Low distortion 3-phase rectifiers utilizing harmonic correction circuit topologies with both IGBT and thyristor switches

The operation of a family of harmonic correction networks for 3 phase diode rectifiers is described that use a combination of thyristor and IGBT switches. Four distinct networks are described that provide a variety of current waveshaping techniques. Variations of these networks either lower the size of the line inductors required or use very low switching frequencies. The IGBT switches are used for thyristor commutation and an improved current waveshaping function. The thyristors are used to select the appropriate phase of the AC supply to inject current pulses. The resultant harmonic correction networks are low cost and have very low per unit current ratings. The resultant complete rectifier topology can be operated with a very low harmonic distortion in the AC supply current. Design parameters are given in per unit to illustrate the very low device per unit current ratings.