Drive system and method for rail vehicles

Abstract

To achieve high safety by continuously supplying electric power to an auxiliary machine even when switching a plurality of storage batteries mounted on a storage battery-driven railroad train between series-connection and parallel-connection alternately.SOLUTION: A storage battery device comprises: a first shut-off tool that has a plurality of storage batteries and a switching part that switches between series-connection and parallel-connection of the plurality of storage batteries, and that shuts off electric power from a train wire to a DC link; a first electric power converting part that converts electric power from the DC link to electric power for driving a motor; a second electric power converting part that converts electric power from the DC link to electric power for charging the storage battery device; a third electric power converting part that converts electric power inputted from the DC link or the storage battery device to electric power for driving an auxiliary machine; a filter capacitor that is connected to an input side of the third electric power converting part; a second shut-off tool that shuts off electric power supplied from the storage battery device to the DC link; and first and second rectifying parts through which electric power is passed in a direction of the third electric power converting part, from the DC link and the storage battery device, where output points at the third electric power converting part side of the first and second rectifying parts are connected to positive electrodes of the filter capacitor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a traction system and a traction method for a railway vehicle equipped with a storage battery device that can switch the connection state of a plurality of storage batteries between series and parallel. [Background technology]

[0002] Regarding railway vehicles equipped with storage battery devices that can be switched between series and parallel, the following background art is available. Patent Document 1 states, "...the vehicle includes a converter, an inverter, a pair of DC links, a plurality of storage battery modules, a step-down chopper, and a switching circuit unit. The converter is configured to be able to convert single-phase AC power into DC power. The inverter is configured to be able to convert DC power into three-phase AC power. The pair of DC links connect the DC input / output side of the converter to the DC input / output side of the inverter. The plurality of storage battery modules are electrically connected to the pair of DC links. The step-down chopper is provided between the positive DC link of the pair of DC links and the positive sides of the plurality of storage battery modules." The switching circuit unit is configured to be able to step down DC power output from the positive DC link to the positive side of the plurality of storage battery modules. The switching circuit unit switches the electrical connection relationship of the plurality of storage battery modules between series and parallel among an AC power supply section receiving single-phase AC power from an AC system, a DC power supply section receiving DC power from a DC system, and a non-power supply section receiving no power from an external source, and also switches the electrical connection relationship between the pair of DC links, the plurality of storage battery modules, and the step-down chopper." (Paragraph 0005 describing "Means for Solving the Problems") is described as a technology to this effect.

[0003] Patent Document 2 describes the technology as follows: "...the power storage system comprises a battery unit, a first contactor, and a control unit. The battery unit has a plurality of secondary batteries whose connection pattern with other secondary batteries can be switched between series connection and parallel connection. The battery unit converts first AC power supplied via the secondary winding of a transformer that steps down power from an overhead line into traction power for driving a traction motor that runs the electric vehicle, and supplies the power to the traction motor, and to a DC load mounted on the electric vehicle. The first contactor is provided midway through the power line connecting the battery unit and the traction power conversion unit, and switches between a state in which power is cut off and a state in which power is conducted. When the electric vehicle is in a predetermined state and the first contactor is switched to a state in which power is conducted, the control unit supplies power to the traction power conversion unit by switching the connection pattern of the plurality of secondary batteries to a series connection." (paragraph 0005 describing "Means for Solving the Problems") [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-112795 [Patent Document 2] Japanese Patent Application Publication No. 2017-225323 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have conducted extensive research into a traction system for a railway vehicle equipped with a storage battery device that can be switched between series and parallel connections, and have come to the following findings. Patent Document 1 discloses that by switching the electrical connection relationship of multiple storage battery modules between series and parallel, and by switching the electrical connection relationship between a pair of DC links, multiple storage battery modules, and a step-down chopper, it is possible to travel in AC electrified sections, DC power supply sections, and non-powered sections without using a step-up chopper. However, Patent Document 1 does not disclose an auxiliary power conversion device or auxiliary equipment as on-board equipment, nor does it mention the supply of power to the auxiliary power conversion device and auxiliary equipment when switching the electrical connection relationship of multiple storage battery modules.

[0006] Here, when an auxiliary power conversion device and an auxiliary are mounted on a railway traction system equipped with a storage battery device that can be switched between series and parallel, the following problems may arise. When operating a battery system that can be switched between series and parallel connections, from a safety standpoint, it is necessary to disconnect the battery system from the main circuit when switching the battery system's connection. When the battery system is reconnected to the main circuit after switching, a voltage difference between the battery system and the overhead line may cause a large current to flow from the battery system to the overhead line or vice versa. Therefore, when connecting the battery system to the main circuit, it is necessary to disconnect the overhead line from the main circuit. In other words, the power supply to the main circuit is interrupted between the time the main circuit is disconnected from the overhead line and the time the battery system is reconnected to the main circuit, which results in an interruption of power supply to the auxiliary equipment.

[0007] Furthermore, Patent Document 2 discloses a technology for a railway vehicle equipped with a DC load such as an electronic device, excluding the traction motor, and a battery unit that is switchable between series and parallel and that supplies power to the DC load in principle, in which the battery unit can supply power to the DC load and the traction motor in the event of an emergency.

[0008] However, the technology disclosed in Patent Document 2 is designed for emergencies, and so when a train normally travels in a non-overlapping section where the DC load and the traction motor are driven by power from a storage battery, the following two problems can be considered. First, when supplying power to both the DC load and the traction motor, the battery unit is divided into two groups: the first group supplies power to the DC load in parallel, and the second group supplies power to the traction motor in series. As a result, the connection relationship of the battery as a whole is not switched from series to parallel, and a large battery capacity is required that can cover the combined power of the DC load and the traction motor.

[0009] Second, the power from the overhead lines to the DC load is split into two systems: the traction winding system uses high voltage to drive the traction motor, while the load winding system uses low voltage to charge the battery unit, drive the DC load, and drive the AC load. This requires more windings and power conversion equipment than when a single system of power from the overhead lines drives the traction motor, charges the battery unit, and drives the DC load. This limits the space available for installing batteries and other equipment. Furthermore, while charging the battery unit with low voltage from the load winding is sufficient for emergency operation of small battery units, it is not suitable for railway vehicles equipped with large battery units that regularly run on non-overhead sections.

[0010] Therefore, the present invention aims to provide a technology for a traction system for a railway vehicle equipped with a storage battery device that can be switched between series and parallel connections, which drives an electric motor, charges and discharges the storage battery device, and drives auxiliary equipment through a single DC link, and which continuously supplies power to the auxiliary equipment even when the connection state of the storage battery device is switched between series and parallel. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, one representative traction system for a railway vehicle of the present invention is a railway vehicle equipped with a storage battery device, the storage battery device having a plurality of storage batteries and a switching unit that switches the plurality of storage batteries between a series connection and a parallel connection, and the system includes a first circuit breaker that cuts off power supplied from an electric rail line to a DC link in the railway vehicle, a first power conversion unit that converts power input from the DC link into power for driving an electric motor, a second power conversion unit that converts power input from the DC link into power for charging the storage battery device, and a DC The power converter includes a third power conversion unit that converts power input from the DC link or the storage battery device into power to drive auxiliary equipment, a filter capacitor connected to the input side of the third power conversion unit, a second circuit breaker that cuts off power supplied from the storage battery device to the DC link, a first rectification unit that passes power from the DC link toward the third power conversion unit, and a second rectification unit that passes power from the storage battery device toward the third power conversion unit, and the output points of the first rectification unit and the second rectification unit on the third power conversion unit side are connected to the positive side of the filter capacitor. [Effects of the Invention]

[0012] According to the present invention, in a traction system for railway vehicles that uses a storage battery device that can be switched between series and parallel connections, the driving of the electric motor, the charging and discharging of the storage battery device, and the driving of the auxiliary equipment are all performed through a single DC link, and power is continuously supplied to the auxiliary equipment even when the connection state of the storage battery device is switched between series and parallel.This reduces the number of devices such as power conversion devices, increases the installation space for the storage battery and other devices, while continuously driving the auxiliary equipment and achieving greater safety for passengers. Problems, configurations, and effects other than those described above will become apparent from the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the configuration of a battery-powered driving system according to an embodiment; [Figure 2] FIG. 2 is a diagram showing the circuit configuration of a battery-powered drive system in a catenary mode. [Figure 3] FIG. 2 is a diagram showing the circuit configuration of a battery-powered drive system in a battery driving mode. [Figure 4] FIG. 10 is a diagram showing an example of a flowchart when the battery configuration of the battery-powered drive system is switched from parallel connection to series connection (overhead wire running mode → battery running mode). [Figure 5] FIG. 10 is a diagram showing an example of a flowchart when the battery configuration of the battery-powered drive system is switched from series connection to parallel connection (from battery running mode to overhead wire running mode). [Figure 6] FIG. 1 is a diagram showing the circuit configuration of a battery-powered drive system in a DC electric train mode. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, examples will be described as modes for carrying out the present invention with reference to the drawings. Note that the present invention is not limited to these examples. In addition, in the description of the drawings, the same parts are designated by the same reference numerals. [Example]

[0015] FIG. 1 is a diagram showing the configuration of a battery-powered driving system according to an embodiment of the present invention. The battery-powered traction system is a system for driving and controlling railway motors in both electrified and non-electrified sections. Specifically, the system consists of a current collector 1, a switch (high-speed circuit breaker for the current collector) 2, a power conversion unit (inverter) 3a, a filter capacitor for the inverter 3b, a motor 4, a power conversion unit (SIV) 5a for auxiliary equipment, a filter capacitor for the SIV 5b, an auxiliary load 6, a power conversion unit (DC / DC converter) 7a, a filter capacitor for the DC / DC converter 7b, power storage devices 8a and 8b, switches (contactors) 9a, 9b, 9c, 9d, and 9e for switching the series-parallel connection of the storage batteries, a switch (high-speed circuit breaker for the power storage device) 10, switches (contactors) 11 and 12, a charging circuit unit (for 3b and 7b) 13, a charging circuit unit (for 5b) 14, filter reactors 15 and 16, diodes 17 and 18, and a grounding unit 19. Each component will be described later.

[0016] The battery-assisted drive system of this embodiment can be broadly divided into the following three operation modes. Table 1 shows the operation modes distinguished by section and battery state. [Table 1]

[0017] As shown in Table 1, there are two possible combinations of vehicle location ("Section" in Table 1): electrified section or non-electrified section, and three possible combinations of the state of power storage devices 8a and 8b ("Battery State" in Table 1): series connection, parallel connection, or unused state (open state, not connected to the main circuit). Of the six combinations (2 patterns x 3 patterns), two patterns, the combination of a non-electrified section and a parallel connection of batteries, and the combination of a non-electrified section and an open state of batteries, are omitted as they are unlikely to occur in reality, leaving four patterns remaining.

[0018] Here, the vehicle modes are defined as shown in Table 1 above. The combination of an electrified section and a battery parallel connection state is called "overhead line running mode." The combination of non-electrified sections with batteries connected in series is called "battery-powered driving mode." The combination of the electrified section and the battery series connection state is called "battery driving mode (emergency)." This mode is assumed when some kind of problem occurs with the overhead lines or the vehicle, but since the circuit configuration is equivalent to the battery driving mode, it is considered an emergency mode. If an abnormality occurs in the power storage devices 8a and 8b, the combination of the electrified section and the open battery state is set to the "DC train mode." This mode is assumed when an abnormality occurs in power storage device 8a or 8b.

[0019] In addition, in either mode, it must be possible to supply power to the auxiliary load 6. Except in the event of an abnormality, the basic modes are "overhead line running mode" and "battery running mode," but switching between the two modes is performed at electrified stations that have overhead line equipment that can be charged. For example, this could be the terminal station of an electrified section.

[0020] Next, each component of the battery-powered driving system of this embodiment will be described. The current collector 1 serves to connect the electric rail and the on-board system. Here, the electric rail includes an overhead contact line and a third rail, etc. In this embodiment, an overhead contact line is used as the electric rail.

[0021] In DC electrified sections, the current collector 1 is brought into contact with DC overhead lines, and power is supplied to the vehicle system via the vehicle's DC link. This may involve stepping down the voltage from the current collector using a DC / DC converter before connecting to the DC link. On the other hand, in AC electrified sections, the current collector is brought into contact with AC overhead lines, and AC power is converted to DC power via a transformer and power converter before being connected to the DC link. Furthermore, the current collector 1 returns the regenerative energy of the vehicle to the overhead wires when the vehicle is braking.

[0022] A pantograph used for DC or AC overhead lines is typically used as the current collector 1, and this embodiment also assumes a pantograph as the current collector 1. If the current collector 1 is a pantograph, it is folded and stored in the vehicle in non-electrified sections. However, the current collector is not limited to a pantograph and also includes devices that collect current from a third rail. Furthermore, in this embodiment, when power is supplied from the overhead line through the current collector 1, driving of the electric motor 4, charging and discharging of the power storage devices 8a and 8b, and driving of the auxiliary load 6 are performed through a single DC link. This reduces the number of devices, such as power converters, required compared to when power from the pantograph is divided into two or more systems. This allows for an expansion of the installation space.

[0023] The switch (high-speed circuit breaker for current collector) 2 is installed between the current collector 1 and the DC link, and serves to electrically disconnect the vehicle system from the DC overhead line to prevent adverse effects on the DC overhead line when abnormal power is sent from the DC overhead line or when a problem such as a short circuit occurs in the vehicle's main circuit system. Generally, a switch that can interrupt current quickly and instantaneously is used.

[0024] Based on a command signal from a control unit (not shown), the power conversion unit (inverter) 3a converts DC power from the current collector 1 or the power storage devices 8a and 8b into three-phase AC power and outputs it to the electric motor 4. Furthermore, based on a command signal from a control unit (not shown), when the vehicle is braking, the power conversion unit (inverter) 3a converts the power generated by the electric motor 4 and outputs it to the DC overhead line or the power storage devices 8a and 8b.

[0025] Here, the power conversion unit (inverter) 3a is configured, for example, by a three-phase inverter including switching elements using power semiconductors, and is configured to output, for example, two-level or three-level voltages. The ON / OFF control of the switching elements of the power conversion unit (inverter) 3a is performed, for example, by PWM control or synchronous pulse control. Furthermore, in view of the lifespan of the elements and peripheral devices, an upper temperature limit is set for the power conversion unit (inverter) 3a, and protection control is performed to prevent it from reaching an overtemperature state.

[0026] The inverter filter capacitor 3b is connected to stabilize the operation of the power conversion unit (inverter) 3a and absorb harmonic components on the DC side, and is not allowed to retain charge when the vehicle power is off, primarily from the perspective of safety. To start the vehicle and operate the power conversion unit (inverter) 3a, the inverter filter capacitor 3b must be charged, for example, by a charging circuit 13. When charging or discharging the inverter filter capacitor 3b, it is desirable to avoid applying a large current due to a sudden voltage change, primarily from the perspective of lifespan.

[0027] The electric motor 4 generates driving force by controlling the power supplied from the DC overhead line and the power storage devices 8a and 8b via the current collector 1 using the power converter 3a. The electric motor 4 also operates as a generator when braking the vehicle, converting the kinetic energy and potential energy of the vehicle into electrical energy and outputting it to the power converter 3a. If the voltage driving the electric motor 4 is too high, there is a problem with the insulation voltage, and if the voltage is too low, there are problems with heat generation and reduced efficiency.

[0028] The power conversion unit (for auxiliary machinery, SIV) 5a supplies power to auxiliary loads 6, such as a power supply for a control unit (not shown), an air conditioning system in the vehicle, and interior lights. The power conversion unit (for auxiliary machinery, SIV) 5a generally has a DC link as its input side, and upper and lower limit ranges of voltage are set for stable operation. It is also desirable for the power conversion unit (for auxiliary machinery, SIV) 5a to operate constantly, whether the vehicle is running or stopped, to continue to stably supply power to the auxiliary loads 6. Here, the power conversion unit (for auxiliary machinery, SIV) 5a is configured, for example, by a three-phase inverter including switching elements using power semiconductors.

[0029] The SIV filter capacitor 5b is connected to stabilize the operation of the power conversion unit (for auxiliary machinery, SIV) 5a and absorb harmonic components on the DC side, and is not allowed to retain charge when the vehicle power is off, primarily from a safety standpoint. To start the vehicle and operate the power conversion unit (for auxiliary machinery, SIV) 5a, the SIV filter capacitor 5b must be charged, for example, by a charging circuit 14. When charging or discharging the SIV filter capacitor 5b, it is desirable to avoid applying a large current due to a sudden voltage change, primarily from the standpoint of lifespan.

[0030] The auxiliary loads 6 refer to loads that consume power in parts not directly related to the drive system, such as interior lights, air conditioning equipment, and control units. Basically, when the vehicle is running, the auxiliary loads 6 always require power, so it is desirable for them to be constantly supplied with power from the power conversion unit (for accessories, SIV) 5a. In particular, if the interior lights are turned off during nighttime operation, passenger safety cannot be ensured. Therefore, one option is to use secondary batteries such as lead-acid batteries or lithium-ion batteries as the power source for the interior lights, but this would result in a more complex vehicle design.

[0031] The power conversion unit (DC / DC converter) 7a converts DC power from the overhead line to charge the storage battery when the current collector 1 is connected to the overhead line. The power conversion unit (DC / DC converter) 7a is configured, for example, with a chopper that can step up and down voltage, in which the connection point between the upper arm and the lower arm is connected to the output side via a reactor.

[0032] DC / DC converter filter capacitor 7b is connected to stabilize the operation of power conversion unit (DC / DC converter) 7a and absorb harmonic components on the DC side, and is not allowed to retain charge when the vehicle power is off, primarily from a safety standpoint. To start the vehicle and operate power conversion unit (DC / DC converter) 7a, DC / DC converter filter capacitor 7b must be charged, for example, by charging circuit 13. When charging or discharging DC / DC converter filter capacitor 7b, it is desirable to avoid applying large currents due to sudden voltage changes, primarily from the standpoint of lifespan.

[0033] The power storage devices 8a and 8b serve as the main power source in non-electrified sections, and supply power to the electric motor 4 during power running. When braking, they absorb regenerative power generated by the electric motor 4 and reuse it for the next power running or to supply power to auxiliary equipment. Here, the power storage devices 8a and 8b are, for example, storage batteries such as lithium-ion batteries, which are rechargeable secondary batteries.

[0034] In order to ensure the safety of the power storage devices 8a and 8b and maximize their performance, it is common for a dedicated control board and control device (not shown) for the power storage devices to be provided. The voltage of a lithium-ion battery fluctuates depending on the charge level; generally, the higher the charge level, the higher the voltage, and the lower the charge level, the lower the voltage. The voltage change during this period exhibits different characteristics depending on the type of lithium-ion battery. Furthermore, in terms of degradation and lifespan, lithium-ion batteries have upper and lower limits on the charge level and voltage that can actually be used. Also, in terms of degradation, maximum charge and discharge currents are also set. Therefore, it is necessary to design the battery taking these factors into consideration.

[0035] 1 shows only the power storage devices 8a and 8b, but 8a and 8b may be made up of smaller units such as storage battery modules that make them up. Also, while Fig. 1 shows only one parallel storage device, there may be multiple power storage devices that have a similar series-parallel switchable configuration and are connected in parallel to the power storage devices 8a and 8b.

[0036] The connection method of the power storage devices 8a and 8b differs between electrified and non-electrified sections. In electrified sections, the power storage devices 8a and 8b are basically connected in parallel. In Japan, the overhead line voltage in DC electrified sections is approximately 1500V, but in reality, the overhead line voltage fluctuates between 1000V and 1800V depending on the relative positions of the substation and the load. In non-electrified sections, the power storage devices 8a and 8b are basically connected in series. Here, if the battery voltage when the power storage devices 8a and 8b are connected in series is designed to be equivalent to the overhead line voltage, there is a significant advantage in terms of circuit operation.

[0037] For example, if the battery voltage when the power storage devices 8a and 8b are connected in series is designed to be approximately 1500V, it becomes possible to drive the motor 4 and the auxiliary load 6 at the same voltage level in both electrified and non-electrified sections. Furthermore, in the electrified section, when the power storage devices 8a and 8b are connected in parallel, the battery voltage becomes approximately 750V. Even if the overhead line voltage fluctuates in the range of 1000 to 1800V, the power conversion unit (DC / DC converter) 7a only needs to perform a step-down operation, which is expected to simplify the hardware structure and control. Here, the overhead line voltage of 1500V is just an example, and the principles used in this embodiment are valid for voltages higher or lower.

[0038] Switches (contactors) 9a, 9b, 9c, 9d, and 9e are used to switch the series-parallel connection of the storage batteries. In practice, the series-parallel switching between the power storage devices 8a and 8b is performed when no current is flowing, so the interruption capability of the switches 9a to 9e may be low. When the storage batteries are connected in parallel, the switches 9a, 9b, 9d, and 9e are on (closed), and the switch 9c is off (open). On the other hand, when the storage batteries are connected in series, the switches 9a, 9c, and 9e are on (closed), and the switches 9b and 9d are off (open). Furthermore, to prevent a short circuit due to a direct connection between the high-potential side and the low-potential side of the power storage devices 8a and 8b, when the switches 9a, 9c, and 9e are on (closed), one or more of the switches 9d and 9e must not be on (closed).

[0039] Switch (high-speed circuit breaker for power storage device) 10 electrically disconnects power storage devices 8a and 8b from the vehicle system to prevent mutual adverse effects in the event of an abnormality in power storage devices 8a and 8b or a problem such as a short circuit in the vehicle's main circuit system. Generally, a switch capable of interrupting current quickly and instantaneously is used. It also turns off (opens) during series-parallel battery switching, electrically disconnecting power storage devices 8a and 8b from the main circuit system.

[0040] In battery-powered running mode, switch (contactor) 11 serves to connect the power storage devices 8a and 8b to the drive system consisting of the power conversion unit (inverter) 3a and the electric motor 4. The existence of the path formed when switch (contactor) 11 is on (closed) enables power running using the power of the power storage devices 8a and 8b and regeneration to the power storage devices 8a and 8b without being blocked by diodes 17 and 18, which will be described later. In overhead line running mode, switch (contactor) 11 must always be off (open). This is to prevent the generation of large currents due to direct connection of two different DC power sources, the overhead line and the power storage devices 8a and 8b, and the resulting equipment failures and accidents.

[0041] In the overhead wire running mode, switch (contactor) 12 is turned on (closed) and connects the output of power conversion unit (DC / DC converter) 7a to the high-potential side of power storage devices 8a and 8b to generate a current path during charging. In the battery running mode, power conversion unit (DC / DC converter) 7 does not operate, so switch (contactor) 12 is turned off (open).

[0042] The charging circuit unit (for 3b and 7b) 13 is composed of a parallel circuit of a resistor and a switch (a contactor or a switching element such as a semiconductor), and is responsible for charging the filter capacitor 3b for the inverter and the filter capacitor 7b for the DC / DC converter. To operate the power conversion unit (inverter) 3a and the power conversion unit (DC / DC converter) 7a, the filter capacitors 3b and 7b must be charged to a voltage equivalent to that of the DC power supply from the overhead line or storage battery. However, there is no charge when the vehicle's power supply is off.

[0043] The procedure for charging filter capacitors 3b and 7b is as follows: First, charging is performed up to a certain voltage using a path that goes through a resistor in charging circuit unit (for 3b and 7b) 13 while suppressing the charging current. Then, a switch (a switching element such as a contactor or semiconductor) is used to switch to a path that does not go through a resistor. Finally, power conversion unit (inverter) 3a and power conversion unit (DC / DC converter) 7a are operated using a path that does not go through a resistor and only uses a switch (a switching element such as a contactor or semiconductor). This series of operations takes into consideration resistance loss and heat generation. While charging circuit unit (for 3b and 7b) 13 shown in FIG. 1 has a simple configuration, the above-mentioned functions may also be achieved using multiple resistors and switches (switching elements such as contactors or semiconductors).

[0044] The charging circuit unit (for 5b) 14 is composed of a parallel circuit of a resistor and a switch (a switching element such as a contactor or semiconductor), and is responsible for charging the filter capacitor 5b for the SIV. To operate the power conversion unit (for auxiliary machinery, SIV) 5a, the filter capacitor 5b must be charged to a voltage equivalent to that of the DC power supply from the overhead line or storage battery. However, there is no charge when the vehicle power supply is off.

[0045] When the power supply to the power conversion unit (for auxiliary equipment, SIV) 5a alternates between the overhead line voltage and the power storage devices 8a and 8b, the voltage of the filter capacitor 5b must be adjusted using the charging circuit unit (for 5b) 14 to enable continuous operation of the auxiliary equipment. To adjust the voltage of the filter capacitor 5b, for example, first charge the filter capacitor 5b to a certain voltage while suppressing the charging current through a path that includes a resistor, and then switch to a path that does not include a resistor using a switch (a contactor or a switching element such as a semiconductor). Other methods include charging the filter capacitor 5b by adjusting the conduction rate using a switching element such as a semiconductor. Regardless of the method, once the filter capacitor 5b is adjusted to a voltage equivalent to the power supply voltage and the power conversion unit (for auxiliary equipment, SIV) 5a is operating normally, the path is switched to without a resistor, taking into account resistance loss and heat generation.

[0046] The filter reactor 15 acts as a low-pass filter to prevent harmonics generated by switching in the power conversion unit (inverter) 3a and the power conversion unit (DC / DC converter) 7a from leaking to the power supply. This configuration is commonly used in railway vehicles. Furthermore, in the event of a short circuit occurring in the power conversion unit (inverter) 3a or the power conversion unit (DC / DC converter) 7a, a filter reactor with a large inductance is generally selected to reduce the change in current per unit time.

[0047] The filter reactor 16 acts as a low-pass filter to prevent harmonics generated by switching in the power conversion unit (for auxiliary equipment, SIV) 5a from flowing out to the power supply side. It also has the function of reducing the current change per unit time when a short circuit occurs in the power conversion unit (for auxiliary equipment, SIV) 5a.

[0048] The diode 17 plays a role in smoothing the power on the input side of the power conversion unit (for auxiliaries, SIV) 5a when the power source of the power conversion unit (for auxiliaries, SIV) 5a is an overhead line. Diode 18 plays a role in smoothing the power on the input side of power conversion unit (for accessories, SIV) 5a when power storage devices 8a and 8b are used as the power source for power conversion unit (for accessories, SIV) 5a.

[0049] The cathodes of diodes 17 and 18 are connected at connection point 20. By connecting diodes 17 and 18 together, one of the diodes turns on depending on the magnitude relationship between the overhead line voltage and the voltages of the power storage devices 8a and 8b, making it possible to supply power to power conversion unit (for auxiliaries, SIV) 5a. Even if there is a voltage difference between the overhead line voltage and the voltages of the power storage devices 8a and 8b, no current flows between the power sources due to the blocking of the diodes that are off.

[0050] In a railway vehicle, the ground contact portion 19 corresponds to the wheels that come into contact with the metal rails. However, this is not the case when the wheels of the railway vehicle are rubber tires or the like, and the ground contact portion 19 may be the body earth.

[0051] FIG. 2 is a diagram showing the circuit configuration of the battery-powered drive system in the overhead line running mode. In the overhead line running mode, the power source for devices such as the electric motor 4 and auxiliary load 6 is the overhead line. The power storage devices 8a and 8b are connected in parallel with each other. The power storage devices 8a and 8b are charged by a power conversion unit (DC / DC converter) 7a. Examples include constant current charging, constant voltage charging, or CCCV charging, which is a combination of these. Charging is possible even while traveling on an electrified section. Since the total voltage of the parallel-connected storage batteries is generally lower than the overhead line voltage, diode 17 is on (conducting) and diode 18 is off (blocking).

[0052] FIG. 3 is a diagram showing the circuit configuration of the battery-powered drive system in the battery driving mode. In battery-powered running mode, the power sources for devices such as the electric motor 4 and auxiliary load 6 are the power storage devices 8a and 8b. The power storage devices 8a and 8b are connected in series. Charging the power storage devices 8a and 8b is performed through regenerative operation during braking. However, on flat sections, the amount of power that can be reused through regenerative operation generally does not exceed the power consumed during power running, so the charge rate tends to decrease as the train travels through non-electrified sections. It is important to manage the charge amount until the train arrives at the next station where charging is possible.

[0053] Fig. 4 is a diagram showing an example of a flowchart for switching the battery configuration of a battery-powered drive system from a parallel connection to a series connection (from overhead wire running mode to battery running mode). In Fig. 4 and Fig. 5, the overhead wire running mode is indicated as "Mode A" and the battery running mode is indicated as "Mode B."

[0054] Step 101 (S101) refers to the state in which charging of the battery is completed in the overhead line running mode at the charging station and a command to switch the mode to the battery running mode is issued. This command to switch modes may be issued by an operator using a switch, or may be issued automatically by the vehicle upon detecting the end of charging.

[0055] Furthermore, under normal circumstances, the train switches from the overhead line running mode to the battery running mode while the train is stopped at a station. Here, power storage devices 8a and 8b are connected in parallel with each other, and the voltages thereof are approximately equal.

[0056] In the state of step 101 (S101), power is supplied to the auxiliary load 6 from the power supplied from the overhead line. Since power is continuously supplied to the auxiliary load 6, the charging circuit section (for 5b) 14 is in a conductive state without passing through a resistor.

[0057] In step 102 (S102), the power conversion unit (inverter) 3a and the power conversion unit (DC / DC converter) 7a do not operate during the mode switching, so the operation of each power conversion unit is stopped.

[0058] In step 103 (S103), the charging circuit unit (for 3b and 7b) 13 of the stopped power conversion unit (inverter) 3a and power conversion unit (DC / DC converter) 7a is set to an open state and disconnected. Disconnection here refers to the electrical disconnection between the overhead line side and the input sides of the power conversion unit (inverter) 3a and power conversion unit (DC / DC converter) 7a. While disconnecting this charging circuit unit (for 3b and 7b) 13 is not essential, it is preferable to do so in order to prevent a large current generated by a voltage difference from flowing into the filter capacitors 3b and 7b when step 108 (S108), which will be described later, is executed.

[0059] In step 104 (S104), switch (contactor) 12 and switch (high-speed circuit breaker for power storage device) 10 are turned off (open). Either of these off (open) operations can be performed first. When switch (high-speed circuit breaker for power storage device) 10 is turned off (open), power storage devices 8a and 8b are disconnected from the main circuit system, and the series-parallel configuration can be rearranged.

[0060] In step 105 (S105), switches (contactors) 9b and 9d are turned off (opened). Regarding this turning off (opening) operation, it does not matter which is performed first, but it is recommended to turn off (open) switch 9b on the higher potential side first to prevent the potentials of power storage devices 8a and 8b from floating.

[0061] In step 106 (S106), switch (contactor) 9c is turned on (closed). This turns on (closes) the power storage devices 8a and 8b so that the total battery voltage is twice as high as that in the overhead line running mode. This completes the switch to a series connection of multiple batteries. In step 106 (S106), the series-parallel configuration of the multiple batteries is merely changed, and power to the auxiliary load 6 is still supplied from the overhead line.

[0062] In step 107 (S107), switch (high-speed circuit breaker for power storage device) 10 is turned on (closed). When this on (close) operation is performed, power storage devices 8a and 8b connected in series to the overhead line are connected via diodes 17 and 18, which have their cathodes butted together. The diode that is turned on (conducting) is determined depending on the magnitude relationship between the overhead line voltage (referred to as "Vf") and the total battery voltage of the series-connected power storage devices 8a and 8b (referred to as "Vbats" (=Voltage BATtery Series connection)). Step 108 (S108) shows the branching of this physical phenomenon.

[0063] In step 108 (S108), if the overhead line voltage Vf is greater than the total battery voltage Vbats of the series-connected power storage devices 8a and 8b (Yes), the diode 17 is turned on (conducting) and the diode 18 is turned off (blocking). In this case, power to the auxiliary load 6 is still supplied from the overhead line.

[0064] As for the filter capacitor 5b for the SIV, since it is already operated by the voltage of the overhead line, no voltage difference occurs even by step 108 (S108), so the charging circuit unit (for 5b) 14 does not need to perform any special operation and can simply maintain the conductive state. This is shown in step 109 (S109).

[0065] Since the mode is switched to battery-powered running mode, once step 109 (S109) is completed, the overhead line and the main circuit system must be electrically disconnected. This is done in step 111 (S111). In step 111 (S111), the switch (high-speed circuit breaker for current collector) 2 is turned off (opened) and the pantograph, which is the current collector 1, is stored. The order of these two steps does not matter, but it is generally better to turn off (open) the switch (high-speed circuit breaker for current collector) 2 first.

[0066] After step 111 (S111) is completed, the power supply path from the overhead line is cut off, so diode 17 is turned off (blocked). Also, since the voltage of filter capacitor 5b for SIV is equivalent to the overhead line voltage, diode 18 remains off (blocked) due to the condition Vf>Vbats.

[0067] While both diodes 17 and 18 are off (blocked), there is no power source connected to the power conversion unit (for auxiliaries, SIV) 5a. However, using the charge stored in the SIV filter capacitor 5b, the power conversion unit (for auxiliaries, SIV) 5a supplies power to the auxiliary load 6. Depending on the relationship between the capacitance of the SIV filter capacitor 5b and the power consumption of the auxiliary load 6, this operating mode continues for a period of time ranging from less than one second to several seconds.

[0068] As the SIV filter capacitor 5b discharges, the voltage decreases, and eventually the voltage on the anode side of the diode 18 becomes equal to or lower than Vbats. This causes the diode 18 to turn on (become conductive), and the power source for the auxiliary load 6 switches to the power storage devices 8a and 8b.

[0069] Next, the other condition in the branch at step 108 (S108) will be explained. In step 108 (S108), if the total battery voltage Vbats of the series-connected power storage devices 8a and 8b is greater than the overhead line voltage Vf (No), diode 18 is turned on (conducting) and diode 17 is turned off (blocking). Immediately before step 107 (S107) is performed, power was being supplied to the auxiliary load 6 from the overhead line, but now that diode 17 is turned off (blocking), power must be supplied from the power storage devices 8a and 8b. Because the voltage of the SIV filter capacitor 5b is equivalent to the overhead line voltage, diode 18 is turned on (conducting) due to the condition Vbats > Vf, and it is possible to immediately switch to power supply from the power storage devices 8a and 8b.

[0070] In this condition, it is assumed that a large current will flow into the SIV filter capacitor 5b depending on the voltage difference between Vbats and Vf. In this case, the charging circuit unit (for 5b) 14 can be switched to limit the current, and the SIV filter capacitor 5b can be charged with an appropriate charging current up to the total battery voltage Vbats of the series-connected power storage devices 8a and 8b. Step 110 (S110) corresponds to this operating mode.

[0071] At the time step 110 (S110) is executed, the power conversion unit (for auxiliary machinery, SIV) 5a is not receiving power supply from the overhead line, so in step 111 (S111), the switch (high-speed circuit breaker for current collector) 2 is turned off (open) and no problem occurs even if the pantograph, which is the current collector 1, is stored.

[0072] This concludes the explanation of the operation modes in both cases regarding the branching of step 108 (S108). In either branching condition, the power source of auxiliary load 6 is switched to power storage devices 8a and 8b, and there is no further branching of the state, so the remaining steps will be explained together.

[0073] It should be noted that the branching at step 108 (S108) is based on the physical circuit state. Generally, charging of the voltage of the filter capacitor 5b for the SIV is often performed by a control unit of the power conversion unit (for accessories, SIV) 5a (not shown) controlling the charging circuit unit (for 5b) 14. Therefore, there is no need to compare the magnitude of the voltages in the actual switching program and switch the sequence control depending on the comparison result. Therefore, at least one type of sequence control for switching from the overhead line running mode to the battery running mode is sufficient.

[0074] In step 112 (S112), switch (contactor) 11 is turned on (closed). This operation turns on (conducts) either diode 17 or diode 18. However, the power source of auxiliary load 6 remains the power storage devices 8a and 8b. Which diode actually turns on (conducts) is determined by the magnitude relationship of the resistance of the elements and wiring in the path.

[0075] By turning on (closing) switch (contactor) 11 in step 112 (S112), a path is formed from power storage devices 8a and 8b to power conversion unit (inverter) 3a and charging circuit unit (for 3b and 7b) 13 of power conversion unit (DC / DC converter) 7a without passing through diodes 17 and 18.

[0076] In step 113 (S113), the charging circuit unit (for 3b and 7b) 13 of the power conversion unit (inverter) 3a and the power conversion unit (DC / DC converter) 7a is operated to charge and discharge the filter capacitors 3b and 7b, which have been charged to a voltage equivalent to the overhead line voltage Vf, to a voltage equivalent to the total battery voltage Vbats of the series-connected power storage devices 8a and 8b. After voltage adjustment by charging and discharging the filter capacitors 3b and 7b is completed, the charging circuit unit (for 3b and 7b) 13 may be short-circuited.

[0077] After the above steps are performed, the mode switch to the battery driving mode is completed in step 114 (S114). The power storage devices 8a and 8b are now connected in series with each other, and power supply to the auxiliary load 6 can be continued without interruption during the mode switch.

[0078] FIG. 5 is a diagram showing an example of a flowchart when the battery configuration of the battery-powered drive system is switched from series connection to parallel connection (from battery running mode to overhead wire running mode). When the train has finished traveling in the non-electrified section in battery running mode and arrived at the charging station, it switches to overhead line running mode in order to charge the battery from the overhead line and travel in the electrified section. Step 201 (S201) is the state in which the train has stopped and a command has been issued to switch the mode to overhead line running mode. This command to switch modes may be issued by an operator using a switch, or it may be issued automatically by the train itself after detecting a stop in the electrified section and judging the charge rate of the battery.

[0079] Furthermore, under normal circumstances, the switching from the battery-powered running mode to the overhead line running mode is performed while the train is stopped at a station. The power storage devices 8a and 8b are connected in series to each other, and the voltages and capacities of the power storage devices 8a and 8b are equal to each other.

[0080] In step 201 (S201), the auxiliary load 6 is supplied with electric power from the power storage devices 8a and 8b. Since power is being steadily supplied to the auxiliary load 6, the charging circuit section (for 5b) 14 is in a conductive state without passing through a resistor.

[0081] In step 202 (S202), the power conversion unit (inverter) 3a does not operate during the mode switching, so the operation of the power conversion unit (inverter) 3a is stopped.

[0082] In step 203 (S203), the charging circuit units (for 3b and 7b) 13 of the stopped power conversion units (inverter) 3a and power conversion units (DC / DC converter) 7a are set to an open state and disconnected. Disconnection here refers to the electrical disconnection between the overhead line side and the input sides of the power conversion units (inverter) 3a and power conversion units (DC / DC converter) 7a. While disconnecting the charging circuit units (for 3b and 7b) 13 is not essential, it is preferable to do so in order to prevent a large current from flowing into the filter capacitors 3b and 7b when a large current is generated due to a voltage difference when step 205 (S205) described below is executed.

[0083] In step 204 (S204), the switch (contactor) 11 is turned off (open). As a result, power is supplied to the auxiliary load 6 via the diode 18, using the power storage devices 8a and 8b as a power source. By keeping the switch (contactor) 11 turned off (open) in this step 204 (S204), the overhead line and the power storage devices 8a and 8b are prevented from being directly connected when the overhead line is connected to the main circuit system by executing step 205 (S205) described later.

[0084] In step 205 (S205), the pantograph, which is the current collector 1, is brought into contact with the overhead wire, and the switch (high-speed circuit breaker for the current collector) 2 is turned on. When this operation is performed, the power storage devices 8a and 8b, which are connected in series with the overhead wire, are connected via diodes 17 and 18, which have their cathodes butted together. The diode that will be turned on (conducting) is determined depending on the magnitude relationship between the overhead wire voltage Vf and the total battery voltage Vbats of the series-connected power storage devices 8a and 8b. Step 206 (S206) shows the branching of this physical phenomenon.

[0085] In step 206 (S206), if the overhead line voltage Vf is greater than the total voltage Vbats of the series-connected storage batteries (Yes), diode 17 is turned on (conducting) and diode 18 is turned off (blocking). Immediately before step 206 (S206) is executed, power was being supplied to auxiliary load 6 from power storage devices 8a and 8b, but now that diode 18 is turned off (blocking), power must be supplied from the overhead line. Since the voltage of filter capacitor 5b for the SIV corresponds to the total voltage of the series-connected storage batteries 8a and 8b, due to the condition Vf>Vbats, diode 17 is turned on (conducting), and it is possible to immediately switch to power supply from the overhead line.

[0086] Note that under this condition of Vf>Vbats, a large current may flow into the SIV filter capacitor 5b depending on the voltage difference between Vf and Vbats. To deal with this situation, the charging circuit unit (for 5b) 14 can be switched to limit the current, allowing the SIV filter capacitor 5b to be charged to a level equivalent to the overhead line voltage Vf with an appropriate charging current. This is shown in step 207 (S207).

[0087] At the time when step 207 (S207) is executed, the power conversion unit (for auxiliary machinery, SIV) 5a switches to power supply from the overhead line, so by turning off (opening) the switch (high-speed circuit breaker for the storage device) 10 in step 209 (S209), no problem will occur even if the storage devices 8a and 8b are disconnected from the system.

[0088] Next, the other condition in the branch at step 206 (S206) will be explained. In step 206 (S206), if the total battery voltage Vbats of the series-connected power storage devices 8a and 8b is greater than the overhead line voltage Vf (No), the diode 18 is turned on (conducting) and the diode 17 is turned off (blocking). In this case, the power to the auxiliary load 6 is still supplied from the power storage devices 8a and 8b.

[0089] Since the filter capacitor 5b for the SIV is originally operated by the total battery voltage Vbats of the series-connected power storage devices 8a and 8b, no voltage difference occurs in this case, so the charging circuit unit (for 5b) 14 does not need to operate differently and can remain conductive. This is shown in step 208 (S208).

[0090] In order to switch the series / parallel connection of the power storage devices 8a and 8b, it is necessary to electrically disconnect the power storage devices 8a and 8b from the main circuit system after executing step 208 (S208). This operation mode is executed in step 209 (S209). In step 209 (S209), the switch (high-speed circuit breaker for the power storage device) 10 is turned off (opened).

[0091] After step 208 (S208) is executed, the power supply path from the power storage devices 8a and 8b is cut off, so that the diode 18 is turned off (blocked). In addition, since the voltage of the SIV filter capacitor 5b is equivalent to the total battery voltage Vbats of the series-connected power storage devices 8a and 8b, the diode 17 also remains in the off (blocked) state due to the condition Vbats>Vf.

[0092] While both diodes 17 and 18 are off (blocked), there is no power source connected to the power conversion unit (for auxiliary machinery, SIV) 5a. However, the power conversion unit (for auxiliary machinery, SIV) 5a supplies power to the auxiliary load 6 using the charge stored in the SIV filter capacitor 5b. This operating mode continues for a period ranging from approximately less than one second to several seconds, depending on the relationship between the capacitance of the SIV filter capacitor 5b and the power consumption of the auxiliary load 6. As the SIV filter capacitor 5b discharges, the voltage decreases, and eventually the voltage on the anode side of diode 17 becomes equal to or lower than Vf, causing diode 17 to turn on (conduct), and the power source for the auxiliary load 6 switches to the overhead line.

[0093] The above is the explanation of the operation modes in both cases regarding the branching of step 206 (S206). In either condition, the power source of the auxiliary load 6 is switched to the overhead line, and there is no further branching of the state, so the remaining steps will be explained together.

[0094] It should be noted that the branching at step 206 (S206) is based on the physical circuit state. Generally, charging of the voltage of the filter capacitor 5b for the SIV is often performed by a control unit of the power conversion unit (for auxiliary machinery, SIV) 5a (not shown) controlling the charging circuit unit (for 5b) 14. Therefore, there is no need to compare the magnitude of the voltages in the actual switching program and switch the sequence control depending on the comparison result. Therefore, at least one type of sequence control for switching from the battery-powered running mode to the overhead line running mode is sufficient.

[0095] In step 209 (S209), switch (high-speed circuit breaker for power storage device) 10 is turned off (open), whereby power storage devices 8a and 8b are disconnected from the main circuit system, and the series-parallel configuration can be rearranged.

[0096] In step 210 (S210), the switch (contactor) 9c is turned off (open).

[0097] In step 211 (S211), switches (contactors) 9b and 9d are turned on (closed). Regarding this on (close) operation, it does not matter which is performed first, but it is recommended to turn on (close) switch 9d on the lower potential side first to prevent the potentials of power storage devices 8a and 8b from floating. However, to prevent a short circuit between the storage batteries, step 211 (S211) must be performed after step 210 (S210). After step 211 (S211), the power storage devices 8a and 8b are connected in parallel with each other, and power is supplied to the auxiliary load 6 from the overhead line.

[0098] In step 212 (S212), switch (high-speed circuit breaker for power storage device) 10 is turned on (closed). At this time, since power storage devices 8a and 8b are connected in parallel, the voltage generally does not exceed the overhead line voltage, and diode 17 is on (conducting) and diode 18 is off (blocking).

[0099] In step 213 (S213), the charging circuit unit (for 3b and 7b) 13 is operated to charge and discharge the filter capacitors 3b and 7b, which have been charged to a voltage equivalent to the total battery voltage Vbats of the series-connected power storage devices 8a and 8b, to a voltage equivalent to the overhead line voltage Vf. After voltage adjustment by charging and discharging the filter capacitors 3b and 7b is completed, the charging circuit unit (for 3b and 7b) 13 can be short-circuited.

[0100] In step 214 (S214), switch (contactor) 12 is turned on (closed). This on (closed) state connects the output section of power conversion section (DC / DC converter) 7a to power storage devices 8a and 8b connected in parallel, enabling charging operation.

[0101] After the above steps are performed, the mode switching to the overhead line running mode is completed in step 215 (S215). The power storage devices 8a and 8b are now connected in parallel with each other, and power supply to the auxiliary load 6 can be continued without interruption during the mode switching.

[0102] As described above, we have explained the overhead line running mode and battery running mode that are the basic modes under normal circumstances, as well as the operating conditions when switching between the two modes and the fact that continuous power supply to the auxiliary load 6 is possible even in this case.

[0103] FIG. 6 is a diagram showing the circuit configuration of a battery-powered drive system in a DC electric railcar mode. Because switch (high-speed circuit breaker for power storage device) 10 and switch (contactor) 12 are off (open), power storage devices 8a and 8b are not connected to the main circuit system. This DC electric train mode is assumed to occur when a protective operation for power storage devices 8a and 8b is activated by a control unit (not shown) while the train is traveling mainly in an electrified section. The circuit configuration in this DC electric train mode is equivalent to the circuit configuration of a railway vehicle traveling on a normal DC section.

[0104] Furthermore, the above-described embodiment encompasses at least the following technical aspects. <Technical matters 1> In a traction system for a railway vehicle equipped with a storage battery device, the storage battery device has a plurality of storage batteries and a switching unit that switches between a series connection and a parallel connection of the plurality of storage batteries, and includes a first circuit breaker that cuts off power supplied from an electric railroad line to a DC link in the railway vehicle, a first power conversion unit that converts power input from the DC link into power for driving an electric motor, a second power conversion unit that converts power input from the DC link into power for charging the storage battery device, and a power converter that converts power input from the DC link into power for charging the storage battery device. The power converter includes a third power conversion unit that converts power input from the DC link into power for driving auxiliary equipment, a filter capacitor connected to the input side of the third power conversion unit, a second circuit breaker that cuts off power supplied from the storage battery device to the DC link, a first rectification unit that passes power from the DC link toward the third power conversion unit, and a second rectification unit that passes power from the storage battery device toward the third power conversion unit, and the output points of the first rectification unit and the second rectification unit on the third power conversion unit side are connected to the positive electrode side of the filter capacitor.

[0105] <Technical matters 2> In the traction system for railway vehicles described in Technical Item 1 above, when switching between power supply from the electric rail and power supply from the storage battery device, the multiple storage batteries are switched from a parallel connection to a series connection or from a series connection to a parallel connection, and the first rectifier unit or the second rectifier unit is made conductive depending on the magnitude relationship between the voltage of the electric rail and the voltage of the storage battery device connected in series, thereby continuing the power supply to the auxiliary equipment without interruption.

[0106] <Technical matters 3> In the traction system for a railway vehicle described in Technical Item 1 or Technical Item 2 above, a charging circuit is provided between the output points of the first rectifier unit and the second rectifier unit on the third power conversion unit side and the positive electrode side of the filter capacitor, and the voltage of the filter capacitor is adjusted.

[0107] <Technical matters 4> In the traction system for a railway vehicle described in Technical Item 3 above, the charging circuit is a parallel circuit of a semiconductor switch and a resistor.

[0108] <Technical matters 5> In the traction system for railway vehicles described in Technical Item 4 above, when there is a potential difference between the voltage of the electric rail or the voltage of the series-connected storage battery device and the voltage of the filter capacitor, the semiconductor switch is turned on and off to limit the charging current to the filter capacitor.

[0109] <Technical matters 6> A railway vehicle equipped with a railway vehicle drive system according to any one of Technical Item 1 to Technical Item 5 above.

[0110] <Technical matter 7> In a driving method for a railway vehicle, the railway vehicle is driven by power supplied from an electric power line to a DC link in the railway vehicle or by power supplied from a plurality of storage batteries mounted on the railway vehicle. The railway vehicle is equipped with a power converter that converts power input from the DC link or the plurality of storage batteries into power for driving auxiliary machinery. When the railway vehicle switches from a mode driven by power from the electric power line to a mode driven by power from the plurality of storage batteries, the plurality of storage batteries are disconnected from the DC link, the plurality of storage batteries connected in parallel are switched to a series connection, and the series connection is The system connects the multiple storage batteries connected in series to a DC link, and when the voltage of the electric power line is greater than the voltage of the multiple storage batteries connected in series, the first rectifier prevents the power input from the DC link from passing in the direction of the multiple storage batteries and the second rectifier passes the power in the direction of the power converter; and when the voltage of the multiple storage batteries connected in series is greater than the voltage of the electric power line, the second rectifier prevents the power input from the multiple storage batteries from passing in the direction of the electric power line and the first rectifier passes the power in the direction of the power converter, and then executes a sequence that disconnects the DC link from the electric power line.

[0111] <Technical matters 8> In the railway vehicle drive method described in Technical Item 7 above, when the railway vehicle switches from a mode powered by multiple storage batteries to a mode powered by electric power from the electric rail, the multiple series-connected storage batteries are disconnected from the DC link and the DC link is connected to the electric rail; if the voltage of the electric rail is higher than the voltage of the multiple series-connected storage batteries, the first rectifier prevents the power input from the DC link from passing toward the multiple storage batteries and the second rectifier passes the power toward the power converter; if the voltage of the multiple series-connected storage batteries is higher than the voltage of the electric rail, the second rectifier prevents the power input from the multiple storage batteries from passing toward the electric rail and the first rectifier passes the power toward the power converter; and when the power input from the DC link is supplied to the power converter, a sequence is executed to switch the multiple series-connected storage batteries to a parallel connection.

[0112] <Technical matters 9> In a driving method for a railway vehicle, the railway vehicle is driven by power supplied from an electric power line to a DC link in the railway vehicle or by power supplied from a plurality of storage batteries mounted on the railway vehicle. The railway vehicle is equipped with a power converter that converts power input from the DC link or the plurality of storage batteries into power for driving auxiliary machinery. When the railway vehicle switches from a mode driven by power from the plurality of storage batteries to a mode driven by power from the electric power line, the plurality of storage batteries connected in series are disconnected from the DC link, the DC link is connected to the electric power line, and the plurality of storage batteries connected in series are converted into power for driving auxiliary machinery. When the voltage of the electric power line is greater than the voltage of the electric power line, the first rectifier prevents the power input from the DC link from passing in the direction of the multiple storage batteries, and the second rectifier passes the power in the direction of the power converter; when the voltage of the multiple storage batteries connected in series is greater than the voltage of the electric power line, the second rectifier prevents the power input from the multiple storage batteries from passing in the direction of the electric power line, and the first rectifier passes the power in the direction of the power converter; and when the power input from the DC link is supplied to the power converter, a sequence is executed to switch the multiple storage batteries connected in series to a parallel connection.

[0113] <Technical matters 10> In the driving method for a railway vehicle described in any one of Technical Items 7 to 9 above, the railway vehicle includes a filter capacitor provided on the input side of the power converter, and a charging circuit provided between the DC link and the filter capacitor and the plurality of storage batteries, and when power from the electric rail or the plurality of storage batteries is input to the power converter, the voltage of the filter capacitor is adjusted by the charging circuit.

[0114] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0115] 1...current collector, 2...switch (high-speed circuit breaker for current collector), 3a...power conversion unit (inverter), 3b...filter capacitor for inverter, 4...electric motor, 5a...power conversion unit (for auxiliary machinery, SIV), 5b...Filter capacitor for SIV, 6...Auxiliary load, 7a...Power conversion section (DC / DC converter), 7b...filter capacitor for DC / DC converter, 8a, 8b...electricity storage device, 9a, 9b, 9c, 9d, 9e...Switches (contactors), 10...switch (high-speed circuit breaker for power storage device), 11, 12...switch (contactor), 13... Charging circuit section (for 3b and 7b), 14... Charging circuit section (for 5b), 15, 16...filter reactor, 17, 18...diode, 19...grounding part, 20...Connection point

Claims

1. In a drive system for a railway vehicle equipped with a storage battery device, the storage battery device includes a plurality of storage batteries and a switching unit that switches between a series connection and a parallel connection of the plurality of storage batteries; a first circuit breaker that cuts off power supplied from the electric power line to a DC link in the railway vehicle; a first power conversion unit that converts the power input from the DC link into power for driving an electric motor; a second power conversion unit that converts the power input from the DC link into power for charging the storage battery device; a third power conversion unit that converts the power input from the DC link or the storage battery device into power for driving an auxiliary device; a filter capacitor connected to the input side of the third power conversion unit; a second circuit breaker that cuts off power supplied from the storage battery equipment to the DC link; a first rectification unit that passes power from the DC link toward the third power conversion unit; a second rectification unit that passes electric power from the storage battery device to the third power conversion unit; Equipped with The output points of the first rectifier and the second rectifier on the third power conversion unit side are connected to the positive electrode side of the filter capacitor. A drive system for a railway vehicle.

2. 2. The drive system for a railway vehicle according to claim 1, When switching between the power supply from the electric power line and the power supply from the storage battery device, The plurality of storage batteries are switched from a parallel connection to a series connection or from a series connection to a parallel connection, and the first rectifier unit or the second rectifier unit is made conductive depending on the magnitude relationship between the voltage of the electric rail and the voltage of the storage battery device connected in series, thereby continuing the power supply to the auxiliary equipment without interruption. A drive system for a railway vehicle.

3. 3. The railway vehicle drive system according to claim 1, A charging circuit is provided between the output point and the positive electrode of the filter capacitor, and the voltage of the filter capacitor is adjusted. A drive system for a railway vehicle.

4. 4. The rail vehicle drive system according to claim 3, The charging circuit is a parallel circuit of a semiconductor switch and a resistor. A drive system for a railway vehicle.

5. 5. The drive system for a railway vehicle according to claim 4, When there is a voltage difference between the voltage of the electric rail or the voltage of the storage battery device connected in series and the voltage of the filter capacitor, the semiconductor switch is turned on and off to limit the charging current to the filter capacitor. A drive system for a railway vehicle.

6. A railway vehicle equipped with the railway vehicle drive system according to claim 1 or 2.

7. A method for driving a railway vehicle using power supplied from an electric power line to a DC link in the railway vehicle or power supplied from a plurality of storage batteries mounted on the railway vehicle, comprising: the railway vehicle includes a power converter that converts power input from the DC link or the plurality of storage batteries into power for driving auxiliary machinery; When the railway vehicle switches from a mode driven by electric power from the electric rails to a mode driven by electric power from the plurality of storage batteries, disconnecting the plurality of batteries from the DC link; Switching the parallel-connected storage batteries to a series connection; connecting the plurality of series-connected batteries to the DC link; when the voltage of the electric power line is higher than the voltage of the plurality of storage batteries connected in series, a first rectifier prevents the power input from the DC link from passing in the direction of the plurality of storage batteries, and a second rectifier passes the power in the direction of the power converter; when the voltage of the plurality of storage batteries connected in series is greater than the voltage of the electric rail, the second rectifier does not pass the power input from the plurality of storage batteries in the direction of the electric rail, but passes the power input from the plurality of storage batteries in the direction of the power converter, Execute a sequence to disconnect the DC link from the overhead contact line.

1. A driving method for a railway vehicle, comprising:

8. 8. A method for driving a railway vehicle according to claim 7, When the railway vehicle switches from a mode driven by power from the plurality of storage batteries to a mode driven by power from the electric rails, disconnecting the plurality of series-connected storage batteries from the DC link; connecting the DC link to the electric rail; when the voltage of the electric power line is higher than the voltage of the plurality of storage batteries connected in series, the first rectifier does not pass the power input from the DC link toward the plurality of storage batteries, but passes the power toward the power converter by the second rectifier; when the voltage of the plurality of storage batteries connected in series is greater than the voltage of the electric rail, the second rectifier does not pass the power input from the plurality of storage batteries in the direction of the electric rail, but passes the power input from the plurality of storage batteries in the direction of the power converter, When the power input from the DC link is supplied to the power converter, a sequence is executed to switch the series-connected storage batteries to a parallel connection.

1. A driving method for a railway vehicle, comprising:

9. A method for driving a railway vehicle using power supplied from an electric power line to a DC link in the railway vehicle or power supplied from a plurality of storage batteries mounted on the railway vehicle, comprising: the railway vehicle includes a power converter that converts power input from the DC link or the plurality of storage batteries into power for driving auxiliary machinery; When the railway vehicle switches from a mode driven by power from the plurality of storage batteries to a mode driven by power from the electric rails, disconnecting the plurality of series-connected storage batteries from the DC link; connecting the DC link to the electric rail; when the voltage of the electric power line is higher than the voltage of the plurality of storage batteries connected in series, a first rectifier prevents the power input from the DC link from passing in the direction of the plurality of storage batteries, and a second rectifier passes the power in the direction of the power converter; when the voltage of the plurality of storage batteries connected in series is greater than the voltage of the electric rail, the second rectifier does not pass the power input from the plurality of storage batteries in the direction of the electric rail, but passes the power input from the plurality of storage batteries in the direction of the power converter, When the power input from the DC link is supplied to the power converter, a sequence is executed to switch the series-connected storage batteries to a parallel connection.

1. A driving method for a railway vehicle, comprising:

10. 10. A driving method for a railway vehicle according to any one of claims 7 to 9, the railway vehicle includes a filter capacitor provided on an input side of the power converter, and a charging circuit provided between the DC link, the plurality of storage batteries, and the filter capacitor; When the power of the electric train line or the plurality of storage batteries is input to the power converter, the voltage of the filter capacitor is adjusted by the charging circuit.

1. A driving method for a railway vehicle, comprising:

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