Systems and methods for control of powertrains with regenerative start/stop alternator functionality

• US 9,162,669 B2
• Filed: 02/25/2014
• Issued: 10/20/2015
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Dziuba, Robert, Leonarski, Jaroslaw
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): RINK, RYAN J
• Application Number:
  US14/189,245
• Publication Number:
  US 20150239457A1
• Time in Patent Office: 602 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2030/206 related or induced by the engine
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: B60W 2510/248 Age of storage means
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

Systems and methods are disclosed for controlling a torque output of a motor/generator via one or more torque commands generated by a controller. The target output being determined by a target torque based upon a low voltage side target of a DC/DC converter including a battery operatively coupled to one or more low voltage loads, a high voltage side target of the DC/DC converter including a supercapacitor operatively coupled with an inverter that is operatively coupled to the motor/generator, and a ripple compensation torque.

Claims

1. A system, comprising:

an engine having an output shaft;

a motor/generator operatively coupled with the output shaft;

an RSSA electronics module comprising an inverter operatively coupled with the motor/generator, a DC link including a supercapacitor, the DC link operatively coupled with the inverter, and a DC/DC converter including a high voltage side operatively coupled with the DC link and a low voltage side;

a low voltage power system, including a battery, operatively coupled with the low voltage side of the DC/DC converter; and

a controller configured to receive a torque request input and selectably control the system to operate in a generator mode and an engine assist mode in response to the torque request input;

wherein the controller operating in the generator mode is further configured to;

determine a low voltage side target of the DC/DC converter based upon one or more low voltage side conditions of the DC/DC converter and/or one or more high voltage side conditions of the DC/DC converter,

determine a first high voltage side target of the DC/DC converter based upon the low voltage side target and the one or more of the low voltage side conditions and/or the one or more high voltage side conditions,

determine a first target motor/generator torque based upon a ripple compensation torque and at least one of the low voltage side target and the high voltage side target, and

control the torque provided to the motor/generator based upon the first target motor/generator torque.

2. The system of claim 1, wherein the one or more low voltage side conditions includes a plurality of conditions including a low voltage power system power demand, a state of charge of the battery, a state of health of the battery, a voltage of the battery, a low voltage side current, a low voltage side voltage, and a cell temperature of the battery.

3. The system of claim 2, wherein the low voltage power system power demand accounts for a power required by one or more loads on the low voltage power system.

4. The system of claim 1, wherein the one or more high voltage side conditions includes a plurality of conditions including a high voltage side voltage, a high voltage side current, a state of charge of the supercapacitor, and a state of health of the supercapacitor.

5. The system of claim 1, wherein the first high voltage side target is further determined based upon a motor/generator speed.

6. The system of claim 1, wherein the first target motor/generator torque is further determined based upon a motor/generator speed, an engine load, and a machine load.

7. The system of claim 1, wherein the low voltage side target comprises a voltage output of the DC/DC converter and the first high voltage side target comprises a voltage output of the inverter.

8. The system of claim 1, wherein the controller operating in the engine assist mode is further configured to:

determine a second target motor/generator torque based upon the ripple compensation torque and an engine assistance torque, and

determine a second high voltage side target of the DC/DC converter based upon the second target motor/generator torque, an efficiency criterion for the supercapacitor, and the one or more of the low voltage side conditions and/or the one or more high voltage side conditions.

9. The system of claim 8, wherein the ripple compensation torque is determined based upon a high voltage side current, a high voltage side voltage, the engine assistance torque, a motor/generator condition, and an engine cylinder count.

10. The system of claim 9, wherein the motor/generator condition includes a motor/generator speed, a motor/generator rotor position, a motor/generator stator slot count, a pole-pairs count, and a motor/generator phase count.

11. The system of claim 8, wherein the low voltage side target, the first high voltage side target, and/or the second high voltage side target is further determined from a multi-dimensional lookup table output including two or more condition inputs selectable from the low voltage side conditions and the high voltage side conditions.

12. The system of claim 1, wherein the controller is further configured to select the system to operate in the generator mode in response to the torque request input being less than zero and a state of charge of the battery being less than a predetermined maximum state of charge threshold.

13. The system of claim 1, wherein the controller is further configured to select the system to operate in the engine assist mode in response to the torque request input being greater than zero and a state of charge of the battery being greater than a predetermined minimum state of charge threshold.

14. The system of claim 1, wherein the controller is further configured to control the system to operate in an engine start mode, wherein the controller operating in the engine start mode is configured to:

determine a supercapacitor energy level,

provide a charge command to the supercapacitor in response to the supercapacitor energy level being less than a predetermined minimum energy threshold, and

provide a crank command to the engine in response to the supercapacitor energy level being greater than the predetermined minimum energy threshold.

15. The system of claim 1, wherein the motor/generator comprises one of a switched reluctance motor/generator, an induction reluctance motor/generator, and a synchronous reluctance motor/generator, and the RSSA electronics module is structured as a unitary module.

16. A method, comprising:

providing a motor/generator operatively coupled with an output shaft of an engine, an inverter operatively coupled with the motor/generator, a DC link including a supercapacitor operatively coupled with the inverter, a DC/DC converter including a high voltage side operatively coupled with the DC link and a low voltage side, a low voltage power system including a battery operatively coupled with the low voltage side of the DC/DC converter, and a controller;

determining an available power level based upon a power level of the supercapacitor and a power level of the battery;

determining a first target output in response to the available power level being greater than zero and a battery efficiency criterion;

determining a second target output based upon the first target output and a supercapacitor efficiency criterion;

determining a target torque for a motor/generator based upon a ripple compensation torque and at least one of the first target output and the second target output;

setting the DC/DC converter to operate in a generator mode; and

controlling the torque output of the motor/generator via one or more torque commands generated by the controller based upon the target torque.

17. The method of claim 16, wherein the battery efficiency criterion is a function of at least two of a power demand required by one or more low voltage loads, one or more battery conditions, one or more low voltage side conditions of the DC/DC converter, and a high voltage side voltage of the DC/DC converter.

18. The method of claim 17, wherein the one or more battery conditions includes a plurality of conditions including a state of charge of the battery, a state of health of the battery, a voltage of the battery, and a cell temperature of the battery.

19. The method of claim 17, wherein the one or more low voltage side conditions includes a plurality of conditions including a low voltage side current and a low voltage side voltage.

20. The method of claim 17, wherein the supercapacitor efficiency criterion is a function of at least two of a power demand required by one or more low voltage loads, a voltage of the battery, one or more supercapacitor conditions, a low voltage side current of the DC/DC converter, one or more high voltage side conditions of the DC/DC converter, and a motor/generator speed.

21. The method of claim 20, wherein the one or more supercapacitor conditions includes a plurality of conditions including a state of charge of the supercapacitor and a state of health of the supercapacitor.

22. The method of claim 20, wherein the one or more high voltage side conditions includes a plurality of conditions including a high voltage side voltage and a high voltage side current.

23. The method of claim 17, wherein the first target output comprises a voltage of the battery and the second target output comprises a voltage of the supercapacitor.

24. A method, comprising:

providing a motor/generator operatively coupled with an output shaft of an engine, an RSSA electronics unit comprising an inverter operatively coupled with the motor/generator, a DC link including a supercapacitor operatively coupled with the inverter, a DC/DC converter including a high voltage side operatively coupled with the DC link and a low voltage side, a low voltage power system including a battery operatively coupled with the low voltage side of the DC/DC converter, and a controller;

determining an available power level based upon a supercapacitor power level and a battery power level;

determining a target torque for the motor/generator in response to the available power level being greater than zero, an engine assistance torque, and a ripple compensation torque;

determining a target output based upon the target torque and a supercapacitor efficiency criterion;

setting the DC/DC converter to operate in an engine assist mode; and

controlling the torque of the motor/generator via one or more torque commands generated by the controller based upon the target output.

25. The method of claim 24, wherein the supercapacitor efficiency criterion is a function of at least two of a power demand required by one or more low voltage loads, a voltage of the battery, a state of charge of the supercapacitor, a state of health of the supercapacitor, a low voltage side current of the DC/DC converter, a high voltage side voltage, a high voltage side current, and a motor/generator speed.

26. The method of claim 24, wherein the target output comprises a voltage level of the supercapacitor.

27. The method of claim 24, further comprising setting a current to the supercapacitor based upon a target low voltage battery current.

28. The method of claim 24, further comprising setting an voltage output from the supercapacitor based upon a target inverter voltage output.

29. The method of claim 24 wherein the RSSA electronics unit is provided as a closed structural package.