System and method for power management during regeneration mode in hybrid electric vehicles

Patent metadata

Field	Value
Publication number	US-9517698-B2
Application number	US-201615071521-A
Country	US
Kind code	B2
Filing date	Mar 16, 2016
Priority date	Mar 14, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A system and method for recovering the optimum power level during regenerative mode is disclosed. Equations for determining the optimum regenerative power level receivable by an energy storage system, for example for any given deceleration event, are derived and disclosed. The equations consider various losses such as the efficiency of the electric motor generator in the generator mode, wind resistance, rolling resistance, transmission losses, engine losses, and losses in the energy storage system. Also disclosed is at least one embodiment of a procedure for controlling a hybrid drive system to achieve the optimum energy recovery.

First claim

What is claimed is:

1. A method of controlling regenerative braking in a hybrid electric vehicle, comprising:
calculating a predicted vehicle energy loss for a vehicle using a vehicle controller, wherein the vehicle has an electric motor generator and an energy storage system, and wherein the electric motor generator is electrically connected to the energy storage system;
calculating an expected electric motor operating efficiency using the vehicle controller;
calculating a predicted electrical power to supply to the energy storage system using the vehicle controller and the predicted vehicle energy loss; and
generating a regenerative braking power using the electric motor generator operating as a generator, wherein the regenerative braking power is less than or equal to the predicted electrical power to supply to the energy storage system.

2. The method of claim 1 , further comprising detecting a deceleration state of the vehicle.

3. The method of claim 2 , wherein the act of detecting a deceleration state includes detecting a torque provided from a transmission to the electric motor generator, wherein the electric motor generator is coupled to the transmission.

4. The method of claim 1 , wherein the predicted vehicle energy loss includes losses caused by an expected change in vehicle kinetic energy.

5. The method of claim 1 , wherein the predicted electrical power to supply to the energy storage system includes a predicted electrical power loss resulting from an expected transfer of the predicted electrical power to the energy storage system.

6. The method of claim 1 , wherein the act of calculating the predicted vehicle energy loss includes calculating an engine energy loss.

7. The method of claim 6 , wherein the act of calculating the engine energy loss includes calculating an engine compression force loss.

8. The method of claim 6 , wherein the act of calculating the engine energy loss includes calculating an engine frictional force loss.

9. The method of claim 1 , wherein the act of calculating the predicted vehicle energy loss includes calculating a wind resistance loss, wherein the wind resistance loss is calculated by the vehicle controller using a vehicle velocity and a vehicle aerodynamic coefficient.

10. The method of claim 1 , wherein the act of calculating the predicted vehicle energy loss includes calculating a rolling resistance loss, wherein the rolling resistance loss is calculated by the vehicle controller using a vehicle mass, a vehicle velocity, and a vehicle rolling resistance coefficient.

11. The method of claim 1 , wherein the act of calculating the predicted vehicle energy loss includes calculating a vehicle transmission loss.

12. The method of claim 11 , wherein the vehicle transmission loss is calculated using a transmission inertia loss and a transmission friction loss.

13. The method of claim 1 , wherein the act of calculating the predicted vehicle energy loss includes calculating an accessory loss.

14. The method of claim 1 , wherein the act of calculating the expected electric motor operating efficiency includes accessing a previous vehicle activity stored in a memory in the vehicle controller and calculating the expected electric motor operating efficiency based on the previous vehicle activity.

15. The method of claim 1 , wherein the act of calculating the expected electric motor operating efficiency is calculated using an electric motor speed and an electric motor torque.

16. The method of claim 5 wherein the predicted electrical power loss can be calculated by the equation:

P
heat

=

R
ESS

⁡

(

P
ESS

V
ESS

)

2

wherein:
P heat is the predicted electrical power loss,
R ESS is a resistance of the energy storage system,
P ESS is the predicted electrical power to supply to the energy storage system, and
V ESS is a voltage supplied to the energy storage system.

17. The method of claim 1 , wherein the predicted electrical power to supply to the energy storage system can be calculated by the equation:

P
ESS

=

efficiency
*

P
Loss

⁡

[

-
1

+

1
+

V
regen
2

efficiency
*

P
Loss

*

R
ESS

]

wherein:
P ESS is the predicted electrical power to supply to the energy storage system,
efficiency is the expected electrical motor operating efficiency,
P Loss is a power loss resulting from a predicted vehicle kinetic energy change,
R ESS is a resistance of the energy storage system, and
V regen is a voltage supplied to the energy storage system from the electric motor generator operating in the generator mode.

18. The method of claim 1 , wherein the energy storage system includes one or more battery cells.

19. The method of claim 2 , wherein the act of detecting a deceleration event includes detecting a zero input signal on a brake pedal, and a zero input signal on an accelerator pedal.

20. A method of calculating regenerative braking power, comprising:
calculating a predicted vehicle energy loss using a vehicle controller in a vehicle having a hybrid system that includes an electric motor generator, an internal combustion engine, and an energy storage system, the vehicle controller calculating the predicted vehicle energy loss using a current rate of deceleration of the vehicle;
calculating a predicted electrical power supplied to the energy storage system using the vehicle controller, the vehicle controller calculating the predicted electrical power using the predicted vehicle energy loss;
calculating a pr

Assignees

• Allison Transm Inc

Inventors

• Runde Jeffrey K
• West Stephen T

Classifications

• B60W20/11

  using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance {(utilising navigation and traffic information in the control strategy B60W20/12)} · CPC title

• B60W40/1005

  Driving resistance · CPC title

• B60W40/12

  related to parameters of the vehicle itself {, e.g. tyre models} · CPC title

• B60W10/26

  for electrical energy, e.g. batteries or capacitors · CPC title

• B60W10/08

  including control of electric propulsion units, e.g. motors or generators · CPC title