The University of Hongkong

Versitech, Inc.

Shu Yuen Hui

Siew Chong Tan

Chi Kwan Lee

Sinan Li

Ting Leung Albert Lee

Wenxing Zhong

Deyan Lin

Yue Guo

Jiayang Wu

Wenlong Qi

Jian Yin

Ting Leung Lee

A power converter circuit includes: a direct current (DC) side; a first passive network; a first current switching network; at least one floating capacitor; a second current switching network; a second passive network; and an alternating current (AC) side. The first passive network is connected between the DC side and the first current switching network for linking the DC side and the first current switching network. The first current switching network comprises at least four serially linked switches for switching the power converter circuit between switching cycles. The at least one floating capacitor is connected to the first current switching network. The second current switching network comprises two pairs of switches for providing an interface between the first current switching network and the second passive network. The second passive network is connected between the second current switching network and the AC side.

AC-to-DC and DC-to-AC power conversion

Disclosed is an AC-AC power converter with multiple AC voltage output branches. The AC-AC power converter is bridgeless and contains only one power stage. The AC-AC power converter consists of only one inductor for power conversion and provides a current source for successively feeding multiple output branches one at a time. Each output branch can be selected by the corresponding switch and its resonant circuit turns the input current source into an AC power source.

Bridgeless single-stage single-inductor multiple-output (SIMO) AC-AC converter topology

Wireless power transfer systems and methods are provided. No wireless communication system is necessary feedback output information from the receiver side to the transmitter side. Nor is any knowledge of the mutual coupling or mutual inductance between the transmitter side and the receiver side required. A system can include an intermediate capacitor in the receiver circuit as a power flow indicator and hysteresis on-off switching actions of a decoupling power switch in the receiver circuit to regulate the DC voltage of the intermediate capacitor (for voltage-control) and the load current (for current-control) at a rated value within a narrow tolerance band. The turn-on and turn-off times of the decoupling switch in the receiver circuit can be detected in the transmitter circuit from, for example, the primary winding current or voltage. This can be used to meet the power demand in the receiver circuit dynamically.

Transmitter-side control of wireless power transfer systems without using mutual coupling information or wireless feedback

A method for identifying impedance related parameters in a wireless power transfer (WPT) system including n coils is disclosed. Said method includes determining optimum values of the impedance related parameters based on a set of measured input impedance by applying an evolutionary algorithm to solve optimum solutions. Wherein the set of measured input impedance includes an input impedance vector {right arrow over (Z)}=(Z, Z, . . . , Z, Z), each input impedance in the vector (Z) measured at different frequencies f, (k=1, 2, . . . m); and the impedance related parameters includes drepresenting a distance between the l-th coil and the l+1 coil (l=1, 2, . . . n&#x2212;1) and Crepresenting a capacitance of the capacitor connected to the i-th coil (i=1, 2, . . . n).

Methods for parameter identification, load monitoring and output power control in wireless power transfer systems

A single-stage AC-DC single-inductor multiple-output (SIMO) LED driver uses a single inductor (L) to drive multiple independent LED strings (-) with Power Factor Correction (PFC). The driver uses a diode bridge () to achieve initial AC to DC conversion. The output of the bridge () is provided to a buck converter whose output is shared with multiple LED strings by a time division multiplex circuit. Feedback is used to separately control the current supplied to each LED string by using a separate reference for each string and controlling the width of the current pulse provided to a string. Current balancing in every LED string can be achieved with the same voltage reference without the need for additional circuitry.

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Hong Kong, China

Shu Yuen Hui