Method and system for estimating junction temperature of a power semiconductor device of a power module

Abstract

The present invention relates to a method and system for estimating the junction temperature of a power semiconductor device of a power module. The method comprises: calculating a junction temperature prediction value of a first power semiconductor device based on the power loss and thermal resistance of the first power semiconductor device, and calculating a junction temperature prediction value of a second power semiconductor device based on the power loss and thermal resistance of the second power semiconductor device. The temperature prediction value of a heat sink is calculated by subtracting the junction temperature prediction value of the first power semiconductor device from the sensed temperature sensed by a temperature sensor. Then, the junction temperature of the second power semiconductor device is finally determined by adding the temperature prediction value of the heat sink to the junction temperature prediction value of the second power semiconductor device.

Description

Technical Field

[0001] The present invention relates to a method and system for estimating the junction temperature of a power semiconductor device of a power module, and more particularly, to a method and system for estimating the junction temperature of a power semiconductor device of a power module, which appropriately estimates the junction temperature of a power semiconductor device without an embedded temperature sensor even when an abnormality occurs in a cooling system that supplies coolant to the power module. Background Art

[0002] Generally, an inverter is required to convert direct current to generate three-phase alternating current to drive a motor. The inverter includes a power module having power semiconductor devices such as insulated gate bipolar transistors (IGBTs) and diodes that perform switching operations. The power semiconductor devices of the power module need to be managed at a predetermined maximum allowable temperature to prevent burnout and maintain a durable life.

[0003] Typically, the temperature of a power module is managed by applying a thermal model that estimates the junction temperature of the power semiconductor devices in the power module based on the switching frequency, current, voltage, etc. of the power semiconductor devices.

[0004] The technique of estimating the junction temperature of a power semiconductor device using a conventional thermal model applies the temperature of a coolant supplied to cool the power semiconductor device to the estimation of the junction temperature. Since the coolant temperature is mainly measured by a coolant temperature sensor installed at the entrance of a coolant channel to which the coolant is supplied, when the coolant is not actually and properly delivered to the location where the power module is installed and the temperature of the power module increases, the junction temperature estimation value cannot correctly reflect such a temperature increase.

[0005] Specifically, the IGBT of a recently commercialized power semiconductor device may have an embedded temperature sensor to detect a temperature increase due to abnormal cooling liquid supply, but since a diode as another power semiconductor device has no embedded temperature sensor, even when the temperature increases due to abnormal cooling liquid supply, the junction temperature is predicted to be low, thereby causing burnout and reducing the durable life of the power module.

[0006] The above contents explained as background technology are only intended to help understand the background technology of the present invention, and are not intended to indicate that the present invention falls within the scope of the relevant technology known to those skilled in the art. Summary of the invention

[0007] Therefore, the present invention provides a method and system for estimating the junction temperature of a power semiconductor device of a power module, which can appropriately estimate the junction temperature of a power semiconductor device without an embedded temperature sensor even when an abnormality occurs in a cooling system that supplies coolant to the power module.

[0008] According to one aspect, the present invention provides a method for estimating the junction temperature of a power semiconductor device of a power module, the power module comprising: a first power semiconductor device, which is arranged adjacent to a heat sink for cooling and has a temperature sensor; and a second power semiconductor device, which is arranged adjacent to the first power semiconductor device and does not have a temperature sensor. The method may include calculating a junction temperature prediction value of the first power semiconductor device based on the power loss and thermal resistance of the first power semiconductor device; calculating a junction temperature prediction value of the second power semiconductor device based on the power loss and thermal resistance of the second power semiconductor device; calculating a temperature prediction value of the heat sink by subtracting the junction temperature prediction value of the first power semiconductor device from the sensed temperature sensed by the temperature sensor; and finally determining the junction temperature of the second power semiconductor device by adding the temperature prediction value of the heat sink to the junction temperature prediction value of the second power semiconductor device.

[0009] In an exemplary embodiment of the present invention, calculating the predicted junction temperature value of the first power semiconductor device may include: calculating the power loss of the first power semiconductor device; calculating the predicted junction temperature value of the first power semiconductor device by multiplying the power loss of the first power semiconductor device by a preset thermal resistance of the first power semiconductor device.

[0010] In addition, calculating the power loss of the first power semiconductor device may include calculating the power loss of the first power semiconductor device using a predetermined power loss calculation formula using a plurality of parameters related to the operation of the power module as variables. The thermal resistance of the first power semiconductor device may be predetermined by measuring a temperature change of the first power semiconductor device at each flow rate (liters / minute) of the coolant flowing through the heat sink.

[0011] In an exemplary embodiment of the present invention, calculating the predicted junction temperature value of the second power semiconductor device may include: calculating the power loss of the second power semiconductor device; calculating the predicted junction temperature value of the second power semiconductor device by multiplying the power loss of the second power semiconductor device by a preset thermal resistance of the second power semiconductor device.

[0012] Calculating the power loss of the second power semiconductor device may include: calculating the power loss of the second power semiconductor device using a predetermined power loss calculation formula using a plurality of parameters related to the operation of the power module as variables. In addition, the thermal resistance of the second power semiconductor device may be predetermined by measuring the temperature change of the second power semiconductor device at each flow rate (liters / minute) of the coolant flowing through the heat sink.

[0013] The method for estimating the junction temperature of a power semiconductor device of a power module may further include: if the junction temperature of the second power semiconductor device finally determined is greater than a preset reference value, de-rating or stopping the operation of the power module. The first power semiconductor device may be an IGBT, and the second power semiconductor device may be a diode.

[0014] According to another aspect, the present invention provides a system for estimating the junction temperature of a power semiconductor device of a power module, the power module comprising a first power semiconductor device and a second power semiconductor device, the first power semiconductor device being arranged adjacent to a heat sink for cooling and having a temperature sensor, the second power semiconductor device being arranged adjacent to the first power semiconductor device and not having a temperature sensor. The system may include: a memory configured to store a predetermined power loss calculation formula for each of the first power semiconductor device and the second power semiconductor device using a plurality of parameters related to the operation of the power module as variables, and to store a thermal resistance of each of the first power semiconductor device and the second power semiconductor device, the thermal resistance of each of the first power semiconductor device and the second power semiconductor device being predetermined by a method of measuring a temperature change of the first power semiconductor device and the second power semiconductor device for each flow rate (liter / minute) of a coolant flowing through the heat sink; and a processor configured to determine the junction temperature of the second power semiconductor device based on the information stored in the memory and the sensed temperature of the temperature sensor.

[0015] The processor may be configured to receive parameters related to the operation of the power module to calculate the power loss of the first power semiconductor device, and calculate the predicted junction temperature value of the first power semiconductor device based on the power loss of the first power semiconductor device and the thermal resistance of the first power semiconductor device. In addition, the processor may be configured to receive parameters related to the operation of the power module to calculate the power loss of the second power semiconductor device, and calculate the predicted junction temperature value of the second power semiconductor device based on the power loss of the second power semiconductor device and the thermal resistance of the second power semiconductor device.

[0016] In addition, the processor can be configured to calculate a temperature prediction value of the heat sink by subtracting a junction temperature prediction value of the first power semiconductor device from a sensed temperature sensed by a temperature sensor set in the first power semiconductor device, and finally determine the junction temperature of the second power semiconductor device by adding the temperature prediction value of the heat sink to the junction temperature prediction value of the second power semiconductor device.

[0017] In an exemplary embodiment of the present invention, the memory may be configured to store a preset reference value for comparison with the second power semiconductor device, and the processor may be configured to: if the junction temperature of the second power semiconductor device finally determined is greater than the preset reference value, the processor derates the operation of the power module or stops the operation of the power module. The first power semiconductor device may be an IGBT, and the second power semiconductor device may be a diode.

[0018] A method and system for estimating the junction temperature of a power semiconductor device of a power module can derive the temperature of a heat sink used to cool the power module by utilizing a thermal model of the power semiconductor device embedded with a temperature sensor and the sensed temperature of the temperature sensor, and utilize the derived heat sink temperature to predict the junction temperature of the power semiconductor device without an embedded temperature sensor, thereby improving the accuracy of predicting the junction temperature of the power semiconductor device without an embedded temperature sensor.

[0019] Specifically, the method and system for estimating the junction temperature of a power semiconductor device of a power module can predict the junction temperature of a power semiconductor device without an embedded temperature sensor, even if a problem occurs in the system for supplying coolant to the heat sink of the power module, making it impossible to accurately detect the temperature of the heat sink and thus unable to accurately confirm that the junction temperature of the power semiconductor device is too high, thereby preventing the device from being damaged or the device from ceasing to operate due to excessively high junction temperature and preventing the device from being reduced in service life.

[0020] Effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood from the following description by those skilled in the art to which the present invention pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and other advantages of the present invention will be more clearly understood through the following detailed description presented in conjunction with the accompanying drawings, in which:

[0022] Figure 1 is a plan view showing a portion of a power module to which various exemplary embodiments of the present invention are applied.

[0023] Figure 2 is a cross-sectional view showing an example of a portion of a power module to which various exemplary embodiments of the present invention are applied.

[0024] Figure 3 is a schematic diagram briefly showing a power module cooling system to which various exemplary embodiments of the present invention are applied.

[0025] Figure 4 is a block diagram illustrating a system for estimating a junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention.

[0026] Figure 5 is a flow chart illustrating a method for estimating a junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0027] It should be understood that the terms "vehicle" or "vehicle-based" or other similar terms used herein include general motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, various boats, ships and aircraft, etc., and include hybrid vehicles, electric vehicles, internal combustion engine vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from non-fossil energy).

[0028] Although the exemplary embodiments are described as using multiple units to perform the exemplary processes, it should be understood that the exemplary processes can also be performed by one or more modules. In addition, it should be understood that the term "controller / control unit" refers to a hardware device including a memory and a processor, and is specifically programmed to perform the processes described herein. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more processes further described below.

[0029] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "one", "an" and "said" are intended to also include plural forms, unless the context clearly states otherwise. It will also be understood that when the terms "include" and / or "comprising" are used in this specification, it indicates the presence of the features, numerical values, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, numerical values, steps, operations, elements, components and / or their groups. As used herein, the term "and / or" includes any and all combinations of one or more related enumeration items.

[0030] Unless otherwise stated or apparent from the context, the term "about" as used herein is understood to be within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" may be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of a specified value. Unless the context clearly indicates otherwise, all numerical values ​​provided herein are modified by the term "about".

[0031] Hereinafter, a method and system for estimating a junction temperature of a power semiconductor device of a power module according to various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0032] First, the structure of a power module to which various exemplary embodiments of the present invention are applied will be briefly described. Figure 1 is a plan view showing a portion of a power module to which various exemplary embodiments of the present invention are applied, Figure 2 is a cross-sectional view showing an example of a portion of a power module to which various exemplary embodiments of the present invention are applied.

[0033] refer to Figure 1 and Figure 2 , the power module 10 may include a plurality of IGBTs 11 and diodes 12 arranged on a substrate 13. Figure 1 and 2 Although not shown in the figure, the IGBT 11 and the diode 12 can be electrically connected to each other through a power line, which is implemented as a conductive pattern formed on the substrate 13, etc., and the power line can exchange power with other external electrical components through a power conductor 14, such as Figure 2 In addition, although not shown, the IGBT 11 and the diode 12 may be connected to the signal wire 15 via wiring to receive a signal for control from the outside.

[0034] The power module 10 may be disposed adjacent to the heat sink 20 so as to be in close or abutting contact with the base plate 13 below the base plate 13. In addition, a cooling liquid for lowering the temperature of the power module may flow through the heat sink 20. Figure 2 The heat sink 20 is shown in FIG. 1 , and a heat sink 20 is installed under the substrate 13, but the cooling structure of various methods known in the art and the present invention is not limited to Figure 2 The flow rate (L / min) and temperature of the coolant flowing to the heat sink 20 can be applied to predict the junction temperature of the first power semiconductor device and the second power semiconductor device in the power module 10, which will be described below.

[0035] exist Figure 1 and Figure 2, the IGBT 11 corresponding to the first power semiconductor device is a device having a temperature sensor 111 therein. Therefore, the junction temperature of the first power semiconductor device may be a sensed value sensed by the temperature sensor 111. In addition, the diode 12 corresponding to the second power semiconductor device is a device having no temperature sensor embedded therein, and the junction temperature needs to be estimated by calculation using a temperature estimation technique. In conventional junction temperature estimation techniques, the temperature of the coolant flowing through the heat sink 20 is used to calculate the junction temperature, and if the calculated coolant temperature used to estimate the junction temperature is different from the actual temperature of the coolant flowing through the contact area between the power module and the heat sink, the estimation of the junction temperature of the second power semiconductor device may be inaccurate.

[0036] Figure 3 Schematic diagram briefly showing a power module cooling system to which various exemplary embodiments of the present invention are applied. Figure 3 As shown, the power module 10 may be disposed inside the housing 40 together with other components for performing related functions, and the heat sink 20 may be disposed in contact with the power module 10 inside the housing 40. The coolant flowing through the heat sink 20 may be supplied from a coolant inlet 50 outside the housing 40, and a water temperature sensor 30 configured to measure the coolant temperature may be located outside the housing 40, corresponding to a point where the housing 40 intersects with the coolant inlet 50. In other words, the water temperature sensor 30 may be configured to sense the coolant temperature immediately before the coolant is to be introduced into the housing 40.

[0037] The coolant temperature sensing structure may be configured to sense the coolant temperature as being substantially lower than the temperature of the actual coolant in the radiator 20 even when the coolant is not smoothly supplied to the radiator 20. Therefore, if the coolant temperature sensed by the water temperature sensor 30 is used to estimate the junction temperature of the second power semiconductor device of the power module 10 as described above, the estimated junction temperature may be calculated as a value lower than the actual junction temperature, and therefore, failure to predict an increase in the junction temperature may cause serious problems such as device burnout or operational errors of the entire system.

[0038] Various exemplary embodiments of the present invention provide a technique for more accurately estimating the temperature of the coolant in the heat sink 20 adjacent to the power module 10 using the junction temperature of a power semiconductor device having an embedded temperature sensor, thereby more accurately estimating the junction temperature of another power semiconductor device without an embedded temperature sensor.

[0039] Figure 4 is a block diagram showing a system for estimating the junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention. Figure 4According to an exemplary embodiment of the present invention, a system for estimating the junction temperature of a power semiconductor device may include a memory 100 and a processor 200, the memory 100 being configured to store data required for calculations used to estimate and determine the junction temperature of the power semiconductor device or to determine whether a power module is derated; the processor 200 being configured to perform calculations or processes for receiving data stored in the memory 100 and operating parameters of the power module to estimate the junction temperature of the power semiconductor device and determine whether to perform derate.

[0040] The memory 100 may be configured to store previous data required to estimate the junction temperature of the first power semiconductor device and the second power semiconductor device through a thermal model. For example, the memory 100 may be configured to store a calculation formula and thermal resistance required to calculate the power loss of the first power semiconductor device and the second power semiconductor device. The processor 200 may be configured to perform calculations and data processing for estimating the junction temperature of the first power semiconductor device and the second power semiconductor device through a thermal model, estimating the temperature of the heat sink, and thereby determining the junction temperature of the second power semiconductor device. In addition, the processor 200 may be configured to perform a determination for determining whether the power module is derated or stopped based on the determined junction temperature of the second power semiconductor device.

[0041] Each of the functional blocks 210 to 270 constituting the processor 200 is a unit configured to perform calculations, processing, determinations, etc. implemented in the processor 200, and its operation will be clearly described through the following description of the method for estimating the junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention.

[0042] Figure 5 is a flow chart illustrating a method for estimating the junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention. Figure 4 and Figure 5 , a method for estimating the junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention may start by calculating the power loss of a first power semiconductor device and the power loss of a second power semiconductor device in a first power loss calculation unit 210 and a second power loss calculation unit 230, respectively (S11, S21).

[0043] The power loss of each power semiconductor device can be classified into conduction loss occurring when current is turned on and switching loss occurring when switching, and each loss can be calculated by a preset conduction loss calculation formula and a switching loss calculation formula. The conduction loss calculation formula and the switching loss calculation formula can be pre-stored in the memory 100.

[0044] The calculation formula for calculating the power loss of the power semiconductor device can be preset based on various parameters according to the characteristics of the inverter of the type to which the power module (IGBT, diode, etc.) is applied, and is determined by various methods according to the company that manufactures the power module or the company that manufactures products such as vehicles by applying the power module. Specifically, as parameters mainly used to calculate the conduction loss or switching loss, the voltage and current provided by the power module, the switching frequency of the power semiconductor device, etc. can be considered.

[0045] For example, the first power loss calculation unit 210 can be configured to read a calculation formula for calculating the power loss of a first power semiconductor device such as an IGBT from the memory 100, receive the voltage and current of the power module, the switching frequency of the first power semiconductor device, etc. from an external sensor to calculate the conduction loss and switching loss of the first power semiconductor device, and then add the two values ​​to calculate the power loss of the first power semiconductor device.

[0046] The second power loss calculation unit 230 may also be configured to calculate the power loss of the second power semiconductor device in a similar manner. As described above, since the calculation formula for calculating the power loss of the power semiconductor device can be determined in a unique manner according to the manufacturer of the power semiconductor device or the power module or the manufacturer of the vehicle or the like using the power module, a detailed description of the specific form of the calculation formula will be omitted.

[0047] Subsequently, the first junction temperature calculation unit 220 and the second junction temperature calculation unit 240 can be respectively configured to: calculate the junction temperature prediction value of the first power semiconductor device by multiplying the power loss of the first power semiconductor device obtained by the calculation formula by the thermal resistance of the first power semiconductor device pre-stored in the memory 100, and calculate the junction temperature prediction value of the second power semiconductor device by multiplying the power loss of the second power semiconductor device obtained by the calculation formula by the thermal resistance of the second power semiconductor device pre-stored in the memory 100 (S12, S22).

[0048] The thermal resistance of the power semiconductor device can be determined based on the inherent characteristics of the power module including the power semiconductor device and the heat dissipation characteristics of the cooler. Therefore, the thermal resistance of the power semiconductor device can be determined in advance by an experimental method through a drive test of a target (e.g., a motor) powered by the power module, and the thermal resistance obtained in advance by the experimental method can be stored in the memory 100.

[0049] The method for predetermining thermal resistance is briefly described as follows. The method may include: driving the power module by predetermining the parameters of the power module for obtaining the power loss of the power semiconductor device (e.g., the input voltage, input current and switching frequency of the power semiconductor device), and obtaining the temperature of the power semiconductor device in the power module through a temperature sensor (e.g., a thermal imaging camera, etc.) to confirm the change trend of the obtained temperature, thereby determining the thermal resistance. For example, when power loss occurs in each power semiconductor device, due to the characteristics of thermal resistance, the temperature of each power semiconductor device may increase to reach a saturation state. At this time, the temperature change value (e.g., the final temperature in the saturation state and the starting temperature before the current is applied) can be more easily confirmed by applying an experimental method through a thermal imaging camera.

[0050] Therefore, the thermal resistance value can be calculated from the temperature change value of the power semiconductor device obtained by the thermal imaging camera and the power loss value obtained by the value of the input parameters (e.g., current, voltage, and switching frequency) of the power semiconductor device during the experiment. In other words, the thermal resistance value in the experiment can be determined by dividing the temperature change value by the power loss calculated by the parameters.

[0051] In addition, since the thermal resistance value can be changed based on the heat dissipation characteristics, it is necessary to reflect the flow rate (liters per minute) of the coolant flowing through the heat sink 20 to determine the thermal resistance. Therefore, the thermal resistance experiment can be performed by applying the above input parameters while changing the flow rate (liters per minute, LPM) of the coolant to obtain the thermal resistance corresponding to the flow rate (liters per minute) of each coolant. The thermal resistance data corresponding to the flow rate (liters per minute) of the coolant can be pre-stored in the memory 100, and the first junction temperature calculation unit 220 and the second junction temperature calculation unit 240 can be configured to: receive information about the flow rate (liters per minute) of the coolant from a flow meter (not shown) provided in the coolant supply system that supplies the coolant to the heat sink 20, read the thermal resistance corresponding thereto from the memory 100, and then calculate the junction temperature prediction value of the first power semiconductor device and the second power semiconductor device.

[0052] Subsequently, the heat sink temperature calculation unit 250 may be configured to calculate a predicted temperature value of the heat sink by subtracting a predicted junction temperature value of the first power semiconductor device calculated by the first junction temperature calculation unit 220 from a sensed temperature sensed by the temperature sensor 111 embedded in the first power semiconductor device ( S31 ).

[0053] The sensed temperature sensed by the temperature sensor 111 embedded in the first power semiconductor device may be a temperature value closest to the actual junction temperature of the first power semiconductor device. The junction temperature of each power semiconductor device may be determined by adding the cooling temperature of the heat sink 20 to the heating temperature according to each operation. Since the temperature prediction value calculated by the thermal model in consideration of the power loss and thermal resistance of the first power semiconductor device does not consider the temperature of the heat sink 20, the temperature of the heat sink 20 may be estimated by subtracting the junction temperature prediction value of the first power semiconductor device calculated by the first junction temperature calculation unit 220 from the sensed temperature of the temperature sensor 111 corresponding to the actual junction temperature of the first power semiconductor device.

[0054] Subsequently, the temperature determination unit 260 may be configured to finally determine the junction temperature of the second power semiconductor device by adding the heat sink temperature prediction value calculated by the heat sink temperature calculation unit 250 to the junction temperature prediction value of the second power semiconductor device without an embedded temperature sensor (S32). The method for estimating the junction temperature of a power semiconductor device according to an exemplary embodiment of the present invention may further include determining whether the power module is derated or stopped based on the junction temperature of the second power semiconductor device finally determined by the power module operation determination unit 270 (S33).

[0055] For example, at least one reference value that can be compared with the finally determined junction temperature of the second power semiconductor device can be stored in the memory 100. The finally determined junction temperature of the second power semiconductor device can then be compared with the stored first reference value, and in response to determining that the finally determined junction temperature of the second power semiconductor device is greater than the first reference value, the method can then include performing a derating that forcibly reduces the performance of the power module. The reference value can be a preset value for reference to determine whether to perform derating.

[0056] As another example, the power module operation determination unit 270 may be configured to compare the finally determined junction temperature of the second power semiconductor device with a stored second reference value, and in response to determining that the finally determined junction temperature of the second power semiconductor device is greater than the second reference value, stop the operation of the power module. Specifically, the second reference value may be a preset value for reference in determining whether the operation of the power module is stopped, and may be a value greater than the first reference value.

[0057] As another example, a third reference value less than the first reference value may be stored, and derating may be performed by comparison with the first reference value, and then, if the junction temperature of the second power semiconductor device determined by performing these steps (S11, S12, S21, S22, S31, and S32) again is less than the third reference value, the derating may be released so that the power module also operates normally. The third reference value may be a predetermined value for returning the power module to normal operation.

[0058] As described above, the method and system for estimating the junction temperature of a power semiconductor device of a power module according to various exemplary embodiments of the present invention can derive the temperature of a heat sink for cooling the power module by utilizing a thermal model of the power semiconductor device embedded with a temperature sensor and the sensed temperature of the temperature sensor, and use the derived temperature of the heat sink to predict the junction temperature of the power semiconductor device without an embedded temperature sensor, thereby improving the accuracy of predicting the junction temperature of the power semiconductor device without an embedded temperature sensor.

[0059] Specifically, the method and system for estimating the junction temperature of a power semiconductor device of a power module can predict the junction temperature of a power semiconductor device without an embedded temperature sensor, even if a problem occurs in the system for supplying coolant to the heat sink of the power module, making it impossible to accurately detect the temperature of the heat sink and thus unable to accurately confirm that the junction temperature of the power semiconductor device is too high, thereby preventing the device from being damaged or ceasing to work due to excessively high junction temperature and reducing the durability of the device.

[0060] While specific exemplary embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various modifications and changes may be made to the present invention without departing from the technical spirit of the present invention as provided by the appended claims.

Claims

1. A method for estimating a junction temperature of a power semiconductor device of a power module, the power module comprising a first power semiconductor device and a second power semiconductor device, the first power semiconductor device being arranged adjacent to a heat sink for cooling and having a temperature sensor, the second power semiconductor device being arranged adjacent to the first power semiconductor device and not having a temperature sensor, the method comprising: Calculating, by the processor, a predicted junction temperature value of the first power semiconductor device based on the power loss and thermal resistance of the first power semiconductor device; Calculating, by the processor, a predicted junction temperature value of the second power semiconductor device based on the power loss and thermal resistance of the second power semiconductor device; calculating, by the processor, a predicted temperature value of the heat sink by subtracting a predicted junction temperature value of the first power semiconductor device from a sensed temperature sensed by the temperature sensor; The processor finally determines the junction temperature of the second power semiconductor device by adding the temperature prediction value of the heat sink to the junction temperature prediction value of the second power semiconductor device; In response to determining that the finally determined junction temperature of the second power semiconductor device is greater than a preset reference value, the processor derates the operation of the power module or stops the operation of the power module.

2. The method according to claim 1, wherein: Calculating the predicted value of the junction temperature of the first power semiconductor device includes: calculating, by the processor, a power loss of the first power semiconductor device; The processor calculates a predicted junction temperature value of the first power semiconductor device by multiplying the power loss of the first power semiconductor device by a preset thermal resistance of the first power semiconductor device.

3. The method according to claim 2, wherein: Calculating the power loss of the first power semiconductor device includes calculating the power loss of the first power semiconductor device using a predetermined power loss calculation formula using a plurality of parameters related to the operation of the power module as variables.

4. The method according to claim 2, wherein: The thermal resistance of the first power semiconductor device is predetermined by measuring a temperature change of the first power semiconductor device for each flow rate of the cooling fluid flowing through the heat sink.

5. The method according to claim 1, wherein: Calculating the predicted value of the junction temperature of the second power semiconductor device includes: calculating, by the processor, a power loss of the second power semiconductor device; The processor calculates a predicted junction temperature value of the second power semiconductor device by multiplying the power loss of the second power semiconductor device by a preset thermal resistance of the second power semiconductor device.

6. The method according to claim 5, wherein: Calculating the power loss of the second power semiconductor device includes calculating the power loss of the second power semiconductor device using a predetermined power loss calculation formula using a plurality of parameters related to the operation of the power module as variables.

7. The method according to claim 5, wherein: The thermal resistance of the second power semiconductor device is predetermined by measuring the temperature change of the second power semiconductor device for each flow rate of the cooling fluid flowing through the heat sink.

8. The method according to claim 1, wherein: The first power semiconductor device is an insulated gate bipolar transistor, and the second power semiconductor device is a diode.

9. A system for estimating a junction temperature of a power semiconductor device of a power module, the power module comprising a first power semiconductor device and a second power semiconductor device, the first power semiconductor device being arranged adjacent to a heat sink for cooling and having a temperature sensor, the second power semiconductor device being arranged adjacent to the first power semiconductor device and not having a temperature sensor, the system comprising: a memory configured to store a predetermined power loss calculation formula for each of the first power semiconductor device and the second power semiconductor device using a plurality of parameters as variables, and to store a thermal resistance of each of the first power semiconductor device and the second power semiconductor device, the thermal resistance of each of the first power semiconductor device and the second power semiconductor device being predetermined by a method of measuring temperature changes of the first power semiconductor device and the second power semiconductor device at respective flow rates of a coolant flowing through a heat sink; as well as a processor configured to determine a junction temperature of the second power semiconductor device based on information stored in the memory and a sensed temperature of the temperature sensor, Wherein, the processor is configured as follows: receiving parameters related to the operation of the power module to calculate the power loss of the first power semiconductor device, and calculating a junction temperature prediction value of the first power semiconductor device based on the power loss of the first power semiconductor device and the thermal resistance of the first power semiconductor device, receiving parameters related to the operation of the power module to calculate the power loss of the second power semiconductor device, and calculating a junction temperature prediction value of the second power semiconductor device based on the power loss of the second power semiconductor device and the thermal resistance of the second power semiconductor device, Calculating a predicted temperature value of the heat sink by subtracting a predicted junction temperature value of the first power semiconductor device from a sensed temperature sensed by a temperature sensor disposed in the first power semiconductor device; Finally determining the junction temperature of the second power semiconductor device by adding the predicted value of the temperature of the heat sink to the predicted value of the junction temperature of the second power semiconductor device; In response to determining that the finally determined junction temperature of the second power semiconductor device is greater than a preset reference value, the operation of the power module is derated or stopped.

10. The system for estimating the junction temperature of a power semiconductor device of a power module according to claim 9, wherein: The memory is configured to store a preset reference value for comparison with the second power semiconductor device.

11. The system for estimating the junction temperature of a power semiconductor device of a power module according to claim 9, wherein: The first power semiconductor device is an insulated gate bipolar transistor, and the second power semiconductor device is a diode.

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