Method and apparatus for adaptive control of vehicle regenerative braking

• US 20040207350A1
• Filed: 04/15/2003
• Published: 10/21/2004
• Est. Priority Date: 12/27/2000
• Status: Abandoned Application

• Current Assignee: Transportation Technologies, LLC
• Original Assignee: Transportation Technologies, LLC
• Inventors: Schmitz, Robert W., Anderson, Joshua J., Wilton, Thomas F.
• Application Number:
  US10/413,544
• Publication Number:
  US 20040207350A1
• Time in Patent Office: Days
• US Class Current: 318/376
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/16 DC brushless machines
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0061 relating to electrical machines
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 3/102 of individual wheels
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• 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

Abstract

A hybrid electric vehicle having an energy generation system, an energy storage system and at least one electric motor includes a controller for controlling operation of vehicle systems. The controller monitors the status of vehicle systems and system parameters and determines the regenerative braking mode of the vehicle and the appropriate level of regenerative braking for proper vehicle operation. The controller generates commands based upon these determinations to produce regenerative braking, monitors the status to determine the effects of the regenerative braking command generated, and adaptively changes the regenerative braking command generated in response to the measured effects. A method for adaptively controlling a hybrid electric vehicle is also provided.

Claims

1. A method for adaptively controlling a hybrid electric vehicle including an energy generation system, an energy storage system receiving electric current at least from the energy generation system, and at least one electric drive motor receiving current from the energy storage system, comprising:

monitoring the status of various vehicle systems;

monitoring user inputs for removal of acceleration command inputs and application of braking inputs;

determining if the vehicle is in one of a plurality of regenerative braking modes, including determining which regenerative braking mode the vehicle is in;

determining an appropriate level of regenerative braking to be applied in a braking event, given the monitored status of vehicle systems and the determination of the regenerative braking mode;

generating a command signal to the electric drive motor to generate the determined level of regenerative braking;

determining the effect of the regenerative braking command on the status of the vehicle systems; and

adaptively generating further command signals to the electric drive motor altering the level of regenerative braking applied.

2. The method of claim 1, wherein a state of charge of the energy storage system is monitored and the step of determining an appropriate level of regenerative braking to be applied is determined based on the monitored state of charge and the determined regenerative braking mode.

3. The method of claim 1, further comprising:

monitoring for the signal of one or more vehicle fault states;

determining if a fault state is related to energy storage or drive motor systems; and

reducing or eliminating regenerative braking commands if the fault is related to energy storage or drive motor systems.

4. The method of claim 1, further comprising:

monitoring the temperature of energy storage, electric drive motor, and/or cooling systems temperatures;

reducing or eliminating regenerative braking commands if one or more monitored temperatures are above a predetermined level; and

increasing regenerative braking commands if one or more monitored temperatures are below a predetermined level.

5. The method of claim 1, further comprising:

monitoring for a signal indicating that vehicle anti-lock braking or traction control systems are actively affecting vehicle braking or propulsion; and

reducing or eliminating regenerative braking commands if one or more of the monitored systems are active.

6. The method of claim 1, further comprising:

monitoring the rotational speeds or one or more driving wheels;

determining if monitored wheel rotation velocity exceeds an expected velocity range relative to other monitored wheels or to a predicted velocity;

generating a greater regenerative braking command to reduce wheel rotation velocity if the monitored velocity is greater than an expected upper velocity limit; and

generating a reduced regenerative braking command to reduce de-acceleration of wheel rotational velocity if the monitored velocity is less than an expected lower velocity limit.

7. The method of claim 1, wherein the vehicle further includes an electrical load bank for dissipation of electrical energy to heat or mechanical work, and the method further comprises:

monitoring a state of charge of the energy storage system;

monitoring when regenerative braking commands are active;

determining when the state of charge of the energy storage system meets or exceeds an upper limit and regenerative braking is active;

generating a command to allow electrical energy created by regenerative braking to be diverted to the electrical load bank; and

reducing or eliminating the command allowing electrical energy to be diverted to the electrical load bank upon reduction or elimination of the regenerative braking command.

8. The method of claim 1, further comprising:

determining if the vehicle is in at least one of a first regenerative braking mode, a second regenerative braking mode and a third regenerative braking mode;

decreasing regenerative braking, if the vehicle is in the first regenerative braking mode;

decreasing regenerative braking if a battery state of charge is approaching an upper control limit and the vehicle is in the second regenerative braking mode;

increasing regenerative braking if the battery state of charge is approaching a lower control limit and the vehicle is in the second regenerative braking mode; and

increasing regenerative braking, if the vehicle is in the third regenerative braking mode.

9. A hybrid electric vehicle, comprising:

an energy generation system;

an energy storage system receiving electric current at least from the generation system;

at least one electric motor receiving current from the energy storage system; and

a vehicle controller that;

monitors a status of various vehicle systems;

monitors user inputs for removal of acceleration command inputs and application of braking inputs;

determines if the vehicle is in one of a plurality of regenerative braking modes, including determining which regenerative braking mode the vehicle is in;

determines an appropriate level of regenerative braking to be applied in a braking event, given the monitored status of vehicle systems and the determination of the regenerative braking mode;

generates a command signal to the electric drive motor to generate the determined level of regenerative braking;

determines an effect of the regenerative braking command on the status of the vehicle systems; and

adaptively generates further command signals to the electric drive motor altering the level of regenerative braking applied.

10. The hybrid electric vehicle of claim 9, wherein the controller:

monitors a state of charge of the energy storage system and determines the appropriate level of regenerative braking to be applied based on the monitored state of charge and determined regenerative braking mode.

11. The hybrid electric vehicle of claim 9, wherein the controller:

monitors for the signal of one or more vehicle fault states;

determines if the fault state is related to energy storage or drive motor systems; and

reduces or eliminates regenerative braking commands if the fault is related to energy storage or drive motor systems.

12. The hybrid electric vehicle of claim 9, wherein the controller:

monitors the temperature of energy storage, electric drive motor, and/or cooling systems temperatures;

reduces or eliminates regenerative braking commands if one or more monitored temperatures are above a predetermined level; and

increases regenerative braking commands if one or more monitored temperatures are below a predetermined level.

13. The hybrid electric vehicle of claim 9, wherein the controller:

monitors for a signal indicating that vehicle anti-lock braking or traction control systems are actively affecting vehicle braking or propulsion; and

reduces or eliminates regenerative braking commands if one or more monitored systems are active.

14. The hybrid electric vehicle of claim 9, wherein the controller:

monitors rotational speeds or one or more driving wheels;

determines if the monitored wheel rotation velocity exceeds an expected velocity range relative to other monitored wheels or to a predicted velocity;

generates a greater regenerative braking command to reduce wheel rotation velocity if the monitored velocity is greater than an expected upper velocity limit; and

generates a reduced regenerative braking command to reduce de-acceleration of wheel rotational velocity if the monitored velocity is less than an expected lower velocity limit.

15. The hybrid electric vehicle of claim 9, wherein an electrical load bank is available for dissipation of electrical energy to heat or mechanical work and wherein the controller:

monitors a state of charge of the energy storage system;

monitors when regenerative braking commands are active;

determines when the state of charge of the energy storage system meets or exceeds an upper limit and regenerative braking is active;

generates a command to allow electrical energy created by regenerative braking to be diverted to the electrical load bank; and

reduces or eliminates the command allowing electrical energy to be diverted to the electrical load bank upon reduction or elimination of the regenerative braking command.

16. The hybrid electric vehicle of claim 9, wherein the controller:

determines if the vehicle is in at least one of a first regenerative braking mode, a second regenerative braking mode and a third regenerative braking mode;

decreases regenerative braking, if the vehicle is in the first regenerative braking mode;

decreases regenerative braking if a battery state of charge is approaching an upper control limit and the vehicle is in the second regenerative braking mode;

increasing regenerative braking if the battery state of charge is approaching a lower control limit and the vehicle is in the second regenerative braking mode; and

increases regenerative braking, if the vehicle is in the third regenerative braking mode.

17. A method for adaptively controlling propulsion of a hybrid electric vehicle including an energy generation system, an energy storage system receiving electric current at least from the energy generation system, and at least one electric drive motor receiving current from the energy storage system, comprising:

generating a first signal having a value indicative of an accelerator command to a controller;

generating a second signal having a value proportional to the first signal and indicative of a demand of the at least one electric drive motor from the controller to a motor controller;

determining if the value of the first signal is smaller than the value of the second signal;

increasing the value of a command signal to the at least one electric motor, if the value of the first signal is not smaller than the value of the second signal; and

decreasing the value of the command signal, if the value of the first signal is smaller than the value of the second signal.

18. A hybrid electric vehicle, comprising:

an energy generation system;

an energy storage system receiving current at least from the energy generation system;

at least one electric drive motor receiving current from the energy storage system;

at least one motor controller that controls the at least one electric drive motor;

a sensor that generates a first signal having a value indicative of an accelerator command; and

a controller that;

receives the first signal from the sensor;

generates a second signal having a value proportional to the first signal and indicative of a demand of the at least one electric drive motor and sends the second signal to the motor controller;

determines if the value of the first signal is smaller than the value of the second signal;

increases the value of a command signal to operate the at least one electric motor, if the value of the first signal is not smaller than the value of the second signal; and

decreases the value of the command signal, if the value of the first signal is smaller than the value of the second signal.

19. The hybrid electric vehicle of claim 18, wherein the energy generation system includes an internal combustion engine connected to a generator.

20. The hybrid electric vehicle according to claim 19, wherein the energy storage system includes a battery array.

21. The hybrid electric vehicle according to claim 19, wherein the vehicle is a series type hybrid.