A motor bearing voltage simulation device and method for bearing electrochemical corrosion test

Abstract

A motor bearing voltage simulation device and method for bearing electrochemical corrosion test, relate to the field of new energy vehicles. The problems of the existing technology, such as the complicated and time-consuming disassembly and replacement process of the bearing in the invasive measurement method, which greatly limits the in-depth study of bearing damage under different operating conditions and key parameters, 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 filter loop, a bearing voltage simulation loop and a bearing voltage output loop; by utilizing the bearing voltage generation mechanism, combined with the cooperative work of the three-bridge-arm inverter and the rear bearing voltage simulation loop, the waveform of the bearing voltage can be completely reproduced, and these waveforms can be adjusted according to the needs, providing high flexibility and accuracy for research and testing. It is also suitable for the field of bearing voltage simulation of actual motors.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of new energy vehicles, and particularly relates to a motor bearing voltage simulation device and method for bearing electrochemical corrosion testing. BACKGROUND

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

[0003] In studying the failure mechanism caused by bearing current, it is essential to obtain a clear bearing current signal. However, traditional invasive measurement methods face major challenges: they usually require customized modification of the bearing fixing device and the motor end cover, which not only involves multiple aspects of interference with the motor interior, but also significantly increases the experimental cost. In addition, the disassembly and replacement process of the bearing is complicated and time-consuming, greatly limiting in-depth study of bearing damage under different operating conditions and key parameters. Worse still, these methods can 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 damaging the integrity of the motor and bearing has become an urgent technical problem to be solved in the research of new energy vehicle electric drive systems. SUMMARY

[0004] The application is to solve the problem that the invasive measurement method in the prior art faces major challenges: they usually require customized modification of the bearing fixing device and the motor end cover, which not only involves multiple aspects of interference with the motor interior, but also significantly increases the experimental cost. In addition, the disassembly and replacement process of the bearing is complicated and time-consuming, greatly limiting in-depth study of bearing damage under different operating conditions and key parameters. The above method can cause damage to the motor system itself, increasing the risk of the experiment.

[0005] To solve the above technical problems, the application is implemented by the following technical scheme:

[0006] Scheme one, the application provides a motor bearing voltage simulation device for bearing electric corrosion test, the motor bearing voltage simulation device includes BUCK voltage regulating circuit, three bridge arm inverter, common mode voltage output loop, high pass filter loop, bearing voltage simulation loop and bearing voltage output loop;

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

[0008] The switch MOS tube Qv is 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 pole of the DC power supply, and the connection point of the capacitor C4 and the capacitor C5 is led out to obtain the negative pole of the bearing voltage output end;

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

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

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

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

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

[0014] Further, a preferred embodiment is provided, wherein the three-phase resistance-capacitance in the common-mode voltage output circuit has the same size.

[0015] Further, a preferred embodiment is provided, wherein the three resistors R1, R2, R3 in the common-mode voltage output circuit are all power non-inductive resistors.

[0016] Further, a preferred embodiment is provided, wherein the bearing voltage simulation circuit further comprises a design capacitor C rs The parameter is associated with the capacitor C ws The parameter is associated with the capacitor C

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

[0018] Further, a preferred embodiment is provided, wherein the capacitor C4 and the capacitor C5 are further connected in parallel with a voltage equalizing resistor.

[0019] Scheme II, a motor bearing voltage simulation method for bearing electric corrosion test, characterized in that the motor bearing voltage simulation method is realized by using the device in any one of schemes I, and the method is:

[0020] The two kinds of bearing voltages generated on the bearing are connected to the output terminal of the device, and the two kinds of bearing voltages are applied to the bearing, thereby completing the motor bearing voltage simulation for the bearing electric corrosion test.

[0021] Further, a preferred embodiment is provided, wherein the two kinds of bearing voltages include a bearing voltage with the same shape as the common-mode voltage and a high-frequency shaft voltage with a sharp peak.

[0022] The present application has the advantages of:

[0023] The present application provides a motor bearing voltage simulation device for bearing electric corrosion test to solve the problems in the prior art. The bearing voltage simulation device can be used in combination with a single bearing test platform. The bearing voltage simulation device applies the electric stress on the bearing during actual motor operation, while the bearing test platform applies mechanical stress, so as to obtain the same working condition as the actual motor bearing, and the single bearing is subjected to electric corrosion test. Compared with the invasive measurement scheme in the prior art, this method combines the accuracy of the traditional invasive measurement method and the convenience of bearing replacement, so that long-term and repeated tests are possible. In addition, the bearing voltage simulator also supports long-term continuous testing of the bearing. After the test is completed, a comprehensive analysis of the bearing damage will help to reveal the mechanism of bearing current-induced damage, thereby providing important technical support for developing more reliable and efficient motors and drive systems.

[0024] The motor bearing voltage simulation device and method for bearing electrocorrosion test according to the application utilizes the bearing voltage generation mechanism, and the coordinated work of the three-bridge-arm inverter and the rear-end bearing voltage simulation loop, so that the waveform of the bearing voltage can be completely reproduced, and the waveform can be adjusted as needed.

[0025] The bearing voltage simulator according to the application has simple design, small number of devices, compact structure, and is easy to integrate and deploy.

[0026] The motor bearing voltage simulation device for bearing electrocorrosion test according to the application provides a new experimental platform for motor bearing electrocorrosion research without relying on a complete motor system. The application does not need to modify the motor in any way, and the bearing electrocorrosion experiment can be directly performed through parameter extraction. This not only reduces the complexity and cost of the experiment, but also avoids 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 research of motor bearing electrocorrosion phenomenon without damaging the integrity of the motor.

[0027] The application is also suitable for the field of bearing voltage simulation of actual motors. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments.

[0029] Figure 1 The ideal bearing voltage waveform diagram according to the tenth embodiment.

[0030] Figure 2 The ideal high-frequency bearing voltage waveform diagram according to the tenth embodiment.

[0031] Figure 3 The high-frequency common-mode equivalent circuit diagram according to the tenth embodiment.

[0032] Figure 4 The bearing voltage simulator structure diagram according to the tenth embodiment.

[0033] Figure 5 This is a schematic diagram of the measured simulated bearing voltage output waveform as described in Implementation Method 10.

[0034] Figure 6 This is a schematic diagram of the measured simulated high-frequency bearing voltage output waveform as described in Implementation Method 10.

[0035] In the diagram, BUCK voltage regulation circuit 1, three-bridge inverter 2, common-mode voltage output circuit 3, high-pass filter circuit 4, bearing voltage simulation circuit 5, and bearing voltage output circuit 6 are shown. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0037] Implementation Method 1: This implementation method provides a motor bearing voltage simulation device for bearing electro-corrosion testing. The motor bearing voltage simulation device includes a BUCK voltage regulating circuit 1, a three-bridge 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 terminal of the DC power supply is connected to one side of the switching MOSFET Qv, the positive terminal of diode D1 is connected to the negative terminal of the DC power supply, and the negative terminal of diode D1 is connected to the other side of the switching MOSFET Qv.

[0039] The switching MOSFET Qv is connected to one side of inductor L1, and the other side of inductor L1 is connected to the upper end of capacitor C4. The lower end of capacitor C4 is connected to the upper end of capacitor C5, and the lower end of capacitor C5 is connected to the negative terminal of DC power supply. The negative terminal of bearing voltage output is obtained from the connection point of capacitor C4 and capacitor C5.

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

[0041] The other side of the three resistors R1, R2, and R3 in the common-mode voltage output circuit 3 is connected to the left side of the three capacitors C1, C2, and C3, respectively, and the other side of the capacitors C1, C2, and C3 is connected to the common-mode voltage output terminal.

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

[0043] One side of the capacitor C wr in the bearing voltage simulation circuit 5 is connected to the right end of the relay K1, and the other end of the capacitor C rs is connected to the positive pole of the bearing voltage output end; the upper and lower ends of the capacitor C rs 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 II, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment I, each phase in the common mode voltage output circuit 3 is resistance-capacitance series structure, and the output end point is the common connection point of one side of three-phase capacitor, for obtaining common mode voltage.

[0045] Embodiment III, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment II, the three-phase resistance-capacitance in the common mode voltage output circuit 3 is the same size.

[0046] Embodiment IV, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment I, the three resistors R1, R2 and R3 in the common mode voltage output circuit 3 are all power inductance-free resistors.

[0047] Embodiment V, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment I, the bearing voltage simulation circuit 5 further includes a design capacitor C rs with capacitor C ws parameters.

[0048] Embodiment VI, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment I, the connection mode of the bearing voltage output circuit 6 is that the negative pole of the bearing voltage output end is contacted through the pressing sheet, and the positive pole of the bearing voltage output end is connected to the rotating shaft through the conductive brush.

[0049] Embodiment VII, the embodiment is further limited to the motor bearing voltage simulation device for bearing electric corrosion test in the embodiment I, the capacitor C4 and the capacitor C5 are further connected in parallel with the voltage equalizing resistor.

[0050] Embodiment eight, the embodiment proposes a motor bearing voltage simulation method for bearing electrocorrosion test, the motor bearing voltage simulation method is realized by the device of any one of the embodiments seven of the embodiment one, the method is:

[0051] The two bearing voltages generated on the bearing are connected to the output terminal of the device, and the two bearing voltages are applied to the bearing, completing the motor bearing voltage simulation of the bearing electrocorrosion test.

[0052] Embodiment nine, the embodiment is a further limitation of the motor bearing voltage simulation method for bearing electrocorrosion test of the embodiment eight, the two bearing voltages include the bearing voltage with the same shape as the common mode voltage and the high-frequency shaft voltage with the peak shape.

[0053] Embodiment ten, see Figures 1 to 6 The embodiment is explained, the embodiment proposes an embodiment for explaining the above-mentioned embodiments one to nine, and the embodiment is specifically:

[0054] The embodiment is proposed to solve the above-mentioned technical problems, a motor bearing voltage simulation device for bearing electrocorrosion test. The device can realize the overall simulation of the bearing voltage, including: waveform modulation ratio, amplitude, switching frequency can be adjusted online. Thus, the problem in the process of bearing electric stress simulation is effectively overcome. Its working principle is simple and clear, and the output result has high accuracy, which provides an efficient and reliable solution for motor bearing electrocorrosion 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, and two kinds of bearing voltages are generated on the bearing. One is the bearing voltage with the same shape as the common mode voltage, as shown in Figure 1 , and the other is the high-frequency shaft voltage with the peak shape, as shown in Figure 2 . In order to cope with this challenge, the simulation device of the 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 the interference research of motor drive system. This innovative design not only enhances the controllability of the experiment, but also provides a powerful tool for in-depth analysis and solution of the bearing electrocorrosion problem in motor drive system.

[0056] The motor common mode equivalent circuit is shown in Figure 3 , wherein w is the winding, r is the rotating shaft, s is the shell, V com is the common mode voltage output by the inverter, C ws is the parasitic capacitance between the stator winding and the shell, Crs C is the parasitic capacitance between the motor housing and the rotating shaft wr C is the parasitic capacitance between the stator winding and the rotating shaft b,d C is the parasitic capacitance between the stator winding and the rotating shaft b,nd C and C represent the capacitances of the bearing drive end and the non-drive end, respectively. The bearing voltage V b The ratio of the common-mode voltage to the bearing voltage is a constant, i.e. BVR, and the two waveforms are the same in shape, as shown in equation (1).

[0057] The present embodiment proposes a motor bearing voltage simulation technology based on the bearing voltage formation mechanism, as shown in Figure 4 The structure includes a BUCK voltage regulation circuit, a three-bridge-arm inverter, a common-mode voltage output loop, a high-pass filter loop, a bearing voltage simulation loop, and a bearing voltage application device.

[0058] The three bridge arms of the inverter are responsible for controlling the frequency and waveform of the common-mode voltage. Although the common-mode voltage waveform is similar to that shown in Figure 1 However, in an actual motor, the transition time of the common-mode voltage varies within each cycle depending on the different positions of the SVPWM control sector. By precisely controlling the switching state of the three-bridge-arm inverter, the present invention can simulate the same common-mode voltage waveform as in an actual motor. The back end of the DC power supply is connected to the BUCK voltage regulation circuit, which can precisely regulate the DC power supply voltage and thus adjust the bearing voltage amplitude.

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

[0060] As shown in Figure 4 When simulating a high-frequency cyclic shaft voltage, the high-pass filter loop is connected to the simulator by remotely operating the relay to open the relay K1 and close the relay K2. When simulating the bearing voltage, the high-pass filter loop is cut off by closing the relay K1 and opening the relay K2. In addition, the bearing voltage simulation loop can adjust the capacitance parameters in the simulation loop according to different parasitic parameters of the actual motor to meet different use requirements.

[0061] Further, in the bearing voltage simulation circuit, the size of the parasitic capacitance of the motor can be simulated according to the actual needs rs Parameter and C ws Parameter, and then research the instantaneous pulse current amplitude of the bearing EDM discharge current, to meet the needs of bearing electrochemical corrosion research of different motors from the bottom logic of hardware design.

[0062] Further, in terms of bearing voltage output device, the bearing outer ring is in reliable contact with the negative electrode of the bearing voltage output end through a pressing sheet, while the positive electrode of the bearing voltage output is connected with the rotating shaft through a conductive brush. Through the reliable contact of the pressing sheet, the conductive brush and the bearing inner and outer rings, it is ensured that the simulated bearing voltage can be stably output to the test bearing.

[0063] Compared with the bearing voltage generation mechanism, there is no C wg Parameter in the simulator, because C wg Parameter does not affect the bearing voltage waveform and bearing current size in the simulator. Therefore, the parasitic capacitance of the stator winding and the shell is not designed in the simulator.

[0064] Further, in the design of the bearing voltage simulation circuit, particular attention is paid to the steady-state solution of the output voltage. Therefore, the capacitance value is determined according to the principle of 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 sizes of the three-phase capacitance resistances are the same, so that formula (3) is obtained; according to the circuit principle, the voltage division ratio between U b and U o is calculated as shown in formula (4); since the bearing capacitance C b is relatively small, it can be ignored in the calculation process, so formula (5) is obtained; further combining formula (5) and formula (2), the relationship between the final bearing voltage output and U dc is obtained as 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 value of each capacitor element in the circuit can be adjusted, or the duty cycle of the MOS tube Q v can be adjusted in the software end to change the voltage gain, so as to achieve 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 needs and application scenarios.

[0066]

[0067] C1=C2=C3 (3)

[0068]

[0069]

[0070] In designing the high-pass filter, considering that the high-frequency circulating current equivalent oscillation frequency is in the range of 0.64MHz to 1.6MHz, the resistance R hfp and the selection of the capacitance C hfp are crucial. To ensure that the filter can work effectively in this frequency range, the parameter range given by formula (8) can be referred to for design. Such a design will help to ensure that the filter can accurately filter out low-frequency noise while allowing high-frequency circulating bearing voltage to pass through.

[0071]

[0072] In this embodiment, the capacitances C4 and C5 are selected as high-voltage large-capacitance DC bus support capacitors. This selection helps to ensure the stability and reliability of the circuit, especially when dealing with high-voltage applications. To maintain the neutral point potential between C4 and C5 constant, we have connected a voltage-sharing resistor in parallel across C4 and C5. This design strategy is crucial because it guarantees the upper and lower symmetry of the output bearing voltage waveform, avoiding the problem of potential drift. Through this design, this embodiment can provide stable and symmetrical bearing voltage output, which is crucial for accurate simulation and research of motor bearing electric corrosion phenomena, further improving the accuracy and reliability of the simulation results.

[0073] Example 1:

[0074] When simulating the bearing voltage of an actual motor, the bearing voltage is small and basically constant. To achieve 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 three-phase bridge inverter circuit are removed from the bearing voltage simulator, and the output end of the actual motor controller is 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, thereby obtaining the same bearing voltage as the actual motor.

[0075] Example 2:

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

[0077] Those skilled in the art can understand that the above description is only the preferred embodiment of the present application, and the features described in various embodiments of the present disclosure and / or claims can be combined or combined, even if such combination or combination is not explicitly described in the present disclosure. It is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacement for part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0078] Although preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application. Obviously, those skilled in the art can make various modifications and changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and changes of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and changes.

Claims

1. An electric motor bearing voltage simulation apparatus for bearing electrochemical corrosion testing, characterized by, The motor bearing voltage simulation device comprises a BUCK voltage regulating circuit (1), a three-bridge-arm inverter (2), a common-mode voltage output loop (3), a high-pass filter loop (4), a bearing voltage simulation loop (5), and a bearing voltage output loop (6). The positive pole of the DC power source is connected to one side of the switch MOS tube Qv in the BUCK voltage regulating circuit (1), the positive pole of the diode D1 is connected to the negative pole of the DC power source, and the negative pole of the diode D1 is connected to the other side of the switch MOS tube Qv. The switch MOS tube Qv is 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 pole of the DC power source, and the connection point of the capacitor C4 and the capacitor C5 is led out to obtain the negative pole of the bearing voltage output end. The upper end of the capacitor C4 is connected to the upper end of the three-bridge-arm inverter (2), and the lower end of the capacitor C5 is connected to the lower end of the three-bridge-arm inverter (2); the three-phase output ends are respectively connected to one side of three resistors R1, R2 and R3 of the common-mode voltage output loop (3). The other side of the three resistors R1, R2 and R3 in the common-mode voltage output loop (3) is respectively connected to the left side of three capacitors C1, C2 and C3, and the other side of the capacitors C1, C2 and C3 is connected to the common-mode voltage output end. The capacitor C in the high-pass filter circuit (4) hfp One side is connected to the common-mode voltage output terminal, and capacitor C hfp The other end is connected to the upper end of relay K2, while capacitor C... hfp The two ends of relay K1 are connected to the two ends of relay K2 respectively; the lower end of relay K2 is connected to resistor R. hfp At the upper end, resistor R hfp The lower end is connected to the negative terminal of the bearing voltage output terminal; In the bearing voltage analog circuit (5), one side of the capacitor C wr connects the right end of the relay K1, the other end of the capacitor C wr connects the positive pole of the bearing voltage output end; the upper and lower ends of the capacitor C rs connect respectively 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 apparatus for bearing electrochemical test according to claim 1, characterized in that, Each phase in the common-mode voltage output loop (3) is a resistor-capacitor series structure, and the output end point is a common connection point on one side of the three-phase capacitors, which is used to obtain the common-mode voltage.

3. The motor bearing voltage simulation apparatus for bearing electrochemical test according to claim 2, characterized in that, The sizes of the three-phase resistor-capacitors in the common-mode voltage output loop (3) are the same.

4. The motor bearing voltage simulation apparatus for bearing electrochemical 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 apparatus for bearing electrochemical test according to claim 1, characterized in that, The bearing voltage analog loop (5) also comprises a design capacitor C rs The parameter is a capacitor C ws The parameter is a capacitor C 6. The motor bearing voltage simulation apparatus for bearing electrochemical test according to claim 1, characterized in that, The bearing voltage output loop (6) is connected by pressing the negative pole of the bearing voltage output end and the positive pole of the bearing voltage output end through the conductive brush and the rotating shaft.

7. The motor bearing voltage simulation apparatus for bearing electrochemical test according to claim 1, characterized by, The voltage equalizing resistor is also connected in parallel between the capacitor C4 and the capacitor C5.

8. A method for motor bearing voltage simulation for bearing electrochemical corrosion test, characterized in that, The motor bearing voltage simulation method is realized by using the device of any one of claims 1 to 7, and the method comprises the following steps: The two kinds of bearing voltages generated on the bearing are connected to the output terminals of the device, and the two kinds of bearing voltages are applied to the bearing, so as to complete the motor bearing voltage simulation of the bearing corrosion test.

9. The motor bearing voltage simulation method for bearing electrochemical test according to claim 8, characterized in that, The two kinds of bearing voltages include a bearing voltage with the same shape as the common-mode voltage and a high-frequency shaft voltage with a sharp peak.

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