Witricity Corporation

Mircea-Florian Vancu

Hans Peter Widmer

Marcel Fischer

Prasanth Venugopal

Lukas Frank Sieber

Andreas Daetwyler

Systems and methods are described for active harmonics cancellation. A wireless charging apparatus includes a wireless-power transfer circuit comprising a wireless-power transfer coil configured to generate or couple to a magnetic field to transfer or receive power and a plurality of tuning capacitors electrically coupled to the wireless-power transfer coil. The apparatus also includes a power converter circuit electrically coupled to the wireless-power transfer circuit. Additionally, the apparatus includes a signal generation circuit different from the power converter circuit and electrically coupled to one or more nodes between capacitors of the plurality of tuning capacitors. The signal generation circuit is configured to generate and inject a signal into the wireless-power transfer circuit at the nodes between the capacitors. The signal generation circuit includes a rejection filter tuned to an operating frequency of the wireless-power transfer coil.

Active harmonics cancellation

The present disclosure describes techniques for detecting foreign objects by detecting changes in an electrical characteristic of an array of sense elements for detection objects based on a current measurement approach. In some aspects, an apparatus for measuring changes in current for detecting objects is provided. The apparatus includes a plurality of sense circuits each comprising a sense coil, the plurality of sense circuits each electrically connected to a common output node. The apparatus further includes a driver circuit electrically connected to the plurality of sense circuits and configured to operate as a voltage source and selectively apply a voltage signal at an operating frequency to each of the plurality of sense circuits. The apparatus further includes a current measurement circuit electrically connected to the common output node. The current measurement circuit is configured to provide a measurement output proportional to an electrical current at the common output node.

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Schlieren, Switzerland

Mircea-Florian Vancu