Coldwatt, Inc.

Rensselaer Polytechnic Institute

Innovative Technology Licensing LLC

Flextronics International Usa, Inc.

Rockwell Scientific Company

Jian Sun

Vivek Mehrotra

Sriram Chandrasekaran

Kenneth F Webb

Xiukuan Jing

A method for forming and operating a multi-terminal power system, includes: connecting multiple sending terminals to a network of a power system; and local control of each sending terminal to behave as a constant-power source such that both output voltage and output current of the sending terminal may simultaneously vary in response to changing external circuit conditions while maintaining constant a product of the output voltage and the output current of the sending terminal. At least one sending terminal may include a capacitive output converter having a capacitor connected between two output terminals and a controlled current source connected in parallel to the capacitor, or an inductive output converter having an inductor connected to an output terminal and a controlled voltage source connected in series with the inductor.

Methods to form and operate multi-terminal power systems

A multi-terminal DC power system includes: a DC network connecting together multiple terminals. Each terminal is represented by one of: a voltage source converter having a capacitor at an interface to the DC network, wherein a difference between a converter-side current and a network-side current charges the capacitor, and a current source converter having an inductor at an interface to the DC network, wherein a difference between a converter-side voltage and a network-side voltage drives current through the inductor. A local controller for each terminal directly controls the converter-side current of each voltage source controller and the converter-side voltage of each current source converter, independent of the terminals, leaving network-side currents and voltages to be determined by the network, resulting in simplified terminal control and avoidance of the need for high-speed communication among all terminals at all times.

Multi-terminal DC power systems employing autonomous local control methods

A vertical winding structure for planar integrated magnetics used in switched-mode power converters maintains close coupling between the different windings but reduces the eddy current losses, lowers the DC winding resistance and reduces the number of layers of the PCB. Vertical and horizontal windings can be used together without sacrificing these performance advantages and further minimizing the capacitive coupling between the outer-leg windings and the center-leg winding. This winding structure can be used in a wide range of magnetic structures including isolated and non-isolated CDRs, interleaved CDRs, and buck and boost converters.

Vertical winding structures for planar magnetic switched-mode power converters

Cutout and/or keep away regions are etched in the winding structure near the gapped center leg of a magnetic core. This reduces eddy current losses caused by the leakage field and improves current uniformity and current sharing between windings thereby increasing converter efficiency. Windings closest to the air gap are suitably formed with both keep away regions and cutouts. Windings a little further away are formed with only cutouts, and the windings furthest away are unchanged. This approach keeps the net winding losses low in the presence of a fringing field. The precise configuration is determined by the core structure, air gap and winding arrangements.

Winding structure for efficient switch-mode power converters

There is disclosed a core structure with a very low profile, high power density and lower losses. The disclosed design allows for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can be effectively employed in vertically packaged power converters and modules. Also disclosed is a DC-DC converter topology which preferably employs the disclosed core. N AC drive voltages drive N current doubler rectifiers (CDRs) in accordance with the symmetric modulation scheme; each CDR provides two rectified output currents to an output node. Each AC drive voltage has a switching period T. The drive voltages are phase-shifted by T/(2*N), such that the rectified output currents of the CDRs are interleaved, thereby reducing output voltage ripple.

Core structure and interleaved DC&#x2014;DC converter topology

A vertically packaged cellular power converter solves the problems associated with conventional designs and paves the way for a cellular circuit architecture with ultra-low interconnect resistance and inductance. The vertical packaging results in a power flow in the vertical direction (from the bottom to the top) with very short internal interconnects, thereby minimizing the associated conduction losses and permitting high conversion efficiency at high currents. The cellular architecture is ideally suited for generating multiple supply voltages.

Vertically packaged switched-mode power converter

A composite magnetic core formed of a high permeability material and a lower permeability, high saturation flux density material prevents core saturation without an air gap and reduces eddy current losses and loss of inductance. The composite core is configured such that the low permeability, high saturation material is located where the flux accumulates from the high permeability sections. The presence of magnetic material having a relatively high permeability keeps the flux confined within the core thereby preventing fringing flux from spilling out into the winding arrangement. This composite core configuration balances the requirements of preventing core saturation and minimizing eddy current losses without increasing either the height or width of the core or the number of windings.

Composite magnetic core for switch-mode power converters

There is disclosed a core structure with a very low profile, high power density and lower losses. Higher core surface area and improved core utilization in terms of flux density are other desirable feature in the disclosed design. The disclosed design also allowed for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can also be effectively employed in vertically packaged power converters and modules.

Core structure

A converter circuit includes a magnetic core, a primary winding, a secondary winding, a main rectification circuit, and an auxiliary rectification circuit. The primary winding and the secondary winding are wound around the magnetic core. The main rectification circuit and the auxiliary rectification circuit are both connected to the secondary winding and produce output voltages having different magnitudes. The auxiliary voltage powers the control and drive circuits for both the primary switches and the synchronous rectifiers used for the main rectification circuit.

Switching power converter circuits providing main and auxiliary output voltages

A converter and rectifier circuit comprises a magnetic core, a first secondary winding, a second secondary winding, a third secondary winding, a first rectifier, a second rectifier and an output capacitor. The first, second and third secondary windings are wound around the magnetic core and are connected to each other. The first rectifier is connected to the first secondary winding and the second rectifier is connected to the second secondary winding. The output capacitor is connected to the first and second rectifiers and is connected in series with the third secondary winding.

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Jian Sun