Permanent magnet synchronous motor turn-to-turn short circuit fault diagnosis method and system based on switching frequency
By proposing a fault diagnosis method for inter-turn short circuits in permanent magnet synchronous motors based on switching frequency, and using Park transform and high-frequency negative sequence component method to extract fault feature signals, this method solves the diagnostic problems of unclear initial fault features and complex operating conditions in traditional methods, and achieves accurate identification and location of inter-turn short circuit faults.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional motor fault diagnosis methods struggle to accurately identify inter-turn short-circuit faults in the early stages of a fault, especially under complex operating conditions where the fault characteristics are not obvious. The reliability and accuracy of existing methods are affected when the motor speed changes frequently.
A fault diagnosis method for inter-turn short circuits in permanent magnet synchronous motors based on switching frequency is adopted. By real-time acquisition of the three-phase voltage and rotation speed of the motor, the fault feature signals of the direct axis and quadrature axis are extracted using Park transform and high-frequency negative sequence component method. Combined with bandpass filter filtering, fault feature signals of fixed frequency are obtained, and the presence of fault is determined based on amplitude, and the fault phase is located.
It improves the ability to identify inter-turn short-circuit characteristics in the early stage of a fault, reduces the impact of complex operating conditions on fault feature extraction, and enhances the accuracy and reliability of fault diagnosis.
Smart Images
Figure CN121856783A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method and system for diagnosing inter-turn short circuit faults in permanent magnet synchronous motors based on switching frequency, particularly concerning inter-turn short circuit faults. It belongs to the field of spacecraft integrated testing technology, especially for detection methods targeting motors with frequent speed changes and unclear initial fault characteristics. Background Technology
[0002] Inter-turn short circuit faults can lead to the generation of negative sequence current in motors. Traditional fault diagnosis methods are based on the fundamental frequency f1 of the motor current for fault analysis. However, the actual operating conditions of motors are very complex. Not only do the frequently changing operating speeds increase the difficulty of fault feature extraction, but the characteristics of inter-turn short circuits are not very obvious in the early stage of the fault, which greatly reduces the reliability of traditional fault diagnosis methods.
[0003] (1) The initial characteristics of the fault are not obvious. Firstly, in the initial stages of a fault, its impact on the motor system is relatively weak, and the characteristics and phenomena of the fault are not obvious, making it difficult to identify. Furthermore, due to inherent asymmetries in the motor system's manufacturing process, even in the absence of a fault, a normally stable motor system will exhibit certain characteristic quantities, increasing the difficulty of fault diagnosis. Most serious faults in motor systems develop from initial minor faults. Therefore, quantifying the severity of faults and incorporating it into fault indicators is a necessary consideration. Simultaneously, preventing the gradual development of minor faults and avoiding the influence of other factors to accurately identify initial faults are also areas requiring ongoing in-depth research.
[0004] (2) Difficulty in extracting fault features under complex working conditions Most current fault diagnosis methods for motor systems focus on in-depth research of a single type of fault. However, in actual operation, multiple fault scenarios can occur, such as inter-turn short circuits, eccentricity, and demagnetization. Therefore, it's impossible to apply a single-fault-type diagnostic method for condition monitoring under complex operating conditions. Furthermore, different fault types may exhibit similar fault characteristics, reducing diagnostic effectiveness and making it difficult to distinguish the fault condition, cause, and severity. Even for the same fault type, differences exist between motor systems, and the methods are further influenced by factors such as speed and load, significantly limiting the effectiveness of diagnostic methods. Summary of the Invention
[0005] The technical problem solved by this invention is to address the shortcomings of traditional motor fault diagnosis methods by designing a method and system for diagnosing inter-turn short-circuit faults in permanent magnet synchronous motors based on switching frequency, thereby solving problems such as unclear initial fault characteristics and difficulty in extracting fault characteristics under complex operating conditions.
[0006] The solution of this invention is: a method for diagnosing inter-turn short-circuit faults in permanent magnet synchronous motors based on switching frequency, the method comprising the following steps: S1. Real-time acquisition of the three-phase voltage of the permanent magnet synchronous motor. , , and rotational speed ; S2. Extract the three-phase voltage of the permanent magnet synchronous motor. , , The intermediate frequency is Direct-axis fault characteristic signals and quadrature-axis fault characteristic signals; This refers to the switching frequency of the permanent magnet synchronous motor. S3. Based on the amplitude of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, perform inter-turn short-circuit fault diagnosis, provide an indicator of whether the permanent magnet synchronous motor has experienced an inter-turn short-circuit fault, and send it to the fault characteristic location unit; S4. If an inter-turn short circuit fault occurs in the permanent magnet synchronous motor, the faulty phase of the permanent magnet synchronous motor can be located based on the fault characteristic signal extracted from the three-phase voltage of the permanent magnet synchronous motor.
[0007] Preferably, the amplitudes of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal are obtained by the following method: Real-time acquisition of three-phase voltage of permanent magnet synchronous motor , , and rotational speed ; The three-phase voltage of the permanent magnet synchronous motor was collected. , , Conduct based on The Park transform converts the high-frequency negative-sequence components caused by inter-turn short-circuit faults into components with frequencies of 1000-10000. Direct-axis voltage signal and quadrature-axis voltage signal; A bandpass filter with a center frequency of twice the switching frequency is used to filter the Park-transformed direct-axis voltage signal and quadrature-axis voltage signal to obtain the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal, and the amplitude of the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal is obtained.
[0008] Preferably, the permanent magnet synchronous motor is considered to have experienced an inter-turn short circuit fault if the following condition is met; otherwise, it is considered that the permanent magnet synchronous motor does not have an inter-turn short circuit fault: .
[0009] in, The amplitude of the characteristic signal of a direct shaft fault. The amplitude of the characteristic signal of the cross-axis fault. This serves as a fault detection threshold.
[0010] Preferably, the fault judgment threshold Frequency can be selected The motor voltage amplitude coefficient C1 is 10%.
[0011] Preferably, the method for locating the faulty phase of the permanent magnet synchronous motor is as follows: Obtain the amplitude values of the three-phase direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal of the permanent magnet synchronous motor, and calculate the sum of the squares of the amplitude values of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, which is denoted as the three-phase direct- and quadrature-axis power. Based on the principle that "the power of the faulty phase's right-angle shaft is significantly lower than the power of the other two phases' right-angle shaft by more than 15%", the faulty phase of the permanent magnet synchronous motor is located.
[0012] Another technical solution of the present invention is: a fault diagnosis system for inter-turn short circuit of permanent magnet synchronous motor based on switching frequency, the system comprising a fault feature extraction unit and a fault feature location unit; The fault feature extraction unit collects the three-phase voltage of the permanent magnet synchronous motor. , , and rotational speed The three-phase voltage of a permanent magnet synchronous motor is extracted using the high-frequency negative sequence component method. , , The intermediate frequency is The system identifies the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, and performs inter-turn short-circuit fault diagnosis based on the amplitude of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, providing an indicator of whether the permanent magnet synchronous motor has experienced an inter-turn short-circuit fault, and sends it to the fault characteristic location unit; This refers to the switching frequency of the permanent magnet synchronous motor. The fault feature location unit can locate the faulty phase of the permanent magnet synchronous motor based on the fault feature signals extracted from the three-phase voltage of the permanent magnet synchronous motor if an inter-turn short circuit fault occurs in the permanent magnet synchronous motor.
[0013] Preferably, the amplitudes of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal are obtained by the following method: Real-time acquisition of three-phase voltage of permanent magnet synchronous motor , , and rotational speed ; Three-phase voltage of a permanent magnet synchronous motor (PMSM) was collected. , , Conduct based on The Park transform converts the high-frequency negative-sequence components caused by inter-turn short-circuit faults into components with frequencies of 1000-10000. Direct-axis voltage signal and quadrature-axis voltage signal; A bandpass filter with a center frequency of twice the switching frequency is used to filter the Park-transformed direct-axis voltage signal and quadrature-axis voltage signal to obtain the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal, and the amplitude of the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal is obtained.
[0014] Preferably, the permanent magnet synchronous motor is considered to have experienced an inter-turn short circuit fault if the following condition is met; otherwise, it is considered that the permanent magnet synchronous motor does not have an inter-turn short circuit fault: .
[0015] in, The amplitude of the characteristic signal of a direct shaft fault. The amplitude of the characteristic signal of the cross-axis fault. This serves as a fault detection threshold.
[0016] 9. A fault diagnosis system for inter-turn short circuits in a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that the bandpass filter is a digital FIR filter with a bandwidth of [missing information]. , The fundamental frequency has a suppression ratio greater than 30dB.
[0017] Preferably, the method for locating the faulty phase of the permanent magnet synchronous motor is as follows: Obtain the amplitude values of the three-phase direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal of the permanent magnet synchronous motor, and calculate the sum of the squares of the amplitude values of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, which is denoted as the three-phase direct- and quadrature-axis power. Based on the principle that "the power of the faulty phase's right-angle shaft is significantly lower than the power of the other two phases' right-angle shaft by more than 15%", the faulty phase of the permanent magnet synchronous motor is located.
[0018] The advantages of this invention compared to the prior art are: (1) This invention proposes a method based on switching frequency The method for diagnosing inter-turn short circuit faults in permanent magnet synchronous motors uses twice the switching frequency to replace the motor's operating frequency, amplifying the fault characteristics of inter-turn short circuits in the early stages of the fault.
[0019] (2) The present invention combines the negative sequence component method to extract the high-frequency negative sequence component at twice the switching frequency, thereby reducing the influence of motor operating conditions on the extraction of fault feature signals. Attached Figure Description
[0020] Figure 1This is an example of an inter-turn short-circuit fault model in this invention. Figure 2 This is a d-axis voltage spectrum diagram of a healthy motor after reverse coordinate transformation according to an embodiment of the present invention; Figure 3 This is a q-axis voltage spectrum diagram of a healthy motor after reverse coordinate transformation according to an embodiment of the present invention; Figure 4 This is the d-axis voltage spectrum of the inter-turn short-circuit motor after the reverse coordinate transformation according to an embodiment of the present invention; Figure 5 This is the q-axis voltage spectrum of the inter-turn short-circuit motor after the reverse coordinate transformation according to an embodiment of the present invention; Figure 6 This is a flowchart of the inter-turn short-circuit fault diagnosis method according to an embodiment of the present invention. Detailed Implementation
[0021] 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.
[0022] When a permanent magnet synchronous motor experiences an inter-turn short-circuit fault, a new closed loop is formed between the turns of the winding, and the fault current... It will flow through the short-circuit resistor This causes the magnetic flux distribution inside the motor to become distorted.
[0023] like Figure 1 The figure shows the mathematical model of a three-phase permanent magnet synchronous motor. An inter-turn short-circuit fault point is set on its A-phase winding, dividing the original impedance of the A-phase winding into two segments. The inductance of the part connected in parallel with the fault point is... The resistance is The inductance of the part connected in series with the fault point is The resistance is .
[0024] Inter-turn short circuits disrupt the symmetrical structure of the three-phase windings of a permanent magnet synchronous motor, causing the three-phase voltage and current to no longer be symmetrical, resulting in the neutral point voltage no longer being zero. The voltage expression under an inter-turn short circuit fault is as follows: (1) In the formula, , , These are the phase voltages of the three phases A, B, and C of the motor, respectively; , , These are the phase currents of the three phases A, B, and C of the motor, respectively; The impedance of the motor stator winding; This is the neutral point voltage of the motor stator winding; , , These are the magnetic flux linkages of the three phases A, B, and C of the motor, respectively; , , These are the self-inductances of the three-phase windings of the motor; , , These are the mutual inductances of the three-phase windings of the motor; This is the impedance of the motor stator winding. Inter-turn short-circuit fault factor, Differentiation with respect to time.
[0025] To accurately reflect the severity of inter-turn short circuits, the inter-turn short circuit fault factor is set as follows: (2) Substituting the first line of equation (1) into the fourth line, we can further derive the expression for the fault current as follows: (3) Because the destruction of the symmetrical structure of the three-phase windings will limit its ability to suppress the third harmonic, the third harmonic component of the rotor permanent magnet flux linkage cannot be ignored.
[0026] (4) In the formula, This represents the fundamental flux linkage amplitude of the motor. This represents the amplitude of the third harmonic flux linkage of the motor. This refers to the working angle of the motor.
[0027] Performing the Park transformation on equation (1) yields... (5) In the formula, , These are the direct-axis and quadrature-axis voltages of the motor, respectively. , These are the direct-axis and quadrature-axis currents of the motor, respectively. This represents the angular velocity of the motor. , , These are the direct-axis, quadrature-axis, and zero-axis inductances of the motor; direct-axis flux linkage. Cross-axis magnetic flux Zero-axis magnetic flux Faulty magnetic flux The expression is (6) The expressions for the direct and quadrature axis voltages can be rearranged to obtain... (7) The direct-axis current of the motor under fault conditions and motor cross-axis current The expression can be represented as (8) To further analyze the disturbances introduced by inter-turn short-circuit faults, it is necessary to analyze the characteristics of the fault current and reorganize the expression for the fault current. (9) The parameters in the formula are (10) To simplify the subsequent feature analysis, the fault current is rewritten as follows: (11) In the formula, , These are the fundamental and third harmonic amplitudes of the inter-turn short-circuit fault current of the motor, respectively. , These are the fundamental and third harmonic phases of the inter-turn short-circuit fault current of the motor, respectively.
[0028] Substituting equation (11) into equation (8) yields (12) Equation (12) reveals that inter-turn short-circuit faults introduce a negative-sequence component into the motor current. This negative-sequence current is converted into twice the fundamental frequency in a two-phase rotating coordinate system. Similarly, a similar change occurs in the high-frequency components of the current, where... The angular velocity is the switching frequency. Angular velocity at the fundamental frequency. This represents the initial phase of the fundamental wave. For frequency The motor voltage amplitude coefficient is used to extract the high-frequency component of the fault current, resulting in a frequency of [frequency value missing]. Fault current The expression is: (13) In the formula, the frequency is The phase relationship of the fault current is: (14) This represents the phase of the fault current.
[0029] According to equations (8) and (13), the frequency is: The right-angle fault current is (15) in, For frequency The direct-axis fault current component, The frequency is 2fs±f1 for the direct-axis fault current component.
[0030] The above analysis reveals that inter-turn short-circuit faults not only introduce negative sequence current but also alter the high-frequency components of the current. According to Faraday's law of electromagnetic induction, the frequency is... The fault information within the high-frequency current signal is further amplified into a high-frequency voltage signal in the stator winding. This voltage signal is more sensitive to inter-turn short-circuit faults and can be used for fault diagnosis. The expression for the high-frequency fault voltage of the stator winding is: (16) According to (16), it can be analyzed that an inter-turn short circuit fault will affect the frequency of The positive-order components will also introduce high-frequency negative-order components, so a system based on... The negative-sequence component method converts it into a fixed frequency. Signal extraction, namely the high-frequency negative sequence component method, such as... Figures 2-5 As shown, this serves as the basis for diagnosing inter-turn short-circuit faults.
[0031] The fault feature localization unit compares the high-frequency voltage components of the healthy motor and the faulty motor, and can detect that in the healthy motor, the frequency is... The voltage signal contains only high-frequency positive-sequence components, and its voltage relationship expression is: (17) In the formula, , Frequency The amplitude and phase of the positive sequence voltage of the stator winding.
[0032] When an inter-turn short-circuit fault exists, the fault current will be introduced into the stator winding at a frequency of [frequency value missing]. The new voltage signal. This signal contains not only high-frequency positive-sequence components, but also special high-frequency negative-sequence components, which can be represented as... (18) In the formula, , Frequency The amplitude and phase of the negative sequence voltage of the stator winding.
[0033] Because the relative positions of the fault point and each phase winding are different, the mutual inductance between the faulty coil and each phase winding is... The harmonic voltage signals of the faulty phase will be very different, resulting in a significant difference between the harmonic voltage signals of the faulty phase and those of the other normal phases. This can be observed by examining the frequency of each phase. Changes in harmonic voltage can help locate the faulty phase.
[0034] Based on the above theoretical derivation, this invention proposes a method for diagnosing inter-turn short-circuit faults based on switching frequency, specifically the high-frequency negative-sequence component. This method utilizes inverse coordinate transformation to convert the high-frequency negative-sequence component containing inter-turn short-circuit fault information into a voltage signal with a frequency twice the switching frequency, using its amplitude as the basis for fault diagnosis. The feature quantity extracted by this method is of a fixed frequency and is not affected by speed changes, which is beneficial for filter design and feature value extraction. Furthermore, the winding voltage has a certain amplification effect on high-frequency signals, enhancing the fault information in the high-frequency signal and improving the accuracy of fault diagnosis. Simultaneously, a method for locating the inter-turn short-circuit fault phase is proposed. The relative amplitude changes of the high-frequency voltage signals of each phase winding can determine the location of the faulty phase, providing conditions for subsequent processing.
[0035] The core idea of this invention is: to use the three-phase voltage of a permanent magnet synchronous motor , , As input conditions, these conditions are substituted into the fault feature extraction unit, and the high-frequency negative sequence component method proposed in this invention is used to extract the frequency... The fault information contained in the high-frequency signal is converted into a fixed frequency obtained by stripping away the normal signal. The fault characteristics are used to diagnose inter-turn short circuit faults, and the fault characteristic location unit is used to locate the specific fault phase.
[0036] This invention provides a fault diagnosis system for inter-turn short circuits in permanent magnet synchronous motors based on switching frequency, comprising a fault feature extraction unit and a fault feature localization unit. Its features are as follows: The fault feature extraction unit collects the three-phase voltage of the permanent magnet synchronous motor. , , and rotational speed The three-phase voltage of a permanent magnet synchronous motor is extracted using the high-frequency negative sequence component method. , , The intermediate frequency is The system identifies the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, and performs inter-turn short-circuit fault diagnosis based on the amplitude of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, providing an indicator of whether the permanent magnet synchronous motor has experienced an inter-turn short-circuit fault, and sends it to the fault characteristic location unit; This refers to the switching frequency of the permanent magnet synchronous motor. The fault feature location unit can locate the faulty phase of the permanent magnet synchronous motor based on the fault feature signals extracted from the three-phase voltage of the permanent magnet synchronous motor if an inter-turn short circuit fault occurs in the permanent magnet synchronous motor.
[0037] The implementation process of this invention is described in detail below. This invention provides a method for diagnosing inter-turn short-circuit faults in permanent magnet synchronous motors, such as... Figure 6 As shown, the specific steps include the following: (1) Real-time acquisition of three-phase voltage of permanent magnet synchronous motor , , and rotational speed This serves as the input basis for fault diagnosis; (2) The three-phase voltage of the permanent magnet synchronous motor was collected. , , Conduct based on The Park transform converts the high-frequency negative-sequence components caused by inter-turn short-circuit faults into components with frequencies of 1000-10000. The direct-axis voltage signal and quadrature-axis voltage signal are shown in equation (19); (19) (3) A bandpass filter with a center frequency of twice the switching frequency is used to filter the direct-axis voltage signal and quadrature-axis voltage signal after Park transformation to obtain the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal, and the amplitude of the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal is obtained as the basis for fault judgment.
[0038] The bandpass filter is a digital FIR filter with a bandwidth of [missing information]. , The fundamental frequency has a suppression ratio greater than 30dB.
[0039] (4) Due to the manufacturing and processing of the motor itself, some errors will be introduced into the diagnosis, so a threshold needs to be set. To avoid such interference.
[0040] If the following conditions are met, the permanent magnet synchronous motor is considered to have experienced an inter-turn short circuit fault; otherwise, it is considered that the permanent magnet synchronous motor does not have an inter-turn short circuit fault: .
[0041] in, The amplitude of the characteristic signal of a direct shaft fault. The amplitude of the characteristic signal of the cross-axis fault. This serves as a fault detection threshold.
[0042] Theoretically, the value of can be selected as 0, but due to errors in motor manufacturing processes, it may be greater than 0. In practical applications, it can be designed as the frequency. The motor voltage amplitude coefficient C1 is 10%.
[0043] (5) If an inter-turn short circuit fault occurs, proceed to step (6); otherwise, return to step (1) to continue fault diagnosis. (6) Set the frequency of each phase to be Once the amplitude of the harmonic voltage is extracted, the voltage of the faulty phase will be significantly lower than that of other phases, thus locating the faulty phase.
[0044] The method for locating the faulty phase of a permanent magnet synchronous motor is as follows: Obtain the amplitude values of the three-phase direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal of the permanent magnet synchronous motor, and calculate the sum of the squares of the amplitude values of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, which is denoted as the three-phase direct- and quadrature-axis power. Based on the principle that "the power of the faulty phase's right-angle shaft is significantly lower than the power of the other two phases' right-angle shaft by more than 15%", the faulty phase of the permanent magnet synchronous motor is located.
[0045] This invention has been successfully applied to fault diagnosis of a certain type of motor with good results, and can be further extended to fault diagnosis in other fields.
[0046] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.
Claims
1. A method for diagnosing inter-turn short-circuit faults in a permanent magnet synchronous motor based on switching frequency, characterized in that... Includes the following steps: S1. Real-time acquisition of the three-phase voltage of the permanent magnet synchronous motor. , , and rotational speed ; S2. Extract the three-phase voltage of the permanent magnet synchronous motor. , , The intermediate frequency is Direct-axis fault characteristic signals and quadrature-axis fault characteristic signals; This refers to the switching frequency of the permanent magnet synchronous motor. S3. Based on the amplitude of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, perform inter-turn short-circuit fault diagnosis, provide an indicator of whether the permanent magnet synchronous motor has experienced an inter-turn short-circuit fault, and send it to the fault characteristic location unit; S4. If an inter-turn short circuit fault occurs in the permanent magnet synchronous motor, the faulty phase of the permanent magnet synchronous motor can be located based on the fault characteristic signal extracted from the three-phase voltage of the permanent magnet synchronous motor.
2. The method for diagnosing inter-turn short-circuit faults in a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that... The amplitudes of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal are obtained by the following method: Real-time acquisition of three-phase voltage of permanent magnet synchronous motor , , and rotational speed ; The three-phase voltage of the permanent magnet synchronous motor was collected. , , Conduct based on The Park transform converts the high-frequency negative-sequence components caused by inter-turn short-circuit faults into components with frequencies of 1000-10000. Direct-axis voltage signal and quadrature-axis voltage signal; A bandpass filter with a center frequency of twice the switching frequency is used to filter the Park-transformed direct-axis voltage signal and quadrature-axis voltage signal to obtain the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal, and the amplitude of the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal is obtained.
3. The method for diagnosing inter-turn short-circuit faults in a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that, If the following conditions are met, the permanent magnet synchronous motor is considered to have experienced an inter-turn short circuit fault; otherwise, it is considered that the permanent magnet synchronous motor does not have an inter-turn short circuit fault: 。 in, The amplitude of the characteristic signal of a direct shaft fault. The amplitude of the characteristic signal of the cross-axis fault. This serves as a fault detection threshold.
4. The method for diagnosing inter-turn short-circuit faults in a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that, Fault detection threshold Frequency can be selected The motor voltage amplitude coefficient C1 is 10%.
5. The method for diagnosing inter-turn short-circuit faults in a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that, The method for locating the faulty phase of a permanent magnet synchronous motor is as follows: Obtain the amplitude values of the three-phase direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal of the permanent magnet synchronous motor, and calculate the sum of the squares of the amplitude values of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, which is denoted as the three-phase direct- and quadrature-axis power. Based on the principle that "the power of the faulty phase's right-angle shaft is significantly lower than the power of the other two phases' right-angle shaft by more than 15%", the faulty phase of the permanent magnet synchronous motor is located.
6. A fault diagnosis system for inter-turn short circuits in a permanent magnet synchronous motor based on switching frequency, characterized in that... It includes a fault feature extraction unit and a fault feature localization unit; The fault feature extraction unit collects the three-phase voltage of the permanent magnet synchronous motor. , , and rotational speed The three-phase voltage of a permanent magnet synchronous motor is extracted using the high-frequency negative sequence component method. , , The intermediate frequency is The system identifies the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, and performs inter-turn short-circuit fault diagnosis based on the amplitude of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, providing an indicator of whether the permanent magnet synchronous motor has experienced an inter-turn short-circuit fault, and sends it to the fault characteristic location unit; This refers to the switching frequency of the permanent magnet synchronous motor. The fault feature location unit can locate the faulty phase of the permanent magnet synchronous motor based on the fault feature signals extracted from the three-phase voltage of the permanent magnet synchronous motor if an inter-turn short circuit fault occurs in the permanent magnet synchronous motor.
7. The inter-turn short-circuit fault diagnosis system for permanent magnet synchronous motors according to claim 6, characterized in that, The amplitudes of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal are obtained by the following method: Real-time acquisition of three-phase voltage of permanent magnet synchronous motor , , and rotational speed ; Three-phase voltage of a permanent magnet synchronous motor (PMSM) was collected. , , Conduct based on The Park transform converts the high-frequency negative-sequence components caused by inter-turn short-circuit faults into components with frequencies of 1000-10000. Direct-axis voltage signal and quadrature-axis voltage signal; A bandpass filter with a center frequency of twice the switching frequency is used to filter the Park-transformed direct-axis voltage signal and quadrature-axis voltage signal to obtain the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal, and the amplitude of the direct-axis fault characteristic signal and quadrature-axis fault characteristic signal is obtained.
8. The inter-turn short-circuit fault diagnosis system for a permanent magnet synchronous motor based on switching frequency according to claim 6, characterized in that, If the following conditions are met, the permanent magnet synchronous motor is considered to have experienced an inter-turn short circuit fault; otherwise, it is considered that the permanent magnet synchronous motor does not have an inter-turn short circuit fault: 。 in, The amplitude of the characteristic signal of a direct shaft fault. The amplitude of the characteristic signal of the cross-axis fault. This serves as a fault detection threshold.
9. The inter-turn short-circuit fault diagnosis system for a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that, The bandpass filter is a digital FIR filter with a bandwidth of [missing information]. , The fundamental frequency has a suppression ratio greater than 30dB.
10. The inter-turn short-circuit fault diagnosis system for a permanent magnet synchronous motor based on switching frequency according to claim 1, characterized in that, The method for locating the faulty phase of a permanent magnet synchronous motor is as follows: Obtain the amplitude values of the three-phase direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal of the permanent magnet synchronous motor, and calculate the sum of the squares of the amplitude values of the direct-axis fault characteristic signal and the quadrature-axis fault characteristic signal, which is denoted as the three-phase direct- and quadrature-axis power. Based on the principle that "the power of the faulty phase's right-angle shaft is significantly lower than the power of the other two phases' right-angle shaft by more than 15%", the faulty phase of the permanent magnet synchronous motor is located.