An Uninterruptible Power Supply (UPS) including an input configured to receive input AC power having an input AC voltage, a backup power input configured to be coupled to a backup power source and to provide DC power to the backup power source for charging, a positive DC bus and a negative DC bus, the positive and negative DC busses being galvanically coupled to the backup power input, and a converter coupled to the input, the backup power input, and the positive and negative DC busses, the converter including a first inductor, a second inductor, a first converter switch configured to couple the first inductor to a neutral connection, a second converter switch configured to couple the second inductor to the positive DC bus, and a third converter switch configured to couple the second inductor to the negative DC bus, wherein the UPS is voltage-frequency independent.