Electric drive fault diagnosis method, electric drive system and new energy vehicle

Abstract

The invention provides an electric drive fault diagnosis method, an electric drive system and a new energy vehicle. The electric drive fault diagnosis method comprises the following steps: acquiring a vibration signal acquired by a vibration sensor arranged on an electric drive integrated shell; converting the vibration signal into an N-order fault index quantity, and comparing the N-order fault index quantity with a preset index quantity threshold table; and if the number of times that the N-order fault index quantity exceeds the index quantity threshold table reaches a number-of-times limit value within a preset duration, determining that the electric drive has a fault, and sending a fault signal to the outside. According to the configuration, the vibration signal can be converted into the N-order fault index quantity, so that the N-order fault index quantity is compared with the index quantity threshold table to detect the early mechanical fault of the electric drive. Furthermore, when the number of times that the N-order fault index quantity exceeds reaches a number-of-times limit value, it is determined that the electric drive has a fault, and a fault signal is sent out, so that non-fault vibration signals introduced by road conditions or working conditions can be effectively filtered out, and the reliability and practicability of fault diagnosis are improved.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a fault diagnosis method for electric drive, an electric drive system, and a new energy vehicle. Background Technology

[0002] Currently, electric drive systems in new energy vehicles lack reliable solutions for proactively detecting early mechanical failures. Mechanical failures typically only become apparent when the fault becomes severe enough to affect power output. This often leads to the escalation of the fault and damage to other components. Summary of the Invention

[0003] The purpose of this invention is to provide a fault diagnosis method for electric drives, an electric drive system, and a new energy vehicle, so as to solve the problem that existing electric drive systems lack detection of early mechanical failures.

[0004] To solve the above-mentioned technical problems, the present invention provides a fault diagnosis method for electric drives, comprising: The vibration signal is acquired by the vibration sensor installed on the integrated housing of the electric drive. The vibration signal is converted into an Nth-order fault index and compared with a preset index threshold table. If the number of times the N-order fault index exceeds the threshold table within a preset time period reaches the limit, then it is determined that the electric drive has a fault, and a fault signal is sent to the outside.

[0005] Optionally, the step of converting the vibration signal into an Nth-order fault index includes: Based on the vibration signal, characteristic parameters characterizing the operating state of the electric drive are calculated; The characteristic parameters are subjected to Fourier transform based on the motor speed to obtain N fault index quantities of different orders.

[0006] Optionally, the characteristic parameters are calculated based on the vibration signal and the motor speed within a time period.

[0007] Optionally, the feature parameters include kurtosis or peak factor.

[0008] Optionally, the index threshold table is pre-calibrated based on the electric drive.

[0009] Optionally, the fault diagnosis method of the electric drive is repeated periodically, with a cycle of 0.01s to 3600s.

[0010] Optionally, the fault diagnosis method for the electric drive further includes: Based on the correspondence between the fault index quantities of each order in the N-order fault index quantities and the mechanical characteristics of the electric drive, the location of the fault is determined.

[0011] Optionally, the step of converting the vibration signal into an Nth-order fault index and comparing it with a preset index threshold table includes: The fault indexes of each order in the N-order fault indexes are compared with the corresponding thresholds in the index threshold table; if the fault index of any order exceeds the corresponding threshold, it is determined that the N-order fault index exceeds the index threshold table.

[0012] To address the aforementioned technical problems, the present invention also provides an electric drive system, comprising: an electric drive, a vibration sensor, and a fault detection module; the electric drive includes at least a motor, a motor controller, and a reducer; wherein the motor, the controller, and the reducer have an integrated housing; the vibration sensor is disposed in the integrated housing and is communicatively connected to the fault detection module; the fault detection module is configured to diagnose faults in the electric drive according to the fault diagnosis method for the electric drive described above.

[0013] To address the aforementioned technical problems, the present invention also provides a new energy vehicle, which includes the electric drive system described above.

[0014] In summary, in the electric drive fault diagnosis method, electric drive system, and new energy vehicle provided by the present invention, the electric drive fault diagnosis method includes: acquiring vibration signals collected by vibration sensors deployed on the integrated housing of the electric drive; converting the vibration signals into an N-order fault index quantity and comparing them with a preset index quantity threshold table; if the N-order fault index quantity exceeds the index quantity threshold table a certain number of times within a preset time period, then it is determined that the electric drive has a fault, and a fault signal is sent to the outside.

[0015] With this configuration, vibration signals collected by vibration sensors integrated into the housing can be converted into Nth-order fault indicators. These indicators can then be compared with a threshold table to detect early mechanical faults in the electric drive. Furthermore, by counting the number of times the Nth-order fault indicator is exceeded, a fault is confirmed in the electric drive and a fault signal is issued only when the limit is reached. This effectively filters out non-fault vibration signals introduced by road or operating conditions, improving the reliability and practicality of fault diagnosis. Attached Figure Description

[0016] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention.

[0017] Figure 1 This is a flowchart of a fault diagnosis method for an electric drive according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the electric drive system according to an embodiment of the present invention.

[0019] In the attached diagram: 1-Electric drive; 10-Integrated housing; 11-Motor; 12-Motor controller; 13-Reducer; 2-Vibration sensor; 3-Fault detection module. Detailed Implementation

[0020] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0021] As used in this invention, the singular forms “a,” “an,” “one,” and “the” include plural objects; the term “or” is generally used to mean “and / or”; the term “a number” is generally used to mean “at least one”; and the term “at least two” is generally used to mean “two or more”. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature; “one end” and “the other end,” and “proximal end” and “distal end” generally refer to two corresponding parts, which include not only endpoints. Furthermore, the terms "installed," "connected," and "attached," as used in this invention, and the term "set" on one element from another, should be interpreted broadly. They generally only indicate a connection, coupling, cooperation, or transmission relationship between the two elements, which can be direct or indirect through an intermediate element. They should not be construed as indicating or implying a spatial relationship between the two elements, meaning one element can be located inside, outside, above, below, or to one side of another element, unless otherwise explicitly stated. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Additionally, directional terms such as above, below, up, down, upward, downward, left, and right are used relative to exemplary embodiments as shown in the figures, with upward or upper directions pointing towards the top of the corresponding figure, and downward or lower directions pointing towards the bottom of the corresponding figure.

[0022] The purpose of this invention is to provide a fault diagnosis method for electric drives, an electric drive system, and a new energy vehicle, to solve the problem that existing electric drive systems lack the ability to detect early mechanical failures. The following description refers to the accompanying drawings.

[0023] Please refer to Figure 1 and Figure 2 This invention provides a method for diagnosing faults in an electric drive, comprising: Step S1: Obtain the vibration signal collected by the vibration sensor 2 installed on the integrated housing 10 of the electric drive 1; Step S2: Convert the vibration signal into an Nth-order fault index and compare it with a preset index threshold table; Step S3: If the number of times the N-order fault index exceeds the index threshold table reaches the limit within a preset time period, it is determined that the electric drive 1 has a fault and a fault signal is sent to the outside.

[0024] Please refer to Figure 2 This embodiment also provides an electric drive system, which includes: an electric drive 1, a vibration sensor 2, and a fault detection module 3; the electric drive 1 includes at least a motor 11, a motor controller 12, and a reducer 13; wherein the motor 11, the controller 12, and the reducer 13 have an integrated housing 10; the vibration sensor 2 is disposed in the integrated housing 10, and the vibration sensor 2 is communicatively connected to the fault detection module 3; the fault detection module 3 is configured to perform fault diagnosis on the electric drive 1 according to the fault diagnosis method of the electric drive provided in this embodiment.

[0025] In an alternative example, the electric drive 1 provided in this embodiment is a three-in-one electric drive, that is, it integrates a motor 11, a motor controller 12, and a reducer 13, all three being housed in an integrated housing 10. It should be noted that the integrated housing 10 can be a single-piece molded housing or a composite housing composed of several sub-housings. The various regions of the integrated housing 10 corresponding to the motor 11, motor controller 12, and reducer 13 are physically connected or integrally molded, thus allowing vibrations between these regions to be transmitted. Vibration sensors 2 are disposed on the portions of the integrated housing 10 corresponding to any one of the motor 11, motor controller 12, and reducer 13, and can collect vibration signals from either the motor 11 or the reducer 13.

[0026] Furthermore, the vibration signal collected by the vibration sensor 2 can be transmitted to the fault detection module 3. The fault detection module 3 can convert the vibration signal into an N-order fault index quantity and compare it with a preset index quantity threshold table. If the N-order fault index quantity exceeds the limit of the index quantity threshold table within a preset time period, it is determined that the electric drive 1 has a fault and sends a fault signal to the outside, such as sending a fault signal to the host computer system, or providing a prompt through warning lights, buzzers, display screens, or other commonly used prompting methods in the field.

[0027] Due to factors such as road conditions and operating conditions in reality, some unwanted vibration signals may be introduced. These unwanted vibration signals may be superimposed on the vibration signal collected by vibration sensor 2, which may cause the fault detection module 3 to misjudge the fault. In order to filter out the influence of these unwanted vibration signals, this embodiment counts the number of times the N-order fault index exceeds the index threshold table within a preset time period. The purpose of counting is to avoid non-fault vibration signals introduced by road conditions or operating conditions. Only when the count reaches (equal to or greater than) the limit value within a predetermined time (such as several minutes) will it be determined that the electric drive 1 has a fault and a fault signal will be issued. This can effectively filter out non-fault vibration signals introduced by road conditions or operating conditions, improving the reliability and practicality of fault diagnosis.

[0028] Furthermore, in step S3, if the number of times the N-order fault index exceeds the index threshold table within the preset time period does not reach (means less than) the limit, or in other words, the N-order fault index does not exceed the index threshold table, then it is determined that the electric drive 1 does not have a fault. Preferably, the count in the current preset time period is reset to zero. When fault detection is repeated again within the preset time period of the next cycle, the count is reset.

[0029] It should be noted that the electric drive 1 referred to in this embodiment is not limited to being a three-in-one electric drive; it can also be a multi-functional electric drive, and this embodiment is not limited to this. For example, the electric drive 1 may also include at least one of a charger, DC-DC converter, VCU, BMS, TMS, and PDU.

[0030] The fault diagnosis method for electric drives provided in this embodiment will be further explained below.

[0031] In an optional example, step S2, which converts the vibration signal into an Nth-order fault index, includes: Step S21: Calculate the characteristic parameters representing the operating state of the electric drive 1 based on the vibration signal; Step S22: Perform Fourier transform on the characteristic parameters based on the motor speed to obtain N fault index quantities of different orders.

[0032] Optionally, the feature parameters here are calculated based on the vibration signal and the motor speed within a certain time period. These feature parameters, such as kurtosis or maxima, can be used to characterize the operating state of the electric drive 1. In one example, the fault detection module 3 can read vibration signals over several time periods and the motor speed 11 within those time periods, and calculate the feature parameters using a statistical algorithm. Then, by performing a Fourier transform on the feature parameters based on the motor speed 11, N fault index quantities of different orders can be obtained. The specific statistical algorithms and the principles of the Fourier transform can be found in existing technologies, and will not be elaborated upon in this invention.

[0033] Furthermore, the fault diagnosis method for the electric drive also includes: Step S4: Determine the location of the fault based on the correspondence between the fault index quantities of each order in the N-order fault index quantities and the mechanical characteristics of the electric drive.

[0034] Step S4 can be performed before step S3. Research has found a certain correspondence between the fault index quantities of different orders of characteristic parameters and the mechanical characteristics of different parts of the electric drive 1. When a mechanical fault occurs in a specific part of the electric drive, a specific order of vibration will be generated. Therefore, based on the correspondence between the order and mechanical characteristics, the possible location of the fault can be further determined. This correspondence can be calibrated during the research and development or production stage of the electric drive. For example, in an exemplary case, when a mechanical fault occurs in the gear of the reducer 13, a certain order of vibration can be generated. At this time, it is determined that there is a correspondence between the fault index quantity of this order and the gear. If the fault index quantity of this order is relatively prominent among the N-order fault index quantities, then based on the correspondence, it can be determined that the fault location may be in the gear part of the reducer 13. Further optionally, the information of the fault location can also be used as part of the fault signal sent out in the subsequent step S3.

[0035] Optionally, the index threshold table is based on a pre-calibrated electric drive 1. For example, it can be obtained by calibrating the electric drive 1 during the product development stage. The index threshold table contains thresholds corresponding to multiple orders. Further, step S2, which compares the Nth-order fault index with the preset index threshold table, includes: Step S23: Compare the fault index quantities of each order in the N-order fault index quantities with the corresponding thresholds in the index quantity threshold table; if the fault index quantity of any order exceeds the corresponding threshold, it is determined that the N-order fault index quantity exceeds the index quantity threshold table.

[0036] In one example, the N fault index quantities of different orders obtained in step S22 can be compared with the corresponding thresholds in the index quantity threshold table. If any one of the fault index quantities exceeds the corresponding threshold, it is determined that the Nth-order fault index quantity exceeds the index quantity threshold table. At this time, a count can be performed based on step S3. Of course, in other embodiments, the method of determining whether the Nth-order fault index quantity exceeds the index quantity threshold table is not limited to the method in step S23. For example, it can also be determined that the Nth-order fault index quantity exceeds the index quantity threshold table only when the fault index quantities of some orders among the Nth-order fault index quantities exceed the corresponding thresholds. The specific settings can be set according to the actual situation, and this embodiment is not limited to this.

[0037] The electric drive fault diagnosis method provided in this embodiment is preferably executed periodically, with a repetition period selectable from 0.01s to 3600s. Optionally, in some embodiments, the electric drive fault diagnosis method provided in this embodiment can be configured as an executable program, which can be written, for example, into the fault detection module 3. Further, the fault detection module 3 can be an independent module or a virtual program module integrated into the vehicle control system of a new energy vehicle; the present invention is not limited to this.

[0038] Based on the electric drive fault diagnosis method and electric drive system described above, this embodiment of the invention also provides a new energy vehicle, which includes the electric drive system described above. This new energy vehicle can be a pure electric vehicle or a hybrid vehicle; this embodiment is not limited to either. The structure and principle of other components of this new energy vehicle can be found in the prior art, and will not be elaborated upon in this embodiment.

[0039] In summary, the electric drive fault diagnosis method, electric drive system, and new energy vehicle provided by this invention include: acquiring vibration signals collected by vibration sensors installed on the integrated housing of the electric drive; converting the vibration signals into an Nth-order fault index quantity and comparing it with a preset index quantity threshold table; if the number of times the Nth-order fault index quantity exceeds the index quantity threshold table reaches a certain limit within a preset time period, it is determined that the electric drive has a fault, and a fault signal is issued externally. With this configuration, the vibration signals collected by the vibration sensors installed on the integrated housing can be converted into an Nth-order fault index quantity, which can then be compared with the index quantity threshold table to detect early mechanical faults in the electric drive. Furthermore, by counting the number of times the Nth-order fault index quantity exceeds the limit, and only when the limit is reached is it determined that the electric drive has a fault and a fault signal is issued externally, non-fault vibration signals introduced by road conditions or operating conditions can be effectively filtered out, improving the reliability and practicality of fault diagnosis.

[0040] It should be noted that the above embodiments can be combined with each other. The above description is only a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. A fault diagnosis method for an electric drive, characterized in that, include: The vibration signal is acquired by the vibration sensor installed on the integrated housing of the electric drive. The vibration signal is converted into an Nth-order fault index and compared with a preset index threshold table. If the number of times the N-order fault index exceeds the threshold table within a preset time period reaches the limit, then it is determined that the electric drive has a fault, and a fault signal is sent to the outside.

2. The fault diagnosis method for electric drives according to claim 1, characterized in that, The steps for converting the vibration signal into an Nth-order fault index include: Based on the vibration signal, characteristic parameters characterizing the operating state of the electric drive are calculated; The characteristic parameters are subjected to Fourier transform based on the motor speed to obtain N fault index quantities of different orders.

3. The fault diagnosis method for electric drives according to claim 2, characterized in that, The characteristic parameters are calculated based on the vibration signal and the motor speed within a time period.

4. The fault diagnosis method for electric drives according to claim 2, characterized in that, The characteristic parameters include kurtosis or peak factor.

5. The fault diagnosis method for electric drives according to claim 1, characterized in that, The threshold table for the index quantity is based on the pre-calibration of the electric drive.

6. The fault diagnosis method for electric drives according to claim 1, characterized in that, The fault diagnosis method for the electric drive is repeatedly executed periodically, with a cycle of 0.01s to 3600s.

7. The fault diagnosis method for electric drives according to claim 1, characterized in that, The fault diagnosis method for the electric drive also includes: Based on the correspondence between the fault index quantities of each order in the N-order fault index quantities and the mechanical characteristics of the electric drive, the location of the fault is determined.

8. The fault diagnosis method for an electric drive according to claim 1, characterized in that, The steps of converting the vibration signal into an Nth-order fault index and comparing it with a preset index threshold table include: The fault indexes of each order in the N-order fault indexes are compared with the corresponding thresholds in the index threshold table; if the fault index of any order exceeds the corresponding threshold, it is determined that the N-order fault index exceeds the index threshold table.

9. An electric drive system, characterized in that, include: An electric drive, a vibration sensor, and a fault detection module; the electric drive includes at least a motor, a motor controller, and a reducer; wherein the motor, the controller, and the reducer have an integrated housing; the vibration sensor is disposed in the integrated housing and is communicatively connected to the fault detection module; the fault detection module is configured to perform fault diagnosis on the electric drive according to any one of claims 1 to 8.

10. A new energy vehicle, characterized in that, Including the electric drive system according to claim 9.

Images