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

Abstract

The present application provides an online resistance identification method for a high-resistance contact fault in a multi-phase permanent magnet synchronous motor, and relates to the technical field of multi-phase motor fault-tolerant control. The method comprises: determining the position of the fault phase where the high-resistance contact fault occurs, selecting a corresponding compensation coefficient matrix, calculating a corresponding fault correction coefficient matrix based on the compensation coefficient matrix in combination with the stator current and the coordinate transformation matrix, and extracting the fault correction coefficient; obtaining an expanded equation group of a fault state mathematical model taking into account the neutral point offset in a rotating coordinate system, selecting at least one voltage equation in the expanded equation group as a target equation, and determining an online resistance identification model that satisfies the recursive least squares method based on the target equation; inputting the stator voltage and stator current, electrical angular velocity, and fault correction coefficient in the rotating coordinate system corresponding to the target equation into the online resistance identification model to obtain a resistance matrix. The method can identify high-resistance contact resistance and stator resistance in real time, thereby improving the performance of the fault-tolerant control algorithm.

Description

Technical Field

[0001] The present application relates to the technical field of multi-phase motor fault-tolerant control, and in particular to an online resistance identification method for high-resistance contact faults of multi-phase permanent magnet synchronous motors. Background Art

[0002] Multiphase permanent magnet synchronous motors (PMSMs) are widely used in various fields due to their high power density, low torque ripple, and strong fault tolerance. However, they are susceptible to high-resistance contact failures. These failures, caused by manufacturing defects, thermal stress, vibration, or contact surface oxidation, can lead to stator current and voltage imbalances, increased local temperature rise, reduced average torque, and increased losses and heat. These failures can severely degrade the motor's operating performance and even damage the motor's drive system.

[0003] Fault-tolerant control algorithms in related technologies rely on fixed contact resistance parameters. However, the contact resistance is affected by temperature, oxidative corrosion, and mechanical stress, exhibiting dynamic, time-varying characteristics that limit the performance and accuracy of the control algorithm. Online parameter identification methods, such as those based on voltage equations, are unable to adapt to voltage and current imbalances under fault conditions, or those that rely on high-frequency signal injection, leading to 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 fault of a multi-phase permanent magnet synchronous motor to address the above technical problems. This method can identify high-resistance contact resistance and stator resistance in real time and improve the performance of the fault-tolerant control algorithm.

[0005] In a first aspect, the present application provides an online resistance identification method for a high-resistance contact fault of a multi-phase permanent magnet synchronous motor, the method comprising:

[0006] In response to a high-resistance contact fault of the multi-phase permanent magnet synchronous motor, determining a fault phase position where the high-resistance contact fault occurs; the fault phase position is any phase of the multi-phase permanent magnet synchronous motor;

[0007] According to the fault phase position, select the corresponding compensation coefficient matrix , compensation coefficient matrix Multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase matrix;

[0008] According to the compensation coefficient matrix Combine the stator current and coordinate transformation matrix to calculate the corresponding fault correction coefficient matrix , from the fault correction coefficient matrix Extract the fault correction factor from ;Fault correction factor is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents a multi-phase permanent magnet synchronous motor When a high-resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis;

[0009] Obtain the expanded equation group of the fault state mathematical model of the multi-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system; the expanded equation group of the fault state mathematical model includes The voltage equation corresponding to the axis; the voltage equation is the rotating coordinate system Equations related to the stator voltage, stator current, electrical angular velocity, motor parameters, and high-resistance contact resistance corresponding to the axis;

[0010] Selecting at least one voltage equation in the expanded equation group of the fault state mathematical model as a target equation, and determining an online resistance identification model that satisfies a recursive least squares method based on the target equation;

[0011] Get the target equation corresponding to The stator voltage, stator current and electrical angular velocity of the shaft, the stator voltage, stator current, electrical angular velocity and fault correction factor Input 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 fault phase.

[0012] In one embodiment, obtaining a set of expanded equations of a fault state mathematical model of a multi-phase permanent magnet synchronous motor taking into account a neutral point offset in a rotating coordinate system includes:

[0013] Construct the initial fault state model of the multi-phase permanent magnet synchronous motor in the natural coordinate system;

[0014] Based on the offset of the neutral point of the multi-phase permanent magnet synchronous motor, a neutral point voltage matrix of the multi-phase permanent magnet synchronous motor is determined, where the neutral point voltage matrix is a neutral point-to-ground voltage matrix;

[0015] Based on the neutral point voltage matrix and the initial fault state model, the fault state model expansion equation group is determined.

[0016] In one embodiment, based on the neutral point voltage matrix and the initial fault state model, a fault state mathematical model expansion equation group is determined, including:

[0017] Based on the neutral point voltage matrix and the initial mathematical model of the fault state, a fault state transition mathematical model of the multi-phase permanent magnet synchronous motor considering the neutral point offset is constructed in the natural coordinate system.

[0018] Based on the fault state transition mathematical model and coordinate transformation matrix 、 , construct a fault state mathematical model of a multi-phase permanent magnet synchronous motor considering neutral point offset in a rotating coordinate system;

[0019] The fault state mathematical model expansion equation group is determined based on the fault state mathematical model.

[0020] The mathematical model of the fault state transition of a multi-phase permanent magnet synchronous motor considering the neutral point offset in the natural coordinate system is expressed as follows:

[0021] ;

[0022] in, is the number of phases of the multiphase permanent magnet synchronous motor, The fault phase is The neutral point to ground voltage matrix of the phase, The fault phase is The fault phase current when the phase The fault phase is High-resistance contact resistance during phase transition.

[0023] The mathematical model of the fault state transition of a multi-phase permanent magnet synchronous motor considering the neutral point offset in the natural coordinate system is expressed as follows:

[0024] ;

[0025] in, Represents the terminal voltage matrix of the multi-phase permanent magnet synchronous motor in fault state; Represents the phase current matrix of the multi-phase permanent magnet synchronous motor in a fault state; is the stator resistance matrix, , is the stator resistance, for Identity matrix; is a matrix composed of high-resistance contact resistance and unit matrix, ; The fault phase is Phase compensation coefficient matrix; is the stator flux matrix, , is the stator inductance matrix, is the permanent magnet flux matrix, Represents the differential symbol.

[0026] In one embodiment, the mathematical model of the fault state is expressed as:

[0027] ;

[0028] ;

[0029] in, is the fault state voltage matrix in the rotating coordinate system; is the fault current matrix in the rotating coordinate system; and is the coordinate transformation matrix; is the magnetic flux matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux matrix in the rotating coordinate system; is the electric angular velocity matrix in the rotating coordinate system; The fault phase is The fault correction coefficient matrix when the phase is, is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents a multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis.

[0030] In one embodiment, the expanded equation of the fault state mathematical model is expressed as:

[0031] ;

[0032] in, represents the electrical angular velocity of the multi-phase permanent magnet synchronous motor, Respectively represent the rotating coordinate system The stator voltage of the shaft, In the rotating coordinate system The stator current of the shaft, 、 , … for k The permanent magnet flux linkage in the subharmonic subspace, In the rotating coordinate system The inductance of the shaft.

[0033] In one embodiment, the fault state mathematical model is selected to expand the equation group under the rotating coordinate system. The voltage equation corresponding to the axis is used as the target equation;

[0034] Obtain the stator voltage, stator current, electrical angular velocity and fault correction coefficient corresponding to the target equation Input the online resistance identification model and get the resistance matrix:

[0035] Get Stator voltage corresponding to the axis , stator current and electrical angular velocity , the stator voltage , electron current , electrical angular velocity and fault correction factor Input 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 fault phase.

[0036] In one embodiment, the expression of the online resistance identification model includes an input matrix of the online resistance identification model, a coefficient matrix of the online resistance identification model, and an output of the online resistance identification model;

[0037] 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, which is equal to the resistance matrix; , , .

[0038] In the second aspect, the present application also provides an online resistance identification system for high-resistance contact faults of a multi-phase permanent magnet synchronous motor, the system comprising a multi-phase permanent magnet synchronous motor and a controller, the controller being capable of executing the online resistance identification method for high-resistance contact faults of a multi-phase permanent magnet synchronous motor of the first aspect.

[0039] The above-mentioned online identification method for high-resistance contact faults in multiphase permanent magnet synchronous motors responds to a high-resistance contact fault in the motor by determining the fault phase location, selecting a corresponding compensation coefficient matrix based on the fault phase location, and calculating a fault correction coefficient matrix based on the stator current and coordinate transformation matrix. The fault correction coefficient is then extracted from the fault correction coefficient matrix. Furthermore, a mathematical model of the fault state is expanded to account for neutral point offset, and an appropriate voltage equation is selected as the target equation to construct an online resistance identification model that satisfies the recursive least squares method. The stator voltage, stator current, electrical angular velocity, and fault correction coefficient in the rotating coordinate system are input into the online resistance identification model to obtain a resistance matrix containing the stator resistance and the high-resistance contact resistance of the fault phase. This method can identify the high-resistance contact resistance and stator resistance in real time, improving the performance of the fault-tolerant control algorithm and ensuring the reliability and safety of the multiphase permanent magnet synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Flowchart of an online resistance identification method for high-resistance contacts of a multi-phase permanent magnet synchronous motor according to one embodiment;

[0041] Figure 2A flowchart of an embodiment for obtaining a set of equations for a fault state mathematical model of a multi-phase permanent magnet synchronous motor taking into account a neutral point offset in a rotating coordinate system;

[0042] Figure 3 A flowchart of an embodiment of determining a fault state mathematical model expansion equation group based on a neutral point voltage matrix and an initial fault state model;

[0043] Figure 4 is a vector control block diagram of a five-phase permanent magnet synchronous motor in one embodiment;

[0044] Figure 5 Schematic diagram of coordinate transformation of a five-phase permanent magnet synchronous motor in one embodiment;

[0045] Figure 6 Schematic diagram of a single-phase high-resistance contact fault of a five-phase permanent magnet synchronous motor in one embodiment;

[0046] Figure 7 In one embodiment, Simulation results of high-resistance contact resistance and stator resistance identification when a high-resistance contact fault occurs in one phase. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] In one embodiment, Figure 1 As shown, a method for online resistance identification of high-resistance contacts of a multi-phase permanent magnet synchronous motor is provided, the method comprising the following steps:

[0049] Step 101: In response to a high-resistance contact fault of a multi-phase synchronous motor, determining a fault phase position where the high-resistance contact occurs; the fault phase position is any phase of the multi-phase permanent magnet synchronous motor;

[0050] For example, a five-phase permanent magnet synchronous motor is used as an example. The five-phase synchronous motor has five phases (e.g. Five phases), these phases are symmetrically distributed in the five-phase synchronous motor and jointly drive the operation of the five-phase synchronous motor. It should be noted that in order to explain the technical solution more clearly in the following, the subsequent specific implementation methods are appropriately described using the permanent magnet five-phase synchronous motor as an example, that is, the following embodiments appear All specifically , such as the compensation coefficient matrix for , fault correction coefficient matrix for and yes The specific corresponding unit matrix yes Unit matrix, etc. It should be further explained that the following specific implementation will rotate the coordinate system The axis is simplified to axis.

[0051] It should be noted that a high-resistance contact fault refers to a significant increase in the contact resistance between the winding of a phase of a multiphase synchronous motor and the neutral point or ground of the multiphase permanent magnet synchronous motor. This can be caused by manufacturing defects, thermal stress, vibration, or oxidation of the contact surface. The phase experiencing a high-resistance contact fault typically exhibits increased voltage and decreased current, causing the neutral point voltage of the multiphase permanent magnet synchronous motor to shift, thereby affecting the performance of the entire multiphase permanent magnet synchronous motor.

[0052] Step 102: Select the corresponding compensation coefficient matrix according to the fault phase position , compensation coefficient matrix Multi-phase permanent magnet synchronous motor When a high-resistance contact fault occurs in the phase matrix;

[0053] When a phase is detected ( When a high resistance contact fault occurs in the phase ( Phase) position corresponding compensation coefficient matrix Among them, the compensation coefficient matrix is a The matrix is used to characterize the multi-phase permanent magnet synchronous motor The impact of a high-resistance contact fault on the overall performance of a multi-phase permanent magnet synchronous motor. The compensation coefficient matrix can compensate for the performance changes caused by the faulty phase by adjusting the voltage and current distribution of each phase.

[0054] It should be noted that the compensation coefficient matrix The parameters are predetermined based on the design characteristics and fault modes of the multi-phase permanent magnet synchronous motor. Once the fault phase position is determined, the corresponding compensation coefficient matrix is called , in order to achieve real-time adjustment of the voltage equation of the multi-phase permanent magnet synchronous motor.

[0055] Step 103: According to the compensation coefficient matrix Combine the stator current and coordinate transformation matrix to calculate the corresponding fault correction coefficient matrix , the fault correction coefficient matrix is a The matrix, from the fault correction coefficient matrix Extract the fault correction factor from ; is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents a multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis.

[0056] If a phase ( Phase) has a high resistance contact fault, based on the compensation coefficient matrix corresponding to the fault , combined with the stator current and coordinate transformation matrix to calculate the fault correction coefficient matrix corresponding to the fault From the fault correction coefficient matrix Extract the fault correction factor from , fault correction factor is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents a multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis. Fault correction factor It can be used to adjust the voltage equation of the fault phase on different coordinate axes in the rotating coordinate system to reflect the impact of the fault on the performance of the multi-phase permanent magnet synchronous motor.

[0057] For example, taking a five-phase permanent magnet synchronous motor as an example, in a five-phase permanent magnet synchronous motor, if If a high resistance contact fault occurs in the phase, The corresponding compensation coefficient matrix will be selected. The corresponding compensation coefficient matrix Combining the current stator current and the coordinate transformation matrix, we can calculate The corresponding fault correction coefficient matrix From the fault correction coefficient matrix Extract the fault correction factor from , fault correction factor is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents a multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis.

[0058] Step 104: Obtain a set of expanded equations for the fault state mathematical model of the multi-phase permanent magnet synchronous motor in a rotating coordinate system taking into account the neutral point offset; the set of expanded equations for the fault state mathematical model includes The voltage equation corresponding to the axis; the voltage equation is the rotating coordinate system Equations relating the stator voltage, stator current, electrical angular velocity, motor parameters, and high-resistance contact resistance corresponding to the axis;

[0059] Obtaining the expanded equations of the fault state mathematical model considering the neutral point offset in the rotating coordinate system involves converting the fault state mathematical model in the natural coordinate system of the motor to the fault state mathematical model in the rotating coordinate system and considering the influence of the neutral point offset. The expanded equations of the fault state mathematical model specifically include the corresponding The voltage equation for each axis describes how the stator voltage on the corresponding axis is affected by the combined effects of high-resistance contact resistance, motor parameters, electrical angular velocity, and stator current. The motor parameters are at least one of stator resistance, nominal flux linkage, and inductance.

[0060] Step 105: selecting at least one voltage equation in the expanded equation group of the fault state mathematical model as a target equation, and determining an online resistance identification model that satisfies the recursive least squares method based on the target equation;

[0061] For example, you can choose The voltage equation corresponding to the axis is used as the target equation. After the voltage equation of the axis is the target equation, we can The voltage equation of the shaft is transformed algebraically so that it can be expressed as a linear relationship between the output variable of the fault state mathematical model and the input variable and the parameters to be identified.

[0062] It should be noted that during online resistance identification, a model that satisfies the recursive least squares method is selected to achieve optimal parameter estimation. The core principle of the recursive least squares method is to solve for unknown parameters by minimizing the sum of squared residuals between observed values and model predictions. In online resistance identification, the recursive least squares method effectively handles multivariable linear regression problems, providing unbiased estimates with low computational complexity and ease of real-time application. This enables accurate resistance parameter estimation for multiphase permanent magnet synchronous motors after a fault occurs.

[0063] Step 106: Obtain the target equation corresponding to The stator voltage, stator current and electrical angular velocity of the shaft, the stator voltage, stator current, electrical angular velocity and fault correction factor The online resistance identification model is input to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the fault phase.

[0064] Obtain the stator voltage, stator current and electrical angular velocity corresponding to the target equation. The sensors of the multi-phase permanent magnet synchronous motor can measure the corresponding voltage and current in the natural coordinate system in real time. The voltage and current of each phase in the natural coordinate system can be obtained after coordinate transformation. Furthermore, the stator voltage, stator current, electrical angular velocity corresponding to the target equation and the fault correction coefficient corresponding to the target equation are converted into Input into the online resistance identification model. It should be noted that if you select When the corresponding voltage equation is used as the target equation to determine the online resistance identification model that satisfies the recursive least squares method, it is necessary to combine the nominal value of the motor fundamental flux in the motor parameters.

[0065] A resistance matrix is calculated using a mathematical algorithm (such as the recursive least squares method). This matrix contains the stator resistance corresponding to the target equation and the high-resistance contact resistance of the faulty phase. The stator resistance reflects the resistance characteristics of a multiphase permanent magnet synchronous motor during normal operation, while the high-resistance contact resistance indicates the increased resistance of the faulty phase due to poor contact.

[0066] In this embodiment, in response to a high-resistance contact fault in a multiphase permanent magnet synchronous motor, the method determines the fault phase location, selects a corresponding compensation coefficient matrix based on the fault phase location, and calculates a fault correction coefficient matrix based on the stator current and coordinate transformation matrix. The fault correction coefficient is then extracted from the fault correction coefficient matrix. Furthermore, a system of equations is expanded to determine the mathematical model of the fault state, taking into account neutral point offset. An appropriate voltage equation is selected as the target equation, and an online resistance identification model that satisfies the recursive least squares method is constructed. The stator voltage, stator current, electrical angular velocity, and fault correction coefficient in the rotating coordinate system are input into the online resistance identification model to obtain a resistance matrix containing the stator resistance and the high-resistance contact resistance of the fault phase. This method can identify the high-resistance contact resistance and stator resistance in real time, improving the performance of the fault-tolerant control algorithm and ensuring the reliability and safety of the multiphase permanent magnet synchronous motor.

[0067] In one embodiment, Figure 2 As shown, obtaining a set of equations for a fault state mathematical model of a multi-phase permanent magnet synchronous motor considering neutral point offset in a rotating coordinate system includes the following steps:

[0068] Step 201: constructing an initial fault state model of a multi-phase permanent magnet synchronous motor in a natural coordinate system;

[0069] The initial fault state model in the natural coordinate system can reflect the fundamental electromagnetic relationships in a multiphase permanent magnet synchronous motor under fault conditions. This model is based on the basic voltage and flux equations for a multiphase permanent magnet synchronous motor and considers motor parameters such as stator resistance, inductance, and the nominal value of the permanent magnet flux. When constructing this initial fault state model in the natural coordinate system, the impact of high-resistance contact faults must also be considered, i.e., high-resistance contact resistance is introduced in the faulty phase.

[0070] For example, 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:

[0071] ;

[0072] in, is the phase voltage matrix of the five-phase permanent magnet synchronous motor in fault state; is the phase current matrix of the five-phase permanent magnet synchronous motor in fault state; is the stator resistance matrix, , is the stator resistance, for Identity matrix; The fault phase is High-resistance contact resistance matrix during phase; is the stator flux matrix, , is the stator inductance matrix, is the permanent magnet flux matrix, Represents the differential symbol.

[0073] Furthermore, the phase voltage matrix , phase current matrix , fault phase is High-resistance contact fault resistance matrix at phase , stator flux matrix , stator inductance matrix and permanent magnet flux matrix The expressions are:

[0074] ;

[0075] ;

[0076] ;

[0077] ;

[0078] ;

[0079] ;

[0080] in, is the phase voltage of the five-phase permanent magnet synchronous motor in the fault state, that is, the neutral point voltage; 、 、 、 、 is the phase current of the five-phase permanent magnet synchronous motor in the fault state; The fault phase is High-resistance contact resistance during phase is the high-resistance contact resistance coefficient, when ,but , ,but ; 、 、 、 、 is the stator phase flux linkage; It is the stator phase self-sensor; express phase and mutual inductance between phases; 、 、 、 、 Represents the permanent magnet phase flux.

[0081] Step 202: determining a neutral point voltage matrix of the multi-phase permanent magnet synchronous motor based on the offset of the neutral point of the multi-phase permanent magnet synchronous motor, where the neutral point voltage matrix is a neutral point-to-ground voltage matrix;

[0082] When a multi-phase permanent magnet synchronous motor is operating normally, the voltage between the neutral point and the ground is zero. However, in the abnormal case of a high-resistance contact fault, the resistance of the faulty phase increases, the current distribution changes, and the neutral point potential shifts, so the neutral point voltage to the ground is no longer zero.

[0083] It's important to note that the neutral-point voltage matrix represents the voltage variation between the neutral point and ground. This matrix includes the impact of each phase on the neutral-point voltage. By analyzing the neutral-point voltage matrix, we can understand the extent and direction of neutral-point offset, enabling us to assess the operating status and conduct fault diagnosis for multiphase permanent magnet synchronous motors.

[0084] For example, 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:

[0085] ;

[0086] in, is the terminal voltage matrix of the five-phase permanent magnet synchronous motor in fault state, The fault phase is Furthermore, the voltage equation of the five-phase permanent magnet synchronous motor in the natural coordinate system considering the neutral point voltage in the fault state is expressed as follows:

[0087] = ;

[0088] in, is the opposite potential matrix, Terminal voltage matrix , back EMF matrix , neutral point to ground voltage matrix The expression is:

[0089] ;

[0090] ;

[0091] ;

[0092] in, is the terminal voltage of the five-phase permanent magnet synchronous motor in the fault state, that is, the voltage to ground; is the opposite electromotive force of the five-phase permanent magnet synchronous motor; The fault phase is The phase neutral point to ground voltage at phase.

[0093] It should be noted that the single-phase high-resistance contact fault of the five-phase permanent magnet synchronous motor is as follows: Figure 6 As shown. In a healthy state, the neutral point N of the five-phase permanent magnet synchronous motor can be considered to be the same as the ground point O. The contact resistance of a high-resistance contact fault will cause the neutral point of the system to shift, resulting in a center point voltage The five-phase permanent magnet synchronous motor adopts a five-phase star connection, so the sum of the five-phase current is 0, that is In addition, the phase windings of the five-phase permanent magnet synchronous motor are symmetrical to each other, so the five phases have a balanced electromotive force, that is, According to Kirchhoff's law, the sum of the closed circuit voltages is zero, so 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 are summed and the terms with the same variables are algebraically combined. The final combined expression is as follows:

[0094] ;

[0095] ;

[0096] in, is the self-inductance of the stator winding, ; is the mutual inductance of the stator winding, ; is the stator winding phase inductance, .

[0097] Furthermore, the neutral point voltage matrix of the five-phase permanent magnet synchronous motor under a single-phase high-resistance contact fault is expressed as:

[0098] ;

[0099] ;

[0100] Step 203: Determine a fault state model expansion equation group based on the neutral point voltage matrix and the initial fault state model.

[0101] The neutral-point voltage matrix describes the change in the neutral-point voltage to ground, reflecting the degree of neutral-point offset. The initial fault state model is a mathematical description of the basic electromagnetic relationships of the motor in the natural coordinate system, considering the influence of high-resistance contact faults. It includes motor parameters such as stator resistance, inductance, and nominal value of permanent magnet flux, as well as the high-resistance contact resistance of the fault phase.

[0102] The process of determining the fault-state model expansion equations incorporates the neutral-point offset, as reflected by the neutral-point voltage matrix, into the initial fault-state model, resulting in a set of equations that comprehensively describe the motor's operating characteristics under a fault condition. This fault-state model expansion equations include the relationships between the stator voltage, stator current, electrical angular velocity, motor parameters (at least one of stator resistance, nominal flux linkage, and inductance) and high-resistance contact resistance in the motor's rotating coordinate system, and consider the impact of the fault on motor performance.

[0103] In one embodiment, Figure 3 As shown, based on the neutral point voltage matrix and the initial fault state model, the fault state mathematical model expansion equation group is determined, including the following steps:

[0104] Step 301: Based on the neutral point voltage matrix and the initial fault state mathematical model, construct a fault state transition mathematical model of the multi-phase permanent magnet synchronous motor in a natural coordinate system taking into account the neutral point offset;

[0105] The neutral-point voltage matrix provides information about the neutral-point voltage variation relative to ground, reflecting the degree of neutral-point offset. The initial fault-state mathematical model describes the fundamental electromagnetic relationships in the motor during a fault condition, including parameters such as stator resistance, inductance, permanent magnet flux linkage, and the high-resistance contact resistance of the faulty phase. By combining the neutral-point voltage matrix with the initial fault-state model, a more comprehensive mathematical model of the fault-state transition can be established.

[0106] The fault-state transition mathematical model can more accurately describe the operating characteristics of a multiphase permanent magnet synchronous motor under fault conditions, including the changes in voltage and current for each phase. In the natural coordinate system, the fault-state transition mathematical model preserves the original physical characteristics of the multiphase permanent magnet synchronous motor while also considering the impact of the fault on motor performance. This allows for more accurate analysis and prediction of motor behavior when a fault occurs.

[0107] Step 302: Based on the fault state transition mathematical model and coordinate transformation matrix 、 , construct a fault state mathematical model of a multi-phase permanent magnet synchronous motor considering neutral point offset in a rotating coordinate system;

[0108] To transform the fault state transition mathematical model into a rotating coordinate system, it is necessary to apply the coordinate transformation matrix and . Transformations are often used to convert a natural coordinate system of three or more phases into a stationary coordinate system (e.g. coordinate system), Transformations can be used to convert a stationary coordinate system into a rotating coordinate system (such as coordinate system).

[0109] Through coordinate transformation, the variables such as voltage, current and flux in the natural coordinate system can be converted to the corresponding variables in the rotating coordinate system. The purpose of this is to simplify 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 conversion process, it is necessary to ensure that the effects of neutral point offset are 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 axes. These voltage equations can describe how the voltage on each axis is affected by the motor parameters, high-resistance contact resistance, stator current, and electrical angular velocity, taking into account the neutral point offset.

[0110] Step 303: Determine a fault state mathematical model expansion equation group based on the fault state mathematical model.

[0111] The fault-state mathematical model is a comprehensive mathematical description that covers the key electromagnetic relationships and dynamic behavior of a multiphase permanent magnet synchronous motor under fault conditions. By expanding the voltage equations in the fault-state mathematical model along different coordinate axes, a set of equations is obtained. Each equation corresponds to a coordinate axis and clearly demonstrates the relationship between the voltage on that axis and the motor parameters, high-resistance contact resistance, stator current, and electrical angular velocity.

[0112] 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 follows: Figure 4As shown, a dual closed-loop control structure of speed loop and current loop is adopted. The outer speed loop adopts PI control to generate the fundamental quadrature axis current reference value, and the fundamental quadrature axis current reference value is . Set the fundamental direct axis current , third harmonic direct axis current and the third harmonic quadrature-axis current The reference values are all 0. Using the coordinate transformation matrix and After performing Park inverse transform and Clarke inverse transform, the five-phase current reference values in the natural coordinate system are obtained. The five-phase current reference values are 、 、 、 and , as the input of the inner current loop. The inner current loop uses five parallel PR controllers, whose outputs are the reference values of the five-phase voltages. The reference values of the five-phase voltages are 、 、 、 as well as Finally, through PWM modulation and five-phase inverter, the stable operation of the motor is controlled. When a high-resistance contact fault occurs, the PR controller can effectively suppress torque fluctuations and maintain the consistency of each phase current with the normal operating condition. When the contact resistance exceeds the zero threshold and causes a sudden change in current, it is equivalent to an open circuit fault condition. represents the electrical angular velocity of the five-phase permanent magnet synchronous motor, Represents the electrical angle of the five-phase permanent magnet synchronous motor.

[0113] 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 the neutral point offset in the natural coordinate system is:

[0114] ;

[0115] in, is a matrix composed of high-resistance contact resistance and unit matrix, ; The fault phase is The compensation coefficient matrix of the phase.

[0116] It should be noted that and The specific derivation process is:

[0117] ;

[0118] ;

[0119] .

[0120] by Taking the phase as an example, simplifying the above formula, we can get:

[0121] ;

[0122] ;

[0123] in, , .

[0124] Similarly, it can be deduced that .

[0125] ;

[0126] ;

[0127] In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, the mathematical model expression of the fault state of the five-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system is:

[0128] ;

[0129] in, is the fault state voltage matrix in the rotating coordinate system; is the fault current matrix in the rotating coordinate system; and is the coordinate transformation matrix; is the magnetic flux matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux matrix in the rotating coordinate system; is the electric angular velocity matrix in the rotating coordinate system; The fault phase is The fault correction coefficient matrix when phase is .

[0130] For example, 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 is time-varying, nonlinear, and coupled. Parameter identification in this coordinate system has problems such as large computational complexity and parameter coupling. In order to achieve parameter identification, this application adopts the vector space decoupling method to obtain the decoupling model of the rotating coordinate system. The coordinate transformation of the five-phase permanent magnet synchronous motor is as follows: Figure 5 As shown, 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, such as Figure 5 As shown in (a), is the fundamental wave subspace, and the rotation speed is the fundamental wave electrical angular velocity .like Figure 5 As shown in (b), is the third harmonic subspace, and the rotation speed is the fundamental electrical angular velocity 3 times. By the natural coordinate system Transform to the stationary coordinate system The transformation matrix is The expression is:

[0131] ;

[0132] in, .

[0133] The variables in the stationary coordinate system are rotating variables. To further solve the time-varying coupling problem of rotating motor variables, we use Transform the stationary coordinate system The sine variable is converted into a rotating coordinate system The DC decoupling amount under the coordinate transformation is expressed as follows:

[0134] ;

[0135] in, is the electrical angle.

[0136] For example, the fault state transition mathematical model of the five-phase permanent magnet synchronous motor with neutral point offset is constructed from the natural coordinate system To the rotating coordinate system The coordinate transformation process is as follows:

[0137]

[0138] in,

[0139] ;

[0140] Furthermore, the voltage matrix in the rotating coordinate system is , current matrix in rotating coordinate system , resistance matrix in the rotating coordinate system , inductance matrix in rotating coordinate system , permanent magnet flux matrix in rotating coordinate system , the electric angular velocity matrix in the rotating coordinate system and the failure coefficient matrix The expression is:

[0141] ;

[0142] ;

[0143] ;

[0144] ;

[0145] ;

[0146] ;

[0147] ;

[0148] in, Respectively represent the rotating coordinate system The stator voltage of the shaft, is the zero-sequence voltage; In the rotating coordinate system The stator current of the shaft, is the zero sequence current; 、 are the permanent magnet flux linkages of the fundamental subspace and the third harmonic subspace respectively; In the rotating coordinate system The inductance of the shaft, 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 No. The element corresponding to the first column of the row represents a five-phase permanent magnet synchronous motor When a high-resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis.

[0149] In one embodiment, the expanded equation of the fault state mathematical model of the five-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system is expressed as follows:

[0150] ;

[0151] It should be noted that 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 The associated equation is: The motor parameters corresponding to the axis include Inductance corresponding to the axis 、 Inductance corresponding to the axis and stator resistance .

[0152] 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 The associated equation is: The motor parameters corresponding to the axis include Inductance corresponding to the axis 、 Inductance corresponding to the axis , stator resistance And the nominal value of the permanent magnet flux in the fundamental subspace .

[0153] 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 The associated equation is: The motor parameters corresponding to the axis include Inductance corresponding to the axis 、 Inductance corresponding to the axis and stator resistance .

[0154] 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 The associated equation is: The motor parameters corresponding to the axis include Inductance corresponding to the axis 、 Inductance corresponding to the axis , stator resistance And the nominal value of the permanent magnet flux in the fundamental subspace .

[0155] Furthermore, if Figure 6 As shown, taking the five-phase permanent magnet synchronous motor as an example, the five-phase permanent magnet synchronous motor adopts dual closed-loop vector control of speed loop and current loop. When the motor is in a healthy state, the state variables in the rotating coordinate system are all DC quantities, and the state variables include: current and voltage. Therefore, the state variables of the motor in a healthy state do not change when it is running stably, and one voltage equation can only identify one motor parameter. In a fault state, the voltage of the fault phase increases due to the connection of the high-resistance contact resistance, and the voltage of the other phases decreases, which leads to an imbalance in the stator current and voltage. In the reconstructed rotating coordinate system, the voltage shows a sinusoidal transformation, the current is still a DC quantity, and the current differential term can be ignored. Therefore, in the expanded equation of the fault state mathematical model of the five-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system, each voltage equation can identify two motor parameters at a time. Considering that the five-phase permanent magnet synchronous motor is generally a surface-mounted motor, this type of motor often uses Control. Ignoring the third harmonic reaction potential, Furthermore, the expanded equation of the fault state mathematical model of the five-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system can be simplified as:

[0156] ;

[0157] In one embodiment, the fault state mathematical model is selected to expand the equation group under the rotating coordinate system. The voltage equation corresponding to the axis is used as the target equation; the stator voltage, stator current and electrical angular velocity in the rotating coordinate system corresponding to the target equation are obtained, and the stator voltage, stator current, electrical angular velocity and fault correction coefficient are converted into Input the online resistance identification model and get the resistance matrix:

[0158] Get Stator voltage corresponding to the axis , stator current and electrical angular velocity , the stator voltage , stator current , electrical angular velocity and fault correction factor Input 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 fault phase.

[0159] The stator voltage , stator current , electrical angular velocity and fault correction factor Input online resistance identification model. Fault correction factor It is based on the position of the fault phase and the fault correction coefficient matrix Extracted, used to adjust the fault phase The voltage equation on the shaft is used to compensate for the fault's impact on motor performance. The online resistance identification model uses this input data to calculate a resistance matrix using a recursive least squares method. The resistance matrix contains estimates of the stator resistance and the high-resistance contact resistance of the faulty phase. The stator resistance reflects the motor's resistance characteristics during normal operation, while the high-resistance contact resistance represents the increased resistance of the faulty phase due to poor contact.

[0160] In one embodiment, the expression of the online resistance identification model includes an input matrix of the online resistance identification model, a coefficient matrix of the online resistance identification model, and an output of the online resistance identification model;

[0161] 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, which is equal to the resistance matrix; , , .

[0162] in yes The stator voltage of the shaft, yes The stator current of the shaft, for The fault correction factor corresponding to the axis, is the electrical angular velocity of the motor, is the nominal value of the fundamental permanent magnet flux linkage. Input matrix Contains two key variables that affect the output: stator current and fault correction factor , which are presented in the form of row vectors. The coefficient matrix The stator resistance and high-resistance contact resistance of the fault phase These two parameters are the core unknowns of the model and need to be determined by identifying the model.

[0163] Output of the online resistance identification model In fact, the form obtained by transforming and sorting the voltage equation of the motor is input into the matrix Elements and They correspond to the stator current and fault correction coefficient in the equation respectively, and the coefficient matrix Elements and The corresponding stator resistance and high-resistance contact resistance of the fault phase are obtained by online resistance identification model and combined with the nominal value of fundamental flux linkage. , the phase voltage and phase current measured in real time are obtained after coordinate transformation and , the differential of the electrical angle measured in real time by the position sensor , calculate the resistance matrix , and then get the stator resistance and high-resistance contact resistance of the fault phase The specific value of .

[0164] In one embodiment, taking a five-phase permanent magnet synchronous motor as an example, assuming that the five-phase permanent magnet synchronous motor For example, a high-resistance contact fault occurs in the phase. Figure 4 The vector control block diagram of a five-phase permanent magnet synchronous motor is constructed in Matlab / Simulink, including modules such as the speed loop PI controller, current loop PR controller, PWM modulation, five-phase inverter, and motor mathematical model to achieve stable operation of the motor. The motor parameters and other simulation parameters used in the simulation are shown in the following table:

[0165]

[0166] Set the simulation speed to , A high-resistance contact fault occurs in the phase. When a high-resistance contact fault occurs, the current loop adopts the above-mentioned PR controller. At this time, the five-phase current is consistent with the current under healthy conditions. However, due to the connection of the fault resistor, 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 fault of the multi-phase permanent magnet synchronous motor proposed in this application, the parameter identification simulation results of the high-resistance contact resistance and stator winding resistance are as follows Figure 7 shown. Figure 7 (a) The vertical axis is the high-resistance contact resistance value, and the horizontal axis is time; Figure 7 In (b), the vertical axis is the stator resistance and the horizontal axis is time. Figure 7 (a) is the identification simulation result of high-resistance contact resistance. In 0.1s, the high-resistance contact resistance in the healthy state Sudden change to high resistance contact resistance , in 0.5s the high resistance contact resistance suddenly changes to The simulation identification error is 2.5%, and it can respond quickly when the high-resistance contact resistance suddenly changes, with good dynamic performance and accuracy. Figure 7 (b) in the figure is the identification result of the stator resistance. The identification error is less than 2.3%, which achieves accurate identification of the stator resistance and the fault contact resistance does not affect the identification accuracy of the stator resistance.

[0167] Based on the same concept, an embodiment of the present application also provides an online resistance identification system for high-resistance contact fault of a multi-phase permanent magnet synchronous motor. The system includes a multi-phase permanent magnet synchronous motor and a controller, and the controller can execute the above-mentioned online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor.

[0168] The controller constructs a fault-state transition mathematical model based on the neutral-point voltage matrix and the initial fault-state model, then transforms it into a fault-state mathematical model in a rotating coordinate system using a coordinate transformation matrix. Furthermore, the voltage equation corresponding to one of the axes in the expanded set of equations is selected as the target equation. The corresponding stator voltage, stator current, electrical angular velocity, and fault correction coefficient are input into the online resistance identification model to calculate a resistance matrix that includes the stator resistance and the high-resistance contact resistance of the fault phase.

[0169] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0170] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor, characterized in that: The method comprises: In response to a high-resistance contact fault of the multi-phase permanent magnet synchronous motor, determining a fault phase position where the high-resistance contact fault occurs; the fault phase position is any phase of the multi-phase permanent magnet synchronous motor; According to the fault phase position, select the corresponding compensation coefficient matrix , the compensation coefficient matrix The multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase matrix; According to the compensation coefficient matrix Combine the stator current and coordinate transformation matrix to calculate the corresponding fault correction coefficient matrix , from the fault correction coefficient matrix Extract the fault correction factor from ; The fault correction factor is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents the multi-phase permanent magnet synchronous motor When a high resistance contact fault occurs in the phase Fault correction coefficient of the voltage equation corresponding to the axis; Obtain the fault state mathematical model expansion equation group of the multi-phase permanent magnet synchronous motor considering the neutral point offset in the rotating coordinate system; the fault state mathematical model expansion equation group includes The voltage equation corresponding to the axis; the voltage equation is the voltage equation in the rotating coordinate system Equations related to the stator voltage, stator current, electrical angular velocity, motor parameters, and high-resistance contact resistance corresponding to the axis; Selecting at least one voltage equation in the expanded equation group of the fault state mathematical model as a target equation, and determining an online resistance identification model that satisfies a recursive least squares method based on the target equation; Get the target equation corresponding to The stator voltage, stator current and electrical angular velocity of the shaft are converted into the stator voltage, the stator current, the electrical angular velocity and the fault correction coefficient. The online resistance identification model is input to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the fault phase.

2. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 1 is characterized in that: Obtaining an expanded set of equations for a fault state mathematical model of the multi-phase permanent magnet synchronous motor taking into account neutral point offset in a rotating coordinate system, including: Constructing an initial fault state model of the multi-phase permanent magnet synchronous motor in a natural coordinate system; Determining a neutral point voltage matrix of the multi-phase permanent magnet synchronous motor based on an offset of a neutral point of the multi-phase permanent magnet synchronous motor, wherein the neutral point voltage matrix is a neutral point-to-ground voltage matrix; Based on the neutral point voltage matrix and the initial fault state model, a fault state model expansion equation group is determined.

3. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 2, characterized in that: Based on the neutral point voltage matrix and the initial fault state model, a fault state mathematical model expansion equation group is determined, including: Based on the neutral point voltage matrix and the initial fault state mathematical model, constructing a fault state transition mathematical model of the multi-phase permanent magnet synchronous motor taking into account the neutral point offset in a natural coordinate system; Based on the fault state transition mathematical model and coordinate transformation matrix 、 , constructing a fault state mathematical model of the multi-phase permanent magnet synchronous motor taking into account neutral point offset in a rotating coordinate system; The fault state mathematical model expansion equation group is determined based on the fault state mathematical model.

4. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 2, characterized in that: The neutral point voltage matrix of the multi-phase permanent magnet synchronous motor is expressed as follows: ； in, is the number of phases of the multiphase permanent magnet synchronous motor, The fault phase is The neutral point to ground voltage matrix of the phase, The fault phase is The fault phase current when the phase The fault phase is High-resistance contact resistance during phase transition.

5. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 3, characterized in that: The expression of the fault state transition mathematical model of the multi-phase permanent magnet synchronous motor considering the neutral point offset in the natural coordinate system is: ； in, Represents the terminal voltage matrix of the multi-phase permanent magnet synchronous motor in fault state; Represents the phase current matrix of the multi-phase permanent magnet synchronous motor in a fault state; is the stator resistance matrix, , is the stator resistance, for Identity matrix; is a matrix composed of high-resistance contact resistance and unit matrix, ; The fault phase is Phase compensation coefficient matrix; is the stator flux matrix, , is the stator inductance matrix, is the permanent magnet flux matrix, Represents the differential symbol.

6. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 3, characterized in that: The expression of the fault state mathematical model is: ； ； in, is the fault state voltage matrix in the rotating coordinate system; is the fault current matrix in the rotating coordinate system; and is the coordinate transformation matrix; is the magnetic flux matrix in the rotating coordinate system, ; is the inductance matrix in the rotating coordinate system, is the permanent magnet flux matrix in the rotating coordinate system; is the electric angular velocity matrix in the rotating coordinate system; The fault phase is The fault correction coefficient matrix when the phase is, is the fault correction coefficient matrix No. The element corresponding to the first column of the row represents the multi-phase permanent magnet synchronous motor When a high-resistance contact fault occurs in the phase Fault correction factor of the voltage equation corresponding to the axis.

7. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 1, characterized in that: The expression of the expansion equation of the fault state mathematical model is: in, represents the electrical angular velocity of the multi-phase permanent magnet synchronous motor, Respectively represent the rotating coordinate system The stator voltage of the shaft, In the rotating coordinate system The stator current of the shaft, 、 , … for k The permanent magnet flux linkage in the subharmonic subspace, In the rotating coordinate system The inductance of the shaft.

8. The online resistance identification method for high-resistance contact fault of a multi-phase permanent magnet synchronous motor according to claim 1, characterized in that: Select the fault state mathematical model to expand the equation group in the rotating coordinate system The voltage equation corresponding to the axis is used as the target equation; Obtain the stator voltage, stator current and electrical angular velocity corresponding to the target equation, and convert the stator voltage, the stator current, the electrical angular velocity and the fault correction coefficient Input the online resistance identification model and obtain the resistance matrix: Get Stator voltage corresponding to the axis , stator current and electrical angular velocity , the stator voltage , the stator current , the electrical angular velocity and the fault correction factor The online resistance identification model is input to obtain a resistance matrix; the resistance matrix includes the stator resistance and the high-resistance contact resistance of the fault phase.

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

10. An online resistance identification system for high-resistance contact fault of a multi-phase permanent magnet synchronous motor, characterized in that: The system includes a multi-phase permanent magnet synchronous motor and a controller, wherein the controller is capable of executing the online resistance identification method for high-resistance contact fault of the multi-phase permanent magnet synchronous motor according to any one of claims 1 to 9.

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