Linear permanent magnet motor driven downhole plunger pumping unit

An oil-well pumping unit, comprising:

• a ground-based control unit comprising a channel for measuring a back-EMF generated by the oil well pumping unit,
• a downhole part connected to said ground-based control unit, said downhole part comprising:
• a plunger pump, said plunger pump comprising:
• discharge valves,
• a filter,
• a gravity gas separator,
• one or more non-return valves mounted above said gravity gas separator, and
• a coupling located above said one or more non-return valves, said coupling being adapted to connect a flow tubing,
• a slider upstroke damper, and
• a slider downstroke damper,
• a downhole linear motor connected to said plunger pump, said downhole linear motor comprising:
• a housing,
• a stator fixed relative to said housing, said stator comprising a three-phase winding and temperature sensors,
• said stator further comprising:
• an internal stator bore, said internal stator bore housing a reciprocating slider,
• a stator cavity filled with a dielectric fluid,
• a slider cavity filled with a lubricant,
• the reciprocating slider being rigidly connected to a moving part of the plunger pump via an extension bar, and
• a communicatively coupled downhole telemetry unit comprising at least one fluid temperature sensor, a pressure sensor, a vibration sensor, and an inclinometer,
• wherein said ground-based control unit further comprises an inverting rectifier, wherein said ground-based control unit is connected to said downhole linear motor via a neutral wire, said ground-based control unit being configured to receive said back-EMF generated in said three-phase winding, said ground-based control unit determining a position of the slider based on said back-EMF, said ground-based control unit signalling for and causing a reverse motion of the slider when the slider reaches a top or a bottom of said downhole linear motor.