SYSTEMS AND METHODS FOR REDUCING PUMP DOWNTIME BY DETERMINING ROTATION SPEED USING A VARIABLE SPEED DRIVE

摘要

Systems and methods for using variable speed drives to restart downhole submersible pump motors. In one embodiment, a downhole pump is controlled using a variable speed drive that includes a control system configured to detect interruptions in the operation of the pump system. After an interruption that requires the restart of the pump motor, the control system determines the reverse rotational speed of the pump motor and restarts the motor when this speed is sufficiently low. The control system may be configured to reduce the output voltage of the variable speed drive and sweep through a range of output frequencies to determine the frequency at which the current drawn by the motor is lowest. This is the frequency at which the drive's output matches the speed of the motor and the apparent impedance of the motor is highest. When the speed is low enough, the motor is restarted.