Patent ID: 6617814
Filing Date: 2003-09-09
Classification: H01F,H02M

Abstract:
A choke for providing a differential inductance and suppressing common-mode voltages in a motor drive having an AC to DC converter stage for converting AC power to DC power on a DC bus with positive and negative DC current paths, and an inventor stage for converting DC power from the DC bus to AC motor power in a controlled fashion, the choke comprising:a magnetic core having an inner leg extending between an upper member and a lower member, and first and second outer legs extending from the lower member toward the upper member and providing a first air gap between the first outer leg and the upper member and a second air gap between the second outer leg and the upper member; first and second differential coils wound around the first and second outer legs, respectively; and first and second common-mode coils wound around the inner leg; wherein the first and second differential coils are adapted for connection in the positive and negative DC current paths, respectively, to smooth the DC power on the DC bus, and wherein the first and second common-mode coils arc adapted for connection in the positive and negative DC current paths, respectively, to suppress common-mode voltages in the motor drive.