Disclosed herein are a wireless power transfer apparatus, a method for wireless power transfer and a method of detecting a resonant frequency used in a wireless power charging system or a wireless power transfer. The wireless power transfer apparatus includes a plurality of transmission coils, each of which transmits power to a receiver coil through magnetic resonance; a signal generator transmitting signals having different resonant frequencies to the plurality of transmission coils, the signal generator being connected to the plurality of transmission coils; and a feedback unit transferring information on amounts of powers which are respectively output by the plurality of transmission coils to the signal generator.

The implementation of modal processors, which involve the parallel combination resonant filters, may be costly for applications such as artificial reverberation that can require thousands of modes. In one embodiment, the input signal is decomposed into a plurality of subbands, the outputs of which are downsampled. In each downsampled band, resonant filters are applied at the downsampled sampling rate, and their output is upsampled and filtered to form the band output. In these and other embodiments, a feature of responses of the mode filters have been optimized to minimize an aspect of a residual error after a point in time.

Analysis of smart meter and/or similar data based on frequency content is disclosed. In various embodiments, for each of a plurality of resource consumption nodes a time series data including for each of a series of observation times a corresponding resource consumption data associated with that observation time is received. At least a portion of the time series data, for each of at least a subset of the plurality of resource consumption nodes, is transformed into a frequency domain. A feature set based at least in part on the resource consumption data as transformed into the frequency domain is used to detect that resource consumption data associated with a particular resource consumption node is anomalous.

The enhanced dynamic range RF pulse measurement system accepts an RF source for spectral analysis. The system includes an RF splitter accepting the RF source under analysis as input. The split output connects to identical precision timing insertion units (TIU) 1 and 2, each time tagging its respective RF signal stream. TIU 1 feeds a first real-time spectrum analyzer (RSA 1) set for strong signals at an exemplary 3.00 dBm reference level. TIU 2 feeds a second real-time spectrum analyzer (RSA 2) set for weak signals at an exemplary 15.00 dBm reference level. Outputs of RSA 1 and RSA 2 are then fed to a multi-channel recorder which records the respective time tagged RF signal streams. For each signal stream real-time PDW processing is performed. Output of the recorder feeds a workstation that for any given time tag selects and processes the channel having the highest quality signal.

A digital measurement system includes an oscillator, a mixer, and a controller coupled to each other. The oscillator provides a reference signal having a second frequency. The mixer generates a down-converted signal based on the output signal and the reference signal. The controller then determines a characteristic of the output signal (e.g., frequency or phase) based on the down-converted signal. An analog measurement system includes a filter having a center frequency, a rectifier, and a controller. The filter filters the output signal and the rectifier rectifies the filtered signal. The controller samples the rectified signal and determines a characteristic of the output signal based on the level of the rectified signal. The reference signal controller may adjust a characteristic of the output signal based on the determined frequency and/or phase of the output signal.

A system and method for tuning a transformer is provided. A transformer fixture may connect a switching network to a plurality of inductors of a transformer. At least one computing device may calculate a target number of turns for a primary coil and a secondary coil of the transformer based on a frequency response of the transformer. The switching network may connect the inductors of the transformer together in a pattern that results in the primary coil and secondary coil having the target number of turns.

A system and method for tuning a transformer is provided. A transformer fixture may connect a switching network to a plurality of inductors of a transformer. At least one computing device may calculate a target number of turns for a primary coil and a secondary coil of the transformer based on a frequency response of the transformer. The switching network may connect the inductors of the transformer together in a pattern that results in the primary coil and secondary coil having the target number of turns.

A system and method for tuning a transformer is provided. A transformer fixture may connect a switching network to a plurality of inductors of a transformer. At least one computing device may calculate a target number of turns for a primary coil and a secondary coil of the transformer based on a frequency response of the transformer. The switching network may connect the inductors of the transformer together in a pattern that results in the primary coil and secondary coil having the target number of turns.

A system and method for tuning a transformer is provided. A transformer fixture may connect a switching network to a plurality of inductors of a transformer. At least one computing device may calculate a target number of turns for a primary coil and a secondary coil of the transformer based on a frequency response of the transformer. The switching network may connect the inductors of the transformer together in a pattern that results in the primary coil and secondary coil having the target number of turns.

A method for single-phase islanding detection in a three-phase electricity network, can include supplying power into a three-phase electricity network (EN) by a power supply assembly (PSA), the electricity network (EN) having a network voltage, and providing a stimulus signal into a positive sequence electric quantity of the electricity network, the positive sequence electric quantity being current, power or a derived quantity thereof. A magnitude and/or a rate of change of an indicative element of a negative sequence component of the network voltage is monitored, a frequency domain of the indicative element including a frequency corresponding to the stimulus signal. A single phase islanding condition is detected in the electricity network (EN) if the magnitude and/or rate of change of the indicative element exceeds a predetermined limit value.