Integrated high-quality rectifier-regulators

A new family of ac-dc converters is derived which integrate the functions o f low-harmonic rectification, low-frequency energy storage, and wide-bandwi dth output voltage control into a single converter containing one, two, or four active switches, These converters utilize a discontinuous conduction m ode input inductor, an internal energy storage capacitor, and transformer s econdary circuits which resemble the bridge, forward, flyback, or Cuk dc-dc converters. A large-signal equivalent circuit model for this family is pre sented, which uses the "loss-free resistor" concept. Design strategies and experimental results are given. High-performance regulation with satisfacto ry line-current harmonics is demonstrated with conventional duty-ratio cont rol. Further improvements in line current are possible by simultaneous duty -ratio and switching-frequency control.