Power converter system topologies comprise a first DC/DC converter to pull a positive rail of a high voltage bus up, while a second DC/DC converter pushes a negative rail of the high voltage bus down. One or both the DC/DC converters may be bi-directional. Such topologies are suitable for use with separate primary power sources, and/or auxiliary power sources. Such topologies may include a DC/AC converter, which may be bi-directional. Such topologies may include one or more auxiliary DC/DC converters, which may be bi-directional. Multiple substrates, including at least one stacked above another may enhance packaging.