Powertrain with AC brushless starter and sensor/sensorless control method

• US 10,473,081 B1
• Filed: 04/24/2018
• Issued: 11/12/2019
• Est. Priority Date: 04/24/2018
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Hao, Lei, Gopalakrishnan, Suresh, Namuduri, Chandra S.
• Primary Examiner(s): Huynh, Hai H
• Application Number:
  US15/961,094
• Publication Number:
  US 20190323469A1
• Time in Patent Office: 567 Days
• Field of Search: 1231793, 1231794, 12317925, 701113, 7311458, 7311459
• CPC Class Codes: F02N 11/08 Circuits or control means specially adapted for starting of engines
• CPC Class Codes: F02N 15/06 the toothed gears being moved by axial displacement
• CPC Class Codes: F02N 2011/0896 Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: F02N 2200/04 said parameters being related to the starter motor
• CPC Class Codes: F02N 2200/041 Starter speed
• CPC Class Codes: F02N 2300/102 Control of the starter motor speed; Control of the engine speed during cranking
• CPC Class Codes: F02N 2300/104 Control of the starter motor torque
• 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 6/16 Circuit arrangements for detecting position
• CPC Class Codes: H02P 6/182 using back-emf in windings
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

An electric starter system includes a brushless alternating current (AC) starter motor selectively coupled to an engine and having a rotor with a rotor position. A position sensor generates measured position signals indicative of rotor position. A controller is in communication with the sensor. The controller has sensorless logic, e.g., a BEMF, inductance, or high-frequency signal injection method, for generating an estimated rotor position. The controller executes a method in which, below a threshold speed of the starter motor, the controller calibrates the sensorless logic using the measured position signals and controls a torque operation of the starter motor using the measured position signals. Above the threshold speed, the torque operation is controlled solely using the estimated rotor position. A powertrain includes the engine, a transmission, a drive shaft, and a load, along with the electric starter system.

Claims

1. An electric starter system for use with an internal combustion engine and an alternating current (AC) voltage bus, the electric starter system comprising:

a brushless starter motor electrically connected to the AC voltage bus and selectively connectable to the engine in response to a requested engine start event, the brushless starter motor having a rotor with a rotor position;

a position sensor positioned with respect to the rotor that is configured to generate measured position signals indicative of the rotor position; and

a controller in communication with the position sensor and programmed with sensorless logic configured to generate an estimated rotor position;

wherein the controller is configured, below a threshold speed of the brushless starter motor, to;

calibrate the sensorless logic using the measured position signals; and

control a torque operation of the starter motor during the requested engine start event using the measured position signals; and

wherein the controller is configured to control the torque operation of the brushless starter motor above the threshold speed solely using the estimated rotor position.

2. The electric starter system of claim 1, wherein the measured position signals form a pulse train having rising and falling edges, and the controller is configured to determine the angular position of the rotor by detecting the rising and falling edges of the pulse train and using a time between the rising and falling edges.

3. The electric starter system of claim 2, wherein the position sensor includes a Hall-effect sensor.

4. The electric starter system of claim 2, wherein the position sensor includes an inductive sensor.

5. The electric starter system of claim 2, wherein the position sensor includes a reluctance sensor.

6. The electric starter system of claim 1, wherein the sensorless logic includes a back-electromotive force (BEMF) estimation technique.

7. The electric starter system of claim 1, wherein the sensorless logic is an inductance-based estimation technique.

8. The electric starter system of claim 1, wherein the sensorless logic is a high-frequency signal injection-based estimation technique.

9. A hybrid sensor/sensorless control method for use with a system having an alternating current (AC) brushless starter motor selectively connectable to an internal combustion engine, the brushless starter motor having a rotor with a rotor position, a position sensor positioned with respect to the rotor, and a controller in communication with the position sensor, the method comprising:

below a threshold speed of the starter motor;

generating measured angular position signals using the position sensor, the measured angular position signals being indicative of the rotor position of the brushless starter motor;

calibrating sensorless logic of the controller using the measured angular position signals; and

controlling a torque operation the brushless starter motor below the threshold speed using the measured angular position signals; and

above the threshold speed;

generating an estimated rotor position using the sensorless logic; and

controlling the torque operation of the brushless starter motor solely using the estimated rotor position.

10. The method of claim 9, wherein the measured angular position signals form a pulse train having rising and falling edges, the method further comprising:

detecting the rising and falling edges via the controller; and

determining the position and a speed of the rotor using a time between the rising and falling edges.

11. The method of claim 9, wherein the position sensor includes a Hall-effect sensor.

12. The method of claim 9, wherein the position sensor includes an inductive sensor.

13. The method of claim 9, wherein the position sensor includes a reluctance sensor.

14. The method of claim 9, wherein generating an estimated rotor position using the sensorless logic includes using a back-electromotive force (BEMF) estimation technique.

15. The method of claim 9, wherein generating an estimated rotor position using the sensorless logic includes using an inductance-based estimation technique.

16. The method of claim 9, wherein generating an estimated rotor position using the sensorless logic includes using a high-frequency signal injection-based estimation technique.

17. The method of claim 9, further including a transmission coupled to the engine, a drive axle coupled to the transmission, and a load coupled to the drive axle, the method further comprising:

transmitting torque from the engine to the load via the transmission and the drive axle.

18. The method of claim 17, wherein transmitting torque from the engine to the load includes transmitting the torque to a set of drive wheels of a motor vehicle.

19. A powertrain comprising:

an internal combustion engine;

a transmission connected to the engine;

a drive axle connected to the transmission;

a load connected to the drive axle; and

an electric starter system comprising;

a brushless starter motor electrically connected to an alternating current (AC) voltage bus, the brushless starter motor being selectively connectable to the engine in response to a requested engine start event, the brushless starter motor having a rotor with a rotor position;

a position sensor positioned with respect to the rotor that is configured to generate measured position signals indicative of the rotor position; and

a controller in communication with the position sensor and programmed with sensorless logic configured to generate an estimated rotor position;

wherein the controller is configured, below a threshold speed of the brushless starter motor, to;

calibrate the sensorless logic using the measured position signals; and

control a torque operation of the brushless starter motor during the requested engine start event using the measured position signals; and

wherein the controller is configured to control the torque operation of the brushless starter motor above the threshold speed solely using the estimated rotor position.

20. The powertrain of claim 19, wherein the powertrain is part of a motor vehicle, and wherein the load is a set of road wheels of the motor vehicle.