The present disclosure relates to a detection circuit, an appliance, and a control method. The detection circuit includes at least a first capacitive component, a second capacitive component, a load to be detected and a detection component, where the first capacitive component is connected in series with the load to be detected to form a first branch, and the first branch is connected in parallel with a second branch including the second capacitive component. The detection component is configured to detect a first alternating current (AC) signal of the first branch and a second AC signal of the second branch, determine a first direction of the first AC signal and a second direction of the second AC signal, and determine a type of the load to be detected based on the first direction and the second direction.

A wireless charger includes a rectifier, a first filter that includes an inductor, a resonant tank circuit, and a second filter that includes a switch. The rectifier receives a drive signal from a voltage supply and generates a rectified voltage signal. The rectified voltage signal is filtered by the first filter and the filtered signal is provided to the tank circuit, which resonates to provide power wirelessly to a receiver. The switch of the second filter is connected in parallel with the inductor of the first filter. The switch is closed in order to bypass the inductor during a detection phase in which the wireless charger determines a quality factor of the tank circuit.

Various implementations described herein relate to systems and methods for determining abnormal leakage current of a capacitor by determining a number of recent leakage current values for the capacitor and determining a maximum upper limit, minimum upper limit, maximum lower limit, and minimum lower limit based on leakage current values different from the recent leakage current values. A present upper limit and a present lower limit are determined for the recent leakage current values. Abnormal leakage current is determined in response to determining that the present upper limit being greater than an upper threshold (determined based on the maximum upper limit and the minimum upper limit) or the present lower limit being less than a lower threshold (determined based on the maximum lower limit and the minimum lower limit).

Various implementations described herein relate to systems and methods for determining abnormal leakage current of a capacitor by determining a number of recent leakage current values for the capacitor and determining a maximum upper limit, minimum upper limit, maximum lower limit, and minimum lower limit based on leakage current values different from the recent leakage current values. A present upper limit and a present lower limit are determined for the recent leakage current values. Abnormal leakage current is determined in response to determining that the present upper limit being greater than an upper threshold (determined based on the maximum upper limit and the minimum upper limit) or the present lower limit being less than a lower threshold (determined based on the maximum lower limit and the minimum lower limit).

In accordance with embodiments of the present invention, a wireless power transmitter includes a transmit coil that includes a plurality of concentric coils; a switch circuit coupled to the plurality of concentric coils; a driver coupled to provide a voltage to the switch circuit; and a controller coupled to the switch circuit, the controller providing control signals to the switch circuit selecting to provide the voltage across one or more of the plurality of concentric coils depending on a Q-factor measuring in the presence of a receive coil. A method of operating a wireless power transmitter includes determining a measured Q-factor for each of a plurality of configurations of concentric transmit coils; determining a difference between each of the measured Q-factors and a standard Q-factor; and selecting one of the plurality of configurations based on the differences.

The present disclosure relates to a device comprising an inductive element and a first capacitive element series connected between a first node and a second node, a first MOS transistor connected between the first node and a third node configured to receive a reference potential, the second node being coupled directly or via a second MOS transistor to the third node, a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element, a current generator configured to provide an AC current to the fourth node, and a switch connected between the fourth node and the third node.

Various implementations described herein relate to systems and methods for determining abnormal leakage current of a capacitor by determining a number of recent leakage current values for the capacitor and determining a maximum upper limit, minimum upper limit, maximum lower limit, and minimum lower limit based on leakage current values different from the recent leakage current values. A present upper limit and a present lower limit are determined for the recent leakage current values. Abnormal leakage current is determined in response to determining that the present upper limit being greater than an upper threshold (determined based on the maximum upper limit and the minimum upper limit) or the present lower limit being less than a lower threshold (determined based on the maximum lower limit and the minimum lower limit).

The present invention relates to a foreign object detecting method, and a device and system therefor. A method for detecting a foreign object in a wireless power transmitter according to an embodiment of the present invention may comprise the steps of: when an object placed in a charging area is sensed, measuring quality factor values within an operating frequency band to find a measured peak frequency at which the maximum quality factor value is measured; storing the measured peak frequency and the measured quality factor value corresponding to the measured peak frequency; transmitting information on the type of transmitter to an identified wireless power receiver; receiving a reference quality factor value and a reference peak frequency corresponding to the type of transmitter; calculating a measured inductance by using the measured peak frequency; calculating a reference inductance by using the reference peak frequency; and detecting a foreign object by using at least one of the reference quality factor value, the reference peak frequency, and the reference inductance.

A method for determining a quality factor of a wireless charger is disclosed. The wireless charger includes an inverter, a filter, and a resonant tank circuit. The inverter receives a supply voltage and generates a PWM signal at a first node and a second node. The filter connects to the first and second nodes of the inverter to receive the PWM signal, and generates a filtered signal at a first terminal and a second terminal of a capacitor. The resonant tank circuit connects to the first and second terminals of the capacitor of the filter to receive the filtered signal, and provides wireless power at an inductor coil to a receiver. The method includes: issuing a current pulse to the resonant tank circuit; and in a Q-factor determination phase of the wireless charger, connecting the resonant tank circuit and only the capacitor of the filter in a resonance network.

Some embodiments are directed to a method for detecting harmonic pollution in an electrical distribution network carrying a three-phase current, including a step of measuring the voltages and strengths of the current, for each of said phases, at a counting point of the network; a step of calculating a first quaternion impedance corresponding to the fundamental frequency of the current; a step of calculating at least one second quaternion impedance corresponding to a harmonic frequency of the current, these impedances being calculated by converting the voltages and strengths in a two-dimensional frame of reference defined according to an angle that is dependent on said frequency in order to provide a system of two vectors of three quantities, ud, uq, uo and id, iq, io, respectively.