HYBRID VEHICLE POWER CONTROL SYSTEMS AND METHODS

• US 20040238243A1
• Filed: 06/02/2003
• Published: 12/02/2004
• Est. Priority Date: 06/02/2003
• Status: Active Grant

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: General Electric Company
• Inventors: Song, Dongwoo, Young, Henry Todd, Salasoo, Lembit, Kumar, Ajith Kuttannair, King, Robert Dean
• Granted Patent: US 8,025,115 B2
• Time in Patent Office: Days
• US Class Current: 180/65.2
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• 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 7/22 Dynamic electric resistor braking, combined with dynamic electric regenerative braking
• CPC Class Codes: H02J 7/1446 in response to parameters of a vehicle
• 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 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A method for controlling a power system of a hybrid vehicle includes determining, during a motoring mode of operation, a desired operating voltage of a direct current (DC) bus included in the power system at a given speed. The desired operating voltage is based on a minimum operating voltage at the given speed and a maximum operating voltage at the given speed, wherein an energy storage element parameter is used establishing the minimum operating voltage.

Claims

1. A method for controlling a power system of a hybrid vehicle, the method comprising:

during a motoring mode of operation, determining a desired operating voltage of a direct current (DC) bus included in the power system, at a given speed, said desired operating voltage being based on a minimum operating voltage at said given speed and a maximum operating voltage at said given speed;

wherein an energy storage element parameter is used establishing said minimum operating voltage.

2. The method of claim 1, wherein said energy storage element comprises one of a storage battery, an ultracapacitor, a flywheel and combinations comprising at least one of the foregoing.

3. The method of claim 1, wherein said minimum operating voltage is established by one of a minimum traction motor operating voltage, a minimum inverter operating voltage, and a minimum storage battery voltage.

4. The method of claim 3, wherein said maximum operating voltage is established by one of a maximum alternator operating voltage and a maximum inverter operating voltage.

5. The method of claim 4, further comprising applying an optimization function in determining said desired operating voltage, wherein said optimization function is dependent upon a chopper switching frequency and a ripple current of the power system.

6. The method of claim 5, wherein said optimization function is further dependent upon a state of power sharing between an engine driven alternator of the power system and said energy storage element.

7. The method of claim 1, wherein the hybrid vehicle comprises one of:

an off-highway vehicle (OHV) and a locomotive.

8. A method for controlling a power system of a hybrid vehicle, the method comprising:

during a dynamic braking mode of operation, configuring the power system so as to allow a storage battery to receive dynamic braking power outputted by a traction motor of the system, said battery receiving said dynamic braking power up to a first threshold level; and

for dynamic braking power levels in excess of said first threshold level, coupling one or more resistive grid elements in the power system to dissipate said excess power levels.

9. The method of claim 8, further comprising configuring one or more of at least one of a contactor and a chopper device within the power system so as to cause said coupling of said one or more resistive grid elements.

10. The method of claim 9, wherein said configuring one or more contactors within the power system is implemented so as to minimize cycling of said contactors over a range of dynamic braking power levels.

11. The method of claim 10, further comprising:

for dynamic braking power levels between said first threshold level and a second threshold level, engaging a first contactor associated with a first resistive grid so as to dissipate a first fixed amount of power therethrough;

for dynamic braking power levels between said second threshold level and a third threshold level, allowing said first resistive grid to dissipate an additional amount of power in excess of said first fixed amount of power therethrough;

for dynamic braking power levels between said third threshold level and a fourth threshold level, engaging a chopper device associated with a second resistive grid so as to allow said second resistive grid to dissipate an additional amount of power in excess of said third threshold level therethrough, and said first resistive grid dissipating a second fixed amount of power therethrough;

for dynamic braking power levels between said fourth threshold level and a fifth threshold level, engaging a second contactor associated with a third resistive grid; and

for dynamic braking power levels over said fifth threshold level, engaging said chopper device associated with said second resistive grid.

12. The method of claim 9, wherein said configuring one or more contactors within the power system is implemented so as to minimize the increase in a DC bus voltage of the power system.

13. The method of claim 12, further comprising:

for dynamic braking power levels between said first threshold level and a second threshold level, engaging a first contactor associated with a first resistive grid so as to dissipate a first fixed amount of power therethrough;

for dynamic braking power levels between said second threshold level and a third threshold level, engaging a chopper device associated with a second resistive grid so as to allow said second resistive grid to dissipate an additional amount of power in excess of said second threshold level therethrough; and

for dynamic braking power levels between said third threshold level and a fourth threshold level, engaging a second contactor associated with a third resistive grid;

wherein said DC bus voltage of the power system remains at a substantially constant value for dynamic braking power levels up to said fourth threshold level.

14. The method of claim 8, wherein the hybrid vehicle comprises one of:

an off-highway vehicle (OHV) and a locomotive.

15. A method for controlling a power system of a hybrid vehicle, the method comprising:

determining, for a first bus voltage, a point of operation at which a power generation capability of a traction motor of the power system is equal to a power dissipation capability of one or more resistive grid elements in the power system; and

at about said point of operation, increasing said first bus voltage to a second bus voltage.

16. The method of claim 15, wherein said point of operation represents an operating speed of said traction motor, said first bus voltage corresponds to a first DC link voltage utilized when said traction motor is at speeds below said point of operation, and second bus voltage corresponds to a second DC link voltage utilized when said traction motor is at speeds above said point of operation.

17. The method of claim 15, wherein said increasing said first bus voltage to said second bus voltage is implemented through power from an energy storage device of the vehicle.

18. The method of claim 15, wherein the hybrid vehicle comprises one of:

an off-highway vehicle (OHV) and a locomotive.

19. A method for controlling engine power of a hybrid vehicle, the method comprising:

determining a power demand from a traction drive of the vehicle;

determining an average of auxiliary power loads of the vehicle;

and

determining an engine control speed set point, said engine control speed set point producing a desired engine speed, a desired torque, a desired total power output and a desired specific fuel consumption;

wherein said desired total output corresponds to said power demand from said traction drive plus said average of auxiliary power loads.

20. The method of claim 19, wherein variations to the engine power for operation at said engine speed control set point are implemented through a torque control feature of the vehicle.

21. The method of claim 20, wherein:

variations in said total power demand below a threshold level are compensated by said torque control feature; and

variations in said total power demand above said threshold level are compensated by adjusting said engine speed set point.

22. The method of claim 21, wherein said torque control feature is provided by an electronic control module (ECM) of the vehicle.

23. The method of claim 19, wherein the hybrid vehicle comprises one of:

an off-highway vehicle (OHV) and a locomotive.

24. A power control system for a hybrid vehicle, comprising:

an electronic control module (ECM) configured for receiving a signal representative of a power demand from a traction drive of the vehicle;

said ECM further configured for receiving a signal representative of an average of auxiliary power loads of the vehicle; and

said ECM further configured for generating an engine control speed set point, said engine control speed set point producing a desired engine speed, a desired torque, a desired total power output and a desired specific fuel consumption;

wherein said desired total output corresponds to said power demand from said traction drive plus said average of auxiliary power loads.

25. The power control system of claim 24, wherein variations to the engine power for operation at said engine speed control set point are implemented through a torque control feature of said ECM.

26. The power control system of claim 25, wherein:

variations in said total power demand below a threshold level are compensated by said torque control feature of said ECM; and

variations in said total power demand above said threshold level are compensated by an adjustment of said engine speed set point by said ECM.

27. The power control system of claim 24, wherein the hybrid vehicle comprises one of:

an off-highway vehicle (OHV) and a locomotive.

29. The method of claim 24, further comprising:

following said determining a mode of operation in which engine output power levels are below a threshold value, determining whether the temperature of said vehicle catalyst is below a minimum operational threshold value;

wherein said stored energy is used to heat said vehicle catalyst if said the temperature of said vehicle catalyst is below said minimum operational threshold value.

28. A method for controlling catalyst temperature of an exhaust system for a hybrid vehicle, the method comprising:

determining a mode of operation in which engine output power levels are below a threshold value; and

using stored energy within an energy storage system of the vehicle to heat a vehicle exhaust catalyst whenever said engine output levels are below a threshold value.