Witricity Corporation

Bryan Ashworth Esteban

Milisav Danilovic

Kylee Devro Sealy

Kinjeo Yeung

Conor Joseph Rochford

Disclosed herein are systems and methods for low power excitation of wireless power transmitters configured to transmit high power. The exemplary systems and methods include disabling a power factor correction circuit of the transmitter, and adjusting one or more variable impedance components of the impedance network to obtain a minimum attainable impedance. The variable impedance components can be configured to operate between the minimum attainable impedance and a maximum attainable impedance. The systems and methods can include adjusting a phase shift angle associated with one or more transistors of the inverter and driving the transmitter such that the transmitter resonator coil generates a magnetic flux density less than or equal to a field safety threshold.

Systems and methods for low power excitation in high power wireless power systems

The disclosure features systems and methods for protecting transistors of a wireless power receiver. Systems can include a gate driver configured provide a control signal to control switching of the transistor gate such that power is transmitted to a load coupled to the receiver; and a controller coupled to the gate driver and configured to generate a protection signal. The protection signal can include (i) a fault signal indicating a fault in one or more components of the receiver; (ii) a signal indicating that the transistor gate should be latched; and/or (ii) at least one undervoltage signal indicating that an undervoltage condition exists in a power supply of the gate driver. Based on the generated protection signal, the gate driver can be configured to adjust the provided control signal to latch the transistor gate such that power is not transmitted to the load.

Gate driver implementations for safe wireless power system operation

One general aspect includes methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for fault protection of a bidirectional wireless power transfer system. The method includes the actions of detecting, by control circuitry of a wireless power transfer device, a fault for the bidirectional wireless power transfer system. Identifying an operating personality of the wireless power transfer device and a hardware configuration of the wireless power transfer device. Identifying, in response to detecting the fault and based on the operating personality and the hardware configuration, protection operations for protecting the wireless power transfer device from the fault. Controlling operations of the wireless power transfer device according to the protection operations. Other implementations of this aspect include corresponding systems, circuitry, controllers, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

Protection and control of wireless power systems

Disclosed herein are tunable reactance circuits configured to present a tunable or variable capacitive reactance when energized. The circuits can include a switch configured to be controlled by a gate driver, the gate driver configured to receive a control signal indicating an on-time of the switch; a diode coupled antiparallel to a switch; and one or more capacitors coupled in parallel to the diode. The tunable capacitive reactance can be based on the on-time of the switch and a total capacitance value of the one or more capacitors. The exemplary tunable reactance circuits may be used in wireless power transmitters and/or receivers for efficient power transmission and/or to deliver a particular level of power to a load.

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Belmont, MA, United States of America

Bryan Ashworth Esteban