Motor bearing voltage simulation device and method for bearing electrocorrosion test

Abstract

The invention discloses a motor bearing voltage simulation device and method for a bearing electrocorrosion test, and relates to the field of new energy automobiles. The problems that in the prior art, the disassembly and replacement process of a bearing in an intrusive measurement method is tedious and time-consuming, and deep research on the damage condition of the bearing under different operation conditions and key parameters is greatly limited are solved. The simulation device comprises a BUCK voltage regulating circuit, a three-bridge-arm inverter, a common-mode voltage output loop, a high-pass filtering loop, a bearing voltage simulation loop and a bearing voltage output loop. By utilizing a bearing voltage generation mechanism and combining cooperative work of the three-bridge-arm inverter and the rear-end bearing voltage simulation loop, the waveform of the bearing voltage can be reproduced completely, and the waveform can be adjusted according to needs, so that high flexibility and accuracy are provided for research and test. The method is also suitable for the field of actual motor bearing voltage simulation.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a motor bearing voltage simulation device and method for bearing electrical corrosion testing. Background Art

[0002] The key indicators for the development of electric drive systems for new energy vehicles are high power density and high efficiency. To achieve this goal, a higher voltage platform, such as 800V, higher frequency wide bandgap semiconductor devices, such as frequencies increased to 20kHz to 30kHz, and higher speed drive motors, such as speeds reaching or exceeding 20,000rpm, are required. However, the significant increase in bearing electrical stress brought about by these technological advances will lead to an increase in the problem of electrochemical corrosion of bearings, which will in turn cause early failure of bearings. The problem of electrochemical corrosion of bearings has become a key technical problem that needs to be urgently solved in the new energy vehicle industry, and it poses a major obstacle to the cross-generational upgrade of automotive electric drive systems. It is reported that the premature failure of bearings is the most serious problem, with more than 40% of motor failures attributed to bearing failure.

[0003] When studying the failure mechanisms caused by bearing currents, it is crucial to obtain clear bearing current signals. However, traditional invasive measurement methods face major challenges: they usually require customized modifications to the bearing fixtures and motor end covers, which not only involves multiple interference issues inside the motor, but also significantly increases the experimental costs. In addition, the disassembly and replacement of the bearings is cumbersome and time-consuming, which greatly limits the in-depth study of bearing damage under different operating conditions and critical parameters. Worse still, these methods may cause damage to the motor system itself, increasing the risk of the experiment. Therefore, developing a new measurement technology that can accurately capture the bearing current signal without destroying the integrity of the motor and bearings has become a technical problem that urgently needs to be solved in the research of electric drive systems for new energy vehicles. Summary of the invention

[0004] The present invention aims to solve the major challenges faced by the invasive measurement methods in the prior art: they usually require customized modifications to the bearing fixtures and motor end covers, which not only involves multiple interference issues inside the motor, but also significantly increases the experimental costs. In addition, the disassembly and replacement of the bearings is cumbersome and time-consuming, which greatly limits the in-depth study of bearing damage under different operating conditions and key parameters. The above methods may cause damage to the motor system itself, increasing the risk of the experiment.

[0005] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] Solution 1: The present invention proposes a motor bearing voltage simulation device for bearing electrical corrosion test, wherein the motor bearing voltage simulation device comprises a BUCK voltage regulation circuit, a three-bridge arm inverter, a common mode voltage output circuit, a high-pass filter circuit, a bearing voltage simulation circuit and a bearing voltage output circuit;

[0007] The positive electrode of the DC power supply in the BUCK voltage regulation circuit is connected to one side of the switch MOS tube Qv, the positive electrode of the diode D1 is connected to the negative electrode of the DC power supply, and the negative electrode of the diode D1 is connected to the other side of the switch MOS tube Qv;

[0008] The switch MOS tube Qv is simultaneously connected to one side of the inductor L1, the other side of the inductor L1 is connected to the upper end of the capacitor C4, the lower end of the capacitor C4 is connected to the upper end of the capacitor C5, the lower end of the capacitor C5 is connected to the negative electrode of the DC power supply, and the negative electrode of the bearing voltage output terminal is obtained from the connection point of the capacitor C4 and the capacitor C5;

[0009] The upper end of the three-arm inverter DC measurement is connected to the upper end of the capacitor C4, and the lower end of the three-arm inverter DC measurement is connected to the lower end of the capacitor C5; the three-phase output ends are respectively connected to one side of the three resistors R1, R2, and R3 of the common mode voltage output circuit;

[0010] The other sides of the three resistors R1, R2, and R3 in the common-mode voltage output loop are respectively connected to the left sides of the three capacitors C1, C2, and C3, and the other sides of the capacitors C1, C2, and C3 are connected to the common-mode voltage output terminal;

[0011] In the high-pass filter circuit, the capacitor C hfp One side is connected to the common-mode voltage output terminal, capacitor C hfp The other end of the capacitor C hfp The two ends of the relay K1 are connected to the two ends of the relay K2; the lower end of the relay K2 is connected to the resistor R hfp The upper end of the resistor R hfp The lower end is connected to the negative pole of the bearing voltage output terminal;

[0012] In the bearing voltage simulation circuit, the capacitor C wr One side is connected to the right end of relay K1, capacitor C wr The other end of the capacitor is connected to the positive electrode of the bearing voltage output terminal; rs The upper and lower ends are respectively connected to the positive pole of the bearing voltage output circuit and the negative pole of the bearing voltage output circuit.

[0013] Furthermore, a preferred embodiment is provided, in which each phase in the common-mode voltage output circuit is a resistor-capacitor series structure, and the output endpoint is a common connection point on one side of the three-phase capacitor, for obtaining the common-mode voltage.

[0014] Furthermore, a preferred implementation is provided, in which the three-phase resistors and capacitors in the common-mode voltage output loop have the same size.

[0015] Furthermore, a preferred implementation manner is provided, wherein the three resistors R1, R2, and R3 in the common-mode voltage output loop are all power non-inductive resistors.

[0016] Furthermore, a preferred embodiment is provided, wherein the bearing voltage simulation circuit further includes a designed capacitor C rs Parameters and Capacitance C ws Parameters of the step.

[0017] Furthermore, a preferred embodiment is provided, wherein the bearing voltage output circuit is connected by contacting the negative electrode of the bearing voltage output terminal through a pressing plate, and the positive electrode of the bearing voltage output terminal is connected to the rotating shaft through a conductive brush.

[0018] Furthermore, a preferred implementation manner is provided, wherein a voltage-equalizing resistor is connected in parallel across the capacitor C4 and the capacitor C5.

[0019] Solution 2: A motor bearing voltage simulation method for bearing electrical corrosion test, characterized in that the motor bearing voltage simulation method is implemented by using any device described in Solution 1, and the method is:

[0020] The two bearing voltages generated on the bearing are connected to the output terminals of the device, and the two bearing voltages are applied to the bearing to complete the motor bearing voltage simulation for the bearing electrical corrosion test.

[0021] Furthermore, a preferred embodiment is provided, wherein the two bearing voltages include a bearing voltage having the same shape as the common mode voltage and a peak-shaped high-frequency shaft voltage.

[0022] The present invention is beneficial in that:

[0023] In order to solve the problems in the prior art, the present invention proposes a motor bearing voltage simulation device for bearing electrical corrosion test. The bearing voltage simulation device can be used in conjunction with a single bearing test platform. The bearing voltage simulation device applies the electrical stress to the bearing during the actual motor operation, and the bearing test platform applies mechanical stress at the same time, thereby obtaining the same working conditions as the actual motor bearing, and conducting electrical corrosion experiments on single bearings. Compared with the invasive measurement scheme in the prior art, this method combines the accuracy of traditional invasive measurement methods with the convenience of bearing replacement, making long-term and repeated testing possible. In addition, the bearing voltage simulator also supports long-term continuous testing of bearings. After the test is completed, a comprehensive analysis of the bearing damage will help reveal the mechanism of bearing current-induced damage, thereby providing important technical support for the development of more reliable and efficient motors and drive systems.

[0024] The motor bearing voltage simulation device and method for bearing electrical corrosion test described in the present invention utilizes the bearing voltage generation mechanism, combines the coordinated work of the three-arm inverter and the rear-end bearing voltage simulation circuit, and can completely reproduce the waveform of the bearing voltage, and these waveforms can be adjusted as needed. This precise waveform reproduction capability provides a high degree of flexibility and accuracy for research and testing.

[0025] The bearing voltage simulator of the present invention has a simple design, a small number of components, a compact structure, and is easy to integrate and deploy. In addition, by adjusting the parameters in the simulation loop, the present invention can adapt to the bearing voltage reproduction requirements of different motors, thereby broadening its application range.

[0026] The motor bearing voltage simulation device for bearing electrical corrosion test described in the present invention provides a new experimental platform for motor bearing electrical corrosion research without relying on a complete motor system. The present invention does not require any modification of the motor, and the bearing electrical corrosion experiment can be directly performed through parameter extraction. This not only reduces the complexity and cost of the experiment, but also avoids possible damage to the motor, making the experimental process more efficient and safe. The design of the simulation device not only reduces the experimental cost, improves the flexibility and efficiency of the experiment, but also provides a more accurate simulation environment for the study of motor bearing electrical corrosion phenomena without damaging the integrity of the motor.

[0027] The present invention is also applicable to the field of bearing voltage simulation of actual motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 This is a schematic diagram of an ideal bearing voltage waveform described in the tenth embodiment.

[0030] Figure 2 This is a schematic diagram of an ideal high-frequency bearing voltage waveform described in the tenth embodiment.

[0031] Figure 3 This is a schematic diagram of the high-frequency common-mode equivalent circuit described in the tenth embodiment.

[0032] Figure 4 This is a schematic diagram of the structure of the bearing voltage simulator described in the tenth embodiment.

[0033] Figure 5 This is a schematic diagram of the measured simulated bearing voltage output waveform described in the tenth embodiment.

[0034] Figure 6 This is a schematic diagram of the measured simulated high-frequency bearing voltage output waveform described in the tenth embodiment.

[0035] In the figure, there are BUCK voltage regulating circuit 1, three-bridge arm inverter 2, common mode voltage output circuit 3, high pass filter circuit 4, bearing voltage simulation circuit 5, and bearing voltage output circuit 6. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0037] Embodiment 1. This embodiment provides a motor bearing voltage simulation device for bearing electrical corrosion test, the motor bearing voltage simulation device comprising a BUCK voltage regulation circuit 1, a three-bridge arm inverter 2, a common mode voltage output circuit 3, a high-pass filter circuit 4, a bearing voltage simulation circuit 5 and a bearing voltage output circuit 6;

[0038] In the BUCK voltage regulation circuit 1, the positive electrode of the DC power supply is connected to one side of the switch MOS tube Qv, the positive electrode of the diode D1 is connected to the negative electrode of the DC power supply, and the negative electrode of the diode D1 is connected to the other side of the switch MOS tube Qv;

[0039] The switch MOS tube Qv is simultaneously connected to one side of the inductor L1, the other side of the inductor L1 is connected to the upper end of the capacitor C4, the lower end of the capacitor C4 is connected to the upper end of the capacitor C5, the lower end of the capacitor C5 is connected to the negative electrode of the DC power supply, and the negative electrode of the bearing voltage output terminal is obtained from the connection point of the capacitor C4 and the capacitor C5;

[0040] The upper end of the three-arm inverter 2 is connected to the upper end of the capacitor C4, and the lower end of the three-arm inverter is connected to the lower end of the capacitor C5; the three-phase output ends are respectively connected to one side of the three resistors R1, R2, and R3 of the common mode voltage output circuit;

[0041] The other sides of the three resistors R1, R2, and R3 in the common-mode voltage output loop 3 are connected to the left sides of the three capacitors C1, C2, and C3 respectively, and the other sides of the capacitors C1, C2, and C3 are connected to the common-mode voltage output terminal;

[0042] The capacitor C in the high-pass filter circuit 4 hfp One side is connected to the common-mode voltage output terminal, capacitor C hfpThe other end of the capacitor C hfp The two ends of the relay K1 are connected to the two ends of the relay K2; the lower end of the relay K2 is connected to the resistor R hfp The upper end of the resistor R hfp The lower end is connected to the negative pole of the bearing voltage output terminal;

[0043] The capacitor C in the bearing voltage simulation loop 5 wr One side is connected to the right end of relay K1, capacitor C wr The other end of the capacitor is connected to the positive electrode of the bearing voltage output terminal; rs The upper and lower ends are respectively connected to the positive pole of the bearing voltage output circuit and the negative pole of the bearing voltage output circuit 6.

[0044] Embodiment 2. This embodiment is a further limitation of the motor bearing voltage simulation device for bearing electrical corrosion test described in embodiment 1. Each phase in the common-mode voltage output circuit 3 is a resistor-capacitor series structure, and the output endpoint is a common connection point on one side of the three-phase capacitor, which is used to obtain the common-mode voltage.

[0045] Embodiment 3: This embodiment further limits the motor bearing voltage simulation device for bearing electrical corrosion test described in Embodiment 2, and the three-phase resistors and capacitors in the common-mode voltage output circuit 3 have the same size.

[0046] Embodiment 4: This embodiment further limits the motor bearing voltage simulation device for bearing electrical corrosion test described in embodiment 1. The three resistors R1, R2, and R3 in the common-mode voltage output loop 3 are all power non-inductive resistors.

[0047] Embodiment 5: This embodiment further limits the motor bearing voltage simulation device for bearing electrical corrosion test described in Embodiment 1. The bearing voltage simulation circuit 5 further includes a designed capacitor C rs Parameters and Capacitance C ws Parameters of the step.

[0048] Embodiment 6. This embodiment is a further limitation of the motor bearing voltage simulation device for bearing electrical corrosion test described in embodiment 1. The bearing voltage output circuit 6 is connected in a manner that the negative pole of the bearing voltage output terminal is in contact with the pressure plate, and the positive pole of the bearing voltage output terminal is connected to the rotating shaft through a conductive brush.

[0049] Embodiment 7: This embodiment further limits the motor bearing voltage simulation device for bearing electrical corrosion test described in Embodiment 1, and a voltage-equalizing resistor is further connected in parallel across the capacitor C4 and the capacitor C5.

[0050] Embodiment 8: This embodiment proposes a motor bearing voltage simulation method for bearing electrical corrosion test, the motor bearing voltage simulation method is implemented by using the device described in any one of Embodiment 1 to Embodiment 7, the method is:

[0051] The two bearing voltages generated on the bearing are connected to the output terminals of the device, and the two bearing voltages are applied to the bearing to complete the motor bearing voltage simulation for the bearing electrical corrosion test.

[0052] Embodiment 9: This embodiment further limits the motor bearing voltage simulation method for bearing electrical corrosion test described in embodiment 8, wherein the two bearing voltages include a bearing voltage having the same shape as the common mode voltage and a spike-shaped high-frequency shaft voltage.

[0053] Implementation Method 10: See Figures 1 to 6 This embodiment is described. This embodiment provides an example, which is used to explain the above-mentioned embodiments 1 to 9. The specific example is as follows:

[0054] In order to solve the problems existing in the above-mentioned technologies, this embodiment proposes a motor bearing voltage simulation device for bearing electrical corrosion test. The device can realize comprehensive simulation of bearing voltage, including: waveform modulation ratio, amplitude, and switching frequency can all be adjusted online. This effectively overcomes the difficulties in the process of bearing electrical stress simulation. Its working principle is simple and clear, and the output results are highly accurate, providing an efficient and reliable solution for motor bearing electrical corrosion research.

[0055] In the motor drive system using pulse width modulation (PWM) variable frequency power supply, high-frequency common-mode interference often affects the drive system through the coupling circuit inside the motor, generating two types of bearing voltages on the bearings. One is the bearing voltage with the same shape as the common-mode voltage, such as Figure 1 The other is a spike-shaped high-frequency shaft voltage as shown in Figure 2 As shown. To meet this challenge, the simulation device described in this embodiment can accurately simulate the bearing voltage and high-frequency shaft voltage generated inside the motor. In addition, the device can directly apply the simulated bearing voltage to the bearing through its output terminal, thereby providing an effective experimental platform for interference research of motor drive systems. This innovative design not only enhances the controllability of the experiment, but also provides a powerful tool for in-depth analysis and resolution of bearing electrical corrosion problems in motor drive systems.

[0056] The motor common mode equivalent circuit is as follows Figure 3 As shown, w is the winding, r is the rotating shaft, s is the housing, V com is the common mode voltage of the inverter output, C ws is the parasitic capacitance between the stator winding and the housing, Crs is the parasitic capacitance between the housing and the rotating shaft, C wr is the parasitic capacitance between the stator winding and the rotating shaft, C b,d and C b,nd Represents the capacitance of the bearing drive end and non-drive end respectively. Bearing voltage V b The ratio to the common-mode voltage is a constant, namely BVR, and the two waveforms have the same shape, as shown in formula (1).

[0057] This embodiment proposes a motor bearing voltage simulation technology based on the bearing voltage formation mechanism, and its structure is as follows: Figure 4 As shown, it includes a BUCK voltage regulating circuit, a three-bridge arm inverter, a common-mode voltage output circuit, a high-pass filter circuit, a bearing voltage simulation circuit and a bearing voltage applying device.

[0058] The three bridge arms of the inverter are responsible for controlling the frequency and waveform of the common-mode voltage. Figure 1 The common-mode voltage waveform shown in FIG. 1 is similar to that shown in FIG. 1 , but in an actual motor, the jump time of the common-mode voltage will vary in each cycle according to the different positions of the SVPWM control sector. By accurately controlling the switching state of the three-arm inverter, the present invention can simulate the same common-mode voltage waveform as that in the actual motor. The BUCK voltage regulation circuit is connected to the back end of the DC power supply to achieve precise regulation of the DC power supply voltage, thereby achieving regulation of the bearing voltage amplitude.

[0059] Furthermore, the common-mode voltage output circuit is specially designed, and compared with the common-mode voltage obtained by the actual motor at the neutral point of the motor, the simulation circuit is superior in both volume and effect. Each phase of the common-mode voltage simulation circuit is a resistor-capacitor series structure, and the right ends of the three phases are connected to the same point to obtain the common-mode voltage. Among them, the resistors are all power non-inductive resistors. These resistors not only meet the heat dissipation performance requirements of the circuit, but also introduce necessary parasitic inductance into the common-mode voltage output circuit to avoid resonance effects in the circuit. The specially debugged loop parameters make the resistance value small enough to suppress high-frequency undamped voltage oscillations in the common-mode output circuit. The capacitor has a large impedance, which is used to suppress the three-phase loop current, thereby improving the working efficiency of the bearing voltage simulator and the reliability of long-term operation.

[0060] like Figure 4 As shown in the figure, when it is necessary to simulate the high-frequency cyclic shaft voltage, the relay K1 is opened and the relay K2 is closed by remotely operating the relay, and the high-pass filter circuit is connected to the simulator; when it is necessary to simulate the bearing voltage, the relay K1 is closed and the relay K2 is opened to cut off the high-pass filter circuit. In addition, the bearing voltage simulation circuit can adjust the capacitance parameters in the simulation circuit according to the different parasitic parameters of the actual motor to meet different usage requirements.

[0061] Furthermore, in the bearing voltage simulation loop, C can be designed according to the parasitic capacitance of the actual motor to be simulated. rs Parameters and C ws Parameters are used to study the instantaneous pulse current amplitude of the bearing EDM discharge current, so as to meet the research needs of bearing electrical corrosion of different motors from the underlying logic of hardware design.

[0062] Furthermore, in terms of the bearing voltage output device, the outer ring of the bearing is reliably in contact with the negative pole of the bearing voltage output end through the pressing plate, while the positive pole of the bearing voltage output is connected to the rotating shaft through the conductive brush. The reliable contact between the pressing plate, the conductive brush and the inner and outer rings of the bearing ensures that the simulated bearing voltage can be stably output to the test bearing.

[0063] Compared with the bearing voltage generation mechanism, the bearing voltage simulator has no C wg parameter, this is because C wg The parameters do not affect the bearing voltage waveform and bearing current in the simulator. Therefore, the parasitic capacitance between the stator winding and the housing is not designed in the simulator.

[0064] Furthermore, in the design of the bearing voltage simulation circuit, the present invention pays special attention to the steady-state solution of the output voltage. Therefore, the capacitance of the capacitor is determined according to the principle of the phasor method. The BUCK voltage gain M is given by formula (2); in order to obtain the common-mode voltage, it is necessary to ensure that the three-phase capacitors and resistors are the same, thereby obtaining formula (3); according to the circuit principle, U is calculated b with U o The voltage divider ratio between them is shown in formula (4); due to the bearing capacitance C b is relatively small and can be ignored in the calculation process, so we get formula (5); further combining formula (5) with formula (2), we get the final bearing voltage output and U dc The relationship between is shown in formula (6). The bearing voltage output coefficient N is defined as formula (7).

[0065] Through this bearing voltage output coefficient N, it can be clearly understood that in the hardware design stage, the capacitance of each capacitor component in the circuit can be adjusted, or in the software end, the MOS tube Q can be adjusted. v The duty cycle is used to change the voltage gain, thereby achieving the purpose of changing the output bearing voltage. This method provides a flexible and accurate control mechanism, so that the present embodiment can adapt to different experimental requirements and application scenarios.

[0066]

[0067] C1=C2=C3 (3)

[0068]

[0069]

[0070] When designing a high-pass filter, considering that the equivalent oscillation frequency of the high-frequency circulating current is in the range of 0.64MHz to 1.6MHz, the resistor R hfp With capacitor C hfp The selection of is critical. To ensure that the filter can work effectively within this frequency range, the parameter range given by formula (8) can be used for design. Such a design will help ensure that the filter can accurately filter out low-frequency noise while allowing high-frequency circulating bearing voltage to pass.

[0071]

[0072] In this embodiment, capacitors C4 and C5 are selected as DC bus support capacitors with high withstand voltage and large capacitance. This selection helps to ensure the stability and reliability of the circuit, especially when dealing with high voltage applications. In order to maintain a constant neutral point potential between C4 and C5, we connected a voltage equalizing resistor in parallel across C4 and C5. This design strategy is critical because it ensures the upper and lower symmetry of the output bearing voltage waveform and avoids the problem of potential drift. Through this design, the present embodiment is able to provide a stable and symmetrical bearing voltage output, which is critical for accurately simulating and studying the electrical corrosion phenomenon of motor bearings, and further improves the accuracy and reliability of the simulation results.

[0073] Embodiment 1:

[0074] When simulating the bearing voltage of the actual motor, the bearing voltage is small and basically remains constant. In order to realize the function of outputting the simulated bearing voltage, the specific implementation can be completed by sharing devices with the actual motor controller. Specifically, the front-end Buck circuit and the three-phase bridge inverter circuit need to be removed from the bearing voltage simulator, and the output end of the actual motor controller needs to be connected to the left end of the three resistors R1, R2, and R3 in the common-mode voltage output loop. The rest remains unchanged, and the parameter design can be adjusted according to the parasitic parameters of the actual motor to obtain the same bearing voltage as the actual motor.

[0075] Embodiment 2:

[0076] In the scenario where a larger bearing voltage needs to be applied, the target voltage value can be directly entered in the bearing simulator controller according to the bearing voltage ratio of the motor system itself and the required bearing voltage. The software will automatically adjust the duty cycle D in the BUCK voltage regulator circuit controller according to the input voltage, thereby adjusting the bearing voltage output coefficient N to achieve the required experimental conditions.

[0077] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0078] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A motor bearing voltage simulation device for bearing electrical corrosion test, characterized in that: The motor bearing voltage simulation device comprises a BUCK voltage regulating circuit (1), a three-bridge arm inverter (2), a common mode voltage output circuit (3), a high-pass filter circuit (4), a bearing voltage simulation circuit (5) and a bearing voltage output circuit (6); In the BUCK voltage regulation circuit (1), the positive electrode of the DC power supply is connected to one side of the switch MOS tube Qv, the positive electrode of the diode D1 is connected to the negative electrode of the DC power supply, and the negative electrode of the diode D1 is connected to the other side of the switch MOS tube Qv; The switch MOS tube Qv is simultaneously connected to one side of the inductor L1, the other side of the inductor L1 is connected to the upper end of the capacitor C4, the lower end of the capacitor C4 is connected to the upper end of the capacitor C5, the lower end of the capacitor C5 is connected to the negative electrode of the DC power supply, and the negative electrode of the bearing voltage output terminal is obtained from the connection point of the capacitor C4 and the capacitor C5; The DC upper end of the three-arm inverter (2) is connected to the upper end of the capacitor C4, and the DC lower end of the three-arm inverter (2) is connected to the lower end of the capacitor C5; the three-phase output ends are respectively connected to one side of the three resistors R1, R2, and R3 of the common mode voltage output circuit (3); The other sides of the three resistors R1, R2, and R3 in the common-mode voltage output loop (3) are respectively connected to the left sides of the three capacitors C1, C2, and C3, and the other sides of the capacitors C1, C2, and C3 are connected to the common-mode voltage output terminal; The capacitor C in the high-pass filter circuit (4) hfp One side is connected to the common-mode voltage output terminal, capacitor C hfp The other end of the capacitor C hfp The two ends of the relay K1 are connected to the two ends of the relay K2; the lower end of the relay K2 is connected to the resistor R hfp The upper end of the resistor R hfp The lower end is connected to the negative pole of the bearing voltage output terminal; In the bearing voltage simulation circuit (5), the capacitor C wr One side is connected to the right end of relay K1, capacitor C wr The other end of the capacitor is connected to the positive electrode of the bearing voltage output terminal; rs The upper and lower ends are respectively connected to the positive pole of the bearing voltage output circuit (6) and the negative pole of the bearing voltage output circuit (6).

2. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 1, characterized in that: Each phase in the common mode voltage output circuit (3) is a resistor and capacitor series structure, and the output endpoint is a common connection point on one side of the three-phase capacitor, which is used to obtain the common mode voltage.

3. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 2, characterized in that: The three-phase resistors and capacitors in the common-mode voltage output circuit (3) have the same size.

4. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 1, characterized in that: The three resistors R1, R2 and R3 in the common-mode voltage output loop (3) are all power non-inductive resistors.

5. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 1, characterized in that: The bearing voltage simulation circuit (5) also includes a designed capacitor C rs Parameters and Capacitance C ws Parameters of the step.

6. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 1, characterized in that: The bearing voltage output circuit (6) is connected in a manner that the pressure plate contacts the negative electrode of the bearing voltage output end, and the positive electrode of the bearing voltage output end is connected to the rotating shaft through a conductive brush.

7. The motor bearing voltage simulation device for bearing electrical corrosion test according to claim 1, characterized in that: A voltage-equalizing resistor is connected in parallel between the two ends of the capacitor C4 and the capacitor C5.

8. A motor bearing voltage simulation method for bearing electrical corrosion test, characterized in that: The motor bearing voltage simulation method is implemented by using the device according to any one of claims 1 to 7, and the method is: The two bearing voltages generated on the bearing are connected to the output terminals of the device, and the two bearing voltages are applied to the bearing to complete the motor bearing voltage simulation for the bearing electrical corrosion test.

9. The motor bearing voltage simulation method for bearing electrical corrosion test according to claim 8, characterized in that: The two types of bearing voltages include a bearing voltage having the same shape as the common mode voltage and a peak-shaped high-frequency shaft voltage.

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