Patent ID: 8154895

Claim:
An apparatus for converting three phase AC voltages on first, second and third input lines to DC voltage across positive and negative DC buses, the apparatus comprising: a rectifier including first, second and third rectifier legs, each leg including a switch and a diode wherein the switch is linked between the positive DC bus and a cathode of the diode, an anode of the diode is linked to the negative DC rail and the first, second and third diode cathodes are linked to the first, second and third input lines, respectively; a DC bus voltage sensor linked to the positive DC bus and measuring the DC bus voltage to generate a measured DC bus voltage; a rectifier controller that receives the measured DC bus voltage, a reference voltage value and the three phase AC voltages wherein, when the measured DC bus voltage is at least equal to the reference voltage value, the controller turns on the switches in the first, second and third rectifier legs when the voltages on the first, second and third input lines are positive, respectively, the controller maintaining the switches off in the first, second and third rectifier legs when the measured DC bus voltage is less than the reference voltage value; and a pre-charge circuit linking at least one of the input lines to the positive DC bus.