A system and method for dynamic measurement of magnetic flux of a permanent magnet rotor

Abstract

The application discloses a kind of permanent magnet rotor magnetic flux dynamic measurement system and method, belong to industrial automation and intelligent manufacturing technical field.The system includes measurement coil assembly, drive mechanism and magnetic flux dynamic measuring instrument;Measurement coil assembly is customized according to the shape and pole number of the permanent magnet rotor to be measured, for generating superimposed induced electromotive force when permanent magnet rotor passes;Drive mechanism is used to move permanent magnet rotor from the side of measurement coil assembly to the other side at a constant speed;Magnetic flux dynamic measuring instrument is electrically connected with measurement coil assembly, for processing induced electromotive force signal, calculating the total magnetic flux of permanent magnet rotor, and controlling the action of drive mechanism.The application improves the safety of measuring instrument, ensures the normal use of instrument, improves the measurement accuracy and speed, and reduces the manufacturing difficulty of measurement coil.

Description

Technical Field

[0001] This invention relates to the field of industrial automation and intelligent manufacturing technology, specifically to a system and method for dynamic measurement of magnetic flux of a permanent magnet rotor. Background Technology

[0002] With the deepening of global energy transition and industrial upgrading, high-efficiency drive technologies, represented by permanent magnet synchronous motors, have experienced explosive growth. Permanent magnet motors, with their high efficiency, high power density, excellent dynamic response, and control performance, have been widely used in new energy vehicle drives, industrial servo systems, wind power generation, high-end home appliances, and various precision automated equipment, becoming a key component in modern high-end equipment and energy conservation.

[0003] As the "heart" of a permanent magnet motor, the magnetic properties of the permanent magnet rotor directly determine the motor's core indicators such as output torque, efficiency, temperature rise, vibration, and noise. The uniformity, stability, and consistency of the rotor's magnetic flux (or linkage) are the cornerstones for ensuring the overall performance and reliability of the motor. Therefore, accurate and efficient magnetic property testing of the permanent magnet rotor is an indispensable quality control step in the motor manufacturing process.

[0004] The surge in the application of permanent magnet rotors has been accompanied by a relative lag in performance measurement and quality control methods during their production process, becoming a prominent bottleneck restricting the industry's high-quality development and affecting the stability of end products. The current measurement challenges prevalent in the industry are mainly reflected in the following two aspects: 1) Limitations of high-precision "magnetic measurement": Currently, for permanent magnet rotors with extremely high magnetic performance requirements or high value (such as rotors used in drive motors for new energy vehicles and high-end servo motors), manufacturers typically use magnetic flux density distribution measurement (i.e., "surface magnetic field measurement") for analysis. Its advantage is that it can accurately assess the uniformity of magnetization of the magnets, the presence of localized low magnetism, or assembly defects. However, its drawbacks are also obvious: ① System complexity: It requires precise mechanical positioning devices, high-precision sensors, and data acquisition systems, resulting in high equipment costs. ② Time-consuming process: Multiple or multi-channel scans of the rotor surface require 30-60 seconds or longer.

[0005] 2) Limitations and risks of "total flux evaluation": Faced with a massive number of relatively low-value permanent magnet rotors (such as rotors used in ordinary variable frequency household appliance motors), manufacturers generally rely on total magnetic flux measurement to assess quality for cost and efficiency reasons. While measurement using customized coils and fluxmeters is relatively quick and inexpensive, it also has significant drawbacks: ① Information is missing; only a total magnetic flux value is obtained, failing to reflect the spatial distribution of magnetic flux on the rotor surface, often leading to the omission of local defects; ② Measurement coil assemblies for different rotor specifications must be customized, making it impossible to use conventional coils such as Helmholtz coils; ③ Typical fluxmeters are static measuring instruments, requiring the rotor to be in a precise position before pull-out measurement can be initiated. Whether manual or semi-automatic pull-out measurement, efficiency remains low, making it unsuitable for assembly line applications.

[0006] To address the aforementioned issues, there is an urgent need for a system and method for dynamic measurement of permanent magnet rotor flux, which can solve the problems existing in traditional methods. Summary of the Invention

[0007] The purpose of this invention is to provide a system and method for dynamic measurement of permanent magnet rotor flux, which improves the safety of the measuring instrument, ensures the normal use of the instrument, improves the measurement accuracy and speed, and reduces the manufacturing difficulty of the measuring coil.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A system for dynamic measurement of magnetic flux of a permanent magnet rotor includes: a measuring coil assembly, a drive mechanism, and a dynamic magnetic flux measuring instrument; The measuring coil assembly is customized according to the shape and number of poles of the permanent magnet rotor being measured, and is used to generate a superimposed induced electromotive force when the permanent magnet rotor passes through it. The drive mechanism is used to move the permanent magnet rotor from one side of the measuring coil assembly to the other side at a constant speed; The magnetic flux dynamic measuring instrument is electrically connected to the measuring coil assembly, and is used to process the induced electromotive force signal, calculate the total magnetic flux of the permanent magnet rotor, and control the action of the drive mechanism.

[0009] Furthermore, the measuring coil assembly includes multiple measuring coils and a multi-pole toroidal magnetic core. The number of measuring coils is equal to the number of magnetic poles of the permanent magnet rotor being measured, and all measuring coils are connected in series end to end. The winding directions of the measuring coils corresponding to the N pole and the S pole are opposite, and all the measuring coils are fixedly mounted on the magnetic poles of the multi-pole toroidal magnetic core.

[0010] Furthermore, the multi-pole toroidal magnetic core is made of laminated silicon steel sheets or soft magnetic materials.

[0011] Furthermore, the measuring coil assembly is provided with a positioning device and a guiding device to ensure that the N pole and S pole of the permanent magnet rotor being measured are aligned with the corresponding measuring coil.

[0012] Furthermore, the magnetic flux dynamic measurement instrument includes: a coil interface, an integration unit, an AD conversion and data processing unit, a display unit, a communication interface, an I / O interface, and an MCU. The measurement coil assembly is connected to the coil interface, the coil interface is connected to the integration unit, the integration unit is connected to the AD conversion and data processing unit, the AD conversion and data processing unit is connected to the display unit, and the coil interface, integration unit, AD conversion and data processing unit, display unit, communication interface, and I / O interface are all connected to the MCU. The coil interface is used to receive analog signals acquired by the measurement coil assembly; The integral calculation unit is used to convert the induced electromotive force back into a magnetic flux analog signal; The AD conversion and data processing unit is used to convert the magnetic flux analog signal into a digital signal and perform digital filtering. The IO interface is used to sense the position or status information of the drive mechanism and output control signals to control the movement of the drive mechanism. The MCU is used to coordinate and control the operation of each part.

[0013] Furthermore, the communication interface includes an RS485 interface and an RJ45 interface, which are used to communicate with an external programmable logic controller or industrial control computer to realize remote control of the measurement process and sharing of measurement data.

[0014] The present invention also provides a method for dynamic measurement of magnetic flux in a permanent magnet rotor, applied to the aforementioned system for dynamic measurement of magnetic flux in a permanent magnet rotor, comprising: Step 1: Load and position the permanent magnet rotor to the measurement start position, and trigger the dynamic measurement program; Step 2: Initialize the magnetic flux dynamic measurement instrument; Step 3: Output control signals through the IO interface to control the drive mechanism to move the permanent magnet rotor from the measurement start position to the measurement coil assembly at a constant speed until the measurement end position; Step 4: During the movement of the permanent magnet rotor, the measuring coil assembly generates a continuously changing superimposed induced electromotive force, which is transmitted to the magnetic flux dynamic measuring instrument. Step 5: The magnetic flux dynamic measurement instrument performs integration calculations and high-speed analog-to-digital conversion on the induced electromotive force, and records the minimum and maximum values ​​of magnetic flux in real time during the measurement process; Step 6: Calculate the total magnetic flux of the permanent magnet rotor under test based on the maximum and minimum magnetic flux values, and display the measurement results or output them through the communication interface; Step 7: After the measurement is completed, unload the permanent magnet rotor and restore the drive mechanism to its initial position.

[0015] Furthermore, in step 2, the magnetic flux dynamic measurement instrument is initialized, specifically as follows: Discharge the integrating capacitor in the integrating unit of the magnetic flux dynamic measuring instrument, and reset the total magnetic flux value, maximum value, and minimum value displayed by the instrument to zero.

[0016] In summary, the present invention has at least one of the following beneficial technical effects: 1. This invention extends the extreme value measurement time window, ensuring accuracy while reducing the stringent requirements on instrument hardware.

[0017] 2. This invention selects a suitable measuring coil height, which improves the measurement accuracy and speed.

[0018] 3. The magnetic flux dynamic measurement instrument of the present invention adopts a multi-functional design, which can not only realize a minimized dynamic system at low cost, but also the open protocol can be used for measurement in various factory production lines. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system of the present invention; Figure 2 This is a schematic diagram of the measuring coil assembly structure; Figure 3 This is a schematic diagram of the structure of a magnetic flux dynamic measurement instrument; Figure 4 This is a schematic flowchart of the method of the present invention; Figure 5 A schematic diagram illustrating the motion trajectory during the measurement process is provided, using a pair of magnetic poles instead of a rotor. Figure 6a This is a schematic diagram of the changes in magnetic flux, induced electromotive force, and extreme value measurement windows under static coil conditions. Figure 6b A schematic diagram showing the measurement windows for magnetic flux, induced electromotive force, and extreme values ​​after changing coil parameters; Figure 7 Schematic diagrams of several methods for measuring the height of a coil relative to the height of a magnetic pole.

[0020] Reference numerals: 1. Measuring coil assembly; 2. Drive mechanism; 3. Magnetic flux dynamic measuring instrument; 4. Measuring coil; 5. Multi-pole toroidal magnetic core; 6. Permanent magnet rotor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] like Figure 1 As shown, the present invention provides a system for dynamic measurement of magnetic flux of a permanent magnet rotor, comprising: a measuring coil assembly 1, a driving mechanism 2, and a magnetic flux dynamic measurement instrument 3; The measuring coil assembly 1 is customized according to the shape and number of poles of the permanent magnet rotor 6 being measured, and is used to generate a superimposed induced electromotive force when the permanent magnet rotor 6 passes through it. The drive mechanism 2 is used to move the permanent magnet rotor 6 from one side of the measuring coil assembly 1 to the other side at a constant speed; The magnetic flux dynamic measuring instrument 3 is electrically connected to the measuring coil assembly 1, and is used to process the induced electromotive force signal, calculate the total magnetic flux of the permanent magnet rotor 6, and control the action of the drive mechanism 2.

[0023] The measuring coil assembly 1 needs to be customized according to the different shapes and pole numbers of the permanent magnet rotor 6. The purpose is to superimpose the induced electromotive force corresponding to the magnetic flux passing through the coil of all N poles and S poles of the permanent magnet rotor 6. The function of the drive mechanism 2 is to move the permanent magnet rotor 6 from one side of the measuring coil assembly 1 to the other side at a constant speed to complete a measurement process. In addition to processing and analyzing the continuous signal input from the measuring coil assembly 1 and calculating the total magnetic flux, the magnetic flux dynamic measuring instrument 3 also has basic input and output control capabilities, detects the position of the permanent magnet rotor 6, controls the drive mechanism 2 to drive the permanent magnet rotor 6 to reciprocate, and has an external communication intelligent interface.

[0024] The following is a detailed introduction to each part: like Figure 2 As shown, the measuring coil assembly 1 includes multiple measuring coils 4 and a multi-pole toroidal magnetic core 5, which is customized for a specific permanent magnet rotor 6 under test, specifically as follows: 1. The number of measuring coils 4 is equal to the number of poles of the rotor. All coils are connected in series end to end (with the N pole and S pole winding in opposite directions) so that the induced electromotive force of all magnetic poles corresponding to the coils is superimposed. 2. To minimize magnetic circuit losses, the measuring coil 4 is fixed on the magnetic poles of the multi-pole annular magnetic core 5, the gap between the magnetic poles and the rotor surface is kept as small as possible, and the multi-pole annular magnetic core 5 is made of laminated silicon steel sheets or soft magnetic materials. 3. The measuring coil assembly 1 is equipped with a positioning device and guide devices on the upper and lower sides to ensure that after the permanent magnet rotor 6 enters from one side of the measuring coil assembly 1, the N pole and S pole can be aligned with the corresponding measuring coil 4, thus ensuring the consistency of the results during repeated measurements.

[0025] The function of the drive mechanism 2 is to move the permanent magnet rotor 6 from the measurement start position on one side of the measuring coil assembly 1 to the measurement end position on the other side at a constant speed. Due to differences in the methods of installing and removing the permanent magnet rotor 6 in actual applications, the drive mechanism 2 and its control method will vary, such as... Figure 1 Two case studies can be derived from this, which will be introduced separately: Case 1: If the permanent magnet rotor 6 is installed at the measurement start position and removed at the measurement end position, it can be driven by a cylinder. Normally, it waits at the measurement start position. After the rotor is installed, as the dynamic measurement proceeds, the permanent magnet rotor 6 is pushed to the measurement end position. After it is removed, the drive mechanism 2 returns to the measurement start position and waits for the next measurement.

[0026] Case 2: If the installation and removal of the permanent magnet rotor 6 are both at the measurement termination position, the drive mechanism 2 will normally wait at the measurement termination position. After the rotor is installed, the drive mechanism 2 will first move to the measurement start position, and then start the measurement to move to the termination position. After removal, it will wait in the original position for the next measurement to be loaded.

[0027] like Figure 3 As shown, the magnetic flux dynamic measuring instrument 3 includes: a coil interface, an integration unit, an AD conversion and data processing unit, a display unit, a communication interface, an I / O interface, and an MCU. The measuring coil assembly 1 is connected to the coil interface, the coil interface is connected to the integration unit, the integration unit is connected to the AD conversion and data processing unit, the AD conversion and data processing unit is connected to the display unit, and the coil interface, the integration unit, the AD conversion and data processing unit, the display unit, the communication interface, and the I / O interface are all connected to the MCU. The coil interface is used to receive the analog signal collected by the measuring coil assembly 1. In addition to the design of a high voltage penetration protection circuit, it is internally equipped with a range switching electronic switch to adapt to the actual magnetic flux of the object being measured in order to achieve the best measurement accuracy. The integral operation unit is used to restore the induced electromotive force to the magnetic flux analog signal, and is composed of an integral operation amplifier circuit and an automatic drift tracking compensation circuit. The AD conversion and data processing unit is used to convert the magnetic flux analog signal into a digital signal and perform digital filtering to eliminate the interference of the measured value. Conventional static fluxmeters only need to perform AD conversion 3 to 5 times per second, while this instrument performs AD conversion 100 to 1000 times per second while ensuring 24-bit measurement accuracy during dynamic measurement. The display unit displays the minimum, maximum, and calculated measurement values ​​measured during the dynamic measurement process through the instrument's built-in display screen. The IO interface includes an input interface and an output interface, which are optocoupled and isolated from the outside world. The input interface senses the position or status information of the drive mechanism 2, and the output interface controls the movement of the drive mechanism 2. In conjunction with the drive mechanism 2, fully automatic measurement can be completed after the permanent magnet rotor 6 is loaded. The communication interface includes an RS485 interface and an RJ45 interface, which are used to communicate with an external programmable logic controller or industrial control computer to realize remote control of the measurement process and sharing of measurement data. For example, intelligent devices can configure and control the instrument's measurement and output through the communication interface. For applications that embed dynamic measurement in production lines, through communication between the production line PLC and the instrument, the PLC can take over the motion control of the permanent magnet rotor 6 in the measurement stage, realizing a perfect combination of the motion of the permanent magnet rotor 6 and the dynamic measurement of magnetic flux. The MCU is the main control chip of the instrument, used to coordinate and control the operation of each part; In addition, the instrument also includes general modules such as power supplies, which will not be specifically mentioned here.

[0028] This flux dynamic measuring instrument integrates static and dynamic measurement, and the measurement state can be switched via the configuration menu or communication interface. During static measurement, the AD conversion rate is 10 times / second; during dynamic measurement, the AD conversion rate is 250 times / second (customizable to over 1000 times / second as needed).

[0029] like Figure 4 As shown, the present invention also provides a method for dynamic measurement of permanent magnet rotor flux, applied to the above-mentioned system for dynamic measurement of permanent magnet rotor flux, comprising: Step 1: Load and position the permanent magnet rotor to the measurement start position, and trigger the dynamic measurement program; Step 2: Initialize the magnetic flux dynamic measurement instrument; Step 3: Output control signals through the IO interface to control the drive mechanism to move the permanent magnet rotor from the measurement start position to the measurement coil assembly at a constant speed until the measurement end position; Step 4: During the movement of the permanent magnet rotor, the measuring coil assembly generates a continuously changing superimposed induced electromotive force, which is transmitted to the magnetic flux dynamic measuring instrument. Step 5: The magnetic flux dynamic measurement instrument performs integration calculations and high-speed analog-to-digital conversion on the induced electromotive force, and records the minimum and maximum values ​​of magnetic flux in real time during the measurement process; Step 6: Calculate the total magnetic flux of the permanent magnet rotor under test based on the maximum and minimum magnetic flux values, and display the measurement results or output them through the communication interface; Step 7: After the measurement is completed, unload the permanent magnet rotor and restore the drive mechanism to its initial position.

[0030] In step 2, the magnetic flux dynamic measurement instrument is initialized, specifically as follows: Discharge the integrating capacitor in the integrating unit of the magnetic flux dynamic measuring instrument, and reset the total magnetic flux value, maximum value, and minimum value displayed by the instrument to zero.

[0031] Based on the above system and method, this invention provides several different application embodiments, which are described below: Example 1: Magnetic Flux Dynamic Measurement Instrument Combined with State Detection and Drive Control This is a simplified dynamic measurement system, consisting of three parts: a measuring coil assembly, a drive mechanism, and a magnetic flux dynamic measuring instrument. It is primarily designed for applications with relatively small measurement tasks. The permanent magnet rotor is manually installed and removed, and the measurement is initiated manually (the permanent magnet rotor is installed below the measuring coil and removed from above). The specific operating steps are as follows: Step 1: After the permanent magnet rotor is loaded and positioned, the manual button start signal (or automatic positioning detection signal) triggers the dynamic measurement program to run through the switch input port of the magnetic flux dynamic measurement instrument.

[0032] Step 2: First, discharge the integrating capacitor inside the instrument and reset the displayed value, maximum value, and minimum value of the measuring instrument to zero to complete the initialization before measurement. Then, the instrument outputs a control signal from the IO interface to drive the permanent magnet rotor into the measuring coil assembly.

[0033] Step 3: As the permanent magnet rotor approaches the measuring coil assembly ( Figure 5 At position ① in the diagram, a small amount of magnetic flux begins to pass through the corresponding coils of the N and S poles of the permanent magnet rotor, generating an induced electromotive force. Once the magnetic poles and the coils begin to intersect (…),… Figure 5 (Position ② in the diagram), the magnetic flux increases rapidly until the coil is almost filled with magnetic poles, or the rotor magnetic poles are almost completely inside the coil (if the magnetic pole height is lower than the measuring coil height, such as...). Figure 7 At position ① in the diagram, the magnetic flux Φ only begins to slowly increase towards its maximum value. Figure 5 (Position ③ in the diagram represents the maximum value position), during which the electromotive force induced in the coil... The magnetic flux will increase from 0 to a maximum as the rate of change of magnetic flux increases, and then fall back to 0. For details on the changes in magnetic flux Φ and electromotive force ε, see [link to documentation]. Figure 6a At time t0.

[0034] Step 4: The permanent magnet rotor continues to move, from... Figure 5 From position ③ to position ⑤, the magnetic flux decreases from its maximum value to 0. Similarly, the polarity of the electromotive force generated at the ends of the coil is opposite to that of the process from ① to ③. For details on the changes in magnetic flux Φ and electromotive force ε, please refer to [link to documentation]. Figure 6b At time t0.

[0035] Step 5: In Figure 5Throughout the entire movement from positions ① to ⑤, the magnetic flux dynamic measuring instrument converts the electromotive force generated by the measuring coil into a current signal, performs integration calculations, and then measures the magnetic flux value Φ at each moment through a high-speed, high-precision analog-to-digital converter circuit, recording the maximum value Φ at position ③. 大 (or minimum value) and the minimum value Φ at position ① or ⑤ 小 (or maximum value). The total magnetic flux Φ of the rotor being measured. 总 It can be obtained through the following formula: Φ 总 =Φ 大 -Φ 小 ; The above measurements were performed with the permanent magnet rotor outside the measuring coil at both the starting and ending positions. Figure 5 (At positions ① and ⑤ in the diagram), no magnetic flux passes through the measuring coil on the permanent magnet rotor poles. At this time, the minimum magnetic flux is at position ① or ⑤, and the value is 0 or a negative number close to 0. The maximum magnetic flux is near position ③, close to the total magnetic flux value.

[0036] In practice, structural limitations may cause the start and end positions to deviate from the above. Figure 3 In this dynamic measurement, a slight overlap between the starting position of the permanent magnet rotor and the measuring coil is allowed, such as... Figure 5 When the measurement is started at position ②, the initial magnetic flux value is 0. The magnetic flux at position ③ has a maximum value, but this maximum value is much smaller than the measurement value starting from position ①. Similarly, a minimum value will appear when the measurement ends, and the value is negative. The total magnetic flux value is still the maximum magnetic flux value minus the minimum magnetic flux value, and the measurement result remains unchanged. Figure 4 This is the case with the starting position for structural measurements.

[0037] Since swapping the two terminals of the measuring coil will cause the measured value to change from positive to negative, the above analysis shows that swapping the coil terminals will cause the maximum magnetic flux to become the minimum and the minimum to become the maximum, and the sign of the total magnetic flux will also be reversed.

[0038] Example 2: External PLC for status detection and drive control This embodiment addresses dynamic measurement under complex operations such as automated loading and unloading on production lines. A characteristic of production lines is that the status detection of workstations and the motion control of workpieces are managed by one (or several) PLCs. When this dynamic measurement system is embedded in a production line, the loading, unloading, and movement control of the permanent magnet rotor are handled by the PLC, while the measurement process is still implemented by the system itself. During this process, the instrument communicates with the PLC via an RS485 interface to ensure seamless integration. In a practical application scenario: after the rotor body and magnetic material are assembled together, the rotor is fed into a magnetizing coil for magnetization. After magnetization, the rotor is pulled out of the magnetizing coil and sent to the next workstation, passing through a measuring coil. Dynamic measurement of the rotor's magnetic flux is completed during this passage through the measuring coil, with the added time being less than 2 seconds.

[0039] Step 1: Under PLC control, the permanent magnet rotor is loaded and magnetized by the magnetizing coil. After magnetization, the PLC sends a MODBUS-RTU protocol zeroing preparation instruction 01 06 10 31 00 02 5D04 to the dynamic measuring instrument via the RS485 interface, where 01 is the address of the measuring instrument, 06 is the write command, 10 31 is the register address, 00 02 is the zeroing preparation, and 5D 04 is the CRC16 checksum.

[0040] Step 2: After receiving the instruction, the measuring instrument discharges the integrating capacitor and resets the displayed value, maximum value, and minimum value to zero. Then, the PLC output signal directly controls the drive mechanism to push the permanent magnet rotor into the measuring coil assembly.

[0041] Step 3: Subsequently, the permanent magnet rotor passes through the measuring coil assembly, and the magnetic flux dynamic measuring instrument measures the maximum and minimum values ​​of the magnetic flux at high speed. The process is the same as steps 3 to 5 of Scheme 1. Step 4: When the PLC detects that the permanent magnet rotor has reached the termination position, it controls the mechanical structure to unload and at the same time sends the instruction 01 03 10 20 00 02 C1 01 to the magnetic flux dynamic measuring instrument via RS485 serial port to read the total magnetic flux measurement value. After receiving the data from the measuring instrument, the PLC will determine whether it is qualified and perform automatic sorting.

[0042] Example 3: PC industrial control computer communicates with magnetic flux dynamic measurement instrument via RJ45 to improve management This embodiment is suitable for networked computer systems and is a supplement to Embodiments 1 and 2. Each measuring instrument is configured with its own IP address. The PC industrial control computer can simultaneously collect magnetic flux measurement data pushed from different production lines, which facilitates subsequent unified data processing, storage and sharing.

[0043] After each measurement, the magnetic flux dynamic measuring instrument automatically sends the measurement results to a PC industrial control computer via the RJ45 port. The industrial control computer can collect the following information: IP address (corresponding to the production line), current time, magnetic flux measurement value, and permanent magnet rotor QR code. The QR code is typically scanned automatically before and after magnetization on the production line and can be read via the network. This unified collection and storage of basic information not only creates a file for each permanent magnet rotor but also provides data support for the timely detection of systemic faults.

[0044] In addition, the RJ45 interface provides a rich set of ASCII protocols, such as _value? for reading the total magnetic flux measurement value; _startup for zeroing preparation; _range=3 for setting the range to the third level 2000mWb; _out=0101 for setting the optocoupler output port, etc. By utilizing the communication function of RJ45, the entire measurement logic can be redefined through a PC industrial control computer, similar to a PLC.

[0045] Furthermore, this invention provides the beneficial effects of the system and method described herein compared to conventional magnetic flux dynamic products, specifically: 1. The extended extreme value measurement time window ensures accuracy while reducing the stringent requirements on instrument hardware; Previous designs for dynamic flux measurement coil assemblies referenced integrated magnetization measurement coil assemblies, with the coil height slightly exceeding the height of the permanent magnet rotor poles. For ease of distinction, these were referred to as static measurement coils. When a static measurement coil is used for dynamic measurement, the change in magnetic flux and the induced electromotive force on the measurement coil are as follows: Figure 6a As shown in the diagram, the interval between t0 and t1 represents the situation where the magnetic poles are just fully inside the measuring coil. At this point, the magnetic flux through the coil is at its maximum. We call the interval between t0 and t1 the extreme value measurement time window. Because the coil height is very close to the magnetic pole height, the magnetic poles quickly leave the measuring coil, and the curve changes towards t1. Due to the short time between t0 and t1, a very high measurement frequency is required to measure the maximum magnetic flux. This presents a trade-off between measurement accuracy and measurement frequency.

[0046] If the measurement frequency is not high enough, resulting in no sampling points between t0 and t1, or too few sampling points, the former will lead to an underestimation of the final measurement result, while the latter will make it difficult to eliminate interference (high-speed measurements are prone to generating interference points), causing uncertainty in the results. Therefore, in addition to using high-speed AD conversion measurement chips and high-frequency MCU chips in hardware, the bit depth of the AD conversion chip can be reduced through software configuration to achieve a higher conversion frequency. Although there are solutions, they all come at a cost and do not fundamentally solve the problem of a narrow time window for extreme value measurement.

[0047] This invention Figure 5In this process, the height of the measuring coil is significantly lower than the height of the permanent magnet rotor poles. This way, when the permanent magnet rotor poles rise from below until they just fill the coil, it is equivalent to... Figure 6b At point t0, the magnetic pole continues to rise. During this time, the measuring coil remains filled with the magnetic pole for a considerable period, during which the magnetic flux through the measuring coil changes almost no more, until the lower end of the magnetic pole leaves the lower edge of the coil. The time from when the magnetic pole fills the coil to when it begins to decrease is equivalent to... Figure 6b At point t1, continue moving upwards until the magnetic pole is completely away from the measuring coil to complete the measurement process.

[0048] It is easy to see that after the height of the measuring coil is reduced, the stable region of the maximum magnetic flux (between t0 and t1), i.e., the extreme value measurement time window, is significantly widened. In this way, many extreme value data can be measured without a particularly high measurement frequency, and there is no need to sacrifice accuracy by reducing the output bit depth of the AD conversion chip in exchange for stable measurement.

[0049] 2. Select an appropriate measuring coil height; Figure 7 The diagram illustrates several forms of measurement coil height relative to magnetic pole height, with dashed boxes representing the measurement coil and solid boxes representing the magnetic poles. Figure 7 The extreme value measurement window at position ② is as follows Figure 6a As shown, it is very narrow; while positions ①, ③, and ④ are significantly expanded, as... Figure 6b As shown. However, at position ④, the coil height is compressed too much, which can easily introduce new errors.

[0050] In practice, both positions ① and ③ can be used to customize the measuring coil. Whether to increase or decrease the coil height depends on the measurement accuracy and the specific requirements of coil manufacturing. Generally, position ① ensures higher accuracy, but the measuring coil assembly requires more space and materials; while position ③ offers slightly lower accuracy than position ①, but is easier to manufacture and can be cheaper. Furthermore, the extent of the t0 and t1 spacing extension is determined by the effective AD conversion rate, requiring minimal margin.

[0051] 3. The multi-functional design of the magnetic flux dynamic measurement instrument not only enables the implementation of a minimized dynamic system at low cost, but also allows for the use of open protocols suitable for measurement in various factory production lines. In addition to the basic function of dynamically measuring magnetic flux, the magnetic flux dynamic measuring instrument has a basic switch input / output interface that can sense motion status and control the measurement process. It can achieve a minimal dynamic measurement system at low cost without relying on other control instruments (such as PLC).

[0052] The flux dynamic measurement instrument provides an RJ485 serial interface and an RJ45 Ethernet interface. It provides fast flux measurement and can be easily integrated into the production line for real-time dynamic measurement. It can also be used for multi-instrument network measurement and data sharing.

[0053] about Figure 5 and Figure 7 It should be noted that the dashed box represents the measuring coil with two connected magnetic poles, and N and S represent a set of adjacent rotor magnetic poles.

[0054] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0055] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0056] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0057] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0058] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A system for dynamic measurement of magnetic flux in a permanent magnet rotor, characterized in that, include: Measuring coil assembly, drive mechanism, and flux dynamic measurement instrument; The measuring coil assembly is customized according to the shape and number of poles of the permanent magnet rotor being measured, and is used to generate a superimposed induced electromotive force when the permanent magnet rotor passes through it. The drive mechanism is used to move the permanent magnet rotor from one side of the measuring coil assembly to the other side at a constant speed; The magnetic flux dynamic measuring instrument is electrically connected to the measuring coil assembly, and is used to process the induced electromotive force signal, calculate the total magnetic flux of the permanent magnet rotor, and control the action of the drive mechanism.

2. The system for dynamic measurement of permanent magnet rotor flux according to claim 1, characterized in that, The measuring coil assembly includes multiple measuring coils and a multi-pole toroidal magnetic core. The number of measuring coils is equal to the number of magnetic poles of the permanent magnet rotor being measured, and all measuring coils are connected in series end to end. The winding directions of the measuring coils corresponding to the N pole and the S pole are opposite. All the measuring coils are fixedly mounted on the magnetic poles of the multi-pole toroidal magnetic core.

3. The system for dynamic measurement of permanent magnet rotor flux according to claim 2, characterized in that, The multi-pole toroidal core is made of laminated silicon steel sheets or soft magnetic materials.

4. The system for dynamic measurement of permanent magnet rotor flux according to claim 2, characterized in that, The measuring coil assembly is equipped with a positioning device and a guiding device to ensure that the N pole and S pole of the permanent magnet rotor being measured are aligned with the corresponding measuring coil.

5. The system for dynamic measurement of permanent magnet rotor flux according to claim 1, characterized in that, The magnetic flux dynamic measurement instrument includes: a coil interface, an integration unit, an AD conversion and data processing unit, a display unit, a communication interface, an I / O interface, and an MCU. The measurement coil assembly is connected to the coil interface, the coil interface is connected to the integration unit, the integration unit is connected to the AD conversion and data processing unit, the AD conversion and data processing unit is connected to the display unit, and the coil interface, integration unit, AD conversion and data processing unit, display unit, communication interface, and I / O interface are all connected to the MCU. The coil interface is used to receive analog signals acquired by the measurement coil assembly; The integral calculation unit is used to convert the induced electromotive force back into a magnetic flux analog signal; The AD conversion and data processing unit is used to convert the magnetic flux analog signal into a digital signal and perform digital filtering. The IO interface is used to sense the position or status information of the drive mechanism and output control signals to control the movement of the drive mechanism. The MCU is used to coordinate and control the operation of each part.

6. The system for dynamic measurement of permanent magnet rotor flux according to claim 5, characterized in that, The communication interface includes an RS485 interface and an RJ45 interface, which are used to communicate with an external programmable logic controller or industrial control computer to realize remote control of the measurement process and sharing of measurement data.

7. A method for dynamic measurement of magnetic flux in a permanent magnet rotor, applied to a system for dynamic measurement of magnetic flux in a permanent magnet rotor as described in any one of claims 1-6, characterized in that, include: Step 1: Load and position the permanent magnet rotor to the measurement start position, and trigger the dynamic measurement program; Step 2: Initialize the magnetic flux dynamic measurement instrument; Step 3: Output control signals through the IO interface to control the drive mechanism to move the permanent magnet rotor from the measurement start position to the measurement coil assembly at a constant speed until the measurement end position; Step 4: During the movement of the permanent magnet rotor, the measuring coil assembly generates a continuously changing superimposed induced electromotive force, which is transmitted to the magnetic flux dynamic measuring instrument. Step 5: The magnetic flux dynamic measurement instrument performs integration calculations and high-speed analog-to-digital conversion on the induced electromotive force, and records the minimum and maximum values ​​of magnetic flux in real time during the measurement process; Step 6: Calculate the total magnetic flux of the permanent magnet rotor under test based on the maximum and minimum magnetic flux values, and display the measurement results or output them through the communication interface; Step 7: After the measurement is completed, unload the permanent magnet rotor and restore the drive mechanism to its initial position.

8. The method for dynamic measurement of magnetic flux of a permanent magnet rotor according to claim 7, characterized in that, In step 2, the magnetic flux dynamic measurement instrument is initialized, specifically as follows: Discharge the integrating capacitor in the integrating unit of the magnetic flux dynamic measuring instrument, and reset the total magnetic flux value, maximum value, and minimum value displayed by the instrument to zero.

Images