A method for screening iron cores based on loss value simulation tests

Abstract

The present invention discloses a method for screening iron cores based on loss value simulation tests. The steps are as follows: S1. Place a single-turn closed-loop iron core on a test stand. The inherent saturation magnetic flux density of the iron core is B s , set the working magnetic flux density of the iron core as B m , and B m ≤B s ; S2. Pass the two test clips of the data acquisition device through both ends of the iron core and clamp them together inside the iron core, so that the clamped test clips remain inside the iron core; collect the series inductance Ls and quality factor Q of the iron core through the data acquisition device and record them as string information; S3. Connect the data processing device to the data acquisition device for communication, write and read the string information in step S2, and convert the string information into numerical information; S4. The data processing device reads the numerical information in step S3 and calculates the loss value P of the iron core at the working magnetic flux density B m value based on calculation formula A; S5. Screen out the iron cores with the loss value P calculated in step S4 within the range of the loss value P.

Description

Technical Field

[0001] The present invention relates to the technical field of iron core screening methods, and particularly to a method for screening iron cores based on simulated loss value testing. Background Art

[0002] As the core component of a magnetic device, the loss of the iron core directly affects the efficiency and temperature rise of the device. The size of the iron core loss directly affects the design of the device. Especially when designing a transformer, the iron core loss must be specified within a specific range, otherwise it will directly affect the conversion efficiency of the transformer. In practical applications, in order to better achieve product performance, it is necessary to screen out iron cores that meet the requirements. Therefore, it is necessary to first simulate the loss value of the iron core under a certain working magnetic flux density state, and then select the iron cores that meet the requirements of the loss value range.

[0003] At present, the iron core loss simulation test scheme is relatively complex. It is necessary to test multiple sets of data such as inductance, impedance, and frequency to obtain the loss value, and the calculation is relatively complex, and the test speed is slow.

[0004] On the other hand, there are few instruments used in the current iron core loss simulation test scheme on the market. Most of them adopt the method of measurement plus calculation. Because the instruments that can measure the iron core loss value are expensive and cannot meet the rapid test of production. For example, the "MATS-2010SA Soft Magnetic DC Measurement Device" produced by Hunan Lianzhong has a market price of 150,000 yuan per unit, the Japanese Iwasaki BH analyzer, and the "SY-8219 and SY-8218 Soft Magnetic AC Characteristic Tests" are about 500,000 - 2 million yuan according to different frequency and power configurations. The measurement loss speed of the Hunan Lianzhong MATS-2010SA is about 20 seconds per time, and the measurement loss speed of the SY-8219 and SY-8218BH of the Japanese Iwasaki is about 90 seconds per time.

[0005] An LCR tester is an instrument that can measure inductance, capacitance, and impedance. However, when applying the LCR tester to the simulation test of the iron core loss value, it is necessary to solve the problem of collecting the measurement value of the instrument to the computer for program operation. This is because the instrument equipment manufacturer does not provide the acquisition program code, but the instrument provides a data interface. Therefore, in order to perform secondary development operations and collect the test value of the instrument to the computer through the data interface, it is necessary to specifically write an acquisition program. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for screening iron cores based on simulated loss value testing to overcome the deficiencies of the prior art, provide a scheme for quickly screening out iron cores that meet the requirements, solve the problems of complex screening steps, slow data acquisition speed, high data acquisition cost, and data acquisition in secondary development operations existing in the prior art, avoid various deficiencies of manual data input, and at the same time, there is no need to purchase new equipment, saving costs.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for screening iron cores based on loss value simulation tests, comprising the following steps

[0009] S1. Place the single-turn closed-loop iron core on the test stand. The inherent saturation magnetic flux density of the iron core is B s , and set the working magnetic flux density of the iron core to be B m , and B m ≤B s ;

[0010] S2. Pass the two test clips of the data acquisition device through both ends of the iron core and clamp them to each other inside the iron core, so that the clamped test clips remain inside the iron core; collect the series inductance Ls and quality factor Q of the iron core through the data acquisition device, and record them as string information;

[0011] S3. Connect the data processing device to communicate with the data acquisition device, write the string information in step S2 into the data processing device, read it through the data processing device, and convert the string information into numerical information;

[0012] S4. The data processing device reads the numerical information in step S3, and based on calculation formula A, calculates the loss value P of the iron core at the working magnetic flux density B m value. The calculation formula A is as follows:

[0013]

[0014] In the formula, B m is the working magnetic flux density, Ls is the inductance of the iron core, Le is the equivalent length of the iron core magnetic circuit, Ae is the equivalent cross-sectional area of the iron core, Q is the quality factor of the iron core, π is the circumference ratio, ρ is the density of the iron core, and f is the set frequency of the data acquisition device.

[0015] S5. Based on the set loss value P range, screen out the iron cores with the loss value P calculated in step S4 within the loss value P range.

[0016] In the present invention, the data processing device converts the string information of the data acquisition device into numerical information, and then performs secondary development operations on the numerical information. At the same time, combined with the calculation formula, only by obtaining the numerical information of the inductance Ls and the quality factor Q, the loss value P of the iron core under the state of the working magnetic flux density B m can be obtained, so as to quickly screen out the iron cores that meet the requirements, and make the loss value P of the screened iron cores within the specified range.

[0017] Furthermore, a data acquisition program for converting string information into numerical information is set in the data processing device.

[0018] Furthermore, step S3 includes the following steps. The settings of the communication port, baud rate, and bit rate on the working interface of the data acquisition program are the same as those of the data acquisition device, so that the data processing device is communicatively connected to the data acquisition device.

[0019] Furthermore, step S3 also includes:

[0020] S31. After writing the string information of the data acquisition device into the data acquisition program, the data acquisition program reads the string information.

[0021] S32. The data acquisition program splits the string information into two segments of string information, and a delimiter is set between the two segments of string information. The string information before the delimiter is the string information of the series inductance Ls, and the string information after the delimiter is the string information of the quality factor Q.

[0022] S33. Convert the string information of the series inductance Ls in step S32 into the numerical information of the series inductance Ls; convert the string information of the quality factor Q in step S32 into the numerical information of the quality factor Q.

[0023] S34. Display the numerical information obtained in step S33 through a display control.

[0024] Furthermore, a total amount of string information is also set in step S31, and the reading stops after the total amount of string information is read.

[0025] Furthermore, in step S32, a first string length X1 and a second string length X2 are set. The length of the string information is separated into two lengths of string information by the delimiter. The length of the string information before the delimiter is the first string length X1, and the length of the string information after the delimiter is the second string length X2. First, read the string information with the first string length X1 before the delimiter and record it as the string information of the series inductance Ls, and then read the string information with the second string length X2 after the delimiter and record it as the string information of the quality factor Q.

[0026] Furthermore, a verification method for the first string length X1 and the second string length X2 is also included. The verification method includes: first setting a first preset string length X 10 and a second preset string length X 20 , through the first preset string length X10 and the second preset string length X 20 Split the string information to obtain two segments of string information. Set the string information before the delimiter as the first string information, and the string information after the delimiter as the second string information. Then convert the first string information and the second string information into the first numerical information and the second numerical information respectively, and then determine whether the first numerical information and the second numerical information are equal to the numerical value of the series inductance Ls and the numerical value of the quality factor Q displayed on the data acquisition device. When the judgment is yes, then the first preset string length X 10 is the first string length X1 and the second preset string length X 20 is the second string length X2. When the judgment is no, then modify the length value of the first preset string length X 10 and the length value of the second preset string length X 20 and conduct the inspection again.

[0027] Furthermore, in step S33, convert the string information with the length of the first string length X1 in the string information into numerical information, that is, obtain the numerical information of the series inductance Ls; convert the string information with the length of the second string length X2 in the string information into numerical information, that is, obtain the numerical information of the quality factor Q.

[0028] Furthermore, to reduce the test cost of the present invention, the data acquisition device is an LCR tester. The LCR digital bridge is equipped with data interfaces, such as: RS232, RS485, GPIB interface, USB interface, etc.

[0029] Advantages of the present invention:

[0030] 1. The present invention converts the string information of the data acquisition device into numerical information through the data processing device, and then performs secondary development operations on the numerical information. At the same time, in combination with the calculation formula, only the numerical information of the inductance Ls and the numerical information of the quality factor Q need to be obtained to obtain the loss value P of the iron core under the working magnetic flux density of B m so as to quickly screen out the iron cores that meet the requirements, and make the loss value P of the screened iron cores within the specified range.

[0031] 2. Through the data acquisition program, the test values of the data acquisition device are collected to the computer through the data interface for secondary development operations, solving the problem of collecting the measured values of the data acquisition device to the computer for program operations. The data acquisition program runs stably and quickly.

[0032] 3. The present invention uses an LCR tester as the data acquisition device, reducing the test cost. Description of the Drawings

[0033] Figure 1 Schematic diagram of the program working interface in an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the second program working interface in an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the third program working interface in an embodiment of the present invention. Detailed implementation manners

[0036] In order to make the technical solutions, objectives and advantages of the present invention clearer and more understandable, the present invention will be further explained below with reference to the accompanying drawings and embodiments.

[0037] A method for screening iron cores based on loss value simulation tests includes the following steps:

[0038] S1. Place the single-turn closed-loop iron core on the test stand. The inherent saturation magnetic flux density of the iron core is B s , and set the working magnetic flux density of the iron core to B m , and B m ≤B s ;

[0039] S2. Pass the two test clips of the data acquisition device through the two ends of the iron core and clamp them to each other so that the clamped test clips remain inside the iron core; collect the series inductance Ls and quality factor Q of the iron core through the data acquisition device and record them as string information;

[0040] In this embodiment, the data acquisition device is an LCR tester, specifically a TH2816A bridge. Its communication port is COM3, the baud rate is set to 9600, and the data bit is 8. At this time, after calibrating and debugging the TH2816A bridge, set the test item to the Ls-Q test page and zero the TH2816A bridge for open and short circuits.

[0041] S3. Connect the data processing device to communicate with the data acquisition device. Specifically, a data acquisition program for converting string information into numerical information is set in the data processing device. Before the test starts, turn on the power of the TH2816A bridge, turn on the computer, and open the working interface of the data acquisition program set in the data processing device. As Figure 1 shown, select the "Data Acquisition" page, select the communication port as COM3, set the baud rate to 9600, and the data bit to 8. The above technical parameters are kept consistent with the technical parameter settings of the LCR tester. Use a transmission line to perform serial communication between the data acquisition device and the data processing device to achieve communication between the serial port of the data acquisition device and the data processing device.

[0042] Then write the string information in step S2 into the data processing device, read it by the data processing device, and convert the string information into numerical information. Specifically, it includes the following steps:

[0043] S31. After writing the string information of the data acquisition device into the data acquisition program, the data acquisition program reads the string information. To prevent the data acquisition program from repeatedly writing the string information, a total amount of string information is set in this step. After reading the total amount of string information, the reading stops, which can further improve the operation speed and avoid system crashes.

[0044] S32. The data acquisition program splits the string information into two segments of string information, and a delimiter is set between the two segments of string information. The string information before the delimiter is the string information of the series inductance Ls, and the string information after the delimiter is the string information of the quality factor Q. Specifically, a first string length X1 and a second string length X2 are set. The length of the string information is separated into two lengths of string information by the delimiter. The length of the string information before the delimiter is the first string length X1, and the length of the string information after the delimiter is the second string length X2. First, read the string information of the first string length X1 before the delimiter and record it as the string information of the series inductance Ls, and then read the string information of the second string length X2 after the delimiter and record it as the string information of the quality factor Q.

[0045] Before testing, it is necessary to verify the first string length X1 and the second string length X2. The verification method includes: first setting a first preset string length X 10 and a second preset string length X 20 , splitting the string information into two segments of string information through the first preset string length X 10 and the second preset string length X 20 , setting the string information before the delimiter as the first string information, setting the string information after the delimiter as the second string information, and converting the first string information and the second string information into a first numerical information and a second numerical information respectively, and then determining whether the first numerical information and the second numerical information are equal to the values of the series inductance Ls and the quality factor Q displayed on the data acquisition device. When the judgment is yes, the first preset string length X 10 is the first string length X1, and the second preset string length X 20 is the second string length X2. When the judgment is no, modify the length value of the first preset string length X 10 and the second preset string length X20 Length value and check again.

[0046] S33, converting the string information of the series inductance Ls in step S32 into the numerical information of the series inductance Ls; converting the string information of the quality factor Q in step c into the numerical information of the quality factor Q; specifically, converting the string information whose length is the first string length X1 into the numerical information, i.e., obtaining the numerical information of the series inductance Ls; converting the string information whose length is the second string length X2 into the numerical information, i.e., obtaining the numerical information of the quality factor Q.

[0047] S34, displaying the numerical information obtained in step S33 through a display control.

[0048] Step S3 is as follows: Figure 2 As shown, select the "Parameter Input" page in the program, input the equivalent cross-sectional area Ae of the core, the equivalent length Le of the core magnetic circuit, and the density ρ of the core; Figure 3 As shown in the program working interface, select the page "Loss Test" and set the working magnetic flux density B m Value and frequency f, the frequency f must be consistent with the frequency of the TH2816A bridge. Click "Start Test" to obtain the numerical information of the series inductance Ls and the numerical information of the quality factor Q.

[0049] S4, the data processing device reads the numerical information of step S3, and calculates the working magnetic flux density B of the iron core based on the calculation formula A. m The loss value P under the value is calculated by the following formula A:

[0050]

[0051] In the formula, B m is the working magnetic flux density, Ls is the inductance of the iron core, Le is the equivalent length of the iron core magnetic circuit, Ae is the equivalent cross-sectional area of the iron core, Q is the quality factor of the iron core, π is the pi, ρ is the density of the iron core, and f is the set frequency of the data acquisition device.

[0052] Through the calculation of the above formula, the working magnetic flux density B of the core is obtained. m The loss value under the value is displayed on the "Loss Test" page in the working interface, and the core can be read at this working magnetic flux density B. m The loss value P is set to 0. At this point, the test is completed and click "Stop Test".

[0053] S5. Based on the set loss value P range, the iron cores whose loss values P calculated in step S4 are within the loss value P range are screened out.

[0054] According to the above test method, due to production process or product design requirements, it is necessary to select iron cores with loss value P within the range shown in the following table at the set working magnetic flux density B m and frequency f:

[0055] Item Value 1 Value 1 Value 1 <![CDATA[Set the working magnetic flux density B m (T)]]> 0.5T 0.4T 0.3T Frequency f (KHz) 20 KHz 30 KHz 40 KHz Loss value P (W / Kg) P<30 P<40 P<35

[0056] Select samples 1, 2, 3, 4, and 5 for screening. The above samples 1, 2, 3, 4, and 5 are all single-turn toroidal iron cores with external dimensions of 28 cm * 19 cm * 10 cm. The equivalent cross-sectional area Ae, equivalent magnetic path length Le, and density ρ of each sample are shown in the following table:

[0057] Group Equivalent magnetic path length Le (cm) Equivalent cross-sectional area Ae (cm^2) Density ρ of the iron core (g / cm^3) Sample 1 7.38 0.36 7.3 Sample 2 7.38 0.36 7.3 Sample 3 7.38 0.36 7.3 Sample 4 7.38 0.36 7.3 Sample 5 7.38 0.36 7.3

[0058] Simulate the loss value of the above samples 1, 2, 3, 4, and 5 at different frequencies and different working magnetic flux densities according to calculation formula A. The results are shown in the following table:

[0059]

[0060] The above results show that the screening method of this embodiment only takes 0.4 seconds for each sample to obtain the numerical information of the loss value of the iron core at the set working magnetic flux density. According to the obtained numerical information of the loss value, the iron cores falling within the set loss value range are screened out. The present invention converts the string information of the data acquisition device into numerical information through a data processing device, and then performs secondary development operations on the numerical information. At the same time, combined with the calculation formula, only the numerical information of the inductance Ls and the quality factor Q needs to be obtained to obtain the numerical information of the loss value of the iron core at the set working magnetic flux density, so as to quickly screen out the iron cores that meet the requirements.

[0061] The above is only the preferred embodiment of the present invention. For those skilled in the art of this technology, without departing from the implementation principle of the present invention, the above embodiments can still be modified, and the corresponding modification schemes should also be regarded as the protection scope of the present invention.

Claims

1. A method for screening iron cores based on loss value simulation tests, characterized in that: Including the following steps, S1. Place the single-turn closed-loop iron core on the test stand. The inherent saturation magnetic flux density of the iron core is B s , and set the working magnetic flux density of the iron core to B m , and B m ≤ B s ; S2. Insert the two test clips of the data acquisition device through both ends of the iron core into the iron core and clamp them together, so that the clamped test clips remain in the iron core; collect the series inductance Ls and quality factor Q of the iron core through the data acquisition device, and record them as string information; S3. Connect the data processing device to the data acquisition device in communication, write the string information in step S2 into the data processing device, read it through the data processing device, and convert the string information into numerical information; S4. The data processing device reads the numerical information in step S3 and calculates the loss value P of the iron core at the working magnetic flux density B value based on the calculation formula A. The calculation formula A is as follows: m ​ where B m is the working magnetic flux density, Ls is the inductance of the iron core, Le is the equivalent length of the magnetic circuit of the iron core, Ae is the equivalent cross-sectional area of the iron core, Q is the quality factor of the iron core, π is the pi, ρ is the density of the iron core, and f is the frequency of the set data acquisition device; S5. Based on the set loss value P range, screen out the iron cores with the loss value P calculated in step S4 within the loss value P range.

2. The method for screening iron cores based on loss value simulation tests as described in claim 1, wherein, A data acquisition program for converting string information into numerical information is set in the data processing device.

3. The method for screening iron cores based on loss value simulation test according to claim 2, step S3 includes the following steps. The settings of the communication port, baud rate, and bit rate on the working interface of the data acquisition program are the same as those of the data acquisition device, so that the data processing device is connected to the data acquisition device in communication.

4. The method for screening iron cores based on loss value simulation tests as described in claim 3, characterized in that, Step S3 further includes: S31. After writing the string information of the data acquisition device into the data acquisition program, the data acquisition program reads the string information; S32. The data acquisition program splits the string information into two segments of string information, and a separator is set between the two segments of string information. The string information before the separator is the string information of the series inductance Ls, and the string information after the separator is the string information of the quality factor Q; S33. Convert the string information of the series inductance Ls in step S32 into the numerical information of the series inductance Ls; convert the string information of the quality factor Q in step S32 into the numerical information of the quality factor Q; S34. Display the numerical information obtained in step S33 through a display control.

5. The method for screening iron cores based on loss value simulation tests according to claim 4, characterized in that, In step S31, the total amount of string information is also set, and the reading stops after reading the total amount of string information.

6. The method for screening iron cores based on loss value simulation tests as described in claim 4, wherein, In step S32, a first string length X1 and a second string length X2 are set. The length of the string information is separated into two lengths of string information by the separator. The length of the string information before the separator is the first string length X1, and the length of the string information after the separator is the second string length X2. First, read the string information with the first string length X1 before the separator and record it as the string information of the series inductance Ls, and then read the string information with the second string length X2 after the separator and record it as the string information of the quality factor Q.

7. The method for screening iron cores based on loss value simulation tests as described in claim 6, wherein It also includes a verification method for the first string length X1 and the second string length X2. The verification method includes: first setting a first preset string length X 10 and a second preset string length X 20 . By using the first preset string length X 10 and the second preset string length X 20 , the string information is split into two segments of string information. The string information before the delimiter is set as the first string information, the string information after the delimiter is set as the second string information, and the first string information and the second string information are respectively converted into the first numerical information and the second numerical information. Then, it is determined whether the first numerical information and the second numerical information are equal to the values of the series inductance Ls and the quality factor Q displayed on the data acquisition device. When the determination is yes, the first preset string length X 10 is the first string length X1, and the second preset string length X 20 is the second string length X2. When the determination is no, the length values of the first preset string length X 10 and the second preset string length X 20 are modified, and the verification is performed again.

8. The method for screening iron cores based on loss value simulation tests as described in claim 6, wherein In step S33, convert the string information with the first string length X1 into numerical information, that is, obtain the numerical information of the series inductance Ls; convert the string information with the second string length X2 into numerical information, that is, obtain the numerical information of the quality factor Q.

9. The method for screening iron cores based on loss value simulation tests as described in claim 1, characterized in that The data acquisition device is an LCR tester.

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