JP2012023111A - Cooling device and electrical machine including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device which has high cooling performance and suppresses vibration noise of a compressor.SOLUTION: A cooling device cools a semiconductor component 13 which is a cooled object. The cooling device includes a piezoelectric element 1 converting vibration energy generated by vibration of a compressor 9 into electric energy, and a thermoelectric transducer 2. A power source of the thermoelectric transducer 2 during cooling operation is the electric energy output from the piezoelectric element 1.

Description

  The present invention relates to a cooling device that cools an object to be cooled, and an electrical apparatus including the same.

  Some control circuits for electrical equipment include semiconductor components that generate a large amount of heat. If a semiconductor component having a large amount of heat generation is not sufficiently radiated, the semiconductor component is destroyed, and as a result, the reliability of the electrical device on which the semiconductor component is mounted is impaired.

  Therefore, in order to cool a semiconductor component having a large calorific value, a method is generally employed in which heat from the semiconductor component is conducted to a heat sink having a radiation fin and the heat is released from the radiation fin.

JP 2003-63240 A JP-T-2004-501440

  If the amount of heat radiation to be secured is large, it can be dealt with by basically increasing the size of the radiation fin, but there is a limit to the increase in size of the radiation fin due to the problem of the storage space. For this reason, for example, with respect to cooling of semiconductor components with large calorific value mounted on an outdoor unit of a separation type air conditioner, there is a problem that cooling performance is not sufficient with cooling using only a heat sink in the structure of the current outdoor unit. there were.

  In addition, for example, in a separation type air conditioner, a compressor that compresses refrigerant is mounted in an outdoor unit in order to ensure sufficient cooling and heating capacity, but a large vibration noise is generated by the operation of the compressor. There was a problem of end.

  An object of this invention is to provide the cooling device which has high cooling performance, and can suppress the vibration sound of a compressor, and an electric apparatus provided with the same in view of said situation.

  In order to achieve the above object, a cooling device according to the present invention includes a piezoelectric element that converts vibration energy generated by vibration of a compressor into electric energy, and a thermoelectric conversion element. The power source is electric energy output from the piezoelectric element.

  According to such a configuration, the object to be cooled can be cooled by the cooling operation of the thermoelectric conversion element, so that the cooling performance can be enhanced. Moreover, according to such a structure, since the piezoelectric element converts the vibration energy generated by the vibration of the compressor into electric energy, the vibration noise of the compressor can be suppressed. Further, according to such a configuration, energy necessary for causing the thermoelectric conversion element to perform the cooling operation is obtained from power generation by the piezoelectric element to which the vibration of the compressor is transmitted, so that energy is saved.

  Moreover, it is desirable to provide a switching unit that switches between the cooling operation and the power generation operation of the thermoelectric conversion element by switching the direction of the current flowing through the thermoelectric conversion element.

  According to such a configuration, when the cooling operation of the thermoelectric conversion element is not necessary, the thermoelectric conversion element can perform a power generation operation, which further saves energy.

  A determination unit configured to determine whether or not the temperature of the object to be cooled exceeds a predetermined temperature; and when the determination unit determines that the temperature of the object to be cooled exceeds a predetermined temperature, the switching unit It is desirable that the operation of the thermoelectric conversion element is switched from the power generation operation to the cooling operation.

  According to such a configuration, when the temperature of the object to be cooled exceeds a predetermined temperature and a high cooling capacity is required, the operation of the thermoelectric conversion element becomes a cooling operation, and the cooling capacity automatically increases.

  In addition, it is preferable that the determination unit determine whether or not the temperature of the object to be cooled exceeds a predetermined temperature by determining whether or not the value of the current flowing through the thermoelectric conversion element exceeds a threshold value.

  According to such a configuration, a temperature sensor for measuring the temperature of the object to be cooled becomes unnecessary, so that an increase in cost can be suppressed.

  In order to achieve the above object, an electric apparatus according to the present invention includes a compressor, an object to be cooled, and a cooling device having any one of the above structures for cooling the object to be cooled.

  Moreover, in the said electric equipment, it is desirable to provide a heat sink and to provide the thermoelectric conversion element which is a component of the said cooling device between the said heat sink and the said to-be-cooled object.

  According to such a configuration, the object to be cooled can be cooled by the heat sink even when the thermoelectric conversion element which is a component of the cooling device is not performing the cooling operation.

  Moreover, as an example of the electric device, a separation type air conditioner can be cited. When the electric device is a separation-type air conditioner, the compressor, the object to be cooled, and the cooling device may be provided in an outdoor unit of the separation-type air conditioner.

  According to the present invention, the object to be cooled can be cooled by the cooling operation of the thermoelectric conversion element, so that the cooling performance can be enhanced. Further, according to the present invention, since the piezoelectric element converts vibration energy generated by vibration of the compressor into electric energy, vibration noise of the compressor can be suppressed.

It is a figure which shows schematic structure of the cooling device which concerns on one Embodiment of this invention. It is a figure which shows the schematic structural example of a thermoelectric conversion element. It is a flowchart which shows operation | movement of the cooling device which concerns on one Embodiment of this invention shown in FIG. It is a figure which shows schematic structure of the cooling device which concerns on one Embodiment of this invention. It is a figure which shows the schematic structural example of a separation-type air conditioner.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a cooling device according to an embodiment of the present invention. A cooling device according to an embodiment of the present invention includes a piezoelectric element 1, a thermoelectric conversion element 2, a diode bridge circuit 3, a smoothing capacitor 4, a backflow prevention diode 5, a first relay 6, and a second relay 7. A current transformer CT and a microcomputer 8.

  A cooling device according to an embodiment of the present invention shown in FIG. 1 is used together with a compressor 9, a DC fan 10, and a semiconductor component 13. The DC fan 10 is used for air-cooling the heat sink 12, for example.

  The compressor 9 has three legs at the bottom. Two anti-vibration rubbers 11 are sandwiched between each leg portion of the compressor 9 and an installation surface of the compressor 9 (for example, a bottom surface of a housing of an electric device), and a piezoelectric element is further interposed between the two anti-vibration rubbers 11. 1 is pinched. By providing the anti-vibration rubber 11, it is possible to suppress the vibration of the compressor 9 from being transmitted to the installation surface of the compressor 9.

  The piezoelectric element 1 converts vibration energy generated by vibration of the compressor 9 into electric energy. Such energy conversion can suppress vibration noise of the compressor 9.

  The three piezoelectric elements 1 are connected in parallel to the input side of the diode bridge circuit 3. The smoothing capacitor 4 is provided on the output side of the diode bridge circuit 3 and smoothes the output voltage of the diode bridge circuit 3. The positive polarity side of the smoothing capacitor 4 is connected to the positive end of the DC fan 10 via the backflow prevention diode 5 and the first relay 6, and the negative polarity side of the smoothing capacitor 4 is connected to the negative end of the DC fan 10.

  The first contact a and the third contact c of the second relay 7 are connected to the negative end of the DC fan 10, and the second contact b of the second relay 7 is connected between the cathode of the backflow prevention diode 5 and the first relay 6. Connected to the connection point. The first pole d of the second relay 7 is connected to the first electrode 21 of the thermoelectric conversion element 2, and the second pole e of the second relay 7 is connected to the second electrode 22 of the thermoelectric conversion element 2.

  The current transformer CT is provided between the thermoelectric conversion element 2 and the second relay 7 in order to detect the current of the thermoelectric conversion element 2. The microcomputer 8 controls the first relay 6 and the second relay 7 according to the detected current of the current transformer CT.

  The thermoelectric conversion element 2 is provided between a heat sink 12 having heat radiation fins and a semiconductor component 13 having a large heat generation amount. More specifically, the electric insulator 26 (not shown in FIG. 1) of the thermoelectric conversion element 2 and the heat sink 12 are in contact with each other, and the electric insulator 27 (not shown in FIG. 1) of the thermoelectric conversion element 2 and the semiconductor component 13 are connected. The thermoelectric conversion element 2 is provided so as to be in contact with the copper plate 14. Examples of the semiconductor component 13 include an IPM (Intelligent Power Module) for driving the compressor 9 and a DB (Diode Bridge) for driving the compressor 9. In FIG. 1, for convenience of illustration, the heat sink 12, the thermoelectric conversion element 2, the copper plate 14, and the semiconductor component 13 are illustrated separately for the sake of convenience.

  Here, the example of schematic structure of the thermoelectric conversion element 2 is shown in FIG. The thermoelectric conversion element 2 shown in FIG. 2 includes a first electrode 21, a second electrode 22, a P-type semiconductor 23, a metal electrode 24, and an N-type semiconductor 25. The first electrode 21 is connected to the N-side end of the unit in which the P-type semiconductor 23 and the N-type semiconductor 25 are alternately connected in series via the metal electrodes 24, and the second electrode 22 is connected to the P-side end of the unit. Is connected. Further, the unit is sandwiched between electrical insulators 26 and 27 having high thermal conductivity.

  The operation of the cooling device according to an embodiment of the present invention having the above-described configuration will be described with reference to the flowchart shown in FIG.

  The flow operation shown in FIG. 3 is started when the power supply of the electric device in which the cooling device, the compressor 9, the DC fan 10, and the semiconductor component 13 according to the embodiment of the present invention are turned on. . At the start of the flow operation, the first relay 6 is in a conductive state between the contact and the pole as shown in FIG. 1, and the second relay 7 is in the conductive state between the first contact a and the first pole d as shown in FIG. The second contact b and the second pole e are in a conductive state.

  In step S10, the operation of the semiconductor component 13 and the power generation operation of the thermoelectric conversion element 2 are started. When the electric device is turned on, power is supplied to the semiconductor component 13 and the semiconductor component 13 starts to operate. As a result, heat generation from the semiconductor component 13 starts, and the temperature on the semiconductor component 13 side becomes higher than that on the heat sink 12 side. In addition, since the first contact a and the first pole d of the second relay 7 are in a conductive state and the second contact b and the second pole e of the second relay 7 are in a conductive state, the second contact of the thermoelectric conversion element 2 is performed. The potential of the first electrode 21 is not higher than the potential of the second electrode 22 of the thermoelectric conversion element 2. Thus, since the semiconductor component 13 side is higher in temperature than the heat sink 12 side, and the potential of the first electrode 21 of the thermoelectric conversion element 2 is not higher than the potential of the second electrode 22 of the thermoelectric conversion element 2, The thermoelectric conversion element 2 starts a power generation operation.

  In step S20 following step S10, the operation of the compressor 9 and power generation by the piezoelectric element 1 are started. The compressor 9 is driven by the operation of the semiconductor component 13, and the compressor 9 starts to operate. Thereby, vibration transmission to the piezoelectric element 1 starts, and the piezoelectric element 1 starts a power generation operation. The output voltage of the piezoelectric element 1 is rectified by the diode bridge circuit 3 and smoothed by the smoothing capacitor 4.

  In step S30 following step S20, the operation of the DC fan 10 is started. Since the contact and the pole of the first relay 6 are in a conductive state, the DC voltage obtained by rectifying and smoothing the voltage obtained by the power generation operation of the piezoelectric element 1 and the DC obtained by the power generation operation of the thermoelectric conversion element 2 are used. The voltage is supplied to the DC fan 10, and the DC fan 10 starts to operate.

  In step S40 following step S30, the microcomputer 8 determines whether or not the detected current value of the current transformer CT exceeds a threshold value stored in advance. As the temperature of the semiconductor component 13 rises, the temperature difference between the semiconductor component 13 side and the heat sink 12 side increases, and the current output from the thermoelectric conversion element 2 increases. Therefore, the determination as to whether or not the detected current value of the current transformer CT exceeds the threshold value indirectly determines whether or not the temperature of the semiconductor component 13 exceeds a predetermined temperature.

  If the detected current value of the current transformer CT does not exceed the threshold value (No in step S40), the determination of whether or not the detected current value of the current transformer CT exceeds the threshold value is continued.

  On the other hand, if the detected current value of the current transformer CT exceeds the threshold value (Yes in step S40), the microcomputer 8 changes the state of the first relay 6 and the second relay 7 from the state shown in FIG. 1 to FIG. The state is switched (step S50). In the state shown in FIG. 4, the first relay 6 is in a disconnected state between the contact and the pole, and the second relay 7 is in the conductive state between the second contact b and the first pole d, and the third contact c and the second pole. e is a conduction state. Since the contact and the pole of the first relay 6 are in the cut-off state, the energization to the DC fan 10 is cut off, and the operation of the DC fan 10 is stopped. In addition, since the second contact b and the first pole d of the second relay 7 are in a conductive state and the third contact c and the second pole e of the second relay 7 are in a conductive state, the power generation operation of the piezoelectric element 1 is performed. The DC voltage obtained by rectifying and smoothing the voltage obtained by the above is applied to the thermoelectric conversion element 2, and the potential of the first electrode 21 of the thermoelectric conversion element 2 becomes higher than the potential of the second electrode 22 of the thermoelectric conversion element 2. . Thereby, the thermoelectric conversion element 2 starts cooling operation.

  In step S60 following step S50, the microcomputer 8 determines whether or not a predetermined time has elapsed since the state of the first relay 6 and the second relay 7 was switched from the state shown in FIG. 1 to the state shown in FIG. .

  If the predetermined time has not passed since the state of the first relay 6 and the second relay 7 was switched from the state shown in FIG. 1 to the state shown in FIG. 4 (No in step S60), the first relay 6 and the second relay 7 1 is continued from the state shown in FIG. 1 to the state shown in FIG.

  On the other hand, if the predetermined time has elapsed since the state of the first relay 6 and the second relay 7 was switched from the state shown in FIG. 1 to the state shown in FIG. 4 (Yes in step S60), the microcomputer 8 The state of the relay 6 and the second relay 7 is returned to the state shown in FIG. 1 (step S70). Thereby, the operation of the thermoelectric conversion element 2 returns from the cooling operation to the power generation operation, and the operation of the DC fan 10 is resumed. Then, the process returns to step S40.

  By performing the above-described operation, the cooling device according to the embodiment of the present invention performs cooling using only the heat sink 12 as in the conventional case when the temperature of the semiconductor component 13 having a large calorific value is equal to or lower than a predetermined temperature. When the temperature of the semiconductor component 13 having a large calorific value exceeds a predetermined temperature, the semiconductor component 13 having a large calorific value is cooled by the thermoelectric conversion element 2 and the electric power that is a power source of the thermoelectric conversion element 2 is compressed. The energy is generated from the energy generated by the piezoelectric element 1 attached to the lower part of the machine 9.

  Since the cooling device according to the embodiment of the present invention can cool the semiconductor component 13 (the object to be cooled) having a large heat generation amount by the cooling operation of the thermoelectric conversion element 2, the cooling performance can be enhanced. Moreover, since the cooling device according to the embodiment of the present invention converts the vibration energy generated by the vibration of the compressor 9 into electric energy, the piezoelectric element 1 can suppress vibration noise of the compressor 9.

  Furthermore, the cooling device according to the embodiment of the present invention obtains energy necessary for causing the thermoelectric conversion element 2 to perform a cooling operation from power generation by the piezoelectric element 1 to which vibration of the compressor 9 is transmitted. It becomes energy saving. Note that Patent Document 1 discloses a cooling device that applies a voltage generated by pressurizing a piezoelectric element to the Peltier element to cause the Peltier element to perform a cooling operation. However, the cooling apparatus disclosed in Patent Document 1 is disclosed. Is a configuration that requires an airtight container filled with a gas adsorbing substance, and does not save energy by utilizing the vibration of the compressor 9.

  Further, by performing the above-described operation, the cooling device according to the embodiment of the present invention causes the thermoelectric conversion element 2 to perform a power generation operation when the temperature of the semiconductor component 13 having a large calorific value is equal to or lower than a predetermined temperature. The energy generated by the thermoelectric conversion element 2 is used as a power source for the DC fan 10. This further saves energy.

  Note that the DC fan 10 can be used for cooling the inside of a control box in which a control board (a control board on which a compressor driving motor driving circuit or the like is mounted) is housed. When the DC fan 10 is used for cooling the inside of a control box containing a control board (a control board on which a compressor driving motor drive circuit or the like is mounted), the cooling device according to an embodiment of the present invention is as follows. It has the following advantages.

  When the semiconductor component 13 is an IPM for driving the compressor 9, when the compressor 9 stops, power generation by the piezoelectric element 1 is stopped and no power is supplied to the IPM, so that the IPM does not generate heat. However, since the IPM has heat for a while even if it is not energized, the power generation operation of the thermoelectric conversion element 2 is continued for a while.

  The cooling device according to the embodiment of the present invention can drive the DC fan 10 with the DC voltage obtained by the power generation operation of the thermoelectric conversion element 2 even after the compressor 9 is stopped. The inside cooling can be continued, which is preferable.

  The cooling device according to the present invention is not limited to the configuration of the cooling device according to the embodiment of the present invention described above.

  For example, the above-described cooling device according to an embodiment of the present invention is assumed to be used with a compressor 9 of a type in which vibrations at the respective legs are substantially the same, and the output voltages of the three piezoelectric elements 1 are Since they are substantially the same, the three piezoelectric elements 1 are connected in parallel to the input side of the diode bridge circuit 3. When the output voltages of the plurality of piezoelectric elements 1 are different from each other, for example, a configuration in which the plurality of piezoelectric elements 1 are directly connected to the input side of the diode bridge circuit 3 may be employed.

  For example, in the cooling device according to the embodiment of the present invention described above, the DC voltage supply destination obtained by rectifying and smoothing the voltage obtained by the power generation operation of the piezoelectric element 1 and the power generation operation of the thermoelectric conversion element 2 are used. The DC voltage supply destination obtained is the DC fan 10, but a load other than the DC fan 10 may be used. Further, the supply destination of the DC voltage obtained by rectifying and smoothing the voltage obtained by the power generation operation of the piezoelectric element 1 and the supply destination of the DC voltage obtained by the power generation operation of the thermoelectric conversion element 2 are different from each other. There may be.

  For example, in the cooling device according to the embodiment of the present invention described above, it is indirectly determined whether the temperature of the semiconductor component 13 has exceeded a predetermined temperature by determining whether the detected current value of the current transformer CT has exceeded a threshold value. However, a temperature sensor such as a thermistor is provided in the vicinity of the semiconductor component 13 instead of the current transformer CT, and the temperature of the semiconductor component 13 is determined by determining whether or not the detected value of the temperature sensor exceeds the threshold value. You may make it determine directly whether it exceeded the predetermined temperature.

  The cooling device according to the present invention is preferably mounted on an electric device having an object to be cooled and a compressor. An example of such an electric device is a separation type air conditioner. As described above, with regard to cooling of semiconductor components with large heat generation mounted on the outdoor unit of the separation type air conditioner, there is a problem that cooling performance is not sufficient by cooling using only the heat sink in the structure of the current outdoor unit. Therefore, it is preferable to mount the cooling device according to the present invention on the outdoor unit of the separation type air conditioner.

  Here, the example of schematic structure of a separation-type air conditioner is shown in FIG. The separation type air conditioner shown in FIG. 5 includes an indoor unit 102 and an outdoor unit 103. The indoor unit 102 and the outdoor unit 103 are each driven by a commercial AC power source 101. A detailed description of the indoor unit 102 will be omitted, and the outdoor unit 103 will be described below.

  The outdoor unit 103 includes an AC-DC converter 104, a compressor drive motor drive circuit 105, an outdoor fan drive motor drive circuit 106, a DC-DC converter 107, a microcomputer 108, and a compressor drive motor 109. And an outdoor fan driving motor 110, a compressor (not shown) driven by the compressor driving motor 109, and an outdoor fan (not shown) driven by the outdoor fan driving motor 110.

  The AC-DC converter 104 converts the output voltage of the commercial AC power supply 101 supplied via the indoor unit 102 into a DC voltage, and the compressor driving motor driving circuit 105 and the outdoor fan driving motor driving circuit 106. And the DC-DC converter 107. The compressor drive motor drive circuit 105 drives the compressor drive motor 109 according to instructions from the microcomputer 108, and the outdoor fan drive motor drive circuit 106 drives the outdoor fan drive motor 110 according to instructions from the microcomputer 108. The compressor driving motor driving circuit 105 and the outdoor fan driving motor driving circuit 106 are each insulated from the microcomputer 108 by a photocoupler. The DC-DC converter 107 steps down the input voltage to generate a power supply voltage for the microcomputer 108 and supplies it to the microcomputer 108. Note that the input side and the output side of the DC-DC converter 107 are insulated by, for example, an insulating transformer (not shown) provided in the DC-DC converter 107. The microcomputer 108 performs operation control of the outdoor unit 103 and communication with a microcomputer (not shown) of the indoor unit 102. Note that a photocoupler for preventing the microcomputer 108 and the microcomputer (not shown) of the indoor unit 102 from being electrically connected via a communication line is provided on the outdoor unit 103 side.

  When the above-described cooling apparatus according to the embodiment of the present invention is mounted on the separation type air conditioner having the above-described configuration, it is desirable that the microcomputer 108 has the function of the microcomputer 8.

DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Thermoelectric conversion element 3 Diode bridge circuit 4 Smoothing capacitor 5 Backflow prevention diode 6 1st relay 7 2nd relay 8 Microcomputer 9 Compressor 10 DC fan 11 Anti-vibration rubber 12 Heat sink 13 Semiconductor component 14 Copper plate 21 1st electrode 22 Second electrode 23 P-type semiconductor 24 Metal electrode 25 N-type semiconductor 26, 27 Electrical insulator 101 AC power supply 102 Indoor unit 103 Outdoor unit 104 AC-DC converter 105 Motor drive circuit for driving compressor 106 Motor drive for driving outdoor fan Circuit 107 DC-DC converter 108 Microcomputer 109 Outdoor fan drive motor 110 Compressor drive motor CT Current transformer

Claims (7)

A piezoelectric element that converts vibration energy generated by the vibration of the compressor into electrical energy;
A thermoelectric conversion element,
A cooling device, wherein a power source of the thermoelectric conversion element during cooling operation is electric energy output from the piezoelectric element.   The cooling device according to claim 1, further comprising a switching unit that switches between a cooling operation and a power generation operation of the thermoelectric conversion element by switching a direction of a current flowing through the thermoelectric conversion element. A determination unit for determining whether the temperature of the object to be cooled exceeds a predetermined temperature;
The operation of the thermoelectric conversion element is switched from a power generation operation to a cooling operation by the switching unit when the determination unit determines that the temperature of the object to be cooled exceeds a predetermined temperature. Cooling system.   The determination unit determines whether or not a temperature of the object to be cooled exceeds a predetermined temperature by determining whether or not a value of a current flowing through the thermoelectric conversion element exceeds a threshold value. Item 4. The cooling device according to Item 3. A compressor,
The object to be cooled,
An electrical apparatus comprising: the cooling device according to claim 1 that cools the object to be cooled. With a heat sink,
The electric device according to claim 5, wherein a thermoelectric conversion element that is a component of the cooling device is provided between the heat sink and the object to be cooled. The electrical device is a separation type air conditioner,
The electric device according to claim 5 or 6, wherein the compressor, the object to be cooled, and the cooling device are provided in an outdoor unit of the separation type air conditioner.

Images