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:
Jun. 11, 1991
Filed:
Jul. 14, 1989
Nobuyoshi Mutoh, Katsuta, JP;
Keijiro Sakai, Hitachiota, JP;
Akiteru Ueda, Ibaraki, JP;
Hiroshi Fujii, Chiba, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A PWM inverter apparatus used for driving an a.c. motor, including an inverter having an output part connected to the a.c. motor and switching elements on-off controlled by a PWM signal. The inverter apparatus also includes a part for receiving, at an interval of a given sampling period, status command information specifying a desired status of a vector of a rotating magnetic flux in the a.c. motor; a part for predicting, on the basis of at least the status command information received at each sampling time, the status of the vector of the rotating magnetic flux which will be produced at a next sampling time; a part for calculating a difference vector between the status of the vector of the rotating magnetic flux specified by the status command information received at a present sampling time and the predicted status of the vector of the rotating magnetic flux which will be produced at a next sampling time; a part for synthesizing the difference vector using selected reference voltage vectors from among a plurality of predetermined reference voltage vectors; and a part for generating a PWM signal for controlling the switching elements of the inverter so as to produce the selected reference voltage vectors.