Thermal resistance testing method, circuit and equipment based on thermal coupling

Abstract

The invention discloses a thermal resistance testing method, circuit and equipment based on thermal coupling. The method comprises the following steps: firstly, constructing a thermal resistance testing circuit comprising a to-be-tested device; then determining a temperature coupling state of the device to be tested based on the thermal resistance test circuit; and finally, determining the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested. The thermal resistance test circuit is wide in application range, and the thermal resistance test efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of thermal parameter testing of power semiconductor devices, and particularly relates to a thermal resistance testing method, circuit and equipment based on thermal coupling. BACKGROUND

[0002] High-voltage and high-power power electronic devices have been fully applied to new energy power generation, flexible direct current transmission, electric locomotive traction and electric vehicles, etc. In these applications, power electronic devices usually work in a harsh operating environment and face severe reliability challenges. Health management and reliability evaluation of power electronic devices have attracted more and more attention from the academic and industrial circles. According to the power electronic system reliability research report, temperature is the main cause of failure of power devices in power electronic systems, and it can be seen that the junction temperature on-line monitoring of power devices is very important for improving the reliability of the entire power electronic system. The thermal resistance is an important evaluation index reflecting the heat dissipation performance of the power device. However, the existing thermal resistance test only considers the single heat source of the power module. In the actual device application condition, the IGBT and its anti-parallel diode are both heated, and the thermal resistance of the IGBT is affected by the parallel diode, which is quite different from the thermal resistance measured in the conventional thermal resistance test. This becomes a technical problem that needs to be solved urgently. SUMMARY

[0003] The purpose of the present application is to provide a thermal resistance testing method, circuit and equipment based on thermal coupling to solve the problems in the prior art. The thermal resistance testing circuit in the present application has a wide range of applications and can improve the thermal resistance testing efficiency.

[0004] One embodiment of the present application provides a thermal resistance testing method based on thermal coupling, which comprises the following steps: constructing a thermal resistance testing circuit containing a device to be tested; determining the temperature coupling state of the device to be tested based on the thermal resistance testing circuit; determining the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested.

[0005] Optionally, the step of determining the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested comprises the following steps: calibrating the current source of the thermal resistance testing circuit to pass into the device to be tested based on the temperature coupling state of the device to be tested, and obtaining the junction temperature corresponding to each temperature, the saturation on-voltage drop of the device to be tested and the current flowing through the device to be tested by a small current method. .

[0006] Optionally, the thermal resistance of thermal coupling is determined by the following formula: ​​​

[0007] wherein, represents thermal resistance of thermal coupling, represents junction temperature of the device under test, represents case temperature of the device under test, represents saturation on-state voltage drop of the device under test, represents current flowing through the device under test during the test.

[0008] Yet another embodiment of the present application provides a thermal resistance test circuit based on thermal coupling, the circuit comprising: an AC pulse current source, a control switch, a device under test, a gate signal, and a measurement current source.

[0009] Optionally, the AC pulse current source is configured to provide an alternating current pulse signal. The control switch is configured to control on-off of the current loop. The device under test comprises a power device with an anti-parallel diode. The gate signal is composed of complementary signals, and the signal frequency range includes 1 kHz to 1 MHz. The measurement current source is configured to provide a measurement current with an amplitude ranging from 1 mA to 500 mA.

[0010] Optionally, the device under test comprises a first bridge arm device and a second bridge arm device in parallel; the first bridge arm device comprises a first IGBT unit and a first diode, the first IGBT unit is configured to provide a forward loop, and the first diode is configured to provide a reverse loop; the second bridge arm device comprises a second IGBT unit and a second diode, the second IGBT unit is configured to provide a reverse loop, and the second diode is configured to provide a forward loop.

[0011] Optionally, the positive electrode of the AC pulse current source is connected to the collector C end of the control switch, the emitter E end of the control switch is connected to the collector C end of the first bridge arm device, the emitter E end of the first bridge arm device is connected to the collector C end of the second bridge arm device, and the emitter E end of the second bridge arm device is connected to the negative electrode of the AC pulse current source.

[0012] Optionally, the first bridge arm device and the second bridge arm device are respectively connected to a first bridge arm device measurement current source and a second bridge arm device measurement current source from the collector C end.

[0013] Yet another embodiment of the present application provides a thermal resistance test device based on thermal coupling, which utilizes any one of the thermal resistance test methods described above or comprises any one of the thermal resistance test circuits described above.

[0014] Compared with the prior art, the application firstly constructs a thermal resistance test circuit containing a device to be tested; then determines the temperature coupling state of the device to be tested based on the thermal resistance test circuit; and finally determines the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested. The thermal resistance test circuit in the application has a wide application range and can improve the thermal resistance test efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A flowchart of a thermal resistance test method based on thermal coupling provided for an embodiment of the application; Figure 2 A circuit diagram of a thermal resistance test circuit based on thermal coupling provided for an embodiment of the application. DETAILED DESCRIPTION

[0016] The embodiments described below with reference to the drawings are exemplary and are only used to explain the application, and cannot be explained as a limitation of the application.

[0017] Reference Figure 1 , Figure 1 A flowchart of a thermal resistance test method based on thermal coupling provided for an embodiment of the application can include the following steps: S101: Constructing a thermal resistance test circuit containing a device to be tested.

[0018] S102: Determining the temperature coupling state of the device to be tested based on the thermal resistance test circuit.

[0019] S103: Determining the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested.

[0020] Specifically, constructing a thermal resistance test circuit containing a device to be tested (DUT) is the basis of thermal resistance test. The circuit not only needs to be safe and stable, but also needs to reflect the thermal characteristics of the device to be tested in the working process. The above-mentioned thermal resistance test circuit can be used to monitor the temperature change of the device to be tested under different working conditions, and by changing the parameters in the circuit, the temperature response of the device to be tested can be observed. What needs to be determined is the thermal coupling state between the device to be tested and other elements, which will affect the heat dissipation efficiency of the device to be tested, and thus affect its thermal resistance.

[0021] It should be noted that before the thermal resistance test, the device to be tested can be calibrated by a small current method, that is, the device to be tested is heated, and the junction temperature corresponding to each temperature is recorded in real time for calculation of the transient thermal impedance curve.

[0022] ​​In an alternative embodiment, the determining the thermal resistance of the thermal coupling according to the temperature coupling state of the device under test can comprise: calibrating the current source of the thermal resistance test circuit to pass through the device under test based on the temperature coupling state of the device under test, and obtaining the junction temperature corresponding to each temperature by small current method, the saturation on-voltage of the device under test, and the current flowing through the device under test. .

[0023] wherein the thermal resistance of the thermal coupling is determined by the following formula:

[0024] wherein, Rth represents the thermal resistance of the thermal coupling, Tj represents the junction temperature of the device under test, Tc represents the case temperature of the device under test, Von represents the saturation on-voltage of the device under test, and I represents the current flowing through the device under test.

[0025] Similarly, the junction to cooling water thermal resistance and the junction to ambient thermal resistance can also be calculated according to the formula.

[0026] After determining the temperature coupling state of the device under test, the information can be used to calculate its thermal resistance. Thermal resistance is a physical quantity that describes the ease of heat transfer in an object, which is equal to the temperature difference between the two ends of the object and the heat passing through the object. In the test circuit, the thermal resistance can be calculated by measuring the temperature change of the device under test and the related heat flow.

[0027] Exemplarily, a thermal resistance test circuit based on thermal coupling can at least include: an alternating current pulse current source, a control switch, a device under test, a gate signal, and a measurement current source.

[0028] The alternating current pulse current source is used to provide an alternating current pulse signal; the control switch is used to control the on-off of the current loop; the device under test includes a power device with a reverse-parallel diode; the gate signal is composed of complementary signals, and the signal frequency range includes 1 kHz to 1 MHz; the measurement current source is used to provide a measurement current with an amplitude of 1 mA to 500 mA.

[0029] Referring to Figure 2 , Figure 2The circuit schematic of the thermal resistance test circuit based on thermal coupling provided by the embodiment of the present application can include a load current source (or an alternating current pulse current source), a control switch, a device to be tested, gate signals (including a first bridge arm gate voltage and a second bridge arm gate voltage), and a measurement current source. The device to be tested includes a first bridge arm device and a second bridge arm device in parallel. The first bridge arm device includes a first IGBT unit and a first diode, the first IGBT unit is used to provide a forward loop, and the first diode is used to provide a reverse loop. The second bridge arm device includes a second IGBT unit and a second diode, the second IGBT unit is used to provide a reverse loop, and the second diode is used to provide a forward loop. The positive electrode of the alternating current pulse current source is connected to the collector C end of the control switch, the emitter E end of the control switch is connected to the collector C end of the first bridge arm device, the emitter E end of the first bridge arm device is connected to the collector C end of the second bridge arm device, and the emitter E end of the second bridge arm device is connected to the negative electrode of the alternating current pulse current source. The first bridge arm device and the second bridge arm device are connected to the first bridge arm device measurement current source and the second bridge arm device measurement current source from the collector C end respectively.

[0030] It should be noted that IGBT (Insulated Gate Bipolar Transistor) is a kind of composite full-controlled voltage-driven power semiconductor device. It combines the advantages of BJT (Bipolar Junction Transistor) and MOSFET (Insulated Gate Field Effect Transistor) in one, and has the advantages of high input impedance, small driving power, fast switching speed, low on-state voltage, high voltage resistance, and large current bearing capacity. In practical applications, IGBT is mainly used as a high-voltage and large-current power switching device.

[0031] For example, the alternating current pulse current source is used to provide an alternating current pulse signal to stimulate the heating effect of the device to be tested. The positive electrode is connected to the collector C end of the control switch, and the negative electrode is connected to the emitter E end of the second bridge arm device. The control switch is used to control the on-off of the current loop, thereby controlling the working state of the device to be tested. The collector C end is connected to the positive electrode of the alternating current pulse current source, and the emitter E end is connected to the collector C end of the first bridge arm device. The device to be tested includes a first bridge arm device and a second bridge arm device in parallel, and each bridge arm device is composed of an IGBT unit and a reverse-parallel diode. The IGBT unit of the first bridge arm device provides a forward loop, and the diode provides a reverse loop; the second bridge arm device is the opposite. The gate signal is composed of complementary signals, and the signal frequency range includes 1 kHz to 1 MHz, which is used to control the turn-on and turn-off of the IGBT unit. The measurement current source is used to provide a measurement current with an amplitude of 1 mA to 500 mA, which is used to monitor the temperature change of the device to be tested, and the measurement current is connected to the collector C end of the first bridge arm device and the second bridge arm device respectively.

[0032] The positive pole of the alternating pulse current source is connected to the collector C end of the control switch through a wire, and the emitter E end of the control switch is connected to the collector C end of the first bridge arm device (consisting of a first IGBT unit and a first diode) through a wire. The emitter E end of the first bridge arm device is connected to the collector C end of the second bridge arm device (consisting of a second IGBT unit and a second diode) through a wire. The emitter E end of the second bridge arm device is connected to the negative pole of the alternating pulse current source through a wire, forming a closed current loop. The collectors C ends of the first bridge arm device and the second bridge arm device are respectively connected to the respective measurement current sources through wires for providing measurement currents and monitoring temperature changes. The gate signals are respectively connected to the gates of the IGBT units of the first bridge arm and the second bridge arm for controlling the turn-on and turn-off of the IGBTs.

[0033] After the thermal resistance test circuit is connected, the control switch is opened, the alternating pulse current source is opened, the gate signal triggers the complementary signal, so that the alternating current passes through the device to be tested at high frequency, so that the device IGBT and the diode jointly heat to create a temperature coupling state. Turn off the current source, and turn on the calibration current source to the positive direction of the device to be tested. By using the above small current method, the junction temperature of the device to be tested can be solved by measuring the saturation voltage drop and bringing in the calibration curve. The thermal resistance of the thermal coupling can be inversely solved by the above calculation formula of determining the thermal resistance of the thermal coupling.

[0034] The present application proposes a thermal resistance test method based on thermal coupling, proposes a thermal resistance measurement method that fits the actual situation, and can accurately evaluate the thermal resistance of power devices. The main purpose is to solve the problem that the current thermal resistance test method cannot truly reflect the thermal resistance of the device under actual working conditions. Through innovation in the thermal resistance test method, combined with the basic principles of traditional thermal resistance test methods, a power device thermal resistance measurement method suitable for considering thermal coupling is proposed. The thermal resistance test method proposed in the present application is not only suitable for IGBT modules, but also for any power module with parallel diodes.

[0035] Compared with various existing thermal resistance test devices, the present application has the following technical effects: 1. The thermal resistance test method in the present application can perform thermal resistance tests under various different test conditions, meet the requirements of all current thermal resistance test methods, and can propose different thermal resistance test schemes combined with the needs of semiconductor manufacturers, filling the gap of thermal resistance test methods that fit the actual working conditions of thermal coupling effects; 2. The thermal resistance test element in the present application has a wide range of applications and is universal, and can provide thermal resistance tests for power device modules with anti-parallel diodes, not only for IGBT modules, but also for GaN, SiC modules, etc. 3. The thermal resistance test circuit has high test efficiency, and can simultaneously perform thermal resistance test on 12 devices to be tested, thereby significantly improving the test quantity compared with the traditional thermal resistance equipment of Mentor.

[0036] It can be seen that the application first constructs a thermal resistance test circuit containing a device to be tested; then determines the temperature coupling state of the device to be tested based on the thermal resistance test circuit; and finally determines the thermal resistance of thermal coupling according to the temperature coupling state of the device to be tested. The thermal resistance test circuit in the application has a wide application range and can improve the thermal resistance test efficiency.

[0037] Another embodiment of the application provides a thermal resistance test device based on thermal coupling, which utilizes the thermal resistance test method described above or comprises the thermal resistance test circuit described above.

[0038] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the application is not limited to the action sequence described, because according to the application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily necessary for the application.

[0039] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0040] In several embodiments provided by the application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic. The division of the above units is only a logical function division. There can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical or other forms.

[0041] The units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e. can be located in one place, or can be distributed on a plurality of network units. According to actual needs, some or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0042] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit.

[0043] When the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable memory. Based on this understanding, the technical solutions of the present application or the part that essentially contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a memory and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the above-mentioned method of each embodiment of the present application. The aforementioned memory includes: a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk and various program code storage media.

[0044] The embodiments of the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed, and the above description should not be understood as a limitation of the present application.

Claims

1. A thermal resistance testing method based on thermal coupling, characterized in that: The method includes: Construct a thermal resistance test circuit containing the device under test; Determining a temperature coupling state of the device under test based on the thermal resistance test circuit; The thermal resistance of the thermal coupling is determined according to the temperature coupling state of the device under test.

2. The method according to claim 1, characterized in that Determining the thermal resistance of thermal coupling according to the temperature coupling state of the device under test includes: Based on the temperature coupling state of the device under test, the current source of the thermal resistance test circuit is calibrated and passed into the device under test, and a small current is passed through the device under test. Method to obtain the junction temperature corresponding to each temperature , the saturation conduction voltage drop of the device under test and the current flowing through the device under test .

3. The method according to claim 2, characterized in that The thermal resistance of the thermal coupling is determined by the following formula: in, represents the thermal resistance of the thermal coupling, Indicates the junction temperature of the device under test, Indicates the case temperature of the device under test, It represents the saturation conduction voltage drop of the device under test. Indicates the current flowing through the device under test during the test.

4. A thermal resistance test circuit based on thermal coupling, characterized in that: The circuit comprises: AC pulse current source, control switch, device under test, gate signal, and measurement current source.

5. The thermal resistance test circuit according to claim 4, characterized in that: The AC pulse current source is used to provide an alternating current pulse signal; The control switch is used to control the on and off of the current loop; The device under test includes a power device with an anti-parallel diode; The gate signal is composed of complementary signals, and the signal frequency range includes 1kHz to 1MHz; The measurement current source is used to provide measurement currents with amplitudes ranging from 1 mA to 500 mA.

6. The thermal resistance test circuit according to claim 4, characterized in that: The device under test includes a first bridge arm device and a second bridge arm device connected in parallel; the first bridge arm device includes a first IGBT unit and a first diode, the first IGBT unit is used to provide a forward circuit, and the first diode is used to provide a reverse circuit; the second bridge arm device includes a second IGBT unit and a second diode, the second IGBT unit is used to provide a reverse circuit, and the second diode is used to provide a forward circuit.

7. The thermal resistance test circuit according to claim 5, characterized in that: The positive electrode of the AC pulse current source is connected to the collector C terminal of the control switch, the emitter E terminal of the control switch is connected to the collector C terminal of the first bridge arm device, the emitter E terminal of the first bridge arm device is connected to the collector C terminal of the second bridge arm device, and the emitter E terminal of the second bridge arm device is connected to the negative electrode of the AC pulse current source.

8. The thermal resistance test circuit according to claim 7, characterized in that: The first bridge arm device and the second bridge arm device are connected to the first bridge arm device measurement current source and the second bridge arm device measurement current source respectively from the collector C terminal.

9. A thermal resistance test device based on thermal coupling, characterized in that: The thermal resistance testing device based on thermal coupling utilizes the thermal resistance testing method according to any one of claims 1 to 3, or includes the thermal resistance testing circuit according to any one of claims 4 to 8.

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