A pulse width modulation device for converting direct voltage into a three-phase alternating voltage
CA 2218937 C · Owner: Asea Brown Boveri Ab · Inventors: Palsson, Rolf; Lindberg, Anders
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A device for converting direct voltage into a three phase alternating voltage having a two level converter connected to a direct voltage network and to an alternating voltage network. A control apparatus for performing pulse width modulation determines the pulse width modulation pattern for each phase by comparing a triangular wave for each phase with a reference alternating voltage. The triangular wave is inverted an even number of times during a fundamental oscillation of the reference alternating voltage and the time position of the inversions of each triangular wave is always such that two triangular waves are half a period displaced with respect to the third.
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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 November 12, 1997 and granted January 23, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 12, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 12, 2019.
- 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
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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.