Single-coil wireless power transfer has an alignment problem: move the receiver and efficiency collapses. US11404910B2, granted to Raytheon Company on August 2, 2022, claims a way around it — a multi-cell array of transmitter coils. Claim 1’s novelty is the array and how it is regulated, not the physics of any one link.

The CPC tags span power transfer and vehicle charging: H02J 50/12 (inductive transfer), H01F 38/14 (transformer-type coil coupling), B60L 53/12 and 53/36 (contactless vehicle charging), plus H02M 7/5387 for the inverter driving the coils. The combination describes a system where multiple cells can be energized depending on where the receiver sits.

“A multi-cell inductive wireless power transfer system includes multiple transmitting elements. Each transmitting element includes one or more transmitting windings and one or more transmitting magnetic cores.”— U.S. Patent No. 11,404,910 source

The granted claim 1 is more demanding than that abstract sentence. It recites a full power-converter system: each cell has multiple transmitting elements (each a winding plus a magnetic core) and multiple receiving elements; a transmitting power-converting circuit turns an input signal into a drive signal for the transmit elements; a receiving power-converting circuit turns the transferred signal back into an output to drive a load; and — the load-bearing limitation — a controller “in signal communication” with both circuits that “actively adjust[s] one or both of transmitting phase angles…and receiving phase angles…so that the transmitting phase angles match the receiving phase angles.” The invention is not the array of coils per se. It is the active phase-matching control across that array.

That distinction matters for what the patent actually fences. Phase alignment between transmit and receive sides governs how efficiently real power crosses the air gap; if the phases drift, power circulates as reactive current and the link bleeds efficiency. By making the controller continuously drive transmit and receive phase angles into agreement — and, per dependent claim 12, by matching the switching frequencies of the transmit-side and receive-side switches so the phase angles track — the system holds efficiency as conditions change. That is a more defensible fence than “an array of coils,” which on its own would face heavy prior art.

The dependent claims build out a recognizable power-electronics topology. Claim 3 makes the transmit circuit a DC-AC converter fed from a “prime power source”; claim 5 makes the receive circuit an AC-DC converter; claims 4 and 6 cast both as the two bridges of a bidirectional dual active bridge (DAB) — a standard architecture for controlled bidirectional power flow. Claim 9 connects the transmit elements in series and the receive elements in parallel; claims 10–11 separate windings onto distinct insulating layers. The picture is a DAB-driven, phase-controlled coil array in which the controller is the thing being claimed, with the magnetics and bridges as the supporting cast.

Reading scope strictly, the limitation is the active phase-angle (and frequency) matching across a multi-cell array, which is narrower than “wireless power transfer” and broader than any specific cell geometry. It is a defensible middle: novel enough to clear single-coil and fixed-drive array art, general enough to cover various array implementations — as long as they hold transmit and receive phases together under active control.

The caution: a phase-matching coordination claim does not own array-based wireless power. A competitor that regulates coupling by switching cells on and off, by tuning resonant capacitors, or by mechanically aligning coils — rather than by actively matching transmit and receive phase angles — can plausibly route around claim 1. And given the assignee, this reads as much like a defense and mobility IP play as a grid one; the B60L vehicle-charging tags hint at dynamic or static EV charging, but the bidirectional DAB framing leaves room for grid-adjacent power exchange. For our beat, it is a clean data point on how the wireless-power field moved from single links to actively coordinated arrays in the early 2020s — and on the fact that the patentable substance migrated into the control law, not the coils.

The dual-active-bridge framing deserves a second look, because it is what makes the phase-matching limitation more than a slogan. In a DAB, power flow and direction are governed by the phase shift between the two bridges — that is the standard control variable for the topology. By recasting the wireless link as a DAB whose primary and secondary bridges are separated by the air gap rather than a transformer winding, the inventors get to claim phase control as the mechanism for steering power across that gap. Dependent claim 8’s capacitor between the receive-side switches and the receive element, and claim 7’s filter on the transmit side, are the resonant-tuning elements that let the magnetics behave like the transformer a DAB expects. The series-transmit, parallel-receive arrangement of claim 9 is a deliberate impedance choice: series transmit elements share a common current so their phases can be driven together, while parallel receive elements present a stiff output to the load. None of these is exotic on its own, but stacked together they describe a system in which the only way to hold efficiency as the receiver moves is to keep re-matching phase — which is exactly the limitation claim 1 reserves. That is the signature of a well-constructed claim: the supporting hardware is arranged so that the claimed control step is not optional but structurally required, which makes the fence harder to step around without rebuilding the system on a different principle.