High-frequency inductor saturation current testing device

Abstract

The utility model discloses a high-frequency inductor saturation current testing device, which comprises a direct current voltage source with adjustable voltage; the charging switch is connected in series with the direct-current voltage source and the high-frequency inductor to be tested so as to form a charging loop; the pulse signal generation unit is coupled with the charging switch; the discharging loop comprises a high-frequency inductor and is used for providing a follow current loop for the high-frequency inductor under the condition that the charging loop is disconnected; the current testing unit is connected in series with the high-frequency inductor and is used for detecting the real-time current of the high-frequency inductor; the voltage testing unit is connected in parallel with the high-frequency inductor and is used for detecting the real-time voltage of the high-frequency inductor; and the display unit is used for displaying the change conditions of the real-time current and the real-time voltage of the high-frequency inductor. According to the utility model, the test can be carried out under the condition of lower actual cost, the saturation current value of the high-frequency inductor can be obtained only by observing the change conditions of the real-time current and the real-time voltage, the test is more convenient, and the reliability is high.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic measurement, in particular to a high-frequency inductance saturation current testing device. Background Art

[0002] Currently, in the prior art, an LCR tester and a DC bias current source are usually combined to test the saturation current of an inductor. The DC bias current source provides a bias current at a specific current, and the LCR tester measures the inductance under the bias condition. By adjusting the bias current, the change of the inductance is measured to determine the saturation current. This method is relatively expensive and has high requirements for equipment. Considering that the DC bias current belongs to a precision power supply, its accuracy will ultimately affect the accuracy of the measured saturation current. And during measurement, the measured inductor coil needs to be connected to both the DC bias current source and the LCR tester simultaneously. It is necessary to protect the LCR tester from the influence of DC and prevent the measurement AC signal of the LCR tester from being coupled to the coil. Content of the Utility Model

[0003] The utility model aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the utility model provides a high-frequency inductance saturation current testing device with low cost, high reliability and convenient testing.

[0004] In a first aspect, an embodiment of the utility model provides a high-frequency inductance saturation current testing device, including:

[0005] A DC voltage source with adjustable voltage;

[0006] A charging switch, which is serially connected to the DC voltage source and the high-frequency inductor to be tested to form a charging circuit;

[0007] A pulse signal generating unit, which is coupled to the charging switch and is used to provide a single pulse signal to control the on or off of the charging switch;

[0008] A discharging circuit, including the high-frequency inductor, and is used to provide a freewheeling circuit for the high-frequency inductor when the charging circuit is disconnected;

[0009] A current testing unit, which is serially connected to the high-frequency inductor and is used to detect the real-time current of the high-frequency inductor;

[0010] A voltage testing unit, which is paralleled to the high-frequency inductor and is used to detect the real-time voltage of the high-frequency inductor;

[0011] A display unit, which is respectively connected to the output end of the current testing unit and the output end of the voltage testing unit, and is used to display the change of the real-time current and real-time voltage of the high-frequency inductor.

[0012] Optionally, in an embodiment of the present utility model, the discharge circuit further includes a first discharge switch, and the first discharge switch is connected in parallel with the high-frequency inductor to form the discharge circuit.

[0013] Optionally, in an embodiment of the present utility model, the discharge circuit further includes a second discharge switch and a third discharge switch, and the DC voltage source, the second discharge switch, the high-frequency inductor, and the third discharge switch are connected in series to form the discharge circuit.

[0014] Optionally, in an embodiment of the present utility model, the charging circuit further includes a circuit protection element for providing charging protection for the high-frequency inductor, and the circuit protection element is connected in series with the charging switch, the DC voltage source, and the high-frequency inductor to form the charging circuit.

[0015] Optionally, in an embodiment of the present utility model, the discharge circuit further includes a discharge resistor for consuming the stored energy in the high-frequency inductor, and the discharge resistor and the first discharge switch are connected in series to form a discharge branch, and the discharge branch is connected in parallel with the high-frequency inductor to form the discharge circuit.

[0016] Optionally, in an embodiment of the present utility model, the preset ideal signal width of the pulse signal generating unit satisfies the following conditions:

[0017] S = (1.5 * a * L0) / V;

[0018] where S is the preset ideal signal width of the pulse signal generating unit, a is the saturation current value of the high-frequency inductor, L0 is the initial inductance of the high-frequency inductor, and V is the voltage value of the DC voltage source.

[0019] Optionally, in an embodiment of the present utility model, the charging switch employs a MOSFET or an IGBT.

[0020] Optionally, in an embodiment of the present utility model, the display unit uses an oscilloscope.

[0021] The high-frequency inductor saturation current testing device proposed by the present utility model can perform charging tests on the high-frequency inductor to be tested through a DC voltage source with adjustable voltage and a formed charging circuit, combined with a pulse signal generating unit to control the conduction or cutoff of the charging switch. During this process, the real-time current and real-time voltage of the high-frequency inductor are detected by the current testing unit and the voltage testing unit. Compared with the related prior art, there is no need to use precision power supplies and precision testing equipment, and the testing can be carried out at a lower actual cost. Moreover, the display unit clearly shows the changes in the real-time current and real-time voltage of the high-frequency inductor. Without complex calculations, the saturation current value of the high-frequency inductor can be obtained simply by observing the changes in the real-time current and real-time voltage. Therefore, the testing is more convenient and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. is the circuit schematic diagram of the high-frequency inductor saturation current testing device provided by an embodiment of the present utility model;

[0023] Figure 2 FIG. is the circuit schematic diagram of the high-frequency inductor saturation current testing device provided by another embodiment of the present utility model;

[0024] Figure 3 FIG. is a timing waveform diagram when the high-frequency inductor saturation current testing device provided by an embodiment of the present utility model is working;

[0025] Figure 4 FIG. is the circuit schematic diagram of the high-frequency inductor saturation current testing device provided by another embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0027] The present utility model provides a high-frequency inductor saturation current testing device, comprising: a DC voltage source with adjustable voltage; a charging switch, which is serially connected to the DC voltage source and the high-frequency inductor to be tested to form a charging loop; a pulse signal generating unit, which is coupled to the charging switch and used to provide a single-pulse signal to control the conduction or cut-off of the charging switch; a discharging loop, which includes the high-frequency inductor and is used to provide a freewheeling loop for the high-frequency inductor when the charging loop is disconnected; a current testing unit, which is serially connected to the high-frequency inductor and used to detect the real-time current of the high-frequency inductor; a voltage testing unit, which is parallely connected to the high-frequency inductor and used to detect the real-time voltage of the high-frequency inductor; and a display unit, which is respectively connected to the output ends of the current testing unit and the voltage testing unit and used to display the change conditions of the real-time current and real-time voltage of the high-frequency inductor. In the present utility model, through the DC voltage source with adjustable voltage and the formed charging loop, combined with the pulse signal generating unit to control the conduction or cut-off of the charging switch, the charging test of the high-frequency inductor to be tested can be carried out. In this process, the real-time current and real-time voltage of the high-frequency inductor are detected by the current testing unit and the voltage testing unit. Compared with the related prior art, there is no need to adopt precision power supplies and precision testing equipment, and the test can be carried out with lower actual costs. Moreover, the change conditions of the real-time current and real-time voltage of the high-frequency inductor are clearly displayed by the display unit. Without complex calculations, the saturation current value of the high-frequency inductor can be obtained only by observing the change conditions of the real-time current and real-time voltage. Therefore, the test is more convenient and has high reliability.

[0028] Figure 1 It is the circuit schematic diagram of the high-frequency inductor saturation current testing device provided by an embodiment of the present utility model.

[0029] As Figure 1 shown, the high-frequency inductor saturation current testing device specifically includes but is not limited to:

[0030] A DC voltage source DC with adjustable voltage, that is, the voltage of the DC voltage source DC can be selected and set according to the actual application scenario, and the specific range of voltage adjustment can be set by itself, which is not limited here;

[0031] A charging switch S1, which is serially connected to the DC voltage source DC and the high-frequency inductor L to be tested to form a charging loop 100. Among them, the charging switch S1 can but is not limited to adopt a fully controlled power electronic switch device, such as a MOSFET or an IGBT;

[0032] A pulse signal generating unit G, which is coupled to the charging switch S1 and used to provide a single-pulse signal to control the conduction or cut-off of the charging switch S1;

[0033] A discharging loop 200, which includes the high-frequency inductor L and is used to provide a freewheeling loop for the high-frequency inductor L when the charging loop 100 is disconnected;

[0034] The current test unit A1, which is connected in series with the high-frequency inductor L, is used to detect the real-time current of the high-frequency inductor L. In this embodiment, an ammeter as shown in Figure 1 can be but is not limited to being used;

[0035] The voltage test unit V1, which is connected in parallel with the high-frequency inductor L, is used to detect the real-time voltage of the high-frequency inductor L. In this embodiment, a voltmeter as shown in Figure 1 can be but is not limited to being used;

[0036] The display unit Y, which is respectively connected to the output end of the current test unit A1 and the output end of the voltage test unit V1, is used to display the change conditions of the real-time current and real-time voltage of the high-frequency inductor L. The display unit Y can be but is not limited to using an oscilloscope.

[0037] It can be seen that through the DC voltage source DC with adjustable voltage and the formed charging circuit 100, combined with the pulse signal generating unit G to control the conduction or cut-off of the charging switch S1, the charging test of the to-be-tested high-frequency inductor L can be carried out. In this process, the real-time current and real-time voltage of the high-frequency inductor L are detected through the current test unit A1 and the voltage test unit V1. Compared with the related prior art, there is no need to use precision power supplies and precision test equipment, and the test can be carried out with lower actual costs. Moreover, the change conditions of the real-time current and real-time voltage of the high-frequency inductor L are clearly displayed through the display unit Y. Without complex calculations, the saturation current value of the high-frequency inductor L can be obtained only by observing the change conditions of the real-time current and real-time voltage. Therefore, the test is more convenient and has high reliability.

[0038] In one embodiment, as shown in Figure 1 , the discharge circuit 200 can also but is not limited to include a first discharge switch D1. The first discharge switch D1 is connected in parallel with the high-frequency inductor L to form the discharge circuit 200. The discharge circuit 200 can provide a freewheeling circuit for the high-frequency inductor L when the charging circuit 100 is disconnected. That is to say, even if the charging circuit 100 is turned off, there is still current in the high-frequency inductor L and it stores energy. Therefore, the first discharge switch D1 can be automatically opened at this time to provide a freewheeling circuit for the high-frequency inductor L, so that the circuit returns to the initial state of zero, waiting to be applied for the next charging test.

[0039] In one embodiment, as shown in Figure 2As shown, the discharge circuit 200 may further include, but is not limited to, a discharge resistor R1 for consuming the stored energy in the high-frequency inductor L. The discharge resistor R1 and the first discharge switch D1 are connected in series to form a discharge branch, and the discharge branch is connected in parallel with the high-frequency inductor L to form the discharge circuit 200. Specifically, by setting the discharge resistor R1 in the discharge circuit 200, the stored energy in the high-frequency inductor L can be quickly consumed, avoiding the problem of too slow discharge speed caused by using the first discharge switch D1 for discharge. If the discharge speed is too slow, the high-frequency inductor L will be in a large current state for a long time, which is likely to cause damage to the high-frequency inductor L.

[0040] To better clarify the working principles of the above embodiments, the following is based on Figure 1 the high-frequency inductor saturation current test device shown in Figure 3 and a timing waveform diagram during the operation of the high-frequency inductor saturation current test device shown in Figure 3 for illustration. Among them,

[0041] Referring to Figure 1 and Figure 3 , the operation starts at time T1. The pulse signal generating unit G emits a single pulse signal with a certain width and acts on the charging switch S1, causing the charging switch S1 to conduct. The DC voltage source DC, the charging switch S1, and the high-frequency inductor L form a charging circuit 100. The voltage of the DC voltage source DC directly acts on both ends of the high-frequency inductor L, and the high-frequency inductor L is charged, and the current rises linearly. The current testing unit A1 and the voltage testing unit V1 respectively collect the current and voltage waveforms of the high-frequency inductor L. At this time, the voltage is the voltage of the DC voltage source DC, and the current is the charging current of the high-frequency inductor L.

[0042] At time T2, since the voltage of the DC voltage source DC continues to be applied across the high-frequency inductor L, the current of the high-frequency inductor L continues to increase, and the magnetization intensity in the magnetic core continues to rise. Until the maximum magnetization intensity of the magnetic core is reached, the current can no longer increase, and the high-frequency inductor L begins to exhibit a saturation state, and the inductance drops sharply. Since the voltage applied across the high-frequency inductor L remains unchanged and the inductance drops, the current increases further sharply. At the same time, due to the drop in inductance and inductive reactance, almost all of the voltage of the original DC voltage source DC is applied across the high-frequency inductor L. At this time, the high-frequency inductor L and the charging switch S1 divide the voltage, and the voltage across the high-frequency inductor L drops, and the voltage across the charging switch S1 gradually rises.

[0043] At time T3, the current in the charging circuit 100 further rises. When the current reaches the saturation conduction depth of the charging switch S1, the voltage across the charging switch S1 begins to rise and enters the desaturation state. The voltage across the high-frequency inductor L rapidly drops. At this time, the current in the charging circuit 100 depends on the saturation conduction depth of the charging switch S1.

[0044] At time T4, the pulse signal generating unit G promptly returns to the low level, turning off the charging switch S1 and disconnecting the charging circuit 100. At this time, although the charging circuit 100 is turned off, there is still current in the high-frequency inductor L, storing energy. Therefore, the first discharge switch D1 can be automatically turned on at this time to provide a freewheeling circuit for the high-frequency inductor L, restoring the circuit to the initial zero state.

[0045] Through the above description of the working principle combined with Figure 3 It can be seen that at time T2, the high-frequency inductor L begins to enter the saturation state, and the voltage waveform across the high-frequency inductor L significantly shows a downward trend. Therefore, find the moment when the real-time voltage collected by the voltage test unit V1 on the oscilloscope significantly shows a downward trend. The real-time current collected by the current test unit A1 corresponding to this moment can be considered as the saturation current of the high-frequency inductor L, thereby obtaining the saturation current value of the high-frequency inductor L.

[0046] It can be seen that the width of the single pulse signal affects the measurement result. If the width of the single pulse signal is too narrow, the charging switch S1 will be turned off before the high-frequency inductor L reaches the saturation current, resulting in a test failure. If the width of the single pulse signal is too wide, after the high-frequency inductor L reaches the saturation current, the charging switch S1 is in the desaturation conduction state for a long time, which may cause the charging switch S1 to overheat and fail. Therefore, it is necessary to reasonably set the width of the single pulse signal. Specifically, the signal width of the pulse signal generating unit G can be set and is set according to the following method. The preset ideal signal width of the pulse signal generating unit G satisfies the following conditions:

[0047] S = (1.5 * a * L0) / V;

[0048] Where S is the preset ideal signal width of the pulse signal generating unit G, a is the saturation current value of the high-frequency inductor L, L0 is the initial inductance of the high-frequency inductor L, and V is the voltage value of the DC voltage source DC.

[0049] It should be noted that the amplitude of the pulse signal generating unit G can be set to a preset value, so as to set the saturation conduction depth of the charging switch S1, limit the maximum current after the high-frequency inductor L is saturated, and ensure that the current of the high-frequency inductor L does not exceed the limit current. For example, at time T3, when the current of the charging loop 100 reaches the saturation conduction depth of the charging switch S1, since different amplitudes of the pulse signal generating unit G correspond to different saturation conduction depths, the saturation conduction depth of the charging switch S1 can be correspondingly set by setting the amplitude of the pulse signal generating unit G; in addition, the rising edge of the output signal of the pulse signal generating unit G can be used as the waveform trigger condition of the oscilloscope, that is, when a single pulse signal appears at the rising edge, the oscilloscope starts to store data according to the preset sampling depth and displays the waveform on the screen. In this way, the effective waveform can be stored to the maximum extent, avoiding waveform distortion, and thus improving the validity of the test data.

[0050] In one embodiment, as Figure 4 shown, the discharge loop 200 further includes a second discharge switch D2 and a third discharge switch D3. The DC voltage source DC, the second discharge switch D2, the high-frequency inductor L, and the third discharge switch D3 are connected in series to form the discharge loop 200. That is to say, when the charging loop 100 is turned off, the voltage of the DC voltage source DC is applied reversely across the two ends of the high-frequency inductor L, and the current of the high-frequency inductor L drops rapidly. At this time, the second discharge switch D2 and the third discharge switch D3 are used for discharge limitation to avoid long-term continuous current of the energy storage of the high-frequency inductor L and prevent damage to the high-frequency inductor L. Among them, the specifications and parameters of the second discharge switch D2 and the third discharge switch D3 can be set correspondingly according to the actual application scenario. For example, it can be, but is not limited to, a rectifier diode, a zener diode, etc., and there is no limitation here.

[0051] In one embodiment, as Figure 4 shown, the charging loop 100 further includes a loop protection element M for providing charging protection for the high-frequency inductor L. The loop protection element M is connected in series with the charging switch S1, the DC voltage source DC, and the high-frequency inductor L to form the charging loop 100. Among them, the specifications and parameters of the loop protection element M can be set correspondingly according to the actual application scenario. For example, it can be, but is not limited to, a ceramic gas discharge tube, a semiconductor discharge tube, a TVS diode, and a varistor, etc., and there is no limitation here.

[0052] It should be noted that the high-frequency inductor saturation current testing device and application scenarios described in the embodiments of the present utility model are for more clearly explaining the technical solutions of the embodiments of the present utility model, and do not constitute a limitation to the technical solutions provided by the embodiments of the present utility model. As known to those skilled in the art, with the evolution of the high-frequency inductor saturation current testing device and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present utility model are equally applicable to similar technical problems.

[0053] The above-described embodiments are only used to illustrate the technical solutions of the present utility model, rather than to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present utility model, and should all be included within the protection scope of the present utility model.

Claims

1. A high-frequency inductor saturation current testing device, characterized in that, Comprising: A DC voltage source with adjustable voltage; A charging switch, serially connected to the DC voltage source and the high-frequency inductor to be tested, to form a charging loop; A pulse signal generating unit, coupled to the charging switch, for providing a single pulse signal to control the conduction or cutoff of the charging switch; A discharging loop, including the high-frequency inductor, for providing a freewheeling loop for the high-frequency inductor when the charging loop is disconnected; A current testing unit, serially connected to the high-frequency inductor, for detecting the real-time current of the high-frequency inductor; A voltage testing unit, connected in parallel with the high-frequency inductor, for detecting the real-time voltage of the high-frequency inductor; A display unit, respectively connected to the output end of the current testing unit and the output end of the voltage testing unit, for displaying the variation of the real-time current and real-time voltage of the high-frequency inductor.

2. The high-frequency inductor saturation current testing device according to claim 1, characterized in that, The discharging loop further includes a first discharging switch, which is connected in parallel with the high-frequency inductor to form the discharging loop.

3. The high-frequency inductor saturation current testing device according to claim 1, characterized in that The discharging loop further includes a second discharging switch and a third discharging switch, and the DC voltage source, the second discharging switch, the high-frequency inductor and the third discharging switch are serially connected to form the discharging loop.

4. The high-frequency inductor saturation current testing device according to claim 1, wherein The charging loop further includes a loop protection component for providing charging protection for the high-frequency inductor, and the loop protection component is serially connected to the charging switch, the DC voltage source and the high-frequency inductor to form the charging loop.

5. The high-frequency inductor saturation current testing device according to claim 2, wherein The discharging loop further includes a discharging resistor for consuming the stored energy in the high-frequency inductor, and the discharging resistor is serially connected with the first discharging switch to form a discharging branch, and the discharging branch is connected in parallel with the high-frequency inductor.

6. The high-frequency inductor saturation current testing device according to any one of claims 1 to 5, characterized in that, The preset ideal signal width of the pulse signal generating unit satisfies the following condition: S=(1.5*a*L0) / V; Wherein, S is the preset ideal signal width of the pulse signal generating unit, a is the saturation current value of the high-frequency inductor, L0 is the initial inductance of the high-frequency inductor, and V is the voltage value of the DC voltage source.

7. The high-frequency inductor saturation current testing device according to claim 1 or 4, characterized in that The charging switch adopts MOSFET or IGBT.

8. The high-frequency inductance saturation current testing device according to claim 1, wherein The display unit adopts an oscilloscope.

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