A method and circuit for testing an igbt circuit system

Abstract

This invention relates to a testing method for an IGBT circuit system, comprising the following steps: applying a pulse signal to a single IGBT transistor; obtaining the current waveform in the overall circuit using a current probe; obtaining the voltage waveforms at locations V1, V2, and V3 of each component using a voltage probe; testing the stray inductance of the bus power supply; testing the stray inductance of the multilayer copper busbar; and testing the total stray inductance of the IGBT module under test. The advantages of this invention are: it can measure the bus capacitance, multilayer copper busbar, and total stray inductance of the IGBT module separately.

Description

Technical Field

[0001] This invention relates to the field of circuit testing technology, and in particular to a testing method and circuit for an IGBT circuit system. Background Technology

[0002] Currently, the development of new energy electric vehicles is rapid. The motor controller is the control and power center of new energy vehicles, while the IGBT is the power output unit of the motor controller. Ensuring the efficient and safe operation of the entire motor controller system can save energy and improve the overall vehicle system efficiency. The drive module in the motor controller, including the drive circuit and the IGBT module, has a significant impact on the overall vehicle efficiency in actual use. The smaller the stray inductance of the entire circuit of the drive circuit and IGBT module, the smaller the voltage spike generated when the motor controller's PWM control is turned off, and the safer the drive module will be. Therefore, it is necessary to evaluate the stray inductance of the entire circuit and the stray inductance of each component, including the bus capacitor, the multilayer copper busbar, and the internal stray inductance of the IGBT module.

[0003] The currently widely used dual-pulse test circuits can test the stray inductance of the entire drive circuit, but cannot test the stray inductance of the bus capacitor, the multilayer copper busbar, or the total stray inductance of the IGBT module separately.

[0004] Therefore, there is an urgent need to provide a method that can separately measure the bus capacitance and the total stray inductance of the multilayer copper IGBT module, so as to facilitate the evaluation of whether the circuit design of the drive module system meets the requirements. Summary of the Invention

[0005] This invention provides a testing method and circuit for IGBT circuit systems, which can solve problems in related technologies.

[0006] On the one hand, embodiments of the present invention provide a testing method for an IGBT circuit system.

[0007] Includes the following steps:

[0008] S10. Apply a pulse signal to a single IGBT transistor;

[0009] S20. Obtain the current waveform in the total circuit using a current probe;

[0010] S30. Obtain the voltage waveforms at positions V1, V2, and V3 of each component using voltage probes;

[0011] S40. Test the stray inductance of the bus power supply;

[0012] S50. Test stray inductance of multilayer copper busbars;

[0013] S60. Test the total stray inductance of the IGBT module under test.

[0014] In some embodiments, S40. testing the stray inductance of the bus power supply includes the following steps:

[0015] S41. Measure the voltage waveform across the stray inductance of the bus power supply using the first voltage probe;

[0016] S42. Calculate the value of the stray inductance of the bus power supply based on the captured voltage and current waveform signals at the turn-off moment.

[0017] In some embodiments, S50. Testing the stray inductance of the multilayer copper busbar includes the following steps:

[0018] S51. Measure the voltage waveform across the stray inductance of the multilayer copper busbar using the second voltage probe;

[0019] S52. Calculate the stray inductance value of the multilayer copper busbar based on the captured voltage and current waveform signals at the turn-off moment.

[0020] In some embodiments, S60. Testing the total stray inductance of the IGBT module includes the following steps:

[0021] S61. Measure the voltage waveforms across the positive and negative copper busbars of the IGBT module under test using the third voltage probe;

[0022] S62. Calculate the total stray inductance of the IGBT module under test based on the captured voltage and current waveform signals at the turn-off moment.

[0023] In some embodiments, the stray inductance value is calculated as follows:

[0024] L=Δu / (di / dt),

[0025] Where L is the stray inductance value, Δu is the voltage value of the stray inductance, di is the current value in the total circuit, and di / dt is the rate of change of the current in the total circuit.

[0026] On the one hand, an IGBT circuit system test circuit is provided, including the test circuit required by the IGBT circuit system test method described in any one of the above.

[0027] In some embodiments, the system includes a bus power stray inductor, a multilayer power stray inductor, and an IGBT module under test. The negative terminal of the bus power stray inductor is connected to the positive terminal of the multilayer copper bus stray inductor, and the negative terminal of the multilayer copper bus stray inductor is connected to the positive terminal of the IGBT module under test.

[0028] In some embodiments, the device further includes a bus power supply unit, a current probe, and an IGBT single transistor. The positive terminal of the bus power supply unit is connected to the positive terminal of the bus power stray inductance, the negative terminal of the bus power supply unit is connected to the negative terminal of the IGBT single transistor, the positive terminal of the IGBT single transistor is connected to the negative terminal of the current probe, and the positive terminal of the current probe is connected to the negative terminal of the IGBT module under test.

[0029] In some embodiments, a first voltage probe is included, connected in parallel with the bus power supply stray inductance;

[0030] The second voltage probe is connected in parallel with the stray inductance of the stacked copper busbar;

[0031] The third voltage probe is connected in parallel with the IGBT module under test.

[0032] In some embodiments, the IGBT module under test includes an upper IGBT module and a lower IGBT module, wherein the upper IGBT module and the lower IGBT module are connected in series; it also includes an external adjustable load inductor connected in parallel with the upper IGBT module.

[0033] The beneficial effects of the technical solution provided by this invention include: this invention can measure the bus capacitance, stacked copper busbar, and total stray inductance of IGBT module separately. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart illustrating the overall process of a testing method for an IGBT circuit system according to the present invention.

[0036] Figure 2 This is a flowchart illustrating the test bus power supply stray inductance of an IGBT circuit system test method according to the present invention;

[0037] Figure 3 This is a flowchart illustrating the test method for stray inductance of multilayer copper busbars in an IGBT circuit system according to the present invention.

[0038] Figure 4 This is a flowchart illustrating the testing method for an IGBT circuit system according to the present invention, specifically for testing the total stray inductance of an IGBT module.

[0039] Figure 5 This is a general structural diagram of a test circuit for an IGBT circuit system according to the present invention;

[0040] Figure 6 This is a schematic diagram showing the current direction when a single IGBT transistor is turned on in an IGBT circuit system test circuit according to the present invention.

[0041] Figure 7 This is a schematic diagram of the current direction when a single IGBT transistor is turned off in an IGBT circuit system test circuit according to the present invention.

[0042] Figure 8 This is an example diagram of the stray inductance test pulse during the turn-off of an IGBT circuit system test circuit according to the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] See Figure 1 As shown, this embodiment of the invention provides a testing method for an IGBT circuit system, including the following steps:

[0045] S10. Apply a pulse signal to IGBT3, the single IGBT transistor;

[0046] S20. Obtain the current waveform in the total circuit through the current probe I1;

[0047] S30. Obtain the voltage waveforms at positions V1, V2, and V3 of each component using voltage probes;

[0048] S40. Test the stray inductance L1 of the bus power supply;

[0049] S50. Test the stray inductance L2 of the multilayer copper busbar;

[0050] S60. Test the total stray inductance L of the IGBT module under test.

[0051] In this embodiment, the IGBT module under test consists of an upper IGBT1 and a lower IGBT2. IGBT1 is driven by a -15V voltage, keeping it always off. IGBT2 is driven by a +15V voltage, keeping it always on. The current loop is formed through L3, IGBT2, and IGBT3. During turn-off, L3 freewheels through IGBT1. This test method treats the upper and lower IGBT modules as a single unit. By measuring the overall current I1 and overall voltage V3, the overall voltage and current waveforms of the IGBT module under test at the turn-off moment are obtained. The overall inductance of the IGBT module under test will be reflected in the measured voltage waveform, thus the overall inductance value can be calculated based on the voltage and current.

[0052] See Figure 2 As shown, optionally, step S40, testing the stray inductance L1 of the bus power supply, includes the following steps:

[0053] S41. Measure the voltage waveform across the stray inductance L1 of the bus power supply using the first voltage probe V1;

[0054] S42. Calculate the value of the stray inductance L1 of the bus power supply based on the captured voltage and current waveform signals at the turn-off moment.

[0055] See Figure 3 As shown, optionally, S50. Testing the stray inductance L2 of the multilayer copper busbar includes the following steps:

[0056] S51. Measure the voltage waveform across the stray inductance L2 of the multilayer copper busbar using the second voltage probe V2;

[0057] S52. Calculate the value of the stray inductance L2 of the multilayer copper busbar based on the captured voltage and current waveform signals at the turn-off moment.

[0058] See Figure 4 As shown, optionally, S60. Testing the total stray inductance L of the IGBT module under test includes the following steps:

[0059] S61. Measure the voltage waveforms across the positive and negative copper busbars of the IGBT module under test using the third voltage probe V3;

[0060] S62. Calculate the total stray inductance of the IGBT module under test based on the captured voltage and current waveform signals at the turn-off moment.

[0061] Optionally, the stray inductance value is calculated as follows:

[0062] L=Δu / (di / dt),

[0063] Where L is the stray inductance value, Δu is the voltage value of the stray inductance, di is the current value in the total circuit, and di / dt is the rate of change of the current in the total circuit.

[0064] In this embodiment, integrating both sides of U=L*di / dt, the integral of the voltage divided by the change in current gives the inductance value.

[0065] Derivation process:

[0066]

[0067] Integrating the above equation over the time interval t1 to t2, we get...

[0068]

[0069] From the above formula, we can derive:

[0070]

[0071] Therefore, the inductance value is obtained by dividing the integral of the voltage by the change in current.

[0072] In this embodiment, the upper IGBT1 of the IGBT module is provided with a -15V signal, and the lower IGBT2 of the IGBT module is provided with a +15V signal. When a normally low -15V signal is given to the gate of the upper IGBT1, the upper IGBT is in the off state, and an external adjustable load inductor L3 is connected in parallel with the upper IGBT. When a normally high +15V signal is given to the gate of the lower IGBT2, the lower IGBT is in the normally open state.

[0073] See Figure 6 As shown in this embodiment, when IGBT3 is turned on, the current loop can form a circuit through the external adjustable load current L3, the lower IGBT2 of the IGBT module to be tested, and IGBT3.

[0074] See Figure 7 and Figure 8 As shown in this embodiment, when IGBT3 is turned off, the current loop through the external adjustable load inductor L3 freewheels through the upper IGBT1 of the IGBT module. Since the inductor is an energy storage element, the current of L3 cannot change abruptly after IGBT3 is turned off. At this time, the freewheeling can be achieved through the diode connected in antiparallel to IGBT1. The circuit design is reasonable.

[0075] On the one hand, an IGBT circuit system test circuit is provided, including the test circuit required by the IGBT circuit system test method described in any one of the above.

[0076] See Figures 5 to 8As shown, optionally, it includes a bus power stray inductor L1, a multilayer copper bus stray inductor L2, and an IGBT module under test. The negative terminal of the bus power stray inductor L1 is connected to the positive terminal of the multilayer copper bus stray inductor L2, and the negative terminal of the multilayer copper bus stray inductor L2 is connected to the positive terminal of the IGBT module under test.

[0077] Optionally, it also includes a bus power supply device V_dc, a current probe I1, and an IGBT 3. The positive terminal of the bus power supply device V_dc is connected to the positive terminal of the bus power stray inductance L1, the negative terminal of the bus power supply device V_dc is connected to the negative terminal of the IGBT 3, the positive terminal of the IGBT 3 is connected to the negative terminal of the current probe I1, and the positive terminal of the current probe I1 is connected to the negative terminal of the IGBT module under test.

[0078] Optionally, a first voltage probe V1 is connected in parallel with the bus power supply stray inductance L1;

[0079] The second voltage probe V2 is connected in parallel with the stray inductance L2 of the multilayer copper busbar;

[0080] The third voltage probe V3 is connected in parallel with the IGBT module under test.

[0081] Optionally, the IGBT module under test includes an upper IGBT1 and a lower IGBT2, with the upper IGBT1 and the lower IGBT2 connected in series; it also includes an external adjustable load inductor connected in parallel with the upper IGBT1.

[0082] The beneficial effects of this invention are as follows:

[0083] This invention can measure bus capacitance, stacked copper busbar, and total stray inductance of IGBT module separately.

[0084] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0085] It should be noted that, in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising," or any other variation thereof, is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0086] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A test method for an IGBT circuit system, characterized in that, Includes the following steps: S10. Apply a pulse signal to a single IGBT transistor; S20. Obtain the current waveform in the total circuit using a current probe; S30. Obtain the voltage waveforms at positions V1, V2, and V3 of each component using voltage probes; S40. Test the stray inductance of the bus power supply; S50. Test stray inductance of multilayer copper busbars; S60. Test the total stray inductance of the IGBT module under test; S40. Testing the stray inductance of the bus power supply includes the following steps: S41. Measure the voltage waveform across the stray inductance of the bus power supply using the first voltage probe; S42. Calculate the value of the stray inductance of the bus power supply based on the captured voltage and current waveform signals at the turn-off moment; S50. Test the stray inductance of the multilayer copper busbar, including the following steps: S51. Measure the voltage waveform across the stray inductance of the multilayer copper busbar using the second voltage probe; S52. Calculate the value of the stray inductance of the multilayer copper busbar based on the captured voltage and current waveform signals at the turn-off moment; S60. Test the total stray inductance of the IGBT module, including the following steps: S61. Measure the voltage waveforms across the positive and negative copper busbars of the IGBT module under test using the third voltage probe; S62. Calculate the total stray inductance of the IGBT module under test based on the captured voltage and current waveform signals at the turn-off moment.

2. The IGBT circuit system testing method as described in claim 1, characterized in that, The stray inductance value is calculated as follows: L=Δu / (di / dt) Where L is the stray inductance value, Δu is the voltage value of the stray inductance, di is the current value in the total circuit, and di / dt is the rate of change of the current in the total circuit.

3. A test circuit for an IGBT circuit system, characterized in that, The test circuit includes the IGBT circuit system test method described in claim 1 or 2.

4. The IGBT circuit system test circuit as described in claim 3, characterized in that, The device includes a bus power stray inductor, a multilayer power stray inductor, and an IGBT module under test. The negative terminal of the bus power stray inductor is connected to the positive terminal of the multilayer copper bus stray inductor, and the negative terminal of the multilayer copper bus stray inductor is connected to the positive terminal of the IGBT module under test.

5. The IGBT circuit system test circuit as described in claim 4, characterized in that, It also includes a bus power supply device, a current probe, and an IGBT single tube. The positive terminal of the bus power supply device is connected to the positive terminal of the stray inductance of the bus power supply, the negative terminal of the bus power supply device is connected to the negative terminal of the IGBT single tube, the positive terminal of the IGBT single tube is connected to the negative terminal of the current probe, and the positive terminal of the current probe is connected to the negative terminal of the IGBT module under test.

6. The IGBT circuit system test circuit as described in claim 4, characterized in that, Includes a first voltage probe, connected in parallel with the stray inductance of the bus power supply; The second voltage probe is connected in parallel with the stray inductance of the stacked copper busbar; The third voltage probe is connected in parallel with the IGBT module under test.

7. The IGBT circuit system test circuit as described in claim 3, characterized in that, The IGBT module under test includes an upper IGBT module and a lower IGBT module, with the upper IGBT module and the lower IGBT module connected in series; it also includes an external adjustable load inductor connected in parallel with the upper IGBT module.

Images