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:
May. 08, 1990
Filed:
Jan. 19, 1989
Hiromi Inaba, Katsuta, JP;
Kiyoshi Nakamura, Katsuta, JP;
Akira Kimura, Katsuta, JP;
Sadao Hokari, Katsuta, JP;
Naoyuki Oouchi, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Engineering Co., Ltd., Hitachi, JP;
Abstract
Disclosed is an apparatus and method for controlling switching elements (51-56) of a PWM-controlled value type inverter by a software program using a microcomputer (10). The control apparatus of the present invention produces a switching element control signal (an on/off signal) according to the following steps. When a control command value commanding the output of the inverter is determined, a control mode corresponding to the commanded output value is selected from among a plurality of control modes (M1-M6) previously contained in a table to determine the switching elements to which the control signal is applied and the order of controlling the switching elements. Further, on the basis of the control command value, the difference between a modulation signal and a predetermined reference value is computed for each phase to determine the timing of controlling the switching elements. The unit control period of each control mode is divided into halves, and the switching element control timing is determined in each of the halves of the unit control period. The control signal is produced on the basis of the combination of the selected control mode and the determined control timing.