JP3481887B2 - Power module - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced air cooling type power module.

[0002]

2. Description of the Related Art A power module is composed of a large number of semiconductor elements, has good maintainability, and can be made compact in size. Therefore, an example of applying a cooling structure by forced air cooling is increasing. Since the device is required to be small in size, high in performance, and cheaper in price, various types of semiconductor elements to be used are applied depending on price, function, outer shape, application circuit, and the like.

The semiconductor element includes a high-speed switching element that generates a relatively large amount of heat as compared with its outer shape, a relatively small diode, and a thyristor. Therefore, in order to mount these devices in a high density by combining them, it is an important design theme to eliminate the imbalance of the heat generation amount of the semiconductor elements and to efficiently cool them. However,
Satisfying this theme is becoming more difficult due to the significant increase in heat density accompanying the miniaturization, high speed, and large capacity of high-speed switching elements.

FIG. 11 shows an example of a concrete circuit which constitutes such a power module.

In this circuit, a diode element L5 forming a rectifier L1 for converting an AC voltage at an AC input point L0 into a DC voltage, a rectifier L1 converting a DC power into an AC power, and a smoothing capacitor L4 are sandwiched in parallel. A high-speed switching element L6 that constitutes the connected inverter circuit L2,
The smoothing capacitor L4 includes a thyristor element L7 that opens and closes a bypass circuit L3 having a resistor L8 for protecting the circuit from an inrush current when it is not charged.

Two high-speed switching elements L6 are connected in parallel in the inverter circuit L2 in order to obtain the required output power and to use the high-speed switching element L6 at the maximum operating temperature or less. That is, this is because the current per one high-speed switching element L6 is reduced to reduce the amount of heat generation and the heat density.

12 and 13 are diagrams showing an example of a power unit forming the circuit shown in FIG. A flat plate K9 for mounting a semiconductor element and a radiation fin K for radiating the heat energy generated by the semiconductor to the outside air
In the semiconductor cooling fin K8 made of a metal having good thermal conductivity, the thyristor element L7 and the diode element L5 are arranged on the upstream side of the cooling air K7.
On the other hand, the high speed switching element L6 is arranged on the downstream side.

A circuit shown in FIG. 15 shows an inverter circuit in the case where the high-speed switching element L6 in the circuit shown in FIG. 11 has a large capacity.
The circuit is the same as the circuit shown in FIG. 11 except that the number of parallel lines is reduced.

FIG. 16 is a diagram showing an example of a cooling structure of a semiconductor element which constitutes the circuit shown in FIG. In this figure, a semiconductor element cooler K13 has a hollow portion having a flat plate shape and a predetermined thickness filled with a coolant liquid K16 for boiling cooling, and a semiconductor element L11 provided on the flat plate surface is Through an evaporation part K11 that transfers the generated heat energy to the refrigerant liquid and a hollow part that is attached to the end of the evaporation part K11 and is continuous with the evaporation part K11, through a refrigerant gas K17 by boiling of the refrigerant liquid K16. And a condenser K12 having fins K14 for transmitting the heat energy of the evaporator and releasing the heat energy to the cooling air K7. This semiconductor element cooler K
In the evaporation unit K11 of 13, the thyristor element L7 and the diode element L5 are arranged on the left side when viewed from the upstream side of the cooling air K7, and the high speed switching element L6 is arranged on the right side with respect to the cooling air K7. Further, a thyristor element L7, a diode element L5, and a high-speed switching element L6 are similarly arranged on the back side of the cooler K13.

[0010]

Problems to be Solved by the Invention FIGS. 11, 12, and 1
The conventional power unit shown in FIG. 3 has the following problems.

The semiconductor element cooling fin K8 is versatile and inexpensive, but is limited in cooling heat density due to fin efficiency because it is made of only metal having good thermal conductivity. Therefore, it is not possible to cope with the increase in heat density due to the miniaturization and large capacity of the semiconductor element. In order to expand the device capacity, a semiconductor element having a heat density that the cooling fins can tolerate is used, and the device capacity is increased by increasing the parallel number. Further, in order to reduce the heat density, it is necessary to widen the distance between the semiconductor elements as needed.

Further, the cooling fins have a limit to the diffusion of heat inside the cooling fins due to the fin efficiency, and the influence of heat in the series direction on the cooling air is large.

In order to avoid the influence of upstream heat, FIG.
As shown in FIG. 5, a method of shifting the center line of heat generation is used, but this is not preferable in consideration of downsizing of the device because the cooling fin becomes large. Further, the diode element L5 and the thyristor element L7 have different heat densities. In this example, since the heat density of the thyristor element L7 is higher than that of the diode element L5,
As shown in FIG. 2, the influence of heat on the high-speed switching element L6a arranged downstream of the thyristor element L7 is such that the high-speed switching element L6 arranged downstream of the diode element L5.
Greater than b. As a result, the cooling fins must be selected at the maximum temperature point of L6b, and the cooling fins become large. However, there is a cooling capacity larger than necessary at locations other than L6b, which is inefficient.

Among the above-mentioned problems, the power unit shown in FIGS. 15 and 16 to 19 corresponds to the high heat density due to the small size and large capacity of the semiconductor element. Cooler K13
JP-A-8-204075 discloses a thermosyphon-type cooling system that has a hollow portion filled with a coolant liquid for boiling cooling and transports the heat generated by a semiconductor element by boiling and condensing the coolant. It is a cooler having a structure.

This cooler has low heat resistance inside the cooler and good fin efficiency. Further, even if there is a large imbalance in the amount of heat generated in the semiconductor element L11 attached to the evaporator, the degree of soaking is large, and therefore, FIG.
1. It can be applied to a semiconductor device having a large thermal resistance as compared with the cooling fins shown in FIGS. However, the pressure vessel structure and the enclosed refrigerant are relatively expensive.

Diode element L5, thyristor element L7
For example, the mounting area is increased to mount the device, but the thickness of the condenser K12 is almost determined by the heat density of the high-speed switching element L6 having a high heat density, so that the inner volume is expanded, and the amount of refrigerant is larger than necessary. It increases and becomes expensive.

Further, since the width of the cooling air K7 is increased in the direction parallel to the cooling air K7, the opening area of the condenser K12 is increased and the amount of cooling air is increased. Therefore, in order to increase the cooling air volume, it is necessary to increase the size of the ventilation fan corresponding to the opening area of the condensing unit, which is contrary to downsizing and cost reduction of the device, and also causes problems such as loud noise. is there.

The present invention has been made in order to solve the above-mentioned problems, and provides a small-sized power module capable of reducing the unit cost of capacitance, in which a high heat density semiconductor element and a low heat density semiconductor element are mounted at high density. With the goal.

[0019]

The first feature of the present invention is to:
The refrigerant liquid is filled inside, and the heat energy of the evaporator is transferred via the vaporization part that transfers the heat energy generated by the switching element provided on the flat plate surface to the coolant liquid, and the vapor due to the boiling of the coolant liquid. A cooling fin having a condenser having a fin for discharging heat energy to the outside air; a flat plate for mounting a semiconductor element; and a fin for discharging the heat energy generated by the semiconductor element to the outside air. That is, the cooling fin and the cooler are arranged in series with respect to the cooling air path, and the exhaust side of the cooling fin and the intake side of the condenser are connected.

Therefore, the heat imbalance on the upstream side is eliminated, which contributes to downsizing of the shape of the cooler. Further, since the heat source can be connected in series to the cooling air, the area of the intake port can be reduced and the ventilation fan can be downsized. Further, it is possible to improve the cooling efficiency of a device in which a high-speed switching element having a high heat density and a semiconductor element having a low heat density coexist due to the reduction in size and the increase in capacity to reduce the size and reduce the unit cost of capacitance.

The second feature of the present invention is that the exhaust side of the cooling fin is connected to a part of the intake side of the condenser.

Therefore, the shapes of the cooling fins and the condenser of the cooler have little interdependence, and by optimizing the outer shape, the outer shape of the apparatus can be made small and the cost can be reduced.

A third feature of the present invention is to provide a wind tunnel for connecting the exhaust side of the cooling fins with the intake side of the condenser, and to attach or remove all or any of the cooling fins, the cooler, and the wind tunnel. Is. Therefore, the cooling fins or the coolers can be divided and the maintenance and inspection can be performed individually, and the maintainability is improved.

A fourth feature of the present invention is that the wind tunnel for guiding cooling air from the intake port of the power unit to the intake side of the condenser is provided, and the wind tunnel covers the cooling fins. Therefore, the cooling capacity of the cooling fins can be optimized to reduce the cost of the device and provide a power unit with excellent maintainability.

A fifth feature of the present invention is that a plurality of semiconductor elements are attached to cooling fins and arranged in a wind tunnel, and the cooling air passing through the wind tunnel also cools the surface of the semiconductor element.
Therefore, the surface of the semiconductor element provided on the cooling fin can be cooled. In addition, the device mounting density can be increased by accommodating the semiconductor element provided in the cooling fin in the wind tunnel.

A sixth feature of the present invention is that a semiconductor element constituting a rectifying circuit for converting AC power into DC is arranged on the flat plate of the cooling fin, and an inverter for converting DC into AC is arranged on the plate of the evaporation section. This is to arrange a switching element that constitutes a circuit and electrically connect a rectifier circuit and an inverter circuit. Therefore, it is possible to reduce the size and performance of a power unit that houses a power conversion circuit including a converter and an inverter in the same module.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 show a first embodiment of the present invention, and are mounting diagrams showing mounting in the circuit configuration shown in FIG.

An outer shell of the power module K3 is composed of a box-shaped unit chassis K19, and an AC input point L0 and an input fuse L are provided in front of the unit chassis K19.
9, an output terminal L10 is provided. Further, inside the power module K3, a semiconductor cooling fin K8, a cooler K13, and a smoothing capacitor L4 are provided.

The semiconductor cooling fin K8 made of a metal having good thermal conductivity, which has a flat plate K9 for mounting a semiconductor element and a heat radiation fin K10 for radiating the heat energy generated by the semiconductor to the outside air, is exposed to the cooling air K7. A thyristor element L7 and a diode element L5 are arranged in parallel.

In the cooling air K7, a cooler K13 having the same internal structure as the cooler described with reference to FIGS. 17 to 19 is arranged on the downstream side of the semiconductor cooling fin K8. The evaporator K11 of the cooler K13 is provided with a high heat density high-speed switching element L6.

The exhaust side of the cooling fin K8 is connected to the intake side of the condenser K12 of the cooler K13.

Although not shown in the figure, electric wires for wiring the electric parts so as to form the circuit shown in FIG.
Conductors are also arranged.

The cooling air K7 sucked from the opening provided on the front surface of the unit chassis K19 passes through the semiconductor element cooling fins K8 and the cooler K13, and is discharged from the exhaust port on the rear surface.

Since the inside of the cooler K13 is a small-capacity pressure vessel and the refrigerant gas is in a saturated state, there is a correlation between the internal pressure and the gas temperature, and the condenser section K1.
When heat is locally applied to 2 from the outside, it acts to equalize the local internal pressure difference due to the temperature difference. That is, the refrigerant gas circulates so as to average the internal temperature.

Therefore, even if a heat imbalance occurs in the upstream cooling fin K8 and a temperature difference occurs at the intake point of the cooler K13, it is averaged by the refrigerant gas, and the evaporation section K1.
The effect on the high-speed switching element L6 attached to No. 1 is the average value of the amount of heat generated by the cooling fin K8. There is a first-order correlation between the cooling air flow rate, the heat generation amount, and the temperature increase value, and the gas temperature rise inside the cooler due to the upstream cooling fin K8 is due to the cooling air flow rate passing through the condenser K12 and the upstream cooling fin K8. It will be determined only by the calorific value, and will not be affected by the partial heat imbalance.

According to the power module of this embodiment, the heat source can be connected in series to the cooling air, so that the area of the intake port can be reduced and the ventilation fan can be downsized. Further, it contributes to the downsizing of the shape of the cooler by eliminating the heat imbalance on the upstream side. Further, the cooling efficiency of a device in which a high-speed switching element having a high heat density and a semiconductor element having a low heat density coexist due to a small size and a large capacity is improved to reduce the size, reduce the unit price of the capacity, and reduce the noise.

FIGS. 3 and 4 show a second embodiment of the present invention and are mounting diagrams showing mounting of the circuit shown in FIG. This embodiment differs from the embodiments shown in FIGS. 1 and 2 in that the exhaust area of the cooling fin K8 and the intake area of the condenser K11 of the cooler K13 are changed, and the diode element L5 and the thyristor element are changed. The present invention can also be applied to the case where the outer shape of the cooling fin K8 determined by the heat generation amount of L7 on the exhaust side and the outer shape of the intake part of the cooler K13 determined by the heat generation amount of the high-speed switching element L6 cannot be the same.

According to the power module of this embodiment, the shapes of the cooling fins and the condenser of the cooler have little interdependence, and the optimum outer shape allows the outer shape of the device to be small and the cost to be reduced. .

FIGS. 5 and 6 show a third embodiment of the present invention, and are mounting diagrams showing the mounting of the circuit shown in FIG. In this embodiment, in the embodiment shown in FIG. 1, the cooling fin K8 and the condenser K12 of the cooler K13 are connected via a wind tunnel K18. The semiconductor cooling fin K8 is fixed to a fixed panel K21a provided above the semiconductor cooling fin K8.
The fixed panel K21a has a width wider than that of the semiconductor cooling fin K8, and the protruding ear portion has a unit chassis K1.
It is placed on the upper part of 9 and fastened with screws or the like. Further, the cooler K13 is similarly fixed by the cooler fixing panel K21b.

A handle K is attached to the fixed panels K21a and K21b.
Twenty is attached. The wind tunnel K18 is fixed to the unit chassis K19.

Fixed panel K2 for fixing cooling fin K8
The cooling fin K8 can be removed by removing the screw that fastens the unit chassis K19 to the unit 1a and pulling the handle K20 upward, and the cooler K13 can be similarly removed.

According to the power module of this embodiment, the correlation between the gas temperature inside the cooler K13, the amount of cooling air passing through the condenser K12, and the amount of heat generation of the upstream cooling fin K8 is maintained, and the cooling fin is maintained. K8 or cooler K1
It is possible to perform maintenance and inspection separately by dividing 3 and to improve maintainability.

FIGS. 7 and 8 show a fourth embodiment of the present invention and are mounting diagrams showing mounting of the circuit shown in FIG. In this embodiment, in the embodiment shown in FIGS. 5 and 6, the wind tunnel is extended from the inlet of the condenser K12 to the opening in front of the unit chassis K19. The flat plate K9 of the cooling fin K8 constitutes a part of the floor of the wind tunnel K118, and the heat radiation fin K10 is formed so as to project from the flat plate K9 toward the inside of the wind tunnel. At the top of the wind tunnel K118, a fixed panel K21
a and a handle K20 are provided, and the fixed panel K21a is fastened to the unit chassis K19 with screws or the like. If the screw that fastens the fixed panel K21a to the unit chassis K19 is removed and the handle K20 is pulled up, the wind tunnel K118
At the same time, the cooling fin K8 is removed.

According to the power module of the present embodiment, the gas temperature inside the cooler K13, the amount of cooling air passing through the condenser K12, and the heat generation amount of the upstream cooling fin K8 are maintained and the cooling fin (EN) Provided is a power unit which has an optimal cooling capacity, which can reduce the cost of the device and which is excellent in maintainability.

FIGS. 9 and 10 show a fourth embodiment of the present invention and are mounting diagrams showing the mounting of the circuit shown in FIG. In this embodiment, among the embodiments shown in FIGS. 7 and 8, the diode element L5 and the thyristor element L7 are provided inside the wind tunnel K118 extending from the inlet of the condenser K12 to the opening in front of the unit chassis K19. The cooling fin K8 is arranged.

Both side surfaces of the wind tunnel K118 are constituted by part of the unit chassis K19. A hole larger than the planar shape including at least the cooling fin K8, the diode element L5, and the thyristor element L7 is bored in the upper part of the wind tunnel K118. A fixed panel K21a is provided on the upper portion of the cooling fin K8, and the fixed panel K21a is fastened to the unit chassis at the end with screws or the like. Fixed panel K21a
When the screw fastening the unit to the unit chassis K19 is removed and the handle K20 is pulled upward, the cooling fin K8 is removed.

According to the power module of the present embodiment, the surface of the semiconductor element mounted on the cooling fin K8 can be cooled, and the semiconductor element provided on the cooling fin K8 can be housed in the wind tunnel. The device mounting density can be improved.

[0049]

According to the present invention, in a power module for power conversion using a plurality of semiconductor elements having different heat densities, it is possible to eliminate the heat imbalance and realize the miniaturization of the cooler shape. it can.

[Brief description of drawings]

FIG. 1 is a schematic plane mounting view showing a mounted state of a power module according to a first embodiment of the present invention.

FIG. 2 is a schematic side sectional mounting view showing a mounted state of the power module shown in FIG.

FIG. 3 is a schematic front mounting view showing a mounting state of cooling fins and a cooler portion of the power module according to the second embodiment of the present invention.

FIG. 4 is a schematic side mounting view showing a mounting state of a cooling fin and a cooler portion shown in FIG.

FIG. 5 is a schematic plan view showing a mounting state of the power module according to the third embodiment of the present invention.

6 is a schematic side sectional mounting view showing a mounted state of the power module shown in FIG.

FIG. 7 is a schematic plan view showing a mounting state of the power module according to the fourth embodiment of the present invention.

8 is a schematic side sectional mounting view showing a mounted state of the power module shown in FIG. 7. FIG.

FIG. 9 is a schematic plan mounting view showing a mounting state of a power module according to a fifth embodiment of the present invention.

FIG. 10 is a schematic side sectional mounting view showing a mounted state of the power module shown in FIG.

FIG. 11 is a circuit diagram showing an example of a specific circuit of the power module.

FIG. 12 is a schematic plan view showing a mounting example of a conventional power module forming the circuit shown in FIG.

13 is a schematic side sectional mounting view of the power module shown in FIG.

14 is a schematic plan mounting view showing a state in which the arrangement of high-speed switching elements is changed in the power module shown in FIG.

FIG. 15 is a circuit diagram showing an example of another specific circuit of the power module.

16 is a schematic side sectional mounting view showing a mounting example of a conventional power module that constitutes the circuit shown in FIG.

FIG. 17 is a front sectional view showing the inside of the cooler shown in FIG.

FIG. 18 is a front mounting view showing the cooler shown in FIG. 16.

FIG. 19 is a side surface mounting view showing the cooler shown in FIG. 16;

[Explanation of symbols]

K3 power module K8 cooling fin K9 flat plate K10 heat dissipation fin K11 Evaporator K12 condensing part K13 cooler K18 wind tunnel K118 wind tunnel L5 diode element L6 switching element L7 thyristor element

Claims (6)

(57) [Claims] 1. An evaporating section which is filled with a refrigerant liquid and which transfers thermal energy generated by a switching element provided on a flat plate surface to the refrigerant liquid, and the evaporating section through vapor generated by boiling of the refrigerant liquid. The heat energy of the semiconductor element is transmitted to the outside air and a condenser having a fin having a fin for releasing the heat energy to the outside air, a flat plate to which the semiconductor element is attached, and the heat energy generated by the semiconductor element is emitted to the outside air. A cooling fin having a fin, the cooling fin and the cooler are arranged in series with respect to a cooling air path, and an exhaust side of the cooling fin and an intake side of the condenser are connected to each other. A power module characterized in that. 2. The power module according to claim 1, wherein the exhaust side of the cooling fin is connected to a part of the intake side of the condenser. 3. A wind tunnel that connects the exhaust side of the cooling fin and the intake side of the condenser is provided, and all or any of the cooling fin, the cooler, and the wind tunnel are detachably configured. The power module according to claim 1. 4. A wind tunnel for guiding cooling air from an intake port of the power unit to an intake side of the condenser section,
The power module according to claim 1, wherein the wind tunnel covers the cooling fins. 5. The semiconductor device according to claim 4, wherein a plurality of semiconductor elements are attached to the cooling fin and arranged in the wind tunnel, and cooling air passing through the wind tunnel also cools the surface of the semiconductor element. Power module. 6. A semiconductor element forming a rectifying circuit for converting AC power into DC is arranged on the flat plate of the cooling fin, and an inverter circuit for converting DC into AC is formed on the flat plate of the evaporation section. 6. The power module according to claim 1, further comprising a switching element arranged to electrically connect the rectifier circuit and the inverter circuit.