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:
Dec. 22, 1998
Filed:
Jan. 27, 1997
Thomson-CSF, Paris, FR;
Semikron International, Nuremberg, DE;
Abstract
Disclosed is a dc/ac inverter for the supply of alternating current to the windings of a synchronous electrical motor, especially for the traction of an electrical vehicle. During each half-wave of the alternating current, the dc/ac inverter with solid-state switches delivers steady levels of constant intensity. During each steady level, the intensity of the current is determined by the cyclical ratio of a chopping signal that controls the conduction of the transistor-based or thyristor-based switches. At zero speed of the rotor, the frequency f of the chopping signal has a value (f', 1 khz) smaller than the chopping frequency (8 kHz) for a speed different from zero. Thus the starting losses or the losses with the rotor off are minimized.