sixpulse

Sixpulse refers to a six-pulse rectifier arrangement commonly used in power electronics. It typically consists of six diodes connected in a three-phase bridge fed by a three-phase AC source, producing a DC output. In operation, two diodes conduct at any given 60-degree interval, resulting in a pulsating DC waveform with six distinct pulses per AC cycle. The DC ripple frequency is six times the AC line frequency (for 50 Hz, 300 Hz; for 60 Hz, 360 Hz).

Uncontrolled six-pulse rectifiers rely on diodes and provide no adjustable output voltage, while controlled variants replace diodes with thyristors or other controlled switches, enabling regulation of DC voltage and current through firing angle control. In both cases, the six-pulse topology is valued for simplicity, ruggedness, and high power handling, but introduces substantial low-order harmonics into the supply, requiring reactive power support and harmonic mitigation.

Common applications include industrial DC drives for motors, electric traction, electrolysis, and HVDC back-to-back stations. The topology is often paired with transformers and filters; to reduce harmonics, designers use phase shifting to create 12-pulse or higher-pulse rectifier configurations or add dedicated LC/AC filters. The six-pulse approach is a building block for more complex rectifier systems, such as twelve-pulse configurations obtained by transformer phase-shifting two six-pulse bridges.