JPS58167969A - Measurement of effective value - Google Patents

Abstract

PURPOSE:To enable accurate measurement of effective values with limited errors in the computation accompanied by frequency variations in the waveform of the AC input by correcting a sampling value of the AC input waveform with a deviation between the actual frequency and the reference frequency. CONSTITUTION:An AC input waveform obtained through a potential transformer 1 undergoes an A/D conversion detecting two sampling values having a fixed phase difference pi/2 in the reference frequency f0 with an A/D converter 2. A frequency transducer 3, outputs a level signal proportional to the frequency f0 of the AC input waveform to be fed the A/D converter 2. The A/D conversion outputs thus obtained is sent to an effective value arithmetic unit 4 and one of sampling data is corrected by a phase pi DELTAf0/2f0 according to a variation value DELTAf0 of an actual frequency f0' from the reference frequency f0 to form a data with a relative phase difference separated just by pi/2 whereby an effective value is calculated. This enables the correction of errors in the computation of a digital effective value accompanied by variations in the AC input frequency.

Description

[Detailed description of the invention] A few examples of sajutsu minute needles.

This paper relates to an effective value measurement method in which an AC input waveform is sampled at a predetermined sampling frequency, and the sampled value is used to calculate the AC human power effective value by LA calculation. This relates to a corrector IR for eliminating errors.

There are various methods of sampling the current input waveform at an additional sampling frequency and calculating the AC human power effective value using the Tempering value. The effective value calculation jl original block, which can be called "principle", is often used.

This AM performance 3! Raw salt is T determined from the AC input waveform.
This is a digital additive calculation method that calculates an effective value from two arbitrary sampling values. An example is '(%)
= Vs&+2g10t, the value of V is the sample t(tl-
-L-) to 4f.

V""r" (11) + r" (tl -" -)
−−−−−−−−−(L)10 can be calculated as follows.Using this calculation formula, it is possible to calculate
Two-ll! ! l#i does not occur.

Normally, the sampling period is predetermined, and sampling is performed at such time intervals that it is possible to humbulate data whose phases are exactly apart. If maa of the AC input waveform deviates from the originally planned frequency f0 of 1 fist by ΔjO VI (/, 1Δf, )C, the correct V is y” = y”($1) + v”
(il -4(fcl+mf6))...This should be found in (2). However, %lol excluding 62 is above (1)
Since we are calculating the formula, some amount of w4* occurs. That is, as sampling data, it is necessary to use data that is slightly shifted from the relative phase difference i due to fluctuations in the phase and wave numbers, resulting in errors.

As described above, when calculating the effective value of an AC input waveform using the horizontal calculation principle, conventionally, the calculated effective value t: i14* occurs as the frequency of the AC input waveform changes.

The purpose of the corner is to calculate the effective value from the sampling value of the AC input waveform using the horizontal calculation principle, and then calculate the jlIla ridge fluctuation reef of the AC input waveform; - To provide an effective value adjustment method that can obtain accurate effective values with little difference.

孭1i[) 扭子本斯- is a certain reference frequency FIL a When the 10 AC input waveforms are sampled at a predetermined frequency, the above &Hayabusi j [a constant phase difference i in the number I・-2 , detect two sampling values having the reference frequency fo4, detect the actual frequency rILaj of the AC input waveform,
Two deviations Δf, or from this - two corresponding digits, II
II. The reference Jthllr of the actual frequency f
Increase or decrease direction g with respect to IL ridge foc: Correct the sleeve so that it becomes a sampling value with a shifted phase, and from this corrected value of 10,000, the remaining Sun 1 Linda value, and 6 2, the i-type calculation is To find the effective value, 62 yo 01 AC human power a form 1;
Correct the frequency fluctuation due to this frequency position 11g11 section -
There are six effective value measurement methods that reduce the accompanying calculation errors.

Embodiments of the Invention Hereinafter, one embodiment of the present invention will be briefly described with reference to the drawings.

II I NIL Typical wire installation # to carry out the main axis clearing method
An l4Ilt example is shown. In FIG. 1, a measuring transformer number 1 is provided for lowering the signal level 4 of the AC voltage waveform to be subjected to -j constant. The AC input waveform Fi obtained by passing through the measuring transformer l is sampled at a predetermined sampling period of -2 by the M/D conversion 62, and is converted into an analog-to-digital signal. Also, frequency transdue? (FteD) 3 outputs a level signal proportional to the frequency 6 of the AC input waveform, which is converted into a digital signal 42 representing the frequency through the A/D converter 2.

The sum/D f exchanged output #'i obtained as above
, is sent to the effective value calculation device 4I, and this ζ uses the value obtained by supplementing the AC input sampling value with the frequency input to calculate the spear shape 3! Gland 1llI: From 5 to calculate the effective value.
and configure it.

AC current #1. Form 1: IIL, by processing the AC input waveform obtained through the change #l function 5 to lower the signal level with the AC voltage waveform, it is possible to obtain the frequency axis pressure. It is possible to calculate the effective value of
The principle operation of Ippon envy (I) will be explained with reference to Figure 2. If the circumference flL of the solid line of the AC input waveform obtained from the transformer wheel lC2 shown in 甽1&A is still determined first, the AC input JIil and the number from Io to, for example, j, cj, +Δf, > l: % if fluctuated
Essay 2-5: As shown, the relative phase difference between the two actually sampled data is still the same.

Therefore, with the input of the effective value calculation (b) path, this frequency transducer data ≦; In addition, from the frequency transducer, 0jli1 wave number ゛signal wave number input, -s This frequency mm11 Δj, t=depending After correcting one side of the sampling data so that the relative phase difference is exactly 6 apart, Digital median correction due to fluctuations - differences can be corrected.

Next, the specific method of the present invention will be explained with reference to the 31st 70-chart.

Sampling data for one period of AC input ogiform from the Mu/D conversion unit 2 shown in 1st line 1st order 5cb value performance @ 4
(step a). However, this sampling frequency shall be several times higher than each other (multiple times the cost). Then, the part where the polarity of this sampling data changes from negative to positive or positive to positive or negative, or two sampling data, for example, the sampling data V(sx) and V(ts) of 壓 4 evil are polished (step' b). The above-mentioned polarity change part 1i is a part where the linearity of the waveform is well maintained, which is the 0th order g;, a frequency transducer (PTD).
Step C) Input the actual frequency f·' of the 5eR input waveform and compare the magnitude with the frequency f0, which is the standard for determining the percentage of insects (Step a). The size of fo' and j is t-Fifo > fo o and 10'< /a
There are two possibilities for case o, but decide which one,
Perform calculations as shown below.

■ In the case of f-'> jo (temporarily add 9' = 1. ÷ m j0) As shown in the 4th section, the @ of the waveform between Sun 1 Rin l data V (tl) and V ($1) lll1 sex is 1
111 ft-Ill tell you what to do! j:V(sl)
And V(Im) day z or bmnJlc! Then, calculate the 1m positive data V ($1″) from the lower tree (step
). This correction data V (%e') has a phase difference with the sampling data V (t,) of frequency 1. '=1. +ΔfC
; 0, which is the correction data that suppresses the two-phase RT, and this sampling data V(S,) and -positive amount V(11'
) can be used to calculate the effective value according to the test method.
Step no), it is possible to calculate almost no effective value of #i depending on the frequency.

V(t1') = 1(IT(tIN+1v(sl month)
Δj.

x (4i.(7°.4j,)/(,;))−1v(s
1 river/s: Sample the cycle animal number ■i, if '<i, (temporarily add 9' = j0 - Δ9)
Continuation 5---As shown above, from the sampling data V(tl) and V($3), the circulation data v<s@'> is calculated by the following formula from the sampling data V(tl) and V($3). calculate(
Step g). The phase difference between this correction data V (Ss') $1 and the nangling data V ($4) is the chest wave number 9' = j
This is the data that corresponds to the length of the curtain at 0-Δj. Then, this sampling data V ($4) and correction value V (ml
') is used to calculate the effective value of ``I/# creation:'' (Step h) tl of I#4 difference depending on s frequency
An incredible effective value can be calculated.

V(tg')=1(IV($1 month+IV(1,)l
)j, : Sampling lll4tIL number As mentioned in IVI in terms of 110 and ■ product, the case of 9′〉jo; sampling date V($1) and V($9)i
o'<1. In the case of; sampling data fi V (%s)
JILU V (Using $43 12% Breast fI
For m- due to L number variation. The sampling data was corrected for the part where 1 ml of wax was also preserved (tX and tsQ).
Seki) and Takenaujin is established.

More than the overall effect, Motoya Akira Kanjiyore is 31 horizontal performances! When calculating the AC human force 5wl value from the AC human force C2, even if there is a change in the number of AC human force 62 pectoral ridges, an effective fli performance without any fIi can be realized.

[Brief explanation of the drawing]

Fig. 1 is a pull circuit diagram showing an example of a digital effective performance circuit executed by the method of the present invention, Fig. 2 is a waveform diagram explaining the ATM-like operation of the present invention, and Fig. Flowchart showing an embodiment of the value estimation method, No. 4
Figure 5 and Figure 5 are waveform diagrams for explaining the operation in the method shown in Figure 3. 1... Meter transformer 2... Analog digital converter 5-saIIL transducer 4... Effective value arithmetic device 5... Transformer tlL mackerel (7J1
17) Daikajin Ben-vagina Nori Kugi Maro Yu (#Bon or 1 person) Figure 1 Figure 2 Figure 4 Figure 51!1

Claims (1)

[Claims] (1) When the 0 frequency *jtso AC input liquid type, which is a certain reference, is numbered by copying the predetermined frequency, the frequency f11. 3 with a certain phase difference)
and detect the AC incoming wave y#
Detect the frequency ft and use the reference frequency j
ot2 deviation Δ/, from this ε: corresponding phase to the seem wave number, the reference circumferential trajectory I: increase or decrease relative to it: 62 correction so that the sampling value of the shifted phase is obtained, and this correction The effective value is determined by the product calculation thickness layer from the one value, meOt, and the ring l value. The number of cycles tILII
When we do nangrin l with kl, c:, the directness of the liquid form of this AC input waveform is almost maintained, and the inversion point of WN is 2.
two sampling values V($1), v(tg) and these two samplings *V($1)+V(til)1
Two pairs of sampling values V($11)IT(s4) each having a constant phase difference i at the reference frequency m
and detect the actual dependent wave number 1- of the AC input waveform to determine the magnitude relationship with respect to the reference frequency *i.
, > I in jo; If the value is j0 + Δj0, from the two samplings mV (sx) and V (tm), the correction value v (white is stored as 11 V (S8)) according to the Cabinet method: From the horizontal calculation, the effective value of W is calculated. If f′o<jo and 8=/, -Δf0, calculate the correction value 'V(l') by 12 from the Sokaku method-2, and combine this correction value V($11') with the above sample. An effective value measurement method in which the effective value is determined using the horizontal calculation principle using the 1-ring V (No. 4).