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 an energy management system configured to control said first and second energy storage systems when the vehicle is operating in at least one of a pre-charge mode and a normal operation mode with the traction drive system enabled.

대표청구항 ▼

What is claimed is: 1. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost converter electrically coupled to said AC traction drive system; a firs

What is claimed is: 1. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost converter electrically coupled to said AC traction drive system; a first energy storage system including a direct current (DC) link electrically coupling said first energy storage system to said AC traction drive system, said first energy storage system comprising at least one of a first ultracapacitor and a first high specific power battery coupled on said high voltage side; a second energy storage system electrically coupled to said AC traction drive system such that a voltage output from said second energy storage system is decoupled from said DC link using said bi-directional boost converter; an energy management system configured to control said first and second energy storage systems when a vehicle is operating in at least one of a pre-charge mode and a normal operation mode with said AC traction drive system enabled; and a pre-charge circuit configured to at least partially charge said first ultracapacitor. 2. A vehicle propulsion system in accordance with claim 1 further comprising a diode poled between said pre-charge circuit and said first ultracapacitor. 3. A vehicle propulsion system in accordance with claim 1, wherein said energy management system is configured to control said pre-charge circuit when said first ultracapacitor is operating at a relatively low voltage. 4. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost converter electrically coupled to said AC traction drive system; a first energy storage system electrically coupled to said AC traction drive system through a direct current (DC) link; a second energy storage system electrically coupled to said AC traction drive system such that a voltage output from said second energy storage system is decoupled from said DC link using said bi-directional boost converter; a current sensor coupled to said DC link; and an energy management system configured to receive an output from said current sensor to control said first and second energy storage systems when a vehicle is operating in at least one of a pre-charge mode and a normal operation mode with said AC traction drive system enabled. 5. A vehicle propulsion system in accordance with claim 4, further comprising a voltage sensor coupled to said DC link, said energy management system configured to receive an output from said voltage sensor to control said first and second energy storage systems when the vehicle is operating in at least one of the pre-charge mode and the normal operation mode with said AC traction drive system enabled. 6. A vehicle propulsion system in accordance with claim 5, wherein said energy management system comprises an algorithm programmed to receive said current sensor output, filter said current sensor output, and use said filtered current sensor output to generate a first component utilized to compute an AC traction drive system load power. 7. A vehicle propulsion system in accordance with claim 6, wherein said algorithm is further programmed to receive said voltage sensor output, and use said voltage sensor output to generate a second component utilized to compute said AC traction drive system load power. 8. A vehicle propulsion system in accordance with claim 7, wherein said algorithm is further programmed to multiply said first component with said second component to compute said AC traction drive system load power. 9. A vehicle propulsion system in accordance with claim 8, wherein said energy management system is further configured to receive a filtered traction motor speed signal, said algorithm is further programmed to divide the filtered traction motor speed signal by a maximum rated motor speed to generate a percent motor rated speed signal that is one input to a two dimensional look-up table, said computed traction drive system load power signal is a second input to said look-up table, and said look-up table is configured to provide a DC bus reference voltage command output signal that varies as a function of motor speed for a family of motor torque curves in an optimized manner that minimize motor and drive component system losses to improve drive system efficiency during low-speed operation and light torque operation as well as during medium and high power traction drive operation. 10. A vehicle propulsion system in accordance with claim 9, wherein said algorithm comprises a first subroutine that includes a proportional-integral controller that sums the DC bus reference voltage command output signal and an input from a direct current (DC) bus voltage sensor to drive the high voltage side of said AC traction drive system towards a varying DC bus reference voltage. 11. A vehicle propulsion system in accordance with claim 10, wherein said algorithm further comprises a second subroutine programmed to receive an input from a direct current bus current sensor, and based on the input generate an adjustable gain signal that is based on a value of a direct current bus voltage and a specific mode of operation signal. 12. A vehicle propulsion system in accordance with claim 11, wherein said algorithm further comprises a third subroutine programmed to reduce a portion of a total power command signal transmitted to said energy management system when a direct current link voltage exceeds a predetermined voltage upper limit. 13. A vehicle propulsion system in accordance with claim 12, wherein said algorithm is further programmed to sum outputs from said first, second, and third subroutines, and pass the summed outputs through an asymmetric limiter to generate a total energy management system power command. 14. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost convertor electrically coupled to said AC traction drive system; a first energy storage system electrically coupled to said AC traction drive system through a direct current (DC) link; a second energy storage system electrically coupled to said AC traction drive system, a voltage output from said second energy storage system decoupled from said DC link using said bi-directional boost converter, said second energy storage system comprising at least one of an ultracapacitor and a high specific energy battery coupled on said low voltage side; and an energy management system configured to control said first and second energy storage systems when a vehicle is operating in at least one of a pre-charge mode and a normal operation mode with said AC traction drive system enabled, wherein said energy management system is programmed to generate a power command signal to control a relative power between said ultracapacitor and said high specific energy battery as a function of an operational mode of the vehicle, an ultracapacitor voltage and an ampere hour rating of said high specific energy battery. 15. A vehicle propulsion system in accordance with claim 14, wherein said operational mode comprises at least one of a motoring mode and a regenerating mode. 16. A vehicle propulsion system in accordance with claim 14, wherein said energy management system is further programmed to utilize a piecewise linear power limit function to generate a power command signal. 17. A vehicle propulsion system in accordance with claim 14, wherein said energy management system is further programmed to utilize a computed ampere hour value of said high specific energy battery and the ampere hour rating of said high specific energy battery to determine a relative power split between said ultracapacitor and said high specific energy battery. 18. A vehicle propulsion system in accordance with claim 17, wherein said bi-directional boost converter comprises a multi-phase boost converter and a precharge circuit, said precharge circuit is configured to precharge a filter capacitor to a voltage that is within a given threshold of a voltage on said ultracapacitor on one or more phases of said multi-phase boost converter. 19. A vehicle propulsion system in accordance with claim 14, wherein said energy management system is further programmed to generate a signal to initiate an additional energy storage charge command whenever an ampere hour value of said high specific energy battery is less than a predetermined value. 20. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost converter electrically coupled to said AC traction drive system; a first energy storage system electrically coupled to said AC traction drive system through a direct current (DC) link; a second energy storage system electrically coupled to said AC traction drive system such that a voltage output from said second energy storage system is decoupled from said DC link using said bi-directional boost converter; an energy management system configured to control said first and second energy storage systems when a vehicle is operating in at least one of a pre-charge mode and a normal operation mode with said AC traction drive system enabled; and a DC-DC converter electrically coupled to a vehicle alternator rectifier output and a vehicle starting, lighting, and ignition battery providing a low-level charge of a high specific energy battery coupled on said low voltage side of said bi-directional boost converter with galvanic isolation provided between a vehicle chassis and a plurality of high-voltage traction electrical components. 21. A vehicle propulsion system comprising: an alternating current (AC) traction drive system; a bi-directional boost converter comprising a high voltage side and a low voltage side, said bi-directional boost converter electrically coupled to said AC traction drive system; a first energy storage system electrically coupled to said AC traction drive system through a direct current (DC) link; a second energy storage system electrically coupled to said AC traction drive system such that a voltage output from said second energy storage system is decoupled from said DC link using said bi-directional boost converter; an energy management system configured to control said first and second energy storage systems when a vehicle is operating in at least one of a pre-charge mode and a normal operation mode with said AC traction drive system enabled; at least one cooling fan; and at least one temperature sensor, said energy management system configured to operate said at least one cooling fan based on an output from said at least one temperature sensor to facilitate cooling at least one of said first and second energy storage systems. 22. A vehicle propulsion system in accordance with claim 21, further comprising a DC-DC converter coupled to said at least one cooling fan, said DC-DC converter configured to isolate said at least one cooling fan from a plurality of high-voltage traction electrical components. 23. A vehicle propulsion system in accordance with claim 21, wherein said at least one cooling fan is activated using power supplied from one of said first and second energy storage systems when said AC traction drive system is disabled or enabled. 24. A vehicle propulsion system in accordance with claim 21, wherein at least one of said first and second energy storage systems is recharged to a predetermined voltage level during normal operation using regenerative energy captured during vehicle deceleration and while engine charging when said AC traction drive system is enabled.