Online resistance identification method for high-resistance contact fault of multi-phase permanent magnet synchronous motor

Abstract

The invention provides an online resistance identification method for a high-resistance contact fault of a multi-phase permanent magnet synchronous motor, and relates to the technical field of fault-tolerant control of a multi-phase motor. The method comprises the steps of determining a fault phase position where a high-resistance contact fault occurs, selecting a corresponding compensation coefficient matrix, calculating a corresponding fault correction coefficient matrix according to the compensation coefficient matrix in combination with stator current and a coordinate transformation matrix, and extracting a fault correction coefficient; obtaining a fault state mathematical model expansion equation set considering neutral point offset under the rotating coordinate system, selecting at least one voltage equation in the expansion equation set as a target equation, and determining an online resistance identification model satisfying a recursive least square method based on the target equation; and inputting the stator voltage, the stator current, the electrical angular velocity and the fault correction coefficient under the corresponding rotating coordinate system in the target equation into an online resistance identification model to obtain a resistance matrix. According to the method, the high-resistance contact resistance and the stator resistance can be identified in real time, and the fault-tolerant control algorithm performance is improved.

Description

Technical Field

[0001] This application relates to the technical field of fault-tolerant control of multiphase motors, and particularly to an online resistance identification method for high-resistance contact faults in multiphase permanent magnet synchronous motors. Background Art

[0002] Multiphase permanent magnet synchronous motors are widely used in many fields due to their high power density, low torque ripple, and strong fault-tolerant ability, but they are vulnerable to high-resistance contact faults. High-resistance contact faults are caused by factors such as manufacturing defects, thermal stress, vibration, or oxidation of the contact surface, resulting in unbalanced stator current and voltage, increased local temperature rise, reduced average torque, increased losses and heat in multiphase permanent magnet synchronous motors, seriously deteriorating the operating performance of multiphase permanent magnet synchronous motors, and even damaging the multiphase permanent magnet synchronous motor drive system.

[0003] The fault-tolerant control algorithms in the related art are based on fixed contact resistance parameters, but the resistance value of the contact resistance is affected by temperature, oxidation corrosion, mechanical stress, etc., showing dynamic time-varying characteristics, resulting in limited performance and accuracy of the control algorithm. The online parameter identification method either cannot adapt to the voltage and current imbalance in the fault state based on the voltage equation, or uses the high-frequency signal injection method, resulting in torque and speed fluctuations and increased losses, further deteriorating the performance of multiphase permanent magnet synchronous motors. Summary of the Invention

[0004] Based on this, it is necessary to provide an online resistance identification method and system for high-resistance contact faults in multiphase permanent magnet synchronous motors in view of the above technical problems. This method can identify the high-resistance contact resistance and stator resistance in real time and improve the performance of the fault-tolerant control algorithm.

[0005] In the first aspect, this application provides an online resistance identification method for high-resistance contact faults in multiphase permanent magnet synchronous motors. The method includes: In response to a high-resistance contact fault in a multiphase permanent magnet synchronous motor, determining the position of the faulty phase where the high-resistance contact fault occurs; the position of the faulty phase is any phase of the multiphase permanent magnet synchronous motor; According to the position of the faulty phase, selecting the corresponding compensation coefficient matrix , and the compensation coefficient matrix is the matrix when a high-resistance contact fault occurs in the phase of the multiphase permanent magnet synchronous motor; According to the compensation coefficient matrix , combining the stator current and the coordinate transformation matrix, calculating the corresponding fault correction coefficient matrix , and extracting the fault correction coefficient from the fault correction coefficient matrix ; the fault correction coefficient is the th The element corresponding to the first column of the row represents the polyphase permanent magnet synchronous motor when a high-resistance contact fault occurs in a phase the fault correction coefficient of the voltage equation corresponding to the axis; Obtain the expanded equations of the fault state mathematical model of the polyphase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system; the expanded equations of the fault state mathematical model include the voltage equation corresponding to the axis; the voltage equation is in the rotating coordinate system the equation related to the stator voltage, stator current, electrical angular velocity, motor parameters and high-resistance contact resistance corresponding to the axis; Select at least one voltage equation in the expanded equations of the fault state mathematical model as the target equation, and determine an online resistance identification model that satisfies the recursive least squares method based on the target equation; Obtain the stator voltage, stator current and electrical angular velocity of the axis corresponding to the target equation, and combine the stator voltage, stator current, electrical angular velocity and the fault correction coefficient Input into the online resistance identification model to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

[0006] In one embodiment, obtaining the expanded equations of the fault state mathematical model of the polyphase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system includes: Construct an initial fault state model of the polyphase permanent magnet synchronous motor in the natural coordinate system; Based on the offset of the neutral point of the polyphase permanent magnet synchronous motor, determine the neutral point voltage matrix of the polyphase permanent magnet synchronous motor, and the neutral point voltage matrix is the neutral point-to-ground voltage matrix; Based on the neutral point voltage matrix and the initial fault state model, determine the expanded equations of the fault state model.

[0007] In one embodiment, based on the neutral point voltage matrix and the initial fault state model, determining the expanded equations of the fault state mathematical model includes: Based on the neutral point voltage matrix and the initial fault state mathematical model, construct a transitional fault state mathematical model of the polyphase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system; Based on the transitional fault state mathematical model and the coordinate transformation matrix 、 , construct a fault state mathematical model of the polyphase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system; Based on the fault state mathematical model, determine the expanded equations of the fault state mathematical model.

[0008] The expression of the transitional fault state mathematical model of the polyphase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system is: ; Among them, is the number of phases of the multiphase permanent magnet synchronous motor, is the neutral point voltage matrix to the ground when the faulty phase is phase, is the faulty phase current when the faulty phase is phase, is the high resistance contact resistance when the faulty phase is phase.

[0009] The expression of the fault state transition mathematical model of the multiphase permanent magnet synchronous motor considering neutral point shift in the natural coordinate system is: ; Among them, represents the terminal voltage matrix of the fault state multiphase permanent magnet synchronous motor; represents the phase current matrix of the fault state multiphase permanent magnet synchronous motor; is the stator resistance matrix, , is the stator resistance, is identity matrix; is the matrix composed of the high resistance contact resistance and the identity matrix, ; is the compensation coefficient matrix when the faulty phase is phase; is the stator flux linkage matrix, , is the stator inductance matrix, is the permanent magnet flux linkage matrix, represents the differential symbol.

[0010] In one of the embodiments, the expression of the fault state mathematical model is: ; ; Among them, is the fault state voltage matrix in the rotating coordinate system; is the fault state current matrix in the rotating coordinate system; and are the coordinate transformation matrices; is the flux linkage matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux linkage matrix in the rotating coordinate system; is the electrical angular velocity matrix in the rotating coordinate system; is the fault correction coefficient matrix when the faulty phase is phase, is the fault correction coefficient matrix The element corresponding to the first column of the row represents the fault correction coefficient of the voltage equation corresponding to the axis when a high-resistance contact fault occurs in the

[0011] In one embodiment, the expression of the expansion equation of the fault-state mathematical model is: ; wherein represents the electrical angular velocity of the multi-phase permanent magnet synchronous motor, respectively represent the stator voltages on the axis in the rotating coordinate system, is the stator current on the axis in the rotating coordinate system, , , … are the permanent magnet flux linkages of the k th harmonic subspace, is the inductance on the axis in the rotating coordinate system.

[0012] In one embodiment, select the voltage equation corresponding to the axis in the rotating coordinate system in the expansion equation set of the fault-state mathematical model as the target equation; Obtain the stator voltage, stator current, electrical angular velocity, and fault correction coefficient corresponding to the target equation Input into the online resistance identification model to obtain the resistance matrix as: Obtain the stator voltage corresponding to the , stator current and electrical angular velocity , and input the stator voltage , electronic current , electrical angular velocity and fault correction coefficient into the online resistance identification model to obtain the resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

[0013] In one embodiment, the expression of the online resistance identification model includes the input matrix of the online resistance identification model, the coefficient matrix of the online resistance identification model, and the output of the online resistance identification model; wherein, the expression of the online resistance identification model is: , represents the output of the online resistance identification model, represents the input matrix of the online resistance identification model, represents the coefficient matrix of the online resistance identification model, and the coefficient matrix of the online resistance identification model is equal to the resistance matrix; wherein, , , .

[0014] In a second aspect, the present application also provides an online resistance identification system for high-resistance contact faults of a multiphase permanent magnet synchronous motor. The system includes a multiphase permanent magnet synchronous motor and a controller, and the controller can execute the online resistance identification method for high-resistance contact faults of the multiphase permanent magnet synchronous motor in the first aspect.

[0015] The above-mentioned online identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor. The method responds to the high-resistance contact fault of the multiphase permanent magnet synchronous motor, determines the position of the faulty phase, selects the corresponding compensation coefficient matrix according to the position of the faulty phase, and combines the stator current and the coordinate transformation matrix to calculate the fault correction coefficient matrix, and extracts the fault correction coefficient from the fault correction coefficient matrix. Further, obtain the expanded equations of the fault state mathematical model considering neutral point offset, select a suitable voltage equation as the target equation, and construct an online resistance identification model that satisfies the recursive least squares method. Input the stator voltage, stator current, electrical angular velocity, and fault correction coefficient in the rotating coordinate system into the online resistance identification model to obtain a resistance matrix including the stator resistance and the high-resistance contact resistance of the faulty phase. This method can identify the high-resistance contact resistance and the stator resistance in real time, improve the performance of the fault-tolerant control algorithm, and ensure the reliability and safety of the multiphase permanent magnet synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flowchart of an online resistance identification method for high-resistance contact of a multiphase permanent magnet synchronous motor in an embodiment; Figure 2 is a flowchart of obtaining the expanded equations of the fault state mathematical model considering neutral point offset of a multiphase permanent magnet synchronous motor in the rotating coordinate system in an embodiment; Figure 3 is a flowchart of determining the expanded equations of the fault state mathematical model based on the neutral point voltage matrix and the initial fault state model in an embodiment; Figure 4 is a vector control block diagram of a five-phase permanent magnet synchronous motor in an embodiment; Figure 5 is a schematic diagram of coordinate transformation of a five-phase permanent magnet synchronous motor in an embodiment; Figure 6 is a schematic diagram of a single-phase high-resistance contact fault of a five-phase permanent magnet synchronous motor in an embodiment; Figure 7 In an embodiment, when a high-resistance contact fault occurs in the phase, it is a simulation result diagram of the identification of the high-resistance contact resistance and the stator resistance. Detailed implementation manners

[0017] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] In one embodiment, as Figure 1 shown, an online resistance identification method for high-resistance contact of a multi-phase permanent magnet synchronous motor is provided, and the method includes the following steps: Step 101: In response to a high-resistance contact fault of a multi-phase synchronous motor, determine the position of the faulty phase where the high-resistance contact occurs; the position of the faulty phase is any phase of the multi-phase permanent magnet synchronous motor; Exemplarily, taking a permanent magnet five-phase synchronous motor as an example, the five-phase synchronous motor has five phases (for example five phases), and these phases are symmetrically distributed in the five-phase synchronous motor to jointly drive the operation of the five-phase synchronous motor. It should be noted that, in order to more clearly elaborate the technical solution hereinafter, the permanent magnet five-phase synchronous motor will be taken as an example in the subsequent specific implementation manners, that is, the appearing in the subsequent embodiments is specifically , for example, the compensation coefficient matrix is , the fault correction coefficient matrix is and is the identity matrix specifically corresponding to is the identity matrix, etc. It should be further noted that in the subsequent specific implementation manners, the axis of the rotating coordinate system will be simplified to the axis.

[0019] It should be noted that the high-resistance contact fault refers to a significant increase in the contact resistance between the winding of a certain phase of the multi-phase synchronous motor and the neutral point or ground of the multi-phase permanent magnet synchronous motor, which may be caused by manufacturing defects, thermal stress, vibration or contact surface oxidation, etc. The phase where the high-resistance contact fault occurs usually exhibits the characteristics of increased voltage and decreased current, and causes the neutral point voltage of the multi-phase permanent magnet synchronous motor to shift, thereby affecting the performance of the entire multi-phase permanent magnet synchronous motor.

[0020] Step 102: Select the corresponding compensation coefficient matrix according to the position of the faulty phase. The compensation coefficient matrix is the matrix when a high-resistance contact fault occurs in the phase of the multi-phase permanent magnet synchronous motor; When it is detected that a certain phase ( When a high-resistance contact fault occurs in a certain phase ( phase), a compensation coefficient matrix corresponding to the position of this fault phase is selected. . Among them, the compensation coefficient matrix is a square matrix, which is used to characterize the impact on the overall performance of the multi-phase permanent magnet synchronous motor when a high-resistance contact fault occurs in a certain phase of the multi-phase permanent magnet synchronous motor. The compensation coefficient matrix can adjust the voltage and current distribution of each phase to compensate for the performance changes caused by the fault phase.

[0021] It should be noted that the parameters of the compensation coefficient matrix are determined in advance according to the design characteristics and fault modes of the multi-phase permanent magnet synchronous motor. Once the position of the fault phase is determined, the corresponding compensation coefficient matrix is called to realize the real-time adjustment of the voltage equation of the multi-phase permanent magnet synchronous motor.

[0022] Step 103: Calculate the corresponding fault correction coefficient matrix by combining the stator current and the coordinate transformation matrix according to the compensation coefficient matrix . The fault correction coefficient matrix is a matrix. Extract the fault correction coefficient from the fault correction coefficient matrix ; is the element corresponding to the first column of the th row of the fault correction coefficient matrix, indicating the fault correction coefficient of the voltage equation corresponding to the axis of the multi-phase permanent magnet synchronous motor when a high-resistance contact fault occurs in the phase.

[0023] If it is determined that a high-resistance contact fault occurs in a certain phase ( phase), based on the compensation coefficient matrix corresponding to this fault phase, calculate the fault correction coefficient matrix corresponding to this fault phase by combining the stator current and the coordinate transformation matrix. Extract the fault correction coefficient from the fault correction coefficient matrix . The fault correction coefficient is the element corresponding to the first column of the th row of the fault correction coefficient matrix, indicating the fault correction coefficient of the voltage equation corresponding to the axis of the multi-phase permanent magnet synchronous motor when a high-resistance contact fault occurs in the phase. The fault correction coefficient can be used to adjust the voltage equations of different coordinate axes of the fault phase in the rotating coordinate system to reflect the impact of the fault on the performance of the multi-phase permanent magnet synchronous motor.

[0024] Exemplarily, taking a five-phase permanent magnet synchronous motor as an example, in a five-phase permanent magnet synchronous motor, if a high-resistance contact fault occurs in a phase, then the corresponding compensation coefficient matrix will be selected. According to the fault phase the corresponding compensation coefficient matrix combined with the current stator current and the coordinate transformation matrix, the corresponding fault correction coefficient matrix can be calculated. Extract the fault correction coefficient from the fault correction coefficient matrix The fault correction coefficient is the element corresponding to the first column of the th row of the fault correction coefficient matrix, indicating the fault correction coefficient of the voltage equation corresponding to the axis when a high-resistance contact fault occurs in the

[0025] Step 104: Obtain the expanded equations of the fault state mathematical model of the multi-phase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system; the expanded equations of the fault state mathematical model include the voltage equation corresponding to the axis; the voltage equation is an equation related to the stator voltage, stator current, electrical angular velocity, motor parameters and high-resistance contact resistance in the rotating coordinate system Obtaining the expanded equations of the fault state mathematical model considering neutral point offset in the rotating coordinate system involves converting the fault state mathematical model of the motor in the natural coordinate system to the fault state mathematical model in the rotating coordinate system and considering the influence of neutral point offset. The expanded equations of the fault state mathematical model specifically include the voltage equations corresponding to the

[0026] axis, and the voltage equation of each axis can describe how the stator voltage on the corresponding axis is comprehensively affected by the high-resistance contact resistance, motor parameters, electrical angular velocity and stator current. Among them, the motor parameters are at least one of the stator resistance, the nominal value of the magnetic flux, and the inductance. Exemplarily, the voltage equation corresponding to the axis can be selected as the target equation. After selecting the voltage equation of the The voltage equation of the axis is algebraically transformed to be expressed as a linear relationship between the output variables, input variables, and parameters to be identified of the fault-state mathematical model.

[0027] It should be noted that in the process of online resistance identification, selecting a model that satisfies the recursive least squares method is to achieve the optimal estimation of parameters. The core principle of the recursive least squares method is to solve the unknown parameters by minimizing the sum of the squares of the residuals between the observed values and the model predicted values. In online resistance identification, the recursive least squares method can effectively handle multivariable linear regression problems, provide unbiased estimation, and has low computational complexity and is easy to apply in real time, enabling the multiphase permanent magnet synchronous motor to achieve accurate resistance parameter estimation after a fault occurs.

[0028] Step 106: Obtain the stator voltage, stator current, and electrical angular velocity of the axis, and input the stator voltage, stator current, electrical angular velocity, and fault correction coefficient into the online resistance identification model to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

[0029] Obtain the stator voltage, stator current, and electrical angular velocity corresponding to the target equation. Among them, the sensors of the multiphase permanent magnet synchronous motor can measure the corresponding voltage and current of each phase in the natural coordinate system in real time, and the voltage and current of each phase in the natural coordinate system can be obtained after coordinate transformation to obtain the stator voltage and stator current of the axis. Further, input the stator voltage, stator current, electrical angular velocity corresponding to the target equation, and the fault correction coefficient corresponding to the target equation into the online resistance identification model. It should be noted that if the corresponding voltage equation is selected as the target equation to determine the online resistance identification model that satisfies the recursive least squares method, the nominal value of the fundamental magnetic flux linkage of the motor in the motor parameters needs to be combined.

[0030] Calculate the resistance matrix through a mathematical algorithm (such as the recursive least squares method). The resistance matrix contains the stator resistance corresponding to the target equation and the value of the high-resistance contact resistance of the faulty phase. The stator resistance can reflect the resistance characteristics of the multiphase permanent magnet synchronous motor during normal operation, and the high-resistance contact resistance can represent the increased resistance value of the faulty phase due to poor contact.

[0031] In this embodiment, the method responds to the high-resistance contact fault of the multiphase permanent magnet synchronous motor, determines the fault phase position, selects the corresponding compensation coefficient matrix according to the fault phase position, and calculates the fault correction coefficient matrix in combination with the stator current and the coordinate transformation matrix, and extracts the fault correction coefficient from the fault correction coefficient matrix. Further, obtain the expanded equations of the fault-state mathematical model considering the neutral point shift, select the appropriate voltage equation as the target equation, and construct an online resistance identification model that satisfies the recursive least squares method. Input the stator voltage, stator current, electrical angular velocity, and fault correction coefficient in the rotating coordinate system into the online resistance identification model to obtain a resistance matrix including the stator resistance and the high-resistance contact resistance of the fault phase. This method can identify the high-resistance contact resistance and the stator resistance in real time, improve the performance of the fault-tolerant control algorithm, and ensure the reliability and safety of the multiphase permanent magnet synchronous motor.

[0032] In one embodiment, as Figure 2 shown, obtaining the expanded equations of the fault-state mathematical model considering the neutral point shift of the multiphase permanent magnet synchronous motor in the rotating coordinate system includes the following steps: Step 201: Construct the initial fault-state model of the multiphase permanent magnet synchronous motor in the natural coordinate system; The initial fault-state model in the natural coordinate system can reflect the basic electromagnetic relationship of the multiphase permanent magnet synchronous motor in the fault state. The initial fault-state model in the natural coordinate system can be based on the basic voltage equation and flux linkage equation of the multiphase permanent magnet synchronous motor, considering motor parameters such as stator resistance, inductance, and the nominal value of the permanent magnet flux linkage. When constructing the initial fault-state model in the natural coordinate system, the influence of the high-resistance contact fault also needs to be considered, that is, a high-resistance contact resistance is introduced into the fault phase.

[0033] Exemplarily, taking a five-phase permanent magnet synchronous motor as an example, the expression for establishing the initial fault-state model of the five-phase permanent magnet synchronous motor in the natural coordinate system is as follows: ; where is the phase voltage matrix of the fault-state five-phase permanent magnet synchronous motor; is the phase current matrix of the fault-state five-phase permanent magnet synchronous motor; is the stator resistance matrix, where is the stator resistance, is the identity matrix; is the high-resistance contact resistance matrix when the fault phase is phase; is the stator flux linkage matrix, where is the stator inductance matrix, is the permanent magnet flux linkage matrix, represents the differential symbol.

[0034] Furthermore, the expressions for the phase voltage matrix , the phase current matrix , the high-resistance contact fault resistance matrix when the fault phase is phase , the stator flux linkage matrix , the stator inductance matrix and the permanent magnet flux linkage matrix are respectively: ; ; ; ; ; ; Among them, is the phase voltage of the five-phase permanent magnet synchronous motor in the fault state, that is, the voltage with respect to the neutral point; , , , , are the phase currents of the five-phase permanent magnet synchronous motor in the fault state; is the high-resistance contact resistance when the fault phase is phase, is the high-resistance contact resistance coefficient. When , then , , then ; 、 、 、 、 is the stator phase flux linkage; is the stator phase self-inductance; represents phase and phase mutual inductance; 、 、 、 、 represents the permanent magnet phase flux linkage.

[0035] Step 202: Determine the neutral point voltage matrix of the multiphase permanent magnet synchronous motor based on the offset of the neutral point of the multiphase permanent magnet synchronous motor. The neutral point voltage matrix is the neutral point-to-ground voltage matrix. When the multiphase permanent magnet synchronous motor operates normally, the voltage between the neutral point and the ground is zero. However, in the abnormal situation of a high-resistance contact fault, due to the increase in the resistance of the faulty phase, the current distribution changes, resulting in the offset of the neutral point potential, and the neutral point-to-ground voltage is no longer zero.

[0036] It should be noted that the neutral point voltage matrix is a matrix form used to represent the change of the neutral point-to-ground voltage. The neutral point voltage matrix can include the influence of each phase on the neutral point voltage. By analyzing the neutral point voltage matrix, the degree and direction of the neutral point offset can be understood, and then the operating state of the multiphase permanent magnet synchronous motor can be evaluated and fault diagnosed.

[0037] Exemplarily, taking a five-phase permanent magnet synchronous motor as an example, based on Kirchhoff's voltage law, the expressions between the terminal voltage, phase voltage, and neutral point-to-ground voltage are as follows: ; Among them, is the terminal voltage matrix of the five-phase permanent magnet synchronous motor in the fault state, is the neutral point-to-ground voltage matrix when the faulty phase is phase. Further, the expression of the voltage equation of the five-phase permanent magnet synchronous motor considering the neutral point voltage in the natural coordinate system is: = ; Among them, is the back electromotive force matrix, . The terminal voltage matrix , the back electromotive force matrix , and the neutral point-to-ground voltage matrix are expressed as: ; ; ; Among them, is the terminal voltage of the five-phase permanent magnet synchronous motor in the fault state, that is, the voltage to the ground; is the back electromotive force of the five-phase permanent magnet synchronous motor; is the phase neutral point-to-ground voltage when the faulty phase is phase.

[0038] It should be noted that the single-phase high-resistance contact fault of the five-phase permanent magnet synchronous motor, such as Figure 6As shown. In a healthy state, it can be considered that the neutral point N of the five-phase permanent magnet synchronous motor coincides with the grounding point O. The contact resistance of the high-resistance contact fault will cause the neutral point of the system to shift, resulting in the neutral point voltage . The five-phase permanent magnet synchronous motor adopts a five-phase star connection. Therefore, the sum of the five-phase currents is 0, that is . In addition, the phase windings of the five-phase permanent magnet synchronous motor are symmetric with each other. Therefore, the five-phase back electromotive forces are balanced, that is . According to Kirchhoff's law, the sum of the voltages in a closed loop is zero. Therefore . Sum the voltage equations of the five-phase permanent magnet synchronous motor in the fault state considering the neutral point voltage in the natural coordinate system, and perform algebraic combination on the terms with the same variables. The final combined expression obtained is as follows: ; ; Among them, is the self-inductance of the stator winding, ; is the mutual inductance of the stator winding, ; is the phase inductance of the stator winding, .

[0039] Furthermore, the expression of the neutral point voltage matrix of the five-phase permanent magnet synchronous motor under a single-phase high-resistance contact fault is: ; ; Step 203: Based on the neutral point voltage matrix and the initial model in the fault state, determine the expanded equations of the fault state model.

[0040] The neutral point voltage matrix describes the change of the neutral point voltage with respect to the ground, reflecting the degree of neutral point shift. The initial model in the fault state is a mathematical description of the basic electromagnetic relationship of the motor considering the influence of the high-resistance contact fault in the natural coordinate system, including motor parameters such as stator resistance, inductance, and nominal value of permanent magnet flux linkage, as well as the high-resistance contact resistance of the fault phase.

[0041] In the process of determining the expanded equations of the fault state model, the neutral point shift situation reflected by the neutral point voltage matrix can be incorporated into the initial model in the fault state, so as to obtain a set of equations that can comprehensively describe the operating characteristics of the motor in the fault state. The expanded equations of the fault state model can include the relationships between stator voltage, stator current, electrical angular velocity, motor parameters (at least one of stator resistance, nominal value of flux linkage, and inductance) in the motor rotating coordinate system, and the high-resistance contact resistance, and consider the influence of the fault on the motor performance.

[0042] In one embodiment, as Figure 3As shown, based on the neutral point voltage matrix and the initial fault state model, the expansion equations of the fault state mathematical model are determined, including the following steps: Step 301: Based on the neutral point voltage matrix and the initial fault state mathematical model, construct a transient fault state mathematical model of the multi-phase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system; The neutral point voltage matrix provides the variation of the neutral point voltage to the ground, reflecting the degree of neutral point offset. The initial fault state mathematical model describes the basic electromagnetic relationship of the motor in the fault state, including parameters such as stator resistance, inductance, permanent magnet flux linkage, etc., as well as the high resistance contact resistance of the fault phase. By combining the neutral point voltage matrix with the initial fault state model, a more comprehensive transient fault state mathematical model can be established.

[0043] The transient fault state mathematical model can more accurately describe the operating characteristics of the multi-phase permanent magnet synchronous motor in the fault state, including the variation of the voltage and current of each phase. In the natural coordinate system, the transient fault state mathematical model retains the original physical characteristics of the multi-phase permanent magnet synchronous motor and also considers the influence of the fault on the motor performance, enabling more accurate analysis and prediction of the motor behavior when the fault occurs.

[0044] Step 302: Based on the transient fault state mathematical model and the coordinate transformation matrix and , construct a fault state mathematical model of the multi-phase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system; To transform the transient fault state mathematical model to the rotating coordinate system, the coordinate transformation matrices and need to be applied. The transformation is usually used to transform the natural coordinate system of three-phase or more phases into a stationary coordinate system (such as the coordinate system), and the transformation can be used to transform the stationary coordinate system into a rotating coordinate system (such as the

[0045] coordinate system). Through coordinate transformation, variables such as voltage, current, and magnetic flux in the natural coordinate system can be transformed into the corresponding variables in the rotating coordinate system. The purpose of this is to simplify the analysis and control. In the rotating coordinate system, the equations of the motor can be decoupled, making the control strategy easier to implement. During the transformation process, it is necessary to ensure that the influence of the neutral point offset is correctly mapped to the rotating coordinate system. The fault state mathematical model in the rotating coordinate system will include the voltage equations corresponding to the

[0046] Step 303: Determine the expanded equations of the fault state mathematical model based on the fault state mathematical model.

[0047] The fault state mathematical model is a comprehensive mathematical description that covers the main electromagnetic relationships and dynamic behaviors of a multi-phase permanent magnet synchronous motor in a fault state. By expanding the voltage equations in the fault state mathematical model along different coordinate axes, a set of equations can be obtained. Each equation corresponds to a coordinate axis and clearly shows the relationship between the voltage on that axis and the motor parameters, high-resistance contact resistance, stator current, and electrical angular velocity.

[0048] In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, the vector control block diagram of the five-phase permanent magnet synchronous motor is as Figure 4 shown, adopting a double closed-loop control structure of a speed loop and a current loop. The outer speed loop uses PI control to generate the reference value of the fundamental quadrature axis current, and the reference value of the fundamental quadrature axis current is . Set the fundamental direct axis current , the third harmonic direct axis current , and the third harmonic quadrature axis current reference values are all 0. After performing Park inverse transformation and Clarke inverse transformation using the coordinate transformation matrices and , the reference values of the five-phase currents in the natural coordinate system are obtained. The reference values of the five-phase currents are respectively , , , , and , which are used as the inputs of the inner current loop. The inner current loop uses five parallel PR controllers, and its output is the reference values of the five-phase voltages. The reference values of the five-phase voltages are respectively , , , , and . Finally, through PWM modulation and a five-phase inverter, the stable operation of the motor is controlled. When a high-resistance contact fault occurs, the torque ripple can be effectively suppressed by the PR controller, and the consistency of each phase current with the normal operating condition can be maintained. When the contact resistance exceeds the critical threshold and causes a sudden change in current, it is equivalent to an open-circuit fault condition. Among them, represents the electrical angular velocity of the five-phase permanent magnet synchronous motor, and represents the electrical angle of the five-phase permanent magnet synchronous motor.

[0049] In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, the expression of the fault state transition mathematical model of the five-phase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system is: ; where is a matrix composed of a high-resistance contact resistance and an identity matrix, ; is the compensation coefficient matrix when the faulty phase is phase.

[0050] It should be noted that and The specific derivation process is as follows: ; ; .

[0051] Taking phase as an example, simplifying the above formula, we can get: ; ; Among them, , .

[0052] Similarly, we can derive .

[0053] ; ; In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, the expression of the mathematical model of the fault state considering the neutral point offset in the rotating coordinate system of the five-phase permanent magnet synchronous motor is: ; Among them, is the fault state voltage matrix in the rotating coordinate system; is the fault state current matrix in the rotating coordinate system; and are the coordinate transformation matrices; is the flux linkage matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux linkage matrix in the rotating coordinate system; is the electrical angular velocity matrix in the rotating coordinate system; is the fault correction coefficient matrix when the faulty phase is phase.

[0054] Exemplarily, a five-phase permanent magnet synchronous motor is taken as an example. In the natural coordinate system, the voltage equation of the five-phase permanent magnet synchronous motor has time-varying, non-linear and coupling characteristics. Conducting parameter identification in this coordinate system has problems such as large computational amount and parameter coupling. To achieve parameter identification, the present application adopts the vector space decoupling method to obtain the decoupling model in the rotating coordinate system. The coordinate transformation of the five-phase permanent magnet synchronous motor is as Figure 5 shown, where is the natural coordinate system of the five-phase permanent magnet synchronous motor; is the stationary coordinate system of the five-phase permanent magnet synchronous motor; is the rotating coordinate system of the five-phase synchronous motor, as shown in (a) of Figure 5 ; is the fundamental wave subspace, and the rotational speed is the fundamental wave electrical angular velocity . As shown in (b) of Figure 5 ; is the third harmonic subspace, and the rotational speed is 3 times the fundamental wave electrical angular velocity . From the natural coordinate system to the stationary coordinate system the transformation matrix is and the expression of is: where .

[0055] The variables in the stationary coordinate system are rotating variables. To further solve the problem of time-varying coupling of the variables of the rotating electrical machine, the transformation is used to convert the sine variables in the stationary coordinate system to the DC decoupled quantities in the rotating coordinate system . The matrix expression of this coordinate transformation is: ; where is the electrical angle.

[0056] Exemplarily, for the fault state transition mathematical model of the five-phase permanent magnet synchronous motor considering neutral point offset, the coordinate transformation process from the natural coordinate system to the rotating coordinate system is as follows:

[0057] where ; Furthermore, the voltage matrix in the rotating coordinate system, the current matrix in the rotating coordinate system, the resistance matrix in the rotating coordinate system, and the inductance matrix , the permanent magnet flux linkage matrix in the rotating coordinate system , the electrical angular velocity matrix in the rotating coordinate system and the fault coefficient matrix are expressed as follows: ; ; ; ; ; ; ; Among them, respectively represent the stator voltages on the axis in the rotating coordinate system, is the zero-sequence voltage; is the stator current on the axis in the rotating coordinate system, is the zero-sequence current; , are the permanent magnet flux linkages of the fundamental wave subspace and the third harmonic subspace respectively; is the inductance on the axis in the rotating coordinate system, is the stator leakage inductance; is the electrical angular velocity of the five-phase permanent magnet synchronous motor; is the electrical angle of the five-phase permanent magnet synchronous motor; is the fault correction coefficient matrix The element corresponding to the first column of the row represents the fault correction coefficient of the voltage equation corresponding to the phase of the five-phase permanent magnet synchronous motor when a high-resistance contact fault occurs on the axis.

[0058] In one embodiment, the expression of the expansion equation of the fault state mathematical model of the five-phase permanent magnet synchronous motor considering neutral point shift in the rotating coordinate system is: ; It should be noted that The voltage equation corresponding to the axis is an equation related to the stator voltage , the stator current , and , the electrical angular velocity , the motor parameters, the high-resistance contact resistance and the fault correction coefficient. Among them, The motor parameters corresponding to the axis include the inductance corresponding to the , Inductance corresponding to the axis and stator resistance .

[0059] The voltage equation corresponding to the axis is the stator voltage, stator current , and electrical angular velocity , motor parameters, high-resistance contact resistance , and fault correction factor associated equation. Among them, the motor parameters corresponding to the axis include the inductance corresponding to the , the inductance corresponding to the axis, stator resistance , and the nominal value of the fundamental subspace permanent magnet flux linkage .

[0060] The voltage equation corresponding to the axis is the stator voltage, stator current , and electrical angular velocity , motor parameters, high-resistance contact resistance , and fault correction factor associated equation. Among them, the motor parameters corresponding to the axis include the inductance corresponding to the , the inductance corresponding to the axis and stator resistance .

[0061] The voltage equation corresponding to the axis is the stator voltage, stator current , and electrical angular velocity , motor parameters, high-resistance contact resistance , and fault correction factor associated equation. Among them, among them, the motor parameters corresponding to the axis include the inductance corresponding to the , the inductance corresponding to the axis, stator resistance , and the nominal value of the fundamental subspace permanent magnet flux linkage .

[0062] Furthermore, as Figure 6As shown in the figure, taking a five-phase permanent magnet synchronous motor as an example, the five-phase permanent magnet synchronous motor adopts a double closed-loop vector control of a speed loop and a current loop. When the motor is in a healthy state, the state variables in the rotating coordinate system are all direct current quantities, and the state variables include current and voltage. Therefore, when the motor operates stably in the healthy state, the state variables remain unchanged, and only one motor parameter can be identified by one voltage equation. In the fault state, due to the access of a high-resistance contact resistance, the voltage of the faulty phase increases, and the voltages of the other phases decrease, resulting in the imbalance of the stator current and voltage. The voltage in the reconstructed rotating coordinate system shows a sinusoidal law transformation, and the current is still a direct current quantity, and the current differential term can be ignored. Therefore, in the expansion equation of the fault-state mathematical model of the five-phase permanent magnet synchronous motor considering the neutral point shift in the rotating coordinate system, two motor parameters can be identified by each voltage equation at one time. Considering that the five-phase permanent magnet synchronous motor is generally a surface-mounted motor, this type of motor often adopts control. Without considering the third harmonic back electromotive force, . Further, the expansion equation of the fault-state mathematical model of the five-phase permanent magnet synchronous motor considering the neutral point shift in the rotating coordinate system can be simplified as: ; In one embodiment, select the voltage equation corresponding to the axis in the rotating coordinate system of the expansion equation set of the fault-state mathematical model as the target equation; obtain the stator voltage, stator current, and electrical angular velocity in the rotating coordinate system corresponding to the target equation, and input the stator voltage, stator current, electrical angular velocity, and fault correction coefficient into the online resistance identification model, and the resistance matrix obtained is: Obtain the axis corresponding stator voltage , stator current and electrical angular velocity , input the stator voltage , stator current , electrical angular velocity and fault correction coefficient into the online resistance identification model, and the resistance matrix is obtained; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

[0063] Input the stator voltage , stator current , electrical angular velocity and fault correction coefficient into the online resistance identification model. The fault correction coefficient is extracted according to the position of the faulty phase and the fault correction coefficient matrix , and is used to adjust the faulty phase in the The voltage equation on the axis is used to compensate for the impact of faults on the motor performance. The online resistance identification model utilizes these input data and calculates the resistance matrix through the recursive least squares method. The resistance matrix contains the estimated values of the stator resistance and the high-resistance contact resistance of the faulty phase. The stator resistance reflects the resistance characteristics of the motor during normal operation, while the high-resistance contact resistance represents the increased resistance value of the faulty phase due to poor contact.

[0064] In one embodiment, the expression of the online resistance identification model includes the input matrix of the online resistance identification model, the coefficient matrix of the online resistance identification model, and the output of the online resistance identification model; Among them, the expression of the online resistance identification model is: , represents the output of the online resistance identification model, represents the input matrix of the online resistance identification model, represents the coefficient matrix of the online resistance identification model, and the coefficient matrix of the online resistance identification model is equal to the resistance matrix; among them, , , .

[0065] Among them is the stator voltage of the axis, is the stator current of the axis, is the fault correction coefficient corresponding to the axis, is the electrical angular velocity of the motor, is the nominal value of the fundamental permanent magnet flux linkage. The input matrix contains two key variables affecting the output: the stator current and the fault correction coefficient , which are presented in the form of a row vector. The coefficient matrix is composed of the stator resistance and the high-resistance contact resistance of the faulty phase. These two parameters are the core unknowns of the model and need to be determined through the identification model.

[0066] The output of the online resistance identification model is actually the form obtained by transforming and arranging the voltage equation of the motor. The elements of the input matrix and correspond to the stator current and the fault correction coefficient in the equation respectively, and the elements of the coefficient matrix and correspond to the stator resistance and the high-resistance contact resistance of the faulty phase. Through the online resistance identification model, combined with the nominal value of the fundamental flux linkage After the phase voltage and phase current measured in real time are subjected to coordinate transformation, the obtained and the differential of the electrical angle measured by the position sensor in real time , calculate the resistance matrix , and then obtain the stator resistance and the high-resistance contact resistance of the faulty phase specific values.

[0067] In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, assuming that the five-phase permanent magnet synchronous motor phase has a high-resistance contact fault as an example, based on Figure 4 vector control block diagram of the five-phase permanent magnet synchronous motor, build in Matlab / Simulink including: speed loop PI controller, current loop PR controller, PWM modulation, five-phase inverter and motor mathematical model and other modules to achieve stable operation of the motor. The motor parameters and other simulation parameters used in the simulation are shown in the following table:

[0068] Set the simulation speed to , phase has a high-resistance contact fault. When a high-resistance contact fault occurs, the current loop uses the above-mentioned PR controller. At this time, the five-phase current is the same as the current under the healthy condition. However, due to the access of the fault resistance, considering the offset of the five-phase neutral point voltage, the five-phase phase voltage under the fault state is not equal to the five-phase terminal voltage. Using the online resistance identification method for high-resistance contact faults of multi-phase permanent magnet synchronous motors proposed in this application, the parameter identification simulation results of the high-resistance contact resistance and the stator winding resistance are as Figure 7 shown. Figure 7 In (a) of , the ordinate is the value of the high-resistance contact resistance, and the abscissa is time; Figure 7 In (b) of , the ordinate is the value of the stator resistance, and the abscissa is time. Figure 7 In (a) of is the identification simulation result of the high-resistance contact resistance. At 0.1 s, the high-resistance contact resistance suddenly changes to the high-resistance contact resistance , and at 0.5 s, the high-resistance contact resistance suddenly changes to . The simulation identification error is 2.5% in both cases, and it can respond quickly when the high-resistance contact resistance changes, with good dynamic performance and accuracy. Figure 7 In (b) of is the identification result of the stator resistance, and the identification error is less than 2.3%, achieving accurate identification of the stator resistance and the fault contact resistance does not affect the identification accuracy of the stator resistance.

[0069] Based on the same concept, an on-line resistance identification system for high-resistance contact faults of a multi-phase permanent magnet synchronous motor is further provided in an embodiment of the present application. The system includes a multi-phase permanent magnet synchronous motor and a controller, and the controller can execute the above-mentioned on-line resistance identification method for high-resistance contact faults of a multi-phase permanent magnet synchronous motor.

[0070] The controller can construct a fault-state transition mathematical model based on the neutral-point voltage matrix and the initial fault-state model, and then convert it into a fault-state mathematical model in the rotating coordinate system through a coordinate transformation matrix. Further, one of the voltage equations corresponding to an axis is selected from the expanded equations of the model as the target equation, and the corresponding stator voltage, stator current, electrical angular velocity, and fault correction coefficient are input into the on-line resistance identification model to calculate a resistance matrix including the stator resistance and the high-resistance contact resistance of the fault phase.

[0071] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0072] The above embodiments only represent several implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor, characterized in that, The method includes: In response to a high-resistance contact fault of the multiphase permanent magnet synchronous motor, determining the position of the faulty phase where the high-resistance contact fault occurs; the position of the faulty phase is any phase of the multiphase permanent magnet synchronous motor; Select the corresponding compensation coefficient matrix according to the faulty phase position , the compensation coefficient matrix is for the multi-phase permanent magnet synchronous motor when a high-resistance contact fault occurs in the phase; According to the compensation coefficient matrix combine the stator current and the coordinate transformation matrix to calculate the corresponding fault correction coefficient matrix , extract the fault correction coefficient from the fault correction coefficient matrix ; the fault correction coefficient is the element corresponding to the first column of the th row of the fault correction coefficient matrix th, representing the fault correction coefficient of the voltage equation corresponding to the axis when a high-resistance contact fault occurs in the phase of the multiphase permanent magnet synchronous motor ; Obtain the expanded equations of the fault-state mathematical model of the poly-phase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system; the expanded equations of the fault-state mathematical model include the voltage equation corresponding to the axis; the voltage equation is an equation related to the stator voltage, stator current, electrical angular velocity, motor parameters, and high-resistance contact resistance in the rotating coordinate system Selecting at least one voltage equation in the expanded equations of the faulty-state mathematical model as the target equation, and determining an online resistance identification model that satisfies the recursive least squares method based on the target equation; Obtain the stator voltage, stator current, and electrical angular velocity of the axis corresponding to the target equation, and input the stator voltage, the stator current, the electrical angular velocity, and the fault correction coefficient into the online resistance identification model to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

2. The online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 1, characterized in that Obtaining the expanded equations of the faulty-state mathematical model of the multiphase permanent magnet synchronous motor considering neutral point offset in the rotating coordinate system, including: Constructing an initial faulty-state model of the multiphase permanent magnet synchronous motor in the natural coordinate system; Based on the offset of the neutral point of the multiphase permanent magnet synchronous motor, determining the neutral point voltage matrix of the multiphase permanent magnet synchronous motor, and the neutral point voltage matrix is the neutral point-to-ground voltage matrix; Based on the neutral point voltage matrix and the initial faulty-state model, determining the expanded equations of the faulty-state model.

3. The on-line resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 2, characterized in that, Based on the neutral point voltage matrix and the initial faulty-state model, determining the expanded equations of the faulty-state mathematical model, including: Based on the neutral point voltage matrix and the initial faulty-state mathematical model, constructing a transitional faulty-state mathematical model of the multiphase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system; Based on the above fault state transition mathematical model and the coordinate transformation matrix and , a fault state mathematical model of the multi-phase permanent magnet synchronous motor considering neutral point shift in the rotating coordinate system is constructed; Based on the faulty-state mathematical model, determining the expanded equations of the faulty-state mathematical model.

4. The online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 2, wherein The expression of the neutral point voltage matrix of the multiphase permanent magnet synchronous motor is: ； Among them, is the number of phases of the polyphase permanent magnet synchronous motor, is the neutral point voltage matrix to ground when the faulty phase is phase, is the faulty phase current when the faulty phase is phase, is the high resistance contact resistance when the faulty phase is phase.

5. The online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 3, wherein The expression of the transitional faulty-state mathematical model of the multiphase permanent magnet synchronous motor considering neutral point offset in the natural coordinate system is: ； Among them, represents the terminal voltage matrix of the faulty multi-phase permanent magnet synchronous motor; represents the phase current matrix of the faulty multi-phase permanent magnet synchronous motor; is the stator resistance matrix, , is the stator resistance, is the identity matrix; is a matrix composed of the high-resistance contact resistance and the identity matrix, ; is the compensation coefficient matrix when the faulty phase is phase; is the stator flux linkage matrix, , is the stator inductance matrix, is the permanent magnet flux linkage matrix, represents the differential symbol.

6. The online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 3, wherein The expression of the faulty-state mathematical model is: ； ； Among them, is the fault-state voltage matrix in the rotating coordinate system; is the fault-state current matrix in the rotating coordinate system; and are the coordinate transformation matrices; is the flux linkage matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux linkage matrix in the rotating coordinate system; is the electrical angular velocity matrix in the rotating coordinate system; is the fault correction coefficient matrix when the fault phase is phase, is the fault correction coefficient matrix the element corresponding to the first column of the row, indicating the axis fault correction coefficient of the voltage equation when a high-resistance contact fault occurs in the phase of the multi-phase permanent magnet synchronous motor.

7. The on-line resistance identification method for high-resistance contact faults of a multi-phase permanent magnet synchronous motor according to claim 1, characterized in that The expression of the expanded equation of the faulty-state mathematical model is: Among them, represents the electrical angular velocity of the poly-phase permanent magnet synchronous motor, respectively represent the stator voltages on the axis in the rotating coordinate system, is the stator current on the axis in the rotating coordinate system, , , … are k the permanent magnet flux linkages of the nth harmonic subspace, is the inductance on the axis in the rotating coordinate system.

8. The online resistance identification method for high-resistance contact faults of a multiphase permanent magnet synchronous motor according to claim 1, wherein Select the voltage equation corresponding to the axis in the rotating coordinate system in the expanded equation set of the selected fault state mathematical model as the target equation; Obtain the stator voltage, stator current, and electrical angular velocity corresponding to the target equation, and input the stator voltage, the stator current, the electrical angular velocity, and the fault correction coefficient into the online resistance identification model to obtain a resistance matrix as follows: Obtain the stator voltage corresponding to the shaft , the stator current and the electrical angular velocity , and input the stator voltage , the electronic current , the electrical angular velocity and the fault correction coefficient into the online resistance identification model to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the faulty phase.

9. The on-line resistance identification method for high-resistance contact faults of a multi-phase permanent magnet synchronous motor according to claim 8, characterized in that The expression of the online resistance identification model includes the input matrix of the online resistance identification model, the coefficient matrix of the online resistance identification model, and the output of the online resistance identification model; Among them, the expression of the online resistance identification model is: , represents the output of the online resistance identification model, represents the input matrix of the online resistance identification model, represents the coefficient matrix of the online resistance identification model, and the coefficient matrix of the online resistance identification model is equal to the resistance matrix; among them, , , .

10. An on-line resistance identification system for high-resistance contact faults of a multiphase permanent magnet synchronous motor, characterized in that, The system includes a multiphase permanent magnet synchronous motor and a controller, and the controller can execute the online resistance identification method for high-resistance contact faults of the multiphase permanent magnet synchronous motor according to any one of claims 1 to 9.

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