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:
Jan. 08, 2013
Filed:
Apr. 01, 2010
Andreas Doktar, Vaasa, FI;
Stefan Strandberg, Vörå, FI;
Jaakko Ollila, Pirkkala, FI;
Vacon Oyj, Vaasa, FI;
Abstract
Method and apparatus to start a frequency converter equipped with a direct current intermediate circuit, particularly when a permanent magnet motor whose rotor is rotating at the start-up time is connected to it, wherein the frequency converter has a network bridge () and load bridge (), and the load bridge has controllable power semiconductor switches of the upper and lower branch (V-V) and parallel connected zero diodes (D-D), and a direct current intermediate circuit between them, and the said frequency converter uses a current transducer placed in the direct current intermediate circuit, and the analogue current signal composed by it features samples of the measured output currents, and the diverter switches of the frequency converter's upper branch are controlled using the bootstrap method, wherein start-up is initiated by controlling the controllable power semiconductor switch of the lower branch of at least one output phase to a conductive state for one or several periods of time, preferably of approximately 200 μs, at a time.