Motor operation state real-time monitoring method and monitoring system thereof

Abstract

The invention relates to a motor running state real-time monitoring method and a monitoring system thereof, the monitoring system comprises a motor sampling module, a calculation and analysis module and a display module which are connected in sequence, and the monitoring method comprises the following steps: collecting real-time voltage and real-time current data of a motor through the motor sampling module; the data are transmitted to a calculation and analysis module through a communication cable, the calculation and analysis module carries out coordinate transformation and rotation transformation based on a vector control algorithm of the motor, and real-time rotating speed, real-time torque and real-time magnetic flux data of the motor are obtained through analysis; torsional vibration data and torque pulsation data of the motor are further analyzed and obtained through band-pass filtering and low-pass filtering processing and are finally transmitted to the display module through a communication cable to be displayed in real time, and corresponding data are stored. According to the invention, effective monitoring of torsional vibration, torque pulsation and other parameters of the motor is realized, additional installation of a mechanical sensor is not needed, and the method has the advantages of high precision, strong anti-interference capability and high real-time performance.

Description

Technical Field

[0001] The present invention relates to the field of motor monitoring technology, and in particular discloses a real-time monitoring method and a monitoring system for the motor operating status, which realizes real-time and high-precision monitoring of the motor operating status based on voltage and current sampling and a motor vector control algorithm combined with communication transmission technology. Background Art

[0002] As a power electronic device that drives the motor, the inverter can achieve energy conservation and emission reduction through its speed regulation of the motor, and also meet the speed regulation requirements of the process site. Since the motor can run at different speeds, and the inverter output voltage contains high-order harmonics caused by the switching frequency of power electronic components, which will have a certain impact on the normal operation of the motor, with the increase in the application of inverters, the load system is more likely to be damaged by the shaft torsional vibration after the variable frequency speed regulation drive. In order to effectively avoid such situations, on the one hand, the inverter itself researches and develops the active suppression function for the system torsional vibration, and on the other hand, various sensors are used to monitor the torsional vibration in real time, and take measures such as shutdown protection when it exceeds the limit value.

[0003] In the existing motor monitoring technology, the motor's operating status is often monitored in real time through the motor's built-in sensors combined with corresponding algorithms. Generally, some abnormalities or faults of the motor can be detected, such as overload, short circuit, phase loss, etc. In addition, by real-time monitoring and control of the motor's operating parameters, such as voltage, current, power, speed, etc., the motor is ensured to operate in a relatively good state. In particular, for the inverter-driven motor running at different speeds, the motor flux, output voltage, output current and load torque that do not exceed the rated motor are all conditions for the motor to be in a good state. The above monitoring data all belong to the acquisition of electrical signal. If you want to monitor the non-electrical information such as the torsional vibration amplitude and torque pulsation of the motor, it is usually necessary to install magnetoelectric sensors or gear discs on the motor to obtain the motor's speed, torque and other key parameters. However, these traditional monitoring methods have many shortcomings: on the one hand, installing sensors or gear discs will increase the mechanical complexity of the motor, which may cause mechanical wear or failure; on the other hand, these sensors have high installation location and accuracy requirements, and are easily affected by electromagnetic interference, affecting the accuracy and reliability of the measurement. In addition, traditional monitoring methods make it difficult to obtain real-time information such as the motor's torsional vibration data and torque pulsation, and cannot meet the needs of modern industry for high-precision and high-reliability monitoring of the motor's operating status. Summary of the invention

[0004] The object of the present invention is to solve the defects existing in the prior art, and to provide a method and a monitoring system for real-time monitoring of the operating state of a motor. By installing a motor sampling module near the motor side, the voltage and current of the motor are collected in real time, and the data is transmitted to the calculation and analysis module through a communication cable. Based on the vector control algorithm of the motor, methods such as coordinate transformation and rotation transformation are used to analyze the real-time speed, real-time torque and real-time flux data of the motor, and further analyze and obtain data information such as torsional vibration data and torque ripple of the motor, so as to realize efficient and high-precision real-time monitoring of the operating state of the motor.

[0005] The present invention is implemented as follows: A method and a monitoring system for real-time monitoring of the operating state of a motor, the monitoring method comprising the following steps: S1. Data input: Set the nameplate parameters of the motor to be collected through a display module with an input function module, including rated voltage, rated current, rated frequency, rated speed, etc. of the motor, S2. Data collection: Collect the real-time voltage and real-time current data of the motor through a motor sampling module provided on the line at the power input end of the motor, S3. Data transmission: Transmit the real-time voltage and real-time current data collected in step S2 to the calculation and analysis module through a communication cable, and the communication cable uses optical fiber, S4. Data analysis: The calculation and analysis module, based on the vector control algorithm of the motor, performs coordinate transformation and rotation transformation on the real-time voltage and real-time current data collected in step S2, analyzes the real-time speed, real-time torque and real-time flux data of the motor, and further analyzes and obtains the torsional vibration data and torque ripple data of the motor through band-pass filtering and low-pass filtering processing, The process of the coordinate transformation and rotation transformation is as follows: First, through a 3-2 transformation, the stationary three-phase current is converted into a stationary two-phase current in the αβ coordinate system, and then through a d-q transformation, the stationary two-phase current in the αβ coordinate system is converted into a rotating two-phase current in the dq coordinate system, respectively obtaining the torque current excitation current component and the excitation current component. The calculation and analysis module uses a flux observer to obtain the orientation angle of the motor flux in the d-q transformation.

[0006] The calculation and analysis module calculates the angular velocity ω based on the orientation angle of the motor flux r and the real-time torque T and performs low-pass filtering and band-pass filtering processing to obtain the torsional vibration data and torque ripple data of the motor, where the center frequency of the band-pass filtering is the mechanical rotation frequency of the motor, and the real-time speed ω is obtained by combining the angular velocity ω r with the number of pole pairs of the motor and the real-time torque calculation, and by subtracting the speed ω after band-pass filtering of the real-time speed ω h and the speed ω after low-pass filteringg , obtain the torsional vibration data ω of the motor t , similarly, after performing low-pass filtering and band-pass filtering on the real-time torque T of the motor, obtain the torque ripple data T of the motor t .

[0007] S5. Data display: The display module receives the processed data obtained in step S4 through a communication cable and displays the real-time speed, real-time torque, real-time magnetic flux, torsional vibration data and torque ripple data of the motor in real time, as well as the historical data curve and operation trend S6. Data storage: The display module is equipped with a memory and has the function of data storage to store various data of the motor

[0008] The monitoring system for the monitoring method includes a motor sampling module, a calculation and analysis module, and a display module connected in sequence. The motor sampling module is installed near the input end of the motor and includes a current sensor and a voltage sensor provided on the motor power input line for collecting the real-time voltage and real-time current data of the motor. The calculation and analysis module is connected to the motor sampling module through a communication cable, receives the real-time voltage and real-time current data collected by the motor sampling module, and performs analysis and processing. The display module is connected to the calculation and analysis module through a communication cable for displaying the results obtained by the analysis of the calculation and analysis module in real time and storing data. The display module also has an input function module for setting the nameplate parameters of the monitored motor

[0009] The communication cable between the display module and the calculation and analysis module uses optical fiber

[0010] The motor is driven by input power through a motor driver or directly driven by a power supply grid. The motor driver is an inverter or frequency converter, an AC motor driver

[0011] The display module is equipped with a memory, including one or more readable storage media

[0012] One set of calculation and analysis modules in the monitoring system can be respectively connected to multiple sets of motor sampling modules through communication cables. The multiple sets of motor sampling modules are respectively used to collect voltage and current samples of multiple motors

[0013] The beneficial effects of the present invention are 1. There is no need to install mechanical devices such as magnetoelectric sensors or toothed discs on the motor, avoiding mechanical wear and installation complexity 2. It can collect and analyze the operation data of the motor in real time, and display it in real time through a display device. Combined with the historical data curve, it is convenient for users to timely discover the abnormal state of the motor operation 3. It can not only obtain the basic operating parameters of the motor, but also further analyze advanced information such as torsional vibration data and torque ripple, meeting the high requirements of modern industry for motor monitoring. 4. The communication cable for transmitting data between the motor sampling module and the calculation and analysis module uses optical fiber, which can effectively avoid electromagnetic interference and further ensure the stability and reliability of data transmission. Brief Description of the Drawings

[0014] Figure 1 is a schematic structural diagram of the real-time monitoring system for the operating state of the motor described in the present invention.

[0015] Figure 2 is a schematic diagram of the operation and data transmission process for the calculation and analysis module in the present invention to obtain the real-time speed, real-time driving torque, and real-time magnetic flux of the motor.

[0016] Figure 3 is based on Figure 2 The schematic diagram of the operation process for obtaining the torsional vibration data of the motor by calculating the real-time angular velocity of the motor obtained in through low-pass filtering and band-pass filtering.

[0017] Figure 4 is based on Figure 2 The schematic diagram of the operation process for obtaining the torque ripple data of the motor by calculating the real-time driving torque of the motor obtained in through low-pass filtering and band-pass filtering.

[0018] Figure 5 is a schematic structural diagram of the connection in the second embodiment of the present invention.

[0019] In the figure: 1. First motor sampling module; 11. Current sensor; 12. Voltage sensor; 13. Second motor sampling module; 2. Calculation and analysis module; 3. Display module; 4. First motor; 41. Second motor; 5. First communication cable; 51. Second communication cable; 52. Third communication cable; 53. Fourth communication cable; 6. First motor driver; 61. Second motor driver; 7. First encoder speed measurement sampling module; 71. Second encoder speed measurement sampling module; 8. First speed measurement encoder; 81. Second speed measurement encoder. Detailed Embodiments

[0020] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0021] Embodiment 1:

[0022] AsFigure 1 As shown in the figure, the present invention relates to a real-time monitoring method for the operating state of a motor and its monitoring system. The monitoring system includes a first motor sampling module 1, a calculation and analysis module 2, and a display module 3 that are connected in sequence. The first motor sampling module 1 is installed near the input end of the first motor 4 and includes a current sensor 11 and a voltage sensor 12 provided on the power input line of the first motor 4, which are used to collect the real-time voltage and real-time current data of the first motor 4. The calculation and analysis module 2 is connected to the first motor sampling module 1 through a first communication cable 5, receives the real-time voltage and real-time current data collected by the first motor sampling module 1, and performs analysis and processing. The display module 3 is connected to the calculation and analysis module 2 by a communication cable, which is used to display the results obtained by the analysis of the calculation and analysis module 2 in real time and store the data. The display module 3 is equipped with an input function module for inputting and setting the nameplate parameters of the monitored motor. The first motor 4 is driven by a power supply through a first motor driver 6 or directly driven by a power supply grid. The first motor driver 6 can be an inverter, a frequency converter, an AC motor driver, or other types of motor drivers. The communication cable in the monitoring system uses optical fiber.

[0023] According to the attached Figure 1 ~attached Figure 3 , the real-time monitoring method for the operating state of the motor according to the present invention includes the following steps: S1. Data input: Set the nameplate parameters of the motor to be collected, such as rated voltage, rated current, rated frequency, and rated speed of the motor, through the display module with an input function module. S2. Data collection: Collect the real-time voltage and real-time current data of the first motor 4 through the first motor sampling module 1. S3. Data transmission: Transmit the collected real-time voltage and real-time current data to the calculation and analysis module 2 through the first communication cable 5. S4. Data analysis: The calculation and analysis module 2 performs coordinate transformation and rotation transformation on the collected real-time voltage and real-time current data based on the vector control algorithm of the motor, analyzes and resolves the real-time speed, real-time torque, and real-time flux data of the first motor 4, and further analyzes and obtains the torsional vibration data and torque ripple data of the motor through band-pass filtering and low-pass filtering. S5. Data display: The display module 3 displays the real-time speed, real-time torque, real-time flux, torsional vibration data, torque ripple data, historical data curve, and operation trend of the motor obtained in step S4 in real time. S6. Data storage: Store the various data of the motor through the data storage function of the display module 3.

[0024] In step S2, the three-phase currents collected by the current sensor 11 in the first motor sampling module 1 are represented by I a , I b , and I c respectively. The three-phase voltages collected by the voltage sensor 12 are represented by U a , U b , and U c respectively. Among them, the current sensor 11 can also only collect two-phase currents, and the third-phase current can be calculated by formula (1): (1).

[0025] In step S4, the calculation and analysis module 2 uses a flux observer to obtain the orientation angle of the motor flux. The flux observer calculates the orientation angle θ using formula (2): (2).

[0026] After coordinate transformation and rotation transformation of the collected real-time voltage and real-time current data in step S4, the torque current component I ds and the excitation current component I qs are obtained. The transformation process is as follows: First, through 3-2 transformation, the stationary three-phase currents I a , I b , and I c are converted into stationary two-phase currents I α , I β in the αβ coordinate system. Then, through d-q transformation, the stationary two-phase currents in the αβ coordinate system are converted into rotating two-phase currents in the dq coordinate system, that is, the torque current excitation current component I ds and the excitation current component I qs are obtained respectively.

[0027] The 3-2 transformation mentioned above is shown in formula (3): (3).

[0028] The d-q transformation mentioned above is shown in formula (4): (4).

[0029] The flux observer of the calculation and analysis module 2 calculates the angular velocity ω r using formula (5): (5).

[0030] The real-time flux value in step S4 is calculated by formula (6): (6).

[0031] The real-time torque T of the first motor 4 is obtained by calculation through formula (7): (7).

[0032] The real-time rotational speed ω is obtained by calculation through formula (8): (8), where S k is the slip compensation coefficient. When the motor is an excitation synchronous motor or a permanent magnet synchronous motor, S k = 0, and p is the number of pole pairs of the motor.

[0033] In the step S4, the calculation and analysis module of the monitoring system calculates the angular velocity ω r and the real-time torque T according to the orientation angle of the motor magnetic flux, and performs low-pass filtering and band-pass filtering to obtain the torsional vibration data and torque ripple data of the motor. The center frequency of the band-pass filtering is the mechanical rotation frequency of the motor. The real-time rotational speed ω is calculated by combining the angular velocity ω r with the number of pole pairs of the motor and the real-time torque. By subtracting the rotational speed ω h after band-pass filtering from the real-time rotational speed ω g and the rotational speed ω t after low-pass filtering, the torsional vibration data ω t of the motor is obtained. Similarly, after performing low-pass filtering and band-pass filtering on the real-time torque T of the motor, the torque ripple data T

[0034] of the motor is obtained. The transfer function H(s) of the band-pass filter is formula (9): (9), wherein, according to the three variables of the frequency point ω0 where the filter acts, the notch bandwidth parameter k1, and the notch depth parameter k2, the three coefficients a, b, and c of the filter can be determined.

[0035] The transfer function G(s) of the low-pass filter is formula (10): (10), In the formula, T d is the time constant of the low-pass filter.

[0036] Example 2:

[0037] According to the appendix Figure 5The real-time monitoring system for the operation status of an electric motor described in the present invention adopts a set of calculation and analysis modules 2 to be applied to multiple sets of motor sampling modules to respectively perform voltage and current sampling on different motors. The calculation and analysis module 2 is connected to the multiple sets of motor sampling modules through communication cables and transmits sampling data. The calculation and analysis module 2 calculates and processes the sampling data of each motor according to the parameters of different motors set by the input function module of the display module 3, and then obtains the torsional vibration data and torque pulsation of each motor.

[0038] In order to further improve the calculation accuracy, a speed encoder is provided on the motor side, and the encoder speed sampling module is connected to the calculation and analysis module 2 through a communication cable, and the calculation and analysis module 2 can directly obtain the rotation speed of the motor rotor. In this embodiment, a first speed encoder 8 is provided on one side of the first motor 4, and then the first encoder speed sampling module 7 is connected to the calculation and analysis module 2 through a fourth communication cable 53, and a second speed encoder 81 is provided on one side of the second motor 41, and then the second encoder speed sampling module 71 is connected to the calculation and analysis module 2 through a third communication cable 52, and a second motor sampling module 13 is installed on the power input line of the second motor 41, and is connected to the calculation and analysis module 2 through a second communication cable 51. The first motor 4 is driven by the input power of the first motor driver 6, and the second motor 41 is driven by the input power of the second motor driver 61. The rest is the same as in Example 1. The connection method of having two or more sets of motor sampling modules for respectively sampling voltage and current of different motors is similar.

[0039] Optionally, the communication cable between the motor sampling module and the calculation and analysis module uses optical fiber, which can effectively avoid electromagnetic interference and ensure the stability and reliability of data transmission.

[0040] Optionally, the motor operating frequency acquired by the calculation and analysis module is the fundamental frequency, and FFT calculation of the variable fundamental frequency can be performed on the voltage and current of the motor.

[0041] The calculation and analysis module may include one or more processing cores, such as a quad-core processor, an octa-core processor, etc. The processor may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), or PLA (Programmable Logic Array).

[0042] The display module can be integrated with a GPU (Graphics Processing Unit), and the GPU is responsible for rendering and drawing the content to be displayed on the display screen. The display module is equipped with a memory, which can include one or more readable storage media, which can be high-speed random access memory, as well as non-volatile memory, such as one or more disk storage devices and flash storage devices.

[0043] The above specific embodiments are only preferred embodiments of the present invention, used to explain the present invention in detail, rather than limiting the present invention. Those of ordinary skill in the art can obviously make various equivalent modifications, changes and substitutions to the specific implementation manners according to the content disclosed in the present invention. These equivalent modifications, changes and substitutions should all fall within the protection scope of the present invention. The protection scope of the present invention shall be subject to the description in the claims of this application.

Claims

1. A real-time monitoring method for the operating state of a motor, characterized in that, The described monitoring method includes the following steps: S1. Data input: Set the nameplate parameters of the motor to be collected through the display module with an input function module, including the rated voltage, rated current, rated frequency, and rated speed of the motor. S2. Data collection: Collect the real-time voltage and real-time current data of the motor through the motor sampling module provided on the line at the power input end of the motor. S3. Data transmission: Transmit the real-time voltage and real-time current data collected in step S2 to the calculation and analysis module through a communication cable. S4. Data analysis: Based on the vector control algorithm of the motor, the calculation and analysis module performs coordinate transformation and rotation transformation on the real-time voltage and real-time current data collected in step S2, analyzes and obtains the real-time speed, real-time torque, and real-time magnetic flux data of the motor, and further analyzes and obtains the torsional vibration data and torque ripple data of the motor through band-pass filtering and low-pass filtering processing. S5. Data display: The display module receives the processed data obtained in step S4 through a communication cable and displays the real-time speed, real-time torque, real-time magnetic flux, torsional vibration data, torque ripple data of the motor, as well as the historical data curve and operation trend in real time. S6. Data storage: The display module is equipped with a memory and has the function of data storage to store various data of the motor.

2. A real-time monitoring method for the operating state of a motor according to claim 1, characterized in that: The communication cable described in step S3 uses optical fiber.

3. A real-time monitoring method for the operating state of a motor according to claim 1, characterized in that: The process of performing coordinate transformation and rotation transformation on the collected real-time voltage and real-time current data in step S4 is as follows: First, through 3-2 transformation, convert the stationary three-phase current into a stationary two-phase current in the αβ coordinate system, and then through d-q transformation, convert the stationary two-phase current in the αβ coordinate system into a rotating two-phase current in the dq coordinate system to obtain the torque current excitation current component and the excitation current component respectively. The calculation and analysis module uses a flux observer to obtain the orientation angle of the motor magnetic flux in the d-q transformation.

4. A real-time monitoring method for the operating state of a motor according to claim 1 or 2, characterized in that: In the step S4, the calculation and analysis module calculates the angular velocity ω based on the orientation angle of the motor magnetic flux r and the real-time torque T, and performs low-pass filtering and band-pass filtering to obtain the torsional vibration data and torque ripple data of the motor. The center frequency of the band-pass filtering is the mechanical rotation frequency of the motor. The real-time rotational speed ω is calculated by combining the angular velocity ω r with the number of pole pairs of the motor and the real-time torque. By subtracting the rotational speed ω after band-pass filtering from the real-time rotational speed ω h and the rotational speed ω after low-pass filtering g , the torsional vibration data ω of the motor is obtained t . Similarly, after performing low-pass filtering and band-pass filtering on the real-time torque T of the motor, the torque ripple data T of the motor is obtained t .

5. A real-time monitoring system for the operating state of a motor, which is used for the real-time monitoring method of the operating state of a motor as described in any one of claims 1 to 4, characterized in that: It includes a motor sampling module, a calculation and analysis module, and a display module connected in sequence. Among them, the motor sampling module is installed near the input end of the motor and includes a current sensor and a voltage sensor provided on the motor power input line for collecting the real-time voltage and real-time current data of the motor. The calculation and analysis module is connected to the motor sampling module through a communication cable, receives the real-time voltage and real-time current data collected by the motor sampling module, and performs analysis and processing. The display module is connected to the calculation and analysis module through a communication cable, is used to display the results obtained by the calculation and analysis module in real time and perform data storage. The display module also has an input function module for setting the nameplate parameters of the monitored motor.

6. The real-time monitoring system for the operating state of an electric motor according to claim 5, characterized in that: The communication cable between the display module and the calculation and analysis module uses optical fiber.

7. The real-time monitoring system for the operating state of a motor according to claim 5, characterized in that: The described motor is driven by a power supply input through a motor driver or directly driven by a power supply grid.

8. A real-time monitoring system for the operating state of an electric motor according to claim 5 or 6, characterized in that: One set of the calculation and analysis module is respectively connected to multiple motor sampling modules used to collect the voltage and current samples of multiple motors through communication cables.

9. The real-time monitoring system for the operating state of an electric motor according to claim 5, wherein: The display module is equipped with a memory, including one or more readable storage media.

10. A real-time monitoring system for the operating state of an electric motor according to claim 5 or 7, characterized in that: The motor driver described above is an inverter or frequency converter, or an AC motor driver.

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