A method and system for online monitoring of inductance of inductor devices

Abstract

The present invention relates to the field of data processing technology, and specifically to a method and system for online monitoring the inductance of an inductor device, comprising: determining the magnetic leakage ratio of the inductor device at the current moment based on the proportion of the core insertion length in the coil length at the current moment, combined with the minimum and maximum magnetic leakage ratios, then determining the effective change in the magnetic permeability of the core of the inductor device at the current moment, determining the effective total magnetic resistance of the electromagnetic device at the current moment based on the vacuum magnetic permeability, the coil length, the relative magnetic permeability and cross-sectional area of ​​the core, and the core insertion length at the current moment, combined with the effective change, and determining the true effective inductance of the inductor device at the current moment based on the effective total magnetic resistance and the number of coil turns, combined with the magnetic leakage ratio of the inductor device at the current moment. The present invention improves the accuracy of online monitoring of the inductance of the inductor device.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular to an online monitoring method and system for the inductance of an inductor device. Background Art

[0002] In modern power electronics systems, inductors, as key components, are widely used in power conversion and control. Their energy storage and ability to suppress sudden current fluctuations make them irreplaceable for stabilizing circuit operation and optimizing power quality. Changes in inductor inductance directly impact the performance of power electronics systems. To meet circuit requirements, inductors with adjustable inductance are being developed. Online monitoring of inductor inductance is crucial for their application.

[0003] Existing Problem: For inductors with adjustable inductance, the monitoring accuracy of their inductance needs to be even higher. Existing inductor monitoring methods generally calculate theoretical values ​​based on the inductor structure and then make corrections. However, the current inductor structure is variable, so the existing theoretical inductance calculation formula has deviations. Furthermore, the variable inductor structure causes the influence of magnetic leakage and core temperature on the actual inductance to continuously change, resulting in even greater deviations in the inductor's inductance. Summary of the Invention

[0004] The present invention provides an online monitoring method and system for the inductance of an inductor device to solve the existing problems.

[0005] The present invention provides an online monitoring method and system for the inductance of an inductor device using the following technical solutions:

[0006] An embodiment of the present invention provides a method for online monitoring of the inductance of an inductor device, the method comprising the following steps:

[0007] Obtain vacuum magnetic permeability, minimum and maximum magnetic leakage ratios of inductors, coil length, number of coil turns, relative magnetic permeability of the core, cross-sectional area of ​​the core, Curie temperature of the core, base temperature of the core, and the current core insertion length and current value;

[0008] Determine the magnetic leakage ratio of the inductor at the current moment based on the ratio of the core insertion length to the coil length at the current moment and the minimum and maximum magnetic leakage ratios;

[0009] Determine the effective change in the magnetic permeability of the core of the inductor at the current moment based on the current value at the current moment, the core temperature value output from a pre-established positive correlation function of the core temperature and current, the difference between the Curie temperature of the core and the reference temperature, and the vacuum permeability, the relative permeability of the core, and the proportion of the core insertion length in the coil length;

[0010] The effective total magnetic resistance of the electromagnetic device at the current moment is determined based on the vacuum magnetic permeability, coil length, relative magnetic permeability and cross-sectional area of ​​the iron core, and the iron core insertion length at the current moment, in combination with the effective change. The actual effective inductance of the inductor device at the current moment is determined based on the effective total magnetic resistance and the number of coil turns, in combination with the magnetic leakage ratio of the inductor device at the current moment.

[0011] Furthermore, the determining of the magnetic leakage ratio of the inductor device at the current moment includes the following specific steps:

[0012] Get the ratio of the core insertion length to the coil length at the current moment, and record it as the proportion of the core insertion length at the current moment;

[0013] Obtain the difference between the maximum magnetic leakage ratio and the minimum magnetic leakage ratio, and record it as the total variation range of magnetic leakage;

[0014] The product of the current core insertion length ratio and the total variation range of the magnetic leakage is obtained as the third product. The difference between the maximum magnetic leakage ratio and the third product is subtracted and recorded as the magnetic leakage ratio of the inductor at the current moment.

[0015] Furthermore, the determining of the effective change in the magnetic permeability of the core of the inductor device at the current moment includes the following specific steps:

[0016] Obtain the current value of the inductor device at the current moment, input it into the core temperature value output by the positive correlation function of the core temperature and current, and record it as the target core temperature value;

[0017] Determine the effective temperature change at the current moment based on the target core temperature value, the core reference temperature, and the core Curie temperature;

[0018] Determine the change in magnetic permeability of the core of the inductor at the current moment based on the relative magnetic permeability of the vacuum and the core and the effective amplitude of the temperature change at the current moment;

[0019] The product of the proportion of the core insertion length at the current moment and the change in the magnetic permeability of the inductor core at the current moment is recorded as the effective change in the magnetic permeability of the inductor core at the current moment.

[0020] Furthermore, the step of determining the effective amplitude of the temperature change at the current moment based on the target core temperature value, the core reference temperature, and the core Curie temperature includes the following specific steps:

[0021] Obtain the difference between the target core temperature and the core reference temperature, and record it as the change in core temperature caused by the current at the current moment;

[0022] Obtain the difference between the Curie temperature of the core and the base temperature of the core, and record it as the temperature change amplitude that produces the change in magnetic permeability;

[0023] The ratio of the change in core temperature caused by the current at the current moment to the temperature change amplitude that produces the change in magnetic permeability is recorded as the effective amplitude of the temperature change at the current moment.

[0024] Furthermore, the step of determining the change in magnetic permeability of the core of the inductor device at the current moment based on the relative magnetic permeability of the vacuum and the core and the effective amplitude of the temperature change at the current moment includes the following specific steps:

[0025] The product of vacuum magnetic permeability, relative magnetic permeability of the iron core and a preset threshold coefficient is recorded as the magnetic permeability threshold;

[0026] The product of the magnetic permeability threshold and the effective amplitude of the temperature change at the current moment is recorded as the change in the magnetic permeability of the iron core of the inductor device at the current moment.

[0027] Furthermore, the determining of the effective total magnetic resistance of the electromagnetic device at the current moment includes the following specific steps:

[0028] Determine the magnetic resistance of the air portion at the current moment based on the vacuum magnetic permeability, the cross-sectional area of ​​the core, the coil length, and the core insertion length at the current moment;

[0029] Determine the effective magnetic resistance of the core at the current moment based on the vacuum magnetic permeability, the relative magnetic permeability of the core, the cross-sectional area of ​​the core, the core insertion length at the current moment, and the effective change in the magnetic permeability of the core of the inductor at the current moment;

[0030] The sum of the effective magnetic resistance of the iron core part at the current moment and the magnetic resistance of the air part at the current moment is recorded as the effective total magnetic resistance of the electromagnetic device at the current moment.

[0031] Furthermore, the magnetic resistance of the air portion at the current moment is determined based on the vacuum magnetic permeability, the cross-sectional area of ​​the iron core, the coil length, and the iron core insertion length at the current moment, including the following specific steps:

[0032] Obtain the difference between the coil length and the core insertion length at the current moment, and record it as the length of the air portion at the current moment;

[0033] The product of the vacuum magnetic permeability and the cross-sectional area of ​​the iron core is obtained and recorded as the second product. The ratio of the length of the air portion at the current moment to the second product is recorded as the magnetic resistance of the air portion at the current moment.

[0034] Furthermore, the method of determining the effective magnetic resistance of the core portion at the current moment based on the vacuum magnetic permeability, the relative magnetic permeability of the core, the cross-sectional area of ​​the core, the core insertion length at the current moment, and the effective change in the magnetic permeability of the core of the inductor device at the current moment includes the following specific steps:

[0035] Obtain the difference between the product of the vacuum magnetic permeability and the relative magnetic permeability of the iron core and the effective change in the magnetic permeability of the iron core of the inductor device at the current moment as the effective magnetic permeability of the iron core at the current moment;

[0036] The product of the effective magnetic permeability of the iron core at the current moment and the cross-sectional area of ​​the iron core is obtained, which is recorded as the fourth product. The ratio of the iron core insertion length at the current moment to the fourth product is recorded as the effective magnetic resistance of the iron core part at the current moment.

[0037] Furthermore, the determining of the real effective inductance of the inductor device at the current moment includes the following specific steps:

[0038] The ratio of the square of the number of coil turns to the effective total magnetic resistance of the electromagnetic device at the current moment is recorded as the effective inductance of the inductor at the current moment;

[0039] The product of the inverse proportional value of the magnetic leakage ratio of the inductor device at the current moment and the effective inductance of the inductor device at the current moment is recorded as the real effective inductance of the inductor device at the current moment.

[0040] The present invention also proposes an online monitoring system for the inductance of an inductive device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program stored in the memory to implement the steps of the aforementioned method for online monitoring the inductance of an inductive device.

[0041] The beneficial effects of the technical solution of the present invention are as follows: first, the inductance is calculated using the coil and magnetic resistance, and the core and air portions are converted into series magnetic resistance. Based on the series magnetic resistance, the actual magnetic resistance of the entire inductor device is determined, facilitating accurate calculation of the theoretical inductance of the inductor device at any time. Then, based on the theoretical inductance, the influence of the core insertion length on magnetic leakage and core temperature is taken into account, and different corrections are made to the theoretical inductance at any time and for any insertion length. This effectively combines the operating logic of the variable inductor device and further improves the accuracy of inductance monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is a flowchart of the steps of an online monitoring method for the inductance of an inductor device according to the present invention;

[0044] Figure 2 This is the first schematic diagram of the inductor device structure;

[0045] Figure 3 This is the second schematic diagram of the inductor device structure;

[0046] Figure 4 This is the third schematic diagram of the inductor device structure. DETAILED DESCRIPTION

[0047] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effectiveness of a method and system for online monitoring of the inductance of an inductor device proposed in accordance with the present invention. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0048] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0049] The following describes in detail a method and system for online monitoring of the inductance of an inductor device provided by the present invention with reference to the accompanying drawings.

[0050] See also Figure 1 , which shows a flowchart of a method for online monitoring of the inductance of an inductor device provided by one embodiment of the present invention, the method comprising the following steps:

[0051] Step S001: Obtain vacuum magnetic permeability, minimum and maximum magnetic leakage ratios of the inductor, coil length, number of coil turns, relative magnetic permeability of the core, cross-sectional area of ​​the core, Curie temperature of the core, reference temperature of the core, and current core insertion length and current value.

[0052] It should be noted that the inductance of an inductor is its core parameter. The inductance is generally determined by the material and device structure. The key factors affecting the inductance are the magnetic circuit structure, number of turns, magnetic permeability, etc. Therefore, after the material and structure of the device are generally determined, the inductance of the inductor does not change. However, in practice, inductors with variable inductance are often required. For example, the inductance can be adjusted by separating the iron core and the coil and adjusting the length of the iron core inserted into the coil. The first schematic diagram of the inductor structure is as follows: Figure 2 As shown in the second diagram of the inductor structure, Figure 3 The third diagram of the inductor structure is as shown in Figure 4 As shown. Figure 2 、 Figure 3 as well as Figure 4 In the embodiment, an inductor assembly 2 and an adjustment assembly 3 are installed inside the body 1. The inductor assembly 2 includes an insulating tube 201 installed inside the body 1. A coil 203 is wound around the outside of the insulating tube 201. The insulating tube 201 is located on the side of the iron core 302 away from the moving block 301. The diameter of the insulating tube 201 is larger than the diameter of the iron core 302. A baffle 202 is installed on the outside of the insulating tube 201. The outer wall of the baffle 202 is fixedly connected to the inner wall of the body 1. The adjustment assembly 3 includes a moving block 301 slidably connected to the inside of the body 1. An iron core 302 is installed on one side of the moving block 301. A screw groove 305 is provided on the other side of the iron core 302. A screw rod 306 is connected to the inner thread of the screw groove 305. The output shaft of a motor 307 is installed on one end of the screw rod 306. The outer side of the motor 307 is fixedly connected to the body 1. The motor 307 is externally connected to the power supply. A limiting member is installed on the outside of the moving block 301, and the limiting member includes a slider 304 installed at an equal angle on the outside of the moving block 301, the slider 304 is slidably connected to the inside of the slide groove 303, and the slide groove 303 is opened at an equal angle on the inner wall of the body 1, a sleeve 308 is installed on the inner wall of the body 1, and a pressure sensor 309 is installed at one end of the inner wall of the sleeve 308. The sleeve 308 is located on the side of the moving block 301 away from the iron core 302, and a movable block 310 is slidably connected to the inside of the sleeve 308. A connecting rod 311 is installed on one side of the movable block 310, one end of the connecting rod 311 is fixedly connected to the moving block 301, and a spring 312 is installed on the other side of the movable block 310, one end of the spring 312 is fixedly connected to the pressure sensor 309, the pressure sensor 309 signal is connected to a receiver, and a battery is installed in the pressure sensor 309.

[0053] It should be further explained that the inductance of an inductor is proportional to the square of the number of coil turns, but is also affected by the internal magnetic resistance of the coil, which is inversely proportional to the inductance. Since the inductance of an inductor is mainly affected by the structure and material of the inductor, the number of coil turns and the internal magnetic resistance of the coil are the main determining factors. In addition, during the actual use of the inductor, the temperature affects the magnetic permeability of the iron core inside the coil, which in turn affects the internal magnetic resistance of the coil, thereby affecting the inductance of the inductor. And the above-mentioned inductor adjusts the inductance by moving the iron core. Therefore, when performing the inductance monitoring of the above-mentioned inductor, it is necessary to first record the value of the pressure sensor to reflect the length of the iron core inserted into the coil, and at the same time record the current passing through the coil to reflect the heating of the iron core. The recorded data is uploaded to the inductance monitoring platform, where the data recording time interval is uniformly 1 second, and this example is used for description.

[0054] Thus, the vacuum magnetic permeability, relative magnetic permeability of air, minimum and maximum magnetic leakage ratio of the inductor, rated current range, coil length, number of coil turns, relative magnetic permeability of the core, cross-sectional area of ​​the core, Curie temperature of the core, base temperature of the core, spring constant, as well as the core insertion length, pressure value, current value, and core temperature value at each moment can be obtained.

[0055] Among them, the vacuum permeability for H / m (henry per meter), is pi, the relative magnetic permeability of air , which is a known data. The minimum and maximum magnetic leakage ratio of inductor components and (In this embodiment, the magnetic leakage ratio ranges from 0 to 1), rated current range ( and are the minimum and maximum values ​​within the rated current range respectively), coil length , coil turns , relative magnetic permeability of the core , cross-sectional area of ​​the core , Curie temperature of the iron core , the reference temperature of the core (Specifically 25 degrees Celsius), spring constant , which can be obtained from the product manual provided by the manufacturer. Using pressure, current, and temperature sensors, the pressure, current, and core temperature of the inductor can be collected in real time at each moment. The core insertion length of the inductor at each moment can be expressed based on the value of the pressure sensor. During the core insertion process, the pressure of the spring on the pressure sensor changes. Based on the pressure value, the spring compression can be obtained, and thus the core insertion length can be obtained. The spring compression at the current moment ,in is the pressure value of the inductor at the current moment, is the spring constant. It is known that the spring is compressed when the iron core is inserted into the coil, so the compression of the spring is the length of the iron core inserted into the coil. Therefore, the spring compression at the current moment is As the core insertion length of the inductor at the current moment .

[0056] Step S002: determining the magnetic leakage ratio of the inductor at the current moment according to the ratio of the core insertion length to the coil length at the current moment and combining the minimum and maximum magnetic leakage ratios.

[0057] It should be noted that the inductance of an inductor is theoretically stable under the determination of its structure and materials. The above-mentioned adjustable inductor structure is achieved by changing the length of the iron core inserted into the coil. The principle is to change the total magnetic resistance inside the coil. The essence of inductance is directly related to the total magnetic resistance of the magnetic circuit, that is, the inductance is inversely proportional to the total magnetic resistance. In the process of inserting the iron core into the coil, it is often mistakenly believed that only the iron core part generates inductance, so the actual insertion length is calculated as the effective length, and the inductance of the inductor is directly calculated. However, in reality, the air part that is not inserted into the iron core can also form magnetic flux, thereby affecting the inductance of the inductor. Therefore, the calculation formula for the change of inductance with the insertion length of the iron core needs to be derived in combination with the series model of the magnetic circuit. The core is to describe the relationship between inductance and insertion length through the change of total magnetic resistance.

[0058] Preferably, in one embodiment of the present invention, the method for obtaining the magnetic leakage ratio of the inductor device at the current moment includes:

[0059] The magnetic circuit consists of an iron core part and an air part in series. The iron core insertion length at the current moment is The magnetic permeability of the core is , the length of the air part at the current moment is (the part of the coil not occupied by the core), the magnetic permeability of the air part is , due to the relative magnetic permeability of air , so the magnetic permeability of the air part can be expressed as .

[0060] It should be noted that magnetic resistance refers to the obstruction of the magnetic circuit to the magnetic field, which mainly depends on the magnetic circuit length, magnetic permeability and the cross-sectional area inside the coil. The magnetic circuit length is proportional to the magnetic resistance length, and the cross-sectional area and magnetic permeability are inversely proportional to the magnetic resistance.

[0061] The magnetic resistance of the core at the current moment ,in is the cross-sectional area of ​​the core (ignoring the gap between the core and the coil, is the internal cross-sectional area of ​​the coil). Specifically: the vacuum permeability Relative magnetic permeability to the iron core and the cross-sectional area of ​​the core The product of is recorded as the first product, and the core at the current moment is inserted into the length The ratio of the first product is recorded as the magnetic resistance of the core at the current moment. .

[0062] The magnetic resistance of the air part at the current moment Specifically: Get the coil length Subtract the core insertion length at the current moment The difference is recorded as the length of the air part at the current moment, and the vacuum permeability is obtained. Cross-sectional area of ​​the core The product of the length of the air part at the current moment and the second product is recorded as the magnetic resistance of the air part at the current moment. .

[0063] Based on the two parts of magnetic resistance, the inductance is determined. The current magnetic circuit of the iron core part and the air part is a series magnetic circuit, so the total magnetic resistance of the entire inductor device is the sum of the magnetic resistance of the two parts. Specifically: the magnetic resistance of the iron core part at the current moment is The magnetic resistance of the air part at the current moment The sum of the values ​​is recorded as the total magnetic resistance of the inductor at the current moment. .

[0064] What needs to be explained is: the theoretical inductance of the inductor at the current moment ,in is the number of coil turns, a well-known calculation. The theoretical formula assumes that the magnetic flux generated by the coil entirely passes through the main magnetic circuit formed by the iron core and air. However, in reality, some of the magnetic flux bypasses the iron core and forms leakage flux through the air surrounding the coil, causing the actual inductance to be less than the theoretically calculated value. The deviation between the actual and theoretical inductance depends primarily on the leakage flux ratio. Therefore, for typical inductors, the leakage flux ratio remains unchanged, resulting in a largely unchanged effect on the inductance. However, in the aforementioned variable inductor, the leakage flux generated by the fixed coil remains unchanged. However, as the core insertion length changes, the total magnetic flux changes, causing the leakage flux ratio to change, and thus the effect of the leakage flux on the inductance to change. As the core insertion length increases, the magnetic path length of the core increases, and the total magnetic flux increases. However, since the size of both the coil and the core changes, the leakage flux remains unchanged, resulting in an increase in the leakage flux ratio. The increase in the leakage ratio directly depends on the change in insertion length, and the change in the leakage ratio is proportional to the insertion length ratio.

[0065] Due to the current ratio of the core insertion length , where the coil length Here it can be expressed as the total length of the magnetic circuit. And when the core is not inserted, that is, When the magnetic flux leakage ratio is the maximum magnetic flux leakage ratio , when the core is fully inserted, that is When the magnetic leakage ratio is the minimum magnetic leakage ratio .in, and It directly depends on the material and structure of the inductor itself. During the core insertion process, the insertion length ratio changes linearly, so the change of leakage magnetic ratio with insertion length can be regarded as arrive Therefore, the total range of magnetic leakage is , that is, the value of the leakage magnetic ratio reduction when the insertion is not complete. As the insertion length increases, the reduction in the leakage magnetic ratio at the current moment is , so the magnetic leakage ratio of the inductor device at the current moment is ,Thus, the magnetic leakage ratio of the inductor device can be determined based on different insertion lengths of the core.

[0066] Specifically: Get the core insertion length at the current moment Coil length The ratio of the core insertion length at the current moment is recorded as the ratio of the core insertion length to obtain the maximum magnetic leakage ratio. Subtract the minimum magnetic leakage ratio The difference is recorded as the total variation range of magnetic leakage, and the product of the ratio of the core insertion length at the current moment and the total variation range of magnetic leakage is obtained, which is recorded as the third product. The maximum magnetic leakage ratio The difference obtained by subtracting the third product is recorded as the magnetic leakage ratio of the inductor device at the current moment.

[0067] Step S003: Based on the current value at the current moment, the core temperature value output from the pre-constructed positive correlation function of the core temperature and current, the difference between the Curie temperature of the core and the reference temperature, combined with the vacuum permeability, the relative permeability of the core, and the proportion of the core insertion length in the coil length, determine the effective change in the core permeability of the inductor device at the current moment.

[0068] It should be noted that the aforementioned inductors are often connected to different circuits, so the current flowing through the coils is often inconsistent. This inconsistency can also affect the inductance of the inductor. Generally, current changes cause core temperature changes through energy loss, which in turn affects the core's magnetic properties, ultimately indirectly affecting the inductance. When current flows through the coil resistor, Joule losses are generated. The greater the current, the greater the copper loss, the more intense the coil heating. This heat is transferred through the insulation to the core, directly increasing the core temperature. Furthermore, current causes hysteresis and eddy current losses within the core. The greater the current, the greater the hysteresis and eddy current losses, and the more pronounced the core heating itself. Therefore, current and core heating are positively correlated. When the core temperature changes, the core's magnetic permeability changes. However, the temperature effect on the magnetic permeability of different core materials varies. In the aforementioned inductor, the core material is a high-permeability soft magnetic material (Permalloy). The magnetic permeability decreases slowly with increasing temperature, and the rate of change in magnetic permeability typically does not exceed 10%. The temperature range does not exceed the Curie temperature. Therefore, it is necessary to analyze the impact of different currents passing through the coil on the inductance of the inductor device.

[0069] Preferably, in one embodiment of the present invention, the method for obtaining the effective change in the magnetic permeability of the core of the inductor device at the current moment includes:

[0070] Known core reference temperature Under this condition, the magnetic permeability of the core is When current passes through the coil, it generates heat, and the current is positively correlated with the core's heat. Therefore, before monitoring, the core is fully inserted, the coil current is varied, and the core temperature is recorded. Therefore, when the core is fully inserted, the core temperature values ​​at different current values ​​are used to construct a positive correlation function between the core temperature and current using the least squares method. The independent variable in this function is the current value, and the dependent variable is the core temperature value.

[0071] It should be noted that the least square method is a well-known technology and the specific method will not be introduced here. Among them, the current variation range of the coil is ,in Indicates the rated current range of the inductor device, The disturbance current is preset and its value is set to 2. This example is used for description.

[0072] Therefore, in actual monitoring, the change in core temperature caused by the current at the current moment is ,in The current value of the inductor at the current moment is input into the core temperature value output from the positive correlation function of core temperature and current. The premise for the change of magnetic permeability caused by temperature change is that the temperature is less than the Curie temperature, so the temperature change amplitude that produces the change of magnetic permeability is , so the effective amplitude of temperature change at the current moment is ,in Indicates the Curie temperature of the iron core. The preset threshold coefficient is 10%, which is used as an example. The change in the magnetic permeability of the inductor core at the current moment is .

[0073] Specifically: Get the current value of the inductor at the current moment and input it into the core temperature value output from the positive correlation function of core temperature and current. , recorded as the target core temperature value, obtain the target core temperature value minus the core reference temperature The difference is recorded as the change in core temperature caused by the current at the current moment , get the Curie temperature of the iron core Subtract the core's base temperature The difference is recorded as the temperature change amplitude that causes the change in magnetic permeability, and the change in core temperature caused by the current at the current moment is recorded as the temperature change amplitude that causes the change in magnetic permeability. The ratio of the temperature change amplitude that produces the change in magnetic permeability is recorded as the effective amplitude of the temperature change at the current moment. , with vacuum permeability Relative magnetic permeability to the iron core The product of the preset threshold coefficient is recorded as the magnetic permeability threshold, and the magnetic permeability threshold is calculated by multiplying the effective amplitude of the temperature change at the current moment. The product of is recorded as the change in the magnetic permeability of the inductor core at the current moment. .

[0074] It should be noted that: similarly, in the above-mentioned variable inductance device, as the insertion length of the iron core changes, the proportion of the iron core inside the coil changes, and the temperature change of the iron core caused by the current mainly passes through the iron core inside the coil, so the insertion length of the iron core directly affects the temperature change of the iron core, and thus affects the change of the magnetic permeability of the iron core.

[0075] Therefore, the effective heating length of the iron core passing through the coil is the proportion of the iron core insertion length at the current moment. , so the effective change in the magnetic permeability of the inductor core at the current moment is .

[0076] Specifically: the proportion of the core insertion length at the current moment The change in the magnetic permeability of the inductor core at the current moment The product of is recorded as the effective change in the magnetic permeability of the inductor core at the current moment. .

[0077] Step S004: Determine the effective total magnetic resistance of the electromagnetic device at the current moment based on the vacuum magnetic permeability, the coil length, the relative magnetic permeability and cross-sectional area of ​​the iron core, and the iron core insertion length at the current moment, in combination with the effective change; determine the true effective inductance of the inductor device at the current moment based on the effective total magnetic resistance and the number of coil turns, in combination with the magnetic leakage ratio of the inductor device at the current moment.

[0078] What needs to be explained is: the theoretical inductance of the inductor at the current moment At this point, the heating of the core caused by the current changes the core's magnetic permeability, which in turn changes the total magnetic resistance of the inductor, and thus changes the inductance of the inductor. At this point, the total magnetic resistance of the inductor needs to be recalculated based on the effective change in the core's magnetic permeability.

[0079] Preferably, in one embodiment of the present invention, the method for obtaining the real effective inductance of the inductor device at the current moment includes:

[0080] First, based on the effective change in the magnetic permeability of the core, the effective magnetic permeability of the core at the current moment is determined to be Then, determine the effective total magnetic resistance of the electromagnetic device at the current moment ,in is the magnetic resistance of the air at the current moment , is the effective magnetic resistance of the core part at the current moment. Further, based on the current value of the inductor device at the current moment, the core insertion length at the current moment is determined to be The effective inductance of the inductor at the current moment is Furthermore, the above analysis obtains the magnetic leakage ratio of the inductor device at the current moment Therefore, based on the magnetic leakage ratio, the effective inductance of the inductor is corrected to obtain the real effective inductance of the inductor at the current moment. .

[0081] Specifically: Get vacuum permeability Relative magnetic permeability to the iron core The product of minus the effective change in the magnetic permeability of the inductor core at the current moment The difference between the two values ​​is used as the effective magnetic permeability of the core at the current moment, and the effective magnetic permeability and cross-sectional area of ​​the core at the current moment are obtained. The product of is recorded as the fourth product, and the core at the current moment is inserted into the length The ratio of the fourth product is recorded as the effective magnetic resistance of the core part at the current moment, and the effective magnetic resistance of the core part at the current moment is divided by the magnetic resistance of the air part at the current moment. The sum of the effective total magnetic resistance of the electromagnetic device at the current moment , the number of coil turns squared The effective total magnetic resistance of the electromagnetic device at the current moment The ratio of is recorded as the effective inductance of the inductor at the current moment. , the inverse proportional value of the magnetic leakage ratio of the inductor device at the current moment The effective inductance of the inductor at the current moment The product of is recorded as the real effective inductance of the inductor at the current moment. .

[0082] It should be noted that in the above ratio calculation, if the denominator is 0, then the denominator is set to 1 to ensure that the ratio calculation is valid. This example is used for description.

[0083] The present invention also provides an online monitoring system for the inductance of an inductor device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program stored in the memory to implement the steps of the aforementioned method for online monitoring the inductance of an inductor device.

[0084] So far, the present invention is completed.

[0085] In summary, in an embodiment of the present invention, the magnetic leakage ratio of the inductor at the current moment is determined based on the proportion of the core insertion length in the coil length at the current moment, combined with the minimum and maximum magnetic leakage ratios. The core temperature value output from the pre-constructed positive correlation function of the core temperature and current is input according to the current value at the current moment, the difference between the Curie temperature of the core and the reference temperature, combined with the vacuum magnetic permeability, the relative magnetic permeability of the core, and the proportion of the core insertion length in the coil length, to determine the effective change in the magnetic permeability of the core of the inductor at the current moment. The effective total magnetic resistance of the electromagnetic device at the current moment is determined based on the vacuum magnetic permeability, the coil length, the relative magnetic permeability and cross-sectional area of ​​the core, and the core insertion length at the current moment, combined with the effective change. The true effective inductance of the inductor at the current moment is determined based on the effective total magnetic resistance and the number of coil turns, combined with the magnetic leakage ratio of the inductor at the current moment. The present invention improves the accuracy of online monitoring of the inductance of the inductor.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for online monitoring of inductance of an inductor device, characterized in that: The method comprises the following steps: Obtain vacuum magnetic permeability, minimum and maximum magnetic leakage ratios of inductors, coil length, number of coil turns, relative magnetic permeability of the core, cross-sectional area of ​​the core, Curie temperature of the core, base temperature of the core, and the current core insertion length and current value; Determining the magnetic leakage ratio of the inductor at a current moment includes: obtaining a ratio of the core insertion length to the coil length at a current moment, recording the ratio as the core insertion length ratio at a current moment; obtaining a difference between a maximum magnetic leakage ratio and a minimum magnetic leakage ratio, recording the ratio as a total magnetic leakage variation range; obtaining a product of the core insertion length ratio and the total magnetic leakage variation range at a current moment, recording the product as a third product, and subtracting the difference between the maximum magnetic leakage ratio and the third product as the magnetic leakage ratio of the inductor at a current moment; Determining an effective change in the magnetic permeability of the core of the inductor device at a current moment, including: obtaining a current value of the inductor device at a current moment, inputting the current value into a core temperature value output by a positive correlation function between the core temperature and the current, recording the value as a target core temperature value; determining an effective amplitude of the temperature change at a current moment based on the target core temperature value, a reference temperature of the core, and a Curie temperature of the core; and determining an amount of change in the magnetic permeability of the core of the inductor device at a current moment based on the relative magnetic permeability of the vacuum and the core and the effective amplitude of the temperature change at a current moment; The product of the ratio of the core insertion length at the current moment and the change in the magnetic permeability of the inductor core at the current moment is recorded as the effective change in the magnetic permeability of the inductor core at the current moment; The determining, based on the vacuum magnetic permeability, the relative magnetic permeability of the core, and the effective amplitude of the temperature change at the current moment, of the change in magnetic permeability of the core of the inductor device at the current moment includes: multiplying the product of the vacuum magnetic permeability, the relative magnetic permeability of the core, and a preset threshold coefficient as the magnetic permeability threshold; and multiplying the product of the magnetic permeability threshold and the effective amplitude of the temperature change at the current moment as the change in magnetic permeability of the core of the inductor device at the current moment; Determining the effective total magnetic resistance of the electromagnetic device at a current moment includes: determining the magnetic resistance of the air portion at a current moment based on the vacuum magnetic permeability, the cross-sectional area of ​​the iron core, the coil length, and the iron core insertion length at a current moment; determining the effective magnetic resistance of the iron core portion at a current moment based on the vacuum magnetic permeability, the relative magnetic permeability of the iron core, the cross-sectional area of ​​the iron core, the iron core insertion length at a current moment, and the effective change in the magnetic permeability of the iron core of the inductor device at a current moment; recording the sum of the effective magnetic resistance of the iron core portion at a current moment and the magnetic resistance of the air portion at a current moment as the effective total magnetic resistance of the electromagnetic device at a current moment; Determining the true effective inductance of the inductor device at the current moment includes: recording the ratio of the square of the number of coil turns to the effective total magnetic resistance of the electromagnetic device at the current moment as the effective inductance of the inductor device at the current moment; and recording the product of the inverse proportional value of the magnetic leakage ratio of the inductor device at the current moment and the effective inductance of the inductor device at the current moment as the true effective inductance of the inductor device at the current moment.

2. The method for online monitoring of inductance of an inductor device according to claim 1, characterized in that: The specific steps of determining the effective amplitude of the temperature change at the current moment based on the target core temperature value, the core reference temperature, and the core Curie temperature are as follows: Obtain the difference between the target core temperature and the core reference temperature, and record it as the change in core temperature caused by the current at the current moment; Obtain the difference between the Curie temperature of the core and the base temperature of the core, and record it as the temperature change amplitude that produces the change in magnetic permeability; The ratio of the change in core temperature caused by the current at the current moment to the temperature change amplitude that produces the change in magnetic permeability is recorded as the effective amplitude of the temperature change at the current moment.

3. The method for online monitoring of inductance of an inductor device according to claim 1, characterized in that: The specific steps of determining the magnetic resistance of the air portion at the current moment based on the vacuum magnetic permeability, the cross-sectional area of ​​the iron core, the coil length, and the iron core insertion length at the current moment are as follows: Obtain the difference between the coil length and the core insertion length at the current moment, and record it as the length of the air portion at the current moment; The product of the vacuum magnetic permeability and the cross-sectional area of ​​the iron core is obtained and recorded as the second product. The ratio of the length of the air portion at the current moment to the second product is recorded as the magnetic resistance of the air portion at the current moment.

4. The method for online monitoring of inductance of an inductor device according to claim 1, characterized in that: The method of determining the effective magnetic resistance of the core portion at the current moment based on the vacuum magnetic permeability, the relative magnetic permeability of the core, the cross-sectional area of ​​the core, the core insertion length at the current moment, and the effective change in the magnetic permeability of the core of the inductor at the current moment comprises the following specific steps: Obtain the difference between the product of the vacuum magnetic permeability and the relative magnetic permeability of the iron core and the effective change in the magnetic permeability of the iron core of the inductor device at the current moment as the effective magnetic permeability of the iron core at the current moment; The product of the effective magnetic permeability of the iron core at the current moment and the cross-sectional area of ​​the iron core is obtained, which is recorded as the fourth product. The ratio of the iron core insertion length at the current moment to the fourth product is recorded as the effective magnetic resistance of the iron core part at the current moment.

5. An online monitoring system for the inductance of an inductor device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is executed by a processor, the steps of the method for online monitoring of the inductance of an inductor device according to any one of claims 1 to 4 are implemented.

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