Virginia Tech Intellectual Properties Inc

The Boeing Company

Hamilton Sundstrand Corporation

Bo Wen

Dushan Boroyevich

Rolando Burgos

Paolo Mattavelli

Kamiar J Karimi

Dong Dong

Rodrigo Fernandez-Mattos

Andrew F McLean

Jun Wang

Sheau-Wei Johnny Fu

Marko Jaksic

Bo Zhou

Jiewen Hu

Marko D Jaksic

A switching bridge for the DC-DC stage of a power converter, the switching bridge having one or more sets of upper and lower series-connected switches (S, S) connected across a DC bus and arranged to be switched to provide an output AC voltage, the switching bridge further comprising a voltage divider (C) arranged to vary the output AC voltage level according to the switching state of the switches.

Switching bridge for wide gain converter

In a modular multi-level power converter, additional switching states are interleaved between main switching states that control output voltage or waveform. The additional switching states provide current from a DC-link to charge capacitors in respective modules or cells to an offset voltage from which the capacitor voltages are controlled toward a reference voltage during each switching cycle rather than being allowed to build up over a period of an output waveform of variable line frequency, possibly including zero frequency. Since the switching cycle is much shorter than the duration of a line frequency cycle and the capacitor voltages are balanced during each switching cycle, output voltage ripple can be limited as desired with a capacitor of much smaller value and size than would otherwise be required.

Power-cell switching-cycle capacitor voltage control for modular multi-level converters

A method and apparatus for electrical power system stability optimization. An electrical power system comprising source elements and load elements is simulated to generate impedance data, wherein the impedance data identifies an impedance of the electrical power system. A stability profile of the electrical power system is characterized as a function of the impedance data, wherein the stability profile identifies the source elements and load elements to control power generation by the electrical power system to optimize stability of the electrical power system.

Electrical power system stability optimization system

A small signal feedback loop or feed-forward loop having gain provides substantially unconditional instability in a phase locked loop when a reference phase signal is lost. The small signal feedback or feed-forward also modifies phase locked loop bandwidth when the reference phase signal is lost to increase rapidity of response to loss of reference phase signal while maintaining insensitivity to reference voltage amplitude change while the reference phase signal is present. The performance thus achieved is particularly suitable for rapid condition detection response and control of a grid connected power converter under islanding conditions.

Anti-islanding protection in three-phase converters using grid synchronization small-signal stability

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Blacksburg, VA, United States of America

Bo Wen