A power distribution system includes at least two DC buses and at least two AC buses and a plurality of converter units interconnecting the DC buses and the AC buses in a ring. The system may further include one or more AC power sources (e.g., utility feeds, engine-generator sets, etc.) connected to selected ones of the AC buses and/or one or more DC power sources (batteries, capacitor banks, fuel cells, etc.) connected to selected ones of the DC buses. The ring configuration can support a variety of AC and DC loads and provide redundancy and power distribution among the power sources.