The University of Hong Kong

Versitech, Inc.

Other

The Hong Kong Polytechnic University

Siew Chong Tan

Shu Yuen Ron Hui

Sinan Li

Ting Leung Albert Lee

Shu Yuen Hui

Song Xiong

Chi Kwan Lee

Yue Guo

Ka Hong Loo

Yuk Ming Lai

Chi Kong Michael Tse

Wenlong Qi

Weijian Jin

Huan Ting Chen

Wai Keung Lun

Kwan Tat Mok

Jiayang Wu

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

A power converter comprising one or more switch blocks. Each switch block has: a plurality of switch-pairs each having two switches connected in series to each other; a plurality of primary nodes each interconnecting the switches in a respective switch-pair; and a plurality of secondary nodes, each switch-pair being connected in series to an adjacent switch-pair through a said secondary node to form a serial chain of switch-pairs, the secondary nodes including a secondary node at one end of said serial chain and a secondary node at another end of said serial chain. Each adjacent pair of said primary nodes is connectable to a flying capacitor. Each pair of said secondary nodes is connectable to one or more of the following: one or more bypass capacitors, and one or more other said switch blocks. The power converter further comprises a first terminal formed by any two of the secondary nodes in any one of the switch blocks, and a second terminal formed by any two of the secondary nodes in any one of the switch blocks.

Plural stages switching capacitor converter

A system and a control method for generating multiple independent alternating current (AC) voltages from a direct current (DC) voltage source in a single-inductor multiple-output (SIMO) inverter are disclosed. The system comprising: a DC voltage source () for providing electrical energy; a front-stage DC-DC power converter () comprising exactly one inductor as an energy storage element for power conversion and a main switching element; a plurality of selectable output branches (), wherein each output branch comprises an output selection switch (), a resonant tank (), and a transmitter coil (), wherein the resonant tank converts output power of the DC-DC power converter into AC power for feeding the transmitter coil; and a controller () for determining ON/OFF states of the main switching element and the output selection switch of each of the output branches. The system and the method can provide simple, compact, scalable, and low-cost solutions by employing only a single inductor to drive multiple independent transmitting coils.

Single-stage single-inductor multiple-output (SIMO) inverter topology with precise and independent amplitude control for each AC output

Switched capacitor (SC) converters with excellent voltage regulation, high conversion efficiency, and good suitability fora wide range of applications are provided. An SC converter can include at least two SC sub-circuits, and at least one of these SC sub-circuits can be of variable gain. One SC sub-circuit can convert the input voltage of the SC converter to an output voltage close to the desired output voltage value for the SC converter, and another SC sub-circuit having variable gain can convert the input voltage to an output voltage with a high resolution of small discrete voltage steps.

High-efficiency switched-capacitor power supplies and methods

In many power electronics systems, there is an intermediate DC-link stage for facilitating the power processing of different sources to their loads. A device called a plug-and-play ripple pacifier (RP) directly plugged into the DC-link, and actively removes undesired DC-link ripple, thereby eliminating the reliance on electrolytes capacitors for stabilizing the system and remove ripple. Importantly, the use of this device is non-invasive to the operation of its host systems, and requires no modification of existing hardware. It is suitable for the protection of DC utilities/systems and can also be used as a direct replacement of ripple-canceling E-Caps in power converters device.

Plug-and-play ripple pacifier for DC voltage links in power electronics systems and DC power grids

A power controller for an AC power converter connected in series with a load and receiving power from or delivering power to a power source, the power controller comprising: a radial control block controlling a radial component of an electrical parameter of the AC power converter; and a chordal control block controlling a chordal component of the electrical parameter of the AC power converter. Also provided is a power system comprising one or more loads each connected in series to a power converter each controlled by a power controller as described above. There is also provided a method of controlling an AC power converter connected in series with a load and receiving power from a power source, the method comprising: controlling a radial component of an electrical parameter of the AC power converter; and controlling a chordal component of the electrical parameter of the AC power converter.

Power controller and power control method

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.

AC-DC single-inductor multiple-output LED drivers

A correlated color temperature control system () for a LED lighting system () having at least two LED sources () with different correlated color temperatures. The LED lighting system () has a combined correlated color temperature resulting from the combination of the different correlated color temperatures of the at least two LED sources (), and a combined luminous flux resulting from the combination of the luminous fluxes of the at least two LED sources (), with each LED source being supplied with a supply current. The correlated color temperature control system () comprises a controller () to independently control one or both of the duty cycle and amplitude of each supply current, the duty cycle or amplitude of each supply current being varied by the controller in a non-linear relationship with the duty cycle or amplitude of at least one other of the supply currents, to generate a desired combined correlated color temperature for the LED lighting system () at a desired combined luminous flux for the LED lighting system (). An associated method is also provided.

Correlated colour temperature control system and method

A driving method for improving luminous efficacy of a light emitting diode (LED), the method comprising: periodically switching a DC current supplied to the LED between a high current level land a low current level l, the low current level lbeing fixed at zero or raised above zero to produce a DC offset; and maintaining an average current at a first valueby adjusting the duty cycle acting on the high current level land any one from the grouping consisting of: adjusting the high current level land adjusting the low current level l, and adjusting the high current level lor adjusting the low current level l.

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Hong Kong, China

Siew Chong Tan