Control apparatus and method for operating a switched reluctance motor
First Claim
1. 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.
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Accused Products
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.
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Citations
26 Claims
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1. A method of operating a switched reluctance machine having stator phase windings and a rotor comprising:
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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. - View Dependent Claims (2)
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3. A method of operating a switched reluctance machine having stator phase windings and a rotor comprising:
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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; said controlling step including deriving a control signal from the error signal, said control signal being a function or the error signal and its integral. - View Dependent Claims (4, 5)
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6. A method of operating a switched reluctance machine having stator phase windings and a rotor comprising:
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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. - View Dependent Claims (7)
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8. A method of operating a switched reluctance machine having stator phase windings and a rotor comprising:
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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 limiting 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; limiting the energizing current to the current limiting value to correct the rotor position; and 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. - View Dependent Claims (9, 10, 11)
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12. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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. - View Dependent Claims (13, 14)
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15. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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; said controlling means including 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 with 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.
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16. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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means for cylindrically 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; said controlling means including means responsive to the error signal for increasing the energization current in responsive to an error signal representative of an increased load at a first rate and for decreasing the energization current in response to an error signal representative of a decreased load at a second rate, the first rate being greater than the second rate.
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17. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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means for cylindrically 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; said controlling means including 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. - View Dependent Claims (18)
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19. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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; and 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.
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20. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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. - View Dependent Claims (24)
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21. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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 positon; said current limiting value generating means including 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. - View Dependent Claims (22, 23)
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25. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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; said current limiting value generating means including 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.
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26. Control apparatus for a switched reluctance machine having stator phase windings and a rotor comprising:
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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 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; and 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.
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Specification