Disclosed is a method and apparatus for determining mutual inductance for effective wireless power transmission. The apparatus includes a resonance circuit unit including at least one transmission resonance circuit and at least one reception resonance circuit and configured to transmit power to the reception resonance circuit using power supplied to the transmission resonance circuit, and a controller configured to determine a mutual inductance value related to a transmission resonance circuit to which power is supplied when power is supplied only to any one transmission resonance circuit of the at least one transmission resonance circuit and power supply to another transmission resonance circuit is blocked, and to determine a sign of mutual inductance related to a transmission resonance circuit to which power is supplied when power is supplied only to a reference transmission resonance circuit and any one transmission resonance circuit except for the reference transmission resonance circuit.

A system for determining electrical characteristics of an electric load can comprise a signal modulation circuit that can include a first integral controller configured to control AC reference voltage based on a requested maximum AC current and an estimated maximum AC current, a second integral controller configured to control DC reference voltage based on a requested DC current and an estimated DC current, a signal demodulation circuit including an AC current estimation circuit configured to generate the estimated maximum AC current for the signal modulation circuit, a DC current estimation circuit configured to generate the estimated DC current for the signal modulation circuit, and a resistance and inductance (RL) estimation circuit configured to determine inductance of the electric load based on the estimated maximum AC current and phase shift, wherein the estimated maximum AC current is a value lower than a DC offset current value.

A method for detecting the presence of a receiver in an inductively coupled power transfer system having a transmitter and receiver. The method includes switching on a transmitter converter at a first frequency, measuring the inrush current and determining whether there is a receiver present. In another method, the inrush current is measured for a range of transmitter frequencies, and the variation in current is used to determine where there is a receiver present. In another method, the inrush current is measured when there is a change in voltage in the transmitter, and the variation in current is used to determine where there is a receiver present. In another method, the current supplied to the transmitter converter is measured over two transmitter frequencies, and the variation in current is used to determine where there is a receiver present. In another method, the current supplied to the transmitter converter is measured over two transmitter voltages, and the variation in current is used to determine where there is a receiver present.

Foreign object detection for wireless power transmitters and related systems, methods, and devices are disclosed. A controller for a wireless power transmitter includes a processing core and an analog to digital converter configured to sample at least one of a coil voltage potential and a coil current of a transmit coil. The processing core is configured to determine an expected reference Q-factor value responsive to the at least one of the sampled coil voltage potential and the sampled coil current, and compare the expected reference Q-factor value to a reference Q-factor value received from a wireless power receiver. The processing core is further configured to determine that a foreign object is detected proximate to the transmit coil responsive to a comparison of the expected Q-factor value to the reference Q-factor value received from the wireless power receiver.

Induction cooktops and operational methods are provided herein. A method of determining material composition of cookware on an induction cooktop can include determining that a piece of cookware is on the induction cooktop, inducing a current within the piece of cookware with an induction coil of the induction cooktop, and obtaining a peak induction coil current, a smoothed input line current, and a phase shift of current flowing in the induction coil. The method can further include comparing the peak induction coil current, the smoothed input line current, and the phase shift each to a set of predetermined ranges, and determining candidate material compositions for the cookware based on the comparing of each of the peak induction coil current, the smoothed input line current, and the phase shift.

A method for controlling one or more parameters of an amplifier system may include receiving an indication of a physical quantity associated with the amplifier system, determining one or more parameters of the amplifier system in response to the indication, and causing the amplifier system to operate in accordance with the one or more parameters.

Object detection for wireless power transmitters and related systems, methods, and devices are disclosed. A controller for a wireless power transmitter is configured to receive a measurement voltage potential responsive to a tank circuit signal at a tank circuit, provide an alternating current (AC) signal to each of the plurality of transmit coils one at a time, and determine at least one of a resonant frequency and a quality factor (Q-factor) of the tank circuit responsive to each selected transmit coil of the plurality of transmit coils. The controller is also configured to select a transmit coil to use to transmit wireless power to a receive coil of a wireless power receiver responsive to the determined at least one of the resonant frequency and the Q-factor for each transmit coil of the plurality of transmit coils.

A method for determining a sensor coil inductance of an eddy current sensor using an LC oscillator circuit includes determining the sensor coil inductance via integration, as a function of an oscillation frequency and a resonance capacitance of the LC oscillator circuit. The method further includes detuning, at least once, the oscillation frequency during the integration.

A method for controlling a multiphase synchronous motor, for a motor flux vector includes setting a first winding of the motor to a floating state in which the first winding is electrically floating; setting a voltage across a second winding of the motor for a first period; receiving first voltage samples associated with the first winding in the first period; setting the voltage across the second winding to a second period, in which the first period and the second period are periods of one or more pulse width modulation cycles, in which a polarity of the voltage across the second winding in the second period is opposite to a polarity of the voltage across the second winding in the first period; receiving second voltage samples associated with the first winding in the second period; and determining a position of the rotor based on the first and second voltage samples.

A measurement method using an inductive proximity sensor connected to a cable, the measurement method including the following steps: applying to the cable an excitation voltage at a known reference frequency; acquiring a measurement voltage representative of the excitation current that flows in the cable and in the sensor under the effect of the excitation voltage; multiplying the measurement voltage both by a first reference signal in order to obtain a first measurement signal and also by a second reference signal in order to obtain a second measurement signal; using the first measurement signal and the second measurement signal to evaluate a measurement impedance representative of the impedance of the sensor and of the cable; using the measurement impedance to estimate the inductance of the sensor or the impedance of the sensor; and comparing the inductance of the sensor or the impedance of the sensor with a predefined detection threshold in order to obtain proximity information.