The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 12, 2006
Filed:
Jul. 19, 2004
Kazuaki Tobari, Hitachiota, JP;
Tsunehiro Endo, Hitachiota, JP;
Hidefumi Shirahama, Hitachi, JP;
Yoshiki Itou, Naka, JP;
Kazuaki Tobari, Hitachiota, JP;
Tsunehiro Endo, Hitachiota, JP;
Hidefumi Shirahama, Hitachi, JP;
Yoshiki Itou, Naka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method and apparatus for controlling a permanent magnet synchronous motor by accurately detecting 3-phase motor currents from a DC input current in a full voltage range are provided. In the motor control apparatus for detecting the 3-phase motor currents on the basis of the value of the current detected at a DC side of a PWM inverter, when a difference width between PWM pulse signals of two of three phases of the 3-phase PWM inverter which cannot detect the motor currents is not larger than a predetermined value or when the output voltage of the 3-phase PWM inverter is low, the apparatus automatically reduce the carrier frequency of the PWM inverter.