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:
Oct. 02, 2007
Filed:
Aug. 18, 2005
Daigo Kaneko, Hitachi, JP;
Yoshitaka Iwaji, Hitachi, JP;
Kiyoshi Sakamoto, Hitachi, JP;
Tsunehiro Endo, Hitachi, JP;
Tomofumi Okubo, Narashino, JP;
Daigo Kaneko, Hitachi, JP;
Yoshitaka Iwaji, Hitachi, JP;
Kiyoshi Sakamoto, Hitachi, JP;
Tsunehiro Endo, Hitachi, JP;
Tomofumi Okubo, Narashino, JP;
Hitachi Industrial Equipment Systems Co., Ltd., Tokyo, JP;
Abstract
A synchronous motor driving apparatus having a power converter which applies AC variable voltages having variable frequency to a synchronous motor includes a pulsating current application unit for applying pulsating current to the synchronous motor and a magnetic pole position presumption unit. The magnetic pole position presumption unit detects two current values ΔIdcpand ΔIdcpon the positive side and two current values ΔIdcnand ΔIdcnon the negative side of the pulsating current and presumes the magnetic pole position of the synchronous motor on the basis of difference between change rates of ΔIdcp→ΔIdcpand ΔIdcp→ΔIdcp