CN108349397B

CN108349397B - Power conversion device for railway vehicle

Info

Publication number: CN108349397B
Application number: CN201680057216.9A
Authority: CN
Inventors: 清水阳介
Original assignee: Toshiba Corp; Toshiba Infrastructure Systems and Solutions Corp
Current assignee: Toshiba Corp; Toshiba Infrastructure Systems and Solutions Corp
Priority date: 2015-10-01
Filing date: 2016-06-21
Publication date: 2021-03-30
Anticipated expiration: 2036-06-21
Also published as: JPWO2017056588A1; JP6510060B2; CN108349397A; WO2017056588A1

Abstract

The power conversion device for railways of the embodiment is provided with: a transformer, a primary winding of which is electrically connected to the overhead line via a current collector; a main power conversion device connected to a secondary winding of the transformer and connected to the drive motor; a sub-power conversion device connected to a tertiary winding of the transformer and supplying electric power to an auxiliary machine mounted on a driven object of the railway vehicle; a cutting device for electrically cutting off the transformer and the overhead line; a detector provided between the overhead wire and the cutting device, and detecting the presence or absence of the supply of power from the overhead wire; and a control unit that causes the main power conversion device to supply the regenerative power of the drive motor to the sub power conversion device via the transformer in a state where the transformer and the overhead wire are electrically disconnected by the disconnection device during a passage period of the non-power section in which at least the supply of the power from the overhead wire is not performed based on the output of the detector, so that the supply of the large power to the auxiliary machine can be continued even when the section passes.

Description

Power conversion device for railway vehicle

Technical Field

An embodiment of the present invention relates to a power conversion device for a railway vehicle.

Background

Conventionally, an electric motorcycle that pulls or propels a passenger car or a truck is mounted with a sub-power conversion device that supplies electric power to an auxiliary machine such as an air conditioning device mounted on the passenger car or the truck, together with a main power conversion device that supplies electric power to a motor for driving the electric motorcycle.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-215013

Disclosure of Invention

However, in order to smoothly transfer an electric locomotive between overhead wires belonging to different power supply systems, an overhead wire that supplies electric power to the electric locomotive via a current collector such as a pantograph is provided with a section that is a dead zone to which no electric power is supplied between the overhead wires belonging to the different power supply systems.

When the electric power is supplied to the current collector, the electric power supply to the current collector is stopped, and therefore, when the electric power supply to the auxiliary equipment having a large electric power, such as the air conditioner, is stopped and the auxiliary equipment is restarted, a period of about several tens of seconds during which the auxiliary equipment cannot be driven occurs.

Therefore, it is one of the causes of hindering comfortable operation during train operation.

The present invention has been made in view of the above problems, and an object thereof is to provide a power conversion device for a railway vehicle capable of continuing power supply of large power to auxiliary machines even when a section passes.

The power conversion device for railways of the embodiment is provided with: a transformer, a primary winding of which is electrically connected to the overhead line via a current collector; a main power conversion device connected to a secondary winding of the transformer and connected to the drive motor; a sub-power conversion device connected to a tertiary winding of the transformer and supplying electric power to an auxiliary machine mounted on a driven object of the railway vehicle; a cutting device for electrically cutting off the transformer and the overhead line; a detector provided between the overhead wire and the cutting device, and detecting the presence or absence of the supply of power from the overhead wire; and a control unit that causes the main power conversion device to supply regenerative power of the drive motor to the sub power conversion device via the transformer in a state where the transformer and the overhead wire are electrically disconnected by the disconnection device during a period of passage of the non-power section in which at least the supply of power from the overhead wire is not performed based on an output of the detector.

Drawings

Fig. 1 is an explanatory diagram of the train and overhead line state of the embodiment.

Fig. 2 is a schematic configuration diagram of an electric power system of a locomotive according to embodiment 1.

Fig. 3 is a schematic configuration block diagram of the main power conversion device.

Fig. 4 is a detailed block diagram of a voltage signal generation unit constituting a part of the control unit.

Fig. 5 is a functional block diagram of a control unit that functions as a converter control unit.

Fig. 6 is a functional block diagram of a control unit that functions as an inverter control unit.

Fig. 7 is an explanatory diagram of the operation of embodiment 1.

Fig. 8 is an explanatory diagram of the generation of the surge voltage.

Fig. 9 is an explanatory diagram of an operation of a modification of the embodiment.

Fig. 10 is an explanatory diagram of the 1 st modification in the event of surge voltage generation.

Fig. 11 is a detailed block diagram of a voltage signal generation unit that constitutes a part of the control unit in embodiment 2.

Fig. 12 is a detailed block diagram of a control unit that functions as a converter control unit in embodiment 2.

Fig. 13 is an explanatory diagram of the operation of embodiment 2.

Fig. 14 is an explanatory diagram of the operation of embodiment 3.

Detailed Description

Next, preferred embodiments will be described with reference to the drawings.

The train 100 includes an electric locomotive (railway vehicle) 101 and a passenger car (or truck) 102 towed by the electric locomotive 101 (or propelled from behind).

Here, the electric locomotive 101 includes a pantograph 12 supplied with ac power from an overhead wire (return wire) 11 and a wheel 14 grounded via a line 13.

The overhead wire 11 includes two

overhead wires

11A and 11B having different power supply systems, and a section (section) 11X for switching the overhead wires (no-power section [ non-power-on section ]) is provided between the two

overhead wires

11A and 11B.

In the above configuration, the electric locomotive 101 includes the vehicle control device 21, and the vehicle control device 21 transmits and receives information such as a control signal from a ground equipment via the ground machine ET provided on the line 13 side and the on-board TT provided on the electric locomotive 101, and controls the entire electric locomotive 101 by referring to the acquired information. Then, the ground facility gives notice to the effect that the section 11X is reached (section arrival notice) before the section 11X is reached via the ground machine ET and the on-board TT.

[1] Embodiment 1

As shown in fig. 2, in an electric locomotive 101 according to the embodiment, a disconnector 15 and a primary winding (primary coil) 16A of a transformer 16 are connected in series between a pantograph 12 supplied with ac power from an overhead wire (return wire) 11 and a wheel 14 grounded via a line 13.

A plurality of (N systems in fig. 2, N being an integer of 2 or more) secondary windings (secondary coils) 16B of the transformer 16 are connected to a driving motor 18 via main power conversion devices (CI in fig. 2) 17-1 to 17-N, respectively. In the present embodiment, the motor 18 can be used as an electric power source for supplying regenerative electric power as a generator during the coasting operation.

In the following description, the main power conversion devices 17 are described as the main power conversion devices 17 when there is no need to identify the main power conversion devices 17-1 to 17-N, respectively.

Further, sub power conversion devices 19A to 19D corresponding to each of the plurality of (4-line in fig. 2) tertiary windings (tertiary coils) 16C of transformer 16 are connected. Here, sub-power conversion device 19A and sub-power conversion device 19C (each shown as an APU in the drawing) supply electric power to auxiliary equipment (in-vehicle electrical equipment) 20A and auxiliary equipment 20C mounted on electric locomotive 101. Sub-power conversion device 19B and sub-power conversion device 19D (shown as LGU in the figure) supply electric power to auxiliary equipment (on-vehicle electrical equipment) 20B and auxiliary equipment 20D mounted on passenger car 102.

A voltage detector (PT) 27 is provided between the pantograph 12 and the disconnector 15, and the voltage detector 27 detects a trolley voltage and outputs the detected trolley voltage to a control unit 23 described later. Here, the voltage detector 27 functions as a detector that detects the presence or absence of the supply of electric power from the overhead wire 11.

In the above configuration, the cutter 15 is controlled by the vehicle control device 21.

Under the control of the vehicle control device 21, the control unit 23 controls the main power conversion device 17 and the sub-power conversion devices 19A to 19D.

Further, a current sensor 24B for detecting a current flowing through each secondary winding 16B is provided for each secondary winding 16B. Similarly, a current sensor 24C for detecting a current flowing through each tertiary winding 16C is provided for each tertiary winding 16C.

The main power conversion device 17 includes, in rough distinction: a Converter (CNV)31 that converts ac power input from the transformer 16 into dc power in accordance with a converter PWM control signal PWM1 during a normal operation, and converts dc power input from an inverter 32, which will be described later, into ac power in accordance with a converter PWM control signal PWM1 during a regenerative power supply operation, and supplies the ac power to the transformer 16; an Inverter (INV)32 that converts dc power input from the converter 31 into three-phase ac power and supplies the three-phase ac power to the motor 18 in accordance with an inverter PWM control signal PWM2, and converts regenerative power (ac power) of the motor 18 into dc power and supplies the dc power to the converter 31 in accordance with an inverter PWM control signal PWM2 during a normal operation; and a dc voltage sensor 33 that detects a voltage of the dc power input/output between the converter 31 and the inverter 32.

In this case, the voltage signal generating unit 40 generates and outputs a voltage signal Vsv having the same phase and the same voltage (effective voltage) as the ac power input from the overhead wire 11 via the pantograph during normal traveling, and generates and outputs a voltage signal Vsv having the same phase and the same voltage (effective voltage) as the ac power input immediately before entering the section 11X as a virtual overhead wire voltage signal when the overhead wire voltage disappears due to traveling in the section (non-electric section) 11X.

The voltage signal generation unit 40 includes: a power failure detection unit 41 that determines that no power is supplied from the overhead wire 11 and outputs a power failure detection signal at "H" level ("1") when the overhead wire voltage detected by the voltage detector 27 is not detected for a predetermined threshold time or longer; a power supply phase detection unit 42 that detects the phase of the ac power supplied from the overhead wire 11 based on the overhead wire voltage (the variation in the instantaneous voltage value) detected by the voltage detector 27; a power supply voltage calculation unit 43 that calculates an effective voltage of the ac power supplied from the overhead wire 11 based on the overhead wire voltage detected by the voltage detector 27; a subtractor 44 for calculating a phase difference between the phase detected by the power phase detector 42 and a phase of a virtual overhead line voltage phase signal to be described later; a limiter 45 that limits the phase difference, which is the output of the subtractor 44, within a predetermined range; and an adder 46 for adding the output of the limiter 45 to a virtual overhead line voltage phase signal θ v output from a virtual overhead line voltage generating unit 51 described later.

The subtractor 44, the limiter 45, and the adder 46 constitute a phase change rate limiter by a combination thereof, and have a function of gradually bringing the value of the virtual overhead line voltage phase signal θ v close to the output of the power supply phase detecting unit 42. The set value of the voltage change rate limiter is set to a value (for example, 180 degrees/s) that can be followed by the auxiliary device controlled without abnormality using the voltage signal Vsv. For example, when the set value of the phase change rate limiter is set to 180 degrees/s, the limit value of the limiter 45 may be set to 0.18 degrees (180 degrees/1000 ms) when the processing of the voltage signal generation unit 40 is executed in a 1ms cycle in a program or the like executed on a microcomputer.

Further, the voltage signal generating unit 40 includes: a subtractor 47 for calculating a voltage difference between the effective voltage calculated by the power supply voltage calculation unit 43 and a virtual overhead line voltage value signal Vv described later; a limiter 48 that limits a voltage difference, which is an output of the subtractor 47, within a predetermined range (for example, within 360 degrees); and an adder 49 that adds the output of the limiter 48 to the output of the power supply voltage calculation unit 43.

The subtractor 47, the limiter 48, and the adder 49 constitute a voltage change rate limiter by a combination thereof, and have a function of gradually bringing the value of the virtual overhead line voltage value signal Vv closer to the output of the power supply voltage detection unit 43. The set value of the voltage change rate limiter is set to a value (for example, 200V/s) that can be followed by the auxiliary device controlled without abnormality using the voltage signal Vsv. For example, when the set value of the voltage change rate limiter is set to 200V/s, the limit value of the limiter 45 may be set to 0.2V (200V/1000 ms) when the processing of the voltage signal generation unit 40 is executed in a 1ms cycle as a program or the like executed on a microcomputer.

The voltage signal generating unit 40 further includes a virtual overhead line voltage generating unit 51, and the virtual overhead line voltage generating unit 51 receives the output of the adder 46 via one terminal T11 of the changeover switch 50, receives the output of the adder 49 via one terminal T21 of the changeover switch 52, and outputs a virtual overhead line voltage value signal Vv, a virtual overhead line voltage phase signal θ v, and an overhead line voltage signal Vsv.

Here, the virtual overhead wire voltage generating unit 51 is configured as a program executed on a microcomputer that inputs control as a power source phase value and a power source voltage value (effective value), for example, and in the virtual overhead wire voltage generating unit 51, the virtual overhead wire voltage value signal Vv is equal to the effective voltage value of the ac power supplied from the overhead wire 11 calculated by the power source voltage calculating unit 43 while the power failure detecting unit 41 determines that power is supplied from the overhead wire 11. In the virtual overhead wire voltage generating unit 51, while the power failure detecting unit 41 determines that power is supplied from the overhead wire 11, the virtual overhead wire voltage phase signal θ v has a value equal to the phase value of the ac power supplied from the overhead wire 11.

Therefore, in the virtual overhead wire voltage generating unit 51, the overhead wire voltage signal Vsv output while the power failure detecting unit 41 determines that power is supplied from the overhead wire 11 has a value equal to the effective voltage value of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43.

In other words, the overhead line voltage detected by the voltage detector 27 is directly output as the overhead line voltage signal Vsv, equivalent to the case where the voltage signal generating unit 40 does not perform an effective operation.

In the virtual overhead wire voltage generation unit 51, while the power failure detection unit 41 determines that no power is supplied from the overhead wire 11, the virtual overhead wire voltage value signal Vv continues to output the virtual overhead wire voltage value signal Vv immediately before the power failure detection unit 41 determines that no power is supplied from the overhead wire 11, and the virtual overhead wire voltage phase signal θ v continues to output the virtual overhead wire voltage phase signal θ v immediately before the power failure detection unit 41 determines that no power is supplied from the overhead wire 11.

Therefore, in the virtual overhead wire voltage generating unit 51, while the power failure detecting unit 41 determines that no power is supplied from the overhead wire 11, that is, while the section passes, the output of the overhead wire voltage signal Vsv continues to be equal to the actual voltage value of the ac power supplied from the overhead wire 11 immediately before the power failure detecting unit 41 determines that no power is supplied from the overhead wire 11.

Hereinafter, a period from the start of a period of a regeneration preparation operation described later to the time when the electric locomotive 101 supplies regenerative electric power to the section 11X, which is a non-electric section of the auxiliary machines 20A to 20D, is referred to as a regeneration processing period, and a period other than the regeneration processing period is referred to as a non-regeneration processing period.

In the above configuration, the virtual overhead line voltage generating unit 51 generates the virtual overhead line voltage phase signal θ v having the same phase as the phase of the ac power supplied from the overhead line 11 and output from the power supply phase detecting unit 42 during the non-regenerative processing, and outputs the generated signal to the subtractor 44 and the other terminal T12 of the changeover switch 50.

Similarly, during the non-regeneration processing period, the virtual overhead wire voltage generation unit 51 outputs the virtual overhead wire voltage value signal Vv equal to 0 to the subtractor 47 and the other terminal T22 of the changeover switch 52.

As a result, the output of the adder 46 and the output of the adder 49 are input to the virtual overhead line voltage generating unit 51 during the ineffective regeneration processing period. Then, the virtual overhead line voltage generating unit 51 outputs the overhead line voltage signal Vsv that does not actually affect the control (that is, is effectively zero) based on the outputs of the adder 46 and the adder 49.

At this time, when the limiter 45 and the limiter 48 are not actually operated, the virtual overhead line voltage phase signal θ v and the virtual overhead line voltage value signal Vv output by the virtual overhead line voltage generating unit 51 have values equal to the phase of the ac power supplied from the overhead line 11 detected by the power supply phase detecting unit 42 and the actual voltage of the ac power supplied from the overhead line 11 calculated by the power supply voltage calculating unit 43, respectively.

When the virtual overhead line voltage generator 51 passes through the section 11X (during the period of no power supply: during power outage), the selector switch 50 is switched to the terminal T12 side and the selector switch 52 is switched to the terminal T22 side in response to the power outage detection signal. Therefore, the virtual overhead line voltage phase signal θ v and the virtual overhead line voltage value signal Vv output by the virtual overhead line voltage generating unit 51 are input thereto.

As a result, the overhead line voltage signal Vsv having: a phase corresponding to the same phase as the phase of the ac power supplied from the overhead wire 11 that was output by the power supply phase detection unit 42 and that was input immediately before the power failure detection unit 41 determined that no power was supplied from the overhead wire 11; and the same voltage as the effective voltage of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43, which has been input immediately before.

The control unit 23 includes: dc link voltage control unit 61C for converter 31 outputs a dc link voltage control signal such that the dc voltage (dc link voltage) detected by dc voltage sensor 33 becomes a voltage corresponding to dc link voltage command signal VdcRef, based on dc link voltage command signal VdcRef input from vehicle control device 21 during the non-regenerative process; and a converter current command generating unit 62 that generates and outputs a converter current command signal IsRef based on the dc link voltage control signal and the output of the power supply phase detecting unit.

Further, the control unit 23 includes: a converter current control unit 63 that outputs a converter current control signal IsRef based on an output of the current sensor 24 provided in the secondary winding 16B and the converter current command signal; an adder 64 that adds the output of the power supply voltage arithmetic unit and the output of the converter current control unit; an adder 65 that adds the overhead line voltage signal Vsv output from the virtual voltage generator to the output signal of the adder 64; and a converter PWM control unit 66 that outputs a converter PWM control signal PWM1 to the converter based on the output of the adder 65.

The control unit 23 includes: dc link voltage control unit 61I for inverter 32 outputs a dc link voltage control signal so that the dc voltage (dc link voltage) detected by dc voltage sensor 33 becomes a voltage corresponding to dc link voltage command signal VdcRef, based on dc link voltage command signal VdcRef input from vehicle control device 21 during the regeneration process; and an adding unit 71 that adds the traction force command signal to the output of the dc link voltage control unit 61I and outputs the result.

Further, the control unit 23 includes: an inverter current command generating unit 72 that generates and outputs a q-axis current command signal IqRef and a d-axis current command signal IdRef, which are inverter current command signals, based on the output of the adding unit 71; an inverter current control unit 73 that outputs an inverter current control signal based on the q-axis current command signal IqRef and the d-axis current command signal IdRef; and a PWM control unit 74 that outputs an inverter PWM control signal PWM2 to the inverter based on the output of the inverter current control unit 73.

In the above configuration, during the non-regeneration processing period, the dc link voltage control unit 61C operates, and the dc link voltage control unit 61I stops (outputs 0).

On the other hand, during the regeneration process, the dc link voltage control unit 61C stops (outputs 0), and the dc link voltage control unit 61I operates. At this time, the traction force command signal is set to 0.

Next, the operation of embodiment 1 will be described.

Fig. 7 is an explanatory diagram of the operation of embodiment 1.

At time t1, before the timing at which the arrival at the section 11X is predicted from the ground equipment using the track circuit, the phase of the overhead line voltage supplied to the primary winding 16A coincides with the phase of the voltage supplied to the secondary winding 16B.

Then, at time t1, when it is predicted that zone 11X is reached based on a zone control signal from the ground equipment via floor machine ET and on-board TT (see fig. 1), converter current command signal (IsRef) and inverter current command signal (IqRef) are controlled so that the torque (motor torque) of motor 18 gradually decreases. That is, the converter current command generating unit 62 of the converter performs control so that the dc-side current (i.e., dc link current) flowing from the converter 31 to the inverter 32 gradually becomes zero.

As a result, the converter current command generating unit 62 performs control so that the dc-side current of the converter (i.e., the dc link current) becomes substantially zero at time t2, and the inverter current command generating unit 72 performs control so that the three-phase ac-side current flowing from the inverter 32 to the motor 18 becomes substantially zero at time t 2.

Then, at time t2, the control unit 23 shifts to a regeneration preparation operation to set the operation of the main power converter 17 to the regeneration operation mode. That is, at time t2, the period shifts from the non-regeneration processing period to the regeneration processing period.

Thus, the dc link voltage control unit (inverter) 61I in the operating state performs control such that the ac side current of the converter 31 flowing from the converter 31 to the transformer 16 gradually increases. The inverter current command generating unit 72 performs control so as to gradually increase a dc-side current (i.e., a dc link current) which is a regenerative current generated by the motor 18 and output to the converter 31.

Thus, even when the locomotive 101 reaches the section 11X, which is the non-energized section, the regenerative power of the motor 18 can be supplied to the sub-power conversion devices 19A to 19D via the transformer 16, and the sub-power conversion devices 19A to 19D apparently maintain the state of continuing to supply power from the overhead wire 11.

Then, at time t3 when the regeneration preparation operation is reliably completed, the disconnector 15 is brought into the open state (off state: disconnected state).

Therefore, during the period from time t3 to time t4, electric power is not supplied from the overhead wire 11 to the sub-power conversion devices 19A to 19D via the pantograph 12 and the primary winding 16A of the transformer 16, but the main power conversion device 17 supplies regenerative electric power of the motor 18 to the sub-power conversion devices 19A to 19D via the transformer 16. Therefore, sub-power conversion devices 19A to 19D continue to supply electric power to auxiliary machines 20A to 20D, and auxiliary machines 20A to 20D maintain the state of continuing operation.

On the other hand, during the period from time t3 to time t4, the power failure detection signal remains at "0" level because the voltage detector 27 is still detecting the overhead wire voltage.

Then, at time t4, when the electric locomotive 101 reaches the section 11X as the non-power section, the voltage detector 27 cannot detect the overhead line voltage, and the power outage detection signal transitions to the "1" level.

As a result, since the power failure detection signal becomes "1" level, the changeover switch 50 is switched to the terminal T12 side. Further, the changeover switch 52 is switched to the terminal T22 side. Therefore, the virtual overhead line voltage phase signal θ V and the virtual overhead line voltage value signal Vv output by the virtual overhead line voltage generating unit 51 are input thereto.

As a result, the virtual overhead line voltage generation unit 51 continuously outputs the overhead line voltage signal Vsv to the PWM control unit 66 via the adder 65, the overhead line voltage signal Vsv having: a phase corresponding to the same phase as the phase of the ac power supplied from the overhead wire 11 and outputted by the power supply phase detection unit 42 immediately before; and the same voltage as the effective voltage of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43, which has been input immediately before.

At this time, since the output of converter current control unit 63 becomes zero, the overhead line voltage signal Vsv is effectively output to PWM control unit 66. Thus, converter 31 sets the regenerative power of motor 18 output from inverter 32 to the same state (phase and voltage) as that of receiving the power supply from overhead wire 11A, and supplies the regenerative power to auxiliary machines 20A to 20D via sub-power conversion devices 19A to 19D during the period of passage of section 11X (time t4 to time t5) via secondary winding 16B and tertiary winding 16C. Therefore, the auxiliary machines 20A to 20D continue their operation.

When the electric locomotive 101 passes through the section 11X and reaches the overhead wire 11B at time t5, the voltage detector 27 detects the overhead wire voltage again, and the power failure detection signal transitions to "0" level.

At this point in time, as shown in fig. 7, the phase and voltage of the ac power supplied from the overhead wire 11B are different from those of the ac power supplied from the overhead wire 11A. Therefore, the control unit 23 continues the supply of the regenerative electric power of the motor 18 from the main power conversion device 17 to the auxiliary machines 20A to 20D.

At this time, the outputs of the power supply phase detection unit 42 and the power supply voltage calculation unit 43 are input to the virtual overhead line voltage generation unit 51 again via the adder 46 and the adder 49. Therefore, the virtual overhead line voltage generation unit 51 gradually brings the overhead line voltage signal Vsv close to the voltage waveform detected by the voltage detector 27. Then, a time point at which it is determined (i.e., can be determined) that the phase of the regenerative power, which is the ac-side power output by converter 31, is equal to the phase and the voltage of the ac power supplied from overhead wire 11B is time point t 6.

Therefore, when detecting that the overhead line voltage signal Vsv matches the voltage waveform detected by the voltage detector 27 at time t7, the control unit 23 brings the breaker 15 into the closed state (on state) again.

The converter current command generating unit 62 is controlled by the converter current command signal (IsRef) such that the current amount of the regenerative power output to the transformer 16 side gradually decreases to zero. Further, the inverter current command generating unit 72 is controlled by the inverter current command signal (IqRef, IdRef) such that the current amount of the regenerative power output to the converter 31 side gradually decreases to zero.

As a result, the converter current command generating unit 62 controls the dc-side current (i.e., the dc link current) of the converter 31 to be substantially zero at time t8 when the current based on the regenerative power of the motor 18 becomes zero. The inverter current command generating unit 72 performs control so that the dc side current of the inverter 32 becomes substantially zero at time t 8.

Then, at time t8, the control unit 23 shifts the operation of the main power converter 17 from the regenerative operation mode to the normal operation mode. That is, control unit 23 shifts to a normal operation mode in which electric power supplied from overhead wire 11 (overhead wire 11B) is supplied to sub-power conversion devices 19A to 19D via primary winding 16A and tertiary winding 16C of transformer 16, and sub-power conversion devices 19A to 19D supply electric power to corresponding auxiliary machines 20A to 20D.

As described above, according to embodiment 1, even when the electric locomotive 101 passes through the section 11X, which is a non-electric-power-section, the regenerative electric power from the driving motor 18 can be supplied to the sub-power conversion devices 19A to 19D and the auxiliary machines 20A to 20D via the inverter 32, the converter 31, the secondary winding 16B of the transformer 16, and the tertiary winding 16C, instead of the electric power supply from the overhead wire 11. Therefore, it is possible to perform comfortable operation in the section 11X without stopping the operation of the auxiliary machine, and without requiring a restoration operation of a device with large electric power such as an air conditioning device as an auxiliary machine.

[2] Modification of the embodiment

[2.1] modifications

In the circuit shown in fig. 2, when the main power converter 17 is operated in an open state (off state: cut-off state) of the breaker 15, that is, in a state where the primary winding 16A of the transformer 16 is disconnected, a large surge voltage may be generated in the primary winding 16A in association with the switching operation.

Fig. 8 is an explanatory diagram of the generation of the surge voltage.

As shown in fig. 8, when the PWM control waveform P1 is input, a large surge voltage P3 is generated with respect to the intended output voltage waveform P2.

Therefore, in the present modification, in order to suppress the surge voltage P3, the carrier frequency at the time of generating the PWM waveform is changed between the case where the disconnector 15 is in the closed state (on state) and the case where the disconnector 15 is in the open state (off state).

The following description will be made in detail.

At time t11, when the arrival section 11X is notified from the ground equipment in advance, the converter current command signal and the inverter current command signal are controlled so that the torque of the motor 18 (motor torque) gradually decreases. That is, the converter current command generating unit 62 controls the dc-side current (i.e., the dc link current) flowing from the converter 31 to the inverter 32 to gradually become zero.

As a result, the converter current command generating unit 62 performs control so that the dc-side current of the converter (i.e., the dc link current) becomes substantially zero at time t12, and the inverter current command generating unit performs control so that the three-phase ac-side current output from the inverter 32 to the motor 18 becomes substantially zero at time t 12.

Then, at time t12, the control unit 23 shifts to a regeneration preparation operation to set the operation of the main power converter 17 to the regeneration operation mode. That is, at time t12, the period shifts from the non-regeneration processing period to the regeneration processing period.

At this time, when the carrier frequency of the converter 31 is a value close to the electrical natural frequency of the transformer 16, a resonance phenomenon occurs in the transformer 16, and a voltage larger than usual may be generated. To avoid this, converter current command generating unit 62 changes the carrier frequency used in PWM control unit 66 to be higher than the normal operation (carrier frequency during regenerative operation > carrier frequency during normal operation). The dc link voltage control unit (inverter) 61I controls the ac side current of the converter 31 flowing from the converter 31 to the transformer 16 to gradually increase. The inverter current command generating unit 72 performs control so as to gradually increase a dc-side current (i.e., a dc link current) which is a regenerative current generated by the motor 18 and output to the converter 31.

When the carrier frequency of the converter 31 is a value close to the electrical natural frequency of the transformer 16 as described above, the carrier frequency at the time of the regenerative operation, which is higher than the carrier frequency at the time of the normal operation, is used, and thereby generation of a large voltage due to a resonance phenomenon occurring inside the transformer 16, that is, generation of a voltage P3 which greatly exceeds the output voltage waveform P1 of the transformer 16 as shown in fig. 8, can be suppressed.

As shown in fig. 10, even if the PWM control waveform P11 is input, the surge voltage P13 generated with respect to the target output voltage waveform P2 is suppressed.

Even when the locomotive 101 reaches the section 11X, which is a non-electric-power section, the regenerative power of the motor 18 is supplied to the sub-power conversion devices 19A to 19D via the inverter 32, the converter 31, and the transformer 16. Therefore, in sub-power conversion devices 19A to 19D, apparently, preparation for continuing to supply power from overhead wire 11 is completed.

Therefore, during the period from time t13 to time t14, electric power is not supplied from the overhead wire 11 to the sub-power conversion devices 19A to 19D via the pantograph 12 and the primary winding 16A of the transformer 16. However, main power conversion device 17 supplies regenerative electric power of motor 18 to sub-power conversion devices 19A to 19D via transformer 16. As a result, sub-power conversion devices 19A to 19D continue to supply electric power to auxiliary machines 20A to 20D, and auxiliary machines 20A to 20D maintain a state of continuous operation.

On the other hand, since the voltage detector 27 is still detecting the overhead line voltage, the power failure detection signal remains at the "0" level during the period from time t13 to time t 14.

When the electric locomotive 101 reaches the section 11X, which is the non-electric section, at time t14, the voltage detector 27 cannot detect the overhead line voltage, and the power outage detection signal transitions to the "1" level.

As a result, the virtual overhead line voltage generation unit 51 continuously outputs to the PWM control unit 66 via the adder 65 an overhead line voltage signal Vsv having: a phase corresponding to the same phase as the phase of the ac power supplied from the overhead wire 11 and outputted by the power supply phase detection unit 42 immediately before; and the same voltage as the effective voltage of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43, which has been input immediately before.

At this time, since the output of converter current control unit 63 becomes zero, the overhead line voltage signal Vsv is effectively output to PWM control unit 66. That is, converter 31 sets the regenerative power of motor 18 output from inverter 32 to the same state (phase and voltage) as that of receiving the power supply from overhead wire 11A, supplies the regenerative power to auxiliary machines 20A to 20D via sub-power conversion devices 19A to 19D during the period of passage of section 11X (time t14 to time t15) via secondary winding 16B and tertiary winding 16C, and continues the operation.

When the electric locomotive 101 passes through the section 11X and reaches the overhead wire 11B at time t15, the voltage detector 27 detects the overhead wire voltage again, and the power failure detection signal transitions to "0" level.

At this point in time, as shown in fig. 10, the phase and voltage of the ac power supplied from the overhead wire 11B are different from those of the ac power supplied from the overhead wire 11A. Therefore, the control unit 23 continues the supply of the regenerative electric power of the motor 18 from the main power conversion device 17 to the auxiliary machines 20A to 20D.

At this time, the outputs of the power supply phase detection unit and the power supply voltage calculation unit are input to the virtual overhead line voltage generation unit 51 again via the adder 46 and the adder 49, and the overhead line voltage signal Vsv gradually approaches the voltage waveform detected by the voltage detector 27. Then, a time point at which it is determined (i.e., can be determined) that the phase of the regenerative power, which is the ac-side power output by converter 31, is equal to the phase and the voltage of the ac power supplied from overhead wire 11B is time point t 16.

Therefore, when detecting that the overhead wire voltage signal Vsv and the voltage waveform detected by the voltage detector 27 are effectively matched at time t17, the control unit 23 brings the disconnector 15 into the closed state (on state) again.

The converter current command generating unit 62 controls the current amount of the regenerative power output to the transformer 16 side to gradually decrease and become zero by the converter current command signal, and the inverter current command generating unit 72 controls the current amount of the regenerative power output to the converter 31 side to gradually decrease and become zero by the INV current command signal.

As a result, the converter current command generating unit 62 controls the output current of the converter 31 (i.e., the dc link current) to be substantially zero at time t8 when the current based on the regenerative power of the motor 18 becomes zero, and the inverter current command generating unit 72 controls the output current of the inverter 32 to be substantially zero at time t 18.

Then, at time t18, the control unit 23 shifts the operation of the main power converter 17 from the regenerative operation mode to the normal operation mode.

At this stage, since the disconnector 15 is already in the closed state (on state), the carrier frequency used in the PWM control unit 66 and the carrier frequency used in the PWM control unit 74 are again lowered to the carrier frequency at the time of normal operation, and the operation of the main power conversion device 17 is shifted from the regenerative operation mode to the normal operation mode in which the electric power supplied from the overhead wire 11 (the overhead wire 11B) is supplied to the sub-power conversion devices 19A to 19D via the primary winding 16A and the tertiary winding 16C of the transformer 16, and the sub-power conversion devices 19A to 19D supply the electric power to the corresponding auxiliary machines 20A to 20D.

As described above, according to modification 1 of the present embodiment, in addition to the effects of the embodiment, it is possible to suppress the generation of surge voltage and to operate the auxiliary device more stably.

[2.2] other modifications

In the above description, the two main power conversion devices have been described as being mounted on the same electric locomotive 101, but may be configured to be mounted on a plurality of electric locomotives 101.

Further, the same applies to the case where 3 or more main power conversion devices are mounted.

Further, when a plurality of main power conversion devices are mounted, the regenerative electric power may be supplied to the auxiliary machine by at least one of the plurality of main power conversion devices.

Further, when a speed detection unit that detects a traveling speed of the railway vehicle is provided and the traveling speed of the railway vehicle when the non-electric section passes through is lower than a predetermined traveling speed, the supply of the regenerative power of the drive motor to the sub-power conversion device via the transformer may be prohibited. This prevents the speed of the railway vehicle from being lowered more than necessary in the non-electric section, which is the coasting operation state.

[3] Embodiment 2

The present embodiment is different from embodiment 1 in that, when a wheel slip is detected during a regenerative operation in the non-electric zone, the regenerative operation is reliably performed by suppressing the slip.

In the case of performing the control of embodiment 1, the vehicle is braked by the regenerative operation, and when the power consumption of the auxiliary power supply, the passenger car power supply, and the like becomes high and the braking force becomes strong, or the adhesion coefficient between the rail and the wheel becomes small, the vehicle may be brought into a coasting state.

When the vehicle is in the coasting state, not only the track and the wheels are damaged, but also required regenerative power (regenerative energy) cannot be obtained.

Therefore, in embodiment 2, the coasting state is suppressed, and the regenerative operation is performed efficiently.

The following description will be specifically made.

In fig. 11, the same reference numerals are given to the same parts as those in fig. 4.

The voltage signal generator 40 according to embodiment 2 is different from the voltage signal generator 40 according to embodiment 1 in that it includes: a coasting detection unit 71 that detects whether or not a coasting state is achieved based on the output of the motor 18; and a power control unit 72 that restricts the overhead line voltage signal Vsv when the coasting detection unit 71 detects the coasting state, and outputs a coasting-time overhead line voltage signal Vsv' (< Vsv).

Fig. 12 is different from fig. 5 in that an adder 65 adds the overhead line voltage signal Vsv or the coast-time overhead line voltage signal Vsv' output from the power control unit 72 to the output signal of the adder 64.

Next, the operation of embodiment 2 will be described.

In the following description, for the sake of easy understanding, two main power converters (N: 2) are provided, that is, the main power converters 17-1 to 17-2 are provided, and only the operation during the period (time t3 to time t7 in fig. 2) in which the disconnector 15 is in the open state (off state: disconnected state) will be described.

In embodiment 2, a case will be described in which a skid is detected in the wheels 14 corresponding to the motor 18-1 on the main power conversion device 17-1 side.

Fig. 13 is an explanatory diagram of the operation of embodiment 2.

When the coast detection unit 71 corresponding to the motor 18-1 of the main power conversion device 17-1 detects coasting while the disconnector 15 is in the open state (off state: shut-off state), as shown at time t21, the power control unit 72 of the main power conversion device 17-1 limits the virtual overhead line voltage Vsv and outputs the coasting virtual overhead line voltage Vsv' (< Vsv) to the adder 65 of the main power conversion device 17-1.

Thus, the adder 65 adds the coasting virtual overhead line voltage Vsv' output from the power control unit 72 to the output signal of the adder 64 of the main power conversion device 17-1 at the main power conversion device 17-1.

As a result, at time t21, the virtual overhead line voltage generation unit 51 stops outputting the overhead line voltage signal Vsv having: a phase corresponding to the same phase as the phase of the ac power supplied from the overhead wire 11 and outputted by the power supply phase detection unit 42 immediately before; and the same voltage as the effective voltage of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43, which has been input immediately before.

As a result, the regenerative power of the converter 31(CNV1 in fig. 13) on the main power conversion device 17-1 side decreases, and the regenerative output of the inverter (INV 1 in fig. 13) on the power conversion device 17-1 side decreases with the decrease in the regenerative power, so that the torque of the motor 18 decreases, and the motor operates so as to converge the coasting state (so as to cause coasting once again).

On the other hand, the regenerative electric power of the converter 31(CNV 2 in fig. 13) on the main power conversion device 17-2 side is increased by an amount that complements the decrease in the regenerative electric power of the converter 31(CNV1) on the main power conversion device 17-1 side. As the regenerative power increases, the regenerative output of the inverter (referred to as INV2 in fig. 13) on the power conversion device 17-2 side increases.

Thus, the pair of converters 31 on the main power conversion device 17-1 side and the main power conversion device 17-2 side supply the regenerative electric power of the motor 18 output from the pair of inverters 32 on the main power conversion device 17-1 side and the main power conversion device 17-2 side to the same total (phase and voltage) as the state of receiving the electric power supply from the overhead wire 11A, to the auxiliary machines 20A to 20D via the sub-power conversion devices 19A to 19D during the passage of the section 11X (time t4 to time t5) via the secondary winding 16B and the tertiary winding 16C. Therefore, the auxiliary machines 20A to 20D continue their operation.

Then, as shown at time t22, the coasting state is canceled, and the power control unit 72 on the main power conversion device 17-1 side outputs the virtual power line voltage Vsv to the adder 65 on the power conversion device 17-1 side again instead of the virtual power line voltage Vsv', so that the main power conversion device 17-1 and the main power conversion device 17-2 return to the same state as before time t21 again.

As described above, according to embodiment 2, since the electric power supply to the auxiliary machines 20A to 20D can be continued while suppressing coasting in the electric power conversion device in the driving state, it is possible to obtain required regenerative electric power (regenerative energy) without damaging the rails and wheels.

In the above description, the number of the main power conversion devices 17 is two, but the same applies even if the number is 3 or more.

[4] Embodiment 3

Next, referring again to fig. 2, a power system of a locomotive according to embodiment 3 will be described.

The present embodiment differs from embodiment 2 in that the main power conversion device in the standby state (non-driving state) is driven to suppress the coasting state when the wheel corresponding to the main power conversion device in the driving state enters the coasting state.

In the following description, for the sake of simplicity, three main power converters (N is 3), that is, the main power converters 17-1 to 17-3 are provided, and only the operation during the period (time t3 to time t7 in fig. 2) in which the disconnector 15 is in the open state (off state: disconnected state) will be described.

In embodiment 3, two main power conversion devices 17-1 and 17-2 (see fig. 2) are set to a driving state, and one main power conversion device 17-3 is set to a standby state, and a case where a skid is detected in the wheel 14 corresponding to the motor 18-1 on the main power conversion device 17-1 side will be described.

Here, it is assumed that the main power conversion device 17-3 is in a standby state in which the power conversion operation is not performed when the main power conversion device 17-1 and the main power conversion device 17-2 are normally operated without being affected by the coasting state. The main power conversion device that sets one or two of the three main power conversion devices in the standby state is arbitrary, and for example, the main power conversion devices can be set in the standby state in order to make the frequency of use uniform.

Next, the operation of embodiment 3 will be described.

In the following description, for the sake of easy understanding, only the operation during the period (time t3 to time t7 in fig. 2) in which the disconnector 15 is in the open state (off state: disconnected state) will be described. In embodiment 3, it is assumed that, in the initial state, two main power converters 17-1 and 17-2 (see fig. 2) operate as a pair as one main power converter.

Fig. 14 is an explanatory diagram of the operation of embodiment 3.

When the coast detection unit 71 corresponding to the motor 18-1 of the main power conversion device 17-1 detects coasting while the disconnector 15 is in the open state (off state: shut-off state), as shown at time t31, the power control unit 72 of the main power conversion device 17-1 limits the virtual overhead line voltage Vsv and outputs the coasting virtual overhead line voltage Vsv' (< Vsv) to the adder 65 of the main power conversion device 17-1.

Thus, at time t31, the virtual overhead wire voltage generating unit 51 stops outputting the voltage overhead wire voltage signal Vsv having the same phase as the phase of the ac power supplied from the overhead wire 11 that has been input and output by the power supply phase detecting unit 42 immediately before and the same effective voltage as the ac power supplied from the overhead wire 11 that has been input and calculated by the power supply voltage calculating unit 43 immediately before, and outputs the overhead wire voltage signal Vsv' having a voltage lower than the voltage overhead wire voltage signal Vsv to the PWM control unit 66 via the adder 65.

As a result, the regenerative power of the converter 31(CNV1 in fig. 14) on the main power conversion device 17-1 side decreases, and the regenerative output of the inverter (INV 1 in fig. 14) on the power conversion device 17-1 side decreases with the decrease in the regenerative power, so that the torque of the motor 18 decreases and the operation converges to the coasting state.

On the other hand, the regenerative electric power of the converter 31(CNV 2 in fig. 13) on the main power conversion device 17-2 side is increased so as to compensate for the decrease in the regenerative electric power of the converter 31(CNV1) on the main power conversion device 17-1 side. As the regenerative power increases, the regenerative output of the inverter (referred to as INV2 in fig. 13) on the power conversion device 17-2 side increases.

However, as shown at time t32, when the coasting is detected by the coasting detection unit 71 corresponding to the motor 18-1 on the main power conversion device 17-1 side and further the coasting is detected by the coasting detection unit 71 corresponding to the motor 18-1 on the main power conversion device 17-2 side, the power control unit 72 on the main power conversion device 17-2 side limits the virtual wire voltage Vsv and outputs the coasting virtual wire voltage Vsv' (< Vsv) to the adder 65 on the main power conversion device 17-2 side.

Thus, the adder 65 also on the main power conversion device 17-2 side adds the coasting virtual overhead line voltage Vsv' output from the power control unit 72 to the output signal of the adder 64 on the main power conversion device 17-2 side.

Thus, at time t32, the virtual overhead line voltage generation unit 51 stops outputting the overhead line voltage signal Vsv having: a phase corresponding to the same phase as the phase of the ac power supplied from the overhead wire 11 and outputted by the power supply phase detection unit 42 immediately before; and the same voltage as the effective voltage of the ac power supplied from the overhead wire 11 calculated by the power supply voltage calculating unit 43, which has been input immediately before.

As a result, the regenerative power of the converter 31(CNV 2 in fig. 14) on the main power conversion device 17-2 side decreases, and the regenerative output of the inverter (INV 2 in fig. 14) on the power conversion device 17-2 side decreases with the decrease in the regenerative power, so that the torque of the motor 18 decreases, and the operation converges to the coasting state.

Then, the output of the regenerative electric power is started to supplement the amount of decrease in the regenerative electric power of the converter 31(CNV1) on the main power conversion device 17-1 side and the amount of decrease in the regenerative electric power of the converter 31(CNV1) on the main power conversion device 17-1 side with respect to the regenerative electric power of the converter 31(CNV 3) on the main power conversion device 17-3 side, and the regenerative electric power is increased. The increase in the regenerative power increases the regenerative output of the inverter (referred to as INV3 in fig. 14) on the power conversion device 17-3 side.

Thus, the three converters 31 of the main power conversion device 17-1, the main power conversion device 17-2, and the main power conversion device 17-3 supply the regenerative electric powers of the motors 18 output from the three inverters 32 of the main power conversion device 17-1, the main power conversion device 17-2, and the main power conversion device 17-3 to the auxiliary machines 20A to 20D via the sub power conversion devices 19A to 19D during the period (time t4 to time t5) in which the secondary winding 16B and the tertiary winding 16C pass the section 11X, with the total regenerative electric powers being equal to the state (phase and voltage) supplied with electric power from the overhead wire 11A in total. Therefore, the auxiliary machines 20A to 20D continue their operation.

Then, as shown at time t33, when the coasting state of the wheel corresponding to the motor 18-1 on the main power conversion device 17-1 side is canceled, the power control unit 72 on the main power conversion device 17-1 side outputs the rack line voltage signal Vsv to the adder 65 on the power conversion device 17-1 side again instead of the rack line voltage signal Vsv', so that the regenerative power of the converter 31 (shown as CNV3 in fig. 14) on the main power conversion device 17-3 side is reduced by an amount sufficient to compensate for the decrease in the regenerative power of the converter 31(CNV1) on the main power conversion device 17-1 side. As the regenerative power decreases, the regenerative output of the inverter (referred to as INV3 in fig. 14) on the power conversion device 17-3 side also decreases.

Thus, the three converters 31 of the main power conversion device 17-1, the main power conversion device 17-2, and the main power conversion device 17-3 supply the regenerative electric powers of the motors 18 output from the three inverters 32 of the main power conversion device 17-1, the main power conversion device 17-2, and the main power conversion device 17-3 to the auxiliary machines 20A to 20D via the sub power conversion devices 19A to 19D during the period (time t4 to time t5) in which the secondary winding 16B and the tertiary winding 16C receive the electric power supply from the overhead wire 11A, in a total amount equal to the electric power supply received from the overhead wire 11A. Therefore, the auxiliary machines 20A to 20D continue their operation.

Then, as shown at time t34, when the coasting state of the wheel corresponding to the motor 18-1 on the main power conversion device 17-1 side is canceled, the power control unit 72 on the main power conversion device 17-3 side outputs the rack line voltage signal Vsv to the adder 65 on the power conversion device 17-3 side again instead of the rack line voltage signal Vsv', so that the main power conversion device 17-1, the main power conversion device 17-2, and the main power conversion device 17-1 operate so as to equalize the regenerative power supply ratio.

This is because, when the state is returned to the same state as before time t31 again, the load may become excessive and the state may be shifted to the slipping state again only by the pair of main power conversion devices, and this is avoided in the non-power section.

As described above, according to embodiment 3, since the electric power supply to the auxiliary machines 20A to 20D can be continued while suppressing coasting in the railway vehicle provided with 3 main power conversion devices 17, it is possible to obtain necessary regenerative electric power (regenerative energy) without damaging the rails and wheels and to suppress the transition to the coasting state again in the same non-electric section.

In the above description, the number of the main power converters is 3, but even in the case of a railway vehicle including two main power converters, when a wheel corresponding to one of the main power converters is detected to slip while only one of the main power converters is being driven, the other main power converter in the non-driving state is driven to suppress the slip and continue the power supply to the auxiliary machine.

Similarly, the same applies to 4 or more main power converters 17. In this case, when there are a plurality of main power conversion devices 17 in the non-driving state, it is arbitrary to which one or more main power conversion devices 17 are to be shifted to the driving state.

In the above description, the case where the one primary winding 16A of the one transformer 16 is electrically connected to the ground side of the disconnector has been described, but the present invention can be similarly applied to the case where a plurality of primary windings of a plurality of transformers are electrically connected to the ground side of the disconnector.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims

1. A power conversion device for a railway vehicle is provided with:

a transformer, a primary winding of which is electrically connected to the overhead line via a current collector;

a main power conversion device connected to the secondary winding of the transformer and connected to a drive motor;

a sub-power conversion device connected to the tertiary winding of the transformer and configured to supply electric power to an auxiliary device mounted on a driven object of the railway vehicle;

a cutting device for electrically cutting off the transformer from the overhead wire;

a detector provided between the overhead wire and the disconnecting device, the detector detecting presence or absence of supply of electric power from the overhead wire; and

a control unit that causes the main power conversion device to supply regenerative power of the drive motor to the sub power conversion device via the transformer while the transformer is electrically disconnected from the overhead wire by the disconnection device during a period of passage of a dead zone in which at least the supply of power from the overhead wire is not performed based on an output of the detector,

the main power conversion device is provided with a converter for performing power conversion by PWM control,

the control unit sets a carrier frequency in the PWM control during the shutdown of the shutdown device to be higher than a carrier frequency in the PWM control during the non-shutdown of the shutdown device, in order to suppress a resonance phenomenon in the transformer caused by an electrical natural frequency of the transformer and a carrier frequency of the converter.

2. The power conversion apparatus for railway vehicles according to claim 1,

the main power transformation device is provided with a plurality of power transformation devices,

at least one of the plurality of main power converters supplies the regenerative electric power.

3. The power conversion apparatus for railway vehicles according to claim 1,

the power conversion device for a railway vehicle is provided with a plurality of the transformers,

the primary windings of the plurality of transformers are connected to the overhead wire via the cutoff device.

4. The power conversion apparatus for railway vehicles according to claim 1,

the power conversion device for a railway vehicle is provided with a speed detection unit for detecting the traveling speed of the railway vehicle,

the control unit prohibits the supply of the regenerative power of the drive motor to the sub-power conversion device via the transformer when a traveling speed of the railway vehicle passing through the non-electric section is less than a predetermined traveling speed.

5. A power conversion device for a railway vehicle is provided with:

a plurality of main power conversion devices connected to the secondary windings of the transformers and to drive motors for driving wheels, respectively;

a plurality of skid detection units provided in correspondence with the plurality of main power conversion devices, for detecting a skid state of the wheels;

a sub-power conversion device connected to the tertiary winding of the transformer and supplying electric power to an auxiliary machine or an auxiliary group mounted on a railway vehicle to be driven;

a cutting device for electrically cutting off the transformer from the overhead wire; and

a control unit that causes the main power conversion device to supply regenerative power of the drive motor to the sub power conversion device via the transformer in a state where the transformer and the overhead line are electrically disconnected from each other by the disconnection device when passing through a non-power section provided between the overhead line and another overhead line,

the control section is set such that the regenerative power of the main power conversion apparatus for which coasting is detected by the coasting detection section is lower than that before coasting detection,

the other main power conversion device for which coasting is not detected by the coasting detection unit is supplied by adding an amount corresponding to the decrease in the regenerative power.

6. The power conversion apparatus for railway vehicles according to claim 5,

the main power conversion device includes a plurality of main power conversion devices, and at least 1 of the main power conversion devices is provided as a spare main power conversion device in which the supply of the regenerative power to the sub power conversion device is stopped in a state where all of the coasting detection units corresponding to the other main power conversion devices do not detect the coasting state.

7. The power conversion apparatus for railway vehicles according to claim 6,

the main power conversion device continues to supply the regenerative power to the sub-power conversion device at least until the main power conversion device passes through the dead zone after the coasting state is detected by all of the coasting detection units corresponding to the other main power conversion devices.