Slip control based on sensing voltage fed to an induction motor
CA 2044075 C · Owner: Rowan, Timothy M. · Inventors: Kerkman, Russel J.; Rowan, Timothy M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An electronic motor drive for vector control of an induction motor controls slip and operating frequency in response to changes in stator voltage. The drive includes a torque control loop, a flux control loop and a frequency control loop which includes slip control in response to a voltage difference. In the constant horsepower range above, base speed, slip is controlled in response to an error between a d-axis reference voltage that is sampled at base speed and a d-axis feedback voltage that is sensed when the motor is operating above base speed. Flux-weakening is provided in response to an error between a q-axis reference voltage that is sensed when the motor is operating at base speed …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed June 7, 1991 and granted February 13, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 7, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 7, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.