What is claimed is:1. An adaptable power stage (A-PS) for an adaptable power converter, the A-PS comprising:four high-current solid state power switches (HCPS), arranged and electrically coupled to form a reconfigurable H-bridge converter (RH-BC) comprising a plurality of current routing junctions (CRJ); anda plurality of respective current flow control (CFC) modules coupled to respective current routing junction modules, each current routing junction module comprising one or more current flow contactors (CFC);wherein the adaptable power stage is adaptable for a plurality of alternative power conversion modes, each power conversion mode of the plurality of alternative power conversion modes is determined at least in part via a specific set of open/closed settings of the one or more power contactors of the CFC modules.2. The A-PS of claim 1, wherein at least one CFC module of the plurality further comprises:an inductor; andone or more current flow contactors which may be switchably set to enable current flow through the inductor or to prevent current flow through the inductor.3. The A-PS of claim 1, wherein at least one CFC module of the plurality further comprises a plurality of current flow contactors, wherein the plurality of current flow contactors are coupled to provide for at least one of:(i) two or more different current paths between a first current resource 302.n and the RH-BC);(ii) two or more different current paths between a second current resource 302.n and the RH-BC); and(iii) two or more different current paths between a first CFC module and a second CFC module;(iv) a selection of either a current flow or a non-current flow through a selected high-current power switch of the RH-BC;(v) a selection between no current flow and current flow from a drain (D) or a source (S) of a selected high-current power switch of the RH-BC; and(vi) a selection between a first current path and second current flow path for a drain (D) or a source (S) of a selected high-current power switch of the RH-BC.4. The A-PS of claim 1, further comprising a microcontroller unit (MCU) (327) configured to control the open/closed states for one or more current flow switches.5. The A-PS of claim 1, wherein the plurality of current flow control (CFC) modules comprises a CRC module configured to switchably determine if a current flow between a first power resource port (An, Bn) and the RH-BC module includes or does not include an inductor L1, wherein:the inclusion of the inductor L1 configures the A-PS for current source conversion at the first power resource port; andthe exclusion of the inductor L1 configures the A-PS for voltage source conversion at the first power resource post.6. The A-PS of claim 1, wherein the plurality of current flow control (CFC) modules comprises a CRC module with a plurality of contactors SW3, SW4, SW5, SW6, SW7, SW16, SW8, SW9 which are configured to select, in combination, from among a plurality of current flow paths between the RH-CB module and a second power resource port (Xn, Yn) of the A-PS.7. The A-PS of claim 1, wherein the plurality of alternative power conversion modes comprises: a DC?DC buck mode (CM1); a DC?DC boost mode (CM2); a DC?DC buck and boost mode (CM3); a DC?AC mode (CM4); and an AC?AC mode (CM5).8. The A-PS of claim 7, wherein the plurality of alternative power conversion modes further comprises a DC?AC/DC mode (CM6).9. The A-PS of claim 8, wherein:the A-PS comprises twelve current flow contactors, andthe plurality of alternative conversion modes are switchably selectable via open/closed settings for the twelve current flow contactors.10. The A-PS of claim 9, wherein the twelve current flow contactors, the two inductors, and the four high current power switches are electrically coupled according to the schematic configuration of FIG. 3A.11. The A-PS of claim 10, wherein the plurality of conversion modes are selectable at least in part via specific open/closed settings of the current flow contactors according to the Table A of FIG. 3C.12. The A-PS of claim 1, wherein the current flow contactors are configured to provide for at least one conversion mode with a reversible flow for either of a DC-to-AC current and an AC-to-DC current between a first power-resource port 302.1 and a second power-resource port 302.2 of the A-PS, wherein a single set of current flow contactor settings provides for the either of a DC-to-AC current and an AC-to-DC current.13. An adaptable power electronics building block line replacement unit (A-PEBB LRU) comprising:a first adaptable power stage and a second adaptable power stage; anda solid state transformer;wherein:the first adaptable power stage and the second adaptable power stage are coupled in series via the solid state transformer;the first adaptable power stage and the second adaptable power stage each provide for a respective first and second power resource port of the A-PEBB LRU; andthe A-PEBB LRU is adaptable, via settings of the first and second adaptable power stages, for a plurality of power conversion modes.14. The A-PEBB LRU of claim 13, wherein the solid state transformer comprises a first isolation bridge-converter and a second isolation bridge-converter (210.2) which are coupled in series via a high frequency transformer.15. The A-PEBB LRU of claim 13, wherein each adaptable power stage of the first adaptable power stage and the second adaptable power stage comprises:four high-current solid state power switches (HCPS), arranged and electrically coupled to form a reconfigurable H-bridge converter (RH-BC) comprising a plurality of current routing junctions (CRJ); anda plurality of respective current flow control (CFC) modules coupled to respective current routing junction modules, each current routing junction module comprising one or more current flow contactors (CFC);wherein the adaptable power stage is adaptable for a plurality of alternative power conversion modes, each power conversion mode of the plurality is determined at least in part via a specific set of open/closed settings of the one or more power contactors of the CFC modules.16. The A-PEBB LRU of claim 15, wherein at least one CFC module of each adaptable power stage further comprises:an inductor; andone or more current flow contactors which may be switchably set to enable current flow through the inductor or to prevent current flow through the inductor.17. The A-PEBB LRU of claim 15, wherein at least one CFC module of each adaptable power stage further comprises a plurality of current flow contactors, wherein the plurality of current flow contactors are coupled to provide for at least one of:(i) two or more different current paths between a first current resource and the RH-BC);(ii) two or more different current paths between a second current resource and the RH-BC); and(iii) two or more different current paths between a first CFC module and a second CFC module;(iv) a selection of either a current flow or a non-current flow through a selected high-current power switch of the RH-BC;(v) a selection between no current flow and current from a drain (D) or a source (S) of a selected high-current power switch of the RH-BC; and(vi) a selection between a first current path and second current flow path for a drain (D) or a source (S) of a selected high-current power switch of the RH-BC.18. The A-PEBB LRU of claim 15, further comprising a microcontroller unit (MCU) configured to control the adaptable power stages.19. The A-PEBB LRU of claim 13, wherein the plurality of power conversion modes comprises: a DC?DC buck mode (CM1); a DC?DC boost mode (CM2); a DC?DC buck and boost mode (CM3); a DC?AC mode (CM4); and an AC?AC mode (CM5).20. The A-PEBB LRU of claim 19, wherein the plurality of power conversion modes further comprises a DC?AC/DC mode (CM6).21. An adaptable power electronics building block power (A-PEBB) power converter comprising at least one adaptable power electronics building block line replacement unit (A-PEBB LRU) according to claim 13, wherein:the A-PEBB LRU is adaptable for a plurality of alternative power conversion modes, each respective power conversion mode of the plurality of alternative power conversion modes being determined at least in part via a specific, respective set of open/closed settings of one or more switchable power contactors of the A-PEBB LRU; andthe A-PEBB power converter is adaptable for the plurality of alternative power conversion modes via the power conversion mode settings of the at least one A-PEBB LRU.