Claims
- 1. A sensorless method of controlling the landing velocity of an armature in an electromagnetic actuator, comprising the steps of:providing an electromagnetic actuator having a coil; measuring the inductance of the coil in real-time as the armature moves within the coil; compensating the measured inductance for non-linear permeability and magnetization effects; and providing the measured inductance to a control system for modulating a current delivered to the actuator.
- 2. The method of claim 1, further comprising the step of normalizing the measured inductance at zero gap.
- 3. The method of claim 2, further comprising the steps of:estimating the rate of change of inductance of the coil in real-time as the armature moves within the actuator; compensating the estimated rate of change of inductance for non-linear permeability and magnetization effects; and providing the compensated rate of change of inductance to a control system for modulating a current delivered to the actuator.
- 4. The method of claim 3, wherein the rate of change of inductance is determined without differentiating the inductance signal.
- 5. The method of claim 4, further comprising the step of capturing the B-H magnetization characteristics of the actuator during an armature stroke.
- 6. The method of claim 5, wherein the step of capturing the B-H magnetization characteristics of the actuator during an armature stroke further includes:maintaining the armature in contact with a pole piece; driving a time-varying current through the coil; sampling the voltages associated with a plurality of current levels; computing inductance values associated with each sampled voltage and current level; and computing mu factors for each inductance value.
- 7. The method of claim 5, wherein the inductance corresponds to an armature position estimation and the rate of change of inductance corresponds to an armature velocity estimation.
- 8. The method of claim 5, further comprising the step of measuring the coil resistance of the actuator while the armature is in a rest position against a stator core.
- 9. The method of claim 8, wherein the step of measuring the coil resistance of the actuator while the armature is in a rest position against a stator core further includes:driving the coil with a steady-state current; measuring the coil voltage necessary to maintain the steady-state current through the coil; and dividing the measured voltage by the steady-state current to calculate coil resistance.
- 10. The method of claim 9, wherein the control system is a fuzzy logic control system.
- 11. The method of claim 9, wherein the control system is a full state feedback control system.
- 12. The method of claim 9, wherein the control system is a PID control system.
- 13. The method of claim 9, wherein the electromechanical actuator is operatively attached to a fuel injector.
- 14. The method of claim 13, wherein the fuel injector is a direct injection fuel injector.
- 15. The method of claim 9, wherein the electromechanical actuator is an EVT actuator.
- 16. The method of claim 9, wherein the control system comprises a microprocessor.
- 17. The method of claim 9, wherein the control system comprises a digital logic circuit.
- 18. The method of claim 9, wherein the control system comprises an analog circuit.
- 19. A method of controlling the velocity of an armature in an electromagnetic actuator as the armature moves from a first position towards a second position, the electromagnetic actuator including a coil and a core at the second position, the coil conducting a current and generating a magnetic force to cause the armature to move towards and land at the second position, and a spring structure acting on the armature to bias the armature from the second position, the method comprising the steps of:measuring the inductance of the coil as the armature moves within the actuator; compensating the measured inductance for non-linear permeability and magnetization effects; and providing the measured inductance to a control system for modulating a current delivered to the actuator.
- 20. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 19, further comprising the step of normalizing the measured inductance at zero gap.
- 21. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 20, further comprising the steps of:estimating the rate of change of inductance of the coil as the armature moves within the actuator; compensating the estimated rate of change of inductance for non-linear permeability and magnetization effects; and providing the compensated rate of change of inductance to a control system for modulating a current delivered to the actuator.
- 22. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 21, wherein the rate of change of inductance is determined without differentiating the inductance signal.
- 23. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 22, further comprising the step of capturing the B-H magnetization characteristics of the actuator during an armature stroke.
- 24. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 23, wherein the step of capturing the B-H magnetization characteristics of the actuator during an armature stroke further includes:maintaining the armature in contact with a pole piece; driving a time-varying current through the coil; sampling the voltages associated with a plurality of current levels; computing inductance values associated with each sampled voltage and current level; and computing mu factors for each inductance value.
- 25. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 23, wherein the inductance corresponds to an armature position estimation and the rate of change of inductance corresponds to an armature velocity estimation.
- 26. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 23, further comprising the step of measuring the coil resistance of the actuator while the armature is in a rest position against a stator core.
- 27. The method of controlling velocity of an armature in an electromagnetic actuator according to claim 26, wherein the step of measuring the coil resistance of the actuator while the armature is in a rest position against a stator core further includes:driving the coil with a steady-state current; measuring the coil voltage necessary to maintain the steady-state current through the coil; and dividing the measured voltage by the steady-state current to calculate coil resistance.
- 28. The method of claim 27, wherein the control system is a logic control system.
- 29. The method of claim 27, wherein the control system is a full state feedback control system.
- 30. The method of claim 27, wherein the control system is a PID) control system.
- 31. The method of claim 27, wherein the electromechanical actuator is operatively attached to a fuel injector.
- 32. The method of claim 31, wherein the fuel injector is a direct injection fuel injector.
- 33. The method of claim 27, wherein the electromechanical actuator is an EVT actuator.
- 34. The method of claim 27, wherein the control system comprises a microprocessor.
- 35. The method of claim 27, wherein the control system comprises a digital logic circuit.
- 36. The method of claim 27, wherein the control system comprises an analog circuit.
- 37. An apparatus for controlling velocity of an armature in an electromagnetic actuator as the armature moves from a first position towards a second position, the electromagnetic actuator including a coil and a core at the second position, the coil conducting a current and generating a magnetic force to cause the armature to move towards and land at the second position, and a spring structure acting on the armature to bias the armature from the second position, the apparatus comprising:a means for estimating the rate of change of inductance of the coil as the armature moves within the actuator; a means for compensating the estimated rate of change of inductance for non-linear permeability and magnetization effects; a means for normalizing the measured inductance at zero gap; a means for estimating the rate of change of inductance of the coil in real-time as the armature moves within the actuator; a means for compensating the estimated rate of change of inductance for non-linear permeability and magnetization effects.
Parent Case Info
This application claims the benefit of U.S. Provisional Application No. 60/143,619, filed Jul. 13, 1999, which is hereby incorporated by reference in its entirety.
US Referenced Citations (14)
Foreign Referenced Citations (8)
Number |
Date |
Country |
37 30 523 |
Mar 1989 |
DE |
195 35 211 |
Mar 1997 |
DE |
195 35 211 |
Mar 1997 |
DE |
195 44 207 |
Jun 1997 |
DE |
197 23 563 |
Dec 1998 |
DE |
0 924 589 |
Jun 1999 |
EP |
0 927 817 |
Jul 1999 |
EP |
WO 9838656 |
Sep 1998 |
WO |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/143619 |
Jul 1999 |
US |