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:
Nov. 25, 2014
Filed:
Mar. 15, 2012
Akira Bando, Hitachi, JP;
Masaya Ichinose, Hitachiota, JP;
Yasuhiro Kiyofuji, Hitachi, JP;
Yasuaki Nakayama, Hitachinaka, JP;
Akira Bando, Hitachi, JP;
Masaya Ichinose, Hitachiota, JP;
Yasuhiro Kiyofuji, Hitachi, JP;
Yasuaki Nakayama, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The excitation overcurrent detection unit for the doubly-fed electric machine is provided with a function to determine an excitation current magnitude relationship among three phases. The firing pulse is held to on-state or off-state to cause the largest-current phase and the second-largest-current phase to charge the DC capacitor by the operation of diodes. The conduction ratio of the third-largest-current phase or minimum current phase is controlled according to the detected current value to protect against a possible short-circuit across the DC capacitor. When the voltage of the DC capacitor exceeds a preset value, the voltage is suppressed by operating active or passive power devices.