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US6043624A
Expired / Lapsed
US
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Motor control method and motor control system
Assignee: Hitachi Ltd
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Filing: 1998-06-10
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Granted: 2000-03-28
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Expires: 2018-06-10
Abstract
Abstract In an a.c. motor control method and apparatus, operations are carried out at a current controller and a voltage setting using interrupt signals generated in synchronism with maximum and minimum values of a carrier wave at a control device for controlling an inverter for driving an alternating current motor. In operations at the voltage setting part carried out using one of the interrupt signals, a carrier wave is corrected in such a manner that phases of voltage command values gradually come into synchronism with a carrier wave. An integral multiple of the period of the carrier wave becomes the period of the a.c. voltage and current control operation timing is carried out in synchronism with the carrier wave.
Inventors
- 👤 Ryozo Masaki
- 👤 Yoshitaka Iwaji
- 👤 Satoru Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:57
CPC Classifications
H; H02; H02P; H02P21/00; H02P21/22
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
72 words
A system for controlling a synchronous motor, comprising: a power conversion device for supplying power to said synchronous motor; and a pulse width modulation control device for generating a pulse width modulation signal by comparing a voltage command value of an a.c. voltage and a carrier wave and controlling said power conversion device; wherein a period of said carrier wave is compensated for using an angle of rotation of said synchronous motor.
Claim 2
Independent Claim
72 words
A system for controlling a synchronous motor, comprising: a power conversion device for supplying power to said synchronous motor; and a pulse width modulation control device for generating a pulse width modulation signal by comparing a voltage command value of an a.c. voltage and a carrier wave and controlling said power conversion device; wherein a period of said carrier wave is compensated for using an angle of rotation of said synchronous motor.
Claim 3
Dependent Claim
132 words
A motor control system comprising: carrier wave generating means for generating first and second carrier waves having a prescribed difference; pulse width modulation control means for generating first and second pulse width modulation signals by comparing an a.c. voltage command value and said first and second carrier waves, respectively; an inverter having at least one pair of positive side and negative side switching elements, said switching elements being driven by said first and second pulse width modulation signals, for generating a voltage; and means for causing said first and second pulse width modulation signals to be applied to said positive side and negative side switching elements, alternately in first and second modes; wherein a frequency of said carrier waves is an even-numbered multiple of a frequency of said a.c. voltage command value.
Claim 4
Dependent Claim
132 words
A motor control system comprising: carrier wave generating means for generating first and second carrier waves having a prescribed difference; pulse width modulation control means for generating first and second pulse width modulation signals by comparing an a.c. voltage command value and said first and second carrier waves, respectively; an inverter having at least one pair of positive side and negative side switching elements, said switching elements being driven by said first and second pulse width modulation signals, for generating a voltage; and means for causing said first and second pulse width modulation signals to be applied to said positive side and negative side switching elements, alternately in first and second modes; wherein a frequency of said carrier waves is an even-numbered multiple of a frequency of said a.c. voltage command value.
Claim 5
Independent Claim
104 words
A system for controlling an a.c. motor, comprising: control means for calculating an a.c. voltage command value based on a comparison of an a.c. motor current of said motor and an a.c. current command value; pulse width modulation signal generating means for generating a pulse width modulation signal by comparing said a.c. voltage command value and a carrier wave; a power conversion device for supplying power to said a.c. motor using said pulse width modulation signal; and means for changing a frequency of said carrier wave when an output current of a frequency of 1/10 or more of a reference carrier frequency is generated.
Claim 6
Independent Claim
104 words
A system for controlling an a.c. motor, comprising: control means for calculating an a.c. voltage command value based on a comparison of an a.c. motor current of said motor and an a.c. current command value; pulse width modulation signal generating means for generating a pulse width modulation signal by comparing said a.c. voltage command value and a carrier wave; a power conversion device for supplying power to said a.c. motor using said pulse width modulation signal; and means for changing a frequency of said carrier wave when an output current of a frequency of 1/10 or more of a reference carrier frequency is generated.
Claim 7
Independent Claim
111 words
A method for controlling an a.c. motor, comprising: comparing a current of said a.c. motor and a current command value; calculating an a.c. voltage command value to be applied to said a.c. motor from results of said comparison; generating a pulse width modulation signal by comparing said a.c. voltage command value and a carrier wave; and applying an a.c. voltage to said a.c. motor using said pulse width modulation signal; wherein operation timing of said a.c. voltage command value is in synchronism with said carrier wave; and a frequency of said carrier wave is equal to N times (where N is an integer) a frequency of said a.c. voltage command value.
Claim 8
Independent Claim
111 words
A method for controlling an a.c. motor, comprising: comparing a current of said a.c. motor and a current command value; calculating an a.c. voltage command value to be applied to said a.c. motor from results of said comparison; generating a pulse width modulation signal by comparing said a.c. voltage command value and a carrier wave; and applying an a.c. voltage to said a.c. motor using said pulse width modulation signal; wherein operation timing of said a.c. voltage command value is in synchronism with said carrier wave; and a frequency of said carrier wave is equal to N times (where N is an integer) a frequency of said a.c. voltage command value.
Claim 9
Dependent Claim
43 words
The method of claim 4, wherein a period of said carrier wave is determined based on changes in the speed of said a.c. motor so that a phase of said carrier wave is in synchronism with a prescribed phase of said a.c. voltage.
Claim 10
Dependent Claim
12 words
The method of claim 4, wherein N is a multiple of 3.
Claim 11
Dependent Claim
28 words
The method of claim 4, wherein an operation period of said a.c. voltage command value is an integral multiple of 1/2 of a period of said carrier wave.
Claim 12
Dependent Claim
66 words
The method of claim 4, further comprising: generating first and second carrier waves having a prescribed difference; generating first and second pulse width modulation signals by comparing said a.c. voltage command value and said first and second carrier waves; alternatively outputting said first and second pulse width modulation signals; and driving respective positive and negative side switching elements forming a pair for a power conversion device.
Claim 13
Dependent Claim
34 words
The method of claim 4, wherein said carrier wave is obtained using a digital counter; and one of a maximum value and a minimum value of said carrier wave is usually the same value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-03-28 | 2003-09-27 | 2004-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-28 | 2007-09-27 | 2008-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-28 | 2011-09-27 | 2012-03-28 | $7700.00 | Window Closed / Lapsed |