Bi-directional DC-DC power converter for a vehicle system

A vehicle system comprising:

• a direct current (DC) link;
• an energy storage device;
• a bi-directional DC-to-DC partial power converter coupled between the energy storage device and the DC link;
• and
• a controller configured to selectively operate the bi-directional DC-to-DC partial power converter in boost mode to boost a voltage from the energy storage device to the DC link and a buck mode to buck a voltage from the DC link to the energy storage device, the controller programmed to:
• determine a value of a processed portion of power received by the bi-directional DC-to-DC partial power converter;
• and
• determine a value of an unprocessed portion of power received by the bi-directional DC-to-DC partial power converter;
• wherein the values of the processed and unprocessed portions of power are based on a voltage differential between the energy storage device and the DC link.

A method of transferring power in a vehicle system that includes an energy storage device, a direct current (DC) link, a load, and a bi-directional DC-DC converter assembly, the method comprising:

• operating the bi-directional DC-DC converter assembly in a boost mode to boost a DC voltage from an output of the energy storage device to the DC link or in a buck mode to buck voltage from the DC link to the energy storage device;
• wherein operating the bi-directional DC-DC converter assembly in the boost mode or the buck mode comprises:
• determining a voltage differential between the energy storage device and the DC link;
• determining a first portion of power received by the bi-directional DC-DC converter assembly to be processed, so as to boost or buck the received power;
• determining a second portion of power received by the bi-directional DC-DC converter assembly to remain unprocessed;
• causing the bi-directional DC-DC converter assembly to process the first portion of the received power and leave the second portion of the received power unprocessed;
• and
• collectively outputting the processed first portion and unprocessed second portion from the bi-directional DC-DC converter assembly.

A vehicle system comprising:

• a direct current (DC) link;
• an energy storage device;
• and
• a bi-directional DC-DC converter coupled between the energy storage device and the DC link, the bi-directional DC-DC converter comprising:
• a first converter section coupled to the energy storage device;
• and
• a second converter section coupled to the DC link and the energy storage device;
• wherein the bi-directional DC-DC converter assembly is configured to:
• process a first portion of regenerative power received from the DC link, the processed first portion of regenerative power determined by a voltage differential between the energy storage device and the DC link;
• and
• provide the processed first portion of regenerative power and an unprocessed second portion of regenerative power to the first converter section, the unprocessed second portion of regenerative power also determined by the voltage differential.