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. 07, 2013
Filed:
Jun. 30, 2010
Satoshi Sumita, Hitachi, JP;
Kazuaki Tobari, Hitachiota, JP;
Shigehisa Aoyagi, Hitachi, JP;
Daisuke Maeda, Hitachinaka, JP;
Satoshi Sumita, Hitachi, JP;
Kazuaki Tobari, Hitachiota, JP;
Shigehisa Aoyagi, Hitachi, JP;
Daisuke Maeda, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
If magnitude relations between the output terminal voltage based on a DC negative terminal of the inverter and a threshold voltage that is a fixed value are compared, polarity thereof is changed at a predetermined rotor phase. The magnitude relation, for example, is detected by an inexpensive and simple apparatus such as a level shift circuit and a NOT circuit. The rotor phase of the permanent magnet synchronous motor is inferred on the basis of changes in the magnitude relation and if it is differentiated, a rotation speed is inferred. If the inferred values of the rotor phase and rotation speed are fed back to synchronous operation or vector control, the free-running permanent magnet synchronous motor is restarted.