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US6396237B2
Expired / Lapsed
US
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Position detection of switched reluctance machines
Assignee: Nidec SR Drives Ltd
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Filing: 2001-03-27
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Granted: 2002-05-28
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Expires: 2021-03-27
Abstract
Abstract A polyphase switched reluctance machine is controlled by a control system using sensorless position detection. The controller is robust and reliable and operates over the entire current chopping range of the machine. Diagnostic pulses of predetermined flux-linkage are injected into a phase, whether or not it has residual current flowing.
Inventors
- 👤 Peter Richard Mayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:43
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14; H02P6/16; H02P6/18; H02P6/185; H02P25/00; H02P25/02; H02P25/08; H02P25/086; H02P25/089
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
132 words
A method of determining rotor position in a switched reluctance machine comprising a rotor, a stator and at least one phase winding, the method comprising: measuring one of main current and flux-linkage in the phase winding during an inactive period in which the phase is not energized; injecting a diagnostic pulse having a predetermined maximum value of current or flux-linkage into the inactive phase winding; measuring total current or flux-linkage in the phase at the end of the pulse; producing a value for the current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; and deriving rotor position from a correlation of the current or flux-linkage with rotor angle for a value of the other of current and flux-linkage.
Claim 2
Independent Claim
132 words
A method of determining rotor position in a switched reluctance machine comprising a rotor, a stator and at least one phase winding, the method comprising: measuring one of main current and flux-linkage in the phase winding during an inactive period in which the phase is not energized; injecting a diagnostic pulse having a predetermined maximum value of current or flux-linkage into the inactive phase winding; measuring total current or flux-linkage in the phase at the end of the pulse; producing a value for the current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; and deriving rotor position from a correlation of the current or flux-linkage with rotor angle for a value of the other of current and flux-linkage.
Claim 3
Dependent Claim
34 words
A method as claimed in claim 1 in which the diagnostic pulse is injected when phase current has fallen below a predetermined value to a range in which inductance is substantially independent of current.
Claim 4
Dependent Claim
25 words
A method as claimed in claim 1 in which the pulse is of predetermined flux-linkage and is measured by integrating voltage across the phase winding.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 1 in which the diagnostic pulse is injected by switching; a supply voltage across the phase winding.
Claim 6
Dependent Claim
33 words
A method as claimed in claim 1 including: comparing the derived rotor position with a predicted value of rotor position; and selecting between the derived and predicted values as the determined rotor position.
Claim 7
Dependent Claim
30 words
A method as claimed in claim 5 including selecting the predicted value of rotor position if the derived rotor position differs from the predicted rotor position by a predetermined amount.
Claim 8
Dependent Claim
41 words
A method as claimed in claim 5 including modifying control of the machine if the error between the derived rotor position and the predicted rotor position differs by a second predetermined amount for a number of successive determinations of rotor position.
Claim 9
Dependent Claim
37 words
A method as claimed in claim 1 including comparing measured main current with a predetermined value corresponding to a region of linear inductance and proceeding with the method if the main current is below the predetermined value.
Claim 10
Dependent Claim
22 words
A computer program element comprising computer program code means to make a computer execute the method as claimed in claim 1 .
Claim 11
Independent Claim
198 words
A method of determining rotor position in a switched reluctance machine comprising a rotor, a stator and at least one phase winding, the method comprising: measuring one of main current and flux-linkage in the phase winding during an inactive period in which the phase is not energized; injecting a diagnostic pulse having a predetermined maximum value of current or flux-linkage into the inactive phase winding, the diagnostic pulse being injected when phase current has fallen below a predetermined value to a range in which inductance is substantially independent of current, the diagnostic pulse being of predetermined flux-linkage and being measured by integrating voltage across the phase winding; measuring total current or flux-linkage in the phase at the end of the pulse; producing a value for the current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; deriving rotor position from a correlation of the current or flux-linkage with rotor angle for a value of the other of current and flux-linkage; comparing, the derived rotor position with a predicted value of rotor position; and selecting between the derived and predicted values as the determined rotor position.
Claim 12
Independent Claim
198 words
A method of determining rotor position in a switched reluctance machine comprising a rotor, a stator and at least one phase winding, the method comprising: measuring one of main current and flux-linkage in the phase winding during an inactive period in which the phase is not energized; injecting a diagnostic pulse having a predetermined maximum value of current or flux-linkage into the inactive phase winding, the diagnostic pulse being injected when phase current has fallen below a predetermined value to a range in which inductance is substantially independent of current, the diagnostic pulse being of predetermined flux-linkage and being measured by integrating voltage across the phase winding; measuring total current or flux-linkage in the phase at the end of the pulse; producing a value for the current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; deriving rotor position from a correlation of the current or flux-linkage with rotor angle for a value of the other of current and flux-linkage; comparing, the derived rotor position with a predicted value of rotor position; and selecting between the derived and predicted values as the determined rotor position.
Claim 13
Dependent Claim
175 words
A rotor position detector for a switched reluctance drive comprising a machine having a rotor, a stator, at least one phase winding and switch means actuatable for energizing the at least one phase winding, the rotor position detector comprising: means for measuring one of main current and flux-linkage in the phase; means for causing the means for measuring to measure main current or flux-linkage during an inactive period in which the phase is not energized; means for injecting a diagnostic pulse, having a predetermined value of the one of current and flux-linkage, into the inactive phase; means for causing the means for measuring to measure the total current or flux-linkage in the phase at the end of the pulse; means for producing a value of current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; and means for deriving rotor position from a correlation of current or flux-linkage with rotor angle for a value of the other of the current and flux-linkage.
Claim 14
Dependent Claim
175 words
A rotor position detector for a switched reluctance drive comprising a machine having a rotor, a stator, at least one phase winding and switch means actuatable for energizing the at least one phase winding, the rotor position detector comprising: means for measuring one of main current and flux-linkage in the phase; means for causing the means for measuring to measure main current or flux-linkage during an inactive period in which the phase is not energized; means for injecting a diagnostic pulse, having a predetermined value of the one of current and flux-linkage, into the inactive phase; means for causing the means for measuring to measure the total current or flux-linkage in the phase at the end of the pulse; means for producing a value of current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage; and means for deriving rotor position from a correlation of current or flux-linkage with rotor angle for a value of the other of the current and flux-linkage.
Claim 15
Dependent Claim
46 words
A detector as claimed in claim 11 including means for monitoring phase current and for causing the means for injecting to inject the diagnostic pulse when the phase current has fallen below a predetermined value to a range in which inductance is substantially independent of current.
Claim 16
Dependent Claim
31 words
A detector as claimed in claim 11 in which the pulse is of predetermined flux-linkage, the detector including an integrator arranged to integrate voltage across the phase to measure the flux-linkage.
Claim 17
Dependent Claim
22 words
A detector as claimed in claim 11 in which the means for injecting comprises the switch means of the switched reluctance drive.
Claim 18
Dependent Claim
32 words
A detector as claimed in claim 11 including means for comparing the derived rotor position with a predicted value of rotor position and means for selecting between the derived and predicted values.
Claim 19
Dependent Claim
36 words
A detector as claimed in claim 15 in which the means for selecting is operable to select between the derived and predicted values if the derived value differs from the predicted value by a predetermined amount.
Claim 20
Dependent Claim
45 words
A detector as claimed in claim 15 in which the means for selecting is operable to select between the derived and predicted values if the derived value differs from the predicted value by a predetermined amount for a number of successive derivations of rotor position.
Claim 21
Dependent Claim
149 words
A rotor position detector for a switched reluctance drive comprising a machine having a rotor, a stator, at least one phase winding and at least one switch actuatable for energizing the at least one phase winding, the rotor position detector measuring one of main current and flux-linkage in the phase during an inactive period in which the phase is not energized, injecting a diagnostic pulse into the inactive phase, the pulse having a predetermined value of the one of current and flux-linkage, measuring the total current or flux-linkage in the phase at the end of the pulse, producing a value of current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage, and deriving rotor position from a correlation of current or flux-linkage with rotor angle for a value of the other of the current and flux-linkage.
Claim 22
Dependent Claim
149 words
A rotor position detector for a switched reluctance drive comprising a machine having a rotor, a stator, at least one phase winding and at least one switch actuatable for energizing the at least one phase winding, the rotor position detector measuring one of main current and flux-linkage in the phase during an inactive period in which the phase is not energized, injecting a diagnostic pulse into the inactive phase, the pulse having a predetermined value of the one of current and flux-linkage, measuring the total current or flux-linkage in the phase at the end of the pulse, producing a value of current or flux-linkage due to injection of the diagnostic pulse from the difference between the total current and the main current or flux-linkage, and deriving rotor position from a correlation of current or flux-linkage with rotor angle for a value of the other of the current and flux-linkage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-05-27 | 2005-11-26 | 2006-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-05-27 | 2009-11-26 | 2010-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-05-27 | 2013-11-26 | 2014-05-28 | $7700.00 | Window Closed / Lapsed |