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

• US 20160052417A1
• Filed: 08/19/2014
• 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, King, Robert Dean, Zhou, Jian, Sun, Fengcheng, Li, Zhihao
• Granted Patent: US 9,878,632 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 11/005 using capacitors
• CPC Class Codes: B60L 11/1853 by battery splitting
• 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 50/40 using propulsion power supplied by capacitors
• 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: 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 control system for controlling the supply of power from an energy storage system to a DC bus of a vehicle propulsion system is disclosed herein. The control system includes a controller programmed to monitor real-time operating parameters of a plurality of energy storage units of the energy storage system, access degradation models for the plurality of energy storage units, and optimize usage of the plurality of energy storage units during real-time operation of the vehicle propulsion system based on the degradation models.

Claims

1. A control system for controlling the supply of power from an energy storage system to a DC bus of a vehicle propulsion system, the control system comprising a controller programmed to:

monitor real-time operating parameters of a plurality of energy storage units of the energy storage system;

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

optimize usage of the plurality of energy storage units during real-time operation of the vehicle propulsion system based on the degradation models.

2. The control system of claim 1 wherein the controller is programmed to:

determine a future power demand of the vehicle propulsion system based on at least one of a user input and a predetermined vehicle duty cycle; and

optimize usage of the plurality of energy storage units during real-time operation of the vehicle propulsion system based on the future power demand and the degradation models.

3. The control system of claim 2 wherein the controller, in being programmed to optimize usage of the plurality of energy storage units, is programmed to:

define a power split between the plurality of energy storage units, the power split comprising an allocation of the future power demand of the vehicle propulsion system between the plurality of energy storage units; and

iteratively adjust the power split in real-time to maximize at least one of a performance of the vehicle propulsion system and an operating life of the plurality of energy storage units.

4. The control system of claim 3 wherein the controller, in being programmed to optimize usage of the plurality of energy storage units, is programmed to run a power split algorithm that defines a power split coefficient for each energy storage unit of the plurality of energy storage units.

5. The control system of claim 3 wherein the controller is further programmed to selectively operate a bi-directional DC-DC converter to cause a first energy storage unit of the plurality of energy storage units to supply power to the DC bus in accordance with the adjusted power split, the bi-directional DC-DC converter coupled between the first energy storage unit and the DC bus.

6. The control system of claim 3 wherein the controller is further programmed to:

monitor a real-time state-of-charge (SOC) of the plurality of energy storage units;

monitor a real-time state-of-health (SOH) of the plurality of energy storage units; and

determine a real-time maximum power available of the plurality of energy storage units.

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

determine if operating in accordance with the power split would violate at least one system constraint; and

if operating in accordance with the power split would violate at least one system constraint, modify the power split; and

if operating in accordance with the power split would not violate the at least one system constraint, predict a change in the SOC and a change in the SOH of the plurality of energy storage units resulting from operation at the power split.

8. The control system of claim 7 wherein the controller is further programmed to run a multi-objective optimization algorithm that generates an adjusted power split for the plurality of energy storage units based on the predicted change in the SOC and the predicted change in the SOH.

9. A method for supplying power to a DC bus of a vehicle propulsion system, the method comprising:

monitoring operating parameters of a plurality of energy storage units of an energy storage system at a first time and at a second time;

accessing degradation models for the plurality of energy storage units;

determining a first future power demand of the vehicle propulsion system based on at least one of a first user input and a predetermined vehicle duty cycle;

defining a first power allocation between the plurality of energy storage units based on the first future power demand, the monitored real-time operating parameters at the first time, and the degradation models;

determining a second future power demand of the vehicle propulsion system based on at least one of a second user input and the predetermined vehicle duty cycle; and

defining a second power allocation between the plurality of energy storage units based on the second future power demand, the monitored real-time operating parameters at the second time, and the degradation models, wherein the second power allocation differs from the first power allocation.

10. The method of claim 9 further comprising:

determining a real-time state-of-charge (SOC) and a real-time state-of-health (SOC) of the plurality of energy storage units at the first time; and

defining the first power allocation based on the real-time SOC of the plurality of energy storage units, the real-time SOH of the plurality of energy storage units, and the degradation models for the plurality of energy storage units.

11. The method of claim 9 further comprising:

determining a change in the SOC and a change in the SOH of the plurality of energy storage units resulting from the first power allocation; and

inputting the change in the SOC and the change in the SOH into a system constraint function; and

modifying the first power allocation if the change in the SOC and the change in the SOH violate the system constraint function.

12. The method of claim 9 further comprising defining the first power allocation and the second power allocation using a multi-objective optimization algorithm;

wherein the multi-objective optimization algorithm defines a first set of power split coefficients for the plurality of energy storage units for the first power allocation; and

wherein the multi-objective optimization algorithm defines a second set of power split coefficients for the plurality of energy storage units for the second power allocation.

13. The method of claim 9 further comprising controlling at least one bi-directional DC-DC voltage converter assembly to cause the plurality of energy storage units to supply power to a DC bus in accordance with the first and second power allocations.

14. The method of claim 9 further comprising:

accessing a database having stored thereon a predefined duty cycle for the vehicle propulsion system; and

determining at least one of the first future power demand and the second future power demand from the predefined duty cycle.

15. The method of claim 9 further comprising determining at least one of the first future power demand and the second future power demand from a user input.

16. The method of claim 9 further comprising:

determining if operating the vehicle propulsion system in accordance with the first power allocation violates a system constraint function; and

if the system constraint function is violated, modifying the first power allocation for the energy storage system; and

if the system constraint function is not violated, controlling the least one bi-directional DC-DC voltage converter assembly coupled to the energy storage system to cause the plurality of energy storage units to supply power to the DC bus in accordance with the first power allocation.

17. A vehicle propulsion system comprising:

a first bi-directional converter coupled to a DC bus;

an energy storage system comprising a first energy storage unit and a second energy storage unit, wherein the first energy storage unit is coupled to the first bi-directional converter assembly; and

a controller programmed to;

determine a future power demand of the vehicle propulsion system;

define a plurality of power allocations for the energy storage system based on real-time operating parameters of the first and second energy storage units and degradation models of the first and second energy storage units; and

control the first bi-directional converter to transfer power from the first energy storage device to the DC bus based on respective power allocations of the plurality of power allocations; and

wherein the plurality of power allocations optimize usage of the first and second of energy storage units during real-time operation of the vehicle propulsion system based on the future power demand and the degradation models.

18. The vehicle propulsion system of claim 17 wherein a power allocation of the plurality power allocations allocates a first portion of the power demand to the first energy storage unit and a second portion of the power demand to the second energy storage unit.

19. The vehicle propulsion system of claim 17 wherein the real-time operating parameters comprise a real-time state-of-charge (SOC), a real-time state-of-health (SOH), and a maximum available power of the first and second energy storage units.

20. The vehicle propulsion system of claim 17 wherein the controller is further programmed to define the plurality of power allocations using a multi-objective optimization algorithm that defines power split coefficients for the first and second energy storage units.

21. The vehicle propulsion system of claim 20 wherein the controller is further programmed to:

test a power allocation of the plurality of power allocations to determine if the operating the vehicle propulsion system in accordance with the power allocation violates a system constraint; and

if operating the vehicle propulsion system in accordance with the power allocation violates the system constraint, modify the power allocation; and

if operating the vehicle propulsion system in accordance with the power allocation does not violate the system constraint, optimize the power allocation using the multi-objective optimization algorithm.