System and method for detecting operational failures of a synchronous motor

Abstract

The present disclosure provides a system and method for detecting faults in the operation of a synchronous motor. The method includes collecting an electrical input and a measurement associated with the operation of the synchronous motor caused by the electrical input. The method further includes determining a series of points defining a mutual position of a stator and a rotor of the synchronous motor that results in a static magnetic field determined as a weighted sum over a real space basis function, the real space basis function being parameterized with pairs of adjacent points in the determined series of points and weighted with a surface charge density between corresponding adjacent points, the static magnetic field describing the measurement of the operation of the synchronous motor taking into account the electrical input. Furthermore, the method includes determining a fault in the operation of the synchronous motor based on the mutual position of the stator and the rotor of the synchronous motor.

Description

[Technical Field]

[0001] This disclosure generally relates to synchronous motors such as reluctance motors and permanent magnet motors, and more specifically to a system and method for detecting operational failures of synchronous motors. [Background technology]

[0002] Synchronous motors are widely used in a variety of industrial applications, including pumps, chemicals, petrochemicals, and electrified transportation systems. In many applications, synchronous motors operate under several unfavorable conditions, such as high ambient temperature, high humidity, and overload, which can result in malfunctions that lead to high maintenance costs and serious economic losses due to unexpected downtime.

[0003] The causes of malfunction in synchronous motors are generally a variety of failures, including drive inverter failure, stator winding insulation breakdown, broken rotor bar failure, and other mechanical failures. Several studies on synchronous machine failures conducted by the IEEE Industry Application Society (IEEE-IAS) and the Japan Electrical Manufacturers' Association (JEMA) have revealed that mechanical failures are the most common type of failure. Examples of mechanical failures include bearing failures and / or eccentric failures in synchronous motors. [Overview of the project] [Problems that the invention aims to solve]

[0004] Bearing failures can be detected by vibration and acoustic analysis. However, the accuracy of bearing failure diagnosis based on vibration or acoustic signals can be affected by background noise caused by external mechanical excitation motion, while its sensitivity also varies depending on the sensor's installation location. An alternative method for bearing failure detection is achieved by analyzing the stator current of a synchronous motor. However, the magnitude of the stator current at the bearing failure signature frequency can vary with different loads, speeds, and power ratings of the synchronous motor itself, thus creating the challenge of identifying a threshold stator current value to trigger a failure alarm under arbitrary operating conditions.

[0005] Similarly, eccentric failures in synchronous motors have been thoroughly studied over the past several decades. Eccentric failures can exist in both static and dynamic forms, called static eccentricity, dynamic eccentricity, or mixed eccentric failures. Eccentric failures cause stator-rotor friction that can lead to bearing damage, excessive vibration and noise, unbalanced synchronous pull, and, under extreme conditions, damage to the synchronous motor. Eccentric failures may cause bearing failures, or may be caused by bearing failures. Therefore, theoretically, similar failure detection methods can be applied to detect eccentric failures in synchronous motors. However, in practice, different types of failures in synchronous motors are difficult to detect, so different techniques are adapted to detect different types of failures.

[0006] Therefore, there is a need to provide methods for detecting different types of failures in synchronous motors.

[0007] The objective of some embodiments is to provide systems and methods for determining different types of failures in the operation of a synchronous motor. Examples of synchronous motors include reluctance motors and permanent magnet motors. Examples of failures include mechanical failures, including different types of bearing failures and different types of eccentric failures. In addition to or instead of this, the objective of some embodiments is to provide methods that can determine different types of failures from the same input. In addition to or instead of this, the objective of some embodiments is to provide methods that can determine different types of eccentric failures in a synchronous motor, such as static eccentricity, dynamic eccentricity, or both. [Means for solving the problem]

[0008] A synchronous motor includes a stator and a rotor separated by an air gap. Some embodiments are based on the understanding that a synchronous motor includes interfaces between different materials of the synchronous motor. For example, a synchronous motor includes two interfaces. The first interface is between the stator of the synchronous motor and the air in the air gap, and the second interface is between the air in the air gap and the rotor of the synchronous motor. The first interface between the stator and the air in the air gap is a sequence of points, for example, z0, z1, z2, z3, ..., z N Represented by, the second interface between the air in the air gap and the rotor is another continuum of points, for example, y0, y1, y2, y3, ..., y N This is represented by [the following equation]. In this way, the continuity of these points forms the interface between the different materials of the synchronous motor. Furthermore, the continuity of points determines the relative positions of the stator and the rotor.

[0009] Some embodiments are based on the understanding that a structural defect in a synchronous motor resulting in misalignment between the rotor and stator positions causes failure. In other words, this defect results in a change in the relative position of the stator and rotor. Different types of defects result in different relative positions of the stator and rotor. Therefore, if the relative position of the stator and rotor can be determined online from measurements of the synchronous motor's operation, then this relative position can be used to detect different types of failures. However, determining the relative position of the stator and rotor is memory and computationally expensive. Therefore, an objective of some embodiments is to provide a practical method suitable for online estimation of the structure of a synchronous motor for determining the relative position of the stator and rotor.

[0010] Some embodiments are based on the understanding that the structure of a synchronous motor can be represented by the material distribution of its components during operation. For example, the magnetic field distribution can be determined using the principle of static magnetic fields, which can be used to explain the operation of a synchronous motor. As a result, the principle of static magnetic fields can be used to link the structure of a synchronous motor to its operation, and therefore can be used to analyze the structure of a synchronous motor during its operation.

[0011] Magnetostatics is the study of magnetic fields in systems where the electric current is in a steady state (does not change over time). Magnetostatics is the magnetic equivalent of electrostatics where the charge is stationary. However, in many cases, magnetization does not need to be static, and the equations for static magnetic fields can be used to predict high-speed synchronous switching events occurring on sub-nanosecond timescales. Static magnetic fields are even a sufficient approximation when the current is not static, as long as the current is not rapidly alternating. Static magnetic fields are typically used in micromagnetism applications, such as models of magnetic memory devices in computer memory, but static magnetic field focusing can be achieved by a permanent magnet or by passing a current through a coil of wire whose axis coincides with the beam axis. Therefore, static magnetic fields can be used to analyze the structure of synchronous motors.

[0012] Some embodiments are based on the understanding that, based on the principle of static magnetic fields, the relative positions of the stator and rotor can be learned online to explain the electrical output corresponding to the electrical input. Specifically, some embodiments are based on the understanding that there is a relationship between the relative positions of the stator and rotor of a synchronous motor and the static magnetic field. In addition, some embodiments are based on the understanding that there is a relationship between the electrical input, the static magnetic field generated by the synchronous motor in response to the electrical input, and the electrical output or measured value of the synchronous motor's operation. Therefore, different static magnetic fields are required for different relative positions of the stator and rotor. Furthermore, a static magnetic field is selected to explain the electrical output considering the electrical input. The relative positions corresponding to the selected static magnetic field are the current / actual relative positions.

[0013] In this way, by evaluating different relative positions of the stator and rotor, the relative position of the stator and rotor that best matches the electrical output considering the electrical input can be determined using a static magnetic field. Furthermore, based on the determined relative position of the stator and rotor, faults can be identified. However, this requires an efficient and compact representation of the static magnetic field.

[0014] For example, a static magnetic field can be estimated using finite element analysis (FEA) and / or finite difference analysis, which can be considered a variation of FEA. However, FEA typically solves potentials that require boundary values ​​at locations larger than the region of interest. As a result, the static magnetic field obtained using FEA is represented as a set of points in the space surrounding and containing the synchronous motor. Such a representation is inconvenient and memory-intensive. For example, the FEA method requires at least 5000 points to represent a simple cylindrical motor.

[0015] Another method for determining the static magnetic field is to use the eigenfunction expansion (EE) method. The EE method expresses the solution in terms of eigenfunctions and automatically satisfies the partial differential equation. However, the EE method only works for motors whose component geometry coincides with polar coordinates. Therefore, in order to use the EE method, the shape of any component of the motor must be approximated as a sector and / or combination of sectors, which is not always practical.

[0016] Therefore, there is a need for a 2D magnetic field alternative solver suitable for online fault detection during synchronous motor operation, and an efficient and compact representation of the static magnetic field discovered using this solver.

[0017] Some embodiments are based on the understanding that the static magnetic field can be expressed as a weighted sum over real-space basis functions. Each real-space basis function is analytical, parameterized by a continuum of points forming the interface of different materials inside a synchronous motor, and weighted by the surface charge density. Specifically, the real-space basis functions are parameterized by pairs of adjacent points, for example, points z1 and z2 in a continuum of points, and weighted by the surface charge density between the corresponding adjacent points, for example, the surface charge density between points z1 and z2. According to one embodiment, the surface charge density is obtained by iteratively matching the boundary conditions for the interface imposed by Maxwell's equations. The representation of the static magnetic field as a weighted sum over real-space basis functions provides a compact representation of the static magnetic field. In addition, such a representation is independent of the motor load.

[0018] Therefore, different static magnetic fields for different relative positions at different points in time are obtained by parameterizing a sequence of points representing the interface between different materials for each relative position and calculating a weighted sum over real-space basis functions, weighted by surface charge density. Furthermore, a static magnetic field is selected to describe the electrical output considering the electrical input. In addition, the sequence of points defining the relative positions of the stator and rotor is determined from the selected static magnetic field. Moreover, failures in the operation of the synchronous motor are determined based on the relative positions of the stator and rotor.

[0019] In this way, some embodiments use a novel representation of the static magnetic field of a synchronous motor as a weighted sum over real-space basis functions. Furthermore, such a representation of the static magnetic field is a compact and memory-efficient representation of the static magnetic field and is suitable for online control or monitoring of synchronous motors. This improvement allows some embodiments to design fault detectors suitable for online estimation of different types of faults in synchronous motors.

[0020] Therefore, one embodiment discloses a fault detection device for detecting operational failures of a synchronous motor including a stator and rotor separated by an air gap. The fault detector comprises a processor and a memory storing instructions, which, when executed by the processor, cause the fault detector to collect electrical inputs for controlling the operation of a synchronous motor and measurements of the operation of the synchronous motor caused by the electrical inputs, and to determine a continuum of points, which is a continuum of points that defines the relative positions of the stator and rotor of the synchronous motor and forms the interface of different materials inside the synchronous motor that gives rise to a static magnetic field, which is obtained as a weighted sum over real-space basis functions, the real-space basis functions are parameterized by pairs of adjacent points in the determined continuum of points and weighted by the surface charge density between the corresponding adjacent points, the static magnetic field describes the measurements of the operation of the synchronous motor considering the electrical inputs, and further causes the fault detector to determine a fault in the operation of the synchronous motor based on the relative positions of the stator and rotor of the synchronous motor, and to transmit, via the communication channel, either or a combination of an indication of a fault in the operation of the synchronous motor and a control command selected based on the fault.

[0021] Accordingly, another embodiment discloses a method for detecting operational failures of a synchronous motor including a stator and rotor separated by an air gap. The method includes collecting electrical inputs for controlling the operation of the synchronous motor and measurements of the operation of the synchronous motor caused by the electrical inputs via a communication channel including one or a combination of a wired communication link and / or a wireless communication link; determining a continuum of points, which is a continuum of points that defines the relative positions of the stator and rotor of the synchronous motor and forms the interfaces of different materials inside the synchronous motor that result in a static magnetic field, which is obtained as a weighted sum over real-space basis functions, the real-space basis functions being parameterized by pairs of adjacent points in the determined continuum of points and weighted by the surface charge density between the corresponding adjacent points, the static magnetic field describing the measurements of the operation of the synchronous motor considering the electrical inputs; further, determining an operational failure of the synchronous motor based on the relative positions of the stator and rotor of the synchronous motor; and transmitting one or a combination of an indication of an operational failure of the synchronous motor and / or a control command selected based on the failure via the communication channel.

[0022] Thus, another embodiment discloses a non - transient computer - readable storage medium including a program executable by a processor to perform a method for detecting a fault in the operation of a synchronous motor including a stator and a rotor separated by an air gap. The method includes collecting an electrical input for controlling the operation of the synchronous motor and a measurement of the operation of the synchronous motor caused by the electrical input via a communication channel including one or a combination of a wired communication link and a wireless communication link, determining a sequence of points, the sequence of points defining the relative position of the stator and the rotor of the synchronous motor and forming an interface of different materials inside the synchronous motor that results in a static magnetic field obtained as a weighted sum over real - space basis functions, the real - space basis functions being parameterized by pairs of adjacent points among the determined sequence of points and weighted by the surface charge density between the corresponding adjacent points, the static magnetic field explaining the measurement of the operation of the synchronous motor considering the electrical input, and further, based on the relative position of the stator and the rotor of the synchronous motor, determining a fault in the operation of the synchronous motor, and transmitting, via the communication channel, one or a combination of a display of the fault in the operation of the synchronous motor and a control command selected based on the fault.

[0023] The embodiments disclosed herein will be further described with reference to the accompanying drawings. The drawings shown are not necessarily to scale; instead, emphasis is generally placed on explaining the principles of the embodiments disclosed herein.

Brief Description of the Drawings

[0024] [Figure 1A] A schematic diagram of a synchronous motor according to an embodiment of the present disclosure is shown. [Figure 1B] A detailed block diagram of a fault detector for detecting a fault in the operation of a synchronous motor according to an embodiment of the present disclosure is shown. [Figure 2A] Schematic diagrams explaining a normal synchronous motor according to some embodiments of the present disclosure are shown. [Figure 2B] Schematic diagrams explaining a static eccentricity fault according to some embodiments of the present disclosure are shown. [Figure 2C] A schematic diagram illustrating a dynamic eccentric failure according to some embodiments of this disclosure is shown. [Figure 2D] A schematic diagram illustrating a mixture of both static and dynamic eccentric faults, as described in some embodiments of this disclosure, is shown. [Figure 3] A schematic diagram illustrating the interfaces of different materials inside a synchronous motor according to some embodiments of this disclosure is shown. [Figure 4] A schematic diagram illustrating the use of a static magnetic field for analyzing the structure of a synchronous motor, according to some embodiments of this disclosure, is shown. [Figure 5] A block diagram is shown of a method for determining the continuity of points that define the relative positions of the stator and rotor of a synchronous motor, according to one embodiment of the present disclosure. [Figure 6] A block diagram of a method for determining the continuity of points that define the relative positions of the stator and rotor of a synchronous motor, according to another embodiment of the present disclosure, is shown. [Figure 7] This figure shows a tabular column of an example of data stored in the memory of a fault detector according to one embodiment of the present disclosure. [Figure 8] A schematic diagram of a classifier for classifying the type and severity of a failure, according to one embodiment of this disclosure, is shown. [Figure 9] A block diagram illustrating an H-solver according to one embodiment of this disclosure is shown. [Figure 10] A block diagram illustrating a B-solver according to one embodiment of this disclosure is shown. [Figure 11] A block diagram illustrating a BH solver according to one embodiment of this disclosure is shown. [Figure 12A] This figure shows the geometric shape of a finite-thickness cylinder according to one embodiment of the present disclosure. [Figure 12B] This figure shows tabular columns illustrating a comparison of results from different solvers according to one embodiment of the present disclosure. [Figure 13A] A schematic diagram illustrating the geometric shape of a rotor according to one embodiment of this disclosure is shown. [Figure 13B]This figure shows a graph of torque as a function of electrical angle according to one embodiment of the present disclosure. [Figure 14] A block diagram of a method for detecting operational failures of a synchronous motor according to one embodiment of the present disclosure is shown. [Figure 15] This is a schematic diagram illustrating a computing device that can be used to implement the system and method of this disclosure. [Modes for carrying out the invention]

[0025] The following details are provided for explanatory purposes to ensure that this disclosure is fully understood. However, it will be apparent to those skilled in the art that this disclosure can be implemented without these details. In other cases, the apparatus and methods are shown in block diagram form solely to avoid obscuring this disclosure.

[0026] The terms “for example,” “for instance,” and “such as,” as used herein and in the claims, as well as the verbs “comprising,” “having,” and “including,” and each of these verbs in other forms, should be interpreted as open-ended, meaning that when used with an enumeration of one or more components or other items, the enumeration should not be considered to exclude any further components or items. The term “based on” means based at least partially. Furthermore, it should be understood that the style and terminology used herein are for illustrative purposes only and should not be considered restrictive. Any headings used herein are for convenience only and have no legal or restrictive effect.

[0027] Figure 1A shows a schematic diagram of a synchronous motor 101 according to one embodiment of the present disclosure. The synchronous motor 101 is an AC motor in which the rotation of its shaft is synchronized with the frequency of the supplied current in a steady state. Examples of synchronous motors include reluctance motors and permanent magnet motors. The synchronous motor 101 includes a stator 103, a rotor 105, a main shaft 107, and two bearings 109A and 109B. Sensors 111A, 111B, and 111C are connected to the synchronous motor 101. According to a particular embodiment, sensors 111A, 111B, and 111C may be current and voltage sensors for obtaining the current and voltage of each winding of the synchronous motor 101. Other sensors are intended, including torque sensors, environmental sensors (temperature, humidity, etc.), and other types of sensors used to assist in the operation, maintenance, or management of the synchronous motor 101.

[0028] A fault detector 113 is connected to the synchronous motor 101. The fault detector 113 is configured to detect malfunctions in the operation of the synchronous motor 101. Sensor data collected from sensors 111A, 111B, and 111C are input to the input interface 115 of the fault detector 113. The sensor data can also be stored in the memory 117. The sensor data is then processed by the processor 119 and can be output to the output interface 121 or stored in the memory 117 of the fault detector 113, depending on the user's purpose / interest. Details of the fault detector 113 will be described later with reference to Figure 1B.

[0029] Figure 1B shows a detailed block diagram of a fault detector 113 according to one embodiment of the present disclosure. The fault detector 113 includes a network interface controller (NIC) 123 adapted to connect the fault detector 113 to a network 127 (also called a communication channel) via a bus 125. Via the network 127, either wirelessly or via a wired link, the fault detector 113 collects electrical inputs 129 for controlling the operation of a synchronous motor 101 and measurements of the operation of the synchronous motor 101 caused by the electrical inputs. The electrical inputs include either or a combination of current and / or voltage of each winding, and the measurements include either or a combination of output torque and mutual inductance between different windings.

[0030] Furthermore, in some implementations, a human-machine interface (HMI) 131 within the fault detector 113 connects the fault detector 113 to a keyboard 133 and a pointing device 135. The pointing device 135 may include, among other things, a mouse, trackball, touchpad, joystick, pointing stick, stylus, or touchscreen. In addition, the fault detector 113 includes an application interface 137 for connecting the fault detector 113 to an application device 139 for performing various operations. The fault detector 113 may also include a control interface 141 for connecting the fault detector 113 to a synchronous motor 101. For example, the fault detector 113 can control the synchronous motor 101 via the control interface 141. In addition, the fault detector 113 may be connected via a bus 125 to a display interface 143 adapted to connect the fault detector 113 to a display device 145, such as a computer monitor, television, projector, or mobile device.

[0031] The fault detector 113 further includes a processor 119 and a memory 117 that stores instructions that the processor 119 can execute. The processor 119 may be a single-core processor, a multi-core processor, a computing cluster, or any number of other configurations. The memory 117 may include random-access memory (RAM), read-only memory (ROM), flash memory, or any other suitable memory system. The processor 119 is connected to one or more input and output devices via a bus 125. The stored instructions implement a method for detecting faults in the operation of the synchronous motor 101.

[0032] The processor 119 is configured to detect operational failures of the synchronous motor 101. Failures include, for example, mechanical failures, including different types of bearing failures and different types of eccentric failures of the synchronous motor 101. Different types of bearing failures include cage defects, outer ring defects, inner ring defects, and ball defects. Different types of eccentric failures include, for example, static eccentric failures, dynamic eccentric failures, or both.

[0033] Figures 2A to 2D are schematic diagrams illustrating different types of eccentric failures according to some embodiments of the present disclosure. Any synchronous motor, such as synchronous motor 101, includes a stator 103 and a rotor 105 separated by an air gap 201 between them. Eccentric failure is a type of motor failure resulting from the formation of an uneven air gap between the stator 103 and the rotor 105. Figure 2A shows a normal synchronous motor 101. Point Ow is the center of rotation, point Os is the center of the stator 103, and point Or is the center of the rotor 105. When the three points Ow, Os, and Or coincide, the synchronous motor 101 is normal and there is no eccentric failure.

[0034] Figure 2B is a schematic diagram illustrating a static eccentric fault according to some embodiments of the present disclosure. Points Or and Ow coincide but are offset from the stator center Os. Since the rotor 105 always rotates around the center point Ow, a static eccentric fault exists, and the air gap 201 between the stator 103 and the rotor 105 is not uniform in different places.

[0035] Figure 2C is a schematic diagram illustrating a dynamic eccentric failure according to some embodiments of the present disclosure. The rotation center Ow of the rotor 105 is aligned with the stator center Os, but the rotor center Or revolves around point Ow. Since the rotor 105 does not rotate around its own center of mass, the air gap length 201 varies dynamically with respect to the rotation angle of the rotor 105.

[0036] Figure 2D is a schematic diagram illustrating a mixture of static and dynamic eccentric faults, known as mixed eccentricity, according to some embodiments of this disclosure. Points Or, Os, and Ow are not aligned with each other. In this case, both static and dynamic eccentric faults are present. From the faults shown in Figures 2B to 2D, it can be seen that the air gap 201 is not uniform, i.e., there is an asymmetry in the air gap.

[0037] According to one embodiment, the synchronous motor 101 includes interfaces between different materials of the synchronous motor 101. Figure 3 shows a schematic diagram illustrating interfaces between different materials inside the synchronous motor 101 according to some embodiments of the present disclosure. Here, there are two interfaces between the different materials of the synchronous motor 101. The first interface 301 is between the stator 103 and the air in the air gap 201, and the second interface 303 is between the air in the air gap 201 and the rotor 105. The first interface 301 between the stator 103 and the air in the air gap 201 is a single continuum of points, for example, z0, z1, z2, z3, ..., z N Represented by the second interface 303 between the air in the air gap 201 and the rotor 105, the second interface 303 is another continuum of points, for example, y0, y1, y2, y3, ..., y N This is represented by the following. Thus, the continuity of these points forms the interface between the different materials of the synchronous motor 101. Furthermore, the continuity of points determines the relative positions of the stator 103 and the rotor 105.

[0038] Some embodiments are based on the understanding that a structural defect in the synchronous motor 101 that results in misalignment between the rotor position and the stator position causes failure. In other words, this defect results in a change in the relative position of the stator 103 and the rotor 105. Different types of defects result in different relative positions of the stator 103 and the rotor 105. Therefore, if the relative position of the stator 103 and the rotor 105 can be determined online from collected measurements, then different types of failures can be detected using the relative position of the stator 103 and the rotor 105. However, determining the relative position of the stator 103 and the rotor 105 is memory and computationally expensive. Therefore, an objective of some embodiments is to provide a practical method suitable for online estimation of the structure of the synchronous motor 101 for determining the relative position of the stator 103 and the rotor 105.

[0039] Some embodiments are based on the understanding that the structure of a synchronous motor 101 can be represented by the material distribution of its components during operation. For example, the magnetic field distribution can be determined using the principle of static magnetic fields, which can be used to explain the operation of the synchronous motor 101. As a result, the principle of static magnetic fields can be linked to the structure of the synchronous motor 101 and, therefore, can be used to analyze the structure of the synchronous motor 101 during its operation.

[0040] Magnetostatics is the study of magnetic fields in systems where the electric current is in a steady state (does not change over time). Magnetostatics is the magnetic equivalent of electrostatics where the charge is stationary. The magnetization does not need to be static; the equations of the static magnetic field can be used to predict high-speed synchronous switching events occurring on sub-nanosecond timescales. The static magnetic field is even a sufficient approximation when the current is not static, as long as the current is not rapidly alternating. While static magnetic fields are typically used in micromagnetism applications such as models of magnetic memory devices in computer memory, static magnetic field focusing can be achieved by a permanent magnet or by passing a current through a coil of wire whose axis coincides with the beam axis. Therefore, the static magnetic field can be used to analyze the structure of the synchronous motor 101.

[0041] Figure 4 shows a schematic diagram of the use of a static magnetic field to analyze the structure of a synchronous motor 101 according to some embodiments of this disclosure. Some embodiments are based on the understanding that, based on the principle of a static magnetic field, the electrical output corresponding to the electrical input can be explained by learning the relative positions of the stator 103 and rotor 105 online. Specifically, some embodiments are based on the understanding that there is a relationship between the relative positions 407 of the stator 103 and rotor 105 of the synchronous motor 101 and the static magnetic field 403. In addition, some embodiments are based on the understanding that there is a relationship between the electrical input 401, the static magnetic field 403 generated by the synchronous motor 101 in response to the electrical input, and the electrical output or measured value 405 of the operation of the synchronous motor 101. Therefore, different static magnetic fields are required for different relative positions of the stator 103 and rotor 105. Furthermore, a static magnetic field is selected to explain the electrical output 405 considering the electrical input 401. The relative positions corresponding to the selected static magnetic field are the current / actual relative positions.

[0042] In this way, by evaluating the different relative positions 407 between the stator 103 and the rotor 105, the relative positions of the stator 103 and the rotor 105 that explain the electrical output 405 considering the electrical input 401 can be determined using the static magnetic field 403. Furthermore, based on the determined relative positions of the stator 103 and the rotor 105, a fault can be determined. However, to do so, an efficient and compact representation of the static magnetic field is necessary.

[0043]

number

[0044] Here, each real space basis function [B r (Z|{z i},{λ i}) is analytical, and the continuity of points that form the interface of different materials inside the synchronous motor 101 [{z i It is parameterized by}]. Specifically, each real-space basis function is parameterized by a pair of adjacent points, for example, points z1 and z2 of a continuum of points, and weighted by the surface charge density between the corresponding adjacent points, for example, the surface charge density between points z1 and z2. The surface charge density is obtained by iteratively matching the boundary conditions on the interface imposed by Maxwell's equations. The method for obtaining the surface charge density is explained in Figure 9. From (1), it can be seen that the magnetic field at any point on a two-dimensional plane can be obtained by a weighted sum over real-space basis functions using a continuum of points and the corresponding surface charge density as input parameters for the real-space basis functions. The representation of the static magnetic field as a weighted sum over real-space basis functions provides a compact representation of the static magnetic field. In addition, such a representation is independent of the motor load.

[0045] Therefore, the processor 119 determines different static magnetic fields for different relative positions at different time points by calculating a weighted sum over real-space basis functions, which are parameterized for each relative position by a continuum of points representing the interface between different materials and weighted by the surface charge densities corresponding to various pairs of adjacent points in the continuum of points. The processor 119 further selects a static magnetic field that describes the electrical output 405, taking into account the electrical input 401. Furthermore, from the selected static magnetic field, the processor 119 determines the continuum of points that define the relative positions of the stator 103 and the rotor 105. Furthermore, the processor 119 determines a failure in the operation of the synchronous motor 101 based on the relative positions of the stator 103 and the rotor 105.

[0046] The entire method for determining the continuity of points that define the relative positions of the stator 103 and the rotor 105 will be explained below with reference to Figure 5.

[0047] Figure 5 shows a block diagram of a method 500 for determining a continuum of points that define the relative positions of the stator 103 and rotor 105 of a synchronous motor 101, according to one embodiment of the present disclosure. In block 501, the method 500 includes determining different static magnetic fields based on different relative positions of the stator 103 and rotor 105. According to one embodiment, a processor 119 calculates the different static magnetic fields by calculating a weighted sum over real-space basis functions for each relative position, the real-space basis functions being parameterized by a continuum of points representing the interface between different materials inside the synchronous motor 101, and weighted by the surface charge density corresponding to various pairs of adjacent points in the continuum of points.

[0048] In block 503, method 500 includes the processor 119 calculating the electrical output of the operation of a synchronous motor, taking into account the electrical input, for each of the different static magnetic fields.

[0049] In block 505, method 500 includes the processor 119 selecting a static magnetic field that yields an electrical output of operation of the synchronous motor 101 that is closest to a measured value of the operation of the synchronous motor 101.

[0050] In block 507, method 500 includes the processor 119 selecting a sequence of points that determine the relative positions of the stator 103 and rotor 105 of the synchronous motor 101 based on a selected static magnetic field.

[0051] In addition to or instead of this, in some embodiments, different parameters of the real-space basis functions, namely the continuity of points and the corresponding surface charge density, can be determined offline in advance and stored in memory 117. During online operation, the processor 119 retrieves the different parameters of the real-space basis functions from memory 117 and determines different static magnetic fields based on the retrieved parameters.

[0052] Figure 6 shows a block diagram of a method 600 for determining the continuity of points according to one embodiment of the present disclosure, in which different parameters of the real-space basis functions are determined offline in advance.

[0053] In block 601, method 600 includes offline determination of different parameters of the real-space basis function, namely the continuity of points and the corresponding surface charge density. In block 603, method 600 includes storing the determined different parameters of the real-space basis function in memory 117.

[0054] In block 605, method 600 includes the processor 119 retrieving different parameters of real-space basis functions from memory 117 while online operation is in progress. Furthermore, in block 607, method 600 includes the processor 119 determining different static magnetic fields based on the retrieved parameters.

[0055] In block 609, method 600 includes the processor 119 calculating the electrical output of the operation of the synchronous motor 101, taking into account the electrical input, for each of the different static magnetic fields. In block 611, method 600 includes the processor 119 selecting a static magnetic field that yields the electrical output of the operation of the synchronous motor 101 that is closest to the measured value of the operation of the synchronous motor 101. In block 613, method 600 includes the processor 119 selecting a sequence of points from the selected static magnetic field that determine the relative positions of the stator 103 and the rotor 105.

[0056] Furthermore, in some embodiments, the processor 119 determines a fault based on a sequence of selected points. Specifically, it determines the type and severity of the fault based on the parameters of the real-space basis function of the selected static magnetic field. For example, different types and severities of faults associated with different parameters of the real-space basis function are stored in the memory 117. In addition, in some embodiments, control commands corresponding to each type and severity of fault are stored in the memory 117.

[0057] Figure 7 shows a tabular column 700 of an example of data stored in memory 117 according to one embodiment of the present disclosure. Different parameters 701, such as parameter 1 to parameter N, and corresponding failure types 703, failure severity 705, and control commands 707 are stored in memory 117. If the parameter of the selected real-space basis function of the static magnetic field corresponds to parameter 1 709, the processor 119 selects from memory 117 a bearing failure 711 as the failure type and high 713 as the failure severity. Furthermore, the processor 119 selects the "stop" 715 control command. The processor executes the "stop" 715 control command to stop the synchronous motor 101 in order to protect the synchronous motor 101 from failure. In another example, if the parameter of the selected real-space basis function of the static magnetic field corresponds to parameter 2 717, the processor 119 selects from memory 117 a static eccentric failure 719 as the failure type and medium 721 as the failure severity. Furthermore, the processor 119 selects a control command 723 for decelerating the synchronous motor 101. The processor executes the control command 723 for decelerating the synchronous motor 101 to decelerate it. In addition, in some implementations, the control command also includes changing the load and / or input of the synchronous motor 101.

[0058] In some embodiments, the type and severity of a fault may also be referred to as a fault indicator. The processor 119 transmits either or a combination of the fault indicator and a selected control command. In addition to or instead of this, in some embodiments, a classifier may be used to classify the type and severity of a fault based on the relative position of the stator 103 and the rotor 105.

[0059] Figure 8 shows a schematic diagram of a classifier 801 for classifying the type and severity of a failure according to one embodiment of the present disclosure. In one embodiment, the classifier 801 may be a neural network-based classifier. For example, the classifier 801 corresponds to an artificial neural network, such as a convolutional neural network, a recurrent neural network, or a feedforward neural network, which is trained to classify the type and severity of a failure based on the relative positions of the stator 103 and the rotor 105. The classifier 801 is used by the processor 119 to classify the type and severity of a failure based on the relative positions of the stator 103 and the rotor 105.

[0060] Some embodiments are based on the understanding that the surface charge density λ is necessary to solve for static magnetic fields. According to one embodiment, the surface charge density λ can be determined and the static magnetic field solved by formulating an H-solver. The formulation of the H-solver is explained mathematically below.

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[0065] Based on the relationship between the surface charge density λ(s) and H given by (6), the H solver is introduced.

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[0070] A B solver is introduced based on the relationship between the surface current density K(s) and B given by (9).

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[0082] Figure 13A shows a schematic diagram illustrating the geometric shape of a rotor according to an embodiment of the present disclosure. The rotor is defined by an outer circle 1301 with a radius r rotor = 0.6 cm and an inner ellipse 1303 with a major axis of 0.7r rotor and a minor axis of 0.3r rotor . These values are randomly selected. The dashed circle 1305 is the surface for torque calculation using Equation (16).

[0083] Figure 13B shows a graph 1307 of torque as a function of the electrical angle θ ele . The results using the direct Lorentz force law (Equation (14)) and the stress tensor (Equation (16)) are in good agreement. Equation (16) requires the B-field at the dashed circle 1305, and the B-field obtained from the surface current density and the surface charge density is substantially equal.

[0084] Figure 14 shows a block diagram of a method 1400 for detecting operational failures of a synchronous motor according to one embodiment of the present disclosure. In block 1401, the method 1400 includes collecting electrical inputs for controlling the operation of a synchronous motor and measurements of the operation of the synchronous motor caused by the electrical inputs.

[0085] In block 1403, method 1400 involves determining a continuum of points that define the relative positions of the stator and rotor of a synchronous motor, which yield a static magnetic field obtained as a weighted sum over real-space basis functions, the real-space basis functions being parameterized by pairs of adjacent points in the determined continuum of points and weighted by the surface charge density between the corresponding adjacent points, and the resulting static magnetic field describing a measure of the operation of the synchronous motor considering the electrical input.

[0086] In block 1405, method 1400 includes determining a malfunction of the synchronous motor based on the relative positions of the stator and rotor of the synchronous motor. Furthermore, in block 1407, method 1400 includes transmitting an indication of a malfunction of the synchronous motor.

[0087] Figure 15 is a schematic diagram showing a computing device 1500 for implementing the method and system of the present disclosure. The computing device 1500 includes a power supply 1501, a processor 1503, a memory 1505, and a storage device 1507, all connected to a bus 1509. Furthermore, a high-speed interface 1511, a low-speed interface 1513, a high-speed expansion port 1515, and a low-speed expansion port 1517 can be connected to the bus 1509. In addition, a low-speed connection port 1519 is connected to the bus 1509. Furthermore, an input interface 1521 can be connected to an external receiver 1523 and an output interface 1525 via the bus 1509. A receiver 1527 can be connected to an external transmitter 1529 and a transmitter 1531 via the bus 1509. Also, an external memory 1533, an external sensor 1535, a machine 1537, and an environment 1539 can be connected to the bus 1509. Furthermore, one or more external input / output devices 1541 can be connected to the bus 1509. The network interface controller (NIC) 1543 can be adapted to connect to the network 1545 via the bus 1509, and in particular, data or other data can be rendered on a third-party display device, a third-party imaging device, and / or a third-party printing device located outside the computer device 1500.

[0088] Memory 1505 can store instructions that the computer device 1500 can execute, as well as any data available to the methods and systems of this disclosure. Memory 1505 may include random access memory (RAM), read-only memory (ROM), flash memory, or any other suitable memory system. Memory 1505 may consist of one or more volatile memory units and / or one or more non-volatile memory units. Memory 1505 may also consist of another form of computer-readable medium, such as a magnetic disk or an optical disk.

[0089] The storage device 1507 can be adapted to store supplemental data and / or software modules used by the computer device 1500. The storage device 1507 may include a hard drive, optical drive, thumb drive, array of drives, or any combination thereof. Furthermore, the storage device 1507 may include computer-readable media such as a floppy disk device, hard disk device, optical disk device, or tape device, flash memory or other similar solid-state memory device, or an array of devices including a storage area network or other configuration. Instructions can be stored in an information carrier. When an instruction is executed by one or more processing devices (e.g., processor 1503), it performs one or more of the methods described above.

[0090] The computing device 1500 may optionally be linked via bus 1509 to a display interface or user interface (HMI) 1547 adapted to connect the computing device 1500 to a display device 1549 and a keyboard 1551, the display device 1549 may include, among other things, a computer monitor, a camera, a television, a projector, or a mobile device. In some implementations, the computer device 1500 may also include a printer interface for connecting to a printing device, the printing device may include, among other things, a liquid inkjet printer, a solid ink printer, a large-scale commercial printer, a thermal printer, a UV printer, or a dye-sublimation printer.

[0091] The high-speed interface 1511 manages the bandwidth-intensive operation of the computing device 1500, and the low-speed interface 1513 manages the low-bandwidth-intensive operation. Such function assignments are merely examples. In some implementations, the high-speed interface 1511 can be coupled to memory 1505, user interface (HMI) 1547, keyboard 1551, and display 1549 (e.g., through a graphics processor or accelerator), and can also be coupled to a high-speed expansion port 1515 that can accept various expansion cards via bus 1509. In some implementations, the low-speed interface 1513 is coupled to storage device 1507 and low-speed expansion port 1517 via bus 1509. The low-speed expansion port 1517, which may include various communication ports (e.g., USB, Bluetooth®, Ethernet®, Wireless Ethernet®), may be coupled to one or more input / output devices 1541. The computing device 1500 may be connected to server 1553 and rack server 1555. The computing device 1500 may be implemented in several different forms. For example, the computing device 1500 may be implemented as part of the rack server 1555.

[0092] The following description provides only specific embodiments and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the following description of specific embodiments will provide a description that enables the implementation of one or more specific embodiments for those skilled in the art. Various modifications are intended to be made to the function and configuration of the elements without departing from the spirit and scope of the subject matter disclosed in the appended claims.

[0093] Specific details are provided in the above description to ensure a full understanding of the embodiments. However, those skilled in the art will understand that the embodiments can be carried out even without these specific details. For example, systems, processes, and other elements in the disclosed subject matter may be shown as components in the form of block diagrams to avoid obscuring the embodiments with unnecessary details. In other examples, well-known processes, structures, and techniques may be shown without unnecessary details to avoid obscuring the embodiments. Furthermore, similar reference numbers and names in different drawings refer to similar elements.

[0094] Furthermore, individual embodiments may be described as processes shown as flowcharts, flow diagrams, data flow diagrams, structural diagrams, or block diagrams. While flowcharts may describe operations as sequential processes, many operations can be performed in parallel or simultaneously. In addition, the order of operations may be rearranged. A process may terminate when its operations are complete, but it may have additional steps that are not discussed or included in the diagrams. Moreover, not all operations in any process specifically described can occur in all embodiments. A process may correspond to a method, function, procedure, subroutine, subprogram, etc. If a process corresponds to a function, the termination of the function may correspond to returning the function to a calling function or main function.

[0095] Furthermore, embodiments of the disclosed subject matter may be implemented either manually or automatically, at least in part. Manual or automatic implementation may be performed, or at least assisted, through a machine, hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. If implemented in software, firmware, middleware, or microcode, the program code or code segments for performing the required tasks may be stored in a machine-readable medium. A processor(s) may perform the required tasks.

[0096] The various methods or processes outlined herein may be encoded as software executable on one or more processors employing any one of a variety of operating systems or platforms. In addition, such software may be written using any of several suitable programming languages ​​and / or programming or scripting tools, and may be compiled as executable machine language code or intermediate code that runs on a framework or virtual machine. Typically, the functions of program modules may be combined or distributed as desired in various embodiments.

[0097] Embodiments of this disclosure may be implemented as methods, and an example thereof is provided. The order of operations performed as part of this method may be determined in any suitable manner. Thus, embodiments may be configured such that operations are performed in an order different from the order illustrated, which may include performing some operations simultaneously, although they are shown as a series of operations in the illustrated embodiments.

[0098] While this disclosure has been described with reference to certain preferred embodiments, it should be understood that various other modifications and alterations are possible within the spirit and scope of this disclosure. Therefore, it is an aspect of the appended claims to cover all such variations and alterations that fall within the true spirit and scope of this disclosure.

Claims

1. A fault detector for detecting operational failures of a synchronous motor including a stator and rotor separated by an air gap, wherein the fault detector comprises a processor and a memory storing instructions, and when an instruction is executed by the processor, it is sent to the fault detector, Collecting electrical inputs for controlling the operation of the synchronous motor and measurements associated with the operation of the synchronous motor caused by the electrical inputs, via a communication channel including one or a combination of a wired communication link and / or a wireless communication link, The task is to determine the continuity of points. The sequence of the aforementioned points is A continuity of first points that define the interface between the rotor and the air gap, This includes a continuity of second points that define the interface between the stator and the air gap, The relative positions of the stator and rotor of the synchronous motor are determined by the sequence of the first points and the sequence of the second points. A static magnetic field is formed by the electrical input and the relative positions. If we define a real-space basis function as a set of parameters consisting of pairs of adjacent points in a continuous sequence, weighted by the surface charge density between each adjacent point, then the static magnetic field can be obtained as the weighted sum across the real-space basis functions. The measured value changes in response to the static magnetic field. The aforementioned instruction further commands the fault detector, For different relative positions of the stator and the rotor, different static magnetic fields are determined using the real-space basis functions, For each of the different static magnetic fields mentioned above, the electrical output of the synchronous motor operation is calculated, taking into account the electrical input. Selecting a static magnetic field that produces the electrical output of the synchronous motor closest to the measured value of the operation of the synchronous motor, Selecting a series of points from the selected static magnetic field that determine the relative positions of the stator and rotor of the synchronous motor, Based on the relative positions of the stator and rotor of the selected synchronous motor, a malfunction in the operation of the synchronous motor is determined, A fault detector that, via the communication channel, causes to transmit either or a combination of an indication of a malfunction in the operation of the synchronous motor and a control command selected based on the malfunction.

2. The processor further, The system is configured to determine different static magnetic fields based on different relative positions of the stator and the rotor by calculating a weighted sum over the real-space basis functions for each relative position. The fault detector according to claim 1, wherein the real-space basis function is parameterized by a continuity of points representing the interface between different materials inside the synchronous motor, and is weighted by a surface charge density obtained by iteratively matching boundary conditions for the interface imposed by Maxwell's equations.

3. The processor further, The system is configured to retrieve different parameters of the real-space basis functions stored in the memory, and to determine different static magnetic fields based on the retrieved parameters. The fault detector according to claim 1, wherein the different parameters include a sequence of different points and a surface charge density determined for different relative positions of the stator and rotor of the synchronous motor.

4. The fault detector according to claim 3, wherein the electrical output of the operation of the synchronous motor includes torque, and the processor is further configured to calculate the torque based on the law of Lorentz forces and an external magnetic field.

5. The fault detector according to claim 3, wherein different types and severities of faults related to the different parameters of the real-space basis function are stored in the memory, and the processor is further configured to select from the memory, a fault type and severity, a control command, or both, based on the parameters of the selected real-space basis function of the static magnetic field.

6. The fault detector according to claim 5, wherein the processor is further configured to control the synchronous motor based on the control command.

7. The fault detector according to claim 1, wherein the fault indication includes the type and severity of the fault, and the processor is further configured to run a classifier trained to classify the type and severity of the fault based on the relative positions of the stator and the rotor.

8. The fault detector according to claim 1, wherein the processor is configured to further calculate the magnetic field strength based on an initial value of the surface charge density and to iteratively update the surface charge density based on the relationship between the surface charge density and the magnetic field strength until a termination condition is met.

9. The fault detector according to claim 1, wherein the processor is configured to further calculate the magnetic flux density based on an initial value of the surface current density and to iteratively update the surface current density based on the relationship between the surface current density and the magnetic flux density until a termination condition is met.

10. The aforementioned processor further, Initial values ​​are assigned to the surface charge density and surface current density. Based on the initial value of the surface charge density, the magnetic field strength is calculated. The surface current density is updated based on the magnetic field strength, Based on the updated surface current density, calculate the magnetic flux density. The fault detector according to claim 1, configured to update the surface charge density based on the magnetic flux density.

11. The fault detector according to claim 1, wherein the electrical input includes one or a combination of the current and / or voltage of each winding of the synchronous motor, and the measured value includes one or a combination of the output torque and / or the mutual inductance between different windings.

12. The fault detector according to claim 1, wherein the fault determined in the operation of the synchronous motor includes either a bearing failure or an eccentric failure, or a combination thereof.

13. A method for detecting operational failures of a synchronous motor including a stator and rotor separated by an air gap, wherein the method is: Collecting electrical inputs for controlling the operation of the synchronous motor and measurements of the operation of the synchronous motor caused by the electrical inputs, via a communication channel including one or a combination of a wired communication link and / or a wireless communication link, This includes determining the continuity of points, The sequence of the aforementioned points is A continuity of first points that define the interface between the rotor and the air gap, This includes a continuity of second points that define the interface between the stator and the air gap, The relative positions of the stator and rotor of the synchronous motor are determined by the sequence of the first points and the sequence of the second points. A static magnetic field is formed by the electrical input and the relative positions. If we define a real-space basis function as a set of parameters consisting of pairs of adjacent points in a continuous sequence, weighted by the surface charge density between each adjacent point, then the static magnetic field can be obtained as the weighted sum across the real-space basis functions. The measured value changes in response to the static magnetic field. The above method further, For different relative positions of the stator and the rotor, different static magnetic fields are determined using the real-space basis functions, For each of the different static magnetic fields mentioned above, the electrical output of the synchronous motor operation is calculated, taking into account the electrical input. Selecting a static magnetic field that produces the electrical output of the synchronous motor closest to the measured value of the operation of the synchronous motor, Selecting a series of points from the selected static magnetic field that determine the relative positions of the stator and rotor of the synchronous motor, Based on the relative positions of the stator and rotor of the selected synchronous motor, a malfunction in the operation of the synchronous motor is determined, A method comprising transmitting, via the communication channel, one or a combination of an indication of a malfunction in the operation of the synchronous motor and a control command selected based on the malfunction.

14. The method further, This includes determining different static magnetic fields based on different relative positions of the stator and the rotor by calculating a weighted sum over the real-space basis functions for each relative position, The method according to claim 13, wherein the real-space basis function is parameterized by a continuity of points representing the interface between different materials inside the synchronous motor, and is weighted by a surface charge density obtained by iteratively matching boundary conditions for the interface imposed by Maxwell's equations.

15. The above method further, Retrieving different parameters of the real-space basis function stored in memory, This includes determining different static magnetic fields based on the extracted parameters, The method according to claim 13, wherein the different parameters include a continuity of different points and a surface charge density determined for different relative positions of the stator and rotor of the synchronous motor.

16. The method according to claim 15, wherein different types and severities of failures related to the different parameters of the real-space basis function are stored in the memory, and the method further comprises selecting a type and severity of failure, a control command, or both from the memory based on the parameters of the selected real-space basis function of the static magnetic field.

17. The method according to claim 16, further comprising controlling the synchronous motor based on the control command.

18. The method according to claim 13, wherein the indication of the fault includes the type and severity of the fault, and the method further includes running a classifier trained to classify the type and severity of the fault based on the relative positions of the stator and the rotor.

19. The method according to claim 13, wherein the electrical input includes one or a combination of the current and / or voltage of each winding of the synchronous motor, and the measured values ​​include one or a combination of the output torque and / or the mutual inductance between different windings.

20. A non-temporary computer-readable storage medium containing a processor-executable program for performing a method for detecting operational failures of a synchronous motor including a stator and rotor separated by an air gap, wherein the method is: Collecting electrical inputs for controlling the operation of the synchronous motor and measurements of the operation of the synchronous motor caused by the electrical inputs, via a communication channel including one or a combination of a wired communication link and / or a wireless communication link, This includes determining the continuity of points, The sequence of the aforementioned points is A continuity of first points that define the interface between the rotor and the air gap, This includes a continuity of second points that define the interface between the stator and the air gap, The relative positions of the stator and rotor of the synchronous motor are determined by the sequence of the first points and the sequence of the second points. A static magnetic field is formed by the electrical input and the relative positions. If we define a real-space basis function as a set of parameters consisting of pairs of adjacent points in a continuous sequence, weighted by the surface charge density between each adjacent point, then the static magnetic field can be obtained as the weighted sum across the real-space basis functions. The measured value changes in response to the static magnetic field. The above method further, For different relative positions of the stator and the rotor, different static magnetic fields are determined using the real-space basis functions, For each of the different static magnetic fields mentioned above, the electrical output of the synchronous motor operation is calculated, taking into account the electrical input. Selecting a static magnetic field that produces the electrical output of the synchronous motor closest to the measured value of the operation of the synchronous motor, Selecting a series of points from the selected static magnetic field that determine the relative positions of the stator and rotor of the synchronous motor, Based on the relative positions of the stator and rotor of the selected synchronous motor, a malfunction in the operation of the synchronous motor is determined, A non-temporary computer-readable storage medium that includes transmitting, via the communication channel, one or a combination of an indication of a malfunction in the operation of the synchronous motor and a control command selected based on the malfunction.

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