Power system using a multi-functional power interface unit

In a power system including an internal combustion engine coupled to drive a main alternator and an auxiliary alternator, the main alternator coupled to power through a main power bus one or more traction motors and the auxiliary alternator coupled to power through an auxiliary power bus predetermined electrical equipment, a power interface unit electrically coupled to the main power bus to capture and transfer electrical energy into the auxiliary power bus, at least some of the electrical energy being generated during a predetermined mode of operation of the system, the power interface unit comprising;

• a voltage converter module selectively coupled to impart a desired voltage conversion to voltage signals propagating between the main power bus and the auxiliary power bus to transfer the captured electrical energy, wherein the voltage converter module comprises a plurality of voltage conversion legs each respectively contributing a respective voltage into the auxiliary power bus, each of the conversion legs being coupled to a respective interface inductor through a respective first terminal of the inductor, each interface inductor having a respective second terminal coupled to one another at a common node;
• at least one inverter being coupled to the voltage converter module through the common node to drive the predetermined equipment on the auxiliary power bus at a selectable variable frequency independently of the RPM of the engine using the power captured during the predetermined mode of system operation;
• and
• an inverter module selectively coupled to drive the main alternator during an engine-cranking mode of operation.

A power system including an internal combustion engine coupled to drive a main alternator and an auxiliary alternator, the main alternator coupled to power one or more traction motors and the auxiliary alternator coupled to power predetermined electrical equipment, the system comprising:

• a main power bus generally powered by the main alternator;
• an auxiliary power bus generally powered by the auxiliary alternator;
• a power interface unit electrically coupled to the main power bus to capture and transfer electrical energy into the auxiliary power bus, at least some of the electrical energy being generated during a predetermined mode of operation of the system, wherein the power interface unit has a voltage converter module selectively coupled to impart a desired voltage conversion to voltage signals propagating between the main power bus and the auxiliary power bus to transfer the captured electrical energy to at least one of the following:
• the equipment on the auxiliary bus and an energy storage device;
• and
• at least one inverter coupled to the voltage converter module through a common node to drive the predetermined equipment using the power captured during the predetermined mode of system operation and provide selectably variable speed control to said equipment while decoupling undesired speed variation due to changes in rotational speed of the engine.