Method for controlling operating speed and torque of electric motor

• US 9,866,164 B2
• Filed: 08/22/2016
• Issued: 01/09/2018
• Est. Priority Date: 03/16/2015
• Status: Active Grant

• Current Assignee: Thunder Power New Energy Vehicle Development Company Limited
• Original Assignee: Thunder Power New Energy Vehicle Development Company Limited
• Inventors: Lai, Sheng-Fu
• Primary Examiner(s): Ro, Bentsu
• Assistant Examiner(s): Dinh, Thai
• Application Number:
  US15/243,061
• Publication Number:
  US 20160355103A1
• Time in Patent Office: 505 Days
• Field of Search: 318139, 318 53, 318 59, 318800, 318801, 318802, 318432, 180233, 180248, 180140, 180197, 180249, 180221
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: B60W 50/0097 Predicting future conditions
• CPC Class Codes: H02P 23/0022 Model reference adaptation, e.g. MRAS or MRAC, useful for control or parameter estimation
• CPC Class Codes: H02P 31/00 Arrangements for regulating or controlling electric motors not provided for in groups H02P1/00 - H02P5/00, H02P7/00 or H02P21/00 - H02P29/00
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: H02P 7/285 controlling armature supply only
• 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 10/72 Electric energy management in electromobility

Abstract

Systems and methods for controlling the operating speed and the torque of an electric motor using an operational model are described. An operational model for the electric motor, including a plot of engine performance parameters, is used for reference, and a most efficient output path, which may pass through an optimal operation region in the operational model, is selected. The most efficient output path may be determined, for example, according to locations of a current output state and a to-be-reached target state in the operational model, enabling the operating state of the motor to reach the target state from the current operating state. By selecting a more efficient output path, the operating efficiency of the motor may be optimized, the life of a battery improved and/or the operating mileage of the vehicle may be increased, without significantly reducing the driving experience.

Claims

1. An electric vehicle motor controller device, comprising:

a central processing unit (CPU); and

a storage device including an operational model stored thereon, the operational model including a plurality of operation positions of an electric motor and an optimal operation region of an electric motor, each operation position indicating at least a value for a speed parameter, wherein the optimal operation region includes one or more of the operation positions, a torque parameter and an operating efficiency parameter of the electric motor;

wherein the CPU is configured to;

receive, from a sensor, a current speed parameter and a current torque parameter of the electric motor;

determine a current operation position of the electric motor in the operational model based on the current speed parameter and the current torque parameter;

determine, from a driving input system, by the processor, a target speed parameter and a target torque parameter corresponding to a target operation position of the electric motor in the operational model;

calculate power requirements for two transition paths connecting the current operation position and the target operation position in the operational model, the two transition paths including a first path consisting of one vector, and a second path consisting of two vectors;

select one of the two transition paths for controlling the electric motor based at least in part on the calculated power requirements;

generate a first instruction to adjust at least one of the current speed parameter and the current torque parameter along the selected path to move the current operation position to an intermediate operation position corresponding to an intermediate speed parameter and an intermediate torque parameter and located in the optimal operation region;

generate a second instruction to adjust the intermediate speed parameter and the intermediate torque parameter to move the intermediate operation position to the target operation position along the selected path; and

execute the first and second instructions to adjust the current operation position to the target operation position.

2. The controller device of claim 1, wherein the processor is further configured to select the intermediate operation position in the optimal operation region as a vertex of the selected path.

3. The controller device of claim 2, wherein:

the intermediate operation position is selected as a position having a shortest linear distance from the optimal operation region to the current operation position.

4. The controller of claim 1, wherein the electric motor is controlled according to the first or second path by changing at least one of the driving voltage and the driving current applied to the electric motor such that the current operation position at any time during the transition to the target operation position is on the selected transition path in the operational model.

5. The controller device of claim 1, wherein the CPU is further configured to:

amend an efficiency parameter on a selected position in the operational model according to a calculated efficiency parameter on the target operation position.

6. The controller device of claim 5, wherein the CPU is further configured to:

amend the efficiency parameter on a selected position in the operational model according to the calculated efficiency parameter on the target operation position comprises;

detect the input voltage and current of the motor at the target operation position;

calculate the actual operating efficiency of the motor at the target operation position according to the torque and the speed of the motor at the target operation position and the detected input voltage and current at the target operation position;

calculate a correction coefficient according to the operating efficiency corresponding to the target operation position in the operational model and the calculated actual operation efficiency of the motor at the target operation position;

select at least one position to be corrected close to the target operation position;

calculate the distance between the target operation position and the position to be corrected;

calculate a correction quantity according to the calculated correction coefficient calculated and the calculated distance; and

correct the position of the position to be corrected in the operational model according to the correction quantity.

7. A method for implementing an electric vehicle motor controller device, the method being implemented by a central processing unit (CPU), the method comprising:

detecting, by a sensor, a current speed parameter and a current torque parameter of the electric motor;

determining, by an operational model which includes a plurality of operation positions of the electric motor and an optimal operation region of an electric motor, each operation position indicating at least a value for a speed parameter, wherein the optimal operation region includes one or more of the operation positions, a torque parameter, an operating efficiency parameter of the electric motor, and a current operation position of the electric motor in the operational model based on the current speed parameter and the current torque parameter;

determining, from a driving input system, by the CPU, a target speed parameter and a target torque parameter corresponding to a target operation position of the electric motor in the operational model;

calculating power requirements for two transition paths connecting the current operation position and the target operation position in the operational model, the two transition paths including a first path consisting of one vector, and a second path consisting of two vectors;

selecting one of the two transition paths for controlling the electric motor based at least in part on the calculated power requirements;

generating a first instruction to adjust at least one of the current speed parameter and the current torque parameter along the selected path to move the current operation position to an intermediate operation position corresponding to an intermediate speed parameter and an intermediate torque parameter and located in the optimal operation region;

generating a second instruction to adjust the intermediate speed parameter and the intermediate torque parameter to move the intermediate operation position to the target operation position along the selected path; and

executing the first and second instructions to adjust the current operation position to the target operation position.

8. The method of claim 7, further comprising selecting the intermediate operation position in the optimal operation region as a vertex of the selected path.

9. The method of claim 8, wherein the intermediate operation position is selected as a position having a shortest linear distance from the optimal operation region to the current operation position.

10. The method of claim 7, further comprising controlling the electric motor according to the first or second path by changing at least one of the driving voltage and the driving current applied to the electric motor such that the current operation position at any time during the transition to the target operation position is on the selected transition path in the operational model.

11. The method of claim 7, further comprising amending an efficiency parameter on a selected position in the operational model according to a calculated efficiency parameter on the target operation position.

12. The method of claim 11, further comprising:

amending the efficiency parameter on a selected position in the operational model according to the calculated efficiency parameter on the target operation position comprises;

detecting the input voltage and current of the motor at the target operation position;

calculating the actual operating efficiency of the motor at the target operation position according to the torque and the speed of the motor at the target operation position and the detected input voltage and current at the target operation position;

calculating a correction coefficient according to the operating efficiency corresponding to the target operation position in the operational model and the calculated actual operation efficiency of the motor at the target operation position;

selecting at least one position to be corrected close to the target operation position;

calculating the distance between the target operation position and the position to be corrected;

calculating a correction quantity according to the calculated correction coefficient calculated and the calculated distance; and

correcting the position of the position to be corrected in the operational model according to the correction quantity.

13. An electric vehicle comprising:

an electric motor;

a motor controller device in communication with the electric motor;

a central processing unit (CPU) in communication with the motor controller; and

a storage device including an operational model stored thereon, the operational model including a plurality of operation positions of the electric motor and an optimal operation region of an electric motor, each operation position indicating at least a value for a speed parameter, wherein the optimal operation region includes one or more of the operation positions, a torque parameter and an operating efficiency parameter of the electric motor;

wherein the CPU is configured to;

detect, by a sensor, a current speed parameter and a current torque parameter of the electric motor;

determine a current operation position of the electric motor in the operational model based on the current speed parameter and the current torque parameter;

determine, from a driving input system, by the CPU, a target speed parameter and a target torque parameter corresponding to a target operation position of the electric motor in the operational model;

calculate power requirements for two transition paths connecting the current operation position and the target operation position in the operational model, the two transition paths including a first path consisting of one vector, and a second path consisting of two vectors;

select one of the two transition paths for controlling the electric motor based at least in part on the calculated power requirements;

generate a first instruction to adjust at least one of the current speed parameter and the current torque parameter along the selected path to move the current operation position to an intermediate operation position corresponding to an intermediate speed parameter and an intermediate torque parameter and located in the optimal operation region;

generate a second instruction to adjust the intermediate speed parameter and the intermediate torque parameter to move the intermediate operation position to the target operation position along the selected path; and

execute the first and second instructions to adjust the current operation position to the target operation position.

14. The electric vehicle of claim 13, wherein the CPU is further configured to select the intermediate operation position in the optimal operation region as a vertex of the selected path.

15. The electric vehicle of claim 14, wherein:

the intermediate operation position is selected as a position having a shortest linear distance from the optimal operation region to the current operation position.

16. The electric vehicle of claim 13, wherein the electric motor is controlled according to the first or second path by changing at least one of the driving voltage and the driving current applied to the electric motor such that the current operation position at any time during the transition to the target operation position is on the selected transition path in the operational model.

17. The electric vehicle of claim 13, wherein the CPU is further configured to:

amend an efficiency parameter on a selected position in the operational model according to a calculated efficiency parameter on the target operation position.

18. The electric vehicle of claim 17, the CPU is further configured to:

amend the efficiency parameter on a selected position in the operational model according to the calculated efficiency parameter on the target operation position comprises;

detect the input voltage and current of the motor at the target operation position;

calculate the actual operating efficiency of the motor at the target operation position according to the torque and the speed of the motor at the target operation position and the detected input voltage and current at the target operation position;

calculate a correction coefficient according to the operating efficiency corresponding to the target operation position in the operational model and the calculated actual operation efficiency of the motor at the target operation position;

select at least one position to be corrected close to the target operation position;

calculate the distance between the target operation position and the position to be corrected;

calculate a correction quantity according to the calculated correction coefficient calculated and the calculated distance; and

correct the position of the position to be corrected in the operational model according to the correction quantity.