A microprocessor based A.C. motor control circuit which can be used for both open and closed loop control includes a pair of RAMs for storing separate groups of synchronized digital waveforms for driving an A.C. motor. The microprocessor is used to calculate the group of digital waveforms required to maintain a controlled motor parameter at a desired value. One RAM has an output connected to supply the group of digital waveforms stored therein to a motor driver, while the second RAM is connected to receive a new group of digital waveforms which have just been calculated by the microprocessor. Once the new group of waveforms have been loaded into the second RAM, the microprocessor generates control signals to disconnect the output of the first RAM from the motor driver, and to connect the output of the second RAM to supply the newly calculated digital waveforms to the motor driver. The first RAM is then connected to receive the next group of digital waveforms to be calculated by the microprocessor.

Document Type


Primary Class


Secondary Class

363/41; 363/98; 363/132

Application Number


Filing Date

September 1980

Patent Number



The University of Toledo

Publication Date


Patent Country





The University of Toledo


University of Toledo Libraries

Digital Publisher

Digital Initiatives


These materials are free of copyright restrictions and are in the public domain within the United States only. The USPTO reserves the right to assert copyright protection internationally.



Rights Statement

Rights Statement

No Copyright - United States. URI: http://rightsstatements.org/vocab/NoC-US/1.0/
The organization that has made the Item available believes that the Item is in the Public Domain under the laws of the United States, but a determination was not made as to its copyright status under the copyright laws of other countries. The Item may not be in the Public Domain under the laws of other countries. Please refer to the organization that has made the Item available for more information.