IGBT device internal current sensing method and device based on Z-axis magnetic field measurement

Abstract

The invention provides an IGBT device internal current sensing method and device based on Z-axis magnetic field measurement, and relates to the technical field of electrical engineering.The method comprises the steps that a short coil array is arranged on the surface of a to-be-measured crimping type IGBT device, and the short coil array comprises a plurality of short coils arranged in an array in the Z-axis direction; connecting the two ends of each short coil with an integrator circuit; measuring the induced electromotive force generated by the two ends of each short coil in the Z-axis direction; the measured induced electromotive force generated at the two ends of each short coil is converted into current distribution change near the short coil through an integrator circuit connected with the two ends of each short coil; and analyzing the current distribution state of the chip in the device based on the current distribution change near the short coil. The current distribution in the device can be accurately measured and sensed, whether an overheated chip area exists in the device or not can be accurately judged, intervention is carried out in time, safety early warning is achieved, and the service life of the device is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of electrical engineering technology, and in particular to a method and device for sensing the internal current of an IGBT device based on Z-axis magnetic field measurement. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) modules, at the heart of the power electronics industry, are widely used in power equipment, renewable energy systems, and electric vehicles due to their high reliability, high current capacity, and cost-effectiveness. However, IGBT modules are susceptible to damage from dynamic loads, such as high current and voltage conditions. Therefore, health profiling of IGBT modules is crucial to improve their reliability, lifespan, and intelligence.

[0003] In the related art, due to the unique packaging mode of the press-fit IGBT device, multiple chips inside are densely arranged in parallel, forming a closed electrical, thermal, and force multi-physical field coupling environment, which can easily lead to uneven current distribution inside the press-fit IGBT device, affecting the reliability of the press-fit IGBT device. Especially when the press-fit IGBT device has more than one chip damaged position causing current unevenness, simply measuring the current eccentric point will produce a large error in locating the chip damage position inside the press-fit IGBT device. It is impossible to deeply understand the current distribution inside the press-fit IGBT device, and it is impossible to accurately judge whether the heat inside the press-fit IGBT device is uniform and whether there is a potential risk of short-circuit failure. Measures cannot be taken in time to intervene, resulting in the occurrence of serious faults such as short circuits.

[0004] In view of this, there is an urgent need to provide a method for measuring the internal current distribution of a press-fit IGBT device to solve the problems of the related art. Summary of the Invention

[0005] In response to the problems existing in the related technologies, the present invention provides a method and device for sensing the internal current of an IGBT device based on Z-axis magnetic field measurement. The method and device can monitor the current distribution of the key characteristic quantity that is most likely to cause the press-fit IGBT device to malfunction during its operation, perform status monitoring of the press-fit IGBT device in real time, and gain an in-depth understanding of the internal current distribution of the press-fit IGBT device. In particular, when multiple chip damage locations of the press-fit IGBT device cause uneven current inside the press-fit IGBT device, the method and device can accurately grasp the internal current distribution of the press-fit IGBT device, accurately judge whether the internal heating of the press-fit IGBT device is uniform, and whether there is a potential risk of short-circuit failure. The chip area that may overheat due to thermal stress concentration can be monitored in advance, so that timely intervention measures can be taken to avoid the occurrence of serious faults such as short circuits, achieve safety warnings, and improve the operating life of the device.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement, the method comprising: A short coil array is arranged on the surface of the press-fit IGBT device to be tested, wherein the short coil array includes a plurality of short coils arranged in an array in the Z-axis direction; connecting both ends of each short coil to an integrator circuit; Measuring the induced electromotive force generated at both ends of each short coil in the Z-axis direction; The integrator circuit connected to both ends of each short coil converts the measured induced electromotive force generated at both ends of each short coil into a change in current distribution near the short coil; Based on the current distribution change near the short coil, the current distribution state of the internal chip of the press-fit IGBT device to be tested is analyzed to obtain an analysis result.

[0007] In some embodiments, connecting both ends of each short coil to an integrator circuit comprises: Connecting the lower ports of each short coil in parallel via a negative electrode connecting wire to obtain a negative electrode external port; Leading out a positive electrode connecting wire from the upper port of each short coil to obtain a positive electrode external connection port of each short coil; The negative external port and the positive external port of each short coil are connected to the integrator circuit.

[0008] In some embodiments, the method further comprises: Determining the port position of the positive external port corresponding to each short coil according to the coil position of each short coil; Each of the positive electrode external connection ports is arranged according to its corresponding port position.

[0009] In some embodiments, converting the measured induced electromotive force generated at both ends of each short coil into a change in current distribution near the short coil by the integrator circuit connected to both ends of each short coil comprises: The integrator circuit connected to both ends of each short coil converts the measured induced electromotive force generated at both ends of each short coil in the Z-axis direction into current distribution changes of the short coil at different positions in the Z-axis direction; When the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis, and when the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis, it is determined that the current of the internal chip of the press-fit IGBT device to be tested is in a current-equalizing distribution state; When the output current of the short coils at different positions along the Z axis is asymmetric along the Z axis, or when the output current of the short coils at different positions along the Z axis is asymmetric along the Z axis, it is determined that the current distribution of the internal chip of the press-fit IGBT device to be tested is uneven.

[0010] In some embodiments, based on the current distribution change near the short coil, the current distribution state of the internal chip of the press-fit IGBT device to be tested is analyzed to obtain the analysis result, including: When the output current of the short coil at a certain position along the Z axis is greater than or equal to a preset output current threshold, it is determined that a short circuit fault occurs in the chip corresponding to the position of the short coil inside the tested press-fit IGBT device, and the current of the chip is too large. In addition, it is determined that the output current at the position of the symmetrical coil symmetrical to the short coil at a certain position along the Z axis is too small. When the output current of the short coil at a certain position along the Z-axis is less than a preset output current threshold, it is determined that the current of the chip corresponding to the position of the short coil inside the press-fit IGBT device to be tested is too small, and it is determined that the output current of the symmetrical coil symmetrical to the short coil at a certain position along the Z-axis is too large.

[0011] In a second aspect, the present invention provides an IGBT device internal current sensing device based on Z-axis magnetic field measurement, the device comprising: The coil setting unit is configured to set a short coil array on the surface of the press-fit IGBT device to be tested, wherein the short coil array includes a plurality of short coils arranged in an array in the Z-axis direction; a connecting unit configured to connect both ends of each of the short coils to an integrator circuit; A measuring unit configured to measure the induced electromotive force generated at both ends of each short coil in the Z-axis direction; a conversion unit configured to convert the measured induced electromotive force generated at both ends of each short coil into a change in current distribution near the short coil via the integrator circuit connected to both ends of each short coil; The circuit analysis unit is configured to analyze the current distribution state of the internal chip of the press-fit IGBT device to be tested based on the current distribution change near the short coil to obtain an analysis result.

[0012] In some embodiments, the connecting unit includes: a lower port connection module configured to connect the lower ports of each of the short coils in parallel via a negative electrode connection wire to obtain a negative electrode external connection port; an upper port connection module configured to lead out a positive connection wire from the upper port of each short coil to obtain a positive external connection port of each short coil; The positive and negative electrode connection module is configured to connect the negative electrode external connection port and the positive electrode external connection port of each short coil to the integrator circuit.

[0013] In some embodiments, the apparatus further comprises: a port position determining unit configured to determine the port position of the positive external port corresponding to each short coil according to the coil position of each short coil; The port setting unit is configured to arrange and set each of the positive external ports according to its corresponding port position.

[0014] In some embodiments, the conversion unit includes: a potential energy conversion module configured to convert the measured induced electromotive force generated at both ends of each short coil in the Z-axis direction into current distribution changes of the short coil at different positions in the Z-axis direction through the integrator circuit connected to both ends of each short coil; a current distribution confirmation module configured to determine that the current of the internal chip of the press-fit IGBT device to be tested is in a current distribution state when the output currents of the short coils at different positions on the Z axis are symmetrical along the Z axis, and when the output currents of the short coils at different positions on the Z axis are symmetrical along the Z axis; The current uneven distribution module is configured to determine that the current distribution of the internal chip of the press-fit IGBT device to be tested is uneven when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis, or when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis.

[0015] In some embodiments, the circuit analysis unit includes: The first analysis module is configured to determine that a short circuit fault occurs in a chip corresponding to the position of the short coil in the tested press-fit IGBT device and the current of the chip is too high when the output current of the short coil at a certain position in the Z-axis is greater than or equal to a preset output current threshold, and that the output current of a symmetrical coil symmetrical to the short coil at a certain position in the Z-axis is too low; The second analysis module is configured to determine that the current of the chip corresponding to the position of the short coil inside the press-fit IGBT device to be tested is too small when the output current of the short coil at a certain position in the Z-axis is less than a preset output current threshold, and to determine that the output current of the position of the symmetrical coil symmetrical to the short coil at a certain position in the Z-axis is too large.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method and device for sensing the internal current of an IGBT device based on Z-axis magnetic field measurement. The method and device can monitor the current distribution of a key characteristic quantity that is most likely to cause a press-fit IGBT device to malfunction during its operation, can perform status monitoring of the press-fit IGBT device in real time, and can provide an in-depth understanding of the internal current distribution of the press-fit IGBT device. In particular, when multiple chip damage locations of the press-fit IGBT device cause uneven current inside the press-fit IGBT device, the method and device can accurately grasp the internal current distribution of the press-fit IGBT device, can accurately judge whether the internal heating of the press-fit IGBT device is uniform and whether there is a potential risk of short-circuit failure, can monitor in advance the chip area that may overheat due to concentrated thermal stress, so as to take timely intervention measures to avoid the occurrence of serious faults such as short circuits, realize safety warnings, and improve the operating life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of a method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement provided in an embodiment of the present disclosure; Figure 2 A global schematic diagram of a short coil array provided on the upper surface of a press-fit IGBT device according to an embodiment of the present disclosure; Figure 3 A schematic structural diagram of a single short coil provided in an embodiment of the present disclosure; Figure 4 A schematic diagram of the external circuit connection of the short coil array provided in an embodiment of the present disclosure; Figure 5 A side view of a short coil array provided in an embodiment of the present disclosure on an XZ plane; Figure 6A schematic structural diagram of an IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure; Figure 7 A schematic structural diagram of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure; Figure 8 A schematic structural diagram of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure; Figure 9 A schematic diagram of the structure of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] It is worth noting that the methods used in the present invention are all conventional methods unless otherwise specified; the raw materials and devices used are all conventional commercially available products, and their sources are not specifically limited unless otherwise specified.

[0019] See also Figure 1 , Figure 1 A flow chart of a method for sensing the internal current of an IGBT device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure is provided. The method for sensing the internal current of an IGBT device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure includes the following steps: S101 , setting a short coil array on the surface of a press-fit IGBT device 1 to be tested, wherein the short coil array includes a plurality of short coils 2 arranged in an array in the Z-axis direction.

[0020] See also Figure 2 , Figure 2 A global schematic diagram of a short coil array provided on the upper surface of a press-fit IGBT device is provided in an embodiment of the present disclosure. The embodiment of the present disclosure uses an annular coil (i.e., short coil 2) along the Z-axis direction to form the short coil array. For example, four rows and four columns of 16 annular coils (i.e., short coil 2) are used, and the short coil array composed of these 16 annular coils is arranged on the upper surface of the press-fit IGBT device 1. The arrangement position of the short coil array is almost close to the upper surface of the press-fit IGBT device 1.

[0021] It should be noted that users can set ring coils of different radii and short coil arrays with different spacing distances according to actual business needs. In addition, users can change the arrangement of the short coil array according to actual business needs. For example, the arrangement in the Z and Y axial directions can be modified to a circle-by-circle arrangement in the form of polar coordinates. In this way, current sensing devices with different measurement accuracies can be formed, which are suitable for actual working conditions with different specifications and different measurement requirements.

[0022] S102 , connecting the two ends of each short coil 2 to an integrator circuit.

[0023] See also Figure 3 , Figure 3 This is a structural schematic diagram of a single short coil provided in an embodiment of the present disclosure. In an embodiment of the present disclosure, an integrator circuit is connected to both ends of the short coil 2 to convert the induced electromotive force generated at both ends of each short coil in the Z-axis direction measured by the short coil 2 into a change in the current distribution of the short coil 2 at different positions in the Z-axis direction. Such an arrangement can measure the magnetic field in the Z-axis direction, thereby measuring the current distribution inside the crimped IGBT device 1.

[0024] S103 , measuring the induced electromotive force generated at both ends of each short coil 2 in the Z-axis direction.

[0025] S104 , converting the measured induced electromotive force generated at both ends of each short coil 2 into a change in current distribution near the short coil through the integrator circuit connected to both ends of each short coil 2 .

[0026] S105 , based on the current distribution change near the short coil 2 , analyze the current distribution state of the internal chip of the press-fit IGBT device 1 to be tested to obtain an analysis result.

[0027] The present invention provides an internal current sensing method for an IGBT device based on Z-axis magnetic field measurement. The method can monitor the current distribution of a key characteristic quantity that is most likely to cause the press-fit IGBT device 1 to malfunction during its operation, perform status monitoring on the press-fit IGBT device 1 in real time, and gain an in-depth understanding of the internal current distribution of the press-fit IGBT device 1. In particular, when multiple chip damage positions of the press-fit IGBT device 1 cause uneven current inside the press-fit IGBT device 1, the method can accurately grasp the internal current distribution of the press-fit IGBT device 1, accurately judge whether the internal heating of the press-fit IGBT device 1 is uniform, and whether there is a potential risk of short-circuit failure. The method can monitor in advance the chip area that may overheat due to concentrated thermal stress, so as to take timely intervention measures to avoid the occurrence of serious faults such as short circuits, realize safety warnings, and improve the operating life of the device.

[0028] In some embodiments, connecting both ends of each short coil 2 to an integrator circuit includes: Connect the lower ports of each short coil 2 in parallel via a negative electrode connecting wire to obtain a negative electrode external port; Lead out a positive electrode connecting wire from the upper port of each short coil 2 to obtain a positive electrode external connection port of each short coil 2; The negative external port and the positive external port of each short coil 2 are connected to the integrator circuit.

[0029] In some embodiments, the method further comprises: Determine the port position of the positive external port corresponding to each short coil 2 according to the coil position of each short coil 2; Each of the positive electrode external connection ports is arranged according to its corresponding port position.

[0030] See also Figure 4 , Figure 4 This is a schematic diagram of the external circuit connection of the short coil array provided in an embodiment of the present disclosure. Figure 4 In the figure, the solid line represents the negative connection wire. Connect the lower ports of all short coils 2 in parallel using the negative connection wire to form a negative external port. The black solid origin in the figure represents the negative external port. Lead out the wire from the upper port of each short coil separately ( Figure 4 The circuit diagram depicts a single positive external connection port (indicated by a dotted line in the figure), with each positive external connection port aligned with the coil position of a short coil 2. This arrangement allows for the measurement of current near any short coil 2 at any time. Each short coil 2 is connected to an independent external circuit connection line, and the external circuit connection ports are aligned with the location of the short coil 2, allowing for clear measurement of current changes at that location.

[0031] See also Figure 5 , Figure 5 A side view of the short coil array provided in an embodiment of the present disclosure on the XZ plane, Figure 5 The upper middle layer represents the short coil array (including several short coils 2), while the lower layer represents the press-fit IGBT device 1. The short coil array is placed almost directly against the top surface of the press-fit IGBT device, occupying very little height and resembling a very thin gasket. During actual measurement, the short coil array only needs to be installed before the press-fit IGBT device 1 is press-fitted. Compared to the entire press-fit structure, the short coil array is very thin and does not occupy a large amount of space.

[0032] In some embodiments, the integrator circuit connected to both ends of each short coil 2 converts the measured induced electromotive force generated at both ends of each short coil 2 into a change in current distribution near the short coil 2, including: The integrator circuit connected to both ends of each short coil 2 converts the measured induced electromotive force generated at both ends of each short coil 2 in the Z-axis direction into current distribution changes of the short coil 2 at different positions in the Z-axis direction; When the output currents of the short coils 2 at different positions along the Z axis are symmetrical along the Z axis, and when the output currents of the short coils 2 at different positions along the Z axis are symmetrical along the Z axis, it is determined that the current of the internal chip of the press-fit IGBT device 1 to be tested is in a current-equalizing distribution state; When the output current of the short coil 2 at different positions on the Z axis is asymmetric along the Z axis, or when the output current of the short coil 2 at different positions on the Z axis is asymmetric along the Z axis, it is determined that the current distribution of the chip inside the press-fit IGBT device 1 to be tested is uneven.

[0033] In some embodiments, based on the current distribution change near the short coil 2 , the current distribution state of the chip inside the press-fit IGBT device 1 to be tested is analyzed to obtain analysis results, including: When the output current of the short coil 2 at a certain position in the Z-axis is greater than or equal to a preset output current threshold, it is determined that a short circuit fault occurs in the chip corresponding to the position of the short coil 2 inside the tested press-fit IGBT device 1, and the current of the chip is too large. In addition, it is determined that the output current at the position of the symmetrical coil symmetrical to the short coil 2 at a certain position in the Z-axis is too small. When the output current of the short coil 2 at a certain position along the Z-axis is less than a preset output current threshold, it is determined that the current of the chip corresponding to the position of the short coil 2 inside the press-fit IGBT device 1 to be tested is too small, and it is determined that the output current of the symmetrical coil symmetrical to the short coil 2 at a certain position along the Z-axis is too large.

[0034] Optionally, when the internal current of the press-fit IGBT device 1 is evenly distributed, the magnetic field generated is basically evenly distributed, so the current distribution measured using the short coil array will basically reflect a uniform distribution, and the magnitude of the magnetic field is proportional to the magnitude of the current and inversely proportional to the measurement distance. Therefore, when a chip at a certain location in the press-fit IGBT device 1 has a short-circuit fault trend, the current of the chip increases, and the current measured by the short coil 2 at the nearest position will also increase accordingly.

[0035] The disclosed embodiments can accurately monitor the current distribution within a press-fit IGBT device 1, allowing for early detection of chip regions that may overheat due to concentrated thermal stress, allowing for timely intervention to prevent serious faults such as short circuits. This not only allows for intuitive observation of the health status of the press-fit IGBT device 1 but also serves as a key characteristic parameter for assessing the aging of the press-fit IGBT device 1, enabling precise status monitoring of the press-fit IGBT device 1 and ensuring its safe, reliable, and efficient operation under various complex operating conditions.

[0036] See also Figure 6 , Figure 6This is a schematic diagram of the structure of an IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure. The present disclosure provides an IGBT device internal current sensing device based on Z-axis magnetic field measurement, the device comprising: The coil setting unit 61 is configured to set a short coil array on the surface of the press-fit IGBT device to be tested, wherein the short coil array includes a plurality of short coils arranged in an array in the Z-axis direction; a connecting unit 62 configured to connect both ends of each of the short coils to an integrator circuit; The measuring unit 63 is configured to measure the induced electromotive force generated at both ends of each short coil in the Z-axis direction; The conversion unit 64 is configured to convert the measured induced electromotive force generated at both ends of each short coil into a current distribution change near the short coil through the integrator circuit connected to both ends of each short coil; The circuit analysis unit 65 is configured to analyze the current distribution state of the internal chip of the press-fit IGBT device to be tested based on the current distribution change near the short coil to obtain an analysis result.

[0037] See also Figure 7 , Figure 7 This is a schematic diagram of the structure of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure. In some embodiments, the connecting unit 62 includes: The lower port connection module 621 is configured to connect the lower ports of each short coil in parallel via a negative electrode connection wire to obtain a negative electrode external connection port; The upper port connection module 622 is configured to lead out a positive connection wire from the upper port of each short coil to obtain a positive external connection port of each short coil; The positive and negative connection module 623 is configured to connect the negative external port and the positive external port of each short coil to the integrator circuit.

[0038] In some embodiments, the apparatus further comprises: a port position determining unit configured to determine the port position of the positive external port corresponding to each short coil according to the coil position of each short coil; The port setting unit is configured to arrange and set each of the positive external ports according to its corresponding port position.

[0039] See also Figure 8 , Figure 8This is a schematic diagram of the structure of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure. In some embodiments, the conversion unit 64 includes: The potential energy conversion module 641 is configured to convert the measured induced electromotive force generated at both ends of each short coil in the Z-axis direction into current distribution changes of the short coil at different positions in the Z-axis direction through the integrator circuit connected to both ends of each short coil; The current distribution confirmation module 642 is configured to determine that the current of the internal chip of the press-fit IGBT device to be tested is in a current distribution state when the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis, and when the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis; The current uneven distribution module 643 is configured to determine that the current distribution of the internal chip of the press-fit IGBT device to be tested is uneven when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis, or when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis.

[0040] See also Figure 9 , Figure 9 This is a schematic diagram of the structure of another IGBT device internal current sensing device based on Z-axis magnetic field measurement provided by an embodiment of the present disclosure. In some embodiments, the circuit analysis unit 65 includes: The first analysis module 651 is configured to, when the output current of the short coil at a certain position along the Z-axis is greater than or equal to a preset output current threshold, determine that a short circuit fault occurs in the chip corresponding to the position of the short coil within the tested press-fit IGBT device, and that the current of the chip is too high; and determine that the output current of a symmetrical coil symmetrical to the short coil at a certain position along the Z-axis is too low; The second analysis module 652 is configured to determine that the current of the chip corresponding to the position of the short coil inside the tested press-fit IGBT device is too small when the output current of the short coil at a certain position in the Z-axis is less than a preset output current threshold, and to determine that the output current of the symmetrical coil symmetrical to the short coil at a certain position in the Z-axis is too large.

[0041] The disclosed embodiments are aimed at press-fit IGBT devices, one of the key components in the field of flexible direct current transmission. In order to sense the current distribution of the press-fit IGBT device during operation, an internal current sensing device for the IGBT device based on Z-axis magnetic field measurement is designed. This device can monitor the current distribution of the key characteristic quantity that is most likely to cause failure of the press-fit IGBT device during operation, perform real-time status monitoring, implement safety warnings, and improve the operating life of the device.

[0042] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement, characterized in that: The method comprises: A short coil array is arranged on the surface of the press-fit IGBT device to be tested, wherein the short coil array includes a plurality of short coils arranged in an array in the Z-axis direction; connecting both ends of each short coil to an integrator circuit; Measuring the induced electromotive force generated at both ends of each short coil in the Z-axis direction; The integrator circuit connected to both ends of each short coil converts the measured induced electromotive force generated at both ends of each short coil into a change in current distribution near the short coil; Based on the current distribution change near the short coil, the current distribution state of the internal chip of the press-fit IGBT device to be tested is analyzed to obtain an analysis result.

2. The method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement according to claim 1, characterized in that: Connect both ends of each short coil to an integrator circuit, comprising: Connecting the lower ports of each short coil in parallel via a negative electrode connecting wire to obtain a negative electrode external port; Leading out a positive electrode connecting wire from the upper port of each short coil to obtain a positive electrode external connection port of each short coil; The negative external port and the positive external port of each short coil are connected to the integrator circuit.

3. The method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement according to claim 2, characterized in that: The method further comprises: Determining the port position of the positive external port corresponding to each short coil according to the coil position of each short coil; Each of the positive electrode external connection ports is arranged according to its corresponding port position.

4. The method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement according to claim 1, characterized in that: The integrator circuit connected to both ends of each short coil converts the measured induced electromotive force generated at both ends of each short coil into a current distribution change near the short coil, including: The integrator circuit connected to both ends of each short coil converts the measured induced electromotive force generated at both ends of each short coil in the Z-axis direction into current distribution changes of the short coil at different positions in the Z-axis direction; When the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis, and when the output currents of the short coils at different positions along the Z axis are symmetrical along the Z axis, it is determined that the current of the internal chip of the press-fit IGBT device to be tested is in a current-equalizing distribution state; When the output current of the short coils at different positions along the Z axis is asymmetric along the Z axis, or when the output current of the short coils at different positions along the Z axis is asymmetric along the Z axis, it is determined that the current distribution of the internal chip of the press-fit IGBT device to be tested is uneven.

5. The method for sensing internal current of an IGBT device based on Z-axis magnetic field measurement according to claim 4, characterized in that: Based on the current distribution change near the short coil, the current distribution state of the chip inside the press-fit IGBT device to be tested is analyzed to obtain analysis results, including: When the output current of the short coil at a certain position along the Z axis is greater than or equal to a preset output current threshold, it is determined that a short circuit fault occurs in the chip corresponding to the position of the short coil inside the tested press-fit IGBT device, and the current of the chip is too large. In addition, it is determined that the output current at the position of the symmetrical coil symmetrical to the short coil at a certain position along the Z axis is too small. When the output current of the short coil at a certain position along the Z-axis is less than a preset output current threshold, it is determined that the current of the chip corresponding to the position of the short coil inside the press-fit IGBT device to be tested is too small, and it is determined that the output current of the symmetrical coil symmetrical to the short coil at a certain position along the Z-axis is too large.

6. An IGBT device internal current sensing device based on Z-axis magnetic field measurement, characterized in that: The device comprises: The coil setting unit is configured to set a short coil array on the surface of the press-fit IGBT device to be tested, wherein the short coil array includes a plurality of short coils arranged in an array in the Z-axis direction; a connecting unit configured to connect both ends of each of the short coils to an integrator circuit; A measuring unit configured to measure the induced electromotive force generated at both ends of each short coil in the Z-axis direction; a conversion unit configured to convert the measured induced electromotive force generated at both ends of each short coil into a change in current distribution near the short coil via the integrator circuit connected to both ends of each short coil; The circuit analysis unit is configured to analyze the current distribution state of the internal chip of the press-fit IGBT device to be tested based on the current distribution change near the short coil to obtain an analysis result.

7. The IGBT device internal current sensing device based on Z-axis magnetic field measurement according to claim 6, characterized in that: The connecting unit includes: a lower port connection module configured to connect the lower ports of each of the short coils in parallel via a negative electrode connection wire to obtain a negative electrode external connection port; an upper port connection module configured to lead out a positive connection wire from the upper port of each short coil to obtain a positive external connection port of each short coil; The positive and negative electrode connection module is configured to connect the negative electrode external connection port and the positive electrode external connection port of each short coil to the integrator circuit.

8. The IGBT device internal current sensing device based on Z-axis magnetic field measurement according to claim 7, characterized in that: The device further comprises: a port position determining unit configured to determine the port position of the positive external port corresponding to each short coil according to the coil position of each short coil; The port setting unit is configured to arrange and set each of the positive external ports according to its corresponding port position.

9. The IGBT device internal current sensing device based on Z-axis magnetic field measurement according to claim 6, characterized in that: The conversion unit includes: a potential energy conversion module configured to convert the measured induced electromotive force generated at both ends of each short coil in the Z-axis direction into current distribution changes of the short coil at different positions in the Z-axis direction through the integrator circuit connected to both ends of each short coil; a current distribution confirmation module configured to determine that the current of the internal chip of the press-fit IGBT device to be tested is in a current distribution state when the output currents of the short coils at different positions on the Z axis are symmetrical along the Z axis, and when the output currents of the short coils at different positions on the Z axis are symmetrical along the Z axis; The current uneven distribution module is configured to determine that the current distribution of the internal chip of the press-fit IGBT device to be tested is uneven when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis, or when the output current of the short coil at different positions on the Z axis is asymmetric along the Z axis.

10. The IGBT device internal current sensing device based on Z-axis magnetic field measurement according to claim 9, characterized in that: The circuit analysis unit includes: The first analysis module is configured to determine that a short circuit fault occurs in a chip corresponding to the position of the short coil in the tested press-fit IGBT device and the current of the chip is too high when the output current of the short coil at a certain position in the Z-axis is greater than or equal to a preset output current threshold, and that the output current of a symmetrical coil symmetrical to the short coil at a certain position in the Z-axis is too low; The second analysis module is configured to determine that the current of the chip corresponding to the position of the short coil inside the press-fit IGBT device to be tested is too small when the output current of the short coil at a certain position in the Z-axis is less than a preset output current threshold, and to determine that the output current of the position of the symmetrical coil symmetrical to the short coil at a certain position in the Z-axis is too large.

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