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:
Apr. 26, 2016
Filed:
Apr. 12, 2012
Yoshitaka Iwaji, Tokyo, JP;
Ryoichi Takahata, Tokyo, JP;
Takahiro Suzuki, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An electric motor drive deviceincludes: an inverterthat drives a motor, a voltage division circuitthat serves as a neutral point potential detection unit that detects a neutral point potential of a stator winding of the motor; and a controllerthat estimates a rotor position of the motorbased on the detected neutral point potential, and that controls the inverterbased on an estimation result. A ground potential of the controlleris set to a negative side potential or a positive side potential of a DC voltage that is supplied to the inverter. The voltage division circuitdetects the neutral point potential with reference to the negative side potential or the positive side potential. The controllerestimates the rotor position based on a difference between a first neutral point potential detected during the ON/OFF operation of the inverterand a first fixed reference potential (⅔)Emax, and based on a difference between a second neutral point potential detected during the ON/OFF operation and a second fixed reference potential (⅓)Emax.