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Title:
METHOD FOR CONTROLLING VOLTAGE PWM CONVERTER
Document Type and Number:
Japanese Patent JPH1023760
Kind Code:
A
Abstract:

To reduce potential fluctuation, by adjusting a common-mode potential which is decided as the average of the sum of output voltages of different phases to zero by means of a three-level inverter constituted by connecting self-arc-extinguishing elements in series, by utilizing the fact that the output voltage of each phase changes to three levels.

An induction motor 6 is driven by rectifying electric power from an AC power sourcethrough a rectifier 2 and filtering the rectified electric power by means of capacitors 3 and 4, and then, constituting a multistage DC voltage PWM converter (three-level converter) 5. A control circuit 7 of the converter 5 is constituted of a voltage command selection section 701, a gate pulse generating section 702, a gate pulse processing section 703, and a pulse distributing section 704 and generates gate pulse signals (gu1-gw4) to the converter 5 based on three-phase command values Vu-Vw. The converter 5 generates output voltages Fu-Fw of U-W phases in accordance with the gate pulse signals to self-arc-extingushing elements 501-504 of the phases. The capacitors 3 and 4 prevent potential fluctuation by changing the output of the rectifier 2 at three levels by dividing the output into voltages of Vdc/2 each.


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Inventors:
KUBO KENJI
OKUYAMA TOSHIAKI
SUGAI HIROSHI
ISHIDA SEIJI
IBORI SATOSHI
Application Number:
JP17456296A
Publication Date:
January 23, 1998
Filing Date:
July 04, 1996
Export Citation:
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Assignee:
HITACHI LTD
International Classes:
H02M7/48; H02M7/483; H02M7/5387; H02P27/08; (IPC1-7): H02M7/48; H02M7/5387; H02P7/63
Attorney, Agent or Firm:
Ogawa Katsuo