General Electric Company

Julien Bouhraoua

Jean-Francois Larroux

Aurelien Gadenne

Uwe Wiedmann

Mark Alan Frontera

Philippe Ernest

Nicolas Levilly

Jean-François Larroux

Janusz Rodziewicz

Aurélien Gadenne

In the present invention, a high-voltage DC/DC converter suitable for powering x-ray tubes and the like provides control of a voltage applied to a resonant circuit at least in part according to a timing of a monitored voltage on the resonator thereby compensating for variations in the parameter stability of the resonant circuit, nonlinearity in the resonant gain curve and frequency dependencies.

High-performance DC/DC converter with resonator sensing

Rise times and fall times provided by a high voltage generator are controlled to maintain image quality during such scans. The rise and fall times are controlled by first measuring rise and fall times at each transition. Then, a closed-loop controller is used to adjust control parameters of the high voltage generator, based on an error determined from the measurement, to achieve substantially constant rise and fall times. This invention may be based on the implementation of two closed-loop controllers on rise and fall time of fast-kV exposures. As a result, image quality may be improved and system calibration time may be reduced.

Energy imaging with controlled rise and fall times

The present inventors have recognized that fall times between high-kV to low-kV levels (during a 'dual energy' or 'fast-kV' energy scan) are linked to the discharge of HV (high voltage) capacitance. In an embodiment of the invention, a high voltage generator may be activated during fall transitions from first to second energy levels in order to substantially maintain a predetermined fall transition time. Accordingly, substantially equal energy distributions between high-kV and low-kV levels may be achieved.

Energy imaging with generally constant energy separation

A system for controlling a multilevel soft switching power converter including a DC bus, a pair of switching arms, and a controller is disclosed. The DC bus has a positive rail and a negative rail operable to have a voltage potential present across the DC bus. Each switching arm is connected between the positive rail and the negative rail and includes four soft switches. Each soft switch is connected between the positive rail, the negative rail, or one of three intermediate connections between the positive and negative rails. Each soft switch is also controlled by a gating signal. A flying capacitor is connected between the first intermediate connection and the third intermediate connection and an output terminal is connected at the second intermediate connection of each switching arm. A controller is operable to generate each of the gating signals utilizing at least three control routines.

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Buc, France

Julien Bouhraoua