An Improved Power-Quality 30-Pulse AC–DC for Varying Loads

The proposed 30-pulse ac-dc converter is based on
a polygon-connected autotransformer with reduced magnetics.
The proposed ac–dc converter is able to eliminate lower than
29th order harmonics in the ac supply current. The resulting
supply current is near sinusoidal in shape with low total harmonic
distortion and a nearly unity power factor. Moreover, the design of
an autotransformer is modified to make it suitable for retrofit applications,
where presently a 6-pulse diode bridge rectifier is used