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:
Mar. 11, 2008
Filed:
Aug. 17, 2006
Kiyoshi Sakamoto, Hitachi, JP;
Tsunehiro Endo, Hitachiota, JP;
Hidefumi Shirahama, Hitachi, JP;
Yoshiaki Ajima, Hitachiota, JP;
Kiyoshi Sakamoto, Hitachi, JP;
Tsunehiro Endo, Hitachiota, JP;
Hidefumi Shirahama, Hitachi, JP;
Yoshiaki Ajima, Hitachiota, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A driving apparatus of a synchronous motor fixes all the switching devices of an inverter at OFF in accordance with a value of an all-OFF control pulse signal outputted by a pulse generator. A motor current keeps flowing through free wheel diodes for a predetermined period even after all the switching devices shift to the OFF state. Therefore, pulse generator changes an induced voltage detection signal to an H (high) level after the passage of the time in which a motor current drops down to zero. A terminal voltage of the motor is taken in to acquire an induced voltage and a rotor position is estimated.