Abstract: A current sensing method measures a fractional current through a coil having a plurality of coil windings by using a current sensing resistor to measure a current through a subset of the plurality of coil windings and using a voltage sensor to measure a voltage drop across the current sensing resistor. The measured current and voltage values are provided to a processor to determine the fractional current and phase of the coil. For example, the fractional current and phase of the coil may be determined by calculating a total current of the coil as I=n(V/Rx), where n is the number of coil windings of the coil, V is the measured voltage, and Rx is the impedance of the current sensing resistor. The coil may be a secondary winding used in a wireless power transfer system.

Abstract: A charging frequency between a transmitting coil and a receiving coil of a wireless power transfer (WPT) system is found by setting an input voltage to the transmitting coil at a fixed voltage, shunting the receiving coil, determining a first input current frequency range in which a resonant frequency is expected to be found, frequency polling within the first input current frequency range using a set of polling frequencies in the first input current frequency range, and selecting as the charging frequency a polling frequency having a lowest input current. The first input current frequency range may be found by setting the first input current frequency range based on regulation, international electromagnetic frequency allotments, or prior experience with WPT between the transmitting coil and the receiving coil. A frequency range around the input current minima is selected to poll for a charging frequency that approximates the resonant frequency.

Abstract: A thin resonant induction wireless power transmission transfer coil assembly designed for low loss and ease of manufacturing includes one or more printed circuit boards having a first conductor pattern wound in a spiral on a first side and a second conductor pattern wound in a spiral on a second side thereof, where the second conductor pattern is aligned with the first conductor pattern whereby the second conductor pattern reinforces magnetic flux generated by the first conductor pattern. The first and second conductor patterns are placed relative to one another so as to provide flux transmission in a same direction. One or more of such printed circuit boards form a wireless power transmission coil assembly with a conductive winding layer, a ferrite flux diversion layer, conformal spacing layers, an eddy current shield layer and an assembly enclosure.

Abstract: Modular coil assemblies for wireless charging of vehicles have coil geometries and communications designed to limit electromagnetic field (EMF) levels in regions where humans or other living objects may be present. The modular coil assemblies are designed with the ability to shape the magnetic field to be predominately within shielding provided by the auto chassis by, for example, providing side-by-side phase cancellation or diagonal versus front-to-back (for 1×3, 2×3 array configurations) phase cancellation. The power levels and frequency offset pairwise compensation of the respective coils may be controlled to improve cancellation and thus to reduce magnetic field exposure potential. The phase cancellation of the magnetic flux density from respective coil assemblies varies over a range to provide, for example, ?50% cancellation at 125° offset and up to ?100% cancellation at 180°.

Abstract: A system and method for managing temperature internal to a Wireless Power Transfer (WPT) system for electric vehicles is provided. The thermal management system of the WPT system uses one or more of passive, semi-active, and active cooling approaches to manage the internal temperatures of the WPT system during a charging session. Improvements in thermal management allow for longer duration charging sessions and higher power charging sessions without the need to suspend charging for cool-down. Further, several different approaches to disguising and implementing the thermal management system in public spaces is also provided.

Abstract: Methods, systems, and computer-readable storage medium for improving the efficiency of charging an electric vehicle (EV) that follows a prescribed route. The efficiency of charging an electric vehicle is improved by receiving telemetry data from the EV, receiving charger data from a plurality of charges along the prescribed route, determining a charging plan for the EV based on a total cost per distance (TCD) of travel over each of the plurality of route segments that comprise the prescribed route and controlling a particular charger along the prescribed route to charge the EV according to the charging plan.

Abstract: Methods, systems, and computer-readable storage medium for improving the efficiency of charging an electric vehicle (EV) that follows a prescribed route. The efficiency of charging an electric vehicle is improved by receiving telemetry data from the EV, receiving charger data from a plurality of charges along the prescribed route, determining a charging plan for the EV based on a total cost per distance (TCD) of travel over each of the plurality of route segments that comprise the prescribed route and controlling a particular charger along the prescribed route to charge the EV according to the charging plan.

Abstract: An air-cooled subsurface vault houses a wireless power transfer charger for charging electric vehicles. The vault includes a cavity that receives the wireless power transfer charger and includes an air space around the wireless power transfer charger. At least two grates are positioned on respective sides of the wireless power transfer charger to enable bi-directional air-flow between the surface and the air space around the wireless power transfer charger. A temperature control element is further provided to regulate a temperature within the cavity and the at least two grates. The temperature control element may further include a heat exchanger positioned within the air space of the vault. Each grate is further adapted to act as an inlet or an outlet for the heat exchanger. A controller may be used to control operation of the heat exchanger to control venting duration and a direction of air flow in the cavity.

Abstract: A current sensing method measures a fractional current through a coil having a plurality of coil windings by using a current sensing resistor to measure a current through a subset of the plurality of coil windings and using a voltage sensor to measure a voltage drop across the current sensing resistor. The measured current and voltage values are provided to a processor to determine the fractional current and phase of the coil. For example, the fractional current and phase of the coil may be determined by calculating a total current of the coil as I=n(V/Rx), where n is the number of coil windings of the coil, V is the measured voltage, and Rx is the impedance of the current sensing resistor. The coil may be a secondary winding used in a wireless power transfer system.

Abstract: A resonant induction wireless power transfer coil assembly designed for low loss includes a wireless power transfer coil, a non-saturated backing core layer adjacent the wireless power transfer coil, an eddy current shield, a gap layer between the backing core layer and the eddy current shield, and an enclosure that encloses the wireless power transfer coil, backing core layer, gap layer and eddy current shield. The gap layer has a thickness in a thickness range for a given thickness of the backing core layer where eddy current loss in the eddy current shield is substantially flat over the thickness range. A thickness of the backing core layer and a thickness of the gap layer are selected where a total power loss comprising power loss in the backing core layer plus eddy current loss over the gap layer is substantially minimized.