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:
Jan. 08, 2013
Filed:
Sep. 08, 2010
Hiroaki Ohya, Fukuoka, JP;
Masashiro Tanaka, Fukuoka, JP;
Yoichi Yamamoto, Fukuoka, JP;
Kabushiki Kaisha Yaskawa Denki, Kitakyushu-Shi, JP;
Abstract
An elevator control device includes a vector controller that calculates a voltage command required for driving an elevator cage, a carrier frequency switch circuit that outputs a carrier frequency signal, and a power converter that performs PWM control based on the voltage command and the carrier frequency signal, generates an AC power and supplies the AC power to an AC motor. The carrier frequency switch circuit changes the carrier frequency signal when a torque command for driving the AC motor reaches a torque limit value. Thus, it is possible to continuously operate an elevator without causing damage to a switching element of the power converter.