JP2008005698A - Semiconductor power converter for electric railroad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor power converter for electric railroad for cooling semiconductor devices, even if the outside air temperature is lower than the freezing point of a cooling liquid inside a heat pipe. <P>SOLUTION: The electric railroad semiconductor power converter includes a variable conductance heat pipe that uses pure water as the cooling liquid for cooling the semiconductor device. When the semiconductor device contacts a heat-receiving block, heat is generated in the semiconductor device, transmitted to the variable conductance heat pipe via the heat receiving block and escapes from a heat dissipation fin in the variable conductance heat pipe to the ambient air. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor power conversion device for substation equipment installed on the ground to supply or regenerate electric power to an electric railway.

  In order to supply or regenerate electric power to an electric railway, a power conversion circuit as shown in FIG. 5 or 6 is used. In the power conversion circuit shown in FIG. 5, AC power is converted into DC power by a rectifier circuit using a diode 11, and power is supplied to the electric railway vehicle 14 via the feeder line 13 of the electric railway. In the power conversion circuit shown in FIG. 6, regenerative power accompanying deceleration of the electric railway vehicle 14 is absorbed from the feeder line 13 of the electric railway, and power is supplied to the AC circuit using a controllable semiconductor device such as the thyristor 12. Regenerate. In these power conversion circuits, when power conversion is performed, heat loss occurs in the power semiconductor device (hereinafter abbreviated as “semiconductor device”). Therefore, it is necessary to cool the semiconductor device so that the semiconductor device is not damaged by heat.

  Cooling a semiconductor device by a boiling cooling method has been widely used as a prior art. FIG. 7 shows a boiling cooling type semiconductor power conversion device for railways. In FIG. 7, reference numeral 1 denotes a semiconductor device, 9 denotes a heat-receiving block that plays a role of supplying electricity to the semiconductor device 1, and transfers heat to the coolant 21, 5 denotes an electric connection between the semiconductor device 1 and the heat-receiving block 9 This is an insulating plate that is electrically insulated.

  In an actual power converter, a plurality of semiconductor devices 1 are used, but only one semiconductor device 1 is shown in FIG. As shown in FIG. 7, all of these are in a tank 22 filled with a coolant 21. When the heat loss of the semiconductor device 1 exceeds a certain level, the cooling liquid 21 boils and vaporizes at the location of the heat receiving block 9, and the vapor of the vaporized cooling liquid 21 passes through the sleeve 23 disposed in the upper part of the tank 22 and is condensed. The heat is dissipated and liquefied at 24, returned to the tank 22, and again receives heat from the heat receiving block 9 and vaporizes. Patent Document 1 and Patent Document 2 describe a boiling cooling type similar to FIG.

  As another prior art, there is a semiconductor power conversion device of heat pipe cooling. FIG. 9 shows the principle of the heat pipe. Reference numeral 2 in FIG. 9 is a heat receiving block that transfers heat generated by the semiconductor device to the heat pipe 35. The coolant 32 contained in the heat pipe 35 boils or vaporizes due to the heat of the heat receiving block 2 and transports the heat to the upper part of the heat pipe 35. The heat radiation fin 4 is attached to the upper part of the heat pipe 35, and the vaporized coolant 32 gives heat to the heat radiation fin 4 to be liquefied. Patent Document 3 describes a semiconductor cooling device using a heat pipe.

JP 58-37482 A Japanese Patent Laid-Open No. 5-21258 Japanese Unexamined Patent Publication No. 7-190655

  In the boiling cooling of the prior art, when the ambient temperature is lowered to a temperature at which the cooling liquid 21 is frozen, the cooling liquid 21 that has come to the condensing unit 24 is frozen and does not return to the tank 22, thereby cooling the semiconductor device 1. Can not be. In order to avoid this, a chlorofluorocarbon liquid having a low freezing point is generally used as the cooling liquid 21. However, since the chlorofluorocarbon liquid is a substance having a high global warming potential as a greenhouse gas, it should be avoided if possible. When water having no greenhouse effect is used as the cooling liquid, it is necessary to provide a heater to prevent freezing when the ambient temperature is below freezing, and power consumption by the heater is inevitable below freezing.

  In the other prior art, water is used for the cooling liquid 32 inside the heat pipe 35. However, when the radiating fins 4 are exposed to a low temperature below the freezing point of the cooling liquid 32 as in the boiling cooling method, the cooling liquid 32 is used. However, since the cooling liquid 32 that has been frozen at the upper part of the heat pipe 35 and turned into a solid does not return to the lower part of the heat pipe 35, the cooling liquid 32 at the lower part of the heat pipe 35 gradually decreases, and the semiconductor device continuously There is a problem that 1 cannot be cooled.

  An object of the present invention is to provide a semiconductor power converter for electric railway that can cool a semiconductor device even if the ambient temperature is a low temperature that solidifies the coolant, and in particular, the ambient temperature is a heat pipe. An object of the present invention is to provide a semiconductor power converter for electric railway that can cool a semiconductor device even at a low temperature that solidifies the coolant.

  The semiconductor power converter for electric railway of the present invention uses a variable conductance heat pipe (hereinafter abbreviated as VCHP) whose coolant is pure water in order to cool the semiconductor device. The semiconductor device is in contact with the heat receiving block, and the heat of the heat receiving block is transferred to the heat radiating fin by the VCHP, and the heat escapes from the heat radiating fin to the surrounding air.

  In the semiconductor power converter for electric railway of the present invention, conductive busses are connected to both sides or one side of the semiconductor device, and an insulating plate is inserted between the conductive busses and the heat receiving block. This insulating plate electrically insulates the semiconductor device and the conductive bus from the heat receiving block, VCHP and the heat radiating fin, and also transfers the heat of the semiconductor device to the heat receiving block, so that the VCHP and the heat radiating fin are set to the ground potential. It is possible to prevent the power receiving unit from being outside the power converter.

  Moreover, the semiconductor power converter for electric railway of the present invention uses VCHP on at least one side of the semiconductor device. On the opposite side, an inexpensive normal heat pipe may be used that is easier to manufacture than VCHP. Even if the ambient temperature is low and the normal heat pipe freezes and the cooling performance is significantly reduced, the semiconductor device can be cooled on one side using VCHP. Since the pipe also functions, the semiconductor device can be cooled from both one side using VCHP and one side using a normal heat pipe.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is external temperature lower than the freezing point of the cooling fluid of a heat pipe, the semiconductor power converter device for electric railways which enabled it to cool a semiconductor device can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1 is an explanatory diagram of this embodiment. The semiconductor power conversion circuit for electric railways of the present embodiment is similar to the circuit configuration shown in FIGS. 5 and 6 and is installed on the ground. The semiconductor power converter for electric railways of this example has a rated DC voltage of 600V to 3000V.

  The diode 11 and the thyristor 12 which are power semiconductor devices shown in FIGS. 5 and 6 generate power loss as current flows. A structure for cooling the diode 11 and the thyristor 12 is shown in FIG. In FIG. 1, reference numeral 1 denotes a semiconductor device such as a diode or a thyristor, and reference numeral 2 denotes a conductive heat receiving block for cooling the semiconductor device 1 and energizing the semiconductor device 1. Reference numeral 3 is a variable conductance heat pipe (VCHP) inserted into the heat receiving block 2, and reference numeral 4 is a radiation fin. The VCHP 3 transports the heat of the heat receiving block 2 to the radiation fins 4.

  In this embodiment, the semiconductor device 1 is a silicon diode, a silicon thyristor, a GTO or the like, and two heat receiving blocks 2 are in pressure contact with the anode electrode and the cathode electrode of the semiconductor device 1. In FIG. 1, each VCHP 3 may also serve as a connection terminal of the semiconductor device 1.

  The coolant of the VCHP 3 of this embodiment is water, and air or nitrogen gas is enclosed as a non-condensable gas. Therefore, the ambient temperature of the apparatus drops below freezing point, and the amount of heat generated by the semiconductor device 1 is small. However, heat can be transported from the heat receiving block 2 to the radiation fins 4. In addition, in the semiconductor power converter for electric railways of this embodiment, since a plurality of semiconductor devices 1 are used as shown in FIGS. 5 and 6, each semiconductor device 1 is cooled by the structure shown in FIG. Yes.

  FIG. 8 is an explanatory diagram of the inside of the VCHP 3 used in this embodiment. In FIG. 8, reference numeral 31 is a container of VCHP3, and reference numeral 32 is a coolant typified by water. Reference numeral 34 in FIG. 8 is a non-condensable gas typified by air or nitrogen. The coolant 32 and the non-condensable gas 34 are enclosed in a container 31. Reference numeral 2 in FIG. 8 denotes a heat receiving block attached to the VCHP 3. A plurality of heat radiation fins 4 are attached to the VCHP 3. The movement of the cooling liquid 32 to vaporize and condense is indicated by a broken line arrow 33 in FIG.

  The heat generated by the semiconductor device 1 such as a diode warms the heat receiving block 2. The heat of the heat receiving block 2 causes the coolant 32 to boil or vaporize via the container 31 of the VCHP 3. Although the cooling liquid 32 vaporized inside the container 31 moves to the upper part of the container 31, since the non-condensable gas 34 is accumulated in the upper part of the container 31, the vaporized cooling liquid 32 is lower than the non-condensable gas 34. Can only be reached.

  The region where the non-condensable gas 34 can accumulate inside the container 31 is determined by the pressure of the vaporized coolant 32. The pressure of the vaporized coolant 32 is defined by the amount of heat transmitted through the heat receiving block 2 and the amount of heat exiting from the radiation fins 4. That is, if the amount of heat transferred from the heat receiving block 2 is larger than the amount of heat exiting from the radiation fins 4, the pressure of the vaporized cooling liquid 32 increases, and the region of the non-condensable gas 34 is narrowed so that more heat is generated. This can be transmitted to the radiating fin 4. Conversely, when the ambient temperature of the radiating fin 4 is low and the heat radiation effect is high due to wind or the like, the pressure of the vaporized cooling liquid 32 is lowered, and the area of the non-condensable gas 34 is expanded. .

  Here, the radiation fins 4 of the VCHP are arranged above a position where the pressure of the non-condensable gas 34 and the pressure of the vapor of the coolant 32 vaporized by the heat of the heat receiving block 2 are balanced. Further, the amount of the cooling liquid 32 and the non-condensable gas 34 enclosed in the container 31 in advance so that the boundary between the vaporized cooling liquid 32 and the non-condensable gas 34 is a location where the cooling liquid 32 does not freeze. Therefore, it is possible to prevent the cooling liquid 32 from freezing in the upper part of the container 31. The non-freezing coolant 32 condenses in the upper part of the container 31, becomes liquid, returns to the lower part of the container 31, and can carry the heat received from the heat receiving block 2 to the radiation fins 4 again.

  Since the VCHP coolant 32 is pure water, when the semiconductor device 1 does not generate heat and the surrounding environment is below freezing, the coolant 32 on the heat receiving block 2 side may freeze. However, when the electric power is supplied to the semiconductor power conversion device for electric railway, the water that is the coolant 32 frozen as the semiconductor device 1 generates heat is melted and further evaporated to transport the heat of the heat receiving block 2 to the radiation fins 4.

  Since the semiconductor power conversion device for electric railways of this embodiment includes the VCHP 3, the low-temperature environment below freezing point in which pure water freezes despite the use of pure water as the coolant 32, for example, − Even at an outside air temperature of 30 ° C., the semiconductor device 1 can be cooled without hindrance without attaching a freeze prevention heater to the heat pipe.

(Example 2)
The semiconductor power conversion device of this example is shown in FIG. The difference from the first embodiment is that the heat receiving block 2, the VCHP 3 and the heat radiation fin 4 are insulated from the semiconductor device 1. Insulating plate 5 is used to insulate semiconductor device 1 from heat receiving block 2. As the insulating plate 5, an aluminum nitride (AlN) plate or an alumina (Al ₂ O ₃ ) plate having high thermal conductivity was used while maintaining electrical insulation. In order to energize the semiconductor device 1, a conductive bus 6 made of copper or a copper alloy is pressed against the anode surface and the cathode surface of the diode or thyristor that is the semiconductor device 1. Note that an electrical insulating grease or the like may be applied between the surfaces to be pressed to reduce the thermal resistance of the pressure contacting surface.

  In this embodiment, since the radiating fin 4 and the VCHP 3 are electrically insulated from the semiconductor device 1, the radiating fin 4 can be set to the ground potential or the frame potential of the casing, and the radiating fin 4 can be set to the power converter housing. There is no need to separate from a structural material such as a body frame, and the semiconductor power conversion device can be made small and highly safe.

(Example 3)
FIG. 3 shows this embodiment. This example differs from Example 1 only in that the VCHP 3 of FIG. 8 is used on one side of the semiconductor device 1 and the other side is cooled using the normal heat pipe 35 of FIG. The same as in the first embodiment.

  When the normal heat pipe 35 is used in a low temperature environment in which the coolant 32 of the heat pipe 35 is frozen, the cooling performance is remarkably deteriorated and the heat dissipation of the semiconductor device 1 is hindered. However, if only one of the anode surface and the cathode surface of the semiconductor device 1 is cooled by the VCHP 3 as in this embodiment, the semiconductor device 1 can be prevented from being thermally damaged. In addition, when the ambient temperature is high and the coolant 32 is liquid, the normal heat pipe 35 also contributes to cooling, so that the semiconductor device 1 can be cooled without problems. Thus, according to the present embodiment, an inexpensive and small semiconductor power conversion device can be realized.

Example 4
FIG. 4 shows this embodiment. This embodiment differs from the second embodiment only in that the VCHP 3 of FIG. 8 is used on one side of the semiconductor device 1 and the other side of the semiconductor device 1 is cooled using the normal heat pipe 35 of FIG. Other than that, the second embodiment is the same as the second embodiment.

  If only one of the anode surface and the cathode surface of the semiconductor device 1 is cooled by VCHP3 as in this embodiment, the semiconductor device 1 can be prevented from thermal damage, the ambient temperature is high, and the coolant 32 is When it is in a liquid state, the normal heat pipe 35 also contributes to cooling, so that the semiconductor device 1 can be cooled without problems. Thus, according to the present embodiment, an inexpensive and small semiconductor power conversion device can be realized.

Explanatory drawing of the cooling means of the semiconductor device of the power converter device of Example 1. FIG. Explanatory drawing of the cooling means of the semiconductor device of the power converter device of Example 2. FIG. Explanatory drawing of the cooling means of the semiconductor device of the power converter device of Example 3. FIG. Explanatory drawing of the cooling means of the semiconductor device of the power converter device of Example 4. FIG. Explanatory drawing of the power converter circuit for electric railways. Explanatory drawing of another electric railway power converter circuit. Explanatory drawing of the cooling means of the semiconductor device of the power converter device of a prior art. Explanatory drawing of the variable conductance heat pipe with which the power converter device of Example 1 is provided. Explanatory drawing of a normal heat pipe.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Heat receiving block, 3 ... Variable conductance heat pipe (VCHP), 4 ... Radiation fin, 5 ... Insulating plate, 6 ... Bus, 9 ... Heat receiving block, 11 ... Diode, 12 ... Thyristor, 13 ... Electric wires, 14 ... Electric railway vehicles, 21, 32 ... Coolant, 22 ... Tank, 23 ... Sleeve, 24 ... Condensing part, 31 ... Container, 34 ... Non-condensable gas, 35 ... Heat pipe.

Claims (6)

In an electric railway semiconductor power conversion device that converts AC power into electric power and converts it to DC power, or receives DC power from the electric railway and regenerates it into AC power.
The power converter comprises a plurality of power semiconductor elements for converting the AC power to DC power or regenerating DC power to AC power,
The power semiconductor element is sandwiched between conductive heat receiving block portions,
A semiconductor power conversion device for electric railway, wherein the heat receiving block portion includes a variable conductance heat pipe. In an electric railway semiconductor power conversion device that converts AC power into electric power and converts it to DC power, or receives DC power from the electric railway and regenerates it into AC power.
The power converter comprises a plurality of power semiconductor elements for converting the AC power to DC power or regenerating DC power to AC power,
The power semiconductor element is sandwiched between conductive bus members,
The conductive bus member is sandwiched between conductive heat receiving block portions,
The conductive bus member and the conductive heat receiving block are electrically insulated by an electrical insulation member,
A semiconductor power conversion device for electric railway, wherein the heat receiving block portion includes a variable conductance heat pipe. In the semiconductor power converter device for electric railways according to claim 1 or 2,
A semiconductor power converter for electric railway, comprising a variable conductance heat pipe on one side of the conductive heat receiving block portion sandwiching the power semiconductor element.   2. The semiconductor power conversion device for electric railway according to claim 1, wherein the variable conductance heat pipe is an electric connection terminal of the power semiconductor element.   3. The semiconductor power converter for electric railway according to claim 2, wherein the variable conductance heat pipe is electrically connected to a casing of the power converter.   The semiconductor power converter for electric railway according to any one of claims 1 to 3, wherein the variable conductance heat pipe uses pure water as a coolant.

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