Internal resistance test circuit and internal resistance test device
By configuring a magnetic field cancellation unit to offset the magnetic field influence of the inductor element, the rapid and accurate measurement of the internal resistance of the motor coil and transformer coil of the new energy vehicle is achieved, and the problems of inaccurate measurement and time-consuming in the prior art are solved.
Patent Information
- Application Number
- CN202521106971.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2035-06-03
AI Technical Summary
The prior art cannot accurately measure composite resistances with significant inductance characteristics, especially in the internal resistance measurement of new energy vehicle motor coils or transformer coils, resulting in inaccurate measurement results and long time.
A magnetic field cancellation unit is arranged to induce the electromagnetic field of the inductor element to be measured through the inductor part and generate a reverse magnetic field using the amplification part and the magnetic field cancellation part to offset the influence of the magnetic field of the inductor part, thereby realizing rapid internal resistance testing.
It significantly improves the testing efficiency and accuracy, reduces the impact of inductive heating on the test results, and improves the measurement accuracy.
Smart Images
Figure CN223078398U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of internal resistance testing, and particularly relates to an internal resistance testing circuit and an internal resistance testing device. Background Art
[0002] At present, the pure resistance measurement technology has been quite mature; however, with the continuous progress of technology, especially in the context of the rapid development of new energy vehicle technology, the resistors involved in resistance testing in many application scenarios are not simple resistors, but composite resistors containing inductance components.
[0003] Taking the new energy vehicle industry as an example, during the vehicle maintenance process, it is often necessary to measure the resistance of motor coils or transformer coils. These resistors are not pure resistors, but composite resistors with significant inductance characteristics, and the resistance values of such resistors cannot be accurately measured by traditional multimeters.
[0004] Specifically, please refer to Figure 1 and Figure 2 , Figure 1 Figure (a) in Figure 1 shows the circuit structure diagram when using a multimeter to measure the resistance of a motor coil, Figure 2 Figure (a) in Figure 2 shows the circuit structure diagram when using a multimeter to measure the resistance of a motor coil containing an inductive element, Figure 1 Figure (b) in Figure 2 reveals the changes in current and voltage during the measurement process. In view of the existence of the inductive element, this inductance factor must be considered in the test principle; by comparison, the existence of inductance causes the current to rise not to show the rapid rising trend of the square wave shown in
[0005] Figure (b) in Summary of the Utility Model
[0006] In view of the deficiencies of the above-mentioned prior art, the purpose of the present utility model is to provide an internal resistance testing circuit, which cancels the magnetic field of the inductive element to be measured through the configuration of a magnetic field cancellation unit, realizes rapid internal resistance testing, improves the testing accuracy, eliminates magnetic field interference, and improves the measurement accuracy.
[0007] In order to achieve the above purpose, the present utility model adopts the following technical solutions:
[0008] An internal resistance testing circuit includes a magnetic field cancellation unit and a testing unit. The magnetic field cancellation unit includes an induction part and a magnetic field cancellation part. The induction end of the induction part is used to sense the electromagnetic field generated by the inductive element to be measured. The output end of the induction part is connected to the input end of the magnetic field cancellation part. The magnetic field cancellation part is used to generate a reverse magnetic field to cancel the magnetic field of the inductive element to be measured. The testing unit is used to detect the internal resistance of the inductive element to be measured.
[0009] In the internal resistance testing circuit, an amplification part is further included. The output end of the induction part is connected to the input end of the magnetic field cancellation part through the amplification part.
[0010] In the internal resistance testing circuit, the amplification part includes an operational amplifier U1 and a capacitor C1. The first pin of the operational amplifier U1 and one end of the capacitor C1 are respectively connected to the output end of the induction part. The second pin of the operational amplifier U1 and the other end of the capacitor C1 are respectively connected to the input end of the magnetic field cancellation part. The third pin of the operational amplifier U1 is grounded.
[0011] In the internal resistance testing circuit, the induction part includes a servo coil LADD. One end of the servo coil LADD is connected to the first pin of the operational amplifier U1 and one end of the capacitor C1. The other end of the servo coil LADD is grounded. The servo coil LADD is used to sense the electromagnetic field generated by the inductive element to be measured and feedback the induced current to the amplification part.
[0012] In the internal resistance testing circuit, the magnetic field cancellation part includes a secondary side coil LS. One end of the secondary side coil LS is connected to the second pin of the operational amplifier U1 and the other end of the capacitor C1. The other end of the secondary side coil LS is grounded. The secondary side coil LS is used to generate a magnetic field with the same intensity and opposite direction as the magnetic field of the inductive element to be measured to cancel the magnetic field of the inductive element to be measured.
[0013] In the internal resistance testing circuit, the induction part includes a Hall sensor. The Hall sensor is used to sense the electromagnetic field generated by the inductive element to be measured. The Vout pin of the Hall sensor is connected to the input end of the magnetic field cancellation part.
[0014] In the internal resistance test circuit described above, the test unit includes a voltmeter, and both ends of the voltmeter are respectively used to connect both ends of the inductive element to be measured.
[0015] The present utility model also correspondingly provides an internal resistance test device, characterized in that the internal resistance test device uses the internal resistance test circuit described in any one of the above to implement the internal resistance test of the inductive element to be measured.
[0016] Beneficial effects:
[0017] The present utility model provides an internal resistance test circuit. By configuring a magnetic field cancellation unit to cancel the magnetic field of the inductive element to be measured, the internal resistance test process of the inductive element to be measured can be carried out as quickly as a pure resistance test, significantly improving the test efficiency. At the same time, due to the acceleration of the test speed, the influence of inductance heating on the test result is reduced, thereby improving the accuracy of the test result. In addition, by using the magnetic field cancellation unit to eliminate the magnetic field influence of the inductive element to be measured, interference factors are reduced, further improving the measurement accuracy. Description of the drawings
[0018] Figure 1 In (a), it is the circuit structure diagram when using a multimeter to measure the resistance of a motor coil.
[0019] Figure 1 In (b), it is the change situation of current and voltage during the process of using a multimeter to measure the resistance of a motor coil.
[0020] Figure 2 In (a), it is the circuit structure diagram when using a multimeter to measure the resistance of a motor coil containing an inductive element.
[0021] Figure 2 In (b), it is the change situation of current and voltage during the process of using a multimeter to measure the resistance of a motor coil containing an inductive element.
[0022] Figure 3 It is the circuit block diagram of an embodiment of the magnetic field cancellation unit provided by the present utility model.
[0023] Figure 4 It is the circuit schematic diagram of an embodiment of the magnetic field cancellation unit provided by the present utility model.
[0024] Figure 5 It is the circuit schematic diagram of another embodiment of the magnetic field cancellation unit provided by the present utility model.
[0025] Figure 6 It is the change situation of current and voltage when the internal resistance test circuit of this embodiment is used to detect the internal resistance of an inductive element.
[0026] Description of main component symbols: 1 - magnetic field cancellation unit, 11 - induction part, 12 - amplification part, 13 - magnetic field cancellation part, 2 - test unit, 3 - inductance element under test. Detailed implementation mode
[0027] The present utility model provides an internal resistance test circuit and an internal resistance test device. To make the purpose, technical solution and effects of the present utility model clearer and more definite, the following further describes the present utility model in detail with reference to the accompanying drawings and by way of examples.
[0028] In the description of the present utility model, it should be understood that terms such as "installation" and "connection" should be understood in a broad sense. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.
[0029] Please refer to Figures 3 to 6 , the present utility model provides an internal resistance test circuit, including a magnetic field cancellation unit 1 and a test unit 2. The magnetic field cancellation unit 1 includes an induction part 11 and a magnetic field cancellation part 13. The induction end of the induction part 11 is used to sense the electromagnetic field generated by the inductance element 3 under test. The output end of the induction part 11 is connected to the input end of the magnetic field cancellation part 13. The magnetic field cancellation part 13 is used to generate a reverse magnetic field to cancel the magnetic field of the inductance element 3 under test. The test unit 2 is used to detect the internal resistance of the inductance element 3 under test.
[0030] Please refer to Figure 6 , this application discloses an internal resistance test circuit. By configuring the induction part 11 to sense the electromagnetic field of the inductance element 3 under test, an induced current is generated, which drives the magnetic field cancellation part 13 to generate a reverse magnetic field to cancel the magnetic field of the inductance element 3 under test. This process enables the internal resistance test of the inductance element 3 under test to be carried out as quickly as a pure resistance test, significantly improving the test efficiency. At the same time, the acceleration of the test speed reduces the influence of inductance heating on the test results, thereby improving the accuracy of the test results. In addition, the use of the magnetic field cancellation unit 1 eliminates the magnetic field influence of the inductance element 3 under test, reduces interference factors, and further improves the measurement accuracy.
[0031] In one embodiment, please refer to Figure 3 , the internal resistance test circuit further includes an amplification part 12. The output end of the induction part 11 is connected to the input end of the magnetic field cancellation part 13 through the amplification part 12.
[0032] In this embodiment, the amplification part 12 is used to process the induced current generated by the servo coil LADD, and then generate a compensation current, which is used to drive the secondary coil LS to generate a secondary magnetic field equal in magnetic field strength and opposite in direction to the magnetic field of the inductance element 3 under test, so as to eliminate the magnetic field influence of the inductance element 3 under test.
[0033] Further, please refer to Figure 4 , the amplifying section 12 includes an operational amplifier U1 and a capacitor C1. The first pin of the operational amplifier U1 and one end of the capacitor C1 are respectively connected to the output end of the induction section 11. The second pin of the operational amplifier U1 and the other end of the capacitor C1 are respectively connected to the input end of the magnetic field cancellation section 13. The third pin of the operational amplifier U1 is grounded.
[0034] In this embodiment, the working principle of the amplifying section 12 is as follows: When the servo coil LADD senses the electromagnetic field generated by the measured inductive element 3, an induced current will be generated. This induced current is then input to the integrating amplifier circuit, that is, the amplifying section 12. In the integrating amplifier circuit, the operational amplifier performs an integration operation process based on the input current signal and in combination with the characteristics of the capacitive element, and finally outputs a compensation current to the secondary coil LS.
[0035] Further, please refer to Figure 4 , the induction section 11 includes a servo coil LADD. One end of the servo coil LADD is connected to the first pin of the operational amplifier U1 and one end of the capacitor C1. The other end of the servo coil LADD is grounded. The servo coil LADD is used to sense the electromagnetic field generated by the measured inductive element 3 and feedback the induced current to the amplifying section 12.
[0036] Further, please refer to Figure 4 , the magnetic field cancellation section 13 includes a secondary coil LS. One end of the secondary coil LS is connected to the second pin of the operational amplifier U1 and the other end of the capacitor C1. The other end of the secondary coil LS is grounded. The secondary coil LS is used to generate a magnetic field with the same magnitude and opposite direction as the magnetic field of the measured inductive element 3 to cancel the magnetic field of the measured inductive element 3.
[0037] In this embodiment, when arranging the coils, the measured inductive element 3 should be placed at the center position as the source of the magnetic field. The servo coil LADD is closely wound around the outside of the measured inductive element 3 and adopts a coaxial winding method to ensure that it can evenly sense the electromagnetic field generated by the measured inductive element 3, so that the induced current accurately reflects the magnetic field strength of the measured inductive element 3. The secondary coil LS is placed outside the servo coil LADD in a coaxial manner with the measured inductive element 3 and maintains an appropriate distance to ensure that the generated reverse magnetic field can effectively cancel the magnetic field of the measured inductive element 3 while avoiding unnecessary electromagnetic coupling interference between the coils.
[0038] The above embodiment is applicable to the occasion where the internal space of the coil is limited or a Hall current sensor cannot be installed. In another embodiment, please refer to Figure 5, the induction unit 11 includes a Hall sensor for inducing the electromagnetic field generated by the inductive component 3 to be measured. The pin Vout of the Hall sensor is connected to the input end of the magnetic field cancellation unit 13. The magnetic field cancellation unit 13 includes a secondary coil LS. One end of the secondary coil LS is connected to the pin Vout of the Hall sensor, and the other end of the secondary coil LS is grounded. The secondary coil LS is used to generate a magnetic field with the same intensity and opposite direction as that of the inductive component 3 to be measured to cancel the magnetic field of the inductive component 3 to be measured.
[0039] In this embodiment, by configuring the Hall sensor to induce the electromagnetic field of the inductive component 3 to be measured, an induced current is generated, which drives the magnetic field cancellation unit 13 to generate a reverse magnetic field to cancel the magnetic field of the inductive component 3 to be measured. This process enables the internal resistance test of the inductive component 3 to be carried out as quickly as a pure resistance test, significantly improving the test efficiency. At the same time, the acceleration of the test speed reduces the influence of inductance heating on the test result, thereby improving the accuracy of the test result. In addition, the utilization of the magnetic field cancellation unit 1 eliminates the magnetic field influence of the inductive component 3 to be measured, reduces interference factors, and further improves the measurement accuracy.
[0040] Further, the test unit 2 includes a voltmeter. The two ends of the voltmeter are respectively used to connect the two ends of the inductive component 3 to be measured. The connection structure can refer to Figure 1 ; that is, by configuring the magnetic field cancellation unit 1, traditional voltmeters such as multimeters and SMU source meters can be used to measure the internal resistance of the inductive component 3 to be measured. Since the magnetic field cancellation unit 1 eliminates the influence of the self-inductance of the inductive component 3 to be measured, the measurement process of the inductive component 3 to be measured can be consistent with the measurement process of a pure resistance, significantly improving the test speed, accuracy and stability, and being suitable for the automation test environment in fields such as new energy vehicles.
[0041] The present utility model also correspondingly provides an internal resistance test device, characterized in that the internal resistance test device uses the internal resistance test circuit described in any one of the above to implement the internal resistance test of the inductive component 3 to be measured.
[0042] It can be understood that for those of ordinary skill in the art, equivalent substitutions or changes can be made according to the technical solution and the inventive concept of the present utility model, and all such changes or substitutions should fall within the protection scope of the present utility model.
Claims
1. An internal resistance test circuit, characterized in that It includes a magnetic field cancellation unit and a test unit. The magnetic field cancellation unit includes an induction part and a magnetic field cancellation part. The induction end of the induction part is used to sense the electromagnetic field generated by the inductive component under test. The output end of the induction part is connected to the input end of the magnetic field cancellation part. The magnetic field cancellation part is used to generate a reverse magnetic field to cancel the magnetic field of the inductive component under test; the test unit is used to detect the internal resistance of the inductive component under test.
2. The internal resistance test circuit according to claim 1, characterized in that, It further includes an amplification part. The output end of the induction part is connected to the input end of the magnetic field cancellation part through the amplification part.
3. The internal resistance test circuit according to claim 2, characterized in that, The amplification part includes an operational amplifier U1 and a capacitor C1. The first pin of the operational amplifier U1 and one end of the capacitor C1 are respectively connected to the output end of the induction part. The second pin of the operational amplifier U1 and the other end of the capacitor C1 are respectively connected to the input end of the magnetic field cancellation part. The third pin of the operational amplifier U1 is grounded.
4. The internal resistance test circuit according to claim 3, characterized in that, The induction part includes a servo coil LADD. One end of the servo coil LADD is connected to the first pin of the operational amplifier U1 and one end of the capacitor C1. The other end of the servo coil LADD is grounded; the servo coil LADD is used to sense the electromagnetic field generated by the inductive component under test and feedback the induced current to the amplification part.
5. The internal resistance test circuit according to claim 3, characterized in that, The magnetic field cancellation part includes a secondary coil LS. One end of the secondary coil LS is connected to the second pin of the operational amplifier U1 and the other end of the capacitor C1. The other end of the secondary coil LS is grounded; the secondary coil LS is used to generate a magnetic field with the same intensity and opposite direction as the magnetic field of the inductive component under test to cancel the magnetic field of the inductive component under test.
6. The internal resistance test circuit according to claim 1, wherein The induction part includes a Hall sensor. The Hall sensor is used to sense the electromagnetic field generated by the inductive component under test. The Vout pin of the Hall sensor is connected to the input end of the magnetic field cancellation part.
7. The internal resistance test circuit according to claim 1, wherein, The test unit includes a voltmeter. The two ends of the voltmeter are respectively used to connect the two ends of the inductive component under test.
8. An internal resistance testing device, characterized in that, The internal resistance test device realizes the internal resistance test of the inductive component under test by using the internal resistance test circuit according to any one of claims 1-7.