Permanent magnet motor demagnetization fault diagnosis method based on high-frequency injection differential demodulation

Abstract

The invention discloses a permanent magnet motor demagnetization fault diagnosis method based on high-frequency injection differential demodulation, and the method comprises the steps: constructing a high-frequency excitation signal which can be executed in an in-orbit environment, extracting a high-frequency characteristic component caused by the change of a flux linkage through the differential demodulation, and combining the coupling relation between high-frequency impedance and flux linkage disturbance, on-line calculation of the flux linkage offset of the permanent magnet motor under the on-orbit condition is achieved, and therefore real-time recognition of the demagnetization state is completed. The method does not depend on the fundamental wave back electromotive force of the motor, can stably detect at zero-speed, low-speed and high-speed stages, and is suitable for all working conditions; parameter drift interference is eliminated through differential demodulation, the method is insensitive to changes of resistance and inductance of the motor, and the method adapts to a space extreme environment; the calculation steps are simple, the calculation amount is small, and the on-orbit real-time diagnosis requirement is met; hardware equipment does not need to be additionally arranged, and high-frequency signal injection and data processing can be achieved only through software optimization.

Description

Technical Field

[0001] This invention relates to a method for diagnosing demagnetization faults in permanent magnet motors based on high-frequency injection differential modulation, belonging to the technical field of fault diagnosis for aerospace permanent magnet motors. Background Technology

[0002] Permanent magnet motors, with their compact structure, high efficiency, excellent control precision, and high adaptability to the extreme temperatures, radiation, and vacuum environments of space, have become the primary drive system for spacecraft solar panel deployment mechanisms. During on-orbit operation, these motors perform critical actions such as driving the deployment hinges, unlocking the locking mechanism, and adjusting the attitude of the folding components. They are core actuators ensuring the spacecraft successfully establishes a power link and obtains a continuous energy supply. However, in recent years, several international spacecraft have experienced situations where solar panels failed to deploy normally after entering orbit, resulting in obstructed solar array deployment and ultimately leading to complete failure of the spacecraft. Such problems typically cause huge economic losses and the risk of major mission failures, representing one of the most serious types of malfunctions in aerospace engineering.

[0003] In practical engineering applications, when solar panels fail to deploy, one of the main tasks of the ground control center is to determine whether the problem is caused by severe demagnetization of the permanent magnet motor in the extreme space environment. This necessitates conducting on-orbit demagnetization fault diagnosis of the permanent magnet motor and transmitting the relevant information back to the ground for further analysis and processing. Against this backdrop, establishing a method capable of real-time on-orbit diagnosis of the demagnetization status of permanent magnet motors has crucial engineering value.

[0004] Currently, traditional technologies for demagnetization diagnosis of permanent magnet motors mainly include back EMF estimation, flux linkage identification methods based on observation models, and fault identification methods based on frequency domain features or intelligent algorithms. Among these, the back EMF estimation method relies on the fundamental back EMF generated by the motor's operation to calculate the flux linkage, making it impossible to obtain observable information at zero or low speeds. While the flux linkage identification method based on observation models can achieve flux linkage estimation to some extent, it is highly sensitive to motor parameters and easily affected by disturbances and measurement errors in the on-orbit environment. Diagnostic methods based on frequency domain analysis or intelligent algorithms often rely on large amounts of training samples or ground-based experimental features, making it difficult to meet the on-orbit diagnostic requirements of long-term unattended operation, high real-time performance, and limited sample size in spacecraft. In summary, existing technologies are difficult to directly apply to on-orbit demagnetization detection of permanent magnet motors used for aerospace solar panel deployment, necessitating a novel method for diagnosing permanent magnet motor demagnetization faults. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art. In view of the many problems of traditional permanent magnet motor demagnetization diagnosis, such as easy disturbance, measurement error, and harsh and limited sample acquisition, this invention innovatively proposes a permanent magnet motor demagnetization fault diagnosis method based on high-frequency injection differential modulation.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for diagnosing demagnetization faults in a permanent magnet motor based on high-frequency injection differential modulation, wherein the permanent magnet motor is a permanent magnet motor used for deploying aerospace solar panels, includes the following steps: S1 constructs and injects a high-frequency signal, and constructs the high-frequency response equation in the αβ coordinate system of the stator two-phase stationary coordinate system of the permanent magnet motor: U αh (t) and U βh (t) represents the high-frequency voltage excitation signal, U h ω represents the amplitude of a high-frequency voltage signal. h The frequency of the high-frequency voltage signal; S2 high-frequency current component extraction, sampling permanent magnet motor phase current i α (k) and i β (k), construct the difference operator formula: Extracting high-frequency components i αh (k) and i βh (k), where i α (k-1) and i β (k-1) is The permanent magnet motor phase current sampled seconds ago. Constructing the formula for high-frequency current amplitude: Calculate the amplitude of the high-frequency current I h (k); S3 calculates the high-frequency current deviation value, which is ΔI. h (k), ΔI h (k)=I h (k)-ΔI href ΔI href The high-frequency current reference value when the permanent magnet is not demagnetized is obtained by applying the same high-frequency voltage excitation signal through ground calibration. S4 calculates the flux linkage offset, and constructs an offset formula based on the coupling relationship between high-frequency impedance and flux linkage perturbation. Calculate the flux linkage offset Δψ f (k), where R s L is the stator winding resistance of a permanent magnet motor. s This refers to the stator inductance value of the permanent magnet motor. S5 constructs the flux linkage offset coefficient, using the flux linkage offset Δψ f (k) Constructing the flux linkage offset equation: Where D is the flux linkage offset coefficient, ψ f 0 represents the initial flux linkage of the permanent magnet motor; S6 performs demagnetization fault diagnosis, based on the magnetic flux offset coefficient D: D≤1% indicates no demagnetization, 1%<D≤5% indicates slight demagnetization, 5%<D≤10% indicates moderate demagnetization, and D>10% indicates severe demagnetization, thus completing the demagnetization fault diagnosis.

[0007] Preferably, in step S1, 0.05V dc ≤U h ≤0.2V dc V dc DC power supply voltage for spacecraft; f pwm This is the control frequency for the permanent magnet motor.

[0008] The beneficial effects of this invention are mainly reflected in: 1. It does not rely on the fundamental back EMF of the motor and can stably detect at zero speed, low speed, and high speed, making it applicable to all working conditions; 2. It eliminates parameter drift interference through differential demodulation, is insensitive to changes in motor resistance and inductance, and is suitable for extreme space environments; 3. The calculation steps are simple and the computational load is small, meeting the needs of real-time on-orbit diagnosis; 4. No additional hardware is required; high-frequency signal injection and data processing can be achieved solely through software optimization. Attached Figure Description

[0009] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating a method for diagnosing demagnetization faults in permanent magnet motors based on high-frequency injection differential modulation, according to the present invention. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0011] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the present application can be combined with each other.

[0012] To diagnose demagnetization faults in permanent magnet motors used for deploying aerospace solar panels, this invention constructs an on-orbit executable high-frequency excitation signal, uses differential demodulation to extract high-frequency characteristic components caused by flux linkage changes, and combines the coupling relationship between high-frequency impedance and flux linkage disturbance to achieve online calculation of flux linkage offset of permanent magnet motors under on-orbit conditions, thereby completing real-time identification of demagnetization status.

[0013] Specifically, such as Figure 1 As shown, this invention provides a method for diagnosing demagnetization faults in a permanent magnet motor based on high-frequency injection differential modulation. The permanent magnet motor is used for deploying aerospace solar panels. The method includes the following steps: S1 constructs and injects a high-frequency signal, and constructs the high-frequency response equation in the αβ coordinate system of the stator two-phase stationary coordinate system of the permanent magnet motor: U αh (t) and U βh (t) represents the high-frequency voltage excitation signal, U h ω represents the amplitude of a high-frequency voltage signal. h The frequency of the high-frequency voltage signal.

[0014] S2 high-frequency current component extraction, sampling permanent magnet motor phase current i α (k) and i β (k), construct the difference operator formula: Extracting high-frequency components i αh (k) and i βh (k), where i α (k-1) and i β (k-1) is The permanent magnet motor phase current sampled seconds ago. Constructing the formula for high-frequency current amplitude: Calculate the amplitude of the high-frequency current I h (k).

[0015] S3 calculates the high-frequency current deviation value, which is ΔI. h (k), ΔI h (k)=I h (k)-ΔI href ΔI hrefThe high-frequency current reference value when the permanent magnet is not demagnetized is obtained by applying the same high-frequency voltage excitation signal through ground calibration. S4 calculates the flux linkage offset, and constructs an offset formula based on the coupling relationship between high-frequency impedance and flux linkage perturbation. Calculate the flux linkage offset Δψ f (k), where R s L is the stator winding resistance of a permanent magnet motor. s This refers to the stator inductance value of the permanent magnet motor. S5 constructs the flux linkage offset coefficient, using the flux linkage offset Δψ f (k) Constructing the flux linkage offset equation: Where D is the flux linkage offset coefficient, ψ f 0 represents the initial flux linkage of the permanent magnet motor; S6 performs demagnetization fault diagnosis, based on the magnetic flux offset coefficient D: D≤1% indicates no demagnetization, 1%<D≤5% indicates slight demagnetization, 5%<D≤10% indicates moderate demagnetization, and D>10% indicates severe demagnetization, thus completing the demagnetization fault diagnosis.

[0016] In one specific embodiment, 0.05Vdc≤Uh≤0.2Vdc, where Vdc is the DC power supply voltage of the spacecraft; fpwm is the control frequency of the permanent magnet motor.

[0017] In one specific embodiment, the parameters of the aerospace permanent magnet motor are as follows: inductance Ls = 0.125H, stator resistance Rs = 0.5Ω, initial flux linkage ψf0 = 0.83Wb, DC bus voltage Vdc = 15V, and control frequency fpwm = 5kHz. The implementation process of the demagnetization fault diagnosis method for aerospace solar panel deployment permanent magnet motors based on high-frequency injection differential modulation is as follows: In the two-phase stationary coordinate system αβ of the stator of the permanent magnet motor, construct a high-frequency voltage excitation signal U of the following form. αh and U βh This signal is then injected into the stator windings of the motor to excite a high-frequency response signal related to changes in flux linkage. In this embodiment, Uh=0.2Vdc=3. .

[0018] Sample permanent magnet motor phase current i α (k) and i β (k), and extract the high-frequency component i using the following difference operator. αh (k) and i βh (k): iα(k-1) and iβ(k-1) are the phase currents of the permanent magnet motor sampled 0.0002 seconds ago, and the high-frequency current amplitude Ih(k) is calculated: Calculate the high-frequency current deviation value ΔIh(k).

[0019] Based on the coupling relationship between high-frequency impedance and flux disturbance, the flux offset Δψf(k) is calculated by substituting the current deviation value ΔIh(k) into the following formula: .

[0020] The flux linkage offset coefficient D is constructed using the flux linkage offset Δψf(k) as follows: .

[0021] In this embodiment, after obtaining the parameters, only the current deviation value needs to be substituted to satisfy the calculation of the flux linkage offset coefficient D, thereby realizing the demagnetization fault diagnosis through D.

[0022] As can be seen from the above description, it can stably detect motor fundamental back EMF without relying on it, and can be used in zero-speed, low-speed, and high-speed stages, making it applicable to all operating conditions; it eliminates parameter drift interference through differential demodulation, is not sensitive to changes in motor resistance and inductance, and is suitable for the extreme environment of space; the calculation steps are simple and the amount of calculation is small, meeting the needs of real-time on-orbit diagnosis; it does not require additional hardware equipment, and high-frequency signal injection and data processing can be achieved through software optimization alone.

[0023] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0024] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for diagnosing demagnetization faults in a permanent magnet motor based on high-frequency injection differential modulation, wherein the permanent magnet motor is a permanent magnet motor used for deploying aerospace solar panels, characterized in that... Includes the following steps: S1 constructs and injects a high-frequency signal, and constructs the high-frequency response equation in the αβ coordinate system of the stator two-phase stationary coordinate system of the permanent magnet motor: U αh (t) and U βh (t) represents the high-frequency voltage excitation signal, U h ω represents the amplitude of a high-frequency voltage signal. h The frequency of the high-frequency voltage signal; S2 high-frequency current component extraction, sampling permanent magnet motor phase current i α (k) and i β (k), construct the difference operator formula: Extracting high-frequency components i αh (k) and i βh (k), where i α (k-1) and i β (k-1) is The permanent magnet motor phase current sampled seconds ago. Constructing the formula for high-frequency current amplitude: Calculate the amplitude of the high-frequency current I h (k); S3 calculates the high-frequency current deviation value, which is ΔI. h (k), ΔI h (k)=I h (k)-ΔI href ΔI href The high-frequency current reference value when the permanent magnet is not demagnetized is obtained by applying the same high-frequency voltage excitation signal through ground calibration. S4 calculates the flux linkage offset, and constructs an offset formula based on the coupling relationship between high-frequency impedance and flux linkage perturbation. Calculate the flux linkage offset Δψ f (k), where R s L is the stator winding resistance of a permanent magnet motor. s This refers to the stator inductance value of the permanent magnet motor. S5 constructs the flux linkage offset coefficient, using the flux linkage offset Δψ f (k) Constructing the flux linkage offset equation: Where D is the flux linkage offset coefficient, ψ f 0 represents the initial flux linkage of the permanent magnet motor; S6 performs demagnetization fault diagnosis, based on the magnetic flux offset coefficient D: D≤1% indicates no demagnetization, 1%<D≤5% indicates slight demagnetization, 5%<D≤10% indicates moderate demagnetization, and D>10% indicates severe demagnetization, thus completing the demagnetization fault diagnosis.

2. The method for diagnosing demagnetization faults of permanent magnet motors based on high-frequency injection differential modulation according to claim 1, characterized in that: In step S1, 0.05V dc ≤U h ≤0.2V dc V dc DC power supply voltage for spacecraft; f pwm This is the control frequency for the permanent magnet motor.

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