General Electric Company

Ge Energy Power Conversion Technology Gmbh

Xiaohong Li

John Erik Hershey

Zhiyuan Ren

John Anderson Fergus Ross

Xuefeng Wang

Jovan Z Bebic

Xeufeng Wang

Nathaniel B Hawes

Provided is a modular multilevel converter and a method for synchronizing outputs of sub-modules of the converter. The modular multilevel converter includes sub-modules connected in parallel, and each sub-module generates an output. The modular multilevel converter also includes a controller that is communicatively coupled to the sub-modules. The controller controls a flow of one or more synchronizing signals between the plurality of sub-modules, such that each sub-module receives the synchronizing signals in opposite directions simultaneously, thereby controlling a synchronization of the outputs generated by the sub-modules.

Switching synchronization for modular multilevel converters

A method for processing information is provided. The method includes directing a laser beam to a first track of a first layer of a holographic storage medium. The method also includes recording a base voltage based on a look-up table. The method includes directing the laser beam to a target track in the first layer, based on position information in tracks. Further, the method includes recording an offset voltage for the target track into the look-up table. Still further, the method includes directing the laser beam to a target layer based on position information in vertical wobbles. The method also includes recording an offset voltage for the target layer into the look-up table. Finally, the method includes determining a final voltage based on the look-up table and applying the final voltage to an actuator for moving the laser beam to a final target position in the holographic storage medium for recording and retrieval of information.

Method and system for processing information from optical disk layers

Techniques are provided for using a multi-stage actuator to actuate one or more optical components of an optical head. The multi-stage actuator includes a cross-layer displacement component which actuates an optical component to change the beam focus in a displacement range corresponding to the thickness of the data layers in a holographic disk, such that a beam is impinged on the target data layer. The multi-stage actuator also includes a intra-layer focusing component which actuates the optical component in a smaller range to focus the beam on the target data position. The cross-layer displacement component and the intra-layer focusing component may each include more than one actuator. In some embodiments, the focusing component also actuates the optical component in a tilting motion to compensate for movement or imperfections of the disk during a reading or recording process.

Multi-stage focus actuator and optical head

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Clifton Park, NY, United States of America

Xiaohong Li