Harmonic Mitigation in Induction-Motor Drives using Active Filtering Approach

This paper proposes a harmonic mitigation method in open ended induction-motor drive based on active filtering approach. Open ended motor has open stationary windings with two separate inverters feeding from either sides. With half input dc voltage this conventional configuration works as a three-level inverter. In this work, the stator winding is fed from one end by a SVPWM controlled primary voltage source inverter and other end by a secondary voltage source inverter. The secondary voltage source inverter is controlled to produce a voltage which will cancels out the harmonics in the motor phases. It is controlled using a series active filter algorithm to eliminate phase voltage harmonics, thereby reducing the motor losses and improves the efficiency and life span of the motor. The total harmonic distortion of the proposed drive scheme is less compared to conventional three-level open ended motor with additional advantage of no extra switching devices required. The proposed method is validated by simulation results.