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WO1999051941A1 - Procede de calcul de la moyenne - Google Patents

Procede de calcul de la moyenne Download PDF

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Publication number
WO1999051941A1
WO1999051941A1 PCT/DE1999/000944 DE9900944W WO9951941A1 WO 1999051941 A1 WO1999051941 A1 WO 1999051941A1 DE 9900944 W DE9900944 W DE 9900944W WO 9951941 A1 WO9951941 A1 WO 9951941A1
Authority
WO
WIPO (PCT)
Prior art keywords
value
frequency
signal
time
values
Prior art date
Application number
PCT/DE1999/000944
Other languages
German (de)
English (en)
Inventor
Wilfried Meyer
Original Assignee
Mannesmann Rexroth Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mannesmann Rexroth Ag filed Critical Mannesmann Rexroth Ag
Publication of WO1999051941A1 publication Critical patent/WO1999051941A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D1/00—Measuring arrangements giving results other than momentary value of variable, of general application
    • G01D1/02—Measuring arrangements giving results other than momentary value of variable, of general application giving mean values, e.g. root means square values

Definitions

  • the invention relates to a method for forming the mean value of a number of temporally successive samples of a time-varying signal, in which the mean value is calculated by mathematically linking a number of successive samples, according to the preamble of claim 1.
  • Averages generally serve to characterize a set of numbers.
  • for. B. differentiate between the arithmetic, the geometric and the quadratic mean.
  • the individual numbers are added and the sum divided by the number of added numbers.
  • the geometric mean the individual numbers are multiplied together and the root corresponding to the number of multiplied numbers is taken from the product.
  • the quadratic mean the squares of the numbers are added, the square root is taken from the sum and the result is divided by the number of numbers.
  • Characterization of periodic waveforms e.g. B. of electrical voltages or currents, in particular the temporally linear mean and the effective value are used.
  • the linear mean in time corresponds to the arithmetic mean
  • the effective value corresponds to the root mean square.
  • a predetermined number of temporally successive sample values of this signal are linked to one another by the digital computing device in accordance with a calculation rule.
  • the calculated mean value is only output by the computing device when the predetermined number of samples has been taken into account when calculating the mean value. This ensures that a sufficient number of samples has always been taken into account for the calculation of the mean value.
  • DE 43 37 388 AI discloses a method for averaging according to the preamble of claim 1. Temperature values determined at constant time intervals within a 24-hour period are added and the sum is divided by the number of added temperature values. A new updated mean value is available at the time intervals specified by the measurement value acquisition.
  • the mean value is usually formed in each case over a period of the fundamental wave of the signal curve.
  • the frequency of the fundamental oscillation is not constant, but can assume values of different sizes between two limit values, additional demands are placed on the averaging.
  • a sufficiently large number of samples must be acquired within one period.
  • short times between two sampling processes lead to a large memory requirement for the sample values occurring within one period of the fundamental wave.
  • DE 39 28 083 C2 discloses a circuit for measuring a measured variable derived from the root mean square of an AC voltage, in particular the effective value of an AC voltage.
  • the AC voltage to be measured is divided into a low-frequency and a higher-frequency voltage component.
  • the low-frequency voltage component is digitally squared after digitization.
  • the higher-frequency voltage component is squared using an analog squaring circuit and then digitized. The two digital values are added and the desired measured variable is calculated from the sum by averaging.
  • the invention is based on the object of specifying a method of the type mentioned at the outset in which a new mean value is available in short time intervals and for the averaging of time-varying ones periodic waveforms with a frequency of the fundamental oscillating between two limit values is suitable.
  • the method enables a moving averaging for periodic signal curves, in which the frequency of the fundamental wave can assume different values between two limit values, with a small memory requirement.
  • the subclaims relate to a further reduction in the memory requirement, the storage of the sample values and the use of the method according to the invention.
  • Figure 1 is a block diagram of a device for forming the average of a number of prematurely successive samples
  • Figure 2 shows the course of a time-varying, periodic signal.
  • FIG. 1 shows the block diagram of an apparatus for forming the mean value of a time-varying signal according to the invention.
  • a voltage u (t) serves a voltage u (t) as a time-varying signal.
  • the voltage u (t) has a generally periodic course, ie a fundamental oscillation U Q (t) is superimposed on oscillations of a higher frequency.
  • the time course of the voltage u (t) is shown on an enlarged scale in FIG.
  • a scanning device 20 samples the amplitude of the voltage u (t) at equal time intervals.
  • An analog / digital converter 21 converts the sample values present in analog form into corresponding digital values and transfers them to a first memory 22.
  • the second memory 23 is followed by a second memory 23 serving as a buffer.
  • the memories 22 and 23 each have only eight memory locations, each of which is designated by M1 to M8. In practice, however, the number of storage locations provided for storing the sample values is considerably larger. It is in the order of 4000 storage locations.
  • a digital computing device 24, e.g. B. a microcontroller calculates the mean value from the numbers stored in the memory locations of the memory 23 by mathematically linking these numbers using an algorithm for calculating the mean value. For the description of the exemplary embodiment, it is assumed that the effective value of the voltage u (t) is to be formed. In this case, the squares of the samples are added, the roots are taken from the sum and the result is divided by the number of samples used for averaging.
  • the mean value of the voltage u (t) is still present in digital form at an output 25 of the computing device 24.
  • the mean can either be processed further in digital form or in in a manner known per se can be converted into an analog value.
  • a first control line 26 leads from the computing device 24 to the scanning device 20.
  • Two further control lines 27 and 28 lead to the memories 22 and 23, respectively.
  • FIG. 2 shows the time profile of the voltage u (t) over two periods, which are denoted by T1 and T2.
  • the voltage u (t) consists of a fundamental wave u 0 (t) shown in dashed lines and this superimposed vibrations of higher frequency. Since the voltage u (t) has a periodic course, it is necessary to determine at least one period of the fundamental wave for the formation of the effective value.
  • the amplitude of the voltage u (t) is detected at times t 0 to t 17 .
  • the corresponding samples are designated A Q to A 17 .
  • the period between two sampling times is constant, it is referred to as ⁇ t below.
  • the memory locations M1 to M8 in the memory 22 contain the samples A- j _ to A 8 .
  • the contents of the memories Ml to M8 of the memory 22 are transferred to the memories Ml to M8 of the memory 23, the memory locations that Ml to M8 of the memory 23 is also included after the samples A to A ⁇ _. 8
  • the computing device 24 calculates the effective value at the time t 8 , which takes into account the sample values of the period T1, that is to say the sample values A 1 to A 8 .
  • the sample values A 2 to A 8 are shifted from the memory locations M2 to M8 of the memory 22 to the memory locations M1 to M7.
  • the value stored in memory location Ml sample A j _ from the sample A 2 is overwritten.
  • the contents of the storage locations M3 to M8 are shifted to the storage locations M2 to M7 in a corresponding manner.
  • the memory location M8 is then available for storing a new sample value.
  • the sample values A - j _ to A 8 provided for calculating the effective value at time t are still available in memory 23.
  • the computing device 24 causes the scanning device 20 to scan the voltage u (t) again via the control line 26.
  • the sampled voltage value is converted into the digital value A g and in that
  • Storage space M8 of the memory 22 is stored.
  • the memory locations Ml to M8 of the memory 22 now contain the samples A 2 to Ag, that is to say eight samples again, which cover the period of a period of the fundamental oscillation of the voltage u (t) up to the time tg.
  • the contents of the memory locations M1 to M8 of the memory 22 are now transferred to the corresponding memory locations of the memory 23 by a control command from the computing device 24.
  • the computing device 24 calculates a new effective value from the values transferred to the memory 23. This effective value is already a sampling time ⁇ t after the previous effective value.
  • the samples A 8 to A 9 shifted from memory locations M2 to M8 of memory 22 to memory locations M1 to M7.
  • the sample value A 2 stored in the memory location M1 is overwritten by the sample value A 3 .
  • the contents of the storage locations M3 to M8 are shifted to the storage locations M2 to M7 in a corresponding manner.
  • the memory location M8 is then available again for storing a new sample value.
  • the sample values A 2 to Ag provided for the calculation of the effective value are still available in the memory 23.
  • the computing device 24 again causes the scanning device 20 to scan the voltage u (t).
  • the sampled voltage value is converted into a digital value A 10 and stored in the memory location M8.
  • the memory locations M1 to M8 of the memory 22 now contain the sample values A3 to A ] _ Q , that is to say eight sample values again, which cover the period of a period of the fundamental oscillation of the voltage u (t) from the time t 3 to the time t 10 .
  • the contents of the memory locations M1 to M8 of the memory 22 are transferred to the corresponding memory locations of the memory 23 by a control command from the computing device 24.
  • the calculating means calculates from the transmitted values in the memory 23, 24 - as described above '- a new RMS value. This RMS value is also already a sampling time ⁇ t after the previous RMS value. This means that a new effective value of the voltage u (t) is present after each sampling time.
  • the memory 23 can be omitted. There is no need to shift the sample values in the memory 22 if the new sample value overwrites the respectively oldest sample value.
  • the new sample replaces the oldest sample in memory.
  • the other sample values are retained in the memory, so that the mean value is calculated on the basis of the latest sample values.
  • the frequency of the fundamental wave u 0 (t) can assume different values within a range between two limit values fomin un ⁇ ⁇ ⁇ Omax, it must be ensured that at the highest frequency oma ' a l so if the period is minimum, a minimum number N mj _ n is from necessary for the averaging of samples are available.
  • the relationship T (f 0max ) applies to the relationship between the period T (f 0max ) of the fundamental wave with the greatest frequency fomax ' ⁇ er time it t between two sampling processes and the minimum number N mj _ n of the sampling values required for averaging.
  • N ma ⁇ the number of memory spaces resulting in frequency.
  • N max N max x ⁇ t ( equation 2 )
  • T (f 0m i n ) the reciprocal of the frequency r ⁇ min i st •
  • the 4000 memory locations are sufficient up to a lower cut-off frequency, namely up to 0.1 Hz.
  • a lower lower limit frequency can be achieved without having to increase the number of memory locations.
  • the output signal of this link is also a periodic signal, which consists of a basic oscillation and higher-frequency oscillations superimposed.
  • the frequency of the fundamental wave of the output signal is equal to the known frequency of the input signal. The frequency of the basic oscillation of the output signal therefore does not need to be determined separately from the output signal for the change in the time between the scanning processes as a function of the frequency of the basic oscillation. 12
  • the multiplicative correction of a setpoint signal fed to a control chain requires, depending on the quotient of the mean value of the setpoint signal and the mean value at the end of the control chain detected actual value signal takes place, no additional damping measures to be taken. This improves the effectiveness of the corrective action.
  • LMS multiplicative correction of the setpoint signal

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Oscillators With Electromechanical Resonators (AREA)

Abstract

L'invention concerne un procédé de calcul de la moyenne d'un nombre de valeurs d'échantillonnage consécutives d'un signal variable dans le temps. Dans le procédé selon l'invention, on combine un nombre de valeurs d'échantillonnage selon une règle de calcul correspondante. S'il s'agit de signaux périodiques, on calcule typiquement la moyenne sur une période entière de l'oscillation de l'onde fondamentale du signal périodique. Pour les tracés de courbe périodiques du signal, dans lesquels la fréquence de la composante fondamentale peut prendre des valeurs différentes comprises entre une limite supérieure et une limite inférieure, on sélectionne la durée entre deux échantillonnages de façon à mémoriser, pour la plus grande fréquence, le nombre minimum de valeurs d'échantillonnage nécessaires au calcul de la moyenne pendant une période de la composante fondamentale.
PCT/DE1999/000944 1998-04-01 1999-03-26 Procede de calcul de la moyenne WO1999051941A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19814622 1998-04-01
DE19814622.1 1998-04-01

Publications (1)

Publication Number Publication Date
WO1999051941A1 true WO1999051941A1 (fr) 1999-10-14

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DE (1) DE19913753A1 (fr)
WO (1) WO1999051941A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002012909A3 (fr) * 2000-08-09 2002-11-21 Teradyne Inc Capture et evaluation de flux de donnees a grande vitesse
US7143323B2 (en) 2002-12-13 2006-11-28 Teradyne, Inc. High speed capture and averaging of serial data by asynchronous periodic sampling
US8980950B2 (en) 2002-11-26 2015-03-17 GlaxoSmithKline, LLC Calcilytic compounds

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19946626A1 (de) * 1999-09-29 2001-04-26 Micronas Gmbh Verfahren und Vorrichtung zur Aufbereitung eines Messsignales
DE10256176B4 (de) * 2002-12-02 2006-06-22 Infineon Technologies Ag Verfahren und Vorrichtung zur Bildung des Mittelwertes eines periodischen Signals
DE102009024492A1 (de) * 2009-06-10 2010-12-16 Bayerische Motoren Werke Aktiengesellschaft Verfahren zur Signalerfassung einer mit einer variablen Signalfrequenz schwingenden Messgröße

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3905735A1 (de) * 1989-02-24 1990-08-30 Pierburg Gmbh Verfahren zum auswerten eines eingangssignals
DE4337388A1 (de) * 1992-11-02 1994-05-05 Vaillant Joh Gmbh & Co Verfahren zur außentemperaturgeführten Steuerung/Regelung eines Heizgerätes

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3905735A1 (de) * 1989-02-24 1990-08-30 Pierburg Gmbh Verfahren zum auswerten eines eingangssignals
DE4337388A1 (de) * 1992-11-02 1994-05-05 Vaillant Joh Gmbh & Co Verfahren zur außentemperaturgeführten Steuerung/Regelung eines Heizgerätes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002012909A3 (fr) * 2000-08-09 2002-11-21 Teradyne Inc Capture et evaluation de flux de donnees a grande vitesse
US6694462B1 (en) 2000-08-09 2004-02-17 Teradyne, Inc. Capturing and evaluating high speed data streams
KR100816468B1 (ko) * 2000-08-09 2008-03-26 테라다인 인코퍼레이티드 고속 데이터 스트림을 캡쳐하여 평가하는 방법 및 장치
US8980950B2 (en) 2002-11-26 2015-03-17 GlaxoSmithKline, LLC Calcilytic compounds
US7143323B2 (en) 2002-12-13 2006-11-28 Teradyne, Inc. High speed capture and averaging of serial data by asynchronous periodic sampling

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