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:
Jan. 05, 1993
Filed:
May. 16, 1991
Satoshi Ibori, Funabashi, JP;
Noritoshi Tuzi, Narashino, JP;
Yasumasa Toudou, Funabashi, JP;
Hiroshi Fujii, Chiba, JP;
Takatsugu Kambara, Funabashi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An inverter apparatus using a microcomputer control system suitable for use in driving an ac rotary electric machine is concerned. The inverter apparatus includes a device for detecting an output current or an output voltage of the inverter apparatus or a control signal supplied to the inverter apparatus and, from the detected result, detecting an output frequency of the inverter apparatus and a switch structure having memory function by means of change-over and selection of lines for holding data for setting therein an upper limit of the output frequency of the inverter apparatus in hardware manner. Thus, the device for detecting the output frequency of the inverter apparatus produces the output frequency of the inverter apparatus and the switch structure produces the exact upper limit of the output frequency which is not influenced by noise or the like. The comparison therebetween can suppress the output frequency of the inverter apparatus to the upper limit always reliably without permanent change due to noise or the like and a fear of changing data so that occurrence of over-rotational speed operation of the driven ac rotary electric machine can be prevented sufficiently.