University of Colorado

Massachusetts Institute of Technology

Cornell University

Utah State University

Khurram K Afridi

David J Perreault

Ashish Kumar

Sreyam Sinha

Minjie Chen

Dragan Maksimovic

Steven B Leeb

Arthur Hsu Chen Chang

Brandon Regensburger

Saad Pervaiz

Zorana B Popovic

Usama Anwar

Alihossein Sepahvand

Samantha J Gunter

Regan Andrew Zane

Gregory L Plett

Robert Warren Erickson

David M Otten

Michael Scott Trimboli

Benjamin J Montgomery

Sounak Maji

Mausamjeet Khatua

Yu Ni

Juan A Santiago-Gonzalez

Curtis Serrano

Guilherme Goularte Da Silva

Chieh-Kai Chang

Danish Shahzad

Nauman Zaffar

Zoya Popovic

In one implementation, a matching network is provided comprising a pair of input terminals; a pair of output terminals; and at least two reactive components disposed between the pair of input terminals and the pair of output terminals. At least one of the reactive components comprises a coupled-inductor. In various implementations, the second reactive component can be a capacitor, and the capacitor can be at least partially realized using the parasitic capacitances of the environment. The matching network may be disposed in a capacitive wireless power transfer (WPT) system. In other implementations, inductors and coupled-inductors are further provided. In some implementations, for example, an inductor, such as but not limited to a coupled-inductor, may comprise a toroidal or semi-toroidal core comprising foil wire interleaved without notches.

Matching networks, inductors, and coupled-inductor capacitive wireless power transfer circuit and related techniques

A heterogeneous energy storage device and a method for controlling a heterogeneous energy storage device are provided. In one implementation, a heterogeneous energy storage device is provided. The heterogeneous energy storage device includes a first energy storage device, a second energy storage device and a capacitive device. The first energy storage device has a first energy capacity and a first power to energy ratio (P/E). The second energy storage device has a second total energy capacity and a second P/E ratio different from the first P/E ratio. The capacitive device is coupled in series with the first energy storage device, wherein the second energy storage device is coupled in parallel with the series combination of the capacitive device and the first energy storage device. In another implementation, a method of controlling a heterogeneous energy storage device including a first energy storage device and a second energy storage device is provided. In this implementation, the method includes: providing a capacitive device in series with the first energy storage; coupling the second energy storage device in parallel with the series combination of capacitive device and the first energy storage device, wherein the capacitive device provides DC decoupling between the first energy storage device and the second energy storage device.

Heterogeneous energy storage system and method of controlling a heterogeneous energy storage system

A high-frequency inverter architecture is provided that compensates for coupling variations in wireless power transfer (WPT) systems, while adapted to operate at a fixed frequency and maintaining high efficiency. This implementation, termed a variable compensation inverter (VCI), includes a plurality of high-frequency inverters feeding a lossless resonant network, with the inputs of the inverters fed by controllable voltages. By appropriately controlling the input voltages of the individual inverters and their relative phase-shift, the VCI can maintain near-resistive, and slightly but sufficiently inductive, loading of the inverters even as the reactance of the WPT coupler changes; hence, providing compensation while maintaining zero-voltage and near-zero-current switching. The VCI also ensures that the output power of the WPT system is maintained at a fixed level even during coupling variations.

Variable compensation inverter circuit and related techniques

A capacitive wireless charging system for use with a vehicle includes a roadway-side capacitive charging pad configured to be embedded in a roadway and to form a capacitive electrical connection with a vehicle-side capacitive charging pad for wirelessly transferring power to charge a vehicle battery when the vehicle is on the roadway, a power conditioning circuit configured to be positioned next to the roadway and to condition power received from a power source, and a plurality of conductors configured to be at least partially embedded in the roadway and to electrically connect the power conditioning circuit and the roadway-side capacitive charging pad, such that the plurality of conductors form a roadway-side matching network for the capacitive electrical connection without discrete inductors and capacitors.

Roadway embeddable capacitive wireless charging systems

In one example, an active variable reactance rectifier circuit includes an active variable reactance rectifier circuit input port and an output port. A power splitter circuit includes an input port coupled to the active variable reactance rectifier circuit input port and a pair of output ports. A first rectifier circuit includes an input port is coupled to the first power splitter circuit output port. A second rectifier circuit includes an input port coupled to the second power splitter circuit output port. A power combiner circuit includes a first input port, a second input port and an output port. The first power combiner circuit input port is coupled to the first rectifier circuit output port, the second power combiner circuit input port is coupled to the second rectifier circuit output port and the power combiner circuit output port is coupled to the active variable reactance rectifier circuit output port.

Active variable reactance rectifier circuit and related techniques

A control architecture that overcomes limitations of conventional ac-dc converters and enables bidirectional active and reactive power processing is provided. In one implementation, for example, this may be achieved through the use of unrectified sensed ac signals in the generation of the control commands for the converter. This control architecture, in this example implementation, eliminates or at least reduces zero crossing distortions in the ac current of the converter even with relatively low bandwidth controllers. The concept can be applied to different power stage topologies.

Control architecture for ac-dc and dc-ac conversion capable of bidirectional active and reactive power processing

Systems and method herein provide for energy buffering. In one embodiment, a system includes an energy buffer comprising at least two energy storage elements. Each energy storage element is operable to buffer electrical energy. The system also includes a switch module operable to charge a first of the at least two energy storage elements while discharging a second of the at least two energy storage elements, and to discharge the first energy storage element while charging the second energy storage element after charging the first energy storage element. The switched charging of the energy storage elements compensates voltage variations between the energy storage elements to increase available electrical energy from the energy buffer.

Switched energy buffering

A high performance kilowatt-scale large air-gap multi-modular capacitive wireless power transfer (WPT) system is provided for electric vehicle (EV) charging. In one particular implementation, the multi-modular system achieves high power transfer while maintaining fringing electric fields within prescribed safety limits. The fringing fields are reduced using near-field phased-array field-focusing techniques, wherein the adjacent modules of the multi-modular system are out-phased with respect to one another. The inter-module interactions in this multi-modular system can be modeled, and an approach to eliminate these interactions in a practical EV charging environment is provided. To illustrate one example implementation, a prototype 1.2-kW 6.78-MHz 12-cm air-gap multi-modular capacitive WPT system comprising two 600-W modules is provided. This prototype system achieves 21.2 kW/mpower transfer density and a peak efficiency of 89.8%. This multi-modular system also achieves a fringing field reduction of 50% compared to its individual modules.

Multi-modular capacitive wireless power transfer circuit and related techniques

The present disclosure provides a high-power-density power converter topology with a common neutral between its input and output AC ports while having a single DC bus. The topology may also be embodied as an online uninterruptible power supply (UPS). The presently-disclosed topology enables high power density by utilizing half-bridge switch structures suitable for MHz-frequency operation.

High power density power converter and uninterruptible power supply circuit and methods

Capacitive wireless power transfer systems are provided. In one embodiment, for example, the system comprises two pair of coupled conducting plates; a first matching network coupled to the first pair of conducting plates; and a second matching network coupled to the second pair of conducting plates. At least one of the first and second matching networks comprises an inductor having inductance value selected based on at least one parasitic capacitance value of the capacitive wireless power transfer system. In another embodiment, a method of designing a capacitive wireless power transfer system is provided comprising determining a parasitic capacitance value of a capacitive wireless power transfer system and determining an inductance value of an inductor of at least one of the first and second matching network having a value selected based on at least one parasitic capacitance value of the capacitive wireless power transfer system.

Capacitive wireless power transfer circuit and related techniques

Described herein are power conversion systems and related techniques which utilize a coupled split path (CSP) circuit architecture. The CSP structure combines switches, capacitors and magnetic elements in such a way that power is processed in multiple coupled split paths in a variety of voltage domains. These techniques are well suited for power conversion applications that have one or more input/output ports that have a wide voltage range, or if the application is interfacing with the ac line voltage and requires power-factor correction.

Coupled split path power conversion architecture

A systematic procedure for the synthesis of hybrid feedforward control architectures for pulse-width modulated (PWM) switching converters is provided. In this hybrid feedforward control architecture selected converter variables are sensed and utilized in a particular way based on the converter open-loop characteristics to determine the duty-cycle needed to achieve a control objective. Compared to standard feedback control techniques, advantages can include simpler controller implementation, more convenient sensing, and improved static and dynamic regulation. An example systematic procedure for developing hybrid feedforward controllers is illustrated by first considering a previously known example of hybrid feedforward control: hybrid feedforward control of a boost power factor correction (PFC) rectifier operating in discontinuous conduction mode (DCM). The hybrid feedforward control synthesis principles are also used to realize new hybrid feedforward control architectures, such as a four switch buck boost converter.

Hybrid feedforward control architecture and related techniques

One aspect of the invention provides a DC-to-DC driver including: a converter including an output configured to drive a load with an output current; and a feedback controller coupled to the converter. The feedback controller includes: a pulse-width modulator configured to output a first pulse-width modulated signal to the converter; a first switching mechanism coupled to the pulse-width modulator; a compensator having an output coupled to the first switching mechanism, the compensator configured to generate a first duty cycle control signal based on a comparison of the output current and a first reference voltage; and a sampler having an input coupled to the output of the compensator and an output coupled to the switching mechanism, the sampler configured to generate a second duty cycle control signal based on the first duty cycle control signal.

DC-to-DC drivers with high resolution dimming

In one implementation, an analytical approach to determining an improved and/or optimal design of a matching network in a capacitive or inductive WPT system is provided. In one implementation, for example, a framework is provided to enable stage(s) of the network to simultaneously provide gain and compensation. The multistage matching network efficiency can be improved and/or optimized, such as by using the method of Lagrange multipliers, resulting in the optimum distribution of gain and compensation among the L-section stages.

Growing community of inventors

Lexington, MA, United States of America

Khurram K Afridi