Active Magnetic Bearing for Tubular Linear Induction Motor Applied to Onshore Oil Exploitation

A tubular linear induction motor applied to onshore oil exploitation was proposed recently. Its purpose is to directly drive the sucker-rod pump installed in the down hole of the oil well. In continuing the research an active magnetic bearing (AMB) was developed and applied to the motor in substitution to the existing mechanical bearing. Instead of the usual eight-pole AMB, a different concept is adopted where a DC-excited primitive bearingless machine is used as a magnetic bearing. The magnetic bearing levitation control is executed by a digital controller using an AD/DA converter and a control algorithm implemented in FPGA hardware. A linear model is written to describe its dynamics. In this work the AMB system is studied with particular emphasis to the experimental results obtained with the prototype in operation. Tests performed on this prototype show that the AMB can be an interesting alternative to be considered in this context.