In this paper, a high-efficiency high power density LLC resonant converter with a matrix transformer is proposed. A matrix transformer can help reduce leakage inductance and the ac resistance of windings so that the flux cancellation method can then be utilized to reduce core size and loss. Synchronous rectifier (SR) devices and output capacitors are integrated into the secondary windings to eliminate termination-related winding losses, via loss and reduce leakage inductance. A 1 MHz 390 V/12 V 1 kW LLC resonant converter prototype is built to verify the proposed structure. The efficiency can reach as high as 95.4%, and the power density of the power stage is around 830 W/in3.

LLC Resonant Converter With Matrix Transformer

Paper presents a three level soft switching LLC series resonant DC/DC converter. ZVS is achieved for each main switch without any auxiliary circuit. Voltage stress of each main switch is half of input voltage. ZCS is achieved for rectifier diodes. Wide input/output range can be achieved under low frequency range because of two-stage resonance. Only one magnetic component is needed in this converter. Efficiency is higher in high line input, so this converter is fit for power products with hold up time requirement. The principle of operation and the characteristics of the new converter are analyzed and verified on a 500 V/spl sim/700 V input 54 V/10 A output experimental prototype, whose efficiency is 94.1% at rating condition.

Three level LLC series resonant DC/DC converter

In wireless power transfer with applying magnetic resonance therein, for suppressing deterioration of transfer efficiency, with lessening fluctuation of the resonance frequency when a distance between coils is close to, coils are so position that a supply-side power supply coil 101 and a load-side power supply coil 102 are inserted between a supply-side magnetic resonance coil 1 and a load-side magnetic resonance coil 2.

Wireless power transfer system and a load apparatus in the same wireless power transfer system

Methods and structures for constructing a magnetic core of a coupled inductor. The method provides for constructing N-phase coupled inductors as both single and scalable magnetic structures, where N is an integer greater than 1. The method additionally describes how such a construction of the magnetic core may enhance the benefits of using the scalable N-phase coupled inductor. The first and second magnetic cores may be formed into shapes that, when coupled together, may form a single scalable magnetic core. For example, the cores can be fashioned into shapes such as a U, an I, an H, a ring, a rectangle, and a comb, that cooperatively form the single magnetic core.

Method For Making Magnetic Components With M-Phase Coupling, And Related Inductor Structures

A switching power supply unit of the present invention a timing generating circuit ( 121 ) which receives a first control signal formed by a rectifier-transistor driving circuit ( 104 ), forms a second control signal based on the first control signal, and supplies the second control signal to a control electrode of the rectifier transistor ( 113 ). The first control signal is synchronized with the switching operation of a half-bridge circuit ( 102 ), and the second control signal exceeds a threshold voltage of a rectifier transistor ( 113 ) at a timing substantially equal to the timing that one edge of the first control signal is generated and falls below the threshold voltage of the rectifier transistor ( 113 ) at a timing earlier by predetermined time than the timing that the other edge of the first control signal is generated.

Switching power supply unit

The present invention discloses a DC-to-DC converter. The DC-to-DC converter includes a square wave generator for generating a sequence of output voltages having a waveform of square wave. The DC-to-DC converter further includes a resonant tank connected to the square wave generator comprising a series capacitor connected to a series inductor and a parallel inductor. The DC-to-DC converter further includes a transformer having a primary side connected in series with the series inductor and connected in parallel to the parallel inductor. The transformer further includes a secondary side for connecting to a rectifying circuit for providing a rectified DC voltage to an output load circuit. The series capacitor functioning with the series inductor to provide a first characteristic resonant frequency represented by ƒ s , and the series capacitor functioning with the series inductor and the parallel inductor to provide a second characteristic resonant frequency represented by ƒ m wherein ƒ s >ƒ m . The converter runs at variable frequency switching to perform output regulation. The converter features high conversion efficiency at high input operation by switching at frequency between the first and second characteristic resonant frequency. In a preferred embodiment, the parallel inductor is integrated to transformer as primary magnetizing inductor and in further the series inductor may also be integrated into transformer.

LLC series resonant DC-to-DC converter

An asymmetrical full bridge DC-to-DC converter comprises an asymmetrical full bridge circuit which includes main switches and auxiliary switches, a capacitor connected in series to the branch circuit of the auxiliary switches, and a transformer having a primary winding and a secondary winding. The primary winding of transformer is connected to the common point of each leg of the full bridge. A rectification circuit is connected at the secondary winding of the transformer to obtain dc voltage output. In operation, an asymmetrical control method is applied for these main switches and auxiliary switches. Main switches and auxiliary switches turn on and turn off compensatively. A linear control characteristic of output voltage to switching duty cycle and an optimal reset of the transformer core is achieved by this invention.

Asymmetrical full bridge dc-to-dc converter

The invention discloses a DC/DC converter. The DC/DC converter includes a square wave generator, which is used to output a series of voltage in form of square wave. The said square wave generator includes a serial capacitor which is connected to serial inductor and parallel inductor. Primary side of transformer is cascaded to a serial inductor in the DC/DC converter, then connected to an inductorin parallel. Secondary side of transformer is connected to a rectification circuit so as to provide a rectified DC voltage for output load circuit. The first characteristic resonance frequency of theserial capacitor and the serial inductor are expressed as fs. The second characteristic resonance frequency of the serial capacitor and the serial inductor as well as parallel inductor are expressed as fn where fs>fn. Switching of variable frequency in the converter carries out the output adjustment. Based on frequency switching between first and second characteristic resonance frequency, the converter realizes high conversion efficiency when working under high input voltage.

DC/DC converter with LLC serial resonance

A resonant reset dual switch forward converter is disclosed. The resonant reset dual switch forward converter includes an input for accepting a DC voltage; a transformer having a primary winding and a secondary winding; a first and a second switch connected in series with the primary winding of the transformer for periodically connecting the input to the primary winding; a resonant capacitor for resetting the transformer during the OFF time of the first and second switches; and an auxiliary switch remaining OFF during the ON time of the first and second switches, and connecting the primary winding to the resonant capacitor during the OFF time of the first and second switches. The resonant reset dual switch forward converter provides a switching duty cycle greater than 50%, obtains a zero-voltage-switching condition for the first and second switches, and maintains the voltage stress of the f first and second switches around the input voltage.

Resonant reset dual switch forward DC-to-DC converter

An active clamped-mode DC-to-DC converter with synchronous rectifiers and a combined transformer-inductor device is provided. The power converter includes a combined transformer-inductor device having a primary winding, a secondary winding, and an auxiliary winding where the primary and the secondary windings perform a transformer function and the auxiliary winding performs an output filter function, a switching circuit for periodically providing a positive voltage to the primary winding and a negative voltage to reset the primary winding, and a synchronous rectification circuit connected for enabling conduction from the secondary winding to an output port in which the auxiliary winding is coupled between the output port and the synchronous rectification circuit for providing an inductance to filter an output signal.

Yilei Gu

Papers

LLC series resonant DC-to-DC converter

Asymmetrical full bridge dc-to-dc converter

DC/DC converter with LLC serial resonance

Resonant reset dual switch forward DC-to-DC converter

Combined transformer-inductor device for application to DC-to-DC converter with synchronous rectifier