Canrig Drilling Technology Ltd.

Nabors Drilling Technologies Usa, Inc.

Letourneau Technologies Drilling Systems, Inc.

Pace, Gary

Robbins, Larry Charles

Gary Pace

Kevin R Williams

James Garaghty

Brian Ellis

Beat Kuttel

Tommy Scarborough

Larry Charles Robbins, Jr

A power system for an electrical system with highly fluctuating loads is powered by one or more power sources that are slow to react to load changes. The power sources are connected to electrical equipment used on the drill rig which provide active load to the generate. One or more load banks may be positioned to provide passive load to the generators to maintain generally constant generator load, while allowing for instant access to power as active load increases. Generators may be run at 100% capacity, a maximum efficient capacity, or at a high enough level to allow for a sufficiently rapid increase in power output. At least one parameter of a drilling operation may be utilized to anticipate load demand changes.

Generator load control

A low inertia permanent magnet motor includes a stator and rotor. The rotor includes a generally tubular and hollow rotor body coupled to the shaft of the motor by one or more spokes and/or webs. The permanent magnets of the rotor are coupled to the rotor body. In some embodiments, the low inertia permanent magnet motor may be used to power a drawworks. In some embodiments, the drawworks may be controlled by an active heave compensation controller.

Low inertia direct drive drawworks

A method for limiting the torque of a permanent magnet AC motor includes a torque limit controller. The torque limit controller at least in part bases the torque limit on a selected direct voltage limit. The selected direct voltage limit may be used in combination with other torque limit conditions to generate the torque demand for the AC motor.

Method for controlling torque in permanent magnet motor drives

A power system for an electrical system with highly fluctuating loads is powered by one or more power sources that are slow to react to load changes. The power sources are connected to electrical equipment used on the drill rig which provide active load to the generators. One or more load banks may be positioned to provide passive load to the generators to maintain generally constant generator load, while allowing for instant access to power as active load increases. Generators may be run at 100% capacity, a maximum efficient capacity, or at a high enough level to allow for a sufficiently rapid increase in power output. At least one parameter of a drilling operation may be utilized to anticipate load demand changes.

A method for field weakening control of a three phase permanent magnet AC motor in a VFD drive. The VFD drive calculates the three phase voltages to be supplied to the AC motor via a three phase inverter using feedback and feed-forward calculations of quadrature and direct demand currents.

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Cypress, TX, United States of America

Gary Pace