JP2006211805A - Switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of protecting a gate drive circuit board and a signal line connected to a switching element consisting of a wide gap semiconductor element of high temperature operation from the heat of switching element. <P>SOLUTION: A power convertor 14 stores a switching element 11 consisting of a wide gap semiconductor and a gate drive circuit board 12 which is connected to the switching element 11 to supply a drive signal to the switching element 11 in a housing 15, and converts a DC voltage into AC voltage by on/off operation of switching element, which is supplied to a load. A signal line 13 that transmits the drive signal from the gate drive circuit board 12 to the switching element 11 of an inverter circuit, comprises a flat conductor having heat dissipation characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a switching device, for example, a cooling device in a power conversion device that incorporates a switching element composed of a wide gap semiconductor capable of high-temperature operation, and converts a DC voltage into an alternating current by an on / off operation of the switching device to supply power to a load. Concerning structure.

  For example, a power conversion device incorporated in a large-capacity UPS or a battery power storage system includes an inverter device 4 that outputs a set frequency and voltage as shown in FIG. This inverter device 4 converts a DC voltage from a DC power source such as a solar cell or a fuel cell into an AC by an on / off operation of the switching element 1 and supplies power to a load. The output frequency command and the voltage command in the inverter device 4 are applied to the switching element 1 by transmitting a drive signal output from the gate drive circuit board 2 to the gate terminal 5 of the switching element 1.

  In FIG. 7, as shown by the solid line in the figure, the one-phase inverter device 4 is configured by the one-phase (U-phase) switching element 1 and its gate drive circuit board 2 that form a pair in the upper and lower sides. As shown, if the remaining two-phase (V-phase, W-phase) switching elements 1 and the gate drive circuit board 2 that are paired up and down are added, a three-phase inverter device 4 is formed.

  Here, as the switching element 1 incorporated in the inverter device 4 described above, a semiconductor element made of silicon, for example, a Si-GTO element (gate turn-off thyristor) or the like is generally used. This type of switching element 1 has a maximum operating temperature of about 150 ° C. (about 100 ° C. or less in actual use), and this temperature is also within an allowable temperature for components mounted on the gate drive circuit board 2. Therefore, the components of the gate drive circuit board 2 can be used.

  Therefore, a structure is adopted in which the gate terminal 5 of the switching element 1 is directly connected to the gate drive circuit board 2 by connector connection or the like, or is connected to the gate drive circuit board 2 through the communication vinyl signal line 3. ing.

In addition, the switching element 1 and the gate drive circuit board 2 have a structure housed in the housing of the inverter device 4. In order to suppress a steady loss of the switching element 1 and a temperature increase due to the switching loss, the switching element 1 Generally, a cooling structure using the heat sink or the fan is adopted by attaching a heat sink or by providing a fan in the housing corresponding to the place where the switching element 1 is disposed (for example, , See Patent Document 1).
JP 2003-259658 A

  By the way, as the switching element 1 incorporated in the inverter device 4 described above, a silicon semiconductor element, for example, a Si-GTO element has been conventionally used. However, as a replacement for the silicon semiconductor element in recent years, a wide gap semiconductor is used. A switching element 1 composed of an element, for example, a semiconductor element made of silicon carbide (for example, a SiC-GTO element) is being used.

  Since this wide gap semiconductor element has the characteristics of high breakdown voltage, low loss and high temperature operation, a heat sink or fan for cooling the element provided to suppress a steady loss of the switching element 1 or a temperature rise due to the switching loss. Is no longer necessary. As a result, when this wide gap semiconductor element is used, it is easy to reduce the loss and size of the inverter device 4 and it is effective in that a compact high-performance inverter device 4 can be provided.

  However, when the switching element 1 composed of the wide gap semiconductor element described above is turned on / off at a high temperature (about 400 ° C.), the heat generated from the switching element 1 is transmitted through the signal line 3 to the gate drive circuit. It is transmitted to the substrate 2. As a result, there is a possibility that the signal line 3 is melted by heat, or the gate drive circuit board 2 is malfunctioned or destroyed by heat.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and its object is to provide a signal line and a gate drive circuit substrate connected to a switching element made of a wide gap semiconductor element capable of operating at high temperature. An object of the present invention is to provide a switching device having a structure capable of protecting from heat by the switching element.

  As technical means for achieving the above object, the present invention includes a switching element composed of a wide gap semiconductor, and a gate driving circuit board connected to the switching element and applying a driving signal to the switching element. In the switching device that is stored inside and controls the on / off operation of the switching element by the driving signal, the signal line for transmitting the driving signal from the gate driving circuit board to the switching element is configured by a plate-like conductor having heat dissipation. It is characterized by.

  In the power conversion device according to the present invention, the signal line for transmitting the drive signal from the gate drive circuit board to the switching element is configured by a plate-like conductor having heat dissipation, so that the switching line and the gate drive circuit board are interposed. A temperature gradient can be developed. In addition, the heat dissipation area is increased and a large heat dissipation effect is exhibited. Further, it is easy to reduce the wiring inductance due to the conductor.

  As a result, the heat of the switching element generated due to the steady loss of the switching element and the temperature rise due to the switching loss is quickly dissipated to the surrounding space by the signal line, so that it is accumulated in the signal line itself or the signal Transmission to the gate drive circuit substrate connected via the line can be suppressed.

  In the above-described configuration, it is desirable that the signal line adopts an overlapping structure including a pair of plate conductors and a dielectric interposed between the pair of plate conductors. If the structure is such that a dielectric is sandwiched between a pair of plate-like conductors, the inductance component of the conductor itself can be canceled by the capacitance component of the dielectric.

  By adopting a superposition structure of a pair of plate conductors and dielectric as the signal line, the inductance component of the plate conductor can be canceled by the capacitance component of the dielectric, so the shape of the plate conductor with increased thermal resistance It becomes possible. When the thermal resistance of the plate-like conductor is increased, the heat conduction is deteriorated. As a result, it is possible to suppress the heat of the switching element from being transmitted to the gate drive circuit substrate connected via the signal line.

  Moreover, as a plate-shaped conductor, it is desirable to use the copper thing with favorable heat dissipation. Thus, it becomes possible to exhibit the outstanding heat dissipation effect by using a copper plate-shaped conductor as a signal wire | line.

As the above-mentioned switching element, it is preferable to use a SiC-GTO element. However, as other wide gap semiconductor elements, in addition to silicon carbide (SiC), a wide range such as gallium nitride (GaN) or diamond is used. It is also possible to use a gap semiconductor.
In addition to the structure using a plate conductor for the signal line as described above, if a cooling structure in which a cooling means such as a fan for cooling the plate conductor is arranged in the housing is adopted, the heat dissipation property of the plate conductor can be improved. This can be made even more remarkable.

  In addition, if a cooling structure is formed in which a ventilation path of a fan in which the plate-like conductor is arranged by providing a partition made of a heat insulating material that partitions the accommodation space of the switching element and the gate driving circuit board, It becomes possible to further improve the cooling effect of the conductor.

  Furthermore, when a fan that cools the switching element is disposed in the housing, a temperature sensor is disposed in the vicinity of the switching element, and the rotation of the fan is controlled based on the output of the temperature sensor, The operating temperature of the switching element can be monitored by the temperature sensor, and if the fan is rotationally controlled based on the output of the temperature sensor, the air volume of the fan can be adjusted. Allows constant operation.

  According to the present invention, the signal line for transmitting the drive signal from the gate drive circuit board to the switching element is configured by the plate-like conductor having heat dissipation, which is caused by a steady loss of the switching element or a temperature rise due to the switching loss. The heat of the switching element is quickly dissipated into the surrounding space with a temperature gradient appearing on the signal line between the switching element and the gate drive circuit board. It is possible to prevent malfunction and destruction in advance, protect the signal line and the gate drive circuit board from heat, and provide a highly reliable power conversion device.

  1 and 2 show a power conversion device incorporated in, for example, a large capacity UPS or a battery power storage system. 1 is a plan view showing a main schematic configuration of the apparatus, and FIG. 2 is a side view thereof. In the following embodiments, an inverter device that converts a DC voltage from a DC power source into an AC converter will be described as a power converter. However, the present invention is not limited to this, and the DC conversion from the AC power source and the DC power source are not limited thereto. It can be applied to all power conversions including DC conversion from AC and AC conversion from AC power supply. Furthermore, this invention is applicable not only to a power converter device but other switching devices, such as a power switch.

  This power conversion device includes an inverter device 14 that converts a DC voltage from a DC power source such as a solar cell or a fuel cell into an AC by an on / off operation of a switching element 11 and supplies power to a load. The output frequency command and the voltage command in the inverter device 14 are applied to the switching element 11 by transmitting a drive signal output from the gate drive circuit board 12 to the gate terminal of the switching element 11.

  The inverter device 14 of the embodiment shown in the figure is connected to a switching element 11 composed of a wide gap semiconductor element, and the switching element 11 via a signal line 13, and a gate drive that applies a drive signal to the switching element 11. The circuit board 12 is housed in a housing 15. The one-phase (U-phase) switching element 11 and its gate drive circuit board 12 form a pair to form a one-phase inverter device 14, and the three-phase (U-phase, V-phase, W-phase) The switching element 11 and its gate drive circuit board 12 constitute a three-phase inverter device 14. In this embodiment, a one-phase inverter device 14 composed of a pair of one-phase switching elements 11 and a gate drive circuit board 12 is illustrated.

  In the inverter device 14, for example, a SiC-GTO element is used as the wide gap semiconductor element constituting the switching element 11. As other wide gap semiconductor elements, gallium nitride (GaN), diamond, or the like can be used in addition to silicon carbide (SiC). The gate drive circuit board 12 is mounted with various electronic components for generating a drive signal for the switching element 11.

  Here, since the switching element 11 uses a SiC-GTO element that can operate at a high withstand voltage, a low loss, and a high temperature, the switching element 11 is for element cooling for suppressing a steady loss of the switching element 11 and a temperature increase due to the switching loss. A heat sink and a fan are not required, and the inverter device 14 can be easily reduced in loss and size.

  However, when the switching element 11 composed of the wide gap semiconductor element described above is turned on and off at a high temperature (about 400 ° C.), the heat generated from the switching element 11 is transmitted through the signal line 13 to the gate drive circuit. It is transmitted to the substrate 12.

  Therefore, the signal line 13 for transmitting a drive signal from the gate drive circuit board 12 to the switching element 11 is formed of a flat plate conductor made of copper, for example, having heat dissipation. Since this signal line 13 is made of copper, it has excellent heat dissipation, and since it can secure a large heat dissipation area with a wide flat plate shape, it can reduce wiring inductance as a conductor. By using such a flat conductor as the signal line 13, a temperature gradient can be developed between the switching element 11 and the gate drive circuit board 12.

  That is, when the switching element 11 operates, a voltage is generated by the product of the wiring inductance and the current flowing through the signal line. When this wiring inductance is large, the generated voltage becomes large, and it appears as a transient jumping voltage when the switching element 11 is operated, and there is a concern that the performance of the switching element 11 may be degraded or damaged.

  Therefore, by forming the signal line 13 as a wide copper plate, it is equivalent to connecting the inductances in parallel in terms of a circuit, the wiring inductance can be reduced, and the inductance component generated during the switching operation of the switching element 11 As a result, it is possible to suppress the jump of the gate voltage due to the product of the current and the current, and to prevent the switching element 11 from being degraded or damaged.

  Further, if the signal line 13 adopts an overlapping structure including a pair of flat conductors 13a shown in FIG. 3A and a dielectric 13b interposed between the pair of flat conductors 13a, a gate voltage is obtained. Can be further suppressed, and a large heat dissipation effect can be obtained. In other words, when the dielectric 13b is sandwiched between a pair of plate conductors 13a, a distributed constant circuit of an inductance L component and a capacitance C component is formed as shown in FIG. 3B, and the capacitance due to the dielectric 13b. Since the inductance L component of the conductor 13a itself can be canceled by the C component, jumping of the gate voltage can be further suppressed, and a large heat radiation effect can be obtained. As the material for the dielectric 13b described above, a ceramic material such as alumina, mica, polyimide, glass, an aramid material, or the like may be used.

  Thus, by configuring the signal line 13 with a flat copper plate, the heat of the switching element 11 generated due to the steady loss of the switching element 11 or the temperature rise due to the switching loss is quickly dissipated to the surrounding space by the signal line 13. Therefore, it is possible to suppress accumulation in the signal line 13 itself or transmission to the gate drive circuit substrate 12 connected via the signal line 13.

  Note that the signal line 13 can reduce the wiring inductance as the dimension between the switching element 11 and the gate drive circuit board 12 is shorter, so that a large heat radiation effect can be obtained. Further, if the signal line 13 is short, the signal line 13 can be constituted by only one copper plate without using the overlapping structure as shown in FIG.

  Furthermore, as shown in FIG. 4, the signal line 13 can be formed into a shape in which the thermal resistance of the flat conductor 13a is increased, for example, a shape bent in a wavy shape, a constricted shape, a spiral structure, or the like. However, in this case, since the dimension of the signal line 13 becomes long as described above, it may be difficult to reduce the wiring inductance. Therefore, if an overlapping structure of a pair of flat conductors 13a and dielectrics 13b is adopted as the signal line 13, the inductance component of the flat conductors 13a can be canceled by the capacitance component of the dielectrics 13b. Can be easily reduced.

  If the shape of the flat conductor 13a is increased as described above, the heat conduction between the switching element 11 and the gate drive circuit board 12 is deteriorated, and as a result, the heat of the switching element 11 is reduced in its signal. Heat transfer to the gate drive circuit board 12 connected via the line 13 can be suppressed.

  When the drive signal is transmitted from the gate drive circuit board 12 using the signal line 13 described above, the heat dissipation effect is shown in FIG. The switching element temperature in FIG. 5 is the temperature at point P in FIG. 2, and the gate drive circuit substrate temperature is the temperature at point Q in FIG.

  As is apparent from FIG. 5, the gate drive circuit substrate temperature can be reduced to about 80 ° C. with respect to the switching element temperature of about 200 ° C., and the heat radiation effect by the signal line 13 is obtained. Accordingly, it is possible to transmit a drive signal from the gate drive circuit board 12 and to prevent malfunction or destruction of the gate drive circuit board due to heat.

  In addition to the structure using the signal line 13 having the above-described configuration, a fan 17 for cooling the signal line 13 is provided in the housing 15. The fan 17 is attached to a portion corresponding to the signal line 13, and a fan whose size is sufficient to cool the signal line 13 is used. In this case, as shown in FIG. 1, a space 19 for accommodating the switching element 11 and the signal line 13 and a space 23 for accommodating the gate drive circuit board 12 are partitioned by a partition wall 18 made of a heat insulating material. Thus, by providing the partition wall 18 that divides the two spaces 19 and 23, a cooling structure is formed in which the space 19 is formed as a ventilation path for the fan 16. In this way, in addition to the heat dissipation property of the signal line 13, the cooling effect of the conductor 13 by the fan 17 can be exhibited more remarkably.

  When the drive signal is transmitted from the gate drive circuit board 12 by operating the fan 17 using the signal line 13 described above, the effect of adding the cooling effect of the fan 17 to the heat dissipation effect of the signal line 13 is shown in FIG. Shown in The switching element temperature in FIG. 6 is the temperature at point P in FIG. 2, and the gate drive circuit substrate temperature is the temperature at point Q in FIG.

  As apparent from FIG. 6, the gate drive circuit substrate temperature can be reduced to about 40 ° C. with respect to the switching element temperature of about 200 ° C., and the cooling effect of the fan 17 is added to the heat radiation effect of the signal line 13. The effect was obtained. As a result, it is possible to transmit a drive signal from the gate drive circuit board 12, and it is possible to more reliably prevent malfunction or destruction of the gate drive circuit board due to heat.

  Although the case where the fan 17 is used as the cooling means for cooling the signal line 13 has been described, the present invention is not limited to this, and other cooling means include a fin structure, a water cooling structure, a heat pipe structure, It is also possible to adopt a structure using Peltier.

  Further, a fan 16 that cools the switching element 11 is disposed in the housing 15 so that a space 19 that accommodates the switching element 11 and the signal line 13 serves as a ventilation path. The fan 16 is attached to a portion corresponding to the switching element 11, and the size of the fan 16 is sufficient to cool the switching element 11. On the other hand, a temperature sensor (not shown) is disposed in the vicinity of the switching element 11 and the fan 16 is rotationally controlled based on the output of the temperature sensor.

  In this way, the operating temperature of the switching element 11 can be monitored by the temperature sensor, and if the rotation of the fan 16 is controlled based on the output of the temperature sensor, the air volume of the fan 16 can be adjusted and the switching can be performed. The operation temperature of the element 11 can be adjusted to enable operation at a constant high temperature.

  In FIG. 2, a partition wall 25 that partitions the space 23 that houses the gate drive circuit board 12 is provided to form a space 24 that houses the peripheral device 22.

In the embodiment of the power converter according to the present invention, it is a plan configuration diagram showing a structure in which a switching element and a gate drive circuit board are accommodated in a housing. It is a side block diagram of FIG. (A) is sectional drawing which shows the example which made the structure which inserted | pinched the dielectric material between a pair of plate conductors, (b) is a circuit diagram which shows the equivalent circuit in the structure of the signal line of (a). It is sectional drawing which shows the signal wire | line of the shape which enlarged the thermal resistance of the plate-shaped conductor. It is a characteristic view which shows the switching element temperature and gate drive circuit board | substrate temperature by the heat dissipation effect of a conductor. It is a characteristic view which shows the switching element temperature and gate drive circuit board | substrate temperature by the heat dissipation effect of a conductor, and the cooling effect of a fan. It is a circuit diagram which shows an example of the inverter apparatus comprised by the switching element.

Explanation of symbols

11 Switching elements (wide gap semiconductor elements)
12 Gate drive circuit board 13 Signal line (band plate conductor)
14 Inverter device (power converter)
15 Housing 16, 17 Fan 18 Bulkhead 19 Space

Claims (9)

  A switching element composed of a wide gap semiconductor and a gate driving circuit board connected to the switching element and applying a driving signal to the switching element are stored in a housing, and the on / off operation of the switching element is controlled by the driving signal. In the switching device, a signal line for transmitting a drive signal from the gate drive circuit board to the switching element is constituted by a plate-like conductor having heat dissipation.   The switching device according to claim 1, wherein the signal line has a superposed structure including a pair of plate conductors and a dielectric interposed between the pair of plate conductors.   The switching device according to claim 2, wherein the signal line has a shape in which a thermal resistance of the plate-like conductor is increased.   The switching device according to claim 1, wherein the plate-like conductor is made of copper.   The switching device according to any one of claims 1 to 4, wherein the switching element is a SiC-GTO element.   The switching device according to claim 1, wherein cooling means for cooling the plate-like conductor is disposed in the housing.   The switching device according to claim 6, wherein the cooling means is a fan.   The switching device according to claim 7, wherein a ventilation path of a fan in which the plate-like conductor is disposed is formed by providing a partition made of a heat insulating material that partitions the accommodation space of the switching element and the gate drive circuit board.   9. The fan according to claim 6, wherein a fan for cooling the switching element is disposed in the housing, a temperature sensor is disposed in the vicinity of the switching element, and the rotation of the fan is controlled based on an output of the temperature sensor. A switching device according to claim 1.

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