A system for detecting cooling abnormalities in a power converter, a computing device for detection, and a method for detection.

Abstract

The present invention aims to provide a technology for detecting abnormalities in the semiconductor module, TIM, or cooler during the operation of a power conversion device, and for identifying the location of the abnormality. [Solution] The system for detecting cooling abnormalities in a power conversion device of the present invention comprises a power conversion device and a computing device. The computing device includes a thermal resistance prediction unit that calculates the thermal resistance between the semiconductor module and the cooler, and the thermal resistance between the cooler and the cooler, based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the cooler during actual operation, and the heat generation history of the semiconductor module during actual operation. The computing device also includes an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the cooler, the temperature history of the cooler during actual operation, and the heat generation history of the semiconductor module during actual operation.

Description

Technical Field

[0001] The present invention relates to a cooling abnormality detection system, an arithmetic device for detection, and a detection method for detecting a cooling abnormality of a power conversion device that supplies power to a motor or the like mounted on a railway vehicle.

Background Art

[0002] In a railway vehicle, generally, a power conversion device for controlling the power supplied to a driving motor is mounted under the floor. The power conversion device is provided with a power converter composed of semiconductor elements that perform current switching to perform DC / AC power conversion. In semiconductor elements, heat is generated during energization and switching. When the semiconductor elements become high temperature due to this heat, there is concern about a decrease in conversion efficiency and deterioration of the elements, so it is necessary to cool and control the semiconductor elements so that they are within a predetermined temperature range.

[0003] As a cooling method for the power conversion device, a cooler such as a heat sink is brought into contact with the heat dissipation base of a power semiconductor module (hereinafter referred to as a semiconductor module) incorporating semiconductor elements via a TIM (Thermal Interface Material) or the like, and a cooling method by an air cooling method or a water cooling method is used. When an abnormality occurs in these cooling systems and the cooling efficiency decreases, output limitation and maintenance of the device become necessary. In order to shorten the downtime and maintenance period of the device, a cooling abnormality detection system that can identify the presence or absence of a cooling abnormality and the location where the abnormality occurs during vehicle operation is desired.

[0004] As an example of a cooling abnormality detection system, Patent Document 1 is cited here. Patent Document 1 discloses a method of detecting the temperature of a heat generating component, the temperature of a cooling component, and the power consumption of a heat generating component, calculating the thermal resistance value of the contact portion between the heat generating component and the cooling component, and detecting an abnormality in the contact portion between the heat generating component and the cooling component based on the thermal resistance value.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-72473 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, according to the technology described in Patent Document 1, abnormalities in the contact area between heat-generating components and cooling components can only be detected individually. Therefore, there is a problem in that it cannot detect abnormalities such as increased heat loss of semiconductor elements or decreased cooling efficiency due to fouling or deterioration of the cooler, which are common cooling abnormalities in power conversion devices.

[0007] Furthermore, power converters for railway vehicles, for example, require multiple semiconductor modules to be arranged in series and parallel to handle multiphase AC, high current, and high voltage, resulting in a large number of modules. For this reason, a system capable of detecting abnormalities in the semiconductor modules and the heat dissipation paths for each phase, i.e., localized abnormalities, is desirable.

[0008] Furthermore, in order to shorten the downtime and maintenance period of the equipment after a cooling anomaly occurs, a system that can detect cooling anomalies while the power converter is in operation and identify the location of the anomaly is desirable.

[0009] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a technology that enables the detection of abnormalities in the semiconductor module, TIM, or cooler during the operation of a power conversion device, and the identification of the location where the abnormality occurred. [Means for solving the problem]

[0010] To solve the above problems, one representative system for detecting cooling abnormalities in a power conversion device of the present invention comprises a power conversion device including a semiconductor module, a semiconductor module internal temperature detection unit, a cooler temperature detection unit, and a refrigerant temperature detection unit, and a calculation device that outputs an abnormality determination result for the power conversion device. The calculation device comprises a thermal resistance prediction unit that calculates the thermal resistance between the semiconductor module and the cooler, and the thermal resistance between the cooler and the refrigerant, based on the semiconductor module internal temperature history during actual operation, the cooler temperature history during actual operation, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation, and an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation. [Effects of the Invention]

[0011] According to the present invention, it is possible to detect a cooling abnormality in a power converter while the power converter is in operation, and to identify which semiconductor module or phase of the conversion circuit the abnormality occurred on the heat dissipation path, and further, whether it occurred in the semiconductor module, TIM, cooler, or refrigerant. Other issues, configurations, and effects not mentioned above will be clarified by the description of the embodiments for carrying out the invention below. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of an example of a system for detecting cooling abnormalities in a power converter for railway vehicles according to Example 1. [Figure 2] Figure 2 shows an example of the structure of a power converter for railway vehicles according to Example 1. [Figure 3] Figure 3 is a block diagram of a system for detecting cooling abnormalities in a power converter for railway vehicles according to Example 1. [Figure 4] Figure 4 shows an example of the processing flow of the abnormality determination unit of the system for detecting cooling abnormalities in a power converter for railway vehicles according to Embodiment 1. [Figure 5]FIG. 5 is a diagram showing an example of the structure of the power conversion device for railway vehicles according to Embodiment 2. [Figure 6] FIG. 6 is a diagram showing an example of the structure of the power conversion device for railway vehicles according to Embodiment 3. [Figure 7] FIG. 7 is a diagram showing an example of the structure of the power conversion device for railway vehicles according to Embodiment 4. [Figure 8] FIG. 8 is a diagram showing an example of the processing flow of the abnormality determination unit of the system for detecting a cooling abnormality of the power conversion device for railway vehicles according to Embodiment 4. MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings by way of examples. Note that the present invention is not limited by these examples. Also, in the description of the drawings, the same parts are denoted by the same reference numerals.

[0014] (Embodiment 1) (System Configuration) First, Embodiment 1 will be described. FIG. 1 is a schematic diagram of an example of a system for detecting a cooling abnormality of the power conversion device for railway vehicles according to Embodiment 1. Note that in FIG. 1, components of the railway system that are not related to the present invention are omitted.

[0015] Under the floor of the railway vehicle 1, a power conversion device 2, a bogie 3, a motor 4, a transmission device 5, and a vehicle information device 6 are installed. Also, the arithmetic device 12 may be installed on the vehicle side or at a location separate from the railway vehicle 1 (for example, on the ground side).

[0016] The power conversion device 2 supplies AC power 7 to the motor 4 installed on the bogie 3 to drive the motor 4. Also, the power conversion device 2 transmits the in-service semiconductor module internal temperature history 8 (T1), the in-service cooler temperature history 9 (T2), and the in-service refrigerant temperature history 10 (T3) to the transmission device 5.

[0017] The vehicle information device 6 transmits the in-service operation history 17 to the transmission device 5.

[0018] The transmission device 5 transmits the in-operation semiconductor module internal temperature history 8, the in-operation cooler temperature history 9, the in-operation refrigerant temperature history 10, and the in-operation operation history 17 to the arithmetic unit 12.

[0019] The arithmetic unit 12 outputs the abnormality determination result 11 and transmits it to the transmission device 5. The transmission device 5 transmits the abnormality determination result 11 to the driver or conductor inside the vehicle, or to the station or operation management center outside the vehicle. Further, the arithmetic unit 12 is installed on the ground side or on the vehicle side. When installed on the ground side, data between the arithmetic unit and the power conversion device is transmitted and received via the transmission device 5. On the other hand, when installed on the vehicle side such as under the floor of the railway vehicle 1, the in-operation semiconductor module internal temperature history 8, the in-operation cooler temperature history 9, the in-operation refrigerant temperature history 10, and the in-operation operation history 17 may be received wired directly from the power conversion device 2 and the vehicle information device 6 without going through the transmission device 5.

[0020] Furthermore, the in-operation semiconductor module internal temperature history 8, the in-operation cooler temperature history 9, and the in-operation refrigerant temperature history 10 may be transmitted to the transmission device 5 via the vehicle information device 6. Also, the in-operation refrigerant temperature history 10 may be transmitted to the transmission device 5 without going through the power conversion device 2, for example, the temperature history of the outside air taken into the air conditioner for passengers in vehicle 2. The transmission path is not limited. Also, the power conversion device 2, the vehicle information device 6, and the transmission device 5 may be configured as one integrated device.

[0021] (Power Conversion Device) Figure 2 shows an example of the structure of a power converter for a railway vehicle according to Embodiment 1. The power converter 2 has one or more semiconductor modules 31 (sometimes simply called modules) and a cooler. The semiconductor modules are installed on one side (also called the mounting surface) of the heat receiving block 32 of the cooler via a TIM (not shown). On the side of the heat receiving block 32 opposite to the mounting surface, a cooling means such as cooling fins 33 is mounted, which is cooled by a fan or cooling airflow 34 generated by the train's movement. Figure 2(a) is a perspective view of the semiconductor module 31 and the heat receiving block 32 from the direction normal to the mounting surface. Figure 2(b) is a perspective view of the semiconductor module 31, the heat receiving block 32 and the cooling fins 33 from a direction parallel to the mounting surface.

[0022] Each semiconductor module 31 is equipped with a semiconductor module internal temperature detection unit 13 corresponding to the semiconductor module 31. Similarly, the heat receiving block 32 is equipped with a cooler temperature detection unit 14 corresponding to each semiconductor module 31. In addition, a refrigerant temperature detection unit 15 is installed near the cooling fins 33. The semiconductor module internal temperature detection unit 13 is provided, for example, on the heat dissipation base or insulating substrate of the semiconductor module 31. When there are multiple semiconductor modules, it is desirable that the distance relationship between the semiconductor module internal temperature detection unit 13 and the cooler temperature detection unit 14, which are provided for the same semiconductor module, be equivalent to that between different modules. In this case, the distance relationship between the heat-generating points of each module and the semiconductor module internal temperature detection unit 13 and the cooler temperature detection unit 14 will be equivalent, allowing for a side-by-side comparison of the temperature and thermal resistance of each module, thereby reducing the computational load for abnormality detection. Alternatively, a cooler temperature detection unit 14 that is common to different semiconductor modules 31 may be provided.

[0023] The refrigerant temperature detection unit 15 may be installed, for example, near or on the cooling fins. Alternatively, it may refer to the inlet air temperature of other devices installed in the vehicle, such as the inlet air temperature for the passenger compartment air conditioning, or meteorological data. Here, if multiple rows of modules are installed in the direction of the cooling airflow 34, a refrigerant temperature detection unit 15 corresponding to each module row may be provided in order to obtain the refrigerant temperature history 10(T3) during actual operation for each module row. Alternatively, the refrigerant temperature detection unit 15 may be provided only on the upwind side, and the refrigerant temperature history 10(T3) during actual operation for the other rows may be estimated from the heat generation history 18(P) of the semiconductor modules during actual operation and the refrigerant flow rate.

[0024] For the temperature detection units 13-15, for example, thermistors and thermocouples may be used. In addition, methods for installing the temperature detection units may include soldering, fixing with adhesive or tape, or embedding them in the heat dissipation base of the semiconductor module 31 or in holes or grooves in the heat receiving block.

[0025] (System block structure and processing flow) Figure 3 is a block diagram of a system for detecting cooling abnormalities in a power converter for railway vehicles according to Example 1. Some components have been omitted.

[0026] The power converter 2 is equipped with a semiconductor module internal temperature detection unit 13, a cooler temperature detection unit 14, and a refrigerant temperature detection unit 15. These units acquire the semiconductor module internal temperature history 8(T1), the cooler temperature history 9(T2), and the refrigerant temperature history 10(T3) during actual operation, respectively, and transmit them to the computing unit 12 via the transmission device 5. The vehicle information device 6 also acquires the operation history 17 during actual operation and transmits it to the computing unit 12 via the transmission device 5.

[0027] The computing unit 12 has a heat generation prediction unit and calculates the heat generation history 18(P) of the semiconductor module during actual operation based on the operation history 17 during actual operation. The computing unit 12 also has a thermal resistance prediction unit and calculates the thermal resistance 19(R12) between the semiconductor module and the cooler, and the thermal resistance 20(R23) between the cooler and the cooler, based on the internal temperature history 8(T1) of the semiconductor module during actual operation, the cooler temperature history 9(T2) of the cooler during actual operation, the coolant temperature history 10(T3) of the coolant during actual operation, and the heat generation history 18(P) of the semiconductor module during actual operation. The thermal resistance is predicted using, for example, the following equations (1) and (2).

number

number

[0028] The processing cycle in the arithmetic unit 12 is assumed to be a processing cycle that is executed at intervals of a certain amount of time, such as once a month, or once every three or six months.

[0029] Figure 4 shows an example of the processing flow of the abnormality determination unit of the system for detecting cooling abnormalities in a power converter for railway vehicles according to Embodiment 1. The abnormality determination unit 21 determines the location of the abnormality based on the thermal resistance 19 (R12) between the semiconductor module and the cooler, the thermal resistance 20 (R23) between the cooler and the refrigerant, the semiconductor module internal temperature history 8 (T1) during actual operation, the cooler temperature history 9 (T2) during actual operation, the refrigerant temperature history 10 (T3) during actual operation, and the heat generation history of the semiconductor module during actual operation 18 (P). In this determination, threshold values ​​are set for the thermal resistance R12, R23, temperature T3, and heat generation P to maintain the semiconductor element temperature below an acceptable value. The following describes the processing steps.

[0030] S401: Determine whether the thermal resistance 20 (R23) between the cooler and the coolant is "R23 > thermal resistance threshold". If yes, output abnormal mode 1: cooler abnormality and terminate processing. If no, proceed to S402.

[0031] S402: Determine whether the thermal resistance 19 (R12) between the semiconductor module and the cooler is "R12 > thermal resistance threshold". If yes, output abnormal mode 2: TIM abnormality and terminate processing. If no, proceed to S403.

[0032] S403: Determine whether the heat generation history 18(P) of the semiconductor module during actual operation is "P > heat generation threshold". If yes, output abnormal mode 3: abnormal heat loss of the semiconductor module and terminate processing. If no, proceed to S404.

[0033] S404: Determine whether the refrigerant temperature history 10 (T3) during actual operation is "T3 > temperature threshold". If yes, output abnormal mode 4: refrigerant temperature abnormality and terminate processing. If no, proceed to S405.

[0034] S405: Error Mode 5: Outputs other errors and terminates processing.

[0035] The following provides further details about each abnormal mode. Abnormal Mode 1 indicates a cooling system malfunction, which can be caused by reduced cooling efficiency due to contamination, damage, or deterioration of the cooling system. Specific examples include, in the case of air-cooled systems, contamination or clogging of fins and fin covers due to dust around the vehicle, and damage from flying debris. In the case of water-cooled systems, possible causes include refrigerant deterioration, and contamination or corrosion of the heat sink.

[0036] An abnormality in TIM mode 2 could be due to an increase in contact thermal resistance between the semiconductor module and the cooler, caused by TIM degradation. Specific phenomena could include, for example, deterioration of the TIM's thermal conductivity due to repeated thermal cycling, the formation of cracks or voids within the TIM, hardening of the TIM leading to decreased contact between the contact surfaces, and a pump-out phenomenon.

[0037] Abnormal Mode 3 in semiconductor modules can be attributed to the deterioration of internal components. Specific phenomena include deterioration of terminals and nodes, corrosion, increased contact resistance due to oxidation, increased internal resistance of semiconductor elements and wiring, and reduced performance due to deterioration of materials and structures within semiconductor elements.

[0038] Abnormal Mode 4 can indicate an abnormal refrigerant temperature, specifically refrigerant overheating. Possible causes include weather conditions, abnormal heat generation from nearby equipment, and deterioration or failure of cooling fans or pumps.

[0039] Other abnormalities in abnormal mode 5 include, for example, abnormal temperature detection values. Specific phenomena could include failure or delamination of the temperature detection unit.

[0040] Note that the order of the processing flow in Figure 4 is just one example, and the order of the flow may be changed depending on the frequency of abnormal mode occurrences, the driving area, and the characteristics of the vehicle.

[0041] Furthermore, while we have described the case where the temperature input value to the arithmetic unit 12 is obtained from the actual operating semiconductor module internal temperature history 8(T1), the actual operating cooler temperature history 9(T2), and the actual operating refrigerant temperature history 10(T3), for example, data from the time when the maximum value of the semiconductor module internal temperature, cooler temperature, refrigerant temperature, or the heat generation of the semiconductor module was recorded may also be used. Alternatively, data close to the heat generation amount and temperature conditions when defining the temperature threshold or thermal resistance threshold may be extracted and used. This makes it possible to reduce the amount of data transmitted from the transmission device 5 to the arithmetic unit 12 and to reduce the amount of calculation.

[0042] Finally, the effects of Example 1 will be explained. According to Example 1, abnormalities in the semiconductor module, TIM, and cooler can be detected while the railway vehicle is in operation, and it is possible to identify whether the abnormality occurred in the semiconductor module, TIM, cooler, or refrigerant. Furthermore, by providing temperature detection units that correspond to multiple mounted modules, it is possible to identify which semiconductor module's heat dissipation path is experiencing the abnormality. As a result, tests to identify the location of the abnormality become unnecessary, thus shortening the downtime and maintenance period of the equipment.

[0043] (Example 2) Next, we will describe Example 2, focusing on the differences from Example 1. Figure 5 shows an example of the structure of a power converter for railway vehicles according to Example 2. Multiple semiconductor modules 41, 42, and 43 are provided on the mounting surface of the heat receiving block 32, and cooling fins 33 are provided on the opposite side. The short sides of the semiconductor modules 41, 42, and 43 are arranged in a direction parallel to the cooling air, and multiple stages are arranged in the direction perpendicular to the direction of refrigerant flow. Multiple semiconductor modules (for example, 41a, 41b, and 41c) arranged in the direction of refrigerant flow constitute one phase of the conversion circuit. Figure 5(a) is a perspective view of the semiconductor modules 41, 42, and 43 and the heat receiving block 32 from the direction normal to the mounting surface. Figure 5(b) is a perspective view of the semiconductor modules 41, 42, and 43, the heat receiving block 32, and the cooling fins 33 from the short side parallel to the mounting surface. Furthermore, cooler temperature detection units 44, 45, and 46 are arranged on the heat receiving block 32 to correspond to each phase of the conversion circuit.

[0044] The computing unit 12 predicts the thermal resistance 19 (R12) between the semiconductor module and the cooler, and the thermal resistance 20 (R23) between the cooler and the cooler, for each phase of the conversion circuit, based on the actual operating temperature history 8 (T1a, T1b, T1c) of the semiconductor module, the actual operating temperature history 9 (T2) of the cooler, the actual operating temperature history 10 (T3) of the cooler, and the actual operating heat generation history 18 (P) of the semiconductor module. For example, for the phase of semiconductor module 41 (41a, 41b, 41c), the prediction is made using the following equations (3) to (5), based on the actual operating temperature history 8 (T1a, T1b, T1c) of the semiconductor module, the actual operating temperature history 9 (T2) of the cooler temperature detection unit 44, and the actual operating heat generation history 18 (P1) of the semiconductor module 41. Here, the subscripts a, b, and c indicate the respective semiconductor modules in the direction of the cooling airflow.

number

number

number

[0045] In the abnormality detection unit 21, threshold values ​​for each phase of the converter are set for the thermal resistances R12, R23, and T2, respectively, in order to maintain the semiconductor element temperature below the allowable value. The rest of the abnormality detection procedure is the same as in Example 1.

[0046] Of the abnormal modes, abnormal mode 1 and abnormal mode 2 enable abnormality detection at the phase level of the converter. The other abnormal modes are the same as in Example 1.

[0047] The method according to this embodiment 2 makes it possible to detect abnormalities in each semiconductor module, as well as abnormalities in the TIM and cooler on a phase-by-phase basis, when multiple semiconductor modules are connected in parallel to achieve multiphase AC in order to obtain high current and high voltage, and when a large number of semiconductor modules are installed. This configuration makes it easy to detect abnormalities when there are variations in the degradation of TIM and cooler between phases due to factors such as current imbalance, or when cooler damage varies in the height direction due to factors such as ballast collision. In addition, costs can be reduced by reducing the number of points in the cooler temperature detection unit.

[0048] (Example 3) Next, we will describe Example 3, focusing on the differences from Example 1. Figure 6 shows an example of the structure of a power converter for railway vehicles according to Example 3. Multiple semiconductor modules 41, 42, and 43 are provided on the ground surface of the heat receiving block 32, and cooling fins 33 are provided on the opposite side. The longitudinal directions of the semiconductor modules 41, 42, and 43 are oriented parallel to the cooling air, and multiple rows are arranged in the direction perpendicular to the refrigerant flow direction. Multiple semiconductor modules arranged perpendicular to the refrigerant flow direction (for example, 41a, 41b, and 41c) constitute one phase of the conversion circuit. Figure 6(a) is a perspective view of the semiconductor modules 41, 42, and 43 and the heat receiving block 32 from the direction normal to the installation surface. Figure 6(b) is a perspective view of the semiconductor modules 41, 42, and 43, the heat receiving block 32, and the cooling fins 33 from the longitudinal direction parallel to the installation surface. Furthermore, cooler temperature detection units 44, 45, and 46 are arranged on the heat receiving block 32 to correspond to each phase of the conversion circuit.

[0049] The calculation of thermal resistance in the arithmetic unit 12, the thermal resistance and temperature thresholds for the anomaly determination 21, and the concept of anomaly modes are the same as in Example 2.

[0050] The method according to this embodiment 3 makes it possible to detect abnormalities in each semiconductor module, as well as abnormalities in the TIM and cooler on a phase-by-phase basis, when multiple semiconductor modules are connected in parallel to realize multiphase AC in order to obtain high current and high voltage, and when a large number of semiconductor modules are installed. This configuration makes it easy to detect abnormalities when there are variations in the degradation of the TIM and cooler between phases due to factors such as current imbalance, or when the degradation of the cooler varies in the direction of the cooling air due to factors such as fin fouling and clogging. In addition, costs can be reduced by reducing the number of points in the cooler temperature detection unit.

[0051] (Example 4) Next, we will describe Example 4, focusing on the differences from Example 1. Figure 7 shows an example of the structure of a power converter for railway vehicles according to Example 4. Multiple semiconductor modules 51 are arranged on a heat receiving block 32. The semiconductor modules 51 are 2-in-1 modules, and two sets of parallel-connected semiconductor elements 52 (such as IGBTs or MOSFETs and diodes) are connected in series in one module. Here, the sets of parallel-connected semiconductor elements 52 are called arms 53, and each can be energized independently. In addition, the semiconductor module internal temperature detection units 54a, 54b, 54c (T1a, T1b, T1c), which are installed corresponding to each semiconductor module 51a, 51b, 51c, are arranged asymmetrically with respect to the two arms 53 in the semiconductor module 51. In the following description, the direction of the arrangement of the arms 53 in the semiconductor module 51 will be referred to as direction 61, and the direction perpendicular to the arrangement of the arms will be referred to as direction 62. Furthermore, within the semiconductor modules 51a, 51b, and 51c, the arms closer to the temperature detection unit 54 are designated 53e, 53g, and 53i, while the arms further away are designated 53f, 53h, and 53j. Figure 7(a) is a perspective view of the semiconductor module 51 and the heat receiving block 32 from the direction normal to the installation surface. Figure 7(b) is a perspective view of the semiconductor module 51, the heat receiving block 32, and the cooling fins 33 from the short side parallel to the installation surface.

[0052] First cooler temperature detection units 55a, 55b, and 55c (T2a, T2b, T2c) are arranged on the heat receiving block 32 to correspond to each row of semiconductor modules 51 in direction 62. A second cooler temperature detection unit 56 (T2d) is also arranged to correspond to each row of semiconductor modules 51 in direction 61. Here, the second cooler temperature detection unit 56 is located near the arm 53j, which is at the end of the arrangement of semiconductor modules 51 in direction 61.

[0053] As shown in Figure 7, with respect to the arm 53 (53g, 53i) closest to the semiconductor module internal temperature detection units 54b, 54c, it is assumed that the distance relationship between the semiconductor module internal temperature detection units 54b, 54c corresponding to the semiconductor module (referred to as the self-semiconductor module) 51b, 51c to which the arm belongs and the cooler temperature detection units 55b, 55c corresponding to the self-semiconductor module is equivalent to the distance relationship between the cooler temperature detection units 55a, 55b corresponding to the semiconductor modules adjacent to the self-semiconductor module (referred to as adjacent semiconductor modules) 51a, 51b. In this case, with respect to the thermal resistance 19 (R12) between the semiconductor module and the cooler, the values ​​R12bbg and R12cci obtained from the temperature history (T1b and T1c) of the semiconductor module internal temperature detection units 54b and 54c of the semiconductor modules 51b and 51c, along with the temperature history (T2b and T2c) of the cooler temperature detection units 55b and 55c installed in correspondence with the semiconductor modules 51b and 51c, are estimated to be equivalent to the values ​​R12abg and R12bci obtained from the temperature history (T2a and T2b) of the cooler temperature detection units 55a and 55b installed in correspondence with the adjacent semiconductor modules 51a and 51b. Therefore, either or both of these values ​​can be used as an abnormality indicator for the TIM of the arm 53 (53g and 53i).

[0054] Similarly, with respect to the arms 53 (53f, 53h, 53j) that are farther from the semiconductor module internal temperature detection units 54a, 54b, 54c, it is assumed that the distance relationship between the semiconductor module internal temperature detection units 54a, 54b, 54c corresponding to the semiconductor module 51a, 51b, 51c and the cooler temperature detection units 55a, 55b, 55c corresponding to the semiconductor module 51a, 51b, 51c is equivalent to the distance relationship between the semiconductor module internal temperature detection units 54b, 54c corresponding to the adjacent semiconductor module 51b, 51c, or the second cooler temperature detection unit 56. In this case, with respect to the thermal resistance 19 (R12) between the semiconductor module and the cooler, the values ​​R12aaf, R12bbh, R12ccj obtained by combining the temperature history (T2a, T2b, T2c) of the cooler temperature detection units 55a, 55b, 55c corresponding to the semiconductor modules 51a, 51b, 51c with the temperature history (T1a, T1b, T1c) of the semiconductor module internal temperature detection units 54a, 54b, 54c corresponding to the semiconductor modules 51a, 51b, 51c, and the values ​​R12abf, R12bch, R12cdj obtained by combining the temperature history (T1b, T1c, T2d) of the semiconductor module internal temperature detection unit 54b, 54c or the second cooler temperature detection unit 56 corresponding to the adjacent semiconductor module are estimated to be equivalent. Therefore, both or either of these can be used as an abnormality indicator for the TIM of arm 53 (53f, 53h, 53j).

[0055] The computing unit 12 performs the prediction of the heat generation history P and the thermal resistance 19 (R12) between the semiconductor module and the cooler for each arm 53 (53e to 53j). The prediction of the thermal resistance 19 (R12) between the semiconductor module and the cooler is performed, for example, using equations (6) to (11) shown in Table 1 below. Here, the subscripts a, b, and c represent the rows of semiconductor modules in direction 62, and the subscripts e to j represent the rows of arms in direction 62. For example, with respect to arm 53f, the thermal resistance 19(R12) between the semiconductor module and the cooler can be obtained as an indicator for determining abnormalities not only from the temperature history of the semiconductor module internal temperature detection unit 54a(T1a) and the first cooler temperature detection unit 55a(T2a) as shown in equation (7-1), but also from the temperature history of the semiconductor module internal temperature detection unit 54b(T1b) and the first cooler temperature detection unit 55a(T2a) as shown in equation (7-2). [Table 1]

[0056] Figure 8 shows an example of the processing flow of the abnormality determination unit of the system for detecting cooling abnormalities in a power converter for railway vehicles according to Embodiment 4. In the abnormality determination unit 21, threshold values ​​are set for each arm 53 for thermal resistance R12 (S402-1 to S402-6) and heat generation amount P (S403). The other abnormality determination procedures are the same as in Embodiment 1.

[0057] Of the abnormal modes, abnormal modes 2 and 3 enable abnormality detection on an arm-by-arm basis. The other abnormal modes are the same as in Example 1.

[0058] As described above, according to the method of Embodiment 4, when each arm is energized independently within the same semiconductor module, such as a 2-in-1 module, it is possible to detect abnormalities in each semiconductor module, as well as abnormalities in TIM and heat loss on an arm-by-arm basis.

[0059] In this embodiment, in order to estimate the thermal resistance of each arm, we considered using a second cooler temperature detection unit 56 to simulate the semiconductor module internal temperature detection unit. However, since the thermal resistance is estimated from the temperatures of the coolers, there is a concern that the temperature difference will be small and the estimation accuracy of the thermal resistance R12cdj will be low. For this reason, it is desirable to install the second cooler temperature detection unit 56 as close to the semiconductor module as possible. For example, a groove can be provided on the contact surface of the cooler with the semiconductor module, and the unit can be installed directly below or near the arm 53j. In addition, in this embodiment, we assumed that there is only one semiconductor module internal temperature detection unit asymmetrically arranged for the two arms 53 in the semiconductor module 51, but the semiconductor module 51c may be replaced with a module that has a semiconductor module internal temperature detection unit corresponding to each of the two arms 53. This makes it possible to obtain the same effect as in Embodiment 4 while maintaining the same thermal resistance estimation accuracy as in Embodiment 1.

[0060] The present invention is not limited to the embodiments described above, and other forms conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention, as long as they do not impair the features of the present invention. For example, the application of the power conversion device is not limited to railway vehicles, but can be applied to power conversion used in other applications such as automobiles, aircraft, and ships.

[0061] The following describes, but is not limited to, embodiments that may constitute the present invention. (Aspect 1) A system for detecting cooling abnormalities in power converters, The power conversion device includes a semiconductor module, a semiconductor module internal temperature detection unit, a cooler temperature detection unit, and a refrigerant temperature detection unit, The system includes a computing device that outputs the abnormality determination result of the power converter. The aforementioned computing device is A thermal resistance prediction unit calculates the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A system for detecting cooling abnormalities in a power converter, characterized by comprising an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation. (Aspect 2) A system for detecting cooling abnormalities in a power converter as described in Embodiment 1, A system for detecting cooling abnormalities in a power converter, characterized in that a semiconductor module internal temperature detection unit and a cooler temperature detection unit are installed corresponding to each of the multiple semiconductor modules, and the distance relationship between the semiconductor module internal temperature detection unit and the cooler temperature detection unit corresponding to the same semiconductor module includes those among the multiple semiconductor modules that have an equivalent relationship. (Aspect 3) A system for detecting a cooling abnormality in a power converter according to embodiment 1 or 2, A heat receiving block having multiple semiconductor modules on one side, The heat receiving block is provided with cooling fins on the opposite side, The semiconductor module is positioned so that its shorter side is parallel to the direction of the cooling airflow. Multiple semiconductor modules are arranged in multiple stages in directions parallel and perpendicular to the direction of the cooling airflow. The plurality of semiconductor modules arranged parallel to the direction of the cooling airflow constitute one phase of the conversion circuit. A system for detecting cooling abnormalities in a power converter, characterized in that the heat receiving block is equipped with a cooler temperature detection unit corresponding to each phase of the conversion circuit. (Aspect 4) A system for detecting a cooling abnormality in a power converter according to embodiment 1 or 2, A heat receiving block having multiple semiconductor modules on one side, The heat receiving block is provided with cooling fins on the opposite side, The longitudinal direction of the semiconductor module is oriented parallel to the direction of the cooling airflow. Multiple semiconductor modules are arranged in multiple stages in directions parallel and perpendicular to the direction of the cooling airflow. The plurality of semiconductor modules arranged in a direction perpendicular to the direction of the cooling airflow constitute one phase of the conversion circuit. A system for detecting cooling abnormalities in a power converter, characterized in that the heat receiving block is equipped with a cooler temperature detection unit corresponding to each phase of the conversion circuit. (Aspect 5) A system for detecting a cooling abnormality in a power converter according to any one of embodiments 1 to 4, A semiconductor module internal temperature detection unit and a cooler temperature detection unit corresponding to each of the multiple semiconductor modules are installed. The semiconductor module includes a plurality of arms, The calculation device outputs an abnormality detection result for each arm. With respect to the arm closest to the internal temperature detection unit of the semiconductor module (referred to as the self-semiconductor module) to which the aforementioned arm belongs, A system for detecting cooling abnormalities in a power converter, characterized in that the distance relationship between the semiconductor module temperature detection unit corresponding to the semiconductor module and the cooler temperature detection unit corresponding to the semiconductor module is the same as the distance relationship between the cooler temperature detection unit corresponding to the semiconductor module adjacent to the semiconductor module (referred to as an adjacent semiconductor module). (Aspect 6) A system for detecting a cooling abnormality in a power converter according to any one of embodiments 1 to 5, A semiconductor module internal temperature detection unit and a cooler temperature detection unit corresponding to each of the multiple semiconductor modules are installed. The semiconductor module includes a plurality of arms, The calculation device outputs an abnormality detection result for each arm. With respect to the arm furthest from the temperature detection unit within the semiconductor module (referred to as the self-semiconductor module) to which the aforementioned arm belongs, A system for detecting cooling abnormalities in a power converter, characterized in that the distance relationship between the cooler temperature detection unit corresponding to the semiconductor module itself and the semiconductor module internal temperature detection unit corresponding to the semiconductor module itself is the same as the distance relationship between the semiconductor module internal temperature detection unit corresponding to a semiconductor module adjacent to the semiconductor module itself (referred to as an adjacent semiconductor module). (Aspect 7) A system for detecting a cooling abnormality in a power converter according to any one of embodiments 1 to 6, The aforementioned computing device is characterized by determining a cooling abnormality based on data from the time when the temperature inside the semiconductor module, the cooler temperature, the refrigerant temperature, or the amount of heat generated by the semiconductor module reached its maximum value, thereby enabling detection of a cooling abnormality in a power converter. (Pattern 8) A system for detecting a cooling abnormality in a power converter according to any one of embodiments 1 to 7, The system for detecting cooling abnormalities in a power converter is characterized in that the computing device is installed on the ground or on the vehicle, and if installed on the ground, it includes a transmission device for sending and receiving data between the computing device and the power converter. (Aspect 9) A computing device that outputs the result of determining an abnormality in a power converter, A thermal resistance prediction unit calculates the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A computing device for outputting a cooling abnormality of a power converter, characterized by comprising an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation. (Aspect 10) A method for detecting a cooling abnormality in a power converter, In the thermal resistance prediction unit, the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, is calculated based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A method for detecting a cooling abnormality in a power converter, characterized in that the abnormality determination unit determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation. [Explanation of Symbols]

[0062] 1…Railway vehicles 2…Power converter 3... Dolly 4…motor 5…Transmission device 6…Vehicle information system 7…AC power 8…Temperature history inside the semiconductor module during actual operation (T1) 9…Cooler temperature history during actual operation (T2) 10…Refrigerant temperature history during actual operation (T3) 11…Abnormality determination result 12...Arithmetic device 13…Temperature detection unit (T1) inside the semiconductor module 14…Cooler temperature detection unit (T2) 15…Refrigerant temperature detection unit (T3) 16…Anomaly detection system 17…Operational history in actual service 18…Heat generation history of semiconductor modules during actual operation (P) 19…Thermal resistance (R12) between the semiconductor module and the cooler. 20…Thermal resistance between the cooler and the refrigerant (R23) 21...Abnormality determination section 31…Semiconductor Modules 32… Heat receiving block 33…Cooling fins 34...Cooling air 41, 42, 43… Semiconductor modules 44, 45, 46... Cooler temperature detection unit (T2) 51…Semiconductor module 52… Semiconductor elements 53... Arm 54…Temperature detection unit within semiconductor module (T1a, T1b, T1c) 55...First cooler temperature detection unit (T2a, T2b, T2c) 56…Second cooler temperature detection unit (T2d) 61...Arrangement direction of the arms 53 in the semiconductor module 51 62... Direction perpendicular to the arrangement direction of the arms 53 within the semiconductor module 51

Claims

1. A system for detecting cooling abnormalities in power converters, The power conversion device includes a semiconductor module, a semiconductor module internal temperature detection unit, a cooler temperature detection unit, and a refrigerant temperature detection unit, The system includes a computing device that outputs the abnormality determination result of the power converter. The aforementioned computing device is A thermal resistance prediction unit calculates the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A system for detecting cooling abnormalities in a power converter, characterized by comprising an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation.

2. A system for detecting a cooling abnormality in a power converter according to claim 1, A system for detecting cooling abnormalities in a power converter, characterized in that a semiconductor module internal temperature detection unit and a cooler temperature detection unit are installed corresponding to each of the multiple semiconductor modules, and the distance relationship between the semiconductor module internal temperature detection unit and the cooler temperature detection unit corresponding to the same semiconductor module includes those among the multiple semiconductor modules that have an equivalent relationship.

3. A system for detecting a cooling abnormality in a power converter according to claim 1, A heat receiving block having multiple semiconductor modules on one side, The heat receiving block is provided with cooling fins on the opposite side, The semiconductor module is positioned so that its shorter side is parallel to the direction of the cooling airflow. Multiple semiconductor modules are arranged in multiple stages in directions parallel and perpendicular to the direction of the cooling airflow. The plurality of semiconductor modules arranged parallel to the direction of the cooling airflow constitute one phase of the conversion circuit. A system for detecting cooling abnormalities in a power converter, characterized in that the heat receiving block is equipped with a cooler temperature detection unit corresponding to each phase of the conversion circuit.

4. A system for detecting a cooling abnormality in a power converter according to claim 1, A heat receiving block having multiple semiconductor modules on one side, The heat receiving block is provided with cooling fins on the opposite side, The longitudinal direction of the semiconductor module is oriented parallel to the direction of the cooling airflow. Multiple semiconductor modules are arranged in multiple stages in directions parallel and perpendicular to the direction of the cooling airflow. The plurality of semiconductor modules arranged in a direction perpendicular to the direction of the cooling airflow constitute one phase of the conversion circuit. A system for detecting cooling abnormalities in a power converter, characterized in that the heat receiving block is equipped with a cooler temperature detection unit corresponding to each phase of the conversion circuit.

5. A system for detecting a cooling abnormality in a power converter according to claim 1, A semiconductor module internal temperature detection unit and a cooler temperature detection unit corresponding to each of the multiple semiconductor modules are installed. The semiconductor module includes a plurality of arms, The calculation device outputs an abnormality detection result for each arm. With respect to the arm closest to the internal temperature detection unit of the semiconductor module (referred to as the self-semiconductor module) to which the aforementioned arm belongs, A system for detecting cooling abnormalities in a power converter, characterized in that the distance relationship between the semiconductor module temperature detection unit corresponding to the semiconductor module and the cooler temperature detection unit corresponding to the semiconductor module is the same as the distance relationship between the cooler temperature detection unit corresponding to the semiconductor module adjacent to the semiconductor module (referred to as an adjacent semiconductor module).

6. A system for detecting a cooling abnormality in a power converter according to claim 1, A semiconductor module internal temperature detection unit and a cooler temperature detection unit corresponding to each of the multiple semiconductor modules are installed. The semiconductor module includes a plurality of arms, The calculation device outputs an abnormality detection result for each arm. With respect to the arm furthest from the temperature detection unit within the semiconductor module corresponding to the semiconductor module to which the aforementioned arm belongs (referred to as the self-semiconductor module), A system for detecting cooling abnormalities in a power converter, characterized in that, with respect to the cooler temperature detection unit corresponding to the semiconductor module itself, the distance relationship between the semiconductor module's internal temperature detection unit corresponding to the semiconductor module itself is equivalent to the distance relationship between the semiconductor module's internal temperature detection unit corresponding to a semiconductor module adjacent to the semiconductor module itself (referred to as an adjacent semiconductor module).

7. A system for detecting a cooling abnormality in a power converter according to any one of claims 1 to 6, The aforementioned computing device is characterized by determining a cooling abnormality based on data of the time when the temperature inside the semiconductor module, the cooler temperature, the refrigerant temperature, or the amount of heat generated by the semiconductor module reached its maximum value, thereby enabling detection of a cooling abnormality in a power converter.

8. A system for detecting a cooling abnormality in a power converter according to any one of claims 1 to 6, The aforementioned computing device is installed on the ground or on the vehicle, and if installed on the ground, it is characterized by comprising a transmission device for sending and receiving data between the computing device and the power converter, wherein the system detects a cooling abnormality in a power converter.

9. A computing device that outputs the result of determining an abnormality in a power converter, A thermal resistance prediction unit calculates the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A computing device for outputting a cooling abnormality of a power converter, characterized by comprising an abnormality determination unit that determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation.

10. A method for detecting a cooling abnormality in a power converter, In the thermal resistance prediction unit, the thermal resistance between the semiconductor module and the cooler, and between the cooler and the cooler, is calculated based on the temperature history inside the semiconductor module during actual operation, the temperature history of the cooler during actual operation, the temperature history of the refrigerant during actual operation, and the heat generation history of the semiconductor module during actual operation. A method for detecting a cooling abnormality in a power converter, characterized in that the abnormality determination unit determines a cooling abnormality based on at least the thermal resistance between the semiconductor module and the cooler, the thermal resistance between the cooler and the refrigerant, the refrigerant temperature history during actual operation, and the heat generation history of the semiconductor module during actual operation.

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