Soft switching and interleaving for sinusoidal input current AC to DC step down converters

A modified PWM scheme reduces switching losses (compared to centre aligned PWM) by a theoretical 32% in a three phase AC-DC step down converter with sinusoidal input currents. This scheme does not rely on the addition of any extra components, but rather solely on the adjustment of the PWM scheme. It is also shown that two paralleled converters' PWM patterns can be interleaved so as to reduce supply conducted switching harmonics. The effect of supply flat topping is also considered and the low frequency harmonic distortion produced is eliminated.