Inductance testing device based on LC resonance principle
By adopting a test method based on the LC resonance principle in the inductance testing device, the problem of inaccurate measurement of inductance values at different frequencies is solved, and higher measurement accuracy and lower production costs are achieved.
Patent Information
- Application Number
- CN202411978533.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-28
- Publication Date
- 2025-03-14
AI Technical Summary
Due to the influence of parasitic parameters, existing inductance testing instruments have a large difference in inductance values at different test frequencies, resulting in low measurement accuracy and large equipment size and high price.
An inductance testing device based on the LC resonance principle is adopted, and a built-in test system is formed through an independently controlled charging circuit and an LC resonance circuit. The LC resonance principle is used to perform inductance measurement to reduce the dependence on parasitic parameters.
It improves the accuracy of inductance measurement, makes the inductance testing device affordable and small in size, suitable for large-scale equipment, and reduces the production and R&D costs of enterprises.
Smart Images
Figure CN119619634A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of inductance testing equipment, and in particular relates to an inductance testing device based on the LC resonance principle. Background Art
[0002] LRC tester is an instrument used to measure the corresponding physical parameters of capacitance, resistance and inductance components. Compared with the commonly used multimeter, LRC tester not only has higher measurement accuracy, but also can measure multiple parameters of components, such as impedance, quality factor, etc.
[0003] At present, the inductance test instruments on the market are usually LRC test equipment, which usually applies a standard AC voltage to the object under test, then collects the current amplitude and phase, and then measures the inductance through the impedance meter method. Although this method is easy to operate, it is bulky and expensive, and its accuracy is affected by parasitic parameters. In actual work, the phenomenon shown is that the inductance value varies greatly at different test frequencies. Summary of the invention
[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0005] An inductance testing device based on the LC resonance principle, comprising:
[0006] Each of them contains a charging circuit and an LC resonant circuit composed of a capacitor C1 and independently controlled, and the charging circuit and the LC resonant circuit form a built-in test system for the external inductor L2;
[0007] The end to be tested has an interface electrically connected to the LC resonant circuit and a parasitic capacitor C2 connected in parallel with the inductor L2.
[0008] Furthermore, the charging circuit includes a resistor R1 connected in series with the capacitor C1, a power source V1, and a switch S1 for controlling on and off.
[0009] Furthermore, the LC resonant circuit includes an inductor L1 connected in series with the capacitor C1 and a switch S2 for controlling on and off.
[0010] Further, after the switch S1 is closed and the switch S2 is opened, the power supply V1, the switch S1, the resistor R1, and the capacitor C1 form the charging circuit, and after the switch S2 is closed and the switch S1 is opened, the capacitor C1, the inductor L1, the inductor L2, and the switch S2 form the LC resonant circuit.
[0011] Furthermore, the capacity of the capacitor C1 is greater than the capacity of the capacitor C2.
[0012] Furthermore, the capacitor C1 includes any one of a CBB capacitor, an NPO capacitor, and a COG capacitor.
[0013] Furthermore, the inductor L1 includes an air-core coil inductor.
[0014] Furthermore, a magnetic field shielding box is arranged outside the built-in test system.
[0015] Compared with the prior art, the present invention has the following beneficial effects:
[0016] The present invention changes the inductance testing method with a circuit, uses the LC resonance principle to measure the inductance, is insensitive to parasitic parameters, and has a more accurate measurement result, so that the inductance testing device using the circuit is affordable and compact, can be equipped in large quantities, and can effectively reduce the production and research and development costs of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic diagram of the structure of a test circuit according to an embodiment of the present invention;
[0018] Figure 2 Schematic diagram of a test waveform according to an embodiment of the present invention. DETAILED DESCRIPTION
[0019] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0020] Among them, the drawings are only used for illustrative purposes, and they only show schematic diagrams rather than actual drawings, and cannot be understood as limitations on this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted, and the same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer" and the like appear, the directions or positional relationships indicated are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, so the terms describing the positional relationship in the drawings are only used for illustrative purposes, and cannot be understood as limitations on this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.
[0021] like Figure 1 - Figure 2 As shown, an inductance testing device based on the LC resonance principle of the present invention comprises:
[0022] Both contain a charging circuit and an LC resonant circuit composed of a capacitor C1 and independently controlled, and the charging circuit and the LC resonant circuit form a built-in test system for the external inductor L2;
[0023] The end to be tested has an interface electrically connected to the LC resonant circuit and a parasitic capacitor C2 connected in parallel with the inductor L2.
[0024] The present invention changes the inductance test method with a circuit and uses the LC resonance principle to measure the inductance, thereby solving the problem that the inductance value cannot be correctly measured due to the influence of the inductance parasitic parameters, so that the inductance test device using the circuit is affordable and compact.
[0025] like Figure 1 As shown, the above interfaces are divided into interface 1 and interface 2, both of which are external. They are responsible for the inductance L2 that needs to be measured externally. The switch S1 controls the resistor R1 and the capacitor C1 to be connected in series, and the switch S2 controls the inductance L1 and the capacitor C1 to be connected in series.
[0026] Among them, inductor L2 is the external inductor that needs to be measured.
[0027] Specifically, the charging circuit includes a resistor R1 connected in series with a capacitor C1, a power source V1, and a switch S1 for controlling on and off.
[0028] The LC resonant circuit includes an inductor L1 connected in series with a capacitor C1 and a switch S2 for controlling on and off.
[0029] Specifically, when the switch S1 is closed and the switch S2 is opened, the power supply V1, the switch S1, the resistor R1, and the capacitor C1 form a charging circuit. When the switch S2 is closed and the switch S1 is opened, the capacitor C1, the inductor L1, the inductor L2, and the switch S2 form an LC resonant circuit.
[0030] When the device is used, the switch S2 is first opened and the switch S1 is closed, and the power source V1 charges the capacitor C1.
[0031] After charging is completed, switch S1 is opened and switch S2 is closed. At this time, if interface 1 and interface 2 are connected to the external inductor L2 to be tested, the following will be obtained in the test system: Figure 2 The waveform shown.
[0032] Based on the measured period T, the frequency is obtained Capacitance C1 and 2π are known quantities. Since capacitance C1 is much larger than capacitance C2, the formula The inductance of the inductor L can be directly calculated.
[0033] Since the inductor L at this time is inductor L1 and inductor L2 connected in series, it is also necessary to subtract the inductance of inductor L1 to obtain the inductance of inductor L2. This step is completed during the debugging process. The screen in this device only displays the inductance of inductor L2.
[0034] Among them, the inductor L1 is used as a basic component to make the circuit oscillate, and the resistor R1 plays a role of current limiting when charging the inductor C1.
[0035] In addition, to ensure the accuracy of the measurement results, the capacitance of capacitor C1 should be much larger than that of capacitor C2 to reduce the influence of parasitic capacitance C2 on resonance. It should also be coordinated with inductor L1 so that the measurement circuit can operate within a more appropriate frequency range.
[0036] Capacitor C1 should be a non-polar capacitor with high stability as much as possible. For example, capacitor C1 can be a capacitor made of materials such as CBB capacitor, NPO capacitor, COG capacitor or mica.
[0037] In addition, the inductor L1 should be selected as an inductor with high stability and small parasitic parameters, such as an air-core coil inductor.
[0038] In order to ensure the normal operation of the entire circuit, a certain external magnetic field shielding should be required, and a shielding box should be set outside the built-in test system.
[0039] The above-mentioned shielding box can use existing technology and is easy to implement. It does not belong to the protection scope of this application. Therefore, it at least has the beneficial effects brought by the technical solution of the above-mentioned embodiment, which will not be repeated here.
[0040] The above are only embodiments of the present invention. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. An inductance testing device based on the LC resonance principle, characterized in that: include: Each of them contains a charging circuit and an LC resonant circuit composed of a capacitor C1 and independently controlled, and the charging circuit and the LC resonant circuit form a built-in test system for the external inductor L2; The end to be tested has an interface electrically connected to the LC resonant circuit and a parasitic capacitor C2 connected in parallel with the inductor L2.
2. The inductance testing device based on the LC resonance principle as claimed in claim 1, characterized in that: The charging circuit includes a resistor R1 connected in series with a capacitor C1, a power source V1, and a switch S1 for controlling on and off.
3. The inductance testing device based on the LC resonance principle as claimed in claim 2, characterized in that: The LC resonant circuit includes an inductor L1 connected in series with a capacitor C1 and a switch S2 for controlling on and off.
4. The inductance testing device based on the LC resonance principle as claimed in claim 3, characterized in that: When the switch S1 is closed and the switch S2 is opened, the power supply V1, the switch S1, the resistor R1, and the capacitor C1 form a charging circuit. When the switch S2 is closed and the switch S1 is opened, the capacitor C1, the inductor L1, the inductor L2, and the switch S2 form the LC resonant circuit.
5. The inductance testing device based on the LC resonance principle as claimed in claim 1, characterized in that: The capacity of the capacitor C1 is greater than the capacity of the capacitor C2.
6. The inductance testing device based on the LC resonance principle as claimed in claim 1, characterized in that: The capacitor C1 includes any one of a CBB capacitor, an NPO capacitor, and a COG capacitor.
7. The inductance testing device based on the LC resonance principle as claimed in claim 1, characterized in that: The inductor L1 includes an air-core coil inductor.
8. The inductance testing device based on the LC resonance principle as claimed in claim 1, characterized in that: A shielding box is arranged outside the built-in test system.