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:
Dec. 29, 1998
Filed:
Feb. 27, 1997
Yoshiaki Taga, deceased, late of Tokorozawa, JP;
Shigeo Taga, heir, Tokorozawa, JP;
Takiko Taga, heiress, Tokorozawa, JP;
Tomoyo Taga, heiress, Nagoya, JP;
Yasutomo Kawabata, Aichi-gun, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
An electrical angle detecting device for detecting the electrical angle of a synchronous motor utilizes differences in inductance between phases with the angle of a rotor 50 to determine electrical angle. Voltage is applied across predetermined phases, the currents Iu, Iv, Iw flowing through U, V, W phases as a function of the differing inductance with angle of the rotor 50 are simultaneously detected, and the electrical angle is determined from relationships among the three currents stored in memory beforehand. In a first stage, the electrical angle is determined in the 0-.pi. range or the .pi.-2.pi. range by an approximation calculation and in a second stage the asymmetry of the maximum currents produced by the voltage applied across the phases is utilized to ascertain the range in which the electrical angle falls. the electrical angle can thus be unambiguously ascertained to enable sensorless detection of rotor position (electrical angle) even when the rotor is at rest or is rotating slowly.