CN1142440C - 90-deg phose-lock phase shifter for measuring true reactive power - Google Patents

Abstract

The present invention relates to a 90-DEG phase-locking phase shift device for true reactive power measurement, which is composed of the circuits of a PT secondary filter LO, zero passage comparators L3: C, and L3: D, a 90-DEG phase-locking electronic phase shifter L1: a, a phase detector, an L2 two-step active filter L0, a direct current reference circuit L1: D, an error integral circuit L1: D and a pressure-controlled rheostat J2, etc. The present invention is characterized in that the phase adjustment of the 90-DEG phase-locking phase shifter is realized by the pressure-controlled rheostat J2 and the phase detector with the utilization of a logical AND-OR gate; the filters are realized by the two-step fast active filter, and the control of the angle of central frequency is set by the direct current reference circuit; the present invention adopts an SMT thick-film circuit and bulk temperature compensation is carried out. The present invention is arranged in a true reactive power transducer for realizing the precision measurement of reactive power in a power system, and the reliability of the operation of the power system is enhanced.

Description

The sinusoid wattless power measurement is with 90 ° of phose-lock phase shifters

One, technical field:

Sinusoid wattless power measurement of the present invention is with 90 ° of phose-lock phase shifters, relate to reactive energy, capacity of idle power, reactive-load compensation fields of measurement, what be particularly related to is the automatic dispatching of electric system and control, state estimation etc., it has signal filtering, cross zero balancing, phase bit comparison, frequency multiplier, error intergal amplifier, phase compensation adjustment, particularly with 90 ° of phase shift angles of signal center frequency, reach the feature of setting by regulating DC reference voltage.

Two, background technology:

Existing phase shift technology state is: with RC rc phase shifter circuit, general electronics phase-shift circuit and integration, derivative compensation formula phase-shift circuit, its amplitude versus frequency characte and phase-frequency characteristic are respectively

K _F(ω)＝1 (1)

Φ(ω)＝-[π+2tg ^-1(ω/ω ₀)] (2)

ω in its Chinese style ₀=2 π f ₀ω ₀Be centre frequency angle f ₀Be centre frequency

And measure f for power frequency ₀=50Hz is not difficult to calculate with signal frequency to centre frequency f from formula (2) ₀Change the relative 90 ° of variations of circuit in ± 5% o'clock can reach ± 2.8 °, this will cause 5% additive error.

For integration, 90 ° of phase-shift circuits of derivative compensation formula, the characteristic of its output and input as shown in the formula.

U ₀＝1/2(ω?RC+1/ωRC)·sin(ωt+90°) (3)

Though formula has been taked compensation in the circuit as can be known,, change less occasion by (3), can not satisfy the requirement of wide region, high-acruracy survey so can only be fit to frequency input signal owing to can not definitely equate with the parameter of differential RC assembly as integration.

Three, summary of the invention:

Sinusoid wattless power measurement of the present invention is exactly 90 ° of phase-locked phase shift technologies that design for the deficiency that overcomes above-mentioned several phase shift technologies with 90 ° of phose-lock phase shifters.Input, output signal carried out respectively zero balancing, phase bit comparison, frequency multiplication, dc reference, error ratio, a series of technical measures such as integration amplification, phase compensation adjustment, reach 90 ° phase-locked.Its technical process is: it is made up of PT, secondary active filter, zero-crossing comparator, 90 ° of phase shifters of phase-locking type, phase-sensitive detector, second-order active filter device, dc reference, error integrator, voltage-controlled rheostat, it is characterized in that: the U of input voltage after the PT conversion _iVoltage enters that secondary active filter filtering secondary is above humorously to divide two road signals after involving undesired signal, and one the tunnel sends into 90 ° of phase shifters of phase-locking type, and another road is input to (H) of first zero-crossing comparator ₁Input end produces a zero passage benchmark signal, and 90 ° of phase shifters of phase-locking type produce one and input signal U _iThe voltage amplitude equal phase differs from 90 ° phase-locked phase shift signal, and the phase-locked phase shift signal of generation divides two-way output, and one the tunnel is input to subsequent conditioning circuit, and another road is input to second zero-crossing comparator (H) ₂Input end produced the zero balancing feedback signal, first zero-crossing comparator (H) ₁Zero passage benchmark signal and second zero-crossing comparator (H) ₂Cross the zero balancing feedback signal, enter phase-sensitive detector, detect after the phase differential, through the second-order active filter device, be smoothed to DC voltage, and relatively produce an error voltage in the back, after error integrator amplifies with reference dc voltage E, control voltage-controlled rheostat, three control ends input of phase-sensitive detector is square wave and threshold voltage relatively, makes output and is entered as the distance relation, and phase shifter compensation input control voltage scope is-9V～-1V, centre frequency 50Hz, the frequency compensation scope is 43Hz～57Hz.Sinusoid wattless power measurement of the present invention with the obvious advantage of 90 ° of phose-lock phase shifters is: its circuit is reliable, especially adopts current high-tech surface mounting technique (SMT technology), and institute is so that reactive power measurement is correct, reliable as meritorious.

Three, description of drawings:

Fig. 1 is 90 ° of phase-locked phase-shift circuit block schemes of sinusoid wattless power measurement;

Fig. 2 is the circuit diagram of secondary active filter;

Fig. 3 is that zero passage, phase-detecting, active power filtering, error ratio are than circuit diagram;

Fig. 4 is the state oscillogram;

Fig. 5 is 90 ° of phase shifter circuit figure of phase-locking type;

Fig. 6 is the circuit analysis figure of Fig. 5;

Fig. 7 is normalization phase-shift characterisitc figure;

Fig. 8 is way circuit figure

Among Fig. 1: A-PT, B-secondary active filter, 90 ° of phase shifters of C-phase-locking type, D-error integrator, E-dc reference, F-second-order active filter device, G-phase-sensitive detector, H-zero-crossing comparator, the voltage-controlled rheostat of I-.

U _Io-input signal U _Ci-filtered signal voltage

U ₀-signal voltage U after phase-locked ₁-benchmark zero cross signal voltage

U ₂-feedback zero cross signal voltage U ₃-phase error voltage

Ug-phase control voltage R _Ds-voltage-controlled rheostat dynamic resistance value

J ₂-field effect transistor

Four, embodiment:

Below in conjunction with accompanying drawing the present invention is further described:

See that accompanying drawing 1, its course of work are as follows: the U of input voltage after TP (A) conversion _iVoltage enters that secondary active filter (B) filtering secondary is above humorously to divide two road signals after involving undesired signal, and one the tunnel sends into 90 ° of phase shifters of phase-locking type (C), and another road is input to first zero-crossing comparator (H) ₁Input end, produce a zero passage benchmark signal.90 ° of phase shifters of phase-locking type (C) produce one and input signal U _iThe voltage amplitude equal phase differs from 90 ° phase-locked phase shift signal, and the phase-locked phase shift signal of generation divides two-way output, and one the tunnel is input to subsequent conditioning circuit, and another road is input to second zero-crossing comparator (H) ₂Input end produced the zero balancing feedback signal, first zero-crossing comparator (H) ₁Zero passage benchmark signal and second zero-crossing comparator (H) ₂Cross the zero balancing feedback signal, enter phase-sensitive detector (G), detect after the phase differential, through second-order active filter device (F), be smoothed to DC voltage, and relatively produce an error voltage in the back, after error integrator (D) amplifies with reference dc voltage E, control voltage-controlled rheostat (I), thereby make the phase place of 90 ° of phase shifters of phase-locking type (C) output signal keep constant.Realize way circuit Fig. 8 by the sinusoid wattless power measurement with 90 ° of phase-locked phase-shift circuit block schemes.Press Fig. 8, its course of work is: through first, second zero-crossing comparator L ₃: C, L ₃: two waveforms of D are input to L ₂The logic XOR gate, the frequency of process XOR gate phase-detecting output is two times a signal frequency, the adjusting of centre frequency is by dc reference L ₁: output to totalizer R after D is anti-phase ₁₄, R ₁₅In, active filter has L ₃: B and rescap constitute, and phase-shift compensation is adjusted L ₁: A, J ₂Finish.Phase-sensitive detector L ₂The input of three control ends of A, B, C relatively square wave and threshold voltage, L ₂Output terminal X, Y, Z be entered as distance relation, phase shifter compensation J ₂The input control voltage scope is-9V～-1V, centre frequency 50Hz, the frequency compensation scope is 43Hz～57Hz.

Concrete feedback control procedure is as follows:

See Fig. 2, the circuit diagram of secondary active filter (B):

F-is frequency input signal Φ-phase angle difference U ₃-phase voltage

Ug-phase control voltage R _DS-voltage-controlled rheostat dynamic resistance value

The parameter of secondary active filter (B) is selected correctness, will directly influence the response time of circuit, amplitude-frequency, phase-frequency characteristic.By secondary filter (B) transport function as can be known, have only the choose reasonable component parameter just can make the gain of circuit, quality factor, cutoff frequency is guaranteed.Its transport function is:

$H\left(S\right)=\frac{\left(\frac{R_3+R_2}{R_3}\right)\&times;\frac{1}{R_1{R}_2{C}_1{C}_2}}{{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">S</figure-callout>}}^2+[\frac{1}{R_1{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}+\frac{1}{R_2{C}_2}-\frac{R_4}{R_2{R}_3{C}_2}]S+\frac{1}{R_1{R}_2{C}_1{C}_2}}---\left(4\right)$

Normal formula with secondary filter (5):

$H\left(S\right)=\frac{{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">H</figure-callout>}}_0{\mathrm{\&omega;}}_0^2}{S^2(\mathrm{\&omega;}/R)S+{\mathrm{\&omega;}}_0^2}---\left(5\right)$

Compare

$H_0=\frac{R_3+R_4}{R_3}---\left(6\right)$

${\mathrm{\&omega;}}_0=\sqrt{-\frac{1}{R_1{R}_2{C}_1{C}_2}}---\left(7\right)$

$Q={[\sqrt{\frac{R_2{C}_2}{R_1{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}}+\sqrt{\frac{R_1{C}_2}{R_2{C}_1}}-\frac{R_4}{R_3}\&CenterDot;\sqrt{\frac{R_1{C}_1}{R_2{C}_2}}]}^{-1}---\left(8\right)$

Make R ₁=R ₂=R C ₁=C ₂=C then has

${\mathrm{\&omega;}}_0=\frac{1}{\mathrm{RC}}---\left(9\right)$

$H_0=\frac{R_3{R}_4}{R_4}---\left(10\right)$

1/Q＝3-H ₀ (11)

ω ₀-cutoff frequency H ₀-gain Q-quality factor

See Fig. 3 zero passage, phase-detecting, active power filtering, error amplification;

UA, UB, through Ic ₁, Ic ₂Become square wave, undertaken becoming and the proportional duty square wave of phase place after the logical process by XOR gate again.The attitude of seeing this oscillogram Fig. 4, export through the level and smooth back of active filter V1 again with E

$V_2=\frac{T_w}{T}---\left(12\right)$

$V_3=\frac{1}{\mathrm{RC}}{\&Integral;v}_3\mathrm{dt}---\left(13\right)$

The V1 voltage of summation after error intergal is amplified removes to control voltage-controlled rheostat (I).

See that the circuit diagram of 90 ° of phase shifters of Fig. 5 phase-locking type (C) learns

So-called phase shifter is exactly under the constant condition of gain, the circuit that the phase-shift phase of frequency input signal or other circuit parameter is changed.

Ui＝U _msinωt (14)

U ₀＝U _msin(ωt+90°) (15)

$V_G={\mathrm{<figure-callout\; id="4"\; label="V"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">V</figure-callout>}}_4=\frac{1}{\mathrm{RC}}\&Integral;v_3\mathrm{dt}---\left(16\right)$

90 ° of phase shifters of phase-locking type (C), analysis chart 5, by Fig. 6 analysis as can be known:

V ₀＝ V ₀₁+ V ₀₂ (17)

Its amplitude-frequency and phase-frequency characteristic are

R ₁＝R ₂

Amplitude-frequency V _F(ω)=1 (18)

Phase frequency Φ (ω)=-| π+2tg ^-1(ω/ω ₀) | (19)

ω wherein ₀=2 π f ₀=1/R _wC _wBe centre frequency

With normalized output phase shift characteristic (Fig. 7)

Phase-shift phase

$\mathrm{\&omega;}=2t{g}^{-1}=\frac{1}{R_w{C}_w}=2t{g}^{-1}=\frac{1}{r_{\mathrm{DS}}c}---\left(20\right)$

Voltage-controlled rheostat (I)

The voltage-controlled rheostat of being controlled by FEEDBACK CONTROL voltage (I) is the JFET field effect transistor of a controllable transconductance, and when frequency changed, the voltage of phase-sensitive detector output changed thereupon. $V_G={\mathrm{<figure-callout\; id="4"\; label="V"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">V</figure-callout>}}_4=\frac{1}{\mathrm{RC}}{\&Integral;\mathrm{<figure-callout\; id="4"\; label="v"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">v</figure-callout>}}_4\mathrm{dt}$ Make γ _DSThereby the phase-frequency characteristic that changes obtains adjusting, and certainly, the change resistance of JFET and input control voltage are the relations of a linear change.

$r_{\mathrm{DS}}=\frac{r_0{\mathrm{<figure-callout\; id="0"\; label="s"\; filenames="C0012782100121.png"\; state="\{\{state\}\}">s</figure-callout>}}_0}{1-\frac{U_{\mathrm{GS}}}{V_p}}---\left(21\right)$

V in the formula _pFor r is pressed in outage _DSBe U _GS=0 o'clock dynamic resistance

The following formula explanation $\frac{1}{r_{\mathrm{DS}}}$ With U _GSFor linear relationship is to realize the key of voltage-controlled change resistance.

By above analysis, adopt the SMT thick film circuit, and carry out the bulk temperature compensation, being configured in sinusoid reactive power transmitter is the accurate measurement that electric system realizes reactive power, has improved the reliability of Operation of Electric Systems.

Claims (2)

1, a kind of sinusoid wattless power measurement is with 90 ° of phose-lock phase shifters, it is by PT (A), secondary active filter (B), zero-crossing comparator (H), 90 ° of phase shifters of phase-locking type (C), phase-sensitive detector (G), second-order active filter device (F), dc reference (E), error integrator (D), voltage-controlled rheostat (I) is formed, it is characterized in that: input voltage enters through (Ui) voltage after PT (A) conversion and humorously more than secondary active filter (B) the filtering secondary divides two road signals after involving undesired signal, one the tunnel sends into 90 ° of phase shifters of phase-locking type (C), and another road is input to the first zero-crossing comparator (H ₁) input end, produce a zero passage benchmark signal, 90 ° of phase shifters of phase-locking type (C), produce one with input signal (U ₁) the voltage amplitude equal phase differs from 90 ° phase-locked phase shift signal, the phase-locked phase shift signal of generation divides two-way output, and one the tunnel is input to subsequent conditioning circuit, and another road is input to the second zero-crossing comparator (H ₂) input end produced the zero balancing feedback signal, the first zero-crossing comparator (H ₁) the zero passage benchmark signal and the second zero-crossing comparator (H ₂) cross the zero balancing feedback signal, enter phase-sensitive detector (G), detect after the phase differential, through second-order active filter device (F), be smoothed to DC voltage, and relatively produce an error voltage in the back with reference dc voltage E, after error integrator (D) amplifies, control voltage-controlled rheostat (I).

2, sinusoid wattless power measurement according to claim 1 is with 90 ° of phose-lock phase shifters, it is characterized in that: three control end inputs of phase-sensitive detector are square wave and threshold voltage relatively, make three outputs and be entered as the distance relation, phase shifter compensation input control voltage scope is-9V～-1V, centre frequency 50Hz, the frequency compensation scope is 43Hz～57Hz.

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