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:
Sep. 21, 1999
Filed:
Jun. 24, 1997
Yoshiaki Taga, deceased, late of Nerima-ku, JP;
Shigeo Taga, heir, Tokorozawa, JP;
Takiko Taga, heir, Tokorozawa, JP;
Tomoyo Taga, heir, Nagoya, JP;
Yasutomo Kawabata, heir, Aichi-gun, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
The prior art technique should return the voltage applied to a synchronous motor to zero in the process of measurement of an electrical angle. This causes foreign noises. The structure of the present invention utilizes the fact that the electrical angle of a three-phase synchronous motor 40 depends upon the inter-coil inductances. The procedure of the present invention applies a predetermined voltage for measurement to each combination of coils, and measures variations in electric currents flowing through the respective coils. The electric current flowing through each coil is attenuated in the presence of a driving current in the three-phase synchronous motor 40, compared with the case in the absence of a driving current. The procedure of the present invention accordingly refers to a table 122A to correct the observed values of electric currents based on the variations in electric currents, and refers to another table 122B to read the electrical angle .pi. corresponding to the corrected values of electric currents. The structure of the present invention can determine the electrical angle without returning the driving current to zero, thereby shortening the time period required for determination of the electrical angle while preventing the occurrence of foreign noises.