US6009003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current/voltage control apparatus for elevator system
Assignee: Otis Elevator Korea Co Ltd
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Filing: 1998-01-06
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Granted: 1999-12-28
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Expires: 2018-01-06
Abstract
Abstract A current/voltage control apparatus for an elevator system which is capable of preventing an over current from being applied to an inverter by stopping a driving operation of the inverter when a difference (hereinafter called "current deviation") between a current instruction and actual current value exceed a predetermined value during a predetermined time. The apparatus includes a voltage limiter for setting a limit voltage value which is proportional to an operational frequency of the induction motor and applying the voltage below the limit voltage value to the inverter driving unit, a zero phase component current detector for detecting a zero phase component current and outputting an inverter driving stop signal to the inverter driving unit when the thusly detected current exceeds a predetermined reference value, and a current deviation detector for detecting a current deviation value and outputting an inverter driving stop signal to the inverter driving unit when the current deviation value, which exceeds a predetermined reference value, is continuously maintained for a predetermined time.
Inventors
- 👤 Hwan Je Yeo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:51
CPC Classifications
B; B66; B66B; B66B1/00; B66B1/24; H; H02; H02M; H02M1/00; H02M1/32; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H02M7/53875; H02P; H02P21/00; H02P21/06; H02P21/10
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
194 words
A current/voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into an alternating-current voltage of a variable voltage-and-frequency-type to be applied to an induction motor, an inverter controller for detecting a current phase flowing in the induction motor, generating a voltage instruction based on the detected phase and controlling the inverter, and an inverter driving unit for receiving an output signal from the inverter controller, generating a pulse width modulation signal corresponding thereto and driving the inverter, said control apparatus comprising: a voltage limiter for setting a limit voltage value which is proportional to an operational frequency of the induction motor and applying the voltage below the limit voltage value to the inverter driving unit; a zero phase component current detector for detecting a zero phase component current and outputting an inverter driving stop signal to the inverter driving unit when the thusly detected current exceeds a predetermined reference value; and a current deviation detector for detecting a current deviation value and outputting an inverter driving stop signal to the inverter driving unit when the current deviation value exceeds a predetermined reference value continuously for a predetermined time.
Claim 2
Dependent Claim
194 words
A current/voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into an alternating-current voltage of a variable voltage-and-frequency-type to be applied to an induction motor, an inverter controller for detecting a current phase flowing in the induction motor, generating a voltage instruction based on the detected phase and controlling the inverter, and an inverter driving unit for receiving an output signal from the inverter controller, generating a pulse width modulation signal corresponding thereto and driving the inverter, said control apparatus comprising: a voltage limiter for setting a limit voltage value which is proportional to an operational frequency of the induction motor and applying the voltage below the limit voltage value to the inverter driving unit; a zero phase component current detector for detecting a zero phase component current and outputting an inverter driving stop signal to the inverter driving unit when the thusly detected current exceeds a predetermined reference value; and a current deviation detector for detecting a current deviation value and outputting an inverter driving stop signal to the inverter driving unit when the current deviation value exceeds a predetermined reference value continuously for a predetermined time.
Claim 3
Dependent Claim
43 words
The apparatus of claim 1, wherein said voltage limiter outputs a limit voltage value which is proportional to the operational frequency after a predetermined voltage is maintained for a predetermined time after the operation of the same, and a predetermined time is elapsed.
Claim 4
Dependent Claim
75 words
The apparatus of claim 1, wherein said zero phase component current detector includes: a summing unit for summing three-phase currents, thus obtaining a zero phase component current; a comparator for comparing the zero phase component current value with a predetermined reference value; and a latch unit for outputting an inverter driving stop signal to the inverter driving unit when the zero phase component current value exceeds a predetermined value as a result of the comparison.
Claim 5
Dependent Claim
34 words
The apparatus of claim 1, wherein said current deviation value is a difference value between a current instruction with respect to a torque component and a magnetic component and an actually detected current value.
Claim 6
Dependent Claim
118 words
A current voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into a variable voltage-and-frequency-type of alternating-current voltage to be applied to an induction motor, and an inverter controller for detecting a current phase flowing in the induction motor, for generating a voltage instruction based on the detected phase and for controlling the inverter, said control apparatus comprising: a voltage limiter to limit maximum values of control signals from said inverter controller as a function of an operation frequency of said induction motor, said voltage limiter producing upper-bounded control signals; and an inverter driving unit for generating a pulse width modulation signal to drive said inverter based upon said upper-bounded control signals.
Claim 7
Dependent Claim
118 words
A current voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into a variable voltage-and-frequency-type of alternating-current voltage to be applied to an induction motor, and an inverter controller for detecting a current phase flowing in the induction motor, for generating a voltage instruction based on the detected phase and for controlling the inverter, said control apparatus comprising: a voltage limiter to limit maximum values of control signals from said inverter controller as a function of an operation frequency of said induction motor, said voltage limiter producing upper-bounded control signals; and an inverter driving unit for generating a pulse width modulation signal to drive said inverter based upon said upper-bounded control signals.
Claim 8
Dependent Claim
60 words
The control apparatus of claim 5, wherein, after said upper-bounded control signals reach a maximum value, respectively, said voltage limiter is operable to maintain said upper-bounded control signals at the maximum values thereof, respectively, for a predetermined time, after which said voltage limiter is operable to make said upper-bounded control signals proportional to said operation frequency of said induction motor.
Claim 9
Dependent Claim
44 words
The control apparatus of claim 5, further comprising: a zero-phase-component current detector to detect a zero phase component current and to output an inverter driving stop signal to said inverter driving unit when said current detector determines said current exceeds a predetermined reference value.
Claim 10
Dependent Claim
43 words
The control apparatus of claim 7, wherein a plurality of motor currents are applied to drive said induction motor, and said current detector is operable to add said plurality of motor currents to produce a sum against which said predetermined reference is compared.
Claim 11
Dependent Claim
39 words
The control apparatus of claim 5, further comprising: a current deviation detector to detect a current deviation value and to output an inverter driving stop signal to said inverter driving unit when said deviation value exceeds a reference value.
Claim 12
Dependent Claim
30 words
The control apparatus of claim 9, wherein said deviation detector is operable to output said stop signal after said deviation value has exceeded said reference value for a preset time.
Claim 13
Dependent Claim
153 words
A current voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into a variable voltage-and-frequency-type of alternating-current voltage to be applied to an induction motor, said control apparatus comprising: a voltage limiter to produce upper-bounded control signals; an inverter driving unit for generating a pulse width modulation signal to drive said inverter based upon said upper-bounded control signals; a zero-phase-component current detector to detect a zero phase component current flowing in the induction motor and to provide a first inverter driving stop signal to said inverter driving unit when said zero-phase-component current detector determines that said current exceeds a predetermined reference value; and a current deviation detector to provide a second inverter driving stop signal to said inverter driving unit based upon at least one of a Q-axis current derived from motor currents flowing in said induction motor and a D-axis current derived from said motor currents.
Claim 14
Dependent Claim
153 words
A current voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into a variable voltage-and-frequency-type of alternating-current voltage to be applied to an induction motor, said control apparatus comprising: a voltage limiter to produce upper-bounded control signals; an inverter driving unit for generating a pulse width modulation signal to drive said inverter based upon said upper-bounded control signals; a zero-phase-component current detector to detect a zero phase component current flowing in the induction motor and to provide a first inverter driving stop signal to said inverter driving unit when said zero-phase-component current detector determines that said current exceeds a predetermined reference value; and a current deviation detector to provide a second inverter driving stop signal to said inverter driving unit based upon at least one of a Q-axis current derived from motor currents flowing in said induction motor and a D-axis current derived from said motor currents.
Claim 15
Dependent Claim
43 words
The control apparatus of claim 11, wherein a plurality of motor currents are applied to drive said induction motor, and said current detector is operable to add said plurality of motor currents to produce a sum against which said predetermined reference is compared.
Claim 16
Dependent Claim
45 words
The control apparatus of claim 11, wherein said second inverter driving stop signal is based upon at least one of a first error between a Q-axis current and a corresponding Q-axis instruction and a second error between a D-axis current and a corresponding D-axis instruction.
Claim 17
Dependent Claim
26 words
The control apparatus of claim 11, wherein said second inverter driving stop signal is based upon a difference between said first error and said second error.
Claim 18
Dependent Claim
26 words
The control apparatus of claim 14, wherein said second inverter driving stop signal is generated if said difference exceeds a reference value for a minimum duration.
References Cited (Backward Citations)
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