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. 12, 2001
Filed:
Jun. 18, 1999
Junichi Takagi, Tochigi, JP;
Makoto Ishii, Utsunomiya, JP;
Noriaki Arakawa, Tochigi, JP;
Takeshi Wakatabe, Sano, JP;
Hideki Yoshida, Tochigi, JP;
Hideyuki Nakamura, Utsunomiya, JP;
Hideo Kumakura, Ashikaga, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
When inverter control is implemented in a refrigerator or the like, the rotating speed of a compressor motor is often operated at the preset minimum rotating speed. At this time, there has been a problem that when the DC voltage is boosted, the efficiency of the circuit drops due to switching loss in the power element. Still more, when the DC voltage is boosted even at the minimum rotating speed, the lowest voltage of the DC voltage must be controlled at 163 V or more including the fluctuation of the voltage. Therefore, there has been a problem in that the efficiency of the compressor motor also drops. To avoid these problems, when the temperature within a compartment of a refrigerator is cooled and approaches a preset temperature, and when a conduction ratio of the compressor motor falls below a preset value or a command on a rotating speed of the compressor motor becomes a preset rotating speed and the actual rotating speed also becomes the preset rotating speed, the control of the converter control circuit is turned off.