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. 11, 2000
Filed:
May. 25, 1999
Kenji Oshima, Yokohama, JP;
Tetsuo Yamada, Gifu, JP;
Takashi Kodama, Nishikasugai-gun, JP;
Yasuhiro Yoshida, Nagoya, JP;
Otis Elevator Company, Farmington, CT (US);
Abstract
A multiple-wound, three-phase, variable speed motor having N independent winding sets is driven by N inverters, each responding to 1/N of the torque and excitation current commands, and the torque current is limited as a function of N times the limiting current each inverter may tolerate, when all inverters are functioning. When M inverters fail, they are disconnected from the motor, the torque current is limited as function of N-M times the limiting current each inverter may tolerate. The remaining N-M inverters may each respond to 1/(N-M) of the torque and excitation commands. The excitation current may be maximized as (N-M) times the limiting current divided by the square root of two. The speed command may be predetermined by the integration over an acceleration interval, of the maximum acceleration achievable with torque available from those of the inverters which have not failed, in view of the inverters' current limits.