Abstract:
A controller is provided which can interface with a variable frequency drive and a motor, the controller having (a) one or more voltage and current sensors which can interface with a power line linking the variable frequency drive and the motor; and (b) a signal interface module which can receive electrical signals associated with an operating condition of the motor from the one or more voltage and current sensors. The signal interface module can correlate the received electrical signals with a rotor position of the motor, and transmit signals corresponding to rotor position, to the variable frequency drive. The data provided by the controller if conveyed as a rotor position, may cause the variable frequency drive to change one or more of its operating parameters to maintain proper synchronization of the rotor and its associated stator currents. Alternatively, the controller may directly control variable frequency drive operating parameters.
Abstract:
A power control sub-system for controlling a plurality of electric machines disposed in a well is disclosed. The power control sub-system includes at least one power cable configured to conduct a direct current to and/or from one or more electric machines of the plurality of electric machines. The power control sub-system further includes a switching device disposed proximate to one or more of the plurality of electric machines in the well, where the switching device is electrically coupled to the at least one power cable and the plurality of electric machines, and where the switching device is capable of withstanding high temperatures and is configured to selectively control supply of the direct current to and/or from one or more electric machines of the plurality of electric machines. A fluid extraction system employing the power control sub-system and a method of controlling the plurality of electric machines are also disclosed.