The reason SCRs are not used is due to increased copper losses as the conduction angle decreases. If Scrs are used to reduce the voltage by 50% and 66%, but the average rectified current into the battery remains the same, then I^2R losses in the coil are going double, triple, respectivly.
Buck regulators maintain a full 120 degrees of conduction in a 3 phase rectifier. In addition to this, if a buck regulator is used on a single phase unfiltered rectifier, than the conduction angle can be increased further, up to say about 150/160 degrees, at a dc output of 1/4 of the ac peak voltage. (on a sinewave machine) PMA's oftem produce trapezoidal waveforms, and that won't be a significant difference. [ Parent ]
