Patent Description:
A power conversion device used to control a motor for driving a vehicle such as an electric railroad vehicle is installed under the floor of the vehicle. However, it is necessary to mount many parts such as, for example, a power supply for air conditioning, in addition to the power conversion device, under the floor of the vehicle, and thus the power conversion device is required to be downsized.

On the other hand, in order to improve efficiency and to respond to installation environments, various circuits as shown below exist, and downsizing of each circuit has been attempted.

In a technique disclosed in Patent Literature <NUM>, in order to reduce a loss caused by winding resistance by reducing a motor current while boosting a voltage applied to the motor, when a boosting circuit is provided in a power conversion device for a railroad vehicle, the size of equipment is prevented from increasing due to the boosting circuit.

In a technique disclosed in Patent Literature <NUM>, even in the case where a capacitor voltage is raised due to a contact loss of a pantograph and a sudden change in load when a regenerative brake is applied, reliability can be improved by installing an overvoltage suppression circuit to prevent an overvoltage to a semiconductor element in a power conversion device.

In a technique disclosed in Patent Literature <NUM>, a reactor and a brake resistor necessary for a brake chopper device that reduces wear of an air brake to obtain brake force by converting electric power generated by a motor into heat by the brake resistor are shared with other devices to realize downsizing by reducing the number of parts of necessary devices and to reduce a failure risk. Patent Literature <NUM> relates to a power converter assembly for high-performance applications, especially for a drive motor of a rail-bound vehicle. Patent Literature <NUM> relates to a converter power unit that comprises: a heat sink; n power switch modules on the heat sink; a first group of laminated bus bars comprising a first and a second bus bar; a capacitor group comprising m capacitors; a second group of laminated bus bars comprising a third and a fourth bus bar, the first bus bar is connected with the third bus bar, the second bus bar is connected with the fourth bus bar. Patent Literature <NUM> relates to a power converter that includes a plurality of semiconductor modules, a heat receiving block, a cooling fin, a filter capacitor, and a gate drive device.

Although the power conversion device is optimized to suit each purpose in the technique disclosed in each of Patent Literatures <NUM> to <NUM>, it is difficult to realize downsizing by reducing the number of parts as an entire system and to improve reliability on a route where these circuits are mixed.

In view of the above-described problems, it is provided a power conversion device having the features defined in claim <NUM>. Further, it is provided an electric railroad vehicle having the features defined in claim <NUM>.

According to the present invention, a four-phase integrated power conversion device can be configured in such a manner that one phase is used for any one of a boosting circuit, an overvoltage suppression circuit, and a brake chopper circuit for a specific purpose and is combined with three phases configuring an inverter. Alternatively, in the case of an AC overhead contact line, a four-phase integrated power conversion device can be configured as a two-phase two-group converter.

As described above, all the circuits are integrated into four phases, or a combination of four-phase integrated power conversion devices is mounted, so that the number of individual necessary parts can be reduced, and the productivity of the power conversion device can be improved. In addition, downsizing by reducing the number of parts and a reduction in failure risk can be realized.

Hereinafter, first and second embodiments of a power conversion device according to the present invention will be described with reference to the drawings.

<FIG> is a diagram for showing a structure of a power conversion device <NUM> according to the first embodiment of the present invention by using a perspective view.

The power conversion device <NUM> is configured using cooling equipment <NUM>, plural power modules <NUM>, plural capacitors <NUM>, a positive-electrode bus bar <NUM>, a negative-electrode bus bar <NUM>, and bus bars <NUM> to <NUM> for outputting or inputting or for specific purposes. The plural power modules (<NUM>-in-<NUM> power modules) <NUM> are installed while coming into contact with the cooling equipment <NUM>, and four <NUM>-in-<NUM> power modules <NUM> are arranged on the cooling equipment <NUM> while aligning a module short-length direction <NUM> with the vertical direction (see also <FIG>). In addition, the plural capacitors <NUM> are disposed on the opposite side of the cooling equipment <NUM> across the power modules <NUM>.

Here, a structure of a single <NUM>-in-<NUM> power module <NUM> is shown in <FIG>. The <NUM>-in-<NUM> power module <NUM> has a substantially cuboidal shape, and a module positive-electrode terminal 6a, a module negative-electrode terminal 6b, and a terminal 6c for inputting or outputting module AC or for a specific purpose are provided on the short-side sides along a module longitudinal direction <NUM>. In addition, a control signal line (not shown) can be extracted from space between the module positive-electrode terminal 6a and the terminal 6c for inputting or outputting module AC or for a specific purpose.

<FIG> shows a front view in a state where only the capacitors <NUM> are dismounted from the structure of the power conversion device <NUM> shown in <FIG>. As shown in the drawing, the positive-electrode bus bar <NUM> is connected to each module positive-electrode terminal 6a of each power module <NUM> (<NUM> to <NUM>), and the negative-electrode bus bar <NUM> is connected to each module negative-electrode terminal 6b of each power module <NUM> (<NUM> to <NUM>). In addition, the positive-electrode bus bars <NUM> and the negative-electrode bus bars <NUM> are located at both ends of the power conversion device <NUM> in the horizontal direction in a state where the dismounted capacitors <NUM> are sandwiched in the vertical direction, and are arranged in a plate shape in the vertical direction. Further, the bus bars <NUM> to <NUM> (<NUM> to <NUM>) for outputting or inputting or for specific purposes extend upward in the vertical direction along each terminal 6c for inputting or outputting module AC or for a specific purpose (see <FIG>) of each power module <NUM> (<NUM> to <NUM>) located in the central part, and are connected to terminals <NUM> to <NUM> (<NUM> to <NUM>) for outputting or inputting or for specific purposes shown in <FIG>.

<FIG> shows a front view in a state where the bus bars are dismounted from the structure shown in <FIG>. The power module <NUM> shown in <FIG> is installed while coming into contact with the cooling equipment <NUM> in the arrangement of the array shown in <FIG>. Namely, in order to realize high-density packaging, the power modules are configured as a four-line configuration (power modules <NUM> to <NUM>) by allowing the module short-length direction <NUM> to coincide with the vertical direction (gravity direction), and are configured as a two-line configuration mirror symmetric with respect to the central axis (the alternate long and two short dashes line shown in <FIG>) of the cooling equipment <NUM> by allowing the module longitudinal direction <NUM> to coincide with the travelling direction (the alternate long and short dash line with arrows shown in <FIG> and <FIG>) of the train.

As described above, the length of the power conversion device <NUM> in the travelling direction can be shortened by employing the above-described configuration, and the pressure loss of the cooling equipment <NUM> that performs cooling using travelling wind can be advantageously reduced. In addition, a control signal line (not shown) can be extracted from space between the module positive-electrode terminal 6a and the terminal 6c for inputting or outputting module AC or for a specific purpose in the direction of the arrow dashed lines shown in <FIG>.

The power conversion device <NUM> is configured using, for example, a <NUM>-in-<NUM> power module <NUM> (<NUM>) in which a U-phase upper and lower arms series circuit is mounted, a <NUM>-in-<NUM> power module <NUM> (<NUM>) in which a V-phase upper and lower arms series circuit is mounted, a <NUM>-in-<NUM> power module <NUM> (<NUM>) in which a W-phase upper and lower arms series circuit is mounted, and a power module <NUM> (<NUM>) for a specific purpose to boost the contact line voltage. Hereinafter, the <NUM>-in-<NUM> power modules <NUM>, <NUM>, <NUM>, and <NUM> of the respective phases will be simply referred to as power modules <NUM> when they are not especially distinguished from each other.

As shown in, for example, <FIG>, each power module <NUM> has a half-bridge configuration in which an upper arm-side current switch circuit configured using a parallel connection circuit of an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (metal-oxide-semiconductor field-effect transistor) as semiconductor elements and a diode and a lower arm-side current switch circuit configured using the same parallel connection circuit are arranged in series.

Next, a four-phase integrated power conversion device to which specific functions can be added can be configured by applying and mounting the power conversion device <NUM> according to the first embodiment to an electric railroad vehicle <NUM>. A concrete configuration example thereof will be described with reference to <FIG>. First, common constitutional elements will be described.

The power conversion device <NUM> functions as an inverter in <FIG>, and functions as a converter in <FIG>. In the case of the inverter shown in <FIG>, a DC voltage applied between an overhead contact line <NUM> and a grounding part <NUM> is supplied to the power conversion device <NUM>. For example, the DC voltage passing through a reactor <NUM> is input to a three-phase inverter configured using the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the first phase, the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the second phase, and the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the third phase through the <NUM>-in-<NUM> power module <NUM> (<NUM>) and a capacitor <NUM> for a specific purpose. An AC voltage converted by the three-phase inverter is output from an output terminal <NUM> (<NUM>), an output terminal <NUM> (<NUM>), and an output terminal <NUM> (<NUM>) that are connected to the terminal 6c for inputting or outputting module AC or for a specific purpose of each power module, and drives a motor <NUM>.

In addition, in the case of the converter (power conversion device 100a) shown in <FIG>, an AC input voltage applied between the overhead contact line <NUM> and the grounding part <NUM> is supplied to a converter configured using the respective <NUM>-in-<NUM> power modules <NUM> to <NUM> (<NUM> to <NUM>) of the first to fourth phases through a first group-side transformer <NUM> and a second group-side transformer <NUM>, and is converted to a DC voltage. The DC voltage converted by the converter is supplied to a power conversion device 100b configuring an inverter through the capacitor <NUM>.

Next, individual configurations will be described.

<FIG> is a diagram for showing a circuit configuration of a four-phase integrated power conversion device to realize a boosting circuit. In addition, destinations to which terminals for outputting or for specific purposes are connected in the circuit configuration are shown in the following Table <NUM>.

The <NUM>-in-<NUM> power module <NUM> (<NUM>) of the first phase, the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the second phase, and the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the third phase serve as power modules corresponding to the U phase, V phase, and W phase, and the output terminals <NUM> to <NUM> (<NUM> to <NUM>) connected to a module AC terminal 6c of each power module are connected to the U phase, V phase, and W phase of the motor <NUM>, respectively.

In addition, the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the fourth phase is connected to the DC side of the inverter for the boosting circuit as a specific purpose, and a terminal <NUM> (<NUM>) for a specific purpose of the power module is connected to the reactor <NUM>.

Namely, as shown in Table <NUM> (a column indicated as "<FIG>"), regarding the terminal 6c for inputting or outputting module AC or for a specific purpose of each of the power modules <NUM> to <NUM>, the first phase is connected to a U-phase motor wire of the output of the inverter as an output terminal, the second phase is connected to a V-phase motor wire of the output of the inverter as an output terminal, the third phase is connected to a W-phase motor wire of the output of the inverter as an output terminal, and the fourth phase is connected to a boosting wire of the inverter as a terminal for a specific purpose.

<FIG> is a diagram for showing a circuit configuration of a four-phase integrated power conversion device to realize an overvoltage suppression circuit. In addition, destinations to which terminals for outputting or for specific purposes are connected in the circuit configuration are shown in the following Table <NUM>.

Since the <NUM>-in-<NUM> power modules <NUM> to <NUM> (<NUM> to <NUM>) of the first to third phases configure a three-phase inverter, the connection modes are the same as those shown in <FIG>, and the fourth phase is different as a specific purpose. The <NUM>-in-<NUM> power module <NUM> (<NUM>) of the fourth phase is connected to the DC side of the inverter for overvoltage suppression as a specific purpose, and the terminal <NUM> (<NUM>) for a specific purpose of the power module <NUM> (<NUM>) is connected to the reactor <NUM> through a resistor <NUM>.

Namely, as shown in Table <NUM> (a column indicated as "<FIG>"), regarding the terminal 6c for inputting or outputting module AC or for a specific purpose of each of the power modules <NUM> to <NUM>, the first phase is connected to the U-phase motor wire of the output of the inverter as an output terminal, the second phase is connected to the V-phase motor wire of the output of the inverter as an output terminal, the third phase is connected to the W-phase motor wire of the output of the inverter as an output terminal, and the fourth phase is connected to an inverter overvoltage suppression circuit wire on the DC side of the inverter as a terminal for a specific purpose.

<FIG> is a diagram for showing a circuit configuration of a four-phase integrated power conversion device to realize a brake chopper circuit. In addition, destinations to which terminals for outputting or for specific purposes are connected in the circuit configuration are shown in the following Table <NUM>.

Since the <NUM>-in-<NUM> power modules <NUM> to <NUM> (<NUM> to <NUM>) of the first to third phases configure a three-phase inverter, the connection modes are the same as those shown in <FIG> and <FIG>, and the fourth phase is different as a specific purpose. The <NUM>-in-<NUM> power module <NUM> (<NUM>) of the fourth phase is connected to the DC side of the inverter for a brake chopper as a specific purpose, and the terminal <NUM> (<NUM>) for a specific purpose of the power module <NUM> (<NUM>) is connected to the grounding part <NUM> through the resistor <NUM>.

Namely, as shown in Table <NUM> (a column indicated as "<FIG>"), regarding the terminal 6c for inputting or outputting module AC or for a specific purpose of each of the power modules <NUM> to <NUM>, the first phase is connected to the U-phase motor wire of the output of the inverter as an output terminal, the second phase is connected to the V-phase motor wire of the output of the inverter as an output terminal, the third phase is connected to the W-phase motor wire of the output of the inverter as an output terminal, and the fourth phase is connected to a brake chopper wire on the DC side of the inverter as a terminal for a specific purpose.

<FIG> is a diagram for showing a circuit configuration of a four-phase integrated power conversion device to realize a two-group two-phase converter circuit. In addition, destinations to which input terminals are connected in the circuit configuration are shown in the following Table <NUM>.

In the configuration shown in <FIG>, the four-phase integrated power conversion device is applied for inputting AC of a two-group two-phase converter. Thus, the terminal 6c for inputting or outputting module AC or for a specific purpose of each of the power modules <NUM> to <NUM> is used as an input terminal in this case. Hereinafter, "'" is added only when the terminal 6c is used as an input terminal.

In the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the first phase and the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the second phase, input terminals <NUM>' and <NUM>' (<NUM>' and <NUM>') are connected to the first group-side transformer <NUM>. In addition, in the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the third phase and the <NUM>-in-<NUM> power module <NUM> (<NUM>) of the fourth phase, input terminals <NUM>' and <NUM>' (<NUM>' and <NUM>') are connected to the second group-side transformer <NUM>. Accordingly, the two-group two-phase converter circuit is configured using the four <NUM>-in-<NUM> power modules <NUM> to <NUM> (<NUM> to <NUM>).

Namely, as shown in Table <NUM> (a column indicated as "<FIG>"), regarding the terminal 6c for inputting or outputting module AC or for a specific purpose of each of the power modules <NUM> to <NUM>, the first phase is connected to a first group U-phase wire of the converter as an input terminal, the second phase is connected to a first group V-phase wire of the converter as an input terminal, the third phase is connected to a second group U-phase wire of the converter as an input terminal, and the fourth phase is connected to a second group V-phase wire of the converter as an input terminal.

In addition, the four-phase integrated power conversion device can be configured to have a set of an inverter and a converter including various functions by being applied to the inverter side and the converter side. This example is shown in <FIG>.

<FIG> is a diagram for showing an example of an electric railroad vehicle having a configuration in which an inverter 100b including the brake chopper circuit shown in <FIG> and a two-group two-phase converter 100a shown in <FIG> are combined with each other. It is obvious that the combination is not limited to the example shown in <FIG>, and a combination of an inverter 100b including the boosting circuit shown in <FIG> and the two-group two-phase converter 100a shown in <FIG> or a combination of an inverter 100b including the overvoltage suppression circuit shown in <FIG> and the two-group two-phase converter 100a shown in <FIG> can be employed.

Namely, according to the present invention, any combinations of the above-described circuits have the same hardware configuration as a power conversion device to be used. Therefore, it is possible to realize a reduction in the number of parts for adjusting interfaces between the circuits and to improve the productivity of the power conversion device, leading to downsizing of the device and improvement of reliability as a result.

As the structure of the first embodiment shown in <FIG>, the bus bars for outputting or inputting or for specific purposes and the connection parts of the terminals 6c for inputting or outputting module AC or for specific purposes of the power module <NUM> are integrated in the central part of the power conversion device <NUM>, and the capacitors <NUM> are distributed from side to side. In the structure of the first embodiment, the positive-electrode bus bar <NUM> and the negative-electrode bus bar <NUM> do not interfere with the central part of the power module <NUM>, and thus there is an effect that a control signal line extracted from a control terminal (not shown) located in the middle of the module (a control signal line is lead to the direction indicated by the dashed arrows in <FIG> and <FIG>) is hardly affected by a magnetic field generated from the positive-electrode bus bar <NUM> and the negative-electrode bus bar <NUM>. On the other hand, when the capacitors <NUM> are separated into two, there is a possibility that necessary electrostatic capacitance cannot be sufficiently secured.

A second embodiment of the present invention to be described next has a structure to solve the point.

A structure of a power conversion device <NUM> according to the second embodiment is shown in <FIG>. <FIG> is a diagram for showing a structure of the power conversion device <NUM> according to the second embodiment by using a perspective view. <FIG> shows a front view in a state where only the capacitor <NUM> is dismounted from the structure of the power conversion device <NUM> shown in <FIG>, and <FIG> shows a front view in a state where the bus bars are dismounted from the structure shown in <FIG>.

In the second embodiment, a single capacitor <NUM> is provided as shown in <FIG>. Therefore, as shown in <FIG>, an arrangement relation in which the entire power module <NUM> is aligned is the same as the case of the first embodiment shown in <FIG>. However, the individual power modules <NUM> to <NUM> are arranged upside down, which is opposite to the case of the first embodiment, so that the terminals 6c for inputting or outputting module AC or for specific purposes are located at both ends of the power conversion device <NUM> (accordingly, the module positive-electrode terminals 6a and the module negative-electrode terminals 6b are located in the central part of the power conversion device <NUM>). It should be noted that a control signal line (not shown) can be extracted from space between the module positive-electrode terminal 6a and the terminal 6c for inputting or outputting module AC or for a specific purpose in the direction of the arrow dashed lines shown in <FIG> as similar to the first embodiment. In addition, by arranging the module positive-electrode terminals 6a and the module negative-electrode terminals 6b as shown in <FIG>, the positive-electrode bus bar <NUM> and the negative-electrode bus bar <NUM> are arranged on either end side of the power conversion device <NUM> in a plate shape in the vertical direction as shown in <FIG>.

Claim 1:
A power conversion device comprising a capacitor (<NUM>), a positive-electrode bus bar (<NUM>), a negative-electrode bus bar (<NUM>), bus bars (<NUM>, <NUM>, <NUM>, <NUM>) that are each configured to be connected to an AC-phase terminal of for instance a motor wire, a specific purpose bus bar (<NUM>, <NUM>, <NUM>, <NUM>), and semiconductor modules (<NUM>; <NUM>, <NUM>, <NUM>, <NUM>), each semiconductor module (<NUM>) having a half-bridge configuration in which two semiconductor elements are arranged in series,
wherein the capacitor (<NUM>) and each semiconductor module (<NUM>) have a cuboidal shape, and wherein positive-electrode terminal modules (6a), negative-electrode terminal modules (6b), and terminal modules (6c) for inputting or outputting AC or for a specific purpose are mounted on one side of each semiconductor module (<NUM>),
wherein each terminal module (6a, 6b, 6c) has a cuboidal shape, the semiconductor modules (<NUM>) are mounted side-by-side on a cooling equipment (<NUM>) such that for each semiconductor module (<NUM>) the module side opposite to its side on which the terminal modules (6a, 6b, 6c) are mounted is in contact with the cooling equipment (<NUM>), and such that the positive-electrode terminal modules (6a) are lined up along first lines, the negative-electrode terminal modules (6b) are lined up along second lines, and
the terminal modules (6c) for inputting or outputting AC or for a specific purpose are lined up along third lines, wherein the first lines,
the second lines, and the third lines are parallel lines,
wherein the positive-electrode bus bar (<NUM>) is connected to each positive-electrode terminal (6a) of each semiconductor module (<NUM>), the negative-electrode bus bar (<NUM>) is connected to each negative-electrode terminal (6b) of each semiconductor module (<NUM>), and wherein the bus bars (<NUM>, <NUM>, <NUM>, <NUM>) that are each configured to be connected to an AC_phase terminal, and the specific purpose bus bar (<NUM>, <NUM>, <NUM>, <NUM>) extend in the same direction along each terminal module (6c) for inputting or outputting AC or for a specific purpose, and
wherein the positive-electrode bus bar (<NUM>) has an L-shape and
overlays the positive-electrode terminal modules (6a), the negative electrode bus bar (<NUM>) has an L-shape and overlays the negative-electrode terminal modules (6b), and the capacitor (<NUM>) is disposed on the concave side of an L-shaped bus bar (<NUM>; <NUM>).