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. 31, 2006
Filed:
Mar. 18, 2003
Shuji Fujita, Nishikamo-gun, JP;
Atsuo Sakai, Okazaki, JP;
Shuji Fujita, Nishikamo-gun, JP;
Atsuo Sakai, Okazaki, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Toyoda Koki Kabushiki Kaisha, Kariya, JP;
Abstract
A motor-current square value calculation sectioncalculates, as a motor-current square value, the sum of respective square values of two phase currents converted from three phase currents flowing through an electric motor. A temperature estimation calculation sectionperforms low-pass filtering for the motor-current square value, and calculates temperature increases of the mass portion and coils on the basis of the filtered motor-current square value. In the low-pass filtering, filtering calculation is performed in a manner which changes depending on rotational speed RV of the electric motor; i.e., whether the electric motor is in a rotating state or in a stopped state. The temperature increase of the mass portion is added to ambient temperature of the electric motor to thereby estimate temperature of the mass portion, and the temperature increase of the coils is added to the estimated temperature of the mass portion to thereby estimate temperature of the coils. Accordingly, the coil temperature of the electric motor can be accurately detected, and current flowing through the electric motor is properly controlled in accordance with the detected temperature.