An interleaved LLC converter arrangement includes two or more LLC converters for transferring power from an input side to an output side, wherein the two or more LLC converters include a first LLC converter and a second LLC converter connected in parallel on the input side and on the output side and wherein each LLC converter includes a bridge inverter at the input side. For balancing the power transfer among the LLC converters if for example the second LLC converter transfers more power from the input side to the output side than the first LLC converter, each leg of the bridge of the bridge inverter of the first LLC converter is operated with a duty cycle of 0.5 and at least one leg of the bridge of the bridge inverter of the second LLC converter is operated with a duty cycle different from 0.5.

An object of the present invention is to suppress deterioration in detection accuracy during power feeding in the detection of the metallic foreign object using the antenna coil. A metallic foreign object detector includes: an antenna coil; a capacitor that constitutes a resonance circuit RC together with the antenna coil; a power supply that applies voltage to the resonance circuit to generate a vibration signal in the resonance circuit; a determination circuit that determines the presence/absence of a metallic foreign object based on the waveform of the vibration signal; a resonance capacitor switch inserted into the resonance circuit; and a control circuit that controls the open/close state of the resonance capacitor switch. The control circuit brings the resonance capacitor switch into a closed state responding to the power supply starting application of voltage to the resonance circuit.

The invention relates to an inductive power transmission with a resonant circuit, the resonant circuit including a transmitting/receiving coil or a transmitting and receiving coil for transmitting and/or receiving electromagnetic energy, a coupling capacitor, a tuning capacitor, and a switching device, wherein the switching device is connected in series to the coupling capacitor and the tuning capacitor, and wherein, furthermore, the switching device is designed to activate and/or disconnect a signal generator and to modify a quality factor or to modify the resonance frequency of the resonant circuit.

A power converter apparatus is provided with: a plurality of leg circuits, each including two switch circuits connected in series between input terminals; a transformer including a primary winding and a secondary winding, the primary winding having a first terminal and a second terminal; and at least one capacitor. The at least one capacitor is connected between the first terminal or the second terminal of the primary winding of the transformer, and a node between the two switch circuits in at least one leg circuit among the plurality of leg circuits. The first terminal of the primary winding of the transformer is connected to at least two nodes between the switch circuits in at least two first leg circuits among the plurality of leg circuits, via at least two first circuit portions having at least one of capacitances and inductances different from each other, respectively.

A resonant converter and a manufacturing method of a transformer thereof are provided. The resonant converter includes a full bridge circuit, an element, a first branch circuit, a second branch circuit and a secondary winding. The full bridge circuit includes a first node and a second node. The element includes an inductor or a capacitor. The first branch circuit includes a first primary winding. The second branch circuit includes a second primary winding, and the first and second primary windings have the same turn number. The transformer is constructed by the first and second primary windings and the secondary winding. The first branch circuit, the element and the second branch circuit are sequentially coupled in series between the first and second nodes. The first branch circuit and the second branch circuit are symmetrically located with respect to the element. The first and second branch circuits have the same impedance.

An induction heating device using a resonance circuit method and a control method thereof that are capable of preventing occurrence of overcurrent even when an object is moved are provided. The induction heating device for heating an object includes a resonance circuit including a heating coil and a condenser, an inverter configured to supply power to the resonance circuit, a detector configure to detect a value related to a movement of the object, and at least one processor configured to identify whether the object is moved based on the value detected by the detector, and upon determining that the object is moved, lower a driving frequency of the inverter and an output of the inverter.

A primary unit for an inductive charging system configured to transmit energy from the primary unit to a secondary unit via a magnetic field includes a primary coil, which is configured to generate the magnetic field in response to a coil current through the primary coil. The primary unit also has a first inverter, which is coupled to the primary coil via a first capacitor and which is configured to charge and/or discharge the first capacitor based on a first input voltage; and a second inverter, which is coupled to the primary coil via a second capacitor and which is configured to charge and/or discharge the second capacitor based on a second input voltage. The primary unit has a control unit, which is configured to identify capacitance information with respect to an effective capacitance of a primary resonant circuit of the primary unit, and to actuate the first inverter and the second inverter depending on the capacitance information in order to effect the coil current through the primary coil.

An LLCC Secondary Overtone Resonant (LLCC-SOR) power converter obtains dramatically higher efficiency with light loads by providing a resonance in the transformer secondary that is approximately tuned to an odd order overtone of the upper primary switching frequency, an upper frequency limit of the primary switching frequency, and a secondary duty cycle control that engages once the upper primary switching frequency limit is reached. The transformer circuit resonates in an LLCC-SOR mode that regulates the output voltage when the maximum frequency limit is reached. In operation, the gain of the resonant circuit is raised above its regulation point under light loads, forcing the controller into duty cycle mode. The secondary current completes an odd number of oscillations per single oscillation of the primary current, and the primary current returns to near zero after each switching transition. Also, a zero-voltage switching condition is maintained on the primary switch.

A resonant converter and a manufacturing method of a transformer thereof are provided. The resonant converter includes a full bridge circuit, an element, a first branch circuit, a second branch circuit and a secondary winding. The full bridge circuit includes a first node and a second node. The element includes an inductor or a capacitor. The first branch circuit includes a first primary winding. The second branch circuit includes a second primary winding, and the first and second primary windings have the same turn number. The transformer is constructed by the first and second primary windings and the secondary winding. The first branch circuit, the element and the second branch circuit are sequentially coupled in series between the first and second nodes. The first branch circuit and the second branch circuit are symmetrically located with respect to the element. The first and second branch circuits have the same impedance.

A method of controlling highly regulated power and frequency from a high frequency power supply system to provide a highly regulated power and frequency to a workpiece load where the highly regulated power and frequency can be independent of the workpiece load characteristics by inverter switching control and an inverter output impedance adjusting and frequency control network that can include precision variable reactor pairs with a geometrically-shaped moveable insert core section and a stationary split-bus section with a complementary geometrically-shaped split bus section and a split electric terminal bus section where the insert core section can be moved relative to the stationary split-bus section to vary the inductance of the variable reactors.