SU991616A1 - Method of testing redundancy generator - Google Patents

Description

(54) METHOD FOR CONTROLLING A BACKUP GENERATOR

one

The invention relates to a pulse technique and can be used in automation and computing to control the deviation of the pulse frequency of the generators.

A known method of monitoring redundant generators is based on converting the pulse signals of the backup generators into a constant voltage and monitoring changes in the constant voltage that occur when the backup generator 1 stops working.

 The disadvantage of this method is the inability to control the pulse frequency, which limits the possibility of its use.

Closest to the invention is a method for monitoring redundant. generators, allowing to control the deviation of the pulse frequency of the backup generator 2.

In the known method, the time interval corresponding to the pulse period of the backup channel is compared with the time interval of a fixed duration, which is formed with the help of an auxiliary reference generator of written accuracy. The deviation of the pulse repetition period of the backup channel for different values is used; the formation of the control signal to turn off the faulty channel. Offset of time intervals corresponding to the periods of the pulse generator back-up generators relative to the boundary

10 time intervals occur not only when the pulse frequency of the monitored generator deviates, but also when the reference generator malfunctions, causing changes in the pulse frequency of its pulses, therefore, as a result of the control, there can be no unambiguous decision whether the monitored generator failed or the malfunction occurred reference generator, which reduces the reliability of the control and limits the control possibilities.  In addition, the known method cannot be used in autonomous control systems, when the reference time intervals cannot be set from the outside, which also limits the control possibilities.  The aim of the invention is to expand the possibilities of control.  The goal is achieved according to the method of controlling a redundant generator based on filling the period of the generator frequency with pulses and comparing the result obtained with the boundary value, allocating the period of the difference frequency of the pairwise taken backup generators, filling the selected period with the difference frequency of one of the generators of the pair the result obtained is compared with the boundary value, the i-ro failure of the generator is determined by the formula f, -fiM where f-, f, are the frequencies 1 and (i + l) -ro of the generator 1 1 -and N is the result of complements difference frequency period i and (i + l) i-ro frequency generator -ro generators; N p - the boundary value.  Consider the control method on the example of a three-channel pulse generator, containing three standby generators.  Allocating difference frequencies, resulting in a pulse sequence of three difference frequencies, the pulse-periods of pbFx are; (); (1-16); () jp pulse repetition frequency of the alternators, respectively, on the first, second and third channels.  After filling the periods of following pulses of difference frequencies (), (1-16) and (1-1c) with the pulses of the backup generators, respectively, of the first, second and third channels and counting the numbers of pulses, we obtain the values of the numbers of pulses Nj, N5, N3, equal to: Represented pulse frequency on an arbitrary t-th channel as a sum of the nominal value of f and a deviation from this nominal value of Af.  , t  e.  f, - fo - Af Let us choose the limiting value N „of the number of pulses as follows: Γ -Z-uSo where Af is the absolute value of the maximum deviation of the pulse frequency of the backup generator, corresponding to its healthy state of operability without disturbances Oo (1-6) a сГ - limiting relative deviation of the pulse repetition frequency of the backup generator. Comparing the readings of the counters N ,, Nj and N3 with the limit value allows to fix the violation of the performance of the backup generator.  The normal operation of the backup generators without disturbances corresponds to large values of the numbers of igpuls pulses, t.  but.  N 7 / MgT N2-7 / Nrp, N37 / (1-8) If any channel of the generator fails, leading to a pulse frequency deviation, the values of the number of pulses N y are reduced to two channels, as the selected difference frequency increases. the corresponding channels, the decrease in N readings below the limit value N, allows to fix the occurring violation and to determine the channel in which the violation occurred, Fig.  1 shows a block diagram of a device that implements the proposed method; in fig. 2 timing charts of the device.  The device contains backup generators 1-1, 1-2 and 1-3, blocks 2-1, 2-2, 2-3 allocations of difference frequencies, triggers 3-1, 3-2, 3-3 counting, built on the principle of two-stage storing information with outputs from the first and second stages, counters, 4-2 and 4-3 pulses, registers 5-1, 5-2 and 5-3, blocks 6-1, 6-2 and 6-3 comparisons, AND elements 7-1, 7-2, 7-3, 8-1, 8-2, 8-3, 9-1, 9-2, 9-3.  59 The output of generator 1-1 is connected to the first inputs of a block 2-1 in the gap section and an element 7-1 of the same channel and to the second input of a block 2-3 to allocate the difference frequency of the third channel.  The output of generator 1-2 is connected to the first inputs of block 2-2 and element 7-2 of the same channel and to the second input of block 2-1 for allocating the difference frequency of the first channel.  The output of the generator 1-3 is connected to the first O block inputs of the block 2-3 and element I 7-3 of the same channel and to the second input of the block 2-3 of the second channel.  The counting inputs of the triggers 3-1 - 3-3 are connected to the outputs of blocks 2-1 - 2-3 of the corresponding channels.  The direct outputs from the first stage of the flip-flops 3-1 to 3-3 are connected to the second inputs of the element I And 7-1 to 7-3 of the corresponding channels, and the inverse outputs to the first inputs of the elements And 8-1 8-3 and 9-1 - 9-3 corresponding channels.  The direct outputs from the second stage of the flip-flops 3-1-3-3-3 are connected to the second inputs of the elements AND 9-1 to 9-3 of the respective channels, and the inverse outputs to the second inputs of the elements 8-1 to 8-3 of the corresponding channels.  The outputs of the And 1-1 - 7-3 elements are connected to the summing inputs of the counters 4-1 - 4-3 of the corresponding channels, the reset inputs of which are connected to the outputs of the And 8-1 elements - 8-3 of the corresponding channels.  The bits of counters 4-1 through 4-3 are connected to the inputs of registers 5-1 through 5-3 of the corresponding channels.  The inputs of the sync and registers 5-1 - 5-3 are connected to the outputs of the elements And 9-1 - 9-3 of the corresponding channels.  The outputs of registers 5-1 to 5-3 are connected to one input of blocks 6-1 to 6-3 of the comparison of the corresponding channels, to the other inputs of which external value codes, N, NTO-, are supplied from the outside through corresponding channels.  A device for implementing the method works as follows.  In the initial state ycTposiCTBa on the direct outputs of the triggers 3-1 - 3-3 and on v: the moves of the elements And 7-1 - 7-3, 9-1 - 9-3 zero signals, counters 4-1 - 4-3 held in the Zero state by single signals arriving at the installation inputs from the And 8-1 - 8-3 capacitors.  The inputs of block 2 in the differential frequency of each channel receive pulses from the backup generators 1 corresponding to the channel and the subsequent channel.  In the codes of block 2, the differential frequency pulses of pairwise redundant generators 1 of all 6 channels that arrive at the counting inputs of the trigger 3 of the respective channels and cause switching of the trigger 3, while the signals at the outputs from the first stage of the trigger 3, vary along the forward freet of the counting pulse and the signals at the inputs from the second stage of the flip-flops 3 are on the falling edge.  At time tj (the time axis t in the timing diagram of FIG.  2) a pulse is formed at the output 2-1 (time diagram W2). / j in FIG.  2), which enters the trigger input 3-1, while a single signal is set at the direct output from the first stage of the trigger, and a zero signal is set at the inverse, which enters the inputs of the AND elements 8-1 and 9-1 and closes them.  At the output of the AND element 8-1, a zero signal is set (timing diagram Ug in FIG. 2), thereby resetting the reset signal of the counter 4-1.  The unit signal from the output (direct) from the first stage of the trigger 3-1 is fed to the input of the terminal And 7-1 opens it, the pulses from the generator II cough through the element 7-1 to mm1 of the counter 4- 1, the reading of which begins to increase (time diagrams.  Ud-; pas figs. 2).  During normal operation of the backup generators 1, the frequency of the outgoing pulses of the channels is close, therefore, since the pulses of the differential frequency are large.  during the time interval between SMS pulses, the reading of the counter 4-1 has time to increase to a value greater than the limit.  The next pulse from block 2-1 (time t in FIG.  2) arrives at the counting start of the trigger 3-1 and causes it to switch, while at the forward stage of the trigger stage 3-1 the zero signal is set, which arrives at the input of the element And 7-1 and closes it, thereby stopping the pulses on the summing counter input 4-1, At the inverse output from the first stage of the trigger 3-1 by setting. Injects a single signal, which is sent to the input of the AND 9-1 element, to another input which receives a single signal from the direct output from the second stage of the trigger 3-1.  The impulse from the output of the AND 9-1 element is fed to the synchronization input of the regaster 5-1 and allows the recording of the counter 4- to the register 5-1.  The readout of the counter 4-1 recorded on the register 5-1 goes to one input of the block 6-1 and is compared with the supplied other inputs by the boundary value N, and the normal operation of the reserve ones. of the generators 1 without deviations of the pulse frequency corresponds to the situation when the counter reading 4-- coming from register 5-1 exceeds the visible magnitude, while the output of block 61 maintains a zero signal.  At the end of the second pulse at the input of block 2-1 (time tj in FIG.  2) at the direct output from the second stage | Geni trigger 3-1, a zero signal is set, which enters the input of the element AND 9-1 and closes it.  At the inverse output from the second stage of the trigger 3-1, a single signal KOTOpbtH is set at the input of the element And 8-1, and another input of which receives a single signal from the inverse output from the first stage of the trigger 3-1.  At the output of the element And 8-1, a single signal is set, which is fed to the reset input of the counter 4-1 and returns it to its original state.  The next impulse from the output of block 2-1 (time instant t 4 in FIG.  2) enters the counting input of the trigger 3-1 and switches to the 3-state in which one, at the inverse output from the first stage of the trigger 3-1, a zero signal is set, which enters the input of the element 8-1 and zrygat it ( FIG.  2), thereby removing the reset signal from the installation input of the counter 4-1.  At the direct output from the first stage, the trigger 3-1 is set to a single signal (in FIG.  2), which opens one input element And 7-1, while the pulses from the generator 1 - 1 through the element And 7-1 begin to flow to the counter 4-1.  The counter reading 4-1 begins to increase (in FIG. 2).  Suppose a malfunction is produced, for example, a 1-2 generator.  as a result of which the pulse frequency at the output of the generator 1-1 is mixed (increased sludge decreased), so the difference pulse frequency at the output of block 2-1 increased, and the pulse period decreased.  Then the next impulse from the output of the block 2-1 will arrive somewhat earlier than during normal operation of the generators (time t; fig.  2), t, e.  earlier than the counter reading 4-1 exceeds the limit value.  On the leading edge of this pulse, ifocTyTiamuero, at the counting input of the trigger 3-1, a zero signal is set at the direct output from the first stage of the trigger 3-1 ((3-1 in FIG.  2), and on the inverse one.  The zero signal from the direct output from the first stage of the trigger 3-1 closes the element And 7-1 and the pulses from the generator 1 - 1 cease to flow through the element And 7-1 to the summing input of the counter 4-1.  A single signal from the inverse output from the first stage of the trigger 3-1 enters the element 8 and 1: 0 ,,: squeezes it out to one input to act, and also enters the input of element 9 9-1, to the other input one signal from the direct output from the second stage of the trigger 3-1.  The pulse from the output of the element And 9-1 is fed to the synchronization input of the register 5-1 (U.  in fig. 2), the code value on register 5-1 decreases, since a reading less than the limit one is recorded from counter 4-1 on it.  The code from register 5-1 goes to one input of block 6-1 and is compared with the boundary value supplied to other inputs, and since the code value from register 5-1 is less than the limit N. -01 a single sigal is formed at the output of block 6-1 (U, in FIG. 2), which indicates a malfunction, one of the channels of the generator.  At time te (the time axis t in FIG.  2) at the end of the pulse from block 2-, arriving at the counting input of the trigger 3-1, a zero signal is set at the direct output from the second stage of the trigger 3-1, and a single signal at the inverse output.  The zero signal from the direct input from the second stage of the trigger 3-1 closes down the element 9-1 (Ug in FIG.  2), thereby terminating the pulse at the synchronization input of register 5-1.  A single signal from the inverse output from the second stage of the trigger 3-1 through the element 8-1 prepared by another input enters the reset input of the counter 4-1, and the counter returns to its initial state (U4- in FIG.  2).  At time l (the time axis t in FIG.  2) the next pulse from the block (Uj in FIG.  2) arrives at the counting input of the trigger 3-1, and at the direct output from the first stage of the trigger 3-1 a single signal is set, and at the inverse output it is zero.  The zero signal from the inverse output from the first stage of the trigger 3-1 closes the inputs; elements AND 8-1, 9-1, thereby setting the output of element AND 8-1 to a zero signal (Us. 1 in FIG.  2) and the reset signal of the counter 4-1 is terminated.  A single signal from the direct output from the first stage of the trigger 3-1 opens element I 7-1 at the input and pulses from the generator 1-1 to the summing input of the counter 4-1 begin to pass through it.  Further operation of the first channel is similar.  Thus, in the event of a malfunction, for example, generator 1-2, a single signal is generated at the output of the comparison unit 6-1.  Consider the work of the second channel generator.  In the timing diagram (FIG. 2), characteristic points of time relating to the operation of the second channel are marked on another time axis for convenience of examining the processes. Pulses from the output of block 2-2 are fed to the counting input of trigger 3-2.  With the arrival of the first pulse from block 2-2 (Uj-: in FIG.  2) at time ti, at the inverse output from the first stage of the trigger 3-2, a zero signal is set, and at the direct output - a single signal (Uz-r in FIG.  2).  The zero signal from the inverse output from the first stage of the trigger 3-2 closes the elements 8-2 and 9-2 at the inputs, and the zero signal is set at the output of the element 8-2 (Ug-i in FIG.  2), thereby removing the reset signal from the installation input of the counter 4-2.  A single signal from the direct output from the first stage of the trigger 3-2 opens the input element 7-2 and one generator and pulses from the generator 1-2 through the input 7-2 arrive at the summing input of the counter 4-2, the counter begins to increase (U4 2 in FIG.  2).  During normal operation of the backup generators, the reading of the counter 4-2 reaches a value exceeding the limit Nj-p, before the second pulse arrives from the output of the block. The second pulse arrives from block 2-2 to the counting input of trigger 3-2 at the moment of time. , while at the direct output from the first stage of the trigger 3-2 a zero signal is set, and at the inverse output - a single signal.  The zero signal from the direct output from the first stage of the trigger 3-2 closes the element at 7-2 at the input, therefore the arrival of pulses to the summing input of the counter 4-2 is stopped.  A single signal from the inverse output from the first stage of the trigger 3-2 prepares one input element AND 8-2 and through element AND 9-2, opened through another input with a single signal from the direct output from the second stage trigger 3-2, increases by the synchronization input register 5-2 (U 9-2 in FIG.  2) while the register 5-2 records the counter 4-2, exceeding the limit value N The code from the register 5-2 is fed to one input of the block 6-2, which is compared with the boundary value supplied from the outside to the other inputs.  Since the reading from register 5-2 exceeds the limit value, a zero signal is held at the output of comparison block 6-2.  On the trailing edge of the pulse from block 2-2 (time of time ta in FIG.  2) at the direct output from the second stage of the trigger 3-2, a zero signal is set, and this creates a falling edge at the output of the AND 9-2 element (U9. . 2 in FIG.  2), and at the inverse output from the second stage of the trigger 3-2, a single signal is set, which, through the AND element 8-2 (the graph in FIG.  2) enters the reset input of the counter 4-2.  Counter 4-2 returns to its original state (UA. J in FIG.  2).  As before, we assume that in the time interval after the time ts, a pulse frequency deviation at the generator output 1–2 occurred, the difference pulse frequency at the output of the block 2–2 increased, and the pulse repetition period decreased.  The next pulse from the output of block 2-2 (time t in FIG.  2) switches the trigger 3-2, at the inverse output from the first stage of the trigger 3-2, a zero signal is set, thereby closing the AND 8-2 element and removing the reset of the counter 4-2.  A single signal is established at the direct output from the first stage of the trigger 3-2 (Us-j in FIG.  2), which opens element I 7-2 in one input, pulses from generator 1-2 through element And 7-2 begin to arrive at the summing input of counter 4-2, the reading of which starts to increase (U4-2 in FIG.  2), As a result of a malfunction of the generator 1-2, the pulse duration of the difference frequency at the output of block 2-2 decreased, the next pulse arrives at the input of the trigger 3-2 at time ts before the counter 4-2 reaches the boundary value.  On the leading edge of the pulse formed by the block 2-2 at the moment of time ts (in FIG.  2) at the inverse output from the first stage of the trigger 3-2, a single signal is set, and at the direct output - zero.  The zero signal from the direct output from the first stage of the trigger 3-2 closes the element 7-2 and thereby stops the further counting of the pulses of the generator 1-2.  A single signal from the inverse output from the first stage of the trigger 3-2 prepares an input element And 8-2, and also enters the input element And 9-2, to another input which receives a single signal from the direct output from the second stage trigger 3-2 .  The pulse from the code of the AND 9-2 element is fed to the input of the synchronous register 5-2, while reading the register 5-2 rewrites the counter 4-2.  The code value fixed on register 5-2 decreases (Us-j in FIG.  2), because the newly recorded value on it is less than the boundary value.

The code with perj-icjpa S-2 nocrviMei H: I block: and it is juxtaposed with the boundary –cn chain. to step on the other entrance of the block 6–6, by the output of the block 6–2, it is accelerated by one) - the third signal (. 2), SUK as an input ;; idea from the register 5-2 value vicHbuu- rpiuuiiii,

Thereby, a generator malfunction is detected during the operation.

At the moment of time if, by tweeter ii Miiyjjb sa from the output of block 2-2 (I2-2 to (lig. 2) and ;, the direct output from the second stage, trigger 3-2 sets the zero signal, which closes the input element I 9- - 2 (UG .... in FIG. 2) and thus the rewrite is stopped

on register S-2 counter 42,. on

inverse output from Iora cryiienM rpiu i g: | -; 3-2 ycTanaBjiMBaetCH ediah-FHbni signal, which is 11l. H through the element And 8-2 enters a fool. reset the counter and allow it to run in a good condition (u4-2 per 1, 2).

Thus, during the operation of generator 1-2 at the outputs of blocks 6-1 and 6-2, to form single signals.

Consider the work of the third rsanal device.

On the time diagrams (c ((|) ig. 2) related to the work of the third channel; P xap-aKiepHi je time periods for a more distinct image are marked on the third time axis t.

The emuls from the output of the 2-3 nficTyiuiior block into the 1.1V input of the trigger L 3-3

With the arrival of a nerve impulse from the block 2-3 {U2-.3 and FIG. 2) in MOMciT time. ti at the inverse output from the 3–3 chrigger and the strut of the rigger 3–3 is set up by the ryuleva sipigg ;, at the direct output — the single fU.3 ({mr. 2). The zero signal from the speed 1; (the stroke from the third stage of the trigger 3-3 is closed; but the inputs are 8-3 and 9-3, with: 0 and 8-3 the input signal has a zero signal; w (Ug-j 2), thereby, the RESPONSE is reset by the reset signal from the SETCHO} {Wow, and the counter is 4-3,

The unified sigal from the start of the third stage of the trigger 3-3 opens the input element I 7-3 and emulsions from the generator) -3 through the element 1 7-3 and 1 1yug rioctyiiarb to cy.Iyryuny input of the counter 4-3, readings of which begins to increase (lJ,. ,,, j in Fig. 2). The counter reading reaches a value exceeding the boundary Nfo earlier than the counting) the second input of the trigger 3-3 nots the second impulse from the block 2-3, since the rest n inputs of block 2-3 frequency traces; HMnyjTbsov generators 1-1 and 1-3 are close to each other and the difference frequency is small.

At time tj, the second pulse is from the output of the block 2-3 (Uj.s to () ig. 2) ILG i.pa

the register

Yi p

h and ka 4-ak KiK notes ;;: d- reglsg: ok;) :; a; .ie.; i Г ;; П1ИЧ) (1,:;} i; 4eH5; e. u ;; i НЬХОГггы (; ка 6 --- 3 ociiciCH and ıalııHiinri.

In MOMcTj time t. on the back edge) y; P; Sa pas ;; - iloca: .- 3 (IJj .., ;; i ;: f; | r. 2) AI: - hjKOiie 07 another second 3-3 mouth and chlivieyun zero signal; l1, which) is shown; iio input) 3jieMe} n AND 9-3 and heme most forlt gtuetoto back (bosh impule 3ii xp; nn3aUHM; O; Fig. 5-3 (chart J: ,,, - ii-.i fig, 2; and unit, 1 AND; chi | 1 signal from the inverse inflator :: oi; -,; -pr ;; th (,, -: zigra 3-3 through,) 1Y of another; -o; mu INPUT 1-- element I 8--3 g-, 1.:; Ui ;; e; on nkho, d cGnocd; -; echter 4--3. Nri W; ohm; 01 the counting of the counter -i - 3 v; voices

 ISHO.NEW COCrO; iU, - KJ.i .--) LJA-4NG. 2).

In mom t: The impulse from the block is 2-3 ps; y ;; au.- l ;; The countdown of the trigiepa, v - 3,; 1ri CROW and-: DL rsnom output from iippuoH c; -yniM is fi / Mn-cpa 3--3 succeeded in sigul zero, s; l: GB :; oiip {go viciously; 11 1 And 8--3, O- t 1st; y;:, 1x: 1de, zlementa And about 3 is accelerated ;; 7 (left sigzgal (Ug, on f) and.. Those, - send a reset signal 4--3,

On ovre-- eicho on from 7th century r; pts: s 3 5 at C a.na1 From the generator 1-3 through the element I 7-3, it is necessary to enter on the c; mm | ru ipgy in () of the detector 4-3. The testimony of the checker 4–3 age: aet (Us Jia, fig. 2) and the CPP value of the M.P. value is earlier than on the second; Sun X, trigger input of 3–3 g; rokhodkt wake; onp1I and pulse from the hypox 2-- 3 gzk as from the entrance 2--3 I act with the help of leiiepalopoB J -1 n 1-3, JOiopbie is considered to work without g arruleniy and therefore 4 -; - iO bs after; o pulse from these generators; b and between themselves. ;; The response time of 1 -,: 1 1 13 9 of the following pulses at the output of block 2-3 is low. At the time ts, the pulse from the output of the block 2-3 (Uj.j in Fig. 2) arrives at the counting input of the trigger 3-3, while at the direct output from the first stage of the trigger 3-3 a zero signal is set (Uj-jHa Fig. 2), which closes the input element And 7-3 and thereby stops further counting of the pulses by the counter 4-3. At the same time, at the inverse output from the first stage of the trigger 3-3, a single signal is set, which prepares the input element And 8-3 and through the element 9-3 enters the synchronization input of the register 5-3, 15

while on the register 5-3 the counter reading is set again.

Since the new reading of counter 4-3, which is recorded on register 5-3, exceeds the limit value N and essentially confirms the previously recorded value, the indication practically fixed on the register does not change (Us-s in Fig. 2), and the signal on the output of the block is 6-3 compared to zero

Thus, as follows from the above analysis, during normal operation of the generators 1 of all channels, zero signals act on the outputs of all 6 comparison blocks. Disruption of the operation of the backup generator 1-2 of the second channel triggers comparison blocks 6-1 and 6-2, and on outputs which in this case are set to single signals.

A violation of the operation of the generator 1-1 of the first channel is also accurately recorded, with single signals being formed at the outputs of blocks 6-1 and 6-3 of the comparison (Fig. 2, ib-3) .o

Similarly, the malfunction of the backup generator 1-3 of the third channel is fixed by comparison blocks 6-2 and 6-3, the outputs of which are set to single signals.

Boundary values of N "j, and N. are set to the inputs of blocks 6-1, 6-2 and 6-3 of the comparison from the outside, all the boundary values can be set the same if the permissible deviations of the pulse frequency of the generators 1-1, 1-2 and 1-3 of all channels are the same between by itself, i.e., the stability of all generator channels is the same, or the boundary values can be set for different channels depending on the individual characteristics of the stability of the pulse frequency of the generators.

When adverse environmental factors, such as temperature fluctuations, are affected by backup generators 1, or all backup generators are functioning under continuous conditions, filling the pulse frequency of the difference frequencies with the pulses of the corresponding backup generators and, based on the obtained number of filling pulses, it is possible to make the right decision functioning or disruption of the backup generator, which allows you to expand the possibilities of control by ensuring nor its avgonomnosti without involving template generator and by reducing the ambiguity monitoring result.

Claims (2)

1. USSR author's certificate No. 581667, cl. H 05 K 10/00, 1977. 2. USSR author's certificate number 574848, cl. H 03 L 7/00, 1977 (prototype). 6, 14, when changes in the stability characteristics of their operation should be expected, the set boundary values for the channels may change in accordance with the predicted change in the stability of the operation of the generator channels. Thus, in the proposed device, in accordance with the proposed method, the control of the generators channels is monitored and recorded. The resulting malfunction of the backup generators is fixed, and the output signals indicate a failed channel. In the proposed control method, the separation of difference frequencies was performed.