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:
Nov. 16, 1993
Filed:
Nov. 21, 1991
Hidefumi Shirahama, Hitachi, JP;
Ikuo Yamato, Hitachi, JP;
Yoshimi Sakurai, Hitachi, JP;
Norikazu Tokunaga, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A structure is disclosed in which instantaneous phase and voltage difference values between the output voltage waveform from an inverter and the output voltage waveform from another AC power source are detected to correct the phase and the level of the output voltage waveform from the inverter so that the phase difference and the voltage difference can be controlled at high speed. As a result, excess current, which occurs if the inverter is operated at high frequencies, can be effectively controlled so that a stable parallel operation of the inverter with another AC power source is possible to perform.