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. 18, 1997
Filed:
Oct. 24, 1995
Mark Robert Vitunic, San Jose, CA (US);
Micro Linear Corporation, San Jose, CA (US);
Abstract
A circuit for powering a three-phase AC induction motor. The circuit generates a first signal of the form Vdc+A sin (2.pi.ft-0.degree.) and a second signal of the form Vdc+A sin (2.pi.ft-90.degree.) as is done in conventional circuits for powering two-phase AC induction motors. A vector summation circuit is used to create a third signal from the first two signals. The third signal is of the form Vdc+A sin (2.pi.ft+60.degree.). The first signal is input to a first error amplifier along with a first sampled difference signal from the motor. The third signal is input to a second error amplifier along with a second sampled difference signal from the motor. The outputs from each of the first and second amplifiers is input into a first comparator and a second comparator along with a sawtooth waveform to create a first sinusoidally modulated square wave signal and a second sinusoidally modulated square wave signal. The first and second sinusoidally modulated square wave signals are fed to driver circuits which in turn control an H-bridge circuit for powering the motor from a DC bus. Therefore, the invention achieves two-phase control of a three-phase AC induction motor.