Inductance value test circuit adopting Rogowski coil

Abstract

The utility model provides an inductance value test circuit adopting a Rogowski coil, which is used for measuring the inductance value of an inductor to be measured under the condition of direct current bias, and comprises the inductor to be measured, the inductor to be measured is positioned in an inductance branch, the Rogowski coil is positioned in the inductance branch, and the Rogowski coil is positioned in the inductance branch. And the inductance branch passes through the hollow part of the Rogowski coil. And obtaining the inductance value of the inductor to be tested according to the voltage at the two ends of the inductor to be tested, the output voltage of the Rogowski coil and the mutual inductance coefficient of the Rogowski coil by adopting an inductance value testing method of the Rogowski coil. According to the inductance value test circuit adopting the Rogowski coil, the inductance value of the to-be-tested inductor is calculated by using the sampling instantaneous value instead of the sampling difference value, the inductance value of the to-be-tested inductor can be effectively obtained, the calculation is simple, the precision is high, and especially when the current of the to-be-tested inductor is small, the accuracy is high. The problem that the inductance value of the to-be-measured inductor cannot be obtained due to the fact that the effective current difference value cannot be obtained due to too large jitter can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and particularly relates to an inductance value testing circuit adopting a Rogowski coil. Background Art

[0002] An inductor is an electronic component that has the property of impeding the change of current. An inductor is composed of a coil or a combination of coils. When current passes through the coil, a magnetic field will be generated and electrical energy will be stored.

[0003] There are two existing methods for testing inductors:

[0004] One is the pulse method. The pulse method generates a large pulse current in the inductor to be tested, and the inductance value can be calculated according to the pulse current curve and the inductor voltage. The disadvantage is that there is a large deviation due to eddy current loss.

[0005] The other is the DC method. The DC source provides a large continuous DC flowing through the inductor; then a small pulse current is generated in the inductor to be tested, and the inductance value can be calculated according to the pulse current curve and the inductor voltage. The disadvantage is that for different DC currents, different DC sources need to be matched, which is difficult, large in volume and high in cost. Summary of the Utility Model

[0006] The purpose of the utility model is to provide an inductance value testing circuit and method adopting a Rogowski coil to solve the problems of large difficulty and low accuracy in the existing calculation methods of inductor inductance values.

[0007] The utility model provides an inductance value testing circuit adopting a Rogowski coil for measuring the inductance value of an inductor to be tested under a DC bias condition, including the inductor to be tested, where the inductor to be tested is located in an inductor branch, and further includes a Rogowski coil, and the inductor branch passes through the hollow part of the Rogowski coil.

[0008] Further, the inductor branch includes a DC source, a first switching tube, and the inductor to be tested, and the DC source, the first switching tube, and the inductor to be tested are connected in series to form a first current loop.

[0009] Further, the inductor branch further includes a freewheeling diode, a current limiting resistor, and the inductor to be tested, and the freewheeling diode, the current limiting resistor, and the inductor to be tested are connected in series to form a second current loop.

[0010] Further, it further includes a first voltage tester and a second voltage tester, which are respectively used for testing the voltage across the inductor to be tested and the output voltage of the Rogowski coil.

[0011] Further, it further includes a first current tester for measuring the current of the inductor to be tested.

[0012] Further, the DC power source is a battery or an AC-DC power source.

[0013] Further, the AC-DC power source is an isolated AC-DC power source.

[0014] Further, the first switching tube is any one of an IGBT, a MOSFET, a triode, a relay, and a contactor.

[0015] Further, the first current tester is a Hall sensor or a CT.

[0016] Further, the isolated AC-DC power source includes an AC input terminal, a transformer, a rectifier bridge, a DC-DC conversion circuit, and a capacitor connected in sequence.

[0017] The present utility model also discloses a method for testing the inductance value using a Rogowski coil, which is applied to the inductance value testing circuit using a Rogowski coil in the present utility model. According to the voltage across the inductance to be measured, the output voltage of the Rogowski coil, and the mutual inductance coefficient of the Rogowski coil, the inductance value of the inductance to be measured is obtained.

[0018] Further, the calculation method (formula) for obtaining the inductance value of the inductance to be measured is: L_test = M * V1(t) / e(t), where M is the mutual inductance coefficient of the Rogowski coil, V1(t) is the voltage across the inductance to be measured, and e(t) is the output voltage of the Rogowski coil.

[0019] Further, the calculation method (formula) for obtaining the inductance value of the inductance to be measured is: L_test = M * (V1(t) - i(t) * R_L) / e(t), where M is the mutual inductance coefficient of the Rogowski coil, R_L is the resistance value of the equivalent series resistance of the inductance to be measured, V1(t) is the voltage across the inductance to be measured, e(t) is the output voltage of the Rogowski coil, and i(t) is the current of the inductance to be measured.

[0020] The above-mentioned inductance value testing circuit and method using a Rogowski coil utilize the sampling instantaneous value instead of the sampling difference to calculate the inductance value of the inductance to be measured, can effectively obtain the inductance value of the inductance to be measured, has simple calculation and high precision. Especially when the current of the inductance to be measured is small, it can avoid the problem that the current difference cannot be obtained effectively due to excessive jitter, resulting in inability to calculate. Description of the Drawings

[0021] Figure 1 is the circuit diagram of the inductance value testing circuit using a Rogowski coil in an embodiment of the present utility model;

[0022] Figure 1-1 is the circuit diagram of the inductance value testing circuit using a Rogowski coil in another embodiment of the present utility model;

[0023] Figure 1-2 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0024] Figure 1-3 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0025] Figure 2 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0026] Figure 2-1 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0027] Figure 2-2 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0028] Figure 2-3 The circuit diagram of the inductance value test circuit using a Rogowski coil in another embodiment of the present utility model;

[0029] Figure 3 is Figure 1 、 2 the waveforms of the voltage V1(t) across the inductor under test, the output voltage e(t) of the Rogowski coil, and the current i(t) passing through the inductor under test in the embodiment;

[0030] Figure 4 It is the DC bias curve graph of the inductor.

[0031] Figure 5 A schematic diagram of an AC-to-DC power supply in an embodiment of the present utility model;

[0032] Description of the main component symbols:

[0033] DC source 10 Freewheeling diode 60 First switching tube 20 First voltage tester 70 Inductor under test 30 Second voltage tester 80 Rogowski coil 40 First current tester 90 Current limiting resistor 50 Equivalent series resistance 100 Hollow part of the Rogowski coil 41 Inductor branch 200

[0034] The following specific embodiments will further illustrate the present utility model in conjunction with the above-mentioned drawings. Specific Embodiments

[0035] To facilitate the understanding of the present utility model, the present utility model will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present utility model are shown in the drawings. However, the present utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present utility model more thorough and comprehensive.

[0036] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this utility model belongs. The terms used herein in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] Please refer to Figure 1 , a sense value test circuit using a Rogowski coil provided by an embodiment of the present utility model is used to measure the sense value of an inductor 30 to be measured under a DC bias condition, and includes a DC source 10, a first switching tube 20, an inductor 30 to be measured, a Rogowski coil 40, a current limiting resistor 50, and a freewheeling diode 60; the inductor 30 to be measured, the freewheeling diode 60, and the current limiting resistor 60 are connected in series to form a freewheeling circuit (second current circuit);

[0039] Among them, the Rogowski coil is also called a current measurement coil and a differential current sensor, and is a toroidal coil uniformly wound on a non-ferromagnetic material.

[0040] The inductor 30 to be measured, the DC source 10, and the first switching tube 20 are connected in series to form a first current circuit. The first current circuit passes through the hollow part of the Rogowski coil. The freewheeling circuit also passes through the hollow part of the Rogowski coil. Or rather, the common part of the first current circuit and the freewheeling circuit passes through the hollow part of the Rogowski coil. The working principle is that when the first switching tube 20 is turned on, the DC source 10 discharges after passing through the first switching tube 20, and the first current circuit works; after the first switching tube 20 is turned off, the first current circuit does not work, and the freewheeling circuit works. The freewheeling circuit is used to discharge energy. The present utility model also discloses a sense value test method using a Rogowski coil. When the above first current circuit or freewheeling circuit is working, according to the voltage V1(t) across the inductor 30 to be measured, the output voltage e(t) of the Rogowski coil 40, and the mutual inductance coefficient M of the Rogowski coil 40, the sense value L_test of the inductor 30 to be measured is obtained, that is, L_test = M * V1(t) / e(t); it should be noted that V1(t) and e(t) are the corresponding voltages at time t, or rather the instantaneous values of the corresponding voltages. The i(t) herein is the current at time t, or rather the instantaneous value of the current.

[0041] The specific derivation process of \(L_{test}=M\times V1(t) / e(t)\) is as follows: Since the inductance calculation method (formula) of the to-be-tested inductor 30 is \(L_{test}=V1(t) / (di(t) / dt)\), which is called Formula 1, where \(di(t)\) is the current change amount passing through the to-be-tested inductor 30 within \(dt\) time, and \(di(t) / dt\) is the current change rate passing through the to-be-tested inductor 30. The output voltage \(e(t)\) of the Rogowski coil 40 is \(e(t)=M\times di(t) / dt\), which is called Formula 2 (where \(M = \mu_0\times N\times h\times\ln(b / a) / 2\pi\), \(\mu_0\) is the vacuum permeability, \(N\) is the number of coil turns, \(h\) is the skeleton height, and \(a\) and \(b\) are the inner and outer diameters of the cross-section of the skeleton respectively. This formula shows that the mutual inductance coefficient \(M\) is directly proportional to the number of coil turns \(N\) and the skeleton height \(h\). Therefore, to increase the mutual inductance coefficient, it can be achieved by increasing the skeleton height and the number of coil turns. At the same time, the mutual inductance coefficient \(M\) also has a corresponding relationship with the inner and outer diameters of the skeleton. By expanding the outer diameter of the skeleton or reducing the inner diameter of the skeleton, the value of the mutual inductance coefficient can also be increased.), According to Formula 2, we can get \(di(t) / dt = e(t) / M\), which is called Formula 3. Substituting Formula 3 into Formula 1, we can get \(L_{test}=M\times V1(t) / e(t)\). Since \(M\) is known or can be obtained / calculated, and the voltage \(V1(t)\) across the to-be-tested inductor 30 and the output voltage \(e(t)\) of the Rogowski coil 40 can be measured, the inductance value of the to-be-tested inductor 30 can be obtained according to the formula \(L_{test}=M\times V1(t) / e(t)\).

[0042] In one embodiment, the inductance value testing circuit of the present utility model using a Rogowski coil further includes a first voltage tester 70 and a second voltage tester 80, which are respectively used to test the voltage \(V1(t)\) across the to-be-tested inductor 30 and the output voltage \(e(t)\) of the Rogowski coil 40.

[0043] In one embodiment, the inductance value testing circuit of the present utility model using a Rogowski coil further includes a first current tester 90, which is used to measure the current \(i(t)\) of the to-be-tested inductor 30, obtain the current \(i(t)\) of the to-be-tested inductor 30 in real time, and can also obtain the current peak moment \(T_{peak}\) passing through the to-be-tested inductor 30 when the first current loop is working (see Figure 3), to turn off (disconnect) the first switching transistor Q1, the first current loop is disconnected, the first current loop does not work, and the freewheeling loop for discharging the inductor energy starts to work, and the current passing through the inductor under test 30 and the Rogowski coil 40 decreases. Before the current of the inductor under test 30 reaches the pulse current peak Ipk, the first switching transistor 20 conducts, the first current loop works, the DC source 10 discharges after passing through the first switching transistor 20, and the current passing through the inductor under test 30 rises. When the first current loop works, the inductance value of the inductor under test 30 during the entire current change process (current from 0 to the current peak Ipk) can be obtained; of course, according to requirements, the first switching transistor Q1 can also be turned off (disconnected) when the current of the inductor under test 30 does not reach the current peak (at this time, the current of the inductor under test 30 is Im, 0 < Im < Ipk). When the first current loop works, the inductance value of the inductor under test 30 during the period when the current is from 0 to Im can be obtained. At the current peak moment Tpeak (see Figure 3 ) after that, the freewheeling loop works, and the inductance value of the inductor under test 30 during the period when the current is from Ipeak to 0 can be obtained; or according to requirements, the inductance value of the inductor under test 30 during the period when the current is from Ipeak to In (at this time, the current of the inductor under test 30 is In, 0 < In < Ipk) can be obtained. Whether in the working stage of the first current loop or the working stage of the freewheeling loop, the calculation formula for the inductance value L_test of the inductor under test 30 is M * V1(t) / e(t).

[0044] Please refer to Figure 1-1 , a kind of inductance value test circuit using a Rogowski coil provided by another embodiment of the present invention is different from Figure 1 the embodiment in that the first current loop passes through the hollow part of the Rogowski coil, and the freewheeling loop does not pass through the hollow part of the Rogowski coil. In Figure 1-1 the embodiment, the inductance value of the inductor under test 30 when the first current loop works can be calculated, and the specific calculation method is the same as Figure 1 the calculation of the inductance value of the inductor under test 30 when the first current loop works in the embodiment.

[0045] Please refer to Figure 1-2 , a kind of inductance value test circuit using a Rogowski coil provided by another embodiment of the present invention is different from Figure 1 the embodiment in that the freewheeling loop passes through the hollow part of the Rogowski coil, and the first current loop does not pass through the hollow part of the Rogowski coil. In L the embodiment, the inductance value of the inductor under test 30 when the freewheeling loop works can be calculated, and the specific calculation method is the same as Figure 1-2 the calculation of the inductance value of the inductor under test 30 when the freewheeling loop works in the embodiment.

[0046] Please refer toFigure 1 , a sense value test circuit using a Rogowski coil provided by another embodiment of the present utility model includes a to-be-tested inductor 30, and the to-be-tested inductor 30 is located in an inductor branch 200. The sense value test circuit further includes a Rogowski coil 40, and the inductor branch 200 passes through the hollow part of the Rogowski coil 40. Combining the foregoing description, it can be known that when current flows through the to-be-tested inductor 30, as long as the voltage V1(t) across the to-be-tested inductor 30 and the output voltage e(t) of the Rogowski coil 40 are obtained, the sense value of the to-be-tested inductor 30 can be obtained according to the formula L_test = M * V1(t) / e(t). Among them, the inductor branch 200 can be the foregoing first current loop, or the foregoing second current loop, or other styles.

[0047] Please refer to Figure 1-3 , a sense value test circuit using a Rogowski coil provided by another embodiment of the present utility model, is different from Figure 2 the embodiment in that Figure 1 the embodiment takes into account the resistance R_L of the equivalent series resistance 100 of the to-be-tested inductor 30 (R_L can be obtained according to the specification of the to-be-tested inductor 30, etc.). Then, the calculation method (formula) of the sense value of the to-be-tested inductor 30 at this time becomes: L_test = M * (V1(t) - i(t) * R_L) / e(t). This is because, considering the resistance R_L of the equivalent series resistance 100 of the to-be-tested inductor 30, the voltage across the equivalent series resistance 100 is i(t) * R_L, and the actual voltage across the to-be-tested inductor 30 is V1(t) - i(t) * R_L. Substituting V1(t) in the formula L_test = M * V1(t) / e(t) of Embodiment 1 with (V1(t) - i(t) * R_L), the calculation method (formula) of the sense value of the to-be-tested inductor 30, L_test = M * (V1(t) - i(t) * R_L) / e(t), can be obtained. Since Embodiment 2 takes into account the voltage division of the equivalent series resistance 100 of the to-be-tested inductor 30, the accuracy of the sense value of the to-be-tested inductor 30 obtained through Embodiment 2 is higher than that of Embodiment 1. Whether in the working stage of the first current loop or the freewheeling loop working stage, the calculation formula of the sense value L_test of the to-be-tested inductor 30 is M * (V1(t) - i(t) * R_L) / e(t).

[0048] Please refer to Figure 2 , a sense value test circuit using a Rogowski coil provided by another embodiment of the present utility model, is different from Figure 2-1 the embodiment in that the first current loop passes through the hollow part of the Rogowski coil, and the freewheeling loop does not pass through the hollow part of the Rogowski coil. In Figure 2 this embodiment, the sense value of the to-be-tested inductor 30 during the working of the first current loop can be calculated, and the specific calculation method is the same as Figure 2-1Calculation of the inductance value of the to-be-tested inductor 30 when the first current loop is working.

[0049] Please refer to Figure 2 , a kind of inductance value test circuit using a Rogowski coil provided by another embodiment of the present invention, is different from Figure 2-2 the embodiment in that the freewheeling loop passes through the hollow part of the Rogowski coil, and the first current loop does not pass through the hollow part of the Rogowski coil. In Figure 2 the embodiment, the inductance value of the to-be-tested inductor 30 when the freewheeling loop is working can be calculated, and the specific calculation method is the same as Figure 2-2 the calculation of the inductance value of the to-be-tested inductor 30 when the freewheeling loop is working in the embodiment.

[0050] Please refer to Figure 2 , a kind of inductance value test circuit using a Rogowski coil provided by another embodiment of the present invention, is different from Figure 2-3 the embodiment in that Figure 1-3 the embodiment takes into account the resistance value R_L of the equivalent series resistance 100 of the to-be-tested inductor 30. Combining the foregoing description, when current flows through the to-be-tested inductor 30, as long as the voltage V1(t) across the to-be-tested inductor 30 and the output voltage e(t) of the Rogowski coil 40 are obtained, the inductance value of the to-be-tested inductor 30 can be obtained according to the formula L_test = M * (V1(t) - i(t) * R_L) / e(t). Among them, the inductor branch 200 can be the foregoing first current loop, or the foregoing second current loop, or other styles.

[0051] Figure 2-3 The entire view of Figure 3 / 2 shows the waveform of the voltage V1(t) across the to-be-tested inductor, the waveform of the output voltage e(t) of the Rogowski coil, and the waveform of the current i(t) passing through the to-be-tested inductor. According to the foregoing description, it can be known that at any moment when the current of the to-be-tested inductor 30 changes from 0 to the peak value, and / or at any moment when the current of the to-be-tested inductor 30 changes from the peak value to 0, the corresponding voltage V1(t) across the inductor, the output voltage e(t) of the Rogowski coil, and the current i(t) passing through the to-be-tested inductor can be obtained, and the inductance value of the to-be-tested inductor 30 at any moment when the current of the to-be-tested inductor 30 changes from 0 to the peak value can be calculated (according to the formula L_test = M * V1(t) / e(t), or the formula L_test = M * (V1(t) - i(t) * R_L) / e(t)), that is, the inductance value of the to-be-tested inductor 30 can be calculated according to the instantaneous values of the voltage (and current).

[0052] In addition, Figure 1 the voltage and current in the 0-Tpeak stage of Figure 3 respectively correspond to Figure 1-1The waveforms of the voltage V1(t) across the inductor under test, the output voltage e(t) of the Rogowski coil, and the current i(t) through the inductor under test in the first current loop working stage of the circuit of the embodiment.

[0053] In addition, Figure 2-1 the voltages and currents of Tpeak - Tmin respectively correspond to Figure 3 , Figure 2-1 The waveforms of the voltage V1(t) across the inductor under test, the output voltage e(t) of the Rogowski coil, and the current i(t) through the inductor under test in the freewheeling loop working stage of the circuit in the embodiment.

[0054] In the above - mentioned embodiment, the DC source 10 can be a battery or an AC - to - DC source.

[0055] In one embodiment, the AC - to - DC source is isolated. For example, it can be the circuit shown in Figure 2-2 , that is, it consists of an AC input terminal 1, a transformer 2, a rectifier bridge 3, a DC - DC conversion circuit 4, and a capacitor 5. The AC input terminal 1 connects the alternating current to the primary side of the transformer 2. The secondary side of the transformer 2 is connected to the input terminal of the DC - DC conversion circuit 4. The output terminal of the DC - DC conversion circuit 4 is connected to the capacitor 5. Both ends of the capacitor 5 are the two ends of the DC source 10. Among them, the DC - DC conversion circuit 4 is a boost circuit (such as the circuit within the dotted line in Figure 5 ); in another embodiment, the DC - DC conversion circuit 4 can also be a buck circuit or a buck - boost circuit; in another embodiment, the DC - DC conversion circuit 4 can also be omitted, and the output terminal of the rectifier bridge 3 is directly connected to both ends of the capacitor 5. When the AC - to - DC source is isolated, since the primary and secondary sides are electrically isolated, electric shock to the human body can be avoided during the test, improving the safety during the test.

[0056] In the above - mentioned embodiment, the first current tester 90 is a Hall sensor, a CT, etc.

[0057] In the above - mentioned embodiment, the first switching tube can be a controllable switch such as an IGBT, a MOSFET, a triode, a relay, a contactor, etc.

[0058] In the above - mentioned embodiment, if the maximum current Ipk is small, the number of the first switching tubes is 1; if the maximum current Ipk is large, the first switching tube can be composed of two or more switching tubes in parallel; that is, the number of the first switching tubes can be adjusted adaptively according to the magnitude of the maximum current Ipk.

[0059] In the above - mentioned embodiment, the output voltage of the DC source 10 is 180V; in actual needs, the output voltage of the DC source 10 can be 50V - 1000V, or other voltage ranges can be selected according to actual needs.

[0060] In addition,Figure 5 It is a DC bias curve graph of an inductor, where the horizontal axis current represents the DC bias current, Figure 4 Figure 4 showing the corresponding relationship of the inductor values under different DC bias currents. It can be seen that before the DC bias current reaches the peak current, the inductance (inductance value) of the inductor changes with the change of the current. More specifically, the inductance (inductance value) of the inductor decreases as the current increases, or alternatively, the inductance (inductance value) of the inductor increases as the current decreases; from the above description of the present invention, the present invention can adopt a Rogowski coil to sample the instantaneous value of the voltage (and current) instead of sampling the difference to calculate the inductance value of the to-be-detected inductor 30 under different current conditions (within the range from 0 to the current peak, or / and within the range from the current peak to 0). The calculation is simple and has high precision. Especially when the current of the to-be-detected inductor is small, it can avoid the problem that the jitter is too large to obtain an effective current difference, resulting in the inability to calculate.

[0061] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. An inductance value test circuit using a Rogowski coil, including an inductor under test, the inductor under test is located in an inductor branch, and is characterized in that, It further includes a Rogowski coil, and the inductance branch passes through the hollow part of the Rogowski coil; the inductance branch includes a DC source, a first switching tube, and an inductor under test, and the DC source, the first switching tube, and the inductor under test are connected in series to form a first current loop; the inductance branch further includes a freewheeling diode, a current-limiting resistor, and an inductor under test, and the freewheeling diode, the current-limiting resistor, and the inductor under test are connected in series to form a second current loop.

2. The inductance value test circuit using a Rogowski coil according to claim 1, characterized in that It further includes a first voltage tester and a second voltage tester, which are respectively used to test the voltage across the inductor under test and the output voltage of the Rogowski coil.

3. The inductance value testing circuit using a Rogowski coil according to claim 1, characterized in that, It further includes a first current tester, which is used to measure the current of the inductor under test.

4. The inductance value testing circuit using a Rogowski coil according to claim 3, characterized in that The first current tester is a Hall sensor or a CT.

5. The inductance value testing circuit using a Rogowski coil according to claim 1, characterized in that, The DC source is a battery or an AC-DC power supply.

6. The inductance value test circuit using a Rogowski coil according to claim 1, characterized in that The first switching tube is any one of an IGBT, a MOSFET, a triode, a relay, and a contactor.

7. The inductance value testing circuit using a Rogowski coil according to claim 5, characterized in that, The AC-DC power supply is an isolated AC-DC power supply.

8. The inductance value testing circuit using a Rogowski coil according to claim 7, characterized in that The isolated AC-DC power supply includes an AC input terminal, a transformer, a rectifier bridge, a DC-DC conversion circuit, and a capacitor connected in sequence.

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