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US7176645: Control apparatus for electric railcar

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Filing Information

Inventor(s) Motomi Shimada · Akira Horie ·
Assignee(s) Hitachi, Ltd. ·
Attorney/Agent(s) Antonelli, Terry, Stout and Kraus, LLP. ·
Primary Examiner Lincoln Donovan ·
Assistant Examiner Tyrone Smith ·
Application Number US11107737
Filing date 04/18/2005
Issue date 02/13/2007
Prior Publication Data
Predicted expiration date 06/27/2023
Patent term adjustment 3
U.S. Classifications 318/432  · 318/376  · 318/371  · 318/374  · 318/436  · 701/19  · 701/20  · 318/434  ·
International Classifications H02P700  ·
Kind CodeB2
Related U.S. Application DataCROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. application Ser. No. 10/601,629, filed Jun. 24, 2003, now abandoned, the contents of which are incorporated herein be reference.
Foreign Priority JP2002188978 - 06/28/2002 ·
8 Claims, 6 Drawings


Abstract

A control apparatus for an electric railcar that provides control so that when rotational speed of a motor decreases below a required value, torque of the motor will decrease at a required rate of change, a current limiter for limiting a torque current command “(A)Iqp” output from a current command arithmetic unit is provided to ensure that when the rotational speed of the motor decreases below the required value, the torque current command will be limited to a command value “(B)Iqp” smaller than that command value, and to ensure that a carrier frequency at which PWM signals are created when switching elements of the electric power converter are controlled by carrier generator is controlled to become lower than a carrier frequency existing when the rotational speed of the motor decreases below the required value.

Independent Claims | See all claims (8)

  1. 1. A control apparatus for an electric railcar comprising: an electric power converter for driving a motor; means for detecting the rotational speed of said motor; means for controlling said electric power converter; means for decreasing the braking torque of said motor gradually from a first braking torque to a second predetermined braking torque which is larger than zero and smaller than said first braking torque when an AND condition which indicates the brake command is in existence and the rotational speed of said motor decreases below a first predetermined speed is satisfied; and means for maintaining the braking torque of said motor constantly to said second predetermined braking torque until the rotational speed of said motor becomes zero.
  2. 3. A control apparatus for an electric railcar comprising: an electric power converter for driving a motor; means for detecting a rotational speed of said motor; means for controlling said electric power converter; means for creating PWM signals with a first carrier frequency; means for controlling switching elements constituting said electric power converter using said PWM signals; and means for selecting a second carrier frequency which is lower than said first carrier frequency for creation of PWM signals when an AND condition which indicates the brake command is in existence and the rotational speed of said motor decreases below a predetermined low speed is satisfied.
  3. 5. A control apparatus for an electric railcar comprising: an electric power converter for driving a motor; means for detecting a rotational speed of said motor; means for controlling said electric power converter; means for decreasing the braking torque of said motor gradually from a first predetermined braking torque to a second braking torque which is larger than zero and smaller than said first braking torque when an AND condition which indicates the brake command is in existence and the rotational speed of said motor decreases below a first predetermined speed is satisfied; means for maintaining the braking torque of said motor constantly to said second predetermined braking torque until the rotational speed of said motor becomes zero; means for creating PWM signals with a first carrier frequency; means for controlling switching elements constituting said electric power converter using said PWM signals; and means for selecting a second carrier frequency which is lower than said first carrier frequency for creation of PWM signals when an AND condition which the brake command is in existence and the rotational speed of said motor decreases below a predetermined low speed is satisfied.

References Cited

U.S. Patent Documents

Document NumberAssigneesInventorsIssue/Pub Date
US3899725 GEN ELECTRIC Plunkett Aug 1975
US4000872* Westinghouse Air Brake Company Grundy Jan 1977
US4785225 Ltd. Hitachi Horie et al. Nov 1988
US5010283* Sankyo Seiki Mfg. Co., Ltd. Kitajima et al. Apr 1991
US5184049* Sankyo Seiki Mfg. Co., Ltd. Kiuchi Feb 1993
US5677610 Ltd. Hitachi Tanamachi et al. Oct 1997
US5757153 Honda Giken Kogyo Kabushiki Kaisha Ito et al. May 1998
US5896283 Denso Corporation Usami Apr 1999
US5992950* General Electric Company Kumar et al. Nov 1999
US6456909* Hitachi, Ltd. Shimada et al. Sep 2002
US6831432* Matsushita Electric Industrial Co., Ltd. Murakami Dec 2004
US20030043609* Ishida et al. Mar 2003
US20030052642* Kerkman et al. Mar 2003
US20040000888* Shimada et al. Jan 2004

Foreign Patent Documents

Document NumberAssigneesInventorsIssue/Pub Date
EP0031710WESTINGHOUSE ELECTRIC CORPORATIONJul 1981
EP1077527Holtz, Joachim, Prof. Dr. Ing.Feb 2001
JP3164003Jul 1991
JP7212911Aug 1995
JP2001251701HITACHI LTDSep 2001
JP2002034101HITACHI LTDJan 2002
JP2002171602HITACHI LTDJun 2002
* cited by examiner

Referenced By

Patent Family

Document NumberAssigneeInventorsIssue/Pub Date
US20050184693 Motomi Shimada et al. Aug 2005
US7176645 Hitachi, Ltd. Motomi Shimada et al. Feb 2007