F V ′ and F WThen, according to equation (4), the electric angular velocity is extracted to obtain the electric angular velocity ω′.

[0075]

[0076]

[0077] Then, based on the normalized three-phase back electromotive force, the d-axis components of the three-phase back electromotive force in the two-phase rotating coordinate system are determined, specifically including:

[0078] The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

[0079] In this embodiment, after abc / dq coordinate transformation, the d-axis component u of the three-phase back electromotive force in a two-phase rotating coordinate system is obtained. d and q-axis component u q Then u d As the setpoint for the PI controller, u is obtained after passing through the PI controller. d * u d * Adding ω′ to ω′ gives the angular velocity ω.

[0080] After obtaining the angular velocity ω, the rotational speed n of the dynamic pressure air-floating gyroscope permanent magnet synchronous motor can be calculated based on the number of pole pairs of the motor and formula (5).

[0081]

[0082] Where p is the number of pole pairs of the motor.

[0083] Simultaneously, the angular velocity ω can be integrated over time to obtain the predicted position angle θ′ of the rotor of the permanent magnet synchronous motor, as shown in the following formula:

[0084] θ′=∫ωdt (6)

[0085] It should be noted that a low-pass filter was used in this embodiment to perform low-pass filtering on the three back electromotive forces. Therefore, when estimating the rotor position of the permanent magnet synchronous motor, phase compensation is required. Therefore, after integrating the angular velocity over time to obtain the predicted rotor position of the permanent magnet synchronous motor, this embodiment further includes:

[0086] The filter phase compensation is determined based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor.

[0087] The final predicted position of the rotor of the permanent magnet synchronous motor is determined based on the filtered phase compensation and the predicted position.

[0088] Specifically, the filter phase compensation angle Δθ is a fixed value that is related to the voltage and current frequency of the motor and can be obtained by looking up a table. Then, the angle θ′ is added to the filter phase compensation Δθ to obtain the final predicted position θ of the permanent magnet synchronous motor rotor.

[0089] Compared with the prior art, the present invention has the following advantages:

[0090] 1. This invention calculates the three-phase back electromotive force based on the three-phase voltage, and differentiates the three-phase back electromotive force to obtain the frequency information of the three-phase back electromotive force. Although the three-phase back electromotive force calculated based on the three-phase voltage is unstable, its derivative, i.e. the frequency information, is stable. Therefore, the motor speed and rotor position calculated by this invention based on the stable frequency information are more accurate.

[0091] 2. The calculation process of this invention is clear, the calculation formula is simple, the number of variables involved in the calculation is small, the calculation speed is fast, it can adapt to high-frequency control, and it has universality.

[0092] Example 2

[0093] like Figure 2 As shown, the present invention also provides a rotor position estimation system for a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, the system comprising:

[0094] The three-phase back EMF acquisition module T1 is used to acquire the three-phase back EMF of the permanent magnet synchronous motor.

[0095] The amplitude extraction and normalization module T2 is used to extract and normalize the amplitude of the three back electromotive forces to obtain a normalized three back electromotive forces.

[0096] The differential processing module T3 is used to differentiate the normalized three back electromotive forces with respect to time to obtain the differential three back electromotive forces.

[0097] The electric angular velocity extraction module T4 is used to extract the electric angular velocity of the differential three-phase back electromotive force to obtain the electric angular velocity of the permanent magnet synchronous motor.

[0098] The d-axis component acquisition module T5 is used to determine the d-axis component of the three back electromotive forces in the two-phase rotating coordinate system based on the normalized three back electromotive forces.

[0099] The adjustment module T6 is used to adjust the d-axis component using a PI controller.

[0100] The angular velocity calculation module T7 is used to calculate the angular velocity of the permanent magnet synchronous motor based on the adjusted d-axis component and the electric angular velocity.

[0101] The rotational speed calculation module T8 is used to calculate the rotational speed of the permanent magnet synchronous motor based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor.

[0102] The integral processing module T9 is used to integrate the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

[0103] In this embodiment, the system further includes:

[0104] The low-pass filtering module is used to perform low-pass filtering on the three back electromotive forces; the three back electromotive forces after low-pass filtering are used for amplitude extraction and normalization.

[0105] In this embodiment, the system further includes: a phase compensation module; the phase compensation module includes:

[0106] The phase compensation unit is used to determine the filtered phase compensation based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor.

[0107] The final predicted position determination unit is used to determine the final predicted position of the rotor of the permanent magnet synchronous motor based on the filtered phase compensation and the predicted position.

[0108] In this embodiment, the three-phase back electromotive force acquisition module specifically includes:

[0109] The motor parameter acquisition unit is used to acquire the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance and inductance.

[0110] The three-phase back electromotive force acquisition unit is used to calculate the three-phase back electromotive force of the permanent magnet synchronous motor based on the motor parameters.

[0111] In this embodiment, the d-axis component acquisition module specifically includes:

[0112] The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

[0113] Each embodiment in this specification focuses on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be found in the method section.

[0114] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for estimating the rotor position and rotational speed of a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, characterized in that, The method includes: Obtaining the three-phase back electromotive force (EMF) of a permanent magnet synchronous motor specifically includes: acquiring the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance, and inductance; and calculating the three-phase back EMF f of the permanent magnet synchronous motor based on the motor parameters. U f V and f W The calculation formula is: Among them, u U u V u W For three-phase voltage, i U i V and i W R is the three-phase current, R is the motor resistance, and L is the motor inductance; The three back electromotive forces are low-pass filtered to obtain u. MU u MV and u MW ; The amplitude of the three back electromotive forces is extracted and normalized to obtain the normalized three back electromotive forces, as shown in the following formula: Among them, F X The three back electromotive forces are normalized, and k is a constant; Differentiate the normalized three-phase back electromotive force with respect to time to obtain the differential three-phase back electromotive force. The electric angular velocity of the permanent magnet synchronous motor is obtained by extracting the electric angular velocity of the differential three-phase back electromotive force. The d-axis components of the three back electromotive forces in the two-phase rotating coordinate system are determined based on the normalized three back electromotive forces. The d-axis component is adjusted using a PI controller; The angular velocity of the permanent magnet synchronous motor is calculated based on the adjusted d-axis component and the electric angular velocity. The rotational speed of the permanent magnet synchronous motor is calculated based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor, using the following formula: Where ω is the angular velocity and p is the number of pole pairs of the motor; The angular velocity is integrated over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

2. The method according to claim 1, characterized in that, After integrating the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor, the method further includes: The filter phase compensation is determined based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor. The final predicted position of the rotor of the permanent magnet synchronous motor is determined based on the filtered phase compensation and the predicted position.

3. The method according to claim 1, characterized in that, The determination of the d-axis component of the three-phase back electromotive force in the two-phase rotating coordinate system based on the normalized three-phase back electromotive force specifically includes: The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

4. A rotor position estimation system for a dynamic pressure air-floating gyroscope permanent magnet synchronous motor, characterized in that, The system includes: The three-phase back EMF acquisition module is used to acquire the three-phase back EMF of the permanent magnet synchronous motor; the three-phase back EMF acquisition module specifically includes: The motor parameter acquisition unit is used to acquire the motor parameters of the permanent magnet synchronous motor; the motor parameters include three-phase voltage, three-phase current, resistance, and inductance. The three-phase back electromotive force acquisition unit is used to calculate the three-phase back electromotive force f of the permanent magnet synchronous motor based on the motor parameters. U f V and f W The calculation formula is: Among them, u U u V u W For three-phase voltage, i U i V and i W R is the three-phase current, R is the motor resistance, and L is the motor inductance; The low-pass filtering module is used to perform low-pass filtering on the three back electromotive forces to obtain u. MU u MV and u MW The three back electromotive forces after low-pass filtering are used for amplitude extraction and normalization. The amplitude extraction and normalization module is used to extract and normalize the amplitude of the three back electromotive forces (EMFs) to obtain a normalized three back EMF, as shown in the following formula: Among them, F X The three back electromotive forces are normalized, and k is a constant; The differential processing module is used to differentiate the normalized three back electromotive forces with respect to time to obtain the differential three back electromotive forces. An electric angular velocity extraction module is used to extract the electric angular velocity of the differential three-phase back electromotive force to obtain the electric angular velocity of the permanent magnet synchronous motor. The d-axis component acquisition module is used to determine the d-axis components of the three back electromotive forces in the two-phase rotating coordinate system based on the normalized three back electromotive forces. An adjustment module is used to adjust the d-axis component using a PI controller; An angular velocity calculation module is used to calculate the angular velocity of the permanent magnet synchronous motor based on the adjusted d-axis component and the electric angular velocity. The rotational speed calculation module is used to calculate the rotational speed of the permanent magnet synchronous motor based on the angular velocity and the number of pole pairs of the permanent magnet synchronous motor, using the following formula: Where ω is the angular velocity and p is the number of pole pairs of the motor; An integral processing module is used to integrate the angular velocity over time to obtain the predicted position of the rotor of the permanent magnet synchronous motor.

5. The system according to claim 4, characterized in that, Also includes: Phase compensation module; The phase compensation module includes: A phase compensation unit is used to determine the filtered phase compensation based on the frequency of the three-phase voltage and the frequency of the three-phase current of the permanent magnet synchronous motor. The final predicted position determination unit is used to determine the final predicted position of the rotor of the permanent magnet synchronous motor based on the filtered phase compensation and the predicted position.

6. The system according to claim 4, characterized in that, The d-axis component acquisition module specifically includes: The normalized three-phase back electromotive force is subjected to an abc / dq coordinate transformation to obtain the d-axis component of the three-phase back electromotive force in a two-phase rotating coordinate system.

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