Method for testing small torque of vehicle-mounted motor

Abstract

The invention relates to a method for testing the small torque of a vehicle-mounted motor. The method comprises the following steps: S1, calibrating a torque sensor; s2, small torque treatment; s3, installing the tested motor; s4, carrying out no-load test; s5, connecting a data acquisition system; s6, connecting a battery simulator; s7, testing data; and S8, data processing. According to the invention, the small-torque dynamometer is directly butted with the tested motor, so that the intermediate transmission of the axle box is reduced, the power and torque of the dynamometer are reduced, the inertia is reduced, the shaft loss of torque measurement is reduced, the range of the torque sensor is reduced, and the measurement precision is improved; the testing method can effectively solve factors such as insufficient testing precision of small torque and too large error caused by mechanical loss.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle-mounted motor testing, and in particular to a method for testing small torque of a vehicle-mounted motor. Background Art

[0002] With the development of electric vehicles and hybrid vehicles, the performance of on-board motors has a significant impact on the power and economy of the vehicle. In the bench test process of existing on-board motors, some data test inaccuracies are inevitable, especially in the small torque (below 20Nm) test, the error is more obvious, resulting in a small torque measurement result and a small calculated motor efficiency. Therefore, it is necessary to design a small torque test method for on-board motors to solve the above problems. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for testing the small torque of a vehicle-mounted motor, so as to solve the problem of inaccurate test data of the vehicle-mounted motor within the small torque range. This test method can effectively solve factors such as insufficient accuracy in testing small torque and too large errors caused by mechanical losses.

[0004] The technical solution adopted by the present invention to solve the technical problem is: to provide a method for testing the small torque of a vehicle-mounted motor, the testing method comprising the following steps:

[0005] S1. Torque sensor calibration:

[0006] A torque sensor is set on the output shaft of the small torque dynamometer. The information data detected by the torque sensor is transmitted to the RT real-time system. A frequency converter is set between the RT real-time system and the small torque dynamometer. Calibration arms are installed on both sides of the output shaft of the small torque dynamometer to ensure left-right balance and torque display is 0. The torque value is calibrated by adding weights to the calibration arms to ensure the accuracy of subsequent torque measurements. After the calibration is completed, the calibration arms and weights are removed;

[0007] S2, small torque processing:

[0008] The actual torque is calculated using the computing power of the RT real-time system. The actual torque is T1, where T1 = (F-60000) / 30000*50, and F is the output frequency of the torque sensor.

[0009] S3. Installation of the motor under test:

[0010] An L-shaped bracket is provided on one side of the small torque dynamometer, and the motor to be tested is fixed on the L-shaped bracket. A spline flange is provided on the end of the output shaft of the small torque dynamometer, and then the motor shaft of the motor to be tested is connected to the spline flange;

[0011] S4, no-load test:

[0012] Input the target speed in sequence, and use the torque sensor to measure the corresponding no-load loss torque T2 and the corresponding motor speed N at different speeds;

[0013] S5, data acquisition system connection:

[0014] Connect the motor under test to the voltage acquisition line and current sensor of the data acquisition system; the data acquisition system is used to collect the data required for the test: voltage, current and power;

[0015] S6. Battery simulator connection:

[0016] The motor under test is connected to the controller through a three-phase high-voltage line. The controller controls the torque of the motor under test. The battery simulator is connected to the controller at one end of the motor under test through a high-voltage wire harness to realize power supply. The controller and the RT real-time system are connected by a low-voltage line to realize control output.

[0017] S7, data test:

[0018] The RT real-time system adjusts the small torque dynamometer to the required speed point through the frequency converter, and then loads the small torque of the motor under test in sequence. The small torques are 2Nm, 4Nm, 6Nm, 8Nm, 10Nm, 12Nm, 14Nm, 16Nm, 18Nm and 20Nm, and the corresponding N and T1 and controller power P1 are tested in turn;

[0019] S8. Data processing:

[0020] In the electric state, the controller gives the motor under test power: T = T1-T2, P = N*(T1-T2) / 9550, η = N*(T1-T2) / 9550 / P1*100; in the generating state, the motor under test gives the controller power: η = P1 / P*100; where T is the motor torque, P is the motor power, and η is the motor efficiency.

[0021] As a supplement to the technical solution described in the present invention, the rated torque of the small torque dynamometer is 50Nm and the rated power is 50KW.

[0022] As a supplement to the technical solution described in the present invention, the measuring range of the torque sensor is 50Nm.

[0023] As a supplement to the technical solution described in the present invention, a water cooling system is also included, and the water cooling system is used to provide cooling for the motor under test.

[0024] As a supplement to the technical solution described in the present invention, a host computer is also included, and the host computer is connected to the RT real-time system and the data acquisition system respectively.

[0025] As a supplement to the technical solution described in the present invention, the output frequency of the torque sensor is 30khz-90khz.

[0026] Beneficial effects: The present invention relates to a method for testing the small torque of a vehicle-mounted motor, which adopts a small torque dynamometer to directly connect with the motor to be tested, thereby reducing the intermediate transmission of the axle box, reducing the power and torque of the dynamometer, reducing the inertia, reducing the shaft loss of measuring torque, reducing the range of the torque sensor, and increasing the measurement accuracy. This testing method can effectively solve the factors such as insufficient accuracy in testing small torque and too large errors caused by mechanical losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Diagram: 1. Small torque dynamometer, 2. RT real-time system, 3. Motor under test, 4. L-shaped bracket, 5. Torque sensor, 6. Data acquisition system, 7. Battery simulator, 8. Water cooling system, 9. Host computer, 10. Frequency converter. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0030] The embodiment of the present invention relates to a method for testing a small torque of a vehicle-mounted motor, such as Figure 1 As shown, the test method comprises the following steps:

[0031] S1. Torque sensor calibration:

[0032] A torque sensor 5 is provided on the output shaft of the small torque dynamometer 1. The information data detected by the torque sensor 5 is transmitted to the RT real-time system 2. A frequency converter 10 is provided between the RT real-time system 2 and the small torque dynamometer 1. The frequency converter 10 is an electric energy control device that converts the industrial frequency power supply into another frequency by using the on-off function of the power semiconductor device. The calibration arms are installed on both sides of the output shaft of the small torque dynamometer 1 to ensure the left and right balance and the torque display is 0. The torque value is calibrated by adding weights to the calibration arms to ensure the accuracy of the subsequent torque measurement. After the calibration is completed, the calibration arms and weights are removed;

[0033] S2, small torque processing:

[0034] Using RT real-time system 2, the sampling rate of torque frequency is higher, the calculated data is not distorted, and the data collected by the software is more accurate. The embedded Compact Rio controller Crio-9041 with 25 nanosecond high-speed digital I / O and frequency measurement capabilities and corresponding reconfigurable FPGA internal logic processing capabilities is used, combined with the NI9401 eight-channel 5V / TTL high-speed bidirectional digital I / O module, for the torque sensor 5 with higher time resolution, 30khz-90khz corresponds to (-50N·m~50N·m) The frequency acquisition provides higher sampling accuracy. LabVIEW FPGA can directly map the algorithm and application logic to the FPGA chip, giving full play to the parallel computing capabilities of the FPGA, T1=(F-60000) / 30000*50, F: output frequency of the torque sensor 5; where T1 is the measured torque;

[0035] Taking the onboard frequency of Crio-9041 FPGA 40MHz as the acquisition period t, that is, 25ns, the feedback node is used in Labview FPGA to calculate the periodic frequency n between the two high levels of the torque flange, then e*109 / (t*n) is the torque frequency of the torque flange. The actual measurement of n at 0N·m, that is, 60khz frequency, fluctuates between 666 and 667, that is, the time difference between the two high levels at 0N·m is between 16.65ms-16.675ms, and the frequency fluctuates between 59.97hz-60.06hz. Its frequency error is only between -0.05% and 0.1%, which has higher data accuracy in small torque measurement. The sampling frequency of the previous module is 1MHz and the period is 1ms. Compared with this, the sampling rate has increased by 40 times. Under the condition that the data processing accuracy is not distorted, the calculation accuracy has increased by 40 times, especially for the small torque segment, the distortion or error of the data accuracy will lead to a large change in the result;

[0036] S3, installation of motor 3 under test:

[0037] An L-shaped bracket 4 is provided on one side of the small torque dynamometer 1, and the motor 3 to be tested is fixed on the L-shaped bracket 4. A spline flange is provided on the end of the output shaft of the small torque dynamometer 1, and then the motor shaft of the motor 3 to be tested is connected to the spline flange;

[0038] S4, no-load test:

[0039] The target speeds are input in sequence, and the corresponding no-load loss torque T2 and the corresponding motor speed N at different speeds are measured by the torque sensor 5;

[0040] S5, data acquisition system 6 connection:

[0041] Connect the motor 3 to the voltage acquisition line and current sensor of the data acquisition system 6; the data acquisition system 6 is used to collect the data required for the test: voltage, current and power;

[0042] S6, battery simulator 7 connection:

[0043] The motor 3 under test is connected to the controller through a three-phase high-voltage line. The controller controls the torque of the motor 3 under test. The battery simulator 7 is connected to the controller at one end of the motor 3 under test through a high-voltage wire harness to realize power supply. The controller and the RT real-time system 2 are connected by a low-voltage line to realize control output.

[0044] S7, data test:

[0045] The RT real-time system 2 adjusts the small torque dynamometer 1 to the required speed point through the frequency converter 10, and then loads the small torques of the motor 3 under test in sequence. The small torques are 2Nm, 4Nm, 6Nm, 8Nm, 10Nm, 12Nm, 14Nm, 16Nm, 18Nm and 20Nm respectively, and N and T1 and the controller power P1 are tested in sequence;

[0046] S8. Data processing:

[0047] In the electric state, the controller gives the tested motor 3 the power: T=T1-T2, P=N*(T1-T2) / 9550, η=N*(T1-T2) / 9550 / P1*100; in the generating state, the tested motor 3 gives the controller the power: η=P1 / P*100; where T is the motor torque, P is the motor power, and η is the motor efficiency.

[0048] It also includes a water cooling system 8 and a host computer 9. The water cooling system 8 is used to provide cooling for the motor 3 under test. The host computer 9 is connected to the RT real-time system 2 and the data acquisition system 6 respectively.

[0049] As an explanation of the small torque dynamometer 1, the small torque dynamometer 1 adopts a high-dynamic AC synchronous motor with a wider constant torque area and constant power area as a power absorption and back-drag unit, combined with a high-speed acquisition unit to achieve the measurement of the motor's small torque output on the basis of ensuring a higher torque accuracy of the system; the rated torque of the small torque dynamometer 1 is 50Nm and the rated power is 50KW.

[0050] As an illustration of the torque sensor 5, the range of the torque sensor 5 is 50 Nm. The torque sensor 4 is used to measure the torque value output by the motor in real time. It has the characteristics of high precision and high sensitivity and can accurately capture small torque changes. The model of the torque sensor 5 is HBM K-T40B.

[0051] The RT real-time system 2 controls and collects data for the entire system in real time, with an FPGA high-speed acquisition control unit and a clock frequency of 40 MHz, thereby ensuring that the reading of the torque sensor 5 still has a high degree of accuracy at the entire system level, ensuring the basic conditions for the small torque test of the motor 3 under test.

[0052] The present invention adopts a small torque dynamometer 1 to directly connect with the motor 3 to be measured, reducing the intermediate transmission of the axle box, reducing the power and torque of the dynamometer, reducing inertia, reducing the shaft loss of measuring torque, and reducing the range of the torque sensor 5 to 50Nm, thereby increasing the measurement accuracy.

[0053] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0054] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0055] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0056] The above is a detailed introduction to a method for testing small torque of a vehicle-mounted motor provided by the present application. This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for testing small torque of a vehicle-mounted motor, characterized in that: The test method comprises the following steps: S1. Torque sensor calibration: A torque sensor (5) is arranged on the output shaft of the small torque dynamometer (1), and information data detected by the torque sensor (5) is transmitted to the RT real-time system (2). A frequency converter (10) is arranged between the RT real-time system (2) and the small torque dynamometer (1). Calibration arms are installed on both sides of the output shaft of the small torque dynamometer (1) to ensure left-right balance and a torque display of 0. The torque value is calibrated by adding weights to the calibration arms to ensure the accuracy of subsequent torque measurements. After the calibration is completed, the calibration arms and weights are removed; S2, small torque processing: The actual torque is calculated using the computing power of the RT real-time system (2), and the actual torque is T1, where T1 = (F-60000) / 30000*50, and F is the output frequency of the torque sensor (5); S3. Installation of the motor under test (3): An L-shaped bracket (4) is provided on one side of the small torque dynamometer (1), and the motor (3) to be tested is fixed on the L-shaped bracket (4); a spline flange is provided at the end of the output shaft of the small torque dynamometer (1), and then the motor shaft of the motor (3) to be tested is connected to the spline flange; S4, no-load test: The target speeds are input in sequence, and the corresponding no-load loss torque T2 and the corresponding motor speed N at different speeds are measured respectively by a torque sensor (5); S5, data acquisition system (6) connection: The motor under test (3) is connected to the voltage acquisition line and current sensor of the data acquisition system (6); the data acquisition system (6) is used to collect the data required for the test: voltage, current and power; S6. Battery simulator (7) connection: The motor under test (3) is connected to the controller via a three-phase high-voltage line, the controller controls the torque of the motor under test (3), and the battery simulator (7) is connected to the controller at one end of the motor under test (3) via a high-voltage wire harness to realize power supply; the controller and the RT real-time system (2) are connected via a low-voltage line to realize control output; S7, data test: The RT real-time system (2) adjusts the small torque dynamometer (1) to a required speed point through the frequency converter (10), and then sequentially loads the small torques of the motor under test (3), the small torques being 2Nm, 4Nm, 6Nm, 8Nm, 10Nm, 12Nm, 14Nm, 16Nm, 18Nm and 20Nm, respectively, and sequentially tests N and T1 and the controller power P1 accordingly; S8. Data processing: In the electric state, the controller supplies the measured motor (3) with power: T = T1-T2, P = N*(T1-T2) / 9550, η = N* (T1-T2) / 9550 / P1*100; In the power generation state, the motor (3) under test supplies power to the controller: η=P1 / P*100; where T is the motor torque, P is the motor power, and η is the motor efficiency.

2. A method for testing low torque of a vehicle-mounted motor according to claim 1, characterized in that: The rated torque of the small torque dynamometer (1) is 50 Nm, and the rated power is 50 kW.

3. A method for testing small torque of a vehicle-mounted motor according to claim 1, characterized in that: The measuring range of the torque sensor (5) is 50 Nm.

4. A method for testing low torque of a vehicle-mounted motor according to claim 1, characterized in that: It also includes a water cooling system (8), and the water cooling system (8) is used to provide cooling for the motor (3) under test.

5. A method for testing low torque of a vehicle-mounted motor according to claim 1, characterized in that: It also includes a host computer (9), which is connected to the RT real-time system (2) and the data acquisition system (6) respectively.

6. A method for testing low torque of a vehicle-mounted motor according to claim 1, characterized in that: The output frequency of the torque sensor (5) is 30 khz-90 khz.

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