US3911339A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for controlling the output condition of a synchronous reluctance motor
Assignee: Western Atlas Inc
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Filing: 1974-10-18
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Granted: 1975-10-07
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Expires: 1994-10-18
Abstract
Abstract A method for controlling the output torque condition of a synchronous reluctance motor. The method includes the steps of establishing the frequency of the stator current at a value equal to that of the existing rotor frequency and concurrently establishing the magnitude and phase displacement of the stator current at values tending to maintain the direct axis flux at a desired level during the production of motor torque. The invention also obtains the speed control of synchronous reluctance motors.
Inventors
- 👤 Charles E Rettig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:12
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/08; H02P25/092; H02P25/0925
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
275 words
A method of producing a desired torque condition in a synchronous reluctance motor, said torque being produced by the interaction of a quadrature axis flux and a direct axis flux, said motor including a stator winding energized by a phase displaceable stator current having a frequency characteristic and a salient pole rotor, the rotary condition of which is definable in tErms of a rotor frequency which is referenced to the stator winding, said method comprising the steps of: a. providing an adjustable stator current for the motor; b. sensing the existing rotor frequency of the rotor; c. establishing the frequency of the stator current responsive to the sensed rotor frequency to a value equal to the value of the existing rotor frequency under all operating conditions of the motor; d. altering the magnitude of the stator current responsive to the sensed rotor frequency to a value prescribed solely as a predetermined function of the desired motor torque condition when the quadrature axis flux appears so that the direct axis flux remains constant relative to the desired motor torque condition regardless of the voltage condition of the synchronous reluctance motor to permit motoring and regenerative operation of the motor; and e. concurrently establishing the phase displacement of the stator current at a predetermined displacement angle prescribed solely as a predetermined function of the desired motor torque condition, f. the concurrent predetermined establishment of the stator current magnitude and phase angle values being such as to tend to fix the direct axis flux of the motor at a desired level while generating a predetermined torque producing quadrature axis flux and the desired torque condition in the motor.
Claim 2
Independent Claim
275 words
A method of producing a desired torque condition in a synchronous reluctance motor, said torque being produced by the interaction of a quadrature axis flux and a direct axis flux, said motor including a stator winding energized by a phase displaceable stator current having a frequency characteristic and a salient pole rotor, the rotary condition of which is definable in tErms of a rotor frequency which is referenced to the stator winding, said method comprising the steps of: a. providing an adjustable stator current for the motor; b. sensing the existing rotor frequency of the rotor; c. establishing the frequency of the stator current responsive to the sensed rotor frequency to a value equal to the value of the existing rotor frequency under all operating conditions of the motor; d. altering the magnitude of the stator current responsive to the sensed rotor frequency to a value prescribed solely as a predetermined function of the desired motor torque condition when the quadrature axis flux appears so that the direct axis flux remains constant relative to the desired motor torque condition regardless of the voltage condition of the synchronous reluctance motor to permit motoring and regenerative operation of the motor; and e. concurrently establishing the phase displacement of the stator current at a predetermined displacement angle prescribed solely as a predetermined function of the desired motor torque condition, f. the concurrent predetermined establishment of the stator current magnitude and phase angle values being such as to tend to fix the direct axis flux of the motor at a desired level while generating a predetermined torque producing quadrature axis flux and the desired torque condition in the motor.
Claim 3
Dependent Claim
70 words
The method of claim 1 wherein the stator winding is energized by a stator current phase displaceable with respect to the direct axis flux and wherein the step of establishing the phase displacement of the stator current is further defined as concurrently establishing the phase displacement of the stator current with respect to the direct axis flux at values tending to fix the direct axis flux at the desired level.
Claim 4
Dependent Claim
111 words
The method of claim 1 further defined as a method for changing the condition of the motor from an existing torque condition to a newly desired torque condition the method being further defined as including the step of concurrently reestablishing the magnitude and phase displacement of the stator current at new values prescribed solely as predetermined functions of the newly desired motor torque condition, the concurrent predetermined reestablishment of the stator current magnitude and phase angle values being such as to tend to retain the direct axis flux of the motor at the desired level while generating an altered quadrature axis flux and the newly desired torque condition in the motor.
Claim 5
Dependent Claim
75 words
The method of claim 3 wherein the stator winding is energized by a stator current phase displaceable with respect to the direct axis flux and wherein the step of reestablishing the phase displacement of the stator current is further defined as concurrently reestablishing the phase displacement of the stator current with respect to the direct axis flux to a value tending to retain the direct axis flux at the desired level under altered torque conditions.
Claim 6
Dependent Claim
66 words
The method of claim 1 for producing torque conditions for driving the motor at a preselected speed, said method including the step of detecting a motor speed error and said method is further defined as concurrently establishing the magnitude and phase displacement values of the stator current responsive to the motor speed error for producing torque conditions in the motor tending to reduce the speed error.
Claim 7
Dependent Claim
33 words
The method of claim 5 including the further step of concurrently limiting stator current magnitude and phase displacement values under excessive speed error conditions to limit the output torque condition of the motor.
Claim 8
Dependent Claim
46 words
The method of claim 1 wherein the step of providing the stator current is further defined as providing an adjustable unidirectional current and the step of establishing the frequency of the stator current is further defined as cyclically directing the unidirectional current to the stator winding.
Claim 9
Dependent Claim
155 words
The method of claim 1 further defined as including the steps of: providing a signal quantitatively proporTional to an arbitrarily desired motor torque condition to be developed in the motor; modifying the torque condition signal to provide a stator current magnitude control signal, said modification occurring as a predetermined function of the quantitative characteristic of the motor torque condition signal and independently of the ascertainment of existing motor conditions; establishing the magnitude of the stator current in accordance with the stator current magnitude control signal; modifying the torque condition signal to provide a stator current phase displacement control signal, said modification occurring as a predetermined function of the quantitative characteristic of the motor torque condition signal and independently of the ascertainment of existing motor conditions; and establishing the phase displacement of the stator current in accordance with the stator current phase displacement control signal, said establishment occurring concurrently with the establishment of stator current magnitude.
Claim 10
Dependent Claim
108 words
The method of claim 8 further defined as a method for changing the condition of the motor from an existing torque condition to a newly desired torque condition including the steps of: changing the torque condition signal to that corresponding the newly desired torque condition and modifying the changed torque condition signal to provide altered stator current magnitude and phase displacement control signals; and simultaneously reestablishing the magnitude and phase displacement of the stator current at new values tending to retain the direct axis flux of the motor at the desired level while generating an altered quadrature axis flux and the newly desired torque condition in the motor.
Claim 11
Dependent Claim
71 words
The method of claim 8 for producing torque conditions for driving the motor at a preselected speed, including the step of detecting motor speed error and providing said speed error as the torque condition signal, said method being further defined as concurrently establishing the magnitude and phase displacement values of the stator current responsive to motor speed error for producing torque conditions in the motor tending to reduce the speed error.
Claim 12
Dependent Claim
33 words
The method of claim 10 including the further step of concurrently limiting stator current magnitude and phase displacement values under excessive speed error conditions to limit the output torque condition of the motor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |