Variable frequency motor load test device and test method

Abstract

The invention discloses a variable frequency motor load testing device and method, and relates to the technical field of variable frequency motor testing, and the device comprises a motor testing installation platform, a fastening T-shaped bolt, two variable frequency speed regulation asynchronous motors of the same model, a drum-shaped coupler, two inverters, a rectifier, a three-phase voltage regulator, a frequency converter and an intermediate DC link. According to the invention, two frequency conversion speed regulation asynchronous motors of the same model are coaxially connected, and the power generation electric energy of the accompanying test motor is fed back to an intermediate direct current link through an inverter, so that the cyclic utilization of the electric energy and the dual-motor structural design are realized, complex load equipment does not need to be configured, and the fixed asset investment is reduced; for motors of different models, only corresponding accompanying test motors need to be replaced, the universality is improved, through voltage and current monitoring in an intermediate direct current link and motor rotating speed and torque parameter collection, and by combining a multi-dimensional performance evaluation model, precise evaluation of the motor load performance is achieved, the test efficiency is improved, and the strict test requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of variable frequency motor testing, and in particular to a variable frequency motor load testing device and a testing method. Background Art

[0002] A variable frequency motor refers to a motor that can adjust its speed by changing the power supply frequency and voltage. Its core advantage is that it can accurately control the output speed and torque according to actual working conditions. It is widely used in industrial fields, especially in oil and gas extraction and other scenarios with strict requirements on power equipment. It changes the power supply frequency through the inverter to achieve stepless speed regulation of the motor. Compared with traditional motors, it has higher operating efficiency and more flexible control methods.

[0003] In actual operation, variable-frequency motors need to work stably under different load conditions, and load performance directly affects their working efficiency, reliability and service life. Load testing can comprehensively evaluate the operating status of the motor under various working conditions, such as temperature rise during long-term operation under high load, torque output stability, energy efficiency ratio and other key parameters, to ensure that it can meet the performance requirements of specific scenarios in actual applications. Especially in special environments such as oil and gas extraction, once the motor has performance problems, it may lead to reduced production efficiency or even safety accidents. Therefore, load testing is an important part of ensuring the reliable operation of variable-frequency motors.

[0004] Existing variable frequency motor load tests mostly use methods such as resistor loading or generator feedback, but the existing technology still has certain defects when performing load testing on variable frequency motors. The existing technology has problems such as high energy consumption and large equipment investment. The resistor loading method converts electrical energy into heat energy and wastes it, and the traditional generator feedback system has a complex structure and requires a large number of additional load devices, which increases fixed asset investment. In addition, different models of variable frequency motors often require matching specific load devices, which have poor versatility and further increase the testing cost. In addition, the existing technology is difficult to accurately simulate actual working conditions, the testing efficiency is low, and it cannot meet the stringent testing requirements of high performance and high reliability. Therefore, it is of great significance to develop a variable frequency motor load testing device and testing method. Summary of the Invention

[0005] The purpose of the present invention is to make up for the shortcomings of the existing technology and provide a variable frequency motor load testing device and testing method. It can adopt two variable frequency speed regulation asynchronous motors of the same model, one as the tested motor and the other as the accompanying test motor, without the need for additional configuration of a large number of complex load equipment, thereby reducing the investment in fixed assets. The electric energy generated by the accompanying test motor is fed back to the intermediate DC link through the inverter to realize the recycling of electric energy. The same model motor is adopted as the accompanying test load. For motors of different models, only the corresponding accompanying test motor needs to be replaced, thereby improving the versatility of the device.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a variable frequency motor load test device, which includes: a motor test installation platform, a fastening T-bolt, two variable frequency speed regulation asynchronous motors of the same model, a drum coupling, two inverters, a rectifier, a three-phase voltage regulator, a frequency converter and an intermediate DC link, two variable frequency speed regulation asynchronous motors of the same model, namely a tested variable frequency speed regulation asynchronous motor and a companion variable frequency speed regulation asynchronous motor, and two inverters, namely inverter A and inverter B; The motor test installation platform is used to install the motor, and the fastening T-bolts are used to fix the motor on the motor test installation platform; The drum coupling is used to coaxially connect the tested variable frequency speed regulation asynchronous motor and the accompanying tested variable frequency speed regulation asynchronous motor; The three-phase voltage regulator input end is connected to the three-phase 380V power frequency power supply of the power grid, the rectifier input end is connected to the output end of the three-phase voltage regulator, and the intermediate DC link is connected to the output end of the rectifier; The output end of the A inverter is connected to the intermediate DC link, the input end of the A inverter is connected to the tested variable-frequency speed-regulating asynchronous motor through a cable, the output end of the B inverter is connected to the intermediate DC link, the input end of the frequency converter is connected to the output end of the B inverter, and its output end is connected to the tested variable-frequency speed-regulating asynchronous motor through a cable.

[0007] Furthermore, the intermediate DC link includes: a filter capacitor, a voltage sensor, a current sensor and a controller. The filter capacitor is used to filter out ripples in the DC voltage. The voltage sensor is arranged at both ends of the filter capacitor and is used to monitor the voltage value of the intermediate DC link in real time. The current sensor is connected in series in the DC circuit of the intermediate DC link and is used to monitor the current value of the intermediate DC link in real time. The output ends of the voltage sensor and the current sensor are both connected to the controller, and the controller dynamically adjusts the operating parameters of the A inverter and the B inverter according to the voltage value and the current value.

[0008] Furthermore, the drum coupling includes two half couplings, and the two half couplings are respectively connected to the output shafts of the tested variable-frequency speed-regulating asynchronous motor and the accompanying variable-frequency speed-regulating asynchronous motor.

[0009] A variable frequency motor load testing method is applicable to the variable frequency motor load testing device described above, and the method comprises the following steps: Connect the tested variable frequency speed regulating asynchronous motor and the companion variable frequency speed regulating asynchronous motor coaxially through a drum coupling, and then fix them on the motor test installation platform with fastening T-bolts; Start the three-phase voltage regulator to adjust the three-phase 380V power frequency power provided by the power grid to three-phase 600V power frequency power and supply it to the rectifier; The rectifier converts the three-phase 600V industrial frequency power into DC, establishing an 810V intermediate DC link; Control inverter B to make it output three-phase AC power with adjustable voltage and frequency, and supply it to the tested variable frequency speed regulation asynchronous motor through the frequency converter to drive the tested variable frequency speed regulation asynchronous motor to run; The tested variable-frequency speed-regulating asynchronous motor drives the coaxially connected companion variable-frequency speed-regulating asynchronous motor to generate electricity; The electric energy generated by the test variable frequency speed regulation asynchronous motor is converted into DC power by inverter A and fed back to the intermediate DC link; Monitor the voltage and current of the intermediate DC link and the speed and torque parameters of the tested variable frequency speed regulation asynchronous motor and the accompanying variable frequency speed regulation asynchronous motor; The load performance of the tested variable frequency speed regulation asynchronous motor is evaluated based on the monitoring data.

[0010] Furthermore, during the installation process of the tested variable-speed-regulating asynchronous motor and the accompanying tested variable-speed-regulating asynchronous motor, a laser alignment instrument is used to detect the coaxiality of the tested variable-speed-regulating asynchronous motor and the accompanying tested variable-speed-regulating asynchronous motor, and adjustable shims are set under the bases of the tested variable-speed-regulating asynchronous motor and the accompanying tested variable-speed-regulating asynchronous motor. By adjusting the height of the adjustable shims, the coaxiality deviation of the tested variable-speed-regulating asynchronous motor and the accompanying tested variable-speed-regulating asynchronous motor is reduced.

[0011] Furthermore, the intermediate DC link includes a filter capacitor. After the rectifier rectifies the three-phase 600V power frequency power into DC, the DC voltage is stabilized by the filter capacitor, and the capacitance C of the filter capacitor is dynamically adjusted according to the following formula: ,in, is the average current value of the intermediate DC link, is the working cycle of the tested variable frequency speed regulation asynchronous motor, is the allowable voltage fluctuation range.

[0012] Furthermore, the voltage frequency of the three-phase AC power output by the B inverter is adjusted according to the test requirements of the tested variable-frequency speed-regulating asynchronous motor, and the adjustment process adopts an adaptive fuzzy PID control algorithm. The control parameters of the algorithm are updated in real time according to the following formula: ,in, 、 、 are the initial PID parameters, 、 、 is a parameter increment adjusted in real time according to a fuzzy rule, wherein the fuzzy rule is based on the speed error of the variable frequency speed regulation asynchronous motor under test. and error rate of change generate.

[0013] Furthermore, the load performance of the tested variable frequency speed regulation asynchronous motor is evaluated based on the monitoring data, specifically including: Collect the input power of the tested variable frequency speed regulation asynchronous motor , output power , speed and torque ; Calculate the energy efficiency ratio of the tested variable frequency speed regulation asynchronous motor : ; Constructing a multidimensional performance evaluation model: ,in, are the rated speed, rated torque and rated power of the tested variable frequency speed regulation asynchronous motor respectively, is the power fluctuation value, 、 ,γ, is the weight coefficient, and , the weight coefficient is dynamically adjusted according to the following adaptive algorithm: 、 、 、 ; Output values ​​of the model based on multidimensional performance evaluation , determine the load performance level of the tested variable frequency speed regulation asynchronous motor.

[0014] Compared with the existing technology, the variable frequency motor load test device and test method have the following beneficial effects: The present invention adopts two variable-frequency speed-regulating asynchronous motors of the same model to be coaxially connected, uses a drum coupling to achieve axis overlap, constructs an electric energy circulation feedback system, and feeds back the electric energy generated by the companion test motor to the intermediate DC link through the inverter, thereby realizing the recycling of electric energy and avoiding the energy waste of traditional resistance loading. Through the dual-motor structure design, there is no need for additional configuration of complex load equipment, reducing fixed asset investment, using the same model motor as the companion test load, for motors of different models, only the corresponding companion test motor needs to be replaced, thereby improving the versatility of the device, through the intermediate DC link voltage and current monitoring and motor speed and torque parameter collection, combined with a multi-dimensional performance evaluation model, accurate evaluation of motor load performance is achieved, thereby improving test efficiency and meeting strict test requirements.

[0015] Other advantages, objects and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be learned from the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0017] Figure 1 It is a structural diagram of a variable frequency motor load test device; Figure 2 The figure is a flow chart of a variable frequency motor load testing method.

[0018] In the figure: 1. Motor test installation platform; 2. Tightening T-bolts; 3. Tested variable-speed asynchronous motor; 4. Drum coupling; 5. Companion test variable-speed asynchronous motor; 6. Inverter A; 7. Rectifier; 8. Three-phase voltage regulator; 9. Inverter B; 10. Frequency converter; 11. Intermediate DC link. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] See also Figure 1 , the variable frequency motor load test device mainly consists of the following parts: Motor test installation platform 1: Its function is to provide a basic support platform for the installation of the motor.

[0021] Tighten the T-bolts 2 to securely secure the motor to the motor test mounting platform 1 to prevent displacement during testing.

[0022] Two variable-speed asynchronous motors of the same model: the tested variable-speed asynchronous motor 3 and the accompanying variable-speed asynchronous motor 5. The tested variable-speed asynchronous motor 3 is the motor to be tested, and the accompanying variable-speed asynchronous motor 5 works as an accompanying test load to cooperate with the tested motor.

[0023] Drum coupling 4: It consists of two half-couplings, which are respectively connected to the output shafts of the tested variable-frequency speed-regulating asynchronous motor 3 and the companion variable-frequency speed-regulating asynchronous motor 5, thereby realizing the coaxial connection of the two motors and ensuring the effective transmission of power.

[0024] Two inverters: A inverter 6 and B inverter 9. The input end of A inverter 6 is connected to the test variable-frequency speed-regulating asynchronous motor 5 through a cable, and the output end is connected to the intermediate DC link 11, which is used to convert the electric energy generated by the test motor into DC power and feed it back to the intermediate DC link 11; the output end of B inverter 9 is connected to the input end of the frequency converter 10, and its output voltage and frequency adjustable three-phase AC power is supplied to the tested variable-frequency speed-regulating asynchronous motor 3 through the frequency converter 10.

[0025] The rectifier 7 has an input end connected to the output end of the three-phase voltage regulator 8 , and can rectify the three-phase power frequency power adjusted by the three-phase voltage regulator 8 into direct current, providing a direct current power supply for the intermediate direct current link 11 .

[0026] Three-phase voltage regulator 8: The input end is connected to the three-phase 380V power frequency power of the power grid, and the output end is connected to the input end of the rectifier 7, which is used to adjust the three-phase 380V power frequency power provided by the power grid to three-phase 600V power frequency power and supply it to the rectifier 7.

[0027] Frequency converter 10: The input end is connected to the output end of inverter B 9, and the output end is connected to the tested variable frequency speed regulation asynchronous motor 3 through a cable. The three-phase AC power output by inverter B 9 is further processed and then supplied to the tested motor.

[0028] The intermediate DC link 11 includes a filter capacitor, a voltage sensor, a current sensor, and a controller. The filter capacitor is used to filter out ripple in the DC voltage and stabilize the DC voltage. The voltage sensor is set at both ends of the filter capacitor and can monitor the voltage value of the intermediate DC link 11 in real time. The current sensor is connected in series in the DC circuit of the intermediate DC link 11 and is used to monitor the current value of the intermediate DC link 11 in real time. The output ends of the voltage sensor and the current sensor are both connected to the controller, which dynamically adjusts the operating parameters of the A inverter 6 and the B inverter 9 according to the monitored voltage and current values.

[0029] Example 1 This embodiment is applied to the load performance test scenario of a certain type of variable-frequency speed-regulating asynchronous motor. This motor will be used in the oil and gas extraction field, which has strict requirements on power equipment. In actual operation, the variable-frequency motor needs to work stably under different load conditions. Its load performance directly affects the working efficiency, reliability and service life. Therefore, it is necessary to comprehensively evaluate the operating status of the motor under various working conditions through load testing to ensure that it can meet the performance requirements of specific scenarios in actual applications.

[0030] See also Figure 2 The specific implementation process is as follows: First, the test device is installed and debugged, and the tested variable-frequency speed regulation asynchronous motor 3 and the companion variable-frequency speed regulation asynchronous motor 5 of the same model are coaxially connected through a drum coupling 4. The two half couplings of the drum coupling 4 are precisely connected to the output shafts of the two motors respectively.

[0031] During the installation process, a laser alignment instrument is used to detect the coaxiality of the two motors to ensure that the axis overlap meets the requirements. If coaxiality deviation is detected, adjustable shims are set under the bases of the two motors. By fine-tuning the height of the adjustable shims, the coaxiality deviation is gradually reduced to ensure the stability and accuracy of power transmission. After completing the coaxial connection, use the tightening T-bolts 2 to firmly fix the two motors on the motor test installation platform 1 to prevent the motors from shifting during the test and affecting the test results.

[0032] Next, connect the electrical system and set parameters. Connect the input of the three-phase voltage regulator 8 to the three-phase 380V power grid, and its output to the input of the rectifier 7. Connect the intermediate DC link 11 to the output of the rectifier 7. Intermediate DC link 11 includes a filter capacitor, a voltage sensor, a current sensor, and a controller. The input of inverter A 6 is connected to the accompanying variable-frequency speed-regulating asynchronous motor 5 via a cable, and the output is connected to intermediate DC link 11. The output of inverter B 9 is connected to the input of inverter 10, and the output of inverter 10 is connected to the tested variable-frequency speed-regulating asynchronous motor 3 via a cable.

[0033] Then, start the test device and turn on the three-phase voltage regulator 8 to adjust the three-phase 380V industrial frequency power provided by the power grid to three-phase 600V industrial frequency power, and supply it to the rectifier 7. The rectifier 7 rectifies the three-phase 600V industrial frequency power into DC to establish the intermediate DC link 11. During the rectification process, the filter capacitor of the intermediate DC link 11 plays a role in filtering out the ripple in the DC voltage and stabilizing the DC voltage.

[0034] The capacitance C of the filter capacitor is calculated according to the formula Dynamic adjustment, where is the average current value of the intermediate DC link 11, is the working cycle of the tested variable frequency speed regulation asynchronous motor 3, The formula is used to ensure that the capacitance of the filter capacitor can adapt to different test conditions and guarantee the stability of the DC voltage within the allowable voltage fluctuation range.

[0035] Afterwards, the inverter B 9 is controlled to output three-phase AC power with adjustable voltage and frequency, and the power is supplied to the tested variable frequency speed regulating asynchronous motor 3 through the frequency converter 10 to drive the tested motor to run. When adjusting the voltage and frequency of the three-phase AC power output by the inverter B 9, the adaptive fuzzy PID control algorithm is used. The control parameters of the algorithm are based on the formula Real-time updates, including 、 、 are the initial PID parameters, 、 、 The parameter increment is adjusted in real time according to the fuzzy rule, which is based on the speed error of the variable frequency speed control asynchronous motor 3 and error rate of change Generate,through this algorithm, the output voltage frequency of inverter B 9 is accurately adjusted to meet the requirements of different test conditions of the tested motor.

[0036] After the tested variable-frequency speed-regulating asynchronous motor 3 starts running, it drags the coaxially connected companion variable-frequency speed-regulating asynchronous motor 5 to generate electricity. The electric energy generated by the companion variable-frequency speed-regulating asynchronous motor 5 is converted into direct current by the A inverter 6 and fed back to the intermediate DC link 11 to realize the recycling of electric energy.

[0037] During the entire test process, the voltage and current of the intermediate DC link 11 and the speed and torque parameters of the tested variable-frequency speed-regulating asynchronous motor 3 and the companion variable-frequency speed-regulating asynchronous motor 5 are monitored in real time. A voltage sensor is set at both ends of the filter capacitor to monitor the voltage value of the intermediate DC link 11 in real time; a current sensor is connected in series in the DC circuit of the intermediate DC link 11 to monitor the current value of the intermediate DC link 11 in real time; at the same time, the speed and torque parameters of the two motors are collected through corresponding sensors.

[0038] Finally, the load performance of the tested variable frequency speed regulation asynchronous motor 3 is evaluated based on the monitoring data. First, the input power of the tested variable frequency speed regulation asynchronous motor 3 is collected. , output power , speed and torque Then calculate the energy efficiency ratio of the tested variable frequency speed regulation asynchronous motor 3 , the formula is .

[0039] Then build a multidimensional performance evaluation model ,in 、 、 are the rated speed, rated torque and rated power of the tested variable frequency speed regulation asynchronous motor 3, is the power fluctuation value, is the weight coefficient, and , the weight coefficient is dynamically adjusted according to the adaptive algorithm, and the formulas are 、 、 、 , based on the output values ​​of the multidimensional performance evaluation model , determine the load performance level of the tested variable frequency speed regulation asynchronous motor 3.

[0040] In summary, through the specific implementation process of this embodiment, the load performance test of this model of variable-frequency speed-regulating asynchronous motor was successfully achieved. This embodiment adopts a dual-motor structure design in which two variable-frequency speed-regulating asynchronous motors of the same model are coaxially connected. There is no need to configure additional complex load equipment, which reduces fixed asset investment. The electric energy generated by the accompanying test motor is fed back to the intermediate DC link 11 through the inverter, realizing the recycling of electric energy and avoiding the energy waste of traditional resistance loading. The multi-dimensional performance evaluation model is combined with the adaptive adjustment of the weight coefficient to achieve an accurate evaluation of the motor load performance. This embodiment improves test efficiency, meets strict test requirements, and provides a strong guarantee for the reliable operation of this model of variable-frequency motor in the field of oil and gas extraction.

[0041] Example 2 This embodiment is applied to the load performance test scenario of another type of variable frequency speed regulation asynchronous motor. The motor is intended to be used in the drive system of an industrial automation production line. Since the industrial automation production line has high requirements on parameters such as the motor's operating stability, speed regulation accuracy and energy efficiency ratio, it is necessary to conduct a comprehensive load test to evaluate the various performance indicators of the motor under different load conditions to ensure that it can operate stably and efficiently in the production line to meet the needs of industrial automation production.

[0042] See also Figure 2 The specific implementation process is as follows: First, the test equipment is constructed and the motor is installed. A companion variable-speed-adjustable asynchronous motor 5 of the same model as the tested variable-speed-adjustable asynchronous motor 3 is selected and coaxially connected via a drum coupling 4. The two half couplings of the drum coupling 4 are tightly connected to the output shafts of the tested and companion motors, respectively.

[0043] During the connection process, a laser alignment instrument is used to perform real-time detection of the coaxiality of the two motors. If a deviation in coaxiality is detected, adjustable shims are placed under the bases of the two motors. The coaxiality is accurately calibrated by fine-tuning the height of the adjustable shims to ensure that the axes of the two motors are in the same straight line to avoid vibration or poor power transmission during the test due to coaxiality deviation. After the calibration is completed, the two motors are firmly fixed to the motor test mounting platform 1 by tightening the T-bolts 2 to ensure that the motors are in a stable position and will not move during the test.

[0044] Next, complete the connection and debugging of the electrical system. Connect the input end of the three-phase voltage regulator 8 to the three-phase 380V industrial frequency power supply of the power grid, and connect its output end to the input end of the rectifier 7. The output end of the rectifier 7 is connected to the intermediate DC link 11. The intermediate DC link 11 consists of a filter capacitor, a voltage sensor, a current sensor and a controller. The input end of the A inverter 6 is connected to the output end of the test variable-frequency speed regulation asynchronous motor 5 through a cable, and its output end is connected to the intermediate DC link 11; the output end of the B inverter 9 is connected to the input end of the frequency converter 10, and the output end of the frequency converter 10 is connected to the input end of the tested variable-frequency speed regulation asynchronous motor 3 through a cable, forming a complete electrical connection circuit.

[0045] Then, the test device is started and the intermediate DC link 11 is established. The three-phase voltage regulator 8 is turned on to adjust the three-phase 380V power frequency power input from the power grid to three-phase 600V power frequency power. The three-phase 600V power frequency power is then transmitted to the rectifier 7. The rectifier 7 rectifies the three-phase 600V power frequency power and converts it into DC power, thereby establishing the intermediate DC link 11. In the intermediate DC link 11, the filter capacitor filters the rectified DC voltage to remove the ripple component therein to stabilize the DC voltage. The capacitance C of the filter capacitor is calculated according to the formula Dynamic adjustment, where is the average current value of the intermediate DC link 11, is the working cycle of the tested variable frequency speed regulation asynchronous motor 3, To ensure the voltage fluctuation range allowed, the capacitance of the filter capacitor is adjusted in real time through this formula so that it can adapt to the current and voltage changes under different test conditions and ensure the voltage stability of the intermediate DC link 11.

[0046] After that, the B inverter 9 is controlled to output three-phase AC power with adjustable frequency. According to the test requirements of the variable frequency speed control asynchronous motor 3, the output voltage frequency of the B inverter 9 is adjusted. In the adjustment process, the adaptive fuzzy PID control algorithm is used. The control parameters of the algorithm are given by the formula Real-time updates, including 、 are the preset initial PID parameters, 、 The parameter increment is adjusted in real time according to the fuzzy rule, and the fuzzy rule is based on the rotation error of the variable frequency speed control asynchronous motor 3 and error rate of change Generated, through this algorithm, accurate control of the output voltage frequency of inverter B 9 is achieved, so that the output three-phase AC power can meet the speed and torque requirements of the tested motor in different test stages.

[0047] When the tested variable-frequency speed-regulating asynchronous motor 3 is driven by the three-phase AC power output by the B inverter 9, it drags the accompanying test variable-frequency speed-regulating asynchronous motor 5 to operate synchronously through the drum coupling 4, so that the accompanying test motor is in a power generation state. The electric energy generated by the accompanying test variable-frequency speed-regulating asynchronous motor 5 is converted into direct current through the A inverter 6, and then fed back to the intermediate DC link 11, realizing the recycling of electric energy and reducing energy loss during the test process.

[0048] During the entire test process, the voltage and current of the intermediate DC link 11 and the speed and torque parameters of the two motors are continuously monitored. The voltage sensor is installed at both ends of the filter capacitor for real-time monitoring of the voltage value of the intermediate DC link 11; the current sensor is connected in series in the DC circuit of the intermediate DC link 11 for real-time monitoring of the current value in the circuit.

[0049] At the same time, speed sensors and torque sensors are installed on the tested variable-frequency speed-regulating asynchronous motor 3 and the accompanying variable-frequency speed-regulating asynchronous motor 5 respectively to collect the speed and torque data of the two motors in real time. These monitoring data are transmitted to the controller in real time. The controller dynamically adjusts the working parameters of inverter A 6 and inverter B 9 according to the received voltage and current data to ensure the stable operation of the test device.

[0050] Finally, the load performance of the tested variable frequency speed regulation asynchronous motor 3 is evaluated based on the collected monitoring data. First, the input power of the tested motor is collected. , output power , speed and torque and other parameters, and then through the formula Calculate the energy efficiency ratio of the tested motor Then build a multidimensional performance evaluation model ,in 、 、 are the rated speed, rated torque and rated power of the tested variable frequency speed regulation asynchronous motor 3, is the power fluctuation value, the weight coefficient in the model , β, γ, δ satisfy , and dynamically adjusted through adaptive algorithms. The specific adjustment formula is: 、 、 、 , based on the output values ​​of the multidimensional performance evaluation model , determine the load performance level of the tested motor, and thus comprehensively evaluate the performance of the motor in the application scenario of industrial automation production line.

[0051] In summary, the load performance test of the variable-frequency speed-regulating asynchronous motor used in the drive system of the industrial automation production line was successfully completed. This embodiment fully utilized the proposed dual-motor coaxial connection structure, without the need to configure complex load equipment, effectively reducing the test cost and fixed asset investment. The multi-dimensional performance evaluation model combined with the adaptive weight coefficient adjustment achieved a comprehensive and accurate evaluation of the motor load performance. This embodiment not only improved the test efficiency, but also accurately evaluated the various performance indicators of the motor in the industrial automation production scenario, providing important technical support and data basis for the reliable application of the motor in the industrial automation production line, fully demonstrating the superiority and practicality of this patented technology in practical applications.

[0052] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A variable frequency motor load testing device, characterized in that: The device comprises: a motor test installation platform (1), a fastening T-bolt (2), two variable-frequency speed-regulating asynchronous motors of the same model, a drum coupling (4), two inverters, a rectifier (7), a three-phase voltage regulator (8), a frequency converter (10) and an intermediate DC link (11), two variable-frequency speed-regulating asynchronous motors of the same model, namely the tested variable-frequency speed-regulating asynchronous motor (3) and the accompanying variable-frequency speed-regulating asynchronous motor (5), and two inverters, namely inverter A (6) and inverter B (9); The motor test installation platform (1) is used to install the motor, and the fastening T-bolts (2) are used to fix the motor on the motor test installation platform (1); The drum coupling (4) is used to coaxially connect the tested variable-frequency speed-regulating asynchronous motor (3) and the accompanying tested variable-frequency speed-regulating asynchronous motor (5); The input end of the three-phase voltage regulator (8) is connected to the three-phase 380V power frequency of the power grid, the input end of the rectifier (7) is connected to the output end of the three-phase voltage regulator (8), and the intermediate DC link (11) is connected to the output end of the rectifier (7); The output end of the A inverter (6) is connected to the intermediate DC link (11), the input end of the A inverter (6) is connected to the test variable-frequency speed-regulating asynchronous motor (5) through a cable, the output end of the B inverter (9) is connected to the intermediate DC link (11), the input end of the frequency converter (10) is connected to the output end of the B inverter (9), and the output end thereof is connected to the tested variable-frequency speed-regulating asynchronous motor (3) through a cable.

2. A variable frequency motor load testing device according to claim 1, characterized in that: The intermediate DC link (11) includes: a filter capacitor, a voltage sensor, a current sensor, and a controller. The filter capacitor is used to filter out ripples in the DC voltage. The voltage sensor is arranged at both ends of the filter capacitor and is used to monitor the voltage value of the intermediate DC link (11) in real time. The current sensor is connected in series in the DC circuit of the intermediate DC link (11) and is used to monitor the current value of the intermediate DC link (11) in real time. The output ends of the voltage sensor and the current sensor are both connected to the controller. The controller dynamically adjusts the operating parameters of the A inverter (6) and the B inverter (9) according to the voltage value and the current value.

3. A variable frequency motor load testing device according to claim 1, characterized in that: The drum coupling (4) comprises two half couplings, and the two half couplings are respectively connected to the output shafts of the tested variable-frequency speed-regulating asynchronous motor (3) and the accompanying variable-frequency speed-regulating asynchronous motor (5).

4. A variable frequency motor load testing method, applicable to a variable frequency motor load testing device according to claims 1-3, characterized in that: The method comprises the following steps: After the tested variable frequency speed regulating asynchronous motor (3) and the accompanying variable frequency speed regulating asynchronous motor (5) are coaxially connected through a drum coupling (4), they are fixed on the motor test installation platform (1) with a fastening T-bolt (2); Start the three-phase voltage regulator (8) to adjust the three-phase 380V power frequency power provided by the power grid to three-phase 600V power frequency power and supply it to the rectifier (7); The rectifier (7) rectifies the three-phase 600V power frequency power into DC, establishing an 810V intermediate DC link (11); Controlling inverter B (9) to output three-phase AC power with adjustable voltage and frequency, and supplying the tested variable frequency speed regulation asynchronous motor (3) through the frequency converter (10) to drive the tested variable frequency speed regulation asynchronous motor (3) to operate; The tested variable-frequency speed-regulating asynchronous motor (3) drives the coaxially connected companion variable-frequency speed-regulating asynchronous motor (5) to generate electricity; The electric energy generated by the variable frequency speed regulating asynchronous motor (5) is converted into direct current by the A inverter (6) and fed back to the intermediate DC link (11); Monitor the voltage and current of the intermediate DC link (11) and the speed and torque parameters of the tested variable-frequency speed-regulating asynchronous motor (3) and the accompanying variable-frequency speed-regulating asynchronous motor (5); The load performance of the tested variable frequency speed regulation asynchronous motor (3) is evaluated based on the monitoring data.

5. A variable frequency motor load testing method according to claim 4, characterized in that: During the installation process of the tested variable-speed-regulating asynchronous motor (3) and the accompanying tested variable-speed-regulating asynchronous motor (5), a laser alignment instrument is used to detect the coaxiality of the tested variable-speed-regulating asynchronous motor (3) and the accompanying tested variable-speed-regulating asynchronous motor (5), and adjustable shims are provided under the bases of the tested variable-speed-regulating asynchronous motor (3) and the accompanying tested variable-speed-regulating asynchronous motor (5). By adjusting the height of the adjustable shims, the coaxiality deviation of the tested variable-speed-regulating asynchronous motor (3) and the accompanying tested variable-speed-regulating asynchronous motor (5) is reduced.

6. A variable frequency motor load testing method according to claim 4, characterized in that: The intermediate DC link (11) includes a filter capacitor. After the rectifier (7) rectifies the three-phase 600V power frequency power into DC, the DC voltage is stabilized by the filter capacitor, and the capacitance C of the filter capacitor is dynamically adjusted according to the following formula: ,in, is the average current value of the intermediate DC link (11), is the working cycle of the tested variable frequency speed regulation asynchronous motor (3), is the allowable voltage fluctuation range.

7. A variable frequency motor load testing method according to claim 4, characterized in that: The voltage frequency of the three-phase alternating current output by the B inverter (9) is adjusted according to the test requirements of the variable frequency speed regulation asynchronous motor (3) under test, and the adjustment process adopts an adaptive fuzzy PID control algorithm, and the control parameters of the algorithm are updated in real time according to the following formula: ,in, 、 、 are the initial PID parameters, 、 、 is a parameter increment adjusted in real time according to a fuzzy rule, wherein the fuzzy rule is based on the speed error of the variable frequency speed regulating asynchronous motor (3) under test. and error rate of change generate.

8. A variable frequency motor load testing method according to claim 4, characterized in that: The load performance of the tested variable frequency speed regulation asynchronous motor (3) is evaluated based on the monitoring data, specifically including: Collect the input power of the tested variable frequency speed regulation asynchronous motor (3) , output power , speed and torque ; Calculate the energy efficiency ratio of the tested variable frequency speed regulating asynchronous motor (3) : ; Constructing a multidimensional performance evaluation model: ,in, are the rated speed, rated torque and rated power of the tested variable frequency speed regulating asynchronous motor (3), is the power fluctuation value, 、 ,γ, is the weight coefficient, and ; Output values ​​of the model based on multidimensional performance evaluation , determine the load performance level of the tested variable frequency speed regulation asynchronous motor (3).

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