An Efficient Current Distortion Suppression Method for Six-Pulse Bridge Rectifiers

In this paper, an efficient current distortion suppression method for six-pulse bridge rectifiers is presented, whereby high-quality waveforms at both ends of the rectifier are possible. The methodology involves accurate shaping of the dc current by using two forced commutated switches. It is demonstrated, theoretically and experimentally, that this action on the dc side is reflected back on the ac side, and as a result, perfect sinusoidal input currents are achieved. In addition, ripple-free voltages and currents are obtained on the dc side by using electrolytic capacitors and smoothing reactors. Rectifying and inverting operations are possible with a simple control circuit, which is also able to both track rapid load variations and overcome failures more efficiently than other modern alternatives. Selected theoretical results are presented, which are fully validated in a laboratory prototype.