Electric drive system assembly efficiency test method based on temperature control

Abstract

The invention discloses an electric drive system assembly efficiency test method based on temperature control, and the method comprises the following steps: setting a test target working condition matrix of an electric drive assembly, and obtaining the no-load mechanical power at each rotating speed point; setting a test target working condition matrix of the electric drive assembly; preheating an electric drive assembly, and raising the temperature of a motor stator, the temperature of lubricating oil and the temperature of a motor rotor to specified values; respectively adjusting the output rotating speed of the load dynamometer and the output torque of the electric drive assembly to the target rotating speed and the target torque of each working condition point in the target working condition matrix; the motor stator temperature, the lubricating oil temperature and the motor rotor temperature after each target working condition point are judged; and then the electric power, the mechanical power and the electric drive assembly efficiency of the electric drive assembly located at each working condition point are obtained. The problem that various temperature parameters cannot be accurately and flexibly controlled in an existing electric drive assembly efficiency test can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive assembly testing for new energy vehicle models, and in particular to an electric drive assembly efficiency testing method capable of accurately controlling test temperature conditions. Background Art

[0002] The efficiency test of electric drive assembly is a key link in evaluating the performance of core components of electric vehicles and optimizing system design. The electric drive assembly includes motors, reducers, inverters and control systems, which are responsible for converting electrical energy into mechanical energy to drive the vehicle. With the rapid development of the electric vehicle market, consumers' requirements for driving range and energy efficiency are constantly increasing, which puts higher requirements on the efficiency of electric drive assemblies.

[0003] Traditional internal combustion engine vehicles have low efficiency and high energy waste, while electric vehicles can significantly improve overall efficiency, reduce energy consumption and emissions through efficient electric drive systems. Therefore, accurately evaluating and improving the efficiency of electric drive assemblies is crucial to improving the performance and market competitiveness of electric vehicles.

[0004] In the existing field of drive system efficiency testing, manual measurement is usually used. Engineers manually control relevant variables such as speed, torque, cooling water temperature, etc., and the data under steady-state torque and speed conditions are used as test results. This manual measurement method has very high operational requirements for test engineers. Engineers must have very good consistency at each measurement point to obtain relatively accurate results. It is relatively easy to achieve when there are fewer measurement points, but when there are more measurement points, this method not only increases the time cost sharply, but also engineers' long-term manual operation and naked eye observation will cause test errors. In fact, there are many influencing variables in the efficiency test of the electric drive assembly, especially the control requirements for the motor stator temperature, motor rotor temperature and lubricating oil temperature are very high. If the control is not precise, the efficiency test results will be inaccurate. Summary of the invention

[0005] The present invention provides an electric drive assembly efficiency testing method capable of accurately controlling test temperature conditions, which can solve the problem that various temperature parameters in the existing electric drive assembly efficiency test cannot be accurately and flexibly controlled, and improves the repeatability of the test.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical methods: a method for testing the efficiency of an electric drive system assembly based on temperature control, comprising an electric drive assembly, at least one load dynamometer, a battery simulator, a power analyzer, a speed sensor, a torque sensor and a data acquisition system, wherein the output end of the battery simulator is connected to the high-voltage wiring harness end of the electric drive assembly, and the high-voltage wiring harness end of the electric drive assembly is provided with a current sensor and a voltage sensor, wherein the current sensor is used to measure the current of the electric drive assembly in real time and transmit it to the power analyzer, and the voltage sensor is used to measure the voltage of the electric drive assembly in real time and transmit it to the power analyzer, and the power analyzer is used to calculate the electric power of the electric drive assembly according to the current and voltage of the electric drive assembly and send it to the data acquisition system, and the speed sensor and the torque sensor are installed on the load dynamometer, and are respectively used to measure the output torque and output speed of the electric drive assembly in real time and send them to the data acquisition system, and the data acquisition system is used to calculate the mechanical power of the electric drive assembly and store the electric power of the electric drive assembly in real time;

[0007] Conduct efficiency test:

[0008] S1. Set the test target operating condition matrix of the electric drive assembly, which includes multiple different motor speeds Ni and the same target torque of 0; obtain the mechanical power at each speed point. This step mainly measures the mechanical loss of the dynamometer bench and calculates the mechanical power at different speeds. The mechanical power calculation formula is: T is the wheel end no-load torque of the load dynamometer, and N is the wheel end speed of the load dynamometer;

[0009] S2. Set the test target operating condition matrix of the electric drive assembly, which includes multiple different motor speeds Ni and multiple different target torques Tj. There is a one-to-many mapping relationship between the target speed Ni and the target torque Tj. Each operating point includes a target speed and a target torque Tj corresponding to the target speed Ni. The driving mechanical power

[0010] S3, the electric drive assembly is preheated, and the load dynamometer outputs the speed N h , electric drive assembly output torque T h , heat the motor stator temperature to Tm, the lubricating oil temperature to To, and the motor rotor temperature to Tz;

[0011] S4, adjusting the output speed of the load dynamometer and the output torque of the electric drive assembly to the target speed Ni and target torque Tj of each operating point in the target operating condition matrix, respectively, and running for 3-5 seconds;

[0012] S5. Determine the motor stator temperature, lubricating oil temperature and motor rotor temperature after each target operating point is completed in step S4. When the motor stator temperature is within Tm±a, the lubricating oil temperature is within To±b, and the motor rotor temperature is within Tz±c, run the next operating point. When the motor stator temperature is less than Tm-a or the lubricating oil temperature is less than To-b or the motor rotor temperature is at Tz-c, perform step S3 to heat the motor. When the motor stator temperature is greater than Tm+a or the lubricating oil temperature is greater than To+b or the motor rotor temperature is at Tz+c, set the load dynamometer speed to 0, the electric drive assembly torque to 0, and perform cooling.

[0013] S6. For the electric drive assembly at each operating point, the electric power PE, mechanical power PM and efficiency of the electric drive assembly are obtained respectively. The efficiency of the electric drive assembly is the difference between the driving mechanical power PM and the no-load mechanical power PN divided by the electric power PE, that is, The feeding efficiency is the electric power PE divided by the difference between the feeding mechanical power PM and the no-load mechanical power PN, that is,

[0014] S7. Different torques Tj corresponding to different speeds Si have corresponding efficiencies, which are displayed as a color scale MAP diagram of the electric drive assembly efficiency.

[0015] Furthermore, when measuring the mechanical loss of the load dynamometer in step S1, the average value of the three sets of data is taken for calculation, that is, PN1, PN2 and PN3 are the mechanical powers in the three sets of data respectively.

[0016] Furthermore, when calculating the driving mechanical power PM in step S2, the mechanical power of three sets of data is taken after stable operation at each operating point, that is, PM1, PM2 and PM3 are the mechanical powers of three sets of data respectively.

[0017] Furthermore, in step S3, when the motor stator temperature is increased, the electric drive assembly operates under the condition of low output speed and high output torque; when the motor rotor temperature is increased, the electric drive assembly operates under the condition of high output speed and low output torque; when the lubricating oil temperature is increased, the electric drive assembly operates under the condition of medium output speed and medium output torque.

[0018] Furthermore, when the efficiency of the electric drive system is tested in step S4, the speed of the electric drive assembly test condition changes from low to high, and the rotational torque changes from low to high.

[0019] Preferably, in the electric drive system efficiency test of steps S4 and S5, when the test speed is 500-6000rpm and the test rotation torque is 5Nm-100Nm, the test is started when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm+1. After each operating point is measured, the temperature is determined. When the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-3 to Tm+5, the test is continued;

[0020] When the test speed is 500-6000rpm and the test rotation torque is 100-250Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. When the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-5 to Tm+3, the test continues.

[0021] When the test speed is 500-6000rpm and the test rotation torque is 260-400Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-5 to Tm+1.

[0022] When the test speed is 6500-10000rpm and the test rotation torque is 5Nm-50Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm+1. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-3 to Tm+5.

[0023] When the test speed is 6500-10000rpm and the test rotation torque is 55-100Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-5 to Tm+3.

[0024] When the test speed is 6500-10000rpm and the test rotation torque is 110-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-5 to Tm+1.

[0025] When the test speed is 10500rpm-SMax and the test rotation torque is 5Nm-50Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm+1. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-3 to Tm+3.

[0026] When the test speed is 10500rpm-SMax and the test rotation torque is 55-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-5 to Tm+1.

[0027] In other cases, if the temperature is below the range, the machine is heated up, and if the temperature is above the range, the machine is cooled down.

[0028] Furthermore, it also includes an environmental chamber, in which the electric drive assembly is installed, and the environmental chamber provides a constant temperature environment for the electric drive assembly.

[0029] Furthermore, there are two load dynamometers, which are respectively arranged on both sides of the electric drive assembly and connected to the electric drive assembly through a transmission half shaft.

[0030] Preferably, one end of the transmission half shaft is connected to the electric drive assembly, and the other end is connected to the hub flange, the hub flange is connected to the flange plate, the flange plate is connected to the output end of the load dynamometer, and the torque sensor is connected to the flange plate.

[0031] Preferably, the electric drive assembly is installed on a drive assembly test bench, and a control system is also installed on the drive assembly test bench for controlling two load dynamometers to run at a preset speed, thereby achieving control of the speed of the electric drive assembly. When the output torque of the electric drive assembly increases, the load dynamometer uses AC frequency conversion to adjust the loading torque in real time.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) A simple and reliable test system can be used to test the efficiency of various types of electric drive assemblies. During the test, the motor stator temperature, motor rotor temperature, and lubricating oil temperature can be controlled simultaneously, so that the efficiency of the electric drive assembly system can be accurately evaluated under the test state, the repeatability of the test can be improved, and the overall performance of the electric drive assembly can be effectively evaluated;

[0034] (2) During the test, the speed is controlled from low to high and the torque is controlled from low to high. Different temperature control strategies are used in different speed and torque ranges, so that as many test conditions as possible can be found within each temperature range, thereby improving the test efficiency. In addition, by controlling the temperature range, the temperature of the next condition will not exceed the control range due to the inertia of the temperature rise of the previous condition, thereby ensuring the accuracy of the test.

[0035] (3) No-load torque detection and no-load mechanical loss are added during the test process. When actually calculating the test condition efficiency, the no-load power loss should be added to obtain a more accurate electric drive efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The overall structure diagram of the electric drive system assembly efficiency test system of the present invention;

[0037] Figure 2 is a flow chart of the testing method of the present invention;

[0038] Figure 3 It is a control logic diagram of the motor stator temperature, lubricating oil temperature and motor rotor temperature of the present invention;

[0039] Figure 4 It is a color scale MAP diagram of the electric drive assembly efficiency of the present invention.

[0040] Reference numerals:

[0041] 1. Load dynamometer, 2. Current sensor, 3. Battery simulator, 4. Voltage sensor, 5. Power analyzer, 6. Data acquisition system, 7. Speed ​​sensor, 8. Torque sensor, 9. Electric drive assembly, 10. Environmental chamber. DETAILED DESCRIPTION

[0042] The technical method in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

[0043] like Figure 1-4As shown, the present invention solves the problem that various temperature parameters in the existing electric drive assembly efficiency test cannot be accurately and flexibly controlled and improves the repeatability of the test. The present invention provides the following technical methods: a method for testing the efficiency of an electric drive system assembly based on temperature control, comprising an electric drive assembly 9, at least one load dynamometer 1, a battery simulator 3, a power analyzer 5, a speed sensor 7, a torque sensor 8 and a data acquisition system 6, wherein the output end of the battery simulator 3 is connected to the high-voltage wiring harness end of the electric drive assembly 9, and the high-voltage wiring harness end of the electric drive assembly 9 is provided with a current sensor 2 and a voltage sensor 4, and the current sensor 2 is used to measure in real time The current of the electric drive assembly 9 is transmitted to the power analyzer 5, the voltage sensor 4 is used to measure the voltage of the electric drive assembly 9 in real time and transmit it to the power analyzer 5, the power analyzer 5 is used to calculate the electric power of the electric drive assembly 9 according to the current and voltage of the electric drive assembly 9 and send it to the data acquisition system 6, the speed sensor 7 and the torque sensor 8 are installed on the load dynamometer 1, respectively, for measuring the output torque and output speed of the electric drive assembly 9 in real time and sending them to the data acquisition system 6, the data acquisition system 6 is used to calculate the mechanical power of the electric drive assembly 9 and store the electric power of the electric drive assembly in real time, wherein, Figure 1 As shown, the test system of this embodiment also includes an environmental chamber 10. The electric drive assembly 9 is installed in the environmental chamber 10. The environmental chamber 10 provides a constant temperature environment for the electric drive assembly 9, which is conducive to simulating the efficiency test of the electric drive assembly 9 at different temperatures.

[0044] The power analyzer 5 is electrically connected to the current sensor 2 and the voltage sensor 4 , and the data acquisition system 6 is communicatively connected to the rotation speed sensor 7 , the torque sensor 8 and the power analyzer 5 , respectively.

[0045] The electric drive assembly 9 is installed on a drive assembly test bench, and a control system is also installed on the drive assembly test bench for controlling the two load dynamometers 1 to run at a preset speed, thereby realizing the control of the speed of the electric drive assembly 9. When the output torque of the electric drive assembly 9 increases, the load dynamometer 1 adopts AC frequency conversion to adjust the loading torque in real time. The drive assembly test bench adopts the electric drive assembly test bench produced by HORI BA of Japan. The existing technology is mature and its specific structure is not repeated here.

[0046] In this embodiment, there are two load dynamometers 1, which are respectively arranged on both sides of the electric drive assembly 9 and are connected to the electric drive assembly 9 through a transmission half shaft. The two load dynamometers 1 are used to simulate the two front wheels or the two rear wheels of the car. The output speed of the load dynamometer 1 is the same as the output speed of the electric drive assembly 9. This setting can better simulate the daily driving conditions of the car.

[0047] In order to ensure the test accuracy of the output speed and output torque of the electric drive assembly 9, one end of the transmission half shaft is connected to the electric drive assembly 9, and the other end is connected to the hub flange, the hub flange is connected to the flange plate, the flange plate is connected to the output end of the load dynamometer 1, and the torque sensor 8 is connected to the flange plate. The torque sensor 8 can test the actual torque generated during transmission between the hub flange and the flange plate.

[0048] In this embodiment, as an actual testing method, the following steps are included:

[0049] S1. Set the test target operating condition matrix of the electric drive assembly 9, which includes multiple different motor speeds Ni and the same target torque of 0; obtain the mechanical power at each speed point. This step mainly measures the mechanical loss of the dynamometer bench and calculates the mechanical power at different speeds. The mechanical power calculation formula is: T is the wheel end no-load torque of the load dynamometer 1, N is the wheel end speed of the load dynamometer 1. In the no-load test, the rotation torque of the load dynamometer 1 is 0. When measuring the mechanical loss of the load dynamometer 1, the average value of the three sets of data is taken for calculation, that is, PN1, PN2, and PN3 are the mechanical powers in the three sets of data respectively. The obtained PN is the no-load mechanical power. When actually calculating the efficiency of the test condition, the no-load power loss should be added to obtain a more accurate electric drive efficiency.

[0050] S2. Set the test target operating condition matrix of the electric drive assembly, which includes multiple different motor speeds Ni and multiple different target torques Tj. There is a one-to-many mapping relationship between the target speed Ni and the target torque Tj. Each operating point includes a target speed and a target torque Tj corresponding to the target speed Ni. The driving mechanical power Similarly, when calculating the driving mechanical power PM, the mechanical power of three sets of data is taken after stable operation at each operating point, that is, the driving mechanical power PM1, PM2, and PM3 are the mechanical powers of three sets of data respectively. PM1, PM2, and PM3 here all need to be obtained after stable operation for 3-5 seconds at the corresponding operating point;

[0051] S3, the electric drive assembly 9 is preheated, and the load dynamometer 1 outputs the speed N h , the electric drive assembly 9 outputs torque T h, heat the motor stator temperature to Tm, the lubricating oil temperature to To, and the motor rotor temperature to Tz. When the motor stator temperature is increased, the electric drive assembly 9 operates under the condition of low output speed and high output torque; when the motor rotor temperature is increased, the electric drive assembly 9 operates under the condition of high output speed and low output torque; when the lubricating oil temperature is increased, the electric drive assembly 9 operates under the condition of medium output speed and medium output torque. For different motors, the rated ranges of output speed and output torque can be divided into three intervals of low, medium and high from small to large, such as low, medium and high speed intervals of 500-6000rpm, 6500-10000rpm and 10500-SMax, respectively, and low, medium and high output torque intervals of 5Nm-100Nm, 100-250Nm and 250-TMax, respectively;

[0052] S4. Adjust the output speed of the load dynamometer 1 and the output torque of the electric drive assembly 9 to the target speed Ni and target torque Tj of each operating point in the target operating condition matrix, respectively, and run for 3-5s. When testing the efficiency of the electric drive system, the motor stator temperature is greatly affected by the water cooling system, and its temperature changes faster, while the lubricating oil temperature and the motor rotor temperature change slowly. Because the motor stator temperature is greatly affected by the rotational torque, in order to make the test smoother and improve the efficiency, the test operating speed of the electric drive assembly 9 is changed from low to high, and the rotational torque is changed from low to high. Specifically, the speed can be increased in steps of 500rpm, such as 500rpm, 1000rpm, 1500rpm...SMax, and the rotational torque can be increased in steps of 5Nm, such as 5Nm, 10Nm...95Nm, 100Nm, 110Nm...Tmax. The motor speed has a climbing capacity of 1000rpm / s, and the rotational torque rises to the target torque in 1s.

[0053] S5, this step is performed simultaneously with step S4, and the motor stator temperature, lubricating oil temperature and motor rotor temperature after each target operating point in step S4 are completed are determined. When the motor stator temperature is within Tm±a, the lubricating oil temperature is within To±b, and the motor rotor temperature is within Tz±c, the next operating point is operated. When the motor stator temperature is less than Tm-a or the lubricating oil temperature is less than To-b or the motor rotor temperature is at Tz-c, step S3 is performed to heat the motor. When the motor stator temperature is greater than Tm+a or the lubricating oil temperature is greater than To+b or the motor rotor temperature is at Tz+c, the speed of the load dynamometer 1 is set to 0, the torque of the electric drive assembly 9 is 0, and the motor is cooled.

[0054] Specifically, in the electric drive system efficiency test in steps S4 and S5, when the test speed is 500-6000rpm, the test rotational torque is 5Nm-100Nm, the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm+1, the test is started. For example, the lubricating oil temperature is 63°C, the motor rotor temperature is 63°C, and the motor stator temperature is 86°C. The test is started because when the low-speed and low-torque operating point is tested, the power is low, and the low torque is not enough to increase the stator temperature. On the contrary, the stator temperature drops due to the cooling of the cooling system. Therefore, when testing at low speed and low torque, the motor stator temperature at the beginning of the test should be higher. Then, as many test points as possible can be tested within the appropriate temperature range to improve the test efficiency. After each test point is completed, the temperature is determined. The test is continued when the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-3 to Tm+5. For example, the rotor temperature is 60-66℃, the oil temperature is 60-66℃, and the stator temperature is 82-90℃.

[0055] When the test speed is 500-6000rpm and the test torque is 100-250Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. For example, when the lubricating oil temperature is 63℃, the motor rotor temperature is 63℃, and the motor stator temperature is 80℃, the temperature is determined after each operating point is measured. If the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-5 to Tm+3, the test continues. Test, the upper temperature range of the motor stator temperature within this operating point range is lower, because the rotor and lubricating oil are not greatly affected by the torque, and the temperature may drop, while the motor stator temperature may continue to rise due to the influence of the previous operating condition. If the upper temperature of the motor stator temperature is set at 90℃, the inertia of temperature change may cause the next operating point to be out of the test temperature range, affecting the accuracy of the test. For example, the rotor temperature is 60-66℃, the oil temperature is 60-66℃, and the stator temperature is 80-88℃. Continue to test;

[0056] When the test speed is 500-6000rpm and the test rotation torque is 260-400Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. For example, the lubricating oil temperature is 63℃, the motor rotor temperature is 63℃, and the motor stator temperature is 80℃. After each working point is measured, the temperature is determined. The test is continued when the lubricating oil temperature is in the range of To-3 to To+3, the motor rotor temperature is in the range of Tz-3 to Tz+3, and the motor stator temperature is in the range of Tm-5 to Tm+1. Similarly, the rotation torque is relatively large in this test working condition range, and the upper temperature of the motor stator temperature needs to be limited. For example, the rotor temperature is 60-66℃, the oil temperature is 60-66℃, and the stator temperature is 80-86℃.

[0057] When the test speed is 6500-10000rpm and the test torque is 5Nm-50Nm, because the speed can keep the rotor temperature stable during the medium speed and low torque test, the rotor and oil temperature are not greatly affected by the torque during the speed climbing process. The stator temperature drops under the influence of the cooling system because there is no torque support. Therefore, when testing at medium speed and low torque, the motor stator temperature at the beginning of the test should be higher. In this way, as many test points as possible can be tested within the appropriate temperature range to improve the test efficiency. The lubricating oil temperature reaches To-3, electric The test starts when the rotor temperature reaches Tz-3 and the stator temperature reaches Tm+1. For example, the lubricating oil temperature is 60℃, the motor rotor temperature is 60℃, and the motor stator temperature is 86℃. After each working point is measured, the temperature is determined. If the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-3 to Tm+5, the test will continue. For example, if the rotor temperature is 60-64℃, the oil temperature is 60-64℃, and the stator temperature is 82-90℃, the test will continue.

[0058] When the test speed is 6500-10000rpm and the test rotation torque is 55-100Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. For example, the lubricating oil temperature is 60℃, the motor rotor temperature is 60℃, and the motor stator temperature is 80℃. After each working point is measured, the temperature is determined. The test is continued when the lubricating oil temperature is in the range of To-3 to To+2, the motor rotor temperature is in the range of Tz-3 to Tz+2, and the motor stator temperature is in the range of Tm-5 to Tm+3. Similarly, the rotation torque is relatively large in this test working condition range, and the upper temperature of the motor stator temperature needs to be limited. For example, the rotor temperature is 60-64℃, the oil temperature is 60-64℃, and the stator temperature is 80-88℃.

[0059] When the test speed is 6500-10000rpm and the test rotation torque is 110-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. For example, the lubricating oil temperature is 60℃, the motor rotor temperature is 60℃, and the motor stator temperature is 80℃. After each working point is measured, the temperature is determined. The test is continued when the lubricating oil temperature is in the range of To-3 to To+2, the motor rotor temperature is in the range of Tz-3 to Tz+2, and the motor stator temperature is in the range of Tm-5 to Tm+1. Similarly, the rotation torque is relatively large in this test working condition range, and the upper temperature of the motor stator temperature needs to be limited. For example, the rotor temperature is 60-64℃, the oil temperature is 60-64℃, and the stator temperature is 80-86℃.

[0060] When the test speed is 10500rpm-SMax and the test torque is 5Nm-50Nm, because the high speed and low torque operating point test, the speed climbs to the target speed for more than 10s at high speed. During this climbing time, the stator temperature will drop because there is no loading torque or the loading torque is small. Therefore, when the high speed and low torque test is performed, the motor temperature at the beginning of the test should be higher. In this way, as many test operating points as possible can be tested within the appropriate temperature range to improve the test efficiency. The lubricating oil temperature reaches To-3 and the motor speed is The test starts when the motor temperature reaches Tz-3 and the motor stator temperature reaches Tm+1. For example, the lubricating oil temperature is 60℃, the motor rotor temperature is 60℃, and the motor stator temperature is 86℃. After each working point is measured, the temperature is determined. If the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-3 to Tm+3, the test will continue. For example, if the rotor temperature is 60-63℃, the oil temperature is 60-63℃, and the stator temperature is 82-88℃, the test will continue.

[0061] When the test speed is 10500rpm-SMax and the test rotation torque is 55-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. For example, the lubricating oil temperature is 60℃, the motor rotor temperature is 60℃, and the motor stator temperature is 80℃. After each working point is measured, the temperature is determined. If the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-5 to Tm+1, the test is continued. For example, if the rotor temperature is 60-63℃, the oil temperature is 60-63℃, and the stator temperature is 80-86℃, the test is continued.

[0062] In other cases of the above test conditions, if the control temperature is lower than the range, the machine is heated up, and if the temperature is higher than the range, the machine is cooled down.

[0063] S6. For the electric drive assembly 9 at each operating point, the electric power PE, mechanical power PM and efficiency of the electric drive assembly are obtained respectively. The efficiency of the electric drive assembly is the difference between the driving mechanical power PM and the no-load mechanical power PN divided by the electric power PE, that is, The feeding efficiency is the electric power PE divided by the difference between the feeding mechanical power PM and the no-load mechanical power PN, that is, Specifically, when the output torque of the electric drive assembly 9 is positive torque, the electric drive assembly is in a driving condition, and the working efficiency of the electric drive assembly under the driving condition is the driving state efficiency; the driving state efficiency is equal to the percentage of the quotient of the mechanical power of the electric drive assembly divided by the electric power; when the output torque of the electric drive assembly 9 is negative torque, the electric drive assembly is in a feeding condition, and the working efficiency of the electric drive assembly under the feeding condition is the feeding state efficiency; the feeding state efficiency is equal to the percentage of the quotient of the electric power of the electric drive assembly divided by the mechanical power.

[0064] S7. For different torques Tj corresponding to different speeds Si, there are corresponding efficiencies, which are displayed as a color scale MAP diagram of the electric drive assembly efficiency, such as Figure 4 As shown, the darker area in the middle is the area with relatively high efficiency of the electric drive assembly, that is, the speed is 5000-12000rpm, and the rotational torque is in the range of 40-300Nm. The car's electric drive assembly is most efficient when working in this range.

[0065] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0066] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In addition, the technical methods of the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical methods is contradictory or cannot be implemented, it should be deemed that such combination of technical methods does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for testing the efficiency of an electric drive system assembly based on temperature control, comprising an electric drive assembly (9), at least one load dynamometer (1), a battery simulator (3), a power analyzer (5), a speed sensor (7), a torque sensor (8) and a data acquisition system (6), characterized in that: The output end of the battery simulator (3) is connected to the high-voltage wiring harness end of the electric drive assembly (9), and the high-voltage wiring harness end of the electric drive assembly (9) is provided with a current sensor (2) and a voltage sensor (4). The current sensor (2) is used to measure the current of the electric drive assembly (9) in real time and transmit it to the power analyzer (5). The voltage sensor (4) is used to measure the voltage of the electric drive assembly (9) in real time and transmit it to the power analyzer (5). The power analyzer (5) is used to calculate the electric power of the electric drive assembly (9) according to the current and voltage of the electric drive assembly (9) and send it to the data acquisition system (6). The speed sensor (7) and the torque sensor (8) are installed on the load dynamometer (1), and are used to measure the output torque and output speed of the electric drive assembly (9) in real time and send them to the data acquisition system (6). The data acquisition system (6) is used to calculate the mechanical power of the electric drive assembly (9) and store the electric power of the electric drive assembly in real time. Conduct efficiency test: S1. Setting the test target operating condition matrix of the electric drive assembly (9), the test operating condition matrix includes a plurality of different motor speeds Ni and the same target torque of 0; obtaining the mechanical power at each speed point. This step mainly measures the mechanical loss of the dynamometer bench and calculates the mechanical power at different speeds. The mechanical power calculation formula is: T is the wheel end no-load torque of the load dynamometer (1), and N is the wheel end speed of the load dynamometer (1); S2. Set the test target operating condition matrix of the electric drive assembly. The test operating condition matrix includes multiple different motor speeds Ni and multiple different target torques Tj. There is a one-to-many mapping relationship between the target speed Ni and the target torque Tj. Each operating condition includes a target speed and a target torque Tj corresponding to the target speed Ni. The driving mechanical power S3, the electric drive assembly (9) is preheated, and the load dynamometer (1) outputs a speed N h , the electric drive assembly (9) outputs a torque T h , heat the motor stator temperature to Tm, the lubricating oil temperature to To, and the motor rotor temperature to Tz; S4, adjusting the output speed of the load dynamometer (1) and the output torque of the electric drive assembly (9) to the target speed Ni and target torque Tj of each operating point in the target operating matrix, respectively, and running for 3-5 seconds; S5, after completing each target operating point in step S4, the motor stator temperature, lubricating oil temperature and motor rotor temperature are determined. When the motor stator temperature is within Tm±a, the lubricating oil temperature is within To±b and the motor rotor temperature is within Tz±c, the next operating point is operated. When the motor stator temperature is less than Tm-a or the lubricating oil temperature is less than To-b or the motor rotor temperature is at Tz-c, step S3 is performed to heat the motor. When the motor stator temperature is greater than Tm+a or the lubricating oil temperature is greater than To+b or the motor rotor temperature is at Tz+c, the speed of the load dynamometer (1) is set to 0, the torque of the electric drive assembly (9) is set to 0, and the motor is cooled. S6. For the electric drive assembly (9) at each operating point, the electric power PE, mechanical power PM and efficiency of the electric drive assembly are obtained respectively. The efficiency of the electric drive assembly is the difference between the driving mechanical power PM and the no-load mechanical power PN divided by the electric power PE, that is, The feeding efficiency is the electric power PE divided by the difference between the feeding mechanical power PM and the no-load mechanical power PN, that is, S7. Different torques Tj corresponding to different speeds Si have corresponding efficiencies, which are displayed as a color scale MAP diagram of the electric drive assembly efficiency.

2. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 1, characterized in that: When measuring the mechanical loss of the load dynamometer (1) in step S1, the average value of the three sets of data is calculated, that is, PN1, PN2 and PN3 are the mechanical powers in the three sets of data respectively.

3. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 2, characterized in that: In step S2, when calculating the driving mechanical power PM, the mechanical power of three sets of data is taken after stable operation at each operating point, that is, PM1, PM2 and PM3 are the mechanical powers of three sets of data respectively.

4. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 1, characterized in that: When the motor stator temperature is increased in step S3, the electric drive assembly (9) operates under the condition of low output speed and high output torque; when the motor rotor temperature is increased, the electric drive assembly (9) operates under the condition of high output speed and low output torque; when the lubricating oil temperature is increased, the electric drive assembly (9) operates under the condition of medium output speed and medium output torque.

5. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 4, characterized in that: When testing the efficiency of the electric drive system in step S4, the electric drive assembly (9) changes its test operating speed from low to high and its rotational torque from low to high.

6. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 5, characterized in that: In the electric drive system efficiency test of steps S4 and S5, when the test speed is 500-6000rpm and the test rotation torque is 5Nm-100Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm+1. After each operating point is measured, the temperature is determined. When the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-3 to Tm+5, the test is continued. When the test speed is 500-6000rpm and the test rotation torque is 100-250Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. When the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-5 to Tm+3, the test continues. When the test speed is 500-6000rpm and the test rotation torque is 260-400Nm, the test starts when the lubricating oil temperature reaches To, the motor rotor temperature reaches Tz, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+3, the motor rotor temperature is within the range of Tz-3 to Tz+3, and the motor stator temperature is within the range of Tm-5 to Tm+1. When the test speed is 6500-10000rpm and the test rotation torque is 5Nm-50Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm+1. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-3 to Tm+5. When the test speed is 6500-10000rpm and the test rotation torque is 55-100Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-5 to Tm+3. When the test speed is 6500-10000rpm and the test rotation torque is 110-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To+2, the motor rotor temperature is within the range of Tz-3 to Tz+2, and the motor stator temperature is within the range of Tm-5 to Tm+1. When the test speed is 10500rpm-SMax and the test rotation torque is 5Nm-50Nm, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm+1. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-3 to Tm+3. When the test speed is 10500rpm-SMax and the test rotation torque is 55-TMax, the test starts when the lubricating oil temperature reaches To-3, the motor rotor temperature reaches Tz-3, and the motor stator temperature reaches Tm-5. After each working point is measured, the temperature is determined. The test continues when the lubricating oil temperature is within the range of To-3 to To, the motor rotor temperature is within the range of Tz-3 to Tz, and the motor stator temperature is within the range of Tm-5 to Tm+1. In other cases, if the temperature is below the range, the machine is heated up, and if the temperature is above the range, the machine is cooled down.

7. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 1, characterized in that: It also includes an environmental chamber (10), in which the electric drive assembly (9) is installed, and the environmental chamber (10) provides a constant temperature environment for the electric drive assembly (9).

8. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 7, characterized in that: There are two load dynamometers (1), which are respectively arranged on both sides of the electric drive assembly (9) and connected to the electric drive assembly (9) via a transmission half shaft.

9. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 8, characterized in that: One end of the transmission half shaft is connected to the electric drive assembly (9), and the other end is connected to the hub flange, the hub flange is connected to the flange plate, the flange plate is connected to the output end of the load dynamometer (1), and the torque sensor (8) is connected to the flange plate.

10. The method for testing the efficiency of an electric drive system assembly based on temperature control according to claim 8, characterized in that: The electric drive assembly (9) is mounted on a drive assembly bench. A control system is also mounted on the drive assembly bench for controlling the two load dynamometers (1) to run at a preset rotational speed, thereby realizing the control of the rotational speed of the electric drive assembly (9). When the output torque of the electric drive assembly (9) increases, the load dynamometer (1) uses AC frequency conversion to adjust the loading torque in real time.

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