JP2014052116A - Cooling device, electric vehicle equipped with the same, and electronic apparatus equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device which is operative even if a heat radiation part is positioned lower than a heat receiving part and thus widens an application range, and to provide an electric vehicle and an electronic apparatus which are equipped with the cooling device.SOLUTION: A cooling device includes: a heat receiving part 5 which is connected with an upper surface of a semiconductor switching element 3 in a state that heat may move; a heat radiation part 8 which is connected with an exhaust port 6 of the heat receiving part 5 through a heat radiation path 7; a feedback path 10 which connects the heat radiation part 8 with an inflow port 9 of the heat receiving part 5; a lifting pump 11 which sequentially circulates a working fluid from the upstream side of the working fluid flow to the feedback path 10; an on-off valve 12; a storage tank 13 located at a position higher than the heat receiving part 5; and a non-return valve 14 which controls the working fluid flow near the heat receiving part 5. A low water level sensor 15, which detects a drought state (lower than a water level L), and a high water level sensor 15b, which detects a full water state (equal to or higher than a water level H), are provided at the storage tank 13 as water level detection means. Control means 16, which controls the lifting pump 11 and the on-off valve 12 according to the water level detected by the water level detection means, is provided.

Description

  The present invention relates to a cooling device for an electric vehicle or an electronic device on which a power semiconductor is mounted, for example.

  Conventionally, this type of cooling device is known to be mounted on a power conversion circuit of an electric vehicle.

  In an electric vehicle, an electric motor serving as a driving power source is switched by an inverter circuit which is a power conversion circuit.

  A plurality of power semiconductors represented by power transistors are used in the inverter circuit, and a large current of several tens of amperes flows through each power semiconductor.

  For this reason, power semiconductors generate a large amount of heat and need to be cooled.

  Therefore, in the lower heat receiving portion, the heat of the power semiconductor is taken away by the refrigerant and vaporized, cooled by the heat radiating portion arranged in the upper portion, liquefied, and then dropped again in the lower portion, thereby cooling the inverter circuit. Such a cooling device has been devised (see, for example, Patent Document 1).

  However, such a cooling device is said to be a boiling type cooling type that evaporates by boiling the refrigerant in the heat receiving part, and this type receives heat in a state where the refrigerant stays in the heat receiving part. As a conclusion, it is known that the cooling performance is low.

  On the other hand, the refrigerant circulation type cooling type receives heat in a state where the refrigerant is convected in the heat receiving part, so that the efficiency of heat transfer to the refrigerant is high, and as a result, the cooling performance is drastically improved (for example, Patent Documents). 2).

  In this apparatus, the heat receiving portion, the heat radiating portion connected to the discharge port of the heat receiving portion via a heat radiating path, the feedback path connecting the heat radiating portion and the inlet of the heat receiving portion, and the feedback path are interposed. It is set as the structure provided with the non-return valve.

JP-A-8-126125 JP 2009-88127 A

  However, in the cooling device shown in Patent Document 2, since water condensed in the heat radiating section falls due to its own weight, there is a problem in that it does not operate unless the position of the heat radiating section is higher than the heat receiving section, and the application range is narrow.

  Accordingly, an object of the present invention is to provide a cooling device that operates even if the position of the heat radiating portion is lower than that of the heat receiving portion and has a wide application range.

  In order to achieve this object, the present invention provides a cooling device that circulates a working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat, The return path is provided with a pump, an on-off valve, and a storage tank that circulates the working fluid in order from the upstream side of the flow of the working fluid, and the storage tank is provided at a position higher than the heat receiving unit. A check valve for controlling the flow of the working fluid is provided in the vicinity of the heat receiving part of the return path connecting the parts, and a water level detecting means is provided in the storage tank, and the water pump detected by the water level detected by the water level detecting means And a control means for controlling the on-off valve, which achieves the initial purpose.

  As described above, the present invention is a cooling device that circulates a working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat, The pump includes a pump, an on-off valve, and a storage tank that circulates the working fluid in order from the upstream side of the fluid flow, and the storage tank is provided at a position higher than the heat receiving unit, and the return that connects the storage tank and the heat receiving unit A check valve for controlling the flow of the working fluid is provided in the vicinity of the heat receiving portion of the path, and a water level detection unit is provided in the storage tank, and the pump and the open / close valve are controlled by the water level detected by the water level detection unit Therefore, even if the position of the heat radiating portion is lower than that of the heat receiving portion and it cannot be dropped due to its own weight, the working fluid condensed in the heat radiating portion can be pushed up to the storage tank by the pump.

  That is, the cooling device of the present invention can supply the working fluid to the heat receiving portion in a timely and appropriate amount by detecting the water level by the water level detection means provided in the storage tank and maintaining the water level in the storage tank within a predetermined range.

  In addition, since the storage tank is provided between the pump and the check valve, the check valve does not directly receive the pushing pressure of the pump, and the supply of working fluid to the heat receiving part by the check valve It is done in the same way as when not using it.

  Furthermore, the on-off valve can prevent the working fluid in the return path from flowing backward and returning to the heat radiating section when the pump is stopped.

  That is, according to the configuration of the present invention, the working fluid can be circulated even when the position of the heat radiating portion is lower than the heat receiving portion, as in the case where the position of the heat radiating portion is higher than the heat receiving portion. Since performance can also be maintained, it is not limited to the height relationship between the heat receiving portion and the heat radiating portion, and the application range of the cooling target is widened.

Schematic of the electric vehicle according to the first embodiment of the present invention. Schematic showing the cooling system Block diagram of the control means Flow chart showing the control of the drying operation Schematic which shows the cooling device of Embodiment 2 of this invention.

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

(Embodiment 1)
As shown in FIG. 1, the electric motor that drives the axle of the electric vehicle 1 is connected to an inverter circuit (not shown) that is a power conversion device disposed in the vicinity of the hood 2 of the electric vehicle 1.

  The inverter circuit includes a plurality of semiconductor switching elements 3 that supply power to the electric motor as an example of a power semiconductor.

  Further, an inverter circuit (not shown), in particular, a cooling device 4 for cooling the semiconductor switching element 3 is provided.

  As shown in FIG. 2, the cooling device 4 circulates the working fluid to the heat receiving part 5, the heat radiating path 7, the heat radiating part 8, the return path 10, and the heat receiving part 5 to move heat.

  The circulation path formed by the heat receiving part 5, the heat radiation path 7, the heat radiation part 8, and the return path 10 is in a sealed state, and the internal atmosphere is in a negative pressure state from atmospheric pressure.

  Then, for example, about several hundred cc (an amount sufficiently smaller than the volume of the circulation path) of water (an example of a refrigerant) is injected into the negative pressure path. Ethylene glycol is used as a refrigerant other than water, particularly as an antifreeze in automobiles. Hereinafter, the working fluid is described as water.

  As shown in FIG. 2, the cooling device 4 includes a heat receiving part 5 connected to the upper surface of the semiconductor switching element 3 in a state where heat transfer is possible, and heat dissipation connected to the discharge port 6 of the heat receiving part 5 via a heat dissipation path 7. Part 8, a return path 10 connecting the heat radiation part 8 and the inlet 9 of the heat receiving part 5, a pumping pump 11 for circulating the working fluid in this feedback path 10 in order from the upstream side of the water flow, and an on-off valve 12 The storage tank 13 is provided at a position higher than the heat receiving section 5, and the check valve 14 for controlling the flow of water is provided in the vicinity of the heat receiving section 5. The storage tank 13 detects a drought state (below the water level L) as a water level detection means. The sensor 15a and the high water level sensor 15b which detects a full water state (water level H or more) are provided.

  Moreover, as shown in FIG. 3, the control means 16 which receives the signal from the low water level sensor 15a or the high water level sensor 15b and controls the pumping pump 11 and the on-off valve 12 is provided.

  In the above-described configuration, the cooling device 4 of the present embodiment first has the heat dissipation path 7 that is in a gas-liquid mixed state due to a rise in pressure when the water in the heat receiving portion 5 boils with the heat of the semiconductor switching element 3. To reach the heat dissipation part 8

  Next, when cooled by blowing air to the outer surface of the heat radiating unit 8 with a fan (not shown), the liquid phase state is obtained again, and the open / close valve 12 is opened by the pumping pump 11 for the water in the liquid phase state. Then, the water is transferred to the storage tank 13 and returned to the upstream side of the check valve 14 in the return path 10.

  In this state, the pressure in the heat receiving portion 5 gradually decreases, and at the next moment, the pressure due to the amount of water upstream of the check valve 14 is higher than the pressure in the heat receiving portion 5. When it becomes higher, the check valve 14 is opened.

  As a result, the water upstream of the check valve 14 flows into the heat receiving part 5, and at the next moment, the water is explosively vaporized in the heat receiving part 5, and the semiconductor switching element 3 is caused by this heat of vaporization. It will be cooled effectively.

  The feature of this embodiment is that the pumping pump 11 and the on-off valve 12 are controlled by the water level detected by the low water level sensor 15a or the high water level sensor 15b in the storage tank 13, and the amount of water upstream of the check valve 14, that is, This is to stably secure the amount of water to be supplied into the heat receiving unit 5 and will be described below.

  First, the necessity of the pumping pump 11 will be described.

  In the cooling device of Patent Document 2, since the heat radiating unit 8 is located above the heat receiving unit 5, the water condensed in the heat radiating unit 8 falls due to its own weight. The movement of water from the heat receiving unit 5 to the heat radiating unit 8 is performed by the pressure difference as described above, and the water is not powered to the heat receiving unit 5, the heat radiating path 7, the heat radiating unit 8, the return path 10, and the heat receiving unit 5. Circulate with.

  However, when the cooling device 4 of Patent Document 2 is to be mounted on the electric vehicle 1 as in the present embodiment, the positions of the heat receiving part 5 and the heat radiating part 8 in the height direction are reversed, and the inside of the return path 10 The water cannot be moved without power.

  For this reason, the pumping pump 11 is newly provided and the water in the return path 10 is moved.

  Next, the control content of the control means 16 is demonstrated using the flowchart of FIG.

  When the cooling device 4 is mounted for the first time (power is turned on), the water pump 11 is stopped, the on-off valve 12 is closed, and water is stored only in the lower portion of the cooling device 4. The low water level sensor 15a is OFF, that is, the water level is less than L.

  When the control means 16 receives the OFF signal of the low water level sensor 15 a, it sends an open signal to the on-off valve 12 and simultaneously sends an operation signal to the pumping pump 11.

  By the operation of the pumping pump 11, the water accumulated in the heat radiating section 8 passes through the open on-off valve 12, is transferred to the storage tank 13 through the return path 10, the water level in the storage tank 13 rises, and the L water level is increased. Over.

  When the high water level sensor 15b detects that the water level has reached the H level indicating a full water state, the pump 12 is stopped and the open / close valve 12 is closed simultaneously.

  By closing the on-off valve 12, the water accumulated at a higher position than the water level in the heat radiating part 8 in the return path 10 flows back to the heat radiating part 8, the water level in the heat radiating part 8 rises, and the heat radiating capacity decreases. Can be prevented.

  In FIG. 2, water accumulates in the storage tank 13, the pumping pump 11 is stopped, and the open / close valve 12 is closed, so that water (including gas) moves only in the heat radiation path 7, The presence of water (liquid) in the tank 13 and the heat receiving part 5 is illustrated in a dot region.

  In this way, the control means 16 receives the signal from the low water level sensor 15a or the high water level sensor 15b and controls the pumping pump 11 and the on-off valve 12 to keep the water level in the storage tank 13 at or above the L water level, and the heat receiving section 5 Water can be stably supplied to the inside. Therefore, the semiconductor switching element 3 is sufficiently cooled and can maintain the desired characteristics.

  That is, according to the configuration of the present invention, even when the position of the heat radiating portion is lower than the heat receiving portion, the working fluid can be circulated in the same manner as when the position of the heat radiating portion is higher than the heat receiving portion. Since performance can also be maintained, it is not limited to the height relationship between the heat receiving portion and the heat radiating portion, and the application range of the cooling target is widened.

(Embodiment 2)
FIG. 5 shows an embodiment when the pumping pump 11 is operated continuously. In FIG. 5, the same components as those in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, the on-off valve 12 is provided in a bypass path 17 that branches from the return path 10 in the downstream vertical direction of the pumping pump 11 and returns to the lower part of the heat radiating unit 8, and the control means 16 includes only the on-off valve 12. I have control. In the flowchart of FIG. 4, there is no pumping pump 11, and the opening / closing operation of the opening / closing valve 12 is reversed.

  In the above configuration, when the cooling device 4 is installed for the first time (power is turned on), the water pump 11 is in operation, the on-off valve 12 is open, and water is stored only in the lower part of the cooling device 4. The low water level sensor 15a in the tank 13 is OFF, that is, the water level is less than L.

  When the control means 16 receives the OFF signal of the low water level sensor 15 a, it transmits a closing signal to the on-off valve 12. As a result, the water that has returned from the pumping pump 11 to the heat dissipating unit 8 via the open / close valve 12 and the bypass path is transferred to the storage tank 13 through the return path 10 when the open / close valve 12 is closed. The water level in the tank 13 rises and exceeds the L water level.

  When the high water level sensor 15b detects that the water level has reached the H level indicating a full water state, the on-off valve 12 is opened.

  By opening the on-off valve 12, the water pushed out from the pumping pump 11 is not sent to the higher storage tank 13 in the return path 10 but flows to the lower bypass path and returns to the heat radiating unit 8. That is, the water pump 11, the on-off valve 12, the heat radiating unit 8, and the water pump 11 are circulated.

  Thus, by continuously operating the pumping pump 11, the time from when the OFF signal of the low water level sensor 15a is received until the water reaches the storage tank 13 is the stop of the pumping pump 11 of the first embodiment. Compared to driving from the state, it can be shortened.

  According to the present embodiment, it is possible to provide a cooling device that has an effect of being able to quickly transfer water to the storage tank 13 when the detection of a drought state is delayed, such as when the accuracy of the low water level sensor 15a is low.

  As described above, the cooling device of the present invention is a cooling device that circulates a working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part, and moves the heat. A pump for circulating the working fluid in order from the upstream side of the flow of the working fluid, an on-off valve, and a storage tank, the storage tank being provided at a position higher than the heat receiving unit, and connecting the storage tank and the heat receiving unit A check valve for controlling the flow of the working fluid is provided in the vicinity of the heat receiving portion of the return path, and a water level detection unit is provided in the storage tank, and the pump and the open / close pump are opened and closed by a water level detected by the water level detection unit. The valve is controlled.

  For this reason, even if the position of the heat radiating portion is lower than that of the heat receiving portion and cannot be dropped due to its own weight, the working fluid condensed in the heat radiating portion by the pump can be pushed up to the storage tank.

  That is, the cooling device of the present invention can supply the working fluid to the heat receiving part in a timely and appropriate amount by detecting the water level by the water level detecting means provided in the storage tank and maintaining the water level in the storage tank within a predetermined range.

  Therefore, even if the position of the heat radiating part is lower than the heat receiving part, the working fluid can be circulated and the cooling performance as a cooling device can be maintained as when the position of the heat radiating part is higher than the heat receiving part. , Not limited to the height relationship between the heat receiving part and the heat radiating part, the applicable range of the cooling object is widened, the cooling device of the power conversion device as the drive device of the electric vehicle, the cooling of the high-speed arithmetic processing device part of the electronic equipment, etc. It becomes useful as a device.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Bonnet 3 Semiconductor switching element 4 Cooling device 5 Heat receiving part 6 Outlet 7 Heat radiation path 8 Heat radiation part 9 Inlet 10 Return path 11 Water pump 12 Opening / closing valve 13 Storage tank 14 Check valve 15a Low water level sensor 15b High water level Sensor 16 Control means 17 Bypass path

Claims (6)

A cooling device that circulates working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat,
The return path includes a pump, a switching valve, and a storage tank that circulate the working fluid in order from the upstream side of the flow of the working fluid,
The storage tank is provided at a position higher than the heat receiving portion, and includes a check valve that controls the flow of the working fluid in the vicinity of the heat receiving portion of the return path connecting the storage tank and the heat receiving portion,
A cooling apparatus comprising a water level detection means in the storage tank, and a control means for controlling the pump and the on-off valve according to the water level detected by the water level detection means. The cooling device according to claim 1, wherein the pump and the on-off valve are disposed below the lower end of the heat dissipating part in the return path. A cooling device that circulates working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat,
A lift pump that circulates the working fluid in order from the upstream side of the flow of the working fluid in the return path, a storage tank at a position higher than the heat receiving section, an on-off valve in a bypass path that bypasses the pump, and the vicinity of the heat receiving section And a check valve for controlling the flow of the working fluid.
A cooling apparatus comprising a water level detection means in the storage tank, and a control means for controlling the on-off valve according to the water level detected by the water level detection means. The cooling device according to claim 3, wherein the pump is disposed below the lower end of the heat dissipating part in the return path. An electric vehicle that mounts the cooling device according to any one of claims 1 to 4 and that cools a power changing device that drives an electric motor that drives an axle. An electronic device that mounts the cooling device according to claim 1 and cools a heating element.

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