Rogowski coil precision checking system and method for crimping type IGBT current measurement

Abstract

The invention discloses a Rogowski coil precision checking system and method for crimping type IGBT current measurement, the system comprises a plurality of diversion bosses connected in parallel, and the method adopts a mode of measuring transfer impedance between the plurality of diversion bosses and a Rogowski coil to realize checking. The method comprises the following steps of: applying voltage to a first test port by using a signal generator, measuring the voltage of a second test port, calculating scattering parameters according to the voltage of the first test port and the voltage of the second test port, calculating input current of the first test port according to the scattering parameters, and measuring the voltage of a third test port (Rogowski coil) by using the signal generator. The transfer impedance is calculated according to the input current and the voltage of the third test port, finally the transfer impedance data between the first test port and the Rogowski coil in all the diversion bosses is analyzed, the anti-interference capability and the test precision of the Rogowski coil are evaluated, and the reliability of the current measurement result of the crimping type IGBT is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of electronic device current measurement, and in particular to a Rogowski coil accuracy calibration system and method for crimped IGBT current measurement. Background Art

[0002] Due to the limitation of the package size of Press Pack-Insulated Gate Bipolar Transistor (Press Pack-Insulated Gate Bipolar Transistor) and the requirements of the measured current waveform, the traditional current measurement method is not applicable. The Rogowski coil current sensor can be flexibly designed according to the package form of the press-fit IGBT and is suitable for high-frequency current signals. It is currently the best method for measuring the current of the press-fit IGBT chip. The Rogowski coil current sensor is used to measure the current of the press-fit IGBT chip, and its measurement accuracy directly affects the control accuracy and reliability of the press-fit IGBT. Therefore, it is very necessary to calibrate the test accuracy of the Rogowski coil current sensor.

[0003] The traditional Rogowski coil current sensor accuracy calibration method usually relies on the test of the network analyzer. However, the operation of the network analyzer requires professionals, and the operation process is relatively complicated, which makes the test process inconvenient. In addition, the test accuracy of the network analyzer is limited by the performance of the instrument itself, which is difficult to meet the calibration requirements of high-precision Rogowski coil current sensors. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a Rogowski coil accuracy calibration system and method for crimped IGBT current measurement, which can improve the convenience and accuracy of the Rogowski coil current sensor accuracy frequency domain calibration, thereby ensuring the reliability of the crimped IGBT current measurement results.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a Rogowski coil accuracy calibration system for crimped IGBT current measurement, comprising a plurality of current guiding bosses connected in parallel;

[0006] Each of the flow-guiding bosses comprises a first test port, a first grounding copper busbar, a first insulator, a Rogowski coil to be calibrated, a flow-through boss, a second insulator, a second grounding copper busbar, a second test port, and a plurality of resistors connected in parallel with the second test port;

[0007] The first test port is connected to the first grounding copper busbar, which is connected to the first insulator and then to one end of the current-passing boss, the Rogowski coil to be calibrated is nested on the current-passing boss, the other end of the current-passing boss is connected to the second insulator, the second insulator is connected to the second grounding copper busbar, and the second grounding copper busbar is connected to the second test port.

[0008] Preferably, the plurality of parallel flow-guiding bosses are arranged in a matrix.

[0009] Preferably, each of the resistors is a high-frequency non-inductive resistor.

[0010] Preferably, the ratio of each of the flow bosses to the flow bosses inside the press-fit IGBT to be tested is 1:1.

[0011] Preferably, the structure of each of the through-current bosses is consistent with the structure of the crimping boss of the crimping-type IGBT chip to be tested.

[0012] To solve the above technical problems, an embodiment of the present invention further provides a Rogowski coil accuracy calibration method for crimped IGBT current measurement, which is applied to any of the above Rogowski coil accuracy calibration systems for crimped IGBT current measurement, comprising:

[0013] Testing the transfer impedance between the first test port in each flow guide boss and the Rogowski coil to be calibrated;

[0014] According to the transfer impedance between the first test port in all the flow guide bosses and the Rogowski coil to be calibrated, the anti-interference capability and the test accuracy of all the Rogowski coils to be calibrated are calibrated.

[0015] Preferably, the step of testing the transfer impedance between the first test port in each flow guiding boss and the Rogowski coil to be calibrated comprises:

[0016] Using a signal generator, providing a matching test resistor to the second test port, applying a voltage to the first test port, and testing the voltage of the second test port;

[0017] calculating a scattering parameter between the first test port and the second test port according to an applied voltage at the first test port and a voltage at the second test port;

[0018] Calculating an input current of the first test port according to a scattering parameter between the first test port and the second test port;

[0019] A signal generator is used to provide a matching test resistor to the third test port, and the voltage of the third test port is tested; wherein the third test port is formed by the Rogowski coil to be calibrated;

[0020] The transfer impedance between the first test port and the Rogowski coil to be calibrated is calculated according to the input current of the first test port and the voltage of the third test port.

[0021] Specifically, the scattering parameter between the first test port and the second test port is calculated by the following formula:

[0022]

[0023] Wherein, U1 is the applied voltage of the first test port; U2 is the voltage of the second test port.

[0024] Specifically, the input current of the first test port is calculated by the following formula:

[0025]

[0026] Wherein, R is the resistance value of a plurality of resistors connected in parallel with the second test port; and R2 is the resistance value given to the second test port for matching test.

[0027] Specifically, the transfer impedance between the first test port and the Rogowski coil to be calibrated is calculated by the following formula:

[0028]

[0029] Wherein, U3 is the voltage of the third test port.

[0030] Compared with the prior art, the embodiment of the present invention provides a Rogowski coil accuracy calibration system and method for crimped IGBT current measurement, the system includes a plurality of parallel conducting bosses, and the method adopts the method of measuring the transfer impedance between a plurality of conducting bosses and the Rogowski coil to realize the calibration. First, a signal generator is used to apply voltage to the first test port, and the voltage of the second test port is measured, and the scattering parameter is calculated according to the voltage of the first and second test ports, and the input current of the first test port is calculated according to the scattering parameter, and then the signal generator is used to measure the voltage of the third test port (Rogowski coil), and the transfer impedance is calculated according to the input current and the voltage of the third test port. Finally, the transfer impedance data between the first test port and the Rogowski coil in all the conducting bosses are analyzed to evaluate the anti-interference ability and test accuracy of the Rogowski coil, and ensure the reliability of the crimped IGBT current measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the drawings used in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a schematic structural diagram of a Rogowski coil provided by an embodiment of the present invention;

[0033] Figure 2 It is a structural schematic diagram of a Rogowski coil accuracy calibration system for crimp-type IGBT current measurement provided by an embodiment of the present invention;

[0034] Figure 3 It is a flow chart of a Rogowski coil accuracy calibration method for crimp-type IGBT current measurement provided by an embodiment of the present invention;

[0035] Figure 4 It is another flow chart of a Rogowski coil accuracy calibration method for crimped-type IGBT current measurement provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that, in order to solve the problem that current current sensors cannot meet the current measurement requirements of crimped IGBT chips, the embodiments of the present invention propose a frequency domain calibration method for Rogowski coil test accuracy of crimped IGBT current measurement.

[0038] It should be noted that the structure of the Rogowski coil includes two major components: first, a frame with a uniform cross-sectional area, and second, a tightly and evenly wound coil. The Rogowski coil current sensor also integrates the Rogowski coil and the integrator. The specific structure is as follows Figure 1 shown.

[0039] Among them, the Rogowski coil is a closed coil, which is essentially a wire evenly wound on a non-magnetic ring frame with a constant cross-section. According to the law of electromagnetic induction, the voltage induced by the coil is proportional to the differential of the current passing through the loop. When the signal is integrated by an integrator, the final output voltage of the sensor is proportional to the measured current, that is:

[0040]

[0041] At present, the Rogowski coil current sensor is an ideal large current detection technology. On the one hand, it does not contain ferromagnetic materials, will not saturate, non-invasive measurement, and has a wide measurement bandwidth range. On the other hand, due to its small cross-section, the skeleton shape can be changed according to the measured circuit such as semiconductor switches, so as to match the needs more flexibly without changing the circuit structure or wiring. Therefore, the Rogowski coil current sensor is suitable for measuring the current of power semiconductor devices such as IGBT. It can detect the rapid rise of current caused by overcurrent and short circuit inside the IGBT, thereby protecting the IGBT. Therefore, the measurement accuracy of the Rogowski coil directly affects the control accuracy and reliability of the crimped IGBT, and it is very necessary to calibrate the test accuracy of the Rogowski coil current sensor.

[0042] See also Figure 2 , Figure 2 Schematic diagram of the structure of the Rogowski coil accuracy calibration system for crimped IGBT current measurement provided by the embodiment of the present invention. Figure 1 As shown, the Rogowski coil accuracy calibration system for crimped IGBT current measurement includes a plurality of current guiding bosses connected in parallel;

[0043] Each of the flow-guiding bosses comprises a first test port, a first grounding copper busbar, a first insulator, a Rogowski coil to be calibrated, a flow-through boss, a second insulator, a second grounding copper busbar, a second test port, and a plurality of resistors connected in parallel with the second test port;

[0044] The first test port is connected to the first grounding copper busbar, which is connected to the first insulator and then to one end of the current-passing boss, the Rogowski coil to be calibrated is nested on the current-passing boss, the other end of the current-passing boss is connected to the second insulator, the second insulator is connected to the second grounding copper busbar, and the second grounding copper busbar is connected to the second test port.

[0045] It should be noted that both ends of each flow guiding boss also include BNC ports (a connector for coaxial cables), namely BNC port 1 and BNC port 2, which are used to isolate input signals to reduce mutual interference between signals.

[0046] Specifically, each of the resistors is a high-frequency non-inductive resistor.

[0047] In one embodiment, the number of resistors connected in parallel with the second test port is 10, that is, 10 high-frequency non-inductive resistors are connected in parallel with the second test port.

[0048] It is worth mentioning that several high-frequency non-inductive resistors are connected in parallel in order to reduce the influence of resistance and make the resistance value of the overall parallel resistance smaller. Because there are multiple flow-guiding bosses in parallel, in order to reduce the influence of mutual inductance between different flow-guiding bosses, non-inductive resistors should be selected when connecting resistors in parallel to avoid their influence on the experimental measurement results. Therefore, by adopting the strategy of connecting multiple resistors in parallel, the stray inductance can be further reduced and the test accuracy can be further improved. In addition, the selection of high-frequency non-inductive resistors is crucial. Compared with the traditional current acquisition method based on coaxial resistors, the use of high-frequency non-inductive resistors can not only significantly reduce equipment costs and improve the economy of the overall solution, but also in terms of power selection, it only needs to ensure that it matches the output power of the signal generator or signal amplifier to meet the test requirements.

[0049] Specifically, the plurality of parallel flow-guiding bosses are arranged in a matrix.

[0050] It is worth noting that the matrix arrangement can flexibly adjust the size and spacing of the guide bosses according to actual needs.

[0051] Preferably, the ratio of each of the flow bosses to the flow bosses inside the press-fit IGBT to be tested is 1:1.

[0052] Preferably, the structure of each of the guide bosses is consistent with the structure of the crimping boss of the crimping-type IGBT chip to be tested.

[0053] It is worth noting that the design of the current-passing boss at high frequencies also needs to consider the calculation of stray inductance, which is directly related to the accuracy of the test results. Therefore, the current-passing boss is designed to maintain a 1:1 ratio with the current-passing boss inside the actual crimp-type IGBT to be tested, which can achieve equivalent substitution, thereby ensuring a high degree of consistency between the test conditions and the actual application scenarios, thereby better simulating the state of the Rogowski coil when measuring the current of the crimp-type IGBT chip, thereby improving the accuracy of the verification.

[0054] Based on the above-mentioned Rogowski coil accuracy calibration system for crimped-type IGBT current measurement, the present invention provides an embodiment of a corresponding calibration method.

[0055] See also Figures 3-4 , Figures 3-4 : is a flow chart of a Rogowski coil accuracy calibration method for crimped IGBT current measurement provided by an embodiment of the present invention, such as Figure 3 As shown, the Rogowski coil accuracy calibration method for crimped IGBT current measurement includes steps S1 to S2:

[0056] S1, testing the transfer impedance between the first test port in each flow guide boss and the Rogowski coil to be calibrated;

[0057] S2. According to the transfer impedance between the first test port in all the flow guide bosses and the Rogowski coil to be calibrated, calibrate the anti-interference capability and test accuracy of all the Rogowski coils to be calibrated.

[0058] Specifically, Figure 4 As shown, the test of the transfer impedance between the first test port in each flow guide boss and the Rogowski coil to be calibrated includes:

[0059] S101, using a signal generator to provide a matching test resistor to the second test port, applying a voltage to the first test port, and testing the voltage of the second test port;

[0060] S102, calculating a scattering parameter between the first test port and the second test port according to an applied voltage of the first test port and a voltage of the second test port;

[0061] S103, calculating an input current of the first test port according to a scattering parameter between the first test port and the second test port;

[0062] S104, using a signal generator to provide a matching test resistor to the third test port, and testing the voltage of the third test port; wherein the third test port is formed by the Rogowski coil to be calibrated;

[0063] S105 , calculating the transfer impedance between the first test port and the Rogowski coil to be calibrated according to the input current of the first test port and the voltage of the third test port.

[0064] Specifically, the scattering parameter between the first test port and the second test port is calculated by the following formula:

[0065]

[0066] Wherein, U1 is the applied voltage of the first test port; U2 is the voltage of the second test port.

[0067] Specifically, the input current of the first test port is calculated by the following formula:

[0068]

[0069] Wherein, R is the resistance value of a plurality of resistors connected in parallel with the second test port; and R2 is the resistance value given to the second test port for matching test.

[0070] Specifically, the transfer impedance between the first test port and the Rogowski coil to be calibrated is calculated by the following formula:

[0071]

[0072] Wherein, U3 is the voltage of the third test port.

[0073] For example, taking a single flow-guiding boss as an example, the transfer impedance parameter between the first test port and the third test port formed by the Rogowski coil to be calibrated is taken as the measurement target. With the help of a signal generator, a 50-ohm matching test resistor is first applied to the second test port to test the scattering parameter between the first test port and the second test port. Then, a unit voltage is applied to the first test port to test the voltage of the second test port. Based on formula (1), the input current of the first test port can be obtained. In order to enhance the input current, a high-frequency non-inductive small resistor R is connected in parallel at the second test port.

[0074]

[0075] Then, a 50 ohm matching test resistor is given to the third test port, and the scattering parameters between the first test port and the third test port are tested to obtain the frequency characteristics of the transfer impedance between the first test port and the third test port, that is:

[0076]

[0077] Based on the same principle, it is necessary to test the transfer impedance between all parallel input first test ports and all parallel chip current test Rogowski coils of all crimped IGBTs to form a transfer impedance matrix Z Γ , in order to calibrate the anti-interference ability and test accuracy of the matrix Rogowski coil.

[0078]

[0079] It is worth noting that the embodiment of the present invention proposes an innovative testing method, which can realize the testing process by only using a signal generator, without the need for an additional network analyzer, thereby greatly simplifying the testing steps and improving the convenience of the test. Compared with the traditional testing method that relies on a network analyzer, this solution has the ability to test large currents. This feature is particularly critical for overcoming the limitation of the small mutual inductance between the tested flow-conducting boss and the Rogowski coil, and can effectively improve the accuracy of the test. In addition, by introducing a customized simulated flow-through boss, the transfer impedance characteristics of the tested crimped IGBT parallel chip boss can be accurately reproduced at a ratio of 1:1, ensuring the accuracy and high reliability of the crimped IGBT current test results. The embodiment of the present invention not only achieves optimization in the process, but also enhances the testing capability, providing technical support for research and testing work in related fields.

[0080] In summary, the embodiment of the present invention provides a Rogowski coil accuracy calibration method for crimped IGBT current measurement, which is implemented by measuring the transfer impedance between several guide bosses and Rogowski coils. First, a signal generator is used to apply voltage to the first test port, and the voltage of the second test port is measured. The scattering parameters are calculated according to the voltages of the first and second test ports, and the input current of the first test port is calculated according to the scattering parameters. Then, a signal generator is used to measure the voltage of the third test port (Rogowski coil), and the transfer impedance is calculated according to the input current and the voltage of the third test port. Finally, the transfer impedance data between the first test port and the Rogowski coil in all guide bosses are analyzed to evaluate the anti-interference ability and test accuracy of the Rogowski coil, and ensure the reliability of the crimped IGBT current measurement results.

[0081] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A Rogowski coil accuracy calibration system for crimped IGBT current measurement, characterized in that: It includes a plurality of flow guide bosses connected in parallel; Each of the flow-guiding bosses comprises a first test port, a first grounding copper busbar, a first insulator, a Rogowski coil to be calibrated, a flow-through boss, a second insulator, a second grounding copper busbar, a second test port, and a plurality of resistors connected in parallel with the second test port; The first test port is connected to the first grounding copper busbar, which is connected to the first insulator and then to one end of the current-passing boss, the Rogowski coil to be calibrated is nested on the current-passing boss, the other end of the current-passing boss is connected to the second insulator, the second insulator is connected to the second grounding copper busbar, and the second grounding copper busbar is connected to the second test port.

2. The Rogowski coil accuracy calibration system for crimped IGBT current measurement according to claim 1, characterized in that: The plurality of parallel flow-guiding bosses are arranged in a matrix.

3. The Rogowski coil accuracy calibration system for crimped IGBT current measurement according to claim 1, characterized in that: Each of the resistors is a high frequency non-inductive resistor.

4. The Rogowski coil accuracy calibration system for crimped IGBT current measurement according to claim 1, characterized in that: The ratio of each of the flow bosses to the flow bosses inside the press-fit IGBT to be tested is 1:

1.

5. The Rogowski coil accuracy calibration system for crimped IGBT current measurement according to claim 1, characterized in that: The structure of each of the guide bosses is consistent with the structure of the crimping boss of the crimping-type IGBT chip to be tested.

6. A Rogowski coil accuracy calibration method for crimped IGBT current measurement, characterized in that: A Rogowski coil accuracy calibration system for crimped IGBT current measurement as claimed in any one of claims 1 to 5, comprising: Testing the transfer impedance between the first test port in each flow guide boss and the Rogowski coil to be calibrated; According to the transfer impedance between the first test port in all the flow guide bosses and the Rogowski coil to be calibrated, the anti-interference capability and the test accuracy of all the Rogowski coils to be calibrated are calibrated.

7. The Rogowski coil accuracy calibration method for crimped IGBT current measurement according to claim 6, characterized in that: The testing of the transfer impedance between the first test port in each flow guiding boss and the Rogowski coil to be calibrated comprises: Using a signal generator, providing a matching test resistor to the second test port, applying a voltage to the first test port, and testing the voltage of the second test port; calculating a scattering parameter between the first test port and the second test port according to an applied voltage at the first test port and a voltage at the second test port; Calculating an input current of the first test port according to a scattering parameter between the first test port and the second test port; A signal generator is used to provide a matching test resistor to the third test port, and the voltage of the third test port is tested; wherein the third test port is formed by the Rogowski coil to be calibrated; The transfer impedance between the first test port and the Rogowski coil to be calibrated is calculated according to the input current of the first test port and the voltage of the third test port.

8. The Rogowski coil accuracy calibration method for crimped IGBT current measurement according to claim 7, characterized in that: The scattering parameter between the first test port and the second test port is calculated by the following formula: Wherein, U1 is the applied voltage of the first test port; U2 is the voltage of the second test port.

9. The Rogowski coil accuracy calibration method for crimped IGBT current measurement according to claim 8, characterized in that: The input current of the first test port is calculated by the following formula: Wherein, R is the resistance value of a plurality of resistors connected in parallel with the second test port; and R2 is the resistance value given to the second test port for matching test.

10. The Rogowski coil accuracy calibration method for crimped IGBT current measurement according to claim 9, characterized in that: The transfer impedance between the first test port and the Rogowski coil to be calibrated is calculated by the following formula: Wherein, U3 is the voltage of the third test port.

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