The problem with the approaches in [8]–[11] is that they
require continuous rectifier output current to function. In addition,
the rectifier output voltage needs to be ripple free to have
expected results, requiring a large filter capacitor. Moreover,
the current through the 360-Hz transformer (for 60-Hz grid)
has an amplitude of ±2IL resulting in a large conduction loss.
The noise generated by the low-frequency transformer poses
another problem.