Low distortion rectifiers for induction motor drives using harmonic correction networks with low per-unit current ratings

A family of harmonic correction networks is described for the input rectifier of 3-phase induction motor drives. These networks lower the supply current harmonic distortion by using thyristors to selectively inject current pulses into the AC supply. IGBT switches are used to commutate the thyristors and to further improve the supply current waveshape. Three separate harmonic correction networks are examined that have low electrical stresses with low per unit current ratings, and that lower the size of the supply inductors required