Shaft voltage testing device of electric drive system

Abstract

The invention relates to an electric drive system shaft voltage testing device, and the device comprises a housing which is provided with an inner cavity, and the interior of the housing is provided with a stator; the rotating shaft is provided with a first end and a second end in the length direction of the rotating shaft, the rotating shaft is located in an inner cavity of the stator, the first end is rotationally connected with the shell through a first bearing, and the second end extends out of the shell and is rotationally connected with the shell through a second bearing. The rotor is connected with the rotating shaft and corresponds to the stator; the first conducting ring is connected with the shell and sleeves the first end, and a carbon brush of the first conducting ring is in contact with the first end; the second conducting ring is connected with the shell and sleeves the second end, and a carbon brush of the second conducting ring is in contact with the second end; the oscilloscope is provided with a channel used for detecting voltage. According to the invention, through one-time modification, a voltage test that only the first conducting ring is arranged on the motor, a voltage test that only the second conducting ring is arranged on the motor, and a voltage test that the first conducting ring and the second conducting ring are arranged on the motor at the same time can be carried out, so that the shaft voltage solution is increased, and the period and the cost of the scheme are reduced.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and in particular to a device for testing shaft voltage in an electric drive system. Background Technology

[0002] With the rapid development of new energy vehicles towards higher voltage platforms (800V and above), higher power density, and higher frequency control, bearing electro-corrosion caused by shaft voltage in electric drive systems has become one of the core bottlenecks restricting the reliability of drive motors. Shaft voltage in electric drive systems mainly originates from the high-frequency pulse width modulation (PWM) control characteristics of the electric drive system's electronic control and the coupling effect of parasitic capacitance within the motor. When the electronic control uses PWM, the output common-mode voltage contains rapidly changing dv / dt components. This high-frequency voltage forms a closed loop through paths such as the parasitic capacitance between the stator windings and rotor, and the oil film capacitance between the inner and outer rings of the bearing and the balls, thus inducing shaft voltage on the motor shaft. Studies have shown that the peak-to-peak shaft voltage of four-pole or higher permanent magnet synchronous motors can reach 20V-40V under an 800V high-voltage platform. Under frequent vehicle start-stop, high torque output, and complex operating conditions, bearing failure caused by shaft voltage increases significantly, directly affecting the durability, safety, and NVH performance of new energy vehicles.

[0003] Therefore, it is necessary to detect the shaft voltage or shaft current and compare the shaft voltage with the corresponding voltage threshold, or compare the shaft current with the corresponding current threshold, in order to detect whether there is electrical corrosion in the bearing.

[0004] However, the current process for shaft voltage testing and verification involves first determining the shaft voltage value of a prototype and then evaluating it based on the measured values. If an additional shaft voltage solution is needed, the prototype must be modified and re-verified, a process that is time-consuming and costly.

[0005] The information disclosed in the background section is only for enhancing the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] Based on this, an electric drive system shaft voltage testing device is provided. This application is equipped with a first conductive ring and a second conductive ring, which can add a testing solution for shaft voltage at any time without modifying the prototype, thereby reducing the solution cycle and cost.

[0007] Therefore, in a first aspect, embodiments of this application provide a shaft voltage testing device for an electric drive system, comprising: The housing has an inner cavity, and a stator is disposed inside the housing; A rotating shaft has a first end and a second end along its length. The rotating shaft is located in the inner cavity of the stator. The first end is rotatably connected to the housing through a first bearing, and the second end extends out of the housing and is rotatably connected to the housing through a second bearing. The rotor is connected to the rotating shaft and corresponds to the stator; A first conductive ring is connected to the housing and sleeved on the first end, and the carbon brush of the first conductive ring is in contact with the first end; The second conductive ring is connected to the housing and sleeved on the second end, and the carbon brush of the second conductive ring is in contact with the second end; An oscilloscope has a channel for detecting voltage.

[0008] In one embodiment, the oscilloscope is provided with: The positive terminal of the first channel is used to connect to the first conductive ring, and the negative terminal of the first channel is used to connect to the first bearing, so as to test the voltage at the tail end of the motor. The positive terminal of the second channel is used to connect to the second conductive ring, and the negative terminal of the second channel is used to connect to the second bearing, so as to test the voltage at the output shaft end of the motor. The positive terminal of the third channel is used to connect to the first conductive ring, and the negative terminal of the third channel is used to connect to the second conductive ring, for testing the voltage between the motor tail end and the output shaft end.

[0009] In one embodiment, the end of the housing near the first end of the rotating shaft is disconnected from the first conductive ring, and the end of the housing near the second end of the rotating shaft is disconnected from the second conductive ring.

[0010] In one embodiment, the end of the housing near the first end of the rotating shaft is connected to the first conductive ring, and the end of the housing near the second end of the rotating shaft is disconnected from the second conductive ring.

[0011] In one embodiment, the end of the housing near the first end of the rotating shaft is disconnected from the first conductive ring, and the end of the housing near the second end of the rotating shaft is connected to the second conductive ring.

[0012] In one embodiment, the end of the housing near the first end of the rotating shaft is connected to the first conductive ring, and the end of the housing near the second end of the rotating shaft is connected to the second conductive ring.

[0013] In one embodiment, the first conductive ring is provided with a first test line and a first connecting line of different colors, the first test line being used to connect to the oscilloscope and the first connecting line being used to connect to the housing; the second conductive ring is provided with a second test line and a second connecting line of different colors, the second test line being used to connect to the oscilloscope and the second connecting line being used to connect to the housing.

[0014] In one embodiment, a first housing wire and a second housing wire are respectively provided at both ends of the housing. The first housing wire is used to connect to the first connecting line, and the second housing wire is used to connect to the second connecting line.

[0015] In one embodiment, the housing is provided with a first support assembly, which includes an interconnected column and an insulating base, with one end of the column opposite to the insulating base connected to the housing.

[0016] In one embodiment, an insulating turntable is provided between the second end of the rotating shaft and the testing machine interface.

[0017] The electric drive system shaft voltage testing device provided according to the embodiments of this application includes a housing, a rotating shaft, a rotor, a first conductive ring, a second conductive ring, and an oscilloscope. The housing has an inner cavity, and a stator is disposed inside the housing. The rotating shaft has a first end and a second end along its length direction. The rotating shaft is located in the inner cavity of the stator. The first end is rotatably connected to the housing through a first bearing, and the second end extends out of the housing and is rotatably connected to the housing through a second bearing. The rotor is connected to the rotating shaft and corresponds to the stator. The first conductive ring is connected to the housing and sleeved on the first end, and the carbon brush of the first conductive ring is in contact with the first end. The second conductive ring is connected to the housing and sleeved on the second end, and the carbon brush of the second conductive ring is in contact with the second end. The oscilloscope is provided with a channel for detecting voltage. This application includes a first conductive ring and a second conductive ring. With only one modification, this application allows for testing of the motor with only the voltage of the first conductive ring, the voltage of the motor with only the voltage of the second conductive ring, or the voltage of the motor with both the first and second conductive rings simultaneously. This application adds a shaft voltage solution, eliminating the need for subsequent modifications to the prototype and re-verification, thus reducing the time-consuming nature and cost of the solution. Attached Figure Description

[0018] Figure 1 This diagram shows a simplified illustration of a shaft voltage testing device for an electric drive system according to an embodiment of this application. Figure 2 This illustration shows a structural schematic diagram of a shaft voltage testing device for an electric drive system provided in an embodiment of this application; Figure 3 This illustration shows a structural schematic diagram of an insulating base provided in an embodiment of this application; Figure 4 This diagram illustrates the structure of an insulating turntable provided in an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 1. Housing; 11. First housing wire; 12. Second housing wire; 13. Insulating base; 2. Shaft; 21. First end; 211. First bearing; 2111. First bearing wire; 22. Second end; 23. Insulating turntable; 221. Second bearing; 2211. Second bearing wire; 3. Rotor; 4. First conductive ring; 41. First test lead; 42. First connecting wire; 5. Second conductive ring; 51. Second test lead; 52. Second connecting wire; 6. Stator. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0023] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "lateral," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are only for the purpose of simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] The current process for shaft voltage testing and verification involves first determining the shaft voltage value of a prototype and then evaluating it based on the measured values. If an additional shaft voltage solution is needed, the prototype must be modified and re-verified, a process that is time-consuming and costly.

[0025] Reference Figure 1 and Figure 2 , Figure 1 This diagram shows a simplified illustration of a shaft voltage testing device for an electric drive system according to an embodiment of this application. Figure 2 This diagram illustrates the structure of a shaft voltage testing device for an electric drive system provided in an embodiment of this application.

[0026] To address the aforementioned issues, this application provides a shaft voltage testing device for an electric drive system, comprising a housing 1, a rotating shaft 2, a rotor 3, a first conductive ring 4, a second conductive ring 5, and an oscilloscope. The housing 1 has an inner cavity, and a stator 6 is disposed within the housing 1. The rotating shaft 2 has a first end 21 and a second end 22 along its length direction. The rotating shaft 2 is located within the inner cavity of the stator 6. The first end 21 is rotatably connected to the housing 1 via a first bearing 211, and the second end 22 extends out of the housing 1 and is rotatably connected to the housing 1 via a second bearing 212. The rotor 3 is connected to the rotating shaft 2 and corresponds to the stator 6. The first conductive ring 4 is connected to the housing 1 and sleeved on the first end 21, with the carbon brush of the first conductive ring 4 contacting the first end 21. The second conductive ring 5 is connected to the housing 1 and sleeved on the second end 22, with the carbon brush of the second conductive ring 5 contacting the second end 22. The oscilloscope has multiple channels for detecting voltage.

[0027] It should be understood that the electric drive system shaft voltage testing device includes a housing 1, which is a motor housing 1. The housing 1 has an inner cavity, one end of which is open. A stator 6 is housed inside the housing 1, and the stator 6 also has an inner cavity. This application also includes a rotor 3, which is sleeved on the middle of the rotating shaft 2 and connected to the rotating shaft 2. When the rotating shaft 2 rotates, the rotor 3 rotates with the rotating shaft 2. The rotor 3 and the rotating shaft 2 are located in the inner cavity of the stator 6. The rotating shaft 2 has two ends along its length, namely a first end 21 and a second end 22. The first end 21 is located in the inner cavity of the housing 1 and is rotatably connected to the housing 1 through a first bearing 211. The second end 22 extends out of the inner cavity of the housing 1 and is rotatably connected to the housing 1 through a second bearing 221, thereby making the rotating shaft 2 rotatably connected to the housing 1.

[0028] The electric drive system shaft voltage testing device also includes a first conductive ring 4 and a second conductive ring 5. The first conductive ring 4 is connected to the housing 1 and sleeves the first end 21 of the rotating shaft 2. The carbon brush of the first conductive ring 4 is in contact with the first end 21 of the rotating shaft 2, that is, the first conductive ring 4 is electrically connected to the first end 21 of the rotating shaft 2. The second conductive ring 5 is connected to the housing 1 and sleeves the second end 22 of the rotating shaft 2. The carbon brush of the second conductive ring 5 is in contact with the second end 22 of the rotating shaft 2, that is, the second conductive ring 5 is electrically connected to the second end 22 of the rotating shaft 2.

[0029] This application also includes an oscilloscope for detecting shaft voltages at three points: the motor tail end, the motor output shaft end, and the motor tail end and the motor output shaft end. Compared to the currently common method of only testing the shaft voltage at the motor tail end, this method can more accurately assess the shaft voltage risk of the electric drive system, formulate shaft voltage mitigation measures, and improve the reliability of the electric drive system. This application includes a first conductive ring 4 and a second conductive ring 5. With only one modification, this application allows for testing of the motor with only the voltage of the first conductive ring 4, the voltage of the motor with only the voltage of the second conductive ring 5, or the voltage of the motor with both the first conductive ring 4 and the second conductive ring 5 simultaneously. This application adds a shaft voltage solution, eliminating the need for subsequent modification and re-verification of the prototype, thus reducing the cycle time and cost of the solution.

[0030] In some optional embodiments, the oscilloscope is provided with a first channel positive terminal, a first channel negative terminal, a second channel positive terminal, a second channel negative terminal, a third channel positive terminal, and a third channel negative terminal. The first channel positive terminal is used to connect to the first conductive ring 4, and the first channel negative terminal is used to connect to the first bearing 211, for testing the voltage at the motor tail end; the second channel positive terminal is used to connect to the second conductive ring 5, and the second channel negative terminal is used to connect to the second bearing 221, for testing the voltage at the motor output shaft end; the third channel positive terminal is used to connect to the first conductive ring 4, and the third channel negative terminal is used to connect to the second conductive ring 5, for testing the voltage between the motor tail end and the output shaft end.

[0031] This application features six test channels. During testing, the positive terminal of the first channel of an oscilloscope is connected to the first conductive ring 4, and the negative terminal is connected to the first bearing 211 to test the voltage at the motor's tail end. The positive terminal of the second channel is connected to the second conductive ring 5, and the negative terminal is connected to the second bearing 221 to test the voltage at the motor's output shaft end. The positive terminal of the third channel is connected to the first conductive ring 4, and the negative terminal is connected to the second conductive ring 5 to detect the voltage between the motor's tail end and the output shaft end. This application allows for the detection of three voltage points on the motor using a single oscilloscope, reducing testing costs compared to using three separate oscilloscopes.

[0032] In some optional embodiments, the end of the housing 1 near the first end 21 of the rotating shaft 2 is disconnected from the first conductive ring 4, and the end of the housing 1 near the second end 22 of the rotating shaft 2 is disconnected from the second conductive ring 5. In this connection method, the electric drive system is in a state without any conductive rings, and the shaft voltage at three points—the motor tail end, the motor output shaft end, and the area between the motor tail end and the output shaft end—is acquired using an oscilloscope.

[0033] In some optional embodiments, the end of the housing 1 near the first end 21 of the rotating shaft 2 is connected to the first conductive ring 4, and the end of the housing 1 near the second end 22 of the rotating shaft 2 is disconnected from the second conductive ring 5. In this connection method, the electric drive system is in a state where the first conductive ring 4 is only installed at the tail end of the motor, and the shaft voltage at three points—the tail end of the motor, the output shaft end of the motor, and the area between the tail end of the motor and the output shaft end—can be acquired using an oscilloscope.

[0034] In some optional embodiments, the end of the housing 1 near the first end 21 of the rotating shaft 2 is disconnected from the first conductive ring 4, and the end of the housing 1 near the second end 22 of the rotating shaft 2 is connected to the second conductive ring 5. In this connection method, the electric drive system is in a state where the second conductive ring 5 is only installed at the motor output shaft end, and the shaft voltage at three points—the motor tail end, the motor output shaft end, and the area between the motor tail end and the output shaft end—can be acquired using an oscilloscope.

[0035] In some optional embodiments, the end of the housing 1 near the first end 21 of the rotating shaft 2 is connected to the first conductive ring 4, and the end of the housing 1 near the second end 22 of the rotating shaft 2 is connected to the second conductive ring 5. In this connection method, the electric drive system is in a state where the first conductive ring 4 is installed at the tail end of the motor, and the electric drive system is in a state where the second conductive ring 5 is installed at the output shaft end of the motor. The shaft voltage at three points—the tail end of the motor, the output shaft end of the motor, and the area between the tail end of the motor and the output shaft end—can be acquired using an oscilloscope.

[0036] In some optional embodiments, the first conductive ring 4 is provided with a first test line 41 and a first connecting line 42 of different colors. The first test line 41 is used to connect to the oscilloscope, and the first connecting line 42 is used to connect to the housing 1. The second conductive ring 5 is provided with a second test line 51 and a second connecting line 52 of different colors. The second test line 51 is used to connect to the oscilloscope, and the second connecting line 52 is used to connect to the housing 1. The first test line 41 and the first connecting line 42 are different colors. In one example, the first test line 41 is red, and the first connecting line 42 is black. The operator can distinguish the first test line 41 and the first connecting line 42 based on their colors, which is convenient for the operator to identify and connect. The second test line 51 and the second connecting line 52 are also different colors. In one example, the second test line 51 is red, and the second connecting line 52 is black. The operator can distinguish the second test line 51 and the second connecting line 52 based on their colors, which is convenient for the operator to identify and connect.

[0037] In some alternative embodiments, the first bearing 211 is connected to the positive terminal of the first channel of the oscilloscope via the first bearing wire 2111, and the second bearing 221 is connected to the positive terminal of the second channel of the oscilloscope via the second bearing wire 2211.

[0038] In some optional embodiments, a first housing wire 11 and a second housing wire 12 are respectively provided at both ends of the housing 1. The first housing wire 11 is used to connect to the first connecting line 42, and the second housing wire 12 is used to connect to the second connecting line 52. When the housing 1 needs to be connected to the first conductive ring 4, the first housing wire 11 is connected to the first connecting line 42, which is more convenient than the first connecting line 42 being directly connected to the housing 1. When the housing 1 needs to be connected to the second conductive ring 5, the second housing wire 12 is connected to the second connecting line 52, which is more convenient than the second connecting line 52 being directly connected to the housing 1.

[0039] Reference Figure 3 , Figure 3 This diagram illustrates the structure of an insulating base according to an embodiment of this application. In some optional embodiments, the housing 1 is provided with a first support assembly, which includes a column and an insulating base 13 connected to each other. The end of the column facing away from the insulating base 13 is connected to the housing 1. The first support assembly can support the housing 1. The insulating base 13 can be made of ceramic material. The insulating base 13 can prevent the housing 1 from conducting electricity with other components, thereby improving the accuracy of the test.

[0040] Reference Figure 4 , Figure 4 The diagram illustrates the structure of an insulating turntable according to an embodiment of this application. In some optional embodiments, an insulating turntable 23 is provided between the second end 22 of the rotating shaft 2 and the testing machine interface. The insulating turntable 23 can avoid the presence of wires between the rotating shaft 2 and the testing machine interface, thereby improving the accuracy of the test.

[0041] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A shaft voltage testing device for an electric drive system, characterized in that, include: The housing (1) has an inner cavity, and a stator (6) is provided inside the housing (1). A rotating shaft (2) is provided with a first end (21) and a second end (22) along the length direction of the rotating shaft (2). The rotating shaft (2) is located in the inner cavity of the stator (6). The first end (21) is rotatably connected to the housing (1) through a first bearing (211). The second end (22) extends out of the housing (1) and is rotatably connected to the housing (1) through a second bearing (221). The rotor (3) is connected to the rotating shaft (2) and corresponds to the stator (6); The first conductive ring (4) is connected to the housing (1) and sleeved on the first end (21), and the carbon brush of the first conductive ring (4) is in contact with the first end (21); The second conductive ring (5) is connected to the housing (1) and sleeved on the second end (22), and the carbon brush of the second conductive ring (5) is in contact with the second end (22); An oscilloscope has a channel for detecting voltage.

2. The shaft voltage testing device for an electric drive system according to claim 1, characterized in that, The oscilloscope is equipped with: The positive terminal of the first channel is used to connect to the first conductive ring (4), and the negative terminal of the first channel is used to connect to the first bearing (211) for testing the voltage at the tail end of the motor. The positive terminal of the second channel is used to connect to the second conductive ring (5), and the negative terminal of the second channel is used to connect to the second bearing (221) for testing the voltage at the output shaft end of the motor; The positive terminal of the third channel is used to connect to the first conductive ring (4), and the negative terminal of the third channel is used to connect to the second conductive ring (5) for testing the voltage between the tail end of the motor and the output shaft end.

3. The shaft voltage testing device for an electric drive system according to claim 2, characterized in that, The end of the housing (1) near the first end (21) of the rotating shaft (2) is disconnected from the first conductive ring (4), and the end of the housing (1) near the second end (22) of the rotating shaft (2) is disconnected from the second conductive ring (5).

4. The shaft voltage testing device for an electric drive system according to claim 2, characterized in that, The end of the housing (1) near the first end (21) of the rotating shaft (2) is connected to the first conductive ring (4), and the end of the housing (1) near the second end (22) of the rotating shaft (2) is disconnected from the second conductive ring (5).

5. The shaft voltage testing device for an electric drive system according to claim 2, characterized in that, The end of the housing (1) near the first end (21) of the rotating shaft (2) is disconnected from the first conductive ring (4), and the end of the housing (1) near the second end (22) of the rotating shaft (2) is connected to the second conductive ring (5).

6. The shaft voltage testing device for an electric drive system according to claim 2, characterized in that, The end of the housing (1) near the first end (21) of the rotating shaft (2) is connected to the first conductive ring (4), and the end of the housing (1) near the second end (22) of the rotating shaft (2) is connected to the second conductive ring (5).

7. The shaft voltage testing device for an electric drive system according to claim 1, characterized in that, The first conductive ring (4) is provided with a first test line (41) and a first connecting line (42) of different colors. The first test line (41) is used to connect to the oscilloscope, and the first connecting line (42) is used to connect to the housing (1). The second conductive ring (5) is provided with a second test line (51) and a second connecting line (52) of different colors. The second test line (51) is used to connect to the oscilloscope, and the second connecting line (52) is used to connect to the housing (1).

8. The shaft voltage testing device for an electric drive system according to claim 7, characterized in that, The housing (1) is provided with a first housing wire (11) and a second housing wire (12) at its two ends. The first housing wire (11) is used to connect to the first connecting line (42), and the second housing wire (12) is used to connect to the second connecting line (52).

9. The shaft voltage testing device for an electric drive system according to claim 1, characterized in that, The housing (1) is provided with a first support assembly, which includes a column and an insulating base (13) connected to each other. The end of the column away from the insulating base (13) is connected to the housing (1).

10. The shaft voltage testing device for an electric drive system according to claim 1, characterized in that, An insulating turntable (23) is provided between the second end (22) of the rotating shaft (2) and the interface of the testing machine.

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