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. 02, 1993
Filed:
Apr. 23, 1992
Casilda D de Benito, Bloomfield, MI (US);
Roy I Davis, Canton, MI (US);
Richard J Hampo, Livonia, MI (US);
Prabhakar B Patil, Southfield, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A pulse width modulated (PWM) inverter is controlled by repetitively changing or dithering desired output currents for the inverter to ensure that it is unable to settle into zero states which result in lack of torque control when the inverter is used to control an AC motor. Dithering is performed by algebraically combining dither values with the desired output currents to generate reference output currents outside a hysteresis band used to control the inverter. Since the reference output currents are outside the hysteresis band, zero states are avoided. Dithering is performed by repetitively adding and subtracting first and second dither values form the desired output currents; or, repetitively adding a first dither value, adding a zero dither value and subtracting a second dither value form the desired output currents. The dither value can be approximately equal to half the hysteresis band, or approximately equal to or greater than half the hysteresis band.