Nonlinear mechanical load intelligent simulation method and device

Abstract

The invention relates to a nonlinear mechanical load intelligent simulation method and device, and belongs to the technical field of mechanical load simulation and testing. The device comprises an accompanying test motor, a rotating speed sensor, a loading motor, a photoelectric encoder, an inverter and a control system, wherein the accompanying test motor, the rotating speed sensor, the loading motor and the inverter are connected in sequence; the control system is respectively connected with the rotating speed sensor and the inverter, and is also connected with the loading motor through the photoelectric encoder. The simulation method comprises the following steps: selecting a proper speed step length for sampling according to the characteristics of a test target load curve, and obtaining rotating speed-current data; processing the rotating speed-current data obtained by sampling to obtain a mathematical relationship between the rotating speed of the test target and the output current of the inverter; the current output of the inverter is controlled through the control system according to the mathematical relationship obtained through fitting, and accurate control over the torque is achieved. According to the method, the limitation of a traditional test method is overcome, various complex load curves can be dealt with, and higher precision and reliability are provided for test.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical load simulation and testing, and relates to a method and a device capable of intelligently simulating a nonlinear mechanical load curve. Background Art

[0002] In the field of modern engineering and scientific research, accurate simulation and testing of mechanical load curves are crucial. Whether it is the research and development and testing of motors, frequency converters or magnetic couplings, it is necessary to accurately simulate various mechanical load conditions. However, traditional testing methods have many limitations in simulating complex load and speed relationships. They are usually limited to specific types of loads and lack flexibility and accuracy. Especially when faced with square torque, cubic torque and various nonlinear load curves with sudden increases and decreases, it is difficult to meet actual needs. For example, when conducting a square torque load test on a frequency converter or a speed regulation test on a magnetic coupling, it is difficult for existing methods to accurately reproduce complex load curves. This limitation not only affects the accuracy of the test results, but also limits the progress and innovation of product research and development. Overall, the existing load simulation methods still have the following shortcomings:

[0003] 1) Difficulty in simulating complex load curves: Traditional load simulation systems are often limited to specific types of load curves, and it is difficult to accurately simulate square torque, cubic torque, and other nonlinear load curves with sudden increases and decreases. This limitation affects the accuracy and credibility of the experimental results.

[0004] 2) Insufficient flexibility: Existing test methods lack flexibility and are difficult to adjust according to different test requirements, and cannot meet the requirements of various engineering and scientific fields for different mechanical load conditions. This limits the scope of application of R&D personnel in new product development and performance testing.

[0005] 3) Low accuracy and reliability: Due to the inability to accurately simulate complex load curves, traditional methods are insufficient in test accuracy and reliability, which in turn affects the effectiveness of product performance evaluation and improvement.

[0006] In order to overcome the above problems, there is an urgent need for a new intelligent loading method that can flexibly simulate any mechanical load curve to improve the accuracy and reliability of the test. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide an intelligent simulation method and device for nonlinear mechanical loads, which overcomes the limitations of traditional testing methods and can flexibly respond to various complex load curves, providing higher accuracy and reliability for engineering research and development and testing.

[0008] To achieve the above object, the present invention provides a nonlinear mechanical load intelligent simulation method, which includes:

[0009] S1. According to the characteristics of the test target load curve, select an appropriate speed step for sampling to obtain speed-current data;

[0010] S2, processing the sampled speed-current data to obtain a mathematical relationship between the test target speed and the inverter output current;

[0011] S3. The control system controls the current output of the inverter according to the fitted mathematical relationship to achieve precise control of the torque.

[0012] Furthermore, step S1 is specifically as follows: according to the characteristics of the test target load curve, an appropriate speed step is selected for sampling, and at each speed sampling point, the output power of the inverter is adjusted so that the shaft torque reaches the test target torque value, at which time the output current of the inverter is recorded, and then this operation is repeated until data collection of all sampling points is completed.

[0013] Furthermore, in step S2, the speed-current data obtained by sampling can be processed by high-order curve fitting to obtain the mathematical relationship. The mathematical relationship can be expressed as: I = f(n), where I represents the inverter output current, n represents the test target speed, and f(·) represents the function obtained by fitting.

[0014] Furthermore, step S3 is specifically to input the fitted mathematical formula into the control system, the control system obtains the real-time rotation speed of the test target, and substitutes it into the mathematical formula to calculate the output current of the inverter, and the control system adjusts the output current of the inverter according to the calculation result.

[0015] On the other hand, the present invention proposes a nonlinear mechanical load intelligent simulation device, which includes a test motor, a torque speed sensor, a loading motor, a photoelectric encoder, an inverter and a control system. The test motor, the torque speed sensor, the loading motor and the inverter are connected in sequence; the control system is connected to the torque speed sensor and the inverter respectively, and the control is also connected to the loading motor through the photoelectric encoder, the photoelectric encoder is used to collect the speed of the loading motor, and the input control system is used to realize the closed-loop control of the inverter.

[0016] Furthermore, a capacitor is provided between the accompanying test motor and the torque and speed sensor, and a capacitor is provided between the torque and speed sensor and the loading motor.

[0017] Furthermore, a switch and a filter unit are provided between the loading motor and the inverter, and the loading motor, the switch, the filter unit and the inverter are connected in sequence.

[0018] The beneficial effects of the present invention are:

[0019] (1) Through high-order curve fitting and real-time control, the present invention can accurately simulate various complex nonlinear mechanical load curves, including square torque, cubic torque and other sudden increase and decrease load curves, and can accurately reproduce the target curve, significantly improving the test accuracy.

[0020] (2) The present invention is not limited to a specific type of load and can be flexibly adjusted according to different test requirements. It is suitable for testing scenarios of various products such as motors, inverters, and magnetic couplers, thus broadening the application scope of the load simulation system.

[0021] (3) The present invention combines the speed signal collected by the torque sensor for calculation and adjustment, which can control the inverter output current in real time, achieve precise control of the torque, and can stably and reliably simulate the nonlinear load curve, thereby ensuring the consistency and credibility of the test results.

[0022] (4) The present invention provides an efficient intelligent loading method, simplifies the simulation process of complex load curves, and provides a precise testing environment for R&D personnel by accurately controlling load conditions, thereby accelerating the development of new products and performance optimization. At the same time, the present invention is not only suitable for laboratory environments, but can also be widely promoted in practical engineering applications. For example, in the development process of motors and inverters, the present invention can provide reliable load test data to help engineers better understand and optimize product performance.

[0023] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 The schematic diagram is a principle diagram of testing a frequency converter using the present invention;

[0026] Figure 2 It is a schematic diagram of the principle of testing a magnetic coupling device using the present invention;

[0027] Figure 3 is the target load curve;

[0028] Figure 4 It is a schematic diagram of the speed sampling points;

[0029] Figure 5 It is a schematic diagram of high-order curve fitting;

[0030] Figure 6 A schematic diagram of the process of simulating nonlinear mechanical load curves;

[0031] Figure 7 This is a schematic diagram of torque and speed curves for a square torque load test;

[0032] Figure 8 Test torque and speed curves for fast speed regulation. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0035] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0036] The present invention proposes an innovative intelligent simulation method for nonlinear mechanical loads, which can flexibly cope with complex load curves such as square torque and cubic torque, and realize accurate simulation of nonlinear mechanical loads. The method is as follows:

[0037] 1. Select the speed step for sampling

[0038] 1) According to Figure 3The characteristics of the target load curve shown in Figure 2 are used to select an appropriate speed step size for sampling, such as Figure 4 As shown, sampling is performed with a step length of 100 r / min;

[0039] 2) At each speed sampling point, the output power of the INV1 inverter is adjusted to make the shaft torque reach the target torque value;

[0040] 3) Record the inverter output current at this time, repeat the above steps until all speed sampling points are recorded, and obtain complete speed-inverter current data through the above method.

[0041] 2. High-order curve fitting

[0042] 1) Perform high-order curve fitting based on the sampled speed and inverter current corresponding data points;

[0043] 2) The mathematical relationship between the speed and the inverter output current is obtained by fitting, such as Figure 5 shown.

[0044] The mathematical relationship can be expressed as I=f(n), where I represents the inverter output current, n represents the rotation speed, and f represents the function obtained by fitting.

[0045] 3. Control system input and real-time control

[0046] The fitted mathematical formula is input into the control system, and the PLC (Programmable Logic Controller) is used to control the INV1 inverter. During operation, the PLC uses the real-time speed signal collected by the torque sensor and puts it into the mathematical formula to calculate the current required inverter output current. The control system then adjusts the inverter output current based on the calculation results to achieve precise control of the torque. The specific steps are as follows: Figure 6 As shown, the simulation of the nonlinear mechanical load curve is completed through real-time calculation and control.

[0047] 4. Testing and Verification

[0048] During the prototype testing phase, the nonlinear load curve is loaded using the above method, and the curve of torque changing with speed is recorded. Figure 7 , Figure 8 As shown, the test curve verifies the effectiveness of the method of the present invention in practical applications.

[0049] In one embodiment of the present invention, a load simulation test is performed on a frequency converter using the method proposed by the present invention. Figure 1As shown, the test device includes a test motor, a torque and speed sensor, a loading motor, a photoelectric encoder, a filter unit, an inverter and a measurement control system. The tested inverter is connected to the test motor through a switch QF2 and can drive the test motor. The loading motor is used to align the shaft with the test motor so that the current of the tested inverter is loaded to the rated current. A torque and speed sensor is set between the loading motor and the test motor to collect the torque and speed of the tested inverter in real time. The test steps of this embodiment are as follows:

[0050] 1) Turn on the tested inverter and run it at a lower speed, such as 100r / min;

[0051] 2) Set the INV1 inverter to vector mode, set the output voltage to 0, and set the target speed to 100r / min;

[0052] 3) Start the INV1 inverter and close the switch QF1 after the speed of the inverter and the tested inverter are synchronized;

[0053] 4) Increase the output voltage of the INV1 inverter to the rated voltage;

[0054] 5) Automatic control is performed through PLC. Specifically, the speed of the tested inverter is collected and input into the control system. The control system calculates the current that the INV1 inverter needs to output according to the speed-current relationship fitted in advance, thereby adjusting the output current limit of the INV1 inverter in real time.

[0055] In another embodiment of the present invention, a load simulation test is performed on a magnetic coupling using the method proposed by the present invention. Figure 2 As shown, the test device includes a test motor, a torque speed sensor, a loading motor, a photoelectric encoder, a filter unit, an inverter and a measurement control system. The magnetic coupler is arranged between the test motor and the speed sensor, and is connected to the test motor and the torque speed sensor through capacitors respectively. The test steps of this embodiment are as follows:

[0056] 1) Place the magnetic coupler under test into the test device and start the test motor;

[0057] 2) Set the INV1 inverter to vector mode, set the output voltage to 0, and set the target speed to 100r / min;

[0058] 3) Start the INV1 inverter and close the switch QF1 after the inverter and the magnetic coupler under test are synchronized;

[0059] 4) Increase the output voltage of the INV1 inverter to the rated voltage;

[0060] 5) Automatic control is performed through PLC. Specifically, the rotation speed of the magnetic coupler is collected and input into the control system. The control system calculates the current that the INV1 inverter needs to output according to the speed-current relationship fitted in advance, thereby adjusting the output current limit of the INV1 inverter in real time.

[0061] The intelligent simulation method of nonlinear mechanical loads proposed in the present invention can not only flexibly simulate complex load curves such as square torque and cubic torque, but also cope with various nonlinear load conditions of sudden increase or decrease, providing higher accuracy and reliability for the research and development and testing of products such as motors, frequency converters, and magnetic couplers. By controlling the inverter output in real time through PLC and combining high-order curve fitting technology, intelligent simulation of nonlinear mechanical loads is realized.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A nonlinear mechanical load intelligent simulation method, characterized by: The method includes: S1. According to the characteristics of the test target load curve, select an appropriate speed step for sampling to obtain speed-current data; S2, processing the sampled speed-current data to obtain a mathematical relationship between the test target speed and the inverter output current; S3. The control system controls the current output of the inverter according to the fitted mathematical relationship to achieve precise control of the torque.

2. The intelligent simulation method for nonlinear mechanical load according to claim 1, characterized in that: Step S1 is specifically as follows: according to the characteristics of the test target load curve, an appropriate speed step is selected for sampling; at each speed sampling point, the output power of the inverter is adjusted so that the shaft torque reaches the test target torque value; at this time, the output current of the inverter is recorded; and then this operation is repeated until data collection of all sampling points is completed.

3. The intelligent simulation method for nonlinear mechanical load according to claim 1, characterized in that: In step S2, the mathematical relationship is obtained by processing the sampled speed-current data through high-order curve fitting.

4. The intelligent simulation method for nonlinear mechanical load according to claim 3 is characterized in that: The mathematical relationship is expressed as: I=f(n), wherein I represents the inverter output current, n represents the test target speed, and f(·) represents the function obtained by fitting.

5. The intelligent simulation method for nonlinear mechanical load according to claim 1, characterized in that: Step S3 specifically includes inputting the fitted mathematical formula into the control system, the control system obtaining the real-time rotation speed of the test target, and substituting it into the mathematical formula to calculate the output current of the inverter, and the control system adjusting the output current of the inverter according to the calculation result.

6. An intelligent simulation device for nonlinear mechanical loads used in the method according to any one of claims 1 to 6, characterized in that: The device comprises a test motor, a torque speed sensor, a loading motor, a photoelectric encoder, an inverter and a control system; the test motor, the torque speed sensor, the loading motor and the inverter are connected in sequence; the control system is respectively connected to the torque speed sensor and the inverter, and is also connected to the loading motor through the photoelectric encoder.

7. The nonlinear mechanical load intelligent simulation device according to claim 6, characterized in that: A capacitor is arranged between the accompanying test motor and the torque and speed sensor, and a capacitor is arranged between the torque and speed sensor and the loading motor.

8. The nonlinear mechanical load intelligent simulation device according to claim 6, characterized in that: A switch and a filter unit are provided between the loading motor and the inverter, and the loading motor, the switch, the filter unit and the inverter are connected in sequence.

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