CN101795107B - Method for detecting motor speed - Google Patents
Method for detecting motor speed Download PDFInfo
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- CN101795107B CN101795107B CN2010101470913A CN201010147091A CN101795107B CN 101795107 B CN101795107 B CN 101795107B CN 2010101470913 A CN2010101470913 A CN 2010101470913A CN 201010147091 A CN201010147091 A CN 201010147091A CN 101795107 B CN101795107 B CN 101795107B
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Abstract
The invention provides a method for detecting the motor speed, which is used for detecting the motor speed at extremely-low speed and high speed. The method for detecting the motor speed is used for calculating the motor speed by adopting customized pulse sampling interval to replace pulse sampling interval under the condition without changing the pulse sampling interval and a speed control period. The invention ensures that accurate detection of average speed of the motor becomes possible,can realize the stable speed control in an extremely-low speed range and at high speed of the motor by using rapid speed-adjusting characteristics, and effectively lowers the cost of a speed control system by using a low-cost pulse coder with low resolution.
Description
The application is January 20 2009 applying date, application number 200910095727.1, the dividing an application of denomination of invention " method for detecting motor speed ".
Technical field
The present invention relates to the motor detection technique, specifically, relate to a kind of method for detecting motor speed, only use the pulse coder of low resolution to carry out the motor speed detection, can obtaining more accurately, motor speed is used for Electric Machine Control.
Background technology
In a motor speed control system; if only use a pulse coder with suitable low resolution; when motor rotates with low-down speed; the adjacent time interval (each rising edge of a pulse cycle or trailing edge cycle) of the pulse that obtains from pulse coder usually can be greater than motor speed control cycle and impulse sampling at interval; thereby at speed control neither one pulse signal in the cycle, to such an extent as to can't obtain motor speed feedback information accurately.
The resolution that tests the speed characterizes the susceptibility of measurement mechanism to rotation speed change, tests the speed down at the low resolution pulse coder, and the resolution that tests the speed is
P is an encoder line number, T
pBe the impulse sampling interval.In near zero motor low-speed range, as shown in Figure 1, establishing the speed control cycle is T
s=T, the impulse sampling interval T
p=T
s, the 0/T/2T/....../nT time point is the beginning in each speed control cycle:
During t=T, there is not pulse between t=0～T, the motor speed n=0 that calculates;
During t=2T, detect a pulse between t=T～2T, the motor speed n=n1=Q that calculates.
Easily know motor actual speed n=n1/2 by figure, so when carrying out speed control, can not get actual motor speed all the time and carry out closed-loop control.The reason that produces this resolution that tests the speed exactly is not enough, exists adjacent pulse interval greater than the impulse sampling interval T
pThe low speed situation, promptly with the resolution P and the impulse sampling interval T of pulse coder
pRelevant, improving the resolution Q that tests the speed has following dual mode:
1) improve the resolution P of pulse coder, i.e. line number, thereby revolution cross the umber of pulse that a circle obtains and become many, do not change the impulse sampling interval T under the low speed
pThe time, can so that the adjacent pulse time interval less than impulse sampling at interval.
2) increase the impulse sampling interval T
p, when not changing pulse coder resolution P under the low speed, can so that the adjacent pulse time interval less than impulse sampling at interval.
But this dual mode all has certain restriction, and the resolution of pulse coder can not infinitely promote, and high-resolution pulse coder must make cost strengthen; The impulse sampling interval T
pCan have influence on the speed control period T
s, speed control period T under the common speed control
s〉=T
p, the impulse sampling interval T
pIncrease will make T
sBecome big, and cross senior general and make that the system responses of speed control is slack-off, can't realize high performance of control the speed control cycle.
Do not changing under suitable pulse coder resolution and the impulse sampling situation at interval, can carry out The disposal of gentle filter by speed feedback, thereby improve motor speed resolution, level and smooth speed responsive the pulsation that obtains.But, add filter and can produce phase lag, do not have can also meet the demands under specific (special) requirements and the non-low speed, under utmost point low speed, the motor speed that obtains is not steady.And from realizing considering that also there is certain restriction in filter order, too high will the making of exponent number realizes becoming complicated, and phase lag is bigger, and exponent number is not enough, in some cases again can not level and smooth effectively velocity perturbation.
Summary of the invention
The object of the present invention is to provide a kind of method for detecting motor speed, it can be at utmost point low speed and at a high speed, do not change under the impulse sampling interval and the situation in speed control cycle, adopt self-defined impulse sampling to substitute impulse sampling at interval at interval, the feasible resolution that tests the speed is improved, speed feedback is more accurate, and speed control is more stable.
Technical problem solved by the invention can realize by the following technical solutions:
A first aspect of the present invention is to provide a kind of method for detecting motor speed under the low speed situation, this method for detecting motor speed, in the motor speed testing process, the speed control cycle that has zero pulse, it is characterized in that: for each speed control cycle, the natural several times that adopt the raw velocity sampling interval are as new speed sampling interval, calculate the interior at interval umber of pulse of new speed sampling, and calculate the motor speed in this speed control cycle according to new speed sampling interval and the new interior at interval umber of pulse of speed sampling.
Among the present invention,, comprise that with contiguous this speed control cycle before this speed control cycle continuous zero pulse speed control periodicity+1 times of raw velocity sampling interval in this speed control cycle is as new speed sampling interval to the zero pulse speed control cycle.
To the non-zero pulses speed control cycle, the continuous zero pulse speed control periodicity in this speed control cycle of vicinity+1 times of raw velocity sampling interval as new speed sampling at interval before with this speed control cycle.
A second aspect of the present invention is to provide a kind of method for detecting motor speed under high-speed case, this method for detecting motor speed, in the motor speed testing process, each speed control has at least one pulse in the cycle, it is characterized in that: with the umber of pulse of a certain speed control in the cycle as the reference pulse number, according to raw velocity sampling interval and reference pulse number calculating benchmark motor speed, the umber of pulse in each speed control cycle deducts the reference pulse number and obtains adjusting umber of pulse, produce the speed control cycle of zero adjustment pulse thus, the natural several times that adopt the raw velocity sampling interval for each speed control cycle are as new speed sampling interval, calculate the interior at interval adjustment umber of pulse of new speed sampling, and according to new speed sampling at interval and the adjustment umber of pulse of new speed sampling at interval calculate the adjustment motor speed in this speed control cycle, benchmark motor speed and adjust the motor speed sum and be motor speed and feed back.
Among the present invention, to the speed control cycle of zero adjustment pulse, comprise with contiguous this speed control cycle before this speed control cycle this speed control cycle continuous zero adjustment pulse the speed control periodicity+1 times raw velocity sampling interval as new speed sampling at interval.
To the speed control cycle of non-zero adjustment pulse, with speed control periodicity+1 times raw velocity sampling interval of the continuous zero adjustment pulse in contiguous this speed control cycle before this speed control cycle as new speed sampling at interval.
For the motor speed that detects when the motor high speed has higher precision, average with the maximum number of pulses in speed control cycle and minimum pulse number and to round as the reference pulse number again, the maximum number of pulses difference that the present invention is most appropriate to the speed control cycle is not more than 2 situation.
The present invention is on the basis that does not change the speed control cycle, make that detecting accurate motor average speed becomes possibility, and utilize speed fast to adjust characteristic can be implemented in the utmost point low-speed range and the stabilized speed control during the motor high speed, because adopted the low-cost pulse coder of low resolution, reduced the cost of speed control system effectively simultaneously.
Description of drawings
Fig. 1 is under the motor low speed situation, prior motor speed detection method schematic diagram.
Fig. 2 for the present invention under motor low speed situation, the method for detecting motor speed schematic diagram.
Fig. 3 for the present invention under the motor high-speed case, the method for detecting motor speed schematic diagram.
Embodiment
For technological means, creation characteristic that the present invention is realized, reach purpose and effect is easy to understand, below in conjunction with concrete diagram, further set forth the present invention.
In the existing speed detection method, paired pulses is zero speed control cycle, and the motor speed in its cycle is zero; For the non-vanishing speed control cycle of pulse, the motor speed in its cycle
Wherein M is this speed control detected umber of pulse in the cycle, and P is an encoder line number, T
pBe the impulse sampling interval.
When the motor high speed, each speed control cycle (impulse sampling interval T
pEquate with the speed control cycle) in can detect pulse, but when motor low speed, speed control may detect pulse in the cycle, also may not have.
As shown in Figure 2, the speed control cycle of motor and original impulse sampling interval T
pBe T, in the cycle, only detect pulse at speed control cycle 0-T, 2T-3T, 5T-6T, 6T-7T in preceding 7 speed control.Shown in Fig. 2 d, according to existing speed detection method, the motor speed of speed control cycle 0-T, 2T-3T, 5T-6T, 6T-7T is n0, the motor speed in other speed control cycles is zero, concrete computational process is not major part of the present invention, and those skilled in the art understand this process and are not repeated at this.This be since this moment motor be in lower-speed state, the resolution of pulse coder is not enough, be not enough in each speed control cycle (impulse sampling at interval), detect pulse, so when carrying out speed control, can not get actual motor speed all the time and carry out closed-loop control.
For the speed control cycle that does not detect pulse under low speed also can be fed back a realistic motor speed, at original pulse sampling interval T
pUnder constant situation of speed control cycle, impulse sampling virtual amplification at interval can be about to original pulse sampling interval T
pBe amplified to new impulse sampling interval T '
P=L
p, (L is a natural number).Thereby new impulse sampling interval T '
PDetect M pulse in time, then the motor speed in this speed control cycle
Wherein, M be new impulse sampling interval T '
PInterior detected umber of pulse.
Referring to Fig. 2 b, 2c, below describe each speed control cycle in detail and be how with original pulse sampling interval T
pCarry out processing and amplifying and obtain motor speed.Speed control cycle 0-T detects pulse (being the non-zero pulses speed control cycle) since this speed control cycle be first speed control cycle, no zero pulse speed control cycle before it, thus new impulse sampling interval T of this speed control cycle '
pBe (0+1) T
p, obtain the motor speed n=n1=n0 of speed control cycle 0-T.
Speed control period T-2T does not detect pulse (being the zero pulse speed control cycle), in this speed control before the cycle, comprise that speed control period T-2T only has speed control period T-2T from as the zero pulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
pBe (1+1) T
p, obtain the motor speed n=n2=n0/2 of speed control period T-2T.
Pass through said method, can obtain continuous motor speed, and corresponding motor speed n1, n2, n3, its speed detection resolution is brought up to 1,1/2,1/3 of original resolution respectively, present embodiment is under motor low speed situation, and motor speed result of calculation is more accurate.
Embodiment 2
When motor was in fast state, each speed control cycle all can detect pulse, and shown in Fig. 3 a, each speed control cycle all has at least one pulse.When handling, the umber of pulse that can adopt a certain speed control cycle is as the reference pulse number, more accurate processing mode is to average with the maximum number of pulses in speed control cycle and minimum pulse number to round as the reference pulse number again, for example the maximum number of pulses of present embodiment medium velocity control cycle is 3, the minimum pulse number is 1, therefore the reference pulse number should choose 2, if be not integer after the maximum number of pulses in speed control cycle and minimum pulse number average, then the definite reference pulse number in back can rounded.
After determining the reference pulse number, can be according to reference pulse number and original pulse sampling interval T
pCalculate benchmark motor speed N, computational methods had been carried out description at preamble, also were not repeated at this.The umber of pulse in each speed control cycle deducts the reference pulse number and obtains adjusting umber of pulse then, shown in Fig. 3 b, originally umber of pulse is that 2 speed control period T-2T, 3T-4T, the adjustment umber of pulse of 4T-5T, 6T-7T are zero, originally umber of pulse is that the adjustment umber of pulse of 3 speed control cycle 0-T, 5T-6T is 1, originally umber of pulse is that the adjustment pulse of 1 speed control cycle 2T-3T is a negative pulse, therefore adjusts umber of pulse and calculates with-1.
Can calculate the adjustment motor speed in each speed control cycle by the adjustment umber of pulse that obtains, the motor speed feedback is the benchmark motor speed and adjusts the motor speed sum.Fig. 3 e has shown the adjustment motor speed that existing method is calculated, the adjustment motor speed of speed control period T-2T, 3T-4T, 4T-5T, 6T-7T is 0, the adjustment motor speed of speed control cycle 0-T, 5T-6T is n0, the adjustment motor speed of speed control cycle 2T-3T is-n0, the adjustment motor speed in each speed control cycle is added the benchmark motor speed can obtain the motor speed feedback, but because benchmark motor speed and adjustment motor speed all are at original pulse sampling interval T
pCalculate down, so the precision of motor speed feedback is not very high.
So in the present embodiment, it is also identical with embodiment 1 to adjust motor speed, at original pulse sampling interval T
pUnder constant situation of speed control cycle,, be about to original pulse sampling interval T with impulse sampling virtual amplification at interval
pBe amplified to new impulse sampling interval T '
p=LT
P, (L is a natural number), thus new impulse sampling interval T '
PDetect M pulse in time, calculate the adjustment motor speed with this.
Referring to Fig. 3 c, 3d, the adjustment umber of pulse of speed control cycle 0-T is 1 (being non-zero adjustment impulse speed control cycle), no zero adjustment impulse speed control cycle before it, so new impulse sampling interval T of this speed control cycle '
PBe (0+1) T
p, obtaining the adjustment motor speed n=n1=n0 of speed control cycle 0-T, the motor speed feedback of speed control cycle 0-T is N+n0.
The adjustment umber of pulse of speed control period T-2T is 0 (being zero adjustment impulse speed control cycle), in this speed control before the cycle, comprise that speed control period T-2T only has speed control period T-2T from as zero adjustment impulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
PBe (1+1) T
p, obtaining the adjustment motor speed n=n2=n0/2 of speed control period T-2T, the motor speed feedback of speed control period T-2T is N+n0/2.
The adjustment umber of pulse of speed control cycle 2T-3T is-1 (being non-zero adjustment impulse speed control cycle), in this speed control contiguous speed control period T-2T only being arranged before the cycle is zero adjustment impulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
PBe (1+1) T
p, obtaining the adjustment motor speed n=-n2=-n0/2 of speed control cycle 2T-3T, the motor speed feedback of speed control cycle 2T-3T is N-n0/2.
It is 0 (being zero adjustment impulse speed control cycle) that speed control cycle 3T-4T adjusts umber of pulse, in this speed control before the cycle, comprise that speed control cycle 3T-4T only has speed control cycle 3T-4T from as zero adjustment impulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
PBe (1+1) T
p, obtaining the motor speed n=-n2=-n0/2 of speed control cycle 3T-4T, the motor speed feedback of speed control cycle 3T-4T is N-n0/2.
It is 0 (being zero adjustment impulse speed control cycle) that speed control cycle 4T-5T adjusts umber of pulse, in this speed control before the cycle, comprise speed control cycle 4T-5T, contiguous speed control cycle 3T-4T and speed control cycle 4T-5T be from as zero adjustment impulse speed control cycle continuously, so new impulse sampling interval T of this speed control cycle '
PBe (2+1) T
p, obtaining the adjustment motor speed n=-n3=-n0/3 of speed control cycle 4T-5T, the motor speed feedback of speed control cycle 4T-5T is N-n0/3.
It is 1 (being non-zero adjustment impulse speed control cycle) that speed control cycle 5T-6T adjusts umber of pulse, this speed control before the cycle contiguous speed control cycle 3T-4T and speed control cycle 4T-5T be continuous zero adjustment impulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
PBe (2+1) T
p, obtaining the adjustment motor speed n=n3=n0/3 of speed control cycle 5T-6T, the motor speed feedback of speed control cycle 5T-6T is N+n0/3.
It is 0 (being zero adjustment impulse speed control cycle) that speed control cycle 6T-7T adjusts umber of pulse, in this speed control before the cycle, comprise that speed control cycle 6T-7T only has speed control cycle 6T-7T from as zero adjustment impulse speed control cycle, so new impulse sampling interval T of this speed control cycle '
PBe (1+1) T
p, obtaining the adjustment motor speed n=n2=n0/2 of speed control cycle 6T-7T, the motor speed feedback of speed control cycle 6T-7T is N+n0/2.The follow-up speed control cycle can be adopted and be calculated the adjustment motor speed in a like fashion, is not repeated at this.Similar to embodiment 1, motor is under high-speed case, and speed calculation result is also more accurate.
In fact, method for present embodiment, the maximum number of pulses difference that is most appropriate to the speed control cycle is not more than 2 situation, because when the maximum number of pulses difference greater than 2 the time, the absolute value that must have a speed control cycle adjustment umber of pulse is greater than 1, make that the adjustment impulse speed of calculating is accurate inadequately, finally reduced the precision of detected motor speed feedback.Therefore, the less situation of velocity perturbation when the method for present embodiment is more suitable for the motor high speed, thus can feed back more accurate motor speed.
More than show and described basic principle of the present invention and principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; that describes in the foregoing description and the specification just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.
Claims (5)
1. method for detecting motor speed, in the motor speed testing process, each speed control has at least one pulse in the cycle, it is characterized in that: with the umber of pulse of a certain speed control in the cycle as the reference pulse number, according to original pulse sampling interval and reference pulse number calculating benchmark motor speed, the umber of pulse in each speed control cycle deducts the reference pulse number and obtains adjusting umber of pulse, produce the speed control cycle of zero adjustment pulse thus, the natural several times that adopt the original pulse sampling interval for each speed control cycle are as new impulse sampling interval, calculate the interior at interval adjustment umber of pulse of new impulse sampling, and according to new impulse sampling at interval and the adjustment umber of pulse of new impulse sampling at interval calculate the adjustment motor speed in this speed control cycle, benchmark motor speed and adjust the motor speed sum and be motor speed and feed back.
2. method for detecting motor speed as claimed in claim 1, it is characterized in that: to the speed control cycle of zero adjustment pulse, comprise with contiguous this speed control cycle before this zero adjustment impulse speed control cycle this speed control cycle continuous zero adjustment pulse the speed control periodicity+1 times original pulse sampling interval as new impulse sampling at interval.
3. method for detecting motor speed as claimed in claim 1 or 2, it is characterized in that: to the speed control cycle of non-zero adjustment pulse, with speed control periodicity+1 times original pulse sampling interval of the continuous zero adjustment pulse in contiguous this speed control cycle before this non-zero adjustment impulse speed control cycle as new impulse sampling at interval.
4. method for detecting motor speed as claimed in claim 1 is characterized in that: average with the maximum number of pulses in speed control cycle and minimum pulse number and round as the reference pulse number again.
5. method for detecting motor speed as claimed in claim 4 is characterized in that: the maximum number of pulses in speed control cycle and minimum pulse are counted difference and are not more than 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010101470913A CN101795107B (en) | 2009-01-20 | 2009-01-20 | Method for detecting motor speed |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010101470913A CN101795107B (en) | 2009-01-20 | 2009-01-20 | Method for detecting motor speed |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009100957271A Division CN101478285B (en) | 2009-01-20 | 2009-01-20 | Motor speed detection method |
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| CN101795107A CN101795107A (en) | 2010-08-04 |
| CN101795107B true CN101795107B (en) | 2011-10-05 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6401624B2 (en) * | 2015-02-06 | 2018-10-10 | 株式会社アイエイアイ | Motor control method and apparatus |
| CN111240374B (en) * | 2019-12-27 | 2023-10-31 | 深圳市合信自动化技术有限公司 | Method for detecting micro speed |
| CN111239433B (en) * | 2020-02-18 | 2022-03-15 | 日立楼宇技术（广州）有限公司 | Rate sampling method and device and rate sampling equipment |
| CN111865172B (en) * | 2020-07-22 | 2024-03-22 | 东南大学盐城新能源汽车研究院 | Accurate estimation method for motor rotation speed of servo system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1580784A (en) * | 2004-05-18 | 2005-02-16 | 桂林星辰电力电子有限公司 | Method for measuring motor speed at low-speed operation by using pulse coder |
| CN101086506A (en) * | 2006-06-09 | 2007-12-12 | 西门子公司 | Method for determining the speed of a motor vehicle and device for carrying out the method |
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2009
- 2009-01-20 CN CN2010101470913A patent/CN101795107B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1580784A (en) * | 2004-05-18 | 2005-02-16 | 桂林星辰电力电子有限公司 | Method for measuring motor speed at low-speed operation by using pulse coder |
| CN101086506A (en) * | 2006-06-09 | 2007-12-12 | 西门子公司 | Method for determining the speed of a motor vehicle and device for carrying out the method |
Non-Patent Citations (1)
| Title |
|---|
| JP特开平6-118090A 1994.04.28 |
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