A transformer tap-changing circuit comprises an apparatus that includes a transformer comprising a secondary winding configured to inductively couple to a primary winding when a current is passed through the primary winding from an energy source, a first rectifier coupled to the secondary winding and configured to rectify a first AC voltage from the secondary winding into a first DC voltage, and a second rectifier coupled to the secondary winding and configured to rectify a second AC voltage from the secondary winding into a second DC voltage. The apparatus also includes a DC bus coupled to the first and second rectifiers and configured to receive the first and second DC voltages therefrom, wherein the first AC voltage is higher than the second AC voltage, and wherein the first DC voltage is higher than the second DC voltage.