Power conversion system

Patent metadata

Field	Value
Publication number	US-10525838-B2
Application number	US-201715623818-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Jun 16, 2016
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A power conversion system includes a transformer, a power conversion device for travel, a power conversion device for auxiliary power sources, and an electrical storage device. The power conversion device for auxiliary power sources includes a first AC to DC conversion unit, a power conversion unit for AC loads, and a power conversion unit for DC loads. The power conversion unit for AC loads converts DC power into AC power and supplies it to an AC load. The power conversion unit for DC loads converts DC power produced through conversion by the first AC to DC conversion unit into DC power and supplies it to a DC load. The electrical storage device is connected to power lines connecting DC power output terminals of the first AC to DC conversion unit and DC power input terminals of both the power conversion units for AC and DC loads. When power supplied from a tertiary winding of the transformer to the first AC to DC conversion unit is reduced, the electrical storage device discharges power corresponding to the power reduction.

First claim

What is claimed is:

1. A power conversion system comprising:
a transformer configured to step down power from an overhead wire;
a power conversion device for travel connected between a secondary winding of the transformer and a travel motor configured to allow travel of an electric vehicle, the power conversion device for travel being configured to convert first alternating current power supplied via the secondary winding of the transformer into power for travel for driving the travel motor;
a first alternating current to direct current conversion unit configured to convert second alternating current power supplied via a tertiary winding of the transformer into direct current power,
a power conversion unit for alternating current loads connected between the first alternating current to direct current conversion unit and an alternating current load which is electrically isolated from the travel motor, the power conversion unit for alternating current loads being configured to convert the direct current power produced through conversion by the first alternating current to direct current conversion unit into alternating current power for driving an alternating current load mounted in the electric vehicle and to supply the alternating current power to the alternating current load,
a power conversion unit for direct current loads connected between the first alternating current to direct current conversion unit and a direct current load which is electrically isolated from the travel motor, the power conversion unit for direct current loads configured to convert the direct current power produced through conversion by the first alternating current to direct current conversion unit into direct current power for driving a direct current load mounted in the electric vehicle and to supply the direct current power to the direct current load; and
an electrical storage device connected to a first pair of power lines which connects a direct current power output terminal of the first alternating current to direct current conversion unit and a direct current power input terminal of the power conversion unit for alternating current loads, the electrical storage device being connected to a second paid of power lines which connects the direct current power output terminal of the first alternating current to direct current conversion unit and the power conversion unit for direct current loads;
a charging circuit for travel connected between the power conversion device for travel and the secondary winding of the transformer; and
a charging circuit connected to a power line which connects the charging circuit for travel and the power conversion device for travel, the charging circuit being configured to supply a discharge power from the electrical storage device to the power conversion device for travel when there occurs reduction of a power which is supplied to the power conversion device for travel which is configured to supply a power from the secondary winding of the transformer to the travel motor.

2. The power conversion system according to claim 1 , wherein the first alternating current to direct current conversion unit includes:
a switching circuit including a plurality of switching elements and diodes connected in antiparallel with the plurality of switching elements; and
a control unit configured to switch the plurality of switching elements between a conductive state and a non-conductive state to convert the second alternating current power into direct current power.

3. The power conversion system according to claim 1 , wherein the electrical storage device is connected to a power line connecting the power conversion device for travel and the secondary winding of the transformer,
a contactor configured to be switched between a power cut-off state and a power supply state is provided in a middle of the power line connecting the power conversion device for travel and the secondary winding of the transformer, and
the electrical storage device is configured to supply discharge power to the power conversion device for travel when the contactor has been switched to the power supply state.

4. The power conversion system according to claim 3 , further comprising a manipulation portion configured to receive a manipulation of causing the electric vehicle to travel with power discharged by the electrical storage device when the electric vehicle is in an emergency,
wherein the contactor is configured to be switched from the power cut-off state to the power supply state upon receiving the manipulation by the manipulation portion.

5. The power conversion system according to claim 4 , further comprising a travel power control unit configured to switch a travel mode between a first travel mode in which the travel power control unit drives switching elements in the power conversion device for travel on the basis of a carrier signal having a predetermined frequency to cause the travel motor to generate a travel torque in a normal situation in which the electric vehicle is not in an emergency, and a second travel mode in which the travel power control unit drives the switching elements on the basis of a carrier signal having a lower frequency than the predetermined frequency to cause the travel motor to generate a travel torque,
wherein the travel power control unit is configured to switch the travel mode to the second travel mode when the electric vehicle is in an emergency.

6. The power conversion system according to claim 1 , wherein the power conversion device for travel includes a second alternating current to direct current conversion unit configured to convert the first alternating current power into direct current power and a direct current to alternating current conversion unit configured to convert the direct current power produced through conversion by the second alternating current to direct current conversion unit into the power for travel,
the electrical storage device is connected to a power line connecting the second alternating current to direct current conversion unit and the direct current to alternating current conversion unit,
a contactor configured to be switched between a power cut-off state and a power supply state is provided in a middle of the power line connecting the second alternating current to direct current conversion unit and the direct current to alternating current conversion unit, and
the electrical storage device is configured to supply discharge power to the direct current to alternating current conversion unit when the contactor has been switched to the power supply state.

Assignees

• Tokai Ryokaku Tetsudo Kk
• Toshiba Infrastructure Systems & Solutions Corp

Inventors

• Sato Kenji
• Ueno Masayuki
• Fukushima Takafumi
• Okada Shigekazu
• Oda Kotaro
• Otani Hiroaki
• Maki Yasuomi
• Kikkawa Kenichi
• Fujita Tsunehito
• Mori Manato

Classifications

• B60L9/24

  fed from AC supply lines · CPC title

• B60L58/10

  for monitoring or controlling batteries · CPC title

• B60L2200/26

  Rail vehicles · CPC title

• B60L1/003

  to auxiliary motors, e.g. for pumps, compressors · CPC title

• B60L50/51 Primary

  characterised by AC-motors · CPC title