JP2022054164A - Main circuit system for railroad vehicle - Google Patents

Abstract

To provide a main circuit system for a railroad vehicle that can be miniaturized while occurrence of deviation of a heat generation portion is suppressed.SOLUTION: The present disclosure relates to a main circuit system for a railroad vehicle, including: a converter that converts single-phase AC power to output DC power; an inverter that converts the DC power output from the converter to output three-phase AC power; a six-pole electric motor that is driven by the three-phase AC power output from the inverter; and a radiator disposed under the vehicle floor and configured to cool the converter and the inverter by traveling wind. The converter and the inverter are configured such that the maximum energy loss of each phase of the converter and the maximum energy loss of each phase of the inverter are equal when the electric motor is driven.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a main circuit system for railway vehicles.

In a railroad vehicle that collects AC current from an overhead wire and travels, AC power is converted into electric power by a power conversion device (that is, a converter and an inverter) and supplied to an electric motor. In the main circuit system including such a power conversion device and an electric motor, the structure of the electric motor can be changed from 4 poles to 6 poles to reduce the size.

Further, for the purpose of downsizing the main circuit system, there is known a method of cooling a power conversion device by applying a traveling wind of a railroad vehicle to a radiator and omitting a cooling device (that is, a blower) (see Patent Document 1). ).

Japanese Unexamined Patent Publication No. 2007-13223

As described above, when the motor has 6 poles, the amount of heat generated in the power conversion device increases and the bias of the heat generation points increases. If the area of the radiator is increased in order to suppress the occurrence of such bias in the heat generating portion, the above-mentioned object of miniaturization cannot be achieved.

One aspect of the present disclosure is to provide a main circuit system for railway vehicles that can be miniaturized while suppressing the occurrence of bias in heat generation points.

One aspect of the present disclosure is configured to convert a single-phase AC power and output DC power, and to convert the DC power output by the converter to output three-phase AC power. An inverter, a 6-pole electric power configured to be driven by the three-phase AC power output by the inverter, and a radiator configured to cool the converter and the inverter by running wind while being placed under the vehicle floor. , Is a main circuit system for railway vehicles. The converter and the inverter are configured so that the maximum energy loss of each phase of the converter and the maximum energy loss of each phase of the inverter when the motor is driven are equal to each other.

According to such a configuration, the maximum energy loss of each phase of the converter and the maximum energy loss of each phase of the inverter are made equal to each other, so that the bias of the heat generating portion in the power conversion device is reduced. Therefore, it is possible to suppress the occurrence of bias in the heat generating portion in the power conversion device while reducing the size by using the 6-pole motor and the radiator.

In one aspect of the present disclosure, the converter and the inverter may each include a SiC element. With such a configuration, it is possible to promote miniaturization and weight reduction of the main circuit system for railway vehicles.

One aspect of the present disclosure may further comprise a resistor configured to discharge the charge of the capacitor in at least one of the converter and the inverter. The resistor may be attached to the radiator. According to such a configuration, the resistor is cooled by the radiator, so that the resistor cooling device becomes unnecessary. As a result, the miniaturization of the main circuit system can be promoted.

FIG. 1 is a schematic perspective view showing an example of mounting a main circuit system for a railway vehicle according to an embodiment. FIG. 2 is a schematic cross-sectional view taken along the line II-II of FIG. FIG. 3 is a schematic circuit diagram of the main circuit system for railway vehicles of FIG. FIG. 4 is a schematic view showing the structure of the electric motor of FIG. FIG. 5A is a graph showing an example of the relationship between the rotation speed and voltage or current in the motor, and FIG. 5B is a graph showing an example of the relationship between the rotation speed and torque in the motor. 6A, 6B and 6C are schematic views showing energy loss in each phase of the power conversion device, respectively.

Hereinafter, embodiments to which the present disclosure has been applied will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
The railway vehicle main circuit system 1 (hereinafter, also simply referred to as “main circuit system 1”) shown in FIG. 1 drives a railway vehicle 10 by electric power supplied from an overhead wire. The railway vehicle 10 travels at a high speed of, for example, 180 km / h or more.

As shown in FIGS. 2 and 3, the main circuit system 1 includes a power converter 2, an electric motor 3, resistors 4A, 4B, 4C, 4D, an external power supply 5, and a radiator 6.

<Power converter>
The power conversion device 2 is arranged under the floor of the railway vehicle 10 at a central portion in the traveling direction of the railway vehicle 10 (that is, the extending direction of the rails R1 and R2). The railroad vehicle 10 has a converter 2A, an inverter 2B, and a connecting member 2C.

(converter)
The converter 2A is configured to convert the single-phase AC power input from the overhead wire via the pantograph and output the DC power.

The converter 2A of the present embodiment includes a SiC element (that is, a semiconductor layer made of silicon carbide) as a power semiconductor element. Specifically, all the power semiconductor elements of the converter 2A are SiC elements.

As shown in FIG. 3, the converter 2A has a U-phase circuit and a V-phase circuit. The U-phase circuit and the V-phase circuit each have an upper arm (that is, a high potential side arm) and a lower arm (that is, a low potential side arm).

The upper arms of each of the U-phase circuit and the V-phase circuit have two power semiconductor elements. An intermediate potential terminal 2F is connected between the two power semiconductor elements of the upper arm. A diode having a forward direction toward the upper arm is arranged between the upper arm and the intermediate potential terminal 2F.

The lower arms of each of the U-phase circuit and the V-phase circuit have two power semiconductor elements. An intermediate potential terminal 2F is connected between the two power semiconductor elements of the lower arm. A diode having a forward direction toward the intermediate potential terminal 2F is arranged between the lower arm and the intermediate potential terminal 2F.

The high potential side of each of the U-phase circuit and the V-phase circuit is connected to the intermediate potential terminal 2F via a capacitor. The low potential side of each of the U-phase circuit and the V-phase circuit is also connected to the intermediate potential terminal 2F via a capacitor.

The U-phase circuit of the converter 2A is electrically connected to the external power supply 5 via the AC terminal 2D between the upper arm and the lower arm. The V-phase circuit of the converter 2A is also electrically connected to the external power supply 5 via the AC terminal 2E between the upper arm and the lower arm.

The external power supply 5 is an AC power supply including a main transformer that steps down the single-phase AC voltage input from the overhead wire. A single-phase AC voltage is input to the converter 2A via an external power supply 5 connected to the U-phase circuit and the V-phase circuit.

(Inverter)
The inverter 2B is configured to convert the DC power output by the converter 2A and output the three-phase AC power. The inverter 2B of the present embodiment includes a SiC element as a power semiconductor element. Specifically, all the power semiconductor elements of the inverter 2B are SiC elements.

The inverter 2B has a U-phase circuit, a V-phase circuit, and a W-phase circuit. The U-phase circuit, the V-phase circuit, and the W-phase circuit each have an upper arm (that is, a high potential side arm) and a lower arm (that is, a low potential side arm).

The upper arms of each of the U-phase circuit, the V-phase circuit, and the W-phase circuit have two power semiconductor elements. An intermediate potential terminal 2G is connected between the two power semiconductor elements of the upper arm. A diode having a forward direction toward the upper arm is arranged between the upper arm and the intermediate potential terminal 2G.

The lower arms of each of the U-phase circuit, the V-phase circuit, and the W-phase circuit have two power semiconductor elements. An intermediate potential terminal 2G is connected between the two power semiconductor elements of the lower arm. A diode having a forward direction toward the intermediate potential terminal 2G is arranged between the lower arm and the intermediate potential terminal 2G.

The high potential side of each of the U-phase circuit, the V-phase circuit, and the W-phase circuit is connected to the intermediate potential terminal 2G via a capacitor. The low potential side of each of the U-phase circuit, the V-phase circuit, and the W-phase circuit is also connected to the intermediate potential terminal 2G via a capacitor.

The U-phase circuit, V-phase circuit, and W-phase circuit of the inverter 2B are electrically connected to the motor 3 via the AC terminals 2H, 2I, and 2J between the upper arm and the lower arm, respectively.

(Connecting member)
The connecting member 2C electrically connects the converter 2A and the inverter 2B. The connecting member 2C has a first part 21, a second part 22, and a third part 23.

The first part 21 connects the high potential side of the converter 2A and the high potential side of the inverter 2B. The second part 22 connects the intermediate potential terminal 2F of the converter 2A and the intermediate potential terminal 2G of the inverter 2B. The third part 23 connects the low potential side of the converter 2A and the low potential side of the inverter 2B.

<Motor>
The electric motor 3 is a traveling power source of the railway vehicle 10, and rotates the wheels (not shown) of the railway vehicle 10. The electric motor 3 is an induction motor configured to be driven by the three-phase AC power output by the inverter 2B, and has six poles.

As shown in FIG. 4, the motor 3 has six stators 31A-31F and a rotor 32 arranged inside the stator 31A-31F. The six stators 31A-31F are arranged so that poles different from each other are adjacent to each other in the circumferential direction (that is, the rotation direction) of the electric motor 3.

The 6-pole motor can have a smaller radial width of the stator than, for example, a 4-pole motor. Therefore, the motor 3 can reduce the size and weight of the main circuit system 1.

<Resistor>
The first resistor 4A and the second resistor 4B shown in FIG. 3 are configured to always discharge the electric charge of the capacitor in the converter 2A and the inverter 2B.

The first resistor 4A is arranged in a circuit connecting the first part 21 and the second part 22 of the connecting member 2C. That is, the first resistor 4A is connected in parallel with the plurality of upper arms of the converter 2A and the inverter 2B.

The second resistor 4B is arranged in a circuit connecting the third part 23 and the second part 22 of the connecting member 2C. That is, the second resistor 4B is connected in parallel with the plurality of lower arms of the converter 2A and the inverter 2B.

The first resistor 4A and the second resistor 4B are attached to a radiator 6 described later. The first resistor 4A and the second resistor 4B release heat generated by electric discharge by heat exchange with the radiator 6.

The third resistor 4C and the fourth resistor 4D are configured to discharge the electric charge of the capacitor in the converter 2A and the inverter 2B when an abnormality occurs in the power conversion device 2.

The third resistor 4C is connected to a circuit connecting the first part 21 and the second part 22 of the connecting member 2C together with the switching element. The fourth resistor 4D is connected to a circuit connecting the third part 23 and the second part 22 of the connecting member 2C together with the switching element.

<Heat radiator>
The heat radiating body 6 shown in FIG. 1 is arranged under the floor of the railway vehicle 10 and is configured to cool the converter 2A and the inverter 2B by the traveling wind W. The heat radiating body 6 is exposed below the railroad vehicle 10.

The heat radiating body 6 has a first heat radiating unit 6A and a second heat radiating unit 6B. The first heat radiating unit 6A and the second heat radiating unit 6B each have a plurality of fins protruding downward from the bottom wall constituting the floor surface of the railway vehicle 10. The plurality of fins are arranged apart from each other so that the thickness direction is orthogonal to the traveling direction of the railway vehicle 10.

The first heat dissipation unit 6A is in contact with at least a part of the converter 2A (specifically, a power semiconductor element) and mainly cools the converter 2A. The second heat radiating unit 6B is in contact with at least a part (specifically, a power semiconductor element) of the inverter 2B, and mainly cools the inverter 2B. Further, at least one of the first heat radiation unit 6A and the second heat radiation unit 6B is in contact with the first resistor 4A or the second resistor 4B.

The radiator 6 transfers the heat generated by the converter 2A, the inverter 2B, the first resistor 4A and the second resistor 4B to the traveling wind W via the plurality of fins. That is, the heat radiator 6 exchanges heat between the main circuit system 1 and the atmosphere.

<Energy loss>
FIG. 5A is an example showing the relationship between the rotation speed and the output voltage V1 and the output current I1 in the 4-pole motor and the relationship between the rotation speed and the output voltage V2 and the output current I2 in the 6-pole motor. Further, FIG. 5B is an example of torque characteristics in an electric motor.

As shown in FIG. 5A, the 6-pole motor has a larger output current in the low speed range than the 4-pole motor. Therefore, when a 6-pole motor is used, the energy loss in the power conversion device 2 becomes large.

Therefore, in the case of a design in which the loss of the power semiconductor element in the converter 2A shown in FIG. 6A is larger than that of the inverter 2B, or a design in which the loss of the power semiconductor element in the converter 2A shown in FIG. 6B is larger than that of the inverter 2B, the radiator 6 In the cooling using the running wind, the temperature difference between the converter 2A and the inverter 2B becomes large, and the heat generation portion is biased. The number of black squares in each phase of FIGS. 6A, 6B and 6C schematically represents the magnitude of energy loss.

On the other hand, as shown in FIG. 6C, the converter 2A and the inverter 2B have the maximum energy loss of each phase of the converter 2A (that is, the U phase and the V phase) and each phase of the inverter 2B (that is, that is) when the motor 3 is driven. , U phase, V phase and W phase) are configured to be equal to each other, so that the area of the radiator 6 can be suppressed and the occurrence of bias in the heat generating portion can be suppressed.

In the present embodiment, the area where the power semiconductor element and the diode come into contact with the first heat radiating portion 6A of the radiator 6 in each phase of the converter 2A, and the power semiconductor element and the diode in each phase of the inverter 2B are the second of the radiator 6. It is equal to the area in contact with the heat radiating portion 6B.

[1-2. effect]
According to the embodiment described in detail above, the following effects can be obtained.
(1a) By making the maximum energy loss of each phase of the converter 2A equal to the maximum energy loss of each phase of the inverter 2B, the bias of the heat generating portion in the power conversion device 2 becomes small. Therefore, it is possible to suppress the occurrence of bias of the heat generating portion in the power conversion device 2 while reducing the size by the 6-pole electric motor 3 and the radiator body 6.

(1b) Since the converter 2A and the inverter 2B each include a SiC element, it is possible to promote miniaturization and weight reduction of the main circuit system 1.

(1c) Since the first resistor 4A and the second resistor 4B are cooled by the radiator 6, the cooling device for the first resistor 4A and the second resistor 4B becomes unnecessary. As a result, the miniaturization of the main circuit system 1 can be promoted.

[2. Other embodiments]
Although the embodiments of the present disclosure have been described above, it is needless to say that the present disclosure is not limited to the above-described embodiments and can take various forms.

(2a) In the main circuit system 1 for a railway vehicle of the above embodiment, the converter 2A and the inverter 2B do not necessarily have to include a SiC element. The converter 2A and the inverter 2B may be composed of, for example, a Si element.

(2b) In the main circuit system 1 for a railway vehicle of the above embodiment, the first resistor 4A and the second resistor 4B do not necessarily have to be attached to the radiator body 6.
(2c) In the main circuit system 1 for a railway vehicle of the above embodiment, the circuit configuration of the power conversion device 2 (that is, the converter 2A, the inverter 2B, and the connecting member 2C) is an example.

(2d) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of the plurality of components may be integrated into one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or substituted with respect to the other configurations of the above embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

1 ... Main circuit system for railway vehicles, 2 ... Power converter, 2A ... Converter,
2B ... Inverter, 2C ... Connection member, 2D, 2E ... AC terminal,
2F, 2G ... Intermediate potential terminal, 2H, 2I, 2J ... AC terminal, 3 ... Motor,
4A ... 1st resistor, 4B ... 2nd resistor, 4C ... 3rd resistor, 4D ... 4th resistor,
5 ... External power supply, 6 ... Heat dissipation body, 6A ... First heat dissipation part, 6B ... Second heat dissipation part, 10 ... Railway vehicle,
21 ... Part 1, 22 ... Part 2, 23 ... Part 3, 31A-31F ... Stator,
32 ... Rotor.

Claims (3)

A converter configured to convert single-phase AC power and output DC power,
An inverter configured to convert the DC power output by the converter and output three-phase AC power.
A 6-pole motor configured to be driven by the three-phase AC power output by the inverter, and
A radiator that is placed under the floor of the vehicle and is configured to cool the converter and the inverter by the running wind.
Equipped with
The converter and the inverter are main circuit systems for railway vehicles configured so that the maximum energy loss of each phase of the converter and the maximum energy loss of each phase of the inverter when the electric motor is driven are equal to each other. The main circuit system for a railway vehicle according to claim 1.
The converter and the inverter are main circuit systems for railway vehicles, each including a SiC element. The main circuit system for a railway vehicle according to claim 1 or 2.
Further comprising a resistor configured to discharge the charge of the capacitor in at least one of the converter and the inverter.
The resistor is a main circuit system for a railway vehicle attached to the radiator.

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