US4879754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed controller
Assignee: Panasonic Holdings Corp
•
Filing: 1989-03-14
•
Granted: 1989-11-07
•
Expires: 2009-03-14
Abstract
Abstract The invention provides a speed controller which detects the period of an AC signal containing information of the rotational speed of a motor and controls the rotational speed based on the detected period value and a reference speed value. More particularly, the speed controller computes the amount of the deviation of the AC signal based on continuously detected period values and the reference speed value, and then stores the computed deviation amount in a memory as a correction value. Using the correction value stored in the memory, the speed controller corrects the deviation of the period, and thus, the speed of the rotation of the motor can be controlled with extremely high precision.
Inventors
- 👤 Kunihira Tadashi
- 👤 Hiroshi Minakuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:55
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/2805; H02P23/00; H02P23/16; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/904; Y10S388/907; Y10S388/909; Y10S388/912; Y10S388/916; Y10S388/921
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
96 words
A speed controller comprising: period detecting means for detecting a period of alternating-current (AC) signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected period value and a reference speed value; driving means for supplying said rotating object with a driving power based on said error output; and correction-value computing means for computing a correction value from two continuous detected period values stored in said memory and the reference speed value.
Claim 2
Dependent Claim
96 words
A speed controller comprising: period detecting means for detecting a period of alternating-current (AC) signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected period value and a reference speed value; driving means for supplying said rotating object with a driving power based on said error output; and correction-value computing means for computing a correction value from two continuous detected period values stored in said memory and the reference speed value.
Claim 3
Dependent Claim
70 words
A speed controller as defined in claim 1, further comprising channel selecting means for renewing address of said memory means whenever said period detecting means detects periods covering at least two periods of the AC signal and then comparing the period values stored in the corresponding addresses of said memory means with the reference speed value to obtain the error output corresponding to a difference between the compared period values.
Claim 4
Dependent Claim
148 words
A speed controller comprising: period detecting means for detecting a period of an AC signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected period value and a reference speed value; driving means for supplying said rotating object with a driving signal based on said error output; correction-value computing means for computing first and second displacement amounts from two continuous detected period values stored in said memory means and the reference speed value and then computing a correction value of said error output from the first and second displacement amounts when a subtracted value of said first and second displacement amounts is substantially constant; and error-output correcting means for causing said calculating means to correct said error output by using said correction value.
Claim 5
Dependent Claim
148 words
A speed controller comprising: period detecting means for detecting a period of an AC signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected period value and a reference speed value; driving means for supplying said rotating object with a driving signal based on said error output; correction-value computing means for computing first and second displacement amounts from two continuous detected period values stored in said memory means and the reference speed value and then computing a correction value of said error output from the first and second displacement amounts when a subtracted value of said first and second displacement amounts is substantially constant; and error-output correcting means for causing said calculating means to correct said error output by using said correction value.
Claim 6
Dependent Claim
48 words
A speed controller as defined in claim 3, further comprising gain-changing means for decreasing the gain of the control system below a normal gain level when said correction-value computing means is operated for computing the correction value from the subtracted value of said first and second displacement amounts.
Claim 7
Dependent Claim
25 words
A speed controller as defined in claim 3, further comprising monitor means for monitoring that the output from said error-output correcting means is substantially constant.
Claim 8
Dependent Claim
40 words
A speed controller as defined in claim 5, wherein said corrective-value computing means again executes an arithmetic operation to process the correction value when said monitor means identifies that the output from said error-output correcting means is not substantially constant.
Claim 9
Dependent Claim
149 words
A speed controller comprising: period detecting means for detecting a period of an AC signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected value and a reference speed value; driving means for supplying said rotating means with a driving signal based on said error output; correction-value computing means for computing first and second displacement amounts from two continuous detected period values stored in said memory means and the reference speed value and then computing a correction value of said reference speed value from the first and second displacement amounts when a subtracted value of said first and second displacement amounts is substantially constant; and reference speed value correcting means for correcting the reference speed value for each period by using said correction value.
Claim 10
Dependent Claim
149 words
A speed controller comprising: period detecting means for detecting a period of an AC signal containing information of a rotational speed of a rotating object; memory means for storing the detected period value detected by said period detecting means; calculation means for calculating an error output from said detected value and a reference speed value; driving means for supplying said rotating means with a driving signal based on said error output; correction-value computing means for computing first and second displacement amounts from two continuous detected period values stored in said memory means and the reference speed value and then computing a correction value of said reference speed value from the first and second displacement amounts when a subtracted value of said first and second displacement amounts is substantially constant; and reference speed value correcting means for correcting the reference speed value for each period by using said correction value.
Claim 11
Dependent Claim
48 words
A speed controller as defined in claim 7, further comprising gain-changing means for decreasing the gain of the control system below a normal gain level when said correction-value computing means is operated for computing the correction value from the subtracted value of said first and second displacement amounts.
Claim 12
Dependent Claim
58 words
A speed controller as defined in claim 7, further comprising monitor means for monitoring that the error output computed by said calculation means is substantially constant, wherein said calculation means calculates said error output by using the reference speed value, correction value computed by said correction-value computing means, and the period value detected by said period detecting means.
Claim 13
Dependent Claim
36 words
A speed controller as defined in claim 9, wherein said correction-value computing means again executes an arithmetic operation to process the correction value when said monitor means identifies that the error output is not substantially constant.
References Cited (Backward Citations)
US4283671A
Cited
US4488096A
Cited
JPS5718434A
Cited
US4371819A
Cited
US4628314A
Cited
US4675585A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |