Vector control PWM-VSI induction motor drive with a long motor feeder: performance analysis of line filter networks

Long motor feeders are common for variable speed drives used in underground mines and sub-sea pumps. Over-voltage motor problems arise, and so filter networks are mandatory with voltage source inverters. Among the various filter types, the motor terminal resistor-capacitor (RC) filter and inverter output resistor-inductor-capacitor (RLC) filter are the most common. This article studies and compares the effects of such filters on the vector control performance and the motor voltage/current quality. The drive performance study considers no-load/load conditions in terms of line voltage and current harmonics, effects on flux and torque current components, DC-link current harmonics and common mode voltage. The effects of feeder length on filter losses, DC-link current and voltage regulation are also investigated. The effects of feeder parameters detuning errors on filter performance are analysed in detail. Simulation and practical results substantiate the study.