Experimental Design of Low Loss Filter to mitigate Overvoltage for Long Cable Fed Induction Motor Drive

Abstract

Overvoltage stress in long cable drive can dramatically reduce the reliability of insulation systems without suitable protection. This paper investigates the over-voltage mitigation and controlling techniques at motor terminal of Pulse Width Modulated (PWM) inverter fed induction motor for long cable lengths. A new approach to the high frequency model of power cable using T-network is depicted in the proposed work. Using proposed high frequency model of T network helps to predict over voltage compared to other cable model and give more accurate validation with experimental results. Detailed design equations for different types of passive filters such as RC, RLC and LC filters are presented. Simulation results indicate that LC filter contributes better performance compared to other filters. Simulation and experimental results are compared to verify the design of the proposed LC filter for three phase 1 HP induction motor connected to commercial AC motor drive through different lengths of three-core cable.