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 system may include an array of sensor elements, the array of sensor elements each comprising a first type of passive reactive element, a second type of passive reactive element electrically coupled to the array of sensor elements, a driver configured to drive the array of sensor elements and the second type of passive reactive element, and control circuitry configured to control enabling and disabling of individual sensor elements of the array of sensor elements to ensure no more than one of the array of sensor elements is enabled at a time such that when one of the array of sensor elements is enabled, the one of the array of sensor elements and the second type of passive reactive element together operate as a resonant sensor.

Provided are systems that includes an a induction heating circuit and at least one processor programmed or configured to generate each line of a plurality of lines, where each line comprises a graphical representation of phase value versus frequency of a signal with which the induction heating circuit is driven, determine a line of the plurality of lines that has a maximum slope, determine an average frequency of the line having the maximum slope, determine a phase value corresponding to the average frequency of the line having the maximum slope, determine a time delay, determine a self-resonant frequency (SRF) value of the induction heating circuit based on the time delay, and determine a characteristic of the induction heating circuit based on the resonant frequency value. Methods and computer program products are also disclosed.

Techniques are described for a non-invasive detection of a health condition of an organ. In an example, the electrical conductivity of the organ reflects the organ's health of. An inductive damping sensor can be used to detect the organ's electrical conductivity and, thus, its health. The inductive damping sensor can be placed in proximity of the organ such as the organ is within the magnetic field generated based on a coil of the inductive damping sensor. The conductivity of the organ impacts the inductance and the resistance of the coil. Hence, the inductance and/or resistance of the coil can be measured, where the measurements can be associated with the health of the organ.

Various embodiments include a DC switch for disconnecting a DC line. The switch may include: a power semiconductor switch arranged in a current path of the DC line; a first sensor for measuring the input and output voltages; a second sensor for measuring the current flowing through the DC line; and a controller for the power semiconductor switch. The control device is configured to: switch on the DC switch for a first time period; determine the input voltage present; determine the output voltage present at the end of the first time period; determine the current intensity present at the end of the first time period; and determine an inductance and/or capacitance from the determined values.

The present invention concerns a method and a device for determining a position of a rotor of a three-phase motor using a FOC system. The invention: —determines, by a proportional-integral controller, a first control voltage vector at a first instant, —transforms the first control voltage vector using an inverse Park transform, —sums the transformed first control voltage vector to a regular polygonal voltage pattern applied during a given duration, —performs a PWM from the sum of the transformed first control voltage vector and the regular polygonal voltage pattern, —controls the motor with the pulse-width modulation, —measures the current at each phase of the motor, —estimates the position of the rotor from the measured currents and from the regular polygonal voltage pattern, —determines, at a second instant, a second control voltage vector from the measured currents and from the estimated position.

A first-order resistor-inductor (RL) circuit is allowed to alternate a direct-current excitation response and a zero-input response so that a direct-current magnetic field generated by an inductor magnetizing coil changes alternately in magnetic field intensity with a change in magnitude of current. After a testing object is placed in the direct-current magnetic field changing alternately in magnetic field intensity, the testing object is magnetized and also causes a change in inductance of the magnetic field. Whether a change occurs in electromagnetic properties of the testing object can be determined and detected by detecting the inductance change of the magnetizing coil or detecting electrical characteristic change caused by the inductance change of the magnetizing coil, thereby determining whether quality defects such as steel wire cracks and wire breakage in a steel wire rope occur. Alternatively, the properties such as a sectional area or a zinc layer thickness can be analyzed.

An apparatus for detecting a stacking direction of internal electrodes of a multilayer capacitor includes a capacitor moving unit having a supply unit in which a plurality of multilayer capacitors are continuously supplied ad moving the supplied multilayer capacitors in one direction, a sensor unit including a coil, installed on the capacitor moving unit, and detecting inductance of the coil when each of the multilayer capacitors approaches the coil to determine a stacking direction of internal electrodes of the multilayer capacitor based on the detected inductance of the coil, and a separating unit installed on the capacitor moving unit and separating a multilayer capacitor selected as an unsuitable multilayer capacitor by the sensor unit.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor with a plurality of driving signals, each driving signal of the plurality of driving signals having a respective driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure a first value of a physical quantity associated with the resistive-inductive-capacitive sensor in response to a first driving signal of the plurality of driving signals, wherein the first driving signal has a first driving frequency; measure a second value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to a second driving signal of the plurality of driving signals, wherein the second driving signal has a second driving frequency; measure a third value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the first driving signal; measure a fourth value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the second driving signal; determine a first difference between the third value and the first value; determine a second difference between the fourth value and the second value; and based on the first difference and the second difference, determine if a change in a resonant property of the resistive-inductive-capacitive sensor has occurred, and determine if a change in a quality factor of the resistive-inductive-capacitive sensor has occurred.

A circuit for an inductive conductivity sensor comprises: a secondary coil having a first coil terminal and a second coil terminal, a switch having a first switch terminal, a second switch terminal, a third switch terminal, a first potential terminal, and a control unit having a first control terminal and a second control terminal, wherein the first coil terminal is connected to the first control terminal and the second coil terminal is connected to the first switch terminal, wherein the second switch terminal is connected to the first potential terminal and the third switch terminal is connected to the second control terminal.