Patent ID: 7633782

Claim:
A power factor corrected 3-phase ac-dc converter comprising phase A, phase B and phase C ac inputs for connecting respectively, individually, to three phases of a 3-phase ac power source, an output for connecting to and supplying a dc output voltage to a load, at least a first phase A switch, at least a first phase B switch and at least a first phase C switch having respective at least a first phase A switch input, at least a first phase B switch input and at least a first phase C switch input connected individually, respectively to the phase A, phase B and phase C ac inputs for controlling the flow of current from the respective phase A, phase B and phase C ac inputs the at least a first phase A switch, at least a first phase B switch and at least a first phase C switch having respective at least a first phase A switch output, at least a first phase B switch output and at least a first phase C switch output connected collectively to the input of an inductor, to comprise a 3-phase ac-dc buck converter, the at least a first phase A switch, at least a first phase B switch and at least a first phase C switch having respective duty-cycles Da, Db and Dc defined respectively, generally, for normal operation, in accordance with the equations Da = Sin ⁢ ⁢ X max ⁢ {  Sin ⁢ ⁢ X  ,  Sin ⁡ ( X + 120 )  ,  Sin ⁡ ( X + 240 )  } ⁢ Db = Sin ⁢ ⁢ ( X + 120 ) max ⁢ {  Sin ⁢ ⁢ X  ,  Sin ⁡ ( X + 120 )  ,  Sin ⁡ ( X + 240 )  } ⁢ Dc = Sin ⁢ ⁢ ( X + 240 ) max ⁢ {  Sin ⁢ ⁢ X  ,  Sin ⁡ ( X + 120 )  ,  Sin ⁡ ( X + 240 )  } ⁢ where “X” is a phase angle of the 3-phase ac power source, the ac-dc buck converter being connected to a power modulator having a transfer ration n and means for controlling the transfer ratio n so as to adjust the transfer ratio n to regulate the dc output voltage.