JP7451386B2 - power converter - Google Patents

Description

The present invention relates to a power conversion device, and is particularly suitable as a power conversion device for railway vehicles.

A power conversion device installed in a railway vehicle is for controlling an electric motor that drives the vehicle, and is installed under the floor of the vehicle. In addition to the power conversion device, it is necessary to mount many other components such as an air conditioning power source under the floor of a vehicle, so the power conversion device is required to be downsized.

One of the main components of a power converter is a power unit that mainly includes a semiconductor element, a cooler for cooling the semiconductor element, and a filter capacitor for stabilizing the power input from the railway overhead wire. In order to downsize the power converter, it is necessary to downsize the cooler, which is a component of the power unit, while maintaining its cooling performance.

A cooler consists of a heat block that serves as a heat receiving section (for the heat loss of the element), a heat dissipation fin that serves as a heat dissipation section (to the surrounding air), and in some cases, a heat pipe that thermally connects the heat block and the heat dissipation fin. Ru.

There are various types of cooling methods, such as a forced air cooling method using a cooling blower, a water cooling method using a water cooling unit, and a traveling air cooling method that uses the wind generated as the vehicle runs. There is a cooling method. However, due to the limited space available for underfloor equipment, there is a strong demand for downsizing, and in recent years, wind-cooling systems have become mainstream in order to reduce environmental impact and save energy.

Since the running air cooling type cooler needs to cool the heat received by the heat block using only the running air obtained according to the running speed of the railway vehicle, it improves the cooling efficiency and improves the reliability of the entire power converter. We must improve our sexuality. To increase cooling efficiency, there are methods such as increasing the area of the heat dissipation fins, but when multiple semiconductor elements with different heat loss are placed in a heat block, it is necessary to consider the difference in heat loss when arranging the semiconductor elements. This method is effective.

Patent Document 1 discloses a three-level power unit in which a plurality of semiconductor elements with different heat loss are arranged, in which a group of semiconductor elements with small heat loss is arranged in a concentrated manner in the center of a heat block, and cooling air is provided at both ends of the power unit. By arranging semiconductor element groups with large heat loss along the flow direction, the waste heat of the semiconductor element group with large heat loss placed on the windward side can be used to generate the semiconductor element group with large heat generation loss placed on the leeward side. The cooling efficiency is increased by reducing the impact on the air.

JP2006-340490A

In a power conversion device in which a plurality of semiconductor elements having different heat generation losses are arranged in the same heat block, the method of arranging semiconductor elements described in Patent Document 1 can improve cooling efficiency as described above. On the other hand, since the semiconductor element group with large heat loss is placed on the outside of the heat block in the advancing direction, in order to obtain a sufficient cooling effect, the area exceeding the external position of the semiconductor element group with large heat loss heat dissipation fins are required.

In particular, in a power conversion device that uses a traveling wind cooling method and has two or more power units installed one behind the other in the direction of travel of the railway vehicle (hereinafter referred to as the "direction of travel"), the power units are placed at the rear of the direction of travel. In order to ensure the cooling effect of the running wind of the cooler, it is necessary to provide a certain distance between the front and rear heat dissipation fins in the traveling direction of the power unit. Therefore, it is difficult to reduce the size of the power conversion device by shortening the distance between mounting the power unit including the heat dissipation fins.

In the present invention, in a power conversion device that uses a traveling wind cooling method and has two or more power units arranged in front and behind each other in the traveling direction, in which a plurality of semiconductor elements having different heat generation losses are arranged in the same heat block, a cooler is used. The objective is to downsize the power converter in the forward direction while maintaining its cooling performance.

In order to solve the above problems, one of the typical power conversion devices of the present invention includes a plurality of semiconductor element groups, a cooler for cooling the plurality of semiconductor element groups, and a filter capacitor for smoothing the power supply. A power conversion device installed in a railway vehicle, which is a power conversion device that is arranged on one side of a heat block constituting a cooler, and opposite to the position of the heat dissipation fins of the cooler arranged on one side of the heat block. A first semiconductor element group consisting of a motor control power switching element with large heat loss in the center, and a semiconductor element group with heat loss on at least one side of the first semiconductor element group on both sides of the first semiconductor element group in the traveling direction of the railway vehicle. A second semiconductor element group composed of power switching elements used in a small overvoltage protection circuit is arranged , and the width in the advancing direction occupied by the radiation fin is the sum of the first and second semiconductor element groups. This configuration is smaller than the width of the range in the advancing direction.

According to the present invention, it is possible to provide a downsized power conversion device while maintaining the cooling performance of the cooler.
Problems, configurations, and effects other than those described above will be made clear by the description in the following detailed description.

1 is an overall configuration diagram showing a mounting position of a power conversion device according to an embodiment of the present invention on a railway vehicle; FIG. 1 is a front configuration diagram of a power unit according to an embodiment of the present invention. FIG. 7 is a diagram illustrating an example of the arrangement of a semiconductor element group with a large heat generation loss and a semiconductor element group with a small heat generation loss to a heat block in an embodiment. FIG. 3 is a diagram of the heat receiving side and the heat dissipating side of the heat block as seen from the direction of travel in the example. It is a figure which shows the example of installation of the power unit to the power converter under the floor of a railway vehicle in an Example. FIG. 7 is a diagram illustrating an arrangement example of a semiconductor element group with a large heat loss and a semiconductor element group with a small heat loss to a heat block in a conventional form. FIG. 3 is a diagram of a heat receiving side and a heat dissipating side of a heat block in a conventional form as seen from the direction of travel. It is a figure which shows the example of installation of the power unit in the power converter device under the floor of a railway vehicle in a conventional form.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples will be described below as modes for carrying out the present invention with reference to the drawings. Note that the present invention is not limited to this example. In addition, in the description of the drawings, the same parts are denoted by the same reference numerals.

FIG. 1 is an overall configuration diagram showing the mounting position of a power conversion device 100 according to an embodiment of the present invention on a railway vehicle 200.
A power conversion device 100 including a power unit 1 is arranged under the floor of a railway vehicle 200.

The power conversion device 100 is a device that generates direct current from single-phase alternating current and a device that generates three-phase alternating current from direct current. The former is called a converter, and the latter is called an inverter.

FIG. 2 is a front configuration diagram of the power unit 1 according to the embodiment of the present invention (the left and right sides of the figure are in the direction of the sleepers).
The power unit 1 constituting the power conversion device 100 includes a filter capacitor 2, a main circuit wiring 3, a gate wiring 4, a gate control circuit 5, a semiconductor element group 6 with large heat loss, a semiconductor element group 7 with small heat loss, and a cooler 8. It consists of

The power unit 1 includes a semiconductor element group 6 with a large heat loss and a semiconductor element group 7 with a small heat loss, and is controlled by communication. During communication control, a separately provided control device (not shown) outputs control signals to the semiconductor elements constituting the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss, and sends control signals to the power unit 1. The above semiconductor element group (6, 7) is driven via the attached gate control circuit 5 and gate wiring 4.

The filter capacitor 2 is for smoothing the DC power supply, and electrically connects the semiconductor element group 6 with a large heat loss and the semiconductor element group 7 with a small heat loss through the main circuit wiring 3.

As described above, the main circuit wiring 3 is a main circuit wiring that electrically connects the filter capacitor 2, the semiconductor element group 6 with large heat loss, and the semiconductor element group 7 with low heat loss. Generally, the main circuit wiring 3 is a flat laminate bus bar in which the surface of the conductor bar is coated with an insulating film.

The laminate busbar is designed to have low inductance in order to suppress abnormal voltage (surge voltage) that occurs during high-speed switching in an electric circuit using semiconductor element group 6 with large heat loss and semiconductor element group 7 with small heat loss. A positive busbar and a negative busbar are mounted adjacent to each other. Note that instead of the laminated bus bar, a laminated bus bar that is not covered with a laminate material may be used.

The gate wiring 4 is a control circuit wiring for outputting a gate signal generated and output from the gate control circuit 5 to a semiconductor element group 6 with a large heat loss and a semiconductor element group 7 with a small heat loss.

As described above, the gate control circuit 5 is a circuit that generates and outputs a gate signal.

The semiconductor elements used in the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss are, for example, IGBTs (Insulated Gate Bipolar Transistors).

IGBTs have the advantage of low on-resistance, low drive current, and high switching speed. On the other hand, since IGBTs consume a large amount of power and generate heat when energized and cut off, they are generally provided with a cooler.

In addition, the above-mentioned semiconductor elements include a 1-in-1 element module configured with only one arm, a 1-phase 2-in-1 element module that configures a series circuit with two sets of upper and lower arm semiconductors, or a 2-in-1 element module configured with three phases. A 6-in-1 element module may be used in which the elements are combined into a single module.

Here, the semiconductor element group 6 with large heat loss is constituted by, for example, a power switching element for controlling a motor.

An overvoltage protection circuit (not shown) is turned ON when overvoltage of the filter capacitor 2 is detected or when the control power supply is turned off, and is provided for the purpose of discharging the charge accumulated in the filter capacitor 2. This overvoltage protection circuit is classified as the semiconductor element group 7 with low heat loss, and uses, for example, a power switching element for overvoltage protection.

Semiconductor elements (power switching elements) used in overvoltage protection circuits have low switching frequency, and therefore have low heat loss. Therefore, the semiconductor element used in the semiconductor element group 7 with a small heat loss may be the same semiconductor element as the semiconductor element used in the semiconductor element group 6 with a large heat loss.

As described above, the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss can be connected to the filter capacitor 2 by the same laminated busbar or laminated busbar. In that case, a low inductance circuit can be shared, and circuit design can be omitted and reliability can be improved.

The cooler 8 includes a heat block 81, radiation fins 82, and a heat pipe 83. The heat block 81 absorbs heat generated from the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss, and vaporizes and cools the refrigerant sealed in the heat pipe 83. The radiation fins 82 expose the vaporized refrigerant to cooling air to exchange heat, thereby liquefying the refrigerant again.

Particularly, in a running wind cooling system that uses running wind as cooling air, a protective cover is attached to the cooler 8 for the purpose of reducing concerns about damage from flying objects and for the purpose of rectifying the cooling air. Note that the cooler 8 does not necessarily have to include the heat pipe 83 that thermally connects the heat block 81 and the radiation fins 82.

Next, using FIGS. 3 to 5, we will explain the arrangement of the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss in the embodiment of the present invention, and the arrangement of the cooler 8 for cooling these semiconductor element groups. The structure and installation of the power unit 1 will be explained.

In addition, for comparison, the case of a conventional form will also be described. In this case, the same parts are given the same reference numerals, but the conventional forms are distinguished by adding an A after the same numbers.

FIG. 3 is a diagram showing an example of the arrangement of the semiconductor element group 6 with large heat generation loss and the semiconductor element group 7 with small heat generation loss to the heat block 81 in the embodiment.
The semiconductor element group 6 with large heat loss is arranged in a concentrated manner in the center of the heat block 81, and the semiconductor element group 6 is placed on both sides of the semiconductor element group 6 in the direction of movement of the railway vehicle 200 (hereinafter abbreviated as the "direction of movement"). A semiconductor element group 7 with low heat loss is arranged on at least one side (FIG. 3 shows an example in which they are arranged on both sides).

By arranging it in this way, the width (length) in the advancing direction of the radiation fins 82 (framed by broken lines in FIG. 3) can be adjusted closer to the semiconductor element group 6 with large heat loss while maintaining the cooling effect of the cooler 8. It can be made smaller (shorter) than the width (length) in the advancing direction of the arrangement range including the semiconductor element group 7 with low heat generation loss. In terms of area, the area occupied by the radiation fins 82 (broken line frame shown in FIG. 3) is smaller (narrower) than the area of the arrangement range including the semiconductor element group 6 with large heat loss and the semiconductor element group 7 with small heat loss. )can do.

Therefore, the radiation fins 82 can reduce the amount of the cooling air that enters and leaks to the outside, so that a sufficient cooling effect can be obtained even on the leeward side, and the cooling efficiency of the cooler 8 can be increased.

Note that the effects obtained with the power unit 1 alone are the same regardless of whether it is a running air cooling method or a blower forced air cooling method. If so, cooling efficiency can be increased.

On the other hand, FIG. 6 is a diagram showing an example of the arrangement of a semiconductor element group 6 with a large heat loss to the heat block 81 and a semiconductor element group 7 with a small heat loss in a conventional configuration.
This embodiment of the present invention is characterized in that the semiconductor element group 7 with a small heat loss is arranged in a concentrated manner in the center of the heat block 81, and the semiconductor element group 6 with a large heat loss is arranged around it in the direction of movement. It is different from.

In addition, in order to obtain a sufficient cooling effect, unlike the embodiments of the present invention, it is necessary to reduce the size of the heat dissipation fin 82A (framed by broken lines in FIG. 6) in the traveling direction from the external position of the arranged semiconductor element group. Can not.

FIG. 4 is a diagram of the heat receiving side and the heat dissipating side of the heat block 81 viewed from the traveling direction in the example.
Generally, when a sufficient cooling effect cannot be obtained, the number of heat radiation fins 82 is increased in the direction of the sleepers to increase the heat radiation area. However, since the radiation fins 82 in the embodiment can obtain a sufficient cooling effect as described above, the number of the radiation fins 82 can be reduced within the range where a sufficient cooling effect can be obtained. On the other hand, it becomes possible to reduce the size and weight.

On the other hand, FIG. 7 is a diagram of the heat receiving side and the heat dissipating side of the heat block 81 viewed from the traveling direction in the conventional form.
The heat radiation fins 82A provided on the heat radiation side of the heat block 81 have larger dimensions in the direction of movement, resulting in increased pressure loss. Therefore, in order to obtain a sufficient cooling effect, the number of radiating fins 82A is generally increased in the direction of the sleepers, and the power converter 100A cannot be made smaller and lighter in the direction of the sleepers. . This point differs from the embodiment of the present invention. Furthermore, as the heat dissipation fins 82A described above become larger in the direction of the railroad ties, the heat pipes 83A also become larger in the same direction.

FIG. 5 is a diagram illustrating an example of installing the power unit 1 to the power conversion device 100 under the floor of the railway vehicle 200 in the embodiment.
As described above, the two power units 1 installed in the power converter 100 one behind the other in the traveling direction are provided with a certain distance between the heat dissipation fins 82 of the two power units 1 so as to obtain a sufficient cooling effect due to the running wind. It will be installed so that D can be secured.

In the embodiment, since the radiation fins 82 can be made smaller in the traveling direction, the distance L1 between the two power units 1 can be shortened while maintaining the distance D. That is, the advancing direction dimension L2 of the power conversion device 100 can be reduced. Note that the power units 1 are not limited to the installation mode shown in FIG. 5, and two or more power units 1 may be installed one behind the other in the traveling direction.

On the other hand, FIG. 8 is a diagram showing an example of installation of the power unit 1A in the underfloor power conversion device 100A of the railway vehicle 200 in a conventional form.
In the power unit 1A equipped with the radiation fins 82A, it is not possible to shorten the mounting distance L1A (>L1) between the two power units 1A while maintaining the distance D, and it is not possible to reduce the traveling direction dimension L2A of the power converter 100A. This point differs from the embodiment of the present invention.

Moreover, the arrangement direction of the semiconductor elements used in the semiconductor element group 6 with large heat generation loss and the semiconductor element group 7 with small heat generation loss in the embodiment of the present invention is not mentioned here. Therefore, regarding the arrangement of the semiconductor element, for example, the long side direction of its outer shape may be parallel to or perpendicular to the direction of movement, and the direction does not matter.

Similarly, regarding the types of semiconductor elements used, a plurality of types of semiconductor elements having different structures may be arranged.

Furthermore, instead of the semiconductor element group 7 with low heat loss, a heat generating element such as a resistor that requires cooling by the cooler 8 may be installed.

By the way, the configuration according to the embodiment of the present invention described above shows an example of the content of the present invention, and it is also possible to combine other known techniques without departing from the gist of the present invention. Various changes are possible within the scope, including omission of part of the configuration.

1...Power unit, 2...Filter capacitor, 3...Main circuit wiring, 4...Gate wiring,
5...Gate control circuit, 6...Semiconductor element group with large heat loss,
7...Semiconductor element group with small heat loss, 8...Cooler, 81...Heat block,
82...Radiation fin, 83...Heat pipe, 100...Power converter, 200...Railway vehicle

Claims (4)

A power conversion device installed in a railway vehicle, comprising a plurality of semiconductor element groups, a cooler for cooling the plurality of semiconductor element groups, and a filter capacitor for power supply smoothing,
A power switch for controlling a motor with large heat loss is provided in the center of the opposite side of the heat block, opposite to the position of the radiation fins of the heat block arranged on one side of the heat block constituting the cooler. A first semiconductor element group constituted by a semiconductor element , and a power switching element used in an overvoltage protection circuit with small heat loss on at least one side of the first semiconductor element group on both sides of the first semiconductor element group in the traveling direction of the railway vehicle. a second semiconductor element group consisting of
A power conversion device characterized in that a width in the traveling direction occupied by the heat radiation fin is smaller than a width in the traveling direction of a total arrangement range of the first and second semiconductor element groups. The power conversion device according to claim 1,
The power conversion device is characterized in that the first and second semiconductor element groups are connected to the filter capacitor by the same laminated busbar or laminated busbar. The power conversion device according to claim 1 or 2,
A heating element made of a resistor is placed in place of the second semiconductor element group in place of the second semiconductor element group.
A power conversion device characterized by: A railway vehicle on which a plurality of power conversion devices according to claim 1 are mounted side by side in the traveling direction .

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