JP4340890B2 - Fever detection device - Google Patents

Description

  The present invention relates to a heat generation detection device capable of detecting a heat generation state of a heat generation element such as a semiconductor chip.

For example, Patent Document 1 introduces a heat generation detection device having a semiconductor chip and a thermal diode. The semiconductor chip generates heat due to Joule heat during energization. Here, the diffusion thermal resistance is smaller in the peripheral portion of the semiconductor chip than in the central portion of the semiconductor chip. For this reason, the temperature distribution of the semiconductor chip becomes a contour line with the central portion of the semiconductor chip as the highest temperature portion. In order to protect the semiconductor chip from damage due to overheating, it is necessary to detect the heat generation state of the highest temperature portion. In view of this point, the thermal diode is arranged at the center of the semiconductor chip.
JP-A-10-116987

  However, according to the heat generation detection device described in the same document, if the fluid for cooling the semiconductor chip has a temperature gradient, it is difficult to detect the heat generation state of the highest temperature portion of the semiconductor chip. FIG. 7 shows a schematic diagram when a semiconductor chip of a conventional heat generation detecting device is cooled by a fluid. As shown in FIG. 7A, the heat generation detection device 100 includes a semiconductor chip 101 and a thermal diode 102. The thermal diode 102 is disposed at the center of the semiconductor chip 101. The fluid flows from the upstream side toward the downstream side as indicated by arrows in the figure, and cools the semiconductor chip 101. As shown in FIG. 7B, the heat generation (heat generation amount per unit time) of the semiconductor chip 101 is substantially uniform over the entire surface of the semiconductor chip 101. As shown in FIG. 7C, the diffusion thermal resistance is smaller in the peripheral portion of the semiconductor chip than in the central portion of the semiconductor chip.

  Here, as shown in FIG. 7D, the temperature of the fluid is not uniform in the fluid flow direction. The temperature of the fluid gradually increases from the upstream side toward the downstream side. For this reason, the cooling efficiency gradually decreases from the upstream side toward the downstream side. Therefore, as shown in FIG. 7 (e), the maximum temperature portion T ′ in the temperature distribution of the semiconductor chip 101 is downstream by a distance L ′ from the center M ′ of the semiconductor chip 101 in the fluid flow direction. It will shift. For this reason, the position of the thermal diode 102 and the maximum temperature portion T ′ are shifted. Therefore, it becomes difficult for the thermal diode 102 to detect the heat generation state of the highest temperature portion of the semiconductor chip 101.

  The heat generation detection device of the present invention has been completed in view of the above problems. Therefore, an object of the present invention is to provide a heat generation detection device that can detect a heat generation state of a high temperature portion of a heat generating element even when the fluid has a temperature gradient.

(1) In order to solve the above-described problem, the heat generation detection device of the present invention includes a heat generation element that generates heat when energized and is cooled by a liquid fluid, and at least one that detects a heat generation state of the heat generation element disposed in the heat generation element. A heat generation detecting device comprising two temperature sensing elements, wherein the heat generation device is arranged such that a center of at least one of the temperature sensing elements is downstream of a center of the heat generation element in the fluid flow direction. The at least one temperature sensitive element arranged in the element is arranged in a maximum temperature portion in a temperature distribution of the heating element .

  As described above, the maximum temperature portion of the heating element is shifted downstream from the center of the heating element (see FIG. 7E). Therefore, in the fluid flow direction, the center of at least one of the temperature sensing elements of the heat generation detecting device of the present invention is disposed downstream of the center of the heating element.

According to the exothermic detection device of the present invention, since the center of the temperature sensing element is arranged on the heating element so as to be downstream from the center of the heating element, the maximum temperature portion can be accurately detected, and the temperature sensing element and the maximum temperature are detected. The positional deviation from the part can be reduced. For this reason, in the fluid flow direction, it is possible to detect a heat generation state in a portion higher than the center of the heat generating element (not limited to the highest temperature portion).

Further, at least one of the temperature sensitive device shall be the structure that is arranged in a maximum temperature portion in the temperature distribution of the heating elements. In this configuration, at least one temperature sensitive element and the maximum temperature portion of the heating element and the positional deviation are made zero. According to this configuration, the heat generation state of the highest temperature portion can be detected by the temperature sensitive element.

( 2 ) Preferably, the heating element is a semiconductor chip. According to this configuration, the semiconductor chip can be protected from a failure due to overheating.

( 3 ) Preferably, the fluid flows through a cooling passage partitioned inside a cooling pipe, and the heating element is cooled by the fluid via a wall of the cooling pipe. . According to this configuration, the heating element and the fluid are separated from each other by the wall of the cooling pipe. For this reason, compared with the case where a fluid contacts a heat generating element, a turbulent flow etc. are hard to generate | occur | produce in a fluid. That is, it is easy to grasp and control the flow of fluid. For this reason, the position setting of a temperature sensing element becomes comparatively easy.

( 4 ) Preferably, the temperature sensitive element is a thermal diode. The forward voltage of the thermal diode varies with temperature. Specifically, when the same forward current flows, the higher the temperature, the smaller the forward voltage. From this forward voltage, the heat generation state of the heat generating element can be detected. According to this configuration, the heat generation state of the heat generating element can be detected relatively easily.

  According to the present invention, it is possible to provide a heat generation detection device capable of detecting the heat generation state of the high temperature portion of the heat generating element even when the fluid has a temperature gradient.

  Hereinafter, an embodiment in which the heat generation detection device of the present invention is embodied as a switching module of a power stack will be described.

  First, the configuration of a power stack having the switching module of this embodiment will be described. FIG. 1 is an exploded perspective view of a power stack having the switching module of the present embodiment. FIG. 2 shows a combined perspective view of the power stack. FIG. 3 is an exploded perspective view of the switching module of the present embodiment. FIG. 4 shows a cross-sectional view of the power stack.

  As shown in these drawings, the power stack 1 includes a cooling tube 2, an introduction tube 4, a lead-out tube 5, and a switching module 6. The cooling tube 2 is included in the cooling tube of the present invention. The switching module 6 is included in the heat generation detection device of the present invention.

  The cooling tube 2 is made of aluminum and has a flat rectangular tube shape with rounded end portions in the length direction. At both ends in the length direction of the cooling tube 2, an inlet 20 and an outlet 21 are opened. The inlet 20 and the outlet 21 communicate with each other through a cooling passage 22 formed inside the cooling tube 2. In the cooling passage 22, cooling fins (not shown) are arranged along the length direction of the cooling passage 22. A total of ten cooling tubes 2 are arranged substantially parallel to each other. Two switching modules 6 are interposed between adjacent cooling tubes 2 along the length direction of the cooling tubes 2.

  The switching module 6 includes an IGBT (Insulated Gate Bipolar Transistor) 6a (indicated by a dotted line in FIG. 3), a flywheel diode 6b (indicated by a dotted line in FIG. 3), an electrode terminal 6c, a signal terminal 6d, an insulating plate 6e, and a resin mold 6f. And. The IGBT 6a is included in the semiconductor chip of the present invention. A thermal diode (not shown) is disposed in the IGBT 6a. The thermal diode will be described in detail later. The switching module 6 is used for driving an MG (Motor Generator) (not shown). The resin mold 6f is made of an insulating resin and has a flat rectangular plate shape. The IGBT 6a and the flywheel diode 6b are sealed inside the resin mold 6f. The electrode terminal 6c is made of copper and has a strip shape. The electrode terminal 6c is projected from the upper surface of the resin mold 6f. A total of two electrode terminals 6c are arranged. The signal terminal 6d is made of copper and has a pin shape. The signal terminal 6d protrudes from the lower surface of the resin mold 6f. A total of five signal terminals 6d are arranged. The signal terminal 6d is connected to a control board (not shown). The insulating plate 6e is made of ceramic and has a rectangular plate shape. A total of two insulating plates 6e are arranged on both opposing surfaces of the resin mold 6f.

  The introduction pipe 4 includes an introduction main pipe 40 and an introduction communication pipe 41. The introduction communication pipe 41 is made of aluminum and has a short-axis cylindrical shape having a bellows (not shown). The introduction communication pipe 41 connects the introduction ports 20 of the cooling tubes 2 adjacent to each other. A total of nine introduction communication pipes 41 are arranged in a substantially straight line.

  The introduction main pipe 40 is made of aluminum and has a cylindrical shape with a longer axis than the introduction communication pipe 41. One end of the introduction main pipe 40 covers the introduction port 20 of the cooling tube 2 on the most upstream side. Water dilution LLC (Long Life Coolant) is introduced from the heat radiating device 10 to the cooling tube 2 through the introduction main pipe 40. Water dilution LLC is included in the fluid of the present invention.

  The lead-out pipe 5 includes a lead-out main pipe 50 and a lead-out communication pipe 51. The lead-out communication pipe 51 is made of aluminum and has a short-axis cylindrical shape having a bellows (not shown). The outlet communication pipe 51 connects the outlet ports 21 of the cooling tubes 2 adjacent to each other. A total of nine lead-out communication pipes 51 are arranged in a substantially straight line.

  The lead-out main pipe 50 is made of aluminum and has a cylindrical shape. The lead-out main pipe 50 is arranged substantially parallel to the introduction main pipe 40. One end of the outlet main pipe 50 covers the outlet 21 of the cooling tube 2 on the most downstream side. The water dilution LLC after heat exchange is led out from the cooling tube 2 to the heat radiating device 10 via the lead-out main pipe 50.

  Next, the flow of the water dilution LLC in the power stack having the switching module of the present embodiment will be described. As shown in FIG. 4, the water dilution LLC is supplied from the heat radiating device 10 to the introduction main 40. The water dilution LLC is introduced into the cooling passage 22 of each of the ten cooling tubes 2 from the introduction main pipe 40 directly or via the introduction communication pipe 41. By the way, the switching module 6 generates heat by driving the MG. The heat of the switching module 6 is transmitted to the water dilution LLC flowing through the cooling passage 22 through the wall of the cooling tube 2. The water dilution LLC heated by the heat of the switching module 6 flows into the lead-out main pipe 50 from the cooling passage 22 directly or via the lead-out communication pipe 51. The water dilution LLC merged in the lead-out main pipe 50 is led out to the heat radiating device 10. The water diluted LLC recooled by the heat radiating device 10 is again introduced into the introduction main 40. That is, the water dilution LLC circulates between the heat dissipation device 10 and the power stack 1 through the path of the heat dissipation device 10 → the introduction pipe 4 → the cooling tube 2 (cooling passage 22) → the outlet pipe 5 → the heat dissipation device 10 again. Yes. And the water dilution LLC is keeping the temperature of the switching module 6 so that it may become below allowable temperature.

  Next, the thermal diode of the switching module of this embodiment will be described. FIG. 5 shows a transmission schematic diagram of the cooling tube and the switching module as seen from the direction V in FIG. For convenience of explanation, the switching module is indicated by a one-dot chain line. In addition, the flywheel diode is omitted.

  As shown in the figure, the water dilution LLC cools the IGBT 6 a while flowing in the cooling passage 22. FIG. 6 shows the relationship between the IGBT of FIG. 5 and the flow of water dilution LLC. As shown in FIG. 6B, the heat generation (heat generation amount per unit time) of the IGBT 6a is substantially uniform over the entire surface of the IGBT 6a. As shown in FIG. 6C, the diffusion thermal resistance is smaller in the peripheral portion of the IGBT 6a than in the central portion of the IGBT 6a. As shown in FIG. 6D, the temperature of the water dilution LLC is not uniform in the flow direction of the water dilution LLC. The temperature of the water dilution LLC gradually increases from the upstream side to the downstream side by heat exchange with the IGBT 6a. For this reason, the cooling efficiency gradually decreases from the upstream side toward the downstream side. Therefore, as shown in FIG. 6 (e), the maximum temperature portion T in the temperature distribution of the IGBT 6a is shifted downstream by a distance L2 from the center M of the IGBT 6a in the flow direction of the water dilution LLC. However, as shown in FIG. 6 (a), the center of the thermal diode 60a is also shifted from the center M of the IGBT 6a in the water dilution LLC flow direction by a distance L1 downstream. Further, the distance L1 is set to be the distance L2.

  The thermal diode 60a is a polycrystalline silicon diode. The forward voltage of the thermal diode 60a has a negative temperature coefficient. That is, when the temperature of the IGBT 6a increases, the forward voltage of the thermal diode 60a decreases. From this voltage, the temperature of the maximum temperature portion T is detected. When the IGBT 6a is in an overheated state, the IGBT 6a is forcibly turned off. In this way, the power stack 1 protects the IGBT 6a from malfunction due to overheating.

  Next, the effect of the switching module of this embodiment is demonstrated. According to the switching module 6 of the present embodiment, the thermal diode 60a is shifted downstream from the center M of the IGBT 6a. Further, the amount of deviation L1 of the center of the thermal diode 60a with respect to the center M of the IGBT 6a coincides with the amount of deviation L2 of the maximum temperature portion T with respect to the center M of the IGBT 6a. In other words, the center of the thermal diode 60a is arranged at the highest temperature portion T of the IGBT 6a. For this reason, the heat generation state of the maximum temperature portion T can be reliably detected by the thermal diode 60a. Therefore, it is possible to suppress the occurrence of problems due to overheating in the IGBT 6a.

  Further, according to the switching module 6 of the present embodiment, the IGBT 6 a and the water dilution LLC are isolated by the tube wall of the cooling tube 2. For this reason, compared with the case where fluids, such as airflow, contact IGBT6a, for example, it is hard to generate turbulent flow etc. in fluid. That is, it is easy to control and grasp the flow of the water dilution LLC. For this reason, the position setting of the thermal diode 60a (that is, the setting of the distance L1) is relatively easy.

  The embodiment of the heat generation detection device of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, the type of the semiconductor chip is not particularly limited to the IGBT 6a. A power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a GTO (Gate Turn-off Thyristor), or the like may be used. The type of the temperature sensitive element is not particularly limited to the thermal diode 60a. For example, a thermistor may be used.

  Further, the number of the temperature sensitive elements arranged is not particularly limited. When arranging a plurality of temperature sensing elements, it is only necessary that the center of at least one temperature sensing element be shifted downstream from the center M of the IGBT 6a in the water dilution LLC flow direction. In other words, another temperature sensing element may be arranged upstream of the center M.

  Moreover, the heating element off control method is not particularly limited. For example, an analog circuit including the IGBT 6a and the thermal diode 60a may be assembled, and the IGBT 6a may be controlled to be turned off by hardware according to a forward voltage change of the thermal diode 60a. Further, the voltage value of the thermal diode 60a is digitally converted, the converted digital value is compared with a predetermined threshold value in the microcomputer, and if the digital value> the threshold value, the IGBT 6a is controlled to be off by the control signal from the microcomputer. May be.

  Moreover, in the said embodiment, although the heat_generation | fever detection apparatus of this invention was embodied as the switching module 6, the heat_generation | fever detection apparatus of this invention can be embodied as various apparatuses which require the temperature detection of a heat generating element.

  Hereinafter, the simulation of the position setting of the thermal diode 60a (that is, the setting of the distance L1) performed for the switching module 6 will be described. In the simulation, the output of the IGBT 6a was 500W. The flow rate of water diluted LLC was 1 l / min. It was. The temperature gradient of the water dilution LLC was 600 K / m from the upstream side to the downstream side of the cooling passage 22.

As a result of simulation, it was found that the maximum temperature portion T in the temperature distribution of the IGBT 6a is shifted by 1.5 × 10 ⁻³ m downstream from the center M of the IGBT 6a in the flow direction of the water dilution LLC. Therefore, it was found that when the switching module 6 is used under the above simulation conditions, the center of the thermal diode 60a may be shifted from the center M of the IGBT 6a by 1.5 × 10 ⁻³ m downstream.

1 is an exploded perspective view of a power stack having a switching module according to an embodiment of the present invention. It is a united perspective view of the power stack. It is a disassembled perspective view of the switching module of this embodiment. It is sectional drawing of the same power stack. It is the permeation | transmission schematic diagram of the cooling tube and switching module seen from the V direction of FIG. (A) is a schematic diagram which shows the relationship between IGBT of FIG. 5, and the flow of water dilution LLC. (B) is a schematic diagram showing heat generation of the IGBT. (C) is a schematic diagram which shows the diffusion thermal resistance of IGBT. (D) is a schematic diagram showing water dilution LLC temperature. (E) is a schematic diagram which shows the temperature distribution of IGBT. (A) is a schematic diagram which shows the relationship between the conventional semiconductor chip and the flow of a fluid. (B) is a schematic diagram which shows the heat_generation | fever of a semiconductor chip. (C) is a schematic diagram which shows the diffusion thermal resistance of a semiconductor chip. (D) is a schematic diagram showing fluid temperature. (E) is a schematic diagram which shows the temperature distribution of a semiconductor chip.

Explanation of symbols

  1: Power stack, 2: Cooling tube (cooling tube), 20: Inlet port, 21: Outlet port, 22: Cooling passage, 4: Introducing tube, 40: Introducing main tube, 41: Introducing communication tube, 5: Outlet tube 50: Derived main pipe, 51: Derived communication pipe, 6: Switching module (heat generation detector), 6a: IGBT (semiconductor chip), 6b: Flywheel diode, 6c: Electrode terminal, 6d: Signal terminal, 6e: Insulation Plate, 6f: resin mold, 60a: thermal diode, 10: heat dissipation device, L1: amount of deviation of the center of the thermal diode with respect to the center of the IGBT, L2: amount of deviation of the highest temperature portion with respect to the center of the IGBT, M: center, T: Maximum temperature part.

Claims (4)

A heating detection device comprising: a heating element that generates heat when energized and is cooled by a liquid fluid; and at least one temperature-sensitive element that is disposed in the heating element and detects a heating state of the heating element,
In the fluid flow direction, the center of the at least one temperature sensing element is disposed on the heating element so as to be downstream from the center of the heating element, and the at least one temperature sensing element is the heating element. The heat generation detecting device is arranged at the highest temperature portion in the temperature distribution of   The heat generation detection device according to claim 1, wherein the heat generating element is a semiconductor chip. The fluid flows through a cooling passage defined inside the cooling pipe,
The heat generation detecting device according to claim 1, wherein the heat generating element is cooled by the fluid through a wall of the cooling pipe.   The heat generation detecting device according to claim 1, wherein the temperature sensitive element is a thermal diode.

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