VEHICLE PROPULSION SYSTEM

• US 20070164693A1
• Filed: 12/21/2006
• Published: 07/19/2007
• Est. Priority Date: 01/18/2006
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Huang, Xianghui, King, Robert Dean, Kilinski, Gary Raymond
• Granted Patent: US 7,595,597 B2
• Time in Patent Office: Days
• US Class Current: 318/109
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/06 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/24 with additional mechanical or electromagnetic braking
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: B60Y 2400/114 Super-capacities
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

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 bidirectional 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.

Claims

1. A vehicle propulsion system comprising:

an alternating current (AC) traction drive system;

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 said second energy storage system is decoupled from said DC link using a bi-directional boost converter comprising a high voltage side and a low voltage side; 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.

2. A vehicle propulsion system in accordance with claim 1, wherein said first energy storage system comprises at least one of a first ultracapacitor and a first high specific power battery that are each coupled on said boost converter high voltage side.

3. A vehicle propulsion system in accordance with claim 1, wherein said second energy storage system comprises at least one of a second ultracapacitor and a second high specific energy battery that are each coupled on said boost converter low voltage side.

4. A vehicle propulsion system in accordance with claim 3, wherein said second high specific energy battery comprises at least one of a sodium metal halide battery, a sodium nickel chloride battery, a sodium sulfur battery, a lithium-ion battery, a lithium polymer battery, a nickel metal hydride battery, a nickel cadmium battery, and a lead acid battery.

5. A vehicle propulsion system in accordance with claim 3 wherein said second ultracapacitor has a voltage rating that is between approximately two and approximately twenty five times greater than a nominal voltage rating of said second high specific energy battery.

6. A vehicle propulsion system in accordance with claim 2 wherein said first ultracapacitor has a voltage rating that is between approximately two and approximately four times greater than the maximum voltage rating of said second ultracapacitor.

7. A vehicle propulsion system in accordance with claim 2 further comprising a pre-charge circuit configured to at least partially charge said first ultracapacitor.

8. A vehicle propulsion system in accordance with claim 7 further comprising a diode poled between said pre-charge circuit and said first ultracapacitor.

9. A vehicle propulsion system in accordance with claim 1, further comprising a current sensor coupled to said direct current link, said energy management system configured to receive an output from said current sensor 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.

10. A vehicle propulsion system in accordance with claim 9, further comprising a voltage sensor coupled to said direct current 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 a pre-charge mode and a normal operation mode with the traction drive system enabled.

11. A vehicle propulsion system in accordance with claim 10, wherein said energy management system comprises an algorithm programmed to receive an output from said current sensor, filter said current sensor output, and use said filtered current sensor output to generate a first component utilized to compute a traction drive load power.

12. A vehicle propulsion system in accordance with claim 11, wherein algorithm is further programmed to receive an output from said voltage sensor, and use said voltage sensor output to generate a second component utilized to compute said traction drive load power.

13. A vehicle propulsion system in accordance with claim 12, wherein said algorithm is further programmed to multiply said first component with said second component to compute said traction drive load power.

14. A vehicle propulsion system in accordance with claim 13, 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 the maximum rated motor speed to generate a percent motor rated speed signal that is one input to a two dimensional look-up table, whereas said computed traction drive load power signal is a second input to said look-up table, whereas 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.

15. A vehicle propulsion system in accordance with claim 14, 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 said DC bus voltage sensor to drive the high side voltage side of said traction drive system towards a varying DC bus reference voltage.

16. A vehicle propulsion system in accordance with claim 15, wherein said algorithm further comprises a second subroutine programmed to receive an input from a direct current bus current sensor, and based on this signal generate an adjustable gain signal that is based on the value of the direct current bus voltage and a specific mode of operation signal.

17. A vehicle propulsion system in accordance with claim 16, 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 the direct current link voltage exceeds a predetermined voltage upper limit.

18. A vehicle propulsion system in accordance with claim 17, wherein said algorithm is further programmed to sum the 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.

19. A vehicle propulsion system in accordance with claim 1, wherein said energy management system is programmed to generate a power command signal to control the relative power between said second ultracapacitor and said second high specific energy battery as a function of an operational mode of the said vehicle, said second ultracapacitor voltage and an ampere hour rating of said second high specific energy battery.

20. A vehicle propulsion system in accordance with claim 19, wherein said operational mode comprises at least one of a motoring mode and a regenerating mode.

21. A vehicle propulsion system in accordance with claim 19, wherein said energy management system is programmed to utilize a piecewise linear power limit function to generate a power command signal.

22. A vehicle propulsion system in accordance with claim 19, wherein said energy management system is further programmed to utilize a computed ampere hour value of said second high specific energy battery and an ampere hour rating of said second high specific energy battery to determine a relative power split between said second ultracapacitor and said second high specific energy battery.

23. A vehicle propulsion system in accordance with claim 19, wherein said energy management system is further programmed to generate a signal to initiate an additional energy storage charge command whenever the ampere hour value of said second high specific energy battery is less than a predetermined value.

24. A vehicle propulsion system in accordance with claim 2, further comprising a precharge circuit configured to at least partially charge said first ultracapacitor.

25. A vehicle propulsion system in accordance with claim 22, wherein said precharge circuit is further configured to precharge a filter capacitor to a voltage that is within a given threshold of the voltage on said second ultracapacitor on one or more phases of a multi-phase traction boost converter.

26. A vehicle propulsion system in accordance with claim 1, further comprising a DC-DC converter electrically coupled to a vehicle alternator rectifier output and a vehicle starting, lighting, and ignition battery providing low-level charge of a high specific energy battery coupled on said low voltage side of the traction boost converter with galvanic isolation provided between a vehicle chassis and a plurality of high-voltage traction electrical components

27. A vehicle propulsion system in accordance with claim 24, wherein said energy management system is configured to control said precharge circuit when said second ultracapacitor is operating at a relatively low voltage.

28. A vehicle propulsion system in accordance with claim 1, further comprising:

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 temperature sensor to facilitate cooling at least one of said first and second energy storage units.

29. A vehicle propulsion system in accordance with claim 28, 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.

30. A vehicle propulsion system in accordance with claim 28, wherein said at least one cooling fan is activated using power supplied from either the first or second storage units when said traction drive is disabled or enabled.

31. A vehicle propulsion system in accordance with claim 28, 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 traction drive is enabled.