A method and apparatus for online evaluation of junction temperature of a power semiconductor module

Abstract

The application discloses a kind of power semiconductor module junction temperature online evaluation method and device, belong to electronic device electrical and thermal measurement technical field, method includes: recording the transient temperature rise curve at temperature sensor;Record the transient temperature drop curve at chip;The transient temperature drop curve at chip is converted into the transient temperature rise curve at chip;According to the transient temperature rise curve at chip and the transient temperature rise curve at temperature sensor, calculate the transient thermal resistance of chip to temperature sensor;According to the pre-constructed thermal resistance thermal capacity network FOSTER model, the transient thermal resistance of chip to temperature sensor is fitted, to obtain the transient thermal resistance curve of chip to temperature sensor;According to the transient thermal resistance curve of chip to temperature sensor, calculate the pulse thermal resistance of chip to temperature sensor;According to the pulse thermal resistance of chip to temperature sensor, calculate the junction temperature of power semiconductor module.The junction temperature of power semiconductor module can be calculated by the pulse thermal resistance of chip to temperature sensor in the application.

Description

TECHNICAL FIELD

[0001] The application relates to a power semiconductor module junction temperature online evaluation method and device, and belongs to the technical field of electrical and thermal measurement of electronic devices. BACKGROUND

[0002] Internal temperature evaluation of a power semiconductor module is crucial to its reliability, and the junction temperature refers to the temperature of an active region of a chip inside the power semiconductor module, which is generally the highest point of the internal temperature, and currently, the junction temperature is mainly calculated through junction shell thermal resistance, that is, the junction temperature is calculated by measuring the temperature of a heat dissipation shell combined with the junction shell thermal resistance, but in actual application, the measurement of the shell temperature is difficult.

[0003] Part of the power semiconductor modules embeds a temperature sensor (such as a thermistor NTC) inside the module, and the junction temperature is simply evaluated by measuring the temperature of the temperature sensor, but there is a large gap between the sensor temperature and the junction temperature, and the gap is different under different application conditions, so the junction temperature cannot be accurately evaluated. SUMMARY

[0004] The application aims to provide a power semiconductor module junction temperature online evaluation method and device, and the junction temperature of the power semiconductor module is calculated through the pulse thermal resistance from the chip to the temperature sensor.

[0005] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0006] In a first aspect, the application provides a power semiconductor module junction temperature online evaluation method, which comprises:

[0007] The power semiconductor module is connected to a power supply to heat the power semiconductor module, and a temperature acquisition device is used to record the transient temperature rise curve N(t) at the temperature sensor;

[0008] The power semiconductor module is disconnected from the power supply, and the power semiconductor module is converted from heating to cooling through a liquid cooling platform, and a temperature acquisition device is used to record the transient temperature drop curve b(t) at the chip;

[0009] The transient temperature drop curve b(t) at the chip is converted into the transient temperature rise curve a(t) at the chip;

[0010] The transient thermal resistance Zth from the chip to the temperature sensor is calculated according to the transient temperature rise curve a(t) at the chip and the transient temperature rise curve N(t) at the temperature sensor;

[0011] The transient thermal resistance Zth from the chip to the temperature sensor is fitted according to a pre-constructed thermal resistance and heat capacity network FOSTER model to obtain the transient thermal resistance curve Zthj-N from the chip to the temperature sensor;

[0012] According to the transient thermal resistance curve Zthj-N of the chip to the temperature sensor, a pulse thermal resistance Zthj-N(pulse) of the chip to the temperature sensor is calculated;

[0013] According to the pulse thermal resistance Zthj-N(pulse) of the chip to the temperature sensor, in combination with the temperature at the temperature sensor measured in actual application, the junction temperature of the power semiconductor module is calculated.

[0014] In combination with the first aspect, further, the temperature sensor is replaced by a temperature measuring diode, so that the sampling rate reaches 1 MHz.

[0015] In combination with the first aspect, further, the power semiconductor module is disconnected from the power supply, and the time taken for the power semiconductor module to change from the process of heating to the process of cooling by the liquid cooling platform is less than 10 μs.

[0016] In combination with the first aspect, further, the calculation formula used for converting the transient temperature drop curve b(t) at the chip into the transient temperature rise curve a(t) at the chip is shown in formula (1):

[0017] a(t) = deltaTjmax - b(t) (1)

[0018] In formula (1), a(t) is the transient temperature rise curve at the chip, b(t) is the transient temperature drop curve at the chip, and deltaTjmax is the highest junction temperature rise of the chip when the power semiconductor module is heated.

[0019] In combination with the first aspect, further, the calculation formula used for calculating the transient thermal resistance Zth of the chip to the temperature sensor according to the transient temperature rise curve a(t) at the chip and the transient temperature rise curve N(t) at the temperature sensor is shown in formula (2):

[0020]

[0021] In formula (2), Zth is the transient thermal resistance of the chip to the temperature sensor, a(t) is the transient temperature rise curve at the chip, N(t) is the transient temperature rise curve at the temperature sensor, and P is the power applied to the power semiconductor module by the power supply.

[0022] In combination with the first aspect, further, the expression of the transient thermal resistance curve Zthj-N of the chip to the temperature sensor is shown in formula (3):

[0023]

[0024] In formula (3), i is the number of thermal resistance and heat capacity network units in the thermal resistance and heat capacity network FOSTER model, R iis the first fitting parameter of the i-th thermal resistance-capacitance network unit, t is the power semiconductor module temperature rise time, τ i is the second fitting parameter of the i-th thermal resistance-capacitance network unit.

[0025] In combination with the first aspect, further, the expression of the chip-to-temperature sensor pulse thermal resistance Zthj-N(pulse) is shown in equation (4):

[0026]

[0027] In equation (4), z is a value obtained by taking logarithm of the power semiconductor module temperature rise time, R(z) is a time constant spectrum, δ is a duty cycle of the continuous pulse, t1 is a pulse width of the continuous pulse, x is a value obtained by taking logarithm of the pulse width t1 of the continuous pulse, is a convolution operator symbol;

[0028] In which, the expression of the time constant spectrum R(z) is shown in equation (5):

[0029]

[0030] In equation (5), z is a value obtained by taking logarithm of the power semiconductor module temperature rise time, R(z) is a time constant spectrum, a(z) is an expression of the chip-to-temperature sensor transient thermal resistance curve corresponding to the logarithm of the power semiconductor module temperature rise time, a(z) = Zthj-N(z = lnt), w z (z) is an intermediate variable, w z (z) = exp[z-exp(z)], is an anti-convolution operator symbol.

[0031] In the second aspect, the application provides a power semiconductor module junction temperature online evaluation device, comprising: a power semiconductor module, a power supply, a temperature acquisition device and a computer; further comprising a liquid cooling platform for cooling the power semiconductor module; the power semiconductor module comprises a temperature sensor and a chip, the temperature acquisition device is connected between the power semiconductor module and the computer; the power semiconductor module and the computer are respectively electrically connected with the power supply.

[0032] Compared with the prior art, the application has the following beneficial effects:

[0033] 1. The junction temperature is calculated by the pulse thermal resistance from the junction temperature point to the temperature sensor position, and the temperature of the temperature sensor can be measured online in the actual application process, and the junction temperature change is calculated in real time according to the pulse thermal resistance curve.

[0034] 2. The temperature sampling frequency is higher and the calculation is more accurate by replacing the ordinary temperature sensor with a temperature sampling diode.

[0035] 3. The method can be applied to various power semiconductor modules with embedded temperature sensors. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a power semiconductor module junction temperature online evaluation method flowchart provided by an embodiment of the present application;

[0037] Figure 2 is a schematic diagram of the connection relationship of various components in a power semiconductor module junction temperature online evaluation device provided by an embodiment of the present application;

[0038] Figure 3 is a schematic diagram of a transient temperature drop curve b(t) at a chip provided by an embodiment of the present application;

[0039] Figure 4 is a schematic diagram of a transient temperature rise curve a(t) at a chip and a transient temperature rise curve N(t) at a temperature sensor provided by an embodiment of the present application;

[0040] Figure 5 is a schematic diagram of a transient thermal resistance curve Zthj-N from a chip to a temperature sensor provided by an embodiment of the present application;

[0041] Figure 6 is a schematic diagram of a pulse thermal resistance Zthj-N(pulse) from a chip to a temperature sensor provided by an embodiment of the present application;

[0042] In the figure: 1-power semiconductor module, 2-temperature measurement diode, 3-power supply, 4-temperature acquisition device, 5-liquid cooling platform, 6-computer. DETAILED DESCRIPTION

[0043] The technical solutions of the present application will be further described in detail below in combination with specific embodiments.

[0044] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. The technical features in the embodiments and the embodiments can be combined with each other without conflict.

[0045] Embodiment one:

[0046] Figure 1 is a power semiconductor module junction temperature online evaluation method flowchart provided by an embodiment one of the present application, and the flowchart only shows the logical order of the method of the embodiment, and in other possible embodiments of the present application, the technical features can be different from the technical features in the flowchart on the premise of not conflicting with each other. Figure 1The steps shown or described are accomplished in the order shown.

[0047] See also Figure 1 The method of this embodiment specifically includes the following steps:

[0048] Step 1: Connect the power semiconductor module to the power supply to heat up the power semiconductor module, and record the transient temperature rise curve N(t) at the temperature sensor through the temperature acquisition device;

[0049] According to the calculation principle of the FOSTER thermal resistance network model, the power semiconductor module is connected to a power supply, which applies power to the module and heats it. As the temperature of the module rises, sufficient heating time must be maintained to ensure that the module reaches thermal steady-state, meaning that the chip temperature remains stable and does not rise further. Furthermore, due to the slow response speed of temperature sensors such as thermistors, the 1MHz sampling rate required for network model calculations cannot be achieved. Therefore, the temperature sensor is replaced with a temperature measuring diode to achieve a 1MHz sampling rate.

[0050] Step 2: Disconnect the power supply of the power semiconductor module and use a liquid cooling platform to switch the temperature of the power semiconductor module from rising to falling. Use a temperature acquisition device to record the transient temperature drop curve b(t) at the chip.

[0051] To ensure that the thermal resistance information is not lost, the power semiconductor module is disconnected from the power supply and the liquid cooling platform is used to convert the power semiconductor module from heating to cooling. The time taken is less than 10μs. The schematic diagram of the measured transient temperature drop curve b(t) at the chip is shown in the figure below. Figure 3 shown.

[0052] Step 3: Convert the transient temperature drop curve b(t) at the chip into the transient temperature rise curve a(t) at the chip;

[0053] The calculation formula used to convert the transient temperature drop curve b(t) at the chip into the transient temperature rise curve a(t) at the chip is shown in formula (1):

[0054] a(t)=deltaTjmax-b(t) (1)

[0055] In formula (1), a(t) is the transient temperature rise curve at the chip, b(t) is the transient temperature drop curve at the chip, and deltaTjmax is the maximum junction temperature rise of the chip when the power semiconductor module is heated.

[0056] The transient temperature rise curve a(t) at the chip obtained by calculation and the transient temperature rise curve N(t) at the temperature sensor measured by the temperature acquisition device are shown in the figure below: Figure 4 shown.

[0057] Step four: Calculate the transient thermal resistance Zth from the chip to the temperature sensor according to the transient temperature rise curve a(t) at the chip and the transient temperature rise curve N(t) at the temperature sensor;

[0058] The calculation formula used to calculate the transient thermal resistance Zth from the chip to the temperature sensor according to the transient temperature rise curve a(t) at the chip and the transient temperature rise curve N(t) at the temperature sensor is shown in formula (2):

[0059]

[0060] In formula (2), Zth is the transient thermal resistance from the chip to the temperature sensor, a(t) is the transient temperature rise curve at the chip, N(t) is the transient temperature rise curve at the temperature sensor, and P is the power applied to the power semiconductor module by the power supply.

[0061] Step five: Fit the transient thermal resistance Zth from the chip to the temperature sensor according to the pre-constructed thermal resistance and heat capacity network FOSTER model to obtain the transient thermal resistance curve Zthj-N from the chip to the temperature sensor;

[0062] The expression of the transient thermal resistance curve Zthj-N from the chip to the temperature sensor is shown in formula (3):

[0063]

[0064] In formula (3), i is the number of thermal resistance and heat capacity network units in the thermal resistance and heat capacity network FOSTER model, R i is the first fitting parameter of the i-th thermal resistance and heat capacity network unit, t is the temperature rise time of the power semiconductor module, and τ i is the second fitting parameter of the i-th thermal resistance and heat capacity network unit.

[0065] The schematic diagram of the transient thermal resistance curve Zthj-N from the chip to the temperature sensor obtained by fitting is shown in Figure 5 .

[0066] Step six: Calculate the pulse thermal resistance Zthj-N(pulse) from the chip to the temperature sensor according to the transient thermal resistance curve Zthj-N from the chip to the temperature sensor and the temperature at the temperature sensor measured in actual application;

[0067] The expression of the pulse thermal resistance Zthj-N(pulse) from the chip to the temperature sensor is shown in formula (4):

[0068]

[0069] In formula (4), z is the value obtained by taking the logarithm of the heating time of the power semiconductor module, R(z) is the time constant spectrum, δ is the duty cycle of the continuous pulse, t1 is the pulse width of the continuous pulse, and x is the value obtained by taking the logarithm of the pulse width t1 of the continuous pulse. is the convolution operator symbol;

[0070] The expression of the time constant spectrum R(z) is shown in formula (5):

[0071]

[0072] In formula (5), z is the value obtained by taking the logarithm of the heating time of the power semiconductor module, R(z) is the time constant spectrum, a(z) is the expression of the transient thermal resistance curve from the chip to the temperature sensor corresponding to the logarithm of the heating time of the power semiconductor module, a(z) = Zthj - N(z = lnt), w z (z) is the intermediate variable, w z (z) = exp[z - exp(z)], is the deconvolution operator symbol.

[0073] The pulse thermal resistance Zthj-N(pulse) from the chip to the temperature sensor obtained by calculation is shown in the following figure: Figure 6 shown.

[0074] Step 7: Calculate the junction temperature of the power semiconductor module based on the pulse thermal resistance Zthj-N(pulse) from the chip to the temperature sensor.

[0075] The online evaluation method for the junction temperature of a power semiconductor module provided in this embodiment calculates the junction temperature through the pulse thermal resistance from the junction temperature point to the temperature sensor position. In actual application, the temperature of the temperature sensor can be measured online, and the junction temperature change can be calculated in real time based on the pulse thermal resistance curve. The sampling frequency is higher and the calculation is more accurate by replacing the ordinary temperature sensor with a temperature measuring diode. In addition, this method can be applied to various power semiconductor modules with embedded temperature sensors.

[0076] Example 2:

[0077] This embodiment provides a device for online evaluation of junction temperature of a power semiconductor module. Figure 2 As shown, the system includes: a power semiconductor module 1, a power supply 3, a temperature acquisition device 4, and a computer 6; a liquid cooling platform 5 for cooling the power semiconductor module; the power semiconductor module 1 includes a temperature sensor and a chip, and the temperature acquisition device 4 is connected between the power semiconductor module 1 and the computer 6; the power semiconductor module 1 and the computer 6 are each electrically connected to the power supply 3. To achieve a sampling rate of 1 MHz, the temperature sensor is replaced with a temperature measuring diode 2, which is connected between the power semiconductor module 1 and the temperature acquisition device 4.

[0078] The power semiconductor module junction temperature online evaluation device provided by the embodiments of the present application can execute the power semiconductor module junction temperature online evaluation method provided by any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0079] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A method for online evaluation of junction temperature of a power semiconductor module, characterized in that: include: Connect the power semiconductor module to the power supply to heat up the power semiconductor module, and record the transient temperature rise curve at the temperature sensor through the temperature acquisition device. ; Disconnect the power supply of the power semiconductor module and use the liquid cooling platform to convert the power semiconductor module from heating to cooling. Use the temperature acquisition equipment to record the transient temperature drop curve at the chip. ; The transient temperature drop curve at the chip Converted into transient temperature rise curve at the chip ; According to the transient temperature rise curve at the chip Transient temperature rise curve at the temperature sensor , calculate the transient thermal resistance from the chip to the temperature sensor ; Based on the pre-built thermal resistance and heat capacitance network FOSTER model, the transient thermal resistance from the chip to the temperature sensor is calculated. Fitting to obtain the transient thermal resistance curve from chip to temperature sensor ; According to the transient thermal resistance curve from chip to temperature sensor , calculate the pulse thermal resistance from the chip to the temperature sensor ; According to the pulse thermal resistance from chip to temperature sensor , combined with the temperature at the temperature sensor measured in actual applications, calculate the junction temperature of the power semiconductor module.

2. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: The temperature sensor is replaced with a temperature measuring diode to achieve a sampling rate of 1 MHz.

3. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: The time taken to disconnect the power semiconductor module from the power supply and convert the temperature rise to the temperature fall through the liquid cooling platform is less than .

4. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: The transient temperature drop curve at the chip Converted into transient temperature rise curve at the chip The calculation formula used is shown in formula (1): （1） In formula (1), is the transient temperature rise curve at the chip, is the transient temperature drop curve at the chip, It is the maximum junction temperature rise of the chip when the power semiconductor module heats up.

5. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: According to the transient temperature rise curve at the chip Transient temperature rise curve at the temperature sensor , calculate the transient thermal resistance from the chip to the temperature sensor The calculation formula used is shown in formula (2): （2） In formula (2), is the transient thermal resistance from chip to temperature sensor, is the transient temperature rise curve at the chip, is the transient temperature rise curve at the temperature sensor, The power applied by the power supply to the power semiconductor module.

6. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: Transient thermal resistance curve from chip to temperature sensor The expression of is shown in formula (3): （3） In formula (3), is the number of thermal resistance and capacitance network units in the FOSTER model of thermal resistance and capacitance network, For the The first fitting parameters of the thermal resistance and heat capacitance network units, is the heating time of the power semiconductor module, For the The second fitting parameter of the thermal resistance and heat capacitance network unit.

7. The method for online evaluation of junction temperature of a power semiconductor module according to claim 1, wherein: The pulse thermal resistance of the chip to the temperature sensor The expression of is shown in formula (4): (4) In formula (4), is the value obtained by taking the logarithm of the power semiconductor module heating time. is the time constant spectrum, is the duty cycle of the continuous pulse, is the pulse width of the continuous pulse, is the pulse width of the continuous pulse The value obtained by taking the logarithm is , is the convolution operator symbol; Wherein, the time constant spectrum The expression of is shown in formula (5): （5） In formula (5), is the value obtained by taking the logarithm of the power semiconductor module heating time. is the time constant spectrum, is the expression of the transient thermal resistance curve from the chip to the temperature sensor corresponding to the logarithm of the power semiconductor module heating time. is an intermediate variable, , is the deconvolution operator symbol.

8. A device for online evaluation of power semiconductor module junction temperature according to the method for online evaluation of power semiconductor module junction temperature according to any one of claims 1 to 7, characterized in that: include: A power semiconductor module, a power supply, a temperature acquisition device and a computer; also including a liquid cooling platform for cooling the power semiconductor module; the power semiconductor module includes a temperature sensor and a chip, the temperature acquisition device is connected between the power semiconductor module and the computer; the power semiconductor module and the computer are respectively electrically connected to the power supply.

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