A fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump

Abstract

This invention discloses a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. This device, installed in the permanent magnet synchronous motor drive system, includes: a three-phase voltage and current monitoring module connected to the output terminal of the permanent magnet synchronous motor; a motor speed acquisition module installed on the rotor of the permanent magnet synchronous motor; and fault diagnosis modules for inter-turn short circuit, uniform demagnetization, partial demagnetization, single-tube inverter, and rotary transformer, all located in the motor controller. The permanent magnet synchronous motor drive system equipped with the fault diagnosis device provided in this invention possesses diagnostic capabilities, enabling online calculation and rapid diagnosis, thus providing timely technical support for further troubleshooting and elimination of potential faults.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of fuel control technology, and more specifically to motor control technology, computer technology, electronic hardware technology, embedded software technology, and fault diagnosis technology, particularly to a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. Background Technology

[0002] In recent years, multi-electric / all-electric engines have become a major research focus in aerospace propulsion technology due to their advantages such as simplified structure, high power-to-weight ratio, high maintainability, and high reliability. As a key component of the electric fuel system in aero-engines, the reliability of its control is extremely important.

[0003] The stable operation of the permanent magnet synchronous motor drive system ensures the reliability of the electric fuel pump. If the permanent magnet synchronous motor drive system malfunctions and effective fault diagnosis and handling are not carried out, the electric fuel pump will become uncontrollable, resulting in insufficient fuel flow to the engine and potentially causing engine shutdown.

[0004] Currently, diagnostic schemes for permanent magnet synchronous motor drive systems can generally be divided into three categories: model-based diagnostics, signal-based diagnostics, and knowledge-based diagnostics. Model-based diagnostic schemes often target only a single component, are sensitive to changes in system parameters, and are prone to misdiagnosis. Signal-based diagnostic schemes are computationally complex and time-consuming. Knowledge-based diagnostic schemes require a large amount of historical data, but the limited amount of actual fault data results in poor accuracy of the trained model, thus affecting the final diagnostic results. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems. This invention provides a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. The device addresses the problems in existing fault diagnosis schemes for permanent magnet synchronous motor drive systems, such as the tendency of model-based diagnosis schemes to misdiagnose faults, the long diagnosis time of signal-based diagnosis schemes, and the significant impact of data volume on the diagnostic accuracy of knowledge-based diagnosis schemes.

[0006] The technical solution of the present invention: The present invention provides a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. The permanent magnet synchronous motor drive system includes a permanent magnet synchronous motor and a motor controller. The fault diagnosis device includes: a three-phase voltage and current monitoring module, a motor speed monitoring module, and a fault diagnosis module for inter-turn short circuit of permanent magnet synchronous motor, a fault diagnosis module for uniform demagnetization of permanent magnet synchronous motor, a fault diagnosis module for local demagnetization of permanent magnet synchronous motor, a fault diagnosis module for single tube of inverter, and a fault diagnosis module for rotary transformer, all installed in the motor controller.

[0007] The three-phase voltage and current monitoring module is connected to the output terminal of the permanent magnet synchronous motor and is used to monitor the three-phase voltage and three-phase current of the permanent magnet synchronous motor in the electric fuel pump system, and convert the physical quantities of the three-phase voltage and three-phase current into digital quantities respectively.

[0008] The motor speed acquisition module is installed on the rotor of the permanent magnet synchronous motor and is used to acquire the real-time speed signal of the permanent magnet synchronous motor in the electric fuel pump system. The motor speed acquisition module includes a rotary transformer, which is used to calculate the real-time speed signal of the permanent magnet synchronous motor by acquiring the orthogonal differential signal of the rotary transformer sine or rotary transformer cosine.

[0009] The inter-turn short circuit fault diagnosis module for permanent magnet synchronous motors is used to calculate the characteristic values ​​of inter-turn short circuit faults based on the three-phase voltage and speed signals of the permanent magnet synchronous motor, which serves as the basis for inter-turn short circuit diagnosis.

[0010] The permanent magnet synchronous motor uniform demagnetization fault diagnosis module is used to calculate the uniform demagnetization fault characteristic value based on the three-phase voltage, three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for uniform demagnetization diagnosis.

[0011] The permanent magnet synchronous motor partial demagnetization fault diagnosis module is used to calculate the characteristic values ​​of partial demagnetization fault based on the three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for partial demagnetization diagnosis.

[0012] The inverter single-tube fault diagnosis module is used to calculate the fault characteristic value of the inverter single tube based on the three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for inverter single-tube fault diagnosis.

[0013] The rotary transformer fault diagnosis module is used to calculate the fault characteristic values ​​of the rotary transformer based on the sine-cosine quadrature differential signal output by the rotary transformer, and to serve as the basis for rotary transformer fault diagnosis.

[0014] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the three-phase voltage and current monitoring module includes: a voltage and current acquisition circuit, a voltage and current active filter circuit, an A / D converter, and an SCI communicator connected in sequence.

[0015] The voltage and current acquisition circuit is used to monitor the three-phase current of the permanent magnet synchronous motor and convert the three-phase current into an analog voltage signal that is electrically isolated from the current. The voltage and current acquisition circuit includes: a power supply, a Hall current sensor, an I / V converter, and a voltage follower connected in sequence.

[0016] The power supply is used to power the Hall current sensor.

[0017] The Hall current sensor is used to collect the three-phase current signal of the permanent magnet synchronous motor.

[0018] The I / V converter is used to convert the three-phase current signal output by the Hall current sensor into a three-phase voltage signal;

[0019] The voltage follower is used for impedance matching between the I / V converter and the voltage-current active filter circuit;

[0020] The voltage and current active filtering circuit is used to perform low-pass active filtering on the three-phase voltage signal and three-phase current signal output by the voltage and current acquisition circuit.

[0021] The A / D converter is used to convert the analog quantities of the filtered three-phase voltage signal and the three-phase current signal into digital quantities under the control of the motor controller, so as to obtain the three-phase voltage digital signal and the three-phase current digital signal.

[0022] The SCI communicator is used to transmit three-phase voltage digital signals and three-phase current digital signals to the motor controller via serial communication.

[0023] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the motor speed monitoring module includes: a rotary transformer, an angular velocity acquisition unit, an A / D converter, and an SCI controller connected in sequence.

[0024] The rotary transformer is used to obtain the rotor position angle of the permanent magnet synchronous motor.

[0025] The angular velocity acquisition unit is used to calculate the real-time speed of the motor based on the rotor position angle using its built-in differentiator, and then filters it through the built-in differential low-pass filter.

[0026] An A / D converter is used to convert the output analog signals of rotor position angle and real-time speed into digital signals of motor shaft angle and speed.

[0027] The SCI controller is used to transmit the digital angle signal and digital speed signal of the motor shaft to the motor controller via serial communication.

[0028] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the output end of the permanent magnet synchronous motor is connected to a gear pump, and the gear pump and the permanent magnet synchronous motor drive system constitute an electric fuel pump.

[0029] The permanent magnet synchronous motor inter-turn short circuit fault diagnosis module is used to calculate the negative sequence voltage composite vector of the electric fuel pump based on the three-phase voltage and speed signals of the permanent magnet synchronous motor, which is the characteristic value of the inter-turn short circuit fault and serves as the basis for inter-turn short circuit fault diagnosis. The permanent magnet synchronous motor inter-turn short circuit fault diagnosis module includes: a dq axis positive sequence voltage calculation unit, a dq axis negative sequence voltage calculation unit, and a negative sequence voltage composite vector calculation unit.

[0030] The dq-axis positive sequence voltage calculation unit is used to calculate the three-phase voltage digital signal u output by the three-phase voltage and current acquisition module. a ,u b ,u c The digital speed signal w output by the motor speed monitoring module m , to u in the natural coordinate system a ,u b ,u c Positive sequence voltage transformed to the stationary coordinate system α-β using Clark coordinate transformation for:

[0031]

[0032] Then, the positive sequence voltage in the stationary coordinate system α-β is transformed using Park coordinate transformation. Positive sequence voltage transformed to the dq axis of the synchronous rotating coordinate system for:

[0033]

[0034] Where, θ e θ is the electrical angular velocity, and θ is the digital angle signal output by the motor speed monitoring module. m Multiply by the number of pole pairs n of the permanent magnet synchronous motor p ;

[0035] The dq-axis negative sequence voltage calculation unit is based on a 2ω phase difference between the positive and negative sequence voltage vectors. e Used to convert positive sequence voltage Switch to negative sequence voltage for:

[0036]

[0037] The calculated negative sequence voltage Each filter is then passed through the sliding filter in this unit for filtering.

[0038] The dq-axis negative sequence composite vector calculation unit is used to calculate the negative sequence voltage based on the filtered negative sequence voltage. The characteristic value of inter-turn short-circuit fault is calculated as follows:

[0039] When a surge in characteristic values ​​is detected, it is determined that an inter-turn short circuit fault has occurred in the permanent magnet synchronous motor.

[0040] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump as described above,

[0041] The permanent magnet synchronous motor uniform demagnetization fault diagnosis module establishes a flux linkage observer for the permanent magnet synchronous motor based on the three-phase voltage, three-phase current, and speed signals of the permanent magnet synchronous motor, serving as the basis for uniform demagnetization fault diagnosis. The permanent magnet synchronous motor uniform demagnetization fault diagnosis module includes: a coordinate transformation unit, a back EMF calculation unit, a resistance and inductance estimation unit, a flux linkage observer, and a flux linkage comparator connected in sequence; the coordinate transformation unit is also connected to the back EMF calculation unit.

[0042] The coordinate transformation unit is used to transform the three-phase voltage digital signal and the three-phase current digital signal u output by the three-phase voltage and current acquisition module. a ,u b ,u c i a i b i c and the digital speed signal w output by the motor speed monitoring module. m Calculate the voltage and current u in the stationary coordinate system using Clark transformation. α ,u β i α i β Then, the voltage and current u in the dq axis coordinate system are calculated using the Park transformation. d ,u q i d i q ;

[0043] The resistance and inductance estimation unit is used to add a variable forgetting factor to the least recursive squares algorithm, which can complete the identification of the stator resistance and stator inductance of the permanent magnet synchronous motor. This estimation method improves the accuracy of parameter estimation.

[0044] The back potential calculation unit is used to calculate u based on the coordinate transformation unit. α ,u β i α i β Calculate the back electromotive force using the stator resistance R estimated by the resistance estimation unit:

[0045]

[0046] Where R is the stator resistance of the permanent magnet synchronous motor;

[0047] The flux linkage observer is used to measure the back potential e through an internal integrator.α ,e β Integral calculations are performed to obtain the magnetic flux linkage in the stationary coordinate system. The magnetic flux linkage along the dq axis is obtained after Park transformation. For the calculated dq axis flux A high-pass filter is applied to remove the DC component, and the actual flux linkage of the permanent magnet synchronous motor is calculated as follows: Where Ld is the stator inductance of the permanent magnet synchronous motor output by the resistance and inductance estimation unit;

[0048] The flux linkage comparator is used to obtain the actual flux linkage output by the flux linkage observer. Compared with the pre-calibrated flux linkage value The absolute value of the difference is used as the fault characteristic value; when it is determined that the characteristic value increases sharply, it is determined that the permanent magnet synchronous motor has a uniform demagnetization fault.

[0049] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the permanent magnet synchronous motor partial demagnetization fault diagnosis module is used to calculate the current harmonics based on the three-phase current and speed signals of the permanent magnet synchronous motor, as the basis for diagnosing the partial demagnetization fault; the permanent magnet synchronous motor partial demagnetization fault diagnosis module includes: a harmonic frequency calculation unit and a harmonic current calculation unit connected in series.

[0050] The harmonic frequency calculation unit is used to calculate the harmonic frequencies of fault characteristics contained in the magnetic field of the permanent magnet synchronous motor as follows:

[0051]

[0052] In the formula, f dm f is the harmonic frequency characteristic of the fault. c The fundamental frequency generated by the motor controller, n p Let n be the number of pole pairs of the permanent magnet synchronous motor, and k be the harmonic order, which takes a value less than or equal to n. p Integers;

[0053] The harmonic current calculation unit is used to calculate based on n p The calculated harmonic order k is used to calculate the dq-axis current i through coordinate transformation. d i q Extract i d i q The kth harmonic in the current will cause i d i q The k-th harmonic of a current is converted into a DC component, which is the current harmonic.

[0054]

[0055] The fault characteristics need to be filtered before they can be extracted. An average value filter is used, and the characteristic value of the local demagnetization fault is calculated as follows: If any k-th harmonic of the current increases significantly, a fault is determined to have occurred.

[0056] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the inverter single-tube fault diagnosis module is used to obtain the single-tube fault characteristic value of the three-phase current signal based on the three-phase current signal and speed signal of the permanent magnet synchronous motor; the inverter single-tube fault diagnosis module includes: a Park vector modulus calculation unit, a phase current average value calculation unit, and a phase current average value comparator.

[0057] The Park vector modulus calculation unit is used to process the three-phase current digital signal i output by the three-phase voltage and current acquisition module. a i b i c Calculate the current i in the stationary coordinate system using Clark transformation α i β :

[0058]

[0059] Next, calculate the magnitude of the Clark vector.

[0060] The phase current average value calculation unit is used to calculate the phase current i based on the magnitude of the Clark vector. n The average value of (n = a, b, c) is:

[0061]

[0062] The phase current average value comparator is used to compare the difference between the average value of each phase current and a preset threshold μ. This indicates that the lower tube of the corresponding phase has malfunctioned; This indicates that the upper tube of the corresponding phase has malfunctioned.

[0063] Optionally, in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump described above, the rotary transformer fault diagnosis module includes an amplitude error unit and a phase error unit.

[0064] The amplitude error unit compares the peak value of the envelope of the sine-cosine-orthogonal differential signal output by the rotary transformer with a threshold value. If the peak value of the envelope is less than or greater than the threshold value, it can be determined that the rotary transformer signal is lost and the cause of the fault is a rotary transformer winding fault.

[0065] The phase error unit compares the phase difference β between the excitation signal output from the primary winding of the rotary transformer and the sine-cosine quadrature differential signal output from the two secondary windings of the rotary transformer with a set threshold range. If the phase difference exceeds the threshold range, it is judged as a phase-locking error.

[0066] Beneficial effects of the present invention: The present invention provides a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. The fault diagnosis device is installed in the permanent magnet synchronous motor drive system and includes: a three-phase voltage and current monitoring module connected to the output terminal of the permanent magnet synchronous motor, a motor speed acquisition module installed on the rotor of the permanent magnet synchronous motor, and a fault diagnosis module for inter-turn short circuit of permanent magnet synchronous motor, uniform demagnetization of permanent magnet synchronous motor, local demagnetization of permanent magnet synchronous motor, single tube fault diagnosis module of inverter, and fault diagnosis module of rotary transformer, all installed in the motor controller.

[0067] The fault diagnosis device provided in this embodiment of the invention is mainly used for fault diagnosis of electric fuel systems. Its main function is based on the fault diagnosis function of an intelligent electric fuel pump system, assessing the reliability of various components of the permanent magnet synchronous motor drive system. When a fault occurs, it quickly locates the cause of the fault through a diagnostic strategy. The diagnostic strategy and method can be implemented through an embedded control system, making it an effective means to improve the reliability of the motor drive system. A permanent magnet synchronous motor drive system equipped with the fault diagnosis device provided in this embodiment of the invention possesses diagnostic capabilities, can perform online calculations, and diagnose quickly, thereby promptly detecting faults and providing technical support for further troubleshooting. The fault diagnosis device provided in this embodiment of the invention has the following beneficial effects:

[0068] 1) A fault diagnosis device suitable for permanent magnet synchronous motor drive systems in electric fuel pumps is proposed;

[0069] 2) By acquiring various electrical signals in the electric fuel pump and employing fault diagnosis strategies, various faults in the permanent magnet synchronous motor drive system were effectively diagnosed.

[0070] 3) The diagnostic scope covers permanent magnet synchronous motors, inverters, and rotary transformers in permanent magnet synchronous motor drive systems, and the diagnostic range is relatively wide;

[0071] 4) By using various online fault diagnosis strategies, the cause of the permanent magnet synchronous motor drive system failure can be quickly located, providing a basis for the implementation of subsequent fault-tolerant measures and ensuring the safety of the electric fuel pump. Attached Figure Description

[0072] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0073] Figure 1 A schematic diagram of the structure of a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump provided in an embodiment of the present invention;

[0074] Figure 2 A schematic diagram of the structure of the three-phase voltage and current monitoring module in the fault diagnosis device for the permanent magnet synchronous motor drive system for electric fuel pumps provided in an embodiment of the present invention. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0076] As explained in the background section, the stable operation of the permanent magnet synchronous motor drive system plays a crucial role in ensuring the reliability of the electric fuel pump. However, the three diagnostic schemes currently used for permanent magnet synchronous motor drive systems all have corresponding problems: model-based diagnostic schemes are prone to misdiagnosis of faults, signal-based diagnostic schemes have long diagnostic times, and knowledge-based diagnostic schemes are greatly affected by the amount of data.

[0077] To address the aforementioned problems, this invention provides a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. This device is installed within the permanent magnet synchronous motor drive system, enabling the system to possess diagnostic capabilities. It allows for online calculation and rapid diagnosis, thus promptly identifying faults and providing technical support for further troubleshooting. Furthermore, the technical solution provided in this invention is applicable to the design of electric fuel systems for aero-engines.

[0078] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0079] Figure 1 This is a schematic diagram illustrating the structural relationship between the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump provided in an embodiment of the present invention and the permanent magnet synchronous motor drive system. (See diagram below.) Figure 1 As shown, the permanent magnet synchronous motor drive system includes a permanent magnet synchronous motor and a motor controller; the fault diagnosis device provided in this embodiment of the invention includes: a three-phase voltage and current monitoring module, a motor speed monitoring module, and a permanent magnet synchronous motor inter-turn short circuit fault diagnosis module, a permanent magnet synchronous motor uniform demagnetization fault diagnosis module, a permanent magnet synchronous motor partial demagnetization fault diagnosis module, an inverter single tube fault diagnosis module, and a rotary transformer fault diagnosis module, all set in the motor controller.

[0080] like Figure 1 In the circuit structure of the fault diagnosis device and permanent magnet synchronous motor drive system shown, the three-phase voltage and current monitoring module is connected to the output terminal of the permanent magnet synchronous motor to monitor the three-phase voltage and three-phase current of the permanent magnet synchronous motor in the electric fuel pump system, and convert the physical quantities of the three-phase voltage and three-phase current into digital quantities respectively.

[0081] In this embodiment of the invention, the motor speed acquisition module is installed on the rotor of the permanent magnet synchronous motor and is used to acquire the real-time speed signal of the permanent magnet synchronous motor in the electric fuel pump system. The motor speed acquisition module includes a rotary transformer, which is used to calculate the real-time speed signal of the permanent magnet synchronous motor by acquiring the rotary sine or rotary cosine differential signal.

[0082] It should be noted that the method for obtaining the motor speed by calculating the real-time speed signal from the output signal of the rotary transformer is as follows:

[0083] The resolver output sine and cosine quadrature differential signals are:

[0084]

[0085] Where E is the input amplitude of the primary coil of the rotary transformer, K is the transformation ratio, and n p Let w be the number of pole pairs of the permanent magnet synchronous motor, θ be the rotor angular velocity, and ω be the angular velocity. m The rotor angle is given. The real-time speed signal of the permanent magnet synchronous motor is obtained by using the orthogonal differential signals of the resolver sine and cosine signals, as shown in the following formula:

[0086]

[0087] In this embodiment of the invention, the functions of each module in the motor controller are as follows:

[0088] The inter-turn short circuit fault diagnosis module for permanent magnet synchronous motors is used to calculate the characteristic values ​​of inter-turn short circuit faults based on the three-phase voltage and speed signals of the permanent magnet synchronous motor, which serves as the basis for inter-turn short circuit diagnosis.

[0089] The permanent magnet synchronous motor uniform demagnetization fault diagnosis module is used to calculate the uniform demagnetization fault characteristic value based on the three-phase voltage, three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for uniform demagnetization diagnosis.

[0090] The permanent magnet synchronous motor partial demagnetization fault diagnosis module is used to calculate the characteristic values ​​of partial demagnetization fault based on the three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for partial demagnetization diagnosis.

[0091] The inverter single-tube fault diagnosis module is used to calculate the fault characteristic value of the inverter single tube based on the three-phase current and speed signals of the permanent magnet synchronous motor, and to serve as the basis for inverter single-tube fault diagnosis.

[0092] The rotary transformer fault diagnosis module is used to calculate the fault characteristic values ​​of the rotary transformer based on the sine-cosine quadrature differential signal output by the rotary transformer, and to serve as the basis for rotary transformer fault diagnosis.

[0093] In one implementation of this invention, Figure 2 This is a schematic diagram of the three-phase voltage and current monitoring module in the fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump provided in an embodiment of the present invention. Figure 2 As shown, the three-phase voltage and current monitoring module includes: a voltage and current acquisition circuit, a voltage and current active filter circuit, an A / D converter, and an SCI communicator connected in sequence.

[0094] In this implementation, the voltage and current acquisition circuit is used to monitor the three-phase current of the permanent magnet synchronous motor and convert the three-phase current into an analog voltage signal that is electrically isolated from the current.

[0095] The voltage and current acquisition circuit in this implementation includes: a power supply, a Hall current sensor, an I / V converter, and a voltage follower connected in sequence, such as... Figure 2 As shown.

[0096] The power supply is used to power the Hall current sensor.

[0097] Hall effect current sensors are used to acquire three-phase current signals from permanent magnet synchronous motors.

[0098] An I / V converter is used to convert the three-phase current signal output by the Hall current sensor into a three-phase voltage signal;

[0099] Voltage follower, used for impedance matching between I / V converters and voltage / current active filter circuits;

[0100] The voltage and current active filter circuit is used to perform low-pass active filtering on the three-phase voltage signal and three-phase current signal output by the voltage and current acquisition circuit.

[0101] In addition, the A / D converter in this implementation is used to convert the analog quantities of the filtered three-phase voltage signal and the three-phase current signal into digital quantities under the control of the motor controller, so as to obtain the three-phase voltage digital signal and the three-phase current digital signal.

[0102] The SCI communicator is used to transmit three-phase voltage digital signals and three-phase current digital signals to the motor controller via serial communication.

[0103] In one implementation of this invention, the motor speed monitoring module includes: a rotary transformer, an angular velocity acquisition unit, an A / D converter, and an SCI controller connected in sequence.

[0104] In this implementation, a rotary transformer is used to obtain the rotor position angle of the permanent magnet synchronous motor;

[0105] The angular velocity acquisition unit is used to calculate the real-time speed (i.e., angular velocity) of the motor based on the rotor position angle using its built-in differentiator, and then filters it through the built-in differential low-pass filter.

[0106] An A / D converter is used to convert the output analog signals of rotor position angle and real-time speed into digital signals of motor shaft angle and speed.

[0107] The SCI controller is used to transmit digital signals of motor shaft angle and speed to the motor controller via serial communication.

[0108] In one implementation of this invention, such as Figure 1 As shown, the output end of the permanent magnet synchronous motor is connected to the gear pump, and the gear pump and the permanent magnet synchronous motor drive system constitute an electric fuel pump.

[0109] In this implementation, the inter-turn short circuit fault diagnosis module of the permanent magnet synchronous motor is used to calculate the negative sequence voltage composite vector of the electric fuel pump based on the three-phase voltage and speed signals of the permanent magnet synchronous motor. This vector is the characteristic value of the inter-turn short circuit fault and serves as the basis for inter-turn short circuit fault diagnosis.

[0110] In one implementation scheme of this method, the inter-turn short-circuit fault diagnosis module of the permanent magnet synchronous motor includes: a dq-axis positive sequence voltage calculation unit, a dq-axis negative sequence voltage calculation unit, and a negative sequence voltage synthesis vector calculation unit.

[0111] The dq-axis positive sequence voltage calculation unit is used to calculate the three-phase voltage digital signal u output by the three-phase voltage and current acquisition module. a ,u b ,u c The digital speed signal w output by the motor speed monitoring module m , to u in the natural coordinate system a ,u b ,u c Positive sequence voltage transformed to the stationary coordinate system α-β using Clark coordinate transformation for:

[0112]

[0113] Then, the positive sequence voltage in the stationary coordinate system α-β is transformed using Park coordinate transformation. Positive sequence voltage transformed to the dq axis of the synchronous rotating coordinate system for:

[0114]

[0115] Where, θ e θ is the electrical angular velocity, and θ is the digital angle signal output by the motor speed monitoring module. m Multiply by the number of pole pairs n of the permanent magnet synchronous motor p ;

[0116] The dq-axis negative sequence voltage calculation unit is based on a 2W phase difference between the positive and negative sequence voltage vectors. e Used to convert positive sequence voltage Switch to negative sequence voltage for:

[0117]

[0118] It should be noted that the calculated positive sequence voltage and negative sequence voltage None of them are smooth curves; therefore, the calculated negative sequence voltages need to be processed. The filters are respectively filtered by the sliding filter in the unit; in this embodiment of the invention, the sliding window of the sliding filter is, for example, 50.

[0119] The dq-axis negative sequence composite vector calculation unit is used to calculate the negative sequence voltage based on the filtered negative sequence voltage. The characteristic value of inter-turn short-circuit fault is calculated as follows: Since the fault characteristic value will increase from 0 after the fault occurs, when the characteristic value is detected to surge, it can be determined that the permanent magnet synchronous motor has experienced an inter-turn short circuit fault.

[0120] In one implementation of this invention, a specific embodiment of a uniform demagnetization fault diagnosis module for permanent magnet synchronous motors is provided. This module establishes a flux linkage observer for the permanent magnet synchronous motor based on the three-phase voltage, three-phase current, and speed signals, serving as the basis for uniform demagnetization fault diagnosis. The module comprises: a coordinate transformation unit, a back EMF calculation unit, a resistance / inductance estimation unit, a flux linkage observer, and a flux linkage comparator, connected sequentially. The coordinate transformation unit is also connected to the back EMF calculation unit. The functions of each component are described below.

[0121] The coordinate transformation unit is used to transform the three-phase voltage digital signal and the three-phase current digital signal u output by the three-phase voltage and current acquisition module. a ,u b ,u c i a i b i c and the digital speed signal w output by the motor speed monitoring module. m Calculate the voltage and current u in the stationary coordinate system using Clark transformation.α ,u β i α i β Then, the voltage and current u in the dq axis coordinate system are calculated using the Park transformation. d ,u q i d i q .

[0122] The resistance and inductance estimation unit is used to add a variable forgetting factor to the least recursive squares algorithm, which can identify the stator resistance and stator inductance of the permanent magnet synchronous motor. This estimation method improves the accuracy of parameter estimation.

[0123] The back potential calculation unit is used to calculate u based on the coordinate transformation unit. α ,u β i α i β Calculate the back electromotive force using the stator resistance R estimated by the resistance estimation unit:

[0124]

[0125] Where R is the stator resistance of the permanent magnet synchronous motor.

[0126] A flux linkage observer is used to measure the back potential e via an internal integrator. α ,e β Integral calculations are performed to obtain the magnetic flux linkage in the stationary coordinate system. The magnetic flux linkage along the dq axis is obtained after Park transformation. For the calculated dq axis flux A high-pass filter is applied to remove the DC component, and the actual flux linkage of the permanent magnet synchronous motor is calculated as follows: Among them, L d The output of the resistance and inductance estimation unit is the stator inductance of the permanent magnet synchronous motor.

[0127] A flux comparator is used to measure the actual flux output by the flux observer. Compared with the pre-calibrated flux linkage value The absolute value of the difference is used as the fault characteristic value; when a uniform demagnetization fault occurs, the fault characteristic value increases rapidly; that is, when it is determined that the characteristic value has surged, it is determined that a uniform demagnetization fault has occurred in the permanent magnet synchronous motor.

[0128] In one implementation of this invention, a specific embodiment of a partial demagnetization fault diagnosis module for a permanent magnet synchronous motor is provided. This module is used to calculate current harmonics based on the three-phase current and speed signals of the permanent magnet synchronous motor, serving as the basis for diagnosing partial demagnetization faults. The partial demagnetization fault diagnosis module in this implementation includes: a harmonic frequency calculation unit and a harmonic current calculation unit connected in series. The functions of each unit are described below:

[0129] The harmonic frequency calculation unit is used to calculate the harmonic frequencies of fault characteristics contained in the magnetic field of the permanent magnet synchronous motor.

[0130]

[0131] In the formula, f dm f is the harmonic frequency characteristic of the fault. c The fundamental frequency generated by the motor controller, n p Let n be the number of pole pairs of the permanent magnet synchronous motor, and k be the harmonic order, which takes a value less than or equal to n. p The integer; the harmonic frequency calculation unit is based on the harmonic frequency calculation formula to obtain k.

[0132] The harmonic current calculation unit is used to calculate the harmonic current based on n. p The calculated harmonic order k is used to calculate the dq-axis current i through coordinate transformation. d i q Extract i d i q The kth harmonic in the current will cause i d i q The k-th harmonic of a current is converted into a DC component, which is the current harmonic.

[0133]

[0134] The fault characteristics need to be filtered before they can be extracted. An average value filter is used, and the characteristic value of the local demagnetization fault is calculated as follows: If any k-th harmonic of the current increases significantly, a fault is determined to have occurred.

[0135] In one implementation of this invention, a specific embodiment of a single-transistor fault diagnosis module for an inverter is provided. This module is used to calculate the single-transistor fault characteristic value of the three-phase current signal based on the three-phase current signal and speed signal of the permanent magnet synchronous motor. The single-transistor fault diagnosis module in this implementation includes: a Park vector modulus calculation unit, a phase current average value calculation unit, and a phase current average value comparator. The functions of each component are described below:

[0136] The Park vector's modulus calculation unit is used to process the three-phase current digital signal i output by the three-phase voltage and current acquisition module. a i b i c Calculate the current i in the stationary coordinate system using Clark transformation α i β :

[0137]

[0138] Next, calculate the magnitude of the Clark vector.

[0139] The phase current average value calculation unit is used to calculate the phase current i based on the magnitude of the Clark vector. n The average value of (n = a, b, c) is:

[0140]

[0141] A phase current average value comparator is used because the average phase current is 0 within one cycle. When a single-tube fault occurs, the average phase current surges, triggering a threshold μ. Therefore, this phase current average value comparator compares the difference between the average phase current and the preset threshold μ. This indicates that the lower tube of the corresponding phase has malfunctioned; This indicates that the upper tube of the corresponding phase has malfunctioned.

[0142] In one implementation of the present invention, a specific implementation scheme for a rotary transformer fault diagnosis module is provided, which includes an amplitude error unit and a phase error unit.

[0143] In this implementation, the amplitude error unit compares the peak value of the envelope of the sine-cosine orthogonal differential signal output by the resolver with a set threshold. If the peak value of the envelope is less than or greater than the threshold, it can be determined that the resolver signal is lost and the cause of the fault is a resolver winding fault.

[0144] In this implementation, the phase error unit compares the phase difference β between the excitation signal output from the primary winding of the rotary transformer and the sine-cosine quadrature differential signal output from the two secondary windings of the rotary transformer with a set threshold range. If the phase difference exceeds the threshold range, it is judged as a phase-locked error.

[0145] The present invention provides a fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump. The fault diagnosis device is installed in the permanent magnet synchronous motor drive system and includes: a three-phase voltage and current monitoring module connected to the output terminal of the permanent magnet synchronous motor, a motor speed acquisition module installed on the rotor of the permanent magnet synchronous motor, and a fault diagnosis module for inter-turn short circuit of permanent magnet synchronous motor, uniform demagnetization of permanent magnet synchronous motor, local demagnetization of permanent magnet synchronous motor, single tube fault diagnosis module of inverter, and fault diagnosis module of rotary transformer, all installed in the motor controller.

[0146] The fault diagnosis device provided in this embodiment of the invention is mainly used for fault diagnosis of electric fuel systems. Its main function is based on the fault diagnosis function of an intelligent electric fuel pump system, assessing the reliability of various components of the permanent magnet synchronous motor drive system. When a fault occurs, it quickly locates the cause of the fault through a diagnostic strategy. The diagnostic strategy and method can be implemented through an embedded control system, making it an effective means to improve the reliability of the motor drive system. A permanent magnet synchronous motor drive system equipped with the fault diagnosis device provided in this embodiment of the invention possesses diagnostic capabilities, can perform online calculations, and diagnose quickly, thereby promptly detecting faults and providing technical support for further troubleshooting. The fault diagnosis device provided in this embodiment of the invention has the following beneficial effects:

[0147] 1) A fault diagnosis device suitable for permanent magnet synchronous motor drive systems in electric fuel pumps is proposed;

[0148] 2) By acquiring various electrical signals in the electric fuel pump and employing fault diagnosis strategies, various faults in the permanent magnet synchronous motor drive system were effectively diagnosed.

[0149] 3) The diagnostic scope covers permanent magnet synchronous motors, inverters, and rotary transformers in permanent magnet synchronous motor drive systems, and the diagnostic range is relatively wide;

[0150] 4) By using various online fault diagnosis strategies, the cause of the permanent magnet synchronous motor drive system failure can be quickly located, providing a basis for the implementation of subsequent fault-tolerant measures and ensuring the safety of the electric fuel pump.

[0151] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A fault diagnosis device for a permanent magnet synchronous motor drive system for an electric fuel pump, characterized in that, The permanent magnet synchronous motor drive system includes a permanent magnet synchronous motor and a motor controller; the fault diagnosis device includes: a three-phase voltage and current monitoring module, a motor speed monitoring module, and a permanent magnet synchronous motor inter-turn short circuit fault diagnosis module, a permanent magnet synchronous motor uniform demagnetization fault diagnosis module, a permanent magnet synchronous motor partial demagnetization fault diagnosis module, an inverter single tube fault diagnosis module, and a rotary transformer fault diagnosis module, all installed in the motor controller. The three-phase voltage and current monitoring module is connected to the output terminal of the permanent magnet synchronous motor and is used to monitor the three-phase voltage and three-phase current of the permanent magnet synchronous motor in the electric fuel pump system, and convert the physical quantities of the three-phase voltage and three-phase current into digital quantities respectively. The motor speed acquisition module is installed on the rotor of the permanent magnet synchronous motor and is used to acquire the real-time speed signal of the permanent magnet synchronous motor in the electric fuel pump system. The motor speed acquisition module includes a rotary transformer, which is used to calculate the real-time speed signal of the permanent magnet synchronous motor by acquiring the orthogonal differential signal of the rotary transformer sine or rotary transformer cosine. The inter-turn short-circuit fault diagnosis module for permanent magnet synchronous motors is used to calculate the characteristic values ​​of inter-turn short-circuit faults based on the three-phase voltage and speed signals of the permanent magnet synchronous motor, serving as the basis for inter-turn short-circuit fault diagnosis; the characteristic values ​​of the inter-turn short-circuit faults are: ,in, This is the filtered negative sequence voltage; The uniform demagnetization fault diagnosis module for permanent magnet synchronous motors is used to calculate uniform demagnetization fault characteristic values ​​based on the three-phase voltage, three-phase current, and speed signals of the permanent magnet synchronous motor, serving as the basis for uniform demagnetization diagnosis; the uniform demagnetization fault characteristic value is the actual flux linkage of the permanent magnet synchronous motor. Compared with the pre-calibrated flux linkage value The absolute value of the difference; The permanent magnet synchronous motor partial demagnetization fault diagnosis module is used to calculate the characteristic values ​​of partial demagnetization faults based on the three-phase current and speed signals of the permanent magnet synchronous motor, serving as the basis for partial demagnetization fault diagnosis; the characteristic values ​​of the partial demagnetization faults are: ,in, dq axis current The DC component obtained by converting the kth harmonic is the current harmonic. The inverter single-transistor fault diagnosis module is used to calculate the fault characteristic value of the inverter single transistor based on the three-phase current and speed signals of the permanent magnet synchronous motor, serving as the basis for single-transistor fault diagnosis; the single-transistor fault characteristic value is the average value of the phase current of the permanent magnet synchronous motor. With preset threshold The difference between The rotary transformer fault diagnosis module is used to calculate the fault characteristic values ​​of the rotary transformer based on the orthogonal differential signal output by the rotary transformer, and to serve as the basis for rotary transformer fault diagnosis. The rotary transformer fault diagnosis module includes an amplitude error unit and a phase error unit; The amplitude error unit compares the peak value of the envelope of the sine-cosine-orthogonal differential signal output by the rotary transformer with a threshold value. If the peak value of the envelope is less than or greater than the threshold value, it can be determined that the rotary transformer signal is lost and the cause of the fault is a rotary transformer winding fault. The phase error unit is based on the phase difference between the excitation signal output from the primary winding of the rotary transformer and the sine-cosine quadrature differential signals output from the two secondary windings of the rotary transformer. The value is compared with the set threshold range; if it exceeds the threshold range, it is judged as a phase-locked error.

2. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 1, characterized in that, The three-phase voltage and current monitoring module includes: a voltage and current acquisition circuit, a voltage and current active filter circuit, an A / D converter, and an SCI communicator connected in sequence. The voltage and current acquisition circuit is used to monitor the three-phase current of the permanent magnet synchronous motor and convert the three-phase current into an analog voltage signal that is electrically isolated from the current. The voltage and current acquisition circuit includes: a power supply, a Hall current sensor, an I / V converter, and a voltage follower connected in sequence. The power supply is used to power the Hall current sensor. The Hall current sensor is used to collect the three-phase current signal of the permanent magnet synchronous motor. The I / V converter is used to convert the three-phase current signal output by the Hall current sensor into a three-phase voltage signal; The voltage follower is used for impedance matching between the I / V converter and the voltage-current active filter circuit; The voltage and current active filtering circuit is used to perform low-pass active filtering on the three-phase voltage signal and three-phase current signal output by the voltage and current acquisition circuit. The A / D converter is used to convert the analog quantities of the filtered three-phase voltage signal and the three-phase current signal into digital quantities under the control of the motor controller, so as to obtain the three-phase voltage digital signal and the three-phase current digital signal. The SCI communicator is used to transmit three-phase voltage digital signals and three-phase current digital signals to the motor controller via serial communication.

3. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 1, characterized in that, The motor speed monitoring module includes: a rotary transformer, an angular velocity acquisition unit, an A / D converter, and an SCI controller connected in sequence; The rotary transformer is used to obtain the rotor position angle of the permanent magnet synchronous motor. The angular velocity acquisition unit is used to calculate the real-time speed of the motor based on the rotor position angle using its built-in differentiator, and then filters it through the built-in differential low-pass filter. An A / D converter is used to convert the output analog signals of rotor position angle and real-time speed into digital signals of motor shaft angle and speed. The SCI controller is used to transmit the digital angle signal and digital speed signal of the motor shaft to the motor controller via serial communication.

4. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 3, characterized in that, The output end of the permanent magnet synchronous motor is connected to the gear pump, and the gear pump and the permanent magnet synchronous motor drive system constitute an electric fuel pump. The permanent magnet synchronous motor inter-turn short circuit fault diagnosis module is used to calculate the negative sequence voltage composite vector of the electric fuel pump based on the three-phase voltage and speed signals of the permanent magnet synchronous motor, which is the inter-turn short circuit fault characteristic value, and serves as the basis for inter-turn short circuit fault diagnosis. The permanent magnet synchronous motor inter-turn short circuit fault diagnosis module includes: a dq axis positive sequence voltage calculation unit, a dq axis negative sequence voltage calculation unit, and a negative sequence voltage composite vector calculation unit; The dq-axis positive sequence voltage calculation unit is used to calculate the three-phase voltage digital signal output by the three-phase voltage and current acquisition module. The digital speed signal output by the motor speed monitoring module , in the natural coordinate system Transform to the stationary coordinate system using Clark coordinate transformation. Positive sequence voltage , for: ； Then, the stationary coordinate system is transformed using Park coordinate transformation. Positive sequence voltage , Positive sequence voltage transformed to the d-q axis of a synchronous rotating coordinate system , for: ； in, The electric angular velocity is the digital angle signal output by the motor speed monitoring module. Multiply by the number of pole pairs of the permanent magnet synchronous motor ; The dq-axis negative sequence voltage calculation unit is based on the phase difference between the positive and negative sequence voltage vectors. Used to convert positive sequence voltage Switch to negative sequence voltage for: ； The calculated negative sequence voltage Each filter is then passed through the sliding filter in this unit for filtering. The dq-axis negative sequence composite vector calculation unit is used to calculate the negative sequence voltage based on the filtered negative sequence voltage. The characteristic value of inter-turn short-circuit fault is calculated as follows: ; When a surge in characteristic values ​​is detected, it is determined that an inter-turn short circuit fault has occurred in the permanent magnet synchronous motor.

5. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 3, characterized in that, The permanent magnet synchronous motor uniform demagnetization fault diagnosis module establishes a flux linkage observer for the permanent magnet synchronous motor based on the three-phase voltage, three-phase current, and speed signals of the permanent magnet synchronous motor, serving as the basis for uniform demagnetization fault diagnosis. The permanent magnet synchronous motor uniform demagnetization fault diagnosis module includes: a coordinate transformation unit, a back EMF calculation unit, a resistance and inductance estimation unit, a flux linkage observer, and a flux linkage comparator connected in sequence; the coordinate transformation unit is also connected to the back EMF calculation unit. The coordinate transformation unit is used to transform the three-phase voltage digital signal and the three-phase current digital signal output by the three-phase voltage and current acquisition module. and the digital speed signal output by the motor speed monitoring module. Calculate voltage and current in stationary coordinates using Clark transformation. Then, the voltage and current in the dq axis coordinate system are calculated using the Park transformation. ; The resistance and inductance estimation unit is used to add a variable forgetting factor to the least recursive squares algorithm, which can complete the identification of the stator resistance and stator inductance of the permanent magnet synchronous motor. This estimation method improves the accuracy of parameter estimation. The back potential calculation unit is used to calculate the value obtained by the coordinate transformation unit. Calculate the back electromotive force using the stator resistance R estimated by the resistance estimation unit: ； Where R is the stator resistance of the permanent magnet synchronous motor; The magnetic flux observer is used to measure the back potential through an internal integrator. Integral calculations are performed to obtain the magnetic flux linkage in the stationary coordinate system. The dq-axis flux linkage is obtained after Park transformation. For the calculated dq axis flux A high-pass filter is applied to remove the DC component, and the actual flux linkage of the permanent magnet synchronous motor is calculated. Where Ld is the stator inductance of the permanent magnet synchronous motor output by the resistance and inductance estimation unit; The flux linkage comparator is used to obtain the actual flux linkage output by the flux linkage observer. Compared with the pre-calibrated flux linkage value The absolute value of the difference is used as the fault characteristic value; when it is determined that the characteristic value increases sharply, it is determined that the permanent magnet synchronous motor has a uniform demagnetization fault.

6. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 3, characterized in that, The permanent magnet synchronous motor partial demagnetization fault diagnosis module is used to calculate current harmonics based on the three-phase current and speed signals of the permanent magnet synchronous motor, as the basis for diagnosing partial demagnetization faults; the permanent magnet synchronous motor partial demagnetization fault diagnosis module includes: a harmonic frequency calculation unit and a harmonic current calculation unit connected in series. The harmonic frequency calculation unit is used to calculate the harmonic frequencies of fault characteristics contained in the magnetic field of the permanent magnet synchronous motor as follows: ； Where, The harmonic frequencies characteristic of the fault. The fundamental frequency generated by the motor controller. Let k be the number of pole pairs of the permanent magnet synchronous motor, and k be the harmonic order, with a value less than or equal to 1. Integers; The harmonic current calculation unit is used to calculate based on The calculated harmonic order k is used to calculate the dq-axis current through coordinate transformation. Extracting dq-axis current The k-th harmonic in the middle will affect the dq-axis current. The kth harmonic is converted into a DC component, which is the current harmonic; ； The fault characteristics need to be filtered before they can be extracted. An average value filter is used, and the characteristic value of the local demagnetization fault is calculated as follows: If any k-th harmonic of the current increases significantly, a fault is determined to have occurred.

7. The fault diagnosis device for the permanent magnet synchronous motor drive system of the electric fuel pump according to claim 3, characterized in that, The inverter single-tube fault diagnosis module is used to obtain the single-tube fault characteristic value of the three-phase current signal based on the three-phase current signal and speed signal of the permanent magnet synchronous motor. The inverter single-tube fault diagnosis module includes: a Park vector modulus calculation unit, a phase current average value calculation unit, and a phase current average value comparator. The Park vector modulus calculation unit is used to process the three-phase current digital signal output by the three-phase voltage and current acquisition module. Calculate the current in the stationary coordinate system using Clark transformation : ； Next, calculate the magnitude of the Clark vector. ; The phase current average value calculation unit is used to calculate the phase current based on the magnitude of the Clark vector. The average value is: ； ； The phase current average value comparator is used to compare the average value of each phase current with a preset threshold. The difference, when If so, it can be determined that the lower tube of the corresponding phase has failed; If so, it can be determined that the upper tube of the corresponding phase has failed.

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