The present invention relates to a wireless power control method and device for wireless charging, and the wireless power control method of a wireless power transmitter according to an embodiment of the present invention may comprise: a step of receiving, from a wireless power receiver, a first feedback signal requesting power control; a step of determining the intensity of a first transmission power on the basis of the first feedback signal; a step of determining an inverter type and a power control method which correspond to the determined intensity of the first transmission power; a step of activating an inverter corresponding to the determined inverter type; and a step of controlling the intensity of alternating current power outputted from the inverter, by using the determined power control method.

A display apparatus is provided. The display apparatus includes a plurality of display modules, each of the plurality of display modules including a first electrode plate provided on a back surface of the display module; a frame including a plurality of areas to which the plurality of display modules are respectively mounted; a power supply module including a second electrode plate, the second electrode plate being disposed on a back surface of the frame and adjacent to the first electrode plate. The power supply module is configured to provide an alternating current (AC) power received from an external apparatus to each of the plurality of display modules, and each of the plurality of display modules is configured to convert the AC power to a direct current (DC) power.

A resonant power conversion device includes: a main circuit provided with a semiconductor switch, a capacitor and an inductor connected in series or parallel to the semiconductor switch; and a drive circuit configured to drive the switching element. The switching element enters an off-state or an on-state depending on a control voltage input to a gate terminal, and the drive circuit includes two or more types of control voltages, as a control voltage at which the switching element enters an off-state.

Device for providing a magnetic field for transfer of energy A device for providing an inductive power transfer (110, 210). The device comprises a switching power supply (VI) for providing electrical power to the device and an inductor coil (140). The device further comprises a resonance adjustment module (110) for adjusting the resonance frequency of the circuit comprising the inductor coil and a control circuit arranged to control the module such that the resonance frequency is substantially constant. The mutual and leakage inductance of a transmitter coil and of a receiver coil change if the receiver coil is placed above the transmitter coil. The circuit is utilised for inductive power transfer to a vehicle, possibly in a parking space.

The present disclosure includes by controlling at least either one of a switching frequency of a switching element (S) or a duty ratio indicating an ON period of the switching element, securing delay time from voltage at both ends of the switching element reaches zero voltage by resonance of the resonant circuit (L.sub.0, C.sub.0) in an OFF state of the switching element until the switching element is turned on, and turning on the switching element within the delay time.

A control method of controlling a resonance type power conversion device including a voltage resonance circuit is provided. The voltage resonance circuit comprising, a choke coil connected to input power supply, a first switching element connected to the choke coil, a capacitor connected in parallel to the first switching element, and a resonance circuit connected between a connection point and an output terminal, the connection point being a point at which the choke coil and the first switching element are connected. The control method comprising, detecting a polarity of current flowing through parallel circuit connected in parallel to the first switching element by using a sensor included in the voltage resonance circuit; and controlling an operating condition of the first switching element depending on a polarity of the current detected by the sensor.

A method for minimizing DC capacitance of a cascade multilevel converter is provided. On the basis of balancing of capacitor voltages, the method estimates instantaneous value of the DC side capacitor voltages in a circuit through an energy conservation law, and uses a proportional resonance controller to control a grid-connected current to realize adjustment of the grid-connected current without static difference, such that the cascade multilevel converter can operate in a small capacitance mode, the system volume is greatly reduced, the system cost is reduced, the control is easy to be implemented, and the capacitor voltage is free from overshoot and the system has a better rapidity.

A contactless power supply device includes a power transmitter, and a power receiver. The power receiver includes: a resonant circuit including a receiver coil and a resonant capacitor; a rectifier circuit configured to rectify the power output from the resonant circuit; a voltage detection circuit configured to measure the output voltage from the rectifier circuit and obtain a measurement value for said output voltage; and a first communication device. The power transmitter includes: a transmitter coil; a power supply circuit including a power source and a plurality of switching elements between the power source and the transmitter coil; an auxiliary coil for electromagnetic coupling with the transmitter coil; a variable capacitance circuit configured to connect to the auxiliary coil and adjust the electrostatic charge therein; and a control circuit configured to control the electrostatic charge in the variable capacitance circuit in accordance with the measurement value for the output voltage.

A contactless power supply device includes: a power transmitter, and a power receiver configured to accept a power transmission from the power transmitter without contact; the power transmitter including a transmitter coil for supplying power to the power receiver via a receiver coil in the power receiver; a power supply circuit including a power source configured to supply direct-current power, and a plurality of switching elements connected in a full-bridge or half-bridge configuration between the power source and the transmitter coil; the plurality of switching elements switching between on and off states at a predetermined frequency to thereby convert the direct-current power supplied by the power source into alternating-current power of a predetermined frequency which is supplied to the transmitter coil; an auxiliary coil arranged to be capable of electromagnetic coupling with the transmitter coil; and a capacitive element configured for connection to the auxiliary coil.

A contactless power supply device includes: a power transmitter, and a power receiver configured to accept a power transmission from the power transmitter without contact; the power transmitter including a transmitter coil for supplying power to the power receiver via a receiver coil in the power receiver; a power supply circuit including a power source configured to supply direct-current power, and a plurality of switching elements connected in a full-bridge or half-bridge configuration between the power source and the transmitter coil; the plurality of switching elements switching between on and off states at a predetermined frequency to thereby convert the direct-current power supplied by the power source into alternating-current power of a predetermined frequency which is supplied to the transmitter coil; an auxiliary coil arranged to be capable of electromagnetic coupling with the transmitter coil; and a capacitive element configured for connection to the auxiliary coil.