Drive system for a rail vehicle and method for installing said drive system

Abstract

To suppress an increase in size and cost of a power storage device by reducing the insulation performance required for the power storage device even when the serial number of storage batteries constituting the power storage device in a drive system for a railway vehicle is increased.SOLUTION: A drive system for a railway vehicle comprises: a plurality of converters which output DC voltage converted from AC voltage; a plurality of inverters which convert the DC voltage output from the converters into three-phase AC voltage to drive a motor; and a power storage device which has a serial storage battery group in which a plurality of storage batteries are serially connected and performs charging / discharging with the converters or the inverters. Each neutral point provided between DC rail tracks connecting each of the plurality of converters and each of the plurality of inverters corresponding to the converters and any inter-storage battery potential point of the serial storage battery group in the power storage device are grounded.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a traction system for a railway vehicle equipped with a storage battery and a method for installing said traction system. [Background technology]

[0002] In recent years, due to the increasing energy density and power density of storage batteries such as lithium-ion batteries, railcars equipped with power storage devices that can travel over 100 km on a single charge have been introduced. In such railcars, multiple storage batteries are connected in series and parallel to ensure input power to multiple inverter devices that drive the motors and auxiliary power devices that supply power to vehicle auxiliaries such as air conditioning.

[0003] On the other hand, an increase in the number of storage batteries connected in series requires high insulation performance (eg, insulation resistance, voltage resistance), which results in an increase in the size and cost of the power storage device.

[0004] Furthermore, Patent Document 1 (JP 2016-135030 A) discloses a technology in which a metal box that houses battery packs is insulated from the railway vehicle by an insulating material. In this technology, each battery pack box is made of resin for insulation, thereby reducing the insulation performance required for the devices and parts housed in the battery pack boxes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-135030 A Summary of the Invention [Problem to be solved by the invention]

[0006] When supplying power from a storage device to a main conversion device and an auxiliary power supply device composed of multiple converter devices and inverter devices, increasing the number of storage batteries connected in series that make up the storage device requires high insulation performance (e.g., insulation resistance, voltage resistance), which results in the storage device becoming larger and more expensive.

[0007] Therefore, an object of the present invention is to provide a drive system that can reduce the insulation performance required of the energy storage device and suppress the increase in size and cost of the energy storage device even if the number of series-connected storage batteries that make up the energy storage device increases. [Means for solving the problem]

[0008] In order to solve the above problems, one representative railway vehicle traction system according to the present invention includes a plurality of converters that output a DC voltage converted from an AC voltage, a plurality of inverters that convert the DC voltage output by the converters into a three-phase AC voltage to drive an electric motor, and a storage device having a series battery group in which a plurality of batteries are connected in series and performing charging and discharging between the converters or the inverters, in which each neutral point provided between each of the lines of DC lines connecting each of the multiple converters and each of the multiple inverters corresponding to the converters, and any inter-battery potential point of the series battery group in the storage device are grounded. Effect of the Invention

[0009] According to the present invention, the insulation performance required for the power storage device is reduced, and therefore it is possible to prevent the power storage device from becoming larger and more expensive in order to ensure the insulation performance. Furthermore, problems, configurations and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of a basic configuration of a railway vehicle equipped with a railway vehicle drive system according to an embodiment of the present invention. [Diagram 2]FIG. 1 is a diagram showing an example of a configuration in which a drive device according to an embodiment is mounted on an AC electric railcar. [Diagram 3] FIG. 1 is a diagram showing an example of a configuration in which a drive device according to an embodiment is mounted on a DC electric railcar. [Figure 4] 3 is a diagram illustrating an example of a schematic configuration of a converter device in FIG. 2. [Diagram 5] 3 is a diagram showing another example of the schematic configuration of the converter device in FIG. 2. [Figure 6] 3 is a diagram showing yet another example of a schematic configuration of the converter device in FIG. 2. [Figure 7] 4 is a diagram illustrating an example of a schematic configuration of the DC / DC converter device in FIG. [Figure 8] 4 is a diagram showing an example of a schematic configuration of the power storage device in FIG. 2 and FIG. 3 and a connection state with a main converter. FIG. [Figure 9] FIG. 13 is a diagram showing a current path when the neutral point and the battery potential point are individually grounded. [Figure 10] FIG. 13 is a diagram showing a current path when the neutral point and the battery potential point are connected to ground. [Figure 11] 11 is a diagram showing a path of a current flowing between two groups in a main converter when a power storage device is not equipped with a reactor. FIG. [Figure 12] 1 is a diagram showing a path of a current that flows when a power storage device is charged in a case where the power storage device is equipped with a reactor. [Figure 13] FIG. 1 is a diagram showing a schematic configuration of a reactor using individual iron cores. [Figure 14] FIG. 1 is a diagram showing a schematic configuration of a reactor having a common core. [Figure 15] FIG. 2 is a diagram illustrating an example of an internal configuration of a cutoff device. [Figure 16] FIG. 13 is a diagram illustrating another example of the internal configuration of the cutoff device. [Figure 17] 11 is a diagram showing a current path when a positive electrode or a negative electrode of a power storage device is short-circuited. [Figure 18] 11 is a diagram showing a current path when a positive electrode of a power storage device has a ground fault. FIG. [Figure 19]11 is a diagram showing a current path when a negative electrode of a power storage device has a ground fault; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, with reference to the drawings, an embodiment will be described as a mode for carrying out the present invention. Note that the present invention is not limited to this embodiment. Note that in the description of the drawings, the same reference numerals are used for common parts, duplicated explanations are omitted, and components that do not directly affect the present invention (e.g., sensors, controllers, etc.) are omitted. EXAMPLES

[0012] FIG. 1 is a diagram showing an outline of a basic configuration of a railway vehicle equipped with a railway vehicle traction system according to an embodiment of the present invention. The basic configuration shown in FIG. 1 is a vehicle 1a equipped with a drive device 21 according to the present invention and a vehicle 1b not equipped with a drive device.

[0013] Car 1a is supported on rails 11 by bogie 2a having wheels 3a and 3b, and bogie 2b having wheels 3c and 3d. Car 1b similarly has bogie 2c having wheels 3e and 3f, and bogie 2d having wheels 3g and 3h. Cars 1a and 1b are coupled with inter-car couplers 6 to form a train formation. However, the train formation is not limited to the form shown in FIG. 1. It is also possible to operate with only car 1a without coupling car 1b.

[0014] FIG. 2 is a diagram showing an example of a configuration in which the driving device 21 according to the embodiment is mounted on an AC electric railcar. The drive device 21 is composed of a transformer 7, a main converter 8, an electric motor 17, a power storage device 9, an auxiliary power supply device 10 and vehicle accessories 19, and takes in AC power from the power collector 5 through the overhead lines 4 into the vehicle.

[0015] The transformer 7 transforms the AC power taken in by the current collector 5 to an appropriate voltage value and outputs it to the main converter 8 .

[0016] The main conversion device 8 is composed of a converter device 14 and an inverter device 15, and performs the required power conversion to drive the electric motor 17. Of these, the converter device 14 converts the AC voltage input from the transformer device 7 into a DC voltage, and the inverter device 15 converts the DC voltage converted by the converter device 14 into the required three-phase AC voltage to drive the electric motor 17.

[0017] The power storage device 9 is connected to the DC line of the main conversion device 8, and is charged by the output power of the converter device 14 or the regenerative power from the inverter device 15, and can be discharged at any time.

[0018] The auxiliary power supply 10 is connected to the DC line of the main converter 8, converts DC power into AC power, and supplies the AC power to vehicle auxiliaries 19 such as an air conditioner and lighting within the vehicle.

[0019] FIG. 3 is a diagram showing an example of a configuration in which the driving device 21 according to the embodiment is mounted on a DC railcar. The drive device 21 is composed of a DC / DC converter device 36, an inverter device 15, an electric motor 17, a power storage device 9, an auxiliary power supply device 10 and vehicle accessories 19, and takes in DC power from the power collector 5 through the overhead line 4 into the vehicle.

[0020] The DC / DC converter device 36 transforms the DC voltage input from the current collector 5 into an appropriate DC voltage value and inputs it to the inverter device 15, the power storage device 9, and the auxiliary power supply device 10. The other configurations are similar to those shown in Fig. 2, so the description will be omitted.

[0021] Here, the converter device 14 shown in Figure 2 has a neutral point potential on the output side, and it is sufficient if the voltage applied to the transformer device 7 can be controlled by a switching element (not shown) that constitutes the converter device 14 (switching element 26 shown in Figures 4 to 6).

[0022] Moreover, the DC / DC converter device 36 shown in FIG. 3 is required only to be insulated between the overhead line side (hereinafter referred to as the "primary side") and the inverter device side (hereinafter referred to as the "secondary side"), to have a neutral potential on the secondary side which corresponds to the output side, and to be capable of supplying power in both directions.

[0023] Next, configuration examples of the converter device 14 are shown in FIGS. 4 to 6, and a configuration example of the DC / DC converter device 36 is shown in FIG.

[0024] FIG. 4 is a diagram showing an example of a schematic configuration of the converter device 14 in FIG. The converter device 14 is composed of two groups, a single-phase three-level converter 14a on the first group side and a single-phase three-level converter 14b on the second group side. Here, the first group and the second group are electrically in parallel, and a plurality of converters are provided to satisfy the required conversion power. However, it is not necessarily required to have a two-group configuration.

[0025] Each of the single-phase three-level converters 14a and 14b is composed of capacitors 16a and 16b, a switching element 26, a diode 27, and a grounding resistor 37. The capacitors 16a and 16b are connected in series, and their midpoint is grounded as a neutral point 102. Therefore, the upper capacitor 16a has a positive voltage to ground, and the lower capacitor 16b has a negative voltage to ground.

[0026] The neutral point 102 of the single-phase three-level converters 14a and 14b is also the connection point between the capacitors 16a and 16b, is electrically connected to the neutral point 102 via the ground resistor 37, and is connected to the earth 100 and grounded.

[0027] The single-phase three-level converters 14a and 14b switch the switching element 26 on and off to apply a pulsed AC voltage to the transformer device 7. The applied voltage has three levels: 0[V], ±|E|[V], and ±2|E|[V], where |E|[V] is the absolute voltage of each of the capacitors 16a and 16b.

[0028] Furthermore, the single-phase three-level converters 14 a and 14 b control the voltage applied to the transformer device 7 , and generate the DC voltage required for the inverter device 15 , the auxiliary power supply device 10 , and the power storage device 9 .

[0029] The inverter device 15 that receives the output of the converter device 14 is equipped with one or more circuits that convert DC power into AC power.

[0030] FIG. 5 is a diagram showing another example of the schematic configuration of the converter device 14 in FIG. The configuration of the single-phase three-level converters 14a and 14b shown in Fig. 5 does not require the diode 27 compared to the configuration of the single-phase three-level converters 14a and 14b shown in Fig. 4. Also, in each operation mode of the converter device 14, the number of switching elements and diodes through which current passes is reduced, resulting in high efficiency.

[0031] In addition, the configurations of the single-phase three-level converters 14a and 14b shown in FIG. 5 are different from the configuration shown in FIG. 4 as described above, but the manner of grounding the neutral point 102, which is also the connection point between the capacitors 16a and 16b, and the voltage applied to the transformer device 7 are the same as in the case of FIG. 4.

[0032] FIG. 6 is a diagram showing yet another example of a schematic configuration of the converter device 14 in FIG. The configuration shown in Fig. 6 can be made smaller than the configurations shown in Fig. 4 and Fig. 5 because the number of switching elements 26 is reduced. The converter device 14 is composed of two groups: a single-phase two-level converter 14c on the first group side and a single-phase two-level converter 14d on the second group side.

[0033] Each of the single-phase two-level converters 14c and 14d is composed of capacitors 16a and 16b, a switching element 26, and a grounding resistor 37. A neutral point 102, which is a connection point between the capacitors 16a and 16b of each of the single-phase two-level converters 14c and 14d, is electrically connected via the grounding resistor 37 and is connected to a ground 100 and is grounded.

[0034] Furthermore, the output voltages of the single-phase two-level converters 14c and 14d to the transformer 7 have two levels, 0 [V] and ±2|E| [V], where |E| [V] is the absolute voltage of the capacitors 16a and 16b.

[0035] FIG. 7 is a diagram showing an example of a schematic configuration of the DC / DC converter device 36 in FIG. The DC / DC converter device 36 is composed of two groups: a first group DC / DC converter 36a and a second group DC / DC converter 36b. Here, the first group and the second group are electrically in parallel, and a plurality of converters are provided to satisfy the required conversion power. However, it is not necessarily required to have a two-group configuration.

[0036] Each of the DC / DC converters 36 a and 36 b is composed of capacitors 16 a , 16 b and 16 c , a switching element 26 , a transformer 35 and a ground resistor 37 .

[0037] The capacitors 16a and 16b are connected in series, and their midpoint is grounded as a neutral point 102. Therefore, the upper capacitor 16a has a positive voltage to ground, and the lower capacitor 16b has a negative voltage to ground.

[0038] A neutral point 102 of the DC / DC converters 36a and 36b is a connection point between the capacitors 16a and 16b, and is electrically connected to the earth 100 via the ground resistor 37 for grounding.

[0039] DC / DC converters 36a and 36b switch switching element 26 on and off to apply a pulsed AC voltage to transformer 35. They control the phase and amplitude of the voltage applied to both sides of transformer 35 to output a constant voltage to the primary side or secondary side.

[0040] The inverter device 15 that receives the output of the DC / DC converter device 36 is equipped with one or more circuits that convert DC power into AC power.

[0041] FIG. 8 is a diagram showing an example of a schematic configuration of the power storage device 9 in FIG. 2 and FIG. 3 and a connection state with the main converter 8. In FIG. In a power storage device, a plurality of storage batteries are generally connected in series and parallel, and the power storage device 9 shown in Fig. 8 also has a plurality of storage batteries 23 connected in series and parallel. The positive and negative sides of any one of the series-connected storage batteries 23 at an inter-battery potential point 101 are connected to the storage battery 23 via a fuse 39.

[0042] The positive and negative electrodes of the storage battery 9 are connected to the main converter 8 via a reactor 38 and a circuit breaker 30. In addition, a battery potential point 101 is connected to a ground 100 via a ground resistor 37 and is grounded.

[0043] A ground resistor 37 is connected to each of the neutral point 102 of the main converter 8 and the auxiliary power supply 10 and the inter-battery potential point 101 of the power storage device 9. Each ground resistor 37 is electrically connected at one point, and then connected to the earth 100 and grounded (the auxiliary power supply 10 is not shown in FIG. 8).

[0044] FIG. 9 is a diagram showing a current path when the neutral point and the battery potential point are individually grounded. If each device is individually grounded, a current flows to earth 100. This current is generated when the voltages between the positive and negative poles momentarily differ due to switching operations of main converter 8 and auxiliary power supply 10, or variations in the characteristics of capacitors 16a and 16b and storage battery 23. As a result, the current contains high-frequency components.

[0045] The earth 100 is electrically connected to the box housing that houses the drive unit 21 and the vehicle 1a. If a current containing high-frequency components flows, electromagnetic noise may adversely affect signaling devices on the ground.

[0046] FIG. 10 is a diagram showing a current path when the neutral point and the potential point between the storage batteries are connected and grounded. By using the configuration shown in FIG. 8, no current flows through earth 100 in an ideal state, as shown in FIG.

[0047] In reality, a minute current flows to earth 100 in the case shown in FIG. 10 as well, but it is smaller than in the case shown in FIG.

[0048] The reactor 38 provided in the power storage device 9 is intended to prevent inrush current and smooth the charge / discharge current, and furthermore, in the configuration shown in FIG. 8, prevents unnecessary current from flowing between the two groups in the main converter 8.

[0049] FIG. 11 is a diagram showing a path of a current flowing between two groups in the main converter 8 in the case where the power storage device 9 does not include a reactor 38. In FIG.

[0050] When a potential difference occurs between the positive electrode side capacitor 16a of the first group converter 14a and the second group converter 14b, a current flows through the path indicated by the dotted arrow in Fig. 11. When a potential difference occurs between the negative electrode side capacitor 16b of the first group converter 14a and the second group converter 14b, a current flows through the path indicated by the dashed line arrow in Fig. 11. The current flows from the group with the higher voltage to the group with the lower voltage.

[0051] 11 shows a state in which a current intended to charge and discharge the electricity storage device 9 flows to the other group due to a potential difference between the groups, and this current causes a power loss.

[0052] FIG. 12 is a diagram showing a path of a current that flows when the power storage device 9 is charged in a case where reactors 38 are mounted between the converters 14a and 14b and the positive and negative electrodes of the power storage device 9, respectively.

[0053] The charging current generates a magnetic field in the reactor 38, which gives the reactor 38 a high impedance against the current flowing in the opposite direction to the charging current. This prevents current from flowing between the groups, and reduces power loss. In addition, the ground resistor 37 can always suppress the current flowing between the groups, regardless of the state of the reactor 38.

[0054] Next, the configuration of the reactor 38 will be described. Since substantially the same current flows through the positive and negative poles of the reactor 38, the reactor is magnetically coupled to achieve miniaturization.

[0055] FIG. 13 is a diagram showing a schematic configuration of a reactor 38 using individual iron cores 42. As shown in FIG. This corresponds to a typical case in which the reactor 38 is configured with coils each having an iron core 42 on the positive and negative sides.

[0056] On the other hand, FIG. 14 is a diagram showing a schematic configuration of a reactor 38 in which an iron core 42 is made common. The reactor 38 is configured by winding two windings, one for the positive pole side and one for the negative pole side, around one iron core 42. Therefore, the positive pole side and the negative pole side coils are magnetically coupled.

[0057] The configuration shown in Fig. 14 can be made smaller than the configuration shown in Fig. 13 because it has only one iron core 42. The positive and negative windings are connected to the storage battery 23 and the main converter 8 so that the current flows in a direction that reinforces the magnetic flux in the iron core.

[0058] Furthermore, the configuration of the cutoff device 30 will be described. In order to prevent a situation in which only the positive side or only the negative side is charged or discharged with respect to the neutral point 102, resulting in a voltage mismatch, the positive side and the negative side of the circuit breaker 30 need to operate in conjunction with each other.

[0059] 15 and 16 are diagrams each showing an example of the internal configuration of the cutoff device 30. As shown in FIG. 15 shows a configuration in which a circuit breaker 30a having a plurality of main contacts 43 is used as the circuit breaker 30. The two main contacts 43 are operated when a voltage is applied to an operating coil 44. An operating relay 45 switches between application and non-application of a voltage to this operating coil 44. Each of the two main contacts 43 is connected to a respective DC line of the main converter 8 (see FIG. 8).

[0060] FIG. 16 shows a configuration in which two circuit breakers, a circuit breaker 30b and a circuit breaker 30c, are used as the circuit breaker 30, and the auxiliary contact 46 of the circuit breaker 30c is connected to the operating coil 44 of the circuit breaker 30b. When the operation relay 45 is closed to apply a voltage to the operating coil 44 of the circuit breaker 30c, the main contact 43 and the auxiliary contact 46 of the circuit breaker 30c operate in conjunction with each other. The operation of the auxiliary contact 46 switches between application and non-application of a voltage to the operating coil 44 of the circuit breaker 30b, so that the main contact 43 of the circuit breaker 30b operates in conjunction with the main contact 43 of the circuit breaker 30c. The main contacts 43 of the circuit breaker 30b and the circuit breaker 30c are each connected to a DC line of the main converter 8 (see FIG. 8).

[0061] The circuit breaker 30 shown in FIG. 15 can be made compact because it can be configured with a single circuit breaker, but since it is limited to circuit breakers having multiple main contacts, it may not be possible to select a circuit breaker with optimal specifications.

[0062] The circuit breaker 30 shown in Fig. 16 uses multiple circuit breakers, so it is larger than the configuration shown in Fig. 15, but since it only requires one or more main contacts, all circuit breakers can be selected. The operation relay 45 is operated by the control of the drive device 21.

[0063] Furthermore, fuse 39 shown in FIG. 8 is configured so as to be capable of cutting off current when electricity storage device 9 experiences an internal short circuit or a ground fault.

[0064] 17 is a diagram showing a current path when a short circuit occurs at the positive electrode or the negative electrode of the electricity storage device 9. A current flows through a short-circuited point 40, but can be cut off by a fuse 39.

[0065] Fig. 18 is a diagram showing a current path when a ground fault occurs at the positive electrode of the power storage device 9. A current flows through a ground-fault location 41, but can be cut off by a fuse 39 (indicated by an x ​​in Fig. 18). Fig. 19 is a diagram showing a current path when a ground fault occurs at the negative electrode of the power storage device 9. A current flows through a ground-fault location 41, but can be cut off by a fuse 39 (indicated by an x ​​in Fig. 19).

[0066] 18 and 19, ground resistor 37 suppresses the current value to prevent equipment failure caused by the current that flows until fuse 39 is tripped. Furthermore, even at ground fault locations 41 other than those shown in Fig. 18 and 19, the current always passes through fuse 39, making it possible to trip the fault. However, this is premised on the fact that a sufficient current flows for fuse 39 to trip in the event of a short circuit or ground fault.

[0067] The storage batteries 23 included in the power storage device 9 are common to the first and second groups, which allows for a reduction in the number of wirings. If the storage batteries 23 were independent for each group, it would be necessary to install an equal number of storage batteries 23 in each group, but if they are common to the groups, the number of storage batteries 23 can be optimized.

[0068] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. [Explanation of symbols]

[0069] 1a, 1b...vehicle, 2a, 2b, 2c, 2d...bogie, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h...wheels, 4...overhead wire, 5...current collector, 6... inter-car coupler, 7... transformer, 8... main converter, 9... power storage device, 10... auxiliary power supply device, 11... rail, 14... converter device, 14a, 14b... single-phase three-level converter, 14c, 14d... single-phase two-level converter, 15... inverter device, 16a, 16b, 16c...capacitor, 17...motor, 19...vehicle auxiliary device, 21: drive device, 23: storage battery, 26: switching element, 27: diode, 30... circuit breaker, 30a, 30b, 30c... circuit breaker, 35... transformer, 36...DC / DC converter device, 36a, 36b...DC / DC converter, 37...ground resistor, 38...reactor, 39...fuse, 40...short circuit location, 41...ground fault location, 42...iron core, 43...main contact, 44...operating coil, 45...operating relay, 46...Auxiliary contact, 100...Earth, 101...Battery potential point, 102...Neutral point

Claims

1. A plurality of converters that convert AC voltages and output DC voltages; a plurality of inverters that convert the DC voltage output by the converter into a three-phase AC voltage to drive an electric motor; a power storage device having a series battery group in which a plurality of batteries are connected in series, and performing charging and discharging between the converter or the inverter; Equipped with Each neutral point provided between each of the DC lines connecting each of the plurality of converters and each of the plurality of inverters corresponding to the converter and any inter-battery potential point of the series storage battery group in the power storage device are grounded.

1. A drive system for a rail vehicle.

2. 2. A drive system for a rail vehicle according to claim 1, Each of the neutral points is a midpoint of a series circuit of a plurality of capacitors provided between each of the DC lines.

1. A drive system for a rail vehicle.

3. A drive system for a railway vehicle according to claim 1 or 2, The neutral points and the battery potential point are each connected to ground via a resistor.

1. A drive system for a rail vehicle.

4. A drive system for a railway vehicle according to any one of claims 1 to 3, The positive and negative electrodes of the storage device are connected to the positive and negative sides of the DC lines via reactors, respectively.

1. A drive system for a rail vehicle.

5. A drive system for a rail vehicle according to claim 4, The reactor connected to the positive electrode of the power storage device and the reactor connected to the negative electrode of the power storage device are magnetically coupled to each other.

1. A drive system for a rail vehicle.

6. A drive system for a railway vehicle according to any one of claims 1 to 5, The positive and negative electrodes of the storage device are connected to the positive and negative sides of the DC lines via breakers, respectively.

1. A drive system for a rail vehicle.

7. 7. A drive system for a rail vehicle according to claim 6, The breaker connected to the positive electrode of the power storage device and the breaker connected to the negative electrode of the power storage device are each configured by a single breaker having a plurality of main contacts.

1. A drive system for a rail vehicle.

8. 7. A drive system for a rail vehicle according to claim 6, The breaker connected to the positive electrode of the power storage device and the breaker connected to the negative electrode of the power storage device have a structure in which an auxiliary contact linked to one of the main contacts is connected to an operating coil of the remaining main contact.

1. A drive system for a rail vehicle.

9. A drive system for a railway vehicle according to any one of claims 1 to 8, A fuse is provided between the battery-interface potential point and the series-connected battery group on the positive electrode side of the power storage device, and between the battery-interface potential point and the series-connected battery group on the negative electrode side of the power storage device.

1. A drive system for a rail vehicle.

10. a plurality of converters that convert an AC voltage into a DC voltage and output the DC voltage; a plurality of inverters that convert the DC voltage output by the converters into a three-phase AC voltage to drive an electric motor; and an electric storage device having a series storage battery group in which a plurality of storage batteries are connected in series and performing charging and discharging between the series storage battery group and the converters or the inverters, the electric storage device being mounted on a railway vehicle as a drive system; Each neutral point provided between each of the DC lines connecting each of the plurality of converters and each of the plurality of inverters corresponding to the converter and any inter-battery potential point of the series storage battery group in the power storage device are grounded.

13. A method for installing a drive system for a rail vehicle, comprising:

11. 11. A method for installing a drive system for a rail vehicle according to claim 10, comprising the steps of: The intermediate points of a series circuit of a plurality of capacitors provided between the DC lines are grounded as the neutral points.

13. A method for installing a drive system for a rail vehicle, comprising:

12. 12. A method for installing a drive system for a rail vehicle according to claim 10 or 11, comprising the steps of: The neutral points and the battery potential point are connected to ground via resistors.

13. A method for installing a drive system for a rail vehicle, comprising:

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