Patent US4503376A successfully refreshed from Google Patents.
US4503376A
Expired / Lapsed
US
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Control method for induction motors
Assignee: Hitachi Ltd
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Filing: 1983-10-04
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Granted: 1985-03-05
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Expires: 2003-10-04
Abstract
Abstract A quick response vector control method which is one of methods for controlling a speed of an induction motors without a speed detector; in which a voltage of the motor is detected to resolve into a vector component e d parallel with an exciting current component vector of a primary current and a vector component e q orthogonal to said exciting current component vector, and a frequency of the primary current is controlled to maintain the vector component e d at zero, while at the same time the primary current is controlled corresponding to a difference between the vector component e q and the speed command signal.
Inventors
- 👤 Toshiaki Okuyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:23
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/14; H02P21/18; H02P21/24; H02P21/26; H02P2207/00; H02P2207/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
140 words
A vector control method for induction motor for independently controlling a torque current component and an exciting current component of the primary current supplied to an induction motor through the control of an amplitude and a frequency of the primary current, comprising the steps of: detecting a motor voltage of said induction motor; resolving said motor voltage into a vector component e d parallel with an exciting current component of the primary current and a vector component e q orthogonal to said exciting current component vector; and controlling a frequency of said primary current so that said vector component e d of said motor voltage is zeroed, while at the same time controlling said primary current corresponding to a difference between said vector component e q and a speed command signal, thereby to control the speed of said induction motor.
Claim 2
Dependent Claim
140 words
A vector control method for induction motor for independently controlling a torque current component and an exciting current component of the primary current supplied to an induction motor through the control of an amplitude and a frequency of the primary current, comprising the steps of: detecting a motor voltage of said induction motor; resolving said motor voltage into a vector component e d parallel with an exciting current component of the primary current and a vector component e q orthogonal to said exciting current component vector; and controlling a frequency of said primary current so that said vector component e d of said motor voltage is zeroed, while at the same time controlling said primary current corresponding to a difference between said vector component e q and a speed command signal, thereby to control the speed of said induction motor.
Claim 3
Dependent Claim
53 words
A vector control method according to claim 1, further comprising the step of detecting a difference between said vector component e q and a command value of said vector component e q , thereby to automatically set said vector component e q equally to said command value by controlling said exciting current component.
Claim 4
Dependent Claim
33 words
A vector control method according to claim 1, further comprising the step of adding a signal component corresponding to a slip frequency to said speed command signal to provide another speed command signal.
Claim 5
Dependent Claim
34 words
A vector control method according to claim 1, further comprising the step of adding a signal component corresponding to a slip frequency in negative polarity to a negative terminal of a speed difference amplifier.
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) | 1988-03-04 | 1988-09-03 | 1989-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-04 | 1992-09-03 | 1993-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-04 | 1996-09-03 | 1997-03-05 | $7700.00 | Window Closed / Lapsed |