Vehicle propulsion system having an energy storage system and optimized method of controlling operation thereof

• US 9,783,185 B2
• Filed: 09/08/2014
• Issued: 10/10/2017
• Est. Priority Date: 08/19/2014
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Zhou, Zhi
• Primary Examiner(s): Shaawat, Mussa A
• Assistant Examiner(s): JHA, ABDHESH K
• Application Number:
  US14/479,937
• Publication Number:
  US 20160052505A1
• Time in Patent Office: 1,128 Days
• Field of Search: 701 22, 701110, 701113, 701 36, 701101, 701102, 701103, 701112, 701123, 701 321, 701 337, 701 342, 701 67, 701 70
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/12 Buck converters
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/427 Voltage
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2260/42 by adaptive correction
• CPC Class Codes: B60L 2260/54 Energy consumption estimation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/90 using propulsion power supplied by specific means not covered by groups B60L50/10 - B60L50/50, e.g. by direct conversion of thermal nuclear energy into electricity
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/21 : having the same nominal voltage
• CPC Class Codes: B60L 7/14 : for vehicles propelled by ac motors
• 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 10/26 : for electrical energy, e.g. batteries or capacitors
• 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 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 20/19 : for achieving enhanced acceleration
• CPC Class Codes: B60W 2510/0666 : Engine power
• CPC Class Codes: B60W 2510/085 : Power
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2710/0677 : Engine power
• CPC Class Codes: B60W 2710/086 : Power
• CPC Class Codes: B60W 2710/242 : for electrical energy
• CPC Class Codes: H02J 2310/48 : for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0048 : Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 : Detection of state of health [SOH]
• CPC Class Codes: H02J 7/1423 : with multiple batteries
• 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
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

A vehicle propulsion system includes a plurality of power sources coupled to a final drive of the vehicle propulsion system. A controller is programmed to determine a desired power demand from the power sources and operate a number of the power sources to produce the desired power demand. The controller identifies a least efficient power source of the power sources and controls the least efficient power source to produce power at an optimum operating point of the least efficient power source. The controller also identifies a power output of the least efficient power source corresponding to the optimum operating point, compares the power output of the least efficient power source to the desired power demand, identifies a remaining power demand from the comparison, and controls another power source to produce the remaining power demand.

Claims

1. A vehicle propulsion system comprising:

at least three power sources coupled to a final drive of the vehicle propulsion system; and

a controller configured with a database comprising an efficiency contour map for each power source, the controller programmed to;

determine a power demand sufficient to operate the final drive; and

operate the power sources to produce the power demand, wherein operating the power sources comprises;

identifying a least efficient power source of the power sources;

controlling the least efficient power source to produce power at an operating point relative to the point of maximum efficiency on the efficiency contour map of the least efficient power source;

identifying a power output of the least efficient power source corresponding to the operating point;

comparing the power output of the least efficient power source to the power demand;

identifying a remaining power demand from the comparison; and

controlling at least two remaining power sources of the power sources to produce the remaining power demand by selectively allocating production of power such that at least one remaining power source produces power at an operating point relative to the point of maximum efficiency on the efficiency contour map of the remaining power source.

2. The vehicle propulsion system of claim 1 further comprising:

an internal combustion engine (ICE); and

an electric powertrain comprising;

a DC bus;

at least two electromechanical devices coupled to the DC bus; and

at least one energy storage unit coupled to the DC bus.

3. The vehicle propulsion system of claim 2 wherein the ICE comprises the least efficient power source.

4. The vehicle propulsion system of claim 2 further comprising a contactor positioned to selectively couple an output of the ICE to the DC bus via an alternator.

5. The vehicle propulsion system of claim 4 wherein the controller is further programmed to:

identify an excess power output of the ICE from the comparison; and

close the contactor to charge the energy storage unit using the excess power output.

6. The vehicle propulsion system of claim 5 wherein the controller is further programmed to:

identify parameters of the excess power output;

access a charging degradation model for the energy storage unit; and

iteratively define a charging power allocation to charge the energy storage unit based on the identified parameters and the charging degradation model.

18. The vehicle propulsion system of claim 2 wherein the electromechanical devices comprise the remaining power sources.

7. A method of powering a propulsion system of a hybrid electric vehicle, the method comprising:

determining a power demand sufficient to operate a final drive of the hybrid electric vehicle;

operating at least three power sources coupled to the final drive to produce the power demand, wherein operating the power sources comprises;

identifying a least efficient power source of the power sources;

controlling the least efficient power source to operate relative to a maximum operating efficiency of the least efficient power source based on an efficiency contour map of the least efficient power source stored in a database;

determining a power output of the least efficient power source when operating relative to the maximum operating efficiency;

comparing the power output of the least efficient power source to the power demand;

identifying a remaining power demand from the comparison; and

controlling at least two remaining power sources of the power sources to produce the remaining power demand by selectively allocating production of power such that the at least one remaining power source produces power at an operating point relative to the point of maximum efficiency on an efficiency contour map of the remaining power source stored in the database.

8. The method of claim 7 further comprising;

identifying an excess power output from the comparison; and

charging an energy storage unit of the propulsion system with the excess power output of the least efficient power source.

9. The method of claim 7 further comprising:

identifying an excess power output from the comparison;

querying a state of charge (SOC) of a plurality of energy storage units of the propulsion system;

defining a charging power split between the energy storage units based on the SOC; and

charging at least one of the energy storage units according to the charging power split.

10. The method of claim 9 further comprising defining the charging power split based on charging degradation models for the energy storage units.

11. The method of claim 9 further comprising iteratively defining the charging power split using a multi-objective optimization algorithm.

12. The method of claim 7 further comprising:

controlling an internal combustion engine (ICE) to operate relative to a maximum operating efficiency of the ICE and produce a first portion of the power demand;

controlling a first motor to operate relative to a maximum operating efficiency of the first motor and produce a second portion of the power demand; and

controlling a second motor to produce a remaining portion of the power demand.

13. A control system for a vehicle propulsion system comprising an internal combustion engine (ICE) and an electric powertrain, the electric powertrain comprising at least one energy storage unit and at least two electric motors, the control system comprising a controller configured with a database comprising efficiency contour maps for the ICE and both electric motors, the controller programmed to:

determine a power demand sufficient to operate a final drive of the vehicle propulsion system;

identify an ICE power output corresponding to an operating point relative to the point of maximum efficiency on the efficiency contour map of the ICE;

compare the ICE power output to the power demand; and

if the ICE power output exceeds the power demand, supply a first subportion of the ICE power output to the final drive and supply a second subportion of the ICE power output to the energy storage unit to charge the energy storage unit; and

if the ICE power output does not exceed the power demand, supply the ICE power output to the final drive and supply a remaining power from the electric motors by selectively allocating production of power such that at least one electric motor produces power at an operating point relative to the point of maximum efficiency on the efficiency contour map of the electric motor.

14. The control system of claim 13 wherein the controller is further programmed to iteratively define a charging power allocation for the energy storage unit.

15. The control system of claim 14 wherein the controller is further programmed to:

determine a current state of charge (SOC) of the energy storage unit;

access a charging power degradation model for the energy storage unit; and

define the charging power allocation based on the determined current (SOC) and the charging power degradation model.

16. The control system of claim 13 wherein the controller is further programmed to supply the remaining power using a multi-objective optimization algorithm.

17. The control system of claim 16 wherein the multi-objective optimization algorithm determines an optimal vector of operating coefficients that maximizes an overall operating efficiency of the electric powertrain.