Modeling for Speed Control of Induction Motor in Subsea Applications

Oil/Gas offshore extraction involves long feeders being used to supply power to Induction motors. Modeling previously was done ignoring effects of long feeders and line parameters. We design a model considering Long feeder effects and use of inverter output filters. We considered Field oriented control technique. Due to subsea applications we implement control technique at stator side itself. Stator values are measured and then transformed from three phase to 2 phase values using Clarke transform blocks. Long feeder is modelled as a π-model equivalent considering lump parameters.LC filter is used at inverter output to improve output response. Transformed values are fed to the designed controller which again feeds signal to inverter via SVPWM. Simulation and experiments show that model can be effectively controlled from stator side, LC filter helps to obtain a near sinusoidal output response and also helps to reduce harmonics and dv/dt rising of output voltage.