A durability test method for an electric drive assembly with direct current boost charging function

Abstract

The application relates to a kind of electric drive assembly endurance test methods with direct current boost charging function, comprising: S1, build system;S2, according to predetermined test, the system is built and is subjected to endurance test preliminary test;S3, the system is powered on at low voltage and high voltage, then control electric drive assembly is carried out direct current boost charging to simulation test bench high voltage power supply two in system, and the charging capacity is Q;S4, control electric drive assembly in system simulates actual operation condition of vehicle and records the mileage L1 of electric drive assembly total cost;Cycle S3 and S4, until the total mileage of electric drive assembly reaches preset service life mileage L, completes electric drive assembly driving and power generation condition endurance test and electric drive assembly direct current boost charging endurance test of system;S5, according to predetermined test, the system is built and is subjected to endurance test retest;S6, according to endurance test preliminary test result and retest result, whether normal after cycle S3 and S4 is verified to system;S7, the system is disassembled, and disassembly report is formed.

Description

Technical Field

[0001] This invention belongs to the field of new energy electric drive assemblies, specifically relating to a durability testing method for an electric drive assembly with DC boost charging function. Background Technology

[0002] New energy vehicles have entered a stage of rapid development. As the energy source of electric vehicles, the battery is the most crucial part of electric vehicles. Currently, battery voltage ranges vary. Due to the characteristic that the charging voltage of a battery must be greater than its own voltage, the battery cannot be charged when it encounters a charging station with a higher voltage than itself. DC boost function is one of the solutions to this problem.

[0003] Current electric vehicles all have lifespan requirements, and DC-DC boost, as a function in electric vehicles, also needs to meet these requirements. Therefore, long-term durability testing of the DC-DC boost function is necessary. The lifespan of current electric vehicles is generally over 10 years and 300,000 kilometers. Validating the DC-DC boost over this timeframe would require a significant amount of time and effort. Therefore, a system and method are needed to verify the durability of both the electric drive assembly and the DC-DC boost, allowing for simultaneous verification of both components while shortening the testing time.

[0004] The technical solution with application number CN201811574191.7 only describes the electric drive boost charging function, but does not describe its durability verification; there are no relevant documents on DC boost durability. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a durability testing method for an electric drive assembly with DC boost charging function, which can perform durability testing on the driving and power generation conditions of the electric drive assembly and perform durability verification on the DC boost function of the electric drive assembly according to the actual life requirements of electric vehicles.

[0006] The technical solution of this invention is as follows:

[0007] This invention provides a durability testing method for an electric drive assembly with DC boost charging function, comprising:

[0008] Step S1: Build an electric drive assembly durability testing system;

[0009] Step S2: Conduct a preliminary durability test on the constructed electric drive assembly durability test system according to the predetermined test procedures;

[0010] Step S3: Set the electric drive assembly durability test system to stand still for a preset time.

[0011] Step S4: After completing the initial durability test, the electric drive assembly durability test system is powered on with low voltage and high voltage. Then, the electric drive assembly is controlled to simulate the vehicle's DC boost charging strategy to perform DC boost charging on the simulated bench high voltage power supply in the electric drive assembly durability test system. The charging amount is Q.

[0012] Step S5: Control the electric drive assembly in the electric drive assembly durability test system to simulate the actual operating conditions of the whole vehicle, so as to consume the charging power Q of the simulated bench high voltage power supply in the electric drive assembly durability test system, and record the mileage L1 of the electric drive assembly for this test.

[0013] Repeat steps S4 and S5 until the total mileage of the electric drive assembly reaches the preset life mileage L, thus completing the durability test of the electric drive assembly drive and power generation conditions and the DC boost charging durability test of the electric drive assembly.

[0014] Step S6: Conduct a durability test retest on the constructed electric drive assembly durability test system according to the predetermined test procedures;

[0015] Step S7: Based on the initial durability test results and the retest results of the durability test, verify whether the electric drive assembly durability test system is normal after repeating steps S4 and S5.

[0016] Step S8: Disassemble the electric drive assembly durability testing system and generate a disassembly report.

[0017] Preferably, in step S1, the electric drive assembly durability testing system includes: a bench computer, an electric drive assembly consisting of a motor controller, a motor and a reducer, a power dynamometer as the motor load, a bench high-voltage power supply simulating a charging pile, a low-voltage power supply, a battery pack and a power analyzer.

[0018] The steps for setting up an electric drive assembly durability testing system include:

[0019] The motor controller is mounted on the charging pile terminal of the high-voltage power supply and the battery pack respectively.

[0020] Connect the low-voltage terminal of the motor controller to the low-voltage power supply;

[0021] Connect the motor's output end to the electric dynamometer via a speed reducer;

[0022] Connect the power analyzer to the motor controller. The power analyzer is used to measure the DC boost output power of the motor controller.

[0023] The host computer on the test bench is used to connect to the high-voltage power supply, battery pack, low-voltage power supply, motor controller, and power analyzer on the test bench.

[0024] Preferably, during the execution of step S4, the method further includes:

[0025] Step S9: If the DC boost output power measured by the power analyzer is not within the preset power range, the host computer on the test bench will output the result of failing the durability test of the electric drive assembly's drive and power generation conditions and the durability test of the electric drive assembly's DC boost charging.

[0026] Preferably, the contents of the initial durability test in step S2 and the retest of the durability test in step S6 both include:

[0027] Peak external characteristic test, insulation resistance test and motor back electromotive force test were performed on the electric drive assembly durability test system.

[0028] Preferably, the steps for performing peak out-of-peak characteristic tests on the electric drive assembly durability testing system include:

[0029] By controlling the minimum operating voltage, rated operating voltage, and maximum operating voltage of the two-output electric drive assembly of the high-voltage power supply on the test bench via the host computer, and measuring the peak external characteristics of the electric drive assembly using a power dynamometer, it is determined whether the peak external characteristics of the electric drive assembly meet the pre-specified peak external characteristic requirements.

[0030] Preferably, the steps for performing insulation resistance testing on the electric drive assembly durability testing system include:

[0031] Connect the four-phase wires connecting the motor controller and the motor, along with the high-voltage port, to the positive terminal of the insulation withstand voltage tester. Connect all terminals of the low-voltage port in the electric drive assembly durability test system, along with the housing, to the negative terminal of the insulation withstand voltage tester. Based on the test results of the insulation withstand voltage tester, determine whether the insulation requirements of the electric drive assembly meet the pre-specified insulation requirements.

[0032] Preferably, the steps for performing back EMF testing on the electric drive assembly durability testing system include:

[0033] Disconnect the three-phase copper busbar of the motor controller from the three-phase terminals of the motor. Connect the voltage probe of the oscilloscope to the U, V, and W phase lines of the motor respectively. Use a dynamometer to drive the motor to the rated maximum speed point at intervals of 1000 rpm. Test the back electromotive force of the motor's three phases with the oscilloscope to determine whether the back electromotive force meets the pre-specified back electromotive force requirements.

[0034] Preferably, the battery pack is a bench high-voltage power supply that simulates a vehicle battery pack or a real vehicle battery pack.

[0035] Preferably, in step S8, if the difference in peak external characteristic variation of the electric drive assembly durability test system in the initial test results and the retest results is within a preset variation range, the insulation resistance of the high-voltage end of the motor controller to the housing and the insulation resistance of the low-voltage end to the housing in the initial test results and the retest results are both within their respective preset resistance ranges, and the back electromotive force difference of the motor in the initial test results and the retest results is within a preset back electromotive force difference variation range, then it is determined that the electric drive assembly durability test system has successfully completed the predetermined number of electric drive assembly drive and power generation condition durability tests and electric drive assembly DC boost durability tests.

[0036] Preferably, the electric drive assembly is a water-cooled electric drive assembly or an oil-cooled electric drive assembly.

[0037] The beneficial effects of this invention are as follows:

[0038] Using the above testing method, it is possible to simultaneously perform DC boost charging durability testing and endurance testing of power generation and driving conditions on an electric drive assembly with DC boost charging functionality. During the DC boost charging durability test, the electric drive assembly boosts the DC power output from the high-voltage power supply on the test bench before outputting it to the battery pack, achieving DC boost charging of the battery pack. After the battery pack is charged, during the power generation and driving condition endurance tests, the motor in the electric drive assembly simulates the allowable operating conditions of a real vehicle by driving an electric dynamometer as a load to consume the charging power from the battery pack. By cyclically executing DC boost charging of the battery pack and then consuming the charging power through the electric drive assembly, the durability testing of the electric drive assembly's DC boost charging function and the endurance testing of the drive and power generation conditions simulating real vehicle operating conditions are simultaneously achieved. Compared to whole-vehicle verification, this significantly shortens the testing time, reduces testing resource investment, greatly improves efficiency, and lowers testing costs. Compared to manual operation, it can reduce personnel input and the risk of misoperation, improve the safety and operability of the test, speed up the bench test process, and reduce the test cost. Attached Figure Description

[0039] Figure 1 This is a block diagram of the electric drive assembly durability testing system in an embodiment of the present invention;

[0040] Figure 2 This is a flowchart of the testing method according to an embodiment of the present invention. Detailed Implementation

[0041] The following will illustrate embodiments of the present invention, along with the actual operation process of automatically controlling the DC boost function on and off using the test bench, in conjunction with the design diagrams. Because the core technical aspects of the present invention need to be protected, the embodiments shown are only a part of the content of the present invention, but all fall within the scope of protection of the present invention.

[0042] This invention provides a durability test method for an electric drive assembly with DC boost charging function. This method is used to verify the durability of the electric drive assembly under driving conditions, power generation conditions, and when performing DC boost charging function.

[0043] Reference Figure 2 The method in this embodiment of the invention includes:

[0044] Step S101: Set up the electric drive assembly durability test system.

[0045] In this embodiment, reference is made to Figure 1 The modules or devices involved in the system include: a host computer on the test bench, an electric drive assembly consisting of a motor controller, a motor and a reducer, a power dynamometer as the motor load, a high-voltage power supply for simulating a charging pile on the test bench, a low-voltage power supply, a battery pack and a power analyzer.

[0046] In this embodiment, the electric drive assembly is the test sample to be subjected to durability testing. The electric drive assembly can be either water-cooled or oil-cooled; the cooling method of the electric drive assembly does not affect the durability test results. The connection relationship between the internal motor controller, motor, and reducer of the electric drive assembly is existing technology. The bench high-voltage power supply one is used to output DC voltage for the charging pile, and the battery pack is either a bench high-voltage power supply two simulating a complete vehicle battery pack or a real vehicle battery pack (in this embodiment). Figure 1 In the process, the battery pack is presented as a benchtop high-voltage power supply. The battery pack can receive DC power input from the electric drive assembly to form energy storage, and can also output DC power to the electric drive assembly as a power source.

[0047] In this embodiment, the steps for setting up the electric drive assembly durability testing system specifically include: connecting the motor controller to the charging pile end of the high-voltage power supply and the battery pack respectively; connecting the low-voltage end of the motor controller to the low-voltage power supply; connecting the output end of the motor to the electric dynamometer through a reducer; connecting the power analyzer to the motor controller, the power analyzer being used to measure the DC boost output power of the motor controller; and connecting the host computer of the test bench to the high-voltage power supply, battery pack, low-voltage power supply, motor controller, and power analyzer.

[0048] The low-voltage power supply is used as the control power supply for the motor controller, and the electric dynamometer serves as the output load for the motor.

[0049] After completing the system setup in step S101, the electric drive assembly durability test system needs to be tested initially, i.e., step S102. The test items include: peak external characteristic test, insulation resistance test and motor back electromotive force test.

[0050] Peak external characteristic test refers to: the host computer on the test bench controls the output voltage of the high voltage power supply of the test bench. The input voltage is specifically the rated operating voltage of the electric drive assembly. The voltage is set to three points: the minimum operating voltage, the rated operating voltage, and the maximum operating voltage. The peak external characteristic of the electric drive assembly is tested by a power dynamometer to determine whether the peak external characteristic of the electric drive assembly meets the pre-specified peak external characteristic requirements.

[0051] The specific process of insulation resistance testing is as follows: Connect the four-phase wires connecting the motor controller and the motor, along with the high-voltage port, to the positive terminal of the insulation withstand voltage tester. Connect all terminals of the low-voltage port in the electric drive assembly durability test system, along with the housing, to the negative terminal of the insulation withstand voltage tester. Use the insulation resistance tester to measure the insulation resistance between the high-voltage terminal of the motor controller and the housing, and use the insulation resistance tester to measure the insulation resistance between the low-voltage terminal of the motor controller and the housing. Based on the test results of the insulation withstand voltage tester, determine whether the insulation requirements of the electric drive assembly meet the pre-specified insulation requirements.

[0052] The steps for testing the back electromotive force (EMF) of a motor include: connecting the voltage probe of an oscilloscope to the U, V, and W phase lines of the motor respectively; using a dynamometer to drive the motor to its rated maximum speed at 1000 rpm intervals; and testing the back EMF of the motor's three phases using the oscilloscope to determine whether the back EMF meets the pre-specified requirements. During the test, the connection between the three-phase busbars of the motor controller and the three-phase terminals of the motor should be disconnected. The high-voltage differential probe of the oscilloscope should be connected to the U and V phases of the motor. The dynamometer should be used to drive the electric drive assembly to a certain speed, and the back EMF values ​​at the two speeds should be recorded using the oscilloscope. After the test, the connection between the three-phase busbars of the motor controller and the three-phase terminals of the motor should be restored.

[0053] The above preliminary test items are only for example purposes. The actual preliminary test items can be adjusted according to the requirements of the electric drive assembly.

[0054] Step S103 is: let the electric drive assembly stand still for a preset time T1 hours.

[0055] Specifically, before the test, the electric drive assembly needs to be fully immersed in the test environment to make the test conditions more closely resemble the surrounding environment. Therefore, T1 can be determined based on the actual situation, with the time required to achieve the desired effect as the standard.

[0056] In step S104, the host computer on the test bench controls the low-voltage power supply to power on the motor controller, and determines that the communication CAN and calibration CAN between the host computer and the electric drive assembly are normal, and the oil pump signal (this oil pump signal only exists when the electric drive assembly is an oil-cooled electric drive assembly) is normal, based on the signal sent by the electric drive assembly.

[0057] Specifically, in step S4, after the low voltage is powered on, if the communication CAN, calibration CAN signals and oil pump signals are normal, then proceed to the next test; if any signal is abnormal, then the low voltage signal needs to be checked, and the problem needs to be found and resolved.

[0058] In step S105, the host computer on the test bench controls the high voltage to be powered on and sends a DC boost charging command to the electric drive assembly to charge the battery pack. During the charging process, the voltage of the battery pack will continue to rise. The electric drive assembly adjusts the boost ratio according to the vehicle's DC boost charging strategy to charge the battery pack. The battery pack is charged to the required amount of power Q in time t2. The host computer on the test bench then sends a charge-off command to the electric drive assembly to stop charging.

[0059] If the DC boost output power measured by the power analyzer is not within the preset power range during the execution of step S105, the host computer on the test bench will output the result of failing the durability test of the electric drive assembly's drive and power generation conditions and the durability test of the electric drive assembly's DC boost charging.

[0060] Specifically, after the high voltage is applied, it is necessary to determine whether the test bench meets the DC boost requirements. The signal in the example is for reference only, and can be adjusted according to the test bench system and electric drive assembly in practice.

[0061] The required power Q and working time t2 are the actual DC boost charging time of the simulated vehicle, which can be adjusted according to the actual situation and specific needs.

[0062] In step S106, the host computer on the test bench sends a command to enter torque mode to the electric drive assembly. The electric drive assembly operates under a specific electric drive durability condition K (simulating the actual operating conditions of the vehicle) and consumes power to the DC boost charging power Q. The electric drive mileage is recorded as L1, and a command to end torque control mode is sent.

[0063] Repeat steps S5 and S6 until the total mileage of the electric drive assembly reaches the preset lifespan mileage L. This completes the durability test of the electric drive assembly's drive and power generation conditions, as well as the DC boost charging durability test. L represents the maximum lifespan required for the test and can be adjusted according to the test requirements.

[0064] Specifically, this embodiment mainly simulates the reliability verification of the electric drive vehicle after the DC boost is completed. The specific electric drive durability condition K can be customized by the enterprise as a durability drive condition or a power generation condition. In particular, this condition K can be completed in advance before the DC boost charging durability test, so this step can be simply simulated by rotating at a low speed.

[0065] In this embodiment, the test requires a back EMF test of the motor after each N-cycle of steps S5 and S6. This is mainly to check and identify the condition of the electric drive assembly and to identify risks in advance.

[0066] Step S107: Retest the electric drive assembly durability test system, same as step S102.

[0067] Specifically, the purpose of the retest is to verify whether the electric drive assembly is still functioning normally, whether the DC boost function durability test affects the normal use of the electric drive system, and whether the DC boost charging performance of the electric drive assembly has decreased.

[0068] Step S108 involves disassembling the electric drive assembly and generating a disassembly report. Specifically, disassembly involves inspecting the internal components of the electric drive assembly for damage.

[0069] This invention utilizes the aforementioned testing method to simultaneously perform DC boost charging durability testing and endurance testing of power generation and driving conditions on an electric drive assembly with DC boost charging functionality. During the DC boost charging durability test, the electric drive assembly boosts the DC power output from the high-voltage power supply on the test bench before outputting it to the battery pack, thus achieving DC boost charging of the battery pack. After the battery pack is charged, during the power generation and driving condition endurance tests, the motor in the electric drive assembly simulates the allowable operating conditions of a real vehicle by driving a power dynamometer as a load to consume the charging power from the battery pack. By cyclically performing DC boost charging of the battery pack and then consuming the charging power through the electric drive assembly, the durability testing of the electric drive assembly's DC boost charging function and the endurance testing of the drive and power generation conditions under simulated real vehicle operating conditions are simultaneously achieved. Compared to whole-vehicle verification, this significantly shortens the testing time, reduces testing resource investment, greatly improves efficiency, and lowers testing costs. Compared to manual operation, it can reduce personnel input and the risk of misoperation, improve the safety and operability of the test, speed up the bench test process, and reduce the test cost.

[0070] While only one or a few examples of the invention have been described herein, it will be apparent to those skilled in the art that the invention can be practiced in many other ways without departing from its logic and basic framework. Therefore, the invention is not intended to be limited to the embodiments described herein.

Claims

1. A durability testing method for an electric drive assembly with DC boost charging function, characterized in that, include: Step S1: Build an electric drive assembly durability testing system; Step S2: Conduct a preliminary durability test on the constructed electric drive assembly durability test system according to the predetermined test procedures; Step S3: Set the electric drive assembly durability test system to stand still for a preset time. Step S4: After completing the initial durability test, the electric drive assembly durability test system is powered on with low voltage and high voltage. Then, the electric drive assembly is controlled to simulate the vehicle's DC boost charging strategy to perform DC boost charging on the simulated bench high-voltage power supply two in the electric drive assembly durability test system. The charging amount is Q. In step S4, if the DC boost output power measured by the power analyzer is not within the preset power range, the host computer of the test bench will output the result that the electric drive assembly drive and power generation condition durability test and the electric drive assembly DC boost charging durability test have failed. Step S5: Control the electric drive assembly in the electric drive assembly durability test system to simulate the actual operating conditions of the whole vehicle, so as to consume the charging power Q of the simulated bench high voltage power supply in the electric drive assembly durability test system, and record the mileage L1 of the electric drive assembly for this test. Repeat steps S4 and S5 until the total mileage of the electric drive assembly reaches the preset life mileage L, thus completing the durability test of the electric drive assembly drive and power generation conditions and the DC boost charging durability test of the electric drive assembly. Step S6: Conduct a durability test retest on the constructed electric drive assembly durability test system according to the predetermined test procedures; Step S7: Based on the initial durability test results and the retest results of the durability test, verify whether the electric drive assembly durability test system is normal after repeating steps S4 and S5. Step S8: Disassemble the electric drive assembly durability testing system and generate a disassembly report.

2. The durability testing method for an electric drive assembly with DC boost charging function according to claim 1, characterized in that, In step S1, the electric drive assembly durability testing system includes: a bench computer, an electric drive assembly consisting of a motor controller, a motor and a reducer, a power dynamometer as the motor load, a bench high voltage power supply simulating a charging pile, a low voltage power supply, a battery pack and a power analyzer. The steps for setting up an electric drive assembly durability testing system include: The motor controller is mounted on the charging pile terminal of the high-voltage power supply and the battery pack respectively. Connect the low-voltage terminal of the motor controller to the low-voltage power supply; Connect the motor's output end to the electric dynamometer via a speed reducer; Connect the power analyzer to the motor controller. The power analyzer is used to measure the DC boost output power of the motor controller. The host computer on the test bench is used to connect to the high-voltage power supply, battery pack, low-voltage power supply, motor controller, and power analyzer on the test bench.

3. The durability testing method for an electric drive assembly with DC boost charging function according to claim 1, characterized in that, The contents of the initial durability test in step S2 and the retest of durability test in step S6 both include: Peak external characteristic test, insulation resistance test and motor back electromotive force test were performed on the electric drive assembly durability test system.

4. The durability testing method for an electric drive assembly with DC boost charging function according to claim 3, characterized in that, The steps for performing peak out-of-peak characteristic tests on an electric drive assembly durability testing system include: By controlling the minimum operating voltage, rated operating voltage, and maximum operating voltage of the two-output electric drive assembly of the high-voltage power supply on the test bench via the host computer, and measuring the peak external characteristics of the electric drive assembly using a power dynamometer, it is determined whether the peak external characteristics of the electric drive assembly meet the pre-specified peak external characteristic requirements.

5. The durability testing method for an electric drive assembly with DC boost charging function according to claim 3, characterized in that, The steps for performing insulation resistance testing on an electric drive assembly durability testing system include: Connect the four-phase wires connecting the motor controller and the motor, along with the high-voltage port, to the positive terminal of the insulation withstand voltage tester. Connect all terminals of the low-voltage port in the electric drive assembly durability test system, along with the housing, to the negative terminal of the insulation withstand voltage tester. Based on the test results of the insulation withstand voltage tester, determine whether the insulation requirements of the electric drive assembly meet the pre-specified insulation requirements.

6. The durability testing method for an electric drive assembly with DC boost charging function according to claim 3, characterized in that, The steps for performing back EMF testing on the electric drive assembly durability testing system include: Disconnect the three-phase copper busbar of the motor controller from the three-phase terminals of the motor. Connect the voltage probe of the oscilloscope to the U, V, and W phase lines of the motor respectively. Use a dynamometer to drive the motor to the rated maximum speed point at intervals of 1000 rpm. Test the back electromotive force of the motor's three phases with the oscilloscope to determine whether the back electromotive force meets the pre-specified back electromotive force requirements.

7. The durability testing method for an electric drive assembly with DC boost charging function according to claim 2, characterized in that, The battery pack is either a bench high-voltage power supply simulating a vehicle battery pack or a real vehicle battery pack.

8. The durability testing method for an electric drive assembly with DC boost charging function according to claim 1, characterized in that, In step S8, if the difference in peak external characteristic variation of the electric drive assembly durability test system in the initial test results and the retest results is within the preset variation range, the insulation resistance of the high voltage terminal to the housing and the insulation resistance of the low voltage terminal to the housing of the motor controller in the initial test results and the retest results are both within their respective preset resistance ranges, and the back electromotive force difference of the motor in the initial test results and the retest results is within the preset back electromotive force difference variation range, then it is determined that the electric drive assembly durability test system has successfully completed the predetermined number of electric drive assembly drive and power generation condition durability tests and electric drive assembly DC boost durability tests.

9. The durability testing method for an electric drive assembly with DC boost charging function according to claim 1 or 2, characterized in that, The electric drive assembly is either a water-cooled electric drive assembly or an oil-cooled electric drive assembly.

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