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:
Jul. 10, 1984
Filed:
May. 24, 1982
Hiroshi Nagase, Hitachi, JP;
Toshiaki Okuyama, Ibaraki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A control apparatus for induction motor comprising an induction motor driven by a power converter, a circuit for producing an effective current command value for the induction motor on the basis of a speed command value and an actual speed value, a circuit for producing a slip frequency corresponding to the magnitude of the effective current command value, and a circuit for producing a primary frequency command value on the basis of the slip frequency and the actual speed value, the output of the power converter being controlled on the basis of the frequency command value, the effective current command value and a given exciting current or voltage command value, wherein the control apparatus further comprises a current component detecting circuit for detecting the primary current of the induction motor so as to produce in the form of a DC signal an actual effective current value which is an effective component of the detected primary current, a first current control circuit for producing an effective voltage command value in the form of a DC signal on the basis of the actual effective current value and the effective current command value, and a converter controlling circuit for controlling the power converter to produce output on the basis of the effective voltage command value, the frequency command value, and a given exciting voltage command value in the form of a DC signal. The current component detecting circuit preferably further produces in the form of a DC signal an actual exciting current value which is an exciting component of the detected primary current, and the controlling apparatus may further comprise a second current controlling circuit for producing the exciting voltage command value on the basis of the actual exciting current value and the predetermined exciting current command value.