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. 16, 1980
Filed:
Jun. 30, 1978
Applicant:
Inventors:
Toshiaki Okuyama, Hitachi, JP;
Yuzuru Kubota, Hitachi, JP;
Hiroshi Nagase, Hitachi, JP;
Katsunori Suzuki, Takahagi, JP;
Assignee:
Hitachi, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318721 ; 318722 ; 318800 ;
Abstract
A synchronous motor having multi-phase armature windings and a field winding is drived by a frequency converter. Actual torque is determined from a sinusoidal position signal representative of rotational position of the synchronous motor and the armature current. The actual torque value is compared with a command torque signal, whereby the armature current is controlled in dependence on difference or deviation resulting from the comparison thereby to cancel the torque ripple. Torque ripple can thus be suppressed to a satisfactory degree even at a low rotation speed of the synchronous motor.