Single-stage, unity power factor switching converter with voltage bidirectional switch and fast output regulation

A single-stage ac-to-dc switching converter for converting ac power from a utility line source to regulated output dc voltage for powering a load comprising

• a single-stage dc-to-dc switching converter operated at a constant frequency connected to said load and a capacitor in parallel, said single-stage dc-to-dc switching converter having an energy storage capacitor for suppressing low frequency current at twice the frequency of said ac power, and means for regulating said output voltage to said load by modulating a duty ratio of a switching means operated at said constant frequency, thereby providing output voltage regulation independent of input voltage to said single-stage dc-to-dc converter,
• a bridge rectifier with lowpass filtering means connected to said utility line,
• a voltage bidirectional switch connected between the output of said lowpass filtering means and said single-stage dc-to-dc converter,
• first means for sensing voltage across said energy storage capacitor in said single-stage dc-to-dc converter stage,
• means for comparing said voltage sensed by said first means with a reference voltage to produce an error signal, and
• means responsive to said error signal for regulating said voltage across said energy storage capacitor into said single-stage dc-to-dc converter by modulating a duty ratio of said voltage bidirectional switch operated at said constant frequency.