Harmonic eliminating PWM converter

摘要

A PWM based converter including a Y- DELTA , Y-Y transformer (or a DELTA - DELTA , DELTA -Y transformer) wherein the Y- DELTA portion of the transformer phase shifts input voltage by 30 DEG with respect to the Y-Y portion of the transformer and thereby eliminates many low order supply line harmonics. The rectifier also includes two series connected PWM switching rectifiers, one rectifier receiving input voltages from the Y-Y portion of the transformer and the other rectifier receiving input voltages from the Y- DELTA portion of the transformer, and a controller for controlling the first and second rectifiers so as to eliminate low order harmonics on the supply lines that are not eliminated by the transformer. A capacitive bank is required between each rectifier and the transformer.