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:
Mar. 27, 2001
Filed:
Dec. 13, 1999
Tsuneo Kume, Arlington Heights, IL (US);
Mahesh M. Swamy, Gurnee, IL (US);
Yaskawa Electric America, Inc., Waukegan, IL (US);
Abstract
A noise attenuation circuit is disclosed for use in a motor drive system. The motor drive system includes a pulse width modulated inverter providing three phase power output on three phase conductors for driving a motor. The noise attenuation circuit includes a common mode transformer including a common mode choke having a core, with first, second and third choke windings on the core, each connected in series with one of the three phase conductors, and a fourth winding on the core. A three phase iron core transformer creates a neutral point representing common mode voltage. The iron core transformer has three primary windings connected in a wye configuration. A capacitor circuit is connected between the iron core transformer and the three phase conductors to prevent saturation of the iron core transformer during pulsed DC operating conditions. The fourth winding is connected between the neutral point and the DC bus and develops a common mode voltage that is equal and opposite to that existing in the system. This common mode voltage, when impressed across the three choke windings, effectively cancels the systems' common mode voltage thereby reducing the common mode current significantly.