CN101393231B - Fast and high precision speed-measuring method for motor - Google Patents

Abstract

The present invention relates to a method for quickly measuring speed with high precision, in particular to a method for quickly measuring the speed of a motor with high precision. By labeling a Hall signal of the detected motor, the rotation rate of the motor which is accurately acquired by using a small section of signal in the rotation process of the motor is realized. Under the condition of stable speed, and the magnitude relation of the lengths of three Hall signals which are generated during the process of one complete revolution of the detected motor is labeled for determining the corresponding relation of a Hall element and different poles during the actual operation. Meanwhile, the trace and the positioning of the corresponding poles of the Hall signals during the operation process of the motor are completed. The primary advantage of the method is to use the small section of the signal generated during one complete revolution of the motor to accurately acquire the rotating speed of the motor speed. The quick and highly-precise speed measurement is realized.

Description

Motor is carried out high precision speed-measuring method fast

Technical field

The present invention relates to high precision speed-measuring method fast, particularly a kind of motor is carried out high precision speed-measuring method fast.

Background technology

In engineering practice, run into the various occasions that need to measure rotating speed through regular meeting, for example in the trial run and control of slewings such as engine, motor, windlass, machine tool chief axis, often need timesharing or continuous coverage, show its rotating speed or transient speed.At present, digital rotating speed measurement method commonly used mainly contains three kinds, is respectively M method (frequency method), T method (periodic method) and M/T method (frequency/period method).The M method is in set detection time, measures the number of the rotational speed pulse signal that is produced and determines rotating speed, is suitable for measuring at a high speed; The T method is the time of measuring adjacent two rotational speed pulse signals to measure rotating speed, is suitable for low speed and measures; The M/T method be measure simultaneously detection time and at this moment between in the number of rotational speed pulse signal determine rotating speed.

Hall element output waveform error is mainly by the Hall element alignment error, and rotor magnetic pole processing and alignment error influence produce.Inoperative when the Hall element alignment error is only measured one road hall signal (the back error is cancelled out each other because rotate a circle), it is 0 that rotor magnetic pole processing and alignment error can make its add up error by the measurement integer number of turns.For having the brshless DC motor of N, turn over N square wave of each Hall element output of a week to p-m rotor.That is to say N Hall waveform of each measurement one road hall signal, the range rate error that the Hall waveform error is brought is 0.During low speed, adopt T to test the speed usually and measure the time that motor rotates a circle.The T velocimetry is the cycle velocimetry, calculates the method for motor rotational shaft speed by the cycle of measuring the Hall element pulsing.The measurement of recurrence interval is to obtain indirectly by the time clock that a certain clock frequency is determined.If clock frequency is f _c, the time clock that records is m, then motor used time that rotates a circle is: $T=\frac{m}{f_c},$ Then motor speed is: $n=\frac{60f_c}{m}.$ The error of m is ± 1 when testing the speed.But this method is measured the time in a week when low speed longer, has only behind the hall signal that records a week and just can know velocity amplitude, and there is hysteresis quality in the relative actual value of the velocity amplitude that records, and measuring speed just becomes a prominent question.Be subjected to significant limitation in the practical application, as in high-precision flywheel attitude control, requiring has higher real-time, and this method just can not meet the demands.Need speed-measuring method more fast, can in the shorter time, accurately record rotating speed of motor.

Summary of the invention

The objective of the invention is the contradiction of measuring period and precision when solving above-mentioned background technology low speed, obtain high precision velocity measuring method fast, both energy measurement low speed is provided, at a high speed a kind of of energy measurement carries out high precision speed-measuring method fast to motor again.

The present invention carries out high precision speed-measuring method fast to motor, it is characterized in that carrying out according to the following steps:

A. adding the high precision uniform speed electric motor outside drags down hall signal is demarcated, the hall signal waveform of determining to rotate a circle motor A, B in the process, C three road hall signals producing under the different magnetic poles effect, under speed stabilizing, measure hall signal time t1～t18 that three road hall signals produce under the different magnetic poles effect, t be adding up of t1～t18 and, for motor rotate a week used time-the abbreviation cycle;

B. calculate step a and record the number percent that hall signal time t1～t18 that three road hall signals produce accounts for whole cycle t separately under the different magnetic poles effect $\mathrm{di}=\frac{\mathrm{ti}}{t},$ I=1 in the formula～18;

C. before motor enters normal duty, deposit magnitude relationship data and the corresponding magnetic pole of tA1, tA2, tA3 in data-carrier store, wherein tA1=t1+t2+t3, tA2=t7+t8+t9, tA3=t13+t14+t15 are the high level time section of A phase Hall priority correspondence in one week.Judge the magnetic pole of the current correspondence of A phase hall signal then according to the current tA1 that records, tA2, tA3, finish the tracking of hall signal and corresponding magnetic pole, thus from next can judge constantly the time span that at every turn records be t1～t18 which, enter the process that tests the speed of normal operation;

D. during the value of any one in recording t1～t18, utilize and survey measured proportionate relationship in advance and just can calculate motor accurately and rotate a circle the used time: $T=\frac{\mathrm{ti}}{\mathrm{di}},$ Wherein ti is some among the t1～t18 that measures in the real-world operation process, and di is the ratio of this time period correspondence, thereby can calculate motor speed is: $n=\frac{60\mathrm{di}}{\mathrm{ti}},$ If clock frequency is f _c, the time clock that ti recorded in the time period is m, motor speed is: $n=\frac{60\mathrm{di}\·f_c}{m}.$

For A, B, any one road hall signal of C, the existence of Hall element alignment error, stator coil and rotor magnetic pole mismachining tolerance makes that in the process that motor rotates a circle, the hall signal length of generation is also inequality under speed stabilizing.In the process that rotates a circle under speed stabilizing according to motor, three hall signal length scale relations of generation just can judge that the current location of Hall element and different magnetic poles concerns in the real-world operation process.The location of therefore realizing Hall element and different magnetic poles just can know that ti is among t1～t18 which in the real-world operation process, and next signal can obtain in proper order.

The inventive method has the following advantages with respect to existing traditional speed-measuring method:

The contradiction that this method has solved low speed in the above-mentioned background technology when measuring between cycle and the precision;

This method has good real-time performance, and there is hysteresis quality in the relative actual value of velocity amplitude that has reduced to record;

This method is utilized rotate a circle 1/18 signal in the process of motor, has realized that precise speed is measured fast, and the peripheral speed Measuring Time has improved 18 times.

Description of drawings

Fig. 1 is a measuring principle synoptic diagram of the present invention;

Fig. 2 to Fig. 7 is a magnetic pole tracing and positioning principal diagram intention of the present invention.

Embodiment

Below in conjunction with embodiment the inventive method is further elaborated.

Embodiment 1

Adopt the inventive method that dc brushless motor is carried out high precision speed-measuring method fast, carry out according to the following steps:

A. adding the high precision uniform speed electric motor outside drags down hall signal is demarcated, the hall signal waveform of determining to rotate a circle motor A, B in the process, C three road hall signals producing under the different magnetic poles effect, accurately measure hall signal time t1～t18 that three road hall signals produce under the different magnetic poles effect under speed stabilizing, t is that motor rotates all used time.Shown in Figure 1 as shining, the Hall element output waveform is mainly by the Hall element alignment error, and stator coil and rotor magnetic pole mismachining tolerance produce.It is not accurately to equal 120 ° (120 ° of installations of three Halls) that the Hall element alignment error makes the phase differential between any two-way hall signal, and it is not accurately to equal 50% that stator coil and rotor magnetic pole mismachining tolerance make the dutycycle of one road hall signal.The time end that the rising edge of the hall signal waveform reference hall signal that A, B, C three road hall signals produce under three pairs of magnetic pole effects, negative edge trigger pulse can be divided into different interval.(can with reference to Fig. 1)

Because after dc brushless motor making, the installation, Hall element alignment error, dc brushless motor rotor magnetic pole mismachining tolerance, coil winding distributional difference just are fixed up to the various influences of hall signal.Under speed stabilizing, accurately measure hall signal time t1～t18 that three road hall signals produce under the different magnetic poles effect, t1 is a high level for hall signal A, B is a low level, C is the high level time section, t2 is a high level for hall signal A, B is a low level, C is the low level time section, t3 is a high level for hall signal A, B is a high level, C is the low level time section, t4 is a low level for hall signal A, B is a high level, C is the low level time section, t5 is a low level for hall signal A, B is a high level, C is the high level time section, t5 is a high level for hall signal A, B is a low level, C is the high level time section, t6 is a low level for hall signal A, B is a low level, C is the high level time section, t7 is a high level for hall signal A, B is a low level, C is the high level time section, t8 is a high level for hall signal A, B is a low level, C is the low level time section, t3 is a high level for hall signal A, B is a high level, C is the low level time section, t9 is a low level for hall signal A, B is a high level, C is the low level time section, t10 is a low level for hall signal A, B is a high level, C is the high level time section, t11 is a high level for hall signal A, B is a low level, C is the high level time section, t12 is a low level for hall signal A, B is a low level, C is that high level time section t1 is a high level for hall signal A, B is a low level, C is the high level time section, t13 is a high level for hall signal A, B is a low level, C is the low level time section, t14 is a high level for hall signal A, B is a high level, C is the low level time section, t4 is a low level for hall signal A, B is a high level, C is the low level time section, t15 is a low level for hall signal A, B is a high level, C is the high level time section, t5 is a high level for hall signal A, B is a low level, C is the high level time section, t16 is a low level for hall signal A, B is a low level, C is the high level time section, t=t1+t2+...+t18.T is that motor rotates all used time.Under different speed stabilizing values, t, though the size of t1～t18 is different, the number percent that t1～t18 accounts for whole cycle t separately is consistent.

B. calculate the actual percentage that t1～t18 accounts for whole cycle t separately $\mathrm{di}=\frac{\mathrm{ti}}{t},$ I=1～18 (do not having under any influences such as Hall alignment error, magnetic pole mismachining tolerance, stator winding distribution error, the number percent that t1～t18 accounts for whole cycle t separately equates).

C. should organize the number percent data deposits in the reservoir; Calculate tA1=t1+t2+t3, tA2=t7+t8+t9, tA3=t13+t14+t15, and the magnitude relationship of tA1, tA2, tA3 relatively.Magnitude relationship and the corresponding magnetic pole of tA1, tA2, tA3 are concerned that depositing data in deposits in the reservoir.When tA1 is maximum, the tA3 minimum, tA2 deposits triadic relation tA1＞tA2＞tA3 in reservoir (as shown in Figure 2) between the two the time; When tA1 is maximum, the tA2 minimum, tA3 deposits triadic relation tA1＞tA3＞tA2 in reservoir (as shown in Figure 3) between the two the time; When tA2 is maximum, the tA3 minimum, tA1 deposits triadic relation tA2＞tA1＞tA3 in reservoir (as shown in Figure 4) between the two the time; When tA2 is maximum, the tA1 minimum, tA3 deposits triadic relation tA2＞tA3＞tA1 in reservoir (as shown in Figure 5) between the two the time; When tA3 is maximum, the tA2 minimum, tA1 deposits triadic relation tA3＞tA1＞tA2 in reservoir (as shown in Figure 6) between the two the time; When tA3 is maximum, the tA1 minimum, tA2 deposits triadic relation tA3＞tA2＞tA1 in reservoir (as shown in Figure 7) between the two the time.Before motor enters normal duty, can experience one by static process to speed stabilizing.After motor speed stabilizing a period of time, be written into magnitude relationship data and the corresponding magnetic pole relation data of tA1, tA2, tA3, judge the magnetic pole of the current correspondence of A phase hall signal according to the current tA1 that records, tA2, tA3.As shown in table 1, when storage data when being tA1＞tA2＞tA3, if record all A mutually after the time span of three hall signals, if the time tAx of current A phase Hall is three the maximum in the data, can judge that the minor time slice ti that next records constantly is t4, i.e. i=4.If the time tAx of current A phase Hall is three intermediate in the data, can judge that the minor time slice ti that next records constantly is t10, i.e. i=10..If the time tAx of current A phase Hall is three recklings in the data, can judge that the minor time slice ti that next records constantly is t16, i.e. i=16..Can fully know constantly that from next the time span that at every turn records is which (other situation can the table of comparisons 1) t1～t18 thus.Thereby finish the tracking of the corresponding magnetic pole of hall signal.

Table 1

The storage relation	Record relation	Judge ti	Record relation	Judge ti	Record relation	Judge ti
							tA1>tA2>tA3	tA1>tA2>tA3	t16	tA2>tA3>tA1	t10	tA3>tA1>tA2	t4
tA1>tA3>tA2	tA1>tA3>tA2	t16	tA3>tA2>tA1	t10	tA2>tA1>tA3	t4
							tA2>tA3>tA1	tA2>tA3>tA1	t16	tA3>tA1>tA2	t10	tA1>tA2>tA3	t4
tA2>tA1>tA3	tA2>tA1>tA3	t16	tA1>tA3>tA2	t10	tA3>tA2>tA1	t4
							tA3>tA1>tA2	tA3>tA1>tA2	t16	tA1>tA2>tA3	t10	tA2>tA3>tA1	t4
tA3>tA2>tA1	tA3>tA2>tA1	t16	tA2>tA1>tA3	t10	tA3>tA2>tA1	t4

D. enter the process that tests the speed of normal operation.During any one value in recording t1～t18, utilize and survey measured proportionate relationship in advance and just can calculate motor accurately and rotate a circle the used time: $T=\frac{\mathrm{ti}}{\mathrm{di}},$ Wherein ti is some among the t1～t18 that measures in the real-world operation process, and di is the ratio of this time period correspondence, thereby can calculate motor speed is: $n=\frac{60\mathrm{di}}{\mathrm{ti}},$ If clock frequency is f _c, the time clock that ti recorded in the time period is m, motor speed is: $n=\frac{60\mathrm{di}\·f_c}{m}.$

Claims (1)

1. one kind is carried out high precision speed-measuring method fast to motor, it is characterized in that carrying out according to the following steps:

A. adding the high precision uniform speed electric motor outside drags down hall signal is demarcated, the hall signal waveform of determining to rotate a circle motor A, B in the process, C three road hall signals producing under the different magnetic poles effect, under speed stabilizing, measure hall signal time t1～t18 that three road hall signals produce under the different magnetic poles effect, t be adding up of t1～t18 and, be motor rotate a week used time-the abbreviation cycle;

B. calculate step a and record the number percent that hall signal time t1～t18 that three road hall signals produce accounts for whole cycle t separately under the different magnetic poles effect $\mathrm{di}=\frac{\mathrm{ti}}{t},$ I=1 in the formula～18;

C. before motor enters normal duty, with tA1, tA2, magnitude relationship data and the corresponding magnetic pole of tA3 deposit data-carrier store in, tA1=t1+t2+t3 wherein, tA2=t7+t8+t9, tA3=t13+t14+t15, high level time section for A phase Hall priority correspondence in one week, then according to the current tA1 that records, tA2, tA3 judges the magnetic pole of the current correspondence of A phase hall signal, finish the tracking of hall signal and corresponding magnetic pole, thus from next can judge constantly the time span that at every turn records be t1～t18 which, enter the process that tests the speed of normal operation;

D. during the value of any one in recording t1～t18, utilize and survey measured proportionate relationship in advance and just can calculate motor accurately and rotate a circle the used time: $t=\frac{\mathrm{ti}}{\mathrm{di}},$ Wherein ti is some among the t1～t18 that measures in the real-world operation process, and di is the ratio of this time period correspondence, thereby can calculate motor speed is: $n=\frac{60\mathrm{di}}{\mathrm{ti}},$ If clock frequency is f _c, the time clock that ti recorded in the time period is m, motor speed is: $n=\frac{60\mathrm{di}\·f_c}{m}.$

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