VEHICLE PROPULSION SYSTEM HAVING AN ENERGY STORAGE SYSTEM AND OPTIMIZED METHOD OF CONTROLLING OPERATION THEREOF

• US 20160052505A1
• Filed: 09/08/2014
• Published: 02/25/2016
• Est. Priority Date: 08/19/2014
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Zhou, Zhi
• Granted Patent: US 9,783,185 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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:

a plurality of power sources coupled to a final drive of the vehicle propulsion system; and

a controller programmed to;

determine a desired power demand from the plurality of power sources; and

operate a number of the plurality of power sources to produce the desired power demand, wherein operating the number of the plurality of power sources comprises;

identifying a least efficient power source of the plurality of power sources;

controlling the least efficient power source to produce power at an optimum operating point of the least efficient power source;

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

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

identifying a remaining power demand from the comparison; and

controlling another power source of the plurality of power sources to produce the remaining power demand.

2. The vehicle propulsion system of claim 1 wherein the controller is further programmed to operate less than all of the plurality of power sources to produce the desired power demand.

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

an internal combustion engine (ICE);

an electric powertrain comprising;

a DC bus;

at least one electromechanical device coupled to the DC bus; and

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

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

5. The vehicle propulsion system of claim 3 further comprising a contactor positioned to selectively couple an output of the ICE to the DC bus via an alternator.

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

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

close the contactor to charge at least one energy storage unit of the electric powertrain using the excess power output.

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

identify parameters of the excess power output;

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

iteratively define a charging power allocation to recharge the at least one energy storage unit based on the identified parameters and the charging degradation model.

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

determining a power demand of the hybrid electric vehicle;

identifying operating efficiencies of a plurality of power sources coupled to a final drive of the hybrid electric vehicle;

identifying a least efficient power source of the plurality of power sources;

controlling the least efficient power source to operate at a maximum operating efficiency of the least efficient power source;

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

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

controlling another power source of the plurality of power sources to output power to the final drive if the power output of the least efficient power source is less than the total power demand.

9. The method of claim 8 further comprising recharging an energy storage unit of the propulsion system with an excess power output of the least efficient power source if the power output of the least efficient power source is greater than the total power demand.

10. The method of claim 9 further comprising:

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

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

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

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

12. The method of claim 10 further comprising iteratively defining the charging power split using a multi-objective optimization algorithm.

13. The method of claim 8 further comprising:

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

controlling a first motor to produce a second portion of the total power demand; and

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

14. A control system for a vehicle propulsion system comprising an internal combustion engine (ICE) and an electric powertrain, the control system comprising a controller programmed to:

determine a desired power demand from the vehicle propulsion system;

identify an ICE power output corresponding to an optimum operating point of the ICE;

compare the ICE power output to the desired power demand; and

if the ICE power output exceeds the desired power demand, supply a first subportion of the ICE power output to a final drive of the vehicle propulsion system and supply a second subportion of the ICE power output to at least one energy storage unit of the electric powertrain to recharge the at least one energy storage unit; and

if the ICE power output does not exceed the desired power demand, supply the ICE power output to the final drive.

15. The control system of claim 14 wherein the controller is further programmed to iteratively define a charging power allocation for a plurality of energy storage units of the electric powertrain, wherein the charging power allocation allocates the second subportion of the ICE power output to at least one energy storage unit of a plurality of energy storage units of the electric powertrain.

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

determine a current state of charge of the plurality of energy storage units;

access charging power degradation models for the plurality of energy storage units; and

define the charging power allocation based on the determined current state of charge and the charging power degradation models.

17. The control system of claim 14 wherein the controller is further programmed to control the electric powertrain to supply a remaining portion of the desired power demand to the final drive if the ICE power output does not exceed the desired power demand.

18. The control system of claim 17 wherein the controller is further programmed to define a propulsion power split between a plurality of electromechanical devices of the electric powertrain, wherein the propulsion power split allocates generation of the remaining portion of the desired power demand between the plurality of electromechanical devices.

19. The control system of claim 18 wherein the controller is further programmed to:

access efficiency contour maps for the plurality of electromechanical devices of the electric powertrain; and

define the propulsion power split based on the efficiency contour maps.

20. The control system of claim 18 wherein the controller is further programmed to define the propulsion power split using a multi-objective optimization algorithm.

21. The control system of claim 20 wherein the multi-objective optimization algorithm determines an optimal vector of operating coefficients that maximizes an overall operating efficiency of the electric powertrain.