Bearing voltage simulator for electric corrosion test of motor bearing and operation method

Abstract

The invention discloses a bearing voltage simulator for a motor bearing electro-corrosion test and an operation method, belongs to the technical field of motor bearing electro-corrosion, and solves the problems that the measurement precision is interfered by stray parameters, the bearing voltage is difficult to flexibly adjust, a motor test platform is complex to operate and low in efficiency, and the test cost is high in the prior art in a bearing electro-corrosion experiment method. And the deep research of the bearing electro-corrosion mechanism is restricted. The invention provides a bearing voltage simulator for a motor bearing electrocorrosion test, which is formed by sequentially and electrically connecting a Boost voltage regulating circuit, a three-phase bridge type inverter circuit and a bearing voltage high-frequency model, and can accurately reproduce the voltage waveform of a motor bearing through a specific operation method, realize on-line adjustability of parameters and assist in bearing electrocorrosion research. According to the invention, the voltage waveform of the motor bearing can be accurately reproduced, parameters are adjustable on line, and the electric stress of the bearing under different working conditions can be flexibly simulated. A reliable platform is provided for bearing electrocorrosion research, and research cost and experiment complexity are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical corrosion of motor bearings, and particularly to a bearing voltage simulator and an operation method for electrical corrosion testing of motor bearings. Background Art

[0002] During the operation of an electric drive system, the bearing is one of the components with a high failure rate, and its performance degradation rate directly affects the overall life of the system. Research shows that bearing electrical corrosion is one of the main reasons for the damage of motor bearings. In a speed control system driven by a PWM inverter, the common-mode voltage will form an induced voltage across the bearings through the coupling effect of the parasitic capacitance inside the motor. Once this voltage exceeds the insulation threshold of the grease film, it will cause the breakdown of the oil film and generate a discharge current (EDM current). The high energy released during the discharge process will not only form micropits on the surfaces of the bearing raceway and rolling elements, but also accelerate the oxidation and failure of the grease. Long-term electrical corrosion will cause large-area damage to the bearing working surface, significantly reduce the lubrication performance, and ultimately greatly shorten the bearing service life.

[0003] The amplitude, frequency, and action time of the bearing current are the key parameters determining the degree of electrical corrosion, but the existing bearing electrical corrosion experimental methods have significant limitations. In a traditional motor test platform, measuring the bearing current requires modifying the motor structure. For example, an insulating layer is installed on the outer ring of the bearing and connected to the machine shell through an external wire, and then a current probe is used to measure the wire current. However, this modification will introduce stray parameter interference and affect the measurement accuracy. In addition, the amplitude of the bearing voltage (V b ) mainly depends on the modulation strategy of the inverter and the DC bus voltage (V dc ). Once the motor system is determined, V b is difficult to adjust flexibly. This inherent characteristic makes it impossible for experimenters to actively adjust the electrical stress level, restricting the feasibility of the electrical corrosion acceleration experiment. More critically, the motor test platform is complex and inefficient in terms of bearing replacement, current monitoring, and fault diagnosis. For example, frequent disassembly and assembly of the bearing may introduce mechanical damage and interfere with the experimental results, while the on-line monitoring technology is limited by space and signal noise problems. These factors jointly restrict the in-depth study of the bearing electrical corrosion mechanism, and there is an urgent need to develop more flexible and controllable experimental methods to support related theoretical exploration.

[0004] The bearing current problem can be considered from two aspects: the voltage source and the bearing impedance. The common-mode voltage V cm output by the motor controller forms a voltage source across the inner and outer rings of the bearing after being coupled by the motor parasitic capacitance, and the bearing impedance changes with the working conditions. When the voltage source forms a loop, the bearing current is generated. Based on this, the concept of the open-circuit bearing voltage V b_o is proposed, which is defined as the measured voltage of the rotating shaft to the machine shell when completely insulated ceramic ball bearings are installed at both ends of the motor. When V dcAfter determination, V cm With a fixed amplitude, when the parameters of the motor (equipped with ceramic ball bearings at both ends) are determined, V b_o is also constant. Due to the insulation of the ceramic ball bearings, V b_o is not affected by the bearing impedance state, rotational speed, applied force and other operating conditions.

[0005] Therefore, V b_o can be directly used as the output reference of the Bearing Voltage Simulator (BVS), avoiding complex bearing impedance modeling. Only need to develop a BVS that can accurately reproduce V b_o , apply its output voltage to the test bearing (the same model), and then simulate the actual operating conditions to obtain the bearing voltage V b and current i b consistent with the actual motor, so as to carry out the electro - corrosion experiment. Summary of the Invention

[0006] The present invention proposes a bearing voltage simulator and an operation method for electro - corrosion testing of motor bearings. By constructing a circuit structure including a Boost voltage regulating circuit, a three - phase bridge inverter circuit, and a Bearing Voltage High - Frequency Model (BVHM), the Boost voltage regulating circuit is used to adjust the DC power supply voltage. The three - phase bridge inverter circuit uses the SVPWM modulation method to output a common - mode voltage with a specific waveform, and then combines with the BVHM to simulate the high - frequency common - mode impedance characteristics of the motor, realizing the accurate reproduction and flexible adjustment of the open - circuit bearing voltage V b_o . Apply its output voltage to the test bearing and simulate the actual operating conditions, solving the problems in the existing bearing electro - corrosion experiment methods, such as the measurement accuracy being interfered by stray parameters, the bearing voltage being difficult to flexibly adjust, the operation of the motor test platform being complex and inefficient, which restricts the in - depth study of the bearing electro - corrosion mechanism.

[0007] A bearing voltage simulator for electro - corrosion testing of motor bearings, the bearing voltage simulator for electro - corrosion testing of motor bearings includes a Boost voltage regulating circuit, a three - phase bridge inverter circuit, and a bearing voltage high - frequency model. The Boost voltage regulating circuit, the three - phase bridge inverter circuit, and the bearing voltage high - frequency model are electrically connected in sequence.

[0008] Further, the Boost voltage regulating circuit is used to adjust the input voltage;

[0009] The three - phase bridge inverter circuit is used to generate a common - mode voltage;

[0010] The bearing voltage high - frequency model is used to simulate the high - frequency common - mode impedance characteristics of the motor.

[0011] Further, in the Boost voltage regulating circuit, it includes a DC power supply, an inductor L0, a switching transistor M0, a diode D0, a capacitor C1, and a capacitor C2. The positive pole of the DC power supply is connected to one side of the inductor L0. One end of the switching transistor M0 is connected to the negative pole of the DC power supply, and the other end of the switching transistor M0 is connected to the other side of the inductor L0. The inductor L0 is simultaneously connected to the positive pole of the diode D0. The negative pole of the diode D0 is connected to the upper end of the capacitor C1. The lower end of the capacitor C1 is connected to the upper end of the capacitor C2. The lower end of the capacitor C2 is connected to the negative pole of the DC power supply. The negative output terminal of the bearing voltage high-frequency model is led out from the connection point O of the capacitor C1 and the capacitor C2.

[0012] Further, the three-phase bridge inverter circuit includes a first bridge arm, a second bridge arm, and a third bridge arm.

[0013] The first bridge arm includes M1 and M2. M1 and M2 are connected in series, and the midpoint of the bridge arm is point a. Point a is connected to one end of the Model_A circuit module.

[0014] The second bridge arm includes M3 and M4. M3 and M4 are connected in series, and the midpoint of the bridge arm is point b. Point b is connected to one end of the Model_B circuit module.

[0015] The third bridge arm includes M5 and M6. M5 and M6 are connected in series, and the midpoint of the bridge arm is point c. Point c is connected to one end of the Model_C circuit module.

[0016] Both ends of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the negative pole of the diode D0 and the negative pole of the DC power supply.

[0017] Further, the bearing voltage high-frequency model includes a Model_A circuit module, a Model_B circuit module, a Model_C circuit module, and a capacitor C rg , the first ends of the Model_A circuit module, the Model_B circuit module, and the Model_C circuit module are respectively connected to point a, point b, and point c in the three-phase bridge inverter circuit through windings w, the second ends are respectively connected to the negative output terminal of the bearing voltage high-frequency model through the machine housing g, and the third ends are respectively connected to the positive output terminal of the bearing voltage high-frequency model through the rotor r. The upper and lower ends of the capacitor C rg are respectively connected to the positive and negative poles of the output terminal of the bearing voltage high-frequency model.

[0018] Further, the Model_A circuit module, the Model_B circuit module, and the Model_C circuit module all include: a capacitor C wr1 , a capacitor C wr2 , a capacitor C wg1 , a capacitor C wg2 , a resistor R wg1 , a resistor R wg2 , an inductor L cmand resistor R e and capacitor C wr1 One end of is connected to one end of capacitor C wg1 and the other end is connected to one end of capacitor C wr2 The other end of capacitor C wr2 is connected to one end of capacitor C wg2 The other end of capacitor C wg2 is connected to one end of resistor R wg2 The other end of resistor R wg2 is connected to one end of resistor R wg1 The other end of resistor R wg1 is connected to the other end of capacitor C wg1 Inductor L cm and resistor R e One end of is connected to one end of capacitor C wr1 Inductor L cm and resistor R e The other end is connected to the other end of capacitor C wr2 are connected together.

[0019] Furthermore, in the Model_A circuit module, Model_B circuit module and Model_C circuit module, the common end of capacitor C wr1 and capacitor C wg1 is the first end, the common end of resistor R wg1 and resistor R wg2 is the second end, and the common end of capacitor C wr1 and capacitor C wr2 is the third end.

[0020] A running method of a bearing voltage simulator for motor bearing electro-corrosion test, which is applied to the above-mentioned bearing voltage simulator for motor bearing electro-corrosion test, and the running method includes the following steps:

[0021] S1. According to the C wr_total of the motor to be simulated, calculate the open-circuit bearing voltage voltage division ratio through formula (2):

[0022]

[0023] where C wr_total is the total parasitic capacitance of winding w to rotor r, C rg is the parasitic capacitance of rotor w to the machine housing g, V b_o is the target open-circuit bearing voltage, V cm is the common-mode voltage output by the motor controller, V b_o is the simulator output voltage;

[0024] S2. According to the Boost voltage regulating circuit, set the boost ratio H through formula (3):

[0025]

[0026] Among them, d is the duty cycle of the driving signal of the Boost circuit switching transistor M0. By adjusting the duty cycle d of the driving signal of the switching transistor M0, the output voltage is boosted to:

[0027] V mn = H·V in

[0028] Among them, V in is the input DC voltage of the BVS;

[0029] S3. Adopt the SVPWM modulation method, and the output V cm0 is a four-level stepped wave:

[0030]

[0031] Set the switching frequency and modulation ratio through the host computer to control the switching timing of M1 - M6;

[0032] S4. Impedance-match the output of the inverter through the BVHM circuit module to obtain the simulator output voltage V b_o with respect to V cm0 transfer function to achieve voltage conversion:

[0033]

[0034] Among them,

[0035]

[0036] S5. Real-time control the output voltage according to formula (8):

[0037]

[0038] According to formula (8), when V in and the simulator BVHM circuit parameters are determined, the magnitude of V b_o is only related to the duty cycle d. The host computer software flexibly adjusts the magnitude of the output V o by adjusting the coefficient K b_o .

[0039] A storage medium stores a computer program thereon. When the computer program is executed by a processor, it implements the above-mentioned operation method of the bearing voltage simulator for motor bearing electro-corrosion testing.

[0040] A computer device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the program to implement the above-mentioned operation method of the bearing voltage simulator for electric corrosion testing of motor bearings.

[0041] Advantages of the present invention:

[0042] 1. The present invention proposes a bearing voltage simulator (BVS) for motor bearings, which can accurately reproduce the voltage waveform characteristics of actual motor bearings (including key parameters such as amplitude, frequency, modulation ratio, etc.), and the parameters can be adjusted online through a host computer. This simulator can not only flexibly simulate the bearing electrical stress under different working conditions, but also provide a reliable experimental platform for the research of bearing electrical corrosion mechanism and life prediction.

[0043] 2. The bearing voltage simulator (BVS) of the present invention has the characteristics of adjustable parameters and high waveform reproduction accuracy, can effectively replace the actual motor for bearing electrical stress experiments, and significantly reduce the research cost and experimental complexity. Description of the drawings

[0044] Figure 1 Schematic diagram of the ideal bearing voltage waveform;

[0045] Figure 2 Main circuit structure of a bearing voltage simulator for electric corrosion testing of motor bearings according to the present invention;

[0046] Figure 3 Circuit structure of the Model_A circuit module, Model_B circuit module or Model_C circuit module in BVHM;

[0047] Figure 4 Schematic diagram of the key waveform. Detailed implementation manners

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] Refer to Figures 1-4 As shown, a bearing voltage simulator for electric corrosion testing of motor bearings, the bearing voltage simulator for electric corrosion testing of motor bearings includes a Boost voltage regulating circuit, a three-phase bridge inverter circuit, and a bearing voltage high-frequency model. The Boost voltage regulating circuit, the three-phase bridge inverter circuit, and the bearing voltage high-frequency model are electrically connected in sequence.

[0050] Specifically, the bearing voltage simulator for motor bearing electro - corrosion testing of the present invention is composed of a Boost voltage - regulating circuit, a three - phase bridge inverter circuit, and a bearing voltage high - frequency model, which are electrically connected in sequence. When conducting bearing electro - corrosion experiments on traditional motor test platforms, there are many problems. Measuring the bearing current requires modifying the motor structure, which not only introduces stray parameters to interfere with the measurement accuracy but also makes the operation of the motor test platform complex and inefficient in terms of bearing replacement, current monitoring, and fault diagnosis. At the same time, it is difficult to flexibly adjust the bearing voltage, which severely restricts the development of electro - corrosion acceleration experiments. The core advantage of the bearing voltage simulator for motor bearing electro - corrosion testing proposed by the present invention is that it adjusts the input voltage through the Boost voltage - regulating circuit to provide a stable and adjustable power supply basis for the subsequent circuit operation. The three - phase bridge inverter circuit generates a common - mode voltage. Combining a specific SVPWM modulation method, it can output a common - mode voltage with a specific waveform, which is crucial for simulating the voltage environment under the actual motor operating conditions. The bearing voltage high - frequency model simulates the high - frequency common - mode impedance characteristics of the motor. The three work together to achieve the accurate reproduction and flexible adjustment of the open - circuit bearing voltage V b_o The accurate reproduction and flexible adjustment of b_o are realized. This enables the simulator to accurately reproduce the voltage waveform characteristics of the actual motor bearing, including key parameters such as amplitude, frequency, modulation ratio, etc. By making the parameters adjustable online through the host computer, experimenters can flexibly simulate the bearing electrical stress under different working conditions, providing a reliable experimental platform for the study of bearing electro - corrosion mechanism and life prediction. Moreover, due to its characteristics of adjustable parameters and high waveform reproduction accuracy, it can effectively replace the actual motor for bearing electrical stress experiments, significantly reducing the research cost and experimental complexity.

[0051] Further, the Boost voltage - regulating circuit is used to adjust the input voltage;

[0052] The three - phase bridge inverter circuit is used to generate a common - mode voltage;

[0053] The bearing voltage high - frequency model is used to simulate the high - frequency common - mode impedance characteristics of the motor.

[0054] Specifically, this embodiment clarifies the specific functions of each circuit module in the bearing voltage simulator, that is, the Boost voltage - regulating circuit is used to adjust the input voltage, the three - phase bridge inverter circuit is used to generate a common - mode voltage, and the bearing voltage high - frequency model is used to simulate the high - frequency common - mode impedance characteristics of the motor. In the traditional motor bearing electro - corrosion experimental environment, since the amplitude of the bearing voltage V b mainly depends on the modulation strategy of the inverter and the DC bus voltage V dc , once the motor system is determined, V bIt is difficult to adjust flexibly. This limitation makes it impossible for experimenters to actively adjust the electrical stress level of the booklet, restricting the feasibility of the electrical corrosion acceleration experiment. In the present invention, the Boost voltage regulating circuit adjusts the input voltage, breaking the limitation of the DC bus voltage and providing a more flexible voltage input condition for the subsequent generation of the common-mode voltage. It is like the "power regulating valve" of the entire simulator, which can accurately adjust the magnitude of the input voltage according to the experimental requirements to ensure that the subsequent circuit modules can operate in a suitable voltage environment. After receiving the voltage adjusted by the Boost voltage regulating circuit, the three-phase bridge inverter circuit generates the common-mode voltage using the SVPWM modulation method. In this way, a stable and adjustable common-mode voltage can be output, accurately simulating the common-mode voltage waveform generated during the actual operation of the motor. This function is crucial for simulating the electrical stress under the actual operating conditions of the motor, providing a guarantee for applying accurate electrical stress to the subsequent test bearings. The high-frequency model of the bearing voltage simulates the high-frequency common-mode impedance characteristics of the motor and can accurately convert the common-mode voltage into a bearing voltage that conforms to the actual situation. It fully considers the influence of complex parasitic capacitances and other factors inside the motor on the voltage, making the voltage output by the simulator closer to the voltage borne by the actual motor bearing. This simulation of the high-frequency common-mode impedance characteristics effectively avoids the complex process of bearing impedance modeling and greatly simplifies the experimental operation.

[0055] Further, the Boost voltage regulating circuit includes a DC power supply, an inductor L0, a switching tube M0, a diode D0, a capacitor C1, and a capacitor C2. The positive pole of the DC power supply is connected to one side of the inductor L0. One end of the switching tube M0 is connected to the negative pole of the DC power supply, and the other end of the switching tube M0 is connected to the other side of the inductor L0. The inductor L0 is simultaneously connected to the positive pole of the diode D0. The negative pole of the diode D0 is connected to the upper end of the capacitor C1. The lower end of the capacitor C1 is connected to the upper end of the capacitor C2. The lower end of the capacitor C2 is connected to the negative pole of the DC power supply. The output terminal negative of the high-frequency model of the bearing voltage is led out from the connection point O of the capacitor C1 and the capacitor C2.

[0056] Further, the three-phase bridge inverter circuit includes a first bridge arm, a second bridge arm, and a third bridge arm.

[0057] The first bridge arm includes M1 and M2, which are connected in series. The midpoint of the bridge arm is point a, and point a is connected to one end of the Model_A circuit module.

[0058] The second bridge arm includes M3 and M4, which are connected in series. The midpoint of the bridge arm is point b, and point b is connected to one end of the Model_B circuit module.

[0059] The third bridge arm includes M5 and M6, which are connected in series. The midpoint of the bridge arm is point c, and point c is connected to one end of the Model_C circuit module.

[0060] Both ends of the first arm, the second arm, and the third arm are respectively connected to the negative electrode of diode D0 and the negative electrode of the DC power supply.

[0061] Specifically, in traditional motor bearing electro-corrosion experiments, it is difficult to flexibly adjust the bearing voltage, and it is impossible to accurately simulate the voltage waveform under actual working conditions, resulting in a significant reduction in the accuracy and reliability of the experimental results. The specific connection method of the three-phase bridge inverter circuit and each circuit module in the present invention effectively solves these problems. The three arms of the three-phase bridge inverter circuit are respectively connected to the Model_A, Model_B, and Model_C circuit modules. This connection enables the three-phase bridge inverter circuit to convert the DC power supply into a common-mode voltage with a specific waveform and then accurately transmit it to the corresponding circuit module in the bearing voltage high-frequency model BVHM. By controlling the switching sequence of the switching tubes M1-M6 on the arm and using the SVPWM modulation method, a stable four-level stepped wave common-mode voltage V can be output. cm0 . This stable and adjustable common-mode voltage provides reliable input conditions for subsequent simulation of the high-frequency common-mode impedance characteristics of the motor in BVHM. The connection of the Model_A, Model_B, and Model_C circuit modules to the three-phase bridge inverter circuit enables them to receive the common-mode voltage and simulate the complex electromagnetic environment inside the motor based on their own circuit structures and parameters. These circuit modules process the common-mode voltage through their respective combinations of capacitors, resistors, and inductors to more accurately simulate the high-frequency common-mode impedance characteristics of the motor. For example, the capacitors C wr1 , C wr2 , C wg1 , C wg2 , etc. can simulate the parasitic capacitance between the motor winding and the rotor and the casing, and the resistors R wg1 , R wg2 and the inductor L cm , etc. can simulate the corresponding impedance characteristics. Through this connection method, the entire simulator can simulate a voltage environment highly similar to that of an actual motor, enabling the output open-circuit bearing voltage V b_o to more accurately reproduce the voltage borne by the bearing of an actual motor during operation.

[0062] Furthermore, the bearing voltage high-frequency model includes a Model_A circuit module, a Model_B circuit module, a Model_C circuit module, and a capacitor C rg . The first ends of the Model_A circuit module, the Model_B circuit module, and the Model_C circuit module are respectively connected to points a, b, and c in the three-phase bridge inverter circuit through windings w, the second ends are respectively connected to the negative electrode of the output end of the bearing voltage high-frequency model through the casing g, and the third ends are respectively connected to the positive electrode of the output end of the bearing voltage high-frequency model through the rotor r. The capacitor C rgThe upper and lower ends are respectively connected to the positive and negative electrodes of the output end of the bearing voltage high-frequency model.

[0063] Specifically, the Model_A, Model_B, and Model_C circuit modules are respectively connected to points a, b, and c of the three-phase bridge inverter circuit. This connection enables the common-mode voltage to be smoothly input into each module. Their connections to the chassis g and the rotor r fully consider the actual electrical structure inside the motor. By connecting to the chassis g, the electrical relationship between the bearing and the chassis during motor operation is simulated; by connecting to the rotor r, the electromagnetic connection between the rotor and the bearing is reflected, which is crucial for accurately simulating the high-frequency common-mode impedance characteristics of the motor. Capacitor C rg is connected between the positive and negative electrodes of the output end of the bearing voltage high-frequency model. Its existence further optimizes the simulation effect of the high-frequency common-mode impedance characteristics of the motor. It can simulate the influence of the parasitic capacitance between the rotor and the chassis during motor operation, making the entire model more realistic in simulating the electrical environment during actual motor operation. In an actual motor, the parasitic capacitance between the rotor and the chassis will affect the distribution of the common-mode voltage across the bearing, and capacitor C rg 's setting enables the simulator to more accurately reflect this influence, thus making the output voltage closer to the voltage actually borne by the motor bearing. This structurally designed bearing voltage high-frequency model can accurately simulate the corresponding voltage characteristics according to the parameters and actual operating conditions of different motors. By adjusting the parameters of components such as capacitors, resistors, and inductors in each circuit module and combining the common-mode voltage output by the three-phase bridge inverter circuit, the open-circuit bearing voltage V b_o is accurately reproduced and flexibly adjusted.

[0064] Furthermore, each of the Model_A circuit module, Model_B circuit module, and Model_C circuit module includes: capacitor C wr1 、capacitor C wr2 、capacitor C wg1 、capacitor C wg2 、resistor R wg1 、resistor R wg2 、inductor L cm and resistor R e 、One end of capacitor C wr1 is connected to one end of capacitor C wg1 , and the other end is connected to one end of capacitor C wr2 . The other end of capacitor C wr2 is connected to one end of capacitor C wg2 . The other end of capacitor C wg2 is connected to one end of resistor R wg2 . The other end of resistor R wg2 is connected to one end of resistor R wg1 . The other end of resistor R wg1The other end is connected to capacitor C wg1 The other end of the inductor L cm and resistor R e One end of the capacitor C wr1 One end of the inductor L cm and resistor R e The other end is connected to the other end of the capacitor C wr2 They are connected to each other.

[0065] Specifically, in the field of research on electric corrosion of motor bearings, the high-frequency common-mode impedance characteristics during motor operation are complex and difficult to accurately simulate, which has always been an important factor restricting the research progress. In the present invention, the unique internal structure design of the Model_A, Model_B, and Model_C circuit modules effectively solves this problem. In each circuit module, capacitors C wr1 、C wr2 、C wg1 、C wg2 are interconnected to simulate the complex parasitic capacitance relationship between the motor winding and the rotor and the motor housing. During motor operation, these parasitic capacitances will affect the distribution of the common-mode voltage inside the motor, and further affect the bearing voltage. Through the reasonable setting of these capacitors in the present invention, the capacitance coupling effect in the actual motor can be accurately reproduced, so that the voltage output by the simulator can truly reflect the voltage change situation inside the motor. Resistors R wg1 、R wg2 and the inductor L cm and resistor R e combination further simulates the impedance characteristics inside the motor. The resistor simulates the resistance loss in the circuit, and the inductor takes into account the inductance effect generated by electromagnetic induction. Their combined action enables the circuit module to more accurately simulate the impedance change of the motor at high frequencies. This accurate simulation of the impedance characteristics is crucial for studying the variation law of current during the bearing electric corrosion process. Because the degree of bearing electric corrosion is closely related to the amplitude, frequency, and action time of the current, accurately simulating the impedance characteristics helps researchers better master the variation of current under different working conditions, so as to deeply explore the electric corrosion mechanism. The cooperation of each component enables these circuit modules to accurately simulate the high-frequency common-mode impedance characteristics of the motor under different operating conditions according to the common-mode voltage output by the three-phase bridge inverter circuit. This not only provides a solid foundation for accurately reproducing the open-circuit bearing voltage V b_o but also enables experimenters to flexibly simulate the bearing electrical stress under different motors and different working conditions by adjusting the component parameters in the circuit module. This greatly enhances the versatility and adaptability of the simulator. Whether for different types of motors or under different operating conditions, it can provide reliable experimental data support for the research on bearing electric corrosion. It effectively reduces the research cost and experimental complexity, and promotes the research on electric corrosion of motor bearings from theory to practical application.

[0066] Further, in the Model_A circuit module, Model_B circuit module, and Model_C circuit module, capacitor C wr1 and capacitor C wg1 have a common terminal as the first terminal, resistor R wg1 and resistor R wg2 have a common terminal as the second terminal, and capacitor C wr1 and capacitor C wr2 have a common terminal as the third terminal.

[0067] Specifically, the common terminal of capacitor C wr1 and capacitor C wg1 is used as the first terminal. Its significance lies in clearly identifying the parasitic capacitance associated part between the winding, rotor, and casing. During the operation of the motor, the interaction of these parasitic capacitances affects the distribution and transmission of the common-mode voltage. Determining this common terminal clarifies the key node for simulating this complex capacitance coupling relationship, enabling the simulator to more accurately reflect the electrical characteristics inside the motor and laying a foundation for accurately simulating the bearing voltage subsequently. The common terminal of resistor R wg1 and resistor R wg2 is used as the second terminal. This setting focuses on simulating the influence of the internal resistance characteristics of the motor on the circuit. Resistors play a role in obstructing current and consuming electrical energy in the circuit, and the internal resistance distribution and changes in the motor also affect the magnitude and characteristics of the bearing voltage and current. Defining this common terminal helps to accurately simulate the effect of the internal resistance network of the motor on the common-mode voltage, making the voltage and current output by the simulator more in line with the actual situation and providing an accurate basis for studying the energy loss and current change law during the bearing electro-corrosion process. The common terminal of capacitor C wr1 and capacitor C wr2 is used as the third terminal. Its importance is reflected in the deepening of the simulation of the high-frequency characteristics of the motor. The determination of this common terminal further refines the simulation of the parasitic capacitance relationship between the winding and the rotor, taking into account the specific connection points of the interaction between different capacitors, making the simulator more accurate when simulating the high-frequency common-mode impedance characteristics of the motor. In the high-frequency case, the change in the capacitive reactance of the capacitor has a significant impact on the circuit. Accurately grasping the characteristics of this common terminal can better simulate the fluctuation and change of the bearing voltage when the motor operates at high frequency, providing key support for studying the bearing electro-corrosion phenomenon under high-frequency conditions.

[0068] An operating method for a bearing voltage simulator used for motor bearing electro-corrosion testing, which is applied to the above-mentioned bearing voltage simulator for motor bearing electro-corrosion testing. The operating method includes the following steps:

[0069] S1. According to the C wr_total of the motor to be simulated, calculate the open-circuit bearing voltage division ratio through formula (2):

[0070]

[0071] Among them, C wr_total is the total parasitic capacitance of the winding w to the rotor r, and C rg is the parasitic capacitance of the rotor w to the machine housing g, V b_o is the target open-circuit bearing voltage, and V cm is the common-mode voltage output by the motor controller, and V b_o is the simulator output voltage;

[0072] S2. According to the Boost voltage regulating circuit, set the boost ratio H through formula (3):

[0073]

[0074] Among them, d is the duty cycle of the drive signal of the Boost circuit switch tube M0. Adjust the duty cycle d of the drive signal of the switch tube M0 to boost the output voltage to:

[0075] V mn = H·V in

[0076] Among them, V in is the input DC voltage of the BVS;

[0077] S3. Adopt the SVPWM modulation method to output V cm0 as a four-level stepped wave:

[0078]

[0079] Set the switching frequency and modulation ratio through the host computer to control the switching timing of M1 - M6;

[0080] S4. Impedance match the output of the inverter through the BVHM circuit module to obtain the transfer function of the simulator output voltage V b_o relative to V cm0 to achieve voltage conversion:

[0081]

[0082] Among them,

[0083]

[0084] S5. Control the output voltage in real time according to formula (8):

[0085]

[0086] According to formula (8), when V in and the simulator BVHM circuit parameters are determined, V b_oThe magnitude is only related to the duty cycle d, and the host computer software adjusts the coefficient K o , and flexibly adjusts the output V b_o magnitude.

[0087] Specifically, the present invention proposes a motor bearing voltage simulator. The circuit structure of the proposed motor bearing voltage simulator includes: a Boost voltage regulating circuit, a three-phase bridge inverter circuit, and a bearing voltage high-frequency model (BVHM). In order to accurately simulate the bearing voltage, the BVS needs to be able to describe the high-frequency common-mode impedance characteristics of the motor.

[0088] C wg_total represents the total parasitic capacitance of the winding ( Figure 2 at the w point in Figure 2 ) with respect to the machine case ( wr_total at the g point in Figure 2 ), C rg represents the total parasitic capacitance of the winding with respect to the rotor (

[0089] at the r point in cm ), and C dc represents the parasitic capacitance of the rotor with respect to the machine case. b The magnitude of V cm depends on the modulation method of the controller and V BVR . The relationship between V b and V b can be obtained as shown in Equation (1). K

[0090] is defined as the motor bearing voltage division ratio. When the motor parameters are determined, the magnitude of V dc is basically determined, and it is impossible to flexibly adjust V cm to meet the requirements of the bearing electro-corrosion acceleration test. b_o When the motor drive system V b_o is determined, the amplitude of V

[0091]

[0092] is determined. When the parameters of the motor (installed with ceramic ball bearings at both ends) are determined, the magnitude of V BVRo is also determined. Due to the insulation effect of the ceramic ball bearings, it can be considered that V

[0093] is not affected by the bearing impedance state, rotational speed, force and other working conditions. According to Equation (1), in The input DC voltage V mn of the BVS can be adjusted by the Boost circuit to adjust the output voltage V cm0 magnitude. The three-phase inverter circuit adopts the SVPWM modulation method, and the output Vmn By changing V mn Adjust V cm0 size, thus changing the BVS output voltage V b_o Size. V b_o The switching frequency of M1~M6 can be controlled by modifying the switching frequency of V b_o The pulse width can be achieved by changing the modulation ratio of the control algorithm.

[0094] According to the Boost voltage regulation circuit, the boost ratio H can be obtained from formula (3), and d is the duty cycle of the driving signal of the Boost circuit switch tube M0. Figure 2 The common mode voltage V output by the three-phase inverter circuit cm0 As shown in formula (4), the simulator output voltage V b_o Relative to V cm0 The transfer function is shown in equations (5) to (7), and the output voltage regulation coefficient K of the simulator is further obtained. o As shown in formula (8). According to formula (8), when V in After the circuit parameters of the simulator BVHM are determined, V b_o The size is only related to the duty cycle d. The upper computer software adjusts the coefficient K o , flexibly adjust the output V b_o size.

[0095] The operating method of the present invention firstly calculates the C of the simulated motor. wr_total The open-circuit bearing voltage divider ratio is calculated. This calculation provides a key reference for subsequent simulations, so that the voltage output by the simulator can be closer to the voltage borne by the actual motor bearing, avoiding experimental errors caused by inaccurate voltage simulation. Then, the boost ratio is set by using the Boost voltage regulation circuit, and the output voltage is increased by adjusting the duty cycle of the drive signal of the switch tube M0. This precise voltage regulation method breaks through the limitation that the bearing voltage is difficult to flexibly adjust in traditional tests. Experimenters can flexibly adjust the input voltage according to different experimental requirements, thereby simulating the bearing electrical stress under various working conditions, which provides the possibility for studying the influence of different electrical stress levels on bearing electrical corrosion. The SVPWM modulation method is used to output the common-mode voltage of the four-level step wave, and the switching frequency and modulation ratio are set by the host computer to control the switching timing of M1-M6. This process can accurately simulate the common-mode voltage waveform generated during the actual motor operation. Accurate common-mode voltage waveform simulation is crucial for studying bearing electrical corrosion, because common-mode voltage is one of the key factors that cause bearing electrical corrosion. Accurate simulation of its waveform helps to more realistically reproduce the environment in which electrical corrosion occurs. The inverter output is impedance matched through the BVHM circuit module to obtain the simulator output voltage V b_o Relative to V cm0The transfer function is used to achieve voltage conversion. This step gives full play to the role of the high-frequency model of the bearing voltage, takes into account the high-frequency common-mode impedance characteristics of the motor, and further improves the accuracy of simulation. In this way, the simulator can output a voltage signal highly similar to the actual motor bearing voltage, providing reliable data support for studying the voltage change law during the bearing electro-corrosion process. Finally, the output voltage is controlled in real time according to the formula, and the host computer software adjusts the coefficient K o flexibly adjusts the output V b_o magnitude, realizing real-time and precise control of the output voltage of the simulator. The experimenter can adjust the output voltage at any time according to the experimental progress and research needs, greatly enhancing the flexibility and controllability of the experiment. The operation method of this embodiment precisely reproduces the voltage waveform characteristics of the actual motor bearing through the close cooperation of each step, realizes online adjustable parameters, and provides a reliable experimental platform for the study of the bearing electro-corrosion mechanism and life prediction.

[0096] A storage medium stores a computer program thereon, and when the computer program is executed by a processor, it realizes the above-mentioned operation method of the bearing voltage simulator for motor bearing electro-corrosion testing.

[0097] Specifically, the storage medium proposed in this embodiment stores a computer program that can implement the operation method of the bearing voltage simulator. In the field of motor bearing electro-corrosion testing, the traditional experimental operation process is cumbersome, relying on manual adjustment and recording, which not only has low efficiency but also is prone to human errors, seriously affecting the accuracy and repeatability of the experiment. The computer program stored in the storage medium of the present invention has completely changed this situation. It solidifies the complex operation method of the bearing voltage simulator for motor bearing electro-corrosion testing in the form of program code, making the operation of the entire simulator highly automated and standardized. When the computer program is executed by a processor, it can accurately calculate the open-circuit bearing voltage division ratio according to the parameters of the simulated motor, adjust the boost ratio of the Boost voltage regulation circuit, control the three-phase bridge inverter circuit to output a specific common-mode voltage waveform, and achieve precise control of the high-frequency model of the bearing voltage, and finally adjust the output voltage of the simulator in real time. This means that regardless of the experimental environment, as long as there are corresponding hardware devices to read this storage medium and execute the program, the entire simulation process can be stably and accurately reproduced, avoiding experimental result deviations caused by differences in manual operations. This automated operation method greatly improves the experimental efficiency. Researchers no longer need to spend a lot of time and energy on cumbersome manual operations and parameter adjustments, but only need to focus on the analysis of experimental results and the exploration of research directions. At the same time, due to the consistency of program execution, different experimenters can obtain highly consistent experimental data when conducting the same experiment at different times, enhancing the repeatability and reliability of the experiment. In addition, the existence of the storage medium also facilitates the dissemination and application of the technology. The R & D team can use the storage medium as a carrier to quickly promote the technical solution of the present invention to different research institutions and enterprises. Relevant personnel only need to connect the storage medium to a suitable computer device to use the simulator for motor bearing electro-corrosion testing, reducing the threshold of technology application, accelerating the popularization of new technologies in the industry, and promoting the development of the entire motor bearing electro-corrosion research field towards a more efficient and accurate direction.

[0098] A computer device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the program to implement the above-mentioned operation method of the bearing voltage simulator for motor bearing electro-corrosion testing.

[0099] Specifically, the computer device involved in this embodiment integrates a memory, a processor, and a runnable computer program, and is specifically used to implement the operation method of the bearing voltage simulator. This design provides complete, efficient, and stable hardware support for the electrical corrosion test of motor bearings, strengthening the core technical advantages of the present invention from the practical application level. In the traditional electrical corrosion experiment environment of motor bearings, due to the lack of dedicated and integrated hardware devices, the experimental operation is complex and vulnerable to various factors. For example, the compatibility issues between different experimental devices, the error accumulation during manual operation, etc., all make it difficult to guarantee the accuracy and reliability of the experimental results, seriously restricting the in-depth study of the electrical corrosion mechanism of bearings. The computer device of the present invention fundamentally solves these problems. Its memory is used to store the computer program for implementing the operation method of the bearing voltage simulator, which not only ensures the integrity and stability of the operation method, but also facilitates calling and execution at any time. Whether it is the parameter calculation during the experiment, such as calculating the open-circuit bearing voltage division ratio according to the C of the simulated motor, or the instructions for controlling the coordinated operation of the Boost voltage regulation circuit, the three-phase bridge inverter circuit, and the bearing voltage high-frequency model, they can all be stored in the memory in an orderly manner to ensure the orderly progress of the entire simulation process. The processor, as the core operation unit, is responsible for quickly and accurately executing the computer program. It processes various data and instructions efficiently according to the logic set by the program. When adjusting the boost ratio of the Boost voltage regulation circuit, the processor quickly calculates the duty cycle of the drive signal of the switch tube M0 according to the input DC voltage and the target output voltage; when controlling the three-phase bridge inverter circuit, it accurately sets the switching frequency and modulation ratio to output a four-level stepped wave common-mode voltage that meets the requirements. This fast and accurate computing power ensures that the simulator can simulate the electrical corrosion environment of motor bearings under different working conditions in real time and stably. By closely combining the memory, the processor, and the computer program, this computer device provides an integrated solution for the bearing voltage simulator. Researchers no longer need to spend a lot of time and effort integrating different devices and debugging complex circuit connections. They only need to operate this computer device to easily start and control the operation of the bearing voltage simulator. This greatly simplifies the experimental process, improves the experimental efficiency, and reduces the influence of human factors on the experimental results. At the same time, the stability and reliability of the device ensure that accurate simulation results can be continuously output during long-term and multi-batch experiments, providing a solid data basis for the research on the electrical corrosion mechanism and life prediction of bearings, and strongly promoting the technological progress and development in the field of electrical corrosion research of motor bearings. wr_total When calculating the open-circuit bearing voltage division ratio, or the instructions for controlling the coordinated operation of the Boost voltage regulation circuit, the three-phase bridge inverter circuit, and the bearing voltage high-frequency model, they can all be stored in the memory in an orderly manner to ensure the orderly progress of the entire simulation process. The processor, as the core operation unit, is responsible for quickly and accurately executing the computer program. It processes various data and instructions efficiently according to the logic set by the program. When adjusting the boost ratio of the Boost voltage regulation circuit, the processor quickly calculates the duty cycle of the drive signal of the switch tube M0 according to the input DC voltage and the target output voltage; when controlling the three-phase bridge inverter circuit, it accurately sets the switching frequency and modulation ratio to output a four-level stepped wave common-mode voltage that meets the requirements. This fast and accurate computing power ensures that the simulator can simulate the electrical corrosion environment of motor bearings under different working conditions in real time and stably. By closely combining the memory, the processor, and the computer program, this computer device provides an integrated solution for the bearing voltage simulator. Researchers no longer need to spend a lot of time and effort integrating different devices and debugging complex circuit connections. They only need to operate this computer device to easily start and control the operation of the bearing voltage simulator. This greatly simplifies the experimental process, improves the experimental efficiency, and reduces the influence of human factors on the experimental results. At the same time, the stability and reliability of the device ensure that accurate simulation results can be continuously output during long-term and multi-batch experiments, providing a solid data basis for the research on the electrical corrosion mechanism and life prediction of bearings, and strongly promoting the technological progress and development in the field of electrical corrosion research of motor bearings.

[0100] The present invention has developed a bearing voltage simulator for electrical corrosion testing of motor bearings that can accurately describe V b_o and applies the output voltage to the inner and outer rings of the test bearing (using the same type of bearing as the motor). When the bearing operates according to the actual motor working conditions, the bearing voltage V same as that of the actual motor can be obtained.b and the bearing current i b , thereby conducting an electro-corrosion experiment.

[0101] 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 , in an actual motor, the jump time of the common-mode voltage varies according to the different positions of the SVPWM control sector in each cycle. By precisely controlling the switching states of the three-phase bridge inverter circuit, the present invention can simulate the same common-mode voltage waveform as that in an actual motor. A Boost voltage regulating circuit is connected to the back end of the DC power supply, which can achieve precise regulation of the DC power supply voltage, and further achieve adjustment of the amplitude of the bearing voltage.

[0102] In terms of bearing voltage output, the outer ring of the bearing is in reliable contact with the negative pole of the bearing voltage output terminal through a pressing piece, while the positive pole of the bearing voltage output is connected to the rotating shaft through a conducting brush. Through the reliable contact of the pressing piece, conducting brush with the inner and outer rings of the bearing, it is ensured that the simulated bearing voltage can be stably output to the test bearing.

[0103] The specific embodiments of the invention have been described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A bearing voltage simulator for electric corrosion testing of motor bearings, characterized in that, The bearing voltage simulator for electric corrosion test of motor bearings includes a Boost voltage regulating circuit, a three-phase bridge inverter circuit, and a bearing voltage high-frequency model. The Boost voltage regulating circuit, the three-phase bridge inverter circuit, and the bearing voltage high-frequency model are electrically connected in sequence.

2. The bearing voltage simulator for electric corrosion test of motor bearings according to claim 1, wherein the Boost voltage regulating circuit is used to regulate the input voltage; the three-phase bridge inverter circuit is used to generate a common-mode voltage; the bearing voltage high-frequency model is used to simulate the high-frequency common-mode impedance characteristics of the motor.

3. The bearing voltage simulator for electric corrosion test of motor bearings according to claim 2, characterized in that In the Boost voltage regulating circuit, it includes a DC power supply, an inductor L0, a switching tube M0, a diode D0, a capacitor C1, and a capacitor C2. The positive pole of the DC power supply is connected to one side of the inductor L0. One end of the switching tube M0 is connected to the negative pole of the DC power supply, and the other end of the switching tube M0 is connected to the other side of the inductor L0. The inductor L0 is simultaneously connected to the positive pole of the diode D0. The negative pole of the diode D0 is connected to the upper end of the capacitor C1. The lower end of the capacitor C1 is connected to the upper end of the capacitor C2. The lower end of the capacitor C2 is connected to the negative pole of the DC power supply. The output negative pole of the bearing voltage high-frequency model is led out from the connection point O of the capacitor C1 and the capacitor C2.

4. The bearing voltage simulator for electric corrosion test of motor bearings according to claim 3, characterized in that, The three-phase bridge inverter circuit includes a first bridge arm, a second bridge arm, and a third bridge arm. The first bridge arm includes M1 and M2. M1 and M2 are connected in series, and the midpoint of the bridge arm is point a. Point a is connected to one end of the Model_A circuit module. The second bridge arm includes M3 and M4. M3 and M4 are connected in series, and the midpoint of the bridge arm is point b. Point b is connected to one end of the Model_B circuit module. The third bridge arm includes M5 and M6. M5 and M6 are connected in series, and the midpoint of the bridge arm is point c. Point c is connected to one end of the Model_C circuit module. Both ends of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the negative pole of the diode D0 and the negative pole of the DC power supply.

5. The bearing voltage simulator for electric corrosion test of motor bearings according to claim 4, characterized in that, The described high-frequency model of bearing voltage includes Model_A circuit module, Model_B circuit module, Model_C circuit module and capacitor C rg , the first ends of Model_A circuit module, Model_B circuit module and Model_C circuit module are respectively connected to points a, b and c in the three-phase bridge inverter circuit through windings w, the second ends are respectively connected to the negative pole of the output end of the high-frequency model of bearing voltage through the machine housing g, and the third ends are respectively connected to the positive pole of the output end of the high-frequency model of bearing voltage through the rotor r. The upper and lower ends of capacitor C rg are respectively connected to the positive and negative poles of the output end of the high-frequency model of bearing voltage.

6. The bearing voltage simulator for electric corrosion test of motor bearings according to claim 5, characterized in that, The Model_A circuit module, Model_B circuit module, and Model_C circuit module all include: capacitor C wr1 , capacitor C wr2 , capacitor C wg1 , capacitor C wg2 , resistor R wg1 , resistor R wg2 , inductor L cm and resistor R e , capacitor C wr1 One end of capacitor C wg1 is connected to one end of capacitor C wr2 , and the other end is connected to one end of capacitor C wr2 . The other end of capacitor C wg2 is connected to one end of capacitor C wg2 . The other end of capacitor C wg2 is connected to one end of resistor R wg2 . The other end of resistor R wg1 is connected to one end of resistor R wg1 . The other end of resistor R wg1 is connected to the other end of capacitor C cm . Inductor L e and resistor R wr1 One end is connected to one end of capacitor C cm . Inductor L e and resistor R wr2 The other ends are connected to the other end of capacitor C 7. The bearing voltage simulator for the electro-corrosion test of the motor bearing according to claim 6, wherein In the Model_A circuit module, Model_B circuit module, and Model_C circuit module, capacitor C wr1 and capacitor C wg1 have a common terminal as the first terminal, resistor R wg1 and resistor R wg2 have a common terminal as the second terminal, capacitor C wr1 and capacitor C wr2 have a common terminal as the third terminal.

8. A running method of a bearing voltage simulator for electric corrosion test of motor bearings, applied to the bearing voltage simulator for electric corrosion test of motor bearings according to any one of claims 1-7, characterized in that, The operation method includes the following steps: S1. According to C of the motor to be simulated wr_total , calculate the open-circuit bearing voltage partial pressure ratio through formula (2): Among them, C wr_total is the total parasitic capacitance of winding w to rotor r, C rg is the parasitic capacitance of rotor w to the machine housing g, V b_o is the target open-circuit bearing voltage, V cm is the common-mode voltage output by the motor controller, V b_o is the simulator output voltage; S2. According to the Boost voltage regulating circuit, set the boost ratio H through formula (3): where d is the duty cycle of the drive signal of the Boost circuit switching tube M0. Adjust the duty cycle d of the drive signal of the switching tube M0 to increase the output voltage to: V mn = H · V in Among them, V in is the input DC voltage of the BVS; S3. Adopt the SVPWM modulation method to output V cm0 as a four-level stepped wave: Set the switching frequency and modulation ratio through the upper computer, and control the switching timing of M1 - M6. S4. Impedance-match the output of the inverter through the BVHM circuit module to obtain the simulator output voltage V b_o With respect to V cm0 Transfer function of to achieve voltage conversion: where S5. Control the output voltage in real time according to formula (8): According to formula (8), when V in and the simulator BVHM circuit parameters are determined, the magnitude of V b_o is only related to the duty cycle d. The host computer software flexibly adjusts the output V o magnitude by adjusting the coefficient K b_o .

9. A storage medium, on which a computer program is stored, characterized in that, When the computer program is executed by the processor, it realizes the operation method of the bearing voltage simulator for electric corrosion test of motor bearings according to claim 8.

10. A computer device, characterized in that, It includes: a memory, a processor, and a computer program stored on the memory and operable on the processor. The processor executes the program to realize the operation method of the bearing voltage simulator for electric corrosion test of motor bearings according to claim 8.

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