Electric drive assembly shaft electric test method and system and electronic equipment

Abstract

The invention provides an electric drive assembly shaft electricity test method and system and electronic equipment, and relates to the technical field of electric drive assembly shaft electricity detection. According to the method, on one hand, different driving working conditions are simulated based on simulation parameters set by a user, and power parameters of an electric drive assembly under the different driving working conditions are determined; and the electric drive assembly is controlled to operate according to the power parameters under the different driving working conditions, and shaft voltage data in the operation process of the electric drive assembly are collected through a shaft electric sensor. Therefore, different working condition tests can be carried out by simulating the whole vehicle, and the shaft voltage of the electric drive assembly under different working conditions can be accurately measured in real time, so that the electric corrosion risk of the bearing of the electric drive assembly can be evaluated. And on the other hand, the mounting hole is formed in the bearing end cover of the motor of the electric drive assembly, so that the shaft electric sensor can extend into the mounting hole to be connected with the motor shaft, the shaft voltage of the electric drive assembly under different working conditions can be measured, the overall structure of the electric drive assembly is slightly changed, and the test clutter is small.

Description

Technical Field

[0001] The present application relates to the technical field of shaft electrical detection of electric drive assemblies, and particularly to a shaft electrical test method, system and electronic device for electric drive assemblies. Background Art

[0002] Compared with traditional fuel vehicles, electric vehicles and hybrid vehicles are prone to form excessive shaft voltages on the inner and outer rings of the motor bearings in the electric drive assembly due to their unique high-frequency electromagnetic conversion, thus breaking down the lubricating oil film to generate shaft current, and further causing shaft electrical corrosion resulting in problems such as bearing ablation and noise. Moreover, under the trend of high frequency, high voltage, high speed and high power of electric drive assemblies, the risk of bearing electrical corrosion in vehicle electric drive assemblies is becoming increasingly serious and has attracted extensive attention from major manufacturers.

[0003] In related technologies, the shaft electrical test of the electric drive assembly is mainly carried out in the early stage of the design and development of the electric drive assembly to evaluate the risk of bearing electrical corrosion of the electric drive assembly for relevant optimization. However, most of them have the following problems: 1. The structure of the electric drive assembly is changed too much, which is likely to affect the original lubrication boundary of the bearing, and further affect the test effect; 2. Detection is not carried out in combination with specific working conditions, and the detection results are not comprehensive enough. Summary of the Invention

[0004] The present application provides a shaft electrical test method, system and electronic device for electric drive assemblies, which can simulate different working condition tests with a whole vehicle mounted during the shaft electrical test of the electric drive assembly, and have less modification to the structure of the electric drive assembly, and can simply and accurately measure the shaft voltage of the electric drive assembly under different working conditions.

[0005] In the first aspect of the embodiments of the present application, a shaft electrical test method for an electric drive assembly is provided. The electric drive assembly includes a motor, and mounting holes are provided on both sides of the bearing end cover of the motor. The motor shaft of the motor is connected to a shaft electrical sensor through the mounting holes; The method includes: Simulating different driving conditions based on the simulation parameters set by the user, and determining the power parameters of the electric drive assembly under different driving conditions; Controlling the electric drive assembly to operate according to the power parameters under different driving conditions, and collecting shaft voltage data during the operation of the electric drive assembly through the shaft electrical sensor.

[0006] Optionally, the method further includes: Performing shaft electrical test access verification based on the installation parameters of the electric drive assembly, and performing condition simulation based on the simulation parameters set by the user when the verification is passed.

[0007] Optionally, the installation parameters include the operating state of the electric drive assembly, the contact states of all contact points between the electric drive assembly and the vehicle bench, and the installation state of the shaft voltage sensor; The method further includes: When the operating state of the electric drive assembly is normal, the contact states of all contact points are in an insulated state, and the installation state of the shaft voltage sensor is in a correct state, it is determined that the verification is passed.

[0008] Optionally, the method further includes: Obtain the theoretical resistance value and the measured resistance value of the motor; When the theoretical resistance value is greater than or equal to the measured resistance value, it is determined that the installation state of the shaft voltage sensor is in a correct state; when the theoretical resistance value is less than the measured resistance value, it is determined that the installation state of the shaft voltage sensor is in an incorrect state.

[0009] Optionally, different driving conditions are simulated based on the simulation parameters set by the user, and the dynamic parameters of the electric drive assembly under different driving conditions are determined, including: Based on the simulation parameters set by the user, determine the battery voltage and driving resistance value of the vehicle simulation; Perform driving condition simulation based on the battery voltage and driving resistance value, and determine the dynamic parameters of the electric drive assembly under the driving condition, where the dynamic parameters include the driving torque or braking torque of the electric drive assembly.

[0010] Optionally, the method further includes: Analyze the shaft voltage data to obtain the bearing electrical corrosion risk assessment result of the electric drive assembly.

[0011] Based on the same inventive concept, a second aspect of the embodiments of the present application provides a shaft voltage test device for an electric drive assembly. The electric drive assembly includes a motor, and mounting holes are provided on both sides of the bearing end cover of the motor. The motor shaft of the motor is connected to a shaft voltage sensor through the mounting holes; The above device includes: A driving condition simulation module, configured to simulate different driving conditions based on the simulation parameters set by the user, and determine the dynamic parameters of the electric drive assembly under different driving conditions; A shaft voltage acquisition module, configured to control the electric drive assembly to operate according to the dynamic parameters under different driving conditions, and collect shaft voltage data during the operation of the electric drive assembly through the shaft voltage sensor.

[0012] Based on the same inventive concept, in the third aspect of the embodiments of the present application, an electric drive assembly shaft electricity test system is provided. The system includes: a vehicle test bench, an electric drive assembly to be detected, and a shaft electricity sensor. The electric drive assembly to be detected is installed on the vehicle test bench. The electric drive assembly to be detected includes a motor. Installation holes are provided on both sides of the bearing end cover of the motor. The shaft electricity sensor is connected to the motor shaft of the motor through the installation holes. Among them, The vehicle test bench is configured to simulate different driving conditions based on simulation parameters set by a user, determine the power parameters of the electric drive assembly under different driving conditions, and control the electric drive assembly to operate according to the power parameters; The shaft electricity sensor is configured to collect shaft voltage data during the operation of the electric drive assembly.

[0013] Optionally, one end of the shaft electricity sensor extending into the hole and connected to the motor shaft is made of conductive carbon fiber. The housing of the shaft electricity sensor is insulated and sealed. The internal shaft electricity wire of the shaft electricity sensor is a self-shielded wire.

[0014] Optionally, the vehicle test bench includes a battery module, a vehicle resistance module, a power control module, a first load motor, a second load motor, and a battery simulator; Among them, the battery module is connected to the electric drive assembly through the battery simulator. The vehicle resistance module is respectively connected to two output ends of the electric drive assembly through the first load motor and the second load motor. The power control module is connected to the motor controller of the electric drive assembly; The battery module is configured to determine the battery voltage simulated by the vehicle based on the simulation parameters set by the user, and send the battery voltage to the battery simulator, so that the battery simulator simulates the battery conditions based on the battery voltage; The vehicle resistance module is configured to determine the driving resistance value simulated by the vehicle based on the simulation parameters set by the user, and send the driving resistance value to the first load motor and the second load motor, so that the first load motor and the second load motor simulate the load conditions based on the driving resistance value; The power control module is configured to determine the power parameters of the electric drive assembly under the battery conditions and the load conditions, and send the power parameters to the motor controller of the electric drive assembly, so that the motor controller controls the electric drive assembly to operate according to the power parameters.

[0015] Based on the same inventive concept, in the fourth aspect of the embodiments of the present application, an electronic device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes, it implements the electric drive assembly shaft electricity test method proposed in the first aspect of the present application.

[0016] Compared with the prior art, the present application has the following advantages: The embodiment of the present application provides an electric drive assembly shaft electricity test method. First, different driving conditions are simulated based on the simulation parameters set by the user, and the power parameters of the electric drive assembly under different driving conditions are determined; then, the electric drive assembly is controlled to operate according to the power parameters under different driving conditions, and the shaft voltage data during the operation of the electric drive assembly is collected by a shaft electricity sensor. Thus, it is possible to simulate different condition tests with a vehicle mounted, measure the shaft voltage of the electric drive assembly in real time and accurately under different conditions, so as to evaluate the risk of bearing electrical corrosion of the electric drive assembly, which is convenient for subsequent related optimizations. At the same time, the electric drive assembly includes a motor, and mounting holes are provided on both sides of the bearing end cover of the motor, and the motor shaft of the motor is connected to the shaft electricity sensor through the mounting holes. Thus, by machining mounting holes on the bearing end cover of the motor of the electric drive assembly, the shaft electricity sensor can be used to extend into the mounting holes and connect with the motor shaft, and then the shaft voltage of the electric drive assembly under different conditions can be measured simply and accurately. The overall structure of the electric drive assembly has few changes, the test clutter is small, and it does not affect the original bearing lubrication, which can well meet the relevant test requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0018] Figure 1 is a flowchart of an electric drive assembly shaft electricity test method in an embodiment of the present application; Figure 2 is a schematic structural diagram of an electric drive assembly shaft electricity test system in an embodiment of the present application; Figure 3 is a flowchart of an electric drive assembly shaft electricity test method in another embodiment of the present application; Figure 4 is a schematic diagram of the functional modules of an electric drive assembly shaft electricity test device in an embodiment of the present application; Figure 5 is a schematic structural diagram of an electronic device in an embodiment of the present application.

[0019] Reference numerals: 1, electric drive assembly; 101, motor shaft; 102, motor housing; 103, bearing end cover; 2, first shaft electricity sensor; 3, second shaft electricity sensor; 4, first load motor; 5, second load motor; 6, vehicle resistance module; 7, bench control system; 8, battery module; 9, power control module; 10, shaft electricity data acquisition; 11, battery simulator. Detailed implementation mode

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0021] The motor shaft voltage of the automotive electric drive assembly refers to the voltage across the bearings at both ends of the motor during motor operation. Under normal circumstances, when the shaft voltage is low, the lubricating oil film existing between the motor shaft and the bearing can play a good insulating role. However, if for some reason the shaft voltage rises to a certain value, the oil film will be broken down and discharge, forming a loop for the generation of shaft current. The shaft current will not only destroy the stability of the oil film, gradually deteriorate the lubricating and cooling oil quality, but also, since the shaft current passes through the metal contact points between the bearing and the shaft, the metal contact points are very small and the current density is very large, high temperature will be generated instantaneously, causing local melting of the bearing and leading to bearing electro-corrosion. The melted bearing alloy splashes under the action of the rolling pressure, burning small pits on the inner surface of the bearing, and the bearing will be damaged due to accelerated mechanical wear. This will seriously affect the operating performance and safety performance of the motor, posing a safety hazard to vehicle driving.

[0022] In related technologies, to reduce the risk of bearing electro-corrosion, mainly through conducting shaft voltage tests on the electric drive assembly in the early stage of the design and development of the electric drive assembly to evaluate the risk of bearing electro-corrosion of the electric drive assembly, so as to carry out relevant optimizations. However, most of them have the following problems: 1. The structure of the electric drive assembly is changed too much, which is likely to affect the original lubrication boundary of the bearing, and thus affect the test results; 2. Detection is not carried out in combination with specific working conditions, and the detection results are not comprehensive enough.

[0023] In view of this, the present application proposes a shaft voltage test method for an electric drive assembly. The electric drive assembly includes a motor, and mounting holes are provided on both sides of the bearing end cover of the motor. The motor shaft of the motor is connected to a shaft voltage sensor through the mounting holes. Thus, by machining mounting holes on the bearing end cover of the motor of the electric drive assembly, the shaft voltage sensor can be inserted into the mounting holes to be connected to the motor shaft, and then the shaft voltage of the electric drive assembly under different working conditions can be measured simply and accurately. The overall structure of the electric drive assembly has few modifications, the test clutter is small, and the original bearing lubrication is not affected, which can well meet the relevant test requirements. On this basis, different driving conditions are simulated based on the simulation parameters set by the user, and the dynamic parameters of the electric drive assembly under different driving conditions are determined; then, the electric drive assembly is controlled to operate according to the dynamic parameters under different driving conditions, and the shaft voltage data during the operation of the electric drive assembly is collected through the shaft voltage sensor. Thus, it is possible to simulate different working condition tests with a vehicle mounted, and measure the shaft voltage of the electric drive assembly under different working conditions in real time and accurately, so as to evaluate the risk of bearing electro-corrosion of the electric drive assembly, which is convenient for subsequent related optimizations.

[0024] First, it should be noted that in the present application, the electric drive assembly 1 includes a motor, and mounting holes are provided on both sides of the bearing end cover 103 of the motor. The motor shaft of the motor is connected to a shaft voltage sensor through the mounting holes.

[0025] The electric drive assembly 1 is usually an integrated electric drive system composed of a motor, a motor controller, and a reducer. Among them, the motor is coupled to the reducer and is used to drive the wheels to run; the motor controller is connected to the motor and is used to control the operation of the motor according to the corresponding driving or braking requirements.

[0026] Specifically, as Figure 2 shown, the motor includes a stator, a rotor, a motor shaft 101, a motor housing 102, a bearing end cover 103, and other accessories, such as an encoder (position sensor), a temperature sensor, etc. Among them, the stator is the stationary part, which includes a stator core (stacked by silicon steel sheets) and a stator winding (wound by copper wires), and is used to generate a rotating magnetic field (for an AC motor) or a stationary magnetic field (for a DC motor) after being energized. The rotor is the rotating part, which may include permanent magnets (permanent magnet motor) or bars (induction motor), and is used to generate torque under the action of the magnetic field. The motor shaft 101 is used to support the rotor to ensure its smooth rotation and reduce friction, and usually uses rolling bearings (such as deep groove ball bearings) or sliding bearings. The motor housing 102 is used to enclose the stator and rotor, providing mechanical protection and heat dissipation. The bearing end cover 103 is fixed at both ends of the motor housing 102 and is used to support the bearing and protect the internal structure, and is usually made of metal (such as aluminum alloy) or high-strength plastic.

[0027] In this embodiment, by providing mounting holes on both sides of the bearing end cover 103 of the motor, the first shaft electrical sensor 2 and the second shaft electrical sensor 3 can extend through these mounting holes to the motor shaft 101 near the inner ring of the motor bearing at both ends of the electric drive assembly 1 for measurement, so as to measure the shaft voltage of the electric drive assembly 1 in real time and accurately under different working conditions. It should be noted that the motor shaft 101 is in contact with the inner ring of the motor bearing. Therefore, it can be considered that the two are at the same electric potential, that is, the voltage of the inner ring of the motor bearing is equal to the voltage at the motor shaft 101. At the same time, the outer ring of the motor bearing is in contact with the motor housing 102, and the motor housing 102 is grounded with a voltage of 0. Therefore, the voltage of the outer ring of the motor bearing is 0. Thus, the shaft voltage of the motor bearing to be detected is numerically equal to the voltage of the inner ring of the motor bearing. Therefore, the voltage at the motor shaft 101 can be tested by the shaft electrical sensor, that is, the shaft voltage of the motor bearing can be obtained.

[0028] Among them, the mounting hole can be a threaded hole. The first shaft electrical sensor 2 and the second shaft electrical sensor 3 refer to sensors for testing the voltage of the motor bearing. The extending parts of the first shaft electrical sensor 2 and the second shaft electrical sensor 3 are made of conductive carbon fiber and can always be in contact with the end of the motor shaft to indirectly detect the voltage of the inner ring of the motor bearing. The housings of the first shaft electrical sensor 2 and the second shaft electrical sensor 3 are made of insulating materials and can be self-sealed, and the internal shaft electrical wires are self-shielded wires. Thus, by making minor modifications to the overall structure of the electric drive assembly 1, the detection of the motor shaft voltage can be achieved, with small test clutter and no impact on the original bearing lubrication, and it can well meet the relevant test requirements.

[0029] On this basis, please refer to Figure 1 , Figure 1 which is a flowchart of a shaft electrical test method for an electric drive assembly proposed in an embodiment of the present application. This method can be applied to a bench control system to achieve the detection of the shaft voltage of the electric drive assembly. Specifically, as shown in Figure 1 , this method includes the following steps: S101: Simulate different driving conditions based on the simulation parameters set by the user, and determine the dynamic parameters of the electric drive assembly under different driving conditions.

[0030] In this embodiment, the simulation parameters include vehicle model parameters, vehicle control logic parameters, design parameters of the electric drive assembly, etc. Through the combined action of these parameters, the simulation of driving conditions is realized. At the same time, based on these simulation parameters, the dynamic parameters required by the electric drive assembly can be calculated, including driving torque or braking torque, etc., to test the shaft voltage performance of the electric drive assembly under simulated conditions.

[0031] On this basis, users can adjust these simulation parameters to simulate different driving conditions, so as to detect the shaft voltage performance of the electric drive assembly under different driving conditions and achieve verification coverage for various different vehicles, such as the performance coverage and efficiency analysis of the electric drive assembly, etc.

[0032] Specifically, the condition simulation mainly includes extreme condition simulation and common condition simulation to detect the reliability, safety margin and fault protection ability of the electric drive assembly under extreme conditions, as well as to verify the efficiency, smoothness and durability of the electric drive assembly in real driving scenarios.

[0033] Among them, the extreme condition simulation is mainly based on the vehicle model parameters and the design parameters of the electric drive assembly to understand the torque and speed range of the motor in the electric drive assembly. Then, by simulating extreme conditions such as the highest voltage or the rated voltage, the dynamic parameters of the electric drive assembly under such extreme conditions are determined, including the maximum design torque and speed (which can be adjusted according to specific test conditions), so as to detect the shaft voltage performance of the electric drive assembly under extreme conditions. For example, when simulating the rated voltage condition, continuously apply the motor peak torque (such as for 30 seconds) or peak power (such as for 60 seconds) to the drive assembly, and monitor the shaft voltage of the motor during this process to determine whether the electric drive assembly triggers overcurrent protection. Or, simulate high-temperature environment conditions or low-temperature environment conditions to detect the output ability of the electric drive assembly under extreme temperature environments and determine whether the electric drive assembly triggers overtemperature protection.

[0034] In addition, it is also possible to determine the specific torque of the electric drive assembly at a specific vehicle speed by simulating other specific vehicle speed conditions, so as to detect the shaft voltage performance of the electric drive assembly under some special conditions. For example, simulate rapid acceleration and rapid deceleration conditions to determine the high-frequency switching torque of the electric drive assembly under such extreme change conditions, such as the motor torque changing from 0 to 100% and then from 100% to 0 within 2 seconds. Then, by monitoring the shaft voltage of the motor during this process, analyze the response performance of the electric drive assembly and judge whether the response of the electric drive assembly is fast enough.

[0035] The common condition simulation is mainly based on the vehicle model parameters and vehicle control logic to simulate some common conditions, including but not limited to the 100-kilometer acceleration and deceleration conditions with SOC (State of Charge, used to reflect the remaining battery power) at 100%, the WLTC condition (Worldwide Harmonized Light Vehicles Test Cycle), or the CLTC condition (China Light-duty Vehicle Test Cycle), etc. And by determining the dynamic parameters such as driving torque and braking torque of the electric drive assembly under such common scenario conditions, detect the shaft voltage performance of the electric drive assembly under common conditions.

[0036] For example, run standard vehicle speed curves such as WLTC and CLTC, simulate vehicle inertia and road load through a test bench, and determine dynamic parameters such as driving torque and braking torque of the electric drive assembly under such load conditions. Taking the CLTC condition as an example, the CLTC standard vehicle speed curve consists of three speed intervals, with a total duration of 1800 seconds (30 minutes) and a driving distance of approximately 14.48 km: the low-speed section (0 - 60 km / h) simulates urban congestion with frequent acceleration and deceleration (such as starting and stopping at traffic lights); the medium-speed section (40 - 80 km / h) simulates driving on urban main roads with a slightly increased proportion of constant speed; the high-speed section (80 - 114 km / h) simulates ring roads or short-distance highways, but with a shorter duration.

[0037] S102: Control the electric drive assembly to operate according to the dynamic parameters under different driving conditions, and collect the shaft voltage data during the operation of the electric drive assembly through a shaft voltage sensor.

[0038] In this embodiment, during a shaft voltage test, after determining the dynamic parameters required by the electric drive assembly under the driving conditions through driving condition simulation, the dynamic parameters are sent to the motor controller of the electric drive assembly to control the motor to operate according to the dynamic parameters under this driving condition. Then, the shaft voltage data during the operation of the electric drive assembly is collected through a shaft voltage sensor, and can be further stored and displayed through a shaft voltage data acquisition device for analyzing the performance of the electric drive assembly under this condition.

[0039] Specifically, the above method further includes: analyzing the shaft voltage data to obtain an evaluation result of the bearing electrical corrosion risk of the electric drive assembly.

[0040] In this embodiment, the bearing electrical corrosion risk of the electric drive assembly can be evaluated by combining the bearing electrical corrosion risk threshold, and the risk level can be divided accordingly to obtain the bearing electrical corrosion risk evaluation result. Among them, the bearing electrical corrosion risk threshold is usually 0.5 - 2V (depending on the insulating performance of the grease).

[0041] When specifically implemented, if the peak value of the shaft voltage < 0.5V, it is determined that the bearing electrical corrosion risk evaluation result is low risk, and at this time, it is considered that the probability of causing bearing electrical corrosion of the electric drive assembly under the current condition is small; if 0.5V < the peak value of the shaft voltage < 2V, it is determined that the bearing electrical corrosion risk evaluation result is medium risk, and at this time, it is considered that the probability of causing bearing electrical corrosion of the electric drive assembly under the current condition is large; if the peak value of the shaft voltage > 2V, it is determined that the bearing electrical corrosion risk evaluation result is high risk, and at this time, it is considered that the probability of causing bearing electrical corrosion of the electric drive assembly under the current condition is close to 100%, and corresponding suppression measures need to be taken immediately.

[0042] In addition, when evaluating the risk of bearing electro-corrosion, parameters such as voltage frequency, bearing current density, and grease resistivity can also be combined for comprehensive judgment to obtain a more accurate assessment result of the bearing electro-corrosion risk.

[0043] Optionally, in the above step S101, different driving conditions are simulated based on the simulation parameters set by the user, and the dynamic parameters of the electric drive assembly under different driving conditions are determined, including: S101-1: Based on the simulation parameters set by the user, determine the battery voltage and driving resistance value for vehicle simulation.

[0044] In this embodiment, the simulation parameters include vehicle model parameters, vehicle control logic parameters, design parameters of the electric drive assembly, etc.

[0045] Among them, the vehicle model parameters include vehicle mass, battery design parameters, wheel rolling radius, tire dynamic characteristics (such as rolling resistance coefficient, slip ratio, etc.), wind resistance coefficient, inertia equivalent parameters, axle load distribution, etc., which can be used to calculate vehicle driving resistance (such as rolling resistance, wind resistance, ramp resistance) and the required torque or power of the electric drive assembly.

[0046] The vehicle control logic parameters define the control strategies of the vehicle control unit (VCU) or the motor control unit (MCU), including driving mode logic, torque demand logic, fault protection logic, etc., which directly affect the response characteristics of the electric drive system and can be used to simulate the input of the driver and the real-time control behavior of the VCU or MCU in a real vehicle.

[0047] The design parameters of the electric drive assembly include motor parameters (such as rated speed, maximum speed), motor controller parameters (such as DC bus voltage, maximum output current), and reducer parameters (such as reduction ratio, transmission efficiency), which can be used to simulate the actual output capacity, efficiency boundary, and dynamic response of the electric drive assembly.

[0048] Exemplarily, during the simulation test of common working conditions, by simulating the vehicle driving in scenarios such as WLTC and CLTC, the current battery voltage is simulated and calculated in real time according to the battery parameters, the relationship between the current SOC and the measured current, and the driving resistance value currently received by the vehicle can be simulated and calculated in real time according to the vehicle model parameters.

[0049] S101-2: Conduct driving condition simulation based on the battery voltage and driving resistance value, and determine the dynamic parameters of the electric drive assembly under the driving condition. The dynamic parameters include the driving torque or braking torque of the electric drive assembly.

[0050] In this embodiment, after determining the current battery voltage and driving resistance value of the vehicle, the battery simulator can simulate the battery working conditions based on the battery voltage, and the load motor can simulate the load working conditions based on the driving resistance value, so as to continuously simulate the voltage conditions and load conditions faced by the electric drive assembly during the vehicle operation. Meanwhile, based on the vehicle type parameters and vehicle control logic parameters, the driving torque or braking torque and other power parameters required for vehicle driving can be simulated and calculated, and the motor controller can control the motor operation based on the power parameters, so as to detect the shaft voltage performance of the electric drive assembly under such battery working conditions and load working conditions.

[0051] In addition, by adjusting the vehicle speed, battery SOC, etc., the shaft voltage performance of the electric drive assembly under different driving conditions can be detected. Also, by adjusting the vehicle type parameters, vehicle control logic parameters, etc., the verification coverage of various different vehicles can be achieved.

[0052] Optionally, the above method further includes: Conducting shaft voltage test access verification based on the installation parameters of the electric drive assembly, and performing working condition simulation based on the simulation parameters set by the user when the verification is passed.

[0053] In this embodiment, after setting up the test environment, it is necessary to conduct access inspections on the electric drive assembly and its installation status according to the access requirements of the electric drive assembly shaft voltage test, including but not limited to the operating status inspection of the electric drive assembly, the insulation inspection of all contact points between the electric drive assembly and the vehicle bench, and the installation status inspection of the shaft voltage sensor, so as to ensure the accuracy of subsequent tests.

[0054] Specifically, the installation parameters obtained by detection can be compared with the shaft voltage test access requirement parameters of the industry standard to determine whether the installation situation of this test meets the shaft voltage test access requirements, and perform working condition simulation based on the simulation parameters set by the user when the verification is passed.

[0055] Furthermore, the installation parameters include the operating status of the electric drive assembly, the contact status of all contact points between the electric drive assembly and the vehicle bench, and the installation status of the shaft voltage sensor. When the operating status of the electric drive assembly is normal, the contact status of all contact points is insulated, and the installation status of the shaft voltage sensor is correct, it is determined that the verification is passed.

[0056] In this embodiment, first, if there are potential faults in the electric drive assembly (such as bearing wear, local short - circuit of the winding), it may introduce additional shaft voltage noise, resulting in distorted test results. For example, bearing wear will cause increased mechanical vibration, which may generate frictional static electricity, interfering with the true PWM (Pulse Width Modulation) harmonic shaft voltage signal. Therefore, only when the electric drive assembly itself has normal performance and can operate healthily, can different working conditions tests be carried out on the electric drive assembly to accurately reflect its true shaft voltage characteristics under working conditions such as WLTC or CLTC.

[0057] Specifically, during implementation, the operating state of the electric drive assembly can be comprehensively judged by detecting information such as the insulation resistance of the motor (such as the resistance between motor phases, the DC resistance of the winding), the vibration speed of the motor during no - load operation, the no - load current of the motor at rated speed, the working efficiency, over - current, and over - temperature alarm conditions of the motor under a certain load.

[0058] Secondly, if the housing of the electric drive assembly is in metal contact with the test bench, a grounding loop will be formed, causing the shaft voltage of the electric drive assembly to be shunted, and then resulting in the measured value of the shaft voltage being lower than the true value. At the same time, the metal contact between the housing of the electric drive assembly and the test bench will also introduce power - frequency interference (such as 50Hz noise), masking the high - frequency PWM harmonic signal, and thus affecting the detection accuracy of the shaft voltage of the electric drive assembly. Therefore, it is necessary to ensure that the contact state of all contact points between the electric drive assembly and the vehicle test bench is in an insulated state to avoid affecting the electric drive assembly.

[0059] Specifically, during implementation, an insulating gasket can be installed between the motor mounting flange and the vehicle test bench, and then the resistance on both sides of the gasket is measured. If the resistance > 100MΩ, it can be considered that the electric drive assembly and the vehicle test bench are completely insulated.

[0060] In addition, if the shaft voltage sensor is wrongly wired, for example, the ground wire of the shaft voltage sensor is wrongly connected to the vehicle test bench, it will introduce common - mode noise, affecting the detection accuracy of the shaft voltage of the electric drive assembly. Therefore, it is necessary to ensure that the installation state of the shaft voltage sensor is in the correct state to collect the correct shaft voltage of the electric drive assembly.

[0061] Specifically, during implementation, the theoretical resistance value and the measured resistance value of the motor can be obtained and compared to judge whether the installation state of the shaft voltage sensor is correct. For example, the theoretical resistance value of the motor can be calculated by the following formula :

[0062] where, is the theoretical resistance value of the motor, Z is a constant, and any constant value between 1.5 and 2 can be taken. is the resistivity of the motor bearing, and L is the length of the motor bearing. is the cross-sectional area of the motor bearing. is the resistance of the shaft voltage sensor.

[0063] Then, directly measure the resistance value of the lead wire of the shaft voltage sensor at both ends of the motor with a multimeter to obtain the measured resistance value of the motor.

[0064] After that, compare the theoretical resistance value with the measured resistance value: when the theoretical resistance value is greater than or equal to the measured resistance value, determine that the installation state of the shaft voltage sensor is the correct state; when the theoretical resistance value is less than the measured resistance value, determine that the installation state of the shaft voltage sensor is the wrong state.

[0065] Among them, if the measured resistance value of the motor is significantly higher than the theoretical resistance value, it indicates that there are the following problems in the installation of the shaft voltage sensor: poor contact between the carbon brush and the bearing (oxidation, insufficient pressure), loose or corroded cable connection points, and too large reference ground connection impedance (such as poor grounding of the motor housing). Therefore, only when the theoretical resistance value of the motor is greater than or equal to the measured resistance value, the shaft voltage sensor is considered to be correctly installed.

[0066] Please refer to Figure 2 , based on the same inventive concept, the second aspect of the embodiment of the present application provides an electric drive assembly shaft voltage test system, which includes: a vehicle test bench (i.e., Figure 2 the test bench control system 7 in ), the electric drive assembly 1 to be detected, and a shaft voltage sensor. The electric drive assembly 1 to be detected is installed on the vehicle test bench. The electric drive assembly 1 to be detected includes a motor. Installation holes are provided on both sides of the bearing end cover 103 of the motor. The shaft voltage sensor is connected to the motor shaft through the installation holes; among them, the vehicle test bench is used to simulate different driving conditions based on the simulation parameters set by the user, determine the power parameters of the electric drive assembly 1 under different driving conditions, and control the electric drive assembly 1 to operate according to the power parameters;

[0067] Optionally, one end of the shaft voltage sensor extending into the hole and connected to the motor shaft is made of conductive carbon fiber. The housing of the shaft voltage sensor is insulated and sealed, and the internal shaft voltage wire of the shaft voltage sensor is a self-shielded wire.

[0068] Optionally, the vehicle test bench includes a battery module 8, a vehicle resistance module 6, a power control module 9, a first load motor 4, a second load motor 5, and a battery simulator 11; Among them, the battery module 8 is connected to the electric drive assembly 1 through the battery simulator 11. The vehicle resistance module 6 is respectively connected to the two output ends of the electric drive assembly 1 through the first load motor 4 and the second load motor 5. The power control module 9 is connected to the motor controller of the electric drive assembly 1; The battery module 8 is used to determine the battery voltage for vehicle simulation based on the simulation parameters set by the user, and send the battery voltage to the battery simulator 11, so that the battery simulator 11 simulates the battery working conditions based on the battery voltage; The vehicle resistance module 6 is used to determine the driving resistance value for vehicle simulation based on the simulation parameters set by the user, and send the driving resistance value to the first load motor 4 and the second load motor 5, so that the first load motor 4 and the second load motor 5 simulate the load working conditions based on the driving resistance value; The power control module 9 is used to determine the power parameters of the electric drive assembly 1 under the battery working conditions and the load working conditions, and send the power parameters to the motor controller of the electric drive assembly 1, so that the motor controller controls the electric drive assembly 1 to operate according to the power parameters.

[0069] On this basis, the actual operation process of the shaft electricity test in another embodiment of this application is as Figure 3 shown: S201: Prepare the test samples and build the vehicle test bench.

[0070] As Figure 2 shown, first, determine the test samples required for this time, that is, the electric drive assembly 1 to be detected. Then, install the electric drive assembly 1 on the vehicle test bench according to the vehicle state. The output ends of the electric drive assembly 1 are respectively connected to the first load motor 4 and the second load motor 5. The first load motor 4 and the second load motor 5 are connected to the vehicle resistance module 6 in the test bench control system 7. One end of the first shaft electricity sensor 2 and the second shaft electricity sensor 3 is inserted into the electric drive assembly 1 through the mounting hole on the bearing end cover 101 of the motor and connected to the motor shaft 101, and the other end is connected to the shaft electricity data acquisition 10. And both the first shaft electricity sensor 2 and the second shaft electricity sensor 3 are grounded with the motor housing 102 of the electric drive assembly 1. Connect the battery simulator 11 to the electric drive assembly 1 (using high-voltage wire harnesses) and the battery module 8 in the test bench control system 7 respectively. Connect the motor controller in the electric drive assembly 1 to the power control module 9 in the test bench control system 7. Finally, perform insulation treatment on all contact points between the electric drive assembly 1 and the vehicle test bench.

[0071] S202: Judge whether the test access inspection is qualified.

[0072] Perform an access check on the electric drive assembly 1 and its installation status in accordance with the access requirements for the shaft electric test of the electric drive assembly. If the access check is qualified, execute step S203 or S204. If the access check is unqualified, return to step S201 to readjust the states of the electric drive assembly 1, the shaft electric sensor 2, the shaft electric data acquisition device 10, and the bench control system 7 and their connections to each other, and perform the test access check again.

[0073] Among them, for the specific process of the test access check, please refer to the foregoing embodiments and will not be elaborated here.

[0074] S203: Set and run under extreme conditions.

[0075] First, according to the design of the electric drive assembly 1 and the parameters of the vehicle it is installed on, understand the motor torque and speed range of the electric drive assembly 1, and then set extreme conditions. The entire condition includes but is not limited to the maximum design torque and speed of the electric drive assembly 1 under the highest voltage or rated voltage (which can be adjusted according to the specific test situation) and specific torques at other specific vehicle speeds for extreme condition verification.

[0076] S204: Set and run under common conditions.

[0077] Common conditions include but are not limited to the acceleration and deceleration per 100 kilometers and the WLTC condition or the CLTC condition with the SOC at 100% (which can be adjusted according to the specific test situation), and other common conditions used by users can also be set.

[0078] In the specific implementation process, according to the design parameters of the electric drive assembly 1, the parameters of the vehicle it is installed on, and the vehicle control logic, determine the battery voltage simulated by the whole vehicle through the battery module 8, and send the battery voltage to the battery simulator 11 to enable the battery simulator 11 to simulate the battery condition based on the battery voltage. At the same time, determine the driving resistance value simulated by the whole vehicle through the vehicle resistance module 6, and send the driving resistance value to the first load motor 4 and the second load motor 5 to enable the first load motor 4 and the second load motor 5 to simulate the load condition based on the driving resistance value. Determine the power parameters of the electric drive assembly 1 under the battery condition and the load condition through the power control module 9, and send the power parameters to the motor controller of the electric drive assembly 1 to enable the motor controller to control the electric drive assembly 1 to operate according to the power parameters.

[0079] S205: Collect and analyze shaft voltage data.

[0080] The shaft voltage data of the electric drive assembly 1 during operation under different working conditions is collected by the first-axis electric sensor 2 and the second-axis electric sensor 3, and sent to the shaft electric data acquisition unit 10 (the number of acquisition channels ≥ 2). The shaft electric data acquisition unit 10 records and displays the shaft voltage waveform data under each working condition, realizing the data analysis and recording of each working condition of the shaft electric test of the electric drive assembly. For example, based on the shaft voltage waveform and the shaft voltage peak value under each working condition, the bearing electric corrosion risk of the electric drive assembly 1 can be evaluated.

[0081] Among them, the shaft electric data acquisition unit 10 can be one or more of a high-speed data acquisition module, an oscilloscope, a spectrum analyzer, or other data acquisition and analysis modules.

[0082] On the one hand, in this embodiment, by machining and installing holes on the bearing end cover of the electric drive assembly motor, the shaft electric sensor can be used to extend into the installation hole and connect with the motor shaft of the motor, thereby simply and accurately measuring the shaft voltage of the electric drive assembly under different working conditions. The overall structure of the electric drive assembly has few modifications, small test clutter, and does not affect the original bearing lubrication, and can well meet the relevant test requirements. On the other hand, through the bench control system, different working condition tests are simulated by carrying a whole vehicle, and the shaft voltage of the electric drive assembly under different working conditions is measured in real time and accurately, so as to be used to evaluate the bearing electric corrosion risk of the electric drive assembly, facilitating subsequent related optimizations.

[0083] Please refer to Figure 4 , based on the same inventive concept, in the third aspect of the embodiments of the present application, an electric drive assembly shaft electric test device is provided. Among them, the electric drive assembly includes a motor, and installation holes are provided on both sides of the bearing end cover of the motor. The motor shaft of the motor is connected to the shaft electric sensor through the installation hole; The above-mentioned electric drive assembly shaft electric test device 400 includes: A working condition simulation module 401, configured to simulate different driving working conditions based on the simulation parameters set by the user, and determine the power parameters of the electric drive assembly under different driving working conditions; A shaft voltage acquisition module 402, configured to control the electric drive assembly to operate according to the power parameters under different driving working conditions, and collect the shaft voltage data of the electric drive assembly during operation through the shaft electric sensor.

[0084] For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For the related parts, refer to the partial description of the method embodiment.

[0085] In the fourth aspect, based on the same inventive concept, refer to Figure 5 , the embodiments of the present application provide an electronic device 500, including a processor 501 and a memory 502; the memory 502 stores machine-executable instructions that can be executed by the processor 501, and the processor 501 is configured to execute the machine-executable instructions to implement the electric drive assembly shaft electric test method proposed in the first aspect of the present application.

[0086] It should be noted that for the specific implementation of the electronic device 500 in the embodiments of the present application, reference may be made to the specific implementation of the shaft electrical test method for the electric drive assembly proposed in the first aspect of the embodiments of the present application, which will not be elaborated herein.

[0087] The embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference may be made to each other.

[0088] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, a device, or a computer program product. Therefore, the embodiments of the present application may take the form of an all-hardware embodiment, an all-software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0089] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0090] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, so that a series of operation steps are executed on the computer or other programmable terminal device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable terminal device provide for implementing the functions specified in Figure 1steps of one or more processes and / or blocks Figure 1 steps of functions specified in one or more blocks.

[0092] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0093] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0094] The above has introduced in detail a method, system and electronic device for shaft electrical testing of an electric drive assembly provided by the present application. Specific examples are used in this text to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for testing the shaft of an electric drive assembly, characterized in that: The electric drive assembly includes a motor, and mounting holes are provided on both sides of the bearing end cover of the motor, and the motor shaft of the motor is connected to the shaft electric sensor through the mounting holes; The method comprises: Simulating different driving conditions based on simulation parameters set by the user, and determining the power parameters of the electric drive assembly under different driving conditions; The electric drive assembly is controlled to operate according to the power parameters under different driving conditions, and the shaft voltage data of the electric drive assembly during operation is collected through the shaft electrical sensor.

2. The method according to claim 1, characterized in that The method further comprises: The shaft electrical test access verification is carried out based on the installation parameters of the electric drive assembly, and if the verification passes, the operating condition simulation is carried out based on the simulation parameters set by the user.

3. The method according to claim 2, characterized in that The installation parameters include the operating state of the electric drive assembly, the contact state of all contact points between the electric drive assembly and the vehicle test bench, and the installation state of the shaft electrical sensor; The method further comprises: When the operation state of the electric drive assembly is normal, the contact state of all the contact points is insulated, and the installation state of the shaft electrical sensor is correct, it is determined that the verification is passed.

4. The method according to claim 3, characterized in that The method further comprises: Obtaining a theoretical resistance value and a measured resistance value of the motor; When the theoretical resistance value is greater than or equal to the measured resistance value, the installation state of the shaft electric sensor is determined to be a correct state. When the theoretical resistance value is less than the measured resistance value, the installation state of the shaft electric sensor is determined to be an incorrect state.

5. The method according to claim 1, characterized in that Different driving conditions are simulated based on the simulation parameters set by the user, and the power parameters of the electric drive assembly under different driving conditions are determined, including: Determine the battery voltage and driving resistance value of the whole vehicle simulation based on the simulation parameters set by the user; A driving condition simulation is performed based on the battery voltage and the driving resistance value, and a power parameter of the electric drive assembly under the driving condition is determined, wherein the power parameter includes a driving torque or a braking torque of the electric drive assembly.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: The shaft voltage data is analyzed to obtain a bearing electrical corrosion risk assessment result of the electric drive assembly.

7. An electric drive assembly shaft electrical test system, characterized in that: The system comprises: a vehicle test bench, an electric drive assembly to be tested and an axle electric sensor, wherein the electric drive assembly to be tested is mounted on the vehicle test bench, the electric drive assembly to be tested comprises a motor, mounting holes are provided on both sides of the bearing end cover of the motor, and the axle electric sensor is connected to the motor shaft of the motor through the mounting holes; wherein, The vehicle test bench is used to simulate different driving conditions based on simulation parameters set by the user, determine the power parameters of the electric drive assembly under different driving conditions, and control the electric drive assembly to operate according to the power parameters; The shaft electrical sensor is used to collect shaft voltage data during the operation of the electric drive assembly.

8. The system according to claim 7, characterized in that One end of the shaft electric sensor extending into the hole and connected to the motor shaft is conductive carbon fiber, the housing of the shaft electric sensor is insulated and sealed, and the internal shaft electric conductor of the shaft electric sensor is a self-shielding wire.

9. The system according to claim 7, characterized in that The whole vehicle test bench includes a battery module, a whole vehicle resistance module, a power control module, a first load motor, a second load motor and a battery simulator; The battery module is connected to the electric drive assembly through the battery simulator, the vehicle resistance module is connected to two output ends of the electric drive assembly through the first load motor and the second load motor respectively, and the power control module is connected to the motor controller of the electric drive assembly; The battery module is used to determine the battery voltage of the whole vehicle simulation based on the simulation parameters set by the user, and send the battery voltage to the battery simulator, so that the battery simulator simulates the battery working condition based on the battery voltage; The vehicle resistance module is used to determine the driving resistance value of the vehicle simulation based on the simulation parameters set by the user, and send the driving resistance value to the first load motor and the second load motor, so that the first load motor and the second load motor perform load condition simulation based on the driving resistance value; The power control module is used to determine the power parameters of the electric drive assembly under the battery operating condition and the load operating condition, and send the power parameters to the motor controller of the electric drive assembly so that the motor controller controls the electric drive assembly to operate according to the power parameters.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the electric drive assembly shaft electrical testing method according to any one of claims 1 to 6 is implemented.

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