EP0276625A2
Expired / Lapsed
EP
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Control apparatus and method for operating a switched reluctance motor
Assignee: Emerson Electric Co
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Filing: 1987-12-17
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Granted: —
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Expires: 2007-12-17
Abstract
Abstract A switched reluctance motor is cyclically energized to operate at a desired speed. The energizing current is sampled at a predetermined time after the beginning of the cycle, the energizing current at that time being a function of rotor position. The sampled current value is compared with a reference to generate an error signal representative of the difference between the rotor position and the desired rotor position at the beginning of the cycle. The energization current is controlled in response to the error signal so as to correct the rotor position during the next cycle in the direction of the desired position. The energizing current is compared with the current limiting value derived from the error signal so that the current limiting value reflects the difference between the actual rotor position and the desired rotor position. The energizing current is limited to the current limiting value to correct the rotor position.
Inventors
- 👤 Ilija Jovan Obradovic
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 20:56
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/08; H02P25/086; H02P25/089; H02P6/00; H02P6/28
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
115 words
A method of operating a switched reluctance machine having stator phase windings and a rotor comprising: cyclically energizing the phase windings to operate the machine at a desired speed; sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; comparing the sampled current value with a reference to generate an error signal representative of the difference between the rotor position and a desired rotor position at the beginning of a cycle; controlling the energization current in response to the error signal so as to correct the rotor position during the next cycle in the direction of the desired position.
Claim 2
Independent Claim
115 words
A method of operating a switched reluctance machine having stator phase windings and a rotor comprising: cyclically energizing the phase windings to operate the machine at a desired speed; sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; comparing the sampled current value with a reference to generate an error signal representative of the difference between the rotor position and a desired rotor position at the beginning of a cycle; controlling the energization current in response to the error signal so as to correct the rotor position during the next cycle in the direction of the desired position.
Claim 3
Dependent Claim
56 words
The method as set forth in claim 1 when the machine has a plurality of phases, each phase having a cycle, said sampling, comparing and controlling steps occuring for each phase so that an error signal generated in the cycle of one phase is at least partially corrected for in the energization of the next phase.
Claim 4
Dependent Claim
19 words
The method as set forth in claim 1 wherein the predetermined time is a function of desired machine speed.
Claim 5
Dependent Claim
19 words
The method as set forth in claim 3 wherein the reference is also a function of desired machine speed.
Claim 6
Dependent Claim
34 words
The method as set forth in claim 1 wherein the controlling step includes deriving a control signal from the error signal, said control signal being a function or the error signal and its integral.
Claim 7
Dependent Claim
34 words
The method as set forth in claim 5 wherein the control signal is the sum of a signal proportional to the error signal and a signal representative of the integral of the error signal.
Claim 8
Dependent Claim
55 words
The method as set forth in claim 6 wherein the signal proportional to the error signal has a greater proportionality factor for positive values of the error signal than for negative values of the error signal, so that energization current is increased faster under increased load conditions than it is decreased under decreased load conditions.
Claim 9
Dependent Claim
18 words
The method as set forth in claim 1 wherein the reference is a function of desired machine speed.
Claim 10
Independent Claim
110 words
A method of operating a switched reluctance machine having stator phase windings and a rotor comprising: cyclically energizing the phase windings to operate the rotor at a desired speed; sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; comparing the energizing current with a current limiting value, said current limitng value being a function of the energizing current sample, so that the current limiting value reflects the difference between the actual rotor position and a desired rotor position; and limiting the energizing current to the current limiting value to correct the rotor position.
Claim 11
Independent Claim
110 words
A method of operating a switched reluctance machine having stator phase windings and a rotor comprising: cyclically energizing the phase windings to operate the rotor at a desired speed; sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; comparing the energizing current with a current limiting value, said current limitng value being a function of the energizing current sample, so that the current limiting value reflects the difference between the actual rotor position and a desired rotor position; and limiting the energizing current to the current limiting value to correct the rotor position.
Claim 12
Dependent Claim
59 words
The method as set forth in claim 9 wherein the machine has a plurality of phases energized in turn, each phase having a cycle, said sampling, comparing and limiting steps occuring for each phase so that the current limiting value resulting from a current sample from one phase is used in limitng the energizing current for the next phase.
Claim 13
Dependent Claim
19 words
The method as set forth in claim 9 wherein the predetermined time is a function of desired machine speed.
Claim 14
Dependent Claim
39 words
The method as set forth in claim 9 including the step of comparing the sampled current value to a reference to obtain an error signal, said current limiting value being a function of the error signal and its integral.
Claim 15
Dependent Claim
18 words
The method as set forth in claim 12 wherein the reference is a function of desired machine speed.
Claim 16
Dependent Claim
35 words
The method as set forth in claim 12 wherein the current limiting value is the sum of a signal proportional to the error signal and a signal representative of the integral of the error signal.
Claim 17
Dependent Claim
55 words
The method as set forth in claim 14 wherein the signal proportional to the error signal has a greater proportionality factor for positive values of the error signal than for negative values of the error signal, so that energization current is increased faster under increased load conditions than it is decreased under decreased load conditions.
Claim 18
Dependent Claim
126 words
Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising: means for cyclically energizing the phase windings to operate the machine at a desired speed; means for sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; means for comparing the sampled current value with a reference to generate an error signal representative of the difference between the rotor position and a desired rotor position at the beginning of a cycle; said energizing means including means for controlling the energization current in response to the error signal so as to correct the rotor position during the next cycle in the direction of the desired position.
Claim 19
Dependent Claim
126 words
Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising: means for cyclically energizing the phase windings to operate the machine at a desired speed; means for sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; means for comparing the sampled current value with a reference to generate an error signal representative of the difference between the rotor position and a desired rotor position at the beginning of a cycle; said energizing means including means for controlling the energization current in response to the error signal so as to correct the rotor position during the next cycle in the direction of the desired position.
Claim 20
Dependent Claim
68 words
The control apparatus as set forth in claim 16 wherein the machine has a plurality of phases, the energizing means including means for cyclically selecting the phase to be energized and controlling the length of time the phase is energized, said sampling means being responsive to the initiation of energization of a phase to sample the current in that phase the predetermined time after the initiation of energization.
Claim 21
Dependent Claim
38 words
The control apparatus as set forth in claim 16 further including means for setting the desired speed of operation of the machine and means responsive to the speed setting means for setting the predetermined time and the reference.
Claim 22
Dependent Claim
70 words
The control apparatus as set forth in claim 16 wherein the controlling means includes means responsive to the error signal for generating a first control signal proportional to the error signal, the first control signal means generating a signal witn a first factor of proportionality for error signals indicative of increased loads and generating a signal with a second, smaller, factor of proportionality for error signals indicative of decreased loads.
Claim 23
Dependent Claim
70 words
The control apparatus as set forth in claim 16 wherein the controlling means includes means responsive to the error signal for increasing the energization current in response to an error signal representative of an increased load at a first rate and for decreasing the energizaion current in respone to an error signal representatiave of a decreased load at a second rate, the first rate being greater than the second rate.
Claim 24
Dependent Claim
39 words
The control apparatus as set forth in claim 16 wherein the controlling means includes means for generating a current limiting value from the error signal, the current limiting value being a function of the error signal and its integral.
Claim 25
Dependent Claim
40 words
The control apparatus as set forth in claim 21 wherein the controlling means further includes means for modulating the energizing current in response to the current limiting value to keep the energizing current no greater than the current limiting value.
Claim 26
Dependent Claim
38 words
The control apparatus as set forth in claim 16 further including means responsive to a sudden increase in load for reducing the rate of the cyclical energization of the phase windings for a relatively short length of time.
Claim 27
Dependent Claim
130 words
Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising: means for cyclically energizing the phase windings to operate the machine at a desired speed; means for sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; means responsive to the energizing current sample for generating a current limiting value which is a function of the energizing current sample so that the current limiting value reflects the difference between the actual rotor position and a desired rotor position; said energizing means including means for comparing the energizing current with the current limiting value and for limiting the energizing current to the current limiting value to correct the rotor position.
Claim 28
Dependent Claim
130 words
Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising: means for cyclically energizing the phase windings to operate the machine at a desired speed; means for sampling the energizing current at a predetermined time after the beginning of a cycle, the energizing current at that time being a function of rotor position; means responsive to the energizing current sample for generating a current limiting value which is a function of the energizing current sample so that the current limiting value reflects the difference between the actual rotor position and a desired rotor position; said energizing means including means for comparing the energizing current with the current limiting value and for limiting the energizing current to the current limiting value to correct the rotor position.
Claim 29
Dependent Claim
46 words
The control apparatus as set forth in claim 24 wherein the current limiting value generating means includes means for comparing the sampled current value to a reference to obtain an error signal, said current limiting value being a function of the error signal and its integral.
Claim 30
Dependent Claim
32 words
The control apparatus as set forth in claim 25 further including means for setting the desired speed of the machine and means responsive to the speed setting means for setting the reference.
Claim 31
Dependent Claim
38 words
The control apparatus as set forth in claim 25 wherein the current limiting value generating means includes means for summing a signal proportional to the error signal and a signal representative of the integral of the error signal.
Claim 32
Dependent Claim
68 words
The control apparatus as set forth in claim 24 wherein the machine has a plurality of phases, the energizing means including means for cyclically selecting the phase to be energized and controlling the length of time the phase is energized, said sampling means being responsive to the initiation of energization of a phase to sample the current in that phase the predetermined time after the initiation of energization.
Claim 33
Dependent Claim
35 words
The control apparatus as set forth in claim 24 further including means for setting the desired speed of operation of the machine and means responsive to the speed setting means for setting the predetermined time.
Claim 34
Dependent Claim
91 words
The control apparatus as set forth in claim 24 wherein the current limiting value generating means includes means for comparing the sampled current value to a reference to obtain an error signal and means responsive to the error signal for increasing the current limiting value in response to an error signal representative of an increased load at a first rate and for decreasing the current limiting value in response to an error signal representative of a decreased load at a second rate, the first rate being greater than the second rate.
Claim 35
Dependent Claim
38 words
The control apparatus as set forth in claim 24 further including means responsive to a sudden increase in load for reducing the rate of the cyclical energization of the phase windings for a relatively short length of time.
References Cited (Backward Citations)
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