Cooling device for electrical switchgear and method for operating such cooling device

Abstract

This invention relates to a cooling device for a converter system of electrical installations, particularly for electrical installations of rail vehicles, having a cooling path (39) in which at least one power loss source (14) is arranged and through which coolant can flow, and the cooling device having a temperature sensor system for detecting faults in the mass flow of the coolant, the temperature sensor system comprising at least two temperature sensors (52, 54) spaced apart from each other in the cooling path (39) in the direction of coolant delivery, wherein the two temperature sensors (52, 54) are arranged in the direction of coolant delivery before the channel (24) of the mass flow of coolant passing through the covered area of ​​the cooling path (39) having the power loss source (14). The invention also relates to a method for operating such a cooling device.

Description

Technical Field

[0001] This invention relates to a cooling device for converter systems used in electrical installations, particularly for electrical installations in rail vehicles. Furthermore, this invention relates to a method for operating such a cooling device. Background Technology

[0002] When operating electrical facilities, such as the converter systems of railway vehicles in the railway sector, significant heat loss occurs at power loss sources, such as power semiconductors. To prevent overheating of these facilities, particularly electronic components like Si-IGBTs (Insulated-Gate Bipolar Transistors) or SiC-MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), proper heat dissipation is required. This is typically achieved by circulating liquid or gaseous coolants in a cooling loop to absorb and transfer heat.

[0003] The main problem here is a malfunction in the cooling system or cooling circuit, which causes the mass flow of coolant to suddenly stop and therefore no longer dissipate heat from the power loss source. This can result in damage to the components being cooled.

[0004] For this reason, reliable monitoring of the coolant mass flow is essential to enable appropriate measures to be taken in the event of a failure to avoid indirect losses, such as the disconnection of the converter system. It must be considered that, due to the increasing power density in this type of power loss source (e.g., inverter), continuous and reliable heat dissipation becomes increasingly important.

[0005] In situations where heat or energy is dissipated powerfully and reliably, it is also essential to avoid erroneous or unintended failures in the form of hypothetical but not actually nonexistent coolant mass flow interruptions, thereby ensuring the high availability and reliability of electrical facilities, such as the converter systems contained therein. It must be considered that abrupt changes in the temperature of the coolant circulating in the cooling loop can lead to such erroneous and unintentional triggering, simply by using one or more temperature measurements as a detection principle for detecting coolant mass flow interruptions. In the railway sector, such sudden temperature changes occur, for example, when environmental conditions change abruptly, such as when a railcar enters a tunnel, causing another material flow (e.g., cooling air flowing through the heat exchanger) that cools the coolant mass flow in the heat exchanger to suddenly have a different temperature, thus resulting in the aforementioned temperature jump in the other material flow of the heat exchanger, namely the coolant mass flow.

[0006] Based on the prior art shown in Figure 1, several feasible solutions have been considered to date for identifying faults in the mass flow of the coolant. In Figure 1, a cooling device for a converter system used in electrical installations, particularly for rail vehicles, can be schematically identified, where portions of the corresponding coolant channels are visible in the cooling circuit. A heat exchanger, not visible here, is installed within the cooling circuit to cool the coolant. This heat exchanger, for example in rail vehicles, is surrounded by ambient air as a material flow, through which heat is exchanged with the mass flow of the coolant as a second material flow. In the current case, the cooling channel passes through a cooling body 12, which is connected or thermally coupled to a power loss source 14. The power loss source 14 is, for example, an IGBT module (Insulated-Gate Bipolar Transistor) of the converter system. Arrow 16 indicates that heat from the power loss source 14 enters the cooling body 12.

[0007] Faults in the mass flow of coolant through a cooling channel can now be determined in two different ways using existing technology: On the one hand, systems with a corresponding sensor 18 are known to determine the mass flow or flow rate of the coolant. However, such flow sensor 18 is typically expensive and relatively unreliable. On the other hand, it is known to arrange corresponding temperature sensors 20, 22 before or after the channel 24 of the coolant mass flow that passes through the cooling circuit or cooling channel 10 and covers the area of ​​the power loss source 14. Therefore, channel 24 should be understood as the length of the cooling channel 10 that overlaps with the power loss source 14.

[0008] Therefore, temperature sensors 20 and 22 are used to measure the corresponding temperature of the coolant before entering or exiting the channel 24.

[0009] If the power loss input, i.e., the thermal energy or heat input of the power loss source 14 to be cooled, in the coolant, the mass flow of the coolant can be determined by the temperature difference before and after the power loss source 14, as determined by the two temperature sensors 20 and 22, provided that the heat capacity of the coolant is known. If the calculated flow value is below a certain threshold, then it is caused by a disturbance.

[0010] If the power loss source 14 is designed as a power semiconductor (IGBT, MOSFET) so that the resulting losses can be continuously determined by means of a computing device, this requires accurate modeling of the switching and transmission behavior of the power loss source 14, which is configured for cooling. This requires significant effort and involves considerable uncertainty in modeling. Furthermore, for example, when a rail vehicle enters a tunnel, the coolant temperature changes abruptly due to variations in the heat exchanger environment. Determining the corresponding coolant temperatures before and after the power loss source 14 is sensitive to temperature jumps in the coolant entering the cooling body 12 or channel 24. Since the temperature difference between the two sensors 20 and 22 is included in the flow rate calculation, a temperature jump in the coolant before entering channel 24, where the coolant temperature has been detected by temperature sensor 20 located before the power loss source 14, but cannot be detected by the second temperature sensor at the end of channel 22 due to the speed of the coolant movement, can lead to erroneous and unintended triggering of coolant mass flow fault identification.

[0011] A cooling system for a vehicle is known from DE 11 2011 105 018 T5, which has a flow channel through which a liquid medium cooling the vehicle's drive unit circulates. The cooling system includes multiple temperature sensors positioned at different locations within the flow channel. A heating element cooled by the liquid medium is disposed within the flow channel. The flow rate of the liquid medium flowing through the flow channel is estimated based on the time lag required for the multiple temperature sensors to detect temperature changes caused by changes in the heating state of the heating element.

[0012] Furthermore, DE 10 2013 219 789 A1 discloses an apparatus for determining the flow rate of coolant through a cooling channel. The cooling channel is configured to cool an inverter. At least one temperature sensor is provided at at least one location in the cooling channel to determine the temperature of the coolant. The determination of the flow rate of coolant through the cooling channel is based on the temperature determined at at least one location and / or on the thermal power determined by means of a measuring unit. Summary of the Invention

[0013] Therefore, the object of the present invention is to provide a cooling device for a converter system for electrical installations, particularly for electrical installations of rail vehicles, and a method for operating such a cooling device, which on the one hand provides a simple and inexpensive fault identification solution, and on the other hand is extremely insensitive to erroneous or unintentional triggering when the mass flow of the coolant is actually not faulty.

[0014] According to the invention, this objective is achieved by a cooling device according to the invention and by a method according to the invention for operating such a cooling device. Preferred designs with advantageous improvements of the invention are the subject of the various embodiments.

[0015] The cooling device for a converter system of electrical switching facilities, particularly for electrical facilities of rail vehicles, according to the invention includes a cooling path in which at least one power loss source is integrated or arranged, and through which liquid or gaseous coolant can flow. Additionally, the cooling device includes a temperature sensor system for detecting faults in the mass flow of the coolant and, consequently, for detecting faults in the entire cooling device. This temperature sensor system includes two temperature sensors integrated at intervals from each other in the cooling path in the direction of coolant delivery. According to the invention, these two temperature sensors are arranged in the direction of coolant delivery before the channel of coolant mass flow that passes through the cooling path and covers the area of ​​the power loss source. The area covered by the power loss source and the cooling path is defined as the region in which the main heat flow is directed from the heat source to the coolant during normal operation.

[0016] In the prior art, the temperature of the coolant is measured before or after it enters the mass flow channel through the cooling path, which has a power loss source covering the area, in its delivery direction. In contrast, according to the present invention, the corresponding temperature is now measured at a larger and smaller interval before the mass flow channel of the coolant enters the cooling path, which has a power loss source covering the area, in the cooling path.

[0017] The main advantage of this measurement is that it only requires a simple assessment of the temperature difference between two temperature measurement locations at large and small distances before the mass flow of coolant enters the covered area of ​​the power loss source that traverses the cooling path. A mass flow fault always exists when the temperature difference is significantly higher than during normal operation, and when, during transient processes, the coolant temperature rise in the region near the power loss source precedes the temperature rise at the coolant temperature detection location farther from the power loss source. Both parts of these conditions can be checked in a simple manner using appropriate superposition control. Compared to existing techniques to date, this detection can be performed without complex modeling of the thermal behavior of the coolant or the entire system, or without knowledge of the power losses in the power loss sources currently introduced into the coolant.

[0018] Another significant advantage is that temperature jumps, such as those occurring in the heat exchange zone or, for example, during the existing circulation and flow of the coolant, can be reliably captured. These temperature changes in the external environment, caused by the warmer material flow of the cooling air at the heat exchanger, lead to a temperature jump in another material flow (i.e., the mass flow of the coolant), which can then be detected by means of two temperature sensors.

[0019] Because here, temperature jumps are detected first by a temperature sensor in the flow channel, away from the power loss source covering the cooling path, before they can be detected by a second sensor positioned close to the channel. This allows for differentiation from coolant mass flow malfunctions, where the corresponding time-temperature gradient is always detected first by a temperature sensor facing the coverage area. Thus, a very inexpensive and disturbance-insensitive overall system for monitoring coolant mass flow within the cooling path is obtained. Here, the cooling path is specifically part of a cooling loop in which a heat exchanger is integrated. Alternatively, an open system can be conceived, where ambient air is blown through the cooling path, for example, by means of a fan. The cooling loop is then no longer closed (only in relation to the ambient air). Therefore, a heat exchanger is not required.

[0020] According to the present invention, a temperature sensor is arranged in the region where the mass flow enters the coolant in the direction of coolant delivery, and another temperature sensor is arranged in the vicinity of the mass flow channel, which is covered by a power loss source, passing through the cooling path. When the temperature sensor arranged in the vicinity of the mass flow channel, which is covered by a power loss source, detects a corresponding undesirable temperature rise, the heat distribution generated by the input of heat energy through the power loss source in the event of a mass flow failure can be determined particularly quickly and reliably in this manner and method.

[0021] In addition, according to the present invention, a computing device is provided, which is configured to determine the temperature difference between two detected temperatures of the coolant and compare it with a threshold value, and to determine a detection sequence of temperature changes of the coolant at a measurement location and compare it with the threshold value.

[0022] In another embodiment of the invention, it is advantageous when the power loss source is coupled to a cooling body integrated in the cooling path via heat transfer, such as by direct connection or as an integral part thereof, wherein two temperature sensors are arranged on the cooling body. Thus, the cooling body ensures uniform temperature dissipation of heat energy from the power loss source and enables very fine and accurate temperature detection through the two temperature sensors.

[0023] In another advantageous embodiment of the invention, a plurality of power loss sources are provided, wherein two temperature sensors are arranged at intervals from each other in the direction of coolant delivery before a mass flow channel passing through the cooling path and covering the area of ​​the power loss sources. Viewed from the direction of coolant delivery, overheating of the plurality of power loss sources thus arranged before and after within the cooling path can be detected in a simple manner by the individual arrangement of the two temperature sensors before one of these power loss sources.

[0024] Finally, it is advantageous if the cooling path is part of a cooling loop in which a heat exchanger is integrated. Such a system is particularly reliable and easy to operate.

[0025] The advantages described above in conjunction with the cooling device according to the invention are applied in the same manner to the method of the invention for operating the cooling device.

[0026] Therefore, the method is particularly characterized by its ability to calculate the corresponding temperature difference between the coolant temperatures determined by two temperature sensors in a simple manner, and then, for example, when the temperature difference exceeds a threshold value and the gradient of the coolant temperature change in the region near the power loss source exceeds the temperature change at the measurement location of the coolant temperature far from the power loss source, a mass flow failure can be determined in a simple manner.

[0027] In this context, it is advantageous to transmit a signal about a coolant mass flow failure to an upstream facility when a limit value is exceeded, thereby shutting down the system and protecting the relevant components of the facility from overheating.

[0028] Finally, the method according to the invention has a particularly advantageous benefit: in determining the time temperature gradient (which is first detected at a temperature sensor far from the overlap region and facing the inlet), the starting point is the coolant temperature jump caused by changes in environmental conditions and, in particular, the resulting temperature fluctuations. Because the temperature gradient is thus detected in a simple manner first by a temperature sensor far from the overlap region and close to the inlet, it is possible to easily distinguish mass flow failures from such temperature jumps. This significantly contributes to system reliability, thereby enabling particularly simple and effective avoidance of unintentional and inappropriate system shutdowns. Attached Figure Description

[0029] Other advantages and details of the invention will become apparent from the following description of preferred embodiments and with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same features and functions.

[0030] The diagram shows:

[0031] Figure 1 shows a schematic diagram of a cooling device for a converter system for electrical installations in rail vehicles according to the prior art;

[0032] Figure 2 A schematic diagram of a cooling device for a converter system of electrical facilities for a rail vehicle according to a first design according to the present invention is shown.

[0033] Figure 3 It shows according to Figure 2 A schematic diagram of a cooling device, illustrating the operating mode when the mass flow of the coolant in the cooling device fails;

[0034] Figure 4 A graph showing the temperature of a temperature sensor system detected over time is presented, where a failure in the mass flow of coolant can be detected based on the temperature difference;

[0035] Figure 5 Another graph showing the temperature change over time detected by a corresponding temperature sensor is shown, in which the corresponding temperature curve can be identified, and the temperature jump of the coolant caused by changes in the environmental conditions of the rail vehicle can be determined; and

[0036] Figure 6 The diagram shows a schematic of a cooling device for a converter system of electrical facilities for rail vehicles according to another design, in which faults of multiple power loss sources can be determined via a sensor system. Detailed Implementation

[0037] Although Figure 1 illustrates a cooling device for a converter system of electrical facilities for rail vehicles according to the prior art, reference will now be made to two embodiments below. Figures 2 to 6 A cooling device for a converter system of electrical facilities for rail vehicles according to the present invention, and a method for operating such a cooling device are described.

[0038] Here, Figure 2A schematic diagram of a cooling device for a converter system used in the electrical system of a rail vehicle is shown, which includes a power loss source 30, designed, for example, as a SiC-MOSFET module (Metal oxide-Semiconductor-Field-Effect Transistor). Such a component generates a high level of heat, which must be dissipated accordingly to prevent overheating. In this embodiment, the power loss source 30 is connected to a corresponding thermally conductive coolant 32, where arrow 34 indicates the power loss input or heat transfer from the power loss source 30 to the coolant 32. Currently, the power loss source 30 and the coolant 32 are formed separately. However, it is also conceivable that the two components be constructed integrally. The power loss source 30 may also have an integrated coolant 32.

[0039] from Figure 2 As can be seen, the cooling element 32 passes through the cooling channel 36, which is itself part of the cooling path 39 of the cooling circuit 38. The heat exchanger 40 and the pump 42 are integrated into... Figure 2 In the cooling circuit 38, which is symbolically shown, liquid or gaseous cooling media or coolants circulate or flow. Instead of pump 42, other circulation devices are of course conceivable.

[0040] Heat stored in the coolant and absorbed by the loss input of the power loss source 30 is transferred to the second material flow in a known manner via heat exchanger 40. In the case of a rail vehicle, this second material flow is formed, for example, by ambient air that is accelerated, for example by a fan, and then flows through heat exchanger 40 or cooler, thereby cooling the material flow or mass flow of coolant circulating in cooling circuit 38.

[0041] The coolant cooled in the heat exchanger 40 enters the cooling channel 36 located within the cooling body 32 in the region of the mass flow inlet 44 within the cooling path 39. Further along the mass flow, or further along the transport direction indicated by the arrow in the cooling circuit 38 or cooling path 39, the coolant then enters the longitudinal range of the mass flow, within the cooling channel 36, in the covered area of ​​the cooling circuit 38 having the power loss source 30, or in the channel 48. The covered area of ​​the power loss source 30 and the cooling circuit 38 or cooling channel is defined as the area in which the main heat flow is directed from the heat source to the coolant during normal operation. Therefore, the channel 48 should be understood as the portion of the cooling channel 36 in which the mass flow of the coolant is substantially covered by the power loss source 30. Accordingly, in the region of this channel 48, the power loss input from the power loss source 30 is also realized via the cooling body 32 into the coolant (arrow 34). In the present case, for example, water is used as the coolant. After the coolant has passed through the cooling body 32, the coolant leaves the outlet 50 again from the outlet or cooling passage 36 and from there reaches the pump 42 again. Through the pump, the coolant reaches the heat exchanger 40 again in a further path, where the coolant releases the heat absorbed from the power loss source 30 to the surrounding air flowing through the heat exchanger 40.

[0042] from Figure 2 It can also be seen that the temperature sensor system is part of the cooling device, which in the present case includes a first temperature sensor 52 and a second temperature sensor 54. The first temperature sensor 52 is arranged here relative to the coolant delivery direction 46 in the region of the mass flow inlet 44 within the coolant body 32. The second temperature sensor 54 is arranged in the vicinity of or immediately in front of the mass flow channel 48, which passes through the cooling circuit 38 or cooling path 39 and has a coverage area of ​​the power loss source 30. Therefore, with respect to the coolant delivery direction 46, the temperature sensors 52 and 54 are located in front of the mass flow channel 48, which passes through the cooling circuit 38 and has a coverage area of ​​the power loss source 30. The two temperature sensors 52 and 54 can also be arranged outside the cooling body 32, if possible, directly in the corresponding lines of the cooling circuit 38. However, the current arrangement of the temperature sensors 52 and 54 within the cooling body 32 is particularly advantageous because of the good thermal coupling between the sensors and the coolant.

[0043] Here, a method for operating the cooling device is proposed, wherein, during coolant circulation, two temperature sensors 52 and 54 determine the corresponding temperature at inlet 44 or upstream of channel 48. As now from... Figure 4As can be seen on the graph near its vertical axis, the corresponding temperature measurement curves A and B are generally constant over time and parallel to each other. Temperature measurement curve A, which measures the temperature at inlet 44 using temperature sensor 52, is generally smaller than temperature measurement curve B, which measures the temperature in the region preceding channel 48 using temperature sensor 54. This is related to the fact that at the measurement location of the second temperature sensor 54, the coolant flowing in the region of the cooling body 32, or in the region, has a slightly elevated temperature due to the power loss input caused by the power loss source 30. Therefore, temperature A corresponds to the coolant inlet temperature. On the other hand, temperature B, measured by temperature sensor 54, is only slightly higher than temperature A because a portion of the power introduced by the power loss source 30 diffuses against the flow direction of the coolant, thus the temperature represented by temperature measurement curve B is slightly higher. Therefore, the temperature difference can be determined by subtracting the value of temperature measurement curve A from the value of temperature measurement curve B. Thus, a small positive temperature difference ΔT can be determined during normal operation of the cooling device.

[0044] If, at some point in time (line 53), pump 42 malfunctions or the coolant mass flow within cooling circuit 38 stops, the temperature of channel 48 directly below power loss source 30 or in the area covered by power loss source 30 passing through cooling channel 36 will rise due to power loss from power loss source 30 continuing to enter cooling body 32 or due to the power loss of the coolant. The resulting temperature difference, or the diffusion of heat energy introduced into the coolant, will cause a heat flow opposite to the normal flow direction of the coolant mass flow, such as in… Figure 3 The middle part is shown with the help of the corresponding line 55.

[0045] Because this heat flow is opposite to the normal flow direction, the temperature determined by temperature sensor 54 rises very rapidly and sharply, as in Figure 4 Based on temperature curve B, due to the distance from the power loss source 30, the temperature measured by temperature sensor 52 at the inlet 44 entering the coolant 32 increases slightly after a significant delay. This delay is due to the heat flow diffusing in the opposite direction to the normal flow direction. This heat flow requires some time after reaching the measurement location in the area of ​​temperature sensor 52, and only then can temperature sensor 52 measure the corresponding temperature increase in the inlet 44 area of ​​the coolant 32. The trend of temperature curve A in the inlet 44 area can also be seen... Figure 4 I saw it in the middle.

[0046] from Figure 4 It can be clearly seen that, using the dashed line 53, after the point in time when the coolant circulation or mass flow fails in the cooling loop 38, the temperature measurement curve B rises significantly, and the temperature measurement curve A subsequently rises more gently. The temperature difference ΔT thus increases, which is based on... Figure 4This can be clearly seen in the chart.

[0047] The temperature difference ΔT can be continuously checked here through the evaluation unit. The temperature difference ΔT can be compared with the threshold value defining a mass flow fault in the calculation unit. When the threshold value is exceeded, a signal regarding the coolant mass flow failure can be transmitted to the facility. Therefore, a coolant mass flow fault always exists when the temperature difference ΔT between temperature sensor 54 and temperature sensor 52 is significantly higher than during normal operation, and when the temperature rise in the area of ​​temperature sensor 54 exceeds the temperature rise in the area of ​​temperature sensor 52. Both parts of this condition can be checked using a suitable superposition (UEBERLATER) controller.

[0048] Figure 5 Another temperature graph showing two temperature measurement curves A and B versus time t is presented. Here, two temperature jumps 56 and 58 at corresponding time points are plotted in the graph. These temperature jumps 56 and 58 occur, for example, when conditions in heat exchanger 40 change significantly, such as when a rail vehicle enters a tunnel with a significantly different temperature than before. Therefore, if this activates coolant circulation and mass flow, and causes a temperature jump in the material flow of the heat exchanger, i.e., the cooling air, this correspondingly leads to a temperature jump in the coolant. This jump occurs at the coolant inlet; more precisely, due to the direction of coolant flow, the jump always occurs first at temperature sensor 52 near inlet 44, and subsequently at temperature sensor 54 before the coolant enters channel 48 over time. Thus, the order in which temperature changes are detected is completely reversed compared to the order in case of mass flow failure (as described previously). Therefore, at the first temperature jump at point 56 online, a negative temperature difference ΔT is determined between temperature measurement curves B and A, which is distinguished from the temperature difference ΔT detected in the case of a mass flow failure due to the change in sign. Thus, coolant jumps in the input can be differentiated from coolant mass flow failures.

[0049] For example, after leaving the tunnel, the second temperature jump of the coolant will not be observed in the region of line 58 until the trends of temperature measurement curves A and B are normalized again over time.

[0050] at last, Figure 6Another embodiment of the cooling device is illustrated schematically, showing the cooling channel 36 of the cooling circuit 38 in a highly schematic manner. A cooling body 32 in the form of a cooling plate is arranged on this cooling channel 36, and two power loss sources 30, for example, in the form of power semiconductors, are arranged on this cooling body. Corresponding temperature sensors 52 and 54 can be seen here, arranged at correspondingly larger or smaller distances from the respective power loss sources 30. It can be particularly seen that even when using two power loss sources 30, only one temperature sensor system with a pair of temperature sensors 52 and 54 is required, through which faults in the preceding and following power loss sources 30 observed along the coolant delivery direction 46 are detected. In other words, even when using two power loss sources 30, only one pair of temperature sensors 52 and 54 is needed.

Claims

1. A cooling device for electrical installations, the cooling device having a cooling path (39) in which at least one power loss source is arranged, and through which a coolant can flow, and the cooling device having a temperature sensor system for detecting faults in the mass flow of the coolant, the temperature sensor system comprising at least two temperature sensors integrated at intervals from each other in the cooling path (39) in the coolant delivery direction (46). in, Two temperature sensors are arranged in the coolant delivery direction (46) before the mass flow channel of the coolant passing through the cooling path (39) and covering the area of ​​the power loss source. One temperature sensor is arranged in the region of the inlet (44) of the mass flow entering the cooling body in the coolant delivery direction (46), and the other temperature sensor is arranged in the vicinity of the mass flow channel passing through the cooling circuit (38) and covering the area of ​​the power loss source. A computing device is provided, configured to determine the temperature difference (ΔT) between the two detected temperatures of the coolant and compare the temperature difference with a threshold value. The computing device is also configured to determine... The detection sequence of temperature change of the coolant at the measurement location is compared with a threshold value. When the temperature difference (ΔT) between another temperature sensor in the vicinity before the channel and the temperature sensor in the region of the inlet (44) of the mass flow into the coolant in the delivery direction (46) of the coolant is significantly greater than the temperature difference during normal operation, and when the temperature rise in the region of the other temperature sensor in the vicinity before the channel precedes the temperature rise in the region of the temperature sensor in the region of the inlet (44) of the mass flow into the coolant in the delivery direction (46) of the coolant, a coolant mass flow failure exists.

2. The cooling device according to claim 1, characterized in that, The cooling device is used in the converter system of the electrical facilities of rail vehicles.

3. The cooling device according to claim 1 or 2, characterized in that, The power loss source is coupled to the cooling body integrated in the cooling path (39) in a heat transfer manner, and two temperature sensors are arranged at the cooling body.

4. The cooling device according to claim 3, characterized in that, Multiple power loss sources are provided, wherein two of the temperature sensors are arranged at intervals from each other in the direction of coolant delivery before a mass flow channel having a coverage area of ​​the power loss sources that passes through the cooling path (39).

5. The cooling device according to claim 1 or 2, characterized in that, The cooling path (39) is part of the cooling circuit (38), in which a heat exchanger (40) is integrated.

6. A method of operating a cooling device for electrical installations, wherein, Coolant flows through a cooling path (39), in which at least one power loss source is arranged, and wherein a fault in the mass flow of coolant is detected by a temperature sensor system comprising at least two temperature sensors spaced apart from each other in the cooling path (39) in the coolant delivery direction (46), wherein the two temperature sensors are arranged in the coolant delivery direction (46) before the channel of the coolant mass flow passing through the cooling path (39) with the coverage area of ​​the power loss source, and the corresponding temperature of the coolant is detected by means of the two temperature sensors and the fault in the mass flow is monitored based on the determined temperature of the coolant, wherein, on the one hand, the temperature of the coolant in the region where the mass flow enters the cooling body in the coolant delivery direction (46) is detected, and on the other hand, the temperature in the coverage area with the power loss source passing through the cooling path (39) is detected. The temperature in the area near the channel of the coolant in the covered area, and the temperature difference (ΔT) between the two detected temperatures of the coolant determined by means of a computing device and the temperature difference compared with a threshold value, and the detection sequence of the temperature change of the coolant at the measurement location determined by means of the computing device and the detection sequence compared with a threshold value, when the temperature difference (ΔT) between another temperature sensor in the area near the channel and the temperature sensor in the area of ​​the inlet (44) of the coolant in the delivery direction (46) of the coolant is significantly greater than the temperature difference during normal operation, and when the temperature rise in the area of ​​the other temperature sensor in the area near the channel precedes the temperature rise in the area of ​​the temperature sensor in the area of ​​the inlet (44) of the coolant in the delivery direction (46) of the coolant, there is a failure of the coolant mass flow.

7. The method according to claim 6, characterized in that, The cooling device is used in the converter system of the electrical facilities of rail vehicles.

8. The method according to claim 6 or 7, characterized in that, The corresponding temperature of the coolant is determined by means of two temperature sensors integrated in the cooling body (39) in the cooling path, which is coupled to the power loss source in a heat transfer manner.

9. The method according to claim 6 or 7, characterized in that, When the threshold value is exceeded, a signal indicating a fault in the mass flow of the coolant is transmitted to the electrical facility.

10. The method according to claim 6 or 7, characterized in that, The temperature jumps of the coolant are distinguished from the failures of the coolant's mass flow by evaluating the detection sequence of the temperature difference and temperature change of the coolant at the two sensors.

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