초록 ▼

A vehicle propulsion includes an alternating current (AC) traction drive, a first energy storage system electrically coupled to the traction drive through a direct current (DC) link, a second energy storage system electrically coupled to the traction drive such that the voltage output from the secon

A vehicle propulsion includes an alternating current (AC) traction drive, a first energy storage system electrically coupled to the traction drive through a direct current (DC) link, a second energy storage system electrically coupled to the traction drive such that the voltage output from the second energy storage system is decoupled from the DC link using a bi-directional boost converter, and a uni-directional current device that is poled to conduct current from the low voltage side of the boost converter to the high voltage side of the boost converter.

대표청구항 ▼

What is claimed is: 1. A vehicle propulsion system comprising: an alternating current (AC) traction drive; a first energy storage system electrically coupled to said fraction drive through a direct current (DC) link; a second energy storage system electrically coupled to said traction drive such th

What is claimed is: 1. A vehicle propulsion system comprising: an alternating current (AC) traction drive; a first energy storage system electrically coupled to said fraction drive through a direct current (DC) link; a second energy storage system electrically coupled to said traction drive such that the voltage output from said second energy storage system is decoupled from said DC link using a bi-directional boost converter; and a uni-directional current device that is poled to conduct current from a low voltage side of a boost converter to a high voltage side of said boost converter, wherein said first energy storage system comprises a first ultracapacitor that is coupled on said boost converter high voltage side, wherein said second energy storage system comprises a second ultracapacitor and a high-specific energy battery that are each coupled on said boost converter low voltage side. 2. A vehicle propulsion system in accordance with claim 1 wherein said first ultracapacitor is comprised of multiple cells coupled in a series configuration with cell capacitance that is greater than 500 Farads. 3. A vehicle propulsion system in accordance with claim 1 wherein said second ultracapacitor has a voltage rating that is between approximately two and approximately three times greater than a nominal voltage rating of said high specific energy battery. 4. A vehicle propulsion system in accordance with claim 1 further comprising a second uni-directional current device that is poled to conduct current from said high specific energy battery to said second ultracapacitor coupled on said boost converter low voltage side. 5. A vehicle propulsion system in accordance with claim 1 wherein said first ultracapacitor has a voltage rating that is between approximately two and approximately three times greater than the maximum voltage rating of said second ultracapacitor. 6. A vehicle propulsion system in accordance with claim 1 further comprising a pre-charge circuit configured to at least partially pre-charge said first ultracapacitor. 7. A vehicle propulsion system in accordance with claim 6 further comprising a diode poled between said pre-charge circuit and said first ultracapacitor. 8. A vehicle propulsion system in accordance with claim 6 wherein said pre-charge circuit is configured to partially charge said first ultracapacitor utilizing said high-specific energy battery. 9. A vehicle comprising: a propulsion system comprising an alternating current (AC) traction drive; a first energy storage system electrically coupled to said traction drive through a direct current (DC) link; a second energy storage system electrically coupled to said traction drive such that the voltage output from the second energy storage system is decoupled from said DC link using a bi-directional boost converter; and a uni-directional current device that is poled to conduct current from a low voltage side of a boost converter to a high voltage side of said boost converter, wherein said first energy storage system comprises a first ultracapacitor that is coupled on said boost converter high voltage side, wherein said second energy storage system comprises a second ultracapacitor and a high-specific energy battery that are each coupled on said boost converter low voltage side. 10. A vehicle in accordance with claim 9 wherein said first ultracapacitor comprises multiple cells that are coupled in a series configuration, each said cell having a capacitance that is greater than 500 Farads. 11. A vehicle in accordance with claim 9 further comprising a second uni-directional current device that is poled to conduct current from said high specific energy battery to said second ultracapacitor coupled on said boost converter low voltage side. 12. A vehicle in accordance with claim 9 wherein said second ultracapacitor has a voltage rating that is between approximately two and approximately three times greater than the nominal voltage rating of said high specific energy battery. 13. A vehicle in accordance with claim 9 wherein said first ultracapacitor has a voltage rating that is between approximately two and approximately three times greater than the maximum voltage rating of said second ultracapacitor. 14. A vehicle in accordance with claim 9 further comprising a pre-charge circuit configured to at least partially pre-charge said first ultracapacitor. 15. A vehicle in accordance with claim 9 wherein said vehicle is a parallel hybrid vehicle. 16. A vehicle in accordance with claim 9 wherein said vehicle is an electric vehicle.