CN1025767C - AC current-voltage mutual inductor - Google Patents

Abstract

The present invention relates to an AC current-voltage mutual inductor which is composed of an iron core and coils. Three coils are wound on a closed magnetic circuit iron core which is made of silicon steel sheets, wherein one coil is a primary coil L1 which is connected in series with a main circuit, and the number of turns is W1; another coil is a balance coil L0 of a leading-out terminal short circuit, and the number of turns is W0; the third coil is a voltage coil L2, and the number of turns is W2. The AC current-voltage mutual inductor can convert AC current into AC voltage proportionally. The present invention is used for detecting, controlling and protecting circuits.

Description

AC current-voltage mutual inductor

The present invention is an AC current-voltage mutual inductor, simple sinusoidal alternating current can be converted to the sinusoidal voltage amount pro rata.

Present existing current transformer can only be transformed into new alternating current to alternating current pro rata, and the secondary open circuit that do not allow uses.Therefore, this instrument transformer can't obtain voltage signal.And present many detections, control and protective circuit need ac flow is transformed to proportional voltage, so that be complementary with input.

The objective of the invention is to propose a kind of AC current-voltage mutual inductor, simple sinusoidal alternating current is transformed into sinusoidal voltage pro rata, to satisfy actual detected, the needs of aspects such as control.

Major technique content of the present invention is: this AC current-voltage mutual inductor is made up of iron core and coil, is wound with three coils on the annular closed magnetic circuit made from silicon steel sheet or other soft magnetic materials, and one is the primary coil L that is connected in series to main circuit ₁, another is balance coil L ₀, the 3rd is potential winding L ₂; Its structure is for being tied with insulating barrier on annular core, the insulating barrier outside is balance coil L ₀, the number of turn is W ₀, the head end of balance coil is in the same place with terminal short circuit, and promptly balance coil does not have outlet; The balance coil outside is a second layer insulating barrier, and the outside of second layer insulating barrier is potential winding L ₂, its number of turn W ₂, line directly is 0.03～0.1 millimeter, its leading-out terminal is drawn, round-meshed plastic casing in the middle of outermost is surrounded by, potential winding L ₂Leading-out terminal receive on two binding posts on the plastic casing; Primary coil L ₁, the number of turn is W ₁, W ₁The number of turn can be 1 circle or multiturn, L ₁Pass middle hole of plastic housing and main circuit series connection, be the core-theaded type AC voltage transformer.

The iron core of this AC voltage transformer can be E shape iron core, is wound with balance coil L on E shape core insulation skeleton ₀, the number of turn is W ₀, with L ₀Head end and terminal short circuit be L together ₀No leading-out terminal, its outside is an insulating barrier; Insulating barrier is outward potential winding L ₂, the number of turn is W ₂, line directly is 0.03～0.1 millimeter, L ₂Two outlets guide on two voltage terminal on the skeleton L ₂Skin be second layer insulating barrier; Be around with current coil L at second layer insulating barrier ₁, the number of turn is W ₁, L ₁Outlet receive on current terminal of skeleton, the outside is an insulating barrier also, makes the shell-type current-voltage transformer.

The potential winding L of this AC current-voltage mutual inductor ₂Also can be many group coils, every group of coil separates with insulating barrier, and its number of turn can design by magnitude of voltage as required, and its leading-out terminal is drawn out on the correspondent voltage terminal.

The operation principle of this AC current-voltage mutual inductor is according to following calculating gained.

As shown in Figure 1, at primary coil L ₁The middle simple sinusoidal alternating current I that feeds ₁, then form magnetic potential I ₁W ₁, because balance coil L ₀Be short circuit, so at magnetic potential I ₁W ₁Effect produce down induced current I ₀, its magnetic potential is I ₀W ₀, and this magnetic potential is to magnetic potential I ₁W ₁The magnetic potential of degaussing, the magnetic flux in the magnetic circuit is at this moment:

φ=(I ₁W ₁-I ₀W ₀The R of)/(Rm) ₁It is the magnetic resistance of closed magnetic circuit

Because alternating flux φ passes potential winding L simultaneously ₂So, at L ₂Two ends induce electromotive force E ₂:

E ₂＝-W ₂(dφ)/(dt)

Voltage U ₂Be u ₂=-E ₂=W ₂(d φ)/(dt)

Like this at primary coil L ₁Input simple sinusoidal alternating current I ₁After, at potential winding L ₂On induce voltage u ₂

Principle is described as follows: when simple sinusoidal alternating current feeds coil L ₁The time, produce magnetic potential I ₁W ₁, the magnetic flux that this magnetic potential produces is at balance coil L ₀The middle induced current I that produces ₀, its magnetic potential is I ₀W ₀By the principles of electric and electronic engineering as can be known, I ₀W ₀To I ₁W ₁Play demagnetizing effect, this moment, the closed magnetic circuit magnetic flux was:

φ=(I ₁W ₁-I ₀W ₀)/(Rm) (1) R _m-magnetic resistance

Magnetic flux φ is at balance coil L ₀The electromotive force of middle induction is:

e ₀＝-W ₀(dφ)/(dt)

Induced voltage u ₀=-e ₀=W ₀(d φ)/(dt) establishes balance coil L ₀Short-circuit impedance be Z ₀Induced current then:

I ₀=(W ₀)/(Z ₀) (d φ)/(dt) substitution (1) formula gets:

$\mathrm{\phi =}\frac{W_1}{\mathrm{Rm}}{\mathrm{·I}}_1-\frac{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{{\mathrm{RmZ}}_0}·\frac{\mathrm{d\phi }}{\mathrm{dt}}\mathrm{(2)}$

Make K ₁=(W ₁)/(Rm) ${\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2=\frac{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{{\mathrm{RmZ}}_0}$ ∵ I again ₁Be simple sinusoidal alternating current

I ₁＝I ₁mSinωt

Substitution (2) formula gets:

φ＝K ₁I ₁mSinωt-K ₂(dφ)/(dt)

Separate this differential equation:

Turn canonical form into:

(dφ)/(dt) + (φ)/(K ₂) = (K ₁)/(K ₂) I ₁mSinωt

Solve: ${\mathrm{\phi \; =ce}}^{-\frac{t}{R_0}}-\frac{K_1\sqrt{{\mathrm{1+K}}^2{}_2{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^2}}{{\mathrm{1-<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}^2{}_2{\omega }^2}{I}_1\mathrm{mCos(\omega \; t+arctg}\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\omega })$

Determine integral constant C:

(I during t=0 ₁Connect moment)

$e^{-\frac{t}{K_0}}\mathrm{=1}$

Because during t=0, I ₁=0 φ=0

So ${\mathrm{ce}}^{-\frac{t}{K_0}}\mathrm{=0}$ ∴ C=0 is ∵ K again ² ₂ω ²＞＞1

$\mathrm{\therefore \phi =-}\frac{K_1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\omega }{I}_1\mathrm{mCos(\omega \; t+arctg}\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\omega })$

Because φ passes potential winding L ₂So at L ₂Two ends produce induced potential e.

e ₂＝-W ₂(dφ)/(dt)

$\mathrm{=-〔-}\frac{K_1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\omega }{I}_{1}m\frac{\mathrm{d\; Cos(\omega \; t+arctg}\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\omega })}{\mathrm{dt}}〕$

＝－W ₂(K ₁)/(K ₂) I ₁mSin(ωt+arctg 1/(K ₂ω) )

U ₂＝-e ₂=W ₂(K2)/(K1) I ₁mSin(ωt+arctg 1/(K2ω) )

With K ₁=(W ₁)/(Rm) ${\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">K</figure-callout>}}_2=\frac{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{{\mathrm{RmZ}}_0}$ The substitution following formula gets:

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{W_1{W}_2}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{Z}_{0}I{}_1\mathrm{mSin(\omega \; t+arctg}\frac{{\mathrm{RmZ}}_0}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0\omega })$

$\mathrm{\phi \; ＝arctg}\frac{{\mathrm{RmZ}}_0}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0\omega }$

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{W_1{W}_2}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{Z}_{0}I{}_1\mathrm{mSin(\omega \; t+\phi )\; (3)}$

Voltage effective value

$U_2=\frac{W_1{W}_2}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{Z}_{0}I{}_1$

Formula (3) has illustrated:

1) as the not too big Z of Rm ₀→ 0(Z ₀Be L ₀Short-circuit impedance when leaking

W ₀ω＞＞R _mZ ₀The time anti-X ₀→ 0 o'clock $\sqrt{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">R</figure-callout>}{}^2{}_0\mathrm{+<figure-callout\; id="2"\; label="X"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">X</figure-callout>}{}^2{}_0}{\mathrm{\approx R}}_0$ Be L ₀

Resistance)

$\mathrm{\phi \; =arctg}\frac{{\mathrm{RmZ}}_0}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0\omega }\mathrm{\to 0}$

Be voltage u ₂With input current I ₁Same-phase.

2) output voltage u ₂(work as W for sinusoidal wave ² ₀ω＞＞R _mZ ₀The time)

3) voltage u ₂And W ₁, W ₂, Z ₀Be directly proportional and W ₀Be inversely proportional to, this shows to increase and decrease coil L as required ₂Number of turn W ₂Satisfy output voltage V ₂The needs of size.In addition also can be as required on magnetic circuit again around one or many coils to obtain more voltage signal.

4）∵ $\frac{W_1{W}_2}{W^2{}_0}{Z}_0$ It is constant

So voltage $V_{}$ ${}_2=\frac{W_1{W}_2}{{\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="921105096\_DRIMG1.png,921105096\_DRIMG2.png"\; state="\{\{state\}\}">W</figure-callout>}}^2{}_0}{Z}_{0}I{}_1$ With input current I ₁, linear.

Simple sinusoidal alternating current I like this ₁By this AC current-voltage mutual inductor primary coil L ₁The time, at potential winding L ₂Two ends obtain and I ₁Synchronous linear sinusoidal voltage.

Technique effect of the present invention is that this AC current-voltage mutual inductor is that simple sinusoidal alternating current is transformed into sinusoidal voltage, can be applicable to detect, the input of control and protective circuit, satisfies actual needs.Simultaneously to have a waveform distortion factor little for the voltage after the conversion, and voltage and input current after the conversion are linear, the synchronous characteristics of voltage and electric current.This instrument transformer can adapt to the simple sinusoidal alternating current of any numerical value in addition, and the voltage swing after the conversion can design as required, and the plurality of voltages of exportable different value or identical value satisfies the needs of different situations.This instrument transformer, it is little to have a volume, saves into material, and cost is low, the advantage that original edge voltage falls little (less than 0.04 volt), save the energy.Can make versions such as punching, shell-type as required.

Fig. 1 makes core-theaded type AC voltage transformer structural representation for the present invention;

Fig. 2 makes shell-type AC current-voltage mutual inductor contour structures schematic diagram for the present invention;

Fig. 3 is the AC current-voltage mutual inductor circuit theory diagrams;

Fig. 4 inserts the external circuit schematic diagram for AC current-voltage mutual inductor;

Fig. 5 is the i-v curve of actual measurement.

1 primary coil L ₁, 2 annular cores, 3 potential winding L ₂, 4 balance coil L ₀, 2 ' E font iron core, 5 coil racks, 6 detections, control or protective circuit 7 AC current-voltage mutual inductors, 8 main circuit loads, I ₁Input current, V ₂Output voltage, V ₂=f(I) current-voltage correlation line.

The using method of this AC current-voltage mutual inductor, as shown in Figure 4, with current coil L ₁Be serially connected with in the main circuit potential winding L ₂Connecing detection, control and protective circuit gets final product.

This instrument transformer L ₁, L ₂, L ₀Line warp and number of turn W ₁, W ₂, W ₀Can select according to actual needs.

Claims (3)

1, a kind of AC current-voltage mutual inductor is made up of iron core and coil, is characterized in being wound with three coils on the annular closed magnetic circuit iron core made from silicon steel sheet or other soft magnetic materials, and one is the primary coil L that is connected in series to main circuit ₁, another is balance coil L ₀, the 3rd is potential winding L ₂Be tied with insulating barrier on annular core, the insulating barrier outside is balance coil L ₀The number of turn is W ₀, the head end of balance coil is in the same place with terminal short circuit, and promptly balance coil does not have outlet; The balance coil outside is a second layer insulating barrier, and the outside of second layer insulating barrier is potential winding L ₂, its number of turn W ₂, line directly is 0.03～0.1 millimeter, its leading-out terminal is drawn; Round-meshed plastic casing in the middle of outermost is surrounded by, potential winding L ₂The outlet termination with on two binding posts on the plastic casing; Primary coil L ₁, the number of turn is W ₁, W ₁The number of turn can be 1 circle or multiturn, L ₁The hole and the main circuit series connection of passing the plastic housing centre are the core-theaded type AC voltage transformer.

2, a kind of AC current-voltage mutual inductor is made up of iron core and coil, it is characterized in that iron core is an E shape iron core, is wound with balance coil L on E shape core insulation skeleton ₀, the number of turn is W ₀, with L ₀Head end and the terminal short circuit (L that is in the same place ₀No leading-out terminal), its outside is an insulating barrier; Insulating barrier is outward potential winding L ₂, the number of turn is W ₂, line directly is 0.03～0.1 millimeter, L ₂Two outlets guide on two voltage terminal on the skeleton L ₂Skin be second layer insulating barrier; Be around with current coil L at second layer insulating barrier ₁, the number of turn is W ₁, L ₁Outlet receive on current terminal of skeleton, the outside is an insulating barrier also, makes the shell-type current-voltage transformer.

3, according to claim 1,2 described AC current-voltage mutual inductors, it is characterized in that potential winding L ₂Also can be many group coils, every group of coil separates with insulating barrier, and its number of turn can design by magnitude of voltage as required, and its leading-out terminal is drawn out on the correspondent voltage terminal.

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