Noise current leakage prevention structure, noise current leakage prevention method, and electric railway vehicle

Abstract

To provide a noise current leakage prevention structure, a noise current leakage prevention method, and an electric railway vehicle that are capable of suppressing noise leakage caused by the switching operation of a power conversion device.SOLUTION: A noise current leakage prevention structure comprises: a three-phase output line 17 that transmits power between a power conversion device 16 electrically connected to a vehicle body 20 side and a main motor 18 electrically connected to a rail 21 side; a shield 25 that is applied to the three-phase output line 17; and connection lines 31a, 31b that are electrically connected to the shield 25 and connect the vehicle body 20 side and the rail 21 side via a capacitor 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a noise current leakage prevention structure, a noise current leakage prevention method, and an electric railway vehicle.

Background Art

[0002] For example, in an electric railway vehicle, in addition to electromagnetic noise generated by a power converter in a substation and electromagnetic noise generated by an inverter for driving the railway vehicle, electromagnetic noise generated due to disconnection from an overhead wire of a pantograph, noise caused by the contact and separation of wheels from a rail, etc., various noises may be superimposed. In such an electric railway, as one of the problematic noise factors, there is noise generated due to the switching operation of a power conversion device. When the power conversion device drives an electric motor by flowing a drive current through the electric motor, a parasitic capacitance exists between the winding part of the electric motor and the motor frame which is the metal housing of the electric motor, and thus high-frequency noise current leaks through this parasitic capacitance. In addition, in recent years, new semiconductor materials such as SiC (silicon carbide) have been adopted for power devices in order to miniaturize and reduce losses of the power conversion device. As a result, the power conversion device can perform a faster and higher-frequency switching operation, while satisfying miniaturization and low losses, the high-frequency noise current generated by the switching operation has come to have harmonic components up to a higher frequency, and has come to affect devices that handle high-frequency signals such as in the MHz band. As a method for suppressing such noise propagation, in addition to the application of countermeasure components such as a magnetic core and a shielding material, countermeasures by shipbuilding such as wiring inside the vehicle are used.

[0003] Patent Document 1 discloses a circuit configuration of an electric vehicle. In this circuit configuration, the main conversion device converts single-phase AC power supplied from an overhead wire into three-phase AC power and drives the main electric motor. The earth wire is connected to the wheel via a grounding brush and is also connected to the case of the electric motor. The grounding resistor is connected between the earth wire and the vehicle body. The neutral point grounding part of the main conversion device and the grounding resistor are connected to the vehicle body at a common connection point. Patent Document 2 discloses a railway vehicle. The railway vehicle comprises an electric motor arranged on a bogie to rotate and drive the wheels, a main converter that converts power supplied from an overhead line into three-phase AC power to drive the electric motor, a three-phase power line connecting the electric motor and the main converter and transmitting the three-phase AC power, a vehicle body which is a conductor that continuously covers at least the space between the electric motor and the main converter, and a wire support structure that supports the three-phase power line so as to be close to the vehicle body, wherein the vehicle has a grounding conductor that electrically connects the main converter and the vehicle body, and a return conductor that electrically connects the frame of the electric motor and the vehicle body in the region where the flexibility of the three-phase power line is required, and the return conductor is arranged to be close to and along the three-phase power line. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2011-166968 [Patent Document 2] Japanese Patent Publication No. 2021-36742 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, conventional systems cannot sufficiently reduce the impedance of the return path, nor can they suppress electromagnetic coupling to the wiring running parallel to the motor, thus failing to achieve sufficient noise suppression. The present invention aims to provide a noise current leakage prevention structure, a noise current leakage prevention method, and an electric railway vehicle that can suppress the leakage of noise current generated from a power conversion device. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides a noise current leakage prevention structure comprising: a power transmission line that transmits power between a power conversion device electrically connected to the vehicle body and an electric motor electrically connected to the rails; a shield applied to the power transmission line; and a connecting line that is electrically connected to the shield and also connects the vehicle body and the rails via a capacitor.

[0007] Here, the shield is divided into a vehicle side and a rail side, and the connecting wires can be electrically connected to each of the divided shields via a capacitor. In this case, noise current can be passed through while electrically insulating the vehicle side from the rail side. Furthermore, the power transmission lines can be electrically connected to the vehicle body and the rails via a relay connector, and the connecting wires can be electrically connected to each of the divided shields via a capacitor placed in the relay connector. In this case, the capacitor can be placed using the relay connector. Furthermore, one end of the shield can be electrically connected to the vehicle body, while the other end of the shield is connected to the rail via a capacitor and connecting wires. In this case, the capacitor can be placed using equipment that is electrically connected to the rail. Furthermore, the capacitor can be mounted on the motor frame, and the other end of the shield and the motor (which is on the rail side) can be connected via the capacitor using connecting wires. In this case, the capacitor can be mounted using the motor frame. Furthermore, the capacitor is positioned on the bogie frame, and the other end of the shield and the bogie frame (which is on the rail side) can be connected via the capacitor using connecting wires. In this case, the capacitor can be positioned using the bogie frame. Furthermore, in addition to electrically connecting to the shield, at least one of the vehicle body side and the rail side, and the vehicle bodies themselves, can be further connected via a dielectric. In this case, the potential difference between the vehicle body and the shield can be suppressed. Furthermore, the dielectric material can be arranged on a terminal block. In this case, the dielectric material can be arranged using the terminal block. Furthermore, the dielectric material is provided on each of the multiple terminal blocks and can be connected to the vehicle body. In this case, the potential difference between the vehicle body and the shield can be further suppressed. Furthermore, the shield can serve as a return path for leakage currents generated due to parasitic capacitance in the motor. In this case, the electromagnetic coupling between the transmission line and the shield can be strengthened, and the shield can also be protected from the effects of external noise.

[0008] Furthermore, the present invention is a noise current leakage prevention structure comprising: a power transmission line that transmits power between a power conversion device electrically connected to the vehicle body and an electric motor electrically connected to the rails; a shield applied to the power transmission line; and a connecting line that is electrically connected to the shield and also connects at least one of the vehicle body side and the rails side, and the vehicle bodies side to each other, via a dielectric.

[0009] Furthermore, the present invention is a noise current leakage prevention method that prevents noise current leakage when transmitting power between a shielded power converter electrically connected to the vehicle body and an electric motor electrically connected to the rails, by electrically connecting to the shield and connecting the vehicle body and the rails via a capacitor.

[0010] Furthermore, the present invention relates to an electric railway vehicle comprising: a metal body; a power conversion device electrically connected to the body and converting the supplied power into alternating current power; an electric motor electrically connected to the rails and rotating the wheels with the converted alternating current power; a power transmission line that transmits power between the power conversion device and the electric motor; a shield applied to the power transmission line; and a connecting line electrically connected to the shield and also connecting the body and the rails via a capacitor. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a noise current leakage prevention structure, a noise current leakage prevention method, and an electric railway vehicle that can suppress the leakage of noise current generated from a power conversion device. [Brief explanation of the drawing]

[0012] [Figure 1] It is a schematic diagram showing an example of a vehicle (electric railway vehicle) to which the present invention is applicable. [Figure 2] It is a configuration diagram of Embodiment 1 showing a drive circuit for a vehicle to which the present invention is applicable, and shows an example of the configuration around a power conversion device mounted on a railway vehicle. [Figure 3] It is a diagram showing the circuit configuration under the vehicle floor of the railway vehicle of Embodiment 1. [Figure 4] It is a diagram showing the circuit configuration diagram of the vehicle in Embodiment 2. [Figure 5] It is a diagram showing the circuit configuration diagram of the vehicle in Embodiment 3. [Figure 6] (a) to (c) are diagrams showing the effects of Embodiment 1 to Embodiment 3.

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In all the drawings for explaining the embodiments, the same parts are generally denoted by the same reference numerals, and the repeated explanations thereof are omitted.

[0014] <Overall description of the vehicle> FIG. 1 is a schematic diagram showing an example of a vehicle (electric railway vehicle) to which the present invention is applicable. In FIG. 1, two vehicles, a left driving vehicle 1 and a right leading vehicle 2, are shown. Although FIG. 1 shows only two vehicles for the sake of explanation, it is possible to connect more vehicles. Note that the left - right direction in FIG. 1 is the front - rear direction of the vehicle.

[0015] Each vehicle includes a car body 20 composed of a metal structure or the like so as to cover the passenger compartment. The car body 20 is supported by two bogies 50 at the front and rear that include bogie frames 40 and wheels 19, and the wheels 19 roll on the rail 21. Further, on the upper part of the driving vehicle 1, a pantograph 12 is provided and is configured to be able to contact the overhead wire 11.

[0016] <Explanation of the drive circuit for vehicles> Next, we will describe the vehicle drive circuits for driving the above-mentioned drive vehicle 1 and lead vehicle 2. Here, the vehicle drive circuits will be described using Examples 1 to 3. <Example 1> Figure 2 is a diagram of the configuration of Embodiment 1, which shows a vehicle drive circuit to which the present invention can be applied, and illustrates an example of the configuration around a power converter mounted on a railway vehicle. The configuration in Figure 2 is mainly a configuration that can be installed in the drive vehicle 1 of Figure 1. Figure 3 is a diagram showing the circuit configuration under the vehicle floor of the railway vehicle of Embodiment 1.

[0017] As shown in Figure 2, power is supplied from the substation via overhead lines 11, pantograph 12, and VCB (Vacuum Circuit Breaker). The current is supplied to the primary side of the transformer 14 via a circuit breaker (vacuum circuit breaker) 13. One end of the primary winding of the transformer 14 is connected to the overhead line 11 via a pantograph 12, and the other end is connected to the grounded rail 21 via the wheels 19 from the vehicle grounding wire 22. A grounding resistor 23 is connected between the vehicle and the vehicle, and a return current flows from this vehicle grounding wire 22 to the rail 21 via the wheel axle.

[0018] The power supplied from the overhead line 11 is input to the primary winding of the transformer 14 via the pantograph 12, and the power generated in the secondary winding of the transformer 14 is input to the power converter 16. The power generated in the tertiary winding of the transformer 14 is input to auxiliary equipment 24 such as ventilation and air conditioning systems. The power converter 16 converts the supplied power into alternating current power. The power converter 16 consists of a converter and an inverter. The converter converts the input alternating current voltage into a desired direct current voltage. The inverter converts the direct current voltage converted by the converter into an alternating current voltage of any voltage and frequency, and outputs it to the main motor 18 via a three-phase output line 17, which is an example of a power transmission line. The main motor 18 is an example of an electric motor, and it rotates the wheels 19 using converted AC power.

[0019] As shown in Figure 3, the frame of the main motor 18 is fixed to the bogie frame 40 of the bogie that supports the car body 20, and as shown in Figure 1, two bogies 50 are arranged in one vehicle. The car body 20 is made of metal, and a grounding resistor 23 is connected between the vehicle grounding wire 22 and the car body 20. This prevents rail current from being drawn up to the car body 20 and concentrate on a specific grounding brush 15. In this embodiment, "car body 20 side" refers to the area electrically belonging to the car body 20 side with the grounding resistor 23 as the boundary, and "rail 21 side" refers to the area electrically belonging to the rail 21 side (vehicle grounding wire 22 side) with the grounding resistor 23 as the boundary. In this case, the main motor 18 is electrically connected to the rail 21 side. By placing the main motor 18 on the rail 21 side, electrolytic corrosion of the motor bearing can be suppressed. On the other hand, the power converter 16 is electrically connected to the car body side. The bogie 50 is the undercarriage of the railway vehicle, and the wheels 19, brakes, TC (track cleaning device), axle boxes, etc. are attached to the bogie frame 40. Since all mechanical connection parts are made of elastic components such as rubber, the bogie frame 40 is electrically insulated from the car body 20.

[0020] In the case of railway vehicles, for example, a power converter 16 for vehicle propulsion supplies drive current to the main motor 18. At that time, because there is a parasitic capacitance 32 between the windings inside the main motor 18 and the main motor frame, a portion of the drive current is converted into high-frequency noise current by this parasitic capacitance 32.

[0021] As a result, some of the high-frequency noise current flows as leakage current from the parasitic capacitance 32, etc., to the vehicle body 20, and the noise propagates to adjacent vehicles. This leakage current can cause potential fluctuations in the vehicle body 20 or radiate noise outside the vehicle body 20, potentially causing noise interference in signaling devices located in the lead or rear vehicle, leading to malfunctions or false detections. Furthermore, fluctuations in the potential of the lead or rear vehicle can cause fluctuations in the GND level of various electronic devices, potentially worsening the signal-to-noise ratio (S / N) of the signals.

[0022] Furthermore, in order to miniaturize and reduce the losses of the power converter 16, new semiconductor materials such as SiC (silicon carbide) are being increasingly adopted for power devices in recent years. As a result, the power converter 16 can perform even faster and higher frequency switching operations, satisfying the requirements for miniaturization and lower losses. However, the high-frequency noise current generated by the switching operation will have harmonic components at even higher frequencies. Therefore, measures to prevent leakage of high-frequency noise current that are effective at higher frequencies are required. The following describes the measures taken to prevent leakage of high-frequency noise current in Example 1.

[0023] The three-phase output line 17 is covered with metal shields 25a and 25b, which are examples of shielding. Hereafter, when metal shields 25a and 25b are not distinguished, they will simply be referred to as "metal shield 25". This metal shield 25 is connected to the car body 20, but because it electrically connects the car body 20 to the rails 21, the metal shield 25 cannot be electrically connected to the main motor 18. Furthermore, the areas between cars and on the bogie 50 are movable parts and therefore require flexibility. For this reason, a relay connector 26 is provided on the upper part of the bogie 50 to ensure flexibility. On the other hand, it is difficult to apply shielding to the metal shield 25 in a single unit from the power converter 16 to the main motor 18. Therefore, the metal shield 25 is divided and applied as metal shield 25a and metal shield 25a on the car body side and rail 21 side.

[0024] The three-phase output line 17 is electrically connected to the vehicle body 20 and the rail 21 via a relay connector 26, and the relay connector 26 also ensures flexibility. On the other hand, at the location of the relay connector 26, the metal shield 25 is divided into metal shield 25a and metal shield 25a on the vehicle body side and rail 21 side. As a result, the high-frequency noise current generated by conversion by the main motor 18 cannot use the metal shield 25 as its main return path, and instead flows through, for example, the path of the main motor 18, vehicle ground wire 22, ground resistor 23, vehicle body 20, and power converter 16 as its main return path. Because the ground resistor 23 itself has a high impedance and the vehicle ground wire 22 needs to be connected to the wheels, it is difficult to always run parallel to the three-phase output line 17, and because the loop area created by the path between the three-phase output line 17 and the return path is large, the impedance of the return path cannot be sufficiently reduced.

[0025] Therefore, in Embodiment 1, in order to prevent leakage of this high-frequency noise current, a capacitor 30 is placed in the relay connector 26 between the metal shield 25 and the power converter 16, and the metal shield 25a on the power converter 16 side and the metal shield 25b on the main motor 18 side are connected via this capacitor 30. More specifically, connection wires 31a and 31b are provided along with the capacitor 30, and the connection wires 31a and 31b are electrically connected to the respective divided metal shields 25a and 25b via the capacitor 30. In Embodiment 1, the capacitor 30 is also provided in the relay connector 26. Therefore, the connection wires 31a and 31b are electrically connected to the respective divided metal shields 25a and 25b via the capacitor 30 located in the relay connector 26. This allows the capacitor 30 to be placed using the relay connector 26.

[0026] In this case, at the relay connector 26, the metal shield 25a on the power converter 16 side and the metal shield 25b on the main motor 18 side are electrically insulated from each other via the capacitor 30. That is, at this point, the car body 20 side and the rail 21 side are electrically insulated. On the other hand, high-frequency noise current can pass through the capacitor 30 provided at the relay connector 26. This prevents a short circuit between the car body 20 and the rail 21, thus preventing the main current flowing from the overhead line 11 to the rail 21 from being drawn up to the car body 20 and concentrating on the grounding brushes 15 of the leading and trailing cars. Furthermore, with respect to high-frequency noise current, the continuity of the inverter noise return path can be maintained, so the high-frequency noise current can use the metal shield 25 as its main return path, preventing leakage to the rail 21 and other parts.

[0027] In particular, since the capacitor 30 is placed in the relay connector 26, it can always run parallel to the three-phase output line 17 and the metal shield 25. This strengthens the electromagnetic coupling between the three-phase output line 17 and the metal shield 25, and also prevents the metal shield 25 from being affected by external noise.

[0028] Here, the capacitor 30 may also function as a filter circuit including resistors. If resonance occurs in the metal shield 25, the effect of the resonance can be suppressed by configuring a filter circuit. Regarding the value of capacitor 30, it is desirable to set it to a value that provides a sufficiently high impedance to the main current flowing through rail 21 and a low impedance to high-frequency noise current.

[0029] In Embodiment 1, the noise current leakage prevention structure is provided, which includes a three-phase output line 17 that transmits power between a power converter 16 electrically connected to the vehicle body 20 and a main motor 18 electrically connected to the rail 21, metal shields 25a and 25b applied to the three-phase output line 17, and connecting lines 31a and 31b that are electrically connected to the metal shields 25a and 25b and also connect the vehicle body 20 and the rail 21 via a capacitor 30.

[0030] <Example 2> Next, we will describe Example 2 as an application example of Example 1. Figure 4 shows the circuit configuration diagram of the vehicle in Example 2. In Example 1, the capacitor 30 was placed on the relay connector 26, but it may also be placed on the frame of the main motor 18 or the bogie frame 40, provided that it is securely fixed and has sufficient vibration resistance. In Figure 4, the capacitor 30 is placed on the bogie frame 40, and the metal shield 25 and the capacitor 30 are connected by a connecting wire 31c. In this case, the metal shield 25 and the bogie frame 40 are electrically insulated because they are separated by the capacitor 30. That is, the vehicle body 20 side and the rail 21 side are electrically insulated at this point. In contrast, high-frequency noise current can pass through the capacitor 30 provided on the bogie frame 40. On the other hand, the relay connector 26 is configured so that the capacitor 30 is not provided as in Example 1, and the metal shield 25 is electrically connected. Even in this configuration, the continuity of the return path of the inverter noise can be maintained with respect to the high-frequency noise current, so the high-frequency noise current can use the shield material as its main return path, and leakage to the rail 21, etc., can be prevented.

[0031] In Embodiment 2, the noise current leakage prevention structure is provided, which includes a three-phase output line 17 that transmits power between a power converter 16 electrically connected to the vehicle body 20 and a main motor 18 electrically connected to the rail 21, a metal shield 25 applied to the three-phase output line 17, and a connecting line 31c that is electrically connected to the metal shield 25 and connects the vehicle body 20 and the rail 21 via a capacitor 30. In this embodiment 2, one end of the metal shield 25 (the power converter 16 side) is electrically connected to the vehicle body 20 side, and the other end of the metal shield 25 (the main motor 18 side) is connected to the rail 21 side via a capacitor 30 and a connecting wire 31c. In this case, the capacitor 30 can be placed using equipment that is electrically connected to the rail 21 side. Furthermore, the capacitor 30 is positioned on the bogie frame 40, and the other end of the metal shield 25 and the bogie frame 40 on the rail 21 side are connected via the capacitor 30 and a connecting wire 31c. Alternatively, the capacitor 30 may be positioned on the frame of the main motor 18, and the other end of the metal shield 25 and the main motor 18 on the rail 21 side may be connected via the capacitor 30 and a connecting wire 31c. In this case, the capacitor 30 can be positioned using the bogie frame 40 or the frame of the main motor 18.

[0032] <Example 3> Next, we will describe Example 3 as an application example of Example 1. Figure 5 shows the circuit configuration diagram of the vehicle in Example 3. The three-phase output line 17 is covered with a metal shield 25. In railway vehicles, the metal shield 25 and the vehicle body 20 are generally electrically connected at a single point. The reasons for this include the fact that onboard equipment basically uses the vehicle body 20 as the reference ground, so it is important to minimize the flow of noise current through the vehicle body 20, and because a potential difference occurs at the front and rear of the vehicle body 20, which is several tens of meters long, it is important to prevent noise current from flowing on the metal shield 25. However, if a high-frequency noise current flows through the metal shield 25, which is electrically connected to the vehicle body 20 at only one point, a potential difference will occur between the metal shield 25 and the vehicle body 20. Furthermore, due to its length, the metal shield 25 can act as a monopole antenna, becoming a new noise radiation source, and there is a risk that it may introduce noise by capacitively coupling with signal equipment.

[0033] Therefore, in Example 3, in order to suppress the potential difference between the vehicle body 20 and the metal shield 25, a high-dielectric material 34 is provided between the vehicle body 20 and the metal shield 25, which is placed on the terminal block 33. As a result, a branching point is provided that connects only high frequencies while being electrically insulated via the high-dielectric material 34. This makes it possible to suppress the potential difference in the metal shield 25, which is electrically connected to the vehicle body 20 at one point, while suppressing the flow of noise current in the vehicle body 20.

[0034] Figure 5 shows three connecting wires 31d that are electrically connected to the metal shield 25. One end of each connecting wire 31d is electrically connected to the metal shield 25. The leftmost connecting wire 31d in the figure is connected to the metal shield 25b, which is electrically on the rail 21 side. The other two are connected to the metal shield 25a, which is electrically on the vehicle body 20 side. In other words, the side of the connecting wire 31d that connects to the metal shield 25 can be either electrically on the vehicle body 20 side or the rail 21 side. The other end of the connecting wire 31d is connected to the terminal block 33 and connected to the vehicle body 20 side via a high dielectric material 34. However, the other end of the connecting wire 31d is insulated from the vehicle body 20 side by the high dielectric material 34.

[0035] Here, the high dielectric material 34 used for the connection between the vehicle body 20 and the metal shield 25 may be connected not only to electronic components such as capacitors mounted on a substrate, but also via parasitic capacitance composed of a planar conductor and an insulator from the vehicle body 20. This allows for a longer lifespan compared to using electronic components.

[0036] In Example 3, in addition to the configurations of Examples 1 and 2, the metal shield 25 is electrically connected, and at least one of the vehicle body 20 side and the rail 21 side, and the vehicle body 20 sides themselves are connected via a high-dielectric material 34, which is an example of a dielectric material. The high-dielectric material 34 is arranged, for example, on a terminal block 33. In this case, the high-dielectric material 34 can be arranged using the terminal block 33. Furthermore, as shown in the figure, it is preferable that the high dielectric material 34 is provided on each of the multiple terminal blocks 33 and connected to the vehicle body 20. In this case, the potential difference between the vehicle body 20 and the metal shield 25 can be further suppressed. In addition to the embodiments of Example 1 and Example 2, the above description also described a case in which the vehicle body 20 and the rail 21 are connected via the high dielectric material 34. However, the embodiments of Example 1 and Example 2 are not used, and the vehicle body 20 and the rail 21 are simply connected via the high dielectric material 34.

[0037] <Explanation of the effects of Examples 1 to 3> Figures 6(a) to 6(c) illustrate the effects of Examples 1 to 3. Here, (0a) represents the case where the metal shield 25 is not provided. Also, (0b) represents the case where the metal shield 25 is provided, but not in the form shown in Examples 1 to 3. That is, (0a) and (0b) illustrate a conventional vehicle drive circuit. In contrast, (1) is the result of using the vehicle drive circuit shown in Example 1. Also, (1+2) is the result of using the vehicle drive circuits shown in Example 1 and Example 2. Furthermore, (3) is the result of using the vehicle drive circuit shown in Example 3. However, (3) shows the case where the vehicle drive circuits of Examples 1 and 2 are not used.

[0038] Figure 6(a) shows the voltage between the vehicle body 20 and the rail 21 for (0a), (0b), (1), and (1+2). In Figure 6(a), the horizontal axis represents frequency and the vertical axis represents voltage. As shown in Figure 6(a), it can be seen that the voltage between the vehicle body 20 and the rail 21 is reduced in (1) and (1+2) compared to (0a) and (0b).

[0039] Figure 6(b) shows the rail currents for (0a), (0b), (1), and (1+2). In Figure 6(b), the horizontal axis represents frequency and the vertical axis represents current. As shown in Figure 6(b), it can be seen that the rail current is reduced in (1) and (1+2) compared to (0a) and (0b).

[0040] Figure 6(c) shows the voltage between the vehicle body 20 and the rail 21 for (0b) and (3). In Figure 6(c), the horizontal axis represents frequency and the vertical axis represents voltage. As shown in Figure 6(c), it can be seen that the voltage between the vehicle body 20 and the rail 21 is reduced in (3) compared to (0b).

[0041] Based on the above, the configuration shown in this embodiment provides a circuit configuration that suppresses the leakage of high-frequency noise current generated through the parasitic capacitance 32 between the winding portion of the main motor 18 and the main motor case when the power converter 16 drives the main motor 18 by supplying a drive current to it. Furthermore, it provides a noise current leakage prevention structure that can suppress the leakage of high-frequency noise current generated from the power converter 16.

[0042] The metal shield 25 described above is shown as being applied to cover the three-phase output wires 17, but it is not limited to this, and may be applied to cover only a part of the wires. For example, the three-phase output wires 17 may be fitted into a trough-shaped metal shield 25. The trough shape is a shape that has an opening in a direction intersecting the direction in which the metal shield 25 extends. Alternatively, it can be said that the cross-sectional shape in the direction intersecting the direction in which the metal shield 25 extends is concave. Furthermore, while the above-described configuration explains a circuit design that suppresses leakage of high-frequency noise current, it is not limited to the frequency of the noise current and can also be applied to low-frequency noise current. Furthermore, although a metal shield 25 was used as the shield in the configuration described above, it is not limited to this. The shield does not have to be made of metal; it may be, for example, a resin film with conductive particles dispersed in it, as long as it is conductive and has the function of shielding electromagnetic waves.

[0043] <Explanation of methods to prevent noise current leakage> The noise current leakage prevention structure described above is a method for preventing noise current leakage, in which, when transmitting power between a power converter 16 electrically connected to the vehicle body and a main motor 18 electrically connected to the rail 21, the metal shield 25 is electrically connected to the vehicle body and the vehicle body and the rail 21 are connected via a capacitor 30, thereby preventing noise current leakage.

[0044] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0045] 1...Drive vehicle, 2...Lead vehicle, 16...Power converter, 17...3-phase output line, 18...Main motor, 19...Wheel, 21...Rail, 25, 25a, 25b...Metal shield, 26...Intermediate connector, 30...Capacitor, 31a~31d...Connecting wire, 32...Parasitic capacitance, 33...Terminal block, 34...High dielectric material, 40...Bogie frame

Claims

1. A power transmission line that transmits power between a power converter electrically connected to the vehicle body and an electric motor electrically connected to the rails, A shield applied to the aforementioned power transmission line, A connecting wire that electrically connects to the shield and connects the vehicle body side and the rail side via a capacitor, A noise current leakage prevention structure equipped with [this feature].

2. The aforementioned shield is divided into a vehicle body side and a rail side. The noise current leakage prevention structure according to claim 1, wherein the connecting wire is electrically connected to each of the divided shields via the capacitor.

3. The aforementioned power transmission line is electrically connected to the vehicle body side and the rail side via a relay connector. The noise current leakage prevention structure according to claim 2, wherein the connecting wire is electrically connected to each of the divided shields via the capacitor arranged in the relay connector.

4. The noise current leakage prevention structure according to any one of claims 1 to 3, wherein one end of the shield is electrically connected to the vehicle body, and the other end of the shield is connected to the rail side via the capacitor and the connecting wire.

5. The noise current leakage prevention structure according to claim 4, wherein the capacitor is arranged on the frame of the electric motor, and the other end of the shield and the electric motor, which is on the rail side, are connected via the capacitor and the connecting wire.

6. The noise current leakage prevention structure according to claim 4, wherein the capacitor is arranged on the bogie frame, and the other end of the shield and the bogie frame, which is on the rail side, are connected via the capacitor and the connecting wire.

7. The noise current leakage prevention structure according to any one of claims 1 to 3, wherein the shield is electrically connected, and at least one of the vehicle body side and the rail side, and the vehicle body sides themselves are further connected via a dielectric.

8. The dielectric material is arranged on a terminal block in the noise current leakage prevention structure according to claim 7.

9. The noise current leakage prevention structure according to claim 8, wherein the dielectric is provided on each of the plurality of terminal blocks and connected to the vehicle body side.

10. The noise current leakage prevention structure according to claim 1, wherein the shield serves as a return path for leakage current generated due to the presence of parasitic capacitance in the electric motor.

11. A power transmission line that transmits power between a power converter electrically connected to the vehicle body and an electric motor electrically connected to the rails, A shield applied to the aforementioned power transmission line, A connecting wire electrically connects to the shield and connects at least one of the vehicle body side and the rail side, and the vehicle body sides to each other, via a dielectric. A noise current leakage prevention structure equipped with [this feature].

12. When power is transmitted between a power converter that is electrically connected to the vehicle body and an electric motor that is electrically connected to the rails, with shielding applied, By electrically connecting to the aforementioned shield and connecting the vehicle body side and the rail side via a capacitor, leakage of noise current is prevented. Method for preventing noise current leakage.

13. A metal body, A power conversion device that is electrically connected to the vehicle body and converts the supplied power into AC power, An electric motor that is electrically connected to the rails and uses converted AC power to rotate and drive the wheels, A power transmission line that transmits power between the power converter and the electric motor, A shield applied to the aforementioned power transmission line, A connecting wire that electrically connects to the shield and connects the vehicle body side and the rail side via a capacitor, An electric railway vehicle equipped with [a specific feature].

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