Abstract: A system for balancing and converting voltage output from photovoltaic modules includes a set of solar substrings and a power conversion circuit. The power conversion circuit includes a balancing section configured to balance voltage output from the set of solar substrings. The power conversion circuit also includes a voltage control section including: a first transformer coupled to the set of solar substrings and configured to step-up voltage from the set of solar substrings; a second transformer arranged in series to the first transformer; and an output capacitor coupled to the second transformer. The system further includes a controller configured to: drive a set of modulation signals to the balancing section and the voltage control section; alternate voltage polarities across the first transformer and the second transformer; and modify output voltage of the power conversion circuit to a target output voltage.

Abstract: One variation of a system for regulating power output of multiple solar substrings includes: a set of solar substrings and a power regulator. The power regulator includes: a power supply; an adder; a modulation signal generator; a de-modulator; and an integrator. The power supply is configured to receive an input voltage from the set of solar substrings. The adder is configured to modify a voltage gain of the input voltage at the power supply. The modulation signal generator is coupled to the adder and configured to generate an oscillating power signal at the power supply. The de-modulator is configured to de-modulate the oscillating power signal output from the power supply. The first integrator: is coupled to the de-modulator and the adder; and configured to define voltage gain step at the power supply based on a DC signal component output from the de-modulator.

Abstract: A system for balancing and converting voltage output from photovoltaic modules includes a set of solar substrings, a power conversion circuit, and a controller. The power conversion circuit includes: a set of windings coupled in series and arranged in parallel to the set of solar substrings; a set of switches coupled in parallel and interposed between the set of solar substrings and the set of windings; and an output switch coupled in series to a first switch, in the set of switches, and an output capacitor. The controller is configured to: oscillate states of the set of switches and the output switch at a first duty cycle; balance voltages output from the set of solar substrings across the set of windings to a nominal output voltage; and modify the nominal output voltage to a target voltage directed to the target load based on the first duty cycle.

Abstract: An apparatus is disclosed for wireless power transmission. The apparatus may include a resonator circuit configured to generate a magnetic field to couple to a power receiving unit. The resonator circuit may include a transmit coil and an electromechanical reactive device having one or more moveable components, and having a reactance that is determined by a physical arrangement of those components. A power circuit connected to the resonator circuit can provide power to drive the transmit coil to generate the magnetic field. The electromechanical reactive device of the resonator circuit can be actuated to change the physical arrangement of the one or more moveable components, and hence change the reactance.

Abstract: Certain aspects of the present disclosure are generally directed to apparatus and techniques for protecting electronic devices that may be prone to damage by wireless charging fields. For example, the apparatus may include a wireless charging circuit configured to selectively generate a wireless charging field and an impedance detection circuit coupled to the wireless charging circuit and configured to detect an impedance change corresponding to the wireless charging field. In this case, a proximity detection circuit may selectively detect proximity of one or more electronic devices that are prone to damage by the wireless charging circuit. In some aspects, detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, and wherein generating the wireless charging field comprises reducing a transmit power of the wireless charging field based on detecting the impedance change.

Abstract: Certain aspects of the present disclosure are generally directed to apparatus and techniques for protecting electronic devices that may be prone to damage by wireless charging fields. For example, the apparatus may include a wireless charging circuit configured to selectively generate a wireless charging field and an impedance detection circuit coupled to the wireless charging circuit and configured to detect an impedance change corresponding to the wireless charging field. In this case, a proximity detection circuit may selectively detect proximity of one or more electronic devices that are prone to damage by the wireless charging circuit. In some aspects, detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, and wherein generating the wireless charging field comprises reducing a transmit power of the wireless charging field based on detecting the impedance change.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus for controlling a power level of wireless power transfer. Certain aspects provide a wireless power receiver. The wireless power receiver includes an antenna and a rectifier. The rectifier includes a first diode and a second diode. The wireless power receiver further includes a resistor in parallel with the first diode. A first terminal of the resistor is coupled to a first terminal of the first diode. A second terminal of the resistor is coupled to a second terminal of the first diode.

Abstract: Certain aspects of the present disclosure relate to systems and methods for using electrostatic deflection of tissue to generate ultrasound power signals, such as for powering medical implants. Certain aspects of the present disclosure provide a system for generating ultrasonic pressure waves. The system includes an electrode configured to be positioned near a tissue. The system further includes an AC signal generator coupled to the electrode, wherein the AC signal generator is configured to apply an AC signal to the electrode causing the tissue to vibrate to generate ultrasonic pressure waves directed to an ultrasonic power receiver implanted under the tissue.

Abstract: A system for detecting and characterizing an object proximate to a wireless power transmitting unit includes a transmit circuit having a transmit antenna, the transmit circuit configured to transmit at least one signal having a frequency related to a fundamental power transmit frequency, the transmit circuit configured to measure a response of the transmit antenna, and a controller circuit configured to characterize the object based on the response of the transmit antenna.

Abstract: Certain aspects of the present disclosure are generally directed to apparatus and techniques for protecting electronic devices that may be prone to damage by wireless charging fields. For example, the apparatus may include a wireless charging circuit configured to selectively generate a wireless charging field and an impedance detection circuit coupled to the wireless charging circuit and configured to detect an impedance change corresponding to the wireless charging field. In this case, a proximity detection circuit may selectively detect proximity of one or more electronic devices that are prone to damage by the wireless charging circuit. In some aspects, detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, and wherein generating the wireless charging field comprises reducing a transmit power of the wireless charging field based on detecting the impedance change.

Abstract: Certain aspects of the present disclosure generally relate to modulated warning lights for vehicles. In some aspects, a device may include an emitter to emit a warning light. The warning light may be in a visible spectrum. The device may include a modulator to modulate the warning light to generate a modulated warning light. The modulated warning light may be modulated to a particular pattern selected to convey a message. The message may be used to identify a carrier to which the device is attached such that the carrier is identifiable by a computer vision system that receives the modulated warning light.

Abstract: Certain aspects of the present disclosure generally relate to modulated warning lights for vehicles. In some aspects, a device may include an emitter to emit a warning light. The warning light may be in a visible spectrum. The device may include a modulator to modulate the warning light to generate a modulated warning light. The modulated warning light may be modulated to a particular pattern selected to convey a message. The message may be used to identify a carrier to which the device is attached such that the carrier is identifiable by a computer vision system that receives the modulated warning light.

Abstract: Wireless power transfer for integrated cycle drive systems is described. A cycle power system includes a rim that is connected to, and positioned concentrically with, a sealed housing that can rotate about an axis. The cycle power system also includes an integrated drive system disposed within the housing. The integrated drive system includes a battery and a motor for driving a cycle by causing rotational movement of the rim about the axis. Additionally, the cycle power system includes an inductive structure that is disposed within the housing, and that wirelessly charges the battery through induction between the inductive structure and remote a charging station.

Abstract: An apparatus for wirelessly receiving power via a wireless field generated by a transmitter includes a resonator configured to generate electrical current to power or charge a load based on a voltage induced in the resonator in response to the wireless field, a first variable capacitor electrically coupled to the resonator and configured to adjust a first capacitance of the first variable capacitor responsive to a first control signal, a second variable capacitor electrically coupled to the resonator and configured to adjust a second capacitance of the second variable capacitor responsive to a second control signal, and a control circuit configured to adjust and apply the first control signal and the second control signal to the first variable capacitor and the second variable capacitor, respectively, to adjust a resonant frequency of the resonator and a voltage output to the load based on an electrical characteristic indicative of a level of power output to the load.

Abstract: A multi-level rectifier is presented that is suitable for use at high frequencies, including into MHz range such as in the 6.78 MHz band used for wireless power transfer. To maintain the proper timing or switching waveform when operating at high frequencies, a feedback loop is used. The rectification circuit includes a multi-level waveform generator circuit that generates a multi-level control waveform from the input waveform and an indication of its current. The multi-level control waveform is maintained in phase with the input waveform. A control signal generation circuit receives the multi-level control waveform and generates control signals corresponding to levels of the multi-level control waveform. A synchronous rectifier receives the input waveform and includes a plurality of switches to provide an output voltage generated from the input waveform. The switches are coupled to receive the control signals and the output voltage is a function of the multi-level control waveform.

Abstract: Disclosed is a current sensor that senses current flow in a conductor by coupling a first magnetic field generated by the conductor to a sense element. The current sensor includes a shield including a first material that sandwiches the sense element to define a stack and a second material that sandwiches the stack. The shield is configured to generate a second magnetic field, responsive to a third magnetic field external to the current sensor that opposes the third magnetic field. The shield is further configured to prevent production of a magnetic field that opposes the first magnetic field generated by the flow of current in the conductor.

Abstract: Exemplary implementations are directed to wireless power in-band signaling by load generation. An apparatus for communicating with a wireless power transmitter is provided. The apparatus comprises a receiver configured to generate a voltage based on wirelessly received charging power from the transmitter. The apparatus comprises a load configurable to be coupled to and decoupled from the receiver. The apparatus comprises a switching circuit configured to encode a communication to the transmitter by adjusting an average power dissipated by the load detectable by the transmitter. The average power is based on a duty cycle with which the switching circuit couples and decouples the load from the receiver under control of a control signal.

Abstract: Resonant rectifier topologies are described for tuning the rectifier so that it performs from an electromagnetic interference (EMI) point of view, while maintaining the voltage regulation at the output that a series tuned rectifier would maintain. Examples include a an inductor of a receive coupler and a rectifier connectable to drive a load, along with first and second filter elements that are each configured to provide an impedance inversion function in a frequency band and that are connected in series between the inductor of a receive coupler and rectifier. In one set of examples, both filter elements are implemented as pair filters, while in other examples the first filter element includes the inductor of a receive coupler in parallel with a capacitance connected to ground.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus for controlling a power level of wireless power transfer. Certain aspects provide a wireless power receiver. The wireless power receiver includes an antenna and a rectifier. The rectifier includes a first diode and a second diode. The wireless power receiver further includes a resistor in parallel with the first diode. A first terminal of the resistor is coupled to a first terminal of the first diode. A second terminal of the resistor is coupled to a second terminal of the first diode.

Abstract: Wireless power transfer for integrated cycle drive systems is described. A cycle power system includes a rim that is connected to, and positioned concentrically with, a sealed housing that can rotate about an axis. The cycle power system also includes an integrated drive system disposed within the housing. The integrated drive system includes a battery and a motor for driving a cycle by causing rotational movement of the rim about the axis. Additionally, the cycle power system includes an inductive structure that is disposed within the housing, and that wirelessly charges the battery through induction between the inductive structure and remote a charging station.